Gel matrix vehicles for growth factor application in nerve gap injuries repaired with tubes: a comparison of biomatrix, collagen, and methylcellulose.

The repair of nerve gap injuries with tubular nerve guides has been used extensively as an in vivo test model in identifying substances which may enhance nerve regeneration. The model has also been used clinical nerve repair. The objective of this study was to compare three different gel matrix-forming materials as potential vehicles for growth factors in this system.

Evidence for hypoxia-induced, programmed cell death of cultured neurons.

Apoptosis, a form of cell death ("programmed" cell death) in which the nucleus and cytoplasm shrink and often fragment, serves to eliminate excessive or unwanted cells during remodeling of embryonic tissues, during organ involution, and in tumor regression. In acute pathological states, such as ischemia, the cells tend to swell and lyse--a process called necrosis. We hypothesize that the delayed neural death clinically associated with hypoxia may, in part, represent apoptosis.

Cytokine-induced programmed death of cultured sympathetic neurons.

Programmed cell death (PCD) of sympathetic neurons is inhibited by nerve growth factor. However, factors that induce PCD of these cells are unknown. Leukemia inhibitory factor (LIF) and ciliary neurotrophic factor, neuropoietic cytokines known to regulate sympathetic neuron gene expression, were examined for effects on survival of cultured sympathetic neurons.

Heterogeneity in gap junction expression in astrocytes cultured from different brain regions.

Heterogeneity among astrocytes suggests that their role in the central nervous system is more complex than is commonly recognized. This paper describes just such a functional difference, comparing gap junctions in astrocytes derived from two brain regions. Astrocytes, both in situ and in culture, employ gap junctions as a means of intercellular communication.

Cultured astrocytes release proenkephalin.

Astrocytes as well as neurons express the mRNA encoding the opioid peptide precursor, proenkephalin. In neurons proenkephalin is cleaved intracellularly to yield smaller, bioactive peptides such as Met-enkephalin and Leu-enkephalin. By contrast, utilizing a combination of radioimmunoassay and chromatographic analysis, we report here that astrocytes cultured from neonatal rat brain contain primarily unprocessed proenkephalin and only small amounts of Met-enkephalin.

Region-specific regulation of preproenkephalin mRNA in cultured astrocytes.

Regulation of preproenkephalin (PPE) mRNA was examined in astrocytes cultured from several regions of the neonatal rat brain. Astrocytes from these regions expressed differing levels of PPE mRNA, with higher levels in astrocytes from the hypothalamus followed by frontal cortex and striatum. Further, PPE mRNA was regulated differently in hypothalamic than in striatal glia.

Purification and partial amino acid sequence of bovine adrenal phenylethanolamine N-methyltransferase: a comparison of nucleic acid and protein sequence data.

Recently, we have reported the isolation and characterization of a putative genomic DNA clone encoding bovine adrenal phenylethanolamine N-methyltransferase (PNMT) (Batter et al., 1988). However, the lack of primary amino-acid sequence data for this enzyme precluded a definitive proof of the authenticity of this clone.

The complete nucleotide sequence and structure of the gene encoding bovine phenylethanolamine N-methyltransferase.

A cDNA clone for bovine adrenal phenylethanolamine N-methyltransferase (PNMT) was used to screen a Charon 28 genomic library. One phage was identified, designated lambda P1, which included the entire PNMT gene. Construction of a restriction map, with subsequent Southern blot analysis, allowed the identification of exon-containing fragments.

Aberrant recombination events in B cell lines derived from a kappa-deficient human.

We have analyzed the structure of Ig kappa chain genes in B cell lines derived from a human individual who cannot synthesize any kappa chains, and whose Igs all contain lambda chains (1). We have characterized secondary DNA recombination events at two kappa alleles which have undergone misaligned V-J recombinations. One such secondary recombination has joined the flanking sequences of a V kappa and a J kappa 2 gene segment as if it were the reciprocal product of a V-J kappa 2 recombination, and resulted in the displacement of the recombined VJ kappa 1 gene segments from the C kappa locus.

Sulfanilic acid: behavioral change related to azo food dyes in developing rats.

The effects of sulfanilic acid, a major azo food dye metabolite, were studied in normal developing rat pups and pups treated with 6-hydroxydopamine (60HDA). Chronic daily intraperitoneal injection of sulfanilic acid during the first postnatal month elicited hyperactivity and impaired shock escape performance in vehicle pups. No differences were noted in 60HDA treated rat pups receiving sulfanilic acid.

Effects of bromocriptine in developing rat pups after 6-hydroxydopamine.

The effects of low (0.5 mg/kg) and high (2.0 mg/kg) doses of bromocriptine (BCR) on activity and escape performance were examined during the first month of postnatal life in normal developing rat pups and littermates treated at 5 days of age with a combination of desmethylimipramine and 6-hydroxydopamine (6-OHDA).

Determination of indoles and catechols in rat brain and pineal using liquid chromatography with fluorometric and amperometric detection.

Tryptophan, serotonin, 5-hydroxyindoleacetic acid, and homovanillic acid were determined in rat brain by the direct injection of a centrifuged tissue homogenate into a liquid chromatographic-fluorometric/amperometric system. The above indoles, along with melatonin, were also determined in single rat pineal glands. The utility of the system in determining several additional catechols and idoles in brain was examined.