In vivo and in vitro serine/threonine phosphorylations of epidermal growth factor receptor upon entry into the cell cycle.

Protein phosphorylation and dephosphorylation is one of the main mechanisms of cell cycle regulation. This study examines the modulation of epidermal growth factor receptor phosphorylation as cells emerge from quiescence and enter the S phase of the cell cycle. The epidermal growth factor receptor is phosphorylated primarily on serine and threonine, but not on tyrosine residues, in an S phase-dependent fashion, as determined by phosphoamino acid analysis and anti-phosphotyrosine immunoblotting.

Factors affecting erythropoietin production and correction of anemia in kidney transplant recipients.

Anemia does not correct in many kidney transplant recipients, probably due to iron deficiency or inadequate erythropoietin (Epo) production. We evaluated effects of iron (Fe) availability on correction of anemia in renal transplant recipients and sought to characterize patterns of early Epo production by transplanted kidneys as related to peritransplant factors. In a prospective randomized trial, 51 consecutive renal transplant patients were followed for 6 months.

Inhibition of agonist-induced rise in platelet Ca2+ by antithrombotic nipecotamides.

The effects of three structural types of nipecotamides and their stereoisomers on collagen-induced aggregation and intraplatelet ionized calcium ([Ca2+]i) rise in human platelets were evaluated using aequorin as the [Ca2+]i indicator. The orders of potencies of racemic nipecotamides were different when collagen was the agonist compared with those obtained using ADP. It is suggested that in addition to their earlier hypothesized interactions with platelet anionic phospholipids of the plasma and organelle membranes, nipecotamides may, in addition, act at other receptor sites.

Effects of dietary cholesterol on hepatic metabolism of free fatty acid and secretion of VLDL in the hamster.

We reported previously that dietary cholesterol produces hepatic steatosis, increased secretion of the VLDL, and hypertriglyceridemia in the rat, the result of reduced oxidation of fatty acids, stimulation of fatty acid synthesis, and increased incorporation of fatty acid into hepatic triglyceride. The present study was conducted to determine whether these regulatory actions of dietary cholesterol on fatty acid metabolism also occur in the Golden Syrian hamster. In the hamster, dietary cholesterol (0.

Cerebral blood flow responses to indomethacin in awake newborn pigs.

The prostaglandin H-synthase inhibitor indomethacin decreases cerebral blood flow (CBF) in newborn pigs. The duration of this effect on CBF has not been established in piglets in the awake state. The purpose of the study was to determine in awake piglets the duration of cerebral vascular responses to a single dose of indomethacin and the CBF responses to a second dose of indomethacin.

Antiplatelet activity of nipecotamides in experimental thrombosis in mice.

A group of nipecotamides (3-carbamoylpiperidines) were designed, synthesized, and evaluated for their ability to protect platelets from induced aggregation. An in vivo mouse thrombosis model was used to determine the protection afforded by these compounds from sudden thrombotic death induced by intravenous collagen plus epinephrine. Enantioselectivity appears to play a pivotal role in determining the activity of these compounds.

Stimulation of fatty acid biosynthesis by dietary cholesterol and of cholesterol synthesis by dietary fatty acid.

We reported previously that dietary cholesterol produces hypertriglyceridemia in the rat, accompanied by reduced oxidation and increased incorporation of exogenous fatty acid into hepatic triglyceride and increased secretion of very low density lipoprotein. We now report that dietary cholesterol also increases net hepatic fatty acid synthesis and the incorporation of newly synthesized fatty acid into hepatic triglyceride in vivo. Male rats were fed a cholesterol-free, semisynthetic diet (5% [w/w] corn oil) for 7 days, or the same diet supplemented with 0.

The distribution of GABA-containing perikarya, fibers, and terminals in the forebrain and midbrain of pigeons, with particular reference to the basal ganglia and its projection targets.

Immunohistochemical techniques were used to study the distributions of glutamic acid decarboxylase (GAD) and gamma-aminobutyric acid (GABA) in pigeon forebrain and midbrain to determine the organization of GABAergic systems in these brain areas in birds. In the basal ganglia, numerous medium-sized neurons throughout the striatum were labeled for GABA, while pallidal neurons, as well as a small population of large, aspiny striatal neurons, labeled for GAD and GABA. GAD+ and GABA+ fibers and terminals were abundant throughout the basal ganglia, and GABAergic fibers were found in all extratelencephalic targets of the basal ganglia.

Bacteriophage Mu Mor protein requires sigma 70 to activate the Mu middle promoter.

Transcription during the bacteriophage Mu lytic cycle occurs in three phases: early, middle, and late. Middle transcription requires the early gene product Mor for its activation. Mor protein overproduction was accomplished by fusing the mor gene to an efficient phage T7 promoter and translation initiation region.

Effect of choroidal and ciliary nerve transection on choroidal blood flow, retinal health, and ocular enlargement.

Our previous studies suggested that reduced choroidal blood flow (CBF) occurs with manipulations that yield myopic eye growth and that these reductions are primarily a consequence of the ocular enlargement. We could not entirely rule out the possibility, however, that reductions in CBF are at least to some extent antecedent and causal to the ocular enlargement. We therefore in the present study examined the effects on eye size of artificially reducing CBF by unilaterally transecting the choroidal nerves of the ciliary ganglion in four-day-old chicks.

Dietary cholesterol stimulates hepatic biosynthesis of triglyceride and reduces oxidation of fatty acids in the rat.

Experiments were conducted in the intact rat and in the isolated, perfused rat liver to investigate the possibility that the increase in the concentration of hepatic triglyceride and increase in the secretion of the very low density lipoprotein (VLDL)-triglyceride (TG) resulting from addition of cholesterol to the diet are due to stimulation of synthesis of triglyceride, reduced fatty acid oxidation, or both. Male rats were fed for 7 days with either a cholesterol-free diet to which 5% (w/w) corn oil was added, or with the same diet supplemented with 0.5% cholesterol.

Neurotransmitter organization and connections of turtle cortex: implications for the evolution of mammalian isocortex.

Telencephalic cortex in turtles is a simple three layered-structure. The dorsal most part of this structure is thought to resemble the reptilian forerunner of at least parts of mammalian isocortex. This dorsal part of turtle cortex contains several functionally distinct regions that show similarity in their connections and function to specific areas in mammalian isocortex.

Choroidal blood flow is reduced in chicks with ocular enlargement induced by corneal incisions.

We have previously reported decreased choroidal blood flow (CBF) associated with goggle-induced ocular enlargement and myopia. It was uncertain, however, if this change in CBF was related to the occurrence of ocular enlargement or the increased ocular temperature produced by the goggle. We therefore used corneal surgery-induced ocular enlargement that eliminated the thermal effects observed with goggles to investigate the effects of ocular enlargement on CBF.

Reduction in choroidal blood flow occurs in chicks wearing goggles that induce eye growth toward myopia.

Goggles that degrade the retinal image produce axial enlargement of the ocular globe and large myopic refractive errors. Many authors have assumed that visual image degradation itself leads to myopia. Hodos and co-authors have shown, however, that goggled eyes in chicks are considerably warmer than normal.

Enantioselective antiplatelet actions of nipecotamides.

Two synthetic racemic nipecotamides, 1-decyl-3-(N,N- diethylcarbamoyl)piperidine hydrobromide (1) and alpha, alpha'-bis[3-(N-benzyl-N-methylcarbamoyl)piperidino]-p-xylene dihydrobromide (2) were resolved on a chiral alpha 1-acid glycoprotein semipreparative HPLC column. Thus, rac.1 was resolved into two enantiomers 1A-(+) and 1B-(-); rac.

Mutagenic oligonucleotide-directed PCR amplification (Mod-PCR): an efficient method for generating random base substitution mutations in a DNA sequence element.

Saturation mutagenesis is one approach for determining the contributions of individual base pairs to the structure and function of defined DNA sequence elements. In this paper, we describe a novel method for saturation mutagenesis involving PCR amplification with degenerate synthetic oligonucleotides as primers. The degeneracy is confined to a specific target within the primer by mixing a low percentage of the three non-wild type (non-WT) nucleotide precursors with WT at specific positions during primer synthesis.

Overall signal sequence hydrophobicity determines the in vivo translocation efficiency of a herpesvirus glycoprotein.

We have described three mutant strains of Pseudorabies virus that contain mutations in the signal sequence coding region of a nonessential envelope glycoprotein, gIII. The alterations disrupt, truncate, or eliminate the hydrophobic core domain of the signal sequence. Each mutant was assayed for its ability to promote the translocation of gIII across the endoplasmic reticulum membrane and the subsequent localization of the mature form of the glycoprotein to the infected cell surface or the virus envelope.

In vitro and in vivo activities of the novel antiplatelet agent alpha,alpha'-bis[3-(N,N-diethylcarbamoyl)piperidino]-p-xylene dihydrobromide.

In an effort to develop compounds with high antithrombotic activity and minimal toxicity, our laboratory has synthesized a number of nipecotamides. The effectiveness of one of these compounds, alpha,alpha'-bis[3-(N,N-diethylcarbamoyl)piperidino]-p-xylene dihydrobromide (A-1), in inhibiting both in vitro and in vivo platelet aggregation is reported here, along with its acute toxicity. The IC50 of A-1 in in vitro ADP- and PAF-induced platelet aggregation was 44.

The neurotensin-related hexapeptide LANT6 is found in retinal ganglion cells and in their central projections in pigeons.

Previous biochemical and immunohistochemical studies have shown that the neurotensin-related hexapeptide LANT6 is widespread and abundant in the avian nervous system. In the present study, immunohistochemical techniques were used to show that LANT6 is present in numerous cells of the retinal ganglion cell layer in pigeons. Consistent with the possibility that these LANT6+ retinal cells might be retinal ganglion cells, it was found that (1) the distribution of LANT6+ fibers and terminals in the central retinal target areas matched the distribution of central retinal projections; (2) the LANT6+ fibers and terminals are eliminated from retinal target areas by transection of the contralateral optic nerve; and (3) LANT6+ retinal cells in the ganglion cell layer can be retrogradely labeled by injections of fluorogold in the tectum.

Molecular determinants of the platelet aggregation inhibitory activity of carbamoylpiperidines.

A series of alpha,alpha'-bis[3-(N,N-dialkylcarbamoyl)piperidino]-p- xylenes were synthesized and tested for their inhibitory activity on ADP-induced aggregation of human platelets. A parabolic curve was obtained when log 1/C (activity) was plotted against log P (octanol/water partition coefficient). Using this as a model, a new analogue, alpha,alpha'-bis-[3-(N-methyl-N-butylcarbamoyl)piperidino]-p-xylen e (3g), was synthesized with a predicted IC50 of 25 microM.

Transcriptional regulation of the apolipoprotein B100 gene: purification and characterization of trans-acting factor BRF-2.

Apolipoprotein B100 (apoB), the only protein of low-density lipoprotein, is produced primarily in the liver and serves as a ligand for the low-density lipoprotein receptor. Hepatic cell-specific expression of the human apoB gene is controlled by at least two cis-acting positive elements located between positions-128 and -70 (H. K.

Resistance to N-benzyladriamycin-14-valerate in mouse J774.2 cells: P-glycoprotein expression without reduced N-benzyladriamycin-14-valerate accumulation.

N-Benzyladriamycin-14-valerate (AD 198) is a highly lipophilic analogue of Adriamycin with novel cytotoxic mechanisms, greater in vivo antitumor activity, and the ability to circumvent multidrug resistance due to P-glycoprotein-mediated drug efflux or decreased topoisomerase II activity. To identify the mechanism(s) which may confer AD 198 resistance, J774.2 mouse macrophage-like cells were selected for growth in cytotoxic levels of AD 198 (AD 198R).

An immunohistochemical study of the telencephalon of the senegal bichir (Polypterus senegalus).

The telencephalon in ray-finned fish (actinopterygians) is everted, in contrast to the evaginated telencephalic hemispheres in all other vertebrates. In the more derived ray-finned fish, the teleosts, proliferation of neurons and their migration from the ependymal zone of the pallium renders comparisons between telencephalic cell groups of the teleosts and members of other vertebrate groups extremely difficult. The telencephalon of Polypterus (a primitive living ray-finned fish), although everted, is cytoarchitecturally much simpler than that of teleosts.