Availability of 11-cis retinal and opsins without chromophore as revealed by small bleaches of rhodopsin in excised albino mouse eyes

Small bleaches were used to study the rhodopsin regeneration process. At bleaches from 5.2% to 24.7%, the rhodopsin regenerations were consistent with a one-for-one recovery of bleached molecules. At response saturation rod photoreceptors exhibit a bleach level of only 5%. Major increases in rhodopsin regeneration were observed at bleach levels between 1.3% and 5.2%. The rhodopsin regenerations exhibited a linear relationship that was 4-times the bleach (dark adaptations of 0.75 and 1.5 h). The data show that the bleach initiates the availability, and possibly production, of 11-cis retinal in amounts that are 4-times the number of bleached molecules within the functional range of the rod photoreceptors. Rhodopsin regeneration also requires the presence of opsins without chromophore. Regenerations beyond the bleach indicate the presence of such opsins prior to the bleach. The opsin amounts were 8.1%, 8.6%, 3.1% and 0% of the total visual pigment at dark adaptation times of 0.75, 1.5, 24 and 48 h, respectively. Those opsins, as well as the ones produced by the bleach, may be regenerated to rhodopsin following a small bleach or with additional time in the dark.     

Serum profiles of insulin-like growth factors and their binding proteins in adults with growth hormone receptor deficiency treated with insulin like growth factor I

Six adult patients with growth hormone receptor deficiency (GHRD) (2 men, 4 women) with an identical defect in the growth hormone receptor (GHR) gene, were treated with recombinant human insulin-like growth factor I (IGF-I), 40 μgikg S.C. twice daily, for 7 days. Serum concentrations of IGF peptide and IGF binding protein-3 (IGFBP-3) were measured by specific radioimmunoassays; serum IGFBPs were also measured by Western ligand blotting. The size distribution of both IGF-I and IGF-II was measured in serum following size-exclusion fast-performance liquid chromatography. IGF-I treatment resulted in a normalization of serum IGF-I levels on days 1–7 of treatment and a decrease in serum IGF-II levels. The fall in IGF-II levels and the simultaneous rise in IGF-I levels, however, resulted in an unchanged total serum IGF level. The low IGFBP-3 values did not significantly change during treatment, whereas there was a slight increase in IGFBP-2 levels. Preliminary analysis of size-fractionated sera suggested an increase in IGF-I levels in the 40 and 150 kDa regions at the expense of IGF-II levels. The results suggest that despite the failure of IGF-I treatment to increase IGFBPs significantly, serum IGFBP concentrations were sufficient to maintain normal levels of IGF-I. 0 Laron syndrome, growth hormone receptor deficiency, insulin-like growth factors, insulin-like growth factor binding protein     

The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity

The integrity of sperm DNA is crucial for the maintenance of genetic health. A major source of damage is reactive oxygen species (ROS) generation; therefore, antioxidants may afford protection to sperm DNA. The objectives of the study were, first, to measure the effects of antioxidant supplementation in vitro on endogenous DNA damage in spermatozoa using the single cell gel electrophoresis (comet) assay and, second, to assess the effect of antioxidant supplementation given prior to X-ray irradiation on induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll centrifugation in the presence of ascorbic acid (300, 600 microM), alpha tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5, 10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand breakage was measured using the comet assay. Sperm DNA was protected from DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60 microM) and urate (400 microM). These antioxidants provided protection from subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or ascorbate and alpha tocopherol together induced further DNA damage. Supplementation in vitro with the antioxidants ascorbate, urate and alpha tocopherol separately has beneficial effects for sperm DNA integrity.      

氯沙坦减少高血压患者终点事件的研究(LIFE STUDY)

标　　题　应用ＡＴⅡ受体拮抗剂抗高血压治疗作　　者　ＫｊｅｌｄｓｅｎＳＥ,ＯｍｖｉｋＰ.　　参考文献　ＴｉｄｓｓｋｒＮｏｒＬａｅｇｅｆｏｒｅｎ,1996,116:504～507研究疾病　高血压病。目　　的　评估氯沙坦对心血管死亡率及非致死性心肌梗死和非脑卒中发生率的影响,同时评估该药对充血性心力衰竭或心绞痛所致的总死亡率和住院率的影响,以及长期应用氯沙坦对发生新诊断糖尿病的影响。设　　计　随机、三盲、对照研究。病人资料　8300例年龄55～80岁、收缩压在160～200ｍｍＨｇ、舒张压在95～115ｍｍＨｇ的高血压患者,ＥＣＧ上有左室…