Carbonyl- and carboxyl-substituted enediynes: synthesis, computations, and thermal reactivity.

The influence of electron-withdrawing groups (carbonyl and carboxyl) at the alkyne termini on the reactivity of enediynes was investigated by a combination of experimental and computational techniques. While the general chemical reactivity of such enediynes, especially if non-benzannelated, is increased markedly, the thermal cyclization, giving rise to Bergman cyclization products, is changed little relative to the parent enediyne system. This is evident from kinetic measurements and from density functional theory (DFT, BLYP/6-31G + thermal corrections) computations of the experimental systems which show that the Bergman cyclization barriers slightly (3-4 kcal/mol) increase, in contrast to earlier theoretical predictions.

Older women with diabetes have an increased risk of fracture: a prospective study.

To determine whether type 2 diabetes is associated with fracture in older women, we analyzed data from 9654 women, age 65 yr or older, in the Study of Osteoporotic Fractures. Diabetes with age at onset 40 yr or older was reported by 657 women, of whom 106 used insulin. A total of 2624 women experienced at least one nonvertebral fracture during an average follow-up of 9.

Independent and interactive effects of apolipoprotein E phenotype and cardiorespiratory fitness on plasma lipids.

Purpose: To examine whether the association Apolipoprotein E (Apo E) phenotype with plasma lipids is influenced by physical fitness level. Also, to explore the interactive and independent relative contributions of Apo E phenotype, fitness (or physical activity), and other modifiable factors to variation in plasma low density lipoprotein (LDL-C) and high density lipoprotein (HDL-C) levels at baseline and over a seven-year follow-up.

Methods: Physical fitness (duration of a graded treadmill test), Apo E phenotype, plasma LDL-C and HDL-C, and covariates were measured at baseline and seven years later in a bi-racial cohort of young adults, aged 18-30 years at baseline in 1985-86, from the Coronary Artery Risk Development In Young Adults (CARDIA) study.

Association of ventricular premature complexes with electrocardiographic-estimated left ventricular mass in a population of African-American and white men and women (The Atherosclerosis Risk in Communities.

Increased left ventricular (LV) mass is often found in adults and is a powerful predictor of cardiovascular mortality. To test the hypothesis that an electrocardiographic estimate of LV mass--the Cornell voltage--is associated with ventricular premature complexes (VPCs) in free-living adults, a cross-sectional analysis of the predictors of VPCs on a 2-minute rhythm strip in a population-based sample of 13,606 middle-aged, African-American and white men and women from 4 US communities in the Atherosclerosis Risk in Communities Study baseline examinations was performed. In adults without known coronary artery disease, the prevalence of VPCs increases monotonically with increasd Cornell voltages within ethnicity and gender groups.

Changes in US health care access in the 90s: race and income differences from the CARDIA Study. Coronary Artery Risk Development in Young Adults.

Objective: Health care financing is changing rapidly in the United States. We investigated whether and how health care access is changing concurrently with changes in financing, with special attention to a minority population.

Methods: We examined a longitudinal biracial (half African-American, half White) urban cohort of 3,565 individuals, aged 25-37 years old, in 1992-93 and again in 1995-96.

Associations of fat distribution and obesity with hypertension in a bi-ethnic population: the ARIC study. Atherosclerosis Risk in Communities Study.

Objective: To examine associations of hypertension with obesity and fat distribution among African American and white men and women.

Research Methods And Procedures: The analysis sample included 15,063 African American and white men and women between the ages of 45 and 64 years who were participants in the 1987 through 1989 examination of the Atherosclerosis Risk in Communities Study (ARIC). Odds ratios and adjusted prevalences of hypertension were calculated across sex-specific quintiles of body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, and waist-to-height ratio (waist/ height) and adjusted for age, research center, smoking, education, physical activity, alcohol consumption, hormone replacement therapy, and menopausal status.

[Ethical aspects of health care economy].

One of the present-day problems which illustrates several ethical issues is the development of health care, generally referred to as health policy. For over 25 years there has been a debate relating to runaway costs in health care. This led to various retrenchment attempts which failed altogether and will probably continue to fail in the future unless there is a radical change in approaching the subject.

Kinetic isotope effects for the C-H activation step in phase-transfer halogenations of alkanes.

Within the scope of phase-transfer halogenations (Br and I) of alkanes, significant H/D kinetic isotope effects (KIE = 4-5) indicate that hydrogen abstraction is rate limiting. The excellent agreement of computed and experimentally determined H/D KIE as well as trapping experiments support the involvement of trihalomethyl radicals in the activation step.

The Family Risk Score for coronary heart disease: associations with lipids, lipoproteins, and body habitus in a middle-aged bi-racial cohort: The ARIC study.

Purpose: To examine the association between the Family Risk Score (FRS) for coronary heart disease (CHD) and body mass index (BMI), waist-to-hip ratio (WHR), high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol, triglycerides, and lipoprotein(a) protein [Lp(a)].

Methods: FRS was computed from observed and expected CHD events using family data collected from 11467 black and white adults of the Atherosclerosis Risk in Communities Study (ARIC). BMI, WHR, and lipids adjusted for study center, race, education, BMI (except BMI), WHR (except for BMI and WHR), cigarette smoking, alcohol, and Keys' score were compared among low (FRS < -0.

Weight gain continues in the 1990s: 10-year trends in weight and overweight from the CARDIA study. Coronary Artery Risk Development in Young Adults.

The prevalence of obesity increased in the United States through the 1980s. The authors examined 10-year aging and secular (time-related) trends in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort for indications of whether these trends are continuing and for ages of peak weight gain in young adults. CARDIA is a population-based, prospective study of 5,115 African-American and White men and women aged 18-30 years at baseline.

Body size and risk for clinical fractures in older women. Study of Osteoporotic Fractures Research Group.

Background: Small body size predicts hip fractures in older women.

Objective: To test the hypothesis that small body size predicts the risk for other clinical fractures.

Design: Prospective cohort study.

A valence bond study of the Bergman cyclization: geometric features, resonance energy, and nucleus-independent chemical shift (NICS) values.

The Bergman cyclization of (Z)-hex-3-ene-1,5-diynes (1, enediynes), which produces pharmacologically important DNA-cleaving biradicals (1,4-benzyne, 2), was studied by using Hartree-Fock (HF) and density-functional theory (DFT) based valence bond (VB) methods (VB-HF and VB-DFT, respectively). We found that only three VB configurations are needed to arrive at results not too far from complete active space [CASSCF(6 x 6)] computations, while the quality of VB-DTF utilizing the same three configurations improves upon CASSCF(6 x 6) analogous to CASPT2. The dominant VB configuration in 1 contributes little to 2, while the most important biradical configuration in 2 plays a negligible role in 1.

Which electron count rules are needed for four-center three-dimensional aromaticity?

A series of charged and neutral four-center n-electron (4c-ne, n = 1-4) molecules based on the adamantane framework, but which include combinations of boron, nitrogen, and phosphorus atoms at bridgehead positions, were studied computationally at the B3LYP/6-31G* level of density functional theory (DFT). The three-dimensional aromaticity, observed earlier for the 1,3,5,7-bisdehydroadamantane dication (1), is found to be general for 4c-2e electron systems. The degree of electron delocalization, evaluated by energetic, geometric, and various magnetic criteria, is quite independent of the molecular symmetry (point groups vary from Td to Cs), the degeneracy of the orbitals, the molecular charges, and the nature of the atoms participating in the delocalized bonding.

Blood pressure and menopausal transition: the Atherosclerosis Risk in Communities study (1987-95).

Objective: Blood pressure changes during menopausal transition have not been studied previously using a biracial sample. We investigated whether menopausal transition was associated with change in blood pressure in African-American or white women.

Design, Setting And Participants: The prospective multicenter study, the Atherosclerosis Risk In Communities (ARIC) Study (1987-95) was utilized.

Early adopters of olestra-containing foods: who are they?

Objective: To identify the characteristics of people consuming olestra-containing foods when first introduced at a test-marketing site.

Design: Data are from the Olestra Postmarketing Surveillance Study (OPMSS). After the introduction of olestra into a large test-marketing site, study participants received 3 follow-up telephone calls, at 3-month intervals, in which they were questioned about their diets during the previous month.

Physical activity and body weight: associations over ten years in the CARDIA study. Coronary Artery Risk Development in Young Adults.

Background: Hypothesis 1--sustained changes in physical activity are inversely related to changes in body weight. Hypothesis 2-those who attenuate weight gain because of a temporary increase in physical activity (PA) may maintain a lower body weight over time.

Methods: Data were from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a cohort of black and white men and women, aged 18-30y at baseline, who attended up to five examinations over a 10y period (n=5,115 at baseline).

The First Enantiomerically Pure Triangulane (M)-Trispiro.

A remarkably high specific rotation, even at 589 nm, is shown by (M)-1, the first enantiomerically pure unbranched [4]triangulane, although it has no chromophore that would lead to any significant absorption above 200 nm. This outstanding rotatory power is in line with a helical arrangement of its sigma bonds, as confirmed by high-level computations. Thus, it is appropriate to call (M)-1 a "sigma-[4]helicene", the first sigma-bond analogue of the aromatic [n]helicenes.

The First Efficient Iodination of Unactivated Aliphatic Hydrocarbons.

No heavy metals, no enzymes, and a simple protocol: the direct iodination of aliphatic hydrocarbons, which has not been possible to date, can now be carried out in multiphase systems [see for example Eq. (1)]. In situ generated tetraiodomethane serves as a key intermediate in this selective radical chain reaction initiated by a single electron transfer.

The relationship between lipids/lipoproteins and atherosclerosis in African Americans and whites: the Atherosclerosis Risk in Communities Study.

Purpose: The relationships between lipids/lipoproteins and atherosclerosis were determined in African Americans and whites to assess the consistency of the relationship between these two groups. Differences could suggest varying biological, environmental, or life-style cofactors influencing development of atherosclerosis.

Methods: In the Atherosclerosis Risk in Communities Study, 2966 African Americans and 9399 whites had determinations of LDL, HDL, HDL2, and HDL3 cholesterol, triglycerides, apolipoprotein A1 and B, and lipoprotein (a).

Serum leptin and weight gain over 8 years in African American and Caucasian young adults.

Objective: There is considerable interest in how to prevent weight gain in adulthood. Leptin, a peptide hormone expressed in adipose tissue, is believed to signal the central nervous system about the level of body fat stores, and thereby may control appetite. Little information exists on whether the serum leptin concentration influences long-term weight changes in the free-living population.

Prevalence of binge eating disorder, obesity, and depression in a biracial cohort of young adults.

This article examined the prevalence of binge eating disorder (BED), obesity, and depressive symptomatology in a biracial, population-based cohort of men and women participating in a longitudinal study of cardiovascular risk factor development. The Revised Questionnaire on Eating and Weight Patterns was used to establish BED status among the 3,948 (55% women, 48% Black) participants (age 28-40 years). Body mass index (BMI: kg/m2) was used to define overweight (BMI > or = 27.

Seven-year changes in physical fitness, physical activity, and lipid profile in the CARDIA study. Coronary Artery Risk Development in Young Adults.

Purpose: To relate seven year changes in physical fitness and physical activity in the young adult population to changes in the plasma lipid profile and to examine the influence of weight change on those relationships.

Methods: The participants in this observational study were the 1777 black and white men and women, ages 18-30 at entry into the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, who completed a symptom-limited graded treadmill exercise test and had an overnight fasting blood draw at both the Baseline (1985-86) and Year 7 (1992-93) exams. CARDIA, a longitudinal study of the relationships of lifestyle and physiological variables to the development of coronary heart disease risk factors, consists of population-based cohorts in Birmingham, Alabama, Minneapolis, Minnesota and Chicago, Illinois and a cohort recruited from the membership of a large, pre-paid health care plan, broadly representative of the population, in Oakland, California.