			Home About us Contact

This Decrease (this + decrease)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

A glia,neuron alanine/ammonium shuttle is central to energy metabolism in bee retina

THE JOURNAL OF PHYSIOLOGY, Issue 8 2008
Jonathan A. Coles
It has been proposed that glial cells may supply carbon fuel to neurons and also that there are fluxes of ammonium from neurons to glia. We have investigated both these proposals in Apis retinal slices, in which virtually all the mitochondria are in the photoreceptor neurons. Normally the superfusate contained no substrate of energy metabolism; addition of glucose or alanine did not increase oxygen consumption , confirming that the neurons received adequate substrate from glycogen in the glia. 1,4-Dideoxy-1,4-imino- d -arabinitol (DAB, 100 ,m), an inhibitor of glycogen phosphorylase, progressively decreased . This decrease was reversed by alanine but not glucose. Ammonium-sensitive microelectrodes did not detect significant extracellular [NH4+] ([NH4+]e) in slices superfused with normal superfusate. Removal of Cl,, necessary for cotransport of NH4+ into the glia, increased [NH4+]e so that at the end of 2 min photostimulation mean [NH4+]e was 0.442 mm (s.e.m.= 0.082 mm, n= 16). In 0 Cl,, [NH4+]e was reduced by 2-(methylamino)isobutyrate (MeAIB) an inhibitor of alanine transport. MeAIB also blocked oxidation of alanine in the presence of DAB, but did not decrease in normal superfusate. Lactate (l and d) and pyruvate (but not glucose) increased in DAB and decreased [NH4+]e in 0 Cl,. These results strengthen the evidence that in superfused retinal slices, glucose is metabolized exclusively in the glia, which supply alanine to the neurons, and that ammonium returns to the glia. They also show that another fuel (perhaps lactate) can be supplied by the glia to the neurons. [source]

Apoptotic activity of doxazosin on prostate stroma in vitro is mediated through an autocrine expression of TGF-,1

THE PROSTATE, Issue 3 2001
Kenneth Y. Ilio
Abstract Background Doxazosin, an alpha-adrenergic antagonist, has been shown to induce apoptosis in prostatic stromal cells. The mechanism of this apoptotic action by Doxazosin remains undefined. The present study was carried out to demonstrate that the effect of Doxazosin on apoptosis of prostate stromal cells is mediated through an autocrine action of TGF-,1. Methods Primary cultures of human prostate cells were treated with varying concentrations of Doxazosin (0, 0.1, 1, 10, and 100 ,M) for a period up to 3 days. At the end of the 3-day culture, cell numbers were counted. Apoptosis was assessed by a colorimetric terminal deoxyribonucleotide transferase labeling technique. TGF-,1 was determined by enzyme-linked immunosorbent assay (ELISA). Results Compared to control cultures, cell numbers were significantly decreased as much as 68.4% in cultures treated with 10 ,M of Doxazosin after 3 days incubation, while apoptosis increased by 64.7% in cultures treated with the same concentration of Doxazosin after 24 h. This decrease in cell number was reversed when antibody to TGF-,1 was added to these cultures. Addition of TGF-,1 (0, 1.0, and 10 ng/mL) to the cultures also decreased the cell numbers. Quantitation of TGF-,1 in lysates of cells by ELISA revealed that the cells treated with Doxazosin (10 ,M) produced as much as 62.5% more TGF-,1 than in that of untreated cells. Conclusions These results demonstrate that the apoptotic effect of Doxazosin on human prostatic stromal cells is mediated through an autocrine production of TGF-,1. Prostate 48:131,135, 2001. © 2001 Wiley-Liss, Inc. [source]

Influence of autogenous leucocytes and Escherichia coli on sperm motility parameters in vitro

ANDROLOGIA, Issue 2 2003
T. Diemer
Summary. Urogenital infections are considered important factors in male infertility. In this in vitro study we have evaluated the impact of leucocytes in association with an artificial infection with Escherichia coli on the motility of human spermatozoa. Ejaculates and blood samples were obtained from healthy donors with normal semen parameters. Ejaculates were prepared by swim-up technique and five fractions were isolated for incubation. Leucocyte subtypes were separated from blood samples by gradient centrifugation. Purified sperm suspensions were adjusted to a concentration of 20 × 106 ml,1 and incubated with lymphocytes/ monocytes, polymorphonuclear granulocytes (PMN), and E. coli. Samples were incubated for up to 6 h at 37 °C. Motility analysis was performed using a computer-assisted sperm analyzer (CASA). Spermatozoa incubated with 3 × 106 PMN ml,1 revealed a significant (P=0.003) decrease in progressive motility after 2 h. This decrease remained weakly significant (P=0.024) after 4 and 6 h. Lymphocytes and monocytes had no effect on sperm motility. Spermatozoa incubated with granulocytes and E. coli demonstrated highly significant alterations in motility after 4 and 6 h of incubation (P < 0.001). The PMN indicate an effect on motility of spermatozoa under experimental conditions. However, the results suggest that bacteria are the primary agents that interfere with sperm motility. [source]

Cardiovascular changes induced by cold water immersion during hyperbaric hyperoxic exposure

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2007
Alain Boussuges
Summary The present study was designed to assess the cardiac changes induced by cold water immersion compared with dry conditions during a prolonged hyperbaric and hyperoxic exposure (ambient pressure between 1·6 and 3 ATA and PiO2 between 1·2 and 2·8 ATA). Ten healthy volunteers were studied during a 6 h compression in a hyperbaric chamber with immersion up to the neck in cold water while wearing wet suits. Results were compared with measurements obtained in dry conditions. Echocardiography and Doppler examinations were performed after 15 min and 5 h. Stroke volume, left atrial and left ventricular (LV) diameters remained unchanged during immersion, whereas they significantly fell during the dry session. As an index of LV contractility, percentage fractional shortening remained unchanged, in contrast to a decrease during dry experiment. Heart rate (HR) significantly decreased after 5 h, although it had not changed during the dry session. The changes in the total arterial compliance were similar during the immersed and dry sessions, with a significant decrease after 5 h. In immersed and dry conditions, cardiac output was unchanged after 15 min but decreased by almost 20% after 5 h. This decrease was related to a decrease in HR during immersion and to a decrease in stroke volume in dry conditions. The hydrostatic pressure exerted by water immersion on the systemic vessels could explain these differences. Indeed, the redistribution of blood volume towards the compliant thoracic bed may conceal a part of hypovolaemia that developed in the course of the session. [source]