Biomedical subjects

S L Vonderfecht

Publications and source records attributed to S L Vonderfecht.

42 records · Page 3Linked to original sources

PubMed1983

Virus-specific immunity in neonatal and adult mouse rotavirus infection.

Mouse rotavirus (epizootic diarrhea of infant mice) was used as a model to study the role of virus-specific immunity in infection and diarrheal disease. The distribution of viral antigen in intestinal tissues was determined by immunofluorescent staining with anti-simian rotavirus (SA-11) serum. The location and proportion of antigen-positive cells appeared to vary as a function of time postinfection and age of the animal at the time of infection. In animals infected at 1 and 7 days of age, antigen-positive cells (5 to 25%) were first detected (1 day postinfection) in the proximal segment of the small intestine, and infection progressed to the middle and distal segments. At 10 days postinfection, virus-infected cells were no longer observed in the proximal segment. In animals infected at 21 days of age (disease-free), a significantly lower proportion of cells were antigen positive (2 to 5%), and they were restricted to the middle and distal segments of the small intestine. Infection, defined according to the presence of virus and viral antigens in intestinal tissues and by seroconversion in the immunoglobulin M (IgM) isotype as determined by enzyme-linked immunosorbent assay with SA-11 antigen, was observed for all age groups (neonatal to adult), even in the presence of virus-specific serum or intestinal immunoglobulins. On the other hand, diarrheal disease was not detected in neonatal mice (1 to 3 days old) positive for passively acquired virus-specific intestinal IgG. The presence of virus-specific IgA in the intestinal tract at the time of infection did not protect from subsequent diarrheal disease. Virus-specific, cell-mediated immunity, determined by a delayed-type hypersensitivity response, did not develop in neonatal mice infected at 5 and 12 days of age. Reinfection of adult mice was associated with suppression of virus-specific delayed-type hypersensitivity and a significant decrease in the titers of the virus-specific serum IgG and IgA.

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PubMed1983

Congenital intestinal aganglionosis in white foals.

A congenital and probably hereditary neurological defect has been identified in the intestinal tract of six foals produced from the breeding of overo (a type of spotting pattern) horses. The foals had white hair and pink skin with the exception of occasional pigmented foci about the muzzle, ventral abdomen, and hindquarters. The foals appeared normal at birth, but within a few hours developed symptoms of colic. At necropsy, the only significant finding was a narrow, pale segment of large intestine. This abnormality either was confined to the small colon and rectum or involved the entire colon and rectum. Microscopically, myenteric and submucosal neuronal plexuses were absent throughout the large intestine and extensive portions of the small intestine. The only other significant finding was the lack of melanin in the skin.

Animals↗

PubMed1982

Hemorrhagic streptococcal pneumonia in newly procured research dogs.

An acute necrotizing hemorrhagic pneumonia syndrome was recognized among 14 newly arrived research dogs. Typically, there were acute deaths without clinical signs. Necropsy revealed diffuse hemorrhagic pneumonia, and Lancefield group C Streptococcus zooepidemicus was isolated consistently from the lungs. In many cases, septic thrombi were seen in the small vessels of the kidneys, lymph nodes, spleen, brain, and adrenal glands. The syndrome was reproduced by intratracheal inoculation of the isolant into a susceptible dog.

Animals↗

PubMed1982

Immunity to rotavirus in conventional neonatal calves.

The local and systemic humoral immune responses to rotavirus were studied in six conventional neonatal calves. Attenuated bovine rotavirus was administered either orally or directly into an isolated intestinal loop. The parameters monitored were neutralizing rotavirus antibody in serum, immunofluorescent and neutralizing rotavirus antibody in intestinal loop washings, and rotavirus antibody-producing cells in intestinal mucosa. An antibody response was observed in the serum and intestinal secretions from one calf only. Viral replication was not detected in the isolated intestinal loop. Rotavirus antibody-producing cells were found in the intestinal mucosa of five calves. Double staining revealed that most of these cells produced antibody of the immunoglobulin A class. The conclusions were: (i) a previously described system to detect rotavirus antibody-producing cells can be used to study immune responses in neonatal calves, (ii) the class or subclass of antibody in rotavirus antibody-producing cells can be determined by double immunofluorescent staining, (iii) neonatal calves respond to rotavirus inoculation with a local immunoglobulin A response, and (iv) most of the rotavirus antibody-producing cells are located in the mucosa of the proximal small intestine.

Animals↗

PubMed1982

Detection of anti-rotavirus antibody-producing cells in paraffin-embedded tissue sections.

An assay to detect anti-rotavirus antibody-producing cells was developed in rabbits. Sections of alcohol-fixed, paraffin-embedded tissues were used to make an immunofluorescent "sandwich" consisting of specific antibody-producing cells, a concentrated suspension of bovine rotavirus, and rhodamine-conjugated anti-rotavirus serum. Rhodamine-stained, anti-rotavirus antibody-producing cells could be simultaneously stained by a fluorescein-conjugated antiserum reactive to rabbit immunoglobulin.

Animals↗

PubMed1980

A light and electron microscopic study of sarcocysts in a horse.

The structure of sarcocysts in a horse is presented. Light microscopic examination revealed that the maximum cyst dimensions were 136 X 990 micrometers and the cyst walls were striated and 1 to 3 micrometers thick. Electron microscopic examination revealed that the "cyst wall" was formed by villuslike protrusions of the parasitophorous vacuole's primary wall. A unique feature was the presence and arrangement of microtubules within the parasitophorous vacuole. Thirty-four to 55 microtubules extended from the apical tips and sides of each villus and passed through the ground matrix to form junctions with the outer pellicle membrane of bradyzoites and metrocytes located at the margins of the cyst. The average dimensions of the bradyzoites were 3.2 X 14.2 micrometers.

Animals↗