Myron A. Holscher

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the golden Syrian hamster.

Abstract Lethality, pathology, and various clinical chemical parameters were assessed in the hamster following a single ip or po treatment with 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD). A single dose, 50-day LD 50 of greater than 3000 μg TCDD/kg, ip, was obtained for male and female hamsters while the LD 50 of orally administered TCDD was found to be 1157 μg/kg. Thus, the hamster appears to be the least sensitive mammalian species to the lethal effect of TCDD that has yet been investigated. TCDD treatment generally reduced the rate of body weight gain, with orally treated hamsters exhibiting the greatest reduction in rate. Thymic atrophy was the most consistent pathologic finding in TCDD treated hamsters. No histopathological changes were seen in the liver, spleen, kidneys, adrenals, or heart. Moderate to severe ileitis and peritonitis were found in many of the hamsters which died following oral treatment with TCDD. This lesion usually affects the distal ileum and consists of a marked hyperplasia of the mucosal epithelium with mild to severe hemorrhaging and necrosis. The intestinal lesion probably contributed in part to the greater lethality of TCDD in orally treated hamsters. A significant increase in serum alkaline phosphatase, bilirubin, protein, iron, cholesterol, and a decrease in serum albumin, chloride, urea nitrogen, and triglycerides were found in hamsters following both ip and po treatment with TCDD.

The effect of total parenteral nutrition on the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the rat

Abstract The effects of total parenteral nutrition (TPN) upon the toxicity of 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) in rats has been studied. At doses of 50 or 100 μg/kg, TPN-fed, TCDD-treated rats demonstrated a weight gain similar to that of TPN-fed controls, but died at Days 13–17 following treatment. Gross examination of moribund animals revealed icterus, thymic atrophy, increased adipose tissue depots, and enlarged livers. The liver weights ranged from two to three times those from TPN-fed control animals. Histologically the livers were severely necrotic. Most cells which were not necrotic were markedly swollen and disorganized. Extensive vacuolization of hepatocytes and cystic areas containing cell debris were also prominent features. Whereas glycogen stores were depleted, the total content of water, lipid, protein, RNA, and DNA in the livers was increased. Alterations in cytochrome P -450-associated monooxygenase activities were also observed. Statistically significant increases in serum iron, bilirubin, alkaline phosphatase, serum glutamic-oxaloacetic transaminase and cholesterol were found in the TPN-fed, TCDD-treated animals. Serum protein, glucose, and triglycerides were significantly decreased except in a few severely moribund animals in which hyperglycemia was observed. The results in the TPN-fed, TCDD-treated rats were compared with TCDD-treated rats fed a chow diet ad libitum . At the same dose of TCDD, the liver damage in the TPN-fed, TCDD-treated rats was histologically more severe.

A possible protective role for reduced glutathione in aflatoxin B1 toxicity: Effect of pretreatment of rats with phenobarbital and 3-methylcholanthrene on aflatoxin toxicity

Abstract A possible protective role for reduced glutathione (GSH) in aflatoxin B 1 -induced hepatotoxicity in male rats was investigated. A 200-mg/kg dose of cysteine (a glutathione precursor) given prior to the administration of aflatoxin B 1 , reduced the hepatic necrosis and partially reversed the decrease in the activity of the hepatic drug metabolizing enzyme system seen on administration of the same dose of aflatoxin B 1 alone. On the other hand, prior administration of diethyl maleate, a compound which depletes liver GSH, enhanced the aflatoxin-induced hepatotoxicity. In contrast to untreated rats, pretreatment with phenobarbital appeared to block the liver necrosis and the decrease in mixed function oxidase activity seen on administration of aflatoxin B 1 . On the other hand, pretreatment of the rats with 3-methylcholanthrene did not protect against the hepatic damage or the decrease in the activity of benzphetamine N -demethylase seen on administration of aflatoxin B 1 .

Toxicity of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin in larval and adult forms ofRana catesbeiana

SummaryVarying doses of TCDD ranging from 25 to 1000 μg/kg were administered to the larval and adult forms of the American bullfrog,Rana catesbeiana. Doses of TCDD as high as 1 mg/kg failed to have any significant effect upon survival or completion of metamorphosis in tadpole and doses of up to 500 μg/kg had no effect on survival of adult frogs. Histopathological examination of various tissues from the metamorphosed tadpoles and adult frogs failed to show any abnormalities.

L-methionine antagonism of cis-platinum nephrotoxicity.

L-Methionine administered simultaneously with cis-platinum (CDDP) iv results in a significant reduction of the nephrotoxicity normally associated with CDDP without any apparent effect on the antineoplastic activity for rats bearing the Walker 256 carcinosarcoma. CDDP given with L-methionine at a 1:20 mole ratio can be administered to rats at doses up to 35 mg/kg iv with the survival of all treated animals (3/3) and up to 56 mg/kg iv (bolus injection) with the survival of 3/6 animals, while CDDP administered alone at these levels is lethal. A reduced level of protection against the nephrotoxicity was also achieved at lower mole ratios of L-methionine to CDDP. Renal function was monitored using BUN and serum creatinine levels, and gastrointestinal toxicity by weight changes during the course of the experiments. A histopathological examination of the kidneys was also performed to evaluate the protection provided by L-methionine. Under the conditions used, the reaction between L-methionine and CDDP does not appear to proceed so rapidly as to interfere with the antitumor activity of the CDDP. The examination of structural analogs as agents for the control of CDDP-induced nephrotoxicity revealed that the C-S-C-group is the essential group for the protective action in these structures. Although L-methionine can provide renal protection in rats given high doses of CDDP, it does not prevent the accumulation of platinum in the kidney.

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on mammalian cells in tissue cultures

Abstract The effects of 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD), a toxic byproduct of the production of the herbicide, 2,4,5-trichlorophenoxyacetic acid, upon growth has been studied with in vitro cultures of the following mammalian cell types: HeLa; Balb-3T3; SV101, virus (SV40)-transformed 3T3 mouse fibroblasts; human foreskin fibroblasts, and human lymphocytes. In all cases TCDD added in a final theoretical concentration of 10 −6 m to the culture medium prior to the addition of cells resulted in no significant inhibition of growth measured after a period of 4 days. Electron microscopic examination of the TCDD-treated cells did not reveal any changes in morphology as compared to untreated cells. Incubation of human fibroblasts and SV101 cells with 14 C-labeled TCDD showed that incorporation of the TCDD into the cells did occur.

Control of the Nephrotoxicity of Cisplatin by Clinically Used Sulfur-Containing Compounds

Several clinically used sulfur-containing compounds were examined as potential antagonists for the nephrotoxicity of cis-platin in Sprague-Dawley rats. The compounds studied were biotin, captopril, cefoxitin, cephalexin, the sodium salt of penicillin G, sulfathiazole, and thiamine hydrochloride. Biotin, captopril, cephalexin, and sulfathiazole were found to have a significant effect in reducing the nephrotoxicity of cisplatin when administered simultaneously with cisplatin via an intravenous route in the rat. Biotin was the most effective in providing renal protection and sulfathiazole the least effective, based upon BUN, serum creatinine values, and weight changes, though all four of these compounds provided a considerable measure of protection against the typical cisplatin-induced nephrotoxicity. The effect of the simultaneous administration of cisplatin with biotin, cephalexin, and sulfathiazole was examined on the antitumor activity of cisplatin toward the L1210 murine leukemia in the DBA/2 mouse and the Walker 256 carcinosarcoma in the rat. With the L1210 murine leukemia no loss of antitumor activity was found for any of the compounds. With the Walker 256 carcinosarcoma some loss of antitumor activity was found with biotin. Both biotin and sulfathiazole are shown to be promising candidates for use in the suppression of the adverse effects of cisplatin, and other sulfur-containing compounds currently in clinical use may have equivalent or superior properties in this respect.

The relative nephrotoxicity of cisplatin,cis-[Pt(NH3)2(guanosine)2]2+, and the hydrolysis product of cisplatin in the rat

SummaryAn examination of the comparative nephrotoxicity in the tat of cisplatin, its hydrolysis product (mostlycis-[Pt(NH3)2Cl(H2O)]+ under the conditions applied), andcis-[Pt(NH3)2(guanosine)2]2+ revealed that these compounds differed significantly in the extent of renal damage they produced following their i.v. injection in Sprague-Dawley rats. The hydrolysis product was found to be the most toxic of the three complexes studied and produced nephrotoxicity at doses lower than those at which cisplatin was nephrotoxic. Under the conditions used, the i.v. administration ofcis-[Pt(NH3)2(guanosine)2]2+ resulted in no observable signs of nephrotoxicity at levels at which an equimolar dose of cisplatin produces clear evidence of renal function impairment and morphological alterations. The nephrotoxicity of these complexes appears to be generally related to the ease with which they undergo nucleophilic substitution reactions. The lack of substantial nephrotoxicity found forcis-[Pt(NH3)2(guanosine)2]2+ suggests that the products resulting from the action of the DNA repair processes on platinated DNA do not contribute significantly to the nephrotoxicity of cisplatin. Renal platinum levels found following the administration of these compounds correlated with the degree of nephrotoxicity produced by each compound, but no general correlation of nephrotoxicity and renal platinum levels was found. The nephrotoxicity ofcis-[Pt(NH3)2Cl(H2O)]2+ on a molar basis was estimated to be approximately 3 times as great as that of cisplatin itself.

Relative effectiveness of some compounds for the control of cisplatin-induced nephrotoxicity

Several procedures which have been reported as effective for the control of cisplatin induced nephrotoxicity were compared in the Sprague-Dawley rat using the same dose of cisplatin. The treatments examined were based on the use of sodium thiosulfate, sodium diethyldithiocarbamate (DDTC), glutathione (GSH), sodium N-methyl-D-glucamine dithiocarbamate (NaG) and S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). The differences in the effectiveness of the procedures were assessed using BUN and serum creatinine values, histopathological examination, body weight changes, and renal platinum levels as indices. The effect of such treatments on the antineoplastic activity of cisplatin were examined with both the Walker 256 carcinosarcoma in the rat and the L1210 murine leukemia in mice. Under the conditions used, GSH was found to be more effective than the other nucleophiles in protecting against the nephrotoxicity of cisplatin while providing the least amount of interference with the antitumor activity as measured against the Walker 256 carcinosarcoma and the L1210 murine leukemia. Simultaneous i.v. administration of cisplatin and any of the sulfur-containing nucleophiles leads to a significant protection against the nephrotoxicity but reduced the anti-neoplastic activity of cisplatin when measured against the Walker 256 carcinosarcoma.

Effect of monoisoamyl meso‐2,3‐dimercaptosuccinate on the pathology of acute cadmium intoxication

The ability of monoisoamyl meso-2,3-dimercaptosuccinate (Mi-ADMS) to offset the characteristic organ pathology of intraperitoneally administered cadmium chloride (CdCl2) and that of the cadmium-cysteine complex has been examined in male Wistar rats. The tissues examined for damage were the testes, kidney, liver, pancreas, and bone marrow. At a high dose of CdCl2 (0.03 mmol/kg, ip) testicular damage was completely prevented by Mi-ADMS (0.50 mmol/kg, ip) given immediately. A decrease in the protective ability of the antagonist was observed following delayed administration of Mi-ADMS given at 1, 2, 4, and 24 h post CdCl2. At a lower dose of CdCl2 (0.006 mmol/kg, ip), Mi-ADMS furnished essentially full protection from testicular damage when given (0.50 mmol/kg, sc) at 0 and 1 h after CdCl2. The administration of cadmium-cysteine complex (0.01 mmol/kg, ip) induced notable renal tubular damage, which was antagonized by the administration of Mi-ADMS (0.50 mmol/kg, ip) as late as 4 h after the complex. At a 24-h delay, extensive tubular necrosis was found on sacrifice after 4 d. The administration of cadmium-cysteine complex ip reduced, but did not eliminate, the characteristic damage of the seminiferous tubules found for cadmium alone. There is a progressive reduction of testicular weight as the interval between cadmium and antagonist administration increases. The average kidney weights of the animals given CdCl2-cysteine complex were increased in comparison to normal controls. The antagonistic effects of Mi-ADMS treatment on cadmium intoxication in the kidneys and the testes of rats is very similar to that found for effective dithiocarbamate antagonists. In order to obtain complete protection of the testes from the deteterious effects of cadmium, such antagonists must be administered no later than about 1 h after the cadmium.