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Biomedical subjects

M S George

Publications and source records attributed to M S George.

At least 19 recordsLinked to original sources
PubMed1992

Demonstration of human motor cortex activation using SPECT.

Recent advances in single photon emission computed tomography (SPECT) have allowed improved image resolution with lower doses of labelled tracer. Capitalizing on these improvements, the authors have developed a new SPECT protocol for imaging neuronal activation. We outline this technique and describe how it can demonstrate increased human motor cortex activity in normal subjects performing a motor task. The ability to accurately demonstrate neuronal activation with SPECT using this method may have important scientific and clinical implications.

Adult↗
PubMed1992

Elevated frontal cerebral blood flow in Gilles de la Tourette syndrome: a 99Tcm-HMPAO SPECT study.

Case reports, numerous brain imaging studies, and certain disease states suggest that the orbital frontal cortex and the striatum are dysfunctional in obsessive-compulsive disorder (OCD). Interest has also grown recently concerning the genetic, neuroanatomic, and clinical links between OCD, chronic motor tics, and Gilles de la Tourette Syndrome (GTS). To test the hypothesis of possible orbito-frontal/basal ganglia dysfunction in GTS, similar to OCD, we studied 20 unmedicated GTS subjects, 10 of whom also had comorbid OCD (GTS/OCD), and 8 control subjects. The subjects were examined with high-resolution single photon emission computed tomography (SPECT) and the labeled regional cerebral blood flow (rCBF) ligand technetium-99m-d,l-hexamethyl-propylene amine oxime (99Tcm-HMPAO). As a group, GTS subjects showed significantly elevated right frontal/visual cortex activity (mean = 0.879, SD = 0.107) compared with control subjects (mean = 0.798, SD = 0.049). A subanalysis comparing simple GTS versus GTS with comorbid OCD failed to reveal significant differences in regional flow.

Adult↗
PubMed1992

Cerebral blood flow abnormalities in adults with infantile autism.

Structural brain abnormalities have recently been discovered using magnetic resonance imaging in infantile autism, a neurodevelopmental disorder of unknown etiology. However, functional neuroimaging studies in autism using positron emission tomography have had conflicting results and have not explained how the known structural brain abnormalities in autism act in a functioning brain to produce autistic behavior. Using a new technology, high-resolution brain single photon emission tomography, we studied and scanned four young adults with infantile autism and four age-matched controls using the labeled ligand 99mTc-D,L-hexamethyl-propylene amine oxime (99mTc-HMPAO). Total brain perfusion was significantly decreased in autism subjects (range, 58% to 72% of controls, p less than or equal to .02). In addition to the globally decreased perfusion, the autism group also had regionally decreased flow in the right lateral temporal and right, left, and midfrontal lobes compared with controls (p less than or equal to .02, Mann-Whitney t-test).

Adult↗
PubMed1992

Effect of vigabatrin on striatal dopamine receptors: evidence in humans for interactions of GABA and dopamine systems.

Vigabatrin is a specific gamma-aminobutyric acid transaminase inhibitor. The clinical use of this drug in the treatment of epilepsy has been sporadically linked to the development of psychosis. Using 123I-IBZM, a specific dopamine D2 receptor ligand and single photon emission tomography (SPET), one month of treatment with vigabatrin was associated with a decrease in specific binding of 123I-IBZM to D2 receptors in the left hemisphere basal ganglia. This change may provide one explanation for the development of psychosis in vulnerable patients.

Adolescent↗
PubMed1992

The changing 19th-century view of epilepsy as reflected in the West Riding Lunatic Asylum Medical Reports, 1871-1876, vols 1-6.

The West Riding Lunatic Asylum Medical Reports (WRLAMR) were published from 1871 to 1876. Organized by Sir James Crichton-Browne at a little-known mental asylum in northern England, the WRLAMR contains many historically important works in neurology by such landmark figures as Sir David Ferrier and John Hughlings Jackson. The writings on epilepsy in the WRLAMR are particularly important and reveal the 19th-century shift in understanding the etiology of seizures.

England↗
PubMed1991

Speed of onset of action of the newer antidepressants--fluoxetine and bupropion.

The authors review 24 double-blind placebo-controlled studies comparing fluoxetine or bupropion against previously available antidepressants, to assess where there is evidence for a difference in the speed of onset of antidepressant action. Critical comparison of the studies showed no difference in speed of onset of action between these newer agents and conventional antidepressants.

Antidepressive Agents↗
PubMed1991

Obsessive-compulsive disorder.

Within the past decade the field of psychiatry has rediscovered the neuropsychiatric syndrome of obsessive-compulsive disorder (OCD). Although excellently described over 150 years ago, for many years OCD was thought to be rare, untreatable, and to arise from hidden psychodynamic conflicts. All of these earlier ideas now appear to be wrong. Occurring in approximately 2% of adults, OCD consists of recurrent intrusive thoughts (obsessions) or senseless repetitive actions (compulsions). Although the aetiology of OCD remains unclear, recent neuro-imaging studies implicate the basal ganglia and frontal cortex as crucial structures in the pathogenesis of OCD. Genetic studies demonstrate a clear genetic component to OCD and an interesting link with chronic motor tics and the Gilles de la Tourette Syndrome. Although a true cure for the disorder remains elusive, most OCD symptoms respond well to treatment with 5HT reuptake inhibitors. The phenomenology and aetiology of OCD will be reviewed, with particular emphasis placed on the proper pharmacological treatment of this sometimes crippling disorder.

Clomipramine↗
PubMed1990

A study of the seasonal variation of migraine.

Available evidence supports the contention that migraine involves a disturbance in serotonin function. Several parameters of serotonin function in humans have been found to vary seasonally and may underlie the seasonal fluctuations observed in many clinical neuropsychiatric phenomena that are thought to involve serotonin dysfunction. We therefore postulated that migraine headaches might also vary seasonally and examined the admissions to our hospital over a 20-year period with a primary diagnosis of migraine. Peak admissions were found to occur most frequently in the spring for females in comparison to males (p less than or equal to 0.04, chi-square). The implications of these findings are discussed.

Chi-Square Distribution↗
PubMed1990

Establishing brain death in South Carolina: a clinician's guide.

With recent technological and medical advances, basic cardiopulmonary function can now be prolonged in many patients. Concurrently, organ transplantations have become more common and interest in living wills has increased. As a result, the South Carolina physician is increasingly obligated to determine whether a patient receiving cardiopulmonary support is dead due to irreversible cessation of brain function (ICBF) (brain dead). Here we review the bedside clinical valuation of brain death (ICBF), the adjunctive use of the EEG and other tests, and the South Carolina laws pertaining to this complex decision.

Brain Death↗
PubMed1989

Abnormalities of the septum pellucidum in schizophrenia.

The authors present two cases of schizophrenia in young males who have malformations of the septum pellucidum, a thin sheet of cells and fibers located in the midline of the brain that separates the lateral ventricles. These cases are discussed in the context of newly proposed neurodevelopmental models of schizophrenia.

Adult↗