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Biomedical subjects

S Morikawa

Publications and source records attributed to S Morikawa.

At least 235 records · Page 13Linked to original sources
PubMed1987

Platelet aggregability and platelet volume in the postoperative course: problems in the platelet aggregation test derived from the measurement of platelet volume.

Platelet count, aggregability and volume in the postoperative course of 20 patients were examined. Platelet count was decreased on the 1st postoperative d, and increased on the 7th and 14th d compared with the preoperative value. The maximal aggregation rate of platelets induced by ADP was decreased on the 3rd postoperative d, and then recovered to the preoperative level. In contrast, platelet volume was only slightly increased on the 3rd postoperative d. In this study, there was no correlation between platelet aggregability and platelet volume in PRP. We have proposed one parameter, 'platelet concentration ratio' (platelet concentration in PRP/platelet concentration in whole blood). In the postoperative course, this concentration ratio changed depending on platelet volume, and possibly on other conditions of blood such as hematocrit, viscosity and specific gravity. The concentration ratio influenced the subpopulations of platelets in PRP. Platelet aggregation tests may be performed using PRP in which platelet subpopulations differ from those in whole blood, especially in the postoperative state.

Adult↗
PubMed1987

Effect of 1 alpha,25-dihydroxyvitamin D3 on proliferation of activated T-cells and established human lymphotropic virus type I-positive T-cell lines.

The effects of 1 alpha, 25-dihydroxyvitamin D3 [1,25-(OH)2D3] on proliferation and de novo DNA synthesis were studied in the following established human leukemia cell lines: lymphoblastic T-cell lines HPB-ALL, CCRF-HSB-2, p12/lchikawa, and HPB-MLT; adult T-cell leukemia- (ATL) and human lymphotropic virus type I (HTLV-I)-infected T-cell lines HUT102, HUT-102B2, MT-1, MT-2, MJ, C2/MJ, KH-2, KH-2Lo, HPB-CTL-1, and ATN-C1; ATL-derived B-cell lines ATL-BK9 and ATL-BK10; lymphoblastic B-cell line Daudi; and myelocytic-monocytic lineage cell lines HL-60 and U937. 1,25(OH)2D3 inhibited proliferation and de novo DNA synthesis of phytohemagglutinin-P-activated T-cells and certain established HTLV-I-positive T-cells. However, it did not inhibit immature lymphoblastic T- and B-cells or ATL-derived B-cells. The degree of inhibition depended on the dose of 1,25(OH)2D3 and the heterogeneity of the established HTLV-I-positive T-cells. KH-2 and subclone KH-2Lo were markedly inhibited, and HPB-CTL-1 was moderately inhibited. Marked inhibition of DNA synthesis in KH-2Lo cells was observed in the proliferative phase of the cell cycle. No inhibition of KH-2Lo proliferation or expression of interleukin-2 and transferrin receptor was noted after removal of 1,25(OH)2D3 from the culture medium. 1,25(OH)2D3 inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced multinucleated cell formation of various HTLV-I-positive T-cell lines and TPA-induced HTLV-I p19 expression in KH-2Lo cells.

Antigens, Viral↗
PubMed1986

Stimulatory effect of calmodulin antagonists on phospholipid base-exchange reactions in rabbit platelet membranes.

The properties of Ca2+-dependent incorporation of [3H]serine, [3H]ethanolamine and [3H]choline into the corresponding phospholipids mediated by base-exchange enzymes in rabbit platelet membranes were studied in the presence or absence of the calmodulin antagonists chlorpromazine, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), all of which markedly activate three base-exchange reactions. The base-exchange activities were dependent on Ca2+ both in the presence and absence of the drugs. Other metal ions tested did not stimulate the base-exchange reactions, even in the presence of the drugs. Apparent Km values for serine, ethanolamine and choline were not affected significantly by the concentration of Ca2+, with or without the drugs. [3H]Serine incorporation into phospholipid was competitively inhibited by ethanolamine and choline, [3H]choline incorporation was competitively inhibited by serine and ethanolamine, whereas [3H]ethanolamine incorporation was competitively inhibited by serine and noncompetitively by choline. These competitive and noncompetitive relations between each base were also not affected by the drugs. The amount of 45Ca2+ binding to platelet membranes was decreased by the drugs dose dependently. A weaker calmodulin antagonist, N-(6-aminohexyl)-1-naphthalenesulfonamide (W-5), only slightly stimulated the base-exchange reactions, but did clearly inhibit 45Ca2+ binding to the membranes, in the same manner as that of the other calmodulin antagonists used. The concentration of chlorpromazine, trifluoperazine, W-7 and W-5, required to produce half-maximal inhibition of Ca2+ binding, was approximately 30 microM. These results suggest that the calmodulin antagonists used activate the base-exchange reactions only in the presence of Ca2+ without changing the affinity of each free base to base-exchange enzymes. The activation of the base-exchange reactions was not due to the increase in free Ca2+ caused by the drug-induced inhibition of Ca2+ binding to platelet membranes.

Animals↗
PubMed1986

IL-2- and IL-2-R- independent proliferation of T-cell lines from adult T-cell leukemia/lymphoma patients.

Human T-cell leukemia/lymphoma virus I (HTLV-I) is known to be associated with adult T-cell leukemia/lymphoma (ATL) as an etiological agent. The mechanism of leukemogenesis by HTLV, however, is still obscure. Two hypotheses have been proposed concerning abnormalities in IL-2 production and its receptor (Tac antigen) expression based on the experimental observations of IL-2-dependent ATL cell lines. In this study, we examine these hypotheses by using 3 leukemic T-cell lines from 3 Japanese patients with ATL. These cell lines were cultivated and established without addition of IL-2 to the culture medium. Cell-surface phenotype analysis by immunofluorescence with monoclonal antibodies (MAbs) and IL-2 binding assays revealed that one of the ATL cell lines, HPB-ATL-2, expresses only a minimal amount of IL-2 receptor (IL-2-R) on the cell surface and binds less radiolabelled human recombinant IL-2 than the other highly Tac-positive cell lines. Expression of Tac antigen in all ATL cell lines was not affected by IL-2, anti-Tac MAb or the tumor-promoter phorbol ester in the culture medium. The culture supernatant from these cell lines showed no IL-2 activity toward Con-A-stimulated human peripheral blood lymphocytes, and their growth was not affected by additional IL-2 in cultures. IL-2-independent growth and constitutive expression of its receptors on the cell surface were evident in our ATL cell lines. However, dense expression of IL-2 receptors was not essential for stimulation of leukemic proliferation of T cells by HTLV-I. Trans-activation of the PX40 gene product of HTLV-I for activation of IL-2-R gene might not be coincidentally associated with stimulation for cell proliferation.

Adult↗
PubMed1986

Effects of Ca2+ on ethanolaminephosphotransferase and cholinephosphotransferase in rabbit platelets.

The effects of Ca2+ on ethanolaminephosphotransferase [EC 2.7.8.1] and cholinephosphotransferase [EC 2.7.8.2] activities in rabbit platelet membranes were studied using endogenous diglyceride and CDP-[3H]ethanolamine or CDP-[14C]choline as substrates. Both transferases required Mn2+, Co2+, or Mg2+ as a metal cofactor and the optimal concentrations of the metals for both activities were about 5, 10, and 5 mM, respectively. When 5 mM Mg2+ was used as a cofactor, both transferase activities were inhibited by a low concentration of Ca2+ (half maximal inhibition at approx. 15 microM). In the presence of 5 mM Mn2+, however, approx. 5 mM Ca2+ was required to produce half maximal inhibition. The Ca2+-induced inhibition was reversible and the rate of the inhibition was not affected either by the concentrations of the CDP-compound or by exogenously added diacylglycerol. The relationship between Ca2+ and both Mg2+ and Mn2+ on the transferase activities was competitive. 45Ca2+ binding (and/or uptake) to the platelet membranes was inhibited by Mn2+, Mg2+, and Co2+, in a concentration-dependent manner. However, the inhibitory effects of the three metal ions on the total Ca2+ binding (and/or uptake) did not correlate with the activation of both transferase activities by the three metal ions in the presence of Ca2+. These results suggest that both transferase activities are regulated by low concentrations of Ca2+ in the presence of optimal concentrations of Mg2+, and that the inhibition is mediated directly by Ca2+, which interacts with a specific metal cofactor binding site(s) of the transferases.

Animals↗
PubMed1986

Effects of calmodulin antagonists on serine phospholipid base-exchange reaction in rabbit platelets.

Effects of the calmodulin antagonists chlorpromazine, trifluoperazine, and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide on phospholipid metabolism were examined in rabbit platelets using [3H]serine, [3H]ethanolamine, [3H]choline, and [3H]glycerol. All these drugs markedly stimulated the incorporation of [3H]serine into phosphatidylserine. On the other hand, these drugs had only a slight effect on the rate of incorporation of [3H]ethanolamine and [3H]choline into the corresponding phospholipid. When [3H]glycerol was used as a precursor of the phospholipids, 3H-labeled phospholipids were mainly composed of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. Although the phosphorus content of phosphatidylserine was about 40% of that of phosphatidylcholine in rabbit platelets, the amount of phosphatidylserine labeled with [3H]glycerol was less than 2% of that of the labeled phosphatidylcholine, and calmodulin antagonists slightly stimulated the incorporation of [3H]glycerol into phosphatidylserine. Treatment with calmodulin antagonists caused a marked decrease in the content of endogenous free serine with concomitant increase in the contents of endogenous free ethanolamine and choline. On the other hand, the contents of other free amino acids, including essential and non-essential amino acids, were unchanged. These results suggest that the calmodulin antagonists we used did not affect de novo synthesis of phosphatidylserine, but did stimulate the serine phospholipid base-exchange reaction in rabbit platelets.

Amino Acids↗
PubMed1986

Left renal vein hypertension in patients with left renal bleeding of unknown origin.

The pullback pressure from the left renal vein (LRV) to the inferior vena cava was studied in 16 patients with left renal bleeding of unknown origin (group A), 15 patients with hematuria of miscellaneous laterality (group B), and nine control subjects (group C). The mean pressure gradients were 5.0 +/- 2.0 mm Hg (mean +/- SD) in group A, 1.9 +/- 1.0 mm Hg in group B, and 1.1 +/- 0.9 mm Hg in group C. The mean pressure gradient of group A was significantly higher than that of groups B and C (P less than .001). From the results of control studies, we regarded pressure gradients greater than or equal to 3.0 mm Hg as indicative of LRV hypertension. With this criterion, 88% (14 of 16) of the patients in group A had LRV hypertension, which was considered a cause of hematuria. Analysis of the results of renal angiography in the 31 patients revealed that opacification of collateral pathways of the LRV was a significant angiographic finding in LRV hypertension.

Adolescent↗
PubMed1986

Natural killer cell activity against a variety of target cell lines in normal persons: NK-target sensitivity and effect of age and sex on NK levels.

Natural killer (NK) cells have been implicated as first line of defence mechanism for carcinogenesis in humans. A lot of studies of depressed NK activity in patients with malignancies have supported this. Two major problems, however, in these studies are the choice of normal controls and target cells. To study this problem, peripheral mononuclear cells (PBMC) of sixty-six normal subjects from young and elderly, males and females were tested for NK function against twenty target cell lines with a microcytotoxicity assay. The result was shown that no sex or age difference existed with respect to NK function, except for a slight but significant decreased in NK activity of young female to K562 target cells. Target cells were divided into four groups by their NK sensitivity, namely, high, moderate, low and refractory sensitive. In general, NK activity of healthy persons is considered to remain stable and polyspecific in our results.

Adolescent↗
PubMed1986

[Effects of neonatal androgenization on endometrial carcinogenesis and natural killer (NK) activity].

The effects of neonatal androgenization on endometrial carcinogenesis and natural killer (NK) cell activity which may facilitate the development of malignant tumors were studied. Abnormal uterine proliferation was not detected in any of 162 NR during a 800-day observation period. In contrast, 3 atypical hyperplasias, 3 adenocarcinomas and one squamous cell carcinoma of the uterus were detected in 61 ASR after 500 days of age. In ASR, obesity became prominent with aging and spleen weight also increased after 500 days of age. Concerning the target cell of NK cell activity assay, YAC-1 lymphoma cells are the best cell line of the three cell lines in a variety of experimental conditions. NK cell activity of both NR and ASR decreased with age. NK cell activities of ASR significantly decreased at both 250 and 500 days of age in comparison with those of NR. Such persistently reduced NK cell activity which implies that a decline in immune surveillance is one of the important factors in endometrial carcinogenesis of ASR after 500 days of age.

Adenocarcinoma↗
PubMed1985

Effects of calmodulin antagonists and calmodulin on phospholipid base-exchange activities in rabbit platelets.

Effects of various calmodulin antagonists and calmodulin on the incorporation of serine, ethanolamine and choline into the corresponding phospholipids, such as phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine by Ca2+-stimulated base-exchange reactions in rabbit platelet membranes were studied. Under a Ca2+-EGTA buffer system, the incorporation of three bases were stimulated by Ca2+ in a biphasic manner. Minimum requirement of free Ca2+ for the reactions was found to be around 0.5 microM and maximal incorporation took place at high Ca2+ concentrations (3-5 mM). Various calmodulin antagonists such as chlorpromazine, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, not only activated the three reactions but also greatly enhanced their sensitivity to Ca2+ (K0.5, 0.1-0.3 microM). In the absence of Ca2+, however, the drugs did not show any effect on the reactions. The concentrations of the drugs required for half maximal stimulation were approx. 30-40 microM. Although platelet membranes contained endogenous calmodulin (0.3-0.6 microgram/mg of membrane protein), the addition of exogenous calmodulin inhibited choline exchange activity but had no or little effect on serine or ethanolamine exchange activity. The results suggest that in the presence of low Ca2+ concentrations, these drugs markedly stimulate base-exchange activities, and choline exchange activity may be regulated by calmodulin.

Animals↗