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Biomedical subjects

H A Ring

Publications and source records attributed to H A Ring.

31 records · Page 2Linked to original sources
PubMed1993

Obsessions in obsessive-compulsive disorder with and without Gilles de la Tourette's syndrome.

OBJECTIVE AND METHOD: Although obsessive-compulsive disorder commonly occurs in many patients with Gilles de la Tourette's syndrome, little is known about the obsessions and compulsions of Tourette's syndrome and whether they differ from those seen in pure obsessive-compulsive disorder. The authors prospectively studied 10 subjects with obsessive-compulsive disorder and 15 subjects with obsessive-compulsive disorder and comorbid Tourette's syndrome by using the Yale-Brown Obsessive Compulsive Scale, the Leyton Obsessional Inventory, and a new questionnaire designed to emphasize the differences in symptoms between these two groups. RESULTS: Subjects with comorbid obsessive-compulsive disorder and Tourette's syndrome had significantly more violent, sexual, and symmetrical obsessions and more touching, blinking, counting, and self-damaging compulsions. The group with obsessive-compulsive disorder alone had more obsessions concerning dirt or germs and more cleaning compulsions. The subjects who had both disorders reported that their compulsions arose spontaneously, whereas the subjects with obsessive-compulsive disorder alone reported that their compulsions were frequently preceded by cognitions. CONCLUSIONS: There are phenomenologic differences between obsessive-compulsive disorder and obsessive-compulsive disorder with comorbid Tourette's syndrome that may reflect differential involvement of neurochemical and neuroanatomic pathways.

Adult↗
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↗
PubMed1991

The use of cerebral activation procedures with single photon emission tomography.

Single photon emission tomography allows the imaging of dynamic brain functioning. The use of cerebral activating procedures within the scan protocol enables investigation of the mechanisms involved in specific brain functions in health and disease. Activation studies involve the comparison of at least two data sets describing brain activity generated in conditions that differ for the specific function in question. When designing an activation study, decisions regarding methodology include: the nature of the activation regime, the tracer-ligand utilized, the SPET instrument and the manner of subsequent data analysis. These issues are discussed in this review, both theoretically and with reference to published studies. Means of activating particular cerebral structures and functions are reviewed, as are the limitations of the techniques with respect to temporal and spatial resolution and the potentially confounding nature of preconceived ideas regarding the mechanisms of brain function.

Brain↗
PubMed1991

Plasma uric acid in patients receiving anticonvulsant monotherapy.

In newly diagnosed adult patients with epilepsy followed prospectively on monotherapy, carbamazepine and phenytoin were associated with a fall in plasma uric acid, but sodium valproate and phenobarbitone were associated with a rise in plasma uric acid. The mechanisms and significance of these findings are discussed.

Adolescent↗
PubMed1990

Vigabatrin: rational treatment for chronic epilepsy.

Vigabatrin is a selective, irreversible suicide inhibitor of GABA transaminase and thus increases brain and CSF GABA. In 33 adult patients with long standing refractory epilepsy on treatment with one or two standard anti-convulsant drugs, the addition of vigabatrin up to 3g daily for eight weeks was associated with a 48.2% reduction in seizure frequency. Twenty patients who had exhibited a 50% or more reduction in frequency of one or more seizure types entered an eight week double-blind placebo controlled phase. Patients on vigabatrin maintained a 54.7% reduction of seizure frequency, whereas those on placebo showed an 18.6% increase in seizure frequency, a highly significant difference between the two groups. In the open phase, seven patients were withdrawn due to unacceptable and reversible adverse events. The commonest side effects were drowsiness, depression and mood instability, and headaches. Vigabatrin is a potentially valuable new treatment for chronic epilepsy, especially partial seizures with or without secondary generalisation.

Adolescent↗
PubMedDate not supplied

Factors relating to dramatic response to clobazam therapy in refractory epilepsy.

Twenty-five out of 41 (61%) patients with drug-resistant complex partial seizures showed an initial dramatic response to clobazam. Sixteen of these responders developed tolerance to the effects of clobazam so that only 9 (22%) maintained a dramatic response for 1 year. Factors which appeared important in predicting a dramatic response to treatment were a known aetiology for the epilepsy, the occurrence of complex partial seizures alone (i.e., without secondary generalisation) and the absence of mental retardation.

Adolescent↗
PubMedDate not supplied

Open, double-blind and long-term study of vigabatrin in chronic epilepsy.

We performed an open, double-blind, and long-term study of vigabatrin (gamma-vinyl-GABA, GVG) in patients with treatment-resistant epilepsy who were receiving only one or at most two standard antiepileptic drugs (AEDs). The novel design included a parallel, double-blind, placebo-controlled phase that minimized the number of patients receiving placebo and allowed determination of the optimum dose of GVG for each patient before initiation of the double-blind phase. The study was divided into four phases. The first phase was a 6-week period of baseline observation. In the second phase, GVG was added openly to previous AEDs for 8 weeks. During the first 2 weeks of this phase, the dose of GVG was increased weekly and then, in the absence of adverse effects, was held constant for the next 6 weeks. At the end of this open phase, seizure frequency during the 6 weeks of constant treatment was compared with the baseline seizure frequency for each patient. Patients who experienced reduction greater than 50% in the frequency of any seizure type during the open phase were defined as responders. These responders were then entered into the third and double-blind phase, in which they were randomly allocated wither to continue active GVG treatment or placebo for 8 weeks. Thirty-three patients entered the study; 31 of 33 patients completed the initial open phase. Twenty patients achieved a reduction greater than or equal to 50% in the frequency of one or more seizure types and were eligible for the double-blind phase; 10 were randomized to continue GVG and 10 were randomized to placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗