R. L. Friede

Anti-macrophage CR3 antibody blocks myelin phagocytosis by macrophages in vitro

SummaryMyelin phagocytosis in Wallerian degeneration of peripheral nerves depends on invasion of nerves by non-resident macrophages. The present study was done to clarify the role of the macrophage complement receptor type 3 (CR3) in myelin removal. Myelin phagocytic capacity of invading macrophages was abolished by treatment of cultured nerves and macrophages with anti-CR3 antibody or by serum complement depletion with cobra venom factor. This indicates that myelin phagocytosis is mediated by the macrophage CR3.

Myo-, neuro-, gastrointestinal encephalopathy (MNGIE syndrome) due to partial deficiency of cytochrome-c-oxidase

SummaryA 42-year-old woman had a 10-year history of external ophthalmoplegia, malabsorption resulting in chronic malnutrition, muscle atrophy and polyneuropathy. Computer tomography revealed hypodensity of her cerebral white matter. A metabolic disturbance consisted of lactic acidosis after moderate glucose loads with increased excretion of hydroxybutyric and fumaric acids. Post-mortem studies revealed gastrointestinal scleroderma as the morphological manifestation of her malabsorption syndrome, ocular and skeletal myopathy with ragged red fibers, peripheral neuropathy, vascular abnormalities of meningeal and peripheral nerve vessels. Biochemical examination of the liver and muscle tissues revealed a partial defect of cytochrome-c-oxidase (complex IV of the respiratory chain). This mitochondrial multisystem disorder may represent a separate entity to be classified between the spectrum of myoencephalopathies and oculo-gastrointestinal muscular dystrophy.

Ventricular diverticles with localized dysgenesis of the temporal lobe in cloverleaf skull anomaly

SummaryAn early fetal case of cloverleaf skull anomaly associated with thanatophoric chondrodystrophy is described. Localized ventricular diverticles are a peculiar finding. In addition there are previously described malformations limited to the temporal lobes and comprising plump gyri with abnormal deep sulci, thick periventricular heterotopias, dysgenesis of the parahippocampal gyrus, agenesis of the Ammons horn, and small micropolygyria. The skull deformity is not dependent on hydrocephalus, demonstrating inconsistencies in previous pathogenetic concepts.

Focal intracerebral accumulation of a novel type of amyloid protein

SummaryThe brain of a 60-year-old patient with bronchial carcinoma presented a focal amyloid deposit in the white matter associated with myelin and axonal destruction. An additional lesion was found in the basal ganglia. This silent focal intracerebral accumulation of amyloid substance may be a prestadium of a “cerebral amyloidoma”. The histochemical chemical and immunohistochemical analysis of the accumulated amyloid indicated that it may belong to a novel type of amyloid.

Computer editing of morphometric data on nerve fibers: an improved computer program

SummaryA short guide is given for the planning of nerve fiber morphometry using computer-assisted methods. A new computer program is introduced which allows, among other factors, correction for myelin sheath shrinkage. If myelin shrinkage is not corrected for, there will be false high values for axon caliber and false low values for sheath thickness. The magnitude of the skew produced by this factor is shown on hand from computer editing.

Unilateral hydrocephalus from early developmental occlusion of one foramen of Monro

SummaryUnilateral hydrocephalus due to occlusion of one foramen of Monro was found incidentally at necropsy in a 52-year-old man. There was no evidence of a postinflammatory or neoplastic origin of the occlusion. Backward tilting of the diencephalon, asymmetric insertion of the septum pellucidum, lateral tilting of the fornices, and deformation of the hippocampal formation indicated an early developmental origin of the lesion.

The angiogenesis of micrencephalic rat brains caused by methylazoxymethanol acetate

SummaryThe intracortical angioarchitecture of normal and micrencephalic rat brains was examined. The neuroblast migration was disturbed by injection of the neurotoxin methylazoxymethanol acetate, administered on day E14. The internal vascularization of the malformed cortex showed severe damage to the layered distribution of vascular trunks in contrast to controls. A pathological course and marked variability in the density of the radial vessels were seen in the parieto-occipital areas, in which the neuroblast migration was most severely affected. These observations show the decisive role of neuroblast migration and maturation in the development of the cortical angioarchitecture.

Dandy-Walker syndrome with atresia of the fourth ventricle and multiple rhombencephalic malformations

SummaryA case of Dandy-Walker syndrome associated with multiple maldevelopmental lesions of the brain stem and cerebellum is presented. The additional malformations include hypoplasia of both cerebellar hemispheres with multiple foci of cortical dysplasias, rostral dilatation of the fourth ventricle and atresia in its caudal part, hypoplasia of the basis pontis, displacement and dysplasia of several nuclear groups of the medulla oblongata, including subtotal aplasia of the inferior olivar complex, and incomplete decussation of the pyramidal tracts.These lesions implicate a hindrance of neuroblastic proliferation and migration from rhombencephalic cytogenetic zones of the entire alar plate with peristent anterior membranous area.

Experimental production of leptomeningeal heterotopias from dissociated fetal tissue.

SummarySubarachnoid heterotopias were produced experimentally in rats by intracisternal injection of dissociated fetal brain tissue. Heterotopias contained neurons and glial tissue and also mesodermal tissue including striated skeletal muscle. The data show that particles of disintegrated germinal tissue can survive, redistribute, settle and mature within the CSF spaces.

A quantitative assessment of myelin sheaths in the peripheral nerves of dystrophic, quaking, and trembler mutants

SummaryIf myelin sheaths are relatively thin for axon caliber, this is generally taken as a sign of insufficient myelin formation. However, recent studies have shown that sheath thickness relates not only to axon caliber; the relative length of the internode is also important. Foreshortened internodes have slightly thinner sheaths than long internodes of the same fiber caliber (Friede and Bischhausen 1982).In the present study we compared sheath thickness with internode geometry in the sciatic fibers of three murine mutants, the Dystrophic, Quaking and Trembler mice, using a new computer-assisted method. A quantitative correspondence was found between abnormally thin sheaths and internode foreshortening. The magnitude of the changes was the same as that found previously in normal and regenerated fiber populations. The data show that the geometric proportions of internodes cannot be ignored when assessing sheath thickness, and they also shed some new light on the mechanisms which produce abnormally thin sheaths.