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Biomedical subjects

R J Mathew

Publications and source records attributed to R J Mathew.

At least 19 recordsLinked to original sources
PubMed1999

Regional cerebral blood flow and depersonalization after tetrahydrocannabinol administration.

OBJECTIVE: The aim of this study was to examine the relationship between depersonalization induced by tetrahydrocannabinol (THC), and regional brain activation. METHOD: Cerebral blood flow (CBF) was measured by means of positron emission tomography (PET) in 59 normal right-handed volunteers before and following intravenous infusions of THC. RESULTS: After THC, CBF showed a global increase which was more marked in the right hemisphere, frontal lobes and anterior cingulate. CONCLUSION: Regression analyses showed positive correlations between the right frontal and anterior cingulate and depersonalization.

Adult↗
PubMed1998

Cerebellar activity and disturbed time sense after THC.

Because marijuana continues to be the most commonly used illicit drug, its effects on the brain function are of major interest. We utilized positron emission tomography (PET) and magnetic resonance imaging (MRI) to study the effects of delta-9-tetrahydrocannabinol (THC) infusion on brain blood flow and its behavioral correlates in 46 volunteers. Consistent with previous reports, there was a significant increase in cortical and cerebellar blood flow following THC, but not all subjects showed this effect. Those who showed a decrease in cerebellar CBF also had a significant alteration in time sense. The relationship between decreased cerebellar flow and impaired time sense is of interest because the cerebellum has been linked to an internal timing system.

Adult↗
PubMed1997

Intracranial and extracranial blood flow during acute anxiety.

While large numbers of studies are available on anxiety and cerebral blood flow (CBF), little is known about their relationship to extracranial (forehead) flow. The participants were 24 generalized anxiety disorder (GAD) patients and 26 normal volunteers. A randomized, between groups, repeated measures design was used to evaluate changes in cerebral blood flow. Measurements of CBF, forehead skin perfusion and ratings of anxiety and physiologic indices were made under resting conditions and during anxiety induction with epinephrine or saline infusions, given under double-blind conditions while subjects inhaled room air or 5% CO2. These subjects were divided into three groups; those with decreased anxiety, those with mild anxiety, and those with more severe anxiety increase. Subjects with severe anxiety showed least hypercarbic CBF increase (indicating cerebral vasoconstriction) and maximal increase in forehead skin perfusion. Those with minimal anxiety had most hypercarbic cerebral vasodilation and least increase in forehead skin perfusion. Forehead skin perfusion correlated positively with anxiety levels, and negatively with hypercarbic cerebral vasodilation. In animals, sympathetic activation limits hypercapnic cerebral vasodilation. Thus, the restricted hypercapnic cerebral vasodilation during severe anxiety may be mediated through cervical sympathetic fibers which innervate cerebral vessels.

Acute Disease↗
PubMed1997

Effect of nitrous oxide on cerebral blood velocity while reclining and standing.

Cerebral blood velocity (CBV) (measured with transcranial Doppler, TCD) and other physiological and rating scale indices were measured before, during, and after inhaling a mixture of 40% nitrous oxide/oxygen and 40% nitrogen/oxygen, given during two separate visits in 7 normal male volunteers. During nitrous oxide/oxygen but not nitrogen/oxygen inhalation, CBV and euphoria increased significantly with minimal changes in other physiological indices except an increase in pulse rate after nitrous oxide/oxygen. In another 7 male volunteers, similar measurements were obtained while lying down and standing up during nitrous oxide/oxygen mixture and nitrogen/oxygen mixture inhalations, given during two separate visits. Nitrous oxide/oxygen inhalation produced significant CBV increase, which showed nonsignificant decrease of no clinical significance during standing up. There were no significant postural changes in blood pressure. Standing up during nitrous oxide/oxygen inhalation was associated with significant though mild dizziness.

Administration, Inhalation↗
PubMed1997

Cerebral vasodilation and vasoconstriction associated with acute anxiety.

A randomized, between-groups, repeated measures design was used to evaluate changes in cerebral blood flow (CBF), rating scales, and physiologic indices under resting conditions, during 5% CO2 inhalation in combination with epinephrine or saline infusions, in generalized anxiety disorder patients and controls. Subjects were divided into those with decreased anxiety and mild and more severe anxiety increase. The first group was found to have most pronounced CBF increase during CO2 inhalation, with the second group showing less marked increase, and the last group the least increase. In animals, sympathetic activation limits hypercapnic cerebral vasodilation. Thus, the restricted hypercapnic cerebral vasodilation during severe anxiety may be mediated through cervical sympathetic fibers, which innervate cerebral vessels.

Acute Disease↗
PubMed1997

Marijuana intoxication and brain activation in marijuana smokers.

OBJECTIVE AND METHOD: The acute effects of delta9 tetrahydrocannabinol (THC) on cerebral blood flow (CBF) were studied in human subjects. Regional CBF was measured with 15O-water and Positron Emission Tomography (PET) in 32 volunteers with a history of exposure to marijuana. Scans were performed before and after intravenous (I.V.) infusion of either of two doses of THC or a placebo, given under double blind conditions. RESULTS: THC but not placebo increased CBF especially in the frontal regions bilaterally, insula and cingulate gyrus and sub-cortical regions with somewhat greater effects in the right hemisphere. While most regions showed significant change at 60 minutes for the lower dose group, the higher dose group had significant change at 30 and 60 minutes. There was a highly significant change in the anterior/posterior ratio for the two THC groups reflecting minimal change in occipital flow but significant increases in frontal flow. Self ratings of THC intoxication showed significant effects, and regression analysis indicated it correlated most markedly with the right frontal region. CONCLUSION: Behavioral manifestations of marijuana intoxication may be associated with increased functional activity of the brain especially the frontal cortex, insula and cingulate gyrus.

Adult↗
PubMed1996

Acute changes in cranial blood flow after cocaine hydrochloride.

Cerebral blood flow (CBF) was measured with the 133Xenon inhalation technique and forehead skin flow with laser Doppler, before and twice after 0.3 milligram/kilogram of cocaine hydrochloride and a placebo given intravenously to six cocaine abusers, during two visits, separated by a minimum of one week. After cocaine, subjects showed significant increases in intoxication and tension. Systolic blood pressure and pulse rate also increased significantly after the drug but not after the placebo. CBF, with and without correction for end-tidal CO2, showed increases in left and right hemisphere after cocaine. The CBF increase was maximal in frontal, central and parietal regions. CBF changes correlated only with changes in a rated level of intoxication. Forehead skin flow did not change after cocaine or placebo. In habitual cocaine abusers, 0.3 mg/kg of cocaine, given intravenously produced increased CBF and no changes in forehead skin flow.

Adult↗
PubMed1995

Measurement of materialism and spiritualism in substance abuse research.

OBJECTIVE: A modified version of an instrument called the Mathew Materialism-Spiritualism Scale (MMSS), originally developed in India, was evaluated for possible use in substance abuse research in the U.S. METHOD: The scale was administered to 62 individuals recovering from substance use, 20 clergy people and 61 general controls. RESULTS: Test-retest reliability for the MMSS was verified by administering it to 18 control subjects on two separate occasions, 7 days apart. The Pearson correlation for the MMSS total scores was 0.83 (p < .0001). Internal consistency was examined with Cronbach's alpha in the entire sample of 143 subjects; the result for the total score was .93. Factor analysis showed a factor structure compatible with the subscales proposed by the developer. Women, in general, obtained higher spirituality scores. Members of the recovering group obtained significantly higher scores on "character" and "mysticism" than the general controls. When general controls were divided into MAST positive and MAST negative individuals, the MAST positive group obtained lower scores than the recovering group for "God," "mysticism" and "character." MAST negative individuals had lower scores on "mysticism" than the recovering group. Christians had higher scores on "God" and "religion" subscales than did nonChristians and agnostics. CONCLUSIONS: The results of this study need confirmation using an improved methodology and larger sample sizes. However, they suggest that the scale may be useful for the study of spirituality in the U.S.

Adult↗
PubMed1994

Effects of marijuana on performance of a computerized cognitive-neuromotor test battery.

To evaluate the sensitivity of a computerized cognitive-neuromotor test battery in assessing the effects of marijuana (delta-9-tetrahydrocannabinol [THC]), we conducted a study of 10 healthy male volunteers who were experienced marijuana smokers. After extensive training on the performance tasks, each subject was tested on three separate days after smoking a cigarette containing either 1.75% THC, 3.55% THC, or placebo according to a randomized double-blind repeated measures design. Testing was carried out before smoking and 30, 90, and 150 minutes after smoking the cigarette. Of the five tasks employed, the digit-symbol substitution test with memory and the reaction time task were the measures most sensitive to effects of marijuana. We examined the usefulness of the coefficient of variation and effect size as indices of sensitivity to be used across different types of tasks.

Adult↗
PubMed1993

Depersonalization after marijuana smoking.

Depersonalization and other behavioral and physiological indices were monitored before and after the administration of high- and low-potency marijuana cigarettes and a placebo cigarette in 35 physically and mentally healthy normal volunteers. The cigarettes were administered under double-blind conditions during three visits to the laboratory separated by a minimum of 1 week. Marijuana smoking, but not placebo smoking, was associated with significant depersonalization that was maximal 30 min after smoking the high-potency cigarettes. Other behavioral changes induced by marijuana included disintegration of time sense, sensation of "high," increased state anxiety, tension, anger, and confusion. Respiration, pulse rate, and systolic blood pressure also increased after marijuana smoking. Multiple regression identified temporal disintegration as the most significant predictor of depersonalization.

Adult↗
PubMed1993

Acute changes in cerebral blood flow after smoking marijuana.

In experienced marijuana smokers, marijuana smoking was accompanied by a significant bilateral increase in cerebral blood flow (CBF) especially in the frontal regions and cerebral blood velocity. The post-marijuana CBF increase could not be explained on the basis on changes in general circulation or respiration. Similarly, the CBF increase was unrelated to plasma levels of tetrahydrocannabinol and extracranial circulation. Behavioral changes showed significant correlations with CBF. CBF and brain function are closely coupled and therefore it seemed highly likely that CBF changes after marijuana were closely related to its effect on mood and behavior.

Adult↗
PubMed1993

Psychiatric disorders in adult children of alcoholics: data from the Epidemiologic Catchment Area project.

OBJECTIVE: The authors examined differences in the prevalence of psychiatric disorders in individuals who did or did not have alcoholic parents. METHOD: They used data from the National Institute of Mental Health Epidemiologic Catchment Area project, specifically from the Piedmont of North Carolina. Prevalence of psychiatric disorders was estimated in 408 ECA participants who reported problem drinking in their mother, their father, or both and in 1,477 age- and sex-matched subjects who did not report having alcoholic parents. RESULTS: The adult children of alcoholics showed significantly higher current (6-month) prevalence rates of simple phobia and agoraphobia and lifetime rates of dysthymia, generalized anxiety disorder, panic disorder, simple phobia, and agoraphobia. Adult children of alcoholics also had significantly more antisocial symptoms. Male children of alcoholics had higher rates of alcohol and drug abuse and reported more antisocial symptoms than did female children of alcoholics. Male children of alcoholics had a significantly higher rate of lifetime diagnoses of alcohol and drug abuse than men who were not children of alcoholics. More female children of alcoholics had generalized anxiety disorder than women who were not children of alcoholics. Both male and female children of alcoholics had significantly more antisocial symptoms than their matched comparison subjects. Sons of alcoholic fathers had a higher rate of substance abuse and more antisocial symptoms than did daughters of alcoholic fathers. Daughters of alcoholic fathers had a higher rate of generalized anxiety disorder. CONCLUSIONS: These data on adult children of alcoholics in a large community sample add to a literature based mainly on descriptive material or studies of smaller samples.

Agoraphobia↗