Body mass index,weight change,and death in older adults: the systolic hypertension in the elderly program

The relation between relative weight and health differs between young and old. In older populations, weight change may cloud the association between a single relative weight and health outcomes. To determine whether weight or weight change is a more important determinant of mortality in a population of older adults, the authors analyzed data from the Systolic Hypertension in the Elderly Program (1984-1990), a randomized clinical trial testing the efficacy of antihypertensive drug treatment to reduce the risk of stroke in older adults (aged 60 years or more) with isolated systolic hypertension. After adjustment for covariates, an average annualized weight loss of at least 1.6 kg/year (odds ratio = 4.9), a weight loss between 1.6 and 0.7 kg/year (odds ratio = 1.7), a weight gain of more than 0.5 kg/year (odds ratio = 2.4), and a baseline body mass index of less than 23.6 (odds ratio = 1.4) all had a significant (p < 0.05) association with all-cause mortality compared with a referent group that was weight stable and of intermediate body mass index (23.6 to <28.0 kg/m(2)) and weight change (-0.7 to <0.5 kg/year). The authors conclude that, in older adults, dynamic measures (e.g., annualized weight change) of weight change predict mortality better than do static weight measures (e.g., baseline body mass index). Even in those with high or low baseline body mass index, weight stability is associated with a lower mortality risk.     

Detection of rare mutant alleles by restriction endonuclease-mediated selective-PCR: assay design and optimization

BACKGROUND: Restriction endonuclease-mediated selective (REMS)-PCR, allows detection of point mutations, deletions, and insertions. Reactions require concurrent activity of a restriction endonuclease (RE) and a DNA polymerase, both of which must be sufficiently thermostable to retain activity during thermocycling. The inclusion of the RE in REMS-PCR inhibits amplification of sequences containing the RE recognition site, thus producing selective amplification of sequences that lack the RE site. METHODS: Assays were used that allowed the selection of conditions that produce concurrent RE/DNA polymerase activity. The RE thermostability assay involved thermocycling a RE under various conditions and assessing residual cleavage activity at various time points. Conditions found to preserve RE activity during thermocyling were then tested for their compatibility with DNA polymerase-mediated PCR. RESULTS: A range of conditions that preserve activity of the RE BstNI over 30 cycles of PCR was identified. A subset of these conditions was subsequently found to mediate specific amplification using Taq DNA polymerase. These conditions were used to develop a REMS-PCR protocol for the detection of mutations at codon 12 of the K-ras gene. This protocol allowed the detection of 1 mutant allele in a background of 1000 wild-type alleles. The presence of primer sets for RE and PCR control amplicons provided unambiguous assessment of mutant status. CONCLUSION: Implementation of the assays described may facilitate development of REMS-PCR assays targeted to other loci associated with disease.     

Development and validation of the injury severity assessment survey/parent report: a new injury severity assessment survey

OBJECTIVE: To develop and pilot test a telephone-based survey instrument that enables parents to identify and characterize the body region and severity of childhood injuries using the Abbreviated Injury Scale (AIS) scoring system. DESIGN: A prospective cross-sectional survey. SETTING: The emergency department of an urban, tertiary care, pediatric trauma center. PARTICIPANTS: One hundred forty-seven parents of children younger than 18 years and seen in the emergency department for acute treatment of an unintentional injury. INTERVENTIONS: None. MAIN OUTCOME MEASURE: The degree of agreement, measured as sensitivity, specificity, and kappa statistic, between medical record information and parents' responses to the telephone survey regarding the identification and characterization of clinically significant (AIS > or =2) injuries. RESULTS: The survey, known as the Injury Severity Assessment Survey/Parent Report, was developed via a systematic review of the AIS 1990 manual. Answers to questions were developed in a way that enabled automated coding of responses into AIS scores or ranges of scores. The sensitivity of the survey (its ability to detect injuries scoring 2 or more on the AIS that were documented in the medical record) varied somewhat by the body region of injury, ranging from 88% for head, face, neck, and spine injuries to 95% for extremity injuries. Intermediate sensitivity (92%) was noted for the detection of significant chest and abdomen injuries. The specificity of the survey (its ability to rule out the presence of a significant injury when one was not documented in the medical record) was more than 95% in each of the 3 body region groups. The kappa statistics for the 3 body region groups ranged from 0.89 to 0.92. CONCLUSIONS: A new telephone-based survey has been developed that enables parents to characterize their child's injuries by body region and to differentiate between minor injuries and more significant injuries using a well-established injury classification system. This survey has a significant advantage over previous telephone-based or written surveys of childhood injuries and may be particularly valuable in population-based (e.g., random-digit dial surveys) or multi-institutional studies of pediatric injuries.     

Multiple unit activity recorded from amygdala central nucleus during Pavlovian heart rate conditioning in rabbit

Using a Pavlovian heart rate conditioning paradigm, a rapid development of short latency increases in the multiple unit activity of the amygdala central nucleus were observed in response to a tone conditioned stimulus. In some cases the increases in multiple unit response showed a parallel development with the conditioned develerative heart rate response and were significantly correlated with it. These results suggest a direct role for the central nucleus in the expression of conditioned heart rate responding in rabbit.     

Moderate chronic pain, weight and dietary intake in African-American adult patients with sickle cell disease

In this exploratory study, we evaluated weight status and dietary intake patterns during painful episodes in adult patients with SCD. Specifically, we explored the relation between pain severity and body mass index (BMI), and we tested the hypothesis that dietary intake would be reduced and dietary content altered during periods of increased pain. We conducted an analysis of survey data from 62 patients involved in a longitudinal evaluation of the relationship of medical and psychosocial factors to pain. Nearly half of patients with SCD were overweight, and 20% were obese. BMI was positively related to interference associated with pain. Although BMI was not statistically associated with reported pain severity, >40% of patients reported that they perceived their pain to be affected by their weight. Less than 20% of patients reported that they perceived that their weight affected their pain. Regarding dietary patterns, the majority of patients reported eating less during episodes of pain and significantly decreasing their intake of fats and proteins. We conclude that there is a need to better understand the relation among weight, dietary patterns and pain in patients with SCD in order to provide patients with accurate education and effective treatment recommendations for managing their disease and reducing current and future risks of lifestyle and disease-related morbidities.     

Quantifying scatter in Shack-Hartmann images to evaluate nuclear cataract

PURPOSE: Quantify and localize lenticular forward scatter using Shack-Hartmann wavefront sensing (SHWS) as single-valued metrics and a scatter map, and to examine the relationships between forward scatter and backscatter metrics and visual acuity. METHODS: We obtained SHWS images from 148 patients in the Texas Investigation of Cataract Optics study. Patient age was 22 to 84 years, with Lens Opacities Classification System III (LOCS III) nuclear opalescence (NO) scores ranging from 0.8 to 5.6. Visual acuities were measured at photopic (280 cd/m2) high (VA(PHC)) and low contrast (VA(PLC)) and mesopic (0.75 cd/m2) high (VA(MHC)) and low contrast (VA(MLC)). Scattering was described in a scatter map and by five single-valued metrics characterizing SHWS lenslet point spread functions. The relationships between scatter and visual acuity were tested using linear regression. RESULTS: Visual acuities decreased proportional to both LOCS III NO (R2=up to 39%) and scatter metrics (R2=up to 21%). Stepwise multiple linear regression improved visual acuity prediction by including a backscatter and a forward scatter metric (R2 up to 51.2%). For the subjects over age 60 years (N=46, 68.8+/-6.12 years), the forward scatter metrics explain as much variance in visual acuities (R2=up to 29%) as LOCS III NO (R2=up to 26%). Combined they accounted for up to 48.8% of visual acuity variance. CONCLUSION: Forward light scatter can be quantified using SHWS and the resulting metrics explain significant variance in visual acuity, especially in the aging eye. Together with a backscatter metric they explain approximately 50% of the variance in VA.     

Technology assessment for radiologists

Health technology assessment is the systematic and quantitative evaluation of the safety, efficacy, and cost of health care interventions. This article outlines aspects of technology assessment of diagnostic imaging. First, it presents a conceptual framework of a hierarchy of levels of efficacy that should guide thinking about imaging test evaluation. In particular, the framework shows how the question answered by most evaluations of imaging tests, "How well does this test distinguish disease from the nondiseased state?" relates to the fundamental questions for all health technology assessment, "How much does this intervention improve the health of people?" and "What is the cost of that improvement?" Second, it describes decision analysis and cost-effectiveness analysis, which are quantitative modeling techniques usually used to answer the two core questions for imaging. Third, it outlines design and operational considerations that are vital if researchers who are conducting an experimental study are to make a quality contribution to technology assessment, either directly through their findings or as an input into decision analyses. Finally, it includes a separate discussion of screening--that is, the application of diagnostic tests to nonsymptomatic populations--because the requirements for good screening tests are different from those for diagnostic tests of symptomatic patients and because the appropriate evaluation methods also differ.