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Biomedical subjects

J Peltonen

Publications and source records attributed to J Peltonen.

At least 145 records · Page 8Linked to original sources
PubMed1986

Collagens in neurofibromas and neurofibroma cell cultures.

Neurofibromas contain approximately 30-50% collagen of their lipid-free dry weight, which is about half of the value of skin but approximately twice that described for peripheral nerve endoneurium. Immunohistochemical stainings indicate that neurofibromas contain types I, III, IV, and V collagens and fibronectin. Most of the neurofibroma cells are type IV collagen and S-100 protein positive, which provides immunohistochemical evidence that neurofibromas are mostly composed of Schwann cell-like cells. The proteoglycan/collagen ratio is 4 to 10 times higher in the neurofibromas than in the surrounding dermal tissue. This would explain the typical soft consistency of the neurofibromas and may contribute to a favorable milieu for tumor growth. Pure fibroblastic cell cultures are obtained from neurofibromas after repeated passages. The cultured cells synthesized type I and III collagens and fibronectin, indicating that these cells are important in the production of the fibrous connective tissue proteins in neurofibromas.

Cells, Cultured↗
PubMed1985

Endoneurial fibrosis following nerve transection. An immunohistological study of collagen types and fibronectin in the rat.

Indirect immunofluorescent techniques with antibodies to type I, III, and V collagens and fibronectin were used to study rat sciatic nerve tributaries after transection with intact contralateral nerves as controls. Codistribution of type I and III collagens characterized the epineurium of normal nerve. In the perineurium, however, type I collagen was absent, but type III and V collagens and fibronectin were detected. Type I and III collagens were codistributed in the endoneurial stroma where a homogeneous staining by antibodies to fibronectin was also observed. During the 4-week observation period after transection the perineurium reacted by slight thickening which was most clearly demonstrated by staining with antibodies to fibronectin and to type V collagen. A widening of the type I-negative cleft also occurred. Endoneurial, type V collagen-positive cuffs around the nerve fibers became disorganized, and a concomitant increase of the stroma containing type I and III collagens and fibronectin was observed. The codistribution of the fibrous collagen types appeared similar in normal epineurium and endoneurium. Type V collagen was located in the perineurium and in endoneurial cuffs surrounding the nerve fibers. The present data indicate that collagen accumulation takes place in the perineurium and endoneurium of transected nerve. The cell type responsible for the synthesis of the connective tissue material is discussed.

Animals↗
PubMed1985

A double-blind crossover evaluation of naproxen and piroxicam in osteoarthritis of hip or knee.

Seventy-five patients participated in a randomized, double-blind, crossover study, the aim of which was to compare the efficacy and safety of naproxen 1000 mg once daily with piroxicam 20 mg once daily for the treatment of osteoarthritis of hip or knee. Treatment periods of 4 weeks each were preceded by placebo wash-out periods of up to 1 week. The patients were examined clinically at every stage of the trial. Each treatment group exhibited significant improvement in weight-bearing and night pain, over-all disease severity, and the separate evaluations of patient response by physician and patient. There were no significant differences between the drugs in type, severity, or number of side-effects. Neither of the drugs influenced the patients' laboratory data. Night pain was less for patients using naproxen than for those taking piroxicam, and patients indicated greater preference for naproxen than for piroxicam. Naproxen was statistically superior to piroxicam as measured by decreased weight-bearing pain and over-all disease severity, the separate physician and patient global assessments of patient response to therapy, and physician preference. In this study, naproxen 1000 mg once daily was more effective than piroxicam 20 mg once daily for the treatment of osteoarthritis.

Adult↗
PubMed1984

Neurofibromatosis tumor and skin cells in culture. II. Structural proteins with special reference to the cytoskeletal and cell surface components.

Structural proteins of cultured neurofibromatosis (NF) tumor and skin cells were studied with reference to control skin fibroblasts. In polyacrylamide gel electrophoresis (PAGE)/fluorography the banding patterns of the cell lysates were markedly similar. NF tumor cells, however, produced a 60 kD band with a stronger and a 48 kD band with a lighter protein staining and metabolic labeling intensity. Furthermore, skin cells were also characterized by a 26 kD protein and the tumor cells by a 22 kD protein with high metabolic labeling intensity. Neuraminidase/galactose oxidase/NaB3H4-labeled NF skin and control skin cells possessed a 220 kD protein that was less intensively labeled in the tumor cells. The banding pattern of the skin cells was also characterized by a protein with slightly lower molecular weight (86 kD) than that of the tumor cell lysates (90 kD). In all cell lines studied indirect immunofluorescence stainings revealed bright arrays of vimentin type intermediary filaments but no desmin, cytokeratin, glial fibrillary acidic protein (GFAP), or neurofilament proteins. NF skin and control skin cells possessed well developed actin-containing bundles of microfilaments, while those of the tumor cells lacked a typical stress-fiber organization. The general morphology of the tumor cell cultures was also irregular. Transmission electron microscopy revealed no basic differences in the structure of intermediary filaments or microfilaments. The present data provide basic knowledge of neurofibromatosis skin and tumor cells and demonstrate that cultured cells originating from neurofibromas are defective in both their intracellular and extracellular organization.

Actins↗
PubMed1984

Type IV and V collagens in von Recklinghausen's neurofibromas. An immunohistochemical and electrophoretical study.

Type IV and V collagens were localized in neurofibromas from six patients with von Recklinghausen's neurofibromatosis (NF) using the peroxidase anti-peroxidase (PAP) technique. The collagens were also isolated from neurofibromas by pepsin digestion and fractionating salt precipitations and demonstrated with sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Staining reactions for both collagens were detected in most of the cells in the disorganized NF tumor tissue. These cells also were S-100 protein-positive and were considered to be of Schwannian cell origin, while the type IV collagen-negative cells showed fibroblastoid, mast cell and histiocytic characteristics. Type IV collagen detection was also used to study the structure of a neurofibroma after 3 weeks in tissue culture. The proportion of fibroblastoid, type IV collagen-negative cells increased significantly in the cultured neurofibromas and "buds" containing solely fibroblastoid cells were seen at the periphery of the tumor fragments. Cultured 6th passage tumor cells produced type V but no type IV collagen as estimated with SDS-PAGE. Further, two malignant Schwannomas from a patient with NF were stained with antibodies to type IV collagen. A positive staining reaction was associated only with the vascular walls in the malignant Schwannomas suggesting that type IV collagen expression is linked with cell differentiation. The present data show that the detection of type IV collagen using the PAP-method is useful in studying the organization of tumors with mixed cell populations such as neurofibromas. Large neurofibromas might also serve as a source for the isolation of human type IV and V collagens.

Collagen↗
PubMed1984

Distribution of different collagen types and fibronectin in neurofibromatosis tumours.

Collagen types I, III, IV and V and fibronectin were localized in neurofibromas from six patients with von Recklinghausen's neurofibromatosis (NF) using indirect immunofluorescence (IIF) and peroxidase anti-peroxidase (PAP) techniques. Type I and III collagens were abundantly and rather evenly present in the tumours and formed a continuous network, but were absent from the capillary endothelial walls and were sparse in the perineurium of the occasional nerve fascicles. The type III/type I + type III collagen ratio in neurofibromas varied from 17.4% to 37.3% when estimated with cyanogen bromide peptide analysis. Fibronectin was detected in areas where type I and III collagens were present but was most intensively stained in the vascular walls and perineurium. Type IV collagen was detected at the dermo-epidermal junction of the skin overlying the tumours, in the endothelial cells of the capillaries, the perineurium and endoneurium. Furthermore, in the tumourous stroma there was plenty of type IV collagen appearing as a discontinuous patchy pattern suggesting abundant basement membrane material associated with cells forming the tumours. Type V collagen distribution was very similar to that of type IV collagen.

Collagen↗
PubMed1984

Distraction of the growth plate. Experiments in pigs and sheep.

Distraction of the growth plate of the distal radius was performed on 15 pigs and 10 sheep of growing age. The separation of the plate from the metaphysis occurred within 4-6 days after the operation. The distraction rate was 1-1.5 mm/day and was continued for 1-3 weeks. Consolidation of the separation area occurred within 6 weeks. Oxytetracycline bone labelling showed that the ossification developed toward the centre of the separation line from the metaphysis and from the inner layer of the periosteum as well as from the physeal side. The growth of the bone continued after the distraction procedure and in most cases the growth plate was open when examined radiologically after the distraction.

Animals↗
PubMed1984

Experimental epiphyseal separation by torsional force.

Separation of the proximal tibial epiphysis from the metaphysis by torsional force was experimentally studied using cadaver bone preparations from 19 adolescent sheep. The energy needed to displace the epiphysis increased in correlation with an increase in the age of the animal. The separated epiphyseal and metaphyseal surfaces were examined using scanning electron microscopy. In the younger animals the separation line passed through the area of hypertrophied chondrocytes. In the animals more near skeletal maturity the separation occurred in a more sinuous fashion and also through spongious bone.

Age Factors↗
PubMed1983

Neurofibromatosis tumor and skin cells in culture.

Skin fibroblasts and tumor cells were cultured from four patients with peripheral von Recklinghausen's neurofibromatosis (NF). The cell type enriched in culture from the tumors carried the fibroblastic Thy 1.1. cell surface antigen and produced fibronectin, like fibroblasts from skin of NF-patients or from control persons. In electron micrographs the NF tumor and NF skin cells were similar to the control skin fibroblasts; elongated in shape, contained tubular mitochondria, variable amounts of granular endoplasmic reticulum, numerous lysosomal inclusion bodies and collections of 5 nm filaments. Trypsinized cells were fractionated with centrifugation in a Percoll density gradient. All cell lines produced only one sharp band of viable cells at the buoyant density of 1.03. Compared with the NF skin or control skin fibroblasts the NF tumor cells, however, produced a less well organized peri- and extracellular matrix estimated from fibronectin fluorescence. The nuclear sizes were measured from photographs of the cultures. The nuclei of all four tumor cell lines were larger than those of the skin fibroblasts of the corresponding patients. Neurofibromatosis tumor cells thus resemble skin fibroblasts in their density and in some ultrastructural properties but are different in their growth pattern and synthetic functions.

Adult↗
PubMed1982

Treatment of pseudarthrosis of the clavicle.

Twelve patients were operated on between 1974 and 1979 for painful pseudarthrosis of the clavicle. The time from the injury to the operation ranged from 4 months to 12 years. We used an AO plate fixation and cancellous bone graft. The patients were able to return to work within 2 months on average. The AO plate was removed 8 to 12 months after the operation. At the 1 year follow-up all the pseudarthroses had consolidated and the patients were satisfied with the result of the treatment.

Adult↗
PubMed1981

Collagen synthesis in cells cultured from v. Recklinghausen's neurofibromatosis.

Subcutaneous tumors of a patient with v. Recklinghausen's neurofibromatosis contained about 31% collagen calculated on the basis of lipid-free dry weight. Slices of the tumors synthesized collagen at a rate (4.7-8.5% from total protein) which was higher than that of the skin slices (2.8-5.9%). Neurofibromatosis cells were cultured from tumors of two patients. They synthesized relatively much more collagen than cultures of skin fibroblasts of the same patient or of healthy age-matched control persons. The second patient's cultures were studied in detail. The cell densities of these cultures were higher and expressed more variation than the densities of control skin fibroblasts. Ion exchange cellulose chromatograms, SDS-polyacrylamide gel electrophoresis and 3-hydroxyproline analysis of the radioactive proteins made by the cultures indicate that most of the collagenous proteins resembled type I collagen. High proliferative capacity and high collagen synthesis of selected neurofibromatosis cells explains the growth of solid tumors.

Cells, Cultured↗
PubMed1980

A rapid assay to measure collagen synthesis in cell cultures.

Limited pepsin digestion and precipitation of resistant parts of proteins with perchloric acid on glass-fiber filters has been used as a rapid way to determine the radioactive collagen secreted into fibroblast culture media. The specificity of the pepsin cleavage was tested by digesting [14C]- or [3H]proline- and [3H]tyrosine-labeled procollagens. Radioactivities obtained with this method were comparable with those obtained with collagenase digestions or hydroxyproline determinations. Dialysis of the samples is avoided and the radioactive collagen can thus be determined from the small medium samples obtained from microtest plates. The method was used to localize a collagen synthesis-increasing factor in preparative isoelectric focusing of microphage culture media.

Animals↗
PubMed1979

Isoelectric focusing of macrophage culture media and the effect of the fractions on the synthesis of DNA and collagen by fibroblasts.

Macromolecules from rat peritoneal macrophage culture media were separated into 30 fractions by flat bed isoelectric focusing (IEF). The fractions were tested for their influence on thymidine and proline incorporation into cultured rat granuloma fibroblasts. Three fractions, stable after freezing and lyophilization, were of interest: one inhibiting thymidine incorporation (focusing at pH 7.3-7.6), another stimulating thymidine incorporation (focusing at pH 4.4-5.3), and the third stimulating proline incorporation into cells and medium collagen (focusing at pH 10.2-10.7). The last also exhibited a ribonuclease (RNase) activity with a pH-optimum of 7.0-7.5.

Animals↗