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Showing papers by "University of Vermont published in 2000"


Journal ArticleDOI
01 Sep 2000-Ecology
TL;DR: The analysis of presence-absence matrices with null model randomization tests has been a major source of controversy in community ecology for over two decades as mentioned in this paper, and the performance of nine null model algorithms and four co-occurrence indices with respect to Type I and Type II errors has been systematically compared.
Abstract: The analysis of presence-absence matrices with ''null model'' randomization tests has been a major source of controversy in community ecology for over two decades. In this paper, I systematically compare the performance of nine null model algorithms and four co-occurrence indices with respect to Type I and Type II errors. The nine algorithms differ in whether rows and columns are treated as fixed sums, equiprobable, or proportional. The three models that maintain fixed row sums are invulnerable to Type I errors (false positives). One of these three is a modified version of the original algorithm of E. F. Connor and D. Simberloff. Of the four co-occurrence indices, the number of checkerboard com- binations and the number of species combinations may be prone to Type II errors (false negatives), and may not reveal significant patterns in noisy data sets. L. Stone and A. Robert's checkerboard score has good power for detecting species pairs that do not co- occur together frequently, whereas D. Schluter's V ratio reveals nonrandom patterns in the row and column totals of the matrix. Degenerate matrices (matrices with empty rows or columns) do not greatly alter the outcome of null model analyses. The choice of an ap- propriate null model and index may depend on whether the data represent classic ''island lists'' of species in an archipelago or standardized ''sample lists'' of species collected with equal sampling effort. Systematic examination of a set of related null models can pinpoint how violation of the assumptions of the model contributes to nonrandom patterns.

1,529 citations


Journal ArticleDOI
TL;DR: A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion and to be considered at risk in view of age-related penetration in this disorder.
Abstract: Hereditary Hemorrhagic Telangiectasia (HHT) is easily recognized in individuals displaying the classical triad of epistaxis, telangiectasia, and a suitable family history, but the disease is more difficult to diagnosis in many patients. Serious consequences may result if visceral arteriovenous malformations, particularly in the pulmonary circulation, are unrecognized and left untreated. In spite of the identification of two of the disease-causing genes (endoglin and ALK-1), only a clinical diagnosis of HHT can be provided for the majority of individuals. On behalf of the Scientific Advisory Board of the HHT Foundation International, Inc., we present consensus clinical diagnostic criteria. The four criteria (epistaxes, telangiectasia, visceral lesions and an appropriate family history) are carefully delineated. The HHT diagnosis is definite if three criteria are present. A diagnosis of HHT cannot be established in patients with only two criteria, but should be recorded as possible or suspected to maintain a high index of clinical suspicion. If fewer than two criteria are present, HHT is unlikely, although children of affected individuals should be considered at risk in view of age-related penetration in this disorder. These criteria may be refined as molecular diagnostic tests become available in the next few years.

1,462 citations


Journal ArticleDOI
03 Mar 2000-Science
TL;DR: Structures were obtained for three intermediates in the hydroxylation reaction of camphor by P450cam with trapping techniques and cryocrystallography and reveal a network of bound water molecules that may provide the protons needed for the reaction.
Abstract: Members of the cytochrome P450 superfamily catalyze the addition of molecular oxygen to nonactivated hydrocarbons at physiological temperature-a reaction that requires high temperature to proceed in the absence of a catalyst. Structures were obtained for three intermediates in the hydroxylation reaction of camphor by P450cam with trapping techniques and cryocrystallography. The structure of the ferrous dioxygen adduct of P450cam was determined with 0.91 angstrom wavelength x-rays; irradiation with 1.5 angstrom x-rays results in breakdown of the dioxygen molecule to an intermediate that would be consistent with an oxyferryl species. The structures show conformational changes in several important residues and reveal a network of bound water molecules that may provide the protons needed for the reaction.

1,211 citations


Journal ArticleDOI
TL;DR: The development of a measure of coping and involuntary stress responses in adolescence is described and correlations with both adolescents' and parents' reports of internalizing and externalizing symptoms were consistent with hypotheses.
Abstract: The development of a measure of coping and involuntary stress responses in adolescence is described. The Responses to Stress Questionnaire (RSQ) reflects a conceptual model that includes volitional coping efforts and involuntary responses to specific stressful events or specified domains of stress. The psychometric characteristics of the RSQ were examined across 4 domains of stress in 3 samples of adolescents and parent reports obtained in 2 samples. The factor structure of the RSQ was tested and replicated with an adequate degree of fit using confirmatory factor analysis across 3 stressors in 2 samples. Internal consistency and retest reliability for the 5 factors were adequate to excellent. Concurrent validity was established through correlations with another measure of coping, heart rate reactivity, and correlations of self- and parent-reports. Significant correlations with both adolescents' and parents' reports of internalizing and externalizing symptoms were consistent with hypotheses.

1,089 citations


Journal ArticleDOI
TL;DR: The incidence of CHF is high in the elderly and is related mainly to age, gender, clinical and subclinical coronary heart disease, systolic BP and inflammation, which is a leading source of morbidity and mortality in this group.

906 citations


Journal ArticleDOI
19 Oct 2000-Nature
TL;DR: It is shown that targeted deletion of the gene for the β1 subunit leads to a decrease in the calcium sensitivity of BK channels, a reduction in functional coupling of calcium sparks to BK channel activation, and increases in arterial tone and blood pressure.
Abstract: Small arteries exhibit tone, a partially contracted state that is an important determinant of blood pressure. In arterial smooth muscle cells, intracellular calcium paradoxically controls both contraction and relaxation. The mechanisms by which calcium can differentially regulate diverse physiological responses within a single cell remain unresolved. Calcium-dependent relaxation is mediated by local calcium release from the sarcoplasmic reticulum. These 'calcium sparks' activate calcium-dependent potassium (BK) channels comprised of alpha and beta1 subunits. Here we show that targeted deletion of the gene for the beta1 subunit leads to a decrease in the calcium sensitivity of BK channels, a reduction in functional coupling of calcium sparks to BK channel activation, and increases in arterial tone and blood pressure. The beta1 subunit of the BK channel, by tuning the channel's calcium sensitivity, is a key molecular component in translating calcium signals to the central physiological function of vasoregulation.

775 citations


Journal ArticleDOI
TL;DR: The most commonly studied genotoxicity endpoints have been selected for inclusion in this document and they are structural and numerical chromosomal aberrations assessed using cytogenetic methods (classical chromosomal aberration analysis (CA), fluorescence in situ hybridisation (FISH), micronuclei (MN), DNA damage (adducts, strand breaks, crosslinking, alkali-labile sites) assessed using bio-chemical/electrophoretic assays or sister chromatid exchanges (SCE); protein adducts; and hypoxanthine-
Abstract: The purpose of these guidelines is to provide concise guidance on the planning, performing and interpretation of studies to monitor groups or individuals exposed to genotoxic agents. Most human carcinogens are genotoxic but not all genotoxic agents have been shown to be carcinogenic in humans. Although the main interest in these studies is due to the association of genotoxicity with carcinogenicity, there is also an inherent interest in monitoring human genotoxicity independently of cancer as an endpoint. The most often studied genotoxicity endpoints have been selected for inclusion in this document and they are structural and numerical chromosomal aberrations assessed using cytogenetic methods (classical chromosomal aberration analysis (CA), fluorescence in situ hybridisation (FISH), micronuclei (MN)); DNA damage (adducts, strand breaks, crosslinking, alkali-labile sites) assessed using bio-chemical/electrophoretic assays or sister chromatid exchanges (SCE); protein adducts; and hypoxanthine-guanine phosphoribosyltransferase (HPRT) mutations. The document does not consider germ cells or gene mutation assays other than HPRT or markers of oxidative stress, which have been applied on a more limited scale.

756 citations


Journal ArticleDOI
TL;DR: The system described in this article provides low-cost, standardized assessment and documentation of certain types of behavioral problems, such as those ascribed to attention deficit hyperactivity disorder (ADHD), and requires little effort by the physician.
Abstract: 1. Thomas M. Achenbach, PhD* 2. Thomas M. Ruffle, MD† 1. 2. *Departments of Psychiatry and Psychology, University of Vermont, Burlington, VT. 3. 4. †Vermont Child Development Clinic, Burlington, VT. After completing this article, readers should be able to: 1. List the types of behavioral and emotional problems that primary care physicians who work with children must address. 2. Describe the data required from parents, children, teachers, and child care practitioners for assessment of behavioral and emotional problems. 3. Describe systems of questionnaires that can be used for obtaining standardized assessment data. Primary care physicians who work with children must deal with a great variety of behavioral and emotional problems. The system described in this article provides low-cost, standardized assessment and documentation of such problems and requires little effort by the physician. Primary care physicians are under increasing pressure to obtain standardized documentation for the conditions they encounter. The most obvious pressures stem from managed care. Among the most frequently imposed expectations of primary care physicians are to: Be gatekeepers for most forms of care needed by patients. Offer increasingly diverse services to more patients while limiting the time spent with each patient. Provide extensive documentation for assessments of patients and for treatment and referral. To fulfill these expectations, physicians need cost-effective procedures for obtaining, using, and transmitting information about patients. Children’s behavioral and emotional problems pose special challenges for meeting such managed care requirements. Certain types of behavioral problems, such as those ascribed to attention deficit hyperactivity disorder (ADHD), are widely publicized as candidates for medical management. Concerned parents, therefore, may request that pediatricians and family practitioners evaluate their children for ADHD. To assess ADHD and other behavioral and emotional problems, physicians need information from people who see children in their everyday contexts. Parents and parent-surrogates are the primary sources of such information for most children. Older children can contribute useful information about their own functioning. Teachers are especially important sources of information when children’s functioning in school is relevant, such as …

738 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the association between intrauterine growth restriction and adverse neonatal outcomes in a population of 19,759 singleton very-low-birth-weight neonates without major birth defects.

720 citations


Journal ArticleDOI
TL;DR: KPCs contain unique structural features that are susceptible to oxidative modification, and are a logical candidate for redox modification by oxidants and antioxidants that may in part determine their cancer-promoting and anticancer activities, respectively.

667 citations


Journal ArticleDOI
TL;DR: The structure of out-of-sample tests is explained, guidelines for implementing these tests are provided, and the adequacy of out of-offer tests in forecasting software is evaluated.

Journal ArticleDOI
TL;DR: Recent insights are addressed into the NF-kappaB signaling cascades that are triggered by proinflammatory cytokines such as TNF-alpha and IL-1beta and how redox regulation of NF- kappaB activation is likely to involve multiple subcellular compartments.

Reference EntryDOI
TL;DR: There is little evidence that anxiolytics aid smoking cessation, and it is not clear whether these effects are specific for individual drugs, or a class effect.
Abstract: Background There are two reasons to believe antidepressants and anxiolytics might help in smoking. First, anxiety and depression are symptoms of nicotine withdrawal, and smoking cessation sometimes precipitates depression. Second, smoking appears to be due, in part, to deficits in dopamine, serotonin and norepinephrine, all of which are increased by anxiolytics and antidepressants. Objectives The aim of this review is to assess the effectiveness of such drugs in aiding long term smoking cessation. The drugs include bupropion; buspirone; diazepam; doxepin; fluoxetine; imipramine; meprobamate; moclobemide; nortriptyline; tryptophan; ondansetron; venlafaxine and the beta-blockers metoprolol, oxprenolol and propanolol. Search strategy We searched the Cochrane Tobacco Addiction Group trials register which includes trials indexed in Medline, Embase, SciSearch and PsycLit, and meetings abstracts. Selection criteria We considered randomized trials comparing anxiolytic or antidepressant drugs to placebo or an alternative therapeutic control for smoking cessation. We excluded trials with less than 6 months follow-up. Data collection and analysis We extracted data in duplicate on the type of study population, the nature of the drug therapy, the outcome measures, method of randomisation, and completeness of follow-up. The main outcome measure was abstinence from smoking after at least six months follow-up in patients smoking at baseline. We used the most rigorous definition of abstinence for each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed effects model. Main results There was one trial each of the anxiolytics diazepam, meprobamate, metoprolol and oxprenolol. There were two trials of the anxiolytic buspirone. None of these showed evidence of effectiveness in helping smokers to quit. There was one trial each of the antidepressants fluoxetine and moclobemide, two of nortriptyline, and four trials of bupropion. Nortriptyline and bupropion increased cessation and other antidepressants might also be effective. One trial found combined bupropion and nicotine patch produced higher quit rates than patch alone. Reviewer's conclusions There is little evidence that anxiolytics aid smoking cessation. Some antidepressants (bupropion and nortriptyline) can aid smoking cessation. It is not clear whether these effects are specific for individual drugs, or a class effect.

Book ChapterDOI
01 Jan 2000

Journal ArticleDOI
TL;DR: It is proposed that frequency and amplitude modulation of Ca(2+) sparks by contractile and relaxant agents is an important mechanism to regulate smooth muscle function.
Abstract: Local intracellular Ca(2+) transients, termed Ca(2+) sparks, are caused by the coordinated opening of a cluster of ryanodine-sensitive Ca(2+) release channels in the sarcoplasmic reticulum of smooth muscle cells. Ca(2+) sparks are activated by Ca(2+) entry through dihydropyridine-sensitive voltage-dependent Ca(2+) channels, although the precise mechanisms of communication of Ca(2+) entry to Ca(2+) spark activation are not clear in smooth muscle. Ca(2+) sparks act as a positive-feedback element to increase smooth muscle contractility, directly by contributing to the global cytoplasmic Ca(2+) concentration ([Ca(2+)]) and indirectly by increasing Ca(2+) entry through membrane potential depolarization, caused by activation of Ca(2+) spark-activated Cl(-) channels. Ca(2+) sparks also have a profound negative-feedback effect on contractility by decreasing Ca(2+) entry through membrane potential hyperpolarization, caused by activation of large-conductance, Ca(2+)-sensitive K(+) channels. In this review, the roles of Ca(2+) sparks in positive- and negative-feedback regulation of smooth muscle function are explored. We also propose that frequency and amplitude modulation of Ca(2+) sparks by contractile and relaxant agents is an important mechanism to regulate smooth muscle function.

Journal ArticleDOI
01 Oct 2000-Chest
TL;DR: A panel of the American College of Chest Physicians developed a clinical practice guideline on the medical and surgical treatment of parapneumonic effusions (PPE) using evidence-based methods as mentioned in this paper.

Journal ArticleDOI
TL;DR: Evidence is provided that FLIP is not simply an inhibitor of death-receptor-induced apoptosis but that it also mediates the activation of NF-kappaB and Erk by virtue of its capacity to recruit adaptor proteins involved in these signaling pathways.

Journal ArticleDOI
TL;DR: Among elderly Americans, depressive symptoms constitute an independent risk factor for the development of CHD and total mortality.
Abstract: Background—Several epidemiological studies have associated depressive symptoms with cardiovascular disease. We investigated whether depressive symptoms constituted a risk for coronary heart disease (CHD) and total mortality among an apparently healthy elderly cohort. Methods and Results—In a prospective cohort of 5888 elderly Americans (≥65 years) who were enrolled in the Cardiovascular Health Study, 4493 participants who were free of cardiovascular disease at baseline provided annual information on their depressive status, which was assessed using the Depression Scale of the Center for Epidemiological Studies. These 4493 subjects were followed for 6 years for the development of CHD and mortality. The cumulative mean depression score was assessed for each participant up to the time of event (maximum 6-year follow-up). Using time-dependent, proportional-hazards models, the unadjusted hazard ratio associated with every 5-unit increase in mean depression score for the development of CHD was 1.15 (P=0.006); t...

Journal ArticleDOI
TL;DR: This article investigated empirically the determinants of economic growth for a set of semi-industrialized export-oriented economies in which women provided the bulk of labor in the export sector and found that gender inequality which contributes to women's relatively lower wages was a stimulus to growth via the effect on exports during 1975-95.

Journal ArticleDOI
TL;DR: Successful nonoperative management was associated with higher blood pressure and hematocrit, and less severe injury based on ISS, Glasgow Coma Scale, grade of splenic injury, and quantity of hemoperitoneum.
Abstract: Background: Nonoperative management of blunt injury to the spleen in adults has been applied with increasing frequency. However, the criteria for nonoperative management are controversial. The purpose of this multi-institutional study was to determine which factors predict successful observation of blunt splenic injury in adults. Methods: A total of 1,488 adults (>15 years of age) with blunt splenic injury from 27 trauma centers in 1997 were studied through the Multi-institutional Trials Committee of the Eastern Association for the Surgery of Trauma. Statistical analysis was performed with analysis of variance and extended X 2 test. Data are expressed as mean ± SD; a value of p 15 were successfully observed. Frequency of immediate operation correlated with American Association for the Surgery of Trauma (AAST) grades of splenic injury: I (23.9%), II (22.4%), III (38.1%), IV (73.7%), and V (94.9%) (p < 0.05). Of patients initially managed nonoperatively, the failure rate increased significantly by AAST grade of splenic injury: I (4.8%), II (9.5%), III (19.6%), IV (33.3%), and V (75.0%) (p < 0.05). A total of 60.9% of the patients failed nonoperative management within 24 hours of admission; 8% failed 9 days or later after injury. Laparotomy was ultimately performed in 19.9% of patients with small hemoperitoneum, 49.4% of patients with moderate hemoperitoneum, and 72.6% of patients with large hemoperitoneum. Conclusion: In this multicenter study, 38.5% of adults with blunt splenic injury went directly to laparotomy. Ultimately, 54.8% of patients were successfully managed nonoperatively; the failure rate of planned observation was 10.8%, with 60.9% of failures occurring in the first 24 hours. Successful nonoperative management was associated with higher blood pressure and hematocrit, and less severe injury based on ISS, Glasgow Coma Scale, grade of splenic injury, and quantity of hemoperitoneum.


Journal ArticleDOI
TL;DR: Examination of radiologic imaging techniques suggests that early-postmenopausal status is associated with a preferential increase in intra-abdominal fat that is independent of age and total body fat mass.
Abstract: OBJECTIVE: Preliminary studies suggest that the menopause transition is associated with deleterious changes in body composition and abdominal fat distribution. Limitations of the methodology used in these studies, however, render their conclusions controversial. Thus, the present study used radiologic imaging techniques to examine the effect of menopausal status on body composition and abdominal fat distribution. DESIGN: Cross-sectional. SUBJECTS: Fifty-three healthy, middle-aged, premenopausal women (mean±SD; 47±3 y) and 28 early-postmenopausal women (51±4 y). MEASUREMENTS: Total and regional body composition by dual energy X-ray absorptiometry and abdominal fat distribution by computed tomography. RESULTS: No differences in total body fat-free mass or appendicular skeletal muscle mass were noted between groups. In contrast, total body fat mass was 28% higher (23±7 vs 18±7 kg) and percentage fat 17% higher (35±6 vs 30±9%; both P<0.01) in postmenopausal women compared with premenopausal women. Postmenopausal women had a 49% greater intra-abdominal (88±32 vs 59±32 cm2; P<0.01) and a 22% greater abdominal subcutaneous fat area (277±93 vs 227±108 cm2; P<0.05) compared to premenopausal women. The menopause-related difference in intra-abdominal fat persisted (P<0.05) after statistical adjustment for age and total body fat mass, whereas no difference in abdominal subcutaneous fat was noted. A similar pattern of differences in total and abdominal adiposity was noted in sub-samples of pre- and postmenopausal women matched for age or fat mass. CONCLUSION: Our data suggest that early-postmenopausal status is associated with a preferential increase in intra-abdominal fat that is independent of age and total body fat mass.

Journal ArticleDOI
TL;DR: The authors conclude that should hemostatic variables be shown to contribute to IRS-related cardiovascular disease, apart from plasminogen activator inhibitor-1, they may do so independently of the established metabolic abnormalities.
Abstract: The known metabolic cardiovascular disease risk factors associated with insulin resistance syndrome (IRS) do not adequately explain the excess cardiovascular disease risk attributed to this syndrome, and abnormalities in hemostatic variables may contribute to this excess risk. Using data from 322 nondiabetic elderly men and women (aged 65-100 years) participating in the Cardiovascular Health Study during 1989-1990, the authors performed factor analysis on 10 metabolic risk factors associated with IRS and 11 procoagulation, inflammation, and fibrinolysis variables to examine the clustering of the metabolic and hemostatic risk markers. Factor analysis of the metabolic variables confirmed four uncorrelated factors: body mass, insulin/glucose, lipids, and blood pressure. Adding the hemostatic variables yielded three new factors interpreted as inflammation, vitamin K-dependent proteins, and procoagulant activity. Plasminogen activator inhibitor-1 clustered with the body mass factor, supporting the hypothesis that obesity is related to impaired fibrinolysis. Fibrinogen clustered with the inflammation summary factor rather than procoagulant activity, supporting the position that fibrinogen principally reflects underlying inflammation rather than procoagulant potential. The authors conclude that should hemostatic variables be shown to contribute to IRS-related cardiovascular disease, apart from plasminogen activator inhibitor-1, they may do so independently of the established metabolic abnormalities. Am J Epidemiol 2000;152:897-907.

Journal ArticleDOI
01 Dec 2000-Immunity
TL;DR: A novel function of IL-6 is described: the negative regulation of CD4+ Th1 cell differentiation, which promotes CD 4+ Th2 differentiation and inhibits Th1 differentiation by two independent molecular mechanisms.

Journal ArticleDOI
TL;DR: It is indicated that long-term alendronate treatment is well tolerated and effective for 7 yr, and increases in spinal BMD continue for at least 7 years, and other skeletal benefits are maintained.
Abstract: We report here the second 2-yr extension of a clinical trial among postmenopausal women; 235 women continued blinded treatment with 5 or 10 mg alendronate daily, and 115 women who had been treated with alendronate for 5 yr were switched to blinded placebo. Continuous treatment with alendronate (10 mg daily) for 7 yr increased lumbar spine bone mineral density (BMD) by 11.4% compared to baseline. After the initial 18 months, each additional year of treatment through yr 7 increased spine BMD by 0.8% for the 10-mg dose and 0.6% for the 5-mg dose, with significant increases during yr 6-7. Previously reported increases in BMD at other skeletal sites and decreases in biochemical markers of bone turnover remained stable during yr 6-7. Among women previously taking alendronate for 5 yr who were switched to placebo, there was no significant decline in BMD at the spine or hip, whereas small, but significant, decreases in BMD at the forearm and total body and small increases in biochemical markers were observed. The safety and tolerability profiles were similar to those of placebo. This is the largest published long-term study of antiresorptive therapy. Our findings indicate that long-term alendronate treatment is well tolerated and effective for 7 yr. Increases in spinal BMD continue for at least 7 yr, and other skeletal benefits are maintained. Discontinuation does not lead to accelerated bone loss, but continuous treatment yields better skeletal benefits than shorter treatment.

Journal Article
TL;DR: Transscleral delivery of immunoglobulins and other large compounds to the choroid and retina may be feasible and large molecules, such as IgG, diffuse across sclera in a manner consistent with porous diffusion through a fiber matrix.
Abstract: Purpose To determine the in vitro permeability of the sclera to high molecular weight compounds and the relationship between scleral permeability and molecular size. Methods Fresh rabbit sclera was mounted in a two-chamber diffusion apparatus, and its permeability to sodium fluorescein, fluorescein isothiocyanate (FITC)-conjugated bovine serum albumin, FITC-IgG, and FITC dextrans ranging in molecular weight from 4 to 150 kDa was determined by fluorescence spectrophotometry. Electron microscopy was used to assess the impact of the experimental design on scleral ultrastructural integrity. The effect of the diffusion apparatus on scleral hydration was examined. Rabbit scleral permeability was compared with previously reported data for human and bovine sclera. Results Scleral permeability decreased with increasing molecular weight and molecular radius, consistent with previous human and bovine data. Molecular radius was a better predictor of scleral permeability than molecular weight. The sclera was more permeable to globular proteins than to linear dextrans of similar molecular weight. The experimental apparatus did not alter scleral ultrastructure. Permeability of rabbit sclera was similar to human sclera but greater than bovine sclera. Conclusions Large molecules, such as IgG, diffuse across sclera in a manner consistent with porous diffusion through a fiber matrix. Transscleral delivery of immunoglobulins and other large compounds to the choroid and retina may be feasible.

Journal ArticleDOI
TL;DR: An association of CRP and fibrinogen with urinary albumin excretion in the micro Albuminuric range in type 2 diabetic and nondiabetic individuals is shown and chronic inflammation emerges as a potential mediator between microalbuminuria and macrovascular disease.

Journal ArticleDOI
TL;DR: HRT and raloxifene lower serum homocysteine levels to a comparable extent in postmenopausal women, and the relationship between elevated C-reactive protein levels with HRT and cardiovascular disease events requires further study.
Abstract: C-Reactive protein and homocysteine are independent risk factors for the development of cardiovascular disease. This study compared the effects of hormone replacement therapy (HRT) and raloxifene on serum C-reactive protein and homocysteine levels as markers of cardiovascular risk in healthy postmenopausal women. Healthy postmenopausal women (n = 390) were enrolled in a double blind, randomized, placebo-controlled, 6-month trial at eight out-patient sites in the United States. Women were randomly assigned to receive continuous combined HRT (0.625 mg/day conjugated equine estrogen and 2.5 mg/day medroxyprogesterone acetate), raloxifene (60 or 120 mg/day), or placebo for 6 months. C-Reactive protein and homocysteine were measured in baseline and 6-month serum samples. HRT increased C-reactive protein levels by 84% (P 0.2). Raloxifene (60 and 120 mg/day) significantly lowered serum levels of homocystein...

Journal ArticleDOI
TL;DR: It is demonstrated that species richness and species density can generate opposite patterns of community response to disturbance, which provides some support for Huston’s dynamic-equilibrium model but does not support the intermediate-disturbance hypothesis.
Abstract: Disturbance frequency, intensity, and areal extent may influence the effects of disturbance on biological communities. Furthermore, these three factors may have interacting effects on biological diversity. We manipulated the frequency, intensity, and area of disturbance in a full-factorial design on artificial substrates and measured responses of benthic macroinvertebrates in a northern Vermont stream. Macroinvertebrate abundance was lower in all disturbance treatments than in the undisturbed control. As in most other studies in streams, species density (number of species/sample) was lower in disturbed treatments than in undisturbed controls. However, species density is very sensitive to total abundance of a sample, which is usually reduced by disturbance. We used a rarefaction method to compare species richness based on an equivalent number of individuals. In rarefied samples, species richness was higher in all eight disturbed treatments than in the undisturbed control, with significant increases in species richness for larger areas and greater intensities of disturbance. Increases in species richness in response to disturbance were consistent within patches, among patches with similar disturbance histories, and among patches with differing disturbance histories. These results provide some support for Huston’s dynamic-equilibrium model but do not support the intermediate-disturbance hypothesis. Our analyses demonstrate that species richness and species density can generate opposite patterns of community response to disturbance. The interplay of abundance, species richness, and species density has been neglected in previous tests of disturbance models.

Journal ArticleDOI
TL;DR: Examination of the effects of a 6-month randomized program of endurance training, resistance training, or control conditions on insulin sensitivity in nonobese, younger women concludes that enhanced glucose uptake after physical training in young women occurs with and without changes in FFM and body composition.
Abstract: We examined the effects of a 6-month randomized program of endurance training (n = 14), resistance training (n = 17), or control conditions (n = 20) on insulin sensitivity in nonobese, younger women (18-35 yr). To examine the possible mechanism(s) related to alterations in insulin sensitivity, we measured body composition, regional adiposity, and skeletal muscle characteristics with computed tomography. We observed no changes in total body fat, sc abdominal adipose tissue, or visceral adipose tissue with endurance or resistance training. Insulin sensitivity, however, increased with endurance training (pre, 421 +/- 107; post, 490 +/- 133 mg/min; P < 0.05) and resistance training (pre, 382 +/- 87; post, 417 +/- 89 mg/min; P = 0.06). When the glucose disposal rate was expressed per kg fat-free mass (FFM), the improved insulin sensitivity persisted in endurance-trained (pre, 10.5 +/- 2.7; post, 12.1 +/- 3.3 mg/min x kg FFM; P < 0.05), but not in resistance-trained (pre, 9.7 +/- 1.9; post, 10.2 +/- 1.8 mg/min x kg FFM; P = NS) women. Muscle attenuation ratios increased (P < 0.05) in both endurance- and resistance-trained individuals, but this was not related to changes in insulin sensitivity. Moreover, the change in insulin sensitivity was not related to the increased maximum aerobic capacity in endurance-trained women (r = 0.24; P = NS). We suggest that both endurance and resistance training improve glucose disposal, although by different mechanisms, in young women. An increase in the amount of FFM from resistance training contributes to increased glucose disposal probably from a mass effect, without altering the intrinsic capacity of the muscle to respond to insulin. On the other hand, endurance training enhances glucose disposal independent of changes in FFM or maximum aerobic capacity, suggestive of an intrinsic change in the muscle to metabolize glucose. We conclude that enhanced glucose uptake after physical training in young women occurs with and without changes in FFM and body composition.