Unique Flexibility in Energy Metabolism Allows Mycobacteria to Combat Starvation and Hypoxia

Mycobacteria are a group of obligate aerobes that require oxygen for growth, but paradoxically have the ability to survive and metabolize under hypoxia. The mechanisms responsible for this metabolic plasticity are unknown. Here, we report on the adaptation of Mycobacterium smegmatis to slow growth rate and hypoxia using carbon-limited continuous culture. When M. smegmatis is switched from a 4.6 h to a 69 h doubling time at a constant oxygen saturation of 50%, the cells respond through the down regulation of respiratory chain components and the F1Fo-ATP synthase, consistent with the cells lower demand for energy at a reduced growth rate. This was paralleled by an up regulation of molecular machinery that allowed more efficient energy generation (i.e. Complex I) and the use of alternative electron donors (e.g. hydrogenases and primary dehydrogenases) to maintain the flow of reducing equivalents to the electron transport chain during conditions of severe energy limitation. A hydrogenase mutant showed a 40% reduction in growth yield highlighting the importance of this enzyme in adaptation to low energy supply. Slow growing cells at 50% oxygen saturation subjected to hypoxia (0.6% oxygen saturation) responded by switching on oxygen scavenging cytochrome bd, proton-translocating cytochrome bc1-aa3 supercomplex, another putative hydrogenase, and by substituting NAD+-dependent enzymes with ferredoxin-dependent enzymes thus highlighting a new pattern of mycobacterial adaptation to hypoxia. The expression of ferredoxins and a hydrogenase provides a potential conduit for disposing of and transferring electrons in the absence of exogenous electron acceptors. The use of ferredoxin-dependent enzymes would allow the cell to maintain a high carbon flux through its central carbon metabolism independent of the NAD+/NADH ratio. These data demonstrate the remarkable metabolic plasticity of the mycobacterial cell and provide a new framework for understanding their ability to survive under low energy conditions and hypoxia

Utilisation of complementary and alternative medicine (CAM) practitioners within maternity care provision: results from a nationally representative cohort study of 1,835 pregnant women

Background: There is little known about women's concurrent use of conventional and complementary health care during pregnancy, particularly consultation patterns with complementary and alternative medicine (CAM). This study examines health service utilisation among pregnant women including consultations with obstetricians, midwives, general practitioners (GPs) and CAM practitioners.Methods: A sub-study of pregnant women (n=2445) was undertaken from the nationally-representative Australian Longitudinal Study on Women's Health (ALSWH). Women's consultations with conventional practitioners (obstetricians, GPs and midwives) and CAM practitioners for pregnancy-related health conditions were analysed. The analysis included Pearson chi-square tests to compare categorical variables.Results: The survey was completed by 1835 women (response rate = 79.2%). A substantial number (49.4%) of respondents consulted with a CAM practitioner for pregnancy-related health conditions. Many participants consulted only with a CAM practitioner for assistance with certain conditions such as neck pain (74.6%) and sciatica (40.4%). Meanwhile, women consulted both CAM practitioners and conventional maternity health professionals (obstetricians, midwives and GPs) for back pain (61.8%) and gestational diabetes (22.2%). Women visiting a general practitioner (GP) 3-4 times for pregnancy care were more likely to consult with acupuncturists compared with those consulting a GP less often (p

Results in the treatment of paralytic calcaneus-valgus feet with the Westin technique

Between 1988 and 2003, 23 patients with paralytic calcaneus-valgus feet were submitted to the Westin procedure and 17 patients (25 feet) were re-evaluated. Nine patients were male and eight were female. The mean age at the surgical procedure was 8±5 years. The aetiology of paralysis was sequelae of poliomyelitis in 6 patients (8 feet) and of myelomeningocele in 11 patients (17 feet). The mean follow-up period was 6±6 years. The results were analysed clinically and radiographically considering the decrease of the retropulsion, the patient’s satisfaction, and the increase of the lateral tibiocalcaneal angle. Results were considered satisfactory when the patients showed a decrease of the retropulsion during gait, improvement of the gait pattern, and an increase of the tibiocalcaneal angle. As an overall result, 16 patients (94.2%) were satisfied and 1 patient (two feet) dissatisfied with the outcome. The increase of the tibiocalcaneal angle was significant for the myelomeningocele patients (P=0.001), but not for poliomyelitis (P=0.053). No statistical relation between the follow-up period and the increase of the tibiocalcaneal angle was found (r=0.04). The authors concluded that the Westin procedure is a good technique for the treatment of paralytic calcaneus valgus feet with myelomeningocele

Meditation and psychological health: modeling theoretically derived predictors, processes, and outcomes

Despite evidence attesting to positive psychological effects of meditation, little is known about how variance in the level of engagement with meditation actually relates to positive outcomes. This study draws on multiple traditional and contemporary theoretical frameworks to (1) uncover fundamental aspects of variability in meditation practice, (2) test the role of several primary and secondary processes believed to be responsible for positive effects, and (3) explore a range of positive and negative outcomes believed to be closely aligned with the original intended out-comes of meditation practices. Using two large (each N>500) heterogeneous samples of meditation practitioners, this study calibrated and then cross-validated a theoretical model testing the plausibility of several causal pathways linking variation in experience with meditation to positive and negative psychological outcomes. Results showed that individual differences in meditation involve both behavioral aspects accounting for the degree of engagement, and psychological aspects incorporating the intensity or depth of this engagement. Variation in these aspects accounts for large proportions of variance in psychological health and functioning outcomes. Several factors representing attention refinement (mindfulness), changes in self-perception and outlook (transcendence), worldview (insight), and psychological development serve as plausible change mechanisms serving to transmit the effects of meditation on psychological health and functioning