Nitric oxide and thermogenic function of brown adipose tissue in rats

To clarify the effects of cold acclimation and immobilization stress adaptation of rats on nitric oxide (NO) activity in interscapular brown adipose tissue (BAT), we incubated neatly diced (1-mm(3) blocks) BAT in a metabolic chamber for respiration, measured oxygen consumption using a Clark electrode, and estimated NO release in the buffer medium by measuring nitrite plus nitrate (NO(x)) using the Griess method (diazotization reaction). The production of NO(x) in the buffer medium confirmed that BAT releases NO, as there is no other source of NO(x) in the system. The NO activity was observed in the basal condition and increased with noradrenaline stimulation, showing a correlation with oxygen consumption in the warm (25 degrees C)-acclimated control rats. Cold acclimation (5 degrees C, 5 weeks) or immobilization stress adaptation (3 h daily, 25 degrees C, 5 weeks) caused enhanced NO activity in the basal condition in comparison with the control. We suggest that NO is involved in enhancement of the thermogenic functions of BAT in rats.     

Serotypes of Streptococcus pneumoniae causing invasive childhood infections in Bangladesh, 1992 to 1995.

One hundred sixty-five invasive Streptococcus pneumoniae strains were isolated from children under five at Dhaka Shishu (Children's) Hospital during the period 1992 to 1995. Ninety-four strains were from cerebrospinal fluid, and 71 were from blood. More than 91% of the strains were isolated from patients aged 24 months or less. Predominant serotypes were, in descending order 7F, 12F, 14, 15B, 18, 5, and 22A. These comprised 70% of all isolates. The marked differences in serotype distribution in different countries indicate the need for a sentinel surveillance study for the countries of South Asia, particularly Bangladesh, China, India, and Pakistan.     

Teaching systems-based practice to residents by using independent study projects.

The changing health care marketplace requires new graduates to be familiar with complex health systems. Since 1999 the Oregon Health & Science University internal medicine residency program has offered a seminar-based health systems curriculum, but residents lacked an opportunity to actively apply learned concepts. To achieve this goal, the authors developed a second curricular component, the Health Systems Independent Study Project (HSISP). The HSISP is a self-directed assessment of a health care system or delivery issue residents complete in their third year. The curriculum was implemented in 2001 with goals of gaining a focused understanding of a health systems concept and building related skills. Residents present their study projects to all curriculum participants. Topics addressed so far include adherence to coronary artery disease guidelines in a defined population, screening strategies for lung cancer, resident burnout, and many others. Residents have found that these projects enhance their systems knowledge, help them link systems-based-practice concepts to clinical practice, and foster opportunities for networking and early career development.     

Influence of serum paraoxonase polymorphism on serum lipids and apolipoproteins

One hundred and sixty-three healthy Chinese subjects of both sexes were studied for serum paraoxonase (PON) polymorphism, and levels of lipids and apolipoproteins in order to examine effects of PON alleles on these parameters. The level of serum triglyceride was significantly higher in high activity allele (PON*B) compared with that in low activity allele (PON*A) in both sexes (P less than 0.01). The subjects with PON A had significantly higher LDL cholesterol (P less than 0.05) and lower Apo A-II and ApoB levels. The influence of serum paraoxonase on serum lipids was estimated further by Spearman's rank correlation. In the males, there was a significant negative correlation of serum paraoxonase activity with total (P less than 0.05) and LDL (P less than 0.01) cholesterol levels, and positive correlation with HDL cholesterol and Apo A-II levels (P less than 0.05). Serum paraoxonase activity had a high positive correlation with serum triglyceride levels in both sexes (P less than 0.001). Serum ApoB level had a positive correlation with the enzyme activity only in females (P less than 0.01). The allelic effect of PON on these parameters was studied by multiple regression analysis. The high activity allele (PON*B) was associated with higher serum triglyceride level (P less than 0.001) and ApoB (P less than 0.001), while it had lowering influence on total cholesterol (P less than 0.05) and LDL cholesterol (P less than 0.005) in men. The average allelic effect of PON was found to be about 22% for serum triglycerides, 11% for LDL cholesterol, 14% for Apo A-II and 19% for Apo B in the present study. This study suggests a possible significant role of serum paraoxonase alleles in the metabolism of serum lipids and apolipoproteins.     

Evaluation of three simple and rapid immunological tests for detection of heat-labile enterotoxin of enterotoxigenic Escherichia coli.

Three simple immunological tests, the modified Elek (Biken) test, the modified staphylococcal coagglutination test, and the rapid GM1-horseradish peroxidase-enzyme-linked immunosorbent assay have been evaluated for detection of heat-labile enterotoxin of enterotoxigenic Escherichia coli. Of the 100 coded E. coli strains tested, 94 gave consistent results with all the three immunological tests; a discrepancy was observed in only 6 strains. Identical results were obtained when the Biken test was conducted with complete and incomplete Biken kits (Meguro Institute Ltd., Osaka, Japan). All three immunological tests evaluated in this study were found to be sensitive and simple and can be easily adopted by any laboratory for detection of heat-labile enterotoxins of enterotoxigenic E. coli strains.     

Rapid identification and antibiotic susceptibility testing of Salmonella enterica serovar Typhi isolated from blood: implications for therapy

The turnaround time (TAT) for Salmonella enterica serovar Typhi identification and reporting of the antibiotic susceptibility profile was determined for 391 cases of typhoid fever, using the lysis direct plating or lysis centrifugation method of blood culture along with rapid antimicrobial susceptibility testing. The TAT was more rapid (TAT for 90% of the patients [TAT(90)] = 30 h; TAT(100) 相似文献   

The trypanosome alternative oxidase exists as a monomer in Trypanosoma brucei mitochondria

The bloodstream forms of African trypanosomes solely depend on trypanosome alternative oxidase (TAO), for respiration. Similar to alternative oxidases (AOXs) found in plants and fungi, TAO is a membrane-bound diiron protein. Here, we investigated if TAO exists as a dimer like plant AOXs, or as a monomer like that of fungi. We have found that TAO forms a homo-dimer on a regular SDS-PAGE in the absence of any reducing agent and exists as a monomer under reducing condition. However, TAO does not form a dimer upon treatment of mitochondria with diamide. TAO was found as a higher molecular mass complex on a Blue-native gel after solubilization with digitonin. In the detergent soluble form, TAO activity was stimulated under reducing and inhibited under oxidizing condition. However, these conditions have no effect on the TAO activity in the mitochondria. Moreover, chemical cross-linking analysis revealed that TAO could not be cross-linked when present in the mitochondria. Together, it suggests that like certain other hydrophobic membrane proteins, TAO forms a dimer or oligomer when solubilized with detergents, and the TAO-dimer is SDS-resistant. However, it exists as a monomer in Trypanosoma brucei mitochondria.     

The E3-11.6K protein of adenovirus is an Asn-glycosylated integral membrane protein that localizes to the nuclear membrane.

The 11,600 MW (101 amino acids; 11.6K) protein of adenovirus 2 (Ad2) is a protein of unknown function which is synthesized in low amounts during early stages of infection but in very high amounts at late stages. The 11.6K protein migrates as three major groupings of diffuse bands of ca. 14K, 21K, and 31K on SDS-PAGE, indicating that 11.6K undergoes post-translational modification. We show here that 11.6K is Asn-glycosylated with complex (endo H-resistant) oligosaccharides and that 11.6K is an integral membrane protein. Immunofluorescence indicated that 11.6K initially is associated with the endoplasmic reticulum and Golgi apparatus and that it ultimately localizes to the nuclear membrane. The 11.6K protein is predicted to have a single signal-anchor sequence at residues 41-62 and only one potential Asn-linked glycosylation site at residue 14; thus, 11.6K must be oriented in the membranes with its NH2-terminus in the lumen and its COOH-terminus in the cytoplasm. The signal-anchor and glycosylation features of 11.6K are preserved in Ad2 and Ad5 (group C), and in Ad3 and Ad7 (group B), but the sequence of 11.6K is more diverged among these serotypes than is the sequence of most other adenovirus proteins.     

Adverse effects of early dexamethasone in extremely-low-birth-weight infants. National Institute of Child Health and Human Development Neonatal Research Network

BACKGROUND: Early administration of high doses of dexamethasone may reduce the risk of chronic lung disease in premature infants but can cause complications. Whether moderate doses would be as effective but safer is not known. METHODS: We randomly assigned 220 infants with a birth weight of 501 to 1000 g who were treated with mechanical ventilation within 12 hours after birth to receive dexamethasone or placebo with either routine ventilatory support or permissive hypercapnia. The dexamethasone was administered within 24 hours after birth at a dose of 0.15 mg per kilogram of body weight per day for three days, followed by a tapering of the dose over a period of seven days. The primary outcome was death or chronic lung disease at 36 weeks' postmenstrual age. RESULTS: The relative risk of death or chronic lung disease in the dexamethasone-treated infants, as compared with those who received placebo, was 0.9 (95 percent confidence interval, 0.8 to 1.1). Since the effect of dexamethasone treatment did not vary according to the ventilatory approach, the two dexamethasone groups and the two placebo groups were combined. The infants in the dexamethasone group were less likely than those in the placebo group to be receiving oxygen supplementation 28 days after birth (P=0.004) or open-label dexamethasone (P=0.01), were more likely to have hypertension (P<0.001), and were more likely to be receiving insulin treatment for hyperglycemia (P=0.02). During the first 14 days, spontaneous gastrointestinal perforation occurred in a larger proportion of infants in the dexamethasone group (13 percent, vs. 4 percent in the placebo group; P=0.02). The dexamethasone-treated infants had a lower weight (P=0.02) and a smaller head circumference (P=0.04) at 36 weeks' postmenstrual age. CONCLUSIONS: In preterm infants, early administration of dexamethasone at a moderate dose has no effect on death or chronic lung disease and is associated with gastrointestinal perforation and decreased growth.