Effect of heavy strength training on thigh muscle cross-sectional area, performance determinants, and performance in well-trained cyclists

The purpose of this study was to investigate the effect of heavy strength training on thigh muscle cross-sectional area (CSA), determinants of cycling performance, and cycling performance in well-trained cyclists. Twenty well-trained cyclists were assigned to either usual endurance training combined with heavy strength training [E + S; n = 11 (♂ = 11)] or to usual endurance training only [E; n = 9 (♂ = 7, ♀ = 2)]. The strength training performed by E + S consisted of four lower body exercises [3 × 4–10 repetition maximum (RM)], which were performed twice a week for 12 weeks. Thigh muscle CSA, maximal force in isometric half squat, power output in 30 s Wingate test, maximal oxygen consumption (VO_2max), power output at 2 mmol l⁻¹ blood lactate concentration ([la⁻]), and performance, as mean power production, in a 40-min all-out trial were measured before and after the intervention. E + S increased thigh muscle CSA, maximal isometric force, and peak power in the Wingate test more than E. Power output at 2 mmol l⁻¹ [la⁻] and mean power output in the 40-min all-out trial were improved in E + S (P < 0.05). For E, only performance in the 40-min all-out trial tended to improve (P = 0.057). The two groups showed similar increases in VO_2max (P < 0.05). In conclusion, adding strength training to usual endurance training improved determinants of cycling performance as well as performance in well-trained cyclists. Of particular note is that the added strength training increased thigh muscle CSA without causing an increase in body mass.     

In-season strength maintenance training increases well-trained cyclists’ performance

We investigated the effects of strength maintenance training on thigh muscle cross-sectional area (CSA), leg strength, determinants of cycling performance, and cycling performance. Well-trained cyclists completed either (1) usual endurance training supplemented with heavy strength training twice a week during a 12-week preparatory period followed by strength maintenance training once a week during the first 13 weeks of a competition period (E + S; n = 6 [♂ = 6]), or (2) usual endurance training during the whole intervention period (E; n = 6 [♂ = 5, ♀ = 1]). Following the preparatory period, E + S increased thigh muscle CSA and 1RM (p < 0.05), while no changes were observed in E. Both groups increased maximal oxygen consumption and mean power output in the 40-min all-out trial (p < 0.05). At 13 weeks into the competition period, E + S had preserved the increase in CSA and strength from the preparatory period. From the beginning of the preparatory period to 13 weeks into the competition period, E + S increased peak power output in the Wingate test, power output at 2 mmol l⁻¹ [la⁻], maximal aerobic power output (W _max), and mean power output in the 40-min all-out trial (p < 0.05). The relative improvements in the last two measurements were larger than in E (p < 0.05). For E, W _max and power output at 2 mmol l⁻¹ [la⁻] remained unchanged. In conclusion, in well-trained cyclists, strength maintenance training in a competition period preserved increases in thigh muscle CSA and leg strength attained in a preceding preparatory period and further improved cycling performance determinants and performance.     

Differential in vivo clearance and response to secondary heterologous infections by H2(b)-restricted dengue virus-specific CD8+ T cells

Cytotoxic T lymphocytes (CTL) are hypothesized to play a role in clearance during primary dengue virus (DENV) infections, and contribute to immunopathology during secondary heterologous infections in humans. We previously reported skewed T-cell responses to secondary DENV infection in BALB/c (H-2(d)) mice, reproducing characteristics of human DENV infection. To set the stage for using widely available transgenic and knockout mice, we extended these studies to identify DENV-specific T-cell responses in C57BL/6 (H-2(b)) mice. We identified dominant CD8+ T-cell responses to H-2D(b)-restricted epitopes on the DENV NS4a (aa 249-265) and NS5 (aa 521-537) proteins. High frequencies of IFN-γ- and TNF-α-producing T cells directed at both epitopes were detected following primary infection with all four DENV serotypes, and were augmented by secondary DENV infections. In vivo cytotoxicity assays demonstrated rapid clearance of target cells pulsed with the NS4a peptide; in contrast, NS5 peptide-pulsed target cells were poorly cleared in vivo. These data characterize two H-2(b)-restricted T-cell epitopes displaying divergent in vivo function. These results should facilitate further studies of the in vivo effects of DENV-specific T cells, including the use of genetically modified mouse strains.     

Physical activity counseling in primary care: who has and who should be counseling?

OBJECTIVE: To examine the physical activity (PA) counseling literature in primary care in order to identify which intervention provider has been used to date and their relative effectiveness for increasing PA. METHOD: MEDLINE and PsycINFO databases were searched for PA intervention studies in primary care settings. RESULTS: Of the 19 studies, 37% were conducted solely by physicians, 37% by allied health professionals, while 26% were combined-provider interventions. There was a decline in the number of physician-only interventions and a shift towards interventions offered by allied health professionals as adjuncts or alone. Interventions across all provider categories generated some improvements in physical activity behavior, however, it appears that allied health professionals as adjuncts or alone produced the best results in the long-term (>6 months). There was substantial variation in the location and counseling approach employed by allied health professionals. CONCLUSION: We argue for an interdisciplinary model in which physicians recommend PA and provide referrals to allied health professionals such as physical activity counselors. PRACTICE IMPLICATIONS: With physical activity counselors' specialized training and greater time available to the patient, they may provide more intensive and effective counseling required for behavior change and maintenance.     

Cortical and subcortical diseases: Do true neuropsychological differences exist?

Previous work examining the cortical-subcortical distinction as it relates to cognitive patterns has not typically used genetic confirmation to identify these groups, controlled for age, or used a comprehensive battery to assess specific cognitive abilities. The present study is the first to include only genetically confirmed Familial Alzheimer's disease (FAD) and Huntington's disease (HD) patients to evaluate this distinction. Ten patients with FAD, 11 patients with HD, and 17 matched healthy individuals were compared on a comprehensive neuropsychological battery that included tasks of language, memory, attention, visual-spatial, and executive function. The only neuropsychological measures to differentiate the two clinical groups were Animal Fluency and Letter Fluency; performance on all other measures did not differ. Although the neuropsychological battery adequately distinguished between clinical and healthy individuals, it was not useful to further differentiate the cortical or subcortical nature of the disease. FAD and HD appear to have similar neuropsychological profiles; therefore the cortical versus subcortical cognitive distinction may not be clinically meaningful.     

Biofilm formation by Moraxella catarrhalis in vitro: roles of the UspA1 adhesin and the Hag hemagglutinin

Mutant analysis was used to identify Moraxella catarrhalis gene products necessary for biofilm development in a crystal violet-based assay involving 24-well tissue culture plates. The wild-type M. catarrhalis strains that formed the most extensive biofilms in this system proved to be refractory to transposon mutagenesis, so an M. catarrhalis strain was constructed that was both able to form biofilms in vitro and amenable to transposon mutagenesis. Chromosomal DNA from the biofilm-positive strain O46E was used to transform the biofilm-negative strain O35E; transformants able to form biofilms were identified and subjected to transposon-mediated mutagenesis. Biofilm-negative mutants of these transformants were shown to have a transposon insertion in the uspA1 gene. Nucleotide sequence analysis revealed that the biofilm-positive transformant T14 contained a hybrid O46E-O35E uspA1 gene, with the N-terminal 155 amino acids being derived from the O46E UspA1 protein. Transformant T14 was also shown to be unable to express the Hag protein, which normally extends from the surface of the M. catarrhalis cell. Introduction of a wild-type O35E hag gene into T14 eliminated its ability to form a biofilm. When the hybrid O46E-O35E uspA1 gene from T14 was used to replace the uspA1 gene of O35E, this transformant strain did not form a biofilm. However, inactivation of the hag gene did allow biofilm formation by strain O35E expressing the hybrid O46E-O35E uspA1 gene product. The Hag protein was shown to have an inhibitory or negative effect on biofilm formation by these M. catarrhalis strains in the crystal violet-based assay.     

CLARION: a novel interprofessional approach to health care education.

The authors describe the development and impact of CLARION, a student-run organization at the University of Minnesota founded in 2001 and dedicated to furthering interprofessional education for health professions students. CLARION's student founders recognized that three recent reports from the Institute of Medicine will fuel significant changes in health professions education. Moreover, they deduced that targeted, interprofessional education in the preclinical years could provide fundamental skills and understanding needed to make today's patient care safer and more effective. By engaging health care professionals and faculty, CLARION creates and conducts extracurricular, interprofessional experiences for students that are reflective of the six IOM aims for health care. Student members are from four separate schools of the university's academic health center: medicine, nursing, pharmacy, and public health. The organization's capstone event, the Interprofessional Case Competition, challenges interprofessional teams of students to compete in conducting and presenting a root cause analysis of a fictitious sentinel event. The interprofessional organizational structure of the CLARION board models the kind of interprofessional equality needed to effectively solve problems in the health care system. The interaction among students from different health professions has led them to many new understandings about health care and the realization that many fundamental biases about other professions are firmly rooted in students before they enter the workplace. CLARION has enabled continued professional development of students, faculty, and practitioners, leading individual students to enhanced understanding of the health care system. It is a grassroots catalyst that has prompted faculty to reexamine traditional health professions curricula and look for ways to integrate more interprofessional opportunities into it.     

A validation study of two brief measures of depression in the cardiac population: the DMI-10 and DMI-18

The authors report on the psychometric characteristics and clinical efficacy of two versions of a recently developed screening measure of depression (the DMI-18 and DMI-10) in the cardiac population. Patients with acute coronary syndrome or heart failure (N = 322) completed the DMI measures, psychosocial questionnaires, and a semistructured clinical interview during the hospital stay. The DMI-18 and DMI-10 measures have adequate psychometric properties, demonstrating high sensitivity and specificity when evaluated against clinical judgment based on a semistructured interview. The DMI-18 and DMI-10 are appropriate for use as screening instruments in cardiac patients.     

Different composition of intrahepatic lymphocytes in the immune-tolerance and immune-clearance phase of chronic hepatitis B

Based on virological and biochemical parameters patients with chronic hepatitis B virus (HBV) are divided into distinct clinical phases: the immune-tolerance phase, the immune-clearance phase, and the inactive carrier state. Unclear is whether these phases have characteristic intrahepatic immune responses. The composition of liver-derived lymphocytes in patients with chronic HBV infection was studied. In 47 patients the composition of liver-derived lymphocytes was analyzed by flow cytometry of fine needle aspiration biopsies of the liver. The proportion natural killer (NK) cells in the liver was significantly higher in immune-tolerant than in immune-clearance patients and inactive carriers. No differences were found in proportion CD4+ T-cells and CD8+ T-cells, in these phases. However, when patients in the immune-clearance phase, with similar alanine transaminase (ALT), were grouped according to viral load, the proportion CD8+ T-cells was higher in those with high viral load. In contrast, the proportion CD4+ T-cells was increased in patients with low HBV-DNA. These differences were absent in the peripheral blood (PB). Intrahepatic HBV-specific CD8+ T-cells were mainly found in immune-clearance patients with low viral load. In conclusion, clear differences in the intrahepatic cellular infiltrate were found between the various clinical phases of chronic HBV infection. These findings are relevant to the design of new, individualized anti-viral strategies.