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Biomedical subjects

L Bet

Publications and source records attributed to L Bet.

17 recordsLinked to original sources
PubMed1992

Lipid storage myopathy in multiple acyl-CoA dehydrogenase deficiency: an adult case.

A 25-year-old woman had been complaining of episodes of muscle weakness, nausea and vomiting since the age of 10. Muscle biopsy showed free fatty acid accumulation and mitochondrial abnormalities. Mitochondrial DNA appeared to be normal at Southern analysis. Biochemical investigations demonstrated: glutaric aciduria type II, decreased levels of carnitine in liver and values at the lower level of normal in muscle, increased muscle carnitine palmitoyl transferase activity, partial cytochrome c oxidase and succinate cytochrome reductase deficiency in muscle homogenate. In isolated muscle mitochondria, cytochromes aa3, b and c were partially decreased, butyryl-CoA dehydrogenase and palmitoyl-CoA dehydrogenase activities were 10 and 54% of the normal, respectively. Muscle cell cultures did not show lipid storage. Low-lipid diet reduced critical episodes and lipid storage in muscle biopsy.

Acyl-CoA Dehydrogenases↗
PubMed1990

A case of mitochondrial myopathy, lactic acidosis and complex I deficiency.

A 34-year-old man affected by exercise intolerance, mild proximal weakness and severe lactic acidosis is described. Muscle biopsy revealed mitochondrial abnormalities and an increase of cytochrome c oxidase histochemical reaction. Biochemical investigations on isolated muscle mitochondria as well as polarographic studies revealed a mitochondrial NADH-CoQ reductase (complex I) deficiency. Mitochondrial dysfunction was confirmed by 31P nuclear magnetic resonance spectroscopy. Immunological investigation showed a generalized reduction of all complex I polypeptides. Genetic analysis did not reveal mitochondrial DNA deletions. The biochemical defect was not present in the patient's muscle tissue culture. Metabolic measurements and functional evaluation showed a reduced mechanical efficiency during exercise.

Acidosis, Lactic↗
PubMed1990

Kearns-Sayre syndrome: different amounts of deleted mitochondrial DNA are present in several autoptic tissues.

A population of deleted mitochondrial DNA (mtDNA) was found in different amounts in autoptic muscle, heart, cortex, cerebellum, liver and kidney of a patient who died of Kearn-Sayre Syndrome (KSS). The widespread occurrence of the deletion correlates with the multisystem nature of KSS and supports the hypothesis that this is a genetic disease due to an alteration of mtDNA presumably arising in the oocyte or early embryo.

Brain↗
PubMed1989

Muscle glucose-6-phosphate dehydrogenase deficiency.

Muscle glucose-6-phosphate dehydrogenase (G6PD) deficiency is described in four clinically heterogeneous patients: an athlete who developed myoglobinuria after physical exercise; a 7-year-old, mildly mentally retarded boy, who had episodes of dark urine and high creatine kinase; and two brothers of Sardinian origin, the elder showing moderate exercise intolerance. Histochemical and biochemical studies showed a lack of G6PD activity in muscle biopsy specimens as well as in erythrocytes. G6PD characterization in erythrocytes classified these mutant enzymes as Mediterranean variant in all the patients. The deficiency was confirmed in the patients' myotubes and skin fibroblasts, where residual activity was present. Electrophoretic studies in tissue culture extracts showed that the residual muscle enzyme migrated as a single electrophoretic band like normal human muscle G6PD.

Adolescent↗
PubMed1989

Cytochrome c oxidase during human fetal development.

Histochemical, biochemical and immunologic analysis of cytochrome c oxidase (COX) in skeletal muscle, heart and kidney during human fetal development was performed. COX histochemical activity was present only in few muscle fibres from the 11th to the 20th week of gestation. At the same developmental stage intrafusal muscle fibres, heart and kidney already showed strong activity. At the 28th week of gestation muscular COX activity was present in about 90% of the fibres. Tissue biochemical analysis confirmed these histochemical findings. Histochemical and biochemical findings compared to the immunocytochemical results and ELISA indicate that COX activity parallels the progressive synthesis of the enzyme in each tissue.

Electron Transport Complex IV↗
PubMed1989

Endocrine involvement in mitochondrial encephalomyopathy with partial cytochrome c oxidase deficiency.

A 19-year-old man born with thyroprivic hypothyroidism, due to congenital development defect, manifested hypogonadism, stunted growth, chronic progressive external ophthalmoplegia (CPEO), diffuse muscle weakness and wasting, right bundle branch block, cerebral atrophy. Muscle biopsy showed mitochondrial abnormalities. Biochemical investigations on muscle disclosed partial (50%) cytochrome c oxidase deficiency, 58% decrease of cytochrome aa3 and 41% decrease of cytochrome b. Enzyme-linked immunosorbent assay showed decrease of the immunologically active enzyme protein.

Adult↗
PubMed1989

[Mitochondrial encephalomyopathy].

Modern concepts regarding mitochondrial encephalomyopathies (ME) are summarized. Utilizing recent techniques of molecular biology we studied some cases of ME referred to the Institute of Clinical Neurology of Milan University. With these techniques we demonstrated different mitochondrial DNA deletions either in patients' muscle or in culture.

Adolescent↗
PubMed1988

Low doses of ketazolam in anxiety: a double-blind, placebo-controlled study.

A multicenter, double-blind, between-patient trial comparing two doses of ketazolam (15 and 30 mg) with placebo, each given once daily, in the evening, to 92 outpatients affected by generalized anxiety disorders for at least 1 month, was carried out. After 1-week washout period 47 patients were randomized to ketazolam 15 mg, and 45 to placebo for 15 days (first period). At the end of this period, if the patient experienced a decrease on the total Hamilton Anxiety Rating Scale (HAM-A) of at least 25% of basal value, the treatment was kept unchanged for a further 15 days, otherwise 15 mg of ketazolam were added to the previous treatment (second period). Anxiety was rated after 2 and 4 weeks with the Italian HAM-A scale and with a 4-point scale (patient's assessment). Seventy-eight patients completed the first period and 75 the whole study. During the first period the percentage of responders was almost identical in both treatment groups, but during the second period a further slight improvement was observed in the early placebo responders, while the HAM-A score of patients on ketazolam continued to improve significantly (p less than 0.01) throughout the study. Likewise a significant (p less than 0.001) difference between treatments was observed, on the 4-point scale, in the population as a whole (end of first period) as well as in responder patients (end second period). Tolerability was good, except in 1 patient on placebo, who was withdrawn from the study because of severe headache.

Adolescent↗
PubMed1988

Clinical and biochemical correlations in mitochondrial myopathies treated with coenzyme Q10.

We tested the efficacy of coenzyme Q10 (ubidecarenone, CoQ10) therapy in patients with Kearns-Sayre syndrome and other mitochondrial myopathies with chronic progressive external ophthalmoplegia (CPEO). We treated seven patients for 1 year with daily oral administration of 120 mg of CoQ10. Throughout the treatment most of our patients showed a progressive reduction of serum lactate and pyruvate levels following standard muscle exercise and generally improved neurologic functions. The ECG and echocardiogram showed no significant changes in our patients. None of our patients showed any improvement in ptosis and CPEO.

Adolescent↗
PubMed1987

Progressive cytochrome c oxidase deficiency in a case of Kearns-Sayre syndrome: morphological, immunological, and biochemical studies in muscle biopsies and autopsy tissues.

We report biochemical, immunological, and morphological findings in a patient with fatal Kearns-Sayre syndrome. Histochemical and biochemical findings from muscle biopsy specimens obtained 7 years apart documented the disease's evolution from a mild mitochondrial disorder affecting a small proportion of muscle fibers to a severe disorder affecting a large proportion of muscle fibers. Cytochrome c oxidase activity in muscle declined profoundly as the disease progressed, although the level of enzyme protein was normal, as shown by immunochemical techniques. Other organs were severely affected by the disease. Examination of postmortem tissue showed spongiosis in the frontal cortex, diffuse loss of Purkinje cells in the cerebellum, liver steatosis, and heart fibrosis with mitochondrial abnormalities. Cytochrome c oxidase activity was only slightly reduced in these organs.

Adult↗
PubMed1987

Biochemical and immunologic studies in a case of congenital myopathy with unusual morphologic features.

Mitochondria and myosin were isolated from a muscle biopsy of a 9-year-old boy with an unusual congenital myopathy characterized by type I fiber uniformity, jagged Z-line, and transverse network hypertrophy of mitochondria. Biochemical examination of isolated mitochondria showed that only citrate synthase activity was significantly reduced. Electrophoresis of myosin heavy chains and immunoenzymatic analysis of myosin heavy and light chains with antibodies specific to either fast or slow myosins showed that only the slow-type isoform of myosin was detectable. Indirect immunofluorescence of muscle biopsy showed that all muscle fibers homogeneously expressed only the slow type of myosin.

Child↗
PubMed1986

Childhood encephalomyopathy with cytochrome c oxidase deficiency, ataxia, muscle wasting, and mental impairment.

The son of third cousins was normal until age 2 when he had difficulty walking. At age 8 there was limb weakness, ataxia, loss of tendon reflexes, dislalia, and he was mildly retarded. During fasting, urinary organic acid excretion was abnormally high. Cytochrome c oxidase activity in muscle was 7% of the normal mean. The enzyme in platelets was 16% of controls with a decreased cytochrome aa3 peak. These data suggest an autosomal recessive transmission of this variant of cytochrome c oxidase deficiency.

Ataxia↗
PubMed1984

Carnitine and acyltransferase in experimental neurogenic atrophies: changes with treatment.

Carnitine level and carnitine palmityl transferase (CPT) activity were investigated in muscles of patients with infantile and juvenile spinal muscular atrophy and polyneuropathies. A significant decrease of both carnitine and CPT was found in the infantile spinal muscular atrophy, but not in the other neurogenic muscle atrophies. These findings were compared with the experimental effect of denervation and reinnervation upon the lipid metabolism in soleus and extensor digitorum longus (EDL) of adult and newborn rats. Twenty-one days after denervation free and total carnitine decreased significantly in both EDL (P less than 0.001) and soleus (P less than 0.05) of adult animals. CPT activity was significantly decreased in the soleus 50 days after denervation (P less than 0.005). Long-term reinnervation restored the level of carnitine fraction and CPT activity. L-carnitine treatment for 21 days restored the level of free carnitine to normal in the soleus of denervated adult animals. Denervation in newborn rats influenced carnitine concentration in soleus and EDL to a lesser extent; the treatment with L-carnitine raised short-chain acylcarnitines in denervated muscles, while reinnervation restored carnitine level within 50 days.

Acyltransferases↗