Optimizing Techniques for Determining Body Composition

<正> KEY POINTS  Accurate body composition assessments are vital to monitoring growth, training outcomes, health, and nutritional status of athletes.  Body composition assessment in athletes and other relies on non-invasive indirect methods that are based on theoretical models. Any errors in the theoretical models will produce errors in the indirect methods. performance.     

七氟醚预处理对体外循环冠状动脉旁路移植术病人围术期心肌的保护作用

目的探讨七氟醚预处理对体外循环(CPB)下冠状动脉旁路移植术(CABG)病人心肌的保护作用。方法择期CPB下CABG病人40例,ASAⅡ级或Ⅲ级,随机分为2组(n=20):七氟醚组(S组)或异丙酚组(P组)。麻醉维持:P组靶控输注异丙酚,血浆靶浓度2～3μg/L,静脉输注芬太尼2～3μg·kg~(-1)·h~(-1);S组夹闭主动脉前,吸入0.5%～2%七氟醚,静脉输注芬太尼2～3μg·kg~(-1)·h~(-1),夹闭主动脉后靶控输注异丙酚,血浆靶浓度2～3μg/L,静脉输注芬太尼2～3μg·kg~(-1)·h~(-1)。于切皮前即刻、CPB前即刻、CPB后即刻、回ICU后即刻、6、12h记录心率(HR)、平均动脉压(MAP)、肺动脉楔压(PCWP)、中心静脉压(CVP)、心脏指数(CI)、体循环血管阻力指数(SVRI)。于麻醉诱导前、回ICU后即刻、6、12、24h采集静脉血,测定血清心肌肌钙蛋白I(cTnI)浓度。记录术后不良事件的发生情况。结果2组各时点MAP、PCWP、CVP、HR和SVRI比较差异无统计学意义(P>0.05);与切皮前即刻和P组比较,S组回ICU后各时点CI升高(P<0.05)。与P组比较,S组回ICU后各时点cTnI浓度降低(P<0.05)。2组病人术后均无死亡;2组心肌梗塞、房颤和心肌缺血的发生率差异无统计学意义(P>0.05);S组cTnI浓度>2ng/ml的发生率低于P组(P<0.05)。结论七氟醚预处理对体外循环下冠状动脉旁路移植术病人围术期心肌具有一定的保护作用。     

Diagnosis of pneumococcal pneumonia by psaA PCR analysis of lung aspirates from adult patients in Kenya

psaA is the gene encoding pneumococcal surface adhesin A (PsaA), a 37-kDa protein expressed on the surface of Streptococcus pneumoniae. PCR primers for psaA have been shown to amplify the target DNA sequence in all 90 serotypes of S. pneumoniae and in none of 67 heterologous pathogens and colonizing bacteria of the upper respiratory tract. Pathogenic bacteria identified in lung aspirate specimens cannot normally be dismissed as contaminants or colonizers, which limit the assay specificity of other respiratory tract specimens. psaA PCR analysis was evaluated in 171 lung aspirates from Kenyan adults with acute pneumonia. The limit of detection was one genome equivalent. Sensitivity, estimated in 35 culture-positive lung aspirates, was 0.83 (95% confidence interval, 0.70 to 0.95). psaA PCR analysis extended the number of identifications of S. pneumoniae in lung aspirates from 35 on culture to 61 by both methods. Of 26 new pneumococcal diagnoses, 19 were corroborated by results of blood culture or urine antigen detection. Sequences of the PCR products from 12 positive samples were identical to the psaA target gene fragment. Using an internal control for the PCR, inhibition of psaA PCR was demonstrated in 17% (8 of 47) of false-negative specimens. The results of a control PCR for the human gene beta-actin suggested that false-negative psaA PCR results are attributable to problems of specimen collection, processing, or DNA extraction in 30% of cases (14 of 47). psaA PCR analysis is a sensitive tool for diagnosis of pneumococcal pneumonia in adults.     

Evidence for persistence of adenovirus in the tear film a decade following conjunctivitis

Chronic papillary conjunctivitis has been described following adenoviral conjunctivitis. It is unknown however, how long adenovirus is able to persist in the tear film and conjunctiva. To determine if adenovirus persists in the ocular surface following adenoviral conjunctivitis, 304 patients with a history of adenovirus conjunctivitis from whom an adenovirus had been isolated 10 years previously were sent a questionnaire regarding persistent or recurrent symptoms and were invited to attend. Patients were examined and samples of tears and conjunctival cells were collected from both eyes using tear film washes, filter paper, and swabs, the latter for virus isolation. Extracted DNA from the ocular samples was amplified using primers for herpes simplex virus (thymidine kinase) and adenovirus (hexon) genes. Adenovirus amplicons were sequenced and compared to original serotype. Thirty patients attended, 19 of whom had persistent papillary conjunctivitis. Evidence of adenovirus DNA was detected in 17 of 30 patients, 15 of whom also had evidence of a chronic papillary conjunctivitis. Adenovirus DNA was significantly associated with papillary conjunctivitis (P = 0.03). Adenovirus amplicons were successfully sequenced from six patients. Four patients harbored type 3 adenovirus, the same serotype with which they were infected originally 10 years previously. Two patients were infected originally with adenovirus serotype 3 but the current serotype was type 4. Infection of the ocular surface with adenovirus may predispose to the development of a persistent or recurrent conjunctivitis, the presence of which, appears to be associated with evidence of long term persistence of adenovirus DNA.     

An efficient SNP system for mouse genome scanning and elucidating strain relationships

A set of 1638 informative SNP markers easily assayed by the Amplifluor genotyping system were tested in 102 mouse strains, including the majority of the common and wild-derived inbred strains available from The Jackson Laboratory. Selected from publicly available databases, the markers are on average ~1.5 Mb apart and, whenever possible, represent the rare allele in at least two strains. Amplifluor assays were developed for each marker and performed on two independent DNA samples from each strain. The mean number of polymorphisms between strains was 608±136 SD. Several tests indicate that the markers provide an effective system for performing genome scans and quantitative trait loci analyses in all but the most closely related strains. Additionally, the markers revealed several subtle differences between closely related mouse strains, including the groups of several 129, BALB, C3H, C57, and DBA strains, and a group of wild-derived inbred strains representing several Mus musculus subspecies. Applying a neighbor-joining method to the data, we constructed a mouse strain family tree, which in most cases confirmed existing genealogies.     

Quantitative detection of respiratory Chlamydia pneumoniae infection by real-time PCR

Real-time PCR was evaluated as a quantitative diagnostic method for Chlamydia pneumoniae infection using different respiratory samples. Real-time PCR had efficiency equal to or better than that of nested touchdown PCR. This study confirmed sputum as the best sampling material to detect an ongoing C. pneumoniae infection.     

The effect of drinking tea at high altitude on hydration status and mood

The effect of drinking tea on hydration status and mood was studied in nine male and four female members of expeditions based at Mt. Everest base camp at an altitude of 5,345 m. Whilst exposed to altitude-cold diuresis, participants were subjected to a crossover experimental design comprising two 24-h dietary interventions. In the tea condition, hot brewed tea formed a major part of fluid intake, whereas in the no-tea condition tea was excluded from the diet. Subjects were prohibited in both cases from consuming other caffeinated beverages, caffeinated foods, and alcoholic drinks. Mean fluids ingested [mean (SE); tea=3,193 (259) ml versus no tea=3,108 (269) ml] and urine volume (tea=2,686 (276) ml versus no tea=2,625 (342) ml] were similar under both conditions. Statistical analysis found no difference in urine stimulated as a result of the tea intervention (P=0.81). Several markers of hydration status were also taken immediately pre and post each condition, including measures of urine specific gravity, urine electrolyte balance (K⁺, Na⁺), and urine colour. None of these measures indicated a difference in hydration status as a result of the dietary intervention in either the control or tea condition. A difference was, however, found in mood, with subjects reporting reduced fatigue when tea was included in the diet (P=0.005). The study shows therefore that even when drunk at high altitude where fluid balance is stressed, there is no evidence that tea acts as a diuretic when consumed through natural routes of ingestion by regular tea drinkers, but that it does have a positive effect on mood.