Role of the Escherichia coli FocA and FocB formate channels in controlling proton/potassium fluxes and hydrogen production during osmotic stress in energy-limited, stationary phase fermenting cells

Escherichia coli FocA and FocB formate channels export formate or import it for further disproportionation by the formate hydrogenlyase (FHL) complex to H2 and CO2. Here, we show that under pH and osmotic stress FocA and FocB play important roles in regulating proton and potassium fluxes and couple this with H2 production in stationary-phase cells. Using whole-cell assays with glucose as electron donor, a focB mutant showed a 50 % decrease in VH2, while N'N'-dicyclohexylcarbodiimide (DCCD) treatment of osmotically stressed cells underlined the role of FOF1 ATPase in H2 production. At pH 7.5 and under osmotic stress FocB contributed to the proton flux but not to the potassium flux. At pH 5.5 both formate channels contributed to the proton and potassium fluxes. Particulalry, a focA mutant had 40 % lower potassium flux whereas the proton flux increased approximately two-fold. Moreover, at pH 5.5H2 production was totally inhibited by DCCD in the focA mutant. Taken together, our results suggest that depending on external pH, the formate channels play an important role in osmoregulation by helping to balance proton/potassium fluxes and H2 production, and thus assist the proton FOF1-ATPase in maintenance of ion gradients in fermenting stationary-phase cells.

Factors associated with health-related quality of life among people with visual impairments living in nursing homes in Armenia: a cross-sectional study

PURPOSE

The study aimed to examine the effect of visual impairment (VI), eye diseases, and other risk factors on health-related quality of life (HRQoL) in nursing home residents in Armenia.

METHODS

This cross-sectional study administered an interviewer-administered structured questionnaire to collect information about socio-demographics, chronic diseases, HRQoL, smoking, receiving and giving instrumental/emotional social support, and sleeping disorders among 313 nursing home residents. An ophthalmic examination of the participants was conducted.

RESULTS

The mean age was 72.5 years, ranging from 45.5 to 91.4. Women constituted 50% of the sample. The prevalence of normal vision by presenting visual acuity with available correction was 55.3%, while VI and blindness were present in 40.8% and 3.9%, respectively. Uncorrected refractive error (URE) was found in 20% of participants. The mean HRQoL score was 51.3, ranging from 7.9 to 95.0. In the adjusted analysis, having at least one chronic non-communicable disease, sleeping disorders, eye diseases, URE, VI, blindness, and giving instrumental social support were associated with HRQoL.

CONCLUSIONS

Regular eye care services could improve the eye health and HRQoL of nursing home residents. Interventions addressing vision loss and chronic non-communicable diseases could enhance the functioning and overall well-being of the target population.

The age-dependent relationship between resting heart rate variability and functional brain connectivity

Resting heart rate variability (HRV), an index of parasympathetic cardioregulation and an individual trait marker related to mental and physical health, decreases with age. Previous studies have associated resting HRV with structural and functional properties of the brain - mainly in cortical midline and limbic structures. We hypothesized that aging affects the relationship between resting HRV and brain structure and function. In 388 healthy subjects of three age groups (140 younger: 26.0 ± 4.2 years, 119 middle-aged: 46.3 ± 6.2 years, 129 older: 66.9 ± 4.7 years), gray matter volume (GMV, voxel-based morphometry) and resting state functional connectivity (eigenvector centrality mapping and exploratory seed-based functional connectivity) were related to resting HRV, measured as the root mean square of successive differences (RMSSD). Confirming previous findings, resting HRV decreased with age. For HRV-related GMV, there were no statistically significant differences between the age groups, nor similarities across all age groups. In whole-brain functional connectivity analyses, we found an age-dependent association between resting HRV and eigenvector centrality in the bilateral ventromedial prefrontal cortex (vmPFC), driven by the younger adults. Across all age groups, HRV was positively correlated with network centrality in the bilateral posterior cingulate cortex. Seed-based functional connectivity analysis using the vmPFC cluster revealed an HRV-related cortico-cerebellar network in younger but not in middle-aged or older adults. Our results indicate that the decrease of HRV with age is accompanied by changes in functional connectivity along the cortical midline. This extends our knowledge of brain-body interactions and their changes over the lifespan.

Incidence of cleft lip and palate in Tehran

The purpose of this study was to assess the epidemiology and some of the possible risk factors causing oral cleft in Tehran. The study was a 7-year retrospective study from March 1998 to March 2005. Twenty-five live births with cleft lip and/or palate (CL+/-P) were born between 20 March 1998 and 20 March 2005 from the total of 11,651 live births in a maternity hospital in Tehran. After recognizing the child as a cleft patient, previous and following children born were recognized as a noncleft sample. Cleft and noncleft samples were compared for variables such as gender, mother's age, parity, consanguineous marriage and infant's weight, and then analyzed with Chi-square. The overall incidence was 2.14 per 1000 live births. CL+ P is more prevalent, which was 52% and the least incidence was for "only cleft lip'' patients, which was 12%. This study reveals that the incidence of oral clefts in Tehran is higher than many other countries. Consanguineous marriage and low birth weight in cleft group were significant statistically from those of noncleft group.

[Effect of hypertensive pregnancy complications on neonatal outcome of growth retarded fetuses]

OBJECTIVE

To determine the effect of hypertensive disorders in pregnancy on the neonatal outcome of growth restricted fetuses. There is conflicting data on the effect of hypertension during pregnancy on the incidence of neonatal respiratory distress syndrome (RDS) and intraventricular hemorrhage. Some studies report a lower incidence of RDS and intraventricular hemorrhage in infants of hypertensive mothers, whereas other studies report a similar or higher incidence in infants born to hypertensive mothers.

STUDY DESIGN

We performed a retrospective analysis of 220 growth restricted fetuses born between January 1, 1996 to July 1, 1997 at the Department of Obstetrics and Gynecology of the University-Hospital at Homburg/Saar. Data were obtained by review of the medical records. Growth restricted infants born to preeclamptic women or women with HELLP syndrome were compared to growth restricted fetuses born to mothers without hypertensive disorders.

RESULTS

Growth restricted fetuses born to hypertensive mothers had a significant lower birth weight (p < 0.05). The incidence of RDS in children born to hypertensive mothers was significantly higher (p < 0.05, p < 0.01) and they stayed significantly longer in the neonatal intensive care unit (p < 0.01). In contrast to infants born to mothers with HELLP syndrome (n = 7) there was no difference in the incidence of intraventricular hemorrhage, infection, sepsis, necrotizing enterocolitis or cardiac complications (arrhythmia, insufficiency) in case of preeclampsia (n = 68). The perinatal mortality of infants born to hypertensive mothers was significantly higher (p < 0.05, p < 0.01).

CONCLUSION

This study does not support the contention that hypertensive disorders in pregnancy have a beneficial effect on the postnatal course of IUGR infants.