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Obstructive voiding disorder (OVD) occurs during aging in men and is often, but not always, associated with increased prostate size, due to benign prostatic hyperplasia (BPH), prostatitis, or prostate cancer. Estrogens are known to impact the development of both OVD and prostate diseases, either during early urogenital tract development in fetal-neonatal life or later in adulthood. To examine the potential interaction between developmental and adult estrogen exposure on the adult urogenital tract, male CD-1 mice were perinatally exposed to bisphenol A (BPA), diethylstilbestrol (DES) as a positive control, or vehicle negative control, and in adulthood were treated for 4 months with Silastic capsules containing testosterone and estradiol (T+E2) or empty capsules. Animals exposed to BPA or DES during perinatal development were more likely than negative controls to have urine flow/kidney problems and enlarged bladders, as well as enlarged prostates. OVD in adult T+E2-treated perinatal BPA and DES animals was associated with dorsal prostate hyperplasia and prostatitis. The results demonstrate a relationship between elevated exogenous estrogen levels during urogenital system development and elevated estradiol in adulthood and OVD in male mice. These findings support the two-hit hypothesis for the development of OVD and prostate diseases.

Sutherlandia frutescens is a medicinal plant, traditionally used to treat various types of human diseases, including cancer. Previous studies of several botanicals link suppression of prostate cancer growth with inhibition of the Gli/hedgehog (Gli/Hh) signaling pathway. Here we hypothesized the anti-cancer effect of S. frutescens was linked to its inhibition of the Gli/Hh signaling in prostate cancer. We found a dose- and time-dependent growth inhibition in human prostate cancer cells, PC3 and LNCaP, and mouse prostate cancer cell, TRAMP-C2, treated with S. frutescens methanol extract (SLE). We also observed a dose-dependent inhibition of the Gli-reporter activity in Shh Light II and TRAMP-C2QGli cells treated with SLE. In addition, SLE can inhibit Gli/Hh signaling by blocking Gli1 and Ptched1 gene expression in the presence of a Gli/Hh signaling agonist (SAG). A diet supplemented with S. frutescens suppressed the formation of poorly differentiated carcinoma in prostates of TRAMP mice. Finally, we found Sutherlandioside D was the most potent compound in the crude extract that could suppress Gli-reporter in Shh Light II cells. Together, this suggests that the S. frutescens extract may exert anti-cancer effect by targeting Gli/Hh signaling, and Sutherlandioside D is one of the active compounds., (© 2015 International Federation for Cell Biology.)

Oil and natural gas operations have been shown to contaminate surface and ground water with endocrine-disrupting chemicals. In the current study, we fill several gaps in our understanding of the potential environmental impacts related to this process. We measured the endocrine-disrupting activities of 24 chemicals used and/or produced by oil and gas operations for five nuclear receptors using a reporter gene assay in human endometrial cancer cells. We also quantified the concentration of 16 of these chemicals in oil and gas wastewater samples. Finally, we assessed reproductive and developmental outcomes in male C57BL/6J mice after the prenatal exposure to a mixture of these chemicals. We found that 23 commonly used oil and natural gas operation chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors, and mixtures of these chemicals can behave synergistically, additively, or antagonistically in vitro. Prenatal exposure to a mixture of 23 oil and gas operation chemicals at 3, 30, and 300 μg/kg · d caused decreased sperm counts and increased testes, body, heart, and thymus weights and increased serum testosterone in male mice, suggesting multiple organ system impacts. Our results suggest possible adverse developmental and reproductive health outcomes in humans and animals exposed to potential environmentally relevant levels of oil and gas operation chemicals.

A socially-housed New Zealand white rabbit presented with a large subcutaneous mass on the ventral thorax approximately 11 mo after the intrahepatic delivery of a suspension of VX2 carcinoma cells to induce hepatocellular carcinoma as part of a nanoparticle study. The mass and closely associated axillary lymph node were removed en bloc. Immunohistochemical staining identified the mass as an undifferentiated carcinoma. The rabbit demonstrated no appreciable pathology at the study end point at 16 mo after VX2 inoculation. An additional rabbit from the same VX2 injection cohort was found at necropsy to have an unanticipated intraabdominal mass, also identified as an undifferentiated carcinoma. This case report summarizes the molecular analysis of both tumors through a novel PCR assay, which identified the delayed and aberrant onset of VX2 carcinoma in an extended timeframe not previously reported.

Exposure to bisphenol A (BPA) is implicated in many aspects of metabolic disease in humans and experimental animals. We fed pregnant CD-1 mice BPA at doses ranging from 5 to 50,000μg/kg/day, spanning 10-fold below the reference dose to 10-fold above the currently predicted no adverse effect level (NOAEL). At BPA doses below the NOAEL that resulted in average unconjugated BPA between 2 and 200pg/ml in fetal serum (AUC0-24h), we observed significant effects in adult male offspring: an age-related change in food intake, an increase in body weight and liver weight, abdominal adipocyte mass, number and volume, and in serum leptin and insulin, but a decrease in serum adiponectin and in glucose tolerance. For most of these outcomes non-monotonic dose-response relationships were observed; the highest BPA dose did not produce a significant effect for any outcome. A 0.1-μg/kg/day dose of DES resulted in some but not all low-dose BPA outcomes., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Galectin-3 (gal-3) is involved in the metastatic cascade and interacts with the cancer-associated carbohydrate, Thomsen-Freidenreich (TF) antigen during early stages of metastatic adhesion and tumor formation. Our laboratory previously utilized bacteriophage display to select a peptide, G3-C12, with high specificity and affinity for gal-3 that was able to inhibit cancer cell adhesion. We hypothesized that G3-C12 would inhibit TF/gal-3 and gal-3/gal-3 interactions in vitro and in vivo and would moderate early steps of the metastatic cascade leading to reduced carcinogenesis in vivo. To test this, adhesion of multiple breast carcinoma cell lines to purified gal-3 and a TF-mimic was measured in the presence/absence of G3-C12 resulting in an average reduction of cellular adhesion by 50 and 59 %, respectively. Sensitive optical imaging experiments were utilized to monitor the fate of intravenously injected MDA-MB-231 human breast carcinoma cells expressing luciferase into athymic nude mice in the presence/absence of G3-C12 in vivo. Intravenous administration of G3-C12 reduced lung colonization of MDA-MB-231-luciferase cells within mice by 72 % when compared to saline, whereas, control peptide treatments resulted in no significant reduction of colonization. Histologic examination of excised lung tissue, at day 70, revealed that mice treated with G3-C12 possessed 4.63 ± 3.07 tumors compared to 14.13 ± 3.56 tumors within mice treated with saline. Also, within both saline and control peptide treatment groups, 37 % of mouse lungs contained tumor thrombi, compared to 0 % within the G3-C12 treatment group. This study demonstrated that G3-C12 significantly reduced metastatic cell deposition and consequent outgrowth within vasculature of mice.

The tumor suppressor TP53 plays a crucial role in cancer biology, and the TP53 gene is the most mutated gene in human cancer. Trp53 knockout mouse models have been widely used in cancer etiology studies and in search for a cure of cancer with some limitations that other model organisms might help overcome. Via pronuclear microinjection of zinc finger nucleases (ZFNs), we created a Tp53 knockout rat that contains an 11-bp deletion in exon 3, resulting in a frameshift and premature terminations in the open reading frame. In cohorts of 25 homozygous (Tp53(Δ11/Δ11)), 37 heterozygous (Tp53(Δ11/+)) and 30 wild-type rats, the Tp53(Δ11/Δ11) rats lived an average of 126 days before death or removal from study because of clinical signs of abnormality or formation of tumors. Half of Tp53(Δ11/+) were removed from study by 1 year of age because of tumor formation. Both Tp53(Δ11/+) and Tp53(Δ11/Δ11) rats developed a wide spectrum of tumors, most commonly sarcomas. Interestingly, there was a strikingly high incidence of brain lesions, especially in Tp53(Δ11/Δ11) animals. We believe that this mutant rat line will be useful in studying cancer types rarely observed in mice and in carcinogenicity assays for drug development.

Medroxyprogesterone acetate (MPA) is a synthetic progestin commonly administered to postmenopausal women for hormone replacement therapy and has been associated with increased risk of breast cancer. MPA has been shown to accelerate the development of mammary tumors in a 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer animal model. Previously, we have shown that intraperitoneally administered apigenin effectively treated and prevented the progression of MPA-accelerated breast cancer in DMBA-induced and xenograft mammary cancer models. Here we used the DMBA model to examine the chemopreventive effect of dietary apigenin against MPA-accelerated tumors with 3 different levels of apigenin (0.02%, 0.1%, and 0.5% w/w) incorporated into a phytoestrogen-free diet. Results showed that 0.1% dietary apigenin reduced MPA-dependent tumor incidence; however, the same dietary level increased tumor multiplicity in animals that developed tumors. Neither 0.02% nor 0.5% dietary apigenin reduced MPA-dependent tumor incidence or latency, and tumor multiplicity increased significantly in response to 0.5% apigenin. These results contrast with previous chemopreventive effects observed when apigenin was administered intraperitoneally, suggesting that route of administration may influence its action. Consequently, until further research clarifies the effect of dietary apigenin on progestin-accelerated mammary tumors, caution should be exercised when considering the flavonoid as a dietary supplement for preventing hormone-dependent breast cancer.

Previous evidence suggests soy genistein may be protective against prostate cancer, but whether this protection involves an estrogen receptor (ER)-dependent mechanism is unknown. To test the hypothesis that phytoestrogens may act through ERα or ERβ to play a protective role against prostate cancer, we bred transgenic mice lacking functional ERα or ERβ with transgenic adenocarcinoma of mouse prostate (TRAMP) mice. Dietary genistein reduced the incidence of cancer in ER wild-type (WT)/transgenic adenocarcinoma of mouse prostate mice but not in ERα knockout (KO) or ERβKO mice. Cancer incidence was 70% in ERWT mice fed the control diet compared with 47% in ERWT mice fed low-dose genistein (300 mg/kg) and 32% on the high-dose genistein (750 mg/kg). Surprisingly, genistein only affected the well differentiated carcinoma (WDC) incidence but had no effect on poorly differentiated carcinoma (PDC). No dietary effects have been observed in either of the ERKO animals. We observed a very strong genotypic influence on PDC incidence, a protective effect in ERαKO (only 5% developed PDC), compared with 19% in the ERWT, and an increase in the incidence of PDC in ERβKO mice to 41%. Interestingly, immunohistochemical analysis showed ERα expression changing from nonnuclear in WDC to nuclear in PDC, with little change in ERβ location or expression. In conclusion, genistein is able to inhibit WDC in the presence of both ERs, but the effect of estrogen signaling on PDC is dominant over any dietary treatment, suggesting that improved differential targeting of ERα vs. ERβ would result in prevention of advanced prostate cancer.

Calcium-modulating cyclophilin ligand (Caml) is a ubiquitously expressed cytoplasmic protein that is involved in multiple signaling and developmental pathways. An observation in our laboratory of a protein-protein interaction between Caml and the cytoplasmic region of Cadherin23 led us to speculate that Caml might be important in the inner ear and play a role in the development and/or function of hair cells. To address this question, we generated a mouse line in which Caml expression was eliminated in Atoh1-expressing cells of the inner ear upon administration of tamoxifen. Tamoxifen was administered immediately after birth to neonates to assess the effect of loss of Caml in the inner ear during postnatal development. Hearing in treated animals was tested by auditory brain stem response (ABR) analysis and cochlear pathology was evaluated by light microscopy. Lack of Caml expression in the inner ear leads to severe loss of cochlear hair cells and complete deafness. Elucidating the role of Caml in the inner ear will aid our understanding of the molecular pathways important for auditory development and function.

Members of the fibroblast growth factor (FGF) family have been associated with tumor progression and angiogenesis, though the mechanism through which they affect the progression of breast cancer remains elusive. We recently showed that progestins increase the production of the potent angiogenic factor VEGF in an in vivo BT-474 human breast cancer cell-derived xenograft model. In this study we sought to determine the effect of progesterone (P) on regulation of specific FGF family members (FGF-2, FGF-4 and FGF-8) in the same model. Using immunohistochemistry we found that treatment with P significantly reduced FGF-2 and FGF-8 levels, while modestly increasing the levels of FGF-4 in tumors collected at the termination of the study or soon after P treatment began. The in vivo observations with FGF-2 were confirmed in cultured BT-474 cells, though the P-mediated reduction in FGF-2 was not blocked by the anti-progestin RU-486, suggesting that classical progesterone receptors (PR) are not involved in FGF-2 down-regulation. Also, P did not affect levels of FGF-2 mRNA in BT-474 cells, indicating that P exerts its effects on FGF-2 post-transcriptionally. Our observations suggest that the in vivo stimulation of BT-474 cell growth by P is associated with down-regulation of FGF-2 and FGF-8. Furthermore, since FGF-4 levels increased during P-treatment, FGF-4 may be required for tumor growth and maintenance and might therefore be a potential therapeutic target through which to suppress P-dependent tumor growth.

Col1a2-deficient (oim) mice synthesize homotrimeric type I collagen due to nonfunctional proα2(I) collagen chains. Our previous studies revealed a postnatal, progressive type I collagen glomerulopathy in this mouse model, but the mechanism of the sclerotic collagen accumulation within the renal mesangium remains unclear. The recent demonstration of the resistance of homotrimeric type I collagen to cleavage by matrix metalloproteinases (MMPs), led us to investigate the role of MMP-resistance in the glomerulosclerosis of Col1a2-deficient mice. We measured the pre- and post-translational expression of type I collagen and MMPs in glomeruli from heterozygous and homozygous animals. Both the heterotrimeric and homotrimeric isotypes of type I collagen were equally present in whole kidneys of heterozygous mice by immunohistochemistry and biochemical analysis, but the sclerotic glomerular collagen was at least 95-98% homotrimeric, suggesting homotrimeric type I collagen is the pathogenic isotype of type I collagen in glomerular disease. Although steady-state MMP and Col1a1 mRNA levels increased with the disease progression, we found these changes to be a secondary response to the deficient clearance of MMP-resistant homotrimers. Increased renal MMP expression was not sufficient to prevent homotrimeric type I collagen accumulation., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Idiopathic lung lesions characterized by dense perivascular cuffs of lymphocytes and a lymphohistiocytic interstitial pneumonia have been noted in research rats since the 1990s. Although the etiology of this disease has remained elusive, a putative viral etiology was suspected and the term 'rat respiratory virus' (RRV) has been used in reference to this disease agent. The purpose of this study was to determine whether Pneumocystis carinii infection in immunocompetent rats can cause idiopathic lung lesions previously attributed to RRV. In archived paraffin-embedded lungs (n = 43), a significant association was seen between idiopathic lung lesions and Pneumocystis DNA detected by PCR. In experimental studies, lung lesions of RRV developed in 9 of 10 CD rats 5 wk after intratracheal inoculation with P. carinii. No lung lesions developed in CD rats (n = 10) dosed with a 0.22-μm filtrate of the P. carinii inoculum, thus ruling out viral etiologies, or in sham-inoculated rats (n = 6). Moreover, 13 of 16 CD rats cohoused with immunosuppressed rats inoculated with P. carinii developed characteristic lung lesions from 3 to 7 wk after cohousing, whereas no lesions developed in rats cohoused with immunosuppressed sham-inoculated rats (n = 7). Both experimental infection studies revealed a statistically significant association between lung lesion development and exposure to P. carinii. These data strongly support the conclusion that P. carinii infection in rats causes lung lesions that previously have been attributed to RRV.

Many botanical compounds have been proposed to prevent cancer. We investigated the cancer treatment and prevention abilities of apigenin, baicalein, curcumin, epigallocatechin 3-gallate (EGCG), genistein, quercetin, and resveratrol both in vivo in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice as well as in vitro in prostate cancer cell lines. In our experiments, these seven compounds act similarly to the Hedgehog antagonist cyclopamine, a teratogenic plant alkaloid, which had been previously shown to "cure" prostate cancer in a mouse xenograft model. With IC(50) values ranging from <1 to 25 mumol/L, these compounds can inhibit Gli1 mRNA concentration by up to 95% and downregulate Gli reporter activity by 80%. We show that four compounds, genistein, curcumin, EGCG, and resveratrol, inhibit Hedgehog signaling as monitored by real-time reverse transcription-PCR analysis of Gli1 mRNA concentration or by Gli reporter activity. Three compounds, apigenin, baicalein, and quercetin, decreased Gli1 mRNA concentration but not Gli reporter activity. Our results show that these compounds are also able to reduce or delay prostate cancer in vivo in TRAMP mice. All seven compounds, when fed in combination as pure compounds or as crude plant extracts, inhibit well-differentiated carcinoma of the prostate by 58% and 81%, respectively. In vitro, we show that all seven compounds also inhibit growth in human and mouse prostate cancer cell lines. Mechanistically, we propose the Hedgehog signaling pathway to be a direct or indirect target of these compounds. These botanicals at pharmacologic concentrations are potentially safer and less expensive alternatives to cyclopamine and its pharmaceutical analogues for cancer therapy., ((c) 2010 AACR.)

The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5-7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonance imaging, by 89%. Tumors expressed estrogen receptors (ER), progesterone receptor (PR), and Erbb2. ERalpha and PR were overexpressed in tumor compared to adjacent non-tumor mammary gland. Thus, this model is highly relevant to hormone responsive human breast cancers.

Understanding the principles of biological self-assembly is indispensable for developing efficient strategies to build living tissues and organs. We exploit the self-organizing capacity of cells and tissues to construct functional living structures of prescribed shape. In our technology, multicellular spheroids (bio-ink particles) are placed into biocompatible environment (bio-paper) by the use of a three-dimensional delivery device (bio-printer). Our approach mimics early morphogenesis and is based on the realization that the genetic control of developmental patterning through self-assembly involves physical mechanisms. Three-dimensional tissue structures are formed through the postprinting fusion of the bio-ink particles, in analogy with early structure-forming processes in the embryo that utilize the apparent liquid-like behavior of tissues composed of motile and adhesive cells. We modeled the process of self-assembly by fusion of bio-ink particles, and employed this novel technology to print extended cellular structures of various shapes. Functionality was tested on cardiac constructs built from embryonic cardiac and endothelial cells. The postprinting self-assembly of bio-ink particles resulted in synchronously beating solid tissue blocks, showing signs of early vascularization, with the endothelial cells organized into vessel-like conduits.

Mouse antibody production (MAP) tests have become the standard assay for the detection of murine viral contamination in biologic materials, such as cell lines and transplantable tumors. However, newly developed PCR assays offer the advantage of lower cost, faster turn around times, and eliminate the use of live animals. In this study, the MAP test and a panel of PCR assays were compared for the detection of 11 different viral contaminants of cell lines and transplantable tumors. The PCR assays had either better or comparable results to the MAP test for all agents tested. The results of this study confirm that PCR assays are an effective method for detection of viral contamination and can be used as an alternative to the MAP test.

Vitamin A toxicosis and vitamin E deficiency was diagnosed in a commercial rabbit-breeding colony and was associated with reproductive abnormalities, abortions, and poor survivability of kits in the breeding colony. Paresis and muscular dystrophy were noted in juvenile rabbits. Another group of New Zealand White rabbits from the same commercial colony was used to assess the effect of vitamin E-based therapy on clinical signs, reproduction, and vitamin A and E serum and liver levels. Blood samples were taken before and after dietary changes and vitamin E therapy. Serum vitamin E remained low after feeding a diet containing the recommended levels of vitamin E. Administration of vitamin E for 2 weeks lowered the serum vitamin A levels and increased the vitamin E serum and liver levels. In conclusion, vitamin E therapy appears to be an effective treatment for hypervitaminosis A., (Copyright 2004 American Association for Laboratory Animal Science)

A novel Respirovirus was isolated from nasopharyngeal swab specimens from clinically normal laboratory guinea pigs, and was characterized and named caviid parainfluenza virus 3 (CavPIV-3). The CavPIV-3 is enveloped, is 100 to 300 nm in diameter, and has a characteristic 15-nm-diameter chevron-shaped virus ribonucleocapsid protein. Sequence analysis of the fusion glycoprotein of CavPIV-3 revealed it to be 94% identical to human and guinea pig parainfluenza 3 (PIV-3) viruses and 80% identical to bovine PIV-3. To determine whether CavPIV-3 causes clinical disease in laboratory guinea pigs and to compare the serologic response of guinea pigs to CavPIV-3 and to other paramyxoviruses, an infection study was performed, in which groups of guinea pigs were inoculated with CavPIV-3, Sendai virus, simian virus 5 (SV-5), murine pneumonia virus (PVM), or bovine PIV-3 virus. During the course of the study, guinea pigs were maintained in an infectious disease suite, housed in Micro-Isolator cages, and were only manipulated under a laminar flow hood. Clinical signs of disease were not observed in any of the paramyxovirus-inoculated guinea pigs during the eight-week course of the study, and histologic signs of disease were not evident at necropsy eight weeks after inoculation. Guinea pigs inoculated with CavPIV-3, Sendai virus, PVM, and bovine PIV-3 developed robust homologous or heterologous serologic responses. In contrast, guinea pigs inoculated with SV-5 developed modest or equivocal serologic responses, as assessed by use of an enzyme-linked immunosorbent assay. Further, use of the SV-5 enzyme-linked immunosorbent assay resulted in the highest degree of non-specific reactivity among all of the paramyxovirus assays. In summary, CavPIV-3 is a novel guinea pig Respirovirus that subclinically infects laboratory guinea pigs, resulting in a robust serologic response, but no observed clinical or histologic disease. The CavPIV-3 fusion glycoprotein gene sequence is available from GenBank as accession No. AF394241, and the CavPIV-3 virus is available from the American Type Culture Collection as accession No. DR-1547.

Mice minute virus (MMV) and mouse parvovirus (MPV) type 1 are the two parvoviruses known to naturally infect laboratory mice and are among the most prevalent infectious agents found in contemporary laboratory mouse colonies. Serologic assays are commonly used to diagnose MMV and MPV infections in laboratory mice; however, highly accurate, high-throughput serologic assays for the detection of MMV- and MPV-infected mice are needed. To this end, the major capsid viral protein (VP2) genes of MMV and MPV were cloned and MMV recombinant VP2 (rVP2) and MPV rVP2 proteins were expressed by using a baculovirus system. MMV rVP2 and MPV rVP2 spontaneously formed virus-like particles that were morphologically similar to empty parvovirus capsids. These proteins were used as antigens in enzyme-linked immunosorbent assays (ELISAs) to detect anti-MMV or anti-MPV antibodies in the sera of infected mice. Sera from mice experimentally infected with MMV (n = 43) or MPV (n = 35) and sera from uninfected mice (n = 30) were used to evaluate the ELISAs. The MMV ELISA was 100% sensitive and 100% specific in detecting MMV-infected mice, and the MPV ELISA was 100% sensitive and 98.6% specific in detecting MPV-infected mice. Both assays outperformed a parvovirus ELISA that uses a recombinant nonstructural protein (NS1) of MMV as antigen. The MMV rVP2 and MPV rVP2 proteins provide a ready source of easily produced antigen, and the ELISAs developed provide highly accurate, high-throughput assays for the serodiagnosis of MMV and MPV infections in laboratory mice.

We examined the effects on female CD-1 mice of fetal exposure to low doses of the drug diethylstilbestrol (DES) (0.1 microg/kg/day) and the insecticide methoxychlor (MXC) (10 microg/kg/day) as well as 1000-fold higher doses: 100 microg/kg/day DES and 10,000 microg/kg/day MXC. Pregnant females were administered these chemicals on gestation days 12-18. At 7-8 months of age, female offspring were ovariectomized and implanted for 7 days with a Silastic capsule containing estradiol. Relative to controls, females exposed to the 0.1 microg DES dose showed significantly heavier uteri, while females exposed to the 100 microg DES dose showed significantly lighter uteri. Females exposed prenatally to the 10 microg/kg dose of MXC had significantly heavier uteri relative to females exposed to the 10,000 microg/kg dose of MXC, but neither group differed significantly from controls. Liver weight for females exposed to both doses of DES was significantly greater than controls. Using a microarray approach to analyze DNA methylation, an increase in ribosomal DNA (rDNA) methylation was observed. Sequence data and Southern analysis indicate an increase in 18S rDNA and 45S pre-rDNA methylation in uterine samples exposed prenatally to low and high doses of DES. We thus found opposite effects of fetal exposure to a low and a high dose of DES on the uterine response to estradiol (inverted-U dose-response relationship). In contrast, there was a monotonic dose-response relationship found for prenatal DES exposure on both liver weight and ribosomal DNA hypermethylation.

Cilia-associated respiratory (CAR) bacillus is an unclassified, gram-negative, extracellular bacterium that causes chronic respiratory tract disease in rodents. Infected mice develop microscopic lesions characterized by a primary lymphocytic response followed by macrophage and neutrophilic infiltration. To characterize the lymphocytic subsets that respond to CAR bacillus infection, BALB/c mice were inoculated with 10(5) CAR bacillus bacteria. At seven weeks after inoculation, mice were euthanized and the tracheobronchiolar and hilar lymph nodes were collected and stained for cell surface markers to T cells (CD3, CD4, and CD8), B cells (B220, CD5), natural killer (NK) cells (pan-NK) and intracellular interleukin 10 (IL-10) and interferon-gamma (IFN-gamma). Flow cytometric analysis of lymph nodes from CAR bacillus-infected mice revealed 11% increase in frequency of B cells (R220+), 12% increase in the frequency of double-negative (CD4-CD8-CD3+) T cells, and slight increase in the B-1 subset of B cells (B220+CD5+). There was no change in the frequency of NK cells. The CAR bacillus-infected mice had an overall decrease in the frequency of T cells. Intracellular cytokine staining revealed distinct populations of T cells producing IL-10 and IFN-gamma, and IL-10 production from B cells; NK cells were not a substantial source of IFN-gamma. To our knowledge, this is the first characterization of lymphocytic responses and suggestion that B cells and double-negative T cells may be principally responsible for the lesions associated with CAR bacillus infection.

Two from a group of approximately 50 C.B-17 scid-bg mice were examined because of lethargy, dehydration, and rough coat. Three months prior to development of clinical signs of disease, mice of this study had been surgically implanted with fetal bovine liver, thymus, and lymph node. At necropsy, marked splenomegaly and mild hepatomegaly were observed in both animals. Large areas of necrosis and inflammation, with associated intracytoplasmic granular basophilic inclusions, were observed in histologic sections of multiple organs. Aerobic and anaerobic culturing of the liver yielded negative results. Six months after the initial case, four more reconstituted scid-bg mice from a different fetal donor had identical clinical, gross, and histologic signs of disease. To determine whether the basophilic inclusions represented an infective agent, 4-month-old immune-naive C.B-17 scid-bg mice were inoculated intraperitoneally with a liver and spleen homogenate from an affected mouse. Two weeks after inoculation, mice developed clinical signs of disease and lesions identical to those seen in the signal mice. On ultrastructural examination of the liver, pleomorphic bacteria were found in large cytoplasmic vacuoles of hepatocytes. Bacterial DNA was amplified from the liver, using primers that amplify a segment of the 16S rRNA gene from many bacterial species. Sequencing of the polymerase chain reaction (PCR) product revealed gene sequence identical to that of Coxiella burnetii, the agent of Q-fever. These results highlight the need to consider infective agents of the donor species when working with xenografted animals.

An approximately 8-week-old pet Syrian hamster (Mesocricetus auratus) with a 1-week history of dyspnea, hyporexia, and ataxia was submitted for necropsy. On gross examination, the hamster had multiple abdominal adhesions and enlargement of the mesenteric lymph node. Histologic evaluation revealed multicentric lymphoma of the liver, jejunum, mesenteric lymph node, testicular fat pad, and epididymis. Based on the hamster's age and the type and distribution of the lymphoma, a presumptive diagnosis of hamster polyomavirus-induced lymphoma was made. A specific polymerase chain reaction (PCR) was developed, which confirmed the diagnosis. An in situ PCR demonstrated hamster polyomavirus DNA within lymphocytes of the multicentric lymphoma and renal tubular epithelial cells and within clusters of enterocytes in the jejunum. These data are consistent with environmental dissemination of hamster polyomavirus virions through the renal tubular epithelium and into the urine and with fecal shedding of hamster polyomavirus virions; however, additional studies will be needed to confirm these observations.

The cilium-associated respiratory (CAR) bacillus is a gram-negative, extracellular bacterium that causes persistent respiratory tract infections in rodents. We have previously demonstrated that BALB/c mice are more susceptible to CAR bacillus-induced disease than resistant C57BL/6 mice, with elevations in pulmonary gamma interferon (IFN-gamma) and interleukin (IL)-4. IL-10 is a type 2 cytokine that can increase host susceptibility to bacterial diseases through its anti-inflammatory effects, including suppression of macrophage function. The purpose of this study was to further describe the cytokine profiles associated with histologic lesions in CAR bacillus-infected mice and to assess the effects of cytokine depletion on the pathogenesis of disease. Six-week-old female BALB/c and C57BL/6 mice and mice with targeted mutations in IFN-gamma and IL-4 were inoculated intratracheally with 10(5) CAR bacillus organisms, and samples were collected at 6 to 7 weeks postinoculation. Lung samples were collected for histopathologic examination and analysis of cytokine mRNA. IFN-gamma, IL-10, and IL-4 mRNA levels in the lungs of infected mice were semiquantitatively measured using a reverse transcriptase-mediated PCR assay and compared to those in uninfected control animals of each strain. BALB/c mice infected with CAR bacillus had a median lung lesion score of 6 and IL-10 and IL-4 mRNA levels were significantly elevated. The majority of C57BL/6 mice were resistant to disease characterized by lung lesions scores of 2 or less and a dominant IFN-gamma mRNA cytokine profile. A few C57BL/6 mice with lesions scores of 5 or greater had elevations in all three cytokines and were susceptible to disease. C57BL/6 IFN-gamma knockout mice had increased disease with elevations in IL-10 and IL-4 mRNA, while BALB/c IL-4 knockout mice infected with CAR bacillus had a mild decrease in lesion severity and an attenuated IL-10 mRNA expression compared to wild-type BALB/c mice. These data indicate that IL-10 and IL-4 predominate in CAR bacillus-induced histologic lesions in mice, while IFN-gamma may play a role in resistance to disease.

The cilium-associated respiratory (CAR) bacillus is a gram-negative, gliding bacterium that causes persistent respiratory tract infections in rodents despite histologic and serologic evidence of a marked immune response. To assess humoral immunity and cytokine responses in CAR bacillus disease, 6-week-old female BALB/c and C57BL/6 mice were inoculated intratracheally with 10(5) CAR bacillus organisms. CAR bacillus-specific serum immunoglobulins (immunoglobulin M [IgM], IgG1, IgG2a, IgG2b, IgG3, and IgA) and local pulmonary cytokines (tumor necrosis factor alpha [TNF-alpha], gamma interferon [IFN-gamma], and interleukin-4 [IL-4]) were evaluated by enzyme-linked immunosorbent assay every 7 days for 49 days. BALB/c mice developed CAR bacillus-induced lesions early in the course of disease that became more severe with time. Correlating with increasing disease severity, BALB/c mice had elevations in all antibody isotypes tested, and elevations in pulmonary TNF-alpha, IFN-gamma, and IL-4. C57BL/6 mice developed mild lesions with mild increases in serum IgM, IgG1, IgG2b, and IgG3 levels and minimally detectable IgG2a and IgA. Cytokine perturbations were not detected in C57BL/6 mice. The persistence of infection in BALB/c mice with vigorous serum antibody responses and increased IFN-gamma and IL-4 responses suggests that humoral immunity and T-cell responses are ineffective at preventing CAR bacillus disease. Furthermore, the lackluster antibody responses and undetectable cytokine responses in C57BL/6 mice suggest that humoral immunity and T-cell responses are not critical in resistance to CAR bacillus-induced disease.

Clostridium piliforme is an obligate intracellular bacterium that causes enterohepatic disease in many animal species. C. piliforme infections are commonly subclinical in laboratory rats and mice, and little is known about host regulation of disease or of the effects of C. piliforme infections on investigations that use subclinically infected animals. To assess host regulation of subclinical C. piliforme infections and the effects of those infections on laboratory mice, the expression of the pro-inflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) was evaluated at 0, 1, 3, 7, 14 and 28 days after inoculation with C. piliforme. Subclinical infection was induced in weanling C. piliforme-susceptible DBA/2 or -resistant C57BL/6 mice with either a toxic or a non-toxic C. piliforme strain. Hepatic lesions and bacteria were demonstrated histologically in both mouse strains for 14 days after inoculation with the toxigenic bacterial strain, but were never demonstrated histologically following inoculation with the non-toxigenic strain. Hepatic TNF-alpha and IFN-gamma mRNA and serum protein levels were similarly elevated in both mouse strains 1 day after inoculation with both C. piliforme strains, as evaluated by reverse transcription PCR and enzyme-linked immunosorbent assays, respectively. Elevation of IFN-gamma persisted for 14 days after inoculation; TNF-alpha remained elevated at 28 days after inoculation.

A spiral-shaped bacterium with bipolar, single, nonsheathed flagella was isolated from the feces of Syrian hamsters. The bacterium grew as a thin spreading film at 37 degrees C under microaerobic conditions, did not hydrolyze urea, was positive for catalase and alkaline phosphatase, reduced nitrate to nitrite, did not hydrolyze hippurate, and was sensitive to nalidixic acid but resistant to cephalothin. Sequence analysis of the 16S rRNA gene and biochemical and phenotypic criteria indicate that the novel bacterium is a helicobacter. The novel bacterium is most closely related to the recently described mouse enteric helicobacter, Helicobacter rodentium. This is the first urease-negative Helicobacter species with nonsheathed flagella isolated from feces of asymptomatic Syrian hamsters. We propose to name this novel helicobacter Helicobacter mesocricetorum. The type strain is MU 97-1514 (GenBank accession number AF072471).

Clostridium piliforme is an obligately intracellular bacterium that causes enterohepatic disease in many domestic and laboratory animal species. Susceptibility to infection is known to vary with the host immune status, species and strain, but little is known about specific immune mechanisms that regulate this disease. Subclinical infection was induced in weanling C. piliforme-susceptible DBA/2 or resistant C57BL/6 mice with either a toxic or a non-toxic C. piliforme isolate. Hepatic lesions and bacteria were evident in both mouse strains for 14 days after inoculation with the toxigenic bacterial isolate, but were never demonstrated following inoculation with the non-toxigenic isolate. All mice demonstrated increased interleukin-6 (IL-6) levels that were largely independent of host strain susceptibility to infection or virulence of the bacterial isolate. The severity of C. piliforme-induced hepatic lesions was increased by polyclonal anti-IL-6 treatment in both resistant (DBA/2) and susceptible (C57BL/6) mouse strains. These data indicate that IL-6 is important in mediating the course of murine C. piliforme infections but is not involved in determining host susceptibility to acute infection, nor is it influenced by the virulence of the C. piliforme isolate.

Background and Purpose: Several rodent helicobacters have been associated with chronic active hepatitis or inflammatory bowel disease. Severe combined immunodeficient (SCID) mice appear to be inherently susceptible to disease attributable to these emerging pathogens. With the advent of polymerase chain reaction (PCR) analysis, it has become clear that several as yet unidentified Helicobacter species may also colonize rodents, but their capacity to cause disease is unknown., Methods: A Helicobacter species isolated from feces of a BALB/c mouse and provisionally named "H. typhlonicus" was used to inoculate helicobacter-free 4-week-old SCID mice (n = 11 males and 11 females). At various weeks after inoculation, mice were sacrificed and liver and intestinal specimens were collected for histologic examination and PCR analyses., Results: The C.B-17 scid/scid mice inoculated with "H. typhlonicus" developed moderate to severe proliferative typhlocolitis, similar to that seen in SCID mice infected with H. hepaticus or H. bilis. However, in contrast to mice infected with H. hepaticus or H. bilis, lesions of chronic active hepatitis were not detected in mice inoculated with "H. typhlonicus." A similar disease syndrome developed in SCID mice cohabitated with B6D2F1 mice naturally infected with a novel Helicobacter species that was genetically identical to "H. typhlonicus.", Conclusion: "Helicobacter typhlonicus" joins a growing list of helicobacters that are capable of inducing enteric disease in immunodeficient mice.

Helicobacter hepaticus is a bacterial pathogen that causes chronic active hepatitis and inflammatory bowel disease in mice. The purpose of this study was to develop a recombinant antigen-based enzyme-linked immunosorbent assay (ELISA) to detect H. hepaticus-infected mice. A genomic library of H. hepaticus was constructed and was screened with sera from H. hepaticus-infected mice. A 459-bp open reading frame that coded for an 18-kDa immunoreactive protein, MAP18, was identified. The gene had high identity with genes coding for outer membrane proteins of other bacteria, and the predicted amino acid sequence of MAP18 had a putative membrane-trafficking signal sequence and a putative signal peptidase II cleavage site. The recombinant protein was expressed in Escherichia coli as a glutathione S-transferase (GST) fusion protein, GST-MAP18, and purified by affinity chromatography. The 44-kDa fusion protein was detected on Western blots probed with sera from H. hepaticus-infected mice but was not detected on blots probed with sera from mice infected with Helicobacter muridarum or Helicobacter bilis or with sera from mice free of Helicobacter infection. The GST-MAP18 fusion protein was used as an antigen in an ELISA to detect anti-H. hepaticus antibodies in sera from infected mice. This ELISA was compared to an H. hepaticus-specific ELISA that uses a detergent extract of H. hepaticus as the antigen. Sera from mice naturally and experimentally infected with H. hepaticus, H. bilis, or H. muridarum and sera from mice free of Helicobacter infection were evaluated. Both ELISAs performed with a high specificity (98%); however, the detergent extract-based ELISA performed with a higher sensitivity (89%) than the recombinant protein-based ELISA (sensitivity, 66%). These data indicate that H. hepaticus carries a gene that encodes an immunogenic 18-kDa membrane-associated protein; however, antibodies to this protein are not detected in all infected mice.

Clostridium piliforme induces enterohepatic disease in many domestic and laboratory animal species. Susceptibility to infection is known to vary with the immune status and strain of the host, but little is known about specific immune mechanisms that regulate this disease. To evaluate host control of C. piliforme infection, we examined the role of interleukin-12 (IL-12) both in the control of and in the response to murine C. piliforme infection. For this study, 3-week-old C. piliforme-resistant C57BL/6 or -susceptible DBA/2 mice were infected intravenously with either the toxic H1 or the nontoxic M1 C. piliforme isolate. Serum and liver samples were collected prior to C. piliforme inoculation (day 0) and at days 1, 3, 7, 14, and 28 postinoculation. Evaluation of hepatic IL-12 p40 mRNA expression by reverse transcription-PCR and of total-IL-12 protein levels in serum by enzyme-linked immunosorbent assay revealed that C. piliforme induced elevations in both hepatic p40 mRNA and serum total-IL-12 levels at all times postinoculation. Elevations were similar with both toxic and nontoxic C. piliforme isolates. Levels of total IL-12 in serum were significantly (P < 0.05) higher in C57BL/6 mice than in DBA/2 mice. Additional experiments were performed in which polyclonal antibody treatment was used to neutralize IL-12 in mice of both strains prior to intravenous inoculation with toxic C. piliforme H1. IL-12 neutralization increased the severity of Tyzzer's disease at day 3 postinoculation in both mouse strains, but the degree of increase was greater in C57BL/6 mice than in DBA/2 mice.

Helicobacter bilis is a recently identified species that colonizes the intestine and liver of mice. In immunocompetent mice, infections have been associated with mild hepatitis, and in immunocompromised mice, inflammatory bowel disease has been induced by intraperitoneal inoculation of the organism. We report inoculation of 6-week-old C.B-17 scid/scid mice by gastric gavage with approximately 10(7) H. bilis colony-forming units. Groups of mice were euthanized and necropsied 12, 24, and 36 weeks after inoculation. Mild to moderate proliferative typhlitis was evident in all mice at 12 and 36 weeks after inoculation and in most mice 24 weeks after inoculation. Mild to severe chronic active hepatitis was detected in 10 of 10 male mice and 3 of 10 female mice. These results indicate that H. bilis can cause moderate to severe enterohepatic disease in immunocompromised mice.

Mouse monoclonal antibodies (MAbs) developed to a rat isolate (R-3) of cilia-associated respiratory (CAR) bacillus were used to assess antigenic relationships among three rat and five rabbit CAR bacillus isolates. Evaluation of MAbs by enzyme-linked immunosorbent assays (ELISAs) indicated that 87 of 241 hybridomas secreted CAR bacillus-reactive antibodies that could be grouped into four major groups. Group-I MAbs reacted with epitopes expressed by all CAR bacillus isolates and at least two or more nonrelated species of bacteria. Group-II, -III, and -IV MAbs reacted with only one or more of the rat CAR bacillus isolates; no MAbs reacted only with rat and rabbit CAR bacillus isolates. Western blot analyses indicated that 41-, 50-, and 105-kDa peptides of rat CAR bacillus isolates expressed rat CAR bacillus group- and isolate-specific epitopes. Hyperimmune anti-CAR bacillus antiserum and serum specimens from a CAR bacillus histologically positive mouse and rat also reacted with the 41-, 50-, and 105-kDa peptides. Sera from CAR bacillus histologically negative rats did not react with these peptides. These results suggest that the 41-, 50-, and 105-kDa peptides may represent suitable antigens for development of a specific ELISA for detection of rodent CAR bacillus infections. Furthermore, these data indicate that use of crude CAR bacillus preparations for either rat or rabbit CAR bacillus ELISAs is inappropriate.

Proliferative lymphocytic tracheitis and pneumonia were observed histologically in the respiratory tract of a captive Burmese python (Python molurus bivittatus). A mycoplasma species was isolated from the respiratory tissue. Polymerase chain reaction analysis of the 16S rRNA gene sequence of the isolate showed 0.90 similarity to Mycoplasma agassizii, an organism previously shown to cause respiratory disease in reptiles. Based on these findings, a novel Mycoplasma species was suspected to be the causative agent of respiratory disease in this snake.

Hyperplastic goiter was diagnosed during routine health monitoring of a closed Syrian hamster colony (SG). Adult and juvenile hamsters were affected at a prevalence of 45%. Histologic examination of the enlarged thyroid gland revealed marked follicular cell hyperplasia. Because prevalence of thyroid hyperplasia in this colony exceeded the 6 to 7% prevalence expected in aged hamsters, additional studies were performed to investigate the pathogenesis of this condition. Juvenile male SG hamsters and age- and sex-matched Syrian hamsters that did not have increased prevalence of goiter were obtained from an unrelated source (Fredrick Cancer Research and Development Center [FCRDC]). The thyroid glands of hamsters were evaluated by 123I radionuclide imaging. Eight of 18 SG hamsters and none of the FCRDC hamsters had a diagnosis of enlarged thyroid gland. Serum baseline and post-thyrotropin thyroxine concentrations in SG hamsters were not statistically different from those in FCRDC hamsters. To investigate whether diet played a role in development of hyperplastic goiter, for 6 months 15 FCRDC hamsters were fed the diet that had been fed to SG hamsters (mouse breeder diet), and five were fed a control diet. To determine whether dietary change would result in resolution of goiter, affected SG hamsters were fed a control diet for 3 months. At the end of each feeding trial, thyroid gland uptake of 123I was reevaluated. The amount of 123I taken up by the thyroid glands of FCRDC hamsters fed the mouse breeder diet was not significantly different from that of controls. In contrast, thyroid gland uptake of 123I remained high for all affected SG hamsters fed the control diet. On the basis of results of these investigations, diet was ruled out as the cause of goiter. Also, a diagnosis of euthyroid hyperplastic goiter was made for the SG hamsters. A genetic cause is suspected to play a role in the increased prevalence of goiter in SG hamsters.

Clostridium piliforme infection (Tyzzer's disease) induces enterohepatic disease in many domestic and laboratory animals. Murine susceptibility to Tyzzer's disease varies with host strain, age, and immune status However, little is known about the role of the immune system in control of this disease. To investigate the role of host immunity in Tyzzer's disease, mice were depleted of either neutrophils, natural killer cells, or macrophages by antibody administration or chemotherapy. After depletion, DBA/2 mice, which are naturally susceptible to C. piliforme, or naturally resistant C57BL/6 mice were inoculated intravenously with C. piliforme. Animals were euthanized 3 days postinoculation and evaluated for gross and histologic lesions and hepatic bacterial load. In juvenile DBA/2 or C57BL/6 mice, depletion of either neutrophils or natural killer cells increased severity of disease. In adult mice, depletion of natural killer cells significantly increased severity of Tyzzer's disease in the resistant (C57BL/6) but not in the susceptible (DBA/2) strain. Macrophage depletion did not alter the course of infection in either mouse strain. These studies indicate an important role for neutrophils and natural killer cells in the pathogenesis of murine Tyzzer's disease. The role of macrophages in murine C. piliforme infection will require further evaluation.

A fecal PCR assay for detection of Helicobacter infections in laboratory rodents was developed. DNA was isolated from murine fecal pellets, and a region of the 16S rRNA gene conserved among murine Helicobacter species was amplified. The fecal PCR was sensitive and specific. This assay does not require euthanasia of rodents, which is especially important for valuable rodents, such as transgenic mice.

Helicobacter hepaticus is a newly recognized bacterium associated with chronic active hepatitis, hepatic carcinoma, and inflammatory bowel disease in mice. Currently, fecal or tissue PCR, fecal culture, or histologic examination of silver-stained liver sections is used to diagnose H. hepaticus infection. In this report, we describe an enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of H. hepaticus infection in mice with a membrane digest preparation of H. hepaticus as the antigen. Sera from mice positive for H. hepaticus by PCR or histologic examination (n = 88), positive for Helicobacter bilis by PCR (n = 13), positive for other helicobacters (not identifiable to species level) by PCR (n = 25), or negative for all Helicobacter species by PCR (n = 162) were used to evaluate the ELISA. Results indicated that ELISA provided 93.2% sensitivity, 94% specificity, 87.2% positive predictive value, and 96.9% negative predictive value. Cross-reactive antibodies were detected in some mice infected with helicobacters not identifiable to species level. To further define ELISA sensitivity and specificity, groups of 10 C57BL/6 mice were inoculated per os with H. hepaticus, Helicobacter muridarum, or H. bilis. Sera were collected and examined by the ELISA. H. hepaticus-infected mice seroconverted by 2 weeks and maintained ELISA reactivity throughout the 18-week study, while mice infected with H. muridarum and H. bilis were negative by ELISA. These results indicate that this reported ELISA is highly sensitive and specific for the serodiagnosis of H. hepaticus infection in mice.

A filamentous, gram-negative, motile bacterium with a single polar sheathed flagellum was isolated from gallbladders of hamsters with cholangiofibrosis and centrilobular pancreatitis. Bacteria grew under microaerophilic conditions at 37 and 42 degrees C, were oxidase, catalase, arginine aminopeptidase, and L-arginine arylamidase positive, reduced nitrate to nitrite, were resistant to cephalothin, and exhibited intermediate susceptibility to nalidixic acid. Sequence analysis of the 16S rRNA gene indicated that the bacterium was a novel member of the Helicobacter genus, most closely related to Helicobacter pametensis. We propose to name this bacterium Helicobacter cholecystus. In epidemiologic studies, isolation of H. cholecystus correlated strongly with the presence of cholangiofibrosis and centrilobular pancreatitis; however, further studies are needed to define the role of this bacterium in pathogenesis.

Ninety-seven BALB/c mice were inoculated intravaginally with 8.0 x 10(5) Tritrichomonas foetus organisms, using either isolate ATCC 30003 or field isolate MU Y22 2 days after estrogenization with 15 micrograms 17 beta-estradiol. Reproductive tracts were examined at several time points post-inoculation to determine gross and histologic responses to trichomonad infection as compared to estrogenized, uninfected control animals. The two isolates varied greatly in ability to maintain chronic infection; no ATCC 30003-inoculated animals remained culture-positive beyond 7 weeks post-inoculation, whereas MU Y22-inoculated animals were infected for greater than 26 weeks. Lesions were seen in 40-60% of animals prior to 10 weeks post-inoculation and included moderate uterine dilation and glandular atrophy, uterine gland abscesses, pyometra, intramural perivascular lymphoid infiltrates, and ovarian bursitis. The severity of lesions was independent of the T. foetus isolate. Lesions became more severe at 10 weeks post-inoculation, and at 10 and 26 weeks post-inoculation, lesions were seen in 60% and 75% of animals, respectively. In addition to lesions described above, epithelial changes were marked at these late necropsies, including ulceration, flattening, hypertrophy, and squamous metaplasia. The lesions seen in these mice closely resemble those described in natural bovine infection, suggesting that the estrogenized BALB/c mouse is an excellent model for study of bovine trichomoniasis.

Several autonomous rodent parvoviruses distinct from the prototypic rodent parvoviruses have been isolated. These include variants of a mouse parvovirus (MPV), a hamster isolate designated hamster parvovirus (HaPV), and a variant strain of minute virus of mice (MVM) designated MVM-Cutter or MVM(c). In this study, the DNA sequence of the coding regions of the viral genome and the predicted protein sequences for each of these new isolates were determined and compared to the immunosuppressive and prototypic strains of MVM [MVM(i) and MVM(p)], the rodent parvovirus H-1, and LuIII, an autonomous parvovirus of uncertain host origin. Sequence comparisons showed that the MPV isolates were almost identical, HaPV was very similar to MPV, and MVM(c) was most similar to MVM(i) and MVM(p). Haemagglutination inhibition assays revealed that MPV and HaPV represent two serotypes distinct from previously characterized rodent parvovirus serotypes while MVM(c) belongs to the MVM serotype. Each of the newly isolated rodent parvoviruses was shown to encapsidate a predominantly negative-sense 5 kb DNA genome and to encode two nonstructural proteins (NS1 and NS2) and two structural viral proteins (VP1 and VP2). These studies indicate that MPV and HaPV are autonomous parvoviruses distinct from previously characterized parvoviruses and MVM(c) is a variant strain of MVM distinct from MVM(i) and MVM(p).