bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sites of Binding and Orientation in a Four‐Location Model for Protein Stereospecificity
Authors: Mesecar Andrew D. , Koshland Daniel E. 
Published: July 2002

AbstractThe stereospecificity of the enzyme isocitrate dehydrogenase was examined by steady‐state kinetics and x‐ray crystallography. The enzyme has the intriguing property that the apoenzyme in the absence of divalent metal showed a selectivity for the inactive l‐enantiomer of the substrate isocitrate, whereas the enzyme containing magnesium showed selectivity for the physiologically active d‐enantiomer. The hydrogen atom on the C2 carbon that is transferred during the reaction was, in both the d‐ and l‐isocitrate complexes, in an orientation very close to that expected for delivery of a hydride ion to the cosubstrate NADPT+. The beta‐carboxylate that is eliminated as a CO2 molecule during the reaction occupied the same site on the protein in both the d‐ and l‐isocitrate complexes. In addition, the C3 carbon was in the same protein site in both the d‐ and l‐enantiomers. Only the fourth group, the OH atom, was in a very different position in the apo enzyme and in the metal‐containing complexes. A four‐location model is necessary to explain the enantiomeric specificity of IDH in contrast to the conventional three‐point attachment model. The thermodynamic and kinetic ramifications of this model are explored.
Comparison of Maternal and Infant Outcomes between Vacuum Extraction and Forceps Deliveries
Authors: Wen Shi Wu , Liu Shiliang , Kramer Michael S. , Marcoux Sylvie , Ohlsson Arne , Sauvé Reg , Liston Robert 
Published: July 2002

Abstract
The authors conducted a population-based historical cohort study in the Canadian province of Quebec to assess the maternal and infant outcomes associated with vacuum extraction and forceps deliveries. The study database contains information on 305,391 mother-infant dyads (linked by a common institutional code and hospital chart number) for singleton live vaginal births with a nonbreech presentation at the gestational age of 37 or more completed weeks and a birth weight between 2,500 and 4,000 g during fiscal years 1991/1992 to 1995/1996. Of the births, 31,015 were delivered by vacuum extraction, and 18,727 were delivered by forceps. Compared with delivery by forceps, the adjusted risk ratios for third-/fourth-degree perineal laceration, intracranial hemorrhage, subdural or cerebral hemorrhage, intraventricular hemorrhage, subarachnoid hemorrhage, cephalhematoma, and neonatal in-hospital death were 0.48 (95% confidence interval: 0.45, 0.50), 1.28 (95% confidence interval: 0.73, 2.25), 0.97 (95% confidence interval: 0.49, 1.93), 0.99 (95% confidence interval: 0.16, 5.97), 5.44 (confidence interval: 1.26, 23.43), 2.02 (95% confidence interval: 1.89, 2.16), and 0.93 (95% confidence interval: 0.32, 2.70), respectively. The authors conclude that vacuum extraction causes less maternal trauma but may increase the risk of cephalhematoma and certain types of intracranial hemorrhage (e.g., subarachnoid hemorrhage).
Living Arrangements, Social Integration, and Change in Functional Health Status
Authors: Michael Yvonne L. , Berkman Lisa F. , Colditz Graham A. , Kawachi Ichiro 
Published: July 2002

Abstract
Limited prospective data have examined the association between living arrangements and emotional well-being. The authors assessed whether older women living with a spouse were less likely to experience a decline in mental health, vitality, or physical function compared with women living alone or with nonspouse others. The association between living arrangement and 4-year change in functional health status was examined prospectively among 28,324 women aged 60–72 years in the Nurses' Health Study. After adjustment for age, baseline function, comorbid conditions, and health behaviors, women living alone had lower risk of decline in mental health (relative risk (RR) = 0.73, 95 percent confidence interval (CI): 0.65, 0.81) and vitality (RR = 0.72, 95 percent CI: 0.65, 0.80) compared with those living with a spouse. Contact with friends and relatives and level of social engagement were significantly protective against a decline in mental health among women living alone but not among women living with a spouse. These results suggest that women living independently are neither socially isolated nor at increased risk for decline in functional health status. In fact, these women actually fare better on measures of psychologic function than do women living with a spouse.
Mortality Reduction with Air Bag and Seat Belt Use in Head-on Passenger Car Collisions
Authors: Crandall Cameron S. , Olson Lenora M. , Sklar David P. 
Published: July 2002

Abstract
To assess the efficacy of occupant protection systems, the authors measured the mortality reduction associated with air bag deployment and seat belt use for drivers involved in head-on passenger car collisions in the United States. They used a matched case-control design of all head-on collisions involving two passenger cars reported to the Fatality Analysis Reporting System in 1992–1997, and driver mortality differences between the paired crash vehicles for air bag deployment and seat belt use were measured with matched-pair odds ratios. Conditional logistic regression was used to adjust for multiple effects. There were 9,859 head-on collisions involving 19,718 passenger cars and drivers. Air bag deployment reduced mortality 63% (crude odds ratio (OR) = 0.37, 95% confidence interval (CI): 0.32, 0.42), while lap-shoulder belt use reduced mortality 72% (OR = 0.28, 95% CI: 0.25, 0.31). In a conditional logistic model that adjusted for vehicle (rollover, weight, age) and driver (age, sex) factors, air bags (OR = 0.71, 95% CI: 0.58, 0.87) and any combination of seat belts (OR = 0.25, 95% CI: 0.22, 0.29) were both associated with reduced mortality. Combined air bag and seat belt use reduced mortality by more than 80% (OR = 0.18, 95% CI: 0.13, 0.25). Thus, this study confirms the independent effect of air bags and seat belts in reducing mortality.
Testosterone Concentrations in Women Aged 25–50 Years: Associations with Lifestyle, Body Composition, and Ovarian Status
Authors: Sowers MF. , Beebe J. L. , McConnell D. , Randolph John , Jannausch M. 
Published: July 2002

Abstract
While there is substantial evidence of the importance of endogenous and exogenous estrogen in reproductive health and chronic disease, there is little consideration of androgens in women's health. In the Michigan Bone Health Study (1992–1995), the authors examined the correlates of testosterone concentrations in pre- and perimenopausal women (i.e., age, menopausal status, body composition, and lifestyle behaviors) in a population-based longitudinal study including three annual examinations among 611 women aged 25–50 years identified through a census in a midwestern community. Current smokers had the highest testosterone concentrations with decreasing values in former and nonsmokers (p = 0.0001). Body composition measures (body mass index, body fat (%), weight (kg), lean body mass (kg), and fat mass (kg)) were significantly and positively associated with total testosterone concentrations in a dose-response manner. Hysterectomy with oophorectomy was associated with significantly lower testosterone concentrations. Alcohol consumption, physical activity, and dietary macronutrient intake were not associated with testosterone concentrations. This is one of the first studies to examine correlates of serum testosterone concentrations in anticipation of the growing interest in the role of androgens in women's health. The greater circulating levels of testosterone in obese women and smokers suggest that testosterone concentrations should be considered in the natural history of disease conditions where obesity and smoking are risk factors, including cardiovascular disease.
High Plasma Nonesterified Fatty Acids Are Predictive of Cancer Mortality but Not of Coronary Heart Disease Mortality: Results from the Paris Prospective Study
Authors: Aline Charles Marie , Fontbonne Annick , Thibult Nadine , Claude Jean-Roger , Warnet Jean-Michel , Rosselin Gabriel , Ducimetière Pierre , Eschwège Eveline 
Published: July 2002

Abstract
To assess the association of fasting plasma nonesterified fatty acid (NEFA) concentration with the risk of death from coronary heart disease and cancer, the authors computed 15-year mortality rates for the 4,589 working men aged 43–53 years who were included in the Paris Prospective Study between 1967 and 1972. A total of 251 and 126 men died from cancer and coronary heart disease, respectively. For coronary heart disease death, the age- and tobacco-adjusted relative risk for men in the highest 20% of the fasting plasma NEFA concentrations compared with those in the lowest 80% was 1.54 (95% confidence interval (CI): 1.01, 2.34). It became nonsignificant after further adjustment for blood pressure, iliac/thigh ratio, and plasma insulin and cholesterol concentrations. In contrast, a high fasting plasma NEFA concentration exhibited a strong independent relation with cancer mortality (relative risk = 1.66, 95% CI: 1.25, 2.21, after adjustment for age, cigarette consumption, heart rate, and body mass index). Despite pathophysiologic mechanisms linking NEFA metabolism with visceral fat and plasma glucose, insulin, and triglyceride concentrations, the plasma NEFA concentration does not appear to be a good marker for coronary heart disease risk. In contrast, an unexpected association with cancer mortality was found that may point to the need for further investigation.
Modeling Changes in CD4-positive T-Lymphocyte Counts after the Start of Highly Active Antiretroviral Therapy and the Relation with Risk of Opportunistic Infections The Aquitaine Cohort, 1996–1997
Authors: Binquet C. , Chêne G. , Jacqmin-Gadda H. , Journot V. , Savès M. , Lacoste D. , Dabis F. 
Published: July 2002

Abstract
After initiation of a treatment for human immunodeficiency virus type 1 infection containing a protease inhibitor, immune restoration associated with increases in CD4-positive (CD4+) T lymphocyte count may be delayed. In a sample of patients who had been prescribed protease inhibitors for the first time, the authors tested to see whether there was a minimal duration of CD4+ cell count increase before the increase had an impact on the occurrence of opportunistic infections. The evolution (difference between time t and baseline) of CD4+ cell count was modeled using a mixed effects linear model. Changes in CD4+ count estimated by this model were then included as time-dependent covariates in a proportional hazards model. Finally, the authors tested for the existence of a CD4+ change × time interaction. The authors used a sample of 553 French patients first prescribed protease inhibitors in 1996 and followed for a median of 16 months. During the first 120 days, there was no association between CD4+ change and the rate of opportunistic infections. After 120 days, each 50-cell/mm3 increase in CD4+ count was associated with a 60% (95% confidence interval: 45, 72) reduction in the incidence of opportunistic infections. These results, based on modeling of CD4+ cell response, at least indirectly reinforce the concept of a delayed but possible immune recovery with the use of protease inhibitors. The findings support the potential for interruption of certain types of prophylaxis against opportunistic infections under reasonable conditions of duration of antiretroviral therapy and sustained CD4+ cell response.
Is Shorter Always Better? Relative Importance of Questionnaire Length and Cognitive Ease on Response Rates and Data Quality for Two Dietary Questionnaires
Authors: Subar Amy F. , Ziegler Regina G. , Thompson Frances E. , Johnson Christine Cole , Weissfeld Joel L. , Reding Douglas , Kavounis Katherine H. , Hayes Richard B. 
Published: July 2002

Abstract
In this study, the authors sought to determine the effects of length and clarity on response rates and data quality for two food frequency questionnaires (FFQs): the newly developed 36-page Diet History Questionnaire (DHQ), designed to be cognitively easier for respondents, and a 16-page FFQ developed earlier for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The PLCO Trial is a 23-year randomized controlled clinical trial begun in 1992. The sample for this substudy, which was conducted from January to April of 1998, consisted of 900 control and 450 screened PLCO participants aged 55–74 years. Controls received either the DHQ or the PLCO FFQ by mail. Screenees, who had previously completed the PLCO FFQ at baseline, were administered the DHQ. Among controls, the response rate for both FFQs was 82%. Average amounts of time needed by controls to complete the DHQ and the PLCO FFQ were 68 minutes and 39 minutes, respectively. Percentages of missing or uninterpretable responses were similar between instruments for questions on frequency of intake but were approximately 3 and 9 percentage points lower (p ≤ 0.001) in the DHQ for questions on portion size and use of vitamin/mineral supplements, respectively. Among screenees, response rates for the DHQ and the PLCO FFQ were 84% and 89%, respectively, and analyses of questions on portion size and supplement use showed few differences. These data indicated that the shorter FFQ was not better from the perspective of response rate and data quality, and that clarity and ease of administration may compensate for questionnaire length.
Associations of Blood Lead, Dimercaptosuccinic Acid-chelatable Lead, and Tibia Lead with Neurobehavioral Test Scores in South Korean Lead Workers
Authors: Schwartz Brian S. , Lee Byung-Kook , Lee Gap-Soo , Stewart Walter F. , Lee Sung-Soo , Hwang Kyu-Yoon , Ahn Kyu-Dong , Kim Yong-Bae , Bolla Karen I. , Simon David , Parsons Patrick J. , Todd Andrew C. 
Published: July 2002

Abstract
The authors performed a cross-sectional study to evaluate associations between blood lead, tibia lead, and dimercaptosuccinic acid (DMSA)-chelatable lead and measures of neurobehavioral and peripheral nervous system function among 803 lead-exposed workers and 135 unexposed controls in South Korea. The workers and controls were enrolled in the study between October 1997 and August 1999. Central nervous system function was assessed with a modified version of the World Health Organization Neurobehavioral Core Test Battery. Peripheral nervous system function was assessed by measuring pinch and grip strength and peripheral vibration thresholds. After adjustment for covariates, the signs of the β coefficients for blood lead were negative for 16 of the 19 tests and blood lead was a significant predictor of worse performance on eight tests. On average, for the eight tests that were significantly associated with blood lead levels, an increase in blood lead of 5 µg/dl was equivalent to an increase of 1.05 years in age. In contrast, after adjustment for covariates, tibia lead level was not associated with neurobehavioral test scores. Associations with DMSA-chelatable lead were similar to those for blood lead. In these currently exposed workers, blood lead was a better predictor of neurobehavioral performance than was tibia or DMSA-chelatable lead, mainly in the domains of executive abilities, manual dexterity, and peripheral motor strength.
Metabolic Syndrome and Ischemic Heart Disease in Elderly Men and Women
Authors: Lindblad Ulf , Langer Robert D. , Wingard Deborah L. , Thomas Ronald G. , Barrett-Connor Elizabeth L. 
Published: July 2002

Abstract
Associations between metabolic syndrome components and prevalent ischemic heart disease (IHD) were investigated in a cross-sectional, community-based study of elderly men (n = 1,015) and women (n = 1,259) in Rancho Bernardo, California, in 1984–1987. In both sexes, there were significant positive associations between IHD defined by resting electrocardiogram criteria and age, systolic blood pressure, fasting and postchallenge hyperglycemia, total cholesterol/high density lipoprotein cholesterol (HDL cholesterol) ratio, and triglycerides and an inverse significant association with HDL cholesterol. High collinearity and interactions between serum insulin and metabolic syndrome variables were accounted for by uncorrelated principal components identified by factor analysis. In both men and women, three uncorrelated principal components were identified, representing a central metabolic factor (body mass index, fasting and 2-hour serum insulin, high serum triglycerides, and low HDL cholesterol), a glucose factor, and a blood pressure factor. In a multivariate model with age and sex, all three factors were significantly associated with IHD by electrocardiogram criteria; central metabolic factor (odds ratio (OR) = 1.6, p = 0.001), glucose factor (OR = 1.4, p &lt; 0.001), blood pressure factor (OR = 1.2, p = 0.005), age (10 years) (OR = 1.8, p &lt; 0.001), and female sex (OR = 0.5, p &lt; 0.02). Similar results were obtained in analyses using clinically manifest IHD as the outcome. These results support the thesis that the metabolic syndrome exerts effects through different risk factors by different mechanisms.
Latex Sensitization in Health Care Workers and in the US General Population
Authors: Garabrant David H. , Roth H. Daniel , Parsad Romain , Ying Gui-Shuang , Weiss Jay 
Published: July 2002

Abstract
Sensitization to natural rubber latex is a prerequisite to type I immediate hypersensitivity reactions (urticaria, angioedema, anaphylaxis, and allergic rhinitis) that result from subsequent latex exposure. This study examines occupations in which latex glove use is common to determine whether it is associated with increased prevalence odds of latex sensitization (measured by latex-specific immunoglobulin E antibodies) by using data from 5,512 adults aged 17–60 years from the Third National Health and Nutrition Examination Survey (1988–1991). After other factors associated with latex sensitization were controlled for, there was a nonsignificant association between longest-held jobs in health care and latex sensitization (odds ratio (OR) = 1.49, 95 percent confidence interval (CI): 0.92, 2.40). For current occupations, latex sensitization was not associated with health care work in which gloves were used (OR = 1.17, 95 percent CI: 0.51, 2.65) or with other occupations in which latex glove use is common (OR = 1.01, 95 percent CI: 0.49, 2.07) compared with other occupations. Current health care workers who reported not using gloves were at increased risk of latex sensitization, both among those without a history of childhood atopy (OR = 2.30, 95 percent CI: 1.04, 5.13) and those with such a history (OR = 28.04, 95 percent CI: 3.64, 215.97). This odds ratio heterogeneity suggests that subjects with childhood atopy may be at high risk of latex sensitization.
Relation of Alleles of the Sodium-Potassium Adenosine Triphosphatase α2 Gene with Blood Pressure and Lead Exposure
Authors: Glenn Barbara S. , Stewart Walter F. , Schwartz Brian S. , Bressler Joseph 
Published: July 2002

Abstract
Lead is associated with elevated blood pressure, although the mechanism of action is unknown. Genetic differences in sodium-potassium adenosine triphosphatase (Na+-K+ATPase) could explain some of the variation in the strength of the blood pressure-blood lead relation that has been observed in previous studies. In 1996–1997, the authors studied the association of blood pressure, hypertension prevalence, and polymorphisms in the gene for the α2 subunit of Na+-K+ATPase (ATP1A2) among 220 former organolead manufacturing workers from New Jersey. Subjects were genotyped for a restriction fragment length polymorphism (RFLP) on the ATP1A2 gene. The association between blood lead and blood pressure was stronger among persons who were homozygous for the variant allele. Genotype was also associated with hypertension (adjusted odds ratio = 7.7; 95% confidence interval: 1.9, 31.4). Finally, the variant allele was 1.8 times more common among African Americans than among Caucasians. The RFLP may indicate susceptibility to the effect of lead on blood pressure. Moreover, the α2 gene (or a closely linked gene) may contribute to the pathophysiology of hypertension. However, because the number of subjects (especially African Americans) with the susceptible genotype in this study was small, these observations should be considered preliminary.
Life-Course Predictors of Ultrasonic Heel Measurement in a Cross-sectional Study of Immigrant Women from Southeast Asia
Authors: Lauderdale Diane S. , Salant Talya , Han Katherine L. , Tran Phuong L. 
Published: July 2002

Abstract
Few studies address chronic disease risk for Southeast Asians in the United States. In 1999, the authors conducted a cross-sectional study of bone mineral density (BMD) estimated from ultrasonic calcaneal measurements in women born in Southeast Asia who then lived in Chicago, Illinois. The study addressed three questions: Do Southeast-Asian women have relatively low BMD? What factors before and after immigration are associated with BMD? Are factors that reflect the childhood/adolescent environment equally associated with BMD for postmenopausal and premenopausal women? An interviewer-administered bilingual questionnaire collected immigration, reproductive, and lifestyle data from 213 women (aged 20–80 years) born in Vietnam, Cambodia, or Laos. The authors found that the estimated mean BMD of postmenopausal Southeast-Asian women was lower than the reference values for White women. Four summary indicators of childhood/adolescent environment were predictive of higher BMD: more years of education, earlier age at menarche, lower height, and coastal birth; these indicators were more strongly associated with BMD for premenopausal (multiple-partial R 2 = 0.21) than postmenopausal (R 2 = 0.06) women. Young-adult exposures (e.g., early first pregnancy and age at immigration) and proximal lifestyle factors (e.g., smoking, physical inactivity, vegetarian diet, and betel nut use) were also assessed as potential predictors of BMD.
Cross-sectional and Prospective Study of Exercise and Depressed Mood in the Elderly
Authors: Kritz-Silverstein Donna , Barrett-Connor Elizabeth , Corbeau Catherine 
Published: July 2002

Abstract
This study examined cross-sectional and prospective associations of exercise with depressed mood in a community-based sample of older men and women (aged 50–89 years in 1984–1987) in southern California. Regular strenuous exercise and exercise ≥3 times per week were reported; depressed mood was assessed by using the Beck Depression Inventory (BDI). After exclusion of persons with categorical depression and those rating themselves largely or extremely physically limited during the previous month, data on 932 men and 1,097 women were available for cross-sectional analysis. Exercise and depressed mood were reassessed for 404 men and 540 women in 1992–1995; these data were the focus of prospective analyses. In 1984–1987, exercise rates were high (&gt;80%), and average BDI scores were low. Cross-sectional analyses indicated that before and after adjustment for covariates, exercise was significantly associated with less depressed mood. However, prospective analyses of the 944 persons who attended both clinic visits indicated no association between baseline exercise and either follow-up BDI score (p &gt; 0.10) or change in BDI score between baseline and follow-up (p &gt; 0.10). Results confirm that exercisers have less depressed mood. However, exercise does not protect against future depressed mood for those not clinically depressed at baseline.