Biomedical subjects
Publications and source records attributed to M Comola.
We describe the diffusion-weighted MRI findings and follow-up in a case of autopsy-proven Creutzfeldt-Jakob disease that revealed abnormal hyperintensity in the cortex and basal ganglia.
We describe a patient affected by the Lambert-Eaton myasthenic syndrome, sensory motor axonal neuropathy and epidermoid carcinoma of the lung. Serum autoantibodies to voltage-operated calcium channels were detected. After lobectomy, voltage-operated calcium channel-related structures were demonstrated in the patient's tumor. By immunocytochemistry, the patient's IgG reacted with neural structures and particularly with intermediate filaments. We think that these autoantibodies may be implicated in the pathogenesis of the neurological symptomatology.
Although anatomical abnormalities of the upper airway have been recorded in some patients with obstructive sleep apnoea (OSA), a muscle tone dysregulation also seems to have an important role in this disorder. Since habitual snoring is the initial stage of OSA, the structural characteristics of upper airway muscles (medium pharyngeal constrictor muscle [MPCM]) from 13 men (9 non-snorers and 4 habitual snorers) were studied. MPCM fibre structure in non-snorers was broadly similar to that in normal limb muscles, with the exception that fibre diameters were smaller for all fibre types. Compared with limb muscles, MPCM had a smaller proportion of type IIb fibres and a higher proportion of types I and IIa fibres. MPCM in habitual snorers had an abnormal distribution of fibre types (low percentage of type I and type IIb fibres and high percentage of type IIa fibres) compared with non-snorers (p less than 0.001) and the type IIa fibres were hypertrophic. No myopathic or neurogenic changes were seen. Two possible hypotheses explain the abnormal distribution of fibre types in snorers. First, a constitutionally determined reduction of slow alpha-motor neurons induces an adaptive transformation of type IIb to type IIa fibres and a hypertrophy of type IIa fibres; or, second, motor neurons change their patterns of discharge and, hence, of activation, and modify fibre-type distribution of MPCM as an adaptation to the anatomical characteristic of upper airway and habitual snoring.
We describe three patients with chronic progressive polyneuropathy associated with IgA monoclonal gammopathy. Two patients had a prominent sensory neuropathy and one had a prominent motor neuropathy. Sural nerve biopsies showed axonal degeneration in all cases. In immunocytochemical studies patients' IgG immunostained axons. By Western immunoblot a band of IgG reactivity with an axonal protein of 66 kDa was found. No band of IgA and IgM were found. We suggest the possibility that the IgA monoclonal protein may act as a stimulating factor of preexisting B cell clones eliciting an immune reaction against nerve antigens.
Two siblings with Lafora disease (LD) are described: one with epilepsy, myoclonus, EEG abnormalities, severe dementia and many Lafora bodies (LBs) in muscle and skin tissue; the other with myoclonus, epilepsy, EEG abnormalities and LBs in muscle and in skin tissue, without dementia. The findings suggest that the diagnosis of LD by skin and muscular biopsy is possible in the early stage of the disease, when there are myoclonic epilepsy and EEG abnormalities, before the onset of dementia.
The aim of our study was to evaluate in the rat the ability of a polytetrafluoroethylene microprosthesis (PTFE), to guide the peripheral nerve regeneration between the two extremities of a transected sciatic nerve. In 15 adult male Wistar rats, weighing 200 g, a segment of the right sciatic nerve was resected, leaving a gap of about 1 cm, bridged with microprosthesis, using our original microsurgical technique. Neurophysiological evaluations were performed at 6 and 9 months post-operatively to study the distal motor latency either in the right sciatic nerve or in the unoperated control side. In all the rats myoelectrical responses with an increased latency of the operated side were produced from the interosseous muscle of the foot. The animals were sacrificed 9 months post surgery. Histological sections at the level of the graft were done in all the rats, and in 10 animals biopsies of the tibialis anterior muscle (TA) of each side were performed. An active process of axonal regeneration was documented inside the graft, with no infiltration of nerve fibers through the wall of the prosthesis. A connective fibrous reaction was present around the external wall of the graft. Muscle biopsies showed definite signs of muscle reinnervation, with residual features of variable degree of denervation. These findings stress and confirm the ability of the PTFE graft to allow effective regeneration in a peripheral nerve gap in the rat.
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Neuropathological lesions characteristic of Alzheimer's disease (AD) are found in all the brains of patients with trisomy 21 who die after age 40 years. However, clinical signs of AD are much less frequent in these patients. Previous studies indicate prevalence figures ranging from 15% to 51% of adult patients. We report here on the prevalence rate of dementia in a population of adult patients with trisomy 21 with mild retardation living at home. For all these patients accurate and reliable anamnestic data could be obtained from parents and caregivers. All underwent neurological examination, cognitive testing, and, if necessary, further bioimaging and neurophysiological studies. Dementia was diagnosed according to clinical NINCDS/ADRDA criteria slightly modified. Dementia was found in 9 of 50 (18%) patients age 20-52 years, but its prevalence increased from 0 in the age group 20-29, to 33% in the age group 30-39, and to 55% in the age group 40-52. All the demented patients had signs of brain atrophy on CT scans and slow EEGs. Dementia is an important problem for patients with trisomy 21 older than age 30 years.
About 30-40% of AIDS patients present CNS and/or PNS involvement, due to direct action of HIV virus or opportunistic infections. Nervous system involvement in the HIV correlated syndromes is not a rare occurrence; nevertheless no studies about prognosis of AIDS related syndromes have been published yet. We tested 38 HIV positive patients for the assessment of neurological complications by means of clinical and instrumental evaluations: multimodal evoked potentials, EMG/ENG studies, nerve and muscle biopsy. At the baseline evaluation, 26/38 patients had neurological complications: 14 of CNS, 9 of PNS, 3 of both CNS and PNS. At follow-up, 16/37 patients had developed AIDS and 10/16 patients with AIDS died. Of these 16 patients, 14 had clinical and neurophysiological alterations at the baseline evaluation. Our results suggest that the presence of clinical and/or neurophysiological nervous system involvement in patients with HIV-related syndromes constitutes a negative prognostic factor for developing AIDS.
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We used an indirect immunoperoxidase technique (Avidin-Biotin system) to study the sera of patients with "clinically probable" Alzheimer's disease (AD) and with Down's Syndrome (DS), compared with age-matched controls. Diluted sera were incubated with paraffin sections of hippocampus, frontal, temporal, and parieto-occipital lobes from normal human brains. Biotinylated anti-human goat gamma-globulins were used as secondary antisera. A significantly greater percentage of neurons were immunostained in all the brain regions (frontal, temporal, and parieto-occipital lobes and hippocampus) incubated with sera of AD patients than with sera of DS patients or of controls. This indicates that AD patients have an excess of circulating neuron-binding antibodies (NBAs), mainly reacting with cytoplasmic structures. NBAs could be either the cause or the result of the cerebral lesion found in AD. This study is not able to answer this question, but some previous data from our own and other laboratories suggest that NBAs have a role in the pathogenesis of AD lesions. Since we found no increase of NBAs in DS patients, the brain lesions in DS appear to have a different pathogenesis.
A 56 year old man with acute sensory-motor polyneuropathy associated with mycosis fungoides is described. EMG studies showed diffuse signs of muscle denervation. A skin biopsy specimen showed a lymphocyte infiltration in the dermis, composed of mycosis cells characterised by deep invaginations of the nuclear membrane, and small Pautrier's microabscesses in the epidermis. Sural nerve biopsy revealed endoneurial fibrosis, a decreased number of myelinated fibres and acute axonal degeneration.
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Muscle biopsies from 56 patients with polymyositis (PM), juvenile dermatomyositis (JDM) and adult dermatomyositis (ADM) were investigated using a range of quantitative histological techniques. The objective was to present data on the extent and distribution of muscle fibre degeneration in these patients and to determine whether these data were compatible with postulated mechanisms of fibre injury. Atrophy of one or more of the major fibre types was found in 45/56 biopsies but there was no evidence that particular patterns of type-specific atrophy were characteristic of any individual disease group. However, selective atrophy and/or necrosis of perifascicular fibres was much more common in JDM patients than in ADM or PM groups. In virtually all biopsies where abnormalities of the microvasculature were apparent (7/8 JDM biopsies, 4/13 ADM biopsies and 5/33 PM biopsies) the distribution of acute muscle necrosis was found to be non-random (clustered). However, a substantial proportion of biopsies in the PM group showed clustering of necrotic fibres in the absence of evidence of vascular involvement. This finding suggests that non-random targetting of muscle fibres by effector cells may occur.
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The diagnostic value of nerve and muscle biopsy in detecting several neurological diseases is discussed. A bioptic technique for current surgical practice is proposed.
Acute myopathy in conditions associated with endogenous or drug-induced potassium loss has been reported. We describe six patients with potassium depletion myopathy (P-DM). The clinical picture included flaccid muscle weakness without sensory loss, myalgia, polyuria, and polydipsia. All the cases had markedly increased serum creatine kinase (CK) levels. The most consistent pathological characteristics were phagocytosis of degenerating muscle fibers plus fiber regeneration. Atrophy of type 2 fibers was observed. Vacuoles and vesicular elements originating from T-tubules were also encountered. The clinical manifestations and morphological changes had reversed after potassium repletion. Both constriction of vascular smooth muscle and cellular energy failure may be pathogenetic factors in P-DM.
The case of a 34-years-old man is described with a progressive myopathy characterized by limb weakness and atrophy, involvement of facial, masticatory and extraocular muscles. The prominent features of the muscle biopsy were the presence of centrally located nuclei in most fibers. There was also an atrophy and predominance of type I fibers. Both clinical and morphological features were consistent with the diagnosis of centronuclear myopathy. Electron microscopic studies showed the presence of mitochondria with paracrystalline inclusions near the centralized nuclei but not in the subsarcolemmal position. This hitherto unreported feature led the authors to re-evaluate the hypothesis on the pathogenesis and the nosological classification of this myopathy.