The sharing of injecting paraphernalia among illicit drug users.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
S G Jones
Publications and source records attributed to S G Jones.
Singlet oxygen yields of furocoumarins and related molecules--the effect of excitation wavelength.
Singlet oxygen yields (phi delta) were compared for a wide range of furocoumarins and related compounds using excitation wavelengths of 313, 334 and 365 nm. The phi delta values ranged from 0.02 or less to 0.4, but no wavelength dependence was detected for any of the compounds studied.
Furocoumarins↗
A comparative study of the influence of vicinal dithiols and a dithiocarbamate on the biliary excretion of cadmium in rat.
The effect of two vicinal dithiols, 2,3-dimercaptopropan-1-ol (BAL) and N-(2,3-dimercaptopropyl)phthalamidic acid (DMPA), and a dithiocarbamate, sodium N-(4-methoxybenzyl)-D-glucamine dithiocarbamate (MeOBGDTC), on the biliary excretion of cadmium was examined in rats. Tissue cadmium levels were also determined following the measurements of biliary excretion of cadmium. At 30 min after the injection of CdCl2.2.5H2O (1 mg/kg, iv) each rat was given 400 mumol/kg ip of one of the compounds, BAL, DMPA or MeOBGDTC. While all the compounds increased the biliary excretion of cadmium, the most effective was MeOBGDTC, whose administration resulted in a 580% increase in biliary cadmium content. The effectiveness of the MeOBGDTC may be due to the presence of both nonpolar and nonionizing polar groups attached to nitrogen. MeOBGDTC was able to mobilize cadmium to the bile even after the occurrence of the synthesis of metallothionein and the incorporation of the cadmium into it. An attempt was also made to determine the chemical nature of the Cd-MeOBGDTC complex present in the bile by comparing a newly synthesized authentic sample of Cd(MeOBGDTC)2 complex with the hot dioxane extract of the freeze-dried bile samples using thin-layer chromatography and proton NMR. The results suggested that cadmium excreted in the bile in part, is complexed to MeOBGDTC and glutathione.
Animals↗
Thermographic assessment of burns using a nonpermeable membrane as wound covering.
Infrared thermography is a useful technique for the investigation of disorders which affect skin blood flow. The damage to skin blood vessels caused by thermal injury is a major determinant of the capacity of the wound to heal. Thermographic assessment of this damage has been found to correlate with the healing time of burn wounds. However, the application of thermography to the assessment of burns for early surgery has been limited because of the difficulties involved in correcting for cooling artefacts resulting from the effect of evaporative water loss (EWL) at the wound surface. A water impermeable polyvinylchloride film (sold in the USA as Saran Wrap, in Australia as Glad Wrap and in the UK as Clingfilm (CF)) was investigated as a wound covering to avoid this cooling effect. It was found that the CF abolished the cooling effect of EWL and did not significantly interfere with the measurement of surface temperature. This material provides a solution to the problems of thermographic examination of wounds such as burns where damage to the skin surface allows exudation or EWL to occur.
Adolescent↗
Dithiocarbamates of improved efficacy for the mobilization of retained cadmium from renal and hepatic deposits.
The preparation and properties of two novel cadmium-mobilizing dithiocarbamates namely, sodium N-(4-methylbenzyl)-and sodium N-(4-methoxybenzyl)-4-O-(beta-D-galactopyranosyl)-D-glucamine-N-carbo dithioates derived from alpha-lactose and substituted benzylamines are described. These compounds are more effective than previously prepared compounds of this type for the mobilization of cadmium from its aged deposits in both the liver and the kidneys. An examination of the structural features of the more effective compounds for the mobilization of cadmium from its aged deposits reveals that the combination of a high molecular weight with a suitable amphipathic structure in which the polar and non-polar groups are in an appropriate balance are key features. A histopathological evaluation of the animals from which cadmium is removed by these compounds indicates no variations from the normal for the kidney and no evidence of hepatic damage resulting from the removal of the cadmium. On the basis of the trends observed in cadmium mobilizing efficacy, there are grounds for suspecting that agents which are significantly more effective than any prepared so far, should also be accessible.
Animals↗
Intracellular cadmium mobilization sequelae.
The consequences of the mobilization of aged intracellular cadmium from its in vivo deposits in mice by chelating agents were examined. The chelating agents used were BAL, sodium N-benzyl-D-glucamine dithiocarbamate (NaB), Diisopropyl meso-2,3-dimercaptosuccinate(Di-PDMS) and sodium N-(4-methoxybenzyl)-D-glucamine dithiocarbamate(4-Me0), all previously shown capable of causing statistically significant decreases in either renal or hepatic cadmium burdens in rodents. They were given at a level of 400 mumol/kg (i.p.) daily for 10 days to mice previously loaded with a total of 10 mg CdCl2.2.5 H2O/kg. Under these conditions a significant decrease in the renal cadmium level occurred following treatment with BAL, NaB, and 4-MeO; hepatic cadmium levels decreased significantly following treatment with NaB and 4-MeO. Pathological examination of the kidneys, liver, and testes in these animals showed that chelate mobilization of the cadmium produced no noticeable changes in the histopathology of these organs in comparison with that observed for the animals which had been given only cadmium and had undergone no chelate treatment. The results suggest that the mobilization of such aged cadmium from in vivo deposits need not result in any deleterious changes in the kidneys, liver or testes.
Animals↗
Selective removal of cadmium from aged hepatic and renal deposits: N-substituted talooctamine dithiocarbamates as cadmium mobilizing agents.
The preparation and examination of three dithiocarbamates derived from N-substituted D-gluco-L-talooctamine reveals that the 4-methoxybenzyl derivative (MeOBGD) is superior to any previously prepared dithiocarbamates as an agent for the mobilization of aged intracellular hepatic cadmium deposits from mice. All of these compounds are also quite effective in reducing whole body burdens of cadmium. The use of these compounds does not result in any increase in the cadmium content of the brain. The selection of these chelating agents for synthesis was suggested by an analysis of the log dose-response curves for the mobilization of renal cadmium by previously studied dithiocarbamates. This revealed that the slope of the percentage renal cadmium mobilized vs the log dosage curve is determined to a considerable extent by the sum of the Hansch pi parameters for the substituents, while the intercept is largely determined by the molecular weight of the compound. The implication of such a correlation is that the ability of a chelating agent to remove cadmium from its aged deposits is determined to some extent by its molecular weight, provided the polarity of the overall molecule is appropriate.
Aging↗
Thermographic assessment of hand burns.
Twenty-three patients with 32 burned hands were studied thermographically within 48 h of injury to investigate the potential value of thermography in the assessment of the depth of hand burns. Superficial and deep partial thickness burns were treated conservatively, with excision and grafting of those which had not healed by 2-3 weeks after injury. This delayed surgery group and the healed group were retrospectively analysed to determine the predictive value of the initial clinical and thermographic assessments of the depth of the burns. Full skin thickness burns were excised and grafted within 5 days and were not included in the study. Initial thermographic assessment correctly predicted the outcome (whether healed or excised and grafted) in 33 of 36 burns. This relationship was highly significant. Initial clinical assessment of depth had no significant relationship with the time taken to heal. Thermography may help in the selection of patients who might benefit from early surgery.
Adult↗
Structural factors in the in vivo chelate mobilization of aged cadmium deposits.
The role of structural factors in determining the relative efficacy of dithiocarbamates as chelating agents for the in vivo mobilization of aged cadmium deposits is examined for 23 newly synthesized compounds of this type. The critical feature in determining the efficacy of the compounds in mobilizing intracellular cadmium is the balance between hydrophobic and hydrophilic groups. This balance also governs the other properties of these compounds such as the organ specificity of action and the relative propensity to carry cadmium to the brain. The transport of cadmium to the brain by dithiocarbamate can be greatly reduced by the incorporation of appropriate hydrophilic groups that prevent the formation of lipid-soluble cadmium complexes that pass readily into the brain. If the chelating agents carry an additional ionic charge, their ability to pass through cellular membranes and react with intracellular deposits of cadmium is significantly reduced, with other structural factors being equal. The structural features that optimize mobilization of cadmium from the kidney do not appear to be identical with those that optimize its mobilization from the liver. The correlation of cadmiummobilizing properties of these chelating agents with the sum of the Hansch pi constants for the parts of the molecular structures other than the dithiocarbamate grouping (sigma pi) is reasonably good for the removal of renal cadmium by derivatives of D-glucamine and D-xylamine. Another aspect of the molecular structure that appears to play a role is the presence of uncharged polar groups having the ability to form hydrogen bonds. The relevance of these factors in designing chelating agents to enhance the excretion of other toxic metals from their intracellular sites is discussed.
Animals↗
Effect of chelating agent structure on the mobilization of cadmium from intracellular deposits.
An examination of the efficacy of several structural types of chelating agents in the removal of cadmium from its intracellular deposits in mouse liver and kidneys reveals that of the structural types examined, only dithiocarbamates and a vicinal dithiol were able to mobilize cadmium from such intracellular sites. Esters of L-cysteine, a macrocyclic thioether, and a disulfide of a dithiocarbamate were unable to cause any appreciable decrease in either renal or hepatic cadmium levels. Charged groups such as carboxylic acid groups reduce the efficacy as well as the toxicity of the structural types that can otherwise mobilize such cadmium. It was also found that the administration of a cadmium-binding polymer ip leads to only a very slight net excretion of cadmium, while the po administration of this polymer leads to no net additional cadmium excretion. Of the compounds newly reported here, some are approximately equal in cadmium-mobilizing efficacy to the most effective of previously reported compounds.
Animals↗
Dependence on chelating agent properties of nephrotoxicity and testicular damage in male mice during cadmium decorporation.
An examination of the histopathological appearance of the kidneys of mice treated with cadmium chloride (s.c.) and simultaneously given 1 of 3 chelating agents (i.p.) reveals that the extent of nephrotoxicity is greatest when L-cysteine is the chelating agent. When either of 2 dithiocarbamates capable of mobilizing cadmium from its intracellular deposits, i.e. sodium N-methyl-D-glucamine dithiocarbamate (NaG) or sodium N-benzyl-D-glucamine dithiocarbamate (NaB) is used as the chelating agent, no morphological renal damage was evident. Under these same conditions the testes of the mice were protected to the extent of 95% by both of the dithiocarbamates, whereas the protection afforded by the L-cysteine was only about 50%. One factor governing the extent of nephrotoxicity appears to be the stability of the cadmium complexes which are formed and the manner in which this affects their behavior in vivo. Complexes which are preferentially excreted in the bile, cause little or no renal damage.
Acute Kidney Injury↗
N-alkyl-N-dithiocarboxy-D-glucamine analogs as cadmium antagonists: synthesis and evaluation of the n-propyl, n-butyl, and n-amyl derivatives.
N-(n-Propyl)-, N-(n-butyl)-, and N-(n-amyl)-N-dithiocarboxy-D-glucamine were newly synthesized by (a) addition of each n-alkylamine to glucose, (b) high-pressure catalytic reduction of each glucosamine thus formed to the corresponding glucamine, and (c) reaction of the resultant secondary amines with CS2 to form the dithiocarboxy derivatives. Each compound was evaluated as an antagonist of acute cadmium (Cd) toxicity and as a complexing agent for intracellular metallothionein-bound Cd (Cd-MT) in mice. N-Benzyl-N-dithiocarboxy-D-glucamine (BDCG) was used as a positive control compound. Each congener afforded partial or complete protection against the lethal effects of 10.0 mg/kg CdCl2.2.5 H2O, and retarded accumulation of Cd in livers and kidneys when given 2 h after the acutely toxic dose of Cd. Each derivative was also effective in mobilizing Cd from MT-bound sites in livers and kidneys of mice which had received a sub-lethal dose of CdCl2 along with 109CdCl2 2 weeks earlier. Excretion of mobilized Cd was almost exclusively by the fecal route. Potency of the analogs, as well as the octanol/aqueous partition coefficients, increased with the overall length of the N-(n-alkyl) carbon chain. Each compound readily complexed Cd from partially purified Cd-MT in vitro. Serum Cd from mice treated with BDCG was associated principally with proteins of high molecular weight.
Animals↗
Meso-2,3-dimercaptosuccinic acid and sodium N-benzyl-N-dithiocarboxy-D-glucamine as antagonists for cadmium intoxication.
Orally administered meso-2,3-dimercaptosuccinic acid (DMSA) is an effective antagonist for acute oral cadmium chloride (1 mmol/kg) intoxication in mice when administered up to 8 h after cadmium ingestion. Administration of sodium N-benzyl-N-dithiocarboxy-D-glucamine (NaB) i.p. along with DMSA p.o. resulted in kidney and liver cadmium levels only marginally smaller than those obtained with DMSA alone. Both chelation treatment regimens permitted survival of 80% or more of the animals, in comparison to a survival rate of 40-50% in untreated animals. Intraperitoneally administered NaB by itself is a very effective antagonist for cadmium chloride administered intraperitoneally in either acute or chronic cadmium intoxication. A dose-response study was made of the mobilization of cadmium from the liver and kidney of cadmium-loaded mice by NaB; this showed that NaB is one of the most effective cadmium mobilizing agents developed to date. We have also confirmed the earlier report of Kojima and his co-workers of the ability of NaB to remove cadmium from animals which have been treated with cadmium over an extended period of time. NaB causes a very large increase in the biliary excretion of cadmium. Nuclear magnetic resonance (NMR) spectra of 113Cd in bile from treated animals and model solutions indicates that such cadmium is undergoing rapid ligand exchange.
Administration, Oral↗
Mobilization of aged in vivo cadmium deposits by diethyl dimercaptosuccinate.
Diethyl dimercaptosuccinate (DEDMS) was prepared and found to be capable of mobilizing cadmium from mice one month after they had been given an injection (i.p.) of 0.03 mg CdCl2.2.5H2O containing 1.0 microCi of 109 CdCl2. When pure, DEDMS is a waxy solid with a melting point of 61-62 degrees C which is soluble in warm peanut oil. Its LD50 value (i.p.) in mice is approximately 2.6 mmol/kg, a value which allows it to be given at a higher dosage than other known lipid-soluble dithiols. This compound is especially effective in reducing hepatic and whole body levels of cadmium; it is not as effective as 2,3-dimercaptopropanol (BAL) in reducing renal cadmium levels.
Animals↗
Dithiocarbamate treatment of chronic cadmium intoxication in mice.
The dithiocarbamate analogs, N-benzyl-N-dithiocarboxy-D-glucamine (BDCG) and N-cyclohexyl-N-(2-hydroxy-3-sulfonatopropyl)dithiocarbamate (CAPSO-DTC), were evaluated as cadmium (Cd) antagonists in mice which had received repetitive injections of Cd to effect accumulation of substantial levels of metallothionein-bound Cd in kidneys and livers. BDCG was highly effective in lowering whole body Cd stores and renal Cd concentrations. While the percent of renal Cd mobilized decreased with increasing Cd concentrations, the total amount of Cd mobilized increased. CAPSO-DTC was also effective in reducing whole body Cd levels, but appeared to have less affinity for renal Cd than did BDCG. Treatment of Cd-laden mice with BDCG provoked only a modest elevation of serum creatinine levels, suggesting that the complex of Cd with BDCG may be less nephrotoxic than the complex of Cd with EDTA or dimercaprol. The log of the percent reduction of renal Cd by BDCG was found to be a linear function of the pretreatment renal Cd concentration, and reductions of whole body Cd burdens correlated closely with reductions of liver and kidney Cd concentrations. It was suggested that a Cd complexing agent of the dithiocarbamate class may have ultimate application in a provocative methodology to estimate body or organ Cd stores based upon the amount of Cd excreted following a standard dose of the chelator.
Animals↗
The effect of zinc on the dithiocarbamate-induced mobilization of cadmium deposits in mice.
In comparison with similar experiments in which no zinc acetate was used, the addition of small amounts of zinc acetate to sodium N-methyl-N-dithiocarboxyglucamine produces a significant increase in the amount of cadmium mobilized from the liver and kidneys of mice loaded ip with 10 mg CdCl2.2.5H2O/kg 2 wk prior to the initiation of treatment. Neither treatment results in the transport of significant amounts of cadmium to the brain. The injection of zinc acetate alone did not produce this effect. Experiments in which zinc acetate in drinking water was administered to cadmium-loaded animals showed that the liver and kidney cadmium levels were significantly increased, presumably via zinc-mediated processes in which cadmium from other organs was mobilized to the liver and kidneys.
Acetates↗
Dithiocarbamate inhibition of cadmium-induced changes in spermatozoan acetyltransferases.
The administration of sodium N-methyl-N-dithiocarboxy-D-glucamine (NaG) subsequent to the administration of CdCl2.2.5H2O to male rats, inhibits the cadmium-induced decreases in spermatozoan acetyltransferase (AT) levels and provides marked protection against the cadmium-induced morphologic testicular changes in the cauda and corpus and partial protection against the changes in the caput.
Acetyltransferases↗
Amphipathic dithiocarbamates as cadmium antagonists: N-cyclohexyl-N-sulfonatoalkyl derivatives.
Disodium salts of the substituted dithiocarbamates (DTCs) N-cyclohexyl-N-(2-sulfonatoethyl) DTC, N-cyclohexyl-N-(3-sulfonatopropyl) DTC, and N-cyclohexyl-N-(2-hydroxy-3-sulfonatopropyl) DTC were synthesized and assessed as complexing agents for reducing organ concentrations of cadmium (Cd) in mice. At least one week after mice were given 0.03 mg of CdCl2.2.5 H2O containing 1.0 microCi of 109CdCl2 ip they were treated ip with various doses of each DTC. Administration of 4.44 mmoles/kg of each analog q2dx4 produced about a 60% reduction in the whole-body Cd burdens. There was approximately a 50% reduction of renal Cd concentrations and a greater than 90% reduction of hepatic Cd. There was no significant effect on the Cd levels in pancreas, spleen, testes, or brain. Mobilization of organ Cd stores led to excretion of Cd principally in the feces; treatment with 2.22 mmoles/kg of each analog qdx3 promoted a cumulative excretion of 32-40% of the administered metal. Rational design of potential Cd complexing agents is discussed with reference to the relative aqueous and lipid solubilities of the N,N-substituents on DTC congeners.
Animals↗