Studies on avian erythrocyte metabolism. VII. Effect of inositol pentaphosphate and other organic phosphates on oxygen affinity of the embryonic and adult-type hemoglobins of the turkey embryo.

The effects of 2, 3-diphosphoglyceric acid (2, 3-DPG), adenosine triphosphate (ATP), inositol tetraphosphate (ITP), inositol pentaphosphate (IPP), and inositol hexaphosphate (IHP) on oxygen affinity of whole stripped hemoglobin (WSH), hemoglobin H (Hb-H; hatching hemoglobin), hemoglobin A (Hb-A), and hemoglobin D (Hb-D) isolated from erythrocytes (RBC) of the 25-day turkey embryo have been studied. The order of the decrease in oxygen affinity induced by these organic phosphates, at molar ratios of phosphate compound to hemoglobin (tetramer) between 2 and 4, is 2, 3-DPG less than ATP less than ITP less than IPP less than IHP. 2, 3-DPG shows a slightly greater effect on reducing oxygen affinity of Hb-H than on either adult-type hemoglobin. The effect of IPP upon lowering the oxygen affinity of either WSH, Hb-H, Hb-A, or Hb-D is approximately 20 percent less than IHP. The effects of the various organic phosphates upon the Hill constant, n, of these purified hemoglobins is variable but appears to reach a maximum when the molar ratio of organic phosphate to hemoglobin (tetramer) is 2 or greater. None of the physiologically occurring organic phosphates has a significant preferential interaction with any specific hemoglobin. These experiments strengthen and support our earlier conclusion, that the changes in whole blood oxygen affinity which occur during avian development result from the changes in composition of the intraerythrocytic organic phosphates.     

Low levels of 25-hydroxy vitamin D are associated with elevated parathyroid hormone in healthy adolescent females

This study aimed to investigate the relationship between 25-hydroxyvitamin D [25(OH)D)] and parathyroid hormone (PTH) levels in adolescent females residing in a northern climate. Concern regarding vitamin D status in this population is due to limited sunlight exposure in northern latitudes, decreased outdoor recreational activities, as well as decreased conversion in black girls from increased skin pigmentation. In this cross-sectional analysis, serum samples were assayed for 25(OH)D using competitive protein binding (CPB) assay and PTH with immuno-radiometric (RIA) procedures. Four hundred postmenarcheal females (12–18 years) residing in northeastern Ohio were recruited. Subjects were excluded if they had a history of bone, kidney, or liver disease, or used medications that affect bone. The primary goal was to determine serum 25(OH)D concentrations in relation to circulating PTH levels in a population of adolescent girls. The Spearman correlation test was used to compare PTH and 25(OH)D. Fit multiple split models were run to determine change in slope of the regression line when 25(OH)D and PTH were plotted. Analysis of variance was determined using modeled means with differences by race and season in the final model. Unadjusted mean serum 25(OH)D and PTH levels were 55.0±30.4 nmol/l and 39.4±20.6 ng/l, respectively. Blacks had lower 25(OH)D and higher PTH compared with non-blacks (P<0.0001), especially during the winter months. Decreasing 25(OH)D was inversely correlated with PTH (r=–0.314) (P<0.0001), and at concentrations of 25(OH)D 90 nmol/l, an increase in PTH was observed. Adolescents are at risk for decreased serum 25(OH)D concentrations, especially black girls. We found that the widely used cutoff for vitamin D deficiency is associated with increasing PTH levels and is below the inflection point for a change in the slope of the regression line. Our results support the need for further research to establish optimal vitamin D status in adolescent girls.     

Endometrial carcinoma—endocrinological and clinical studies

Hormone assay studies in urine together with clinical and cytological observations have been performed in 8 patients with endometrial carcinoma, all of whom were treated by hysterectomy and bilateral salpingo-oophorectomy. In one woman with vaginal metastasis from a previous endometrial carcinoma similar studies were made before and after radium implantation.In all subjects prior to operation estrogen levels were within the normal range for postmenopausal women. In spite of this finding only one patient had an atrophic vaginal smear, the remainder showing abnormally high cornification indices. It is, therefore, suggested that cytological evidence provides and unreliable index of estrogenic activity in patients with endometrial carcinoma.No relationship between hilar cell hyperplasia and cortical stromal hyperplasia on the one hand and urinary estrogen output on the other could be demonstrated.Following operation adrenocortical stimulation as judged by assays of estrogens, 17-hydroxycorticosteroids, and 17-oxosteroids was observed in four out of the 6 patients studied. In none of the subjects were urinary HPG levels above the range normally found in postmenopausal women. The effect of operation on HPG excretion showed no consistent pattern.     

Effect of a postoperative telephone intervention on attendance at intake for cardiac rehabilitation after coronary artery bypass graft surgery

BACKGROUND: Enrollment in cardiac rehabilitation (CR) after coronary artery bypass graft (CABG) surgery is suboptimal (25%-30%). OBJECTIVES: The purpose of this study was to examine the effect of a nurse-initiated telephone call (NIC) on attendance at a CR intake appointment. METHODS: By using a retrospective cohort design, data were collected on 3536 patients who underwent CABG between April 1996 and March 2000 and were referred to CR. Of these, 2285 patients received standard care (no NIC) and 1251 received the NIC. RESULTS: Patients who received the NIC were significantly more likely to attend their CR intake appointment compared with standard care (78.1% vs. 50.1%; P < .0001). Hierarchic logistic regression analysis revealed the NIC as the strongest predictor of attendance at a CR intake explaining 56.9% of the total variance (odds ratio =3.429; 95% confidence interval = 2.919-4.028; P < .0001). CONCLUSION: These findings suggest that pre-appointment telephone contact by a cardiovascular nurse is a valuable tool to enhance attendance at a CR intake appointment after CABG.