Serum ALT levels. Effect of sex, race, and obesity on unit rejection rate.

Alanine aminotransferase (ALT) measurements in blood donors has been advocated as a surrogate test for non-A, non-B hepatitis. Use of the recommended single cutoff value for all donors resulted in disqualifying four times as many males as females in a group of 4712 donors. Separate cutoff values were calculated for male and female donors.

Specific [3H]SCH23390 binding to dopamine D1 receptors in cerebral cortex and neostriatum: evidence for heterogeneities in affinity states and cortical distribution.

The tritiated antagonist SCH23390 was used to identify dopamine D1 receptors in the cerebral cortex and neostriatum. The kinetic properties of binding were investigated in parallel experiments with membrane preparations from both tissues. The densities of receptors (Bmax) and the dissociation constants (KD) were determined from saturation curves, and the specificity of binding verified in competition experiments using agonists and antagonists.

Distribution of dopamine D1 receptors in rat cortical areas, neostriatum, olfactory bulb and hippocampus in relation to endogenous dopamine contents.

The tritiated dopamine D1 antagonist SCH23390 was employed to determine the densities of D1 receptors in seven discrete and functionally identified cortical areas (cingulate, frontal, parietal, primary somatosensory, primary visual, retrosplenial and entorhinal-piriform) as well as in the neostriatum, hippocampus and olfactory bulbs. In addition, the tissue levels of the catecholamines NA, AD, DA, the indoleamine 5-HT and their main metabolites (MHPG, DOPAC, HVA, 3-MT, 5-HTP and 5-HIAA) were measured in the different regions by HPLC with electrochemical detection. The Scatchard analysis of saturation curves revealed the highest density of [3H]SCH23390 binding sites for the neostriatum, while the densities were 10-20 times lower for total cerebral cortex and hippocampus respectively.

Stereospecific binding of a new benzazepine, [3H]SCH23390, in cortex and neostriatum.

The binding of the D1 antagonist SCH23390 to membrane preparations from rat cerebral cortex was examined using enantiomers of dopamine agonists and antagonists to compete with the bound [3H]SCH23390 at its Kd value. The competition curves were compared with those obtained with preparations from the neostriatum. The results demonstrate that specific [3H]SCH23390 binding in the cerebral cortex has the same pharmacological profile as in the neostriatum, so that this radioligand can be used to label dopamine D1 receptors in brain regions with a sparse dopaminergic innervation.

Adrenergic receptor and catecholamine distribution in rat cerebral cortex: binding studies with [3H]prazosin, [3H]idazoxan and [3H]dihydroalprenolol.

The tritiated adrenergic antagonists [3H]dihydroalprenolol ([3H]DHA; beta-receptors), [3H]prazosin ([3H]PRZ; alpha 1-receptors), and [3H]idazoxan ([3H]IDA; alpha 2-receptors) were used to determine the distribution of these sites in 5 defined areas of the adult rat cerebral cortex. The highest density of [3H]PRZ binding was found in the prefrontal cortex, with a lower and homogeneous distribution for the frontal, parietal, occipital and temporal areas. The [3H]IDA binding sites were fairly uniform for all areas, except for the temporal cortex where it was very dense.

Alpha-1 and alpha-2 adrenoceptor binding in cerebral cortex: competition studies with [3H]prazosin and [3H]idazoxan.

The tritiated adrenergic antagonists prazosin ([3H]PRZ) and idazoxan ([3H]IDA, or RX-781094) bind specifically and with high affinity in membrane preparations from cerebral cortex to alpha-1- and alpha-2-adrenoceptors respectively. Saturation experiments, performed to determine the density of receptors (Bmax; maximum binding capacity) and the dissociation constant (Kd 25 degrees C), were analyzed by the methods of Eadie and Hofstee, iterative modelling, and the procedure of Hill. The pharmacologic properties and specificity of the labelling was verified by displacement experiments using alpha-adrenergic antagonists and agonists.

Effects of p-chlorophenylalanine on cortical monoamines and on the activity of noradrenergic neurons.

The catecholamines noradrenaline, dopamine, adrenaline, the indoleamine 5-hydroxy-tryptamine (5-HT; serotonin), and some of their major metabolites were assayed, using high performance liquid chromatography (HPLC), in the neocortex of normal rats as well as in animals in which 5-HT synthesis had been inhibited with p-chlorophenylalanine. Besides important depletions in serotonin and in 5-hydroxyindole-3-acetic acid, noradrenaline levels were significantly reduced, but the content in 3-methoxy-4-hydroxyphenylglycol was increased, indicating an augmented utilization of this amine. The levels of dopamine and 3-methoxytyramine were also reduced, although homovanillic acid and 3,4-dihydroxyphenylacetic acid levels remained constant.

Alpha-1 adrenoceptors are decreased in human epileptic foci.

Cortical alpha-1 adrenoceptors were measured in tissues obtained from 10 patients immediately following temporal lobectomy for intractable partial epilepsy. At operation each patient exhibited spontaneous spiking restricted to either the anterior (n = 5) or posterior (n = 5) portion of the first two temporal gyri. Control samples were obtained from the nonspiking half of the same gyrus.