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Biomedical subjects

A Vaheri

Publications and source records attributed to A Vaheri.

At least 343 records · Page 19Linked to original sources
PubMed1982

Chronic encephalomyelitis with specific increase in intrathecal mumps antibodies.

Symptoms of severe encephalomyelitis developed in a 31-year-old man in 1967. He had a high serum antibody titre to mumps virus associated with a polymorphic cell reaction and an increased protein concentration in cerebrospinal fluid (CSF). He recovered considerably within a year and was able to resume work. In 1975 his condition deteriorated again; it improved during the following few years, but a further deterioration then occurred. In March, 1981, the complement-fixing antibody titre to mumps virus was 1/32 in the serum and 1/4 in the CSF. In November, 1981, the CSF IgG index was increased and the altered serum/CSF antibody ratio persisted. The specificity of the altered antibody ratio was confirmed by the single radial haemolysis test and an immunoassay specific for mumps virus. Antibodies against the mumps virus envelope glycoprotein, M-protein, and nucleoprotein could be demonstrated by immunoprecipitation and the antibody patterns in serum and CSF were similar. Antibodies against other microorganisms were not detected in the patient's CSF, and mumps antibodies were not found in the CSF specimens of 57 control patients. This case may be an example of a new disease-chronic mumps virus infection in the central nervous system.

Adult↗
PubMed1982

Regulation of proline 3-hydroxylation and prolyl 3-hydroxylase and 4-hydroxylase activities in transformed cells.

Prolyl 3-hydroxylase activity and the extent of collagen proline 3-hydroxylation were studied in six transformed and three control human cell lines. In the transformed cell lines, the enzyme activity was markedly high in two, similar to that in control cells in two and significantly low in two. The extent of proline 3-hydroxylation was markedly high in cell lines with high enzyme activity, but it was also significantly high in some transformed cell lines with enzyme activities similar to those in the controls. The results thus suggest that, in addition to the amount of enzyme activity present, the rate of collagen synthesis also affects the extent of proline 3-hydroxylation in the newly synthesized collagen. The effect of acute cell transformation on prolyl 3-hydroxylase and 4-hydroxylase activities was studied by infecting chick-embryo fibroblasts with Rous sarcoma virus mutant NY68, temperature-sensitive for transformation. At the permissive temperature prolyl 3-hydroxylase activity showed a more rapid increase and decrease than did prolyl 4-hydroxylase activity, the maximal activity for both enzymes being about 2.5 times that in the control chick fibroblasts. When the transformed cells were shifted to the non-permissive temperature the decays in the elevated enzyme activities were similar, suggesting identical half-lives.

Animals↗
PubMed1982

Biosynthesis of type V procollagen by A204, a human rhabdomyosarcoma cell line.

The A204 cell line, derived from a human rhabdomyosarcoma, was studied in culture for its capacity to synthesize collagen types and other extracellular matrix proteins. The cells synthesized and secreted into the culture medium collagenous proteins with apparent molecular weights of 220,000 and 150,000. These were identified as the pro alpha 1 and pro alpha 2 chains of type V collagen by immunoprecipitation and by peptide mapping. The pro alpha 1(V) chain was made in excess of a 2:1 ratio for pro alpha 1(V) to pro alpha 2(V), and a fraction of the pro alpha 1(V) chains together with all of the pro alpha 2(V) chains participated in intermolecular disulfide bonding. The chains were extensively glycosylated at hydroxylysyl residues in ascorbate-supplemented cultures. A fraction of the secreted pro alpha 1(V) chains was processed to the p alpha 1(V) form, but further processing in the culture medium was very slow and the type V collagen molecules deposits in the extracellular matrix apparently retained large non-triple helical domains. Since the A204 cell line does not produce other collagen types, it may prove useful in further studies of the biosynthesis of type V procollagen.

Cell Line↗
PubMed1982

Novel vesicular extrusions during cell spreading.

During the late stages of cell spreading in vitro, the cells extrude a vesicular material into the medium. This phenomenon was observed in human glia and glioma cells as well as in human diploid fibroblasts MRC-5 and WI-38 cells. This extrusion of vesicular material is inhibited by cytochalasin-B and colcemid suggesting the involvement of microfilaments and microtubules and the active nature of this event. It appears that the cells may be excreting damaged surface components by a mechanism similar to patching, capping and endocytosis.

Cell Line↗
PubMed1982

The cellular target for the plasminogen activator, urokinase, in human fibroblasts - 66 000 dalton protein.

The effects of urokinase, the plasminogen activator of human urine, on the isolated substratum-attached pericellular matrices of cultured human lung fibroblasts were studied in serum-free conditions. Pericellular matrices were prepared from dense cultures of human lung fibroblasts after labelling of the cultures with radioactive glycine. Extraction of the cultures with sodium deoxycholate and hypotonic buffer gave a reproducible pattern of polypeptides when analyzed in polyacrylamide gels. The isolated pericellular matrix was subsequently exposed to affinity chromatography-purified urokinase. Urokinase affected a 66000-dalton protein but none of the other matrix polypeptides. The appearance of a 62000-dalton protein that remained attached to the matrix was seen concomitantly suggesting that it was derived from the 66000-dalton protein. The 66000-dalton protein is the first known cellular target for urokinase.

Cells, Cultured↗
PubMed1982

Deposition of an intermediate form of procollagen type III (pN-collagen) into fibrils in the matrix of amniotic epithelial cells.

We have followed the deposition and maturation of the pericellular matrix of amniotic epithelial cell cultures for up to eight weeks using metabolic labeling and immunoelectron microscopy. This matrix contains mainly collagen type III and fibronectin. Cleavage of the carboxypropeptide occurred after secretion of the procollagen molecules into the medium but was not accompanied by a significant release of the aminopropeptide. The early matrix, as isolated from the cultures by a deoxycholate procedure, contained collagenous proteins predominantly composed of pN alpha 1(III) chains, which still possessed the aminopropeptide, and only little material in the form of alpha 1(III) chains. The relative amount of alpha 1(III) chains increased during subsequent days of culture. Electron microscopy showed two types of structures in the matrix: thin fibrils, ranging from 10 to 30 nm in diameter, with no apparent cross-striation, and 50-500 nm thick bundles composed of filamentous and amorphous material. In the fibrils, immunoferritin electron microscopy showed a regular staining for the aminopropeptide of procollagen type III with a periodicity of 71 nm. These collagenous fibrils did not stain for fibronectin which was found in the bundles. Since most of the aminopropeptide in the matrix appeared covalently linked as pN-collagen, we conclude that the deposition of this intermediate form of procollagen is a general mechanism in collagen type III fibrillogenesis.

Amnion↗
PubMed1982

Deposition of basement membrane proteins in attachment and neurite formation of cultured murine C-1300 neuroblastoma cells.

The deposition of the basement membrane glycoproteins, laminin, fibronectin, and type IV procollagen was studied by indirect immunofluorescence microscopy during the attachment and differentiation of murine C-1300 neuroblastoma cells. A typical cytoplasmic perinuclear staining for the basement membrane antigens was seen both in undifferentiated and differentiated cells. Freshly seeded suspended cells lacked surface fluorescence but in two hours after plating, distinct punctate laminin deposits became discernible on the ventral surface of the cells. Notably, in sparsely seeded undifferentiated cultures, the cell-associated extracellular laminin deposits could only be detected under the primary attaching cells, whereas daughter cells in clonal cell colonies lacked such fluorescence. In cultures induced to neurite formation with dibutyryl cyclic AMP, laminin deposition was also detected in association with the growing cytoplasmic extensions. No distinct differences were found between the secreted proteins of cultures of differentiated and nondifferentiated neuroblastoma cells, but the patterns of fucosylation of high-molecular weight proteins in the two cultures were markedly different. We conclude that cultured neuroblastoma cells both synthesize, secrete and deposit laminin. The distribution of laminin during neuroblastoma cell attachment and neurite extension suggests that this glycoprotein may be involved in cell-to-substratum interactions in C-1300 cell cultures.

Animals↗
PubMed1982

Transformation of MMC-E epithelial cells by acute 3611-MSV: inhibition of collagen synthesis and induction of novel polypeptides.

Mouse embryo epithelial cells MMC-E were transformed by novel fibrosarcoma-inducing murine sarcoma virus 3611-MSV. The cells were analyzed for the production and deposition of pericellular glycoproteins by immunofluorescence and by radioactive metabolic and cell surface labeling techniques followed by analysis in polyacrylamide gels and fluorography. The pericellular fibronectin matrix was lost, but unlike in virus-transformed fibroblastic cells, the production of fibronectin was not affected. The major differences detected were decrease in collagen production and initiation of synthesis of two major glycoproteins with Mr 58,000 and 60,000. Cell surface carbohydrate labeling indicated that after 3611-MSV transformation the cells expressed Mr 100,000 and 68,000 polypeptides. The present and previous results show that viral transformation of epithelial cells induces different transformed phenotypes that are associated with distinct alterations in pericellular glycoproteins.

Animals↗
PubMed1982

Structure of the pericellular matrix: association of heparan and chondroitin sulfates with fibronectin-procollagen fibers.

Immunofluorescent staining of a pericellular matrix produced by cultured human embryonic skin fibroblasts showed a codistribution among fibronectin, heparan sulfate proteoglycans and part of the chondroitin sulfate in a fibrillar network. Isolated matrix in an "intact" form could be scraped off the dish after detergent solubilization of the cells. On centrifugation in cesium chloride density gradients, most sulfated glycosaminoglycans and matrix proteins remained associated and were recovered at a density of 1.34 g/cm3 (greater or equal to 2 M CsCl). However, when 4 M guanidine hydrochloride was included in the gradient medium, the components dissociated, suggesting that the sulfated glycosaminoglycans are bound to matrix proteins by strong noncovalent linkages. Interactions between sulfated glycosaminoglycans produced by the fibroblasts and fibronectin could also be demonstrated by affinity chromatography on immobilized plasma fibronectin and by immunoprecipitation of fibronectin in conditioned culture medium, which resulted in a coprecipitation of the sulfated glycosaminoglycans. In these two systems, the fibronectin glycosaminoglycan bonds were broken at 0.2 M salt and were apparently weaker than the bonds responsible for the structural integrity of the matrix. These findings implicate heparan and chondroitin sulfate proteoglycans as integral compounds of the pericellular matrix fibers and suggest that the association of the proteoglycans with the fibronectin-procollagen matrix is stabilized by multiple molecular interactions.

Cells, Cultured↗
PubMed1982

Cerebrospinal fluid IgG bands and virus-specific IgG, IgM, and IgA antibodies in herpes simplex virus encephalitis.

To characterize the immune response of the central nervous system in herpes simplex virus (HSV) encephalitis, cerebrospinal fluid (CSF) specimens of 7 biopsy proven and 7 presumptive herpes simplex virus (HSV) encephalitis patients were studied, using sodium dodecyl sulfate polyacrylamide gel electrophoresis for the presence of CSF IgG bands, and solid-phase enzyme immunoassays for HSV-specific antibodies. IgG bands were detected in all CSF specimens of the patients, as early as day 6 and up to day 1088. A novel, unidentified, 120 000 dalton polypeptide was found in the CSF of most of the patients, in a total of 25/50 specimens, but not in the controls. This polypeptide was evident by day 6, its intensity fluctuated and it was present in specimens collected as late as day 855. HSV-specific antibodies, of either IgG, IgM, or IgA class, were not detected in the CSF during the first week of illness. IgG antibodies appeared later in all patients and persisted to the end of the follow-up of 3 years. The fact that CSF IgG bands were present in some patients before the appearance of HSV antibodies, and also persisted longer, suggests that the IgG response is not restricted to HSV-specific antigenic determinants.

Adult↗
PubMed1982

Extracellular matrix proteins of human epidermal keratinocytes and feeder 3T3 cells.

Cultures of human epidermal keratinocytes obtained from adult epidermis were initiated using irradiated BALB/3T3 cells as feeder layers. At different stages of confluence of the epidermal islands, feeder cells were removed and the extracellular matrix proteins of both pure component cells and cocultures were analyzed biochemically and by immunochemical methods and compared to those of skin fibroblasts of the same donors. The keratinocytes synthesized and secreted fibronectin and small amounts of laminin and type IV collagen. In addition, a nondisulfide-linked collagenous polypeptide (Mr = 120,000) was synthesized by the keratinocytes and was confined to the cell layers. Collagenous polypeptides with Mr = 120,000 were also synthesized by organ cultures of epidermal tissue and were detected in its acid or detergent extracts but again no secretion to culture medium was found. The Mr = 120,000 collagen had biochemical and immunological properties distinct from those of types I-V collagens. In immunofluorescence of keratinocyte cultures, fibronectin staining was prominent in the lining marginal cells of the expanding periphery of the epidermal cell islands but was not detected in the terminally differentiating cells in the upper layers of stratified colonies. Very little type IV collagen was found deposited in pericellular matrix form by the keratinocytes. In contrast, the mouse 3T3 feeder cells were found to produce both type IV collagen and laminin in addition to the previously identified connective tissue glycoproteins of fibroblasts, interstitial procollagens, and fibronectin. Basement membrane collagen of the 3T3 cells was found deposited as apparently unprocessed procollagen alpha 1(IV) and alpha 2(IV) chains. The production in culture conditions of basal lamina glycoproteins by the fibroblastic feeder cells may promote the attachment and growth of the cocultured keratinocytes.

Basement Membrane↗
PubMed1982

Trial with human leucocyte interferon and vidarabine in herpes simplex virus encephalitis: diagnostic and therapeutic problems.

A combination therapy of human interferon, vidarabine, and dexamethasone was administered to six patients with proven (Patients I-III) or presumed (Patients IV-VI) herpes simplex virus encephalitis (HSVE). Interferon combined with dexamethasone was given to one patient with presumed HSVE (Patient VII). Leucopenia and elevated serum transaminase levels appeared in all patients and a diffuse bleeding in one of them. Patients II, III and IV died, 26, 43, and 209 days after the onset of encephalitis, respectively. Patients I, V, VI, and VII were left with moderate brain damage although their physical condition was good. HSV encephalitis presents diagnostic difficulties, complementary diagnostic methods are needed, and current therapeutic trials must be considered as preliminary.

Adult↗