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Biomedical subjects

J D Barchas

Publications and source records attributed to J D Barchas.

At least 19 recordsLinked to original sources
PubMed1990

Amplified RNA synthesized from limited quantities of heterogeneous cDNA.

The heterogeneity of neural gene expression and the spatially limited expression of many low-abundance messenger RNAs in the brain has made cloning and analysis of such messages difficult. To generate amounts of nucleic acids sufficient for use in standard cloning strategies, we have devised a method for producing amplified heterogeneous populations of RNA from limited quantities of cDNA. Whole cerebellar RNA was primed with a synthetic oligonucleotide containing the T7 RNA polymerase promoter sequence 5' to a polythymidylate region. After second-strand cDNA synthesis, T7 RNA polymerase was used to generate amplified antisense RNA (aRNA). Up to 80-fold molar amplification has been achieved from nanogram quantities of cDNA. The amplified material is similar in size distribution to the parent cDNA and shows sequence heterogeneity as assessed by Southern and Northern blot analysis. Specific messages for moderate-abundance mRNAs for actin and guanine nucleotide-binding protein (G-protein) alpha subunits have been detected in the amplified material. By using in situ transcription to generate cDNA, sequences for cyclophilin have been detected in aRNA derived from single cerebellar tissue sections. cDNA derived from a single cerebellar Purkinje cell also has been amplified and yields material that hybridizes to cognate whole RNA and mRNA but not to Escherichia coli RNA.

Actins↗
PubMed1990

Influence of maternal proximity on behavioral and physiological responses to separation in infant rhesus monkeys (Macaca mulatta).

The effects of maternal proximity on the behavioral and physiological responses of infant rhesus macaques during 4 days of total or adjacent separations from the mother were studied. The 6 infants tested showed behavioral responses that differentiated the two separation conditions. Major differences were found in the quantity and quality of vocalizations, the occurrence of cage-biting and cage-shaking behavior, object exploration, and hunched and freezing postures. In particular, the structure of coo vocalizations clearly discriminated between the presence or the absence of the mother during separation. Cerebrospinal fluid (CSF) concentrations of dopamine and serotonin metabolites did not discriminate between the two separation conditions but showed a transient elevation at 24 hr after separation and were not different from baseline by 96 hr after separation. In contrast, both the plasma cortisol and the CSF norepinephrine metabolite responses tended to be greater and to persist for a longer period of time when infants were totally isolated. The results are discussed within the context of attachment and coping theories.

Animals↗
PubMed1989

Retraction.

Explore the source record for details and available documents.

Retraction Notice↗
PubMed1989

CSF phenylacetic acid and hostility in paranoid schizophrenia.

Lumbar cerebrospinal fluid concentrations of phenylacetic acid were significantly elevated in paranoid vs. nonparanoid schizophrenics. Further, phenylacetic acid concentrations were correlated with hostility. These results are consistent with the hypothesis that phenylethylamine, the proposed precursor of phenylacetic acid, plays a role in schizophrenia.

Adult↗
PubMed1988

Enhancement of dopamine metabolism in rat brain frontal cortex: a common effect of chronically administered antipsychotic drugs.

Administration of 4 antipsychotic drugs, haloperidol, chlorpromazine, thioridazine and clozapine, for 21 days elicited increased dopamine metabolism in frontal cortex of rat brain. Only clozapine failed to decrease the apparent firing rate of dopamine neurons in the striatum, as indexed by [homovanillic acid]/[dopamine]. These data support the hypotheses that frontal cortex dopamine neurons may be a common site for antipsychotic action while decreased release of dopamine in the striatum may be associated with the development of extrapyramidal side effects.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

In situ transcription: specific synthesis of complementary DNA in fixed tissue sections.

A technique, in situ transcription, is described, in which reverse transcription of mRNAs is achieved within fixed tissue sections. An oligonucleotide complementary to proopiomelanocortin (POMC) mRNA was used as a primer for the specific synthesis of radiolabeled POMC cDNA in fixed sections of rat pituitary, thus permitting the rapid anatomical localization of POMC mRNA by autoradiography. Intermediate lobe signal intensities were sensitive to dopaminergic drugs, demonstrating that the method can be used for studies of mRNA regulation. The transcripts may also be eluted from tissue sections for a variety of uses, including the identification and cloning of autoradiographically localized cDNAs from small amounts of tissue.

Animals↗
PubMed1988

19F magnetic resonance imaging and spectroscopy of a fluorinated neuroleptic ligand: in vivo and in vitro studies.

The bulk biodistribution of a trifluorinated neuroleptic (fluphenazine) was studied using 19F magnetic resonance imaging (MRI). Fifteen male Sprague-Dawley rats were injected with fluphenazine (120 mg/kg) and scanned in a G.E. CSI 2.0 tesla MRI system. The rats were killed following scanning and the brains were removed. The excised brains were then scanned using 1H and 19F MR techniques. The fluorinated neuroleptic was imaged at the injection site, spectroscopically detected in vivo in the head, and spectroscopically localized in the whole brain. These data suggest that in vivo 19F MRI of fluorinated agents is possible and could have clinical and research applications to the neurosciences.

Animals↗
PubMed1988

Methionine-enkephalin and thyrotropin-stimulating hormone are intimately related in the human anterior pituitary.

The tissue distribution and function of opioid peptides in humans is incompletely defined. We report here that, unlike that in other species, the human anterior pituitary gland contains high concentrations of methionine-enkephalin (met-enkephalin). The met-enkephalin immunoreactive material was isolated and identified as authentic met-enkephalin by fast atom bombardment-mass spectrometry and Edman degradation sequencing. The met-enkephalin was localized in a large subpopulation of TSH immunoreactive cells (thyrotrophs). No other proenkephalin-derived opioid peptides were found in the pituitary, and there was no overlap between proopiomelanocortin and met-enkephalin immunoreactive cells. These results suggest that the human anterior pituitary gland contains a novel met-enkephalin precursor and a possible role for met-enkephalin in regulating human thyroid function.

Adolescent↗
PubMed1987

Expression of opioid peptides in tumors.

We looked for opioid peptides and their precursors in 108 tumors of both neuroendocrine and nonneuroendocrine origin, using a monoclonal "pan-opioid" antibody, 3-E7, which recognizes the tetrapeptide Tyr-Gly-Gly-Phe (the sequence responsible for pharmacologic activity in all known opioid peptides), in conjunction with polyclonal antibodies directed against representative peptides of each of the three precursors (alpha-endorphin, [met]enkephalin-Arg-Gly-Leu, and dynorphin B). Using the avidin-biotin immunoperoxidase technique, we observed consistent cytoplasmic immunoreactivity (at least focally) in all of 15 adrenal pheochromocytomas, all of 6 thyroid medullary carcinomas, and all of 5 pituitary adenomas. Opioid staining was also observed in parathyroid adenomas (8 of 9), pancreatic islet-cell tumors (7 of 10), carcinoid tumors from various sites (18 of 26), and paragangliomas (1 of 2). There was no immunoreactivity in pulmonary small-cell carcinomas, Merkel-cell tumors of skin, neuroblastomas, or any of the non-neuroendocrine tumors examined. The expression of alpha-endorphin, [met]enkephalin-Arg-Gly-Leu, and dynorphin B varied from tumor to tumor; however, positive staining with the "pan-opioid" antibody was found in each tumor containing at least one of the three precursors. Opioid peptide immunoreactivity was also detected in non-neoplastic cells of the adrenal medulla, pancreatic islets, pituitary, intestinal and bronchial mucosa, and intestinal myenteric plexuses. We conclude that opioid expression within tumors is most likely due to enhanced expression of a normal cell product and that opioid peptides are useful markers of neuroendocrine differentiation in many tumors.

Antibodies, Monoclonal↗
PubMed1987

Pharmacological properties of a proenkephalin A-derived opioid peptide: BAM 18.

BAM 18 is a derivative of the opioid precursor proenkephalin A. Although it exists in rat and guinea-pig brain in relatively high concentrations, its physiological function is presently unknown. In the present study we have determined the opioid receptor selectivity of this peptide using radioligand binding and peripheral tissue bioassay. When selective binding conditions were used, BAM 18 bound to the mu opioid receptor with an affinity three times that of the kappa opioid receptor and over 10 times that of the delta opioid receptors (Ki = 0.29, 0.75, and 3.2 nM respectively). BAM 18 also displayed mixed receptor selectivity in in vitro bioassay. Ke values for naloxone antagonism of BAM 18 agonist activity in the electrically stimulated guinea-pig ileum and the mouse vas deferens were 4.3 and 9.9 nM, respectively. These data indicate that BAM 18 binds to all three opioid receptor subtypes with a selectivity profile of mu greater than kappa greater than delta.

Animals↗
PubMed1987

TRH stimulation test and depression.

A thyrotropin-releasing hormone (TRH) stimulation test was performed in 52 male inpatients with major depressive disorder. Twenty-nine percent of the 52 subjects had a delta thyroid-stimulating hormone (delta TSH) less than 5 microU/ml. The cerebrospinal fluid (CSF) amine metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5HIAA), were measured in 29 subjects, and a dexamethasone suppression test (DST) was performed in 48 subjects. Of the three CSF amine metabolites, only MHPG correlated significantly with baseline TSH and none correlated with delta TSH. The baseline TSH correlated positively with the TSH response at 30 minutes. Neither baseline TSH nor delta TSH correlated with cortisol levels before or after dexamethasone. The correlation between CSF MHPG and serum TSH suggests a relationship between central norepinephrine and baseline TSH.

Adult↗