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Biomedical subjects

V B Tuason

Publications and source records attributed to V B Tuason.

At least 55 records · Page 3Linked to original sources
PubMed1982

MMPI state dependency during the course of bipolar psychosis.

Minnesota Multiphasic Personality Inventory (MMPI) profiles completed during unambiguous manic, depressed, and euthymic periods were compared in a sample of 22 bipolar (manic-depressive) patients, 13 females and 9 males, drawn from an outpatient psychiatry clinic; each patient was "multiplex-selected" in that each had a first-degree relative with a severe psychiatric disorder. Both the manic and depressed phase MMPIs revealed significant and prototypical signs of psychopathology corresponding with the clinical picture. In contrast, the mean remission profile was entirely within normal limits. At least in some individuals, bipolar disorder seems to be associated with complete restitution of normality.

Adult↗
PubMed1982

Use of renal enzymes to evaluate nephrotoxicity in lithium treated patients.

N-acetyl-beta-glucosaminadase (NAG) is a renal enzyme which is an early, sensitive and reliable indicator of renal damage. NAG assays of midstream spot urines were not significantly different in a group of controls when compared to patients starting lithium for the first time, or to a group of patients who had been taking lithium for more than one year. However, a small number of lithium-treated patients may have evidence of renal damage, identifiable by NAG assay.

Acetylglucosaminidase↗
PubMed1982

A comparison of peripheral and central human muscarinic cholinergic receptor affinities for psychotropic drugs.

A peripheral model offers a valuable research tool for the investigation of central cholinopathic disorders. The in vitro affinities of several psychotropic drugs for the muscarinic cholinergic binding sites of human caudate and erythrocyte were compared in competition with a tritiated antagonist (quinuclidinyl benzilate). The relative affinities of the drugs for both tissues were strikingly similar. Thus, the erythrocyte muscarinic receptor may represent an accessible in vitro assay for the characterization of central cholinopathic states.

Binding, Competitive↗
PubMed1982

RDC depressive subtypes: are they valid?

Ninety patients meeting the Research Diagnostic Criteria (RDC) for major depressive disorder were further diagnosed using the RDC depressive subtypes. Patients with specific RDC subtype diagnoses were compared to those who did not meet the subtype criteria on several variables, including family history, illness course, work history, social history, previous treatment, quality of remissions, and symptomatology. Several items significantly differentiated patients diagnosed as primary, psychotic, and situational from those not so diagnosed: this supports the validity of these subtype categories. However, the study did not support the validity of the incapacitated, agitated, and retarded subtypes. No conclusions could be drawn regarding the endogenous, simple, or recurrent unipolar depressive subtypes.

Adult↗
PubMed1981

Stimulation of guanylate cyclase by EDTA and other chelating agents.

The partially purified soluble guanylate cyclase (GTP pyrophosphatelyase(cyclizing), EC 4.6.1.2) from human caudate nucleus is stimulated from 2 to 4-fold by metal chelating agents. EDTA (K 1/2 - 4.8 microM) is more potent than CDTA (K 1/2 = 13.2 microM) or EGTA (K 1/2 = 21.8 microM) at stimulating activity. Stimulation by chelating agents is apparently not due to removal of inhibitory divalent cations which contaminate the enzyme or reaction mixture. EDTA increases guanylate cyclase activity in part by increasing the affinity of the enzyme for the substrate (MgGTP) 10-fold. Dopamine inhibits partially purified guanylate cyclase in the presence or absence of EDTA. Dopamine increases the Ka of guanylate cyclase for the activator, free Mn2+, more than 50-fold, from 3 to 150 microM.

Caudate Nucleus↗
PubMed1981

Dissociation of smooth-pursuit and saccadic eye tracking in remitted schizophrenics. An ocular reaction time task that schizophrenic perform well.

Twenty-four schizophrenic outpatients in remission were compared with 21 medical outpatient controls on tasks designed to evaluate smooth pursuit of different frequency sinusoidal targets, saccadic eye tracking, and performance on psychomotor analogues of these tasks that require eye-hand coordination. The schizophrenics demonstrated impaired performance on all the smooth-pursuit and psychomotor tracking tasks. However, the oculomotor reaction times of schizophrenics during the saccadic eye-tracking tasks were equal to those of controls. This dissociation of smooth-pursuit and saccadic performance indicates that smooth-pursuit dysfunction cannot be attributed to a lack of motivation, simple inattention, or oculomotor control mechanisms for which the pursuit and saccadic systems share a common anatomy. The saccadic eye-tracking task is quite similar to a variable-foreperiod simple reaction-time task. That schizophrenics produce normal response latencies on this task raises important questions about the nature of the reaction-time deficit in schizophrenia.

Attention↗
PubMed1980

Prevention of relapse in schizophrenia. An evaluation of fluphenazine decanoate.

We tested the role of guaranteed delivery of medication in the prevention of relapse and the enhancement of adjustment in the community in patients with schizophrenia. Two hundred and ninety newly hospitalized patients at four hospitals were randomly assigned to groups receiving either long-acting injectable fluphenazine decanoate or short-acting oral fluphenazine hydrochloride. After discharge and stabilization, patients were treated in the community for up to one year. By the end of the year, 28% of all the patients had relapsed. Contrary to hypothesis, differences between the two treatment groups in relapse percentages were not significant. Furthermore, there were no differences between the treatment groups as to development of affective symptomatology or social adjustment. Patients who rated themselves as having more symptom distress at the start of the community-maintenance phase of the study relapsed much earlier while receiving fluphenazine decanoate rather than fluphenazine hydrochloride. The results suggest that compliance is not an important determinant of relapse among newly discharged schizophrenic patients.

Adult↗
PubMed1980

Catecholamine-sensitive guanylate cyclase from human caudate nucleus.

Partial purification of soluble guanylate cyclase on DEAE-Sephacel yields two separate peaks of guanylate cyclase activity. After 10-fold purification of the soluble enzyme, guanylate cyclase is markedly inhibited by micromolar concentrations of dopamine (I50 = 0.2 microM). Dopamine inhibition is observed whether the reaction is conducted with Mn2+ or with Mg2+, under atmosphere or N2(g), and using enzyme from either peak from the DEAE-Sephacel column. Other catecholamines also inhibit partially purified guanylate cyclase with an order of potency at 1 microM of: dopamine = L-DOPA > norepinephrine = isoproterenol = adrenochrome > epinephrine. The structural requirements for inhibition are two free hydroxyl groups on the phenyl ring and an ethylamine side chain. Dopamine also inhibits the Triton X-100-solubilized microsomal guanylate cyclase after partial purification on DEAE-Sephacel. Neither chlorpromazine, propranolol, nor phentolamine at 20 microM effectively block the dopamine inhibition of partially purified soluble guanylate cyclase. Micromolar concentrations of the reducing agents dithiothreitol and glutathione also inhibit partially purified guanylate cyclase, but unlike these agents, catecholamines can inhibit whether added in the reduced or the oxidized forms. Inhibition of enzyme activity by micromolar concentrations of dopamine, adrenochrome, or dithiothreitol is rapidly reversed by dilution and the dopamine inhibition is competitive with MgGTP. Inhibition does not appear to involve covalent binding or to result from the ability of catecholamines to reduce the concentrations of oxygen or free radicals in solution.

Adrenochrome↗
PubMed1980

Long-term maintenance lithium therapy and possible irreversible renal damage.

This article reviews the literature regarding structural damage and functional disturbances of the kidneys due to long-term maintenance lithium therapy. The correlation between structural changes and functional disturbances of the kidneys is examined. The prognostic implications of lithium-induced nephropathy are discussed, especially in regard to the possible development of chronic renal failure. Recommendations are made to provide maximum benefits of lithium therapy and to minimize accompanying risks of renal side effects.

Acute Kidney Injury↗
PubMed1980

Mania misdiagnosed as schizophrenia.

The charts of 50 patients diagnosed manic on an index admission were reviewed for a previous diagnosis of schizophrenia. Fifty-six per cent of the patients previously ill had been previously misdiagnosed as schizophrenic. During these "schizophrenic" admissions, patients demonstrated a preponderance of affective (manic) symptoms. Irritability was noted much more commonly than euphoria during these admissions. This coupled with the high rate of psychotic symptoms (78%) during the "schizophrenic" admission were likely important reasons for misdiagnosis.

Adult↗
PubMed1979

Physician marriages.

A questionnaire study of physicians' ratings of various aspects of their marriage, was sent to 100 randomly selected physicians in Ramsey County (St. Paul, Minnesota). Eighty per cent of the sample responded. All 80 had been married at least once. There were fewer divorces reported compared with the general population. The group of 80 rated their marriages above average. Spouses who were considered extroverted correlated very significantly with a good marriage rating. The educational level of the spouse did not correlate with the marriage rating. Working long hours was not associated with poor marriage ratings or divorce. No significant relationship was revealed in examining the study variables for grouped medical specialties.

Adult↗
PubMed1977

Depressive subtypes, blood pressure changes and response to treatment.

Blood pressure changes during treatment with an intravenous tricyclic (chlorimipramine) were systematically assessed on twenty depressed patients diagnosed as primary or secondary affective disorders according to research diagnostic criteria. Patients with primary affective disorder showed a significantly greater decline in systolic blood pressure during this treatment than patients with secondary affective disorder. The decline in the blood pressure paralleled clinical improvement. Differential changes in blood pressure appear to be one more instance of constitutional differences for depressive subtypes, and may prove to be practical and reliable predictors of treatment response to tricyclic antidepressants.

Adult↗