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Biomedical subjects

O Schaefer

Publications and source records attributed to O Schaefer.

At least 19 recordsLinked to original sources
PubMed1990

Cyclosporine monitoring in liver allograft recipients: two distinct patterns of blood level derangement associated with nephrotoxicity.

The parallel measurement of specific and nonspecific CyA levels by second generation radioimmunoassays based on monoclonal antibodies proved to be an effective procedure to monitor both parent CyA levels and the capacity to eliminate its metabolite. Using this monitoring procedure it could be shown that CyA-associated nephrotoxicity in the early course after liver transplantation is associated with two distinct patterns of blood level derangement. One pattern is characterized by increased parent drug levels, the other by an increased metabolite concentration resulting from severely disturbed CyA metabolite excretion. This raises the possibility that not only the parent drug but also some of its metabolites may exert nephrotoxic effects when present in excessively high concentrations. This finding provided the rationale for a therapeutic CyA-monitoring regimen taking into account both specific and nonspecific measurements. In liver transplant patients monitored according to this regimen and treated with quadruple immunosuppression the incidence and severity of CyA-associated nephrotoxicity was markedly reduced. The metabolite-associated type of nephrotoxicity was only found in patients with severely disturbed liver function.

Creatinine↗
PubMed1986

Adverse reactions to drugs and metabolic problems perceived in Northern Canadian Indians and Eskimos.

Eskimos and to a slightly lesser degree Northern Indians are extremely rapid acetylators as tested with isoniazid. They also tend to clear phenytoin rapidly as proven in Greenland Eskimos and supported by clinical observations in Canadian Eskimos. Most "silent gene" cholinesterase cases found in Canada came from the tiny minorities of Northern Indians and Eskimos and an even higher prevalence was found in an isolate of South Western Alaskan Eskimos. We found alcohol metabolism significantly slower in Northern Indians and Eskimos than Caucasians, which is at variance with findings in other Amerindian groups and Asiatic Mongoloids reflecting perhaps quite different physical and nutritional environments over long periods of time. Pecularities of sugar metabolism found in Natives of the Canadian Arctic and Sub-Arctic may also be best explained by the relative deficiency of carbohydrates in their traditional diet.

Adaptation, Biological↗
PubMed1985

Cell wall and DNA cosegregation in Bacillus subtilis studied by electron microscope autoradiography.

Cells of a Bacillus subtilis mutant deficient in both major autolytic enzyme activities were continuously labeled in either cell wall or DNA or both cell wall and DNA. After appropriate periods of chase in minimal as well as in rich medium, thin sections of cells were autoradiographed and examined by electron microscopy. The resolution of the method was adequate to distinguish labeled DNA units from cell wall units. The latter, which could be easily identified, were shown to segregate symmetrically, suggesting a zonal mode of new wall insertion. DNA units could also be clearly recognized despite a limited fragmentation; they segregated asymmetrically with respect to the nearest septum. Analysis of cells simultaneously labeled in cell wall and DNA provided clear visual evidence of their regular but asymmetrical cosegregation, confirming a previous report obtained by light microscope autoradiography (J.-M. Schlaeppi and D. Karamata, J. Bacteriol. 152:1231-1240, 1982). In addition to labeled wall units, electron microscopy of thin sections of aligned cells has revealed fibrillar networks of wall material which are frequently associated with the cell surface. Most likely, these structures correspond to wall sloughed off by the turnover mechanism but not yet degraded to filterable or acid-soluble components.

Acetylglucosamine↗
PubMed1984

The changing picture of neoplastic disease in the western and central Canadian Arctic (1950-1980).

Data on 239 verified cases of malignant disease diagnosed from January 1950 through December 1980 in 104 male and 135 female Inuit from the western and central Canadian Arctic were reviewed. Tumours of the salivary glands, kidney and nasopharynx were the most frequent between 1950 and 1966, but their frequency declined thereafter. The most frequent tumours in the most recent period studied were lung, cervical and colorectal cancers. Breast cancer was absent before 1966 and was found in only 2 of 107 Canadian Inuit women stricken with cancer from 1967 to 1980, whereas the recent rates in the longer-acculturated Inuit of Alaska and Greenland have approached those prevailing in modern Western women. The Inuit appeared to be more prone than other North Americans to cancer of the esophagus, liver and ampulla of Vater but less prone to cancer of the skin, prostate, pancreas and stomach. The gradual reduction in the relative frequency of tumours typical for traditional Inuit and their replacement by "modern" tumours appear to reflect the history of local acculturation. Various factors in the environment, nutritional habits and lifestyle may contribute to the unusual and changing epidemiologic patterns of cancer in Canadian Inuit.

Adult↗
PubMed1980

Respiratory function impairment and cardiopulmonary consequences in long-time residents of the Canadian Arctic.

Spirometry, roentgenography and electrocardiography were performed during community health surveys in 1976-78 in 176 Inuit and other long-time residents of the northeastern (Arctic Bay) and western (Inuvik) Canadian Arctic, and the results were related to age, ethnic origin, occupation and history of climatic exposure, smoking and hospitalization for tuberculosis. In Arctic Bay the young men showed excellent respiratory function, normal-sized pulmonary arteries and normal electrocardiograms, but abnormalities of all three types were increasingly frequent and severe after age 25. The forced mid-expiratory flow (FMF) fell to less than 50% of the norm by age 40, and dilatation of the pulmonary artery, hypertrophy of the right ventricle, right bundle branch block and a pseudoinfarction pattern on the ECG were frequently associated. In contrast, the men in Inuvik, an urbanized centre, maintained above normal respiratory function until age 40, and the FMF and pulmonary artery diameter remained normal in the older men except for Inuit and white trappers over 60 years old who had run fox trap lines along the Arctic coast in the 1920s and 30s. These data suggest that inhalation of extremely cold air at maximum ventilation may be a prime factor in the chronic obstructive lung disease of Inuit hunters, whereas smoking has only a minor role and hospitalization for tuberculosis appears to protect from rather than contribute to this disorder.

Adolescent↗
PubMed1978

Nutrient levels of some foods of Eskimos from Artic Bay, N. W.T., Canada.

Native food samples of caribou, seal, and arctic char were collected from resident Eskimos in Arctic Bay, N.W. T., and analyzed for nutrients. Caribou and seal meats were similar in protein and fat content in comparison with beef. Arctic char was above the average in protein and fat content for fish. Ascorbic acid was present in significant amounts only in baby seal liver. Thiamin, riboflavin, vitamin B12, folacin, and pantothenic acid content ranged from average to high for seal and carbiou meat, respectively, in comparison to published values for pork and beef. The vitamin B6 content of caribou meat was comparable to average values reported for pork and beef but was lower in seal meat. Baby seal liver contained similar levels of thiamin, riboflavin, vitamin B12, folacin, and pantothenic acid and less vitamin B6 than those reported for pork, beef, calf, and lamb liver. Arctic char was not appreciably different in these vitamins from other fish. The iron content of the Eskimo foods was higher than the meat group of the mixed Canadian diet. The macro mineral nutrients in these foods were comparable to those in beef and fish. The amino acid composition of caribou and seal meat was similar to beef, except that seal meat had a lower content of sulfur-containing amino acids and a much higher content of histidine. The sample of seal and arctic char were relatively high in concentrations of long-chain unsaturated fatty acids.

Amino Acids↗
PubMed1977

Are Eskimos more or less obese than other Canadians? A comparison of skinfold thickness and ponderal index of Canadian Eskimos.

Skinfold thickness, height, and weight measurements were recorded from 1964 through 1970 for more than 1,000 adult Eskimos who resided in the Central and Eastern Canadian Arctic. Among the men and women of all age groups, 70 to 83% had a low ponderal index (PI less than 12.5). Nutrition Canada reported similar rates in 200 adult Eskimos and therefore considered Eskimos, especially Eskimo men, as more obese than other Canadians. Thin skinfolds were found in most Eskimo men, including those with a low PI. The usefulness of the PI or other height/weight indices for appraisal of body fatness and prevalence of obesity in different population groups is questioned. Marked sex differences were found in the ratio of the skinfold thickness over the triceps to the mean thickness of two sites on the trunk (subscapular and suprailiac). Thus, use of the arm plus trunk sites provides important information about subcutaneous fat distribution, and comparisons of prevalence of obesity in different sex and age groups based only on arm skinfold measurements may be inappropriate.

Abdomen↗
PubMed1975

The changing pattern of neoplastic disease in Canadian Eskimos.

The records of the two main referral centres for the western and central Arctic were reviewed for Eskimo patients with cancer diagnosed between 1949 and 1974 inclusive. To these were added the records for the past 6 years of patients from the eastern Arctic, giving the toatal of 180 histologically proved cases of malignant disease. Athe data were analysed for prevalence, relative frequency, geographic distribution and changes with time of the various neoplasms. Salivary gland and renal neoplasms have in recent years been displaced by cancer of the lung and uterine cervix as the most common malignant tumours in Canadian Eskimos. The prevalence of lung cancer in Eskimo women, particularly of the central Artic, is striking. Cancer of the nasopharynx kept the same relative position during early and late years of the survey period. Breast cancer is still uncommon in Eskimos. Lactation rather than gestation history appeared to be an important protective factor. Cases of cervical cancer outnumbered those of breast cancer by 18 to 4, in sharp contrast to the relative proportions of these tumours in all Canadian women.

Adolescent↗
PubMed1975

Twenty-four hour urinary excretion of vitamins, minerals and nitrogen by Eskimos.

In 1971-1972, urines were collected over 24 hours from ambulatory Iglooligmiut who ranged in age from 6 to 76 years. Collections were made every 3-4 months over a calendar year. The mean of each individual's two to four collections was used as the best estimate of that person's average daily excretion for nitrogen, thiamin, riboflavin, N'-methylnicotinamide, calcium, phosphorus, and magnesium. The excretion of the three B vitamins by all age groups was high when compared with interpretive standards. Urea nitrogen comprised 80-90% of total nitrogen excreted by all age groups. Twenty-four-hour mineral excretions did not differ with age and sex group except that adult men excreted significantly more phosphorus. Urinary urea nitrogen and phosphorus were linearly related, suggesting that they have a common source; namely, meat. Winter was generally the season of lowest excretion of the nutrients assayed. Since these nutrients are available from imported foods, particularly during the winter, it would appear that even in the winter the Iglooligmiut are more dependent on hunting and fishing for sources of these nutrients than on the well-stocked commercial grocery outlets.

Adolescent↗