Search PubMed⌕ Search

Biomedical subjects

J A Collins

Publications and source records attributed to J A Collins.

At least 109 records · Page 6Linked to original sources
PubMed1981

A comparison of estrogen use by women with endometrial cancer, gynecologic disorders, and other illnesses.

Exogenous estrogen use was determined by interview in 206 endometrial cancer patients, 191 women with nonmalignant gynecologic disorders, and 199 women with other illnesses. Separate comparisons of these patients with gynecologic and other illness control subjects provided estimates of the risk of endometrial cancer among estrogen users, adjusted for the effects of confounding variables, of 1.5 (95% confidence limits 0.9 and 2.7) and 4.8 (2.7 and 8.4), respectively. In both comparisons, risk increased with increasing duration of use; regardless of duration of use, risks were higher among users of estrogen within 12 months of diagnosis than among past users. The effects of bias, including surveillance bias, on the results were considered and it was concluded that the true risk was not less than the case/gynecologic control estimate and was likely to approach the case/other control estimate.

Adenocarcinoma↗
PubMed1981

FSH and testosterone effects in seminiferous tubules of immature hypophysectomized rats.

The effects of follicle-stimulating hormone (FSH) and testosterone on the development of the cytosolic germ cell adenylate cyclase and germ cell morphology in rats hypophysectomized at 29 days of age were studied. Following hypophysectomy, the adenylate cyclase content fell to marginal levels and germ cell development ceased at the late pachytene stage. Testosterone treatment led to a moderate increase in the cytosolic enzyme content and to progression of spermatid cell development to stages 8-12. FSH treatment with doses of 80-100 micrograms/day restored enzyme content to levels seen in control rats, as well as progression of germ cell development up to stages 15-16, i.e., to the same stages present in age-matched control (sham-operated) rats. The results indicate that in immature rats FSH is essential for spermatid cell maturation as is evidenced by its ability to stimulate the formation of cytosolic germ cell adenylate cyclase to quantitatively normal levels, as well as to stimulate the development of spermatid cells.

Adenylyl Cyclases↗
PubMed1981

Epinephrine plasma thresholds for lipolytic effects in man: measurements of fatty acid transport with [l-13C]palmitic acid.

To determine the plasma epinephrine thresholds for its lipolytic effect, 60-min epinephrine infusions at nominal rates of 0.1, 0.5, 1.0, 2.5, and 5.0 micrograms/min were performed in each of four normal young adult men while they also received a simultaneous infusion of [1-13C]palmitic acid to estimate inflow transport of plasma free fatty acids. These 20 infusions resulted in steady-state plasma epinephrine concentrations ranging from 12 to 870 pg/ml. Plasma epinephrine thresholds for changes in blood glucose, lactate, and beta-hydroxybutyrate were in the 150--200-pg/ml range reported by us previously (Clutter, W. E., D. M. Bier, S. D. Shah, and P. E. Cryer. 1980. J. Clin. Invest. 66: 94--101.). Increments in plasma glycerol and free fatty acids and in the inflow and outflow transport of palmitate, however, occurred at lower plasma epinephrine thresholds in the range of 75 to 125 pg/ml. Palmitate clearance was unaffected at any steady-state epinephrine level produced. These data indicate that (a) the lipolytic effects of epinephrine occur at plasma levels approximately threefold basal values and (b) lipolysis is more sensitive than glycogenolysis to increments in plasma epinephrine.

Adult↗
PubMed1979

The effects of the concentration and function of hemoglobin on the survival of rats after hemorrhage.

Hemodilutional techniques of resuscitation, which are becoming popular, add anemia to the acute increase in the affinity of hemoglobin for oxygen that occurs in massively transfused patients when old liquid stored blood is used. A model simulating these conditions was established in rats, using blood stored in citrate for different durations ("fresh" for 1 day, P50 of 34.5 torr, and "old" for 14 to 20 days, P50 of 23.5 torr). Animals were exchange transfused of 90% of the original red cell mass with fresh or old blood at one of three different hematocrits, then hemorrhaged and treated with the same blood used for exchange. There was little difference in survival throughout the range of hematocrits when fresh blood was used (10 of 17, 11 of 16, and 10 of 16 rats). Survival was significantly less in recipients of old blood at low hematocrits (five of 21), but not at higher hematocrits (nine of 19, eight of 14). Ability to salvage the most vulnerable subgroup was tested in rats exchange transfused with old blood at low hematocrits, hemorrhaged, and treated with fresh or old blood, each at low or high hematocrits. Again survival was comparable with fresh blood at low or high hematocrits and old blood at high hematocrits (15 of 20, 19 of 21, 18 of 25) but was lower with old blood at low hematocrits (12 of 24). These results indicate that the oxygen-delivering capacity of blood can become a limiting factor in promoting survival after hemorrhage in otherwise normal animals when it is reduced below half of normal by a combination of anemia and impaired function of hemoglobin. Above that level, fresh blood was more efficacious than old blood in this model.

Anemia↗
PubMed1978

The relationship between transfusion and hypoxemia in combat casualties.

The relationship between transfusion and subsequent hypoxemia was examined retrospectively in the records of combat casualties studied by the first three U.S. Army Surgical Research Teams in Vietnam. There was no evident relationship in 425 casualties studied before anesthesia and operation. In 199 casualties studied preoperatively and on at least two of the first three postoperative days, there was no evident relationship in those with injuries not involving the chest or abdomen. Eighteen such casualties received over ten units of blood each (average 24.5) and exhibited subsequent changes in arterial oxygen tension (PaO2) which were indistinguishable from those transfused lesser amounts or not all. Similar observations were made in casualties with injuries to the abdomen, although there was a tendency to lower PaO2 two days after injury in those heavily transfused. In those with thoracic injury, there was statistically significantly lower PaO2 on the first two postoperative days in those heavily transfused. Two possible interpretations are considered, one that blood transfusion contributed to hypoxemia, and alternatively, that a greater magnitude of the injuries accounted for both the worsened hypoxemia and the need for more transfusions. The latter was thought more likely. The differences in PaO2 related to the type of injury exceeded the differences associated with transfusion.

Adult↗
PubMed1977

Surgical management of carcinoma of the cervix.

Three hundred and fifty-two cases of carcinoma of the cervix which required some surgical procedure are reviewed. In Group I (primary treated), the lymph nodes were positive in 9% with Stage I and 45% with Staqe II disease. This group had an 88% five-year survival rate; patients with positive lymph nodes had a 60% two-year survival rate. One or more surgical complications occurred in 16.5% of patients treated for recurrent disease. The five-year survival rate in patients treated for recurrent disease was 35%. The Schauta-Amreich procedure is being used more commonly for poor-risk patients with recurrent disease confined to the cervix or with superficial vaginal involvement.

Female↗