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Biomedical subjects

R J Mathew

Publications and source records attributed to R J Mathew.

At least 55 records · Page 3Linked to original sources
PubMed1989

Responses to hypercarbia induced by acetazolamide in panic disorder patients.

CO2 inhalation has been reported to induce panic attacks in panic disorder patients. State anxiety, somatic symptoms of anxiety, physiological changes, and cerebral blood flow (CBF) were monitored in panic disorder patients before and after intravenous injections of 1 g of acetazolamide (13 patients) and saline (10 patients), given under double-blind conditions. In spite of significant hypercarbia, as evidenced by increased CBF in the former group, only one subject reported panic and even that attack did not meet DSM-III-R criteria. There was only one significant difference between the drug and placebo groups; the acetazolamide group experienced significantly more dizziness.

Acetazolamide↗
PubMed1989

Regional cerebral blood flow correlates of a dichotic listening task.

This investigation was designed to test the hypothesis that ear advantage on a dichotic listening (DL) task of pitch discrimination reflects asymmetries in the metabolic activities of the temporal lobes. Fourteen normal subjects, with either a left-ear advantage (LEA) (n = 9) or a right-ear advantage (REA) (n = 5) on the DL task, underwent measurements of regional cerebral blood flow (rCBF) during a resting baseline condition and during performance on the DL task. For both groups, the DL task was associated with selective and significant increases in rCBF to the contralateral posterior temporal lobe. Our finding of selective rCBF activation with dichotic stimulation may have potential implications for an understanding of the functional organization of the cerebral hemispheres.

Acoustic Stimulation↗
PubMed1988

Abnormal resting regional cerebral blood flow patterns and their correlates in schizophrenia.

Regional cerebral blood flow (CBF) was measured under resting conditions in 108 right-handed schizophrenic inpatients and a matched group of normal controls with the xenon 133 inhalation technique. Forty-six patients were free of all medication for two weeks. There were no significant differences in CBF to the two hemispheres. The patients showed a comparatively reduced anteroposterior (AP) gradient for CBF. Though there were no differences in frontal flow, the patients had higher flow to several postcentral brain regions, bilaterally. Cerebral blood flow in the patients correlated inversely with age and positively with carbon dioxide level. Women had higher flow than men. Duration of the illness was the only significant predictor of the reduced AP gradient in patients. Higher left temporal and right parietal flow were found to be the best discriminators between patients and controls. Mean hemispheric flow to both hemispheres and several brain regions correlated with the total score and the item, unusual thought content, of the Brief Psychiatric Rating Scale. There were no differences in regional CBF between medicated and unmedicated patients.

Adult↗
PubMed1988

Cerebral blood flow changes induced by CO2 in anxiety.

Cerebral blood flow (CBF) was measured twice with the 133Xenon inhalation technique, under resting conditions and during 5% CO2 inhalation, in 13 patients with generalized anxiety disorder and a group of normal volunteers of comparable age and sex distribution. CO2 inhalation was associated with similar increases in end-tidal CO2 (PECO2) and CBF. Neither group showed statistically significant increases in state anxiety. However, when subjects (both patients and controls) who became anxious during CO2 inhalation were compared with those who did not, on associated CBF changes, significant differences emerged. The former showed less marked CBF increase as compared to the latter in the absence of any significant differences between the two groups on PECO2 during the second measurement. Changes in state anxiety and CBF showed a statistically significant inverse correlation for the entire group.

Adult↗
PubMed1986

Caffeine-induced cerebral blood flow changes in schizophrenia.

Cerebral blood flow (CBF) measurements and mental status examinations were performed before and 30 min after oral administration of 250 mg of caffeine or a placebo given under double-blind conditions, in two groups of patients with schizophrenia. Caffeine produced significant CBF reductions but no changes in the patient's clinical condition.

Adult↗
PubMed1986

Determinants of resting regional cerebral blood flow in normal subjects.

Study of brain function via cerebral blood flow and metabolism measurements is believed to be of considerable significance in psychiatry. The present study examined the factors that determined patterns of regional cerebral blood flow (CBF) in 140 physically and mentally healthy, drug-free volunteers under resting conditions. Age, sex, and end-tidal CO2 levels were identified as the most powerful determinants of CBF, in that order. Age-related CBF reduction was found to be most marked in the frontal region. Women had higher CBF than men, and the difference was most obvious in the frontal region. The correlations between CO2 and CBF showed less striking, but significant, regional variations. Hematocrit was found to exert only minimal influence in the control of resting CBF.

Adult↗
PubMed1986

Hematocrit and anxiety.

Stress is believed to increase hematocrit. Groups of patients with generalized anxiety disorders and normal volunteers matched on age and sex were compared on resting levels of state anxiety, trait anxiety, depression, pulse rate, blood pressure and hematocrit. There were no differences between the patients and controls on hematocrit, although the former showed significantly higher state anxiety, trait anxiety and depression. The measurements were repeated in the anxious patients after one-half of the subjects received an intravenous infusion of epinephrine and the other half saline. Epinephrine was associated with significant increases in state anxiety, pulse and systolic blood pressure, but not with any hematocrit or plasma volume changes.

Adult↗
PubMed1985

Dextroamphetamine-induced changes in regional cerebral blood flow.

Regional cerebral blood flow (CBF), blood pressure, pulse rate, respiratory rate, end-tidal carbon dioxide and mood states were measured before and after IV injections of 15 mg dextroamphetamine sulfate or saline in 22 physically and mentally healthy normal volunteers. Amphetamine administration was associated with significant increases in systolic blood pressure and vigor and decrease in end-tidal carbon dioxide. There were no significant differences between the amphetamine and saline groups on CBF changes. However, there was a non-significant trend towards a post-amphetamine CBF reduction, even after the flow values were corrected for the acute changes in CO2.

Adult↗
PubMed1985

The effect of nonsedating doses of diazepam on regional cerebral blood flow.

Drugs like diazepam induce tranquilization in small doses and sedation in larger quantities. Regional cerebral blood flow (rCBF) was measured before and 5 min after the intravenous administration of nonsedating doses of diazepam or placebo (given on a double-blind basis) to 20 right-handed volunteers. Subjects who received diazepam showed marked right hemispheric rCBF decreases, especially in the frontal lobe, whereas controls did not show significant differences between the two sets of values. None of the subjects became sleepy during the experiment.

Adult↗
PubMed1985

Regional cerebral blood flow in dialysis encephalopathy and primary degenerative dementia.

Regional cerebral blood flow (CBF) was measured in patients with dialysis encephalopathy, primary degenerative dementia, dialysis patients with no central nervous system (CNS) complications, and normal controls. Both groups of dialysis patients (with and without CNS complications) demonstrated higher CBF values, and the dementia patients, lower CBF values than the controls. The dialysis patients had lower hematocrit, which correlated inversely with the cerebral blood flow. No such correlations were present in normals and patients with primary degenerative dementia. The dialysis patients and controls obtained similar CBF when the flow values were adjusted for the differences in hematocrit.

Aged↗