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Biomedical subjects

J C Mitchell

Publications and source records attributed to J C Mitchell.

At least 55 records · Page 3Linked to original sources
PubMed1988

Effects of albumin on fatty acid, protein, and eicosanoid levels in rat mesenteric arterial bed perfusions.

Male rats were maintained on rat chow supplemented with 5% evening primrose oil for 2 weeks. Mesenteric perfusions were then performed, half with and half without albumin. Albumin was found to increase the yield of fatty acids and reduce eicosanoid levels. Perfusions without albumin decreased fatty acid release, increased eicosanoid levels, and showed a decrease in protein concentration over time. The value of albumin as a "trap" for fatty acids during perfusion experiments depends upon what parameter is to be measured.

Albumins↗
PubMed1987

The induction of micronuclei in human lymphocytes by low doses of radiation.

The appearance of micronuclei (MN) is delayed with respect to cell division in populations of irradiated human lymphocytes, so that the length of time in culture, as well as the number of divisions, is a factor in MN assays. Using two assays that control for cell kinetics, we measured the yield of cells with MN exposed to graded doses of 60Co gamma rays and 90KVP X-rays. The yields showed a non-linear increase with dose. They can be represented by two straight lines: the one in the range below 0.15 Gy has a slight slope, the other in the range above 0.15 Gy has a significantly greater slope. The radical scavengers cysteamine and glycerol, which reduced the MN yields sharply at 3 Gy, were less effective at 0.3 Gy, indicating that terminal deletions arising from the direct ionization of DNA are a major source of the MN induced by low radiation doses. It is likely that the non-linear dose response is due to the saturation of a DNA repair process.

Cell Cycle↗
PubMed1986

The relation of feeding and activity following septal lesions in rats.

The patterns of intake of liquid diet and water were recorded in diet-deprived rats with septal lesions and neurologically intact controls during the first hour of diet access. The occurrences of grooming, resting/sleeping, and exploring were also recorded. Both groups of rats consumed similar amounts of diet in one meal during the 1-hr diet access period. Control rats consumed the meal in one prolonged bout of eating, whereas rats with septal lesions consumed the meal in numerous small bouts of eating. Rats with septal lesions were active for longer periods, exhibiting continuous alternation of brief bouts of eating, drinking, exploring, and resting throughout the meal. In tests in which water was not available during the diet access period, both groups of rats increased their intrameal bout size, but rats with septal lesions still showed much smaller bouts of ingestion than did controls. These data suggest that the small-bout pattern of ingestion may reflect a general disruption in the control of behavioral sequences, rather than processes uniquely related to the regulation of eating or drinking.

Animals↗
PubMed1985

Identification of psoralen, 8-methoxypsoralen, isopimpinellin, and 5,7-dimethoxycoumarin in Pelea anisata H. Mann.

5,7-dimethoxycoumarin and isopimpinellin, together with the well-known phototoxic, photo-irritant furanocoumarins psoralen and 8-methoxypsoralen, were isolated and identified from leaves and fruits of Pelea anisata H. Mann, a plant whose fruit are used in the construction of mohikana leis used in parts of the Hawaiian Islands. The presence of phototoxic furanocoumarins would explain the occurrence of photodermatitis in the wearers of the leis.

Coumarins↗
PubMed1984

Membranoproliferative glomerulonephritis. A prospective clinical trial of platelet-inhibitor therapy.

Forty patients with Type I membranoproliferative glomerulonephritis were treated for one year with dipyridamole, 225 mg per day, and aspirin, 975 mg per day, in a prospective, randomized, double-blind, placebo-controlled study. At the base line, the half-life of 51Cr-labeled platelets was reduced in 12 of 17 patients. The platelet half-life became longer and renal function stabilized in the treated group, as compared with the placebo group, suggesting a relation between platelet consumption and the glomerulopathy. The glomerular filtration rate, determined by iothalamate clearance, was better maintained in the treated group (average decrease, 1.3 ml per minute per 1.73 m2 of body-surface area per 12 months) than in the placebo group (average decrease, 19.6). Fewer patients in the treated group than in the placebo group had progression to end-stage renal disease (3 of 21 after 62 months as compared with 9 of 19 after 33 months). The data suggest that dipyridamole and aspirin slowed the deterioration of renal function and the development of end-stage renal disease.

Adolescent↗
PubMed1984

A test for the practical evaluation of male fertility by acridine orange (AO) fluorescence.

A new and practical test for evaluating the fertility of a male subject has been developed. Twenty-eight donors whose semen had induced at least one pregnancy resulting in a normal delivery and 61 patients attending our infertility clinic were studied. Semen smears stained with acridine orange were read on a fluorescence microscope; sperm heads appeared either green (fertile) or red ( nonfertile ). We introduce the concept of an "effective sperm count" which is obtained by multiplying the percentage of green-fluorescing sperm by the actual sperm count. Of our fertile subjects, 27 of 28 (96.4%) exhibited an effective sperm count of greater than or equal to 50 million/ml, while 60 of 61 (98.3%) infertile patients fell below this value. The percent green correlates with neither actual sperm count nor motility, indicating that this test measures a new parameter of male fertility.

Acridine Orange↗
PubMed1984

Results of treatment of renal failure by means of home hemodialysis.

Of 630 patients who began hemodialysis treatment for chronic renal failure between 1965 and 1977, 147 successfully completed training for home hemodialysis. Patient compliance was satisfactory, as reflected by the results of monthly blood chemical values, hematocrits, and weight gain between dialysis. Although only 15 patients had previous myocardial infarctions and 4 had had strokes before beginning dialysis, 9 patients subsequently experienced acute myocardial infarctions and 14 had strokes. Of the 45 patients who died while being maintained by hemodialysis, 24 had cardiopulmonary complications and 6 had strokes. Despite such complications, 70 patients were gainfully employed and 32 were active at home or at school, whereas 29 were totally disabled. At last follow-up, 74 remained on home hemodialysis, 53 had functioning renal allografts, and the rest of the patients were being maintained in our dialysis center, had transferred elsewhere, or were being maintained by peritoneal dialysis. The overall estimated 5-year survival rate was 56%, whereas the estimated 5-year survival rate for those maintained by home hemodialysis alone was 52%.

Adolescent↗
PubMed1984

Results of treatment of center hemodialysis patients.

Four hundred eighty-three patients were maintained by hemodialysis in an outpatient hemodialysis center at the Mayo Clinic between 1963 and 1977. Although only 18 patients had experienced a myocardial infarction and 6 had had a cerebral infarction before beginning dialysis, 30 subsequently had acute myocardial infarction and 45 had a stroke. These two complications accounted for 48 of the 98 deaths that occurred during maintenance dialysis. Despite such complications, 183 patients were employed, 124 remained active at home or at school, and 115 were totally disabled. Survival of patients maintained solely by dialysis was 52% at 5 years. For the group as a whole, including patients who received their first allograft, the survival rate at 5 years was 65%.

Adolescent↗
PubMed1983

The current status of the weed Parthenium hysterophorus L. as a cause of allergic contact dermatitis.

The dissemination of allergenic plants as horticultural introductions, or in the case of the weed Parthenium hysterophorus L. apparently by chance, can have undesirable results. This species of the Compositae family, native to the Caribbean region, has spread widely in India, causing allergic contact dermatitis from its content of sesquiterpene lactones, and has recently appeared in Australia. The clinical features consist of dermatitis of the exposed skin surfaces from direct contact with the weed, but resembling photodermatitis. In fact, contact dermatitis from the plant can coexist with light sensitivity. The plant does not show phototoxic activity but may contain an unidentified photoallergen. Since plant hairs and the pollen contain sesquiterpene lactones, they can probably cause airborne contact dermatitis. Attempts to control spread of the plant have so far not been successful.

Chemical Phenomena↗
PubMed1983

Continuous ambulatory peritoneal dialysis. Three years' experience at the Mayo Clinic.

From January 1979 through January 1982, 69 patients with end-stage renal failure of various causes were treated by continuous ambulatory peritoneal dialysis. The dialysis was adequate and stable in all except four patients; two of these four became irreversibly uremic, and the other two had inadequate ultrafiltration. Hemoglobin levels increased initially and remained stable in all but two patients. In our experience, metabolic problems included control of secondary hyperparathyroidism, adequate protein nutrition, progressive neuropathy, abnormal lipoprotein profiles, and excessive weight gain. Technical problems included recurrent peritonitis, maintenance of adequate peritoneal access, and development of abdominal hernias. In general, all but two patients remained enthusiastic about this type of therapy despite inherent problems. The long-term potential of continuous ambulatory peritoneal dialysis remains uncertain at this point, but for most patients, adequate short-term treatment by this method is a reasonable alternative to hemodialysis.

Adult↗