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Biomedical subjects

G Piccolo

Publications and source records attributed to G Piccolo.

At least 73 records · Page 4Linked to original sources
PubMed1991

Biological markers of oxidative stress in mitochondrial myopathies with progressive external ophthalmoplegia.

According to experimental models suggesting that overproduction of oxygen free-radicals may occur when the electron transport in the respiratory chain is impaired, we searched for in vivo biological markers of oxidative stress in 11 patients affected by histologically proven mitochondrial myopathy with progressive external ophthalmoplegia (PEO) and partial cytochrome c oxidase deficiency in muscle fibres. Six of the patients carried large-scale deletions of mitochondrial DNA. Biochemical assays included the determination of plasma and erythrocyte reduced glutathione (GSH) concentration, plasma malondialdehyde, fluorescent adducts of aldehydes with plasma proteins, and serum level of lipid peroxides. In patients with PEO the mean values of lipid peroxides and of the fluorescent adducts of aldehydes with plasma proteins were significantly higher with respect to normal controls, while the mean values of plasma and erythrocyte GSH concentration were significantly lower. The reported data indicate an increase of lipid peroxidation indexes along with the reduction of one of the most important antioxidant systems and suggest the hypothesis that overproduction of reduced oxygen species might be an adjunctive cause of cell damage in mitochondrial myopathies and encephalomyopathies associated with defects of oxidative phosphorylation.

Adult↗
PubMed1991

Prognosis of myasthenia gravis: a multicenter follow-up study of 844 patients.

The prognosis of myasthenia gravis (MG) was assessed retrospectively using life-table analysis in 844 patients followed up for a mean period of 5 years in 3 major Italian centers. The chance of achieving at least a 1-year remission after treatment withdrawal (complete remission) was assessed as a specific end-point in the whole population and in selected subgroups with reference to the principal prognostic variables. The cumulative probability of complete remission was 1% by 1 year, 8% by 3 years, 13% by 5 years, and 21% by 10 years. The only variables correlated to the chance of complete remission were younger age at onset of MG, lower severity of symptoms at onset and nadir, and shorter disease duration at diagnosis. In addition, thymectomy and early surgery seemed to influence the chance of remission. Other factors (including the presence of thymoma) did not significantly influence the outcome of the disease.

Adult↗
PubMed1991

Effectiveness of steroid treatment in myasthenia gravis: a retrospective study.

The records of 142 patients with generalized autoimmune myasthenia gravis who had been treated with steroids as the single immunosuppressive agent, collected at regular intervals, were employed for a retrospective evaluation. The effectiveness of treatment was assessed after 24 months; the data from the 6th and 12th months were also considered. After 24 months, 63.4% of the whole sample had improved (33.8% were in clinical or pharmacological remission); 13.4% were unchanged or had worsened and 22.3% had moved to a different immunosuppressive treatment. The rate of positive outcome was higher in patients over the age of 40 at disease onset.

Adolescent↗
PubMed1991

Treatment of myasthenia gravis with high-dose intravenous immunoglobulin.

We treated 37 patients affected by autoimmune generalized myasthenia gravis (MG) with high-dose intravenous gammaglobulin (HDIVIg), 400 mg/kg per day on 5 consecutive days. A one-degree improvement of Oosterhuis global clinical classification of myasthenic severity (OGCCMS), the disappearance of bulbar involvement or both were recorded 12 days after the beginning of the treatment in 70.3% of the patients and persisted up to 60 days in 58.7%. A two-degree improvement of OGCCMS was recorded in 54.1% of the patients and it was maintained up to 60 days in 37.8%. The percentage of improvement did not significantly differ between patients entering the treatment in a long-standing, drug-refractory stationary phase of the illness (n = 26) and patients who received HDIVIg in an acute phase of MG (n = 11). None of the patients experienced side effects. Our data indicates that HDIVIg is an interesting, virtually riskless therapeutic choice for MG patients, and allows the planning of a controlled trial versus plasma-exchange.

Adolescent↗
PubMed1991

Multimodal evoked potentials in progressive external ophthalmoplegia with mitochondrial myopathy.

Multimodal evoked potentials were studied in 13 patients affected by progressive external ophthalmoplegia with histologically proven mitochondrial myopathy. Progressive external ophthalmoplegia occurred with craniosomatic spreading in all the patients and with a varying degree of nervous and/or other system involvement in most of them. In all but one of the subjects, at least one evoked potential modality was abnormal; 11 of them demonstrated an abnormal visual evoked potential, but this finding might have been influenced by concurrent retinal dysfunction. Abnormalities in brainstem auditory evoked potentials and/or somatosensory evoked potentials, revealing an impairment of central sensory pathways, were detected in 7 subjects, 5 of whom lacked clinical evidence of central nervous system involvement. Thus, evoked potentials represent an useful tool for the detection of subclinical central nervous system involvement in patients affected by progressive external ophthalmoplegia with mitochondrial myopathy.

Adult↗
PubMed1991

Respiratory patterns during sleep in mitochondrial myopathies with ophthalmoplegia.

Nocturnal polygraphic recordings (electroencephalography, electro-oculography, submental and intercostal muscle electromyography, electrocardiography, respiration by thoracic strain gauges and oronasal thermistors) with continuous monitoring of arterial oxyhemoglobin saturation by pulse oximeter were performed in 8 patients with ophthalmoplegia plus. All patients except 1 had normal blood gas values and normal lung volumes associated with a diminished ventilatory response to inhaled CO2 during wakefulness. Four patients showed pathological sleep-related breathing patterns consisting of sleep apneic polygraphic tracings mainly of the central type or of REM-related hypoventilation episodes. It is suggested that these disorders in patients with ophthalmoplegia plus may have a central origin and be related to the underlying metabolic disturbance.

Adult↗
PubMed1991

Rapid detection of the A----G(8344) mutation of mtDNA in Italian families with myoclonus epilepsy and ragged-red fibers (MERRF).

We devised a rapid PCR-based method to screen for an A----G transition at nucleotide 8344 of the human mitochondrial tRNA(Lys) gene, which was recently reported, by Shoffner and co-workers, to be associated with myoclonus epilepsy and ragged-red fibers (MERRF), a maternally transmitted mitochondrial encephalomyopathy (Shoffner et al. 1990). We confirmed this association in five of seven Italian MERRF pedigrees. The mutation was specific for the MERRF trait, because it was never found in mtDNA of non-MERRF individuals, including 14 normal and 110 diseased controls. Our study corroborates the idea that the A----G(8344) mutation is the most frequent and widespread genetic cause of MERRF.

Base Sequence↗
PubMed1990

Purification of immunomodulatory factors in human peripheral blood leukocytes.

Procedure is described for purifying low-molecular-weight factors with antigen-aspecific properties from a dialysate of human leukocyte extract. It includes gel chromatography on Sephadex G-25 and G-15, ion-exchange chromatography, reversed-phase high-performance liquid chromatography (HPLC) on a C18 hydrophobic column and gel permeation HPLC. The immunosuppressive factor (mol.wt. 800-1000) was purified to near homogeneity. It is probably of peptidic nature, although it is pronase resistant. The enhancer factor (mol.wt. 300-600) is eluted from chromatographic columns together with a hypoxanthine-like substance. Nevertheless, the biological activity cannot be attributed to the purine derivative. Identification of this amplifier activity is still lacking.

Adjuvants, Immunologic↗
PubMed1990

Devic's neuromyelitis optica: long-term follow-up and serial CSF findings in two cases.

Sixteen cerebrospinal fluid (CSF) specimens serially obtained during long-term follow-up of two patients with Devic's neuromyelitis optica (DNO) were compared with 65 CSF samples from patients with multiple sclerosis (MS). By statistical analysis, the CSF profile in DNO was found to differ from that observed in MS, mainly showing pleocytosis, blood-brain barrier damage, and absence of persistent immunoglobulin G synthesis within the central nervous system. Oligoclonal bands, detected with isoelectric focusing, were present in CSF of 92% of the patients with MS, and in three CSF specimens from one patient with DNO during the first 6 months after disease onset. The bands disappeared in two subsequent samples. This finding has never been described in MS. One patient with DNO had an apparent chronic-relapsing course probably due to steroid dependence. The clinical and CSF features of our cases favour the nosographic independence of DNO and MS.

Adult↗
PubMed1990

A multicentre follow-up study of 1152 patients with myasthenia gravis in Italy.

A multicentre retrospective study was carried out on the characteristics and course of myasthenia gravis (MG) in Italy. Data from 1152 patients, fairly representative of the myasthenic population seeking medical advice, were analysed for diagnostic criteria, clinical aspects and therapeutic approaches. Mean follow-up was 4.9 years. The disease was correctly diagnosed within 2 years of the onset in 80% of cases. Onset of symptoms peaked in the second and third decade in females and fell between 20 and 59 years in males. At first observation 87% of the patients had generalized MG. Maximal worsening was observed within 3 years in 77% of patients. At the last follow-up, 35% of cases were symptom-free (pharmacological remission 24%, remission without treatment 11%). The more severe the disease at the first observation and at the maximal worsening of symptoms, the lower was the proportion of remissions. Steroids were given in 54% and immunosuppressants in 18%. Thymectomy was performed in 72%, mostly in women, younger than age 40, and with generalized MG. Thymectomy seemed to improve the course of the disease, mostly in patients operated on shortly after diagnosis and those with generalized mild-to-moderate disease and with a normally involuted thymus. MG was lethal in 4% of patients, principally men, older than 40, in grade 3 or worse at first observation, with a short history of disease, and with thymona.

Adolescent↗
PubMed1990

Autoimmune myastenia gravis with thymoma following the spontaneous remission of stiff-man syndrome.

A patient who developed generalized autoimmune myasthenia gravis six years after the spontaneous remission of a stiff-man syndrome is described. He also suffered from chronic active hepatitis and had radiological evidence of a thymoma. He did not have diabetes mellitus. Besides anti-nicotinic acetylcholine receptor antibodies, anti-nuclear, anti-DNA, anti-mitochondrial and anti-skeletal muscle antibodies were found in his serum, while islet-cell antibodies were absent. Immunocytochemistry studies failed to demonstrate autoantibodies to GABA-ergic nerve terminals, although an aspecific neuronal immunostaining was observed. The clinical and immunological features of this case support the hypothesis of a dysimmune pathogenesis of SMS, also in cases not associated with autoimmunity to GABA-ergic nerve terminals. Furthermore, a relationship between thymoma and the neurological syndromes discussed could be considered.

Central Nervous System Diseases↗
PubMed1990

Isoelectric focusing herpes simplex virus-gB overlay study in brainstem encephalitis.

We report a case of herpetic brainstem encephalitis (HBE) retrospectively diagnosed in adult patient. Conventional immunovirological studies failed to disclose the etiology of this patient's affection. An isoelectric focusing-antigen overlay (IEF-O) technique showed that the target of one of the four cerebrospinal fluid oligoclonal bands was herpes simplex virus (HSV)-1 glycoprotein B, indicating a specific anti-HSV immunoresponse restricted to the CNS. IEF-O may represent a useful support for in vivo diagnosis of HBE.

Adult↗
PubMed1989

Specificity of calcium channel autoantibodies in Lambert-Eaton myasthenic syndrome.

Autoantibodies that interfere with neurotransmitter release by affecting the function of voltage-operated calcium channels (VOCCs) have been found in patients with Lambert-Eaton myasthenic syndrome (LES). To find out the nature of the antigen to which these autoantibodies bind, tests were done with omega-conotoxin, which blocks some types of VOCCs. LES antibodies were able to immunoprecipitate VOCCs prepared from the human neuronal cell line IMR32 which were pre-labelled with the specific VOCC ligand omega-conotoxin. LES autoantibodies are also able to specifically down-regulate the expression of VOCCs in IMR32 cells. A new radioimmunoassay for the quantitative detection of LES antibodies was developed and found to be of value in distinguishing LES patients from patients with myasthenia gravis and some other neurological disorders.

Autoantibodies↗
PubMed1989

Tumor necrosis factor in serum and cerebrospinal fluid of patients with multiple sclerosis.

We measured levels of alpha-tumor necrosis factor (alpha-TNF) in cerebrospinal fluid and serum samples from 50 drug-free patients with multiple sclerosis, 25 patients with other neurological diseases, 27 patients with non-neurological diseases, and 10 normal subjects. The most elevated levels of alpha-TNF were found in patients with inflammatory or autoimmune diseases. Comparable serum levels of alpha-TNF were detected in normal control subjects, patients with multiple sclerosis, and patients with degenerative neurological diseases. In patients with multiple sclerosis, alpha-TNF levels were also unrelated to time elapsed between the occurrence of clinical exacerbation and the time of sample collection. Only 3 patients with chronic progressive multiple sclerosis had detectable alpha-TNF in the cerebrospinal fluid. Our data do not support a role for elevated levels of circulating alpha-TNF in the maintenance of the disease. However, we cannot rule out the possibility that a transient elevation of alpha-TNF triggers the cellular events leading to demyelination in multiple sclerosis.

Adolescent↗
PubMed1989

Normal insulin receptors in mitochondrial myopathies with ophthalmoplegia.

Seven patients with histologically proven mitochondrial myopathy with ophthalmoplegia (OMM), 6 of them nondiabetic, 1 affected by diabetes mellitus (DM), were submitted to a study of glucose tolerance and of insulin receptors on peripheral mononuclear cells and cultured skin fibroblasts. The diabetic patient, who had the typical features of the Kearns-Sayre syndrome (KSS) and deleted muscle mitochondrial DNA (mtDNA) presented a low insulin secretion rate under physiological stimuli (intravenous glucose and glucagon) whereas the insulin receptor parameters were found normal. The other patients showed a normal glucose tolerance and normal insulin receptors. Our data support the hypothesis that insulin receptors are not involved in the pathogenesis of DM associated with mitochondrial encephalomyopathies, in contrast to other neuromuscular inherited disorders. The clinical and biological features of DM presented by our KSS patient show normal insulin receptor parameters in spite of a defective insulin secretion, possibly depending on mitochondrial dysfunction.

Adult↗
PubMed1989

[Buprenorphine in balanced anesthesia].

Buprenorphine was administered for the balanced general anaesthesia in 300 patients during several operations. The results obtained, the good features of analgesia, morphine-like, the absence of cardiovascular and respiratory side effects are presented.

Adolescent↗