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Osteoporosis is a prevalent metabolic bone disease. While drug therapy is essential to prevent bone loss in osteoporotic patients, current treatments are limited by side effects and high costs, necessitating the development of more effective and safer targeted therapies. Utilizing a zebrafish ( Danio rerio ) larval model of osteoporosis, we explored the influence of the metabolite spermine on bone homeostasis. Results showed that spermine exhibited dual activity in osteoporotic zebrafish larvae by increasing bone formation and decreasing bone resorption. Spermine not only demonstrated excellent biosafety but also mitigated prednisolone-induced embryonic neurotoxicity and cardiotoxicity. Notably, spermine showcased protective attributes in the nervous systems of both zebrafish embryos and larvae. At the molecular level, Rac1 was identified as playing a pivotal role in mediating the anti-osteoporotic effects of spermine, with P53 potentially acting downstream of Rac1. These findings were confirmed using mouse ( Mus musculus ) models, in which spermine not only ameliorated osteoporosis but also promoted bone formation and mineralization under healthy conditions, suggesting strong potential as a bone-strengthening agent. This study underscores the beneficial role of spermine in osteoporotic bone homeostasis and skeletal system development, highlighting pivotal molecular mediators. Given their efficacy and safety, human endogenous metabolites like spermine are promising candidates for new anti-osteoporotic drug development and daily bone-fortifying agents.

Using diagnostic data and contemporary sampling efforts, we conducted surveillance for a diversity of pathogens, toxicants, and diseases of muskrats (Ondatra zibethicus). Between 1977 and 2019, 26 diagnostic cases were examined from Kansas and throughout the Southeast and Mid-Atlantic, USA. We identified multiple causes of mortality in muskrats, but trauma (8/26), Tyzzer's disease (5/6), and cysticercosis (5/26) were the most common. We also conducted necropsies, during November 2018-January 2019 Pennsylvania muskrat trapping season, on 380 trapper-harvested muskrat carcasses after the pelt was removed. Tissue samples and exudate were tested for presence of or exposure to a suite of pathogens and contaminants. Gastrointestinal tracts were examined for helminths. Intestinal helminths were present in 39.2% of necropsied muskrats, with Hymenolepis spp. (62%) and echinostome spp. (44%) being the most common Molecular testing identified a low prevalence of infection with Clostridium piliforme in the feces and Sarcocystis spp. in the heart. We detected a low seroprevalence to Toxoplasma gondii (1/380). No muskrats were positive for Francisella tularensis or Babesia spp. Cysticercosis was detected in 20% (5/26) of diagnostic cases and 15% (57/380) of our trapper-harvested muskrats. Toxic concentrations of arsenic, cadmium, lead, or mercury were not detected in tested liver samples. Copper, molybdenum, and zinc concentrations were detected at acceptable levels comparative to previous studies. Parasite intensity and abundance were typical of historic reports; however, younger muskrats had higher intensity of infection than older muskrats which is contradictory to what has been previously reported. A diversity of pathogens and contaminants have been reported from muskrats, but the associated disease impacts are poorly understood. Our data are consistent with historic reports and highlight the wide range of parasites, pathogens and contaminants harbored by muskrats in Pennsylvania. The data collected are a critical component in assessing overall muskrat health and serve as a basis for understanding the impacts of disease on recent muskrat population declines., Competing Interests: The authors have declared that no competing interests exist.

Air pollution has been associated with neuroinflammatory processes and is considered a risk factor for the development of neurodegenerative diseases. Volcanic environments are considered a natural source of air pollution. However, the effects of natural source air pollution on the central nervous system (CNS) have not been reported, despite the fact that up to 10% of the world's population lives near a historically active volcano. In order to assess the response of the CNS to such exposure, our study was conducted in the island of Sao Miguel (Azores, Portugal) in two different areas: Furnas, which is volcanically active one, and compared to Rabo de Peixe, a reference site without manifestations of active volcanism using Mus musculus as a bioindicator species. To evaluate the state of the astroglial population in the dentate gyrus in both samples, the number of astrocytes was determined using immunofluorescence methods (anti-GFAP and anti-GS). In addition, the astrocytic branches in that hippocampal area were examined. Our results showed an increase in GFAP+ astrocytes and a reduction in GS+ astrocytes in Furnas-exposed mice compared to animals from Rabo de Peixe. In addition, astrocytes in the dentate gyrus of chronically exposed animals exhibited longer branches compared to those residing at the reference site. Thus, reactive astrogliosis and astrocyte dysfunction are found in mice living in an active volcanic environment.

A mortality event of nine threatened smoky mice (Pseudomys fumeus) occurred in January 2020 at a captive breeding facility in southeastern Australia that was affected at the time by hazardous levels of bushfire smoke, despite being more than 20 km from the nearest fire. Pathologic and clinical observations indicated smoke inhalation was the cause of death. All animals had significant pulmonary lesions, notably pulmonary edema and congestion, and moderate amounts of dark brown to black pigmented intracellular and extracellular particles from <0.5-2.5 µm in diameter were observed in the central or hilar region of the lungs of four of six animals examined histologically. Deaths occurred between three and 30 d after exposure to smoke and, for seven animals in outdoor acclimatization enclosures, were associated with very high ambient temperature (>40 C). Similar mortalities did not occur in co-located parrots, suggesting differing species sensitivity to smoke inhalation. Our findings highlight the potential for smoke to be an underdiagnosed cause of mortality in free-ranging wildlife during bushfires and for bushfires to affect wildlife populations outside of burnt areas, including in unburnt refugia. Conservation interventions for wildlife after bushfires should consider and, where possible, mitigate the risk of animals dying due to increased respiratory demand following smoke inhalation injury., (© Wildlife Disease Association 2021.)

An 8 yr, intact male red-rumped agouti ( Dasyprocta leporina) was evaluated for weight loss. Examination revealed poor body condition, hypercalcemia, elevated serum 25-hydroxyvitamin D, metastatic calcification of soft tissues, and hyperechoic kidneys. The diet, formulated for laboratory rodents, contained elevated levels of vitamin D 3 . Histopathology from a female conspecific that died 5 mo prior identified dystrophic mineralization and nephrosclerosis, suggestive of a vitamin D 3 toxicity. The male agouti responded well to a dietary reduction in vitamin D 3 and calcium. Six months into therapy, progressive renal failure was identified and was further managed with enalapril, phosphorus binders, and dietary manipulation. Suspected vitamin D 3 toxicity has been reported in pacas ( Cuniculus paca) and agouti and has been linked to exposure to New World primate diets. In this brief communication, an agouti developed suspected hypervitaminosis D after receiving a commercial rodent diet commonly fed to this species in captivity.

Time-weighted exposure limits to ammonia are established for humans; however similar guidelines have not been defined for laboratory rodents. The Guide recommends maintaining air pollutants at concentrations below levels irritating to mucous membranes but does not provide specific values. Numerous studies have examined ammonia and its effects on animal health, yet none have assessed the effects of naturally occurring intracage ammonia on the lower pulmonary tree and pulmonary endothelial and epithelial integrity in mice. We performed several assays commonly used in mouse acute lung-injury studies (bronchoalveolar lavage fluid [BAL] cell counts and protein concentration, excess lung water content [ELW], Evans blue permeability assay [EBA], lung tissue myeloperoxidase assay [MPO], and lung histopathology) to evaluate the effects of exposure to cyclical, naturally occurring ammonia levels on pulmonary integrity and inflammation. C57BL/6 mice were maintained in static microisolation or open-top cages. Cages were changed weekly, and ammonia levels were measured for 6 wk on days 0, 1, 3, 5, and 7 of each cage-change cycle. Ammonia levels in static microisolation cages began to increase on day 3 and peaked at a mean of 141.3 ppm on day 7. Ammonia levels in open-top cages never exceeded 5 ppm. Neither BAL cell counts, protein concentration, ELW, EBA, nor MPO differed significantly between groups. Lung histopathology showed minimal, incidental changes in all mice. Our findings indicate that the ammonia concentrations in the static microisolation cages we used did not alter the integrity of the lower pulmonary tract nor influence key indicators used to assess acute lung injury.

Carbon dioxide is the most commonly used gas for euthanasia of rodents. The current AVMA Guidelines recommend slowly filling the container with CO2 (SF) and now indicate that the practice of placing conscious animals in containers prefilled with CO2 (PF) is unacceptable. An investigator noted pulmonary hemorrhage (PH) in BALB/c mice euthanized by SF that was not observed after PF. Here we evaluated whether the air-displacement rate (SF compared with PF) influenced the development of PH or nasal hemorrhage (NH) in 2 commonly used mouse strains. In addition, we investigated the prevalence of PH and NH in mice euthanized by isoflurane overdose (IO). Male and female (age groups, 6 wk and 6 mo) BALB/c and C57BL/6 mice were euthanized by SF or PF. In addition, 6-mo-old BALB/c male mice were euthanized by IO. Lung, nasal turbinates, brain, and reproductive organs were collected for gross and histologic evaluation and scored for degree of hemorrhage (score, 0 to 3). Severity of hemorrhage did not differ according to mouse age or sex. PH in BALB/c mice was more severe after SF than PF, and SF and PF induced more severe PH in BALB/c than in C57BL/6 mice. PH in 6-mo-old male BALB/c mice was more severe after SF than IO. Neither SF, PF, nor IO influenced the prevalence of NH in any group. This study demonstrates that the method of euthanasia may need to be altered depending on the mouse strain used.

Introduction: We investigated the 2-year survival rate and incidence of spontaneous tumors in F344/DuCrlCrlj rats used in carcinogenicity studies of chemical substances. Records for animals used in the control groups of carcinogenicity studies which were conducted during the last 10 years were obtained from the database of the Japan Bioassay Research Center (JBRC). Six hundred ninety-nine males and 550 females were used in 14 and 11 inhalation studies, respectively, and 500 animals of each sex were used in 10 male and 10 female oral studies., Methods: In each study, SPF (specific pathogen free) animals were housed for 2 years (104 weeks) as control groups in the carcinogenicity studies. All animals underwent necropsy and histopathological examination. Each study was conducted in accordance with the Good Laboratory Practice., Results: The incidence of interstitial cell tumors was highest in both inhalation studies and oral studies (inhalation studies 86.1%, oral studies 68.6%). Tumors which had an incidence of 6% or higher were adenoma of the pituitary, C-cell adenoma of the thyroid, and mononuclear cell leukemia (LGL leukemia) of the spleen in male and female rats; fibroma of the subcutaneous tissue, adrenal pheochromocytoma, and islet cell adenoma of the pancreas in male rats; and endometrial stromal polyps and fibroadenoma of the mammary gland in female rats. Tumors other than the above had rare incidence rates. A clear difference in the incidence of spontaneous tumors was not observed between the inhalation and oral studies. The incidences of spontaneous tumors in control groups of previous oral studies are similar to our findings. There are no other reports of the spontaneous tumor incidence in the control groups of inhalation studies using F344/DuCrlCrlj rats. The 2-year survival rate was about 77% in both the inhalation and oral studies, and a gender difference was not observed. The F344/DuCrlCrlj rats used at JBRC had a higher 2-year survival rate than F344/N rats. This difference is possibly due to the low incidence of LGL leukemia in the F344/DuCrlCrlj rat., Conclusions: The incidences of spontaneous tumors in F344/DuCrlCrlj rats used in control groups of both inhalation and oral studies during the last 10 years at JBRC are similar to each other and similar to those reported in other studies. This is the first report on the incidence of spontaneous tumors in inhalation studies and contributes to the toxicological evaluation of studies using F344/DuCrlCrlj rats.

Introduction: Chronic psychological distress can cause suppression of the hypothalamic-pituitary-testicular axis and thus lead to male hypogonadism, which is associated with psycho-social dysfunction, chronic diseases, and as a result, considerable economic costs. Conversely, noise is a prototypal environmental stressor of growing importance, already linked to birth outcomes and diabetes. However, its effects on male testosterone levels have been paid little attention., Material and Methods: This paper reports a systematic review and meta-analysis of experimental studies in rodents, which have examined the effect of chronic noise stress on serum testosterone levels. A systematic search in MEDLINE, EMBASE and the Internet yielded seven studies. A quality effects meta-analytical model was applied to compute pooled Hedges's g. Quality effects meta-regression was carried out as well., Results: We found pooled Hedges's g of -2.41 (95% CI: -3.28, -1.54), indicating a very large effect of noise exposure on testosterone. Metaregression confirmed that the overall duration of exposure explained a significant proportion of the variance across individual effect sizes (Q (1) = 3.95, p = 0.047). However, there was considerable inter-study heterogeneity (I2 = 82%) and publication bias (p = 0.016). After inputting two studies previously thought to be missing, the pooled effect dropped to g = -1.53 (95% CI: -3.01, -0.05)., Conclusions: Chronic noise exposure of ≈ 100 dB leads to a significant reduction of serum testosterone in male rodents. Research on humans is highly warranted, especially given the steady trend in Western societies for increasing the burden of both male hypogonadism and noise pollution.

Oral administration of non-steroidal anti-inflammatory drugs (NSAIDs) can lead to adverse effects such as gastrointestinal distress. The complexation of different groups of active substances with β-cyclodextrin (β-CD) has drawn considerable interest over recent years. The purpose of this study was to analyze the ketoprofen/β-cyclodextrin (K/β-CD) conjugate complex as well as to assess its anti-inflammatory effect after oral administration (doses of 30 mg/m(2) and 15 mg/m(2) of body surface), compared with ketoprofen. The studies were done on two models of experimentally-induced acute inflammation in rats (n = 48, 6/group), by means of intraplantar administration of a 10% aqueous kaolin suspension and intraperitoneal administration of a 1% sodium thioglycolate solution. The dynamics of the acute inflammatory process and the anti-inflammatory effects were monitored using plethysmometric determinations after 3, 6, 9, 12, 24 and 48 h (plantar inflammation), and the absorbance of the exudates (spectrophotometrically read) and nucleated cell counts after 24 h (peritoneal inflammation). The coupling of ketoprofen with β-CD resulted in increased solubility (100% in 60 min) of the newly-formed product, which further resulted in a higher bioavailability compared with ketoprofen (<40% in 120 min). In both models of experimentally-induced inflammation, the K/β-CD complex had a higher anti-inflammatory activity than ketoprofen.

A colony of guinea pigs (n = 9) with α-mannosidosis was fed a pelleted commercial laboratory guinea pig diet. Over 2 mo, all 9 guinea pigs unexpectedly showed anorexia and weight loss (11.7% to 30.0% of baseline weight), and 3 animals demonstrated transient polyuria and polydipsia. Blood chemistry panels in these 3 guinea pigs revealed high-normal total calcium, high-normal phosphate, and high ALP. Urine specific gravity was dilute (1.003, 1.009, 1.013) in the 3 animals tested. Postmortem examination of 7 animals that were euthanized after failing to respond to supportive care revealed renal interstitial fibrosis with tubular mineralization, soft tissue mineralization in multiple organs, hepatic lipidosis, and pneumonia. Analysis of the pelleted diet revealed that it had been formulated with a vitamin D3 content of more than 150 times the normal concentration. Ionized calcium and 25-hydroxyvitamin D values were both high in serum saved from 2 euthanized animals, confirming the diagnosis of hypervitaminosis D. This report discusses the clinical signs, blood chemistry results, and gross and histologic findings of hypervitaminosis D in a colony of guinea pigs. When unexpected signs occur colony-wide, dietary differentials should be investigated at an early time point.

Perioperative treatment of several rats in our facility with ketoprofen (5 mg/kg SC) resulted in blood loss, peritonitis, and death within a day to a little more than a week after surgery that was not related to the gastrointestinal tract. Published reports have established the 5-mg/kg dose as safe and effective for rats. Because ketoprofen is a nonselective nonsteroidal antiinflammatory drug that can damage the gastrointestinal tract, the putative diagnosis for these morbidities and mortalities was gastrointestinal toxicity caused by ketoprofen (5 mg/kg). We conducted a prospective study evaluating the effect of this therapeutic dose of ketoprofen on the rat gastrointestinal tract within 24 h. Ketoprofen (5 mg/kg SC) was administered to one group of rats that then received gas anesthesia for 30 min and to another group without subsequent anesthesia. A third group was injected with saline followed by 30 min of gas anesthesia. Our primary hypothesis was that noteworthy gastrointestinal bleeding and lesions would occur in both groups treated with ketoprofen but not in rats that received saline and anesthesia. Our results showed marked gastrointestinal bleeding, erosions, and small intestinal ulcers in the ketoprofen-treated rats and minimal damages in the saline-treated group. The combination of ketoprofen and anesthesia resulted in worse clinical signs than did ketoprofen alone. We conclude that a single 5-mg/kg dose of ketoprofen causes acute mucosal damage to the rat small intestine.

The 2011 edition of the Guide for the Care and Use of Laboratory Animals includes new recommendations for the amount of floor space that should be provided to breeding mice. When pairs or trios of continuously breeding mice are housed in shoebox cages, they may have less than this recommended amount of floor space. High housing densities may adversely affect animal health, for example, by compromising air quality inside the cage. Hence, some institutions are carefully reevaluating the microenvironments of breeding cages. The use of individually ventilated cages (IVCs) to house research mice allows for greater control over the quality of the cage microenvironment. The authors evaluated the microenvironments of shoebox cages in an IVC rack system housing breeding and non-breeding Swiss Webster mice. Ammonia concentrations were significantly higher in cages housing breeding trios with two litters. Histopathologic lesions attributable to inhaled irritants such as ammonia were found in mice housed in breeding pairs and trios. The authors conclude that the microenvironments of cages in an IVC rack system housing breeding pairs and trios may be detrimental to animal health.

Cholangiocarcinoma (CCA) is a crucial health problem in northeastern part of Thailand, which is caused by a combination of Opisthorchis viverrini infection and nitrosamine. A better understanding of its molecular mechanism is an important step to discover and develop the new diagnostics and therapies for CCA. To reveal the involvement of potential genes in the development of CCA, the present study investigated the expression kinetics of platelet-derived growth factor alpha (Pdgfa) and its receptor (Pdgfra) during the tumorigenesis of CCA induced by O. viverrini infection with quantitative RT-PCR, and confirmed the expression with immunohistological staining. The results showed that in the hamster model of opisthorchiasis-associated CCA, the expression of Pdgfa was increased after infection plus N-nitrosodimethylamine (NDMA) administration, reached its peak at 2 months post infection, and remained at the high level until 6 months. Similarly, the expression of Pdgfra was increased time-dependently. The positive immunostaining for PDGFA proteins was observed in the cytoplasm of epithelial tumor cells of hamster CCA. Moreover, the analysis of the expression of these genes in 10 cases of human opisthorchiasis-associated CCA showed that Pdgfa was overexpressed in 80%, and Pdgfra was overexpressed in 40% cases (>3.0 folds, compared with the expressions of adjacent normal tissues). This result suggests that PDGFA is likely involved in the tumorigenesis of opisthorchiasis-associated CCA, and may be a promising candidate biomarker for diagnosis and treatment strategies of CCA., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Trimethoprim-sulfamethoxazole (TMP-SMX) medication in the feed or water is commonly administered to immunocompro mised mice to prevent the occurrence of Pneumocystis murina (formerly P. carinii) pneumonia. Therapeutic doses of SMX can cause decreased total and free thyroxine (T4) levels in dogs and thyroid hypertrophy and hyperplasia in mice, rats, and dogs. Our primary objective was to determine whether SMX at doses present in commercially available rodent TMP-SMX feed would pro duce hypothyroidism in mice. Plasma T4 levels were determined prior to and after placement of Brand A TMP-SMX feed (daily SMX dose, 240 mg/kg), Brand B TMP-SMX feed (daily SMX dose, 2400 mg/kg), and their respective controls (doses calculated for a 25-g mouse according to vendor's information). T4 levels in the mice fed Brand B TMP-SMX feed were significantly decreased by 2 wk after feed placement. Levels of thyroid stimulating hormone in male and female mice given Brand B TMP-SMX feed were significantly elevated compared with those of control groups at 6 wk after feed placement, when only these mice showed evidence of thyroid hypertrophy and hyperplasia. No significant change in T4 levels occurred over the course of 11 wk in mice given the Brand A TMP-SMX chow or either control feed. In light of the significant clinical hypothyroidism that occurred in our mice while receiving Brand B TMP-SMX diet, we recommend SMX levels more similar to that of Brand A to avoid such unwanted effects which could confound research data.

Benzene and ethylene oxide are multisite carcinogens in rodents and classified as human carcinogens by the National Toxicology Program. In 2-year mouse studies, both chemicals induced mammary carcinomas. We examined spontaneous, benzene-, and ethylene oxide-induced mouse mammary carcinomas for p53 protein expression, using immunohistochemistry, and p53 (exons 5-8) and H-ras (codon 61) mutations using cycle sequencing techniques. p53 protein expression was detected in 42% (8/19) of spontaneous, 43% (6/14) of benzene-, and 67% (8/12) of ethylene oxide-induced carcinomas. However, semiquantitative evaluation of p53 protein expression revealed that benzene- and ethylene oxide-induced carcinomas exhibited expression levels five- to six-fold higher than spontaneous carcinomas. p53 mutations were found in 58% (7/12) of spontaneous, 57% (8/14) of benzene-, and 67% (8/12) of ethylene oxide-induced carcinomas. H-ras mutations were identified in 26% (5/19) of spontaneous, 50% (7/14) of benzene-, and 33% (4/12) of ethylene oxide-induced carcinomas. When H-ras mutations were present, concurrent p53 mutations were identified in 40% (2/5) of spontaneous, 71% (5/7) of benzene-, and 75% (3/4) of ethylene oxide-induced carcinomas. Our results demonstrate that p53 and H-ras mutations are relatively common in control and chemically induced mouse mammary carcinomas although both chemicals can alter the mutational spectra and more commonly induce concurrent mutations.

Landfarming is a widely used method of treating petrochemical waste through microbial bio-degradation. The effects of residual petrochemical contamination on wildlife, especially terrestrial mammals, are poorly understood. The effects of contaminants on the immune system and hematology of cotton rats (Sigmodon hispidus) living on five abandoned petrochemical landfarms (units 1-5) in Oklahoma were studied. Cotton rats were sampled seasonally (summer and winter) from each landfarm and from five ecologically matched reference sites for 2 yr (1998-2000) and returned to the laboratory for immunological and hematological assays. Overall analysis indicated that rats inhabiting landfarms exhibited decreased relative spleen size compared to rats collected from reference sites, with the landfarm at unit 1 showing the greatest reduction. Cotton rats collected from landfarms also had increased hemoglobin, hematocrit, and platelet levels and decreased blood leukocytes during summer. During winter, an increase in the number of popliteal node white blood cells was observed from rats collected on landfarms. No marked difference was detected for lymphocyte proliferation in response to concanavalin A, pokeweed, or interleukin-2. Lymphokine-activated killer cell lytic ability showed a seasonal pattern, but no treatment differences. No differences between landfarm and reference sites were detected in the hypersensitivity reaction of rats given an intradermal injection of phytohemagluttinin (PHA-P). Comparisons within individual sites indicated that two sites (units 1 and 3) had the greatest effects on immune function and hematology of cotton rats. The results of this study suggest that residual petrochemical waste affects the immune system and hematology of cotton rats living on abandoned landfarms during summer and is complicated by variation in the contaminants found on individual petroleum sites.

Over the last 8 years, a 5-fold increase in the incidence of mice with spontaneous hepatoblastomas and a moderate increase in the incidence of chemically induced hepatoblastomas in B6C3F1 mice occurred in 2-year NTP studies compared to the previous 7 years. There was a positive association between an increased incidence of mice with hepatoblastoma and an increased incidence of mice with hepatocellular tumors in the treated mice. The rate of pulmonary metastases for hepatoblastoma was similar to that of pulmonary metastasis for hepatocellular carcinomas. Although a variety of chemicals caused an increased incidence of mice with hepatoblastoma, there was no apparent association between a specific chemical structure or a biological class of compounds and their capacity to induce hepatoblastomas. Hepatoblastomas frequently arose within hepatocellular carcinomas or adenomas and were induced by the same compounds that induced hepatocellular neoplasms. Therefore, it seems reasonable to combine the incidence of mice with hepatoblastomas and the incidence of mice with hepatocellular carcinomas in hazard identification studies.

In toxicologic testing or experimental studies using animals, an adequate knowledge of spontaneously occurring lesions is required. 144 male and 184 female untreated Syrian golden hamsters (strain Han:AURA) were kept for life under standard laboratory conditions and an investigation of non-neoplastic lesions in relationship to the lifespan was performed. The average lifespan of the males was 106 weeks and that of the female hamsters 97 weeks. While cartilage degeneration of the sternum and fatty degeneration of the femoral bone marrow occurred already in the first half of life with high incidence, the majority of lesions were observed in the second half. The most frequent non-neoplastic changes in various organs were fatty change, calcification, cystic change, hyperplasia and amyloidosis. Such spontaneous lesions were discussed in connection with the same alterations which can also be induced by chemical or hormonal agents.

To identify which region of staphylococcal enterotoxin A (SEA) is responsible for the emetic activity, twelve synthetic peptides corresponding to the entire SEA amino acid sequence and their respective anti-peptide antibodies were prepared and tested. The anti-peptide antibodies were tested for neutralization of SEA-induced emesis in Suncus murinus (Shrew mouse). The results indicate that SEA-induced emesis was neutralized by the mixture of three anti-peptide antibodies to A-7 (corresponding to amino acid residues 121-140), A-8 (141-160) and A-9 (160-180). These findings suggest that the regions corresponding to residues 121-180 may be the epitopes responsible for the emetic activity of SEA.

Extracellular matrix components (ECMs) in histological sections of the kidney cortex from the rats with adriamycin (ADR)-induced nephropathy (5 mg/kg, i.v.) were quantified by an immunohistochemical micromethod. Changes in kidney histopathology and urine and blood biochemistry were investigated. Enlarged kidneys were granular on the surface and pale in color in ADR-treated rats, and these rats had kidneys with glomeruli with expanded mesangial area and with capillary aneurysm. Severe albuminuria, hypoalbuminemia, hypercholesterolemia and disorders in other nephrotic parameters were observed in ADR-treated rats. Type I and IV collagens, fibronectin and laminin contents in the renal cortex of ADR-treated rats at 10 weeks were 329, 317, 263 and 295%, respectively, higher than in each vehicle control, and those at 28 weeks were 1,211, 930, 1,057 and 1,012%, respectively. The glomerular sclerotic abnormalities progressed in a time-dependent manner. Moreover, there was a strong correlation between the ECM levels and serum creatinine and blood urea nitrogen levels. In conclusion, microquantification provided useful information for accurate diagnosis and prognosis of nephrotic lesions and is a good tool to assess the advancement of renal disorders in patients with nephropathy.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic halogenated aromatic hydrocarbon, is a teratogen to induce cleft palate when exposed during the pregnancy. There are inter-strain differences in the sensitivity to cleft palate induced by TCDD and other chemicals including polychlorinated terphenyls (PCTs). The C57BL/6 mouse and the ddY mouse had been shown to be different in the induction of cleft palate following the treatment of PCTs, which attempts us to evaluate the TCDD-induced cleft palate in two mouse strains to understand the mechanism through which TCDD and PCTs induce cleft palate. This study evaluated the induction of cleft palate in the fetuses of ddY and C57BL/6 mice after subcutaneous treatment of TCDD on gestation day (GD) 10.5-14.5 or oral treatment on GD 8.5-13.5. Our results clearly showed that ddY mice, a susceptible strain to PCTs-induced cleft palate, are resistant to the induction of cleft palate by TCDD comparably to the high susceptibility of C57BL/6 mice, suggesting a different teratological mechanism between TCDD and PCTs. In addition, at the low doses, our study supported the concept of "window effect" of TCDD on around GD 12 for the induction of cleft palate in C57BL/6 and ddY mice.

Land-treatment of petroleum wastes is a widely used industrial practice, yet there has been no comprehensive evaluation of the long-term risks to human or terrestrial ecosystems from such practices. We evaluated cotton rat (Sigmodon hispidus) populations on three sites in Oklahoma (USA) that historically used land-treatment for disposal of various petroleum wastes (July 1995-March 1997). Average concentrations of fluoride in soil from these sites ranged from 878 to 4317 mg/kg. A census of resident cotton rats on land-treatment sites revealed a high incidence (40% overall) of dental lesions compared to reference populations (<1% dental lesions). During winter there was a 34% to 65% increase compared to summer in frequency of dental lesions in cotton rats on two of the three land-treatment sites. Incidence of dental lesions on two land-treatment sites was greater (9-16%) in female cotton rats compared to males. Cotton rats from land-treatment sites had higher concentrations of fluoride in bone and greater severity of dental lesions compared to reference animals. Dental lesions were considered to be most consistent with dental fluorosis because of elevated fluoride in bone. Neither concentration of fluoride in soil nor level of fluoride in bone was a good predictor of severity of dental lesions in cotton rats on land-treatment sites.

This study was carried out to determine an effective regimen for pain management in streptococcal cell wall (SCW)-induced arthritis in female Lew/SSN rats. Forty weanling rats lin 2 groups) were trained to accept disks of jelly as part of their dietary regimen. At 8 weeks of age weighing 150 g, SCW arthritis was induced and sublingual buprenorphine tablets were incorporated into the jelly disks to alleviate the pain of acute arthritis, which developed 24 h post-induction. Group A rats received buprenorphine at a rate of 1 mg/kg 12 hourly. Group B rats received buprenorphine at a rate of 2 mg/kg 12 hourly. Both groups of rats were monitored for symptoms of distress using an adaptation of the Morton and Griffin scale of adverse reactions. Group A rats with severe arthritis required additional subcutaneous (s.c.) injections of buprenorphine to alleviate the adverse effects of arthritis. Group B rats, with twice the dose of buprenorphine did not require additional s.c. injections of buprenorphine. Histological sections of rat hocks indicated that the inflammation was suppressed in Group B rats. We concluded that oral administration of buprenorphine is an effective method of pain management in the pathogenesis of SCW-induced arthritis in Lew/SSN rats. In this model of arthritis, oral buprenorphine has a significant anti-inflammatory effect and appears to modulate the destructive arthritic phase in joints in this animal model of arthritis.

As a routine postoperative treatment, a single dose of buprenorphine was given to rats at a dose of 0.05 mg/kg subcutaneously. However, some rats developed abnormal secretions around the nose and mouth and some animals died 3-5 days after surgery and analgesic treatment. At autopsy a yellow fibrous mass was found in the stomach and intestines. Observations of animals given buprenorphine revealed an abnormal ingestion of bedding material. This caused a disturbance to normal digestion, with gastric distension, weight loss or decreased growth rate, constipation and occasionally death. In this study rats were monitored for 6 days following surgery and analgesic treatment. A comparison of growth rates was made between rats given saline and buprenorphine or nalbuphine and between animals kept on bedding or grid floors for the first 24h after treatment. Of the animals held on bedding, the buprenorphine-treated animals did not lose weight as the other animals did, but had on the other hand a decreased growth rate during the measuring period of 6 days after surgery. When denied access to bedding for the first 24 h after surgery, rats given saline or nalbuphine had a reduced weight gain over the first 24 h, similar to the groups held on bedding. Rats held on grid floors and given buprenorphine continued to gain weight for the first 24 h. From day 3, there was no significant difference between the groups, which all gained weight.

Housing conditions influence anatomy, physiology, and behaviour of animals. The aim of this study is to investigate whether the generation of fever, a defence response of the body, is also affected by housing conditions. Golden hamsters (Mesocricetus auratus) were housed in small cages, large cages, or large and enriched cages. After 9 weeks of exposure to their respective environments, the fever response to the administration of lipopolysaccharide (50 micrograms/kg from Salmonella typhosa) was tested. One hundred and twenty experiments in 30 hamsters demonstrated that housing in small cages diminished the fever responses (increase in core temperature and fever index) significantly by approximately 20%, and is likely to be due to a higher stress level. The findings demonstrate that the results of physiological experiments are not only influenced by the experimental design, but also by pre-experimental housing conditions.

This study was designed to seek the appropriate scanning parameters for T1 and T2 weighted images of rat head by use of a high (4.7 T) magnetic field strength magnetic resonance imaging unit. The optimum values of variables for T1 weighted images were considered to be a time of repetition of 1,000 msec, and for T2 weighted images, 8 echoes. When the sagittal images of a healthy rat head were scanned using these optimum values, the cerebrum, cerebellum, olfactory bulb, pituitary gland, pineal gland, spinal cord, tongue, nasopharynx, nasal conchae, vermis and cerebrospinal fluid were clearly observed in either T1 or T2 weighted images. Moreover, a primary brain tumor induced by ethylnitrosourea was depicted as a high signal intensity mass in T2 and contrast-enhanced T1 weighted images.

Naked mole-rats have no access to obvious sources of vitamin D and therefore have an impoverished vitamin D status. In an investigation into the effects of vitamin D supplementation, inadvertently supraphysiological doses of 130,000 times the normal dose of vitamin D were administered. Within 5 days animals appeared lethargic, with reduced food intake. All but one of the seven animals were killed and blood was collected. Plasma vitamin D metabolites 25(OH)D and 1,25(OH)2D and calcium were determined. Both vitamin D metabolite concentrations exceeded the upper limits of sensitivity of the assays (> 100 ng/ml 25(OH)D and > 210 pg/ml 1,25(OH)2D). Active calcium uptake in the intestine was evident along with concomitant increases in calcium concentration in plasma, bone, and teeth. The remaining animal survived, but showed scab-like formations in the skin around the lower jaw and along the nipple line. X-ray analyses revealed calcium deposition in these cornified regions, although there was no evidence of metastatic calcification in other tissues. Deposition of excess calcium in skin that is regularly sloughed off and in teeth that are continuously worn down and replaced may reduce the vitamin D-induced hypercalcaemia and thus alleviate the effects of vitamin D intoxication.

The effect of lead exposure on cellular immunity, hematology, and reproductive and body condition in mature cotton rats (Sigmodon hispidus) was examined. Two groups of 36 cotton rats each were exposed to 0, 100, or 1,000 ppm lead in drinking water for either 7 or 13 weeks, between 31 August and 2 December 1990. Specific and non-specific cell-mediated immunity was assessed by measuring splenocyte proliferative responses to polyclonal mitogens (Concanavalin A and Pokeweed mitogen), in vivo 24-hr delayed-type hypersensitivity, metabolic activity of peritoneal macrophages, spleen mass and cellularity, and immune organ development. General physiological condition was assessed from hematological, morphological, and reproductive measures. Immune function was sensitive to lead exposure based on depressed proliferative responses of cultured splenocytes, smaller popliteal lymph nodes, and larger spleens among cotton rats receiving 1,000 ppm lead. Spleen mass was reduced in cotton rats receiving 100 ppm lead. Total leukocytes, lymphocytes, neutrophils, eosinophils, total splenocyte yield, packed cell volume, hemoglobin, and mean corpuscular hemoglobin were sensitive to lead exposure. Effects of lead exposure on general condition and reproductive parameters included reduced mass of liver, seminal vesicles, and epididymes in males following a 7-week exposure. Histopathologic changes reflected lead toxicity and included altered renal proximal tubular epithelium, renal intranuclear inclusions, and in some cases, lowered numbers of sperm and developing follicles. In general, lesions were more pronounced with increased lead concentration and longer exposure.

We have developed an in situ mammalian model for evaluating environmental contamination using wild cotton rats. In a series of experiments, 200 male cotton rats were captured during 4 collection periods (spring 1991 = 35; fall 1991 = 60; spring 1992 = 53; fall 1992 = 52). A total of 103 of these cotton rats were captured from control sites, and the remaining 97 were captured from an abandoned oil refinery. All sites were located in the vicinity of Cyril, Oklahoma. There were alterations in the incisors of cotton rats captured from the refinery site. Normal color of cotton rat incisors is deep yellow-orange, which is imparted by a pigment normally produced by ameloblasts. Grossly, the upper incisors of 37 of 97 rats and lower incisors of 54 of 97 rats were affected. The affected incisors were white, chalky, and thin with striations and erosions of the enamel. Microscopic examination revealed that there were dysplastic and necrotic changes in the ameloblasts. The bone fluoride levels were significantly higher in rats captured from the refinery as compared to the rats captured from the control sites.

A recently developed method was used to identify the structural moieties that are not represented among the chemicals tested in the U.S. National Toxicology Program rodent cancer bioassay. Inclusion of those chemicals in the bioassay would increase the informational content of rodent cancer assay data base.

Calcification of the urinary bladder epithelium was observed in 19 of 30 and 18 of 30 wild cotton rats from control and petrochemical-contaminated sites, respectively. The rats in the two sites did not differ significantly in respect of serum calcium and phosphorus concentrations. The calcification was considered to be dystrophic in nature. An unidentified factor common to both control and petrochemical-contaminated sites was considered to be responsible for this syndrome.

Acute tannic acid intoxication was studied in mice and sheep. In mice, following oral administration of 2.0 to 4.6 g of tannic acid kg-1 bodyweight, periacinar coagulative and haemorrhagic necrosis occurred in the liver. In sheep, following oral (8 g kg-1 bodyweight) administration of tannic acid, liver necrosis was not observed either histologically or detected biochemically, although transmission electron microscopy showed focal hepatocellular necrosis, steatosis and acicular crystal cleft formation. In sheep given tannic acid intraperitoneally (0.1 g kg-1 bodyweight), liver necrosis occurred and plasma sodium and glucose levels significantly (P < 0.05) decreased while packed cell volume and plasma aspartate aminotransferase, alkaline phosphatase, creatinine and bilirubin significantly (P < 0.01) rose. The results for blood-gas and acid-base determinations, blood haemoglobin and oxygenation showed significant increases in arterial blood methaemoglobin concentration (P < 0.05) and decreases in blood pH (P < 0.01) and oxyhaemoglobin concentration (P < 0.05) in sheep by 32 hours after oral dosing with 8 g of tannic acid kg-1 bodyweight. In sheep given tannic acid intraperitoneally, methaemoglobinaemia was not detected, but metabolic acidosis with a compensatory respiratory alkalosis occurred. Thus, it would appear that although tannic acid is hepatotoxic when given orally to mice or intraperitoneally to sheep, it does not produce renal or significant hepatic injury in sheep when given orally, but rather causes metabolic acidosis and methaemoglobinaemia.

The availability of safe parenteral anesthetics for use in Syrian hamsters is limited. We evaluated the effects of Telazol-xylazine (TZX) combinations with respect to anesthetic efficacy and potential for tissue damage. Two dose levels of the combination were administered by both the intraperitoneal (IP) and intramuscular (IM) routes. TZX by the IM route failed to consistently produce anesthesia and caused gross and histopathologic muscle lesions. IP administration of 20 mg/kg Telazol combined with 10 mg/kg xylazine was adequate for restraint purposes. IP administration of 30 mg/kg Telazol combined with 10 mg/kg xylazine produced a safe, reliable level of surgical anesthesia without evidence of gross or histopathologic lesions. There was no nephrotoxicity at either concentration of the anesthetic. A dose level of TZX that provides safe parenteral anesthesia in Syrian hamsters was determined.

The effects of administration of a commercially available extract of Gingko biloba (EGB) on bromethalin-induced brain lipid peroxidation and cerebral edema in adult male Sprague-Dawley rats was determined. Gingko biloba extract was given (100 mg/kg) by gavage immediately after bromethalin (1.0 mg/kg) administration. Rats were euthanatized at 24 hours after dosing. Brain lipid peroxidation was determined by measurement of brain malonaldehyde-thiobarbituric acid chromophore (MDA-TBA) concentration, brain sodium concentration, and brain water content. Treatment of bromethalin-dosed rats (10/group) with EGB was associated with a statistically significant (P less than 0.05) decrease in clinical sign severity, compared with bromethalin-dosed saline solution-treated rats. All rats given bromethalin and saline solution developed clinical signs of toxicosis including CNS depression, hind limb weakness, ataxia, paralysis, and coma. Some rats given bromethalin and EGB developed clinical signs, however, none developed hind limb paralysis. The brain MDA-TBA concentration (2.4 +/- 0.5 delta MDA-TBA concentration/mg of protein), percentage of water in brain tissue (80.3 +/- 0.30%), and brain sodium concentration (6.68 +/- 0.21 mg/g of dry weight) were significantly increased in rats given bromethalin and saline solution, compared with control rats given saline solution (1.0 +/- 0.1 delta MDA-TBA concentration/mg of protein; 78.1 +/- 0.33% water in brain tissue; 4.83 +/- 0.30 mg of brain Na+/g of dry weight) and rats given bromethalin and EGB (1.6 +/- 0.2 delta MDA-TBA concentration/mg of protein; 79.3 +/- 0.31% water in brain tissue; 5.37 +/- 0.34 mg of brain Na+/g of dry weight).(ABSTRACT TRUNCATED AT 250 WORDS)

Micrencephalic neonatal pups were obtained from pregnant Crj:CD (SD) rats once treated with 5 mg/kg of N-methyl-N-nitrosourea (MNU) or 40 mg/kg of methylazoxymethanol (MAM) on day 12, 13, 14 or 15 of gestation (vaginal plug = day 0). They were reared by their own mothers and were subjected to various neurobehavioral tests during the suckling period, days 0 to 22 after birth. The brain weights in the MNU- and MAM-treated pups on postnatal day 22 were significantly less than those in the control pups. These micrencephalic pups were retarded in neurobehavioral ontogeny. By several tests, each of them showed an impaired performance such as paired limb movement, clumsy locomotion or hyperreflexive reaction. These behavioral disorders appeared different according to the day of treatment, without any substantial difference between the test compounds, MNU and MAM. The findings suggest that the different neurobehavioral characteristics in the micrencephalic pups may reflect their different brain disorders induced by the test compounds given on the different period of the treatment.

Feeding of high levels of uracil to laboratory rodents results in the formation of calculi in the lumen of the urinary bladder. This urolithiasis stimulates cellular proliferation in the bladder and has been used in studies of two-stage carcinogenesis. Quantitation of uracil in rodent diet was achieved by extraction from the diet with ammonium hydroxide. The extract was applied to a strong anion-exchange solid-phase extraction column. Uracil is not retained on this matrix which adsorbs the majority of contaminants in the extract. The uracil was quantitated by HPLC on an ODS microbore column (100 x 2 mm internal diameter) eluted at 0.5 ml/min with 200 mM KH2PO4, pH 3.5, at 30 degrees C. Three structurally related pyrimidine bases, cytosine, uracil, and thymine, showed increasing retention on this column/solvent combination, thereby demonstrating selectivity of the analysis. Recovery of uracil was 76-90% with lower values observed when dietary levels of uracil were in excess of 4.5%.

In a survey of fungi and mycotoxin conterminating acha (Digitaria exilis Stapf) in Plateau State of Nigeria, 96 fungal isolates were made. Screening of the fungi isolates for their mycotoxin-producing potentials showed that Aspergillus quadrilineatus (Thom and Raper) produced some of the most toxic mycotoxins. Two extracts of the Aspergillus quadrilineatus (the petroleum ether soluble extracts [PER] and the petroleum ether defatted crude extract [PEDCR]) were tested for acute toxicity in mice, chicks and cattle. The ip LD50 of PER in mice was 1148 mg/kg, and the oral LD50 of PEDCR was 566 mg/kg in mice and 556 mg/kg in chicks. The ip LD50 of PEDCR in mice was 21 mg/kg. The toxic signs of PER and PEDCR in mice and chicks included tachypnea, tachycardia, anorexia, somnolence, diarrhea, coma and death. The main postmortem findings were congestion of heart, liver, kidney and lungs and sloughing of the wall of stomach and hemorrhagic enteritis. The histopathologic findings in dead animals included edema and mild degeneration of the myocardium and necrosis of kidney tubular epithelial cells, hepatocytes and bronchioles. The only clinical observation in 1 calf orally dosed with a culture of Aspergillus quadrilineatus of maize was transient whole body tremors which occurred 1 h after dosing, tachycardia and profuse salivation. No significant histopathologic changes were found in the organs of the sacrificed calf.

To evaluate the role of endotoxin during Gram-negative bacterial meningitis, the nervous lesions of piglets, calves, rabbits and mice were compared by direct inoculation of Escherichia coli lipopolysaccharide into the central nervous system. Suppurative leptomeningitis was induced in piglets by small doses of lipopolysaccharide. Mice also had a mild suppurative inflammation in the leptomeninges. In contrast, calves showed suppurative pachymeningitis, but no lesions in the leptomeninges. Leptomeningeal inflammation was not induced in rabbits. Induction of the leptomeningitis by endotoxin was compared with sensitivity to intravenous or intraperitoneal endotoxin in these species.

The histomorphologic features of spontaneous and chemically-induced lung neoplasms in male and female B6C3F1 mice and Fischer 344 rats are described. Primary pulmonary neoplasms in mice and rats were classified as alveolar/bronchiolar (A/B) adenoma or carcinoma (including variants with squamous and mucinous cell differentiation), bronchial adenoma or carcinoma, squamous cell carcinoma or mesenchymal tumors. A/B adenomas and carcinomas were the most common spontaneous pulmonary neoplasms observed in both mice and rats, but were observed less frequently in rats. In the National Toxicology Program (NTP) historical control database the incidence of spontaneous A/B adenomas in male (n = 2,084) and female (n = 2,079) mice is 13.8% and 4.9%, respectively; for A/B carcinomas, it is 5.3% and 2.4%, respectively. In male (n = 3,877) and female (n = 3,919) rats, spontaneous pulmonary neoplasms are rare with historical control rates less than 3% for A/B adenomas or carcinomas in either sex. The spontaneous A/B adenomas and carcinomas observed in mice and rats typically had papillary, solid or mixed (papillary and solid) histologic growth patterns. Pulmonary neoplasms from mice and rats treated with chemical carcinogens reviewed from 2-year studies consisted primarily of A/B adenomas and carcinomas. These tumors had papillary, glandular/tubular, solid or mixed (combination of 2 or more) histologic growth patterns. A few of the A/B neoplasms had areas of squamous or mucinous cell differentiation. Other less frequently occurring spontaneous and chemically-induced neoplasms included squamous cell carcinomas, bronchial adenomas and carcinomas, and sarcomas.