DeFries–Fulker and Pearson–Aitken Model-fitting Analyses of Reading Performance Data from Selected and Unselected Twin Pairs

Although a comparison of concordance rates for deviant scores in identical and fraternal twin pairs can provide prima facie evidence for a genetic etiology, information is not fully utilized when continuous measures are analyzed in a dichotomous manner. Thus, DeFries and Fulker (Behav Genet 15:467–473, 1985; Acta Genet Med Gemellol, 37:205–216, 1988) developed a regression-based methodology (DF analysis) to assess genetic etiology in both selected and unselected twin samples. While the DF analysis is a very versatile and relatively powerful statistical approach, it is not easily extended to the multivariate case. In contrast, structural equation models may be readily extended to analyze multivariate data sets (Neale and Cardon, Methodology for genetic studies of twins and families, 1992). However, such methodologies may yield biased estimates of additive genetic, shared environmental, and non-shared environmental influences when multivariate models are fitted to selected twin data. Therefore, the Pearson–Aitken (PA) selection formula (Aitken, Proc Edinburgh Math Soc B, 4:106–110, 1934) was used to analyze reading performance data from twins with reading difficulties (selected sample) and a population of normally-achieving twin pairs (control sample). As a comparison, DF models were also fitted to these same data sets. In general, resulting estimates of additive genetic, shared environmental, and non-shared environmental influences were similar when the DF and PA models were fitted to the data. However, the PA selection formula may be more readily generalized to the multivariate case. Edited by Hermine Maes.     

Genetic Covariation Between the Author Recognition Test and Reading and Verbal Abilities: What Can We Learn from the Analysis of High Performance?

The Author Recognition Test (ART) measures print exposure and is a unique predictor of phonological and orthographic processes in reading. In a sample of adolescent and young adult twins and siblings (216 MZ/430 DZ pairs, 307 singletons; aged 11–29 years) ART scores were moderately heritable (67%) and correlated with reading and verbal abilities, with genes largely accounting for the covariance. We also examine whether high (and low) (i.e. 1SD above the mean) represents a quantitative extreme of the normal distribution. Heritability for high ART was of similar magnitude to the full sample, but, a specific genetic factor, independent from both low ART performance and high reading ability, accounted for 53–58% of the variance. This suggests a distinct genetic etiology for high ART ability and we speculate that the specific genetic influence is on orthographical processing, a critical factor in developing word recognition skills. Edited by Robert Plomin.     

Can human cardiovascular regulation during exercise be learnt from feedback from arterial baroreceptors?

During dynamic exercise, a large fall in systemic vascular resistance occurs. Arterial pressure (AP) is, however, maintained through a combination of central command and neural activity from muscle afferents that adjust the autonomic outflow to the circulation. How these signals are calibrated to provide accurate regulation of AP remains unclear. This study tests the hypothesis that the calibration can be 'learnt' through feedback from the arterial baroreceptors arising over multiple trials of exercise. Eight healthy subjects undertook three different protocols in random order. The test protocol consisted of 7 days' training, when subjects were exposed on 70 occasions to 4 min of exercise (50% of maximal oxygen uptake capacity) paired with neck suction (-40 mmHg) to mimic an excessive rise in AP at the carotid baroreceptors with exercise. Two control protocols involved training with either exercise or neck suction alone. No significant changes in mean AP, diastolic AP or heart rate during normal exercise were detected following training with any protocol. However, the rise in systolic AP with exercise was attenuated by an average of 7.3 +/- 2.0 mmHg (mean +/- s.e.m., P < 0.01) on the first and second days following training with the test protocol, but not with either control protocol (P < 0.05 for difference between protocols, ANOVA). In conclusion, this study failed to show that mean AP during normal exercise could be reduced through prior conditioning by overstimulation of the baroreceptors during exercise. However, a reduction in systolic AP was observed that suggests the presence of some plasticity within the autonomic response, consistent with our hypothesis.     

Does disclosure of emotions facilitate recovery from bereavement? Evidence from two prospective studies

Two longitudinal studies assessed whether disclosure of emotions facilitates recovery from bereavement. Study 1 tested prospectively over a 2-year period whether the extent to which bereaved persons talked about their loss to others and disclosed their emotions was associated with better adjustment to the loss of a marital partner. There was no evidence that disclosure facilitated adjustment. Study 2 randomly assigned recently bereaved individuals either to the Pennebaker writing task (J. W. Pennebaker & S. K. Beall, 1986) or to no-essay control conditions. The writing task did not result in a reduction of distress or of doctors visits either immediately after the bereavement or at a 6-month follow-up. Beneficial effects were not demonstrated for bereaved persons who had suffered an unexpected loss or who at the time of the study still expressed a high need for emotional disclosure.     

Does name-based HIV reporting deter high-risk persons from HIV testing? Results from San Francisco

OBJECTIVE: Name-based HIV reporting has been recommended as a method to track the HIV epidemic but may deter or delay at-risk persons from HIV testing. Previous studies of a deterrent effect of HIV reporting were not conducted in areas with high HIV infection rates and politically active populations. METHODS: In a cross-sectional survey, men who have sex with men (MSM) recruited from gay bars, heterosexuals recruited from the sexually transmitted disease clinic, and injection drug users (IDUs) recruited from street venues were administered a face-to-face anonymous questionnaire. RESULTS: Ninety-four percent of the 118 MSM, 76% of the 99 heterosexuals, and 97% of 105 IDUs surveyed were tested. Six percent of MSM, 9% of heterosexuals, and none of the IDUs correctly identified California's HIV reporting regulations. Of the 75 (25%) participants who thought California had a name-based HIV reporting system, 2 were never tested and 23 had not been tested in the past 12 months. None of those who had never been tested and 2 of those who had not been tested in the past 12 months cited fear of being reported as a reason for not testing recently. CONCLUSION: Fear of reporting is an infrequently cited reason for deterring or delaying testing.     

Co-inhibitors：from basic to clinic

Efficient activation of T lymphocytes through Tcell receptor (TCR) depends on two signals. Thefirst signal (signal one) is derived from TCR in teracting with the MHC/antigenic peptide com plex, which confers antigenic specificity to theimmune response. The second signal (signal two)is provided by the engagement of T cell surface re ceptors with their specific ligands on antigen pre senting cell (APC) [1]. As there is growing evi dence for bidirectional communications an…     

Are infections protecting from atopy?

The 'Hygiene Hypothesis' proposes that overcrowding and unhygienic contacts early in life may protect from atopic diseases by facilitating exposure to microbes. Longitudinal studies have recently shown that among subjects exposed early in life to other children at home, or at day care, the risk of wheezing steadily declined with age to levels significantly lower than controls. Evidences supporting a protective role of respiratory infections or BCG immunization on the development of allergic asthma are still insufficient. By contrast, the observation of a lower prevalence of atopic sensitization among children raised on a farm has been consistently reproduced. Several new studies have recently investigated the role of changes of human microbial flora, declining exposure to foodborne and orofecal infections, to helminths and to environmental sources of endotoxin as putative contributors to the rise of allergy and asthma cases among populations living with a western lifestyle.     

Do proficiency testing participants learn from their mistakes? Experience from the EXCEL throat culture module

CONTEXT: Participation in proficiency testing is required under the Clinical Laboratory Improvement Amendments of 1988. Although the primary purpose of this testing is evaluation of current laboratory performance, a major secondary benefit of such testing is postulated to be progressive improvement in laboratory performance over time as laboratories learn from their previous experiences and feedback. OBJECTIVE: To test the hypothesis that a secondary result of proficiency testing is improvement over time of laboratory performance. DESIGN: The performance of participants in a large proficiency testing program (EXCEL), designed for clinic and office laboratories, on a specific problematic competence, the ability to differentiate group A streptococcus from group C streptococci, was monitored during a 6-year period (1996-2001) for changes in participant performance. INTERVENTIONS: With each testing cycle, feedback on performance relative to peers and an educational discussion analyzing performance and suggesting best practices was submitted to participants. RESULTS: Despite consistent feedback, there was no significant change in participant performance throughout the period studied. CONCLUSIONS: In a large, stable proficiency testing program, a significant throat culture competence, which demonstrated less than optimal performance, did not improve over time, suggesting that current utilization of proficiency testing results in laboratory improvement programs is suboptimal.     

Ancient parasites from endemic deer from “CUEVA PARQUE DIANA” archeological site,Patagonia, Argentina

Parasitology Research - The narrow Andean-Patagonian temperate rainforest strip in the west of southern South America is inhabited by two endemic species of cervids, the southern pudu (Pudu puda)...     

Nanosilica—from medicine to pest control

Nanotechnology is a broad interdisciplinary area of research, development, and industrial activity that has been growing rapidly worldwide for the past decade. More ambitious uses of nanoparticles are bioremediation of contaminated environments, controlled release of fragrances, biocides, and antifungals on textiles. Silica nanocomposites have received much attention because of its thermal degradation behavior and applications in chromatography, medicine, optics, etc. Nanobiotech takes agriculture from the battleground of genetically modified organisms to the brave new world of atomically modified organisms where rice has been modified atomically. Silica has been widely applied in various industries. Application of gold-coated silica has been used in the treatment for benign and malignant tumor. Surface-modified hydrophobic as well as lipophilic nanosilica could be effectively used as novel drugs for treatment of chicken malaria and nuclear polyhedrosis virus (BmNPV), a scourge in silkworm industry. Here, the authors attempt to provide a review to explain the impact of nanosilica on basic biology, medicine, agro-nanoproducts, and use of amorphous nanosilica as biopesticide.     

Characterization of VP6 genes from rotavirus strains collected in the United States from 1996–2002

We sequenced 22 VP6 genes from common rotavirus strains P[8], G1; P[4], G2; P[8], G3; P[8], G4 and P[8], G9 and uncommon type P[6], G9 collected in the US over a 6-year period. All strains defined as members of VP6 antigenic subgroup (SG) I according to reactivity patterns with monoclonal antibodies formed a genetic cluster (Genogroup I) with SG I reference strains. Similarly, all strains in antigenic SGII formed a group (Genogroup II) with corresponding standard strains of the same SG. Most US strains of each genogroup had diverged by 10–15% from the VP6 gene sequence of reference strains collected >20 years earlier and some recent isolates from other countries. Evolutionary analysis demonstrated that recently isolated US strains of both genogroups have diverged into 2–3 related clusters consistent with other recent findings. Unexpectedly, some recent isolates from other countries have diverged greatly from both older reference isolates and from the recent US isolates characterized here. This finding suggests that genetic diversity in human rotavirus VP6 genes may be greater than previously recognized. These sequences will help in the construction of a VP6 gene database to aid in the development of broadly reactive molecular assays and permit identification of regions where primers and probes for existing assays may need to be redesigned. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of CDC.     

HIV Production from Purified Monocytes Isolated from Antiretroviral-NaÏve and Protease Inhibitor-Treated HIV-1--Infected Patients

Abstract

Purpose: We obtained peripheral blood monocytes from HIV-1-infected patients and differentiated them into macrophages in vitro to investigate the contribution of purified monocytes to plasma viremia in HIV-infected patients. Method: We compared the production of HIV-1 from purified monocytes isolated from patients who were receiving antiviral therapy to those who were not. We obtained monocytes from 29 antiretroviral-nai¨ve (ARVN) patients and 35 protease inhibitor (PI)-treated HIV-infected patients (20 with undetectable plasma HIV). Cells were cultured with phorbol myristate acetate to induce HIV replication. Results: HIV p24 core antigen was present in supernatants of 9/29 (31%) of ARVN patients (mean = 102 pg/mL). In contrast to ARVN patients, p24 was not found in supernatants of any PI-treated patient (p = .01). Thus, purified monocytes from some ARVN patients produce HIV, but we were unable to detect HIV production from monocytes from PI-treated patients, regardless of their virologic response. Conclusion: Monocytes may contribute to plasma viremia in ARVN patients but may not do so in PI-treated patients.