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Biomedical subjects

F Cornelio

Publications and source records attributed to F Cornelio.

At least 91 records · Page 5Linked to original sources
PubMed1985

Myopathies due to enzyme deficiencies.

After the discovery in 1959 of myophosphorylase deficiency, at least 15 myopathies due to deficiency of enzymes involved in energy substrate utilization have been described. In this review two main categories of enzymopathies, glycogenosis and mitochondrial disorders, are discussed. Clinically, the patients with these categories of enzyme defects present two major syndromes: acute recurrent muscle impairment, generally related to exercise, associated with cramps and/or myoglobinuria; progressive muscular weakness and wasting eventually associated with signs of affected organs other than skeletal muscle. Defects of glycogen breakdown and of the first step of glycolysis are more frequently associated with acute exercise intolerance, such as in myophosphorylase and phosphofructokinase deficiencies, but may be associated with progressive muscle weakness and wasting, such as in acid maltase and debrancher enzyme deficiency. Clinical heterogeneity is common in these disorders, but a biochemical explanation for their different clinical expression is still lacking. Defects of the second step of glycolysis, phosphoglycerate kinase, phosphoglycerate mutase and lactate dehydrogenase deficiencies, have been discovered recently and are associated with exercise intolerance. The reason for muscle weakness and atrophy in glycogenosis is still unclear, although it has been suggested that excessive protein catabolism occurs in myophosphorylase, debrancher and acid maltase deficiencies. Myopathies due to deficiencies of mitochondrial enzymes are less well defined, as a group, than the glycogenoses. They are currently considered to fall into three main groups: defects of substrate utilization, such as carnitine palmitoyltransferase deficiency; defects of respiratory chain complexes, such as cytochrome-c-oxidase deficiency and defects of phosphorylation-respiration coupling, such as Luft's disease. Again, severe and benign exercise intolerance or progressive life-threatening myopathic syndromes may be the clinical expression of these disorders. Detailed biochemical and morphological studies of muscle biopsies are needed in these patients to obtain a definite diagnosis and prognosis, and to decide on eventual treatment.

Adult↗
PubMed1984

Clinical varieties of neuromuscular disease in debrancher deficiency.

Two men and one woman with debrancher deficiency had symptoms and signs of neuromuscular disease. The two men had adult-onset and slowly progressive weakness, distal muscle wasting, "mixed" electromyographic patterns, and slow nerve conduction velocities; the initial diagnosis was Charcot-Marie-Tooth disease in one patient and motor neuron disease in the other. The woman had stunted growth, delayed motor milestones, and lifelong nonprogressive weakness. A muscle biopsy specimen showed severe vacuolar myopathy in all three cases. The glycogen concentration was increased threefold to sixfold and had an abnormal iodine spectrum. Anaerobic glycolysis in vitro showed impaired use of endogenous and exogenous glycogen but normal use of hexose-phosphate glycolytic intermediates. These three cases illustrated the clinical variety of neuromuscular disease in debrancher deficiency. In patients with weakness of adult onset, the diagnosis is impossible to make without performing a muscle biopsy.

Adult↗
PubMed1984

Muscle fiber degeneration and necrosis in muscular dystrophy and other muscle diseases: cytochemical and immunocytochemical data.

Serial consecutive frozen sections from 164 muscle biopsy specimens were studied cytochemically. We localized calcium and albumin as endogenous markers of extracellular fluid penetration and C3 and C9 complement components as markers of muscle fiber necrosis. In both Duchenne dystrophy and congenital muscular dystrophy, a significant percentage of fibers were overloaded with calcium and penetrated by albumin. Most of these fibers appeared opaque with trichrome stain. C3 and C9 complement components appeared only in necrotic fibers, which invariably were also penetrated by albumin. These observations support previous findings that muscle fiber necrosis is linked to massive inflow of extracellular fluid and complement activation. In addition, in both Duchenne and congenital dystrophies, numerous nonnecrotic fibers are penetrated by calcium-rich extracellular fluid.

Albumins↗
PubMed1984

Increased myofibrillar protein catabolism in duchenne muscular dystrophy measured by 3-methylhistidine excretion in the urine.

Myofibrillar protein catabolic rate was calculated in 50 young patients with Duchenne muscular dystrophy from the amount of 3-methylhistidine excreted in the urine, and was found to be about seven times that of a control series, expressed as the percentage of myofibrillar protein catabolized per day. This wastage of myofibrillar protein is a consequence of Duchenne muscular dystrophy and inhibition of protein degradation appears to be one possible approach in the treatment of this disease.

Child↗
PubMed1984

Calcium and magnesium content in fetuses at risk and prenecrotic Duchenne muscular dystrophy.

We measured calcium (Ca) and magnesium (Mg) content in muscles of fetuses at risk of Duchenne muscular dystrophy (DMD) and in a premature infant who later developed typical DMD. There was a three- to six-fold increase in muscle Ca in the fetuses and in the premature infant. In contrast to our previous reports of reduced muscle Mg in DMD children, there was an 18 to 57% increase of Mg in the fetuses at risk. Opaque and Ca-positive fibers, rarely observed in normal fetuses, were numerous in fetuses at risk and in the premature infant. No necrotic fibers were detected in the fetuses or the premature infant. These findings suggest that excessive Ca accumulation precedes necrosis in DMD. Other factors related to growth and development that occur after birth may trigger the necrosis that follows muscle Ca accumulation.

Calcium↗
PubMed1984

Myasthenia gravis: prolonged treatment with steroids.

We have evaluated chronic corticosteroid treatment in 60 myasthenic patients; 92% were followed for more than 3 years and 82% longer than 4 years. Improvement was noted in 72% of the patients. The best results were seen in those whose symptoms started after the age of 40 years. There was a correlation between the starting dose of prednisone and the rate of improvement. Complete withdrawal of steroids was possible only for 3 patients.

Adolescent↗
PubMed1984

Myoadenylate deaminase deficiency in a 5-year-old boy with intermittent muscle pain.

A 5-year-old boy with occasional pain of brief duration at the right or the left leg during exercise since the age of 4 years is reported. There was no weakness nor any other abnormality at the neurological examination. The serum creatine phosphokinase activity was elevated three times out of four. The electromyogram showed myopathic abnormalities in the biceps, it was normal in quadriceps and anterior tibial muscles. A quadriceps muscle biopsy was performed. There were no histological nor histochemical abnormalities at the routine techniques. However, a completely negative reaction with myoadenylate deaminase ( MADA ) stain was found. The MADA enzymatic activity in the muscle was very low. It is likely that the clinical syndrome is related to MADA deficiency.

AMP Deaminase↗
PubMed1983

Congenital myopathy due to phosphorylase deficiency.

A 4-year-old boy had delayed psychomotor development, proximal weakness, increased serum CK, and myopathic EMG. Muscle biopsy was normal, but histochemical stain for phosphorylase showed no reaction. The enzyme defect was confirmed biochemically and in studies of anaerobic glycolysis in vitro. Glycogen concentration was twice normal. Atypical presentations of myophosphorylase deficiency have included progressive weakness of late onset and fatal infantile myopathy. This patient represents another example of clinical heterogeneity.

Child, Preschool↗
PubMed1982

Functional evaluation of Duchenne muscular dystrophy: proposal for a protocol.

A protocol for the evaluation of functional activities in subjects with Duchenne muscular dystrophy (DMD) was designed. The aim of our study was to define objective clinical criteria for the evaluation both of the clinical status of the patient and of the natural history of the illness itself. A protocol with such criteria is particularly necessary when testing the efficacy of treatment. 43 still-ambulant children with DMD between the ages of 3.10 yr and 10.4 yr were examined. Of this number 19 children were evaluated every 4 months over a period of 12 months; of these 14 formed part of a randomized double blind trial with L-carnitine (1.2-1.8 g/day) versus placebo.

Carnitine↗
PubMed1982

Plasma exchange combined with cytotoxic drugs and lymphocytapheresis for myasthenia gravis.

20 patients with myasthenia gravis (MG), refractory to anticholinesterase and steroid therapy, underwent plasma exchange therapy combined with immunosuppressive drugs and lymphocytapheresis. In all these patients an apparent clinical improvement was obtained since their first exchange session. During a follow-up of 8-18.5 months, a long-lasting benefit was achieved in 16 patients even though 6 of these had a single recurrence shortly after their first apheretic cycle. 3 patients who achieved substantial improvement of their symptoms during plasmapheresis showed recurrence of weakness after each apheretic course was stopped. However, their clinical response to therapy tended to improve with the following courses, which would be consistent with the effects of immunosuppression. This study strongly suggests that plasma exchange combined with immunosuppressive drugs and lymphocytapheresis can bring about dramatic and sustained improvement of MG and may alter its natural history.

Azathioprine↗
PubMed1981

Systemic carnitine deficiency with peripheral nerve involvement morphological and biochemical study.

The patient, a 31-year-old woman, suffered from a weakness of the proximal muscles which subsequently worsened involving the spinal and neck muscles. During the hospitalization, the patient displayed a "burning feet" syndrome. Lab tests showed a moderate increase in CPK, Aldolase, SGPT, SGOT, lactic and pyruvic acids. Needle EMG was interpreted as "myopathic" but a marked reduction of sensitive action potentials was also detected. Muscle biopsy showed neutral lipid accumulation in muscle fibers, many small angular fibers, probably denervated ones were also evident. A liver biopsy showed fatty accumulation in hepatocytes. Free carnitine was extremely reduced in muscle and liver and just below normal level in plasma while there was a tenfold elevation of long-chain carnitine esters in plasma too. The mechanism by which carnitine deficiency can cause both neural and muscular alterations and in particular the role of carnitine in glucose metabolism is discussed.

Adult↗
PubMed1981

Myasthenia gravis. Anti-acetylcholine receptor antibodies.

Human acetylcholine receptor and the Lefvert method (13) were used to determine the serum levels of anti-acetylcholine receptor antibodies in 27 patients with Myasthenia Gravis. Antibodies were detected in 22 patients (81%). Negative results were generally obtained in patients having milder forms of the disease. To find out whether serum levels of antibodies correlate with the severity of the disease, we compared the median antibody levels in patients with Type 1 and 2A Myasthenia Gravis with those of patients with type 2B and 3. Significantly lower titers were observed in the first group. Nevertheless, there were many overlapping values in the range of each class of the disease. A more definite relationship was observed in the follow-up of single patients. As a rule, clinical deterioration was accompanied by an increase of antibody levels and viceversa.

Adult↗
PubMed1981

Heterogeneity of carnitine-palmitoyltransferase deficiency.

Episodes with muscle ache, rhabdomyolysis and myoglobinuria with or without associated renal insufficiency are characteristic of muscle carnitinepalmitoyltransferase (CPT) deficiency. However, patients differ from each other in many aspects, such as the kind of stimulus that triggers rhabdomyolysis, the ability to produce ketone bodies when fasting, whether the enzyme defect is localized in skeletal muscle or is general, and the nature of the enzyme defect, which may be in CPT I or CPT II or both. Studies of muscle, liver and fibroblasts from a patient with recurrent rhabdomyolysis spontaneously occurring or triggered by exercise or fever, revealed a CPT deficiency in the muscle and liver biopsy samples but normal CPT activity in cultured cells, differing from previously reported patients. The enzyme defect in muscle was evidenced by two different methods, but not when determined with a method that measures the formation of palmitoylcarnitine. The enzyme abnormality in the patient's liver was associated with a delayed ketone body production and with a dramatic increase in long-chain acylcarnitines in the serum when fasting. Moreover the patient was unable to build up ketones when fed long-chain triglycerides (LCT) but showed prompt ketogenic response when fed medium-chain triglycerides (MCT). The heterogeneity of clinical presentations and of the biochemical findings in patients with CPT deficiency are discussed.

Acute Kidney Injury↗
PubMed1980

Ketogenic response to fasting in human carnitine deficiencies.

Carnitine and its short-chain and long-chain esters have been determined in muscle and liver of two patients with carnitine-deficient myopathy. Plasma carnitines and ketone bodies were monitored in the two patients during a 38-h fast. The two patients showed different ketogenic responses to the fast. One patient, with carnitine deficiency restricted to skeletal muscle, had exaggerated ketone production on fasting. The other patient, with carnitine deficiency in skeletal muscle and liver, had poor ketone body production on fasting. It is assumed that the presence of adequate levels of carnitine in the liver are crucial for the activation of ketogenic machinery in liver.

Adult↗