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Lipoprotein-platelet interactions are very important in atherosclerosis and thrombosis. Several studies have been carried out on specific binding of various lipoproteins to platelets. But there is considerable disagreement about the details of these binding sites. Although low-density lipoprotein (LDL) receptors of several cells have been studied extensively, there is little datum about high-density lipoprotein (HDL) receptors. Apolipoprotein (apo) A-I may play a major role in the determination of the specificity of HDL receptors. In this study, binding of apo A-I to platelets was investigated by using a flow cytometric method. Citrated blood samples were obtained from five healthy and seven hypercholesterolemic subjects. Apo A-I antibody was incubated with the citrated whole blood before and after activation with ADP or thrombin receptor agonist peptide (TRAP). Then fluorescein isothiocyanate (FITC)-labeled secondary antibodies were added and analyzed on a Becton-Dickinson FACSort flow cytometer. In the hypercholesterolemic group, apo A-I binding to platelets was found to be significantly decreased after activation with TRAP (P<.05), but not after activation with ADP. In the control group, after platelet activation with ADP or TRAP, the apo A-I MFI values were not found to be significantly different from the values of resting platelets (P>.05). In this study, we demonstrated that apo A-I can bind to platelets, and this supports the hypothesis that apo A-I may play a major role in HDL binding to platelets.

Objective: The aim of this study is to assess thyrotropin stimulating hormone (TSH) response to thyrotropin releasing hormone (TRH) in patients with panic disorder (PD)., Method: The effects of TRH administration on the release of TSH were examined in 15 patients who met DSM-III-R criteria for PD and compared their test results with those of 15 normal control subjects. Blood samples were taken before TRH administration (baseline values) and at 15, 30 and 60 min., Results: delta max TSH values were lower in the panic disorder patients than in the control subjects. Using the criterion of delta max TSH < or = 7 mlU/l, nine of the 15 panic disorder patients and four of the 15 control subjects had a blunted TSH response to TRH., Conclusions: These results confirm the findings from earlier reports that patients with PD show blunted TSH response to TRH which is similar to that seen in depressed patients.

A goat antiserum was raised by immunization with the endoglycosidase fission product of porcine estrogen receptor. Its IgG fraction was employed for ascertaining the interrelationship of receptor forms extracted from three subcellular compartments of target cells and for comparing receptors from various species. Unspecific alignments of (non-immune) IgGs giving rise to soluble complexes were avoided by removal of the receptor entity responsible with carrier-attached trypsin. Coincubation of the estradiol-tagged tryptic receptor cores and immune IgG resulted in the formation of labelled precipitates and in the release of estradiol from its binding site, in every instance tested. A minimum of three common antigenic determinants must therefore exist not only on all porcine receptor forms, but also on human, ovine, bovine, rabbit, guinea-pig and rat estrogen receptors, pointing to a high degree of phylogenetic conservation.