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Biomedical subjects

J G Fox

Publications and source records attributed to J G Fox.

At least 253 records · Page 14Linked to original sources
PubMed1990

Effects of yohimbine on bradycardia and duration of recumbency in ketamine/xylazine anesthetized ferrets.

Eleven adult ferrets (Mustela putorius furo) were anesthetized with ketamine hydrochloride (25 mg/kg, IM) and xylazine hydrochloride (2 mg/kg, IM). Fifteen minutes post-ketamine/xylazine injection, ferrets were treated with yohimbine hydrochloride at a dose of 0.5 mg/kg, or an equal volume of physiologic saline, intramuscularly. Each ferret served as its own control by randomly receiving both treatments with a minimum interval of 2 weeks between treatments on any one ferret. At 15 minutes post-ketamine/xylazine injection, mean heart rate measurements for both treatment groups were 27% less than the mean heart rate measurement reported for unanesthetized ferrets. Intramuscular administration of yohimbine antagonized the ketamine/xylazine induced bradycardia in 10 of the 11 ferrets, (p = 0.0001). In yohimbine treated ferrets, an increase in mean heart rate measurement was noted 5 minutes after the intramuscular administration of yohimbine, and followed, over the next 15 minutes, by a progressive increase in mean heart rate. However, a corresponding decrease in mean heart rate measurement was observed in saline treated controls. Fifteen minutes after the injection of yohimbine, the mean heart rate measurement of yohimbine treated animals had increased to 194 beats per minute. This mean heart rate measurement is nearly 30% greater than the mean heart rate of 150 beats per minute measured at 15 minutes post-saline injection in saline treated controls. Also, yohimbine treatment significantly reduced duration of recumbency in 10 of 11 ferrets (p = 0.0001). Mean duration of recumbency for yohimbine treated ferrets was 41 +/- 9.7 minutes, whereas mean duration of recumbency for saline treated ferrets was determined to be 80 +/- 11.4 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Treatment of proliferative colitis in ferrets.

Proliferative colitis associated with intracellular Campylobacter sp was diagnosed in 10 ferrets. The ferrets had a history of diarrhea (often blood-tinged or mucoid), dehydration, and chronic weight loss. Additional clinical signs included rectal prolapse, lethargy, fever, and a palpably thick colon. In 5 ferrets, the diagnosis was confirmed by colonic biopsy, via endoscopy. Supportive treatment in 5 ferrets did not alleviate the clinical signs or the proliferative intestinal disorder. oral chloramphenicol treatment (50 mg/kg of body weight, q 12 h for 10 to 21 days) resulted in marked clinical improvement and eradication of proliferative intestinal lesions in 5 ferrets.

Animals↗
PubMed1989

Quantitation of methylated hemoglobin via hydrolysis of methyl esters to yield methanol.

Methyl esters formed by methylation of carboxylic acid groups on hemoglobin can be quantitated via GC/MS negative-ion chemical ionization analysis of the pentafluorobenzoate derivative of the methanol released from the hemoglobin upon base hydrolysis. Although the method requires extensive cleanup of extracting solvents because of the ubiquitous presence of trace levels of methanol, it is possible to quantitate adducted hemoglobin at levels as low as 4 ng per gram of hemoglobin using [13C, 2H3]methyl alcohol as the internal standard. In principle this method can be used in humans as a dosimeter for exposure to environmental methylating or alkylating agents.

Animals↗
PubMed1989

Dietary beta-carotene absorption and metabolism in ferrets and rats.

The ability of the ferret (Mustela putorius furo) to absorb dietary beta-carotene was studied to determine its appropriateness as a laboratory animal model for studies on beta-carotene metabolism. At baseline, the mean serum beta-carotene level in ferrets was 0.6 micrograms/dl and no beta-carotene was present in liver or adipose tissue. After the ferrets were fed 4 or 20 mg of beta-carotene/kg body wt daily for 2 wk, serum levels were 15.3 and 41.5 micrograms/dl, liver values were 0.9 and 4.1 micrograms/g and adipose tissue values were 0.1 and 0.2 microgram/g of beta-carotene, respectively. Thus, like humans, ferrets are able to absorb dietary beta-carotene intact. Further, these animals can store quantifiable amounts of dietary beta-carotene in their liver and, to a lesser extent, in adipose tissue. In contrast, serum beta-carotene levels in rats fed the two levels of beta-carotene were very low (0.5 to 0.6 microgram/dl) and no beta-carotene was found in liver or adipose tissue. Thus, the ferret is a more appropriate animal model for studying the intestinal absorption of beta-carotene and its storage and metabolism in body tissues.

Adipose Tissue↗
PubMed1989

Variability of the antigenicity of the glomerular basement membrane in nail-patella syndrome.

The difficulty of diagnosing Alport-type nephritis, and the possibility of altered antigenicity of the glomerular basement membrane in Alport-type nephritis is discussed. Attention is focused on the monoclonal antibody MCA-Pl as a specific tool in studying the Goodpasture antigenetic determinant in renal biopsy specimens. The clinical details and the results of MCA-Pl binding studies for three patients with nail patella syndrome are presented. Two of these patients proved to have an abnormal antigenicity of the glomerular basement membrane as demonstrated by the absence of binding of MCA-Pl. This is the first time that such an abnormality has been demonstrated in patients other than those with Alport-type nephritis. The significance of these results is discussed.

Adult↗
PubMed1989

"Campylobacter upsaliensis" isolated from cats as identified by DNA relatedness and biochemical features.

Campylobacter spp. were isolated from the feces of 20 (58%) of 53 asymptomatic cats during routine physical examination while the cats were maintained in an accredited quarantine facility. Fifteen of these Campylobacter spp. were identified phenotypically as Campylobacter jejuni, and two were identified as C. coli. DNA-DNA hybridization (hydroxyapatite method) was used to confirm the identification of three thermotolerant catalase-negative isolates. They were 80 to 100% related to each other and to the type strain of "C. upsaliensis" in reassociation reactions under optimal conditions and a stringent hybridization criterion. These strains were 75 to 100% interrelated and less than 12% related to type strains of other Campylobacter species. These strains represent the first reported feline isolate of "C. upsaliensis" and show that cats used in biomedical research can harbor this and other Campylobacter species.

Animals↗
PubMed1989

Investigation of zoonotically acquired Campylobacter jejuni enteritis with serotyping and restriction endonuclease DNA analysis.

Five strains of Campylobacter jejuni were isolated from asymptomatic coyotes being maintained in a vivarium. According to the results of serotyping with thermostable antigens and of bacterial chromosomal restriction endonuclease analysis, one of the C. jejuni strains isolated from the coyotes was responsible for enteritis in a laboratory animal technician providing husbandry for the laboratory-maintained coyotes.

Animals↗
PubMed1989

Methyl prednisolone acetate modulation of infection and subsequent pulmonary pathology in hamsters exposed to parainfluenza-1 virus (Sendai).

Parainfluenza-1 virus (PI-1) has a wide host range; the disease process observed varies with the age, previous exposure, and species. This study was performed to determine possible effects of the corticosteroid methyl prednisolone acetate (MPA) on PI-1 infection in hamsters. Hamsters serologically negative for PI-1 were exposed to virus alone or were exposed to virus the day after pretreatment with a single subcutaneous injection of MPA. Serum antibodies to PI-1 were present in virus-only exposed hamsters by Day 8 and increased up to Day 20. PI-1 was recovered from lungs of virus-only exposed hamsters on Day 2 to 8. Virus antigen was detected by immunocytochemistry on Days 2 to 10 in lungs of virus-only exposed hamsters. Virus-associated lesions in these hamsters began as acute bronchiolar epithelium degeneration and necrosis on Day 4 and were foci of fibrosis by Days 12 to 20. Hamsters exposed to virus after MPA treatment developed no antibodies to virus, had no virus detectable by plaque assays or immunocytochemistry, and had no pulmonary lesions. Hamsters treated with MPA had decreased total lymphocyte counts up to Day 20 after treatment. Treatment of hamsters with MPA one day prior to PI-1 virus exposure is associated with no detectable evidence of viral infection. Humoral and cellular immunity mediated by MPA-sensitive lymphocytes may mediate some of the manifestations of PI-1 pulmonary disease.

Animals↗
PubMed1989

Gastric campylobacter-like organisms: their role in gastric disease of laboratory animals.

Campylobacter pylori, first isolated in 1982, is now recognized as a primary cause of acute gastritis in man, and there is substantial data suggesting that this organism also plays an important role in the pathogenesis of duodenal ulcers. More recently, Campylobacter-like organisms and other morphologically distinct spiral bacteria have been isolated from gastric lesions in a variety of laboratory animal species. The zoonotic significance of C. pylori and other gastric spiral bacteria isolated from man as well as laboratory and domestic animals requires further study. An appreciation of the ecological and pathological role of gastric spiral bacteria in domestic and laboratory animals is an essential first step when considering the role and proper selection of animal models in the study of C. pylori gastroduodenal disease.

Animals↗
PubMed1989

Diversity of serotypes of Campylobacter jejuni and Campylobacter coli isolated in laboratory animals.

One hundred nineteen isolates of Campylobacter jejuni and Campylobacter coli from nine laboratory animal species were serotyped using antisera to 20 Penner serotypes commonly isolated from cases of human enteric infections. Although C. jejuni and C. coli were isolated from laboratory animals with diarrhea, the majority were cultured from asymptomatic animals (81%). Seven of twenty-two isolates from animals with diarrhea were serotype 4 (32%) and three were serotype 1 (14%). Sixty-one of the 119 isolates (51%) were typeable using the 20 Penner antisera indicating that many of the isolates obtained from 29 nonhuman primates (five species), 20 ferrets, 7 hamsters, 15 cats and 48 dogs are serotypes commonly associated with human enteritis. Among typeable strains, 13 different serotypes were identified. Two particular serotypes, 4 and 19 were isolated from several species of animals and comprised 24% of the isolates studied. Since asymptomatic laboratory animals of several different species harbor serotypes of C. jejuni and C. coli that are potentially pathogenic to man, appropriate precautions should be instituted to minimize exposure of personnel to the organisms in laboratory animal feces. If suspected cases of zoonotic-related enteric campylobacteriosis involving laboratory animals do occur, serotyping of isolates would be a useful epidemiologic marker in studying the outbreak.

Animals↗
PubMed1989

Campylobacter pylori-associated gastritis and immune response in a population at increased risk of gastric carcinoma.

A series of 169 consecutive patients from low socioeconomic strata attending the gastroenterology clinic of Charity Hospital in New Orleans were evaluated clinically and endoscopically. This general New Orleans population is known to be at increased risk of developing gastric carcinoma. The type of gastritis was identified histologically, and the presence of Campylobacter pylori was determined by culture and/or histology. The overall prevalence of C. pylori infection in this patient population was 71% (126/169). These findings were correlated with serum IgG antibody to C. pylori using an ELISA. Fifteen patients with neither demonstrable gastritis nor C. pylori served as negative controls and had low levels of IgG antibody to C. pylori. A strong correlation was found between Campylobacter detection by morphologic and/or culture technique and the presence of serum IgG antibody. For all patients examined, the sensitivity of the ELISA was 94.2% and the specificity 75.5%. The highest ELISA values for IgG antibody (sensitivity = 89%, specificity = 75%) were detected in patients positive for C. pylori, who also had diffuse antral gastritis with prominent lymphoid follicles. For patients with chronic atrophic gastritis and intestinal metaplasia, the sensitivity of the ELISA was 96% and the specificity 67%. The latter number may indicate underrepresentation of foveolar epithelium in biopsies with extreme intestinal metaplasia. Results suggest a high prevalence of chronic infection of C. pylori in this clinic population. The possible role of C. pylori in the development of precursor lesions of gastric cancer is discussed.

Adult↗
PubMed1988

A survey of renal function in outpatients with rheumatoid arthritis.

The acute renal side-effects of nonsteroidal anti-inflammatory drugs are well documented. These include interstitial nephritis, hyperkalaemia, renal tubular acidosis, fluid retention, hypertension and nephrotic syndrome. The long-term effects are less well known. We have carried out a cross-sectional survey of an unselected out-patient population with definite or classical rheumatoid arthritis to determine the prevalence of renal problems in this group. Thirty-four patients (20%) were shown to have an abnormality as defined by our criteria but in the majority this was transient or had been previously recognised. Thirteen patients (8%) had a persistent unexplained abnormality but only 1 had merited renal biopsy using established criteria (Patient 1). We conclude that the long-term use of NSAID's is associated with relatively few renal side-effects.

Adult↗