Search PubMed⌕ Search

Biomedical subjects

J Johnson

Publications and source records attributed to J Johnson.

At least 739 records · Page 41Linked to original sources
PubMed1976

Bilateral adrenalectomy in treatment of disseminated breast cancer.

Forty-three patients underwent bilateral adrenalectomy for advanced breast cancer at the Hospital of the University of Pennsylvania from 1960 to 1974. Fourteen patients (32 per cent) experienced an objective remission. There was no difference in the initial free interval between the responders and nonresponders. Premenopausal patients who improved after surgical castration or androgen therapy and postmenopausal patients who responded to estrogen therapy and its subsequent withdrawal had a greater response to adrenalectomy. Twenty-three of the forty-three patients who underwent bilateral adrenalectomy had evidence of metastatic involvement in at least one of the excised adrenal glands. Results show that patients who responded to previous therapy had a longer survival after adrenalectomy.

Adrenalectomy↗
PubMed1976

Plasma renin activity, plasma angiotensin II and extracellular fluid volume in patients after renal transplantation.

1. Patients with cadaveric renal transplants and plasma creatinine less than 177 micronmol/l who had their own kidneys removed were studied. 2. The renin-angiotensin system appeared to behave in a normal fashion in response to alterations in sodium intake and posture. 3. The renin-angiotensin system had no major role in the establishment or maintenance of hypertension. 4. Mean arterial pressure was directly related to expansion of the extracellular fluid volume.

Angiotensin II↗
PubMed1976

Challenge of dogs with live enterotoxigenic Escherichia coli and effects of repeated challenges on fluid secretion in jejunal Thiry-Vella loops.

Dogs were evaluated as experimental models for the study of diarrheal disease produced by enterotoxigenic Escherichia coli. Although a suitable whole model for orogastric bacterial challenge could not be developed, chronic jejunal Thiry-Vella loops were used to study the secretory effects of multiple jejunal challenges with enterotoxin of either Vibrio cholerae or E. coli. The heat-stable and heat-labile E. coli enterotoxins could be differentiated clearly in this model. Sequential weekly challenges over a four-week period showed a significant decrease in loop secretory response to homologous enterotoxin, although levels of antitoxin in serum remained unchanged, a finding suggesting a local immune response. Dogs challenged with E. coli enterotoxin were markedly protected against subsequent challenge with V. cholerae enterotoxin; the converse was not true. Histologic studies of the loops showed only minimal atrophy, and results of absorption studies in the loops were normal. These studies suggest that mongrel dogs are resistant to colonization by enterotoxigenic E. coli and partially resistant to challenge with enterotoxin, perhaps on an immune basis due to prior antigenic exposure. Multiple challenges with enterotoxin effect a decreased secretory response; this finding also suggests a local immune mechanism.

Animals↗
PubMed1976

Educational materials reviewed for AVLINE.

The need for a central source of information regarding the availability, suitability, and quality of educational materials has led to the development of AVLINE. AVLINE is a computer information service available through the MEDLARS system of the National Library of Medicine. The Association of American Medical Colleges is gathering information from faculty members concerning useful materials and is bringing together content specialists, instructional designers, and technical specialists to review these materials. Information on materials that are recommended is provided to the National Library of Medicine to be cataloged, indexed, and abstracted for ultimate listing in AVLINE. Twenty-eight percent of the material has not been recommended; the many reasons for low ratings are categorized under content quality, instructional design, and technical quality.

Audiovisual Aids↗
PubMed1976

Enzymatic sulfation of steroids: I. The enzymatic basis for the sex difference in cortisol sulfation by rat liver preparations.

Liver cytosols from female rats contained 6-8 times as much cortisol sulfotransferase activity as those from males. The reaction product, with both sexes, appeared to be cortisol-21 sulfate. Liver cytosols from male and female rats showed different substrate preferences when tested with cortisol, estradiol-17beta, testosterone, and dehydroepiandrosterone, suggesting that they contained different steroid sulfotransferases. Fractionation of cytosols from female rats on DEAE Sephadex A-50 columns resolved 3 steroid sulfotransferases, or families of steroid sulfotransferases (STI, STII, and STIII). These enzymes exhibited different substrate preferences. STI and STIII had the greatest preferences for cortisol, although none of the enzymes was restricted to the glucocorticoid. Fractionation of cytosols from males resolved 2 sulfotransferases which eluted at salt concentrations identical to STII and STIII from females. Study of the development of cortisol sulfotransferase activity with age showed little enzyme activity in rats of either sex at 2 days after birth. Enzyme activity developed in parallel in both sexes until 30 days after birth. Then the sulfotransferase activity began to rise in females and to drop in males. By day 50-55 both sexes attained adult enzyme levels. STII was the major enzyme in all immature animals. STIII was also present, but STI was absent. In male rats STIII activity began to rise by day 30. Soon after, STII activity began to drop. By day 55 adult male patterns developed. STI was the major enzyme in females by day 30. In ensuing days all 3 enzyme levels rose, until by day 50 adult enzyme patterns and levels were attained. The data suggest that the ovaries stimulated production of all 3 sulfotransferases and that the testes suppressed production of STII (and perhaps STI). Preliminary studies with gonadectomized rats supported the suppressive role of the testes, but suggested that the ovaries were not the only factor controlling sulfotransferase production in female rats.

Age Factors↗
PubMed1976

Coccidiosis: effects of high environmental temperatures on anticoccidial protection.

In a series of nine experiments birds subjected to heat-stress showed decreases of 9 to 61 percent in feed intake. In only one of these experiments, involving E. acervulina and monensin, was there sufficient reduction of anticoccidial intake to partially nullify effects of drug protection. In this case, a 40 percent decrease in monensin intake resulted in significantly higher lesion scores (1.9 vs. 1.0) (P less than or equal to 0.05) in birds maintained at 32 C. for days 1 to 7 postinfection (P.I.) compared to controls maintained at 20C. No other failures due to heat stress occurred with this anticoccidial in three other trials with E. acervulina or or five trials involving E. tenella infection. In one experiment E. tenella coccidiosis (lesion scores 0.7 vs. 1.1) was more severe in the cool environment than in birds under heat-stress from 2 to 7 days P.I. Similarly, less severe lesions of E tenella (0.4 vs. 0.8) occurred during heat-stress (32 C) than in controls maintained at 11 C. in zoalene-fed and unmedicated control birds. No differences in lesion scores occurred in birds in hot versus cool room environments in two experiments involving sulfaquinoxaline or one with robenidene and E. tenella infection. E tenella lesions inunmedicated controls were significantly more severe in the cool than the hot environment in one experiment. Results from these experiments suggest that decreases in feed and anticoccidial intake during heat-stress could seldom be the cause of coccidiosis breaks under field conditions.

Animals↗
PubMed1976

Turnover of erythrocyte protoporphyrin, with special reference to bovine porphyria and iron deficiency anemia.

Available data from human subjects suggests that most of the pools of free protoporphyrin in circulating erythrocytes have T 1/2 values which range from less than 1 hour to approximately 2 weeks. An exception was observed in 2 cows with erythropoietic ("congenital") porphyria. During the several months which followed the simultaneous injection of 14C- and 3H-labelled glycine and ALA, changes in the specific activities of both free- and hemoglobin-protoporphyrin were similar. Since erythropoietic porphyria in the bovine differs from that in the human mainly in the elevated values of free erythrocyte protoporphyrin in the former, it is suggested that this prolonged T 1/2 (equal approximately to the red cell life span) may account for the elevated values seen in the bovine. Variable ratios of red cell/fecal protoporphyrin concentrations reported in other diseases are also believed to be due largely to T 1/2 differences in porphyrin pools. Recorded fluorescence and excitation spectra of blood showed the single fluorescence band of "free" porphyrin in bloods of normal and porphyric cows and of patients with erythropoietic porphyria, protoporphyria, and sideroblastic anemia. The 2 band zinc complex spectrum was found, as expected, in blood of subjects with Pb poisoning and Fe deficiency anemia. T 1/2 values of 1 to 2 weeks were calculated for red cell protoporphyrin from previously published data of patients with Fe deficiency anemia who were treated effectively with iron.

Aminolevulinic Acid↗