Treatment with Ethylenediaminetetraacetic acid

Chelation Natural Miracle For Protecting Your Heart

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Other chelating agents

Chelating agents other than EDTA are described chemically in Fig. 2.25, and some of their properties (based in part on the excellent book of West, 1969) are listed in Table 2.11. While EGTA forms a stronger complex with Ca than does EDTA, for most other metals, except Ba and Hg, it is a weaker complexing agent than EDTA. Notably, there is a divergency of 5.79 log K units between the stability constants of the Ca and Mg complexes with EGTA (West, 1969). Compared with EDTA, CDTA has superior complexing powers and it is better than all the other chelating agents listed in complexing Mg2+ ions. From a microbiological point of view, CDTA was found by Roberts et al. (1970) and Haque & Russell (1974a,b) to be the most toxic compound to P. aeruginosa and other Gramnegative bacteria in terms of leakage, lysis and loss of viability and in extracting metal ions from isolated cell envelopes (Haque & Russell, 1976). The chelating agent HDTA corresponds to EDTA, one acetic acid of the latter...


Target proteinases metalloproteinases, metal-activated proteinases Synonyms ethylenediaminetetraacetic acid Molecular weight disodium salt, dihydrate 372.24 Effective concentration 1-10 mm. Stable in aqueous solution Stock solution 0.5 m in water, pH 8.5. Stable for months at 4 C Notes EDTA acts as a chelator of the active site zinc ion in metalloproteinases but can also inhibit other metal ion-dependent proteinases such as the calcium-dependent cysteine proteinases. EDTA may interfere with other metal-dependent biological processes

Initial considerations

Buffer composition is frequently critical for successful enzyme purification. Factors such as pH, ionic strength and nature of the buffer can all contribute to protein instability. Although selection of the optimal buffer composition is often an empirical process, some rational judgements can be made. For example, cysteine proteinases generally require the inclusion of a sulphydiyl reducing agent such as DTT or 2-mercaptoethanol in the buffers. Because heavy metals will readily inactivate cysteine proteinases, it is essential that the highest quality water and reagents be used for buffer preparation. As an added precaution, it is a good idea to also include EDTA. It should be noted that some serine proteinases and even metalloproteinases contain a sulphydiyl group whose integrity is necessary for expression of enzyme activity. Therefore, inclusion of thiol-reducing agents in buffers is not always limited to cysteine proteinases. For example, prolyl oligopeptidase (EC, a...

Sulfate fractionation

1 Add 250 ml Tris-EDTA buffer, pH 7.5-50 g of rat brains and homogenize at 4 C for 1 min in a blender at high speed. Wait 5 m in and repeat. 3 Add ammonium sulfate to 80 saturation (214 g 1) over a 30-min period. Stir for a further 30 min and centrifuge for 20 min at 20000 g. Discard the supernatant and dissolve the precipitate in a minimal amount of 10 mM Tris-EDTA buffer, pH 8.3 with the aid of a glass rod. Tris-EDTA buffers, 10 mM, pH 7.5 and pH 8.3

Selected bibliography

Tests of organ function, 53 Iron chelation therapy, 54 Other potential iron chelators, 57 Thalassaemia intermedia, 58 Acute iron poisoning, 58 Selected bibliography, 58 Tests of organ function, 53 Iron chelation therapy, 54 Other potential iron chelators, 57 Thalassaemia intermedia, 58 Acute iron poisoning, 58 Selected bibliography, 58

Uptake And Translocation Of Inorganic Pollutants

In soils metal ions are usually strongly bound to soil particles. To improve the bioavailability of metal micronutrients trees have evolved several strategies 6 , e.g. producing and secreting metal-chelating chemicals which, by chelation, mobilize iron, copper and zinc, as well as exuding protons in order to change the pH of the soil in the root zone, thereby solubilising the soil-bound metal ions 13 . The physiological and biochemical mechanisms that explain differences in metal mobility in trees are not well understood 8 . Since in trees metals are transported through the xylem their mobility towards the shoots may be strongly retarded by the high cation exchange capacity of the xylem cell walls. As a result, anionic metal-chelate complexes are more efficiently transported in the transpiration stream. Thus, in the practice of dendroremediation, uptake and accumulation of metals in aerial tissues of plants can be enhanced through the application synthetic and or natural chelating...

Basic Strategy of Extracting and Purifying Photoproteins

The basic principle is to extract a photoprotein in an aqueous solution and purify the photoprotein by various means of protein purification, all under conditions that prevent the luminescence and denaturation of the protein molecules. Thus, the luminescence system must be reversibly inhibited during the extraction and purification of a photoprotein. The method of reversible inhibition differs depending on the nature and cofactor requirement ofthe system to be isolated. For example, the calcium chelator EDTA or EGTA is used to inhibit the luminescence of the Ca +-sensitive photoproteins of coelenterates and ctenophores such as aequorin, obelin, and mnemiopsin (Shimomura et al.,1962 Campbell 1974 Hastings and Morin 1968 Ward and Seliger 1974). Before the discovery ofthe Ca + requirement, however, aequorin was extracted with a pH 4 buffer that reversibly inactivated the photoprotein (Shimomura et al. 1962 Shimomura 1995c). In the case of the luminescence systems of Chaetopterus and...

Iron loading anaemias

Removal of iron is essential in patients with transfusion-dependent anaemias, such as thalassaemia major, to prevent death from iron overload, usually due to cardiac failure or arrythmia. Intake of iron ranges from 0.32 to 0.64 mg kg of body weight daily in splenectomized thalassaemia major patients, derived from 100-200 mL of pure red cells per kg per year. The iron content of each transfusion is volume (mL) X haematocrit X 1.16 mg. Patients with anaemias associated with increased iron absorption, e.g. thalassaemia intermedia, who are too anaemic to be venesected to remove iron, may also require iron chelation therapy, although the rate of iron loading is considerably lower at about 0.1 mg kg per day. The only iron-chelating drug widely available is desferrioxamine (DFX). This is orally inactive and given by slow subcutaneous or intravenous infusion. Deferiprone, an orally active iron chelator, first used clinically in 1987, is now licensed for DFX 'failures' in over 40 countries,...

Hydrophobic Interaction Chromatography

Butyl-Sepharose 4 Fast Flow (Pharmacia) is an excellent medium for purifying aequorin, supplementing the methods described above. Aequorin in a buffer solution containing 5-10 mM EDTA and 1.8 M ammonium sulfate is adsorbed on the column, and then aequorin is eluted with a buffer containing decreasing concentrations of ammonium sulfate and 5 mM EDTA. Aequorin elutes at an ammonium sulfate concentration between 1 M and 0.5 M. Because apoaequorin elutes at ammonium sulfate concentrations lower than 0.1 M, aequorin is cleanly separated from apoaequorin. Thus, it is possible to prepare virtually pure samples of aequorin using a single column as follows. The aequorin sample is first luminesced by the addition of a sufficient amount of Ca +. The spent solution, after dissolving 1 M ammonium sulfate, is adsorbed on a column of butyl-Sepharose 4. The apoaequorin adsorbed on the column is eluted with decreasing concentration of ammonium sulfate starting from 1 M apoaequorin elutes at an...

Nontransferrinbound iron

This is present in plasma in patients with gross iron overload. It is highly toxic, promoting the formation of free radicals causing peroxidation of membrane lipids. Part of the early improvement in liver and cardiac function with chelation therapy may be due to removal of this fraction, even before iron burden is substantially lowered. Its clearance by DFX is short lived as it reappears in plasma within hours of stopping an infusion. This provides a rationale for using 24-h continuous infusions in patients with iron-induced cardiomyopathy. Non-transferrin-bound iron is absent from plasma of well-chelated patients.

Thalassaemia intermedia

For these patients, and other severely anaemic patients who are not transfusion dependent or only need a few transfusions each year, iron loading occurs mainly through increased iron absorption. The anaemia may be too severe for venesections. DFX can be used to chelate iron but care must be taken to avoid side-effects of the drug in these moderately iron-loaded patients. Oral iron chelation with deferiprone has also been shown effective in 'de-ironing' such patients, potentially reducing serum ferritin and liver iron to normal. A rise in haemoglobin level may occur. This may be due to removing iron from the renal oxygen sensor, augmenting the effect of hypoxia and increasing erythro-poietin secretion from the kidney. The role in haemoglobin may also result from deferiprone directly removing iron from erythroblasts and mature red cells, reducing ineffective ery-thropoiesis and haemolysis. Improved haemopoiesis has also been described in myelodysplasia after chelation with DFX.

Laboratory Diagnosis

For B. divergens, oxen or, more conveniently, gerbils, can be used. After inoculation of gerbils, rapidly progressive infection and death ensues within 3-6 days (Telford et al., 1993). Suspected B. microti infection can be confirmed by the intraperitoneal inoculation of 1.0 ml EDTA-whole blood into golden hamsters.

Propidium Iodide Staining

To examine whether the cell cycles were influenced by oxygen concentration, flow cytometric analysis with propidium iodide staining was performed. HumanPASMC were seeded in a 6-well culture disk at a density of 6000 cells cm2 and incubated for 48 hours in serum-free DME, after which the medium was changed to DME with 10 FBS and antibiotics. Next, the cells were incubated for 24 hours in normal or hypoxic oxygen concentrations with or without NO donors or BPS. To measure the DNA content, the cells were harvested by trypsin and EDTA and fixed with 70 ethanol. The etha-nol was removed and the cells were incubated in PBS containing RNase (172 kunits ml) at 37 C for 30 minutes and then stained with propidium iodide (50 g ml) and dissolved in PBS for 30 minutes on ice. DNA fluorescence was measured and flow cytometric analysis was performed using an EPICS XL (Beckman Coulter, CA, USA).

Western Blot Analysis

HumanPASMC were cultured in a 6-cm dish at a density of 6000 cells cm2 and cultured for 48 hours in serum-free DME. The cells were washed twice with PBS, and then placed in DME supplemented with 10 FBS and antibiotics. The cells were then cultured in normal or hypoxic oxygen concentrations for the indicated times with or without NO donors or BPS. After incubation, the cells were harvested and resuspended in protein lysis buffer (150mM of NaCl, 20mM of Tris-HCl, 1 NP40, 10mM of EDTA, 10 glycerol, 1mM of PMSF, 10 g ml of aprotinin, 1 g ml of leupeptin, 1 g ml of gestating) and then incubated for 30 minutes on ice. After incubation, the cell lysis buffers were centrifuged at 10,000g for 15 minutes at 4 C to remove the cell fragments and the supernatants were analyzed for protein content using a DC protein assay kit. Each sample was quantified and then 25 g of protein was loaded onto each lane of a 4 - 12 Bis-Tris Nupage gel with MES SDS running buffer, according to the manufacturer's...

Symptomatic treatment

The symptomatic management of severe P-thalassaemia involves regular blood transfusion, the judicious use of splenec-tomy if hypersplenism develops, and the administration of chelating agents to attempt to deal with the problem of iron overload from regular blood transfusion. When the diagnosis of severe P-thalassaemia is suspected during the first year of life, the infant should be followed for several weeks to make sure that the haemoglobin is falling to a level at which regular transfusion will be necessary, particularly important if he or she has presented with infection that may cause the haemoglobin level to fall. It is difficult to be dogmatic about exactly when transfusions should be started, but if the infant is severely anaemic and is feeding poorly or otherwise failing to thrive, transfusion will almost certainly be necessary. The object is to maintain the pre-transfusion haemoglobin level above 9 g dL, and this usually requires transfusion every 4 weeks. Either washed or...

Radioimmunoprecipitation Extracts

1 STE. 20 mM Tris-HCl, pH 7 4, 0 15M NaCl, 1 mM ethylenediaminetetraacetic acid (EDTA), sterile filter or autoclave, store at 4 C. 3 EDTA stock solution- 250 mM EDTA, pH 8 0, sterile filter or autoclave, store at room temperature 4 IX Radioimmunoprecipitation (RIPA) IX TBS, pH 7 2, 1 (v v) Triton-X-100, 1 (w v) sodium deoxycholate, 0 1 (w v) sodium dodecyl sulfate (SDS), 1 mM EDTA, 1 (v v) aprotinin (Sigma), store at 4 C

Hydroxyquinoline derivatives

8-Hydroxyquinoline (oxine) possesses antibacterial activity against Gram-positive bacteria, but much less against Gram-negative organisms. It also has antifungal activity, although this occurs at a slower rate. Other useful compounds are depicted in Fig. 2.21b). Like oxine, clioquinol, chlorquinan-dol and halquinol have very low water solubilities, and are generally employed as applications to the skin. An interesting feature of their activity is the fact that they are chelating agents, which are active only in the presence of certain metal ions.

Activation of T Lymphocytes

Dephosphorylates NFATc, which allows it to enter the nucleus and interact with the promoter regions of cytokine genes such as the one encoding IL-2. Cyclosporin A binds cyclophilin and FK506 binds to FKBP12. Either drug protein interacts with and inhibits the activation of calcineurin. Thus, NFATc remains phosphorylated and in the cytoplasm. Reagents used to decipher this pathway included Ca2+ chelating agents, Ca2+-calmodulin-independent fragments of calci-neurin, pharmacological and peptide antagonists of calmodulin, and forms of calcineurin that are mutated so that the phosphatase activity is silenced.

Electronic apex locators

The latest generation of these devices is useful in determining the position of the apical constriction. Many recent models measure impedance rather than electrical resistance, and are less sensitive to ionic solutions within the canal. They should therefore function in the presence of NaOCl, EDTA solution, blood or pus.

Signal Amplification by in Vitro Expression of DNA Reporters Encoding Bioluminescent Proteins

Luciferases, although highly detectable, have found only limited use as labels in DNA hybridization assays because of their significant loss of activity upon conjugation to other molecules. A distinct advantage, however, of using the luciferase-coding DNA as a reporter instead ofthe enzyme itself is that inactivation problems are avoided because the synthesized luciferase remains free in solution. The cDNA of firefly luciferase (FL, MW 62 000) and Renilla luciferase (RL, MW 36 000) have been used as reporters in expression hybridization assays. Furthermore, a microtiter well-based hybridization assay that allows simultaneous determination of two target DNA sequences has been developed 27 . The target DNAs were heat-denatured and hybridized with specific capture and detection probes. The capture probes were immobilized by physical absorption in the form of conjugates with bovine serum albumin. One detection probe was biotinylated and the other was tailed with dTTP. The hybrids were...

Hydroxyapatite Chromatography

Since the matrix is inorganic and includes Ca2+ ions, this stationary phase is sensitive to the presence of chelators. Even low concentrations of chelators such as ethylene diamine tetraacetic acid (EDTA) or citrate ions can dissolve the matrix over time and should be avoided. Despite similar concerns, Tris buffers have been employed successfully at low concentrations to enable operation of the step above pH 7.0. In addition, the matrix is unstable at low pH conditions (pH 6 is recommended) but can tolerate alkaline conditions quite well. Since phosphate buffers can reduce interactions with both P and C sites, the presence of phosphate ions should be avoided in the load material or binding capacity can suffer quite drastically.

Smear layer management

When the blades of any file engage and cut dentine, a smear layer of organic and inorganic debris forms on the walls of the preparation. Whether or not to remove the smear layer or leave it intact is still debated. If the smear layer is removed then a tighter interface between the obturation materials and the dentine walls is possible. If the smear layer is left, then the root canal system is incompletely sealed and the potential for microleakage increases. EDTA in its aqueous form, flooded into well-shaped preparations has been shown to remove the inorganic component of the smear layer, and when used in conjunction with sodium hypochlorite will eliminate the smear layer.

Modeling of Interactions on IMAC

The SMA model of IEX was extended to IMAC systems 77 since this mode of chromatography is also based upon interactions of the protein with discrete binding sites on the surface and imidazole acts analogous to salt ions in IEX by binding to a single chelating site on IMAC. The key difference lies in the relatively higher affinity of imidazole for the chelation sites. Upon interaction, the protein interacts with nP sites on the stationary phase and shields aP metal ion sites.

Process Development on IMAC

Table 6.8 provides an example of operating conditions for an IMAC step. IMAC is fairly versatile in terms of its placement in a process sequence. Since, at a minimum, the load conditions include significant salt concentration to block ionic interactions both HIC and IEX eluates can be directly loaded without the need for buffer exchange (unless a citrate buffer system was used). Placement as the very first step in the process can be problematic owing to the possible presence of chelating agents in cell culture and fermentation media even though capture is where IMAC can have the greatest impact.

Of Hygromycin B Resistant LLCPK1 Cells

To remove adherent cells, wash plates 3X with PBS , add 5 mL of trypsin EDTA, and incubate at 37 C for 5-10 min The cells will round up and detach from the surface of the plate. At this stage, they can also be removed from the dish by gently moving up and down the trypsin EDTA solution using a 5-mL sterile pipet. 4 Spin cells at 400g (room temperature, aspirate trypsin EDTA solution, and wash three times with ice-cold PBS Resuspend 2 x 107 cells in 950 pL of ice-cold PBS . 7 Remove nonviable, floating cells by aspiration, wash 3X with PBS , add trypsin EDTA, and count.

Ethylendiamine tetraacetic acid

In medicine, EDTA is commonly employed as the sodium or calcium-sodium salts. Sodium calcium edetate is used in the treatment of chronic lead poisoning, and the sodium salts are used clinically to chelate calcium ions, thereby decreasing serum calcium. Also EDTA is used as a stabilizing agent in certain injections and eye-drop preparations (Russell etal., 1967). The most important early findings, in a microbiological context, were made by Repaske (1956, 1958), who showed that certain Gram-negative bacteria became sensitive to the enzyme lysozyme in the presence of EDTA in tris buffer and that EDTA alone induced lysis of P. aeruginosa. The importance of tris itself has also been recognized (Leive & Kollin, 1967 Neu, 1969), since it appears to affect the permeability of the wall of various Gram-negative bacteria, as well as the nucleotide pool and RNA, which may be degraded. A lysozyme-tris-EDTA system in the presence of sucrose is a standard technique for producing spheroplasts...

The classical pathway

The first component of complement is a complex of three protein molecules Clq, Clr and C1s. After complement-fixing antibodies have bound to their red cell antigens (EA is often used to denote the resulting erythrocyte-antibody complex), C1 binding sites are exposed on the Fc fragments. If two such sites are sufficiently close together (approximately 25-40 nm), the Cl complex is fixed through its Clq subunits. Clq is a complex molecule with six immunoglobulin binding sites. Binding of Clq activates Clr, which, in turn, cleaves the third molecule, C1s, yielding the active enzyme form of the Cl complex, which is held together by calcium. In the presence of EDTA or other chelating agents, the complex falls apart and the whole process of complement fixation will not occur.

Adjuvants and enhancers

Transport from the rectal epithelium primarily involves two transport processes paracellular and transcellular routes. As in other parts of the gut, the opening of tight junctions by absorption enhancers has been extensively investigated. Putative enhancers include enamine derivatives, salicylates, calmodulin inhibitors, surfactants, chelating agents, fatty acids and lectins. It is generally agreed that the rectum is potentially an important route

Specific recommendations for inhibitor use

PMSF and EDTA are the most frequently used inhibitors in work with animal samples. The aqueous instability of PMSF and its poor solubility are not considered to be sufficient drawbacks to limit its use. Protection against serine proteinases is frequently reinforced by the inclusion of more selective inhibitors such as benzamidine, TPCK, TLCK, leupeptin, chymo-statin and antipain (the last four will also deal with cysteine proteinases) and by the use of soybean trypsin inhibitor or aprotinin. EDTA, and less frequently 1,10 phenathroline or EGTA inhibit metalloproteinases and metal-activated proteinases. There are relatively few accounts of problems involving aspartic (b) Plant tissues. Most of the well-characterized plant proteinases are of the serine and cysteine types. In general, protective measures involving inhibitors are directed against serine proteinases through the use of PMSF in combination with another inhibitor such as chymostatin or leupeptin. The last...

Preimplantation Hlatyping

The experience of bone marrow transplantation for haemoglobinopathies presently comprises thousands of patients, showing significant progress of cure in the world's largest centre 30, 31 . The success rate is reported as 87 for Class 1 patients (with regular iron chelation therapy, who have neither hepatomegaly nor liver fibrosis), 85 for Class 2 patients (with regular irregular chelation, borderline hepatomegaly, and fibrosis), and 80 for Class 3 patients (with irregular chelation, hepatomegaly, and fibrosis) under age 17, suggesting that this may have wider implications for congenital bone marrow failures, depending primarily on the availability if HLA-matched donors.

DNA extraction from single cells

To examine the true effect of lysis conditions on the measurement of absolute copy number, different lysis conditions should be considered. Cell lysis buffers can contain EDTA, as this is a magnesium chelating agent its effect on subsequent real-time reactions should be understood. Historically individual cell lysis reactions have been kept at as small a volume as possible to maximize the final DNA concentration. DNA purification methods are not 100 efficient. When measuring the quantity of mtDNA in a sample, a percentage loss can mean any subsequent conclusions are flawed. As such, post-lysis purification is not regularly performed. Table 11.4 shows Lysis buffer without EDTA 50 mM Tris-HCl, pH8.5 1mM EDTA, pH8 0.5 Tween 20 100 g Proteinase K (B) Lysis buffer without EDTA different lysis buffers and Table 11.5 show the effect the use of each buffer has on the mtDNA copy number measured from skeletal muscle fibers taken from 20 pm cryostat sections. What can be clearly observed is that...

Neutrophilspecific antigens and antibodies

Working with granulocytes is cumbersome and typing, as well as antibody screening, should be left to specialized laboratories. The techniques used to detect neutrophil antigens and antibodies include EDTA-dependent granulocyte agglutination, immunofluorescence, cytotoxicity, opsonization, chemilumin-escence, radioactive antiglobulin tests and the use of staphy-lococcal protein A. Of these, granulocyte agglutination and immunofluorescence antiglobulin techniques are the most widely

Sources Of Nucleic Acids

Clinical specimens for DNA extraction from blood and bone marrow are normally collected in tubes containing anticoagulants such as ethylenediaminetetra-acetic acid (EDTA) or citrate. Tissue samples should generally be transported in saline to the laboratory and extracted without delay or stored frozen until processed. Tissues for nucleic acid extraction should not be placed in formalin or other fixatives because these will make subsequent extraction more difficult. If RNA is to be purified, extraction should be performed immediately, or the tissue should be frozen in liquid nitrogen to preserve RNA, which is highly labile.

Extraction Techniques

Extraction of DNA and RNA involves several steps including lysis of cells, removal of proteins and other cellular components, and purification of the nucleic acids. Because of the ubiquitous presence of nucleases, particularly RNases, some precautions are necessary to minimize degradation of DNA and RNA during extraction. These include the use of EDTA, which chelates Mg2+, an essential cofactor for many DNases, and guanidine isothiocyanate, which inactivates RNase. Solutions used for RNA extraction are usually made with water that has been treated with diethyl pyrocarbonate (DEPC), which also destroys RNases.

Preimplantation Genetic Diagnosis and Establishment of Human Embryonic Stem Cell Lines

We developed an original technique for the establishment of ES cell lines from human embryos at the morula stage, which were shown to meet all the NIH criteria. Similar to the ES cells established from human blastocysts, the morula-derived ES cells were obtained from embryos donated by patients who gave an informed consent 9 . For establishing human ES cell lines from the morula-stage embryos, zona pellucida is removed and morula placed under middle-density feeder layer. Within several days, cells outgrow and spread into the feeder layer. The primary cell disaggrega-tion is performed with EDTA, and the loose cells are transferred back to the feeder layer to proliferate. Fast proliferating colonies are isolated and propagated further. The typical human morula-derived stem cells are shown in Figure 7.1. In contrast to ES cell line derivation from morula, the establishment of the human ES cells from blastocyst involves immunosurgery, requiring the isolation and placement of the inner...

Controls for realtime PCR

Molecules per microlitre using Avogadro's number (see Chapter 2). As DNA can stick to the walls of test tubes it is advisable to use carrier DNA. We prepare our plasmid dilutions in a solution of 10 g ml lambda phage DNA in 0.1x TE (Tris-EDTA) buffer. The choice of carrier DNA should be considered carefully to ensure that there is no cross reactivity with PCR primers and probes. The range of standard concentrations should reflect the dynamic range of the assay and the values expected from patient samples in practice this is often from 106 to less than 10 molecules per microlitre. Standards should be aliquoted and stocks stored at -20 C, working aliquots should be stored at 4 C. These should be discarded when the reproducibil-ity of the lower copy number replicates deteriorates (usually between one to six months).

Tolerance Mechanisms

A complex network enables plants to control tightly the intracellular concentrations and distribution of essential heavy metals such as copper and to minimize the cytosolic concentrations of nonessential heavy metals such as cadmium. The interplay of mainly transport and chelation processes that constitutes this network results in a basic metal tolerance, the distribution, sequestration, and exclusion of potentially toxic heavy metal ions. In addition, a number of plant species show metal hypertolerance. They can grow on soil that naturally or because of human activities contains heavy metal concentrations that are growth prohibiting to most plants. These species belong to a specialized flora that has colonized Ni-rich serpentine soils or Zn- and Cd-polluted areas (13). Two principal responses to otherwise toxic heavy metal concentrations can be found, metal exclusion and metal hyper-accumulation, with the latter mainly restricted to Ni, Zn, and Se. About 400 different species...

Surface plasmon resonance biosensor analysis

Biacore Biosensor Flow Theory

Several hundred studies on macromolecular interactions using SPR biosensors have been published in a variety of fields (Rich and Myszka, 2000). Many of these studies are focused on detecting and quantitating protein-protein interactions. A typical experiment consists of covalently attaching one of the proteins to the sensor surface. A number of surfaces are commercially available for attachment including carboxymethyl dextran, which can be derivatized to give a number of different functional groups to allow for a variety of immobilization chemistries (Schuck, 1997). Other surfaces include streptavidin for capture of biotinylated molecules and a nickel chelation surface for capture of poly-histidine-tagged proteins (Rich and Myszka, 2000). Binding of soluble protein to the immobilized protein results in an SPR signal in real time that can be used to monitor association kinetics. A buffer solution lacking protein is then allowed to flow over the complex to monitor dissociation kinetics....

Stephanie L Lara Stephen P Evanko and Thomas N Wight

EDTA, 0.0005 M phenylmethylsulfonylfloride (see Note 2). a. Hyperphase solution (prepare just before spreading) Sample diluted in appropriate buffer, pH 5, 4 C 1 mM Tris-HCl, 1 mM EDTA, pH 8.5 cytochrome C stock equal parts a and b (a. 4 M Tris-HCl, 0.1 M EDTA, pH 8.5 and b. 5 mg Cytochrome C (purest grade) mL H2O) (Store at 4 C up to a year.)

Ceramic Hydroxyapatite

IgG capacity on CHT (type I, 40 m) can range from 25 to 60 mg ml, depending on the antibody and buffer composition. Achieving the maximum particularly requires control of phosphate concentration in the equilibration buffer and sample. 1 mM phosphate can reduce capacity by 15 and 5 mM can reduce it by more than half 14 . Some antibodies may support capacities 40 mg ml, even in 5 to 10 mM phosphate buffers, but the relationship between capacity and phosphate concentration persists. Neutral salts have a more modest effect 50 mM NaCl reduces capacity about 20 150 mM about 35 , making the method fairly tolerant of salt-containing samples 14 . Dynamic capacity reaches its maximum for essentially all antibodies at about pH 6.5 14 . This suggests that MES should be well suited for pH control, but it has been demonstrated to degrade CHT within as few as 10 runs (L. Cummings, personal communication, 2005). This may be a general phenomenon with nonphosphate buffers, which would suggest a...

Timothy A Fritz and Jeffrey D Esko 1 Introduction

Guanidine extraction buffer. 4.0 M guanidine-HCl, 0.2 (w v) Zwittergent 3-12, 50 mM sodium acetate (pH 6.0), 10 mM EDTA, 10 mM N-ethylmaleimide (NEM), 1 mM phenylmethylsulfonyl fluoride (PMSF), 1mg mL pepstatin A, 0.5 mg mL leupeptin. Add protease inhibitors from 200x stocks (2 M NEM in ethanol, 0.2 M PMSF in ethanol, 0.2 mg mL pepstatin A in ethanol, 0.1 mg mL leupeptin in water). Store stocks of protease inhibitors at -20 C. 2. Triton X-100 extraction buffer 20 mM Tris-HCl, pH 7.4, 0.5 (w v) Triton X-100, 0.15 M NaCl, 10 mM EDTA, 10 mM NEM, 1 mM PMSF, 1 g mL pepstatin A, 0.5 g mL leupeptin. 1. Extraction of PGs GAGs from cells and culture medium (20). Chill the cells and medium to 4 C. For most cells, adding Triton X-100 extraction buffer (2 mL 107 cells) will suffice to solubilize membrane and cell-associated PGs and GAGs. The extent of solubilization can be assessed by treating the monolayer (or residual cell pellet) with 0.5 mL 107 cells of 0.1 M NaOH at room temperature for 10...

Extraction and Purification of Aequorin

Aequorin is the best-known photoprotein and has been used widely in various applications. The first step in the extraction of aequorin from the jellyfish Aequorea (average body weight 50 g) is to cut off the circumferential margin of umbrella that contains light organs, making about 2-mm-wide strips commonly called rings . This process is important because it eliminates about 99 of unnecessary body parts that do not contain aequorin. The rings can be made efficiently by using specially made cutting devices (Johnson and Shimomura 1978 Blinks et al. 1978) or, much less efficiently, with scissors. The rings (about 0.5 g each) containing light organs are kept in cold seawater. Then, about 500 rings are shaken vigorously by hand with cold, saturated ammonium sulfate solution containing 50 mM EDTA (Johnson and Shimomura 1972) or with cold seawater (Blinks et al. 1978) to dislodge the particles of light organs from the rings. Then, the rings are removed by filtering through a net ofDacron or...

Quantification of Maximum Invasive Depth

Diagram Collagen Seeding Theory

Carefully wash the gel with 0.5 mL of PBS + 5 mM EDTA solution and collect by aspiration into the appropriate tube (see Note 12). Repeat this wash collection step two additional times. Place all solutions (i.e., washes, trypsin, and collagenase solutions) collected from each well into the same 15-mL culture tube. c. Incubate the collagen with 0.5 mL of trypsin EDTA solution at room temperature for 30 min and collect the medium and released cells by aspiration. Although this digestion does not release many cells, it does prepare the collagen for the collagenase treatment.

Introductionthe importance of mechanistic classification

The opening chapter of this volume has outlined the four mechanistic classes serine and cysteine proteases (those that form covalent enzyme complexes) and aspartic and metalloproteases (those that do not form covalent enzyme complexes). This distinction into two major mechanistic groups is of profound consequence since the strategy for inhibition is totally different for these two classes. Those enzymes of the first general class have strongly nucleophilic amino acids at their catalytic site. These are usually aligned with hydrogen bond acceptors to promote the dissociation of the nucleophile in the approach to the transition state and, thus, increase the fraction in the hyperreactive state. Design and synthesis of inhibitors of this broad class will therefore be concentrated on introduction of electrophilic groups (-C C-, -C-C( 0)-C1, etc.) that will chemically modify the nucleophile or general base. This will render the catalytic apparatus inactive and prevent the action of that...

Related To Medical Dhpt

With observations on animal tissues, Weinstein et al., (1951) suggested that toxicity arose through competition between EDTA and enzymes (and other physiologically-active complexes) in the plant, for metals essential to their activity. This will occur if the avidity of the chelating agent is greater than the metal binding capacity of proteins on the surface of cells (Albert, 1958). Toxicity can also occur in in vitro cultures. Legrand (1975) found that an optimum rate of adventitious shoot initiation occurred in endive leaf segments when only 7.5 mg l EDTA (one fifth the concentration used in MS medium) was employed. In these circumstances, higher levels of EDTA were clearly inhibitory and more than 55 mg l prevented shoot formation. Dalton et al., (1983) found that 0.3 mM EDTA (compared to the 0.1 mM in MS medium) reduced the growth rate of Ocimum cell suspensions. Tissues may be damaged by culture in media containing synthetic chelating agents where the pH approaches neutrality,...

Inhibitors of Aequorin Luminescence

EDTA and EGTA can inhibit the Ca2+-triggered luminescence of aequorin in two ways (1) when free Ca + is removed from the reaction medium by chelation, the luminescence reaction is practically stopped and (2) when the free (un-chelated) forms of these chelators directly bind with the molecules of aequorin, inhibition results (Shimomura and Shimomura 1982 Ridgway and Snow 1983). The second type of inhibition is strong in solutions of low ionic strength and in the absence of other inhibitor ions such as Mg +, but it is relatively weak in the presence of 0.1 M KCl (Shimomura and Shimomura 1984), presumably because aequorin is already inhibited by KCl. Therefore, great care must be taken if EDTA or EGTA is to be used in the calibration of the Ca + sensitivity of aequorin this is especially important in the case of low-ionic-strength calcium buffers. It should also be noted that in usual calcium buffers, the lower the Ca2+ concentration, the higher the inhibitory free chelator...

Semisynthetic Aequorins

The core cavity of the aequorin molecule can accommodate various synthetic analogues of coelenterazine in place of coelenterazine. The coelenterazine moiety in native aequorin can be replaced by a simple process. First, aequorin is luminesced by the addition of Ca +, and then the apoaequorin produced is regenerated with an analogue of coelenterazine in the presence of EDTA, 2-mercaptoethanol (or DTT), and molecular oxygen. The products are called semisynthetic aequorins and are identified with an italic prefix (see Table 1.2). Semi-synthetic aequorins can be prepared from both native aequorin and recombinant aequorin, using various synthetic analogues of coelenterazine. A large number of coelenterazine analogues were synthesized, and about 50 kinds of semisynthetic aequorins have been prepared and tested (Shimomura et al. 1988, 1989, 1990, 1993). Some semi-synthetic aequorins are significantly different from the native type of aequorin in various properties, including spectral...

Radiolabeling Studies Using 94mTc

Finally, 55Co has a half life of 18.2 hours and decays 81 by P+-emission 4 . It has been used in PET imaging as 55Co Cl2, where 55Co2+ has been used as a marker for calcium uptake in degenerating brain tissue 146-150 and complexed to molecules such as oxine and MPO (mercaptopyridine-N-oxide) for platelet labeling 151 and to EDTA for renal function assessments 152 . It has also been chelated to biomolecules including bleomycin for studies of lung cancer and brain metastases 153-155 and the MAb LS-174T 156 .

Labeling Cell Surface Proteoglycans

PBS (phosphate-buffered saline) and trypsin EDTA. PBS is 0.22- m filtered and stored at room temperature (Sigma P4417). Sterile trypsin EDTA ( 25300-062, Life Technologies) is distributed in 50-mL aliquots. Reserve stocks are stored at -20 C and working stock is stored at 4 C. 4. PBS Na2SO4 and Trypsin EDTA Na2SO4. Supplement the above solutions to 1 mM Na2SO4.

Nitric Oxide Synthesis In Plants

In soils and in aerobic environment, iron is mainly in the ferric Fe3+ form. This iron is not easily accessible for plants because it is highly insoluble at neutral or basic pH. Thereby, plants have evolved mechanisms to facilitate iron acquisition from soil which include the solubilization or chelation of iron into solution. In general, non-graminaceous plants have developed a mechanism named Strategy I based on the reduction of Fe3+ to the more soluble form Fe2+ and its uptake through specific iron transporters. The proteins involved in iron reduction and transport at the root level were already characterized in several plant species 46 . On the other hand, graminaceous plants use a mechanism termed Strategy II which is based on the chelation of Fe3+ through the release of specific Fe3+ chelators called siderophores 43,46,47 . Once iron is inside the root cell it is reduced or de-chelated. However, under aerated conditions part of the iron is oxidized and precipitates as hydroxide...

Tfp And Biofilm Development

Both colony expansion and biofilm formation by P. aeruginosa are multicellular social phenomena that involve tfp and twitching motility. An interesting correlation between the two has recently emerged. Singh et al.205 have found that iron sequestering compounds such as lactoferrin and deferoxamine inhibit the formation of P. aeruginosa biofilms in flow cells. Interestingly, it was also found that iron chelation causes enhanced colony expansion at the interstitial surface between agar and plastic in the twitching stab assay described above.205 Thus from these observations it seems that conditions that promote rapid colony expansion are inhibitory to biofilm development suggesting an inverse relationship between the two colonial behaviors. Time-lapse microscopy of cellular movements during the early stages of biofilm development in the presence of lactoferrin showed that individual cells did not settle down to form the microcolonies that are required to initiate biofilm development but...

Early Use In Plant Tissue Culture Media

In tissue cultures, omission of Mn ions from Doerschug and Miller (1967) medium reduced the number of buds initiated on lettuce cotyledons. A high level of manganese could compensate for the lack of molybdenum in the growth of excised tomato roots (and vice versa) (Hannay and Street, 1954). Natural auxin levels are thought to be reduced in the presence of Mn2+ because the activity of IAA-oxidase is increased. This is possibly due to Mn2+ or Mn-containing enzymes inactivating oxidase inhibitors, or because manganous ions are one of the cofactors for IAA oxidases in plant cells (Galston and Hillman, 1961). Manganese complexed with EDTA increased the oxidation of naturally-occurring IAA, but not the synthetic auxins NAA or 2,4-D (MacLachlan and Waygood, 1956). However, Chee (1986) has suggested that, at least in blue light, Mn2+ tends to cause the maintenance of, or increase in, IAA levels within tissues by inactivating a co-factor of IAA oxidase. When the Mn2+ level in MS medium was...

Mechanisms Of Drug Interactions

Interactions affecting drug absorption may result in changes in the rate of absorption, the extent of absorption, or a combination of both. Interactions resulting in a reduced rate of absorption are not typically clinically important for maintenance medications, as long as the total amount of drug absorbed is not affected. On the other hand, for acutely administered medications, such as sedative-hypnotics or analgesics, a reduction in the rate of absorption may cause an unacceptable delay in the onset of the drug's pharmacologic effect. The extent to which a drug is absorbed can be affected by changes in drug transport time or gastrointestinal motility, gastrointestinal pH, intestinal cytochrome P450 (CYP) enzyme and transport protein activity, and drug chelation in the gut. In general, a change in the extent of drug absorption that exceeds 20 is generally considered to be clinically significant (16).


67Ga citrate has been used as a tumor imaging agent for over 30 years 38 . It was subsequently discovered that trans-chelation of gallium to the iron-binding protein transferrin was the actual tumor imaging agent 39 . Further work demonstrated that gallium is completely bound to transferrin as soon as 15 minutes after administration of 67Ga citrate 40 . The effectiveness of this radiopharmaceutical is such that it remains in use today in the clinical diagnosis of certain types of neoplasia, lung cancer, non-Hodgkin's disease, lymphoma, malignant melanoma, and leukemia. To date, the mechanism by which gallium-transferrin enters tumors is unknown.

Galabeled Brain Imaging Agents

The work on gallium radiopharmaceuticals that can cross the blood-brain barrier (BBB) has been conducted for some time with only limited success. Species such as Ga THM2BED show low brain uptake immediately after injection, but have a very fast washout 71 . Ga EDTA has also been used to show BBB defects at the site of brain tumors and multiple sclerosis plaques 72-75 . The most promising gallium brain imaging ra-diopharmaceutical developed to date is that complexed with the small lipophilic S3N species 70 . This agent has a gradual increase in brain uptake, followed by a slow washout. This was demonstrated by a blood-to-brain ratio of 3.5 at 15 minutes after administration that increased to 5.2 after one hour.

Multiorgan Toxicity Metals

Organic mercury is very lipid soluble and is therefore well absorbed. It is toxic to the CNS and also teratogenic as in Minamata disease. The mechanism of toxicity involves binding to SH groups and inhibiting enzymes such as ATPase and uncoupling oxidative phosphorylation. It is treated with chelating agents (dimercaprol, penicillamine). Lead. Toxic metal to which there is wide exposure. Exposure is via inhalation (main source leaded petrol) and ingestion (water, old paint). Multi-organ toxicity occurs with kidneys, central and peripheral nervous system, testes, red cells, bones and gastrointestinal tract all damaged. After initial distribution into red blood cells it is eventually deposited in bone. The main biochemical effect is interference with haem synthesis at several points. Kidney toxicity may be due to lead-protein complexes and inhibition of mitochondrial function. Damage to nerves leads to peripheral neuropathy. Treatment involves use of chelating agents (EDTA).

[39 Tetanus and Botulism Neurotoxins Isolation and Assay

1 mM EDTA, 1 mM sodium azide, 1 mM benzamidine, pH 7.5 Buffer B 10 mM Sodium phosphate, pH 7.4 Buffer C 10 mM Sodium HEPES, 150 mM NaCl, pH 7.4 Buffer D 320 mM Sucrose, 4 mM sodium HEPES, pH 7.3 Buffer E 4 mM Sodium HEPES, 300 mM glycine, 0.02 w w sodium azide, pH 7.3 A chelating Superose HR 10 2 column (Pharmacia, Piscataway, NJ), connected with a Beckman (Palo Alto, CA) System Gold high-performance liquid chromatography (HPLC) apparatus, is washed at a constant flow rate of 0.5 ml min with 7.5 ml of 50 mM EDTA, 500 mM NaCl, pH 6.0, and equilibrated with 10 ml of 50 mM sodium acetate, 200 mM NaCl, pH 6.0. The column is loaded with zinc ions by flowing 7.5 ml of 100 mM zinc chloride through it. Unbound metal ions are removed with 10 ml of 50 mM sodium acetate, 200 mM NaCl, pH 6.0. Finally, the column is equilibrated with 10 mM sodium HEPES, 150 mM NaCl, pH 7.4 (buffer C). The TeNT and BoNTs (0.1-10 mg), previously dialyzed into buffer C, are loaded onto the column at room temperature,...

Analysis of Preparations and Data Intepretation

Standard trypsin-EDTA should be used for adherently growing cell lines or the recommended enzymes for dissecting cells from different tissues. Whichever protocol is used, remember that prolonged exposure to proteolytic enzymes must be avoided because it can damage cell membranes, leading to low-quality slide preparations.


Ferritin, an iron storage protein, is found in almost all biological systems 9 . It has 24 subunits surrounding an inner cavity of 60-80A diameter where the iron is sequestered as the mineral ferrihydrite (Fe2O3.nH2O - sometimes also containing phosphate). The subunits of mammalian ferritin are of two types, H (heavy) and L (light) chain which are present in varying proportions in the assembled protein. These join together forming channels into the interior cavity through which molecules can diffuse 10, 11 . The native ferrihydrite core is easily removed by reduction of the Fe(III) at low pH 4.5, and subsequent chelation and removal of the Fe(II). It is also easily remineralised by the air oxidation of Fe(II) at pH 6. The oxidation is facilitated by specific ferroxidase sites which have been identified by site directed mutagenesis studies, as E27, E62, His65, E107 and 414 , which proceed through a diferric- -peroxo intermediate 12, 13 on the pathway to the formation ofFe(III). These...


High-level blood transfusions to suppress erythropoiesis (combined with iron chelation therapy) have been used to reduce porphyrin production sufficiently to abolish the clinical symptoms. Allogeneic bone marrow transplantation has been successful.


The soluble form of the Symplectoteuthis photoprotein was isolated and purified from the granular light organs of the squid and was named symplectin (Takahashi and Isobe 1994 Fujii et al 2002). The light organs were first extracted with a pH 6 buffer containing 0.4 M KCl to remove impurities, and then symplectin was extracted from the residue with a pH 6 buffer containing 0.6 M KCl. All solutions used in the experiments contained 0.25 M sucrose, 1 mM dithiothreitol, and 1 mM EDTA. The 0.6 M KCl extract was chromatographed by size-exclusion HPLC on a TSK G3000SW column. Symplectin was eluted as two major components of oligomers, having molecular masses of200 kDa or more, and a minor component of monomer (60 kDa). All processes of extraction and purification were carried out at 4 C. Warming up a solution of symplectin, adjusted to pH 8, to room temperature causes the luminescence reaction to begin, and the light emission lasts for hours.


Aequorin is always emitting a low level of luminescence, spontaneously deteriorating by itself. Thus, the information concerning its stability is important when aequorin is used as a calcium probe. The stability of aequorin in aqueous solutions containing EDTA or EGTA varies widely by temperature, pH, concentration ofsalts, and impurities. To minimize the deterioration of aequorin, it is most important to keep the temperature as low as possible. The half-life of aequorin in 10 mM EDTA, pH 6.5, is about 7 days at 25 C. At room temperature, aequorin is most stable in solutions containing 2 M ammonium sulfate or when it is precipitated from saturated ammonium sulfate. Freeze-dried aequorin is also stable, but the process of drying always causes a loss of luminescence activity (see below). All forms of aequorin are satisfactorily stable for many years at -50 C or below, but all deteriorate rapidly at temperatures above 30-35 C. A solution of aequorin should be stored frozen whenever...


A note on freeze-dried aequorin may be appropriate here, because most commercial preparations of aequorin are sold in a dried form. The process of freeze-drying aequorin always results in some loss of luminescence activity. Therefore, aequorin should not be dried if a fully active aequorin is required. The loss is about 5 at the minimum, typically about 10 . The loss can be slightly lessened by certain additives the addition of 50-100 mM KCl and some sugar (50-100 mM) in the buffer seems to be beneficial. The buffer composition used for the freeze-drying of aequorin at the author's laboratory is as follows 100 mM KCl, 50 mM glucose, 3 mM HEPES, 3 mM Bis-Tris, and 0.05 mM EDTA, pH 7.0.

Clinical findings

In the well-transfused child, early growth and development are normal and splenomegaly is minimal. However, without adequate iron chelation therapy, there is a gradual accumulation of iron and the effects of tissue siderosis start to appear by the end of the first decade. The adolescent growth spurt fails to occur and hepatic, endocrine and cardiac complications of iron overloading produce a variety of complications, including diabetes, hypoparathyroidism, adrenal insufficiency and progressive liver failure. Secondary sexual development is delayed, or does not occur at all. The short stature and lack of sexual development may lead to serious psychological problems. By far the commonest cause of death, which usually occurs towards the end of the second or early in the third decade, is progressive cardiac damage. Ultimately, these patients die either in protracted cardiac failure or suddenly due to an acute arrhythmia, often precipitated by infection.

DNA Is Degraded

Sample incompletely treated with proteinase K. This can happen with badly stored enzyme or when too many samples are processed at one time. Thus in the absence of the high concentrations of EDTA, the tissue nucleases act to degrade DNA. This can be seen if a control digest is performed without adding enzyme or buffer and can be rectified by treating the samples with fresh cell lysis buffer. 3. Treatment of DNA sample with proteinase K in the absence of EDTA. Some samples of proteinase K retain some nuclease activity, this is inhibited when the enzyme is used in the presence of EDTA as in the cell lysis buffer.

Transfusion therapy

It is possible to eliminate most complications of SCD with the use of chronic transfusions to suppress endogenous sickle haemoglobin production. However, alloimmunization, iron overload and transmission of viruses are significant risks that limit the use of transfusions to the management of severe complications. In addition, because of the limited availability and decreased safety of blood, criteria for transfusion are more stringent in less developed countries. The high incidence of alloimmunization from minor blood group incompatibility (Rh, Kell, Duffy and Kidd) between donors and recipients can be avoided by use of phenotypically matched units. Patients on long-term transfusions develop iron overload, which requires chelation with desferrioxamine. Liver biopsies are usually necessary to measure iron burden because the serum ferritin is unreliable. As iron accumulation can be reduced or prevented by erythrocytopheresis, this technique is now preferred when venous access is...


Like Renilla luciferase, it catalyzes the oxidation of coelenterazine to yield a flash blue light of 469 nm that lasts five seconds. This flash-type light emission is accompanied by the release of CO2, has a quantum yield between 0.15 and 0.20, and requires a Ca + concentration of 0.1-10 to induce light emission 30 . To date, aequorin is one of the most extensively studied calcium-binding photoproteins. It can be regenerated by dialyzing with EDTA to remove Ca + and adding fresh coelenterazine.

Probe Development

QD bioconjugation can be achieved by several approaches, including passive adsorption, multivalent chelation, or covalent bond formation (Fig. 2). Two popular cross-linking reactions are carbodiimide-mediated amide formation, and active ester maleimide-mediated amine and sulfhydryl coupling. An advantage for the carboxylate-amine condensation method is that most proteins contain primary amine and carboxylic acid groups, and do not need any chemical modifications before QD conjugation. In contrast, free and accessible sulfhydryl groups are rare in native biomolecules and are often unstable in the presence of oxygen. Depending on the available chemical groups, other conjugation reactions can also be used. For example, Pellegrino et al. reported the use of a pre-activated amphiphilic polymer for nanoparticle solubilization (26). This polymer contains multiple anhydride units, and is highly reactive toward primary amines without addition of coupling reagents. This procedure deserves...


Sodium chloride EDTA (SE) resuspension buffer 75 mMNaCl, 25 miVf EDTA, pH 7.5, room temperature. 5. Lysis buffer (ESP) 0.5MEDTA, 1 Atlauroylsarcosine, 0.5 mg mL protease K, pH 9.5. (ESP). Make the EDTA Af-lauroylsarcosine solution and sterilize. Add protease K immediately before using. 8. 10X loading buffer 1 Bromphenol blue, 10 mM EDTA, 25 ficoll 400. 12. Tris-borate-EDTA (TBE) electrophoresis buffers 0.5XTBEfor the PFGE running buffer IX TBE for the conventional electrophoresis running buffer. 10X TBE buffer is 0.09M Tris-borate 0.002M EDTA.

Preparative PFGE

Cut away the marker lanes and test lane. These should be placed in 10 mM EDTA containing 1 mg mL ethidium bromide for 1 h, destained in 10 raM EDTA for 1 h, and then photographed (see Note 4). Take the rest of the gel and attach the grid to the underneath of the plate. With a sterile scalpel, cut 2-mm horizontal slices from the gel using the grid to guide you. It is best to do this when the gel is still attached to the plate as LMP agarose gels are very flimsy and tend to move away easily. Store the slices at 4 C in 15-mL tubes filled with 10 mM EDTA and 1 mg mL proteinase K (see Note 5).

Thalassemia HBB

The list of mutations for which we performed PGD was presented in Chapter 3. Thalassemias are among the most common single-gene disorders, requiring lifelong blood transfusion and iron chelation therapy, with the only radical treatment being HLA-compatible bone marrow transplantation, as describe in Chapters 3 and 4. As shown in those chapters, thalassemia is one of the major indications of PGD combined with preimplanta-tion HLA typing, so this provided the possibility of the establishment of ES cell lines, one of which is shown in Figure 7.5.


Some organic compounds are capable of forming complexes with metal cations, in which the metal is held with fairly tight chemical bonds. The complexes formed may be linear or ring-shaped, in which case the complex is called a chelate (from the Greek word meaning a crab's claw). Metals can be bound (or sequestered) by a chelating agent and held in solution under conditions where free ions would react with anions to form insoluble compounds, and some complexes can be more chemically reactive than the metals themselves. For example, Cu2+ complexed with amino acids is more active biologically than the free ion (Cruickshank et al., 1987). Chelating agents vary in their sequestering capacity (or avidity) according to chemical structure and their degree of ionisation, which changes with the pH of the solution. Copper is chelated by amino acids at relatively high pH, but in Despite tight bonding, there is always an equilibrium between different chelate complexes and between...


Deferiprone is rapidly absorbed, appearing in plasma within 15 min of ingestion, with a peak plasma level within 45-60 min (Table 4.3). It forms a 3 1 chelator-iron complex, which is excreted with the free drug and glucuronide derivative in urine. Only 4 of a single oral dose of the drug is excreted bound to iron, even in heavily iron-loaded patients. Its iron chelation site is inactivated by glucuronidation, the speed of which varies from patient to patient. This explains much of the individual variation in response, the area under the curve of the concentration of free drug in plasma being related to amount of iron excreted.

Peracetic acid

Figure 2.25 Chelating agents, (a) Ethylenediamine tetraacetic acid (EDTA) (b) ethylenedioxybis (ethyliminodi(aceticacid)) (EGTA) (c) acid (HDTA) (d) acid (CDTA) (c) iminodiacetic acid (IDA) (f) nitrilotriacetic acid (NTA). 13 Chelating agents This section will deal briefly with chelating agents based on EDTA. Ethylenediamine tetraacetic acid has been the subject of intensive investigation for many years, and its antibacterial activity has been reviewed by Russell (1971a), Leive (1974) and Wilkinson (1975). The chemical nature of its complexation with metals has been well considered by West (1969). The chemical structures of EDTA, ethylene-dioxybis(ethyliminodi(acetic acid)) (EGTA), acid (HDTA), transA acid (CDTA), iminodiacetic acid (IDA) and nitrilotriacetic acid (NTA) are provided in Fig. 2.25. Table 2.11 lists their chelating and antibacterial activities.

John D Sandy

If the fluid is viscous due to a high content of hyaluronan (such as is found in synovial fluid or fibroblast-conditioned medium), it should be predigested as follows Add 1 5 vol of 0.5 M ammonium acetate, 20 mM ethylenediaminetetraacetic acid (EDTA), 0.5 mM 4-(2-aminoethyl)benzenesulfonyl flouride (AEBSF), pH 6.0, and 2 TRU of streptomyces hyaluronidase and incubate at 60 C for 3 h. 5. If the samples contain chondroitin sulfate dermatan sulfate (CS DS), the dried retentates are dissolved in 50 mM sodium acetate, 50 mM Tris, 10 mM EDTA,pH 7.6, and 25 mU (per 100 g GAG) chondroitinase ABC (protease-free) is added, followed by incubation at 37 C for 1-2 h. 2. The tissue (cartilage, tendon, ligament, meniscus, aorta, etc.) is rinsed in cold PBS, chopped finely, and extracted by rocking at 4 C (15 mL of extractant per gram wet weight) for 48 h in 4 M guanidine-HCl, 10 mM MES, 50 mM sodium acetate, 5 mM EDTA, 0.1 mM AEBSF, 5 mM iodoacetic acid, 0.3 M aminohexanoic acid, 15 mM benzamidine,1...

Acute iron poisoning

Fischer R, Longo F, Nielsen P et al. (2002) Monitoring long-term efficacy of iron chelation therapy by deferiprone and desferrioxamine in patients with -thalassaemia major application of SQUID biomagnetic liver susceptometry. British Journal of Haematology 121 938-48. Hoffbrand AV, Cohen A, Hershko C (2003) Role of deferiprone in chelation therapy for transfusional iron overload. Blood 102 17-24.


The catheterization laboratory at the National Center of Cardiology in Bishkek (760 meters above sea level), Kyrgyz Republic, on 2 occasions, 1 week apart. All gave written, informed consent and were judged to be healthy on the basis of medical examination and routine hematology and biochemistry. The study was approved by the local hospital ethics committee in Bishkek and followed international guidelines for medical research on human subjects. On each occasion, a Swan-Ganz thermodilution catheter (Baxter Healthcare Ltd) was sited in the pulmonary artery via a jugular vein. Baseline measurements were made after 30 minutes rest, and then sildenafil or placebo (lactose) was given orally in a gelatin capsule with 100 mL of water. One hour later, the volunteers breathed via a mouthpiece connected to a Douglas bag containing 11 O2. Measurements of PAP, systemic blood pressure, and heart rate were repeated after 30 minutes of hypoxia. Blood samples were taken in 1 0.5 mmol L EDTA on ice...

Buffers for IMAC

Elution from IMAC resins can be effected by decreasing mobile-phase pH (which causes His residues to acquire a positive charge and cease to chelate metal ions) or by employing a mobile-phase modulator such as imidazole, which can also chelate with the metal ions. Harsher methods such as using EDTA to strip the metal ions, and thus elute protein associated with them, are not used in biopharmaceutical production, since a high concentration of metal ion would end up in the elution pool. While employing low pH elution, it should be ascertained if the ligand-Me2+ linkage is strong enough so that metal ions do not leach out. Step or linear gradient elution with imidazole is the most commonly used elution method. However, it must be recognized that imidazole itself binds quite strongly to the metal ions and hence does not function in quite the same way as salt concentration does in IEX. There can be a significant delay in breakthrough of a step or linear gradient from the column due to...

Lead poisoning

In most reported families, inheritance has followed an X-linked pattern. More than 25 different mutations of erythroid-specific ALAS2, located at Xp11.2l, have been identified. All have been single-base substitutions. Most lead to changes in protein structure, causing instability or loss of function. They are found scattered over the seven exons (out of 11) encoding the C-terminal, catalytically active part of the protein. Mutations affecting the promoter have also been shown to cause disease. Function may be rescued to a variable degree by administration of pyridoxal phosphate - the essential cofactor for ALAS2 - the best responses occurring when the mutation affects the pyri-doxal phosphate-binding domain of the enzyme. The response is better if iron overload is reduced by phlebotomy or chelation. Folic acid may benefit patients with secondary anaemia. For refractory patients, the anaemia may remain stable and, if the patient is transfusion independent, no treatment is needed....

Organic Compounds

On the other hand, enhanced HM concentrations in the shoots of mycorrhizal plants induced by some mycorrhizal fungal isolates represent optimal conditions for phytoextraction technique. In some cases, elimination of present AM fungi populations (in particular if they involve strains decreasing HM translocation to the shoots) might be recommended before phytoextraction beginning. For example, application of the fungicide benomyl detrimental to mycorrhiza was shown to significantly decrease root colonisation and simultaneously to increase Pb concentrations in plant shoots 153 . Mycorrhizal fungi may be crucial also for re-vegetation efforts after heavy metal removal as the rate of site re-vegetation may be accelerated when AM fungi are present in soil. However, little is known about mycorrhiza functioning under conditions imposed by particular metal remediation protocols. First investigations have appeared showing that the quantity and species composition of glomalean propagules and the...

Bacterial Proteases

The situation was different, however with the pathogen Pseudomonas syringae pv. syringae, which secretes an EDTA-sensitive metallopeptidase active over a broad pH range.16 This enzyme is found in the peri-plasmic space of bacterial cells, where it presumably serves several important functions critical to the pathogenicity and survival of the pathogen. In particular, it would direct the processing of the dipeptide tabtoxin, which is an inactive precursor of tabtoxine-p-lactam. This monocyclic p-lactam antibiotic is unique in that it does not affect bacterial cell wall synthesis but rather is a potent inhibitor of glutamine synthase (GS), an enzyme found in many fungal, plant and bacterial species. This toxin was also studied in the pathogen P. syringae pv. tabaci, the causal agent of wildfire of tobacco. In this case a characteristic pale halo surrounds the necrotic infection sites on leaves due to the inhibition of the host GS, an effect that can be mimicked by application of the...

Somatostatin Analogs

Octreotide is an 8-amino acid cyclic peptide that can be labeled with 68Ga using the bifunctional chelator (BFC) DTPA. However, in vitro studies have shown that trans-chelation of gallium takes place 49 . An in vitro and in vivo stable conjugate of octreotide was synthesized using the bifunctional chelator desferrioxoamine B (DFO) 49, 50 , and it was rapidly cleared from the circulation via the kidneys and showed high tumor uptake 50 .

Ga68Ge Generator

The 68Ga 68Ge generator produces 68Ga as either 68Ga ethylenediaminetetraacetic-acid ( 68Ga EDTA) or 68Ga Cl3 in 1M HCl 30 . 68Ga has been used to label blood constituents, proteins, peptides, and antibodies (see section below on Gallium). There have been a limited number of patient studies using the 68Ga 68Ge generator. The most common use of 68Ga is in the form of 68Ga citrate, which upon administration produces 68Ga transferrin. This approach has been used to measure pulmonary transcapillary escape rate in various disease states 31-35 .

Chemistry of Gallium

Gallium is a group 13 element and exists most commonly in the +3 oxidation state. While lower oxidation states have been observed, all relevant radiopharma-ceuticals occur in this oxidation state. Similar to other group 13 elements (B, Al, and In), Ga3+ is classified as a hard acid , bonding strongly to highly ionic, non-po-larizable Lewis bases. As a result, gallium chemistry is dominated by ligands containing oxygen and nitrogen donor atoms 36 . There are two requirements for using gallium complexes as radiopharmaceuticals. The first is that gallium complexes must resist hydrolysis at physiological pH. Ga(OH)3, the primary product formed at physiological pH, is insoluble. It is not until the pH is increased above 9.6 that the soluble species Ga(OH)4 - is formed. The second concern is that Ga3+ has an electronic configuration of 3d10, and this is similar to that of high spin Fe3+, which has a half-filled 3d shell. As a result, their ionic radii, ionization potential, and coordination...


In the heart, kidneys, thyroid, spleen and retina. The serum iron is low. The total iron-binding capacity of transferrin (TIBC) is normal and ferritin is normal or raised. Interestingly, there is evidence that iron chelation with DFX may decrease brain iron stores and halt the progression of the neurological degeneration.


Diamond-Blackfan, Fanconi, sickle cell, sideroblastic anaemia or acquired disorders, especially myelodysplasia, myelofibrosis red cell aplasia or aplastic anaemia, may require iron chelation therapy. In elderly patients with acquired, transfusion-dependent, refractory anaemias, the prognosis of the underlying haematological disease may not justify the inconvenience of s.c. DFX therapy. In children, tissue damage from iron may be present from very early life regular iron chelation should begin in thalassaemia major after transfusion of about 12 units of blood or when the serum ferritin exceeds 1000 ig L. In young children, treatment should be started at 20 mg kg to prevent tissue damage due to iron without causing toxicity due to excess DFX. A local anaesthetic cream (e.g. EMLA) reduces pain from the needle insertion. In patients unable to comply with s.c. DFX or those with iron-induced cardiomyopathy, continuous intravenous (i.v.) DFX may be given via an indwelling catheter (e.g....

Protein A Leaching

Protein A is known to cause immunogenic responses in humans and has been proven toxic in a number of clinical trials 68 . One should pay special attention during development of the polishing steps to reduce leached Protein A to safe and acceptable levels. Leaching can occur by three different pathways breakdown of the support matrix, breakdown of the immobilization linkage, and proteolytic cleavage of the interdomain sequences of Protein A 15 . To avoid the first two, it is recommended to select a resin from an established manufacturer with a history of good ligand stability. In industrial processes, Protein A leaching is primarily a result of proteolytic degradation due to proteases that can be present in the cell culture fluid. Thus, addition of chelators such as EDTA to cell culture harvest (to inhibit metallo-proteases) or holding the cell culture load at lower temperatures can also help to reduce Protein A leaching. Storage conditions for resin storage can also have an influence...

Enzyme Preparations

Microsomes are prepared from tissues by first suspending 2-5 g of tissue in 4 volumes of 0.25 M sucrose containing protease inhibitors (1 mM phenylmethylsulfonylfluoride, 10 mM EDTA, 1 mM N-ethyl maleimide, 0.5 mg mL leupeptin and 0.1 mg mL pepstatin) in case there might be slight protease modifications of the enzymes (see Note 10), and homogenizing 3 to 5 times with a Polytron at the maximum speed for 1 min each. The homogenate is centrifuged at 12,000g (occasionally 10,000g or 20,000g) in a fixed-angle rotor for 20 min, and the supernatant fluid is then centrifuged at 105,000g for 1 h. The pellets are suspended in 0.25 M sucrose and recentrifuged at 105,000g for 1 h to wash the resulting microsomal fraction (see Note 11). Greatest experience has been with microsomal preparations from chick embryo epiphyseal cartilage (see Note 12) and mouse mastocytomas.