1，4-环己二酮单乙二醇缩酮的合成研究

对1,4-环已二酮的单保护反应进行了研究,在自制催化荆催化下,用n(乙二醇)∶n(1,4-环己二酮)=1∶1进行脱水缩合反应,在环己烷溶液中除去部分未保护的原料,在乙酸乙酯中用亚硫酸氢钠提取单保护产物,用10%的碳酸钠脱去亚硫酸氢钠,结晶精制而得产品1,4-环己二酮单乙二醇缩酮[1,4-二氧杂螺(4,5)癸烷-8-酮],收率为68.2%,气相色谱测定其纯度为99.8%.     

Transport is the primary determinant of glycine content in retinal neurons

This study demonstrates that in mammalian and nonmammalian species it is possible to deplete selectively and reversibly retinal glycinergic neurons of their content of glycine by exposure to sarcosine, a competitive inhibitor of glycine transporter 1 (glyt-1). This observation was used as a tool to test the hypothesis that uptake of glycine rather than de novo synthesis is the main determinant of glycine content in retinal neurons. Isolated retinae were depleted of immunocytochemically detectable pools of glycine. Thereafter retinae were exposed either to physiological medium containing glycine or to medium lacking glycine but containing precursors for the synthesis of glycine. Retinae exposed to glycine-containing medium rapidly recovered their content of glycine, whereas retinae exposed to medium lacking glycine but containing serine, a substrate for synthesis of glycine, showed only a slow recovery of immunoreactivity for glycine in a few amacrine cells. These data indicate that uptake of glycine is the primary determinant of glycine content in most retinal glycinergic neurons. The origins of the extracellular pools of glycine remain to be identified; however, it is suggested that such glycine may be derived from the vitreous humor and that in turn this glycine may be derived from the peripheral circulation.     

Effects of age, system experience, and navigation technique on driving with an advanced traveler information system

This paper explores the effects of age, system experience, and navigation technique on driving, navigation performance, and safety for drivers who used TravTek, an Advanced Traveler Information System. The first two studies investigated various route guidance configurations on the road in a specially equipped instrumented vehicle with an experimenter present. The third was a naturalistic quasi-experimental field study that collected data unobtrusively from more than 1200 TravTek rental car drivers with no in-vehicle experimenter. The results suggest that with increased experience, drivers become familiar with the system and develop strategies for substantially more efficient and safer use. The results also showed that drivers over age 65 had difficulty driving and navigating concurrently. They compensated by driving slowly and more cautiously. Despite this increased caution, older drivers made more safety-related errors than did younger drivers. The results also showed that older drivers benefited substantially from a well-designed ATIS driver interface.     

Evaluation of high-resolution CT and MR cisternography in the diagnosis of cerebrospinal fluid fistula

BACKGROUND & AIMS: Whether inflammation of the cardia indicates gastroesophageal reflux disease (GERD) and/or is a manifestation of pangastritis caused by Helicobacter pylori infection is unknown. The aim of this study was to evaluate the relationship between cardia inflammation, H. pylori infection, and cardia intestinal metaplasia in patients with and without GERD. METHODS: Patients with GERD were compared with controls undergoing endoscopy for a variety of other conditions. Endoscopic biopsy specimens from the distal esophagus and cardia, fundus, and antrum were evaluated for inflammation, H. pylori infection, and intestinal metaplasia. RESULTS: Neither the prevalence of H. pylori infection (controls, 48%; GERD, 41%) nor cardia inflammation (controls, 41%; GERD, 40%) differed between groups. All 11 controls and 22 of 23 patients with GERD (96%) and cardia inflammation had H. pylori infection. Esophagitis was more common among GERD patients (33%) than controls (7%; P = 0.01). Cardia intestinal metaplasia was more common among controls (22%) than GERD patients (3%; P = 0.01); all had cardia inflammation, 7 had H. pylori infection, and 6 had metaplasia elsewhere in the stomach. CONCLUSIONS: The prevalence of cardia inflammation is similar in patients with and without GERD and is associated with H. pylori infection (P < 0.001). Cardia intestinal metaplasia is associated with H. pylori-related cardia inflammation (P = 0.01) and intestinal metaplasia elsewhere in the stomach, indicating that it is distinct from Barrett's esophagus.     

Stomach implant for long-term erythropoietin expression in rats

Caveolae are small microdomains of the plasma membrane that are thought to play important roles in signal transduction processes. In this work, we have investigated the association of Rho proteins with caveolae-enriched membrane domains isolated from cultured endothelial cells. Fractionation of ECV304 cells by sucrose gradient density centrifugation in the absence of detergent resulted in the co-sedimentation of a significant proportion of RhoA and Cdc42 with known caveolae marker proteins, including caveolin, but not with other non-caveolae membrane proteins such as the angiotensin-converting enzyme. Immunoprecipitation experiments carried on crude endothelial cell lysates as well as with solubilized caveolae-enriched membrane domains showed the coimmunoprecipitation of caveolin with RhoA but not with Cdc42. Incubation of endothelial cell lysates with a glutathione-S-transferase (GST)-RhoA fusion protein resulted in the specific precipitation of caveolin, while addition of GST-caveolin-1 to the lysates promoted the precipitation of RhoA. Moreover, incubation of bacterially expressed RhoA with GST-caveolin-1 resulted in the precipitation of RhoA, indicating that RhoA directly interacts with caveolin-1. This interaction was found to be nucleotide-independent and was not affected by prior modification of RhoA with the C3 exoenzyme from C. botulinium or with the cytotoxic necrotinizing factor from E. coli. Taken together, these results suggest the association of RhoA with endothelial caveolae-enriched membrane domains, likely through physical interaction with caveolin-1. These findings may provide new insights into the functions played by Rho proteins and caveolae in signal transduction events.     

Specific glucocorticoid binding at different levels of human motor activity

We studied the number of glucocorticoid receptors and dissociation constant in isolated human lymphocytes as well as blood concentrations of hormones produced by the hypothalamic-hypophyseal-adrenocortical system in three experimental series: at normal (17 subjects), decreased (10 subjects, a 360-d head-down bed rest) and increased (8 subjects, physical exercise on bicycle ergometer) levels of motor activity. In the first series we found that the number of glucocorticoid receptors and dissociation constant did not depend on the season, on the age of subjects nor on cortisol concentrations in blood. In the second series we observed the following: at the end of the first month of bed rest the number of glucocorticoid receptors and receptor affinity significantly increased; at the beginning of the third month of bed rest specific glucocorticoid binding significantly decreased and circadian rhythms of adrenocorticotropin and cortisol in blood varied markedly; at the end of the sixth month of bed rest the number of glucocorticoid receptors returned to prebed rest levels and dissociation constant decreased. In the third series physical exercises that induced an activation of the hypothalamic-hypophyseal-adrenocortical system (maximal physical exercises and prolonged submaximal exercises at 70% of maximal oxygen uptake) led to a significant increase in the number of glucocorticoid receptors without changes of dissociation constant. These results indicate that both a decrease and an increase of human motor activity resulted in significant changes of specific glucocorticoid binding which were not influenced by changes of circulating hormone concentrations in blood but by some other factors affected by physical activity.