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Biomedical subjects

J G Fox

Publications and source records attributed to J G Fox.

At least 199 records · Page 11Linked to original sources
PubMed1993

Role of gastric pH in isolation of Helicobacter mustelae from the feces of ferrets.

BACKGROUND: Helicobacter mustelae colonizes the gastric mucosa of ferrets and causes persistent chronic gastritis. METHODS: Hypochlorhydria, as measured by gastric pH probe, was induced by administering oral omeprazole, a proton pump inhibitor of the parietal cell, to adult ferrets in two separate experiments. Feces of ferrets were cultured for H. mustelae before, during, and after omeprazole therapy. RESULTS: H. mustelae was isolated in 23 of 55 (41.8%) sequential fecal samples collected during omeprazole therapy. The same ferrets with acidic gastric pH had H. mustelae isolated in 6 of 62 (9.7%) of the fecal cultures (P < 0.01). A DNA species-specific H. mustelae probe confirmed the presence of the organism in both the stomach and feces of all 5 ferrets. In 4 of 5 ferrets restriction enzyme patterns of the gastric H. mustelae were identical to those of the fecal H. mustelae strains. CONCLUSIONS: Hypochlorhydria promotes fecal transmission of a gastric Helicobacter organism. The H. mustelae-colonized ferret provides an ideal model to study the epidemiology and pathogenesis of Helicobacter pylori-induced gastritis.

Animals↗
PubMed1993

Assessment of glomerular charge selectivity in man by differential clearance of isoamylases.

1. Glomerular charge selectivity was assessed using the ratio of the clearance of pancreatic isoamylase to the clearance of the more anionic salivary isoamylase (CPAm/CSAm) in 30 normal subjects, 14 patients with minimal proteinuria and 23 patients with heavy proteinuria due to primary glomerulopathies. Seven patients with minimal change nephropathy were studied in relapse and remission. 2. CPAm/CSAm exceeded 2.0 (range 2.1-6.1) in all normal subjects, indicating that the normal glomerular capillary wall possesses charge selectivity at the molecular size of amylase (molecular mass 56 kDa). 3. CPAm/CSAm was significantly lower in patients with heavy proteinuria than in normal subjects or patients with minimal proteinuria. CPAm/CSAm was low in patients with minimal change nephropathy in relapse and rose into the normal range with steroid-induced remission. 4. These data suggest that heavy proteinuria in primary glomerulopathies is accompanied by loss of glomerular charge selectivity. Remission of minimal change nephropathy is associated with restoration of normal charge selectivity.

Adult↗
PubMed1993

MNNG-induced gastric carcinoma in ferrets infected with Helicobacter mustelae.

N-Methyl-N-nitro-N'-nitrosoguanidine (MNNG) is a gastric carcinogen in several animal species and has been used in a number of systems to dissect the co-carcinogenic potential of various compounds in the induction of gastric adenocarcinoma. Recent epidemiological evidence suggests that Helicobacter pylori may play a role as a co-carcinogen in the etiology of this tumor in humans and we have been interested in developing an animal model to study this possibility. A related organism, H. mustelae, naturally colonizes the ferret stomach and causes persistent chronic gastritis. The pathology elicited by H. mustelae in ferrets has many similarities with the human disease including different stages of multifocal atrophic gastritis which underlie the gastric ulcer and gastric carcinoma syndrome. There is little evidence, however, demonstrating the susceptibility of ferrets toward chemical carcinogenesis. We have consequently undertaken a study to ascertain whether 10 6-month-old female ferrets given a single oral dose of MNNG (50-100 mg/kg) would develop adenocarcinoma of the stomach. Five age-matched unmanipulated control animals were included for comparative purposes. All 15 ferrets were infected with H. mustelae. Nine of 10 ferrets dosed with MNNG developed gastric adenocarcinoma (29-55 months after dosing), while none of the five historical control ferrets examined an average of 63 months after the initiation of the study developed gastric tumors. By comparison, we have not observed gastric adenocarcinoma, nor has it been reported, in > 10 years of observation of untreated ferrets naturally infected with H. mustelae. The H. mustelae-infected ferret, with demonstrated susceptibility to a gastric carcinogen, plus the recent availability of specific pathogen-free ferrets, should now allow longitudinal studies in vivo to probe the role of Helicobacter in the development of gastric cancer.

Adenocarcinoma↗
PubMed1993

Comparison of the major outer-membrane protein (MOMP) gene of mouse pneumonitis (MoPn) and hamster SFPD strains of Chlamydia trachomatis with other Chlamydia strains.

Restriction fragments containing the major outer-membrane protein (MOMP) gene from two nonhuman (rodent) strains of Chlamydia trachomatis, the mouse pneumonitis (MoPn) strain and the SFPD strain isolated from hamsters with transmissible proliferative ileitis, were cloned and sequenced. The MOMP genes of both MoPn and SFPD encode an identical 22-amino acid leader peptide and mature polypeptides of 365 and 382 amino acids, respectively. Alignment of the MOMP genes of the two rodent strains revealed 91% identity. By comparison with other known chlamydial MOMP gene sequences, there was 80%-83% identity with human biovars strains of C. trachomatis, and there was 69%-70% identity with C. psittaci and C. pneumoniae strains. The main differences in these sequences were clustered into four variable domains. A minimum-length evolutionary tree was constructed on the basis of the MOMP gene variable positions by using PIMA package software. The minimum mutation distances indicated that (i) the MOMP genes of all chlamydial strains may have evolved from a common ancestor; (ii) all the strains of C. trachomatis compose one of the subtrees, and strains of C. psittaci and C. pneumoniae compose the other subtree; and (iii) in the C. trachomatis subtree, the human and the rodent strains are divided into two clusters. The branching pattern of this evolutionary tree is generally consistent with current classification based on serological, morphological, and other biological characteristics.

Amino Acid Sequence↗
PubMed1993

Helicobacter acinonyx sp. nov., isolated from cheetahs with gastritis.

Four strains of a novel Helicobacter species were isolated from the stomachs of cheetahs (Acinonyx jubilatus) with gastritis. These isolates were phenotypically similar to Helicobacter pylori. The isolates were gram-negative, spiral bacteria which grew under microaerophilic conditions at 37 degrees C, but not at 25 or 42 degrees C, and produced urease, catalase, oxidase, alkaline phosphatase, and gamma-glutamyl transpeptidase. The isolates did not ferment glucose, mannitol, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin, or arabinose; hydrolyze hippurate or indoxyl acetate; or reduce nitrate. They did not produce H2S from triple sugar iron agar, and they did not grow in the presence of 1.0% glycine or 1.5% NaCl. They were resistant to nalidixic acid and sensitive to cephalothin and metronidazole. Cells were typically 0.3 by 2.0 microns and possessed tufts of two to five sheathed, monopolar flagella. The G+C content of strain 90-119 was 30 mol%. Cluster analysis of densitometry scans of polyacrylamide protein gels revealed more than 70% similarity of the cheetah isolates to H. pylori, less than 60% similarity to Helicobacter felis, and less than 50% similarity to Helicobacter mustelae. Complete 16S rRNA sequences were determined for two of the cheetah isolates. Phylogenetic analysis was performed by comparing the cheetah sequences to those of 19 reference strains, including H. pylori, H. felis (two strains), H. mustelae, Helicobacter muridarum, "Flexispira rappini," Wolinella succinogenes, Campylobacter coli, Campylobacter concisus, Campylobacter curvus, Campylobacter fetus, Campylobacter hyointestinalis, Campylobacter jejuni, Campylobacter lari, Campylobacter rectus, Campylobacter sputorum subsp. bubulus, a Campylobacter sp. (pig isolate), [Bacteroides] gracilis, and [Bacteroides] ureolyticus.(ABSTRACT TRUNCATED AT 250 WORDS)

Acinonyx↗
PubMed1993

Management of acute bleeding gastric malignancy.

Gastric malignancy was the cause of bleeding in 35 of a consecutive series of 2260 cases (1.5%) treated with upper gastrointestinal haemorrhage. Fifteen patients came to emergency surgery (43%). In 13 of 30 early endoscopies performed the lesion was thought to be benign (43%) and seven of these cases came to emergency surgery. Two patients died after 15 emergency operations (13%) compared with 15 deaths after 109 emergency operations (14%) for benign gastric ulcer during the same period of study. A total of four patients with malignant ulceration died after surgery in 33 cases (12%), two after 15 emergency operations and two after 18 elective procedures. The only significant predictors of urgent surgery for malignant ulcer were shock on admission and active bleeding or visible vessel on endoscopy. Resection of gastric malignancy was performed in 29 patients during initial admission and in four cases at a subsequent admission giving a final resection rate of 91%. Of the 28 patients with adenocarcinoma, 19 had localized disease (Stage I or II) (68%). Nine patients were treated by total gastrectomy, five at an initial elective procedure and four at a second procedure.

Acute Disease↗
PubMed1993

Local and systemic immune responses in murine Helicobacter felis active chronic gastritis.

Helicobacter felis inoculated per os into germfree mice and their conventional non-germfree counterparts caused a persistent chronic gastritis of approximately 1 year in duration. Mononuclear leukocytes were the predominant inflammatory cell throughout the study, although polymorphonuclear cell infiltrates were detected as well. Immunohistochemical analyses of gastric mucosa from H. felis-infected mice revealed the presence of mucosal B220+ cells coalescing into lymphoid follicles surrounded by aggregates of Thy-1.2+ T cells; CD4+, CD5+, and alpha beta T cells predominated in organized gastric mucosal and submucosal lymphoid tissue, and CD11b+ cells occurred frequently in the mucosa. Follicular B cells comprised immunoglobulin M+ (IgM+) and IgA+ cells. Numerous IgA-producing B cells were present in the gastric glands, the lamina propria, and gastric epithelium. Infected animals developed anti-H. felis serum IgM antibody responses up to 8 weeks postinfection and significant levels of IgG anti-H. felis antibody in serum, which remained elevated throughout the 50-week course of the study.

Animals↗
PubMed1993

Epizootic gastritis associated with gastric spiral bacilli in cheetahs (Acinonyx jubatus).

An outbreak of vomiting in a group of captive cheetahs (Acinonyx jubatus) was investigated, and histologic examination revealed chronic gastritis characterized by infiltration of lymphocytes and numerous plasma cells and epithelial erosions. Lymphoid follicles, globule leukocytes, scattered neutrophils, and (in one animal) abscessed gastric glands were inconsistent findings. In addition, necropsy of three cheetahs revealed gastric mucosal hyperplasia. Two kinds of bacteria were identified in the stomachs of infected cheetahs. Numerous long, tightly coiled motile Gastrospirillum-like organisms were seen in gastric mucus and in Warthin-Starry-stained sections of mucosa. These bacteria could not be cultured but were transmitted to conventional mice in homogenates of gastric mucosa from infected cheetahs. Ultrastructural examination revealed helical filaments on some of these bacteria. In addition, a smaller Helicobacter sp. was isolated. This organism could be cultured in vitro under microaerophilic conditions. One or both of these bacterial species was probably responsible for the gastritis in these cheetahs.

Acinonyx↗
PubMed1993

Practical venipuncture techniques for the ferret.

As the number of ferrets (Mustela putorius furo) used in research and kept as pets continues to rise, so does the need for simple, humane research and diagnostic techniques. We have developed venipuncture methods for the ferret utilizing the jugular and cephalic veins. Using these methods it is possible to repeatedly sample moderate volumes of blood and to perform intravenous injections in both conscious and sedated ferrets.

Animals↗
PubMed1993

Antigenic specificity and morphologic characteristics of Chlamydia trachomatis, strain SFPD, isolated from hamsters with proliferative ileitis.

Profound diarrhea associated with proliferating intestinal cells containing intraepithelial campylobacter-like organisms (ICLO) occurs in a variety of mammalian hosts, particularly swine and hamsters. Recently, intracellular bacteria were isolated from proliferative intestinal tissue of hamsters and propagated in intestine cell line 407. Oral inoculation of hamsters with cell culture lysates containing these organisms reproduced the disease in susceptible hamsters. In the present study, an intracellular bacterium from the INT 407 cell line was shown by a variety of techniques to be a member of the genus Chlamydia and has been designated Chlamydia sp. strain SFPD. McCoy cells infected with Chlamydia sp. strain SFPD demonstrated bright fluorescent-stained intracytoplasmic inclusions when examined with fluorescein-labeled species-specific C. trachomatis monoclonal antibodies. The organism also reacted to fluorescein-labeled polyclonal but not monoclonal ICLO "omega" antisera. Ultrastructural examination of the Chlamydia sp. strain SFPD from McCoy cells revealed electrondense elementary bodies and a less electron-dense reticulate-like body that was circular; both features are consistent in morphology to developmental forms of Chlamydia and do not conform to ICLO morphology. Molecular studies, 16S ribosomal sequence analysis, and sequencing of the outer membrane protein confirmed that the isolate is a C. trachomatis closely related to the mouse pneumonitis strain of C. trachomatis.

Animals↗
PubMed1993

Efficacy of tribromoethanol anesthesia in mice.

We undertook a retrospective study to evaluate the efficacy, safety, and suitability of tribromoethanol (0.2 ml/10 g body weight of a 1.2% solution) as a surgical anesthetic in mice. We compiled records of embryo transfer during a 2.5-year period (1989-1991) and examined mice subjected to several other procedures requiring anesthesia. We documented a low rate of mortality and morbidity (< 1%) and the absence of any significant abdominal adhesions or inflammatory response. The rapid induction and recovery, adequate surgical plane of anesthesia, and lack of complications make this anesthetic effective and simple to use. Precautions necessary to prevent decomposition of the anesthetic, storage in the dark at 4 degrees C, were minimal.

Anesthesia↗
PubMed1993

Audit of a decade of continuous ambulatory peritoneal dialysis.

We have reviewed the results of continuous ambulatory peritoneal dialysis (CAPD) in a single renal unit over the period from December 1979 to the end of 1990. Case records of 211 of the 222 patients treated by CAPD over this period were obtained and age, sex, diagnoses, duration of CAPD, and cause of death determined. We found marked effects of age and a diagnosis of atheromatous vascular disease at the start of CAPD on patient survival. For patients aged under 45 years 5-year patient survival was 78%, for those aged 45-65 it was 29% and for those aged over 65 years it was 32%. Patients with a diagnosis of atheromatous vascular disease at the start of CAPD had a 3-year survival of 25% compared with 69% for age- and sex-matched CAPD patients without such a diagnosis. Five-year technique survival was 67% if failure was defined as transfer to haemodialysis or death as a direct result of CAPD, but only 11% of patients were on CAPD continuously for 5 years. Attempts to compare our results with those from other reports were hindered by the variety of methods used to calculate patient and technique survival; we suggest that standard methods should be agreed.

Age Factors↗
PubMed1992

Parvovirus-associated syndrome (Aleutian disease) in two ferrets.

There is a paucity of information regarding natural Aleutian disease, caused by a parvovirus in ferrets. With the increasing popularity of ferrets as household pets and laboratory animals, and with the advent of a USDA-approved rabies vaccine, the occurrence and the etiopathogenesis of naturally acquired diseases in ferrets needs to be documented. We present the clinical and laboratory findings associated with Aleutian disease in 2 domestic ferrets, one with the chronic wasting form of the disease and one with the central nervous system form.

Aleutian Mink Disease↗
PubMed1992

Malignant lymphoma in ferrets: clinical and pathological findings in 19 cases.

The clinical and pathological findings in 19 ferrets (Mustela putorius furo) with malignant lymphoma are reviewed. Peripubescent ferrets had rapidly progressive stage IV high grade immunoblastic or small non-cleaved cell lymphoma. Adult ferrets had stage II or IV low grade diffuse small lymphocytic (DSL) lymphoma, stage IV high grade small non-cleaved cell lymphoma, or stage IV high grade immunoblastic polymorphous (IBP) lymphoma. Three ferrets had concurrent IBP and DSL lymphoma involving different organs. The IBP admixture of immunoblasts, large atypical lymphocytes, Reed-Sternberg-like cells, lymphoblasts and small lymphocytes has been associated with certain retrovirally associated lymphomas and nodal hyperplasias in man, non-human primates and cats. Aleutian disease, a parvovirus-induced lymphoproliferative disease, also involves clinical and histological features similar to certain lymphomas in ferrets. Seven ferrets tested were seronegative for feline leukaemia virus antigen. Only one of eight ferrets was positive for Aleutian parvovirus antibody. The clinical and pathological findings are suggestive of a viral aetiology for certain lymphomas in ferrets.

Animals↗
PubMed1992

Beta-carotene, retinol and retinyl ester concentrations in serum and selected tissues of ferrets fed beta-carotene.

The concentrations of beta-carotene, retinol and retinyl esters in serum and selected tissues of ferrets fed diets supplemented with beta-carotene (80 micrograms/g wet diet) for 3 wk were determined. The initial concentration of serum beta-carotene was 0.011 +/- 0.006 mumol/L (mean +/- SEM); at the end of the experimental period it was 5.75 +/- 1.60 mumol/L. No significant differences in serum retinol and total retinyl esters were observed between beta-carotene-fed and control ferrets that had been fed an unsupplemented diet. The predominant retinyl esters in serum were retinyl stearate (53%) and retinyl palmitate (35%). Of the tissues analyzed after beta-carotene feeding, the liver contained the highest concentration of beta-carotene (78.8 +/- 18.8 nmol/g). Other tissues that contained beta-carotene in amounts ranging from 17 to 20 nmol/g were adrenals, small intestine, stomach and colon; lesser amounts (6.9 nmol/g) were found in kidneys. Amounts ranging from 1.2 to 2.3 nmol/g were found in muscle, bladder, adipose tissue, lungs and skin; only 0.37 and 0.34 nmol/g were present in brain and eyes, respectively. Thus, like humans, ferrets have the capacity to absorb intact beta-carotene and to store this compound in tissues, especially the liver. However, compared with humans, ferrets have elevated concentrations of retinyl esters in serum, liver and other tissues.

Absorption↗