Neurotoxic effects of the anti-varicella zoster virus agent 2′-valeryl-6-methoxypurine arabinoside in monkeys and rats dosed orally for 90 days

The 2′-valerate ester of 6-methoxypurine arabinoside (170U88), a nucleoside analog with anti-varicella zoster virus (VZV) activity, was given to monkeys and rats. In subchronic preclinical toxicity studies, dosing was by gavage to monkeys (distilled water vehicle) and rats (0.5% methylcellulose vehicle) for 90 days. Groups of 5 male and 5 female monkeys (Macaca fascicularis) were given 170U88 at 0, 25, 50, or 100 mg/kg/day. The daily dose was given in two equal portions with 6 hr between doses. Monkeys in the high-dose group lost weight. Food consumption was decreased for mid- and high-dose monkeys and for low-dose female monkeys. Slightly decreased values for erythrocyte and leukocyte counts at the mid- and high dose were fully reversed during an 8-week recovery period. Two high-dose male monkeys and a middose female monkey developed signs of central nervous system toxicity and were necropsied before dosing was complete. These signs were first observed in the fifth week of dosing and included body tremors, incoordination, reduced activity, sleepiness, stupor, and lack of eye tracking. Axonal lesions were observed in histologic sections of sciatic nerve in monkeys at all dose levels. Neither the signs of central nervous system toxicity nor the axonal lesions reversed during the 8-week recovery period. Groups of 14 male and 14 female CD rats (Sprague-Dawley derived) were given single daily doses of 170U88 at 0, 150, 300, or 600 mg/kg. Body weights were decreased at all dose levels and food consumption was decreased for mid- and high-dose rats. Small increases in values for erythrocyte count, hemoglobin, and packed cell volume and small decreases in values for glucose, serum protein, and serum albumin were limited to high-dose rats and reversed during a 4-week recovery period. High-dose rats also had reversible liver lesions consisting of necrosis of individual hepatocytes, megalocytosis, occasional mitotic figures, and biliary stasis. Clinical and morphologic indications of central nervous system toxicity in the rats consisted of altered exploratory behavior at the high dose and groups of small vacuoles in cerebellar white matter at all dose levels. Cerebellar vacuolation was observed in rats examined at the end of the exposure period and also in rats examined after the 4-week postdose recovery period. Signs interpreted as peripheral nervous system toxicity were limited to rats in the high-dose group and consisted of hindquarter weakness, slow righting and placing reflexes, and ataxia. Again, these findings did not reverse during the recovery period. Thus, signs of both central and peripheral nervous system toxicity were observed in both monkeys and rats. These neurotoxic effects resulted in the decision to stop further development of 170U88.     

A 26-week inhalation toxicity study with formaldehyde in the monkey,rat, and hamster

This inhalation study involved simultaneous exposure of five groups of 6 male Cynomolgus monkeys, 20 male and 20 female Fischer 344 rats, and 10 male and 10 female Syrian golden hamsters for 22 hr per day, 7 days per week for 26 weeks to formaldehyde gas. The cumulative mean exposure concentrations were 0, 0, 0.19, 0.98, and 2.95 ppm for the two control groups, low-, mid-, and high-level exposure groups, respectively. There was no treatment-related mortality during the study. In monkeys, the most significant findings were hoarseness and congestion and squamous cell metaplasia in the nasal turbinates of the 2.95-ppm exposure group. There were no signs of toxicity in the lower-level exposure groups. In the rat, the only observations of possible responses to exposure were found in the 2.95-ppm exposure group. These findings consisted of squamous metaplasia in the nasal turbinates, decreased body weights starting during the second week of the study, and decreased liver weights. In contrast to monkeys and rats, hamsters did not show any significant responses to exposure even at 2.95 ppm. It was concluded that nearly continuous exposure of monkeys and rats for six months at a level of 2.95 ppm of formaldehyde clearly elicited an effect while exposures below this level did not appear to demonstrate an effect. It further appeared that the monkey and rat were more sensitive to formaldehyde exposure than the hamster.     

Toxicological evaluation of substituted dicyclopentadienyliron (ferrocene) compounds

The acute toxicity of 3 substituted ferrocenes: acetylferrocene, ethylferrocene, and 2,2-bis(ethylferrocenyl)propane (Catocene) were studied in rats, rabbits and monkeys. Acetylferrocene was found to be the most toxic. The oral lethal dose was less than 5 mg/kg for female rats, between 5 and 50 mg/kg for male rats, and between 10 and 100 mg/kg for monkeys. The toxicity of acetylferrocene appeared to be delayed, with most mortality occurring on the third day after dosing. Acetylferrocene was also highly toxic by skin or eye exposure. Gross pathological examination revealed signs of pneumonopathy in both the rats and monkeys. The mechanism by which monkeys are less susceptible than rats to the toxicity of acetylferrocene is not clear.     

Chronic toxicity/carcinogenicity studies of gentian violet in Fischer 344 rats: two-generation exposure

A chronic feeding study was carried out in the F1a generation of dosed Fischer 344 rats of both sexes with gentian violet (GV). The test substance was administered in the diet to 570 male and 570 female rats at dose levels of 0 (control), 100, 300 and 600 ppm for 24 months. Rats were killed and necropsied after 12, 18 and 24 months of continuous dosing. Measurements of body weights, food consumption (and dose rate) and mortality and the results of histopathological examination were analysed statistically. Male and female rats fed 600 ppm GV for 24 months showed a decrease in body weights. Average food consumption based on g food/kg average body weight was essentially equal in all groups. Mortality at the end of the study (24 months) was approximately 33% in the controls for both males and females and approximately 66% in females of the high-dose group and 48 and 39% in males of the mid- and high-dose groups, respectively. All dose-related neoplastic pathology was noted at the final necropsy. Following 24 months of dosing, there was a significant difference from the controls in the incidence of follicular cell adenocarcinoma of the thyroid gland for both males (600 ppm GV) and females (300 and 600 ppm GV). Although the incidences were very low, statistical analysis showed a significant difference from the controls for hepatocellular adenomas in the mid-dose group of the females and the mid- and high-dose groups of the males. A dose-time-related incidence of mononuclear cell leukaemia was also noted in the females. There was high background incidence of the leukaemia. Several non-neoplastic dose-related lesions were observed in both males and females, principally in the 18- and 24-month necropsies. Almost all of these lesions were focal changes in the liver, many of which were probably related to the mononuclear cell leukaemia.     

Biosynthetic human growth hormone: subchronic toxicity studies in rats and monkeys

Biosynthetic human growth hormone was injected subcutaneously in rats for 90 days and in cynomolgus monkeys for 30 days. The daily doses were 0.5, 3.3 and 25 IU kg-1 (rats) and 0.3 and 15 IU kg-1 (monkeys). The growth hormone was tolerated well in both rats and monkeys. No drug related deaths occurred and all animals appeared to be normal and also behaved normally throughout the dosing period. Increased body weight gain, increased food utilisation and increased organ weights were seen in the rats in the high and intermediate dose groups. The higher doses of human growth hormone (3.3 and 25 IU kg-1) caused a glandular hyperplasia of the mammary gland in male and female rats with evidence of secretory activity. In the female monkeys secretory activity was seen without any sign of mammary gland hyperplasia. Mucification of the vaginal epithelium and stress induced prostatitis was observed in the rats. Additional treatment related changes in the rats were an increased haematopoietic activity in the spleen and an increase in the amounts of calcium and phosphate excreted in urine. An increase in fasting plasma glucose levels was seen in the male monkeys on the high dose level. The changes observed during the treatment periods presumably represent exaggerated pharmacological effects of the growth hormone.     

Chronic Nephropathy and Renal Carcinogenicity of o-Benzyl-p-chlorophenol in F344/N Rats and B6C3F1 Mice

o-Benzyl-p-chlorophenol, an aryl halide biocide, was evaluatedin male and female F344/N rats and B6C3F₁ mice in a series ofsubchronic and 2-year toxicity and carcinogenicity studies.Kidney was the primary target of toxicity in the 13-week gavagestudies in rats and mice, with increased nephropathy noted aslow as 240 mg/kg in male rats. Considering the nephropathy tobe dose-limiting, the chronic (2-year) study was conducted atlower doses (male rats: 30, 60, or 120 mg/kg; female rats: 60,120, or 240 mg/kg; male and female mice: 120, 240, or 480 mg/kg;in corn oil; n=50/group). Survival and body weights of dosedrats were similar to controls in the 2-year study. Survivalof high-dose male and female mice, and body weights of all dosedmale and mid- and high-dose female mice, were lower than controls.The incidence and severity of nephropathy increased with doseand length of treatment in both rats and mice. There was anincreased incidence of renal tubule adenomas or carcinomas inboth the mid- and high-dose male mice. Despite similar evidenceof nephropathy, however, there were no increased incidencesof neoplasms in female mice or in male or female rats. Thisstudy suggests therefore that while nephrotoxicity may havebeen a necessary component, factors other than the marked nephrotoxicityof o-benzyl-p-chloro-phenol were critical to the developmentof renal carcinogenesis induced in only male mice.     

Dermal toxicity and carcinogenicity of 4-vinyl-1-cyclohexene diepoxide in Fischer rats and B6C3F1 mice

4-Vinyl-1-cyclohexene diepoxide (VCHD) is used as a chemical intermediate and as a reactive diluent for diepoxides and epoxy resins. Studies were conducted by administering VCHD in acetone by dermal application, 5 days per week for 105 weeks, to groups of 60 rats of each sex at 0, 15, or 30 mg/animal. Groups of 60 mice of each sex were administered 0, 2.5, 5, or 10 mg/animal on the same schedule for up to 103 weeks. Ten animals from each group were humanely killed, necropsied, and examined histopathologically during Month 15. At the 15-month evaluation, 2 of 10 male rats that received 30 mg had a squamous cell carcinoma of the skin at or adjacent to the site of application. Squamous cell papillomas and carcinomas were seen in all mice that received 5 or 10 mg. Two of nine female mice given 10 mg had granulosa cell tumors of the ovary, and one of nine female mice given 10 mg had an ovarian papillary cystadenoma. In the 2-year studies, body weight and survival were lower in high-dose rats and mid- and high-dose mice than in vehicle controls. All high-dose male mice died by Week 83; remaining high-dose female mice were killed during Week 84 for humane reasons. Squamous cell papillomas of the skin in dermally exposed male rats and squamous cell carcinomas and basal cell adenomas or carcinomas of the skin in exposed male and female rats were increased. The incidence of squamous cell carcinomas of the skin was increased in male and female mice at all dose levels. Mid- and high-dose female mice had an increased incidence of benign or malignant granulosa cell tumors and of benign mixed tumors of the ovary.     

Toxicological properties of closantel

The acute, subacute and chronic toxicity studies in laboratory animals showed that closantel is a well tolerated substance. At multiples of the clinical dose, overdosing might result in central nervous system effects and death. Repeated oral dosing was without effects up to 40 mg/kg in rats and dogs except for focal swelling of the epididymis in male rats at 40 mg/kg due to formation of spermatic granulomas. In sheep repeated dosing at 10 and 40 mg/kg orally and at 5 and 20 mg/kg intramuscularly every four weeks during 40 weeks demonstrated an acceptable safety margin in this target species. Reproduction studies including a three-generation study in rats showed that fertility was not affected except slightly in male rats at 40 mg/kg whereas an embryotoxic or teratogenic potential in rats and rabbits was absent. Peri- and postnatal parameters in rats were not affected. In target animals, reproduction was extensively studied in bulls, rams and ewes showing no risk of closantel for reproduction parameters. A mutagenic potential was found to be absent in a Salmonella Ames test, a sex-linked recessive lethal test in Drosophila melanogaster and a dominant lethal test in male and female mice. In 400 mice and 400 rats closantel was shown not to be carcinogenic. Tolerance studies in sheep and cattle demonstrated that oral and parenteral clinical doses were very well tolerated and devoid of serious side-effects.     

Safety evaluation of ABELCET, an amphotericin B lipid complex (ABLC): toxicity studies in rats

ABELCET (ABLC) is a widely used amphotericin B lipid complex formulation that is approved for use in the treatment of invasive fungal infections in patients who are refractory or intolerant of conventional amphotericin B (AmB). The safety profile of ABLC has been characterized in two acute and two repeat-dose toxicity studies in rats. The acute toxicity studies indicated that single intravenous doses of ABLC are at least 20 times less toxic than conventional amphotericin B doses without the lipid formulation, Fungizone. Intravenous doses of 0, 1, 3, or 10 mg/kg/day to groups of rats (10 to 15 rats/sex/group) for 31 days elicited no mortality or overt clinical signs of toxicity, whereas alternate intravenous/intraperitoneal doses (three each per week) for 6 months, produced one death in the control group, one in the intermediate-dose group, and two in the high-dose group. Clinical signs (predominantly piloerection and hunched posture at 10 mg/kg/day) were attributed to granulomatous inflammatory lesions in the abdominal wall, mesentery, and omentum, which were produced by the intraperitoneal injections of ABLC. Feed consumption and body weight gains decreased in high-dose male rats in the one-month study and were significantly lower in male rats at 3 and 10 mg/kg/day in the 6-month study. In contrast, water consumption increased in male and female rats in both studies. Trends of minimal to moderate, dose-related increases in relative kidney, liver and spleen weights, and histological evidence of hypertrophy and hyperplasia of reticuloendothelial cells in the liver and spleen and mild, dose-related impairment of renal function occurred in both the 1- and 6-month studies. Examination of high-dose rats following a recovery period of 28 days after completion of 31 days of dosing suggested that treatment-related changes were reversible. The observed changes for ABLC are similar to those for other amphotericin B lipid formulations, such as AmBisome (LAmB), except for the hepatoxicity, which was observed for LAmB, but not for ABLC.     

Reproductive toxicity of dimethyl methyl phosphonate (DMMP) in the male Fischer 344 rat

Dimethyl methyl phosphonate (DMMP) has been considered for use by the U.S. Armed Forces as a nerve gas simulant in a variety of experimental situations to simulate the physical properties of nerve gases, but not the neurotoxic properties. Dimethyl methyl phosphonate is also used as a flame retardant for urethane foams and polyester resins. This study was conducted to determine the reproductive toxicity of DMMP after subchronic dosing. DMMP was administered to male Fischer 344 rats by gavage 5 days/week for 90 days at dosages of 0, 250, 500, 1000, and 2000 mg/kg, and all animals survived this dosing schedule. At Day 84, the rats were mated to untreated female Fischer 344 rats. There was a dose-related decrease in sperm count, sperm motility, and the male fertility index. The male fertility index was 70, 75, 60, 40, and 0% in the 0, 250, 500, 1000, and 2000 mg/kg dose groups. DMMP acted as a dominant lethal mutagen as demonstrated by an increase in the number of resorptions with increasing doses of the drug. The percentage of resorptions in the control group was 6.1% and increased to 14.9, 37.8, and 79.1% in the 250, 500, and 1000 mg/kg groups, respectively. The testes of the male rats were examined histologically to determine the relationship between reproductive function and pathologic abnormalities. DMMP altered reproductive function at all dose levels, while histologic abnormalities of the testis were seen only in the high-dose group. Changes in the testes of the high-dose animals were characterized by lack of spermatogenesis or by degeneration, vacuolization, and necrosis of cells in the spermatogenic tubules. Histopathologic abnormalities of the kidney were seen in some animals from each of the dosed groups and microscopic changes of the prostate were seen in some of the high-dose animals.     

Toxicity of the mycotoxin, cyclopiazonic acid, to Sprague-Dawley rats

Groups of male Sprague-Dawley rats received po doses of cyclopiazonic acid (CPA) on four consecutive days at 0.0, 0.2, 2.0, 4.0, or 8.0 mg kg-1 days-1. Clinical signs of toxicity were observed only in the two highest dose groups. Rats in the highest dose group exhibited abnormal behavior, diarrhea, and other signs of toxicity after several days of dosing, and most were moribund before the last scheduled dose was administered. Liver and spleen were more severely affected than other organs in the two highest dose groups. Livers contained diffuse pycnotic nuclei and, in some high-dose rats, focal areas of coagulative necrosis. In the high-dose group aspartate and alanine aminotransferase activities were elevated, cytochrome P-450 concentration was decreased, and glutathione S-transferase activity was unchanged. Spleens were hemorrhagic and white pulp contained necrotic lymphocytes. White cell counts were decreased in a dose-related manner in the two highest dose groups. The gastrointestinal tract of high-dose rats contained pycnotic nuclei, and sites of necrosis were observed in stomach, but these lesions were limited to several animals, and were generally mild. Pathologic changes in conjunction with decreased feed and water intake probably contributed to the general deterioration of high-dose rats that resulted in death.     

重组人白细胞介素-12对食蟹猴的反复给药毒性研究

目的:观察重组人白细胞介素-12(rhIL-12)对食蟹猴的长期毒性。方法:食蟹猴皮下注射给予rhIL-12,剂量分别为0.5,5和40μg·kg-1,每周3次,共13周。检测指标包括临床症状、血液学、血生化、免疫、血清抗体和组织病理学检查。结果:rhIL-12给药后导致动物出现腹泻、面部及眼睑部肿胀、腹股沟淋巴结肿大、溃疡、及注射局部红斑和硬结等临床症状,并出现贫血和白细胞分类异常,血液生化指标出现肝脏转氨酶升高,免疫学指标出现外周血总T淋巴细胞比例增加,CD4细胞百分率下降,CD8细胞百分率增加。第7次给药后,给药组动物产生了rhIL-12抗体。结论:食蟹猴皮下注射给予rhIL-12,毒性靶器官和组织为血液系统、肝脏、心脏、肾脏和淋巴结等免疫调节系统,其安全剂量为0.5μg·kg-1。     

Somatosensory thresholds in monkeys exposed to acrylamide

Six monkeys were trained to report detection of a vibratory or electrical stimulus applied to the fingertip. The vibratory stimuli were presented at two frequencies (40 and 150 Hz). Thresholds were determined with a tracking procedure before, during, and after dosing. Each monkey served as its own control. Four monkeys were dosed orally with 10 mg/kg of acrylamide 5 days a week until the appearance of toxic signs. The total administered dose varied between 320 and 450 mg/kg. The other two monkeys served as time-matched controls. All the monkeys were observed 5 days a week. They were also weighed and presented with a visuomotor task (pickup test) twice a week. Weight loss usually preceded the onset of gross behavioral disturbances, such as loss of balance, tremor, or decreased activity. Impaired coordination, as revealed with the pickup test, paralleled weight loss. Electrical sensitivity was not affected. Vibration sensitivity, however, fell during dosing and remained impaired for several months after dosing ceased, outlasting all the other effects. Recovery of the other indices occurred relatively soon after dosing ended. These data indicate that vibration sensitivity testing can trace the time course of intoxication and recovery in toxic peripheral neuropathies. Furthermore, the differential results obtained with vibratory and electrical stimulation are consonant with a primary effect on end-organ receptors.     

Investigations of the Carcinogenicity of the LH-RH Analog Buserelin (HOE 766) in Rats Using the Subcutaneous Route of Administration

A carcinogenicity study with the LH-RH analog buserelin (HOE766) was conducted in male and female Wistar rats. The compoundwas administered subcutaneously daily for a period of 24 monthsto groups of 50 male and 50 female animals in doses of 0.0002,0.0006, or 0.0018 mg/kg body wt, followed by a 6-month recoveryperiod without any treatment. Male and female rats (100 each)received physiological saline and served as controls. The bodyweight development of all male rats was regular, but in femalesat all three dose levels significantly increased body weightgain in comparison to the control animals occurred. Food consumptionwas not affected in any group. No treatment-related changesin clinical signs and hematological parameters were noted. Thechronic administration of HOE 766 did not influence the survivalof the male rats while in females it was dose-dependently increased.Endocrinological examinations revealed decreased serum testosteronelevels in males and reduced serum progesterone levels in femalesduring the treatment period; the changes reverted to normalduring the recovery period. Reduced weights of the testes anduteri as well as increased weights of the pituitaries and ovariesin females are compound-related. Histological examination ofthe ani mals which died intercurrently or were killed in extremisor at the end of the recovery period revealed irreversible andpartly dose-dependent changes in testes and uterus, due to thepharmacodynamic properties of HOE 766, but gave no indicationof any carcinogenic effect of the compound.     

Safety evaluation of an enzymatically-synthesized glycogen (ESG)

An enzymatically-synthesized glycogen (ESG), intended for use as a food ingredient, was investigated for potential toxicity. ESG is synthesized in vitro from short-chain amylose by the co-operative action of branching enzyme and amylomaltase. In an acute toxicity study, oral administration of ESG to Sprague–Dawley rats at a dose of 2000 mg/kg body weight did not result in any signs of toxicity. ESG did not exhibit mutagenic activity in an in vitro bacterial reverse mutation assay. In a subchronic toxicity study, increased cecal weights noted in the mid- (10%) and high-dose (30%) animals are common findings in rodents fed excess amounts of carbohydrates that increase osmotic value of the cecal contents, and thus were considered a physiological rather than toxicological response. The hematological and histopathological effects observed in the high-dose groups were of no toxicological concern as they were secondary to the physiological responses resulting from the high carbohydrate levels in the test diets. The no-observed-adverse-effect level for ESG in rats was therefore established to be 30% in the diet (equivalent to approximately 18 and 21 g/kg body weight/day for male and female rats, respectively). These results support the safety of ESG as a food ingredient for human consumption.     

A 13-week vapor inhalation study of 3,3-dimethyl-2-butanol in Sprague-Dawley rats

Four groups of male and female Sprague-Dawley rats were exposed for 13 weeks to 3,3-dimethyl-2-butanol (PA) at concentrations of 0.00, 0.20, 1.00 or 5.00 mg/l (1 mg/l = 240 ppm). Exposures were for 6 hr per day, 5 days per week with sacrifices at 7 and 13 weeks of exposure, and at 4 weeks after exposure. The test animals were evaluated for abnormalities in physiology, behaviour, clinical laboratory parameters, and gross and microscopic morphology. No abnormalities were detected in electrocardiograms, respiratory indices, spontaneous activity, passive avoidance activity and open-field behaviour. Clinical signs related to PA exposure included alopecia, ataxia and lacrimation. There were no biologically significant between-group differences in body-weights during the study. The clinical laboratory data demonstrated a 30% increase in serum cholesterol and bilirubin at 7 weeks in high-dose males and an increase in urea nitrogen in intermediate and high-dose males at 13 weeks. There were no abnormalities in hematologic or coagulation parameters. At necropsy there were no significant gross abnormalities; however, examination of organ weights revealed enlarged kidneys in high-dose male rats at 13 weeks, enlarged ovaries in high-dose female rats at 13 weeks, and microscopic study of tissue sections revealed minimal to mild renal tubular injury in high and possibly intermediate dose males at several sacrifices. These findings suggest that the primary target organ of PA, when given by inhalation, is the kidney in male rats and possibly the ovary in female rats. The renal changes in the high-dose males were not fully reversible during the recovery period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Subchronic peroral toxicity of triethylene glycol in the Fischer 344 rat

Ethylene and diethylene glycols produce systemic toxicity, including nephrotoxicity, by acute and repeated po dosing. To determine the potential for triethylene glycol (TEG; CAS Number 112-27-61) to produce nephrotoxicity, or other organ/tissue injury, a subchronic (90-d) study was conducted by continuous inclusion of TEG in the diet of Fischer 344 rats. This was preceded by a probe 14-d study. For both studies the dietary concentrations were 0 ppm (control), 10,000, 20,000 or 50,000 ppm TEG, resulting in daily TEG consumptions in the 14-d study of 1132, 2311 or 5916 mg/kg with males, and 1177, 2411 or 6209 mg/kg with females. The corresponding values for the 90-d study were 748, 1522 or 3849 mg/kg (males), and 848, 1699 or 4360 mg/kg (females). In the 14-d study there were no mortalities or clinical signs, and no effects on body weight, hematology, serum chemistry, organ weights, and gross or microscopic pathology. Food consumption was increased at the high dosage. Urinalysis showed increased urine volume and decreased pH with high dose males and females, and increased volume with mid-dose males. In the subchronic study there was neither mortality nor signs of toxicity, and no dosage-related effects with serum chemistry, gross and microscopic pathology. Body weights were reduced during the dosing period with both males and females of the high dosage. Body weight gains were reduced at all dosages with males and females. No hematological effects were seen with females, but males of the mid- and high-dosage groups had slightly reduced erythrocyte count and hematocrit, and high-dose males had decreased hemoglobin concentration with increased mean corpuscular volume. These were considered to reflect a mild hemodilution related to the absorption of large TEG doses. Urinalysis showed dosage-related decreased pH, and increased urine volume mainly at the high dose. These were probably related to the renal excretion of absorbed TEG and/or metabolites. Kidney weight was increased for high-dose females, and increased relative (to body) weight of kidneys for males and females from the mid- and high-dose groups were observed, probably related to the renal excretion of the absorbed TEG and/or its metabolites. These findings indicate that the subchronic continuous po dosing of TEG to rats does not result in local or systemic specific organ or tissue toxicity. These findings contrast with the known repeated po toxicity, notably nephrotoxicity, produced by ethylene and diethylene glycols. Thus, TEG has significantly lesser potential for systemic toxicity by the po route than its lower molecular weight homologues.     

人脐带间质干细胞对大鼠的免疫毒性研究

目的:研究人脐带间质干细胞(UCMSC)对Wistar大鼠的免疫毒性作用。方法:SPF级Wistar大鼠112只分为4组:溶媒组(给予溶媒5 ml/kg)、低剂量组(给予人UCMSC 1×107个/kg)、高剂量组(给予人UCMSC 5×107个/kg)和对照组(给予大鼠UCMSC 1×107个/kg)。每组28只大鼠,雌雄各14只。大鼠尾静脉注射给药,2周1次,共注射4次。给UCMSC后每周进行受体鼠临床移植物抗宿主病(GVHD)评分,末次注射UCMSC后1、13周检测血IgG、IgM含量,CD3+、CD4+、CD8+T细胞数量,并对大鼠淋巴结、胸腺、脾脏进行脏器系数计算和组织病理学检查。结果:给予UCMSC后,各组大鼠的GVHD评分值均为0。末次给予UCMSC后1周,低、高剂量组雌性大鼠IgG[(0.65±0.12)、(0.63±0.14)g/L]和IgM含量[(0.06±0.01)、(0.06±0.01)g/L]明显高于溶媒组雄性大鼠[(0.41±0.17)g/L、(0.04±0.01)g/L,P<0.01或P<0.05];高剂量组雄性大鼠IgM含量[(0.05±0.01)g/L]明显高于溶媒组雄性大鼠[(0.03±0.01)g/L,P<0.01];对照组雌性、雄性大鼠IgM[(0.06±0.02)、(0.05±0.02)g/L]也明显高于溶媒组(P<0.01或P<0.05)。末次给予UCMSC后13周,各剂量组雌、雄性大鼠IgG、IgM与溶媒组相比差异均无统计学意义(均P>0.05)。末次给予UCMSC后1周,低、高剂量组雌性大鼠的脾脏系数[分别为(0.274±0.016)%、(0.294±0.019)%]明显高于溶媒组[(0.232±0.012)%,P<0.01];高剂量组雄性大鼠的脾脏系数[(0.242±0.027)%]明显高于溶媒组[(0.202±0.012)%,P<0.01];对照组雌、雄性大鼠脾脏系数[分别为(0.261±0.019)%、(0.236±0.014)%]也明显高于溶媒组(P<0.05或P<0.01)。末次给予UCMSC后13周各组大鼠的脾脏和胸腺系数差异均无统计学意义(均P>0.05)。各组大鼠CD3+、CD4+、CD8+T细胞百分比及CD4+/CD8+比值均在正常范围内。各组大鼠胸腺、脾脏和肠系膜淋巴结组织病理学检查均未见明显异常。结论:人脐带间质干细胞可引起正常Wistar大鼠免疫球蛋白含量和脾脏系数的升高,该作用具有一过性和可逆性。     

Sex-related difference in hepatic glutathione conjugation of hexachlorobenzene in the rat.

Hexachlorobenzene (HCB) induces hepatic porphyria and liver cancer in female rats, whereas toxicity is minimal in male rats. HCB is biotransformed to sulfur-containing metabolites originating from conjugation to glutathione (GSH). This study aimed to assess differences in GSH conjugation of HCB between male and female rats. Sprague-Dawley rats of both sexes were given (po, 10 ml/kg in corn oil) five consecutive doses of 100 mg/kg HCB [2 bid (7:30, 15:30) + 1 sid (7:30)]. This cumulative dose produced porphyria in female but not male rats after a delay period of 6 weeks. Animals were killed 0, 6, 12, 18, or 24 hr after the last dose. Hepatic GSH level showed a diurnal cycle in rats of both sexes, but it was more pronounced in males; the minimum level was observed at 12 hr after dosing. The GSH level in HCB-treated male rats was significantly lower than control at 6, 18, and 24 hr, whereas no significant differences were observed for HCB-treated female rats. Biliary excretion of pentachlorothiophenol, a metabolite originating from GSH conjugation of HCB, was higher in male than female rats. Liver cytosolic GSH transferase activity toward 3,4-dichloronitrobenzene was significantly higher than control level in male but not female rats given HCB. GSH transferase activity toward 1,2-epoxy-3-(p-nitrophenoxy)propane in male and female rats was not increased by HCB treatment. The liver HCB concentration at 24 hr after dosing was higher in male rats than in female rats but decreased faster thereafter. These results suggest that hepatic GSH conjugation of HCB is more important in male than in female rats. This may be related to the reduced liver porphyria observed in HCB-treated male rats compared to female rats.     

Acute intravenous injection toxicity study of IBZM and BZM in rats

S-3-iodo-N-(1-ethyl-2-pyrrolidinyl)methyl-2-hydroxy-6-methoxybenzamide (IBZM) is one of the several benzamide derivatives showing a high affinity for the central nervous system (CNS) D2 dopamine receptor. Carrier-free [123I]IBZM is potentially useful as a nuclear medicine imaging agent for investigating the CNS D2 dopamine receptor in humans. This study describes the acute toxicity of IBZM and S-N-(1-ethyl-2-pyrrolidinyl)methyl-2-hydroxy-6-methoxybenzamide (BZM) in the rats. Treated rats were administered with IBZM at dose levels of 1 and 5 microg/kg and BZM at dose levels of 250 and 1250 microg/kg with dose volumes of 1 and 5 mL/kg. The control rats were administered 5 mL/kg of vehicle control. The rats were observed for 14 days. Observations included general demeanor, clinical signs, mortality, body weights/total body weight gains, and gross necropsy findings. None of the animals died during the 14-day study period. In female rats, the body weight gained at the first week of BZM treatment at a dose level of 1250 microg/kg and the total body weight gains of both IBZM treated groups were significantly higher than the control group (p < 0.05).