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Biomedical subjects

M A Spycher

Publications and source records attributed to M A Spycher.

At least 55 records · Page 3Linked to original sources
PubMed1983

The ultrastructural localization of fibronectin in the lining layer of rheumatoid arthritis synovium: the synthesis of fibronectin by type B lining cells.

The distribution of fibronectin in the lining layer of inflamed rheumatoid arthritis (RA) synovium has been ultrastructurally investigated using an anti-human plasma fibronectin antibody. The hyperplasia of lining cells was prominent in the lining layer of the inflamed RA synovium. A high level of fibronectin was localized in this region. Ultrastructurally the fibronectin was observed on the surface of both type A (type M) and type B (type F) cells, and in the extracellular fibrin-like material. This glycoprotein was detectable in rough endoplasmic reticulum (RER), some Golgi apparatus, and peripheral vesicles of type B cells. On the other hand, RER and Golgi apparatus of type A cells failed to be immunostained with the antibody. Type A cells occasionally contacted each other with interdigitation of cytoplasmic processes, and a high amount of fibronectin was localized in this region. These findings indicate that fibronectin is synthesized along the classic secretory pathway through RER and Golgi apparatus of type B cells. On the contrary, type A cells seem not to be associated with the local synthesis of the glycoprotein. Fibronectin may play a structural role in organizing these proliferated lining cells by promoting cell adhesion. The synthesis of fibronectin by proliferated type B cells may be responsible in part for the local increase of this glycoprotein in the lining layer of RA synovium.

Adult↗
PubMed1983

The localization of fibronectin in rheumatoid arthritis synovium by light and electron microscopic immunohistochemistry.

The distribution of fibronectin in rheumatoid arthritis (RA) synovium has been investigated by light and electron microscopic immunohistochemistry using an antihuman fibronectin antibody. Heavy accumulation of fibronectin was observed in the lining layer and the areas of proliferation of fibroblasts. Rough endoplasmic reticulum (RER) and peripheral vesicles of proliferated type B lining cells and fibroblasts contained large amounts of fibronectin. Thus these cells seem to participate actively in the local synthesis and secretion of this glycoprotein. Type A lining cells and migrated mononuclear phagocytes contained many phagolysosomes in some of which dense accumulation of fibronectin was observed. Some of the materials in the phagolysosomes, with dense accumulation of fibronectin, resembled the fibrinous material-fibronectin complexes frequently seen in the pericellular spaces. Accordingly fibronectin seems to play a role in the clearance of fibrinous materials by these phagocytes. The proliferated capillaries and small vessels possessed multilamellated basement membranes with heavy accumulation of fibronectin. However, RER or Golgi apparatus of the endothelial cells contained no detectable amounts of fibronectin. This indicates that these cells do not actively participate in the synthesis of fibronectin and that the majority of this glycoprotein in the basement membranes originates in fibronectin from blood vessel exudate. Fibrinous material-fibronectin complexes were frequently seen on the endothelial cell surfaces. Circulating platelets and mononuclear cells occasionally came in contact with these complexes, suggesting an association of fibronectin with the formation and clearance of thrombi in the vascular lumina at the inflammatory sites of RA synovium.

Arthritis, Rheumatoid↗
PubMed1982

Subcellular distribution of aspartate aminotransferase isoenzymes in chicken heart: quantitative study.

1. The content of the two aspartate aminotransferase isoenzymes in isolated mitochondria and in the cytosolic fraction from chicken heart was determined by radioimmunoassays. 2. The cationic isoenzyme was found to be associated with the mitochondrial fraction; its content measured in the cytosolic fraction was within the range of that of contaminating mitochondrial marker enzymes. 3. The anionic isoenzyme was found exclusively in the cytosolic fraction, in mitochondria a content of less than 0.05% of the total was measured. 4. Thus, in birds, the anionic and the cationic isoenzyme of aspartate aminotransferase show the same strict intracellular heterotopism as found previously in mammals.

Animals↗
PubMed1981

Isolation and characterization of rough endoplasmic reticulum associated with mitochondria from normal rat liver.

A subfraction of rough endoplasmic reticulum (RER) characterized by its close association with mitochondria (MITO) was isolated from low speed pellets of normal rat liver homogenate under defined ionic conditions. This fraction enriched in MITO-RER complexes contained 20% of cellular RNA, 20% of glucose-6-phosphatase and 47% of cytochrome c oxidase activities. Morphologically, the isolated MITO-RER complexes closely resembled physiological associations between the two organelles commonly seen in intact liver. Partial dissociation of RER from mitochondria of the MITO-RER fraction was achieved by either EDTA (0.5 mM) or by hypotonic/hypertonic treatment of MITO-RER complexes. With the latter procedure approx. 70% of RER (RERmito) with 50% of ribosomes still attached could be separated from the inner compartments of mitochondria. This RERmoto exhibited a higher glucose-6-phosphatase activity than RER isolated as rough microsomes from the postmitochondrial supernatant. Isopycnic centrifugation on linear metrizamide gradients revealed that the mitochondria-associated part of RER corresponds to the high density, ribosome-rich subfraction of rough microsomes isolated in cation-free sucrose solution. The combined data demonstrate that a morphologically and biochemically distinct portion of RER is associated with mitochondria and support the concept of considerable intracellular heterogeneities in distribution of enzymes and enzyme systems along the lateral plane of the endoplasmic reticulum membrane system.

Animals↗
PubMed1980

Achondrogenesis type I: light and electron-microscopic studies.

The light- and electron-microscopic structure of articular and costal cartilage in a case of achondrogenesis type I has been described. The most characteristic ultrastructural change in the chondrocytes was conspicuous dilatation of the rough endoplasmatic reticulum (RER) which contained amorphous electronopaque material. This change in the RER was accompanied by marked hypertrophy of the Golgi apparatus; the matrix was basically unchanged.

Achondroplasia↗
PubMed1980

Electron microscopy: a method for the diagnosis of inherited metabolic storage diseases. Electron microscopy in diagnosis.

In the diagnosis of inherited metabolic diseases, electron microscopy has become an important method complementary to clinical, histological and biochemical assays. The characteristic ultrastructure of stored material as well as the site of accumulation in the cell are shown in a number of metabolic disorders. The most prominent advantages of electron microscopical techniques as compared to alternative techniques are discussed. One of the advantages is the fact that ultrastructural investigation requires only tissue samples of very small size, and another that its results may be obtained within two days. Moreover, transmission electron microscopy permits new and promising analytical methods such as quantitative estimation of organellar changes (morphometry) and energy dispersive X-ray elemental analysis (EDX).

Fabry Disease↗
PubMed1980

Glycogenosis type I (glucose 6-phosphatase deficiency): I. Ultrastructural morphometric analysis of juvenile liver cells.

The essential biochemical characteristic of von Gierke's disease is an inborn glucose-6-phosphatase deficiency and glycogen storage in the liver and kidney. This expresses itself morphometrically as an increased volume of glycogen per unit volume of the hepatocellular cytoplasm. Since glucose-6-phosphatase activity in patients studied is practically at the zero level, and the endoplasmic reticulum loses a large part of its membrane values, we conclude that the remaining endoplasmic reticulum represents glucose-6-phosphatase free membranes. A typical structural feature of the endoplasmic reticulum in von Gieke's disease is the appearance of "double contoured vesicles" (= pockets). These vesicles comprise approximately 3,5% of the total membrane system. The mitochondria play an important role in glycolysis and glycogen synthesis. It is thus to be expected that these organelles change in terms of their morphometric parameters in the course of glycogenosis type I. An important point in this direction is numerical mitochondrion reduction in combination with an unchanged mitochondrial volume.

Child, Preschool↗
PubMed1980

Prenatal mucopolysaccharidosis II (Hunter): a pathogenetic study.

A prenatal diagnosis of Mucopolysaccharidosis II (M. Hunter) was made early in a pregnancy at risk in a family with one affected child. An affected fetus was diagnosed on the basis of an abnormal incorporation and degradation of 35SO4 in 35SO4-labeled mucopolysaccharides in cultured amniotic cells. Dermatan sulfate and heparin sulfate concentrations in the supernatant of the amniotic fluid were high. In the aborted fetus, the diagnosis could be confirmed by 35SO4 incorporation studies in the cultured fibroblasts and in cultured brain cells as well as by the deficiency of the specific enzyme activity (iduronide sulfate sulfatase) in the organs of the fetus. beta-Galactosidase was in the low normal range in liver and spleen but significantly reduced in brain. Under electron microscopy, the mesenchymal cells of liver and spleen showed lysosomal storage of material, presumably mucopolysaccharides, in excess of normal. In the neurons of the spinal ganglia and spinal cord, "Zebra bodies" in statu nascendi were observed.

Female↗
PubMed1980

Quantification and particle size distribution of inhaled fibres in the lung.

The number and size distribution of fibres in the lungs of 11 asbestos-exposed and 10 nonexposed individuals were determined. For fibre isolation, low-temperature incineration of lung tissue was used. The mean numbers of fibres per gram of dry lung, based on light microscopy, were 141.9 X 10(6) and 1.5 X 10(6) in the asbestos-exposed and nonexposed lungs, respectively. The fibre length found most frequently ranged between 3-5 micrometers in both groups. Asbestos, either chrysotile or amphibole, was found only in the group occupationally exposed to asbestos. No correlation between number of fibres and lung pathology could be established.

Adult↗
PubMed1979

[Conspicuous accumulation of membranous glomerulonephritis following gold therapy in chronic polyarthritis--a side effect of a new preparation?].

The development of severe proteinuria or nephrotic syndrome as an adverse reaction to gold therapy in rheumatoid arthritis is well known. Morphologic examination reveals membranous glomerulonephritis in almost all cases. Since the beginning of 1978 there has been a striking increase in the number of such cases seen at this institute. 5 patients aged from 17 to 65 years who had been treated with sodium aurothiomalate for rheumatoid arthritis developed severe proteinuria. In all cases only minimal glomerular changes were observable by light microscopy. Electron microscopy demonstrated multiple electrondense, subepithelial deposits which were confirmed by fluorescence microscopy. In all cases characteristic lysosomes ("aurosomes") were demonstrated in the cytoplasm, mainly of the epithelial glomerular cells. This unusual accumulation of almost identical cases coincides with the introduction of a new gold preparation, Na-aurothiomalate (Tauredon), containing 46% metallic gold.

Adolescent↗
PubMed1979

Human articular cartilage in relation to age, A morphometric study.

The cell density of the weight-bearing area of normal femoral head cartilage was investigated in 65 cases of both sexes ranging from 6 to 90 years of age. In the maturing cartilage (until about the third decade), the cell density decreases, while in aging cartilage (30-90 years) it remains constant. Our results are in agreement with the main trend of earlier and similar investigations. The reason for contradictory reports is suggested to be due to differences in the selection of criteria for defining 'normal' cartilage. This problem is particularly acute with advancing age, where a great part of the available material shows degenerative changes.

Adolescent↗