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Biomedical subjects

R C Bayer

Publications and source records attributed to R C Bayer.

At least 19 recordsLinked to original sources
PubMed1981

Influence of short term fasting on chicken alimentary canal mucosa.

Little is known about the physiological effects of short-term fasting in avian species. The present study was developed to examine the alimentary mucosal changes in fasted birds by scanning and transmission electron microscopy. Chickens of various ages were fasted for periods of 3, 5, and 7 days. Water was provided ad libitum. At the end of the fasting periods the birds were sacrificed along with ad libitum fed controls. Tissue samples from crop, duodenum, and ileum were processed by standard methods for scanning and transmission electron microscopy (SEM and TEM). The SEM samples were prepared by vacuum drying methods. The TEM samples were embedded in Spurrs embedding medium. Mucosal sloughing was observed in the crop and small intestine with SEM only in fasted birds. With TEM, separation was observed between the mucosal cells of fasted birds with membranous whorls in these spaces. Sloughed cells may be an endogenous protein source for the fasting bird.

Animals↗
PubMed1979

A rapid technique for preparing microorganisms for transmission electron microscopy.

A rapid and efficient method of preparing microorganisms for transmission electron microscopy is reported. In developing the method Salmonella, streptococcal, and protozoal specimens were fixed with glutaraldehyde. After fixation cells are collected on a membrane filter, washed with buffer, postfixed with osmium tetroxide, then washed with distilled water and stained en bloc with uranyl acetate. Specimens are dehydrated using a graded series of acetone and then infiltrated with graded mixtures of acetone and Spurr embedding medium. Finally the membrane filter is cut into small pieces and embedded in fresh embedding medium polymerized in polyethylene capsules. By collecting and processing the specimens on membrane filters, numerous centrifugations are eliminated from standard procedures. The use of a low viscosity embedding medium allows for rapid infiltration and embedding of the specimen. Using this technique microbial specimens can be sectioned after less than 4 hours preparation.

Animals↗
PubMed1977

Scanning electron microscopy of induced cell rounding of mouse adrenal cortex tumor cells in culture.

The surface topologies of mouse adrenal cortex tumor cells of primary or clonal origin grown as monolayer cell cultures were observed by scanning electron microscopy following their exposure to substances that effect steroid release and/or cell rounding. ACTH induced cell rounding with a concomitant profuse development of fine microvilli in a non-synchronously dividing cell population. This was less pronounced with other steroidogenic substances and absent in EGTA or trypsin-treated cells. Morphological alterations occurred most rapidly with cAMP and least rapidly with dbcAMP. The rapid development of fine microvilli with ACTH is proposed to be a specific hormone mediated response.

Adrenocorticotropic Hormone↗
PubMed1977

Comparison of tracheal histopathology and scanning electron microscopy of infectious laryngotracheitis.

Samples of trachea were examined with light microscope, fluorescent microscope, and scanning electron microscopy (SEM). Negative controls and infectious laryngotracheitis (ILT) positive samples were compared. Histopathology illustrated lesions characteristic fo ILT. Lesions seen with SEM suggested surface changes including ciliary disruption. luminal debris, epithelial slough, crevices, hemorrhage and exudate. Fluorescence was noted in infected tracheas throughout both trials using fluorescent antibody (FA) technique.

Animals↗
PubMed1976

Cecal mucosal response to coccidiosis in growing chickens.

The cecal mucosal changes of a subclinical coccidial (E. tenella) in chickens was studied by scanning electron microscopy. Oral inoculation was used and the mucosal surface of the ceca was studied. A control group from the same hatch of chickens was sampled simultaneously. The ceca from the infected birds was markedly smaller and contained some hemorrhagic areas. The control birds maintained a relatively smooth continuous epithelium throughout the study. During the infection, early fenestration was seen in the epithelium followed by its disruption. The crypts were easily seen as the disease progressed and in some cases the epithelium became denuded. The infective organism may inhibit replacement of degenerating epithelium.

Animals↗
PubMed1976

Infected feather follicles in cage reared broilers.

A high incidence of feather follicle infection was observed in broilers reared in cages with wood slat floors. The incidence of feather follicle infection was significantly higher for males than for females within cage-reared broilers at 59 days of age. Male broilers at 50 days of age had a significantly lower incidence of the feather follicle condition than hatch mates at 59 days of age. Intact feather follicles were removed from freshly killed cage-reared birds and prepared for scanning electron microscopy (SEM). Examination of infected follicles revealed surface detail about the lesions. Removal of the encrustations covering the infected follicles revealed numerous cocci type bacteria at the base of the follicle. Infected and non-infected follicles were also examined by conventional histological techniques. Gram positive cocci were observed at the base of the infected follicles.

Animals↗
PubMed1975

Characteristics of the absorptive surface of the small intestine of the chicken from 1 day to 14 weeks of age.

The epithelial surface of the intertine of chicks 1 day to 14 weeks of age was examined with both scanning and transmission electron microscopes. Most of the intestinal villi were seen to be plate-like structures. During the first week post-hatch, goblet cell orifices were easily seen. Goblet cell pores were not readily apparent in the older birds. During this stage of early development discontinuity was seen among some epithelial cells. The villi of birds one week or older showed a more convoluted mucosal surface than the younger birds. Areas of cell extrusion were observed at the tips of some villi. The three dimensional cylindrical structure of the microvilli was shown with the scanning electron microscope.

Age Factors↗
PubMed1975

Scanning electron microscopy of the chicken crop--the avian rumen?

The mucosal surface of the chicken crop was examined with the scanning electron microscope. The proximal region in relation to the esophagus differed markedly from the distal region. The region nearest the esophagus showed a slightly folded surface with a very dense surface bacterial population while the region located in the apical region of the diverticulum was smoother with numerous sloughing cells and a sparse bacterial population. A potential for significant microbiological fermentation and digestion of feed in the crop is indicated.

Animals↗