Inhibition of receptor-coupled adenylate cyclase by hormones is proposed to be associated with GTP hydrolysis. Since adenosine inhibits cerebral-cortical adenylate cyclase via A1 adenosine receptors, the present study attempts to verify this mechanism for A1-selective adenosine derivatives. In guinea-pig cortical membranes N6-(phenylisopropyl)adenosine (PIA) increased the Vmax. of the low-Km GT...

Through immunocytochemistry with the use of antibodies against A1 adenosine receptors (A1Rs) and confocal microscopy, we show that stimulation of A1Rs by the agonist (R)-phenylisopropyladenosine [(R)-PIA] caused a rapid (5-15 min) aggregation (clustering) of receptor molecules on the surface of DDT1MF-2 cells. Internalization of the chronically stimulated receptor was slower and occurred concom...

We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded doses of the R-isomer of phenylisopropyladenosine (R-PIA; 1 nM, 10 nM, 100 nM, 1 microM and 10 mi...

A photo-induced anisotropy (PIA) of Methyl Red (MR) azo dye embedded in PMMA polymer solid films was investigated by studying dichroic spectra and birefringence. The reversible PIA MR measured situ during photoactive irradiation process. Photoinduced order increases with the rise exposure power. It is shown that dark relaxation slows down at higher energy. rotational diffusion evaluated differe...

A single intradermal injection of the mineral oil pristane in susceptible DA.1F rats induces erosive arthritis closely mimicking rheumatoid arthritis (RA). Pristane-induced arthritis (PIA) is driven by autoreactive T cells but no autoantigen has been identified to date. We therefore analyzed B and T cell responses to autoantigens potentially involved in the pathogenesis of RA, including IgG, ci...

Cytotoxic radiotherapy unfavorably induces tumor cells to generate various proangiogenic substances, promoting post-irradiation angiogenesis (PIA), which is one of major causes of radiotherapy failure. Though several studies have reported some mechanisms behind PIA, they have not yet described the beginning proangiogenic motivator buried in the irradiated microenvironment. In this work, we reve...

BACKGROUND Glutathione S-transferases (GSTs), inducible enzymes that catalyze the detoxification of reactive electrophiles and oxidants, protect against neoplastic transformation. Prostatic adenocarcinoma and high-grade prostatic intraepithelial neoplasia (HGPIN) fail to express GSTP1, a major class of GST. This failure of expression is associated with methlyation of the GSTP1 promoter, a somat...

BACKGROUND Preinfarction angina (PIA) may be a marker of ischemic preconditioning. A decrease in infarct size, ventricular remodeling, congestive heart failure, cardiogenic shock or death was demonstrated in the presence of preinfarction angina. These findings were more evident in adults, but not in the elderly. OBJECTIVE To assess the relationship between PIA and the clinical course of elder...

The effect of mannitol upon glomerular ultrafiltration was examined in hydropenic Munich-Wistar rats. Superficial nephron filtration rate (sngfr) rose from 32.0+/-0.9 nl/min/g kidney wt to 42.0+/-1.6 (P < 0.001) in eight rats. Hydrostatic pressure gradients acting across the glomerular capillary (DeltaP) were measured in glomerular capillaries and Bowman's space with a servo-nulling device, sys...

The production of biofilm is thought to be crucial in the pathogenesis of prosthetic-device infections caused by Staphylococcus epidermidis. An experimental animal model was used to assess the importance of biofilm production, which is mediated by polysaccharide intercellular adhesin/hemagglutinin (PIA/HA), in the pathogenesis of a biomaterial-based infection. Mice were inoculated along the len...