As a first step in understanding how the supply of the neurotransmitter histamine is maintained in a photoreceptor, we followed the uptake and metabolism of the immediate precursor of histamine, histidine. [3H]Histidine taken up into photoreceptors and glia was detected using autoradiography, and synthesis of [3H]histamine from [3H]histidine was assayed with thin-layer chromatography. Photorece...

Adenosine uptake sites have been characterized and localized in guinea pig and pointer dog brain by in vitro autoradiography, using as probes 3H-nitrobenzylthioinosine (3H-NBI) and the recently available 3H-dipyridamole (3H-DPR). In guinea pig brain and, to a lesser extent, in pointer dog brain, 3H-DPR was found to label more high-affinity binding sites than 3H-NBI and NBI inhibited 3H-DPR bind...

Barium tantalum oxynitride (BaTaO 2 N), a photocatalyst active during one-step-excitation overall water splitting under visible light, was synthesized by NH 3 -based nitridation of mixture BaCO and amorphous Ta O 5 ·3H O.

The biotransformation of pregnenolone-7alpha-3H and of progesterone-7alpha-3H by porcine fetal and maternal adrenal homogenates at 56 and 112 days of pregnancy and of dehydroepiandrosterone-7alpha-3H by fetal adrenal homogenates has been investigated in vitro. Both pregnenolone-7alpha-3H and progesterone-7alpha-3H were metabolized extensively by maternal adrenal preparations, the principal radi...

When myo-[3H]inositol-prelabelled primary-cultured murine bone-marrow-derived macrophages were challenged with platelet-activating factor (PAF; 200 ng/ml), there was a rapid (2.5-fold at 10 s) rise in the intracellular concentration of D-myo-[3H]inositol 1,4,5-trisphosphate, followed by a rise in myo-[3H]inositol tetrakisphosphate. myo-[3H]Inositol tetrakisphosphate fractions were isolated by h...

The appearance of [11,12-3H]lipoxin A4 (LXA4) specific binding sites was examined with human acute promyelocytic leukemic cell line 60 (HL-60) cells exposed to either retinoic acid, phorbol 12-myristate 13-acetate (PMA), or dimethyl sulfoxide (DMSO). All three agents induced a threefold to fivefold increase in the expression of specific [11,12-3H]LXA4 binding. Similar results were obtained in p...

The phencyclidine analogue [3H](1-[2-thienyl]cyclohexyl)piperidine (3H-TCP) binds to the ion channel associated with the N-methyl-D-aspartate receptor channel complex. In vitro autoradiography indicates that the distribution of 3H-TCP binding in brain closely parallels that of [3H]glutamate binding to the N-methyl-D-aspartate receptor. In nine 7-day-old rats, an acute focal hypoxic-ischemic ins...

Low density lipoprotein (LDL) metabolism by human skin fibroblasts was studied using LDL labeled in the neutral lipid fraction with a nonhydrolysable cholesteryl ester analogue 3H-cholesteryl linoleyl ether (3H-CLE-LDL). LDL uptake could be quantitated accurately using 3H-CLE-LDL, since the label accumulated intracellularly due to its resistance to hydrolysis. 3H-CLE-LDL was taken up via apo B,...

Keratinocytes differentiating in vitro exhibit greater cytosolic capacity for retinoic acid synthesis from retinol or retinaldehyde as compared to nondifferentiated cells (Siegenthaler et al. 1990. Biochem. J. 268: 371-378), and increased expression of CRABP-II (Siegenthaler et al. 1988. Exp. Cell Res. 178: 114-126). Based on these observations, the content and disposition of [3H]retinoic acids...

Background: Cytosolic double-stranded RNA (dsRNA) is an important ‘molecular signature’ for the detection of intracellular viral infections. Although intracellular dsRNA is a known potent inducer of apoptosis, the optimal time and dose for the onset of dsRNA-mediated apoptosis have not been studied in detail. Objective: To perform an accurate temporal assessment of the cell death responses in d...