Polarized distribution of HCO3- transport in human normal and cystic fibrosis nasal epithelia

The polarized distribution of HCO3− transport was investigated in human nasal epithelial cells from normal and cystic fibrosis (CF) tissues. To test for HCO3− transport via conductive versus electroneutral Cl−/HCO3− exchange (anion exchange, AE) pathways, nasal cells were loaded with the pH probe 2′,7′-bis(carboxyethyl)-5(6)-carboxyfluorescein and mounted in a bilateral perfusion chamber. In normal, but not CF, epithelia, replacing mucosal Cl− with gluconate caused intracellular pH (pHi) to increase, and the initial rates (ΔpH min−1) of this increase were modestly augmented (∼26 %) when normal cells were pretreated with forskolin (10 μm). Recovery from this alkaline shift was dependent on mucosal Cl−, was insensitive to the AE inhibitor 4,4′-diisothiocyanatodihydrostilbene-2,2′-disulfonic acid (H2DIDS; 1.5 mm), but was sensitive to the cystic fibrosis transmembrane conductance regulator (CFTR) channel inhibitor diphenylamine-2-carboxylate (DPC; 100 μm). In contrast, removal of serosal Cl− caused pHi to alkalinize in both normal and CF epithelia. Recovery from this alkaline challenge was dependent on serosal Cl− and blocked by H2DIDS. Additional studies showed that serosally applied Ba2+ (5.0 mm) in normal, but not CF, cells induced influx of HCO3− across the apical membrane that was reversibly blocked by mucosal DPC. In a final series of studies, normal and CF cells acutely alkaline loaded by replacing bilateral Krebs bicarbonate Ringer (KBR) with Hepes-buffered Ringer solution exhibited basolateral, but not apical, recovery from an alkaline challenge that was dependent on Cl−, independent of Na+ and blocked by H2DIDS. We conclude that: (1) normal, but not CF, nasal epithelia have a constitutively active DPC-sensitive HCO3− influx/efflux pathway across the apical membrane of cells, consistent with the movement of HCO3− via CFTR; and (2) both normal and CF nasal epithelia have Na+-independent, H2DIDS-sensitive AE at their basolateral domain

NIRS assessment of brain hemodynamics

Near Infrared Spectroscopy (NIRS) allows for assessing brain hemodynamics non-invasively. In NIRS studies, the maneuver of breath holding is frequently used as an activation of the brain autoregulation response. However, breath holding is not always feasible or effective in the clinical practice. We explored the possibility of using kapalabathi, an ancient yoga respiration technique, as an alternate activation maneuver. We studied the brain oxygenation response to kapalabathi, in yoga practitioners, in three different postures. In all the three postures considered Kapalabathi produces a measurable effect on the oxygen availability at the brain cortex level. Remarkable differences were observed in the brain autoregulatory response of smoker and non-smoker practitioners

A DC-DC Step-Up mu-Power Converter for Energy Harvesting Applications, Using Maximum Power PointTracking, Based on Fractional Open Circuit Voltage

A DC-DC step-up micro power converter for solar energy harvesting applications is presented. The circuit is based on a switched-capacitorvoltage tripler architecture with MOSFET capacitors, which results in an, area approximately eight times smaller than using MiM capacitors for the 0.131mu m CMOS technology. In order to compensate for the loss of efficiency, due to the larger parasitic capacitances, a charge reutilization scheme is employed. The circuit is self-clocked, using a phase controller designed specifically to work with an amorphous silicon solar cell, in order to obtain themaximum available power from the cell. This will be done by tracking its maximum power point (MPPT) using the fractional open circuit voltage method. Electrical simulations of the circuit, together with an equivalent electrical model of an amorphous silicon solar cell, show that the circuit can deliver apower of 1132 mu W to the load, corresponding to a maximum efficiency of 66.81%

Laparoscopic Gastric Sleeve and Micronutrients Supplementation: Our Experience

Background. Laparoscopic gastric sleeve (LGS) has been recently introduced as a stand-alone, restrictive bariatric surgery. Theoretically, LGS attenuates micronutrients deficiencies and associated complications that were typically observed following malabsorptive procedures. The aim of this study was to assess some micronutrients and mineral deficiencies in patients undergoing LGS. Methods. In the period between July 2008 and April 2010, 138 obese patients (110 females and 28 males) with mean BMI 44.4 kg/m2 ± 6.5, mean age 43.9 ± 10.9 years were enrolled and underwent LGS. Patients were followed up with routine laboratory tests and anthropometric measurements and assessed for nutritional status, as regards vitamin B12, folic acid, iron, hemoglobin, calcium, and vitamin D, every three months throughout 12 months. Results. 12 months after sleeve, patients did not show iron deficiency and/or anemia; plasma calcium levels were in the normal range without supplementation from the sixth month after the operation. Vitamin B12 and folic acid were adequately supplemented for all the follow-up period. Vitamin D was in suboptimal levels, despite daily multivitamin supplementation. Conclusion. In this study, we showed that LGS is an effective surgery for the management of morbid obesity. An adequate supplementation is important to avoid micronutrients deficiencies and greater weight loss does not require higher dosage of multivitamins

Neural responses to facial and vocal expressions of fear and disgust

Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus

Population coding by globally coupled phase oscillators

A system of globally coupled phase oscillators subject to an external input is considered as a simple model of neural circuits coding external stimulus. The information coding efficiency of the system in its asynchronous state is quantified using Fisher information. The effect of coupling and noise on the information coding efficiency in the stationary state is analyzed. The relaxation process of the system after the presentation of an external input is also studied. It is found that the information coding efficiency exhibits a large transient increase before the system relaxes to the final stationary state.Comment: 7 pages, 9 figures, revised version, new figures added, to appear in JPSJ Vol 75, No.