Abstracts

Abstract

ABSTRACT In Duchenne muscular dystrophy (DMD), morphological abnormalities in freeze fractured plasma membranes of skeletal muscle cells (decrease of intramembraneous particles and orthogonal particle arrays) led to the hypothesis that a defect of the plasmalemma is correlated with a pathological influx of calcium into non‐necrotic muscle cells in early stages of the disease. This is shown light microscopically in 40 Duchenne patients by Morin‐ and Alizarin‐red‐stains and electron microscopically by the KPA (potassium pyroantimonate)‐calcium precipitation method. KPA‐calcium precipitation is observed mainly in the mitochondria, in the nuclei, moderately between the myofibrils and subsarcolemmally (delta regions). Using atomic absorption spectrometry (Dr. Frey, Physiologisches Institut, Universität Freiburg) we were able to confirm these histopathological results. There is a highly significant increase in muscular calcium accompanied by a reciprocal decrease in magnesium: the ratio Mg++/Ca++ decreases from 12.85 (healthy control muscle) to 2.16 (DMD). In contrast to DMD muscle (mean % of Ca++‐positive fibers: 7%) cellular calcium accumulation is rare in autosomal recessive and Becker‐Kiener muscular dystrophies or other myopathies, and the plasma membrane structure in freeze fracture preparation is also significantly different from DMD. In 4 of 8 investigated male fetuses at risk for DMD, similar results could be obtained with regard to the calcium accumulation light and electron microscopically, as in affected DMD patients. In freeze fracture, a high% of plasma membranes of these positive fetuses show a decrease of intramembraneous particles.The results in early stages of DMD and in fetuses at risk for DMD support the hypothesis of a basic abnormality of the plasmalemma correlated with a pathological influx of calcium into the muscle cell together with a depletion of muscle magnesium. This might account for a mitochondrial decompensation and various metabolic disturbances, finally leading to cell necrosis. Calcium antagonists may have therapeutic value in DMD. activity in the pathognomonic nerve fibers of the lamina propria could be demonstrated in HD. The tubulin antiserum stained neuronal structures such as the cytoplasm, the axon cone and axons preferentially within the deep muscle layers of the gut wall and the submucosal plexus. Neither endocrine mucosal cells nor aberrant fibers in the lamina propria in HD and VIF showed tubulin‐IR. This property could prove the tubulin antibody to be an appropriate tool in detecting neurons of the deep plexus suitable for defining the borderline of the resection of the aganglionic segment in the surgical treatment of HD. A similar staining pattern was found in MBP‐IR, demonstrating myelinated fibers and intestinal glial cells mainly within the deep plexus, and this serum could attribute to further differentiation of neuronal intestinal dysplasia syndromes with respect to Schwann cell hyperplasia. In the case of VIF, numerous normal reacting ganglionic and glial cells could be demonstrated in the submucous and myenteric plexus, but pathologically as in HD there could be found aberrant VIPergic‐cholinergic fibers in the mucosal lamina propria.Joint Meeting of the German and Scandinavian Neuropathologists Turku, FinlandEnzymhistochemistry in normal pelvic sphinctersEffects of vitamin E deficiency on skeletal muscle in the ratMixed nemaline‐core myopathy with adult‐onsetNerve fiber lesions and the consequences interpreted by enzyme histochemistryExperimental thalidomide neuropathy: the morphological correlate of reduced conduction velocityUltrastructural and morphometric findings in sural nerves of children with autosomal recessive/sporadic hereditary motor and sensory neuropathy type IImmunocytochemical demonstration of human immunoglobulins in the peripheral nerves after systemic passive transfer to mice and monkeysImmunocytochemical demonstration of immunoglobulins in sural nerve biopsiesExperimental paramyxovirus infections in the mouse brainCoronavirus‐induced demyelinating encephalomyelitis in rats: europathological and immunological studiesValidity of clinical diagnosis in senile dementia: prospective clinicopathological studyNeuronal uptake of extravasated macromolecules of horseradish peroxidase and their transport by axons to other regions from a focal vasogenic cerebral edemaThe presence of small intensely fluorescent (SIF) cells in the leptomeningesMonoclonal antibodies to intermediate filaments in neuropathologyStructural requirements for receptor‐mediated endocytosis of glycoproteins in nerve cell cultureNeuron‐associated peptides in human colonic biopsiesComparative morphometric studies of the post‐natal development of peripheral nerves