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Biomedical subjects

A Roy

Publications and source records attributed to A Roy.

At least 451 records · Page 25Linked to original sources
PubMed1984

The complete nucleotide sequence of the adenylate cyclase gene of Escherichia coli.

The complete nucleotide sequence of the cya gene from E. coli was determined. The gene encodes a polypeptide consisting of 848 amino acid residues with a calculated molecular weight of 97,542. The deduced protein structure reveals that cyclase is comprised of two domains, an amino-terminal region exhibiting catalytic activity and a carboxy-terminal region possibly carrying regulatory function. The frequent appearance of rare codons in the beginning of the gene as well as the sequence duplication in the promoter-initiator region suggest possible regulation(s) at the translational level. An unknown gene (cyaX) which seems to code for a very hydrophobic protein was found following the cya gene. Sequence analysis suggests that the cyax is a part of the cya operon.

Adenylyl Cyclases↗
PubMed1984

Neuroleptic-induced decrease in plasma homovanillic acid and antipsychotic activity in schizophrenic patients.

Plasma-free homovanillic acid, a major metabolite of dopamine, was measured in chronically ill schizophrenic patients both before and during treatment with the antipsychotic phenothiazine, fluphenazine. Neuroleptic treatment was associated with a significant time-dependent decrease in plasma homovanillic acid from pretreatment values, which were significantly elevated when compared with those of age- and sex-matched healthy control subjects. Further, both the absolute concentrations as well as the neuroleptic-induced reductions in plasma homovanillic acid determined over 5 weeks of neuroleptic treatment were statistically significantly correlated with ratings of psychosis and improvement in psychosis, respectively. These findings suggest that the delayed effects of neuroleptic agents on presynaptic dopamine activity may more closely parallel their therapeutic actions than do their immediate effects in blocking postsynaptic dopamine receptors and that a decrease in dopamine "turnover" may be responsible for their antipsychotic effects.

Adult↗
PubMed1984

Identification of the Escherichia coli cya gene product as authentic adenylate cyclase.

The Escherichia coli cya gene has been fused in the same register with the lacZ gene. The corresponding hybrid cya-lacZ gene is expressed as a bifunctional protein that exhibits both adenylate cyclase and beta-galactosidase activities, thus proving that cya is the structural gene for adenylate cyclase. The hybrid protein was purified to homogeneity and has been used to raise antibodies that recognize wild-type adenylate cyclase. Finally, the protein has been submitted to amino acid sequence analysis. It has been found that the first ten amino acids fit the predicted sequence obtained from DNA sequence analysis, thus substantiating the prediction that the cya translation initiation codon is UUG .

Adenylyl Cyclases↗
PubMed1984

Structure of the capsular polysaccharide from Streptococcus pneumoniae type 23.

The capsular polysaccharide from Streptococcus pneumoniae Type 23 (S-23) was found to contain D-galactose, D-glucose, L-rhamnose, glycerol, and phosphorus in the ratios of 1:1:2:0.6:1. Methylation analysis provided information about the linkages of the different sugar units. The sequence of the different sugar residues was confirmed by Smith degradation. Oxidation of S-23 with chromium trioxide indicated that all of the sugar units have the beta configuration. The results suggest the following structure for the repeating unit. (formula; see text)

Carbohydrate Conformation↗
PubMed1984

Effect of some monoamine oxidase inhibitors and cyclic-AMP on plasma fibrinogen level of rats.

In vivo administration of short acting or long acting inhibitor of monoamine oxidase elevates plasma fibrinogen level in rats. These inhibitors cannot elevate plasma fibrinogen level in rats pretreated with p-chlorophenyl alanine and alpha-methyl-meta-tyrosine, inhibitors of catecholamine and serotonin formation respectively. However, administration of epinephrine or serotonin under the above experimental condition elevates fibrinogen level indicating rise of biogenic monoamine, even for a short period, is a good stimulus for increase of plasma fibrinogen. Dibutyryl cyclic-AMP (c-AMP) also elevates fibrinogen level and shows additive effect with theophylline or serotonin.

Animals↗
PubMed1984

The effects of ceruletide in schizophrenia.

Eight neuroleptic-resistant schizophrenic patients were treated with ceruletide diethylamine, a cholecystokininlike peptide, in a placebo-controlled, double-blind, cross-over study. Ceruletide or placebo was administered intramuscularly twice a day for four consecutive days while patients received a constant dose of fluphenazine hydrochloride. Cholecystokinin octapeptide was also administered to four different schizophrenic patients in a double-blind, cross-over study. Cholecystokinin or placebo was administered as a slow intravenous infusion daily for four days. There were no changes in either the positive or negative symptoms of schizophrenia between the periods of placebo, ceruletide, or cholecystokinin administration. Furthermore, there was no tendency for the patients' conditions to either improve or worsen during the course of ceruletide or cholecystokinin treatment. In contrast to previous reports from uncontrolled studies, cholecystokininlike peptides appear to be devoid of antipsychotic properties when administered parenterally.

Adult↗
PubMed1984

Psychiatric implications of basic and clinical studies with corticotropin-releasing factor.

Corticotropin-releasing factor (CRF) is a newly sequenced neuropeptide thought to be a principal stimulus to pituitary corticotropin (ACTH) secretion. Evidence obtained from laboratory animals and primates is reviewed which indicates that CRF not only stimulates the pituitary-adrenal axis but also influences several aspects of CNS function which may be of relevance to psychiatric illness. Clinically, experience in administering ovine CRF to more than 150 individuals shows that CRF can be helpful in resolving differential diagnostic dilemmas in patients with various disorders of the hypothalamic-pituitary-adrenal axis and in furthering an understanding of the pathophysiology of conditions such as Cushing's disease and depression.

Adrenocorticotropic Hormone↗
PubMed1984

Risk factors for depression in Canadians.

In a matched controlled study 72 Canadian patients with a major depressive episode were compared with non-depressed and never depressed orthopedic patients. Significantly more of the depressives had parental loss before 17 years of age, a poor marriage before the onset of depression and a family history of depression.

Adolescent↗
PubMed1984

Suicide in recurrent affective disorder patients.

In a matched controlled study manic depressive patients who suicided were compared with those who did not suicide. Significantly more of those who suicided lived alone, had early parental loss, had attempted suicide in the past, and were depressed and suicidal at their last admission. The period after discharge was found to be a time of increased risk.

Adult↗
PubMed1984

Attempted suicide in chronic schizophrenia.

In a consecutive series of 127 chronic schizophrenics admitted to hospital, 70 (55.1 per cent) had attempted suicide. When compared with the chronic schizophrenics who had not attempted suicide, significantly more of the attempters had had a major depressive episode (45.7 per cent) and had received antidepressant medication (65.7 per cent). They also had histories of significantly more psychiatric admissions (a mean of 5.4 compared with 3.6). These findings are discussed.

Adolescent↗
PubMed1984

Do neuroleptics cause depression?

To investigate the etiology of depression occurring in the course of schizophrenia, 18 chronic schizophrenic outpatients with a major depressive episode were matched with nondepressed schizophrenic outpatient controls. There was no significant difference on mean equivalent daily dosage of chlorpromazine between the depressed and nondepressed schizophrenic groups. Thus, neuroleptics do not appear to induce depressive disorder in chronic schizophrenic patients.

Adult↗
PubMed1983

Two functional domains in adenylate cyclase of Escherichia coli.

To study the regulation of Escherichia coli adenylate cyclase, plasmids that carry part of the cya gene, as well as plasmids containing hybrid genes having part of cya fused to part of lacZ, were constructed. This allowed us to propose that the enzyme is made of at least two well-defined domains. The NH2 terminus carries the ATP leads to cAMP catalytic activity, whereas the COOH-terminal end corresponds to a regulatory polypeptide domain.

Adenylyl Cyclases↗
PubMed1983

Family history of suicide.

Among 243 patients with a family history of suicide, almost half (118 [48.6%]) had attempted suicide, more than half (137 [56.4%]) had a depressive disorder, and more than a third (84 [34.6%]) had recurrent affective disorder. These 243 patients with a family history of suicide were compared with 5,602 patients with no family history of suicide. A family history of suicide was found to significantly increase the risk for an attempt at suicide in patients with a wide variety of diagnoses: schizophrenia, unipolar and bipolar affective disorders, depressive neurosis, and personality disorders.

Adult↗