Lysosomotropic agents induce morphological and functional changes in human muscle cells in vitro.

We studied the distribution of lysosomes in differentiating human muscle cells in culture treated with propranolol, leupeptin and chloroquine. Chloroquine treated cells showed a significant vacuolization and an increase of the lysosomal apparatus as assessed by cytochemical analysis of the lysosomal enzyme acid phosphatase and by acridine orange staining. At electron microscopic level, an increase of lysosome-like bodies and disorganization of the contractile apparatus were demonstrated in multinucleated myotubes.

Nucleus-driven multiple large-scale deletions of the human mitochondrial genome: a new autosomal dominant disease.

We studied several affected and one nonaffected individuals belonging to three unrelated pedigrees. The pathological trait was an autosomal dominant mitochondrial myopathy due to large-scale multiple deletions of the mitochondrial genome. Clinically, symptomatic patients had progressive external ophthalmoplegia, muscle weakness and wasting, sensorineural hypoacusia, and, in some cases, vestibular areflexia and tremor.

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.

Immunogenicity of Haemophilus b conjugate vaccine (meningococcal protein conjugate) in children with prior invasive Haemophilus influenzae type b disease.

Children younger than 2 years of age with previous invasive Haemophilus influenzae (Hib) type b disease may not develop protective antibodies to antigens of Hib and may be at risk of developing a second episode of Hib disease. Twenty-three children with prior Hib disease were immunized with Haemophilus b conjugate vaccine (meningococcal protein conjugate). Children 12 to 24 months of age were given one dose of vaccine and children younger than 12 months of age were given 2 doses 2 months apart.

Quantitative assessment of class II molecules in normal and pathological nerves. Immunocytochemical studies in vivo and in tissue culture.

We have analysed class II molecules (HLA-DR) expression in human fetal nerves at different stages of gestation, in human control nerves and in nerves of patients with peripheral neuropathies of different aetiology. Immunochemical demonstration of HLA-DR antigens was also performed on isolated human Schwann cells at different times in culture, from the same nerves. In normal nerves, HLA-DR positive material is localized only on endothelial and perivascular cells and in rare perineurial and endoneurial cells.

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.

Antibody response of 18 month old children 1 month and 18 months following Haemophilus influenzae type b vaccine administered singly or with DTP vaccine.

Seventy-six children (aged 17-19 months) received 10 micrograms of Haemophilus influenzae type b polyribosyl-ribitol phosphate (PRP) vaccine, diluted with either phosphate-buffered saline (PBS) or diphtheria-tetanus-pertussis (DTP) vaccine, in a single-blind randomized trial. There were few side effects when PRP was administered alone. Before vaccination 37 of 76 children (49%) had non-protective antibody levels (less than 0.

[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.

Rapid quantitative immunohistochemical assessment of human peripheral neuropathies using a monoclonal antibody against nerve growth factor receptor.

An analysis of nerve growth factor (NGF) receptor expression and density in human sural nerve biopsies was performed by immunocytochemistry with a murine monoclonal antibody against the human NGF receptor. Quantitative assessment of immunostaining density was made by histospectrophotometry on frozen sections. Although there was enhanced expression of NGF receptor within endoneurium in all patients with clinical neuropathies, expression was highest in nerves with axonal disease, consistent with the proposal that disruption of axon-Schwann cell interactions triggers the re-expression of the NGF receptor.

Ultrastructural localization of calcium binding sites on human muscle cell surface.

Calcium (Ca2+) is mainly bound to anionic phospholipids and to sialic acid at the cell surface. We studied the ultrastructural localization of these Ca2+ binding sites in normal human muscle fibers, using Polymyxin B as a marker for anionic phospholipids and the lectin Limulus Polyphemus as a probe for sialic acid. We found that anionic phospholipids have a patchy distribution along the muscle sarcolemma, with a preferential localization at the I band level and at the junction between the I and A band.

Anti-myelin-associated glycoprotein IgM antibody titers in neuropathy associated with macroglobulinemia.

Twenty-seven patients with neuropathy and IgM monoclonal gammopathy were tested for antigen specificity of the M-protein and for anti-myelin-associated glycoprotein (MAG) IgM levels by immunoblot. In 16 patients (59.2%) the M-protein reacted with MAG and with cross-reactive glycoconjugates.

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.

Normal muscle mitochondrial function in Ramsay-Hunt syndrome.

Mitochondrial encephalomyopathies may display clinical features similar to Ramsay-Hunt syndrome (RHS). We studied muscles mitochondrial function in 2 patients with RHS. Histochemical and ultrastructural studies of muscle biopsies and biochemical analysis of muscle mitochondrial enzymes were normal.

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.

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.

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.

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.

Peripheral neuropathy in macroglobulinemia: incidence and antigen-specificity of M proteins.

Peripheral neuropathy was found in 12 (46%) of 26 patients with macroglobulinemia. The neuropathy was subclinical in two. Anti-myelin-associated glycoprotein (MAG) activity was found in six (50%) patients with neuropathy.

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.