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Biomedical subjects

A Vaheri

Publications and source records attributed to A Vaheri.

At least 361 records · Page 20Linked to original sources
PubMed1982

Fibronectin in exudative pleural effusions.

Fibronectin is a glycoprotein found in body fluids, loose connective tissue matrix and in basement membranes. Fibronectin in pleural effusion was found to be immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis. Fibronectin isolated from pleural fluid by affinity chromatography on gelatin-Sepharose had a polypeptide pattern similar to that of plasma fibronectin in SDS-polyacrylamide gel electrophoresis. In 28 patients with infectious or non-specific pleural effusion fibronectin concentrations in pleural fluid were 335 +/- 104 micrograms/ml (mean +/- SD), in 15 patients with malignant disease the concentrations were 369 +/- 173 micrograms/ml and in 26 patients with tuberculosis 441 +/- 103 micrograms/ml. The highest concentrations, 605 +/- 252 micrograms/ml, of fibronectin in pleural fluid were detected in 14 patients with connective tissue diseases. The results suggest that increased fibronectin concentrations reflect the presence of a pleurisy due to connective tissue disease or tuberculosis rather than other infectious or malignant disease.

Bacterial Infections↗
PubMed1982

Diagnostic value of cerebrospinal fluid antibodies in herpes simplex virus encephalitis.

Antibodies to different viruses and bacteria were measured in the cerebrospinal fluid (CSF) of six patients with herpes simplex virus encephalitis proven by brain biopsy and in five others with a presumptive diagnosis. Antibodies to herpes simplex virus but not to other organisms appeared in the CSF of all patients after the first weeks of the illness. Herpes simplex virus antibodies were not found in control CSF. The antibodies persisted in the CSF and the serum/CSF antibody ratio remained altered, 32:1 to less than 1:1, in all cases during the follow-up to 29 months or until death. The CSF albumin level was normal and the IgG index (formula: see text) elevated in four proven and three presumptive cases indicating a local antibody production; in four patients the findings were inconsistent. These results suggest that prolonged antigen stimulation is present in the central nervous system after acute herpes simplex encephalitis and that serological measurements combined with immunoglobulin and albumin determinations may provide a tentative but not definite diagnosis in some cases after the acute phase of encephalitis together with a method for follow-up of patients.

Adult↗
PubMed1982

Acute encephalitis of viral origin.

75 patients with acute encephalitis of confirmed or suggestive viral or virus-like etiology showed a predominance of herpes simplex virus (HSV) as an etiological agent (13.3-32.0%) in all age groups without seasonal variation and increasing in number during years. Mumps, occurring mainly in female patients, was next in order and thereafter coxsackievirus B, varicella-zoster, and adenoviruses, followed by multiple coincident infections, and a large number of occasional agents. HSV seems to have displaced tick-borne encephalitis virus as the major cause of acute encephalitis in Finland. Pregnancy appeared to increase susceptibility to HSV encephalitis. The outcome was associated with the etiological agent in the first hand, HSV and nonviral microbes appeared unfavourable, but also with the clinical symptomatology, particularly altered consciousness, mental symptoms and focal neurological signs. The need for exact and rapid diagnosis in all cases of acute encephalitis is underlined in view of the possibility of specific therapy.

Acute Disease↗
PubMed1982

Endo- and ectocervical human uterine epithelial cells distinguished by fibronectin production and keratinization in culture.

Human ecto- and endocervical uterine epithelia grow in culture as stratifying and nonstratifying cell layers, patterns reflecting the differentiation of the corresponding cells in vivo. We found that both cultures synthesized and secreted fibronectin but very little other known glycoproteins of basal laminae, laminin, and type IV collagen. Fibronectin production was observed only in the lining marginal cells of the expanding periphery of ectocervical islands, but differentiating and keratinizing cells had loss fibronectin. Most cells in endocervical epithelial cultures grew as a monolayer and produced fibronectin. After stratification of the ectocervical cells, the cytokeratin polypeptide pattern switched to the large-molecular-weight type. In endocervical cultures, the low-molecular-weight keratin polypeptides persisted. Fibronectin production thus appears to be linked to the state of differentiation of the epithelial cells, and fibronectin may function in the attachment of the basal cells to underlying basal lamina matrix.

Cell Differentiation↗
PubMed1981

Posttranslational modifications in the biosynthesis of type IV collagen by a human tumor cell line.

Factors responsible for the high extent of intracellular posttranslational modifications in type IV collagens were studied in a cultured human tumor cell line, HT-1080. These cells do not synthesize any detectable amounts of interstitial collagens but produce type IV collagen at a high rate, corresponding to about one-third of the production of interstitial collagens by cultured human skin fibroblasts. Prolyl 4-hydroxylase activity was lower in the HT-1080 cells than in human skin fibroblasts, there being a rough correlation between this enzyme activity and the rate of 4-hydroxyproline formation in these two cell types. The differing extents of the respective modifications could largely be explained by differences in the activities of lysyl hydroxylase and the hydroxylysyl glycosyltransferases between the two cell types. No difference ws found in prolyl 3-hydroxylase activity, however, even though the extent of 3-hydroxylation of proline residues was about 6-fold in the type IV collagens. In experiments where the HT-1080 cells were studied in suspension, a lag of about 100 min was found before the secretion of type IV collagen from the cells became linear. Pulse-chase experiments in suspension indicated that all the intracellular enzyme reactions proceeded for about 40 min, presumably due to the slow triple-helix formation in type IV collagens. This slow helix formation apparently contributed to the high extent of all the intracellular modifications but was not a major factor.

Cell Line↗
PubMed1981

Retrovirus p30-related antigen in human syncytiotrophoblasts and IgG antibodies in cord-blood sera.

Sensitive immunological techniques were used to detect retrovirus markers in human pregnancy. A total of 1,540 human cord-blood sera were tested for retrovirus-reactive IgG antibodies using solid-phase enzyme immunoassay and purified RD 114 virus as antigen. Of these, 118 (7.7%) sera were positive. Blocking assays with specific animal anti-p30 sera, use of control antigen, and electrophoretic protein experiments combined with immunological detection indicated that the human antibodies reacted specifically with the p30 protein. The occurrence of antibodies in cord-blood serum had a highly significant correlation to complications during pregnancy and also correlated to the number of previous abortions and stillbirths. When goat anti-RD 114 p30 serum was used in the peroxidase-anti-peroxidase tissue staining procedure, p30-related antigen was detected in sections of all placental specimens (early and term pregnancies, blighted ova, hydatidiform moles, destructive moles and choriocarcinomas). However, in each case only syncytiotrophoblastic cells were positive. These findings, supplemented with different types of blocking tests, lead us to conclude that retrovirus p30-related antigen is selectively expressed in the highly differentiated syncytiotrophoblasts, which in the normal placenta are directly exposed to maternal blood. It is suggested that retrovirus-reactive antibodies may represent an autoimmune-like immune response to the p30-related syncytiotrophoblast antigen escaping during cellular damage.

Antibodies, Viral↗
PubMed1981

Temperature-dependent and transformation-associated changes in polyamine metabolism in normal and Rous sarcoma virus-infected chick embryo fibroblasts.

Tertiary cultures of chick embryo fibroblasts infected and transformed by the wild-type Rous sarcoma virus, when actively growing at 35 degrees C, had higher putrescine levels than the respective uninfected cells. Transformed cells also had much higher specific activity of ornithine decarboxylase (EC 4.1.1.17) than the normal fibroblasts. At 41 degrees C the difference in putrescine levels between the normal and the transformed cells was less marked, and both cell types showed a relative accumulation of spermine. Cultures infected with the NY68 mutant virus, which is temperature-sensitive for transformation, showed at 41 degrees C normal cell morphology and intermediate polyamine patterns, while at 35 degrees C a transformed phenotype was found in both aspects. In shift-down experiments a change towards the permissive temperature pattern of polyamine metabolism was evident within 2-3 h. Difluoromethylornithine, a specific and irreversible inhibitor of ornithine decarboxylase efficiently reduced the enzyme activity as well as the levels of both putrescine and spermidine in all culture types and temperatures. Incubation of Rous sarcoma virus-transformed cells with 3 mM difluoromethylornithine for 36 h did not affect the maintenance of the transformed state. Likewise, when NY68-infected cultures were exposed to difluoromethylornithine at 41 degrees C for 12 h and then shifted down to 35 degrees C, the appearance of the transformed morphology took place concomitantly with that of the control cultures without respective changes in the polyamine levels. This suggests that the transformation-associated pattern of polyamines in chick embryo fibroblasts is not a prerequisite for morphological transformation of these cells.

Animals↗
PubMed1981

Extracellular matrix proteins characterize human tumor cell lines.

Extracellular matrix proteins synthesized and secreted by adherent human tumor cell lines were analyzed using metabolic labelling with glycine and proline in the presence of ascorbate, polypeptide analysis and polyacrylamide gel electrophoresis, affinity chromatography, collagenase digestion, and immunofluorescence staining. The results showed a characteristic pattern of matrix proteins for each tumor cell type. Tumor cell lines of mesenchymal origin produced mostly interstitial types (I and II) of collagen and fibronectin. Carcinoma cell lines secreted only basement membrane proteins, type IV collagen, laminin and fibronectin, but not interstitial collagen. A melanoma and a rhabdomyosarcoma cell line produced type V of procollagen that has not previously been described in cell culture. Neuroblastoma cells were shown to be phenotypically heterogeneous also with respect to matrix protein production. We propose that the analysis of extracellular matrix proteins may serve as an adjunct in the classification of human tumors.

Cell Line↗
PubMed1981

Regulation of collagen post-translational modification in transformed human and chick-embryo cells.

Changes in the regulation of collagen post-translational modification in transformed cells were studied in three established human sarcoma cell lines and in chick-embryo fibroblasts freshly transformed by Rous sarcoma virus. The collagens synthesized by all but one of these and by all the control human and chick-embryo cell lines were almost exclusively of types I and/or III. The relative rate of collagen synthesis and the amounts of prolyl hydroxylase activity and immunoreactive protein were markedly low in all the transformed human cell lines. The other enzymes studied, lysyl hydroxylase, hydroxylysyl galactosyltransferase and galactosylhydroxylysyl glucosyltransferase, never showed as large a decrease in activity as did prolyl hydroxylase, suggesting a more efficient regulation of the last enzyme than of the three others. The chick-embryo fibroblasts freshly transformed by Rous sarcoma virus differed from the human sarcoma cells in that prolyl hydroxylase activity was distinctly increased, whereas the decreases in immunoreactive prolyl hydroxylase protein and the three other enzyme activities were very similar to those in the simian-virus-40-transformed human fibroblasts. It seems possible that this increased prolyl hydroxylase activity is only a temporary phenomenon occurring shortly after the transformation, and may be followed by a decrease in activity later. The newly synthesized collagens of all the transformed cells that produced almost exclusively collagen types I and/or III had high extents of lysyl hydroxylation, and there was also an increase in the ratio of glycosylated to non-glycosylated hydroxylysine. The data suggest that one critical factor affecting modification is the rate of collagen synthesis, which affects the ratio of enzyme to substrate in the cell.

Animals↗
PubMed1981

Thrombin affects fibronectin and procollagen in the pericellular matrix of cultured human fibroblasts.

We have studied the effects of human thrombin on the isolated pericellular matrix of cultured human lung fibroblasts. Cell-free matrices were prepared from confluent cultures of cells by extraction with sodium deoxycholate and hypotonic buffer after radiolabeling the cultures with [14C]glycine. After the extraction, only a few radiolabeled polypeptides were retained on the culture dishes. These were identified as fibronectin, procollagens, and as yet unidentified polypeptides with molecular weights of 180 000, 140 000, 66 000 and 43 000. The matrices were exposed to thrombin in serum-free medium and the changes in the matrix-associated proteins were studied in autoradiograms of polyacrylamide gels. As a result of the treatment, there was massive release of both fibronectin and procollagen from the matrices into the medium. In addition , thrombin cleaved the 66 000 dalton polypeptide to a 62 000 dalton form that remained in the matrix. Collagenase treatment did not bring about the release of fibronectin or affect the 66 000 dalton protein. Some procollagen was also cleaved by thrombin; when high concentrations of thrombin were used cleavage of fibronectin took place. These effects of thrombin may operate in wounded areas in vivo.

Cell-Free System↗
PubMed1981

Fibronectin in human solid tumors.

Fibronectin in human solid tumors was studied by indirect immunofluorescence staining of biopsy material. Altogether 73 tumors were examined, comprising 12 sarcomas, 3 melanomas 1 reticulum cell sarcoma, 39 carcinomas, 6 benign soft-tissue tumors and 12 benign epithelial tumors. In all sarcomas the individual tumor cells were surrounded by a network of fibronectin which was continuous with the stroma. The distribution of fibronectin was similar in the benign soft-tissue tumors. In contrast, no fibronectin was detected in the individual carcinoma cells or in their periphery. However, the reactive connective tissue stroma of carcinomas was strongly connective tissue stroma of carcinomas was strongly positive for fibronectin. This was true also for the stroma of benign epithelial tumors. These results show that, contrary to the situation in cell culture, in vivo sarcoma cells and benign soft-tissue tumor cells contain fibronectin in their pericellular matrix. On the other hand, fibronectin can be used to distinguish carcinomas from sarcomas in vivo.

Carcinoma↗
PubMed1981

C-reactive protein in acute viral infections.

A sensitive solid-phase enzyme immunoassay procedure was used to determine the concentrations of C-reactive protein (CPR) in the acute and convalescent phase sera of patients with verified rubella, herpes simplex, cytomegalo, influenza A or B, enterovirus, or mycoplasma infection. In all infection groups about 90% (80% for influenza) elevated CRP values were observed in the acute phase sera (mean values in the different groups 16-57 micrograms/ml), the highest values exceeding or approaching 100 micrograms/ml. The serum CRP values were highest in all groups before the specific serum antibodies were detectable and decreased approaching the upper limit or normal controls (2 microgram/ml) within 2 weeks. Notable individual variation in the CRP production was seen. We conclude tha serum CRP determination should not be used as a reliable criterion to distinguish bacterial and viral infections.

C-Reactive Protein↗