Biomedical subjects
Publications and source records attributed to M Pineda.
Two siblings, a boy and a girl, with agenesis of the corpus callosum, apneic spells, attacks of apnea, cyanosis and spontaneous hypothermia, are reported about. Both children died after a few months of life. Postmortem examination revealed a severe spongiosis of the white matter in addition to the agenesis of the corpus callosum and septum pellucidum, in both cases.
The saturation by substrates and cofactors, the effects of pH and the influence of salts and auxiliary enzymes have been studied. The linear NAD+ reduction observed before addition of haemolysate to the assay system was proportional to pH, being higher with phosphate than with Tris-HCl buffer. In the presence of bisphosphoglycerate mutase, an optimal pH (7.8-8.1) was obtained and the inhibition by sulfate ions could be confirmed. It can then be suggested that the absence of an equilibrium, the pH used by several authors and sulfate inhibition could be sources of error in the spectrophotometric assay of bisphosphoglycerate mutase activity. Once optimal conditions have been established, activities found in both human and rat erythrocytes are similar to those given by other accurate methods.
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The kinetics of pyruvate kinase (PK) at various phosphoenol pyruvate (PEP) concentrations, has been studied in cells of the erythrocytic line. The enzyme from erythrocytes shows positive cooperativity, it behaves as michaelian in reticulocytes and shows negative cooperativity in bone marrow cells. ATP exerts an inhibitory effect in all cases. The activator effect of fructose 1,6-bisphosphate (FBP) was found only in erythrocytes.
In mammals, bisphosphoglycerate-synthase activity, whose assay methods are previously discussed, increases gradually along erythropoiesis, leading to a consequent enhancement of 2,3-bisphosphoglycerate formation. Avian erythrocytes, on the other hand, contain inositol-pentaphosphate as major organic phosphate starting from egg eclosion, which substitutes embrionary ATP and 2,3-BPG in the regulatory function. The IHP of phytase and the disappearance of 2,3-BPG synthesis, also inhibitor of enzyme activity, should be considered responsible for IPP accumulation.
Authors present a therapeutic trial with allopurinol on Duchenne muscular dystrophy. On an initial stage of three months they compare the effect of this drug with a placebo, finding no significant results. Afterwards they compare at six weeks, three months and six months the effects on muscle power, chronometered physical exercise and values of CPK without obtaining significant results. The changes on urate serum, and relation urine urate/creatinine are significant at six weeks, three months and six months of treatment.
Clinical characteristics of ten patients with Friedreich's disease are presented. Two cases were members of the same family, another patient had a brother with the disease, and in two cases there was consanguinity. The dominant inheritance pattern was absent in all cases. Initial symptoms and clinical signs were present under 5 years of age in six cases, and in three of them under 2 years of age. As reported in other series, in our cases the disorder first appeared in the legs. Other early manifestations included skeletal deformities and dysarthria, as well as diplopia, paresthesias and dizziness. Friedreich's ataxia results from pyramidal tract degeneration and changes in the cerebellum. Babinski sign was present in nine patients. Other findings were: muscular weakness, distal amyotrophy and distal dystonia. Two patients suffered epileptic attacks with typical EEG pattern. Kyphoscoliosis and pes cavum were constant skeletal deformities. ECG revealed signs of myocardial ischemis in nine patients, although none of them had symptomatology of heart disease. Glucose tolerance test carried out in three cases showed diabetic curves. Results of nerve speed conduction were as follows: normal in one case; decreased sensitive speed conduction in four cases, and decrease of both sensitive and motor speed conduction in other four cases. EMG showed signs of chronic denervation in three cases. These results coincide with those published by other authors.
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A case of "moya-moya" disease of a 12-year-old boy is reported. The clinical history started at 3 years 2 months after cranial trauma. The patient developed mental retardation, hemiparesis and seizures.
A radioimmunoassay was developed for the assay of mibolerone in the serum of adult bitches with a lower limit of detection of 0.5 ng of mibolerone/ml of serum. Serum concentrations in Beagle bitches given mibolerone were found to be dependent on concentration in and type of formulation. The type of formulation also influenced the time to reach peak serum concentrations of mibolerone. Serum concentrations were also different for the same animals treated at 2 geographic locations.
A further case of pyruvate carboxylase deficiency, French type, with a particular clinical presentation and evolution is described. The initial neonatal symptoms started with respiratory distress, severe metabolic acidosis and a tendency to hypoglycemia. However, the clinical course was not rapidly deteriorating. At the age of 6 months he presented acute neurological symptoms, respiratory difficulty, lactic acidosis and hyperammonemia. Amino and organic acid abnormalities strongly suggested pyruvate carboxylase deficiency, which was confirmed by enzymatic studies in cultured fibroblasts and liver necropsy. Progressive deterioration and bronchopneumonia with cardiac failure and renal insufficiency led to death. Anatomic-pathologic studies revealed periventricular cysts and diffuse hypomyelination. Prenatal diagnosis of a further sibling was performed. The neonatal clinical presentation, biochemical abnormalities, and the presence of periventricular cysts suggested a French phenotype. However, the clinical course was less severe, suggesting a residual enzymatic activity and a possible milder mutation.
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When processed by the rapid Golgi method, a significant reduction (P less than 0.002) of the dendritic arborization of Purkinje cells located at the tips of the folia of the rostral vermis was demonstrated in four human cases of cerebellar atrophy, related to chronic alcohol consumption. Except for isolated damaged Purkinje cells located on the depth of the sulci of the rostral vermis in all but one case, no significant differences were observed between alcoholic cases and controls of comparable ages among Purkinje cells located in the remainder of the vermis or the cerebellar hemispheres. These results suggest that structural changes, which precede neuronal death and cell loss, are present in Purkinje cells of the rostral vermis in human cerebellar alcoholic degeneration.
Focal dendritic swellings in secondary dendrites of Purkinje cells were observed in post-mortem samples of the cerebellum processed by the Golgi method from three patients affected by mucopolysaccharidoses (MPS) types I-H, II and III. These focal dendritic swellings exhibited smooth surfaces but secondary formation of spine-like appendages was absent; in contrast, terminal, spiny branchlets were preserved. Complementary electron-microscopical examination of these samples revealed that membranous cytoplasmic bodies and zebra-like inclusions accounted for the material stored in these focal swellings in MPS I-H and MPS II; in addition, granulomembranous cytosomes with fine, densely-packed membranous profiles were encountered in MPS III. Focal dendritic swellings in Purkinje cells may result in abnormal electrical activity, thus producing informational imbalance on the Purkinje cell dendritic arborization in human mucopolysaccharidoses.
BACKGROUND/AIM: Rett syndrome (RTT) is an X-linked neurodevelopmental dominant disorder that affects almost exclusively girls. The disease is mainly sporadic, caused by de novo mutations at MECP2 gene (Xq28), but a low percentage of familial cases have been reported. We present the results of RTT prenatal diagnosis in three families and discuss the usefulness of such analyses in diseases caused mainly by de novo mutations. METHODS: For adult individuals, DNA was extracted from peripheral lymphocytes; for fetus analysis it was obtained from cultured amniotic fluid or from chorionic biopsy specimens. Mutation detection at MECP2 gene was first carried out in the patients by SSCP/HD analysis and subsequent sequencing. Family studies and prenatal diagnoses were done by direct analysis of previously characterized patients' mutations using SSCP/HD or restriction analysis. RESULTS: Heterozygous mutations identified in the 3 patients were: 1061del96bp, 473C-->T, and 763C-->T, respectively. Mutations were not present in the mothers' DNAs obtained from peripheral lymphocytes. None of the 3 fetuses analyzed carried the mutation of the affected sister. CONCLUSIONS: Recurrence within RTT families can be due to asymptomatic nonpenetrant carrier mothers or to parental germinal mosaicism for the MECP2 mutation. Since germline mosaicism can neither be predicted nor detected, families with 1 affected patient whose RTT-causing mutation has been previously identified can benefit from prenatal diagnosis which contributes to a decrease in the recurrence risk in a new pregnancy comparable to that of the normal population.
A posttraumatic cerebellar hematoma in a 12-year-old boy is reported. It was observed by CT scan that the hematoma is discharged incompletely into the subdural space. The surgical treatment was successful with complete recovery. It is suggested that CT scan should be performed as soon as possible in cranial trauma with cerebellar signs.