Novel angiotensin peptides regulate blood pressure, endothelial function, and natriuresis

Accumulating evidence suggests that angiotensin-(1-7) is an important component of the renin-angiotensin system, having actions that are either identical to or opposite that of angiotensin II. Angiotensin I can be directly converted to angiotensin-(1-7), bypassing formation of angiotensin II. This pathway is under the control of three enzymes: neutral endopeptidases 24.11 (neprilysin) and 24.15 and prolyl-endopeptidase 24.26. Two of the three angiotensin-forming enzymes (neprilysin and endopeptidase 24.15) also contribute to the breakdown of bradykinin and the atrial natriuretic peptide. Furthermore, angiotensin-(1-7) is a major substrate for angiotensin-converting enzyme. These observations suggest that the process of biotransformation between the various Ang peptides of the renin-angiotensin system and other vasodepressor peptides are intertwined through this enzymatic pathway. Substantial evidence suggests that angiotensin-(1-7) stimulates the synthesis and release of vasodilator prostaglandins, and nitric oxide, while also augmenting the metabolic actions of bradykinin. In addition, angiotensin-(1-7) alters tubular sodium and bicarbonate reabsorption, decreases Na+-K+-ATPase activity, induces diuresis, and exerts a vasodilator effect. These physiologic effects of angiotensin-(1-7) favor a blood pressure-lowering effect. The majority of the data currently available suggest that angiotensin-(1-7) mediates its effects through a novel non-AT1/AT2 receptor subtype.     

Evolution of the nutritional support pattern in pediatric intensive care

OBJECTIVES: To evaluate patterns of usage and monitoring of nutritional support in a Pediatric ICU of a teaching hospital and the role of an education program in nutritional support given throughout the resident physician training. DESIGN: In a historical cohort study, records from children who received nutritional support during the year 1992 were analyzed. Thereafter a continuing education program in Nutritional Support was conveyed to the residents. In a second phase of the study, the same parameters were reevaluated in children who received nutritional support throughout the year 1995. SETTING: Pediatric Intensive Care Unit of Department of Pediatrics, Escola Paulista de Medicina. PATIENTS: All the children who were given nutritional support during a period of five days or more. Based on this criteria 37 children were selected for the first phase of this study, and 35 for the second one. INTERVENTION: The education program included theoretical lectures about basic themes of nutritional support and journal article reading sessions. It was given to successive groups of residents on a weekly schedule. MEASUREMENTS: Daily records of fluid, protein, caloric and micronutrient supply, nutritional assessment and metabolic monitoring. RESULTS: In the first phase of the study, an exclusively parenteral route was utilized for 80.5%, and a digestive route 19.5% of the time period. Nutritional assessment was performed on 3 children; no patient had the nutritional goals set. The nitrogen to nonprotein calories ratio and the vitamin supply were inadequate, whilst the supply of trace elements was adequate except for zinc. Nutritional monitoring was performed on almost all patients but without uniformity. In the second phase, the exclusive parenteral route was used for 69.7% and the digestive route for 30.3% of the time period; no significant increase in the use of the digestive route was detected. The nonprotein calories to nitrogen ratio and micronutrient supply were adequate. The frequency of nutritional assessment increased, but deficiency in nutritional monitoring and infrequent enteral feeding were still detected. CONCLUSION: There were deficiencies in the implementation of nutritional support, which were partially corrected in the second phase of the study by the training of the residents. Reinforcement of the education program, which should be applied to the whole medical staff, and the organization of a multidisciplinary team in charge of coordinating the provision of nutritional support are suggested.     

Hyperglycemia induces apoptosis in pre-implantation embryos through cell death effector pathways

Although perinatal mortality rates have improved for pregnant diabetic women because of insulin therapy and tight metabolic control, infants of diabetics still experience significantly higher rates of congenital malformations and spontaneous miscarriages compared with those of non-diabetic women. Our results here indicate that hyperglycemic conditions, either in vivo or in vitro, modulate the expression of an apoptosis regulatory gene as early as the pre-implantation blastocyst stage in the mouse. Apoptosis in the mammalian pre-implantation blastocyst is a normal process, thought to protect the early embryo by eliminating abnormal cells. Here we demonstrate that expression of Bax, a Bcl-2-like protein, is increased at the blastocyst stage in the presence of high concentrations of glucose, and that these changes correlate morphologically with increased DNA fragmentation. Expression of Bax and caspase are necessary for this in vitro glucose-induced apoptotic event, and ceramide is involved in mediating this embryotoxic effect of glucose. We also show that these apoptotic cellular changes can be prevented in vivo by treating hyperglycemic mice with insulin before and immediately after conception. These findings emphasize the importance of tight glycemic control in diabetic women at the earliest stages after conception.     

Detection of cytomegalovirus in plasma and cerebrospinal fluid specimens from human immunodeficiency virus-infected patients by the AMPLICOR CMV test

We have developed the AMPLICOR CMV Test, which is rapid and sensitive for the detection of cytomegalovirus (CMV) in plasma and cerebrospinal fluid (CSF) specimens. The test incorporated an internal control in the reaction mixture to monitor the amplification efficiency and the presence of inhibitors. The AMPLICOR CMV Test was very specific in detecting 12 clinical CMV isolates and four laboratory CMV strains tested. Cross-reactivity with 26 non-CMV pathogens was not observed. The AMPLICOR CMV Test requires only 50 microl of specimen (plasma or CSF) for processing. The performance of the AMPLICOR CMV Test was compared to those of the CMV antigenemia assay and the conventional tube culture method. Among 112 plasma specimens from 43 human immunodeficiency virus-infected patients, CMV was detected in 20 (18%) of the specimens by the AMPLICOR CMV Test, 21 (19%) of the specimens by the CMV antigenemia assay, and 10 (9%) of the specimens by culture. In CSF specimens from AIDS patients, CMV was detected in 10 of 58 (17%) specimens tested by the AMPLICOR CMV Test, 5 of 28 (18%) specimens tested by the antigen assay, and none of the 25 specimens tested by culture. While the performance of the AMPLICOR CMV Test in this study was comparable to that of the CMV antigen assay, processing of specimens by the AMPLICOR CMV Test was much simpler than that by the antigen assay; in addition, the antigen assay requires greater than 10(5) leukocytes from blood or 1 ml of CSF to perform the assay. Our study suggested that the AMPLICOR CMV Test could provide a rapid and sensitive assay for the detection of CMV in plasma and CSF specimens.     

家庭与Soho的好选择—Lexmark X73多功能一体机

有没有试过这样的情况？资料拿去扫描，图片又要打印，还有一份文件要传真给人家，这时，你大概就会领悟到什么是疲于奔命了。如果你有上述的苦恼，而且局限于空间或者财力上的不足，无法一次性的购买复印机、传真机、彩色打印机等设备的话，那你或许有兴趣看看利盟（Ｌｅｘｍａｒｋ）这款新推出的Ｘ７３多功能一体机。简洁流线的造型　Ｌｅｘｍａｒｋ　Ｘ７３虽然集成了多种功能，但是体形却不笨重，搬动起来也不费劲，银灰色的外壳加上流线式的造型给人的感觉十分稳重大方。在机壳盖的旁边，有几组按钮，有关的复印（包括打印）、扫描等…     

5-HT1-like receptors: a time to bid goodbye

It is exactly half a century ago that 5-hydroxytryptamine was discovered and over four decades ago two types of 5-HT receptors were described. In this article, Pramod Saxena, Peter De Vries and Carlos Villalón trace the development of the modern classification and nomenclature of 5-HT receptors, which now include more than a dozen subtypes. In doing so, they advocate that the so-called '5-HT1-like' receptors, having been shown to be a heterogeneous population of 5-HT1B, 5-HT1D and 5-HT7 receptors, are now redundant.     

Special properties of living tissue that affect the shoulder in athletes

The physiologic function of the structures of the shoulder is to withstand the forces that arise from activity without sustaining injury. From our understanding of the biology of these tissues, we can see how they modify themselves to prevent injury and react, appropriately or inappropriately, to injury. This information, and knowledge yet to be discovered in the laboratory, should lead to more effective surgery, physical therapy, and use of medication.     

Direct cloning of human parathyroid hyperplasia cells in soft-agar culture

Parathyroid specimens removed from patients with clinical hyperparathyroidism were cultured in a two-layer soft-agar system. Four patients had parathyroid hyperplasia and one had a parathyroid adenoma. Colonies grew from single-cell suspensions of each specimen. Plating efficiency ranged from 0.001 to 0.05%. No colonies grew from normal bovine parathyroid specimens. Parathormone was detected in 0.9% NaCl solution incubated with the culture plates of three of the four human specimens tested. Parathormone levels determined by radioimmunoassay ranged from 10.4 < 100 ng/ml. Plates tested serially showed a progressive rise in parathormone levels with time and an increase in colony size and number. Microscopic evaluation of the cellular layer showed clusters of cells morphologically consistent with parathyroid origin. Colonies remained viable for approximately 3 weeks. These data confirm that malignancy of tissue in vivo is not necessary for colony formation in agar and that human parathyroid hyperplasia or adenoma cells produce and secrete parathormone in this system.