Changes in intrathoracic impedance from a pneumothorax: insights from an implanted monitoring system

The measurement of transthoracic impedance is now possible using new implantable cardioverter-defibrillators. This can be used to monitor fall in impedance associated with increasing pulmonary oedema. We describe a case of a large rapid increase of impedance and dyspnoea related to a pneumothorax.     

Male circumcision and the risk of HIV infection

Epidemiologic data have suggested that male circumcision is a major protective factor against male heterosexual HIV transmission and may explain the significant geographic differences in the prevalence of HIV observed within sub-Saharan Africa. To assess the evidence of the protective effect of male circumcision, African studies on its association with HIV infection were reviewed. These studies' systematic lack of control of important confounding factors makes the assessment of the association between male circumcision and HIV transmission very difficult and raises doubt about the validity of the current findings. Randomized trials are needed to determine the true strength of the association. Until then, a decision to recommend mass male circumcision to prevent HIV transmission in sub-Saharan Africa is premature and risky.     

Changing investment in activities and interests in elders' lives: theory and measurement

Socioemotional selectivity and gerotranscendence, newer theories with roots in the disengagement theory of aging, provided the theoretical framework for a new measure of perceived change in investment in a variety of pursuits. The 30-item Change in Activity and Interest Index (CAII) was given to a sample of 327 outpatients aged 65-94. Items with at least 30% decreased investment responses included Entertaining in my home, Concern with others' opinions, Shopping and buying things, and Attending social events with new people. Principal Components Analysis of the index with dichotomous recoding (less vs. more or same investment) resulted in four factors: Active Instrumental (AI), Social Intellectual (SI), Spiritual Concerns (SC), and Transcendence (TR). Support for socioemotional selectivity and gerotranscendence is evident in the reported increase of importance of SI pursuits, with concurrent decrease in importance of AI activities among these respondents. Zero-order correlations of component scores with study variables suggest that AI and SI are more clearly related to older age, functional impairment, and negative affect than are SC and TR. The CAII appears to tap several dimensions of change in interests; the index gives geriatric mental health practitioners and researchers a tool to measure an aspect of social development that has been neglected in gerontology.     

Children grow and horses race: is the adiposity rebound a critical period for later obesity?

Background  

The adiposity rebound is the second rise in body mass index that occurs between 3 and 7 years. An early age at adiposity rebound is known to be a risk factor for later obesity. The aim here is to clarify the connection between the age at rebound and the corresponding pattern of body mass index change, in centile terms, so as to better understand its ability to predict later fatness.     

Modulation of human GABAA and glycine receptor currents by menthol and related monoterpenoids

Effects of common monoterpenoid alcohols and ketones were investigated on recombinant human gamma-aminobutyric acid A (GABAA; alpha1beta2gamma2s) and glycine (alpha1 homomers) receptors expressed in Xenopus oocytes. GABA currents were enhanced by coapplications of 10-300 microM: (+)-menthol>(-)-menthol>(-)-borneol>(-)-menthone=camphor enantiomers>carvone enantiomers, with menthol acting stereoselectively. By contrast, thujone diastereomers inhibited GABAA receptor currents while glycine currents were only markedly potentiated by menthol. Positive modulation by (+)-menthol was explored given its pronounced effects (e.g., at 100 microM, GABA and glycine EC20 responses increased by 496+/-113% and 135+/-56%, respectively). (+)-Menthol, 100 microM, reduced EC50 values for GABA and glycine from 82.8+/-9.9 to 25.0+/-1.8 microM, and from 98.7+/-8.6 to 75.7+/-9.4 microM respectively, with negligible effects on maximal currents. This study reveals a novel neuroactive role for menthol as a stereoselective modulator of inhibitory ligand-gated channels.     

Navy Asbestos Medical Surveillance Program (1991-1999): linear regression analysis for the effect of asbestos exposure on pulmonary function testing

The effect of asbestos exposure on pulmonary function was studied using data from the Navy Asbestos Medical Surveillance Program. Records were selected for Caucasian men from 1991 to 1999 (N = 89,318) and were analyzed using a cross-sectional, linear regression model. Dependent variables were forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), with independent continuous variables of age, height, weight, smoking, and asbestos history. Overall, the continuous variable for asbestos exposure demonstrated significant protection of +1.1 cm3/year (t = 3.278, p = 0.001) for FEV1 and +1.6 cm3/year (t = 4.225, p = 0.000) for FVC. There was significant interaction between asbestos exposure and smoking history (FEV1, -0.09 cm3/year2, t = -6.467, p = 0.000; FVC, -0.097 cm3/year2, t = -5.663, p = 0.000). This study suggests that workers within the program demonstrated minimal additional pulmonary function changes during the period, particularly if they do not smoke tobacco. The study also supports continuing smoking cessation efforts for all asbestos-exposed workers.