Experimental hepatic uroporphyria induced by the diphenyl-ether herbicide fomesafen in male DBA/2 mice

Hepatic uroporphyria can be readily induced by a variety of treatments in mice of the C57BL strains, whereas DBA/2 mice are almost completely resistant. However, feeding of the protoporphyrinogen oxidase-inhibiting herbicide fomesafen (0.25% in the diet for 18 weeks) induced hepatic uroporphyria in male DBA/2N mice (liver porphyrin content up to 150 nmol/g, control animals 1 nmol/g), whereas fomesafen-treated male C57BL/6N mice displayed only a slight elevation of liver porphyrins (approximately 5 nmol/g). The profile of accumulated hepatic porphyrins in fomesafen-treated DBA/2N mice resembled the well-characterised uroporphyria induced by polyhalogenated aromatic hydrocarbons, while histological examination confirmed the presence of uroporphyria-specific cytoplasmic inclusions in the hepatocytes. Uroporphyrinogen decarboxylase activity decreased to about 30% of control values in fomesafen-treated DBA/2N mice; microsomal methoxyresorufin O-dealkylase activity was slightly reduced. The amount of CYP1A1 and CYP1A2 mRNA, as determined by real-time PCR, was not significantly changed; mRNA encoding the housekeeping 5-aminolevulinic acid synthase was elevated 10-fold. Total liver iron was slightly increased. A similar uroporphyria was induced by the herbicide formulation Blazer, containing a structurally related herbicide acifluorfen, when fed to DBA/2N mice at a dose corresponding to 0.25% of acifluorfen in the diet. Since DBA/2 mice are almost completely resistant to all well-characterised porphyrogenic chemicals, the results suggest the possible existence of a yet unknown mechanism of uroporphyria induction, to which the DBA/2 mouse strain is more sensitive than the C57BL strain.     

Long-term genital tract changes in female mice treated neonatally with coumestrol

The neonatal mouse model has proven to be an effective system to examine long-term reproductive tract abnormalities resulting from early exposure to estrogens. Newborn C57BL/Crgl mice received 8 x 10(-2) micrograms diethylstilbestrol (DES) or 100 micrograms coumestrol (a plant estrogen) in 0.005 mL dimethyl sulfoxide (DMSO) or DMSO alone or received no treatment for the first 5 days of life. Half of the animals were ovariectomized at 40 days of age. Vaginal lavages were examined for 15 consecutive days before termination at 13 months of age, at which time genital tracts and mammary glands were removed for histological examination. Diethylstilbestrol- and coumestrol-treated animals exhibited ovary-independent persistent vaginal cornification as well as cervico-vaginal pegs and downgrowths, uterine squamous metaplasia, and an enhancement of age-related changes in the ovary including hemorrhagic follicles. In general, neonatal exposure to the naturally occurring plant estrogen, coumestrol, has long-term effects similar to those seen following exposure to natural and synthetic estrogens.     

Neurobehavioral changes in mice treated with methylmercury at two different stages of fetal development.

Pregnant C57BL/6 mice were orally given daily doses of 4 or 6 mg/kg of methylmercury chloride (MeHg) or vehicle during either gestational days 7-9 (GD7-9) or days 12-14 (GD12-14). Their female offspring were tested between 6 and 16 weeks of age on a variety of behavioral tasks. Motor coordination on the rotarod and visual discrimination learning in the Y maze were not affected by administration of MeHg either at GD7-9 or at GD12-14. In the open field, the total number of square crossings was lower in mice treated with 4 and 6 mg/kg of MeHg at GD12-14 than in control mice whether the environment was new or familiar, but prenatal administration of MeHg at GD7-9 had no effect on this measure. Administration of MeHg either at GD7-9 or at GD12-14 had no effect on the percentage of central square crossings or on the frequency of rearings in the open field. On spatial alternation training in the T maze, both treated groups in Condition GD7-9 and the group treated with 6 mg/kg at GD12-14 required more sessions to reach the learning criterion than their respective vehicle groups. When spatial alternation was tested with delays, treated groups did not differ from their respective control groups. In the radial arm maze, the performance of mice treated at GD7-9 was normal, but reference memory and working memory were impaired by administration of MeHg at GD12-14. In mice treated with 4 mg/kg of MeHg, reference memory was impaired only on the first block of trials, whereas in mice treated with 6 mg/kg, the deficit persisted on all blocks of trials. Overall, these results indicate that prenatal administration of MeHg at GD12-14 had more detrimental effects on behavioral performance than administration at GD7-9. It reduced locomotor activity and impaired reference memory for egocentric and allocentric spatial information as well as working memory for places.     

蒿甲醚引起小鼠体内日本血吸虫和曼氏血吸虫皮层变化

蒿甲醚引起小鼠体内日本血吸虫和曼氏血吸虫皮层变化１肖树华，沈炳贵，ＪａｃｋＨＯＲＮＥＲ２，ＢｒｉａｎＡＣＡＴＴＯ３（中国预防医学科学院寄生虫病研究所，世界卫生组织疟疾、血吸虫病和丝虫病合作中心，上海２０００２５，中国；２ＤｅｐａｒｔｍｅｎｔｏｆＣｌｉ...     

Immune alterations in mice exposed to the herbicide simazine

Simazine, a triazine herbicide, was investigated for its in vivo immunomodulatory properties. Male C57Bl/6 mice were treated with vehicle or 300 or 600 mg/kg body weight (bw) simazine daily orally for 4 wk. The immune system was evaluated by the antibody response to sheep red blood cells (SRBC; plaque assay and serum immunoglobulin G), natural killer (NK) and macro-phage activities, lymphocyte subpopulations in the spleen and thymus, and concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated lymphocyte proliferation using splenocytes. Body weight and spleen and thymus weight decreased generally in simazine-treated mice, while the weight of adrenal glands was higher than in the control. Simazine treatment (600 mg/kg) induced an increase in the percentage of CD4(+) cells in spleen and CD8 + in thymus. Simazine inhibited the IgM plaque-forming cell numbers and lowered the level of IgG and the proliferation of mitogen-stimulated B cells and T cells. In addition, splenic NK and peritoneal macrophage activities in exposed mice were significantly decreased. Exposure to simazine also decreased cytokine production by macrophages, such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-alpha). Taken together, data indicate that the immune system was suppressed by oral simazine exposure.     

Liver ultrastructure of dogs treated with lidoflazine for 4 years.

Lidoflazine was given orally to purebred beagle dogs for 4 yr at a dose of 10 mg/kg a day. Liver biopsy specimens from treated animals and littermate controls were examined by light and electron microscopy at the end of the study. Ultrastructurally, the livers of treated dogs had a slight increase in the number of mitochondria with crystalloids in the matrix when compared to control dog livers. All other cellular organelles appeared normal with respect to their topographic distribution, number, and morphology. In conclusion, prolonged treatment with this drug induced no observable morphologic changes reflecting impairment of normal hepatic function.     

Hepatocellular peroxisome proliferation and DNA synthesis in Wistar rats treated with herbicide fluazifop

The aim of this study was to determine the effect of herbicide fluazifop, on the early occurring changes in rat liver regarded as hepatic markers of peroxisome proliferators (PPs). Fluazifop was administered orally to male Wistar rats at increasing doses from 5.6 to 891 mg/kg body weight per day for 1, 2, 4, 7 and 14 consecutive days and peroxisome proliferation, induction of some peroxisome-associated enzymes and mitogenesis (S-phase, M-phase and percentage of binucleated hepatocytes) were studied. Short-term treatment of rats with fluazifop resulted in hepatomegaly due to time dependent proliferation of smooth endoplasmic reticulum (SER) and peroxisomes. The increase in the number of peroxisomes in the hepatocytes was supported by an increase in peroxisomal palmitoyl-CoA oxidation and catalase activity. In contrast to other PPs fluazifop induced low rate of rcplicative DNA synthesis and did not affect mitoses (M-phase). DNA synthesis was accompanied by the appearance of binucleated hepatocytes. Thus, we can conclude that fluazifop produces in male Wistar rats hepatomegaly due to cellular hypertrophy. The threshold dose for palmitoyl-CoA oxidation and DNA synthesis was 112 and 223 mg/kg body weight per day, respectively. The value for hepatomegaly and catalase activity was 56 mg/kg body weight per day. The results presented in this paper demonstrated that fluazifop can be classified as a weak rodent PPs.     

Tissue glutathione levels in mice treated with delta-9-tetrahydrocannabinol.

Glutathione (GSH) is widely distributed among living cells and is involved in many biological functions. It provides the sulfhydryl groups for conjugation of toxic metabolites of several xenobiotica. Acetaminophen (Tylenol) toxicity is a classical example of this property. For this purpose, we studied the effects of delta-9-tetrahydrocannabinol (THC) on tissue levels of GSH in the mice. Groups of male Swiss Webster mice weighing 25 +/- 5 g were treated with 50 mg/kg, PO THC at 1300 h. Control mice were given equal volume of sesame oil (5 ml/kg, PO) which was the vehicle for THC. Ninety minutes following THC administration, mice were sacrificed, their plasma, brain, heart, liver, kidney and testis were collected. All tissues were homogenized in 5% TCA/EDTA solution and supernatant solutions of these homogenates were diluted. In these diluted samples, levels of GSH were determined by a modified spectrophotometric procedure and the GSH levels were expressed as micromoles of GSH/g tissue. In this study, THC caused no effects on GSH levels in brain, heart, testis and plasma. However, GSH levels in liver and kidney were decreased by 14% and 7% respectively. Although the decrease in kidney GSH levels were insignificant, these changes in liver and kidney could be indicative of a possible metabolic and/or dispositional interaction between THC and different commonly available drugs such as acetaminophen.     

Prolonged vaginal cornification and other changes in mice treated neonatally with coumestrol, a plant estrogen

This study used the neonatal mouse model to determine if early exposure of female mice to coumestrol, a plant estrogen, would result in reproductive-tract alterations similar to those seen after neonatal exposure to diethylstilbestrol (DES). Newborn female C57BL/Crgl mice were given daily subcutaneous injections of 0.08 micrograms DES or 100 micrograms coumestrol in 0.005 ml dimethyl sulfoxide (DMSO), or DMSO alone, or were untreated, for the first 5 d of life. The doses chosen were equivalent in biological activity based on published uterine bioassay data (using young adult mice). Observations were made twice daily for 1.5 mo to determine the times of eye and complete vaginal opening. Half of the animals were ovariectomized at 40 d of age. Vaginal lavages were examined for 30 consecutive d beginning both at 2 and at 5 mo of age. DES and coumestrol significantly advanced the time of complete vaginal opening and induced a comparable degree of ovary-independent persistent vaginal cornification. In addition, coumestrol resulted in the occurrence of hemorrhagic ovarian follicles.     

Histopathology of testes from mice chronically treated with cobalt.

Effects of cobalt on murine testes were evaluated by light and electron microscopy. Continuous exposure of male mice to cobalt (400 ppm) via drinking water over a 13-week period resulted in a reproducible, sequential pattern of seminiferous tubule degeneration. Initial changes involved vacuolation of Sertoli cells and formation of abnormal spermatid nuclei. This was followed by the presence of multinucleated cells and sloughing of cells. Sertoli cells phagocytosed degenerating cells. Continued degeneration resulted in shrinkage of tubules with the accumulation of "calcified" necrotic debris in some. Sertoli cells were the last surviving cells. As degenerating tubules shrank, peritubular areas became highly disorganized. Myoid cell shapes became irregular, and basal laminae became highly folded. Endothelial cells of testicular vessels were thickened in areas and contained vesiclelike structures. Leydig cell morphology was normal but interstitial areas appeared hypercellular. The possible interactions of cobalt with iron and zinc, essential metals for spermatogenesis, are discussed.     

Reproductive changes in male rats treated perinatally with an aromatase inhibitor.

The effects of maternal exposure to aromatase inhibitor during the perinatal period of sexual brain differentiation were studied. The fertility was assessed in adult, male rat offspring of aromatase inhibitor-treated dams. The following results were obtained: (1) Sexual maturation, body weight, and wet weights of testis, pituitary, seminal vesicle, ventral prostate, and levatori ani muscle were unchanged at adult life. (2) Fifty percent of the animals were able to mate with normal females, which became pregnant but exhibited an increased number of preimplantation loss. (3) There was a decrease in the number of spermatozoa found in the testes and in the daily sperm production. (4) Of those, 25% of the male rats treated with aromatase inhibitor did not present male sexual behavior, showing female behavior when pretreated with estrogen. These results indicate that perinatal exposure to aromatase inhibitor during the critical period of male brain sexual differentiation has a long-term effect on the reproductive physiology and behavior of male rats.     

Modulation of apoptosis in mice treated with Echinacea and St. John's wort.

Apoptosis, or programmed cell death (PCD), is a physiological active cellular suicide process that occurs in non-contiguous cells, and is usually not associated with inflammation. The apoptotic process can be modulated by various stimuli, including hormones, cytokines, growth factors, and some chemotherapeutic agents. To determine whether Echinacea purpurea and Hypericum perforatum are able to regulate the process of apoptosis in vivo and to define the role of the Fas-Ag and Bcl-2 signal transduction cascade, we have orally treated groups of mice with these vegetable drugs for 14 days. The splenic lymphocytes from mice treated with E. purpurea and H. perforatum at the two dose levels used (30 and 100 mg kg(-1) per day) were shown to be significantly more resistant to apoptosis than those from mice treated only with the vehicle. In addition, mice treated with the natural substances showed a decrease in Fas-Ag expression and an increase in Bcl-2 expression. In conclusion, our results shown that in vivo the studied drugs modulate apoptosis in mice splenic lymphocytes and that this action could be mediated in part by a decrease in Fas-Ag expression and in part by an increase in Bcl-2 expression.     

Dietary zinc deficiency predisposes mice to the development of preneoplastic lesions in chemically-induced hepatocarcinogenesis

Although there is a concomitance of zinc deficiency and high incidence/mortality for hepatocellular carcinoma in certain human populations, there are no experimental studies investigating the modifying effects of zinc on hepatocarcinogenesis. Thus, we evaluated whether dietary zinc deficiency or supplementation alter the development of hepatocellular preneoplastic lesions (PNL). Therefore, neonatal male Balb/C mice were submitted to a diethylnitrosamine/2-acetylaminefluorene-induced hepatocarcinogenesis model. Moreover, mice were fed adequate (35 mg/kg diet), deficient (3 mg/kg) or supplemented (180 mg/kg) zinc diets. Mice were euthanized at 12 (early time-point) or 24 weeks (late time-point) after introducing the diets. At the early time-point, zinc deficiency decreased Nrf2 protein expression and GSH levels while increased p65 and p53 protein expression and the number of PNL/area. At the late time-point, zinc deficiency also decreased GSH levels while increased liver genotoxicity, cell proliferation into PNL and PNL size. In contrast, zinc supplementation increased antioxidant defense at both time-points but not altered PNL development. Our findings are the first to suggest that zinc deficiency predisposes mice to the PNL development in chemically-induced hepatocarcinogenesis. The decrease of Nrf2/GSH pathway and increase of liver genotoxicity, as well as the increase of p65/cell proliferation, are potential mechanisms to this zinc deficiency-mediated effect.     

Neuropsychological changes in demented patients treated with acetyl-L-carnitine

The study was carried out on 24 patients suffering from mild to moderate dementia. The diagnosis of dementia was made according to DMS III criteria. Patients with cerebrovascular pathologies were excluded by using Hachinski Ischaemic Score less than or equal to 4 and computerized tomography parameters. Patients with depression (Hamilton Rating Scale for Depression greater than or equal to 18) were excluded. All the patients, after a wash-out period of two weeks were treated on a simple blind method with acetyl-L-carnitine (No. = 12 patients) and piracetam (12 patients) by intravenous route (two weeks) followed by an oral one for further 10 weeks. A battery of clinical neuropsychological tests was applied to evaluate the cognitive, attentive and behavioural aspects. The results, analysed by non-parametric variance analysis (Friedman Test) show a statistically significant improvement of the behavioural profile, of attention and of psychomotricity in the patients treated with acetyl-L-carnitine. No significant improvement was found in the piracetam group.     

Pigmentary changes in a patient treated with imatinib

Imatinib mesylate (STI 571; Gleevec; Novartis Pharmaceuticals, Basel, Switzerland) is an orally available tyrosine kinase inhibitor that targets a constitutively activated BCR-ABL tyrosine kinase with additional inhibitory effects on platelet derived growth factor (PDGF) receptors alpha and beta, and KIT. It has revolutionized the treatment of adult and pediatric patients with Philadelphia chromosome positive chronic myelogenous leukemia (CML) and is also FDA-approved for KIT-positive advanced gastrointestinal tumor (GIST) and dermatofibrosarcoma protuberans. A wide spectrum of dermatologic toxicities has been associated with this agent, among which a maculopapular rash is the most common event. In addition, a variety of pigmentary abnormalities of the skin and mucosal surfaces have been reported. Hypopigmentation is a well-recognized adverse effect. In contrast, paradoxical hyperpigmentation has only rarely been documented. In this case report we describe imatinib-induced cutaneous hyperpigmentation and graying of hair occurring in the same patient with dermatofibrosarcoma protuberans treated with imatinib.