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Biomedical subjects

H Lassmann

Publications and source records attributed to H Lassmann.

At least 271 records · Page 15Linked to original sources
PubMed1981

Neurological disease in a child with carnosinase deficiency.

Carnosinase deficiency presented as a progressive neurological problem with sensory polyneuropathy in a 12-year-old male. Carnosinuria was present, even on a meat-free diet, although carnosinemia was not observed. An increased amount of unmetabolized carnosine was found in the urine after a carnosine load. Serum and tissue (liver and nerve) from the patient showed deficient carnosinase activity (Fleisher et al. 1978, 1980). Morphometric and fine structural studies on the nerve and skin biopsies are presented, as is a review of the literature on carnosinase deficiency in mentally retarded patients.

Carnosine↗
PubMed1981

Myelin proteins, glycoproteins, and myelin-related enzymes in experimental demyelination of the rabbit optic nerve: sequence of events.

Wallerian degeneration of the rabbit optic nerve was investigated by the technique of retinal ablation which precludes edema, hemorrhage, or macrophage infiltration. After 8 days of degeneration, marked degradation of axons and some myelin abnormalities appeared in the optic nerve, optic chiasma, and optic tract. Myelin lesions were maximal 32 days after retinal destruction. The amount of material stained with a myelin dye decreased drastically between 32 and 90 days after the operation. Biochemical parameters gave the following sequence of events. The concentration of the major periodic acid--Schiff staining glycoproteins was decreased after 2 days, and 6 days later the presence of cholesterol esters was detected in the optic tissue. After 16 days of Wallerian degeneration, the specific activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase not associated with myelin decreased, indicating a possible de-differentiation of oligodendrocytes. Degradation of myelin basic protein became significant at 32 days and the amount of myelin isolated decreased later. The loss of myelin basic protein coincided with a reduction of myelin periodicity as measured in purified fractions by electron microscopy. These results show that secondary myelin destruction in the absence of edema, hemorrhage, or macrophages is a very slow process, and in this situation myelin undergoes a selective and sequential loss of its constituents.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1981

Immunologic studies of chronic relapsing EAE in guinea pigs: similarities to multiple sclerosis.

IgG/albumin ratios and presence of oligoclonal bands were studied in neutral pH brain extracts and sera of guinea pigs with chronic relapsing experimental allergic encephalomyelitis (R-EAE). The ratios were found to be significantly increased in central nervous system extracts of animals sacrificed during the first relapse and late stages of the disease relative to those of controls and of animals with acute EAE. These results are consistent with an intracerebral synthesis of IgG found in patients with multiple sclerosis (MS). When the immunofixation (after isoelectric-focusing) patterns of brain extracts and CSF from R-EAE animals were compared with those of controls, R-EAE animals showed distinct oligoclonal IgG bands in the pH region of 7.0 to 9.3, in contrast to diffuse patterns seen in controls. The finding of oligoclonal IgG in brain extracts of these animals further supports the usefulness of R-EAE as an experimental model for MS.

Albumins↗
PubMed1980

Chronic relapsing experimental allergic encephalomyelitis. Immunohistochemical studies.

The immunohistochemical staining of immunoglobulins (Ig), complement (C3), and fibrinogen in chronic relapsing experimental allergic encephalomyelitis lesions showed different staining patterns in the acute vs the chronic stage of the disease. In the acute stage, Ig, C3, and fibrinogen were present in the perivascular tissue of the brain and the spinal cord. In hyperacute-type lesions, the binding of Ig and C3 to the parenchyma was especially pronounced. The chronic stage of the disease was characterized by Ig-containing cells and Ig binding to white matter in actively demyelinating lesions. Linear or granular deposits of immunoglobulin and complement, reminiscent of those described in immune complex disease, were found in the choroid plexus.

Animals↗
PubMed1979

Chronic relapsing experimental allergic encephalomyelitis: effect of age at the time of sensitization on clinical course and pathology.

Experimental allergic encephalomyelitis was induced by sensitization with guinea pig spinal cord in complete Freund's adjuvant with increased content of myobacterium in Hartley guinea pigs between the first and 28th day after birth. The animals either died during acute EAE or showed chronic progressive, chronic relapsing or chronic EAE with delayed onset. In animals immunized between the 1 and 13 day after birth, predominatly ordinary and chronic progressive EAE was noted, whereas animals sensitized between the 14th and 23rd day frequently suffered from hyperacute or chronic relapsing EAE. Immunization on the 24th day led to very high mortality in acute EAE. The relation of the pathohistologic alterations to different types of human inflammatory demyelinative disease is discussed.

Age Factors↗
PubMed1979

Chronic relapsing experimental allergic encephalomyelitis: morphological sequence of myelin degradation.

Myelin degradation in chronic relapsing experimental allergic encephalomyelitis was studied using light microscopic histochemistry and electron microscopy. In the earliest stages, a large number of myelin stripping macrophages were found. The Luxol fast blue positive degradation products were then gradually transformed into PAS positive material. No sudanophilic stage of myelin degradation was found in this model. In electron microscopy, the Luxol fast blue positive material was identified as uniformly layered lipid inclusions with a periodicity of 4.0--4.5 nm. During further digestion, this material was transformed into polymorph structured material, consisting of lamellar leaflets with a diameter of 7--10 nm, curved cylindrical profiles and granular osmiophilic material.

Animals↗
PubMed1979

Chronic relapsing experimental allergic encephalomyelitis: clinicopathological comparison with multiple sclerosis.

Clinical and neuropathological observations in chronic, relapsing experimental allergic encephalomyelitis (EAE) are reported and compared with data available for multiple sclerosis (MS). Clinical, relapsing EAE was found in 95 of 119 of the strain 13 and 22 of 57 of the Hartley guinea pigs immunized. Examination of the brains and spinal cords of the guinea pigs showed a high incidence of macroscopically visible, demyelinated plaques. The topographic distribution of lesions resembled a pattern similar to that described in MS. Microscopic features of the lesions consisted of perivenous inflammation, primary demyelination, oligodendrocyte loss, and reactive gliosis. It is concluded that, with the exception of minor differences, the clinical and pathological alterations in chronic, relapsing EAE closely resemble those found in MS.

Animals↗
PubMed1979

Tactile corpuscle-like structures in a case of plexiform neurofibromatosis.

Tactile corpuscle-like structures were identified in a plexiform neurofibroma, which was localized on the right cranial hemisphere os a 16-year-old boy and had necessitated repeated surgery. These structures were studied by light and electron microscopy. The origin of their component cells is, however, still controversial. We believe to have accumulated sufficient evidence for a Schwann cell origin of these cells.

Adolescent↗
PubMed1978

Ultrastructural sequence of myelin degradation. I. Wallerian degeneration in the rat optic nerve.

The ultrastructural events in myelin degradation in the rat optic nerve following transection have been studied. Myelin debris was found in cells similar to multipotential glia cells (Vaughn and Peters, 1968) as well as in astrocytes and in few oligodendrocytes. The different types of inclusions found during myelin degradation were described in their quantitative relations. Similarities to inclusions described in adrenoleukodystrophy adn multiple sclerosis are discussed. By comparison of the ultrastructural findings with histochemical and biochemical data available a hypothetical model of myelin degradation is presented. The process starts with the degradation of digestible proteins resulting in uniformly layered lipid inclusions. Lipid degradation leads to the formation of unstructured lipid droplets and crystals. During the late stages of Wallerian degeneration numerous polymorph inclusion typed can be found, probably representing poorly digestible lipids or lipoproteins.

Animals↗
PubMed1978

Ultrastructural sequence of myelin degradation. II. Wallerian degeneration in the rat femoral nerve.

Myelin degradation in Wallerian degeneration of rat femoral nerves has been studied with the electron microscope. In the initial stages, a decrease of myelin periodicity from 115 A to 88 A was noted, followed by the transformation of the myelin structure into uniformly layered lipid inclusions. 10--14 days after nerve section, most of the inclusions found represented unstructured lipid droplets or crystals. In the later stages of degeneration, numerous pleomorphic lamellar inclusions were found, some of them resembling the structure of pi and micron-granules. Lysosomal enzyme activity was found especially in pleomorphic inclusions during the late stages of myelin degradation. Normal myelin sheaths, as well as unstructured lipid droplets and crystals, were devoid of enzyme activity. The results are compared with alterations found in Wallerian degeneration of the central nervous system.

Animals↗
PubMed1978

The relation of nervous elements to intradermal nevi. As electron microscopic study.

Intratumoral nerves of dermal nevi were investigated by electron microscopy in order to elucidate the role of neural elements in the development of these tumors. The following results were obtained: 1. Intratumoral nerves exhibit an increased cellularity, but the number of myelinated fibers is reduced. 2. Nevus cells type B and C are frequently present within nerve fascicles. 3. Unmyelinated axons were found in close relationship to nevus cells. 4. Schwann cells may show proliferations similar to early stages of neurofibroma and can be differentiated from unpigmented tumor cells by their relation to axons only. These findings indicate that identical cell populations are present within the intratumoral nerves and the tumor itself. Therefore, the theory of a neural component in the histogenesis of intradermal nevi is supported.

Adult↗
PubMed1978

The proliferation of adrenal medullary cells in newborn and adult mice. A light and electron microscopic autoradiographic study.

The proliferative activity of newborn and adult mouse adrenal medullary cells was determined with light and electron microscopic autoradiography. The H3 thymidine labelling index of 2 weeks old mice adrenal medullary cells was about 9.4% and declined to less than 1% in adult mice. In electron microscopic autoradiography labelled norepinephrine as well as epinephrine cells could be seen. Only in 1 and 2 weeks old mice some morphologically undifferentiated cells were visible. In formaldehyde induced fluorescence combined with light microscopic autoradiography the fluorescence intensities of labelled and unlabelled medullary cells were measured. On average the fluorescence intensity of labelled cells was lower than that of unlabelled cells. The differences could be explained by a higher number of autoradiographic silver grains laying on the cytoplasm of labelled cells. These results give evidence that fully differentiated adrenal medullary cells are capable of division.

Adrenal Medulla↗
PubMed1978

Demonstration of specific storage material within cutaneous nerves in metachromatic leukodystrophy.

Biopsies of clinically unaltered skin from a 5-year-old girl with metachromatic leukodystrophy were studied by light, fluorescence and analytical electron microscopy. Investigation of hematoxylin-eosin-stained sections revealed no pathologic changes, but a brown metachromatic material was found within cutaneous nerves after acetic acid cresyl violet staining of frozen sections. In semithin Epon sections small dermal nerve fascicles contained endoneural deposits, which proved to correspond with the typical prismatic, dense or Tuffstein bodies described in other organs of patients suffering from MLD. The inclusions were located mainly within Schwann cells and exhibited a bright orange fluorescence after trypaflavine-phosphotungstic acid-treatment as well as a high electron density in serial ultrathin sections. Energy dispersive X-ray microanalysis revealed a high sulfur content in the membrane bound granules. These findings demonstrate the presence of the specific storage material also within cutaneous nerves in MLD and thus suggest skin biopsies as an addiitonal and simple diagnostic acid in this disease.

Child, Preschool↗
PubMed1977

Different types of benign nerve sheath tumors. Light microscopy, electron microscopy and autoradiography.

In a light-, electronmicroscopic and autoradiographic study different types of nerve sheath tumors were classified. Their cellular population was quantitatively evaluated in the electron microscope. In the neurinoma the predominant cell was found to be the Schwann cell, but in the different types of neurofibromata a variable content of connective tissue cells was noted. T-HE DIFFUSE NEUROFIBROMATA SHOWED A QUANTITATIVE CELLULAR COMPOSITION SIMILAR TO NORMAL PERIPHERAL NERVES. In the plexiform neurofibroma a large number of fibroblasts were present and in the argyrophilic neurofibroma high content of perineurial cells was found. In autoradiographic sections the tumors showed in general a low proliferation rate (L.i. 1-3.6%). In the argyrophilic neurofibrom a higher labelling index (9.5%) was found.

Adolescent↗
PubMed1977

[Teratologic-neurotoxicologic studies on biglumide (K-2004) and thalidomide].

Comparison of the teratogenic and neurotoxic influence of thalidomide with the new hypnosedative preparation Biglumide (K-2004) revealed significant differences. Malformations could be seen only after treatment with thalidomide. Some results concerning the thalidomide-treated group of animals could be interpreted as a retardation of development in the posterior root ganglia.

Animals↗