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Biomedical subjects

G G Gascon

Publications and source records attributed to G G Gascon.

At least 55 records · Page 3Linked to original sources
PubMed1991

Cytogenetic investigations in three cell types of a Saudi family with ataxia telangiectasia.

Chromosomal analyses were performed on lymphocytes, fibroblasts and lymphoblastoid cell lines derived from a Saudi family with ataxia telangiectasia (AT). The three siblings of a consanguineous marriage were all affected. The lymphocytes of the AT homozygotes (probands) showed an increase of 2- to 6-fold and 4- to 8-fold respectively, in the frequency of spontaneous and X-ray-induced chromosomal aberrations compared with controls, while the parents (obligate heterozygotes) of the patients showed no notable difference. The unirradiated lymphocytes from the oldest AT sibling, an 11-year-old boy (AT1), showed specific rearrangements involving chromosomes 7 and 14 [t(7;14)(q35;q12)] and 12 and 14 [t(12;14)(q23;q12)] in two different clones. The most severely affected sibling was a 9-year-old girl (AT2) who presented with a clone showing a novel rearrangement involving chromosomes 14 and 17, namely: del(14) (q31q32) and dup(17)(q21-q24). The lymphocytes from the third sibling, a 2-year-old boy (AT3), showed a t(2;14)(p24;q12). In addition, an inv(14)(q12q32) was observed in all three AT patients, while inv(7)(p14q35) was found only in patients 2 and 3. The lymphocytes from the AT parents and controls showed normal karyotypes. The breakpoints involving chromosomes 2, 12 and 17, observed in our studies, have rarely been reported in other series of AT patients. No non-random chromosomal rearrangements were observed either in the skin fibroblasts or in the lymphoblastoid cell lines derived from the AT patients, although all cell lines showed an increase in both spontaneous and radiation-induced chromosomal breaks per cell. The present study constitutes the first report on a cytogenetic analysis of a Saudi family with three AT siblings.

Ataxia Telangiectasia↗
PubMed1991

Organic acidurias: a review. Part 1.

Organic acidemias are disorders of intermediary metabolism that lead to accumulation of organic acids in biologic fluids, disturb acid-base balance, and derange intracellular biochemical pathways. Their clinical presentation reflects the resultant systemic disease and progressive encephalopathy. While in some organic acidemias, disturbed acid-base metabolism is the predominant presenting feature, in others it is less prominent or even absent. The etiologies of the more than 50 different phenotypes include impaired metabolism of branched-chain amino acids, vitamins, glucose, lipids, glutathione, and gamma-aminobutyric acid and defects of oxidative phosphorylation. Most organic acidemias present with neurologic manifestations, which include acutely or subacutely progressive encephalopathy that involves different parts of the nervous system. The age of presentation and the associated systemic, hematologic, and immune findings provide additional guidelines for differential diagnosis. We summarize major organic acidemias, while emphasizing their usual and unusual neurologic presentations.

Acid-Base Imbalance↗
PubMed1991

Organic acidurias: a review. Part 2.

Laboratory findings are an essential part of the diagnostic approach to organic acidemias. In most organic acidemias, metabolism of glucose, ketone bodies, and ammonia is deranged primarily or secondarily, in addition to derangement of the acid-base balance. Hypoglycemia, lactic and/or ketoacidosis, and hyperammonemia of varying severity accompany the overt or compensated acidosis. In most instances, a definite diagnosis will be achieved by gas chromatography/mass spectrometry (GC/MS) studies of the urine. We detail the pattern of excreted organic acids in the major disorders. When the diagnosis reached by clinical and laboratory assessments is not conclusive, it must be supported by loading tests. We list the available methods of demonstrating the putative enzyme deficiency in the patient's cells and tissues. The majority of organic acidemias may be treated by limiting the source of or removing the toxic intermediary metabolite. We provide lists of available diets, supplements, and medications. In some instances, residual defective enzyme activity may be stimulated. We describe symptomatic management of the disturbed acid-base and electrolyte balance.

Acidosis↗
PubMed1990

Aspartoacylase deficiency and Canavan disease in Saudi Arabia.

We found defective aspartoacylase activity in fibroblasts cultured from 12 patients with leukodystrophy clinically diagnosed as spongy degeneration of the brain (Canavan disease), three confirmed by brain biopsy. The activity of aspartoacylase ranged between 1 and 13% of two groups of control individuals, normals, and those with other leukodystrophies. The present report confirms the study of Matalon et al. [1988] in a totally different ethnic group and provides independent verification that aspartoacylase activity is the first documented specific biochemical marker in Canavan disease and plays an important role in pathogenesis. Considering that only some 75 cases had been reported up to 1982, our group of 12, accumulated within 3 years, is inordinately large and suggests that Saudi Arabia provides a promising venue in which to study the biochemical and molecular genetics of Canavan disease.

Amidohydrolases↗
PubMed1990

Phenotypic heterogeneity of spinal muscular atrophy mapping to chromosome 5q11.2-13.3 (SMA 5q).

We made phenotypic analysis of 14 families with spinal muscular atrophy (SMA) linking to chromosome 5q11.2-13.3 (SMA 5q), and 2 that may not map to this locus, to assess clinical symptoms among SMA families known to result from mutation at the identical gene/locus. Although the current number of families is still small, the correlation of clinical phenotype and molecular genotype supports 2 observations. First, SMA mutations at the 5q locus present with a broad continuum of clinical abnormalities, and 2nd, the single clearly unlinked family presents with an unusual phenotype characterized by relatively late onset and early death. Thus, there are as yet no unambiguous cases of typical SMA families that are clearly unlinked to the locus at 5q-ie, no clear cases of nonallelic heterogeneity. Analysis of SMA 5q families supports the view that, with certain exceptions, there is little phenotypic intrafamilial variability. When families were ranked by severity of disease there was a strong correlation with age of onset. Onset within the 1st few months was associated with early death, but not in all cases. With rare exception, onset after 1 year of age was associated with less severe disease and greater longevity.

Chromosome Mapping↗
PubMed1990

Infantile CNS spongy degeneration--14 cases: clinical update.

We studied 14 Arab infants with infantile spongy degeneration, 13 of whom were products of consanguineous marriages. They presented in infancy with macrocephaly, poor visual behavior or blindness, and axial hypotonia with appendicular spasticity. Brain CT and MRI showed diffuse symmetric leukoencephalopathy, even before neurologic symptoms. There were relatively normal EEGs. The visual evoked responses (P100) were either absent or delayed early in the course. The brainstem auditory evoked responses showed milder abnormalities, with loss of later components before the earlier ones. Deficient aspartoacylase activity in cultured fibroblasts or brain biopsy confirmed the diagnosis in all patients.

Amidohydrolases↗
PubMed1989

A pilot controlled study of the use of imipramine to reduce myotonia.

It has been hypothesized that myotonic dystrophy is caused by a generalized disorder of membrane aminergic and petidergic receptors. A single uncontrolled study has suggested that the affective symptomatology and muscular disability of this disorder might be improved by tricyclic antidepressant treatment. In the present study, 12 adult patients with myotonic dystrophy (age range 18-55 yr) were treated with imipramine and placebo in a double-blind crossover paradigm. Both grip and percussion myotonia were significantly improved by imipramine treatment independent of change in depressive symptomatology. Serum drug levels revealed nonlinear elimination kinetics for imipramine in this patient population.

Adult↗
PubMed1988

Pure word deafness (acquired verbal auditory agnosia) in an Arabic speaking patient.

A 38-year-old, right-handed Arabic-speaking male developed pure word deafness three days after myocardial infarction. He could recognize Arabic music and instruments but not words of songs; a radio broadcast from the Koran, but not the individual words; a male as opposed to female voice; Arabic and non-Arabic languages; and whether sentences were questions, exclamations, or imperatives. He discerned whether the speaker was emotionally neutral, happy, angry or sad. Contextual cues and reducing the rate of speaking aided verbal comprehension. Pure tone threshhold audiometry revealed mild bilateral sensorineural loss up to 2000 Hz and a moderate high frequency loss. Brainstem auditory evoked potentials were normal, cortical auditory evoked potentials abnormal. CT scan revealed bilateral infarcts subcortically just posterior to the left superior temporal gyrus and the right posterior superior and midtemporal regions. Neurolinguistic tests indicated that the deficit is prephonemic and not due to impairment of linguistic discrimination.

Acoustic Stimulation↗
PubMed1988

Rett syndrome: review and discussion of current diagnostic criteria.

Rett syndrome is a mental retardation syndrome that occurs only in females and consists of normal pre-, peri-, and neonatal growth and development. It is followed by rapid neurobehavioral deterioration in late infancy or early childhood, a developmental arrest, plateauing, and then either a course of retarded development or continued deterioration. The period of rapid neuro-behavioral deterioration manifests as a partial autistic syndrome, with loss of production and comprehension of language, hyperactivity, hyperventilation, hand-wringing, and ataxic gait. Current diagnostic criteria are discussed and suggestions for further research are presented.

Autistic Disorder↗
PubMed1986

Central auditory processing and attention deficit disorders.

Nineteen children who met criteria for attention deficit disorder (ADD) received neurodevelopmental attention testing and central auditory processing (CAP) tests. The CAP tests consisted of the Staggered Spondaic Word (SSW) test and the Willeford battery of tests. Teacher and parent questionnaires (originally devised at the Learning Disabilities Clinic, The Children's Hospital, Boston) were obtained. There was a very high concordance between the questionnaires and the CAP tests, but a low concordance between the neurodevelopmental measures and the questionnaires. After treatment with central nervous system stimulants, there was again a high concordance between teacher/parent reports and CAP measures, and less than 50% concordance between neurodevelopmental measures and teacher/parent observations. We conclude that the SSW and Willeford battery are sensitive performance indicators of attention disorder. Furthermore, these tests are more useful in titrating response to CNS stimulants than neurodevelopmental assessments and provide objective support for the subjective teacher and parent observations.

Adolescent↗
PubMed1984

Chronic and recurrent headaches in children and adolescents.

Headache is a common chronic and recurrent symptom in children and adolescents. The author discusses the prevalence of headache, its differential diagnosis, interpretation of symptoms, methods of assessment, and pharmacologic and nonpharmacologic treatment approaches.

Adolescent↗
PubMed1973

Limbic dementia.

This is the second reported case, known to the authors, of complete, but selective, limbic lobe destruction in previously normally functioning central nervous systems. Both cases had an amnestic syndrome, whose characteristics were essentially similar to amnestic syndromes previously documented with less complete limbic destruction, with one difference-confabulation remained a prominent feature in the chronic stages of the memory disorder. Our patient exhibited a behavioural syndrome similar to that reported by Klüver and Bucy in monkeys with bilateral anterior temporal lobectomies. Klüver-Bucy like syndromes in man have usually been reported with surgical lesions, usually in patients with pre-existent brain disorder. Our case illustrates that the syndrome can be produced by necrotizing encephalitic lesions. We suggest that the combination of the above two syndromes is essentially a `limbic dementia'.

Adult↗
PubMedDate not supplied

Chorea as a presentation of herpes simplex encephalitis relapse.

Three infants, ages 3 months to 3 years, presented with chorea as the initial manifestation of herpes simplex encephalitis (HSE) relapse. Patient 2, treated with repeated 10 day courses of 30 mg/kg/day of acyclovir, had no clear improvement in neurological status. Patient 1, treated with a repeated 10-day course, improved only to have another HSE relapse 4 years later. Patient 3 clearly improved soon after a 3-week course of acyclovir at conventional dosages. A fourth patient (Patient 4) who relapsed with chorea after what was thought to be HSE, and who did not respond to repeated acyclovir treatment, was negative for herpes simplex virus indicators on brain biopsy and DNA testing. We recommend treating all patients suffering from HSE with a minimum 3-week course of acyclovir at 30-35 mg/kg/day in 3 divided doses.

Brain↗