Validity of hair mineral testing

The variance of testing was compared between the College of American Pathologists clinical survey and that of a recent review about hair mineral testing. The review suggested that the accuracy of hair mineral testing was unreliable. In general, there was a greater range of variance in the College of American Pathologists testing results. These latter results are based on laboratory testing and are used as a “yardstick” to determine if a laboratory passes or fails that analyte and are considered a “gold standard.” An extract, which resulted from a method that avoided the washing step, was compared among five laboratories. Very good precision resulted, indicating that the varied washing steps used by the laboratories in a recent review were probably the source of much variance. Analysis of hair analysis seemed to yield important information in several historical or forensic cases involving Ludwig von Beethoven, Napoleon Bonaparte, ex-US-presidents Zachary Taylor and Andrew Jackson, and Charles Hall, an Arctic explorer. Several elements that were reviewed, including arsenic, cadmium, cobalt, germanium, lead, lithium, manganese, mercury, nickel, and thallium, showed relationships between body burden, dosage, and exposure or toxicity. Evidence of toxicity could not be found by measuring hair aluminum or vanadium. Chromium, selenium, and zinc seemed to have nutritional value. Ratios of hair elements with clinical importance could not be found.     

Spatial and temporal variation in fish assemblages of drying stream pools: The role of abiotic and biotic factors

Droughts and summer drying create unusual temporary aquatic habitats in the form of isolated pools in many small streams around the world. To examine spatial and temporal variation in fish community structure of drying stream pools, their relation to abiotic environmental variables, and associations among species, fish were sampled during summer 1995 and 1996 from pools of four streams in the Ozark mountains, Arkansas, USA. Redundancy analysis of physical-chemical variables showed significant differences among stream sites, but no significant difference between years or stream site by year interaction. Stream sites separated consistently along axes one (habitat heterogeneity) and two (temperature/canopy cover) in both years. Redundancy analysis of fish species-size class densities showed a significant stream site by year interaction. Groupings of stream sites based on fish assemblages were not well explained by physical-chemical variables measured at the pool scale, but were related to location within the drainage basin, and these groupings differed between years. There were 27 (15.8%) and 10 (5.8%) significant associations found among fish species-size classes in 1995 and 1996, respectively, and all but two significant associations in 1995 were positive. Pool depth, habitat heterogeneity, pool size and dissolved oxygen/canopy cover were important local abiotic factors depending on response variables examined. In both years, large fish total density, large central stoneroller density (80 mm TL), and small sunfish (<80 mm TL) density were positively related to pool depth. Otherwise, there was no consistent relationship between physical-chemical variables and dependent variables (fish density and species richness) within a year or between years for a given dependent variable. These results support the hypothesis that local abiotic factors are important in structuring fish assemblages in harsh environments, but the importance of those factors varies temporally, and regional influences appear to override local abiotic conditions as factors structuring fish assemblages in drying stream pools. Predation by terrestrial vertebrates may also be an important factor structuring these fish assemblages that has been largely overlooked.     

Interregional comparisons of sediment microbial respiration in streams

• 1 The rate of microbial respiration on fine‐grained stream sediments was measured at 371 first to fourth‐order streams in the Central Appalachian region (Maryland, Pennsylvania, Virginia, and West Virginia), Southern Rocky Mountains (Colorado), and California's Central Valley in 1994 and 1995.
• 2 Study streams were randomly selected from the United States Environmental Protection Agency's (USEPA) River Reach File (RF3) using the sample design developed by USEPA's Environmental Monitoring and Assessment Program (EMAP).
• 3 Respiration rate ranged from 0 to 0.621 g O₂ g^‐1 AFDM h^‐1 in Central Appalachian streams, 0‐0.254 g O₂ g^‐1 AFDM h^‐1 in Rocky Mountain streams, and 0‐0.436 g O₂ g^‐1 AFDM h^‐1 in Central Valley streams.
• 4 Respiration was significantly lower in Southern Rocky Mountain streams and in cold water streams (< 15 °C) of the Central Appalachians.
• 5 Within a defined index period, respiration was not significantly different between years, and was significantly correlated with stream temperature and chemistry (DOC, total N, total P, K, Cl, and alkalinity).
• 6 The uniformity of respiration estimates among the three study regions suggests that sediment microbial respiration may be collected at any number of scales above the site‐level for reliable prediction of respiration patterns at larger spatial scales.

     

A Regional Multiple-Stressor Rank-Based Ecological Risk Assessment for the Fjord of Port Valdez,Alaska

We conducted an ecological risk assessment of the marine environment of Port Valdez, a fjord in south-central Alaska. Because the assessment was regional rather than site-specific and contained a large number of different stressors in a variety of environments, we required a nontraditional method to estimate risks. We created a Relative Risk Model to rank and sum individual risks numerically within each subarea, from each source, and to each habitat. Application of this model involved division of Port Valdez into 11 subareas containing specific ecological and anthropogenic structures and activities. Within each subarea, the stressor sources were analyzed to estimate exposure of receptors within habitats leading to effects relevant to the chosen assessment endpoints. The subareas were analyzed and compared to form a Port-wide perspective of ecological risk. Available chemical concentrations from sediment and mussels collected from the Port were compared to various toxicological benchmarks as a partial confirmation of the risk analysis. An estimation of the risk of polycyclic aromatic hydrocarbons (PAHs) to marine invertebrates indicated low risk. The municipal boat harbor had the highest estimate, which reflected our relative risk rankings. The Relative Risk Model approach appears robust and has potential for use in situations where multiple stressors are of concern and for assessments covering broad geographic areas. In the Port Valdez assessment the approach provided relative risk rankings for chemical and physical stressors from various sources. But data were available for confirmation of risk estimates only for the chemical stressors. The rankings are relative, and extrapolation beyond the scenario in which they were developed is not warranted. Uncertainty is large, and the numerical scores collapse a multidimensional space into a single value. Use of just the numerical score out of context is more valid than with other indexes. The value of the approach lies in the relative rankings and the accounting of the components of the relative risk score.     

Lactate Production from Glucose and Response to Insulin in Perifused Adipocytes from Mesenteric and Epididymal Regions of Lean and Obese Rats

Lactate, an important metabolic substrate for peripheral tissues and the liver, is released in significant amounts from adipose tissue. Using a perifusion system, we measured lactate production from glucose and response to insulin in isolated mesenteric and epididymal adipocytes removed from fed or fasted male Wistar rats at two stages of growth and development: (a) lean rats (7 weeks to 9 weeks old, weighing ～250 g), and (b) fatter rats (6 months to 8 months old, weighing ～550 g). The results show that lactate production in perifused adipocytes is regulated by the prior nutritional state of the animals, by the adipose tissue region, and by the presence of insulin in the perifusate. In fat cells from lean rats, basal lactate production was significantly higher (p<0.05) in mesenteric cells when compared with epididymal cells, both in the fed state (7.8 nmol/10⁷ fat cells per minute vs. 2.9 nmol/10⁷ fat cells per minute) and after 2 days of fasting (13.6 nmol vs. 3.5 nmol). When the response to 1 mU/mL insulin was studied, however, the relative increase in lactate production produced by insulin was greater in the epididymal cells than in the mesenteric cells, in both the fed (194% vs. 91% over basal, respectively) and fasted (360% vs. 55% over basal, p<0.05) state. When larger epididymal adipocytes from fatter rats were compared with an equal number of smaller epididymal cells from leaner rats, the larger cells produced 4.99 nmol of lactate/10⁷ fat cells per minute, whereas the smaller cells produced 2.93 nmol (p=0.08). Large fat cells showed a small and nonsignificant response to insulin in either type of cell (epididymal vs. mesenteric) or nutritional state (fed vs. fasted). This study indicates that distinct regional differences exist in lactate production and response to insulin. Mesenteric adipose tissue, which drains directly into the portal vein and provides substrates to the liver, may be an important source of lactate for the hepatic processes of gluconeogenesis and glycogenesis.     

FROM MEDICAL RATIONING TO RATIONALIZING THE USE OF HUMAN RESOURCES FOR AIDS CARE AND TREATMENT IN AFRICA: A CASE FOR TASK SHIFTING

With a global commitment to scaling up AIDS care and treatment in resource‐poor settings for some of the most HIV‐affected countries in Africa, availability of antiretroviral treatment is no longer the principal obstacle to expanding access to treatment. A shortage of trained healthcare personnel to initiate treatment and manage patients represents a more challenging barrier to offering life‐saving treatment to all patients in need. Physician‐centered treatment policies accentuate this challenge. Despite evidence that task shifting for nurse‐centered AIDS patient care is effective and can alleviate severe physician shortages that currently obstruct treatment scale‐up, political commitment and policy action to support task shifting models of care has been slow to absent. In this paper we review the evidence in support of task shifting for AIDS treatment in Africa and argue that continued policy inaction amounts to unwarranted healthcare rationing and as such is ethically untenable.     

医疗投诉预警指数的建立及应用

应用环境质量指数的方法和原理,对国内5 385起医疗投诉进行分析。发现医疗投诉事件发生的主要原因为：医疗服务不到位（X₁）、医护人员态度不佳（X₂）、医院行政管理不善（X₃）、社会导向等因素不良而致的病人心理取向及药品质量等原因（X₄）。进一步推导出医疗投诉的预警指数：Ai=0.40X₁+0.32X₂+0.16X₃+0.12X₄ ,并提出了使用该指数的方法。应用此指数对某医院的医疗投诉进行评价,表明该院医疗投诉预警指数为1.25,属警报水平（Ⅲ级）,同时也指出了该院医疗投诉的重点检查对象和治理的重点。应用此指数不仅可以对医疗投诉事件进行前瞻性的预测,确定重点的管理对象,而且可以找出主要的隐患和管理重点,为宏观管理确定依据。     

中国情境下医院社会责任的概念及内涵解析

《病历书写基本规范》在原试行版经过为期7年多的实践的基础上得到了进一步的完善,并于2010年3月1日起正式施行。与试行版相比,新的《病历书写基本规范》彰显出七大特点,但在对文书记录者身份的要求、实习医务人员及试用期医务人员书写病历内容范围、前后用词的统一性等方面仍值得商榷。对此提出建议：明确每一种文书记录者的身份或资格;用词规范并前后统一;高度重视医嘱管理。