Modelling of protein turnover provides insight for metabolic demands on those specific amino acids utilised at disproportionately faster rates than other amino acids.

The nitrogen balance is regulated by factors such as diet, physical activity, age, pathogenic challenges, and climatic conditions. A paradigm was developed from published recommended rates of protein intake (g/kg/day) with corresponding rates of endogenous protein turnover and excretion, to extrapolate amino acid balances under various conditions. The average proportions of amino acids in the ingested proteins representing a well-balanced diet were used to assess intake and an average human composition profile from five major high-turnover proteins in the body to assess endogenous protein turnover. The amino acid excretion profiles for urine and sweat were constructed for males and females from published data. The model calculated the nitrogen balances for a range of amino acids to determine the amino acid requirements to support daily exertion. Histidine, serine, glycine, and ornithine were in negative balances in males and females and this potential deficit was greater in the higher body-mass ranges. Conversely, leucine, isoleucine, and valine were conserved during nitrogen flux and resulted in positive balances. The model was run under a scenario of high demand for the synthesis of IgG during a response to an infectious challenge which indicated that these were increased requirements for tyrosine, threonine, and valine. It was concluded that these amino acids represent points of limitation to anabolic metabolism by restriction of their supply at critical times of demand. This would especially occur under conditions of fitness training, maintaining intensive exercise regimes, facilitating responses to pathogenic challenge, or recovery from injury.

Sex differences in amino acids lost via sweating could lead to differential susceptibilities to disturbances in nitrogen balance and collagen turnover.

Fluid collected during sweating is enriched with amino acids derived from the skin's natural moisturising factors and has been termed "faux" sweat. Little is known about sex differences in sweat amino acid composition or whether faux sweat amino acid losses affect nitrogen balance. Faux sweat collected by healthy adults (n = 47) after exercise, and at rest by chronic fatigue patients, was analysed for amino acid composition. Healthy females had higher total amino acid concentrations in sweat (10.5 ± 1.2 mM) compared with healthy males (6.9 ± 0.9 mM). Females had higher levels of 13 amino acids in sweat including serine, alanine and glycine. Higher hydroxyproline and proline levels suggested greater collagen turnover in females. Modelling indicated that with conservative levels of exercise, amino acid losses in females via faux sweat were triple than those predicted for urine, whereas in males they were double. It was concluded that females were more susceptible to key amino acid loss during exercise and/or hot conditions. Females reporting chronic fatigue had higher levels of methionine in faux sweat than healthy females. Males reporting chronic fatigue had higher levels of numerous amino acids in faux sweat compared to healthy males. Higher amino acid loss in faux sweat associated with chronic fatigue could contribute to a hypometabolic state. Depending on activity levels, climatic conditions and gender, amino acid losses in sweat and skin leachate could influence daily protein turnover where periods of continuously high turnover could lead to a negative net nitrogen balance.

Meta-analysis of antibiotics for simple hand injuries requiring surgery.

BACKGROUND: Simple hand trauma is very common, accounting for 1·8 million emergency department visits annually in the USA alone. Antibiotics are used widely as postinjury prophylaxis, but their efficacy is unclear. This meta-analysis assessed the effect of antibiotic prophylaxis versus placebo or no treatment on wound infection rates in hand injuries managed surgically. METHODS: Embase, MEDLINE, PubMed, Cochrane Central, ClinicalTrials.gov and the World Health Organization International Clinical Trials Portal were searched for published and unpublished studies in any language from inception to September 2015. The primary outcome was the effect of antibiotic prophylaxis on wound infection rates. Open fractures, crush injuries and bite wounds were excluded. Study quality was assessed using the Cochrane risk-of-bias tool. Data were pooled using random-effects meta-analysis, and risk ratios (RRs) and 95 per cent c.i. obtained. RESULTS: Thirteen studies (2578 patients) were included, comprising five double-blind randomized clinical trials, five prospective trials and three cohort studies. There was no significant difference in infection rate between the antibiotic and placebo/no antibiotic groups (RR 0·89, 95 per cent c.i. 0·65 to 1·23; P = 0·49). Subgroup analysis of the five double-blind randomized clinical trials (864 patients) again found no difference in infection rates (RR 0·66, 0·36 to 1·21; P = 0·18). CONCLUSION: There was moderate-quality evidence that routine use of antibiotics does not reduce the infection rate in simple hand wounds that require surgery.

ICU fire evacuation preparedness in London: a cross-sectional study.

BACKGROUND: Hospital fires present a sporadic but significant threat to patients and staff. This is especially so within an intensive care unit (ICU) setting, due to the complexity of moving acutely unwell patients reliant on invasive monitoring and organ support. Despite an average of 500 in-hospital fires reported to the UK department of health per annum, causing 65 injuries and 1-2 fatalities, the readiness of ICUs for urgent evacuation has not been assessed. METHODS: A cross-sectional survey of all 50 adult and paediatric ICUs within the London Postgraduate Deanery was conducted; neonatal units were excluded. The senior nurse at each unit was asked to complete a 90-question structured questionnaire, covering unit patient characteristics, design, equipment, training, and their evacuation plan. Thirty-five of 50 (70%) responded within 2 months of the study. RESULTS: Significant weaknesses were reported in unit design, equipment, and planning. Unit design was compromised by inadequate fire doors (20%), ventilation cut-outs (17%), and escape routes (up to 60%). The ability to evacuate multiple patients simultaneously may be limited by a lack of portable monitoring equipment (49% of beds) and emergency drug supplies (20% of beds). Evacuation plans were often limited in their scope (96% expected to remain on their floor; 14% had plans to obtain medications after evacuation), and not rehearsed (60%). Staff training, while well provided for permanent staff, is less so for temporary staff (34%). CONCLUSIONS: Forward planning for an urgent evacuation can be improved.

How well does ICD9 represent phrases used in the medical record problem list?

We are considering using the International Classification of Diseases with Clinical Modifications, Ninth Revision (ICD9) as the basis for an automated problem list for a clinical information system. To determine physician satisfaction with an ICD9 representation of phrases used in the medical record problem list, we asked 6 physicians to evaluate ICD9 representations of 332 phrases taken from medical record problem lists, using a scale of 1(extremely dissatisfied) to 5 (extremely satisfied). The mean score was 3.0; intraclass correlation for 25 phrases given to all 6 evaluators was 0.47. In 45% of the phrases the physicians were dissatisfied with the ICD9 representation. In developing an automated problem list it is desirable to improve the level of satisfaction of clinician users above this level. This could be done by modifying ICD9, using a different vocabulary to represent the problem list, or improving the method of assigning ICD9 codes.

Development and evaluation of serotype- and group-specific fluorogenic reverse transcriptase PCR (TaqMan) assays for dengue virus.

Five fluorogenic probe hydrolysis (TaqMan) reverse transcriptase PCR (RT-PCR) assays were developed for serotypes 1 to 4 and group-specific detection of dengue virus. Serotype- and group-specific oligonucleotide primers and fluorogenic probes were designed against conserved regions of the dengue virus genome. The RT-PCR assay is a rapid single-tube method consisting of a 30-min RT step linked to a 45-cycle PCR at 95 and 60 degrees C that generates a fluorogenic signal in positive samples. Assays were initially evaluated against cell culture-derived dengue stock viruses and then with 67 dengue viremic human sera received from Peru, Indonesia, and Taiwan. The TaqMan assays were compared to virus isolation using C6/36 cells followed by an immunofluorescence assay using serotype-specific monoclonal antibodies. Viral titers in sera were determined by plaque assay in Vero cells. The serotype-specific TaqMan RT-PCR assay detected 62 of 67 confirmed dengue virus-positive samples, for a sensitivity of 92.5%, while the group-specific assay detected 66 of 67 confirmed dengue virus-positive samples, for a sensitivity of 98.5%. The TaqMan RT-PCR assays have a specificity of 100% based on the serotype concordance of all assays compared to cell culture isolation and negative results obtained when 21 normal human sera and plasma samples were tested. Our results demonstrate that the dengue virus TaqMan RT-PCR assays may be utilized as rapid, sensitive, and specific screening and serotyping tools for epidemiological studies of dengue virus infections.