Pathological Study of Demyelination with Cellular Reactions in the Cerebellum of Dogs Infected with Canine Distemper Virus.

The purpose of this study was to examine the relationship between demyelination and cellular reactions in the cerebellum of Canine Distemper Virus (CDV)-infected dogs. We subdivided the disease staging by adding the degree of demyelination determined by Luxol Fast Blue staining to the previously reported disease staging from the acute stage to the chronic stage, and investigated the relationship between demyelination in the cerebellum and the number and histological changes in astroglia, microglia, and Purkinje cells in each stage. Reactions of astrocytes and microglia were observed at an early stage when demyelination was not evident.

Droplet Digital PCR Enhances Sensitivity of Canine Distemper Virus Detection.

Canine distemper virus (CDV) poses a substantial threat to diverse carnivorans, leading to systemic and often fatal diseases. Accurate and prompt diagnosis is paramount for effective management and curbing further transmission. This study evaluates the diagnostic performance of droplet digital PCR (ddPCR) in comparison to conventional reverse-transcription (RT-PCR) and quantitative reverse-transcription real-time PCR (RT-qPCR).

Histopathological Analysis of Brains from Dogs Infected with Canine Distemper Virus.

We describe the use of conventional histology and immunohistochemistry against canine distemper virus (CDV) to examine the brains of domestic dogs with a confirmed diagnosis of CDV infection. Histologically, to identify the main typical lesions, we used conventional H&E stain; to evaluate the progressive demyelination, we used Luxol Fast Blue stain; and to identify the presence of viral particles in these affected regions, we used immunohistochemistry against CDV. We confirm that the histopathological analysis of brains of distemper-infected dogs is a powerful tool to evaluate the typical brain lesions and could be used as an interesting natural model to continue studying the pathogenesis of canine distemper in different species and/or other morbillivirus infections, like measles.

Central nervous system lesions caused by canine distemper virus in 4 vaccinated dogs.

We examined the cerebellum and cerebrum of 4 vaccinated dogs, 3-60-mo-old, that displayed clinical signs of canine distemper virus (CDV) infection, and died 7-40 d after developing neurologic signs. The main histologic lesions were demyelination, gliosis, meningitis, perivascular lymphocytic cuffing, and inclusion bodies. These lesions were similar in all 4 cases regardless of the time since vaccination, except that meningoencephalitis and gliosis were subacute in 3 dogs and chronic in 1 dog.

Subcutaneous extraskeletal chondroblastic osteosarcoma in a cat.

Case Summary: An 11-year-old neutered male cat was presented with a fixed, subcutaneous mass in the left hindlimb. The neoplasm was surgically removed and determined to be a 2 × 2 × 9 cm mass that extended over the plantar surface of the left hindlimb from the tarsus to the phalanges. It was independent from the skeletal system but firmly attached to the adjacent connective tissue.

Risk assessment study of dioxins in sanitary napkins produced in Japan.

A risk assessment study of dioxins in sanitary napkins produced in Japan was performed. The daily estimated exposure volume to dioxins was compared with the tolerable daily intake (TDI). The concentrations of dioxins such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) in seven sanitary napkins were measured using gas chromatography and mass spectroscopy analytical methods.

Correlation study in skin and eye irritation between rabbits and humans based on published literatures.

The purpose of this study was to investigate the correlations in skin and eye irritations between rabbits and humans using published international databases. We selected 60 and 56 compounds for skin and eye irritation, respectively. When the reactions were divided into irritation-negative or irritation-positive, including corrosion, similar reactions between rabbits and humans were detected for 53 compounds in skin irritation and 54 compounds in eye irritation, showing rates of agreement in skin and eye as 88% and 96%, respectively.

Endocrine-mediated effects of two benzene related compounds, 1-chloro-4-(chloromethyl)benzene and 1,3-diethyl benzene, based on subacute oral toxicity studies using rats.

The purpose of this study was to investigate the endocrine-mediated effects of the benzene-related compounds with reference to Organization for Economic Co-operation and Development (OECD) Test Guideline No. 407. Rats were orally gavaged with 0, 10, 50, and 250 mg/kg/day of 1-chloro-4-(chloromethyl)benzene, and 0, 25, 150, and 1000 mg/kg/day of 1,3-diethyl benzene for at least 28 days, beginning at 8 weeks of age.

Comparison of endocrine-mediated effects of two bisphenol A related compounds, 2,2-bis(4-cyanatophyenyl)propane and 4,4'-cyclohexylidenebisphenol, based on subacute oral toxicity studies using rats.

The purpose of this study was to compare endocrine-mediated effects of bisphenol A related compounds, 2,2-bis(4-cyanatophyenyl)propane and 4,4'-cyclohexylidenebisphenol with reference to OECD Test Guideline No. 407. Rats were orally gavaged with 0, 4, 20, and 100 mg/kg/day of 2,2-bis(4-cyanatophyenyl)propane, and 0, 30, 100, and 300 mg/kg/day of 4,4'-cyclohexylidenebisphenol for at least 28 days beginning at 8 weeks of age.

Endocrine-mediated effects of 4,4'-(hexafluoroisopropylidene)diphenol in SD rats, based on a subacute oral toxicity study.

The purpose of this study was to investigate the endocrine-mediated effects of 4,4'-(hexafluoroisopropylidene)diphenol according to OECD test guideline no. 407. The estrogenic properties of this chemical have already been shown on uterotrophic assay, and this chemical is classified as a low-production volume chemical in REACH program.

Enhanced OECD TG 407 in detection of endocrine-mediated effects of 4,4'-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol.

The purpose of this study was to investigate whether the estrogenic effects were detected in the enhanced TG 407 if the estrogenic property was not so strong in the uterotrophic assay. The estrogenic property of 4,4'-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol in the uterotrophic assay was slightly stronger than that of genistein or nonylphenol, but weaker than that of ethinyl estradiol. We performed a 28-day repeated-dose toxicity study (enhanced OECD test guideline No.

Effects of in utero through lactational exposure to dicyclohexyl phthalate and p,p'-DDE in Sprague-Dawley rats.

Anti-androgenic chemicals alter sexual differentiation by a variety of mechanisms, and the mechanisms between phthalate esters and p,p'-DDE are considered to be different. We performed an in utero through lactational exposure assay using dicyclohexyl phthalate and p,p'-DDE to investigate the sexual differentiation of these chemicals. Pregnant CD (SD) IGS rats were given dicyclohexyl phthalate or p,p'-DDE orally from gestational day (GD) 6 to postnatal day (PND) 20, and the endocrine-mediated effects in dams and their offspring were examined.

Uterotrophic assay, Hershberger assay, and subacute oral toxicity study of 3-amino-1,2,4-triazole based on the Organization for Economic Co-operation and Development draft protocols.

We performed a uterotrophic assay, the Hershberger assay, and the 28-day repeated-dose toxicity study (enhanced OECD test guideline no. 407) of 3-amino-1,2,4-triazole based on the OECD draft protocols. In the uterotrophic assay, female SD rats were subcutaneously injected with the chemical at doses of 0, 100, 300, and 1,000 mg/kg on each of 3 days from postnatal day 20 to day 22, and no changes were observed.

The inhalation exposure of carbon tetrachloride promote rat liver carcinogenesis in a medium-term liver bioassay.

The potential of carbon tetrachloride (CCl4) to induce pre-neoplastic lesions in rat liver using a medium-term liver assay (Ito method) for the prediction of carcinogenicity was examined by nose-only inhalation exposure of male rats (15/group) to CCl4 vapor at concentrations of 0, 1, 5, 25, 125 ppm for 6h/day, 6 day/week, for a period of 6 weeks. The numbers and area of glutathione S-transferase placental (GST-P) positive foci were then determined. Additionally, other histopathological observations on the livers were recorded and serum chemical parameters and CCl4 concentrations in blood were measured.

Uterotrophic assay, Hershberger assay, and subacute oral toxicity study of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol) and 3-(dibutylamino)phenol, based on the OECD draft protocols.

We performed a uterotrophic assay, the Hershberger assay, and a 28-day repeated-dose toxicity study [enhanced Organization for Economic Co-operation and Development (OECD) test guideline No. 407] of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol) and 3-(dibutylamino)phenol, based on the OECD draft protocols. In the uterotrophic assay of 4,4'-butylidenebis(2-tert-butyl-5-methylphenol), female SD rats were subcutaneously injected with the chemical at doses of 0, 100, 300, and 1,000 mg/kg on each of 3 days from postnatal day 20 to day 22, and no changes were observed.

Relationship between the results of in vitro receptor binding assay to human estrogen receptor alpha and in vivo uterotrophic assay: comparative study with 65 selected chemicals.

For screening chemicals possessing endocrine disrupting potencies, the uterotrophic assay has been placed in a higher level in the OECD testing framework than the ER binding assay to detect ER-mediated activities. However, there are no studies that can demonstrate a clear relationship between these assays. In order to clarify the relationship between the in vitro ER binding and in vivo uterotrophic assays and to determine meaningful binding potency from the ER binding assay, we compared the results from these assays for 65 chemicals spanning a variety of chemicals classes.

Subacute oral toxicity study of bisphenol F based on the draft protocol for the "Enhanced OECD Test Guideline no. 407".

Since bisphenol F (4,4'-dihydroxydiphenylmethane) has been reported to exhibit estrogen agonistic properties in the uterotrophic assay, we performed a 28-day repeated-dose toxicity study (enhanced OECD test guideline No. 407) on bisphenol F based on the OECD draft protocols to determine whether it has endocrine-mediated properties. Bisphenol F was orally administered at doses 0, 20, 100 and 500 mg/kg per day for at least 28 days, but no clear endocrine-mediated changes were detected, and it was concluded to have no endocrine-mediated effects in young adult rats.

The OECD program to validate the rat Hershberger bioassay to screen compounds for in vivo androgen and antiandrogen responses: phase 2 dose-response studies.

Objective: The Organisation for Economic Co-operation and Development (OECD) has completed phase 2 of an international program to validate the rodent Hershberger bioassay.

Design: The Hershberger bioassay is designed to identify suspected androgens and antiandrogens based on changes in the weights of five androgen-responsive tissues (ventral prostate, paired seminal vesicles and coagulating glands, the levator ani and bulbocavernosus muscles, the glans penis, and paired Cowper's or bulbourethral glands). Protocol sensitivity and reproducibility were tested using two androgen agonists (17alpha-methyl testosterone and 17beta-trenbolone), four antagonists [procymi-done, vinclozolin, linuron, and 1,1-dichoro-2,2-bis-(p-chlorophenyl)ethylene (p,p'-DDE)], and a 5alpha-reductase inhibitor (finasteride).

Uterotrophic assay, Hershberger assay, and subacute oral toxicity study of 4,4 -[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bis[phenol] based on the OECD draft protocols.

We performed an uterotrophic assay, the Hershberger assay, and a 28-day repeated-dose toxicity study (enhanced OECD test guideline No. 407) of 4,4 -[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bis[phenol] based on the OECD draft protocols. In the uterotrophic assay, female SD rats were subcutaneously injected with the chemical at doses of 0, 100, 300, and 1,000 mg/kg on each of 3 days from postnatal day 20 to day 22, and the uterine weight of rats given the 1,000 mg/kg dose of the test chemical plus ethinyl estradiol decreased.

Two-generation reproductive toxicity studies in rats with extra parameters for detecting endocrine disrupting activity: introductory overview of results for nine chemicals.

Two-generation reproductive toxicity studies using rats of benzophenone, n-butylbenzene, butyl benzyl phthalate, 2,4-dichlorophenol, dicychlohexyl phthalate, diethyl phthalate, 4-nitrotoluene, lindane and vinclozolin, were performed to investigate whether these chemicals have endocrine-mediated effects with the support of the Ministry of Economy, Trade and Industry and the Ministry of the Environment. Benzophenone exposure was via the diet at concentrations of 0, 100, 450 or 2000 ppm, n-butylbenzene was administered orally by gavage at dose levels of 0, 30, 100 or 300 mg/kg/day, butyl benzyl phthalate was administered orally by gavage at dose levels of 0, 100, 200, or 400 mg/kg/day, 2,4-dichlorophenol was administered in the diet at concentrations of 0, 500, 2000 or 8000 ppm, dicyclohexyl phthalate was given in the diet at concentrations of 0, 240, 1200 or 6000 ppm, diethyl phthalate was administered in the diet at concentrations of 0, 600, 3000 or 15000 ppm, 4-nitrotoluene was administered orally by gavage at doses of 0, 40, 80, or 160 mg/kg/day, lindane exposure was in the diet at concentrations of 0, 10, 60, or 300 ppm, and vinclozolin treatment was by feeding diet at concentrations of 0, 40, 200 or 1000 ppm.

OECD validation of the Hershberger assay in Japan: Phase 3. Blind study using coded chemicals.

The Organization for Economic Co-operation and Development (OECD) has initiated the development of new guidelines for the screening and testing of potential endocrine disrupters. The Hershberger assay is one of the assays selected for validation based on the need for in vivo screening to detect androgen agonists or antagonists by measuring the response of five sex accessory organs and tissues of castrated juvenile male rats: the ventral prostate, the seminal vesicles with coagulating glands, the levator ani and bulbocavernosus muscle complex (LABC), Cowper's glands, and the glans penis. The Phase 1 feasibility demonstration stage of the Hershberger validation program has been successfully completed with a single androgen agonist and a single antagonist as reference substances.

Advantage of using CBA/N strain mice in a non-radioisotopic modification of the local lymph node assay.

The murine local lymph node assay (LLNA) is currently recognized as a stand-alone test method for determining the skin sensitizing potential of chemicals. It has been incorporated into the official test guidelines published by some authorities, including the OECD. To avoid the use of radioisotopes, efforts have been made recently to develop non-radioisotopic modifications of the LLNA.

Subacute oral toxicity study of di(2-ethylhexyl)adipate based on the draft protocol for the "Enhanced OECD Test Guideline no. 407".

We performed a 28-day repeated-dose toxicity study of di(2-ethylhexyl)adipate (DEHA) based on the draft protocol of the "Enhanced OECD Test Guideline 407" to investigate whether it has endocrine-mediated properties according to this assay. DEHA was orally administered to SD rats at doses of 0, 40, 200 and 1,000 mg/kg/day for at least 28 days, and disturbance of the estrous cycle and increased ovarian follicle atresia were detected in the 1,000 mg/kg group.

Subacute oral toxicity study of diethylphthalate based on the draft protocol for "Enhanced OECD Test Guideline no. 407".

We performed a 28-day repeated-dose toxicity study of diethylphthalate based on the draft protocol of the "Enhanced OECD Test Guideline 407" to investigate whether it has endocrine-mediated properties according to this assay. Diethylphthalate was orally administered to SD rats at doses of 0, 40, 200, and 1,000 mg/kg/day for at least 28 days, but no endocrine-mediated effects were detected based on any of the parameters examined, suggesting that diethylphthalate does not possess endocrine properties according to this assay.

Ability of the Hershberger assay protocol to detect thyroid function modulators.

In vivo screening methods for detection of thyroid function modulators are now under development in many research laboratories. We assessed the applicability of the Hershberger assay protocol to screen for thyroid function modulators. In experiment 1, castrated male BrlHan WIST@Jcl (GALAS) rats were administered a potent thyroid peroxidase inhibitor, 3-amino-1,2,4-triazole (AT), in doses of 0, 40, 200, and 1,000 mg/kg/day with gravimetric endpoint, and in experiment 2, castrated and intact male rats were administered in doses of 0, 40, and 200 mg/kg/day, with quantification of the extent of hypertrophy of the thyroid epithelium, to assess the effects of castration, by gavage to 8-week-old for 10 consecutive days.