PubMed Health⌕ Search

Biomedical subjects

M Morin

Publications and source records attributed to M Morin.

At least 19 recordsLinked to original sources
PubMed1992

[Importance of the role of dose rate on tumor induction in rats after radon inhalation].

Lung cancer can be induced in rats, by radon daughter products, after exposure as low as 25 WLM (80 mJ.h.m-3) protracted over 4 to 6 months with a dose rate of 100 to 150 WL (2 to 3 mJ.m-3). The incidence of lung cancer is not increased and is equal to that of controls when the same cumulated dose is protracted over 18 months at 2 WL (0.042 mJ.m-3).

Administration, Inhalation↗
PubMed1992

Validity and limitations of animal experiments in assessing lung carcinogenicity of cadmium.

Several cadmium compounds have been observed to induce in rats, but in rats only, a dose-dependent increase in lung cancer. A similar sensitivity to lung cancer induction in both humans and rats can be deduced from a comparison of the histogenesis of tumours and the dose response to radiation, since similar numbers of DNA lesions are produced. Since the carcinogenic action of cadmium is limited to the site of deposition, the toxicokinetics of inhaled particles in human and rodents are discussed in relation to the exposure of the respective target cells in both species. It is stressed that the rat may be much more sensitive to the induction of cancer following the retention of poorly soluble compounds. A comparison of the possible dose-effect response in humans and the dose response in rats showed that the shape of the "dose" response cannot be extrapolated. Finally, clonogenicity and DNA repair of tracheal cells sublethally exposed in vitro to cadmium differ significantly in rats and hamsters. This may explain why hamsters exposed in vivo do not develop tumours.

Animals↗
PubMed1991

Experimental infection of newborn pigs with an attaching and effacing Escherichia coli O45:K"E65" strain.

The ability of a nonenterotoxigenic, K88-negative porcine Escherichia coli strain of serogroup O45:K"E65" to induce attaching-effacing lesions was investigated in newborn pigs. Typical attaching-effacing lesions, characterized by intimate adherence of bacteria to mature enterocyte brush borders with effacement of the microvilli, were observed on light and electron microscopy. Bacteria were also seen in intracytoplasmic vacuoles of mature enterocytes and, in areas of heavier colonization, in the lamina propria of the intestinal mucosa. A moderate inflammatory response with mild focal ulceration of the intestinal mucosa was observed. In a sequential study, we observed that the attaching-effacing lesions were well established in the duodenum, jejunum, and ileum at 12 h postinoculation but did not develop in the cecum and colon until 24 to 48 h postinoculation, although bacteria had colonized the latter areas as early as 12 h postinoculation. Initially, bacteria were very intimately attached, with an irregular arrangement on the enterocyte apical cell membrane, and subsequently reoriented to form a typical palisade arrangement with a narrow regular gap between the bacterial cell wall and the enterocyte apical cell membrane. This phenomenon of early intimate attachment of irregularly disposed bacteria has not been reported for human enteropathogenic attaching and effacing E. coli and could represent a new and different mechanism of attachment and effacement to intestinal epithelial cells.

Animals↗
PubMed1991

Identification of atypical rotaviruses in outbreaks of preweaning and postweaning diarrhea in Québec swine herds.

Intestinal contents of diarrheic pigs from 120 outbreaks of diarrhea were examined for the presence of atypical rotaviruses. Pigs involved in these outbreaks were aged two days to five weeks and samples collected over a period of one year originated from different regions of the province of Québec. Samples were analyzed by polyacrylamide gel electrophoresis (PAGE) for the presence of viral RNA and genome profiles were compared to those of porcine rotavirus A/OSU, B/Ohio and C/Cowden. Based on electropherotypes both typical (group A) and atypical (groups B and C) rotaviruses were identified. Rotaviruses could be demonstrated in 25.8% of outbreaks and together atypical rotaviruses accounted for 46.7% of rotavirus-positive outbreaks. Other common enteropathogens were often present in conjunction with rotaviruses in the preweaning and postweaning outbreaks studied.

Animals↗
PubMed1991

Plasma vitamin A and E in type 1 (insulin-dependent) and type 2 (non-insulin-dependent) adult diabetic patients.

Vitamin A and E status was studied in 35 type 1 (insulin-dependent) and 35 type 2 (non-insulin-dependent) diabetic patients and in 30 control subjects. Vitamin A blood concentration was significantly decreased in type 1 and increased in type 2 diabetic patients as compared to control subjects. No correlation was found between vitamin A blood concentration and blood glucose control as evaluated with HbA1c. Blood Vitamin E concentrations were significantly increased in both groups of diabetic patients and were statistically correlated with blood cholesterol, apoprotein B and triglycerides, but not with HbA1c.

Adolescent↗
PubMed1991

[Role of age at the moment of irradiation on the induction of tumors].

The probability that rats develop tumours following a 3 Gy exposure to gamma rays from cobalt 60 was observed to depend on age at exposure. Lifetime excess of neoplasia decreased by a factor of about 10 in 9-month-old rats as compared to animals irradiated in utero. The 3-month age group developed slightly fewer tumours than the group irradiated in utero, and tumour location was different. The higher incidence of tumours observed in the foetal group was mainly due to the high sensitivities of central nervous system and gonads during organogenesis.

Adrenal Gland Neoplasms↗
PubMed1990

Postoperative myocardial infarction and cardiac death. Predictive value of dipyridamole-thallium imaging and five clinical scoring systems based on multifactorial analysis.

Sixty-six patients unable to complete a standard preoperative exercise test because of physical limitations were studied to determine the predictive value of individual clinical parameters, of clinical scoring systems based on multifactorial analysis, and of dipyridamole-thallium imaging before major general and vascular surgery. Study endpoints were limited to postoperative myocardial infarction or cardiac death before hospital discharge. There were nine postoperative cardiac events (seven deaths and two nonfatal infarctions). There was no statistical correlation between cardiac events and preoperative clinical descriptors, including individual clinical parameters, the Dripps-American Surgical Association score, the Goldman Cardiac Risk Index score, the Detsky Modified Cardiac Risk Index score, Eagle's clinical markers of low surgical risk, and the probability of postoperative events as determined by Cooperman's equation. There were no cardiac events in 30 patients with normal dipyridamole-thallium scans or in nine patients with fixed myocardial perfusion defects. Of 21 patients with reversible perfusion defects who underwent surgery, nine had a postoperative cardiac event (sensitivity, 100%; specificity, 43%). In the six other patients with reversible defects, preoperative angiography showed severe coronary disease or cardiomyopathy. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically before major general and vascular surgery, whereas dipyridamole-thallium imaging successfully identified all patients who sustained a postoperative cardiac event.

Aged↗
PubMed1990

Standing views to differentiate gallbladder or bile leak from duodenal activity on cholescintigrams.

Confusing a gallbladder or bile leak with duodenal activity is a common source of error in the interpretation of cholescintigrams. Techniques such as supplementary oblique views, delayed views, the "water test," dynamic display and combined cholescintigraphy and ultrasound have been used with varying degrees of success. As illustrated in two cases, supplementary standing views provide a simple alternative method to differentiate gallbladder from small bowel activity.

Adolescent↗
PubMed1990

Rotaviral enteritis in a raccoon.

A hand-reared raccoon (Procyon lotor) kit had severe diarrhea and died within 24 hr. Gross and histopathologic findings were compatible with a diagnosis of viral enteritis. The immunoperoxidase test revealed rotavirus group A antigen in the intestinal mucosa. This is the first record of rotaviral enteritis in a raccoon.

Animals↗
PubMed1990

[Carcinogenic effects of low-dose gamma ray irradiation].

For a dose of 3 Gy delivered by cobalt 60 gamma rays on rats, a reduction of the dose rate by a factor of 60 decreased the carcinogenic effectiveness by a factor of about 5. This decreased effect was essentially observed for carcinomas.

Animals↗
PubMed1990

Porcine group C rotavirus as a cause of neonatal diarrhea in a Quebec swine herd.

A porcine group C rotavirus was found to be the unique cause of a problem of enzootic neonatal diarrhea in a minimal disease herd composed of 190 sows on a continuous farrowing program. During the outbreaks of diarrhea, 10 to 80% of the litters were affected with a morbidity rate of 100% and case fatality rates of 5 to 10%. Clinical signs began 24 to 48 h after birth and were characterized by a profuse yellow diarrhea lasting a few days. Piglets from different outbreaks of diarrhea were necropsied. They had multifocal villous atrophy in the small intestine, especially in the ileum. Group C rotavirus was demonstrated by direct immunofluorescent staining of frozen intestinal sections and by polyacrylamide gel electrophoresis of viral RNA extracted from the intestinal contents of diarrheic piglets. The infection with clinical illness and lesions was reproduced experimentally in newborn piglets by oral inoculation of a suspension prepared from a pool of intestinal contents from diarrheic piglets.

Animals↗