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Biomedical subjects

A B Rawitch

Publications and source records attributed to A B Rawitch.

10 recordsLinked to original sources
PubMed1992

A neuropeptide Y (NPY)-related peptide is present in the river lamprey CNS.

Pancreatic polypeptide (PP)-like material from brain+spinal cord, and retina extracts of Lampetra fluviatilis was studied by HPLC and RIA. The brain+spinal cord extract showed a complex elution profile with multiple peaks of immunoreactivity. The retina extract showed a much simpler pattern with a single significant peak along with a trace of a second peak corresponding to the latest and penultimate peaks in the brain extract. Twenty-one out of 36 residues could be sequenced from the latest eluting peak in the brain extract. This sequence showed 81% identity with porcine neuropeptide (NPY) suggesting that both the brain/spinal cord and retina of the river lamprey contain a peptide homologous to NPY.

Amino Acid Sequence↗
PubMed1992

Thyroid peroxidase glycosylation: the location and nature of the N-linked oligosaccharide units in porcine thyroid peroxidase.

Highly purified, trypsin/detergent-solubilized thyroid peroxidase (TPO), prepared from pig thyroid tissue, was subjected to reduction and alkylation followed by trypsin digestion. The resulting peptides were fractionated using HPLC. Corresponding carbohydrate positive regions from three separate HPLC experiments were pooled and further chromatography was carried out to yield purified peptide suitable for sequence analysis and complete carbohydrate composition analysis. Four of the five putative sites for N-linked glycosylation were found to carry oligosaccharide units in which mannose and glucosamine were the sole or predominant sugars. Three of the four glycosylations occur at asparagine residues which are likely to be at beta turns or bends. The fifth putative glycosylation site could not be confirmed and may either be poorly glycosylated or escape glycosylation. All of the confirmed glycosylated sites occur in the N-terminal third of the TPO polypeptide chain, in the portion of the molecule believed to be extracellular. The isolation of at least two chromatographic forms of glycopeptide derived from each of the confirmed sites suggests microheterogeneity in the structure of the oligosaccharide units of thyroid peroxidase similar to that observed in many other glycoproteins.

Amino Acid Sequence↗
PubMed1988

An immunochemical study of avian pancreatic polypeptide: the nature of the principal epitope.

Structural features contributing to the antigenic recognition of the small globular hormone avian pancreatic polypeptide (APP) by a polyclonal antiserum have been defined using a solution phase radioimmunoassay technique. Cross-reactivity studies with PP homologues suggest that the surface residues within the alpha-helix of the peptide may be antigenic, whereas hydrophilicity and atomic mobility predictive methods implicate the molecules beta-turn region. Immunochemical data and circular dichroism measurements on a timed trypsin digest of APP indicate that the secondary structure of the alpha-helix is vital for the molecule's immunological competence. Immunoreactivities of iodinated derivatives of APP, as well as that of peptide fragments of APP and its homologues, support the importance of teritary structure involving the interaction of the polyproline and alpha helices. The highly mobile C-terminal residues 34-36 (His-Arg-Tyr-NH2) have been found by immunological analysis to be unimportant. Arginine residue 33, which has been conserved through vertebrate evolution, is a major antigenic contributor, since a large decrease in immunoreactivity, not accompanied by a significant change in conformation, was observed upon specific removal of this residue by carboxypeptidase B. These results are consistent with a "discontinuous" epitopic model for APP in which Arg-33 and exposed residues in the alpha-helix are principal components of an epitope or epitopes mediated by the secondary and tertiary structures of the molecule.

Animals↗
PubMed1979

Activity staining for glutamate and alanine dehydrogenases in polyacrylamide gels of varying porosity. A study of bovine placental enzyme forms.

A procedure has been developed for characterizing the various molecular forms of placental and liver glutamate dehydrogenases through a combination of activity staining and varying gel pore size in electrophoresis. At a concentration of 2 mg/ml, the bovine liver GDH remained associated in a very high molecular weight form, while the placental enzyme was substantially dissociated to a molecular species of near 240,000 molecular weight and several charge isomeric species of near 160,000 molecular weight. The general approach outlined here provides a means of definitely correlating the electrophoretic behavior of various dehydrogenase isozymes with both glutamate and alanine dehydrogenase activities and molecular size and should be applicable, even in crude extracts to other dehydrogenase enzymes which exhibit multiple forms or states of association.

Alanine↗
PubMed1977

Competition of delta 9-tetrahydrocannabinol with estrogen in rat uterine estrogen receptor binding.

Direct competition experiments with delta 9 -tetrahydrocannibinol (delta 9-THC) and estradiol in binding assays with rat uterine cytosol estrogen receptors showed that delta 9-THC was a weak, but nevertheless significant, competitor for binding to cytoplasmic estrogen receptors. These data support, at the molecular level, the observations that delta 9-THC has a weak estrogenic activity (at least the ability to bind to estrogen receptors). Moreover, estrogen-like binding suggests that delta 9-THC, acting at the level of estrogen receptor, causes a primary estrogenic effect rather than an indirect or secondary phenomenon.

Animals↗
PubMed1976

Chronic administration of delta-9-tetrahydrocannabinol to pregnant rats: studies of pup behavior and placental transfer.

Tritiated delta-9-tetrahydrocannabinol was administered orally to female rats throughout pregnancy at a dose level of 2 mg/kg/day. Chemical analysis of rat pup tissues indicated an average drug level near 20 ng/gm was attained via placental transfer. Although there was no teratogenicity, the pups showed both transient and relatively permanent behavioral effects. A deficit in acquisition of a passive avoidance response at 21 days of age was observed. This effect was not apparent during retraining and testing at 90 days of age. Rats whose dams had received the drug forced control animals to back out of a push tube in 67% of the tests at 21 days of age and 94% of the tests at 90 days of age.

Aggression↗