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Biomedical subjects

J G Fox

Publications and source records attributed to J G Fox.

At least 181 records · Page 10Linked to original sources
PubMed1994

Helicobacter pylori isolated from the domestic cat: public health implications.

Helicobacter pylori has been directly linked with active chronic gastritis, peptic ulceration, and gastric adenocarcinoma in humans. Although a substantial portion of the human population is colonized with H. pylori, the patterns of transmission of the organism remain in doubt, and reservoir hosts have not been identified. This study documents the isolation of H. pylori from domestic cats obtained from a commercial vendor. The isolation of H. pylori from these cats was confirmed by morphologic and biochemical evaluations, fatty acid analysis, and 16S rRNA sequence analysis. H. pylori was cultured from 6 cats and organisms compatible in appearance with H. pylori were observed in 15 additional cats by histologic examination. In most animals, H. pylori was present in close proximity to mucosal epithelial cells or in mucus layers of the glandular or surface epithelium. Microscopically, H. pylori-infected cat stomachs contained a mild to severe diffuse lymphoplasmacytic infiltrate with small numbers of neutrophils and eosinophils in the subglandular and gastric mucosae. Lymphoid follicles were also noted, particularly in the antrum, and often displaced glandular mucosal tissue. Thus, the domestic cat may be a potential model for H. pylori disease in humans. Also, the isolation of H. pylori from domestic cats raises the possibility that the organism may be a zoonotic pathogen, with transmission occurring from cats to humans.

Animals↗
PubMed1994

Animal and public health implications of gastric colonization of cats by Helicobacter-like organisms.

The bacterial genus Helicobacter contains a number of species which colonize the gastric mucosa of mammals. Natural and/or experimental gastric pathology has been correlated with colonization in humans and a wide variety of animal species. Historical reports in the literature suggest that a high percentage of cats are colonized by large, spiral, gastric helicobacter-like organisms (GHLOs). One of these bacteria (Helicobacter felis) has been isolated on artificial media and has experimentally caused gastritis in gnotobiotic dogs. This study surveyed the prevalence of helicobacter colonization in random-source cats by using the urease assay. Histologic examination was performed to determine the degree of associated pathology present. GHLOs associated with chronic gastritis were present in 70% of the juvenile and 97% of the adult cats studied. Although further study is needed to determine specifically what role GHLOs play in feline gastrointestinal disease, these results indicate that helicobacter colonization should be considered in the pathogenesis of feline gastroenteropathy. Furthermore, the high prevalence of feline infection is interesting because cats have recently been implicated as a potential reservoir for human infection by helicobacter-like organisms.

Animals↗
PubMed1994

Intracellular Campylobacter-like organism from ferrets and hamsters with proliferative bowel disease is a Desulfovibrio sp.

Proliferative bowel disease is an intestinal disorder of a variety of domestic animals associated with the presence of an intracellular Campylobacter-like organism (ICLO). We have identified the ICLO obtained from a ferret with proliferative colitis by 16S rRNA sequence analysis. In this ferret, proliferative bowel tissue containing the ICLO had translocated to the mesenteric lymph nodes, omentum, and liver. The 16S rRNA genes of the ICLO were amplified from an infected fragment of extraintestinal tissue by using universal prokaryotic primers. Approximately 1,480 bases of the amplified 16S rRNA gene were sequenced by cycle sequencing. Comparison of the sequence of the ICLO with those of over 400 bacteria in our data base indicated that the sequence of the ICLO was most closely related to that of Desulfovibrio desulfuricans (87.5% similarity). Phylogenetic analysis with 12 Desulfovibrio species and 20 species from related genera placed the ICLO in a subcluster within the genus Desulfovibrio with D. desulfuricans and 5 other Desulfovibrio species. We will refer to this organism as the intracellular Desulfovibrio organism (IDO). Specific primers were produced for PCR amplification of a 550-base fragment of the 16S rRNA gene of the IDO in proliferative intestinal tissue samples. This unique 550-base segment was amplified from samples of frozen intestinal tissue from nine ferrets and three hamsters with ICLO-associated disease but not in four intestinal tissue samples from animals without the ICLO-associated disease. The 550-base amplified products from the bowel tissues of one hamster and one ferret were fully sequenced. The ferret IDO partial sequence was identical to the previously determined 16S rRNA sequence over its length, and the hamster IDO sequence differed by a single base. The same intracellular organism has been identified in proliferative intestinal tissues of swine and that the organism has been successfully maintained in tissue culture. The availability of specific primers for PCR-based detection of this intracellular Desulfovibrio organism will aid in the determination of its role in the pathogenesis of proliferative bowel disease in a variety of infected hosts.

Animals↗
PubMed1994

Helicobacter hepaticus sp. nov., a microaerophilic bacterium isolated from livers and intestinal mucosal scrapings from mice.

A bacterium with a spiral shape and bipolar, single, sheathed flagella was isolated from the livers of mice with active, chronic hepatitis. The bacteria also colonized the cecal and colonic mucosae of mice. The bacterium grew at 37 degrees C under microaerophilic and anaerobic conditions, rapidly hydrolyzed urea, was catalase and oxidase positive, reduced nitrate to nitrite, and was resistant to cephalothin metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter hepaticus. This new helicobacter, like two other murine Helicobacter species, H. muridarum and "H. rappini," is an efficient colonizer of the gastrointestinal tract, but in addition, it has the pathogenic potential to elicit persistent hepatitis in mice.

Animals↗
PubMed1994

A technique for catheterization of the urinary bladder in the ferret.

The technique of catheterization of the urinary bladder, an important clinical skill for the diagnosis of urinary tract disorders, has not been described for the ferret. The bladder was catheterized in 23 ferrets (10 intact females; 11 spayed females; and 2 intact males) using a 3 1/2 French, red rubber urethral catheter fitted with a steel wire stylet. Ferrets were anaesthetized with isoflurane or ketamine (30 mg/kg IM) and xylazine (3 mg/kg IM). Females were positioned in ventral recumbency with the rear quarters elevated by a rolled surgical towel. The urethra was catheterized by direct visualization of the external urethral orifice using a vaginal speculum. The orifice was approximately 1 cm cranial to the clitoral fossa on the ventral floor of the vestibule. Blind passage was used in several spayed females. In males, the distal end of the penis was exteriorized from the prepuce and the external urethral orifice cannulated without stylet. No difficulty was encountered in advancing the catheter past the os penis. This catheterization technique allows urinary tract access for urine collection, pneumocystography, contrast cystography, double contrast cystography, and urine output determination in pharmacologic studies or in critical care of debilitated animals.

Anesthesia↗
PubMed1994

Gastric disease in ferrets: effects of Helicobacter mustelae, nitrosamines and reconstructive gastric surgery.

PURPOSE: Animal models are being used to study the mechanisms by which Helicobacter spp. induce gastric disease. To assess the effects of a natural gastric pathogen, Helicobacter mustelae, in the development of chronic gastritis, premalignancy and cancer, the ferret model was studied under natural and experimental conditions. ANIMALS AND METHODS: H. mustelae-infected ferrets were used to study the metabolism of nitrates/nitrites, which are dietary and endogenously formed substances that have been linked to gastric cancer. The ferret was also manipulated by performing gastric reconstructive surgery to study the processing of nitrite and nitrate and to assess the effect of surgery on gastric pathology. In addition, the ferret was tested for its suitability as an animal model for the induction of gastric cancer by oral dosing with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The influence of these variables on gastric pathology and/or metabolic outcomes was examined, and the results in ferrets were compared to findings in humans. RESULTS AND CONCLUSIONS: The ferret appears to be an ideal model for studying various gastric parameters and how these factors influence the development of H. mustelae-associated gastric disease. Gastric reconstructive surgery did not effect nitrite processing or overall severity of gastritis in ferrets. However, a single dose of MNNG (50 mg/kg) produced an unprecedented 90% gastric carcinoma in H. mustelae-infected ferrets. This implies that chronic inflammation induced by the bacterium is a cofactor in gastric carcinogenesis.

Adenocarcinoma↗
PubMed1994

Effect of isoflurane on hematologic variables in ferrets.

Effects of isoflurane on the CBC in ferrets were studied. There was rapid decrease in all hematologic variables after induction of anesthesia. Percentage reductions in indices of the erythron (hematocrit, RBC count, hemoglobin concentration) exceeded those of plasma protein concentration and WBC count at the first postinduction time point. There was little additional decrease in these variables for the duration of anesthesia. The values had partially recovered to preanesthetic baseline at 45 minutes after anesthesia. Although these alterations appear to be well tolerated in healthy ferrets, care should be exercised when subjecting anemic, geriatric, or debilitated ferrets to isoflurane-induced anesthesia.

Animals↗
PubMed1994

Enterocecocolitis associated with Escherichia coli and Campylobacter-like organisms in a hamster (Mesocricetus auratus) colony.

Sporadic diarrhea and weight loss were observed in a breeding colony of Syrian hamsters during a 2-year period. Thirteen adult hamsters with diarrhea, anorexia, and weight loss were examined. Histologic lesions consisted of diffuse nonsuppurative enterocecocolitis and multifocal epithelial proliferation in the cecum and colon. Goblet cell hyperplasia was extensive in the colonic mucosa of many hamsters. The hamsters in this colony had not been treated with antibiotics nor was Clostridium difficile isolated from any of the hamsters. In contrast to typical proliferative ileitis in hamsters, most hamsters involved in this outbreak were mature adults rather than weanlings, and lesions were predominantly inflammatory rather than proliferative and involved small intestine, cecum, and colon rather than ileum. The isolation of beta-hemolytic Escherichia coli and demonstration of Campylobacter-like organisms by transmission electron microscopy and Warthin-Starry staining suggest that these two agents were involved in the pathogenesis of this disease. Further studies, however, are needed to investigate the pathogenesis of this enteric syndrome in hamsters.

Animals↗
PubMed1994

Prolactin-secreting pituitary adenomas with mammary dysplasia in New Zealand white rabbits.

Nine aged (mean age = 3.2 years) nulliparous New Zealand white rabbit does were found to have markedly enlarged teats. The teats were frequently engorged with fluid but were not hot and did not cause signs of pain. The number of affected teats per animal ranged from 1 to 8 (mean = 4). The teats and associated glandular tissue were typically discolored grey, blue, or greenish black (n = 6). Prolactin concentrations were evaluated by radioimmunoassay. Serum prolactin concentrations ranged from 22.4 ng/ml to 2.21 micrograms/ml (mean = 397.3 ng/ml), which was 10- to 1000-fold greater than normal values in nonpregnant rabbits. Conventional radiography of the skull of six rabbits did not reveal pituitary enlargement. Necropsy revealed an enlarged pituitary gland and sella turcica in six of nine does. The diaphragma sellae had ruptured in two rabbits. All nine rabbits had pituitary acidophil adenomas. The neoplastic portions of the pituitaries were diffusely immunoreactive when stained immunohistochemically for prolactin. In contrast, only small clusters of five to seven cells stained positively in normal pituitaries selected as controls. Histologic examination of the mammary glands revealed numerous large dilated cystic spaces containing proteinaceous fluid. Many cysts had numerous papillary epithelial infoldings. The cystic dilations extended into and included the teat canal producing the gross appearance. Prolactin-secreting acidophil adenomas have not been previously reported in the rabbit, and the association with mammary dysplasia is unique.

Adenoma, Acidophil↗
PubMed1994

Estimation of glomerular filtration rate and evaluation of renal function in ferrets (Mustela putorius furo).

Three methods of determining glomerular filtration rate (GFR) were performed in adult ferrets, 9 months to 7 years old. Endogenous creatinine clearance was determined, using serum and urine creatinine values obtained during 24- and 48-hour collection periods from 27 ferrets housed in metabolic cages. Creatinine and radiolabeled inulin were administered to 12 female ferrets by constant IV infusion during isoflurane-induced anesthesia. Serial 20-minute urine collections, together with serum samples obtained at the midpoint of urine collection, provided measures for clearance calculations of these substances. Mean +/- SD endogenous creatinine clearance in ferrets for metabolic cage collections was 2.50 +/- 0.93 ml/min/kg of body weight. There were no significant differences between the 24- and 48-hour clearance rates. Mean inulin clearance was 3.02 +/- 1.78, and mean exogenous creatinine clearance was 3.32 +/- 2.16 ml/min/kg. Analysis of variance, using least-squared means adjustment, did not yield any significant differences between inulin and exogenous creatinine clearance rates. Exogenous creatinine clearance-to-inulin clearance ratio was 0.99 +/- 0.46, and there was significant correlation between the 2 methods (r = 0.82, P = 0.0001). Significant body temperature effects on inulin or exogenous creatinine clearance were not found. Infused inulin clearance, the generally preferred method for GFR calculation in mammalian species, was significantly (P = 0.0069) higher in younger (3.65 ml/min/kg) vs older ferrets (2.29 ml/min/kg). Results of this study indicate that inulin clearance is an adequate measure of GFR in ferrets as it is in other species. Compared with inulin clearance, exogenous creatinine clearance also provides a reliable estimate of GFR in ferrets.

Aging↗
PubMed1994

The relationship between urinary albumin excretion rate and serum cholesterol in primary glomerular disease.

The relationship between urinary albumin excretion rate (AER) and serum cholesterol was investigated in a group of 100 patients with primary glomerular disease. Patients were classified into four groups according to AER: 1. normal < 30 mg/24 h; 2. microalbuminuria 30-300 mg/24 h; 3. proteinuria 300-3000 mg/24 h; 4. nephrotic > 3000 mg/24 h. Serum cholesterol values for each patient were compared with the mean of two healthy controls matched for age, sex and weight. Although the albuminuric group had significantly increased serum cholesterol concentrations compared to controls (6.58 mmol/l sd 1.81 v. 5.91 sd 0.88; paired t, p < 0.003), this was almost entirely explained by the increase in the group with AER > 3000 mg/24 h (8.47 mmol/l sd 2.43 v. 6.18 sd 0.61; paired t, p < 0.02). However, there was a relationship between the log transformed values for serum cholesterol and AER which persisted even when those with AER > 3000 mg/day were excluded. These data suggest that albuminuria less than the nephrotic range has a minor influence on serum cholesterol in patients with primary glomerular disease.

Albuminuria↗
PubMed1993

Estradiol-17 beta-secreting adrenocortical tumor in a ferret.

Severe generalized alopecia and marked vulvar enlargement were observed in a 5-year-old spayed ferret with high serum estradiol concentrations. A neoplastic left adrenal gland was removed. Staining of the neoplastic cells for estradiol was demonstrated by use of immunohistochemistry. Clinical findings in this ferret were typical of adrenal-associated endocrinopathy, a syndrome characterized by increased secretion of adrenocortical hormones by hyperplastic or neoplastic adrenal glands.

Adrenal Cortex Neoplasms↗
PubMed1993

Intestinal perfusion of beta-carotene in the ferret raises retinoic acid level in portal blood.

To determine whether beta-carotene (beta-C) can serve as a source of intestinally-derived retinoic acid (RA), either 15,15'-[14C]beta-C or unlabeled beta-C was perfused through 30 cm jejunal segments of ferrets in vivo. Portal vein blood was sampled periodically via an indwelling catheter. RA was identified in portal blood by comparing retention times in HPLC, by UV absorption, and by derivatization (methylation) and subsequent GC-MS analysis. The RA concentration in the portal blood increased 3-fold with perfusion of beta-C (P < 0.05), and remained at 18 nmol/L during the perfusion of beta-C. The single peak of RA in HPLC was shown to consist of four separate peaks by GC-MS, which may be cis-trans isomers of RA. The concentration of RA in portal blood returned to the initial level (5 nmol/L) after a 2 h period of intestinal perfusion with 5% dextrose. Retinyl ester concentration in portal blood did not change before or after the perfusion, whereas retinol decreased significantly during the perfusion of beta-C. This study clearly indicates that a considerable quantity and number of polar metabolites, including RA, are formed from beta-C in the ferret intestine which are transported via the portal vein to the liver.

Animals↗
PubMed1993

Functional islet cell tumor in six ferrets.

Functional islet cell tumor was diagnosed in 6 ferrets. Prominent clinical signs included weight loss, hind limb weakness, ptyalism, and tremors. The diagnosis was made on the basis of 2 or more of the following methods and confirmed by histologic examination of biopsied tissue: hypoglycemia on routine serum biochemical analysis, clinical signs of hypoglycemia, simultaneous development of hypoglycemia (44 +/- 9.9 mg/dl; mean +/- SD), and hyperinsulinemia (58 +/- 18.4 microU/ml; mean +/- SD) after food was withheld for 4 hours. Surgical resection of affected tissue was associated with clinical improvement in all cases. Foci of metastasis were found in 1 ferret. Diazoxide was unsuccessful in controlling persistent postsurgical hypoglycemia in 2 ferrets. Additional functional islet cell tumors were identified in 5 of 6 ferrets at necropsy. Functional islet cell tumors are important neoplasms of older ferrets. Preventive health programs for ferrets > 3 years old should include monthly weight determinations and biannual CBC and serum biochemical analysis.

Adenoma, Islet Cell↗
PubMed1993

The spectrum of disease associated with a positive ANCA.

This is a retrospective analysis of all patients with a raised titre of ANCA in a single centre over a two-year period. Sixty-five patients were identified and clinical data is presented for 58 of these-34 male and 24 female. The median age is 56 years (13-83). Fourteen patients had Wegener's granulomatosis, 14 microscopic polyarteritis nodosa and 30 had other diagnoses. The patients with unexpectedly positive results are discussed in detail. This study confirms the sensitivity of ANCA in Wegener's granulomatosis and microscopic polyarteritis nodosa but suggests that the test is not as specific as initially claimed.

Adult↗