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Biomedical subjects

E Bonilla

Publications and source records attributed to E Bonilla.

At least 163 records · Page 9Linked to original sources
PubMed1989

Mitochondrial DNA deletions in progressive external ophthalmoplegia and Kearns-Sayre syndrome.

We investigated the correlations of deletions of mitochondrial DNA in skeletal muscle with clinical manifestations of mitochondrial myopathies, a group of disorders defined either by biochemical abnormalities of mitochondria or by morphologic changes causing a ragged red appearance of the muscle fibers histochemically. We performed genomic Southern blot analysis of muscle mitochondrial DNA from 123 patients with different mitochondrial myopathies or encephalomyopathies. Deletions were found in the mitochondrial DNA of 32 patients, all of whom had progressive external ophthalmoplegia. Some patients had only ocular myopathy, whereas others had Kearns-Sayre syndrome, a multisystem disorder characterized by ophthalmoplegia, pigmentary retinopathy, heart block, and cerebellar ataxia. The deletions ranged in size from 1.3 to 7.6 kilobases and were mapped to different sites in the mitochondrial DNA, but an identical 4.9-kilobase deletion was found in the same location in 11 patients. Biochemical analysis showed decreased activities of NADH dehydrogenase, rotenone-sensitive NADH-cytochrome c reductase, succinate-cytochrome c reductase, and cytochrome c oxidase, four enzymes of the mitochondrial respiratory chain containing subunits encoded by mitochondrial DNA. We conclude that deletions of muscle mitochondrial DNA are associated with ophthalmoplegia and may result in impaired mitochondrial function. However, the precise relation between clinical and biochemical phenotypes and deletions remains to be defined.

Blotting, Southern↗
PubMed1989

Cell fractionation studies indicate that dystrophin is a protein of surface membranes of skeletal muscle.

We studied the subcellular localization of dystrophin in rabbit skeletal muscle. In Western-blot analysis of membrane preparations, dystrophin was associated with the sarcolemmal fraction, as indicated by cholesterol content and co-purification with ouabain-binding activity and beta-adrenergic receptor. Dystrophin was also found with junctional T-tubules, but not with 'free' T-tubules, longitudinal portions or terminal cisternae of the sarcoplasmic reticulum. Dystrophin was not solubilized by high salt solutions, but it was solubilized by low concentrations of detergents (Triton X-100 and deoxycholate), suggesting that it is a peripheral membrane protein.

Animals↗
PubMed1989

Dystrophin immunocytochemistry in muscle culture: detection of a carrier of Duchenne muscular dystrophy.

Dystrophin is the gene product which is affected in Duchenne muscular dystrophy (DMD). We studied differentiating clonal muscle cultures derived from normal muscle and from the mother of a DMD patient by immunocytochemistry, using anti-dystrophin antibody. While clonal cultures derived from normal muscle expressed dystrophin in all myotubes, two populations of myogenic cells could be demonstrated in muscle from this possible DMD carrier; in 13 clones the myotubes expressed dystrophin and in 7 clones dystrophin was undetectable. No DNA deletion, duplication or rearrangement was detected by Southern blot analysis of DNA from this family using cDNA probes. Thus, immunocytochemical analysis of clonal muscle cultures may be a useful method to determine whether mothers of DMD patients are carriers of the DMD mutation, especially in the absence of demonstrable gene defects.

Adult↗
PubMed1989

Myoclonic epilepsy and ragged-red fibers with cytochrome oxidase deficiency: neuropathology, biochemistry, and molecular genetics.

A 36-year-old man with myoclonic epilepsy and ragged-red fibers (MERRF) died after more than 18 years of follow-up study. He was 1 of 3 affected siblings and the offspring of an affected mother, suggesting maternal transmission. At autopsy, there was neuronal loss and gliosis in the dentate nucleus of the cerebellum and in the inferior olivary nucleus. Skeletal muscle showed ragged-red fibers, and paracrystalline inclusions in mitochondria by electron microscopy. Biochemical analysis showed a generalized partial defect of cytochrome c oxidase (COX) in mitochondria isolated from all tissues, including brain, heart, skeletal muscle, kidney, and liver. The Michaelis constant (Km) for cytochrome c was abnormally low, suggesting a defect of the mitochondrially encoded subunit II of COX. Immunological studies (enzyme-linked immunosorbent assay, dot-blot, Western blot, and immunohistochemistry) showed that the holoenzyme was decreased but subunit II was decreased more than the holocomplex or the nuclearly encoded subunit IV. However, Northern and Southern blots showed that the gene for subunit II, as well as the genes for subunits I, III, IV, and VIII, were of normal size and were normally transcribed. A point mutation or a small deletion of mitochondrial DNA, probably affecting the COX-II gene, may be responsible for the COX deficiency in this case of MERRF.

Adolescent↗
PubMed1989

Detection of "deleted" mitochondrial genomes in cytochrome-c oxidase-deficient muscle fibers of a patient with Kearns-Sayre syndrome.

Using in situ hybridization and immunocytochemistry, we studied a muscle biopsy sample from a patient with Kearns-Sayre syndrome (KSS) who had a deletion of mitochondrial DNA (mtDNA) and partial deficiency of cytochrome-c oxidase (COX; EC 1.9.3.1). We sought a relationship between COX deficiency and abnormalities of mtDNA at the single-fiber level. COX deficiency clearly correlated with a decrease of normal mtDNA and, conversely, deleted mtDNA was more abundant in COX-deficient fibers, especially ragged-red fibers. The distribution of mtRNA had a similar pattern, suggesting that deleted mtDNA is transcribed. Immunocytochemistry showed that the nuclear DNA-encoded subunit IV of COX was present but that the mtDNA-encoded subunit II was markedly diminished in COX-deficient ragged-red fibers. Because the mtDNA deletion in this patient did not comprise the gene encoding COX subunit II, COX deficiency may have resulted from lack of translation of mtRNA encoding all three mtDNA-encoded subunits of COX.

Base Sequence↗
PubMed1989

Nutritional evaluation of Huntington disease patients.

A nutritional survey and evaluation was made in Huntington disease patients by the 24-h-recall method. Control subjects and choreic patients consumed a diet that supplied all the essential amino acids. The diet was hypocaloric, rich in animal protein, and low in fat and carbohydrates. The ratio of calcium to phosphorus in the groups studied was less than 1. High vitamin A and low vitamin C and niacin intakes were observed in Huntington disease patients. Only 17% of control subjects showed weight deficiency; 55% of the patients at stages III and IV of the disease were malnourished despite receiving the same food intake as controls. Although iron intake was deficient in all groups studied, it was enough to maintain normal serum levels of this metal. The deficiencies found in some nutrients do not explain the clinical manifestations observed in Huntington disease patients.

Adolescent↗
PubMed1989

[Venezuelan equine encephalitis. Review].

The Venezuelan equine encephalomyelitis (VEE) is one the most serious viral infections of the nervous system. It has a wide geographic distribution and may give rise to sequela like mental retardation, amnesia, abortion, epilepsy and hidroanencephaly in infected humans and animals. The pathology of this infection is focused mainly in two tissues: lymphohematopoietic and nervous. The VEE virus has a special cytopathic activity on the nervous cells (glia and neurons) while the lesions produced in the myelin are probably a consequence of the immunological response of the host to the infection. The alterations produced by the VEE virus in different neuronal types can originate changes in the brain concentrations of several neurotransmitters and their receptors. Some biochemical modifications that have also been reported could be due to the cytopathic effect of the virus.

Encephalomyelitis, Venezuelan Equine↗
PubMed1989

[Blood levels of zinc in normal subjects].

Zinc serum concentrations were studied by flameless atomic absorption spectrophotometry in normal subjects at the Blood Bank of Maracaibo, Venezuela. We analyzed 487 serum samples: 444 from males and 43 from females. The concentration detected was 84 +/- 20 (mean +/- S.D.) microgram Zn/100 ml. The statistical analysis of data did not show any significant differences between age and sex in the groups studied. No-functional relationship was determined between zinc serum concentrations and age and sex of subjects.

Adolescent↗
PubMed1989

[Family with a high frequency of schizophrenic disorder. Preliminary report].

We studied the clinical features of seven schizophrenic patients detected in seven generations of a pedigree where a high incidence of psychiatric diseases was found. Two psychiatrists, acting independently, conducted a clinical evaluation of each patient using DSM-III and DSM-III-R criteria. Four of the schizophrenic patients are siblings and come from a schizophrenic mother, who also has a brother and a cousin affected with this disorder. Four of the patients were diagnosed as Paranoid; two as Undifferentiated and one patient as Residual Schizophrenia. The family members are exposed to the same psychosocial and environmental influences including climate, nutrition and health care. Most of the patients in this family are male. We found an elevated consanguinity rate. Our findings show the high familiar prevalence of Schizophrenia. In this family the disease seems to be inherited as an autosomal recessive disorder.

Adolescent↗
PubMed1989

Characterization of SV40-transformed human cells by immunofluorescence and fluorescent in situ hybridization techniques.

We have performed immunofluorescent and fluorescent in situ hybridization studies in order to better clarify the integration of SV40 DNA in human fibroblast cell lines. Most of the cells were T-antigen positive by immunocytochemical studies, while in all the cells we detected the integrated viral DNA by in situ hybridization. Both techniques are easy and useful to perform but the molecular genetic method gives a more specific signal with the possibility of localizing molecular hybrids in the nucleus and in the cytoplasm of the transformed cells.

Antigens, Polyomavirus Transforming↗
PubMed1989

Mitochondrial diseases.

Mitochondrial diseases, and particularly mitochondrial myopathies or encephalomyopathies, have drawn increasing attention in the past decade. Initially defined by morphologic changes in muscle ("ragged red fibers" and ultrastructural abnormalities of mitochondria), mitochondrial encephalomyopathies can now be classified according to biochemical defects involving: (1) mitochondrial transport; (2) substrate oxidation; (3) Krebs cycle; (4) respiratory chain; and (5) oxidation-phosphorylation coupling. For each biochemical group of disorders, the authors describe clinical presentations and biochemical findings. These disorders are especially interesting from the genetic point of view because mitochondria have their own DNA (mtDNA), which encodes 13 polypeptides, all of them subunits of respiratory chain complexes. Other mitochondrial proteins are encoded by nuclear DNA, synthesized in the cytoplasm, and imported into the mitochondria by a complex mechanism. Because mtDNA is inherited strictly by maternal, cytoplasmic inheritance, mitochondrial diseases can be transmitted by Mendelian or by non-Mendelian, maternal inheritance, as illustrated by human pathology.

Brain Diseases, Metabolic↗
PubMed1989

Mitochondrial encephalomyopathies.

Increasingly numerous studies are being devoted to mitochondrial diseases, notably those which involve the neuromuscular system. Our knowledge and understanding of these diseases is progressing rapidly. We owe to Luft et al. (1962) the first description of this type of diseases. Their patient, a woman, presented with clinical symptoms suggestive of mitochondrial dysfunction, major histological abnormalities of skeletal muscle mitochondria and defective oxidative phosphorylation coupling clearly demonstrated in mitochondria isolated from muscle. This clinical, histological and biochemical triad led to the definition of mitochondrial myopathies. Subsequently, the triad was seldom encountered, and most mitochondrial myopathies were primarily defined by the presence of morphological abnormalities of muscle mitochondria. This review deals with the morphological, clinical, biochemical and genetic aspects of mitochondrial encephalomyopathies. The various morphological abnormalities of mitochondria are described. These are not specific of any particular disease. They may be present in some non-mitochondrial diseases and may be lacking in diseases due to specific defects of mitochondrial enzymes (e.g. carnitine palmityl-transferase or pyruvate dehydrogenase). The clinical classification of mitochondrial encephalomyopathies is discussed. There are two main schools of thought: the "lumpers" do not recognize specific syndromes within the spectrum of mitochondrial "cytopathies", the "splitters" try to identify specific syndromes while recognizing the existence of borderline cases. The following syndromes are described: chronic progressive external ophthalmoplegia (CPEO), Kearns-Sayre syndrome (KSS), MERRF syndrome (myoclonic epilepsy with ragged-red fibers), MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) and Leigh and Alpers syndromes. The biochemical classification comprises five types of abnormalities: defects of transport through the mitochondrial membrane, of substrate utilization, of Krebs' cycle, of oxidative phosphorylation and of various complexes of the respiratory chain. The clinical pictures corresponding to these defects are briefly described. The genetic aspects of these diseases are especially interesting because mitochondria have their own genome coding for thirteen proteins, all of them belonging to the respiratory chain. Genetic mitochondrial diseases may result from alterations of the nuclear genome, which are transmitted by mendelian inheritance, but they may also be due to alterations of the mitochondrial genome and transmitted by non-mandelian "maternal" heredity. A few examples are discussed, including Leber's optic atrophy and MERRF syndrome. (ABSTRACT TRUNCATED AT 400 WORDS)

Brain Diseases, Metabolic↗
PubMed1988

Duchenne muscular dystrophy: deficiency of dystrophin at the muscle cell surface.

Dystrophin is the altered gene product in Duchenne muscular dystrophy (DMD). We used polyclonal antibodies against dystrophin to immunohistochemically localize the protein in human muscle. In normal individuals and in patients with myopathies other than DMD, dystrophin was localized to the sarcolemma of the fibers. The protein was absent or markedly deficient in DMD. The sarcolemmal localization of dystrophin is consistent with other evidence that there are structural and functional abnormalities of muscle surface membranes in DMD.

Cell Membrane↗
PubMed1988

Molecular defects in cytochrome oxidase in mitochondrial diseases.

Defects of cytochrome c oxidase (COX) show remarkable clinical, biochemical, and genetic heterogeneity. Clinically, there are two main groups of disorders, one dominated by muscle involvement, the other by brain dysfunction. Biochemically, the enzyme defect may be confined to one or a few tissues (reflecting the existence of tissue-specific isozymes) or affect all tissues. Immunologically reactive enzyme protein is decreased in some forms of COX deficiency but not in others. Because COX is encoded both by nuclear and by mitochondrial genes, COX deficiencies may be due to mutations of either genome and may offer useful models to study the communication between nuclei and mitochondria. We have isolated full-length cDNA clones encoding human COX subunits IV, Vb, and VIII and a partial-length clone for subunit Va. These clones are being used as probes to analyze the DNA and RNA of patients with COX deficiency.

Brain Diseases↗
PubMed1988

Changes in serum and striatal free amino acids after Venezuelan equine encephalomyelitis virus infection.

The infection with the Venezuelan equine encephalomyelitis virus produced a significant increase in the concentration of alanine, arginine, asparagine, glutamine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, tyrosine, and valine in the striatum of rats. On the contrary, the concentrations of aspartate, GABA, glutamate, and taurine were reduced. Arginine, aspartate, glycine, methionine, phenylalanine, taurine, and tyrosine concentrations were increased in the serum of infected rats. However, the modifications in the content of free amino acids in the striatum and serum of rats that survived the infection were qualitatively and quantitatively different from those detected during the acute phase of the infection.

Amino Acids↗
PubMed1988

Huntington's disease: studies on brain free amino acids.

We studied the levels of free amino acids in putamen and Brodmann's area 10 of 12 patients who died with Huntington's disease and 13 non-neurologic controls. GABA, glutamate and alpha-amino-n-butyric acid concentrations were found to be reduced in putamen of Huntington's disease patients. In Brodmann's area 10 the levels of glutamate, histidine and lysine were decreased, but the content of aspartate, GABA, glycine, serine and taurine was increased in the same group of patients.

Adult↗
PubMed1988

Cloning and expression of human nebulin cDNAs and assignment of the gene to chromosome 2q31-q32.

We have isolated two nonoverlapping cDNAs encoding human nebulin, a muscle-specific protein. Northern hybridization analysis shows that nebulin is encoded by a huge message at least 25 kb in length. By hybridizing two nonoverlapping cDNAs to DNA isolated from rodent X human cell hybrids, we assign this presumably single-copy gene to human chromosome 2; sublocalization studies indicate that the nebulin gene is on the long arm of the chromosome, in the region 2q31-q32.

Amino Acid Sequence↗