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C J Pfeiffer

Publications and source records attributed to C J Pfeiffer.

12 recordsLinked to original sources
PubMed1992

Reduction of papilloma size by ultraviolet irradiation in the Japanese newt, Cynops pyrrhogaster.

Experiments were conducted on 44 captive Japanese newts (Cynops pyrrhogaster) to test the hypothesis that ultraviolet (UV) irradiation might inhibit growth or induce regression of spontaneous skin papillomas of probable viral origin. An empirically derived exposure to UV irradiation (42 microW per cm2 per day) induced reduction of papilloma size which began approximately 4 weeks after irradiation was initiated. This regression included histological evidence of tissue vacuolization and cellular necrosis of papillomatous epithelium. These findings, taken together with previous data on seasonal, temperature and geographical influences on papilloma prevalence, lend support to the notion that solar UV radiation may modulate papilloma prevalence in the natural environment, possibly by direct effects on viral infection.

Animals↗
PubMed1992

A review of spontaneous ulcer disease in domestic animals: chickens, cattle, horses, and swine.

The human species is perhaps unique for its high incidence of spontaneous, chronic ulcer of the glandular mucosa of the stomach and duodenum. Nevertheless, spontaneous ulcers, usually of the stomach, commonly occur in many domestic animals. Some of these lesions are chronic and they may occur in either the glandular or squamous-lined regions of the stomach. As with the human disease(s) the pathogenesis in domestic animals is multifactorial, poorly understood, and variable between and within species. Some parallelisms exist in aggressive and defensive factors, but parasitic factors, via gastrinemia, and a histaminic factor via diet may occur in some animal ulcers. Underlying environmental stresses, of debated importance with the human disease but of proven importance in several rat ulcer models, may play a key role in some spontaneous gastric ulcer situations in swine and cattle. This is manifest in crowding and transporting situations. Seasonal, age, and weaning factors also alter the incidence of ulcer in cattle. Psychologic/environmental stress-related factors, as well as drug and physiologic stress factors appear to upset the balance in the horse between resistance and aggressive mucosal factors. Dietary factors which are highly important in ulcer disease in swine and chickens, have not yet been incriminated in spontaneous, equine ulcer disease. More investigation of the pathogenesis of domestic animal ulcers will prove useful for both human and veterinary medicine in terms of a) elucidating pathogenetic mechanisms for all species, b) may provide new animal models for study, and c) may enhance prevention of such lesions in domestic animals for economic and humanitarian reasons.

Animals↗
PubMed1992

Ethanol and the antioxidant defense in the gastrointestinal tract.

Ethanol is known to have profound actions on the gastrointestinal tract. The present study was undertaken to examine the effects of ethanol on some of the natural antioxidant defensive enzymes in the gastrointestinal tract; the activities of these enzymes in the liver and the brain were also measured for comparison with those in the gastrointestinal tract. Oral administration of absolute ethanol induced severe gastric mucosal lesions and also damage in the small intestine, however the total superoxide dismutase was unaffected in the tissues measured. The glucose-6-phosphate dehydrogenase activity was reduced only in the stomach while the total glutathione was elevated in the small intestinal mucosa. The catalase activities were activated in the stomach, small and large intestines, and brain, but not in the liver which contained the highest concentration of the enzyme. The present findings indicate that endogenous hydrogen peroxide may be an important damaging agent towards biomolecules in different organs and the removal of this by catalase represents an important defensive mechanism against ethanol toxicity.

Animals↗
PubMed1992

Ultrastructure of Brunner's glands in the horse.

Investigation of the duodenal submucosal glands of Brunner in the horse for the first time at the ultrastructural level has clarified some of the unique features of these equine glands. The horse is one of the very few mammals in which Brunner's glands are comprised of both mucous and serous tubuloacinar glands. Although the ultrastructural differences between the serous and mucous cell types are marked, particularly with respect to secretory granules and rough endoplasmic reticula, these cell types closely correspond to serous and mucous cells in the upper digestive system of other mammals. A minor and distinct population of goblet cell-like mucous cells, and endocrine-like cells were also observed in equine Brunner's glands. Both the serous and mucous cells appear to empty into common ducts which enter the base of the duodenal crypts. These submicroscopic cytologic data taken together with other physiologic data would suggest that, in the horse, Brunner's glands function both to provide mucosal protection in the proximal duodenum as well as to release digestive enzymes, such as lipase or other unidentified materials.

Animals↗
PubMed1979

Spontaneous regressive epitheliomas in the Japanese newt, Cynops pyrrhogaster.

Spontaneous tumors in urodele amphibians have been considered uncommon, and this resistance has sometimes been associated with the natural regenerative capacity of tissues in such species. This report describes spontaneous, nonpigmented, benign epitheliomas which were found in 44 of 1586 (2.8%) adult newts, Cynops pyrrhogaster, captured in central Japan. Both sexes were affected equally, usually with single tumors occurring at any epidermal site. Under laboratory conditions, these large tumors rapidly regressed or disappeared. Lesions were histologically noninvasive, hyperplastic epidermal reactions accompanied by loss of basal, subdermal melanocytes. Ultrastructurally, enlargement of intercellular spaces between tumor cells, increased pigment granules and membrane-bound cytoplasmic aggregates within the spaces, swollen rough endoplasmic reticula, degenerating pigment granules, and altered corneal cells were noted. Virus-like particles were observed in one tumor cell. Prelminary attempts failed to demonstrate transmissibility of the tumor, and no new cases arose under laboratory conditions. The cause of these tumors in the Japanese newt remains unknown, and it is suggested that if a viral agent is involved then other environmental cofactors (diet, temperature, or water constituents) are required for its expression.

Animals↗
PubMed1978

Experimental production of diffuse colitis in rats.

Diffuse, topical application of dilute acetic acid to the serosal surface of rat colon, or standardized intraluminal (per rectum) instillation induced a reproducible, diffuse colitis in a dose-response manner. These lesions were reproduced with 100% reliability and were evaluated up to 60 days when healing occurred. Histopathological features of this chemically induced colitis were diffuse ulceration of the distal colon, occurrence of pseudopolyp-like structures, alterations in crypt depth and mucus secretion, and a transmural, nonspecific inflammatory response.

Acetates↗
PubMed1977

Seabirds--a possible environmental factor in gastric cancer in Newfoundland.

Because of the high incidence of gastric cancer in fishermen, in seabird catchers, and in regions generally associated with a temperate or cool marine environment, the association of seabirds with gastric cancer risk was investigated regionally in Newfoundland. Cartographic plotting and correlation analyses of 23 individual or combined regions of Newfoundland with respect to M, F or M + F mortality rates showed a close similarity between high risk areas and large seabird aggregations which were in the southeast region of the island. Coastal fish processing plants were also prevalent focal points in this region between fishermen and seabird populations, suggesting that a chemical or viral carcinogen should be sought within this triad of fishermen, seabirds, and fish plants.

Animals↗
PubMed1976

Novel telemetric system for extraluminal measurement of gastrointestinal motility.

A frequency-modulated, telemetric system with a transducer sensitive to variation in distance between two points was developed and used to measure in vivo small intestinal motor function in unanesthetized dogs. The construction of the system and one application of it to the study of gastrointestinal motility is described. Data were recorded after fasting, 1 h after feeding a standardized meat meal, and after intravenous injections of pentagastrin. A significant increase in motility was seen after pentagastrin injections and feeding as compared to the motility pattern seen in a fasting animal, and the telemetric system was proven adequate for in vivo measurement of motility of the gastrointestinal tract.

Animals↗
PubMed1976

Experimental colitis.

Ulcerative colitis and Crohn's disease are complex, problematic diseases of unknown etiology in man, and appropriate experimental models would be useful in elucidating their pathogenesis and treatment. Although there have been numerous attempts to produce inflammatory ulcerative colonic disease in laboratory animals resembling those human disease forms, none has been entirely successful. Investigators have conducted experiments involving almost every etiological factor suggested for initiation of these diseases. The methods reviewed in this paper include production of experimental colitis by vascular impairment, and immunological methods such as bacterial infection, allergic reactions, direct and indirect hypersensitivity reactions, as well as autoimmune mechanisms. The results of carrageenan-induced colitis, irradiation, dietary, and drug-induced techniques are also discussed and the frequency and nature of spontaneous colonic lesions in animals is summarized.

Adult↗
PubMed1976

[The epidemiology of gastric cancer (author's transl)].

Gastric cancer is a highly fatal, common form of cancer in many countries and its medical, surgical, radiologic or combined treatment is very problematic. Thus, a search for its cause and prevention may be more promising than a search for its cure. Epidemiologic data from international studies suggest that environmental factors are more influential than genetic ones in the pathogenesis of gastric cancer, although its causes have not yet been identified. It is likely that the disease has a multi-factorial pathogenesis and that an ingested carcinogen may exert its influence at a time of enhanced susceptibility (damaged mucosa, older age, etc.), particulary in individuals with inherent, elevated risk (males, selected hereditary background etc.). In general, dietary studies have been less rewarding than occupational and geographic-pathologic analyses; such investigations may eventually identify the crude sources of carcinogens which then can be isolated by chemical means.

Asbestos↗