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PubMed2006

[Determination of lead in water samples by graphite furnace atomic absorption spectrometry after cloud point extraction with dithizone].

Cloud point extraction was used for the preconcentration of lead after the formation of a complex with dithizone in the presence of surfactant Triton X-114, and then the lead was determined by graphite furnace atomic absorption spectrometry. The conditions affecting the separation and detection process were optimized. Separation of the two phases was accomplished by centrifugation for 15 min at 4 000 rpm. Upon cooling in an ice-bath, the surfactant-rich phase became viscous. The aqueous phase could then be separated by inverting the tubes. Later, a solution of methanol containing 0.1 mol x L(-1) of HNO3 was added to the surfactant-rich phase up to 0.5 mL. The samples were determined by graphite furnace atomic absorption spectrometry with NH4H2PO4 and Mg(NO3)2 as a chemical modifier. At pH 8.0, the preconcentration of only 10 mL sample in the presence of 0.05% Triton X-114 and 20 micromol x L(-1) dithizone permitted the detection of 0.089 microg x L(-1) lead. The enhancement factors were 19.1 times for lead. The calibration graph using the preconcentration system for lead was linear with a correlation coefficient of 0.998 from levels near the detection limits up to at least 30 microg x L(-1). The regression equation was A = 0.026 1c (microg x L(-1)) + 0.010 6. The proposed method has been applied to the determination of lead in water samples.

Dithizone↗
PubMed1981

[Preconcentration of copper (II) and mercury (II) using dithizone and carbon powder followed by neutron activation analysis (author's transl)].

A combined method of dithizone-extraction and carbon powder column adsorption was applied to concentrate trace amounts of copper (II) and mercury (II) in natural water samples before neutron activation analysis. The sample solution was adjusted to pH 1.0 with nitric acid, an aliquot of which as taken in a 500 cm3 separating funnel and then 5.0 cm3 of 0.01% dithizone-benzene and 25 cm3 of n-hexane wee added. The mixture was shaken for 10 min and stood for 30 min. After the aqueous phase was discarded, another aliquot of the sample solution was added. The above procedure was repeated until the treatment of the sample solution (1.00 dm3) was completed. The organic phase was then flown through the column (6mm phi x 50 mmh) containing carbon powder, and the resulting column was dried. The monitor containing 10 micrograms of mercury or copper was also prepared according to the above procedure. The samples and monitors were irradiated together in a pneumatic tube of JRR-3. After cooling, copper and mercury were determined by gamma-spectrometry using 64Cu, 197Hg, respectively. The recovery of trace metal ions obtained by this method was more than 99%, and the present method was found to be applicable to the preconcentration of copper (II) and mercury (II) in natural water samples.

Activation Analysis↗
PubMedDate not supplied

[The cytochemical dithizone reaction of the blood granulocytes in zinc-deficient states].

The blood granulocyte zinc content is liable to be reduced in hepatocirrhosis, chronic glomerulonephritis presenting with nephrotic syndrome, chronic enteritis, diabetes mellitus, and in frequent and excessive sweating, as evidence by a study conducted with the aid of a cytochemical dithizone test. A short discussion is given on potentials for application of the cytochemical dithizone test as a diagnostic aid to the study of the blood granulocyte zinc content in zinc deficiency states.

Chronic Disease↗
PubMed1989

Evidence from dithizone and selenium zinc histochemistry that perivascular mossy fiber boutons stain preferentially "in vivo".

This paper describes a perivascular staining pattern that is obtained when dithizone or sodium selenite are used to label zinc intravitally. Our observations indicate that the perivascular staining is a result of zinc labeling in mossy fiber boutons adjacent to capillaries and suggest that there might be a special blood brain barrier in the mossy fiber regions.

Animals↗
PubMed1977

Serum mineral changes in dithizone-induced diabetes before and after insulin treatment.

In this study, diabetes was induced by intravenous injection of dithizone. In dithizonised diabetic animals, the levels of serum zinc, iron, and potassium were found to be higher than normal, while those of serum calcium and sodium were lower. Copper and magnesium levels were unchanged. After treatment with insulin, most of these serum levels approached the normal, except for serum potassium and magnesium.

Animals↗
PubMed2004

Speciation analysis of mercury in water samples by cold vapor atomic absorption spectrometry after preconcentration with dithizone immobilized on microcrystalline naphthalene.

Trace amounts of inorganic mercury (Hg(2+)) and methylmercury cations (MeHg(2+)) were adsorbed quantitatively from acidic aqueous solution onto a column packed with immobilized dithizone on microcrystalline naphthalene. The trapped mercury was eluted with 10 ml of 7 mol L(-1) hydrochloric acid solution. The Hg(2+) was then directly reduced with tin (II) chloride, and volatilized mercury was determined by cold vapor atomic absorption spectrometry (CVAAS). Total mercury (Hgt) was determined after decomposition of MeHg(+) into Hg(2+). Hg(2+) and MeHg(+) cations were completely recovered from the water with a preconcentration factor of 200. The relative standard deviation obtained for eight replicate determinations at a concentration of 0.3 microg L(-1 )was 1.8%. The procedure was applied to analysis of water samples, and the accuracy was assessed via recovery experiment.

Cold Temperature↗
PubMed1985

Colorimetric micromethod for the determination of protein in solutions with silver ions and dithizone.

A method of determination of protein based on the measurement of complexed Ag+ and AgCl absorbed on the macromolecules is described. This reaction is carried out in the presence of chloride ions and detergents (Triton X-100 or SDS) in alkaline solution. The silver ions are detected with dithizone. With this method it is possible to estimate 0.1 microgram bovine serum albumin in 0.5 ml sample with a coefficient of variation of 16%, and 1.5 micrograms/sample with a coefficient of variation of 3.6%. The method is simple, rapid, inexpensive, and very sensitive.

Azo Compounds↗
PubMed2003

Dithizone derivatives as sensitive water soluble chromogenic reagents for the ion chromatographic determination of inorganic and organo-mercury in aqueous matrices.

Water-soluble sulfonate and the novel carboxylate analogues of dithizone, combined with ion interaction chromatography on a Dionex Acclaim 120 C18 silica column (250 x 4.6 mm id) with an eluent consisting of 10 mM tetrabutylammonium bromide and 60:40 methanol:water, have been developed as highly sensitive chromogenic ligands for the quantitative isocratic determination of inorganic and organo-mercury compounds in aqueous matrices in under 12 min. Using an optimised post column reagent system containing 0.65 mM dye, 0.5% Triton X-100 and 50 mM sodium hydroxide, good linearity (0-7.5 mg L(-1) R2 > 0.999), reproducibility using peak area measurements (RSD 0.69-1.38%, n = 8), and limits of detection (4-12 microg L(-1)) were achieved for methyl mercury, inorganic mercury and phenyl mercury.

Chelating Agents↗
PubMed2006

Determination of Pb(II) with a dithizone-modified carbon paste electrode.

A dithizone (DTZ) modified carbon paste electrode was developed for the sensitive and selective determination of Pb(II) using differential pulse anodic stripping voltammetry as well in batch as in FIA system. The analysis procedure is based on an open circuit accumulation step in a stirred sample solution. This was followed by a medium exchange to a clean solution and subsequently by a proper anodic stripping. The analytical performance was evaluated with respect to the quantity of modifier in the paste, accumulation time, background electrolyte, Pb(II) concentration and other variables. When the accumulation time applied was 5 minutes, linear calibration graphs were obtained in the concentration range 1 x 10(-7)-1 x 10(-5) M and 8 x 10(-8)-5 x 10(-6) M for batch and Flow Injection Analysis (FIA), respectively. The detection limits found were 8.65 x 10(-8) M in batch and 4.45 x 10(-8) M in FIA. A convenient and rapid renewal of electrode surface allows the use of a single modified electrode surface in multiple analytical determinations. Several coexisting metals ions such as Cd(II), Hg(II), Cu(II) and Zn(II) had no interference on the determination of Pb(II). The proposed method was applied in the determination of lead in soils located in the vicinity of metallurgic transformation industry. The results obtained were in accordance to the ones supplied by Atomic Absorption Spectroscopy (AAS).

Calibration↗
PubMed1994

Deleterious effect of dithizone-DMSO staining on insulin secretion in rat and human pancreatic islets.

Dithizone (DTZ) is a selective stain for pancreatic islets which facilitates their identification, being of special interest in human islet isolation assessment. Nevertheless, there are few studies concerning its potential toxic effects on islet function. In our study, we have evaluated the effects of DTZ (dissolved in dimethyl sulfoxide [DMSO] 1% w/v) at three different concentrations (2, 10, and 100 micrograms/ml) on insulin response to glucose in human and rat islets. Likewise, we studied the effect of incubation time, in the presence of DTZ at the above-mentioned concentrations, on insulin release. Only when DTZ was employed at low concentrations and for a short period of incubation (10 min) was there no impairment of pancreatic islet function. Moreover, even at this low concentration, DTZ became deleterious for islet function when the incubation period with the dye was prolonged for 30 min. Culture (24 h) of previously stained islets produced a partial recovery of insulin response. In conclusion, our findings indicate (a) DTZ should not be employed to collect islets for functional studies because of its deleterious effect on beta-cell function, (b) DTZ's deleterious effects on beta-cell function should be considered if this dye is used to purify islets by fluorescence-activated cell sorting for transplantation.

Animals↗
PubMedDate not supplied

Staining and in vitro toxicity of dithizone with canine, porcine, and bovine islets.

Dithizone (DTZ) is a recognized diabetogenic agent in vivo, and a supravital stain commonly used for identification of islets to be used for transplantation. In the present studies, we compared DTZ staining of freshly isolated and cultured canine, bovine, and porcine islets, and the effect of DTZ on the function and viability of islets. Incubation with DTZ resulted in staining of canine and porcine islets, but no discernible staining with bovine islets. Insulin content of porcine, canine, and bovine islet was 2.0 +/- 0.2, 2.2 +/- 0.3, and 1.9 +/- 0.2 mU/EIN, indicating a lack of correspondence of DTZ staining and insulin content. Seven days of culture with canine islets resulted in > or = 50% reduction of DTZ stained cells. Exposure to DTZ at 50 micrograms/mL resulted in a maximal number of stained cells in preparations of purified islets (80-85%; counted after dispersion), a lower percentage of cells stained faintly at 20 micrograms/mL (50-55%), with no discernible staining at 10 micrograms/mL. Prolonged exposure of islets (4-48 h) to 20 micrograms/mL DTZ led to reduced insulin secretion and islet cell death. Incubation of canine or porcine islets with 100 micrograms/mL of DTZ for 0.5 h resulted in a dramatic loss of viability and diminished insulin secretory function, which was not reversed with continued culture. The concentration dependence of toxic effects paralleled the concentration dependence of cellular staining. The minimally effective staining concentration (20 micrograms/mL) also resulted in a loss of viability. An additional assessment of DTZ toxicity was made using the RIN-38 beta-cell line, which shows no discernible staining with DTZ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Identification of insulin-producing cells derived from embryonic stem cells by zinc-chelating dithizone.

BACKGROUND AND AIMS: Embryonic stem (ES) cells have a pluripotent ability to differentiate into a variety of cell lineages in vitro. We have recently identified the emergence of cellular clusters within differentiated ES cell cultures by staining with dithizone (DTZ). DTZ is a zinc-chelating agent known to selectively stain pancreatic beta cells because of their high zinc content. The aim of the present study was to investigate the characteristics of DTZ-stained cellular clusters originating from ES cells. METHODS: Embryoid bodies (EBs), formed by a 5-day hanging drop culture of ES cells, were allowed to form outgrowths in the culture. The outgrowths were incubated in DTZ solution (final concentration, 100 microg/ml ) for 15 minutes before being examined microscopically. The gene expression of endocrine pancreatic markers was also analyzed by reverse transcriptase-polymerase chain reaction. In addition, insulin production was examined immunohistochemically, and its secretion was examined using enzyme-linked immunosorbent assay. RESULTS: DTZ-stained cellular clusters appeared after approximately 16 days in the EB culture and became more apparent by day 23. They were found to be immunoreactive to insulin and expressed pancreatic-duodenal homeobox 1 (PDX1), proinsulin 1, proinsulin 2, glucagon, pancreatic polypeptide, glucose transporter-2 (GLUT2), and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) mRNA. They were also able to secrete detectable amounts of insulin. CONCLUSIONS: ES cell-derived DTZ-positive cellular clusters possess characteristics of the endocrine pancreas, including insulin secretion. Further, DTZ staining is a useful method for the identification of differentiated pancreatic islets developed from EBs in vitro.

Animals↗
PubMed1998

Monitoring of rat islet allografts with dithizone after induction of donor specific transplant tolerance by intrathymic administration of soluble alloantigens.

Transplantation of whole pancreas or pancreatic islets remains a promising approach to treatment of diabetes mellitus. Since there is no efficient method presently known for in vivo detection of pancreatic islet rejection, we have utilized dithizone [DTZ] to monitor the survival of transplanted islet allografts following the induction of tolerance by a new strategy of deliberate introduction of donor antigens into the adult thymus. In this study, we examined the morphology of islet allografts in vivo and in vitro following pretreatment with intrathymic (IT) inoculation of 2 mg soluble Ag obtained from 3M KCl extracts of resting T-cells with or without ALS immunosuppression in the WF-to-Lewis combination. Fresh isolated rat islets stained pink 3-5 minutes following exposure to medium containing 0.12 mM DTZ solution in DMSO. Intravenous (i.v.) injection of DTZ solution into unmodified recipients of islet allografts that had rejected their grafts showed massive degranulation of islets which did not stain pink with DTZ. This was confirmed by microscopic finding of fibrosis and lymphocytic infiltration. In contrast, i.v. injection of DTZ solution into long-term recipients of islet allografts at 50, 100, and 150 days after transplantation showed viable islet cells which stained crimson red with DTZ and the findings were confirmed with microscopic sections. This study demonstrates that DTZ is an effective means of in vivo and in vitro identification of transplanted pancreatic islets and suggests that this strategy may have potential clinical application in the diagnosis of the pancreatic islet rejection.

Animals↗
PubMedDate not supplied

[The dynamics of the Zn content in the pancreatic islets of rabbits after the administration of the diabetogenic agent dithizone].

The dynamics of changes of the Zn content in the pancreatic islets of rabbits after dithizon injection was studied. The amount of this metal in the islets reduced due to destruction of the cells and under the effect of high blood plasma glucose concentration. The insulin producing cells were devoid of zinc in diabetes of long duration with high hyperglycemia.

Aminoquinolines↗
PubMedDate not supplied

[Effect of fasting, glucose load and dithizone injections on the zinc content in pancreatic islets of the rabbit].

The content of zinc in the pancreatic islets was increased in fasting animals and reduced after a glucose load and dithizone injection. A negative correlation between the blood sugar level and the zinc content in the pancreatic islets was encountered. A changed content of zinc in the islet cells may serve as a sensitive indicator of changes in the functional condition of the pancreatic insular apparatus.

Animals↗
PubMedDate not supplied

[Changes in the myocardium during the early stages of dithizone diabetes development].

Sorption capacity, the content of catecholamines, cytochrome C, the activity of cytochromoxidase, of some tricarbonic acids cycle enzymes were studied in the myocardium of rabbits with dithizone diabetes of moderate severity. The detected electrocardiographic changes, hypoxia, disturbances of the hormone-mediator-enzymatic metabolism an increased affinity to the myocardial cell stain at the early periods of diabetes mellitus development permitted to regard cardiovascular affections in diabetes mellitus as a manifestation, not as a complication of the disease.

Animals↗
PubMed1983

[Damaging action of dithizone on insulin-releasing cells].

Alterative action of dithizone was investigated in the experiments on various species of animals (fish, frogs, pigeons, mice, guinea pigs, golden hamsters, rats, rabbits, cats and dogs). The data received support the previously advanced suggestion that unsaturated (electrophilic) zinc complex formation is the basic mechanism of the alterative chelant's action.

Animals↗