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C Besch-Williford

Publications and source records attributed to C Besch-Williford.

At least 19 recordsLinked to original sources
PubMed2007

Morphologic and histologic comparisons between in vivo and nuclear transfer derived porcine embryos.

Nuclear transfer (NT) is an inefficient but invaluable tool of the biotechnology industry. This study looked at abnormalities associated with peri-implantation NT porcine embryos. Four experimental groups were examined: nonpregnant animals, in vivo pregnant animals, NT recipients, and manipulation control embryos (MC). Embryos (Day 10, 12, or 14) were evaluated for embryonic disc diameter, gross morphology, nucleoli density, and mitotic figure index. Day 12 (P < or = 0.03) and Day 14 (P < or = 0.01) NT embryos had increased numbers of nucleoli, and Day 14 NT embryos had an increased (P < or = 0.03) mitotic index compared to in vivo and MC embryos. In vivo produced Day 14 embryos had increased (P < or = 0.01) disk diameters when compared to other embryos except for MC Day 14, which also showed increases (P < or = 0.01) in disk diameter except when compared to in vivo produced Day 12 and Day 14 embryos. In vivo produced Day 12 had greater (P < or = 0.03) disk diameters when compared to NT and MC embryos except for MC Day 14, and in vivo produced Day 14 embryos, which had a significantly increased (P < or = 0.01) disk diameter. In vivo produced Day 14 embryos were morphologically more advanced (P < or = 0.01) than Day 14 NT and MC counterparts. NT embryos develop at a slower rate than their in vivo produced counterparts. The increase in nucleoli and mitotic index of NT embryos suggest the cell cycle may be affected or the NT embryos are employing other means to compensate for slow development. The techniques used during NT also appear to compromise embryo development.

Animals↗
PubMed2001

Dietary genistein increased DMBA-induced mammary adenocarcinoma in wild-type, but not ER alpha KO, mice.

Dietary supplements containing concentrates of plant-derived estrogens are being increasingly used by consumers as alternatives for hormone replacement therapy, for treatment of menopausal symptoms, and as cancer preventives. The effect of dietary genistein on dimethylbenz[a]anthracene (DMBA)-induced mammary tumor development was investigated in wild-type (ER alpha WT) and estrogen receptor-alpha knockout (ER alpha KO) mice. ER alpha WT and ER alpha KO mice were fed a casein-based diet containing 0 or 1 g genistein/kg diet from weaning. Tumors were induced by oral administration of DMBA and subscapular implantation of medroxyprogesterone acetate. No tumors were observed in ER alpha KO mice. In ER alpha WT mice, dietary intake of genistein influenced tumor development, enhancing anaplasia of mammary cancer. Mice consuming genistein expressed malignant mammary adenocarcinoma, whereas benign adenomas were observed in mice fed the control diet. Dietary intake was also influenced by genistein, with ER alpha WT and ER alpha KO mice fed genistein consuming less food (p < 0.0001) and subsequently weighing less than mice fed the control diet (p < 0.0001). Significant differences in food intake by genotype were also observed (p = 0.0017), with ER alpha KO mice consuming less than ER alpha WT mice. Overall, this study found no protective effect of genistein on DMBA-induced mammary tumors in mice and suggests a potential adverse effect on tumor development when high levels of genistein are consumed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

Diagnostic polymerase chain reaction assays for identification of murine polyomaviruses in biological samples.

PURPOSE: Mouse polyoma virus and K virus are murine polyomaviruses frequently used in carcinogenicity and cellular biology studies in mice. These viruses can cause persistent infections, which increase the likelihood of transmission through transplantation of cells from infected mice. To identify polyomavirus-infected biological samples, several diagnostic polymerase chain reaction (PCR) assays were developed. METHODS: Polyomavirus-family and virus-specific PCR assays were designed and optimized for specificity and sensitivity. The generic (polyomavirus-family) PCR assay and mouse polyoma virus-specific assays were compared with the mouse bioassay for diagnosis of infected cellular samples. RESULTS: Specificity of the PCR assays was confirmed by testing a battery of other murine viruses. The mouse polyoma virus PCR test was the most sensitive assay, detecting as few as 2,000 copies of homologous virus. The K virus PCR assay was about eightfold less sensitive, and the generic PCR test was the least sensitive. Mouse polyoma virus and generic PCR assays amplified mouse polyoma virus in the inoculum and tissues from experimentally infected mice, and performed better than did the mouse bioassay. CONCLUSIONS: Results of this study confirm that PCR is a specific and sensitive method for detection of murine polyomaviruses in biological samples.

Animals↗
PubMed2001

Anatomic and physiologic reference values in least shrews (Cryptotis parva).

BACKGROUND AND PURPOSE: The least shrew is an established animal model for reproductive and pharmacologic research. Biologic reference data are needed to assess animal health status and provide a rationale for use of novel statistical programs to evaluate the effects of orally administered substances in toxicologic and pharmacologic studies. METHODS: Organ weights, blood biochemical and hematologic values, and food and water consumption data were collected from 50-day-old shrews after two weeks' consumption of a standard feline diet. RESULTS: In general, data correlated well with values reported for other mammalian species. Plasma phosphorus concentration was high. There was a significant difference in food and water consumption per gram of body weight between shrews at lower and upper (+/- 1 SD) weight ranges for the study. The 3.2-g animals consumed 27% more food per gram of body weight than did the 5.0-g animals. CONCLUSIONS: The high phosphorus concentration was attributed to hemolysis resulting from the axillary cut method of blood sample collection. The small size of the shrew allowed demonstration of the Kleiber effect within a +/- 1 SD weight range in a single species. The phenomenon necessitates the use of statistical methods other than the typical tests establishing the significance of the differences between the means of groups for oral toxicologic and pharmacologic studies.

Animals↗
PubMed2000

Centrosome-centriole abnormalities are markers for abnormal cell divisions and cancer in the transgenic adenocarcinoma mouse prostate (TRAMP) model.

We utilized the transgenic adenocarcinoma mouse prostate (TRAMP) model to study the formation of abnormal mitosis in malignant tumors of the prostate. The results presented here are focused on centrosome and centriole abnormalities and the implications for abnormal cell divisions, genomic instability, and apoptosis. Centrosomes are microtubule organizing organelles which assemble bipolar spindles in normal cells but can organize mono-, tri-, and multipolar mitoses in tumor cells, as shown here with histology and electron microscopy in TRAMP neoplastic tissue. These abnormalities will cause unequal distribution of chromosomes and can initiate imbalanced cell cycles in which checkpoints for cell cycle control are lost. Neoplastic tissue of the TRAMP model is also characterized by numerous apoptotic cells. This may be the result of multipolar mitoses related to aberrant centrosome formations. Our results also reveal that centrosomes at the poles in mitotic cancer cells contain more than the regular perpendicular pair of centrioles which indicates abnormal distribution of centrioles during separation to the mitotic poles. Abnormalities in the centriole-centrosome complex are also seen during interphase where the complex is either closely associated with the nucleus or loosely dispersed in the cytoplasm. An increase in centriole numbers is observed during interphase, which may be the result of increased centriole duplication. Alternatively, these centrioles may be derived from basal bodies that have accumulated in the cell's cytoplasm, after the loss of cell borders. The supernumerary centrioles may participate in the formation of abnormal mitoses during cell division. These results demonstrate multiple abnormalities in the centrosome-centriole complex during prostate cancer that result in abnormal mitoses and may lead to increases in genomic instability and/or apoptosis.

Adenocarcinoma↗
PubMed1997

Unique Salmonella choleraesuis surface protein affecting invasiveness. Possible inv related sequence.

TnphoA mutagenesis of a Salmonella choleraesuis isolate recovered from septicemic infection of feeder pigs resulted in 56 PhoA+ KnR StrR mutants. Thirty-five mutants exhibited reduced levels of invasion in the Hep-2 cell model and were examined by SDS-PAGE Western Blot analysis using an anti-alkaline phosphatase antibody to visualize the insertion gene products. A mutant which produced a gene fusion product of 95 kDa and exhibited > 90% reduction in invasion was subcloned. A 10 Kb BamHI fragment of the chromosome containing the phoA insert was detected by hybridization and cloned into a pGEM vector. The resulting 1657 base sequence contained a 1104 bp ORF with two short regions of homology with S. typhimurium invF and invG. one region of homology with lcrD of Yersinia pseudotuberculosis but contained largely unique sequences not contained in Gene Bank. The full length sequence was not obtained as there was no stop codon detected. The % G+C was 44%, considerably lower than that of the Salmonella chromosome, but compatible with the proposed Yersinia origin of the inv genes. The NH2 387 a.a. sequence includes 5 transmembrane regions, resembling the model derived from the hydrophobicity plot of S. typhimurium InvA.

Antigens, Surface↗
PubMed1996

Identification of murine helicobacters by PCR and restriction enzyme analyses.

Three murine helicobacter species have recently been identified: Helicobacter hepaticus, Helicobacter muridarum, and Helicobacter bilis. Infections with H. hepaticus and H. bilis have been associated with hepatitis and hepatic neoplasia. In this study, oligonucleotide primers were designed from regions of the 16S rRNA gene that are conserved among members of the Helicobacter genus. The assay amplified the expected 374-bp product from all three rodent Helicobacter species and was able to detect as little as 5 pg of H. hepaticus, H. bilis, or H. muridarum DNA. The specificity of the reaction was determined by testing cecal DNA from uninfected mice and mice with documented Helicobacter infections and by testing DNA from other bacterial genera. A product of the expected size was generated with cecal DNA from Helicobacter-infected mice but not with DNA from uninfected mice. With the exception of that of "Flexispira rappini, " which is closely related to the Helicobacter genus, DNA from other bacterial genera was not amplified with the Helicobacter genus-specific primers. MboI, MaeI, and HhaI restriction enzyme analyses of the amplified product were able to differentiate among the murine Helicobacter species but could not differentiate H. bilis from "F. rappini." To distinguish H. bilis, a reverse primer based on H. bilis 16S rRNA sequence was designed. PCR with the H. bilis-specific reverse primer (Hbr) and the Helicobacter genus-specific forward primer (H276f) amplified H. bilis DNA but not DNA from "F. rappini" or other rodent helicobacters. Examination of a large number of murine cecal tissues with this combination of PCR assays and restriction enzyme analyses indicated that H. hepaticus and H. bilis infections are widespread in laboratory mouse and rat colonies.

Animals↗
PubMed1996

Morphophysiologic characterization of peripheral neuropathy in zinc-deficient guinea pigs.

Zinc-deficient guinea pigs develop a peripheral neuropathy characterized by abnormal posture and gait, hyperesthesia, slowed motor nerve conduction velocity (MNCV), and decreased sciatic nerve Na,K-ATPase activity. This study was designed to further investigate longitudinally the morphophysiologic features of the neuropathy. Weanling guinea pigs were fed a low-zinc (<1 mg/kg) diet ad libitum (-ZnAL), an adequate-zinc (100 mg/kg) diet ad libitum (+ZnAL), or the adequate diet restricted in intake ((+ZnRF). Electrophysiologic, morphologic, and biochemical parameters of peripheral nerves were examined at 2.5, 4.0, and 5.5 weeks. Serum zinc was significantly lower by 2.5 weeks and growth rate reduced by 4 weeks in -ZnAL animals. Postural abnormalities were first obvious at 4 weeks, although MNCVs were significantly slower in zinc-deficient animals at all time intervals. The conduction of sensory impulses, as measured by spinal cord somatosensory evoked potentials (sSSEP), was significantly slower in the -ZnAL animals at 5.5 weeks. Examination of teased preparations and histologic sections of sciatic nerves at 5.5 weeks revealed no degenerative lesions or differences in density of myelinated fibers (MF). The size frequency distribution of MF in all groups was unimodal, with a trend toward smaller myelinated nerve fibers in -ZnAL and +ZnRF animals. Sciatic nerve Na,K-ATPase activity in the -ZnAL animals was significantly reduced after 4 weeks of zinc deprivation. At 5.5 weeks, nerve concentrations of myo-inositol, glucose, fructose, and sorbitol were significantly decreased in -ZnAL animals compared with the +ZnRF and +ZnAL controls. The peripheral neuropathy associated with acute zinc deficiency is a parenchymatous axonal disorder characterized by slowed motor and sensory nerve impulse conduction and reduction in nerve Na,K-ATPase activity and nerve concentrations of simple sugars and their metabolites.

Animals↗
PubMed1995

Cerebrospinal larva migrans due to Baylisascaris procyonis in a guinea pig colony.

Four guinea pigs from a colony of approximately 50 animals were examined for progressive neurologic disease of 5 days' duration. Signs of neurologic dysfunction included cachexia, stupor, hyperexcitability, lateral recumbency, and opisthotonos. Results of gross pathologic, microbiologic, and serologic examinations were unremarkable. Histologic examination of cerebral and cerebellar sections revealed multifocal malacia and regions of eosinophilic granulomatous inflammation. Cross-sections of nematode larvae, identified as Baylisascaris sp., most likely B. procyonis, the raccoon ascarid, were seen in the brain of some affected animals. An intact Baylisascaris larva was recovered from a symptomatic animal when cerebral tissue was processed by the Baermann extraction technique. Results of further investigation indicated that wood shavings used for the guinea pigs had been contaminated by raccoon feces, some of which contained numerous B. procyonis eggs. The bedding source for this colony was changed and, to date, no new cases of neurologic disease have been seen. This report emphasizes the potential insidious entrance of B. procyonis into well-managed laboratory animal facilities.

Animals↗
PubMed1994

Detection of cilia-associated respiratory bacillus by PCR.

The cilia-associated respiratory (CAR) bacillus is an unclassified, gram-negative, motile bacterium that has been implicated as an etiologic agent of respiratory disease in laboratory rodents. In the present study, approximately 1,200 bases of the 16S rRNA gene from three CAR bacillus isolates were sequenced. CAR bacillus-specific primers were designed on the basis of the 16S rRNA gene sequence and used in a PCR assay. The PCR assay detected as little as 500 fg of purified CAR bacillus DNA. The expected 267-bp DNA fragment was amplified from respiratory tissue of frozen, formalin-fixed, and paraffin-embedded samples from experimentally and naturally infected rats and mice. In contrast, no product was amplified from respiratory tissues of sham-infected experimental animals or animals that were serologically or histopathologically negative for the CAR bacillus. Our findings indicate that this PCR assay is a rapid, specific, and sensitive detection method for the diagnosis of CAR bacillus infection in rats and mice.

Animals↗
PubMed1992

Evaluation of a subcutaneously implanted chamber for antibody production in rabbits.

Polyclonal antibody production in subcutaneous chambers was compared to traditional antibody production methods in rabbits. The chamber, a sterilized plastic wiffle golf ball that had been surgically implanted in the subcutis of the thoracic region, was immunized via a percutaneous injection of antigen into the core of the ball through one of the perforations in the chamber wall. Rabbits bearing chambers were immunized on the same schedule and with the same concentrations of antigens as were provided the adjuvant injected rabbits. Fluid volumes of 12 to 22 ml could be removed from each chamber at weekly intervals. Chamber antibody to specific microbial antigens was equal to or better than serum antibody produced to the same antigens with Freund's or acrylamide adjuvants. The comfort of the rabbit, the ease in chamber immunization, and the recovery of high titer antibody in large volumes make the subcutaneous chamber an attractive method for polyclonal antibody production.

Animals↗
PubMed1990

Zinc status and peripheral nerve function in guinea pigs.

Guinea pigs fed a diet low in zinc develop clinical signs of apparent neurological origin. The signs include abnormal posture and locomotion as well as hypersensitivity to touch. In this study, electrophysiological and biochemical measurements were made on sciatic nerves from zinc-deficient and repleted animals as well as on controls fed either ad libitum or restricted to maintain weight comparable to those consuming the deficient diet. Both in vivo and in vitro measurements showed decreased motor nerve conduction velocity (NCV) in nerves of deficient animals. A longitudinal study showed excellent correlation of NCV and severity of clinical signs. Nerves from zinc-deficient guinea pigs had decreased Na,K-ATPase activity, but the number of sodium channels, as determined by saxitoxin binding, was not affected. It was concluded that the clinical signs of neuropathy in zinc deficiency are associated with impaired NCV and decreased Na,K-ATPase activity of peripheral nerves. The zinc-deficient guinea pig provides a useful model to study the biochemical defect in a peripheral neuropathy.

Amphibian Proteins↗
PubMed1990

Protein and antigenic heterogeneity among isolates of Bacillus piliformis.

Protein and antigenic heterogeneity among isolates of Bacillus piliformis, the etiologic agent of Tyzzer's disease, were investigated. The seven isolates utilized in this study were originally isolated from naturally infected animals of different animal species and diverse geographical locations. Isolates were propagated in mammalian cell lines, and bacterial extracts were prepared. Protein and antigenic profiles were compared among isolates, using Coomassie blue-stained polyacrylamide gels and Western blot (immunoblot) analyses, respectively. Results showed differences in protein and antigen banding patterns, indicating diversity among isolates. Western blots probed with serum preabsorbed with a heterologous bacterial extract revealed that numerous antigens have different electrophoretic mobilities among isolates but apparently share common epitopes. Immunodominant cross-reactive antigens may be candidate proteins useful for development of improved serologic diagnostic tests, allowing identification of animals infected with a wide range of B. piliformis isolates.

Animals↗
PubMed1990

Zinc deficiency and peripheral neuropathy in chicks.

Zinc-deficient chicks develop an arthritic-like neuromuscular disorder. They walk with a stilted gait and tend to remain in a squat position, bearing little weight on the legs. The purpose of this study was to determine the basis of the syndrome by making electrophysiologic measurements of nerve function. Chicks were fed low zinc (6 mg/kg) and zinc-adequate (50 mg/kg) diets, the latter ad libitum and pair-fed. At the end of 3 weeks, sciatic nerve function was determined in vivo by use of an electrodiagnostic system. Motor nerve conduction velocity was significantly lower in chicks fed the low zinc than in those fed the zinc-adequate diet. Zinc repletion of the 2-week depleted chicks was achieved by feeding the adequate diet for 2 weeks. Repletion for this period cured clinical signs and restored nerve conduction velocity to normal, but reversal did not occur within 1 week. It was concluded that the abnormal posture and locomotion of zinc deficiency are associated with peripheral neuropathy.

Animals↗