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Biomedical subjects

S K Teoh

Publications and source records attributed to S K Teoh.

At least 37 records · Page 2Linked to original sources
PubMed1992

Quantitative magnetic resonance imaging in heroin- and cocaine-dependent men: a preliminary study.

Quantitative magnetic resonance imaging (MRI) of the brain was performed in nine drug-dependent men with a primary diagnosis of opioid and/or cocaine dependence, and 10 age-matched, non-drug-dependent controls. Individuals were screened for the presence of gross cerebral abnormalities before T1 and T2 analyses. Regional T1 and T2 times were calculated on a single 5-mm thick axial slice positioned just below the caudal margin of the lateral ventricles, passing through the caudate and putamen. A voxel of interest (VOI) cursor was placed bilaterally within the putamen, caudate, frontal gray matter, frontal white matter, or posterior white matter. T1 and T2 values were determined for each VOI using an iterative chi 2 minimization program. T1 and T2 relaxation times did not differ significantly between the subject groups in any brain region studied. These results suggest that T1 and T2 relaxation times may not identify microstructural central nervous system changes resulting from chronic opiate and cocaine abuse.

Adult↗
PubMed1992

Hyperprolactinemia and macrocytosis in women with alcohol and polysubstance dependence.

Chronic alcoholism and drug abuse are often associated in women with derangements of reproductive function such as amenorrhea, anovulation, luteal phase dysfunction and early menopause. Endocrine profiles were studied of the first 18 women (aged 17-58) admitted consecutively to a Massachusetts hospital for treatment of alcohol/polysubstance dependence under civil commitment. Twelve women were diagnosed as alcohol dependent according to criteria established in DSM-III-R. Their daily alcohol consumption ranged from 42-324 grams. Six women were diagnosed as polysubstance dependent. In addition to alcohol (84-831 g/day), cocaine was the most frequently abused drug followed by tranquilizers, marijuana and opiates. Over 60% of alcohol-dependent women of reproductive age had either hyperprolactinemia or macrocytosis (increased mean corpuscular volume, MCV), or both. Over 60% of the polysubstance-dependent women of reproductive age had either hyperprolactinemia or increased MCV. Over 80% of alcohol-dependent women of postmenopausal age had either hyperprolactinemia or increased MCV, or both. We conclude that evaluation of plasma prolactin levels and MCV may be useful as biological state markers for alcoholism and polysubstance abuse in women.

Adolescent↗
PubMed1992

Buprenorphine attenuates the effects of cocaine on adrenocorticotropin (ACTH) secretion and mood states in man.

Adrenocorticotropin (ACTH) levels in plasma increased rapidly to 105% above baseline within 5 minutes after intravenous injection of cocaine (30 mg) in cocaine-dependent men. The time course of ACTH stimulation paralleled increases in plasma cocaine levels and self-reports of salient drug effects on mood states and did not occur after placebo administration. An opioid mixed agonist-antagonist, buprenorphine (4 mg/day sublingually), suppressed the acute cocaine-induced stimulation of both ACTH and euphoria. Buprenorphine's suppression of postcocaine ACTH and euphoria were not related to differences in plasma cocaine levels or cocaine-induced alterations of cardiovascular function.

Adrenocorticotropic Hormone↗
PubMed1992

Acute effects of cocaine on plasma adrenocorticotropic hormone, luteinizing hormone and prolactin levels in cocaine-dependent men.

Acute cocaine administration alters secretion of anterior pituitary hormones in experimental animals, and cocaine abuse may compromise neuroendocrine function in humans. The goal of this study was to examine cocaine's acute effects on neuroendocrine hormones in cocaine-dependent men. Plasma adrenocorticotropic hormone (ACTH), luteinizing hormone and prolactin levels were measured in 18 men before and after i.v. administration of cocaine (30 mg) or placebo. Each subject served as his own control during the i.v. placebo and cocaine administration conditions. Plasma cocaine levels peaked at 260 ng/ml within 5 min after the i.v. injection. Plasma ACTH levels increased significantly above base-line levels at 5, 15, 30 (P < .01) and 45 min (P < .05) after i.v. cocaine. Plasma luteinizing hormone levels increased significantly above base-line levels at 5 (P < .05) and at 15 min (P < .01) after i.v. cocaine. No changes in plasma ACTH or luteinizing hormone levels were found after i.v. placebo injection. Plasma prolactin levels decreased significantly at 30, 45, 60, 90 and 120 min (P < .01) after both i.v. cocaine and placebo administration. Cocaine-induced increases in plasma ACTH levels may be due to its effects on dopaminergic systems which modulate corticotropin-releasing factor release in brain.

Adrenocorticotropic Hormone↗
PubMed1992

A comparison of brain perfusion SPECT in cocaine abuse and AIDS dementia complex.

Intravenous drug use is a major risk factor for HIV-1 infection. Since both AIDS dementia complex (ADC) and cocaine have been associated with abnormal brain perfusion imaging, we compared the scintigraphic patterns of ADC patients and cocaine polydrug users with normal control subjects using 99mTc-HMPAO SPECT. We found a high incidence of cortical defects in both ADC (100%) and cocaine-dependent (90%) subjects. In the cocaine and ADC patients, cortical defects were most frequent in the frontal, temporal and parietal lobes and occurred with similar frequency in the two populations. In both groups, the number of cortical defects per subject was higher than normal subjects (10.0 +/- 5.0 for ADC, 10.1 +/- 5.2 for cocaine and 0.7 +/- 1.5 for normal), background activity was high (a 65% and 60% incidence for ADC and cocaine, respectively), and basal ganglia involvement was frequent (40% and 65% for ADC and cocaine). We conclude that the brain perfusion pattern, while a sensitive indicator of ADC, cannot be distinguished from chronic cocaine polydrug use and caution should therefore be applied before entertaining a specific diagnosis.

AIDS Dementia Complex↗
PubMed1991

Brain perfusion is abnormal in cocaine-dependent polydrug users: a study using technetium-99m-HMPAO and ASPECT.

Cocaine abuse is widespread and has been associated with serious neurovascular complications. We studied a group of cocaine-dependent polydrug users with 99mTc-HMPAO and high-resolution SPECT and compared their perfusion pattern to cerebral perfusion in a group of older control subjects. Sixteen of 18 cocaine-dependent polydrug users had abnormal perfusion characterized primarily as small focal defects involving inferoparietal, temporal, and anterofrontal cortex and basal ganglia. Psychometric testing was abnormal in all 18 cocaine-dependent subjects. No relation was found between the severity of SPECT abnormalities and mode of administration or frequency or length of cocaine use. All 15 older normal subjects had normal cerebral perfusion. While the focal perfusion abnormalities to the cortex and basal ganglia could be explained by the profound vasoconstrictor effects of cocaine, the combinational use of multiple substances including cannabis and alcohol may play a contributory role. This study documents the high incidence of functional brain abnormalities in cocaine-dependent chronic polydrug users without corresponding abnormalities on imaging studies of cerebral anatomy and morphology.

Adult↗
PubMed1990

Characteristics of women receiving mandated treatment for alcohol or polysubstance dependence in Massachusetts.

Characteristics of the first 20 women consecutively admitted for treatment for alcohol or polysubstance dependence following civil commitment by Massachusetts courts were studied. Women were diagnosed as either alcohol dependent (n = 12) or polysubstance dependent (n = 8). Alcohol dependent women were older at initial alcohol use, onset of regular alcoholic use, first treatment admission, and at this admission. For the group as a whole 75% had completed high school; 50% were divorced and 35% were supported by public assistance. Seventy-five percent had a family history of alcoholism. This sample of women who received court-ordered alcohol and polysubstance dependence treatment had multiple social, psychological, legal and health problems.

Adolescent↗
PubMed1990

Alcohol effects on hCG-stimulated gonadal hormones in women.

Chronic alcohol abuse is associated with derangements of reproductive function in women. The mechanism of increased risk for alcohol-related abortions and fetal alcohol syndrome is unknown. The goal of this study was to determine if acute alcohol administration affected gonadal steroid hormone levels after administration of human chorionic gonadotropin (hCG) to normal healthy women. hCG was used to simulate the hormonal milieu during the first trimester of pregnancy. Ten women were studied during the mid-luteal phase (between days 17 and 23) of their menstrual cycle. Plasma estradiol, progesterone and prolactin were measured before and after simultaneous administration of 5000 I.U. of hCG (Profasi) and alcohol or placebo solution under double-blind conditions. There was a significant increase in plasma estradiol (P less than .001) and prolactin levels (P less than .01) after hCG and alcohol administration but not after hCG and placebo administration. Plasma progesterone increased significantly (P less than .001) above base line after hCG and placebo administration but this was not observed after hCG and alcohol administration. Since progesterone is essential for the maintenance of pregnancy, alcohol's attenuation of the expected progesterone response to hCG stimulation could increase the risk of spontaneous abortion. An alcohol-induced increase in estradiol after hCG administration could contribute to risk for fetal dysmorphology during the first trimester of pregnancy.

Administration, Oral↗
PubMed1990

Operant acquisition of alcohol by women.

Alcohol acquisition and use patterns were studied in 26 women on a clinical research ward. Women could earn alcohol (beer, wine or distilled spirits) or 50 for 30 min of performance on a second-order fixed ratio 300 (fixed interval 1 sec: S) schedule of reinforcement. Points earned for money and for alcohol were not interchangeable. A 7-day drug-free base line was followed by 21 days of alcohol availability and a postalcohol drug-free period of 7 days. Heavy, moderate and occasional drinkers differed significantly in the average number of alcohol drinks purchased (P less than .001). Five heavy drinkers purchased an average of 164 (+/- 14) drinks during the study; 12 moderate drinkers purchased an average of 80 (+/- 4) drinks; 9 occasional drinkers purchased an average of 26 (+/- 4) drinks. Individual drinking patterns fluctuated markedly from day-to-day. Daily peak blood alcohol levels (milligrams per deciliter) were significantly correlated with variations in daily drinking patterns in 22 of the 26 subjects (P less than .02-.0001). Computer analysis of daily alcohol consumption patterns (alcohol peak frequency and peak amplitude) showed that moderate drinkers had significantly more peaks in alcohol consumption than occasional drinkers (P less than .05). The average number of drinks constituting each peak was significantly greater for the heavy and moderate drinkers than for the occasional drinkers (P less than .05). The interval between successive peaks in alcohol consumption averaged 4.6 (+/- 0.8) days for the occasional drinkers, 3.2 (+/- 0.2) days for the moderate drinkers and 3.6 (+/- 0.17) days for the heavy drinkers but these differences were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed1989

Naloxone suppresses buprenorphine stimulation of plasma prolactin.

The effects of parenterally-administered buprenorphine and simultaneous injection of naloxone was evaluated in six healthy adult males. Each subject was studied on six occasions, an average of 10 days apart, and received either two simultaneous intramuscular injections of saline, buprenorphine 0.3 mg and saline, or buprenorphine 0.3 mg and 0.6 mg, 0.45 mg, 0.3 mg, or 0.15 mg of naloxone. Simultaneous injection of buprenorphine 0.3 mg and saline resulted in an average increase in plasma prolactin above baseline levels of approximately 10 and 25 ng/ml, 30 and 55 minutes after injection. Buprenorphine-induced stimulation of plasma prolactin levels was statistically significantly greater than basal prolactin values (p less than 0.01). When 0.6 mg of naloxone was simultaneously injected with 0.3 mg buprenorphine, peak plasma prolactin levels were significantly lower (p less than 0.05) than prolactin values after administration of 0.3 mg buprenorphine and saline. Simultaneous injection of 0.45 mg naloxone and 0.3 mg buprenorphine also resulted in a significant attenuation (p less than 0.05) of buprenorphine-stimulated prolactin levels. Injection of 0.3 mg or 0.15 mg of naloxone did not inhibit prolactin stimulation produced by buprenorphine 0.3 mg. These findings demonstrate a dose-effect relationship between naloxone concentration and suppression of the increase in plasma prolactin levels produced by administration of buprenorphine 0.3 mg. As prolactin stimulation occurs shortly after opioid agonist administration and is temporally concordant with the rapid induction of pharmacologic reinforcement associated with opiate abuse, naloxone added to buprenorphine parenteral preparations may reduce the abuse potential of buprenorphine.

Adolescent↗