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T Koike

Publications and source records attributed to T Koike.

At least 649 records · Page 36Linked to original sources
PubMed1988

Terminal differentiation and calcification in rabbit chondrocyte cultures grown in centrifuge tubes: regulation by transforming growth factor beta and serum factors.

Rabbit chondrocyte cultures on plastic dishes are capable of depositing a cartilaginous matrix, although the matrix does not calcify unless high levels of phosphate are added to the medium. In the present study, we cultivated a pelleted mass of rabbit growth-plate chondrocytes in the presence of Eagle's minimum essential medium supplemented with 10% fetal bovine serum and 50 micrograms of ascorbic acid per ml in a plastic centrifuge tube. These cells proliferated for several generations and then reorganized into a cartilage-like tissue that calcified without additional phosphate. The deposition of minerals was observed only after synthesis of a short-chain collagen and alkaline phosphatase. Serum factors were required for the increases in alkaline phosphatase and calcium contents. 5-Bromo-2'-deoxyuridine abolished the increases in uronic acid, alkaline phosphatase, and calcium contents. Transforming growth factor beta, at very low concentrations, suppressed the expression of the mineralization-related phenotype by chondrocytes. These results suggest that cartilage-matrix calcification can be controlled by growth factor(s) and that chondrocytes induce the mineralization of extracellular matrix when terminal differentiation is permitted in the absence of an artificial substrate.

Alkaline Phosphatase↗
PubMed1988

Purification and characterization of a 400-kDa nonhistone chromatin protein that serves as an effective phosphate acceptor for casein kinase II from Ehrlich ascites tumor cells.

A nonhistone chromatin protein (NHCP) has been purified to homogeneity from a 0.5 M NaCl extract of Ehrlich ascites tumor cell (EAT cell) nuclei as a phosphate acceptor for casein kinase II using ion-exchange column chromatographies and Sephacryl S300 gel filtration. The purified NHCP (approximate Mr = 400,000) was found to be a tetramer of an Mr = 98,000 polypeptide (pI = 6.9) and to have high contents of glycine (15%) and serine (11.6%). This protein (designated as 400-kDa NHCP) was highly phosphorylated by casein kinase II (Mr = 130,000), but not by histone kinase. Casein kinase II phosphorylated only seryl residues of the purified 400-kDa NHCP. The NHCP bound with DNA, but not with RNAs, and the DNA binding ability of the protein was reduced when it was phosphorylated by casein kinase II. Moreover, we found that (a) the 400-kDa NHCP is present in large quantities in malignant mouse cells, such as EAT, EL-4, and Meth-A cells, but only slightly in normal tissues and cells; (b) the protein level is rapidly increased when mouse lymphocytes are treated with recombinant interleukin 2 (T cell growth factor) or concanavalin A; and (c) the kinase responsible for the 400-kDa NHCP phosphorylation in the chromatin of various mouse cells is a casein kinase II. These experimental results suggest that the 400-kDa NHCP acts as an effective phosphate acceptor for casein kinase II at the chromatin level and that an increased phosphorylation of the protein by the kinase may be implicated in the progress of cell differentiation and proliferation.

Amino Acids↗
PubMed1988

Effects of limited exposure of rabbit chondrocyte cultures to parathyroid hormone and dibutyryl adenosine 3',5'-monophosphate on cartilage-characteristic proteoglycan synthesis.

Treatment of rabbit chondrocyte cultures with PTH or (Bu)2cAMP for 30 h increased by 2- to 3-fold the incorporation of [35S]sulfate and 3H radioactivity with glucosamine as the precursor into large chondroitin sulfate proteoglycans characteristically found in cartilage matrix. However, PTH and (Bu)2cAMP did not increase either [35S]sulfate incorporation into small proteoglycans or the incorporation of 3H radioactivity into hyaluronic acid and other glycosaminoglycans. PTH and (Bu)2cAMP also increased the incorporation of [3H] serine into both proteoglycans and total protein. In all cultures described above, the stimulation of [3H]serine incorporation into proteoglycans exceeded that of [3H]serine incorporation into total protein. These data indicate that PTH and (Bu)2cAMP selectively stimulate cartilage proteoglycan synthesis while they increase total protein synthesis. Since cAMP seems to play a mediatory role in the action of PTH, we elected to examine the effects of a limited exposure of chondrocytes to PTH or (Bu)2cAMP on the synthesis of proteoglycans. Treatment with PTH or (Bu)2cAMP for only the initial 2-7 h did not increase the rates of incorporation of [35S]sulfate, the 3H radioactivity with glucosamine, and [3H]serine into proteoglycans, as measured at 30 h, despite the fact that this treatment brought about a rapid and transient rise in the cAMP level. Furthermore, the application of prostaglandin I2 at concentrations that increased cAMP levels in a similar fashion as did PTH did not affect [35S] sulfate incorporation into proteoglycans. These observations suggest that in addition to the transient rise of cAMP, other biochemical changes are required for elaboration of the effect of PTH on proteoglycan synthesis. Although cAMP analogs mimic some of the effects of PTH in chondrocytes, the nucleotides and PTH appear to stimulate proteoglycan synthesis by different mechanisms.

Animals↗
PubMed1988

Rabbit articular chondrocytes in soft agar are useful to test the effect of non-steroidal anti-inflammatory drugs on chondrocyte replication.

The effect of non-steroidal anti-inflammatory drugs (NSAIDs) on rabbit articular chondrocyte proliferation was examined in soft agar and in conventional cultures on plastic dishes. Indomethacin, acetylsalicylate, and naproxen (10(-4) M) decreased the efficiency of colony formation by chondrocytes in soft agar in the presence of fibroblast growth factor, although the drugs had little effect on the proliferation of chondrocytes on plastic dishes. On the other hand, tiaprofenic acid (10(-4) M) did not have any adverse effect on chondrocyte replication in either culture the two systems. Rabbit articular chondrocyte growth in soft agar will be a useful test system for examining the effects of anti-arthritic drugs on cartilage metabolism and repair.

Agar↗
PubMed1988

[Brain ischemia and endothelial cell damage--immunohistochemical study using factor VIII related antigen as a marker].

As brain capillaries do various works necessary for maintaining the homeostasis of neurons, their disruptions may play an important role in the establishment of ischemic brain damage. It is also said that brain capillaries response to ischemia more functionally than structurally and their microstructural features remain unchanged for a long time of ischemia. Therefore, a new method is expected to be introduced that can evaluate the ischemic changes of endothelial cells on a histological level more sensitively than conventional histological methods. In the present study we investigated immunohistochemical reactivity of factor VIII related antigen (F VIII RAg), a specific and representative marker of vascular endothelial cells, in normal and ischemic brains. In the experiment, cerebral ischemia was induced by occlusion of the unilateral common carotid artery in adult mongolian gerbils. The periods of occlusion were 1, 2, 3, 6, 12, and 24 hours, in five animals respectively. After occlusion each brain was obtained by decapitation and quickly frozen at -80 degrees C and 5-6 micron sections were cut in a cryostat at -20 degrees C and dried at 37 degrees C. The staining for F VIII RAg was done by the peroxidase-antiperoxidase method using specific antiserum to human F VIII RAg. In normal gerbil's brains, the positive staining for F VIII RAg was observed in endothelial cells of arteries, veins and capillaries. In major vessels the staining was intense, but neurons and glia were not stained.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Histochemical study on enzymatic barrier of the newly formed vessels in infarcts].

To investigate the properties of the vessels newly formed in cerebral infarcts, we performed enzyme histochemical study for alkaline phosphatase and gamma-glutamyl transpeptidase that are membrane enzyme of capillary endothelial cells in the brain as well as immunohistochemical study for factor VIII related antigen and laminin. Adult mongolian gerbils were used in the experiment to produce cerebral infarcts. The animals showing clear neurological signs of ischemia after occlusion of the left common carotid artery were selected. Following one hour ischemia blood flow was reperfused and the animals were allowed to grow and sacrificed at predetermined intervals ranging from two days to two years. The stainings for alkaline phosphatase and gamma-glutamyl transpeptidase were performed by Brustone method and Rutenburg method respectively, and those for factor VIII related antigen and laminin by PAP method, in frozen sections. Four days after ischemia, vessels of a slightly large size that were running irregularly with reactivity of factor VIII related antigen and circumscribed by laminin were observed in the marginal zone of the infarcts. These newly formed vessels increased in number during the second and the third week also in the center of the infarcts, and one month after ischemia began to decrease. However, a number of vessels were seen in the infarcts, whose features were comparatively similar to those of normal vessels. These vessels remained as long as for two years. The number of the vessels with alkaline phosphatase and gamma-glutamyl transpeptidase activity did not increase during the first week. They increased later during the second and third week.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1988

[A case of a perforated duodenal ulcer coincident with a gastric carcinoma].

A 44-year-old male patient under treatment for a duodenal ulcer for the past 9 years visited our clinic because of a sudden pain in the epigastric region. He was diagnosed as having a perforated duodenal ulcer, so an emergency laparotomy was performed. In this operation, the coexistence of a gastric carcinoma was clarified, and a subtotal gastrectomy with an R2 dissection was done at the same time. The coexistent gastric carcinoma was localized to a size of 20 x 12 mm within the gastric proper mucosa. The infiltrated range of the cancer was as wide as 120 x 80 mm, extending to the proper tunica muscularis. This case was seen as manifesting a relative early stage of scirrhous carcinoma.

Adenocarcinoma, Scirrhous↗
PubMed1988

Immunohistochemical identification of infiltrating mononuclear cells in tubulointerstitial nephritis associated with Sjögren's syndrome.

Using monoclonal antibodies, immunoperoxidase analysis was performed on eight renal biopsy samples obtained from patients with Sjögren's syndrome-associated tubulointerstitial nephritis. In all cases the interstitial infiltrates were predominantly CD5-positive T-cells (mean 66%), whereas both B-cell (CD19-positive) and monocyte (CD15-positive) populations participated to a lesser degree. CD16-positive NK/K cells were rarely encountered. The CD4/CD8 ratio was consistently higher than 1.0 (mean 2.08). The lymphocytes which invaded the tubular epithelial cells to present a feature of tubulitis were CD8-positive, suggesting that they were cytotoxic T-cells. These results were in general accord with those obtained in the salivary glands of patients with Sjögren's syndrome. It was thus concluded that the same immunological process was probably operative in the renal tubulointerstitial tissue as in the salivary glands to induce the characteristic tissue changes of Sjögren's syndrome.

Adolescent↗
PubMed1988

Monoclonal hybridoma anti-cardiolipin antibodies from SLE mice.

To determine whether the anti-cardiolipin antibodies are identical with the lupus anticoagulant and other antibodies to phospholipids and DNA, we prepared monoclonal hybridoma autoantibodies to cardiolipin from SLE-prone MRL/lpr mice and characterized their specificity. Using a somatic cell hybridization technique, we established three hybridoma clones which produce antibodies to cardiolipin (CAL-1: IgG2b, k, CAL-2: IgM, k and CAL-3: IgM, k). These hybridoma antibodies preferentially reacted with cardiolipin and phosphatidylserine, weakly reacted with phosphatidylinositol, but not with other phospholipids such as phosphatidylcholine, sphingomyelin, phosphatidylethanolamine and VDRL antigen. Two hybridoma anti-cardiolipin antibodies bound to ssDNA and were found to act as the lupus anticoagulant when mixing activated partial thromboplastin time with cephalin. These autoantibodies may prove to be good tools for elucidating mechanisms of thrombosis, thrombocytopenia, fetal loss and other related manifestations found in patients with systemic lupus erythematosus.

Animals↗