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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 379 records · Page 21Linked to original sources
PubMed1994

Growth ability of human immunodeficiency virus type 1 auxiliary gene mutants in primary blood macrophage cultures.

A strain of human immunodeficiency virus type 1 that is strictly tropic for primary human blood cell cultures was constructed in vitro. Mutational studies on the vif, vpr, vpu and nef genes of this virus were performed to evaluate their biological functions in natural target cells. For this purpose, replication properties of mutant viruses in peripheral blood mononuclear cells (PBMCs) and macrophages (PBMPs) were determined. Three phenotypes with respect to virus replication were noticed: normal or mildly retarded growth (nef and vpr mutants), impaired growth (vpu mutant), and no growth (vif mutant). These results suggest that the Vif and Vpu proteins are more important than the Nef and Vpr proteins for virus replication in PBMCs and PBMPs.

Cell Line↗
PubMed1994

Human immunodeficiency virus Vpx is required for the early phase of replication in peripheral blood mononuclear cells.

Functional importance of Vpx protein of human immunodeficiency virus type 2 was evaluated in various types of cells. In 8 lymphocytic or monocytic cell lines tested, vpx mutant virus grew as well as wild-type virus. Only in primary peripheral blood mononuclear cell cultures, severely retarded growth of mutant virus was observed. No replication of vpx-minus virus was detected in primary macrophage cells. A highly sensitive single-round replication assay system was used to determine the defective replication phase in primary mononuclear cells of vpx mutant virus. In all cell lines examined, vpx mutant displayed no abnormality. In contrast, the vpx mutant was demonstrated to be defective at an early stage of the infection cycle in primary cell cultures. No evidence of a replication-defect at a late phase in primary cells of the vpx mutant was obtained by a transfection-coculture method. These results indicate that the virion-associated Vpx protein is essential for early viral replication process in natural target cells such as primary macrophages.

Cell Line↗
PubMed1994

Serum concentration of 7S collagen and prognosis in patients with the adult respiratory distress syndrome.

BACKGROUND--7S collagen, an N-terminal peptide of type IV collagen, is a primary constituent of the basement membrane. To evaluate whether the serum concentration of 7S collagen reflects the severity of inflammatory lung disease, the serum concentration of 7S collagen was measured in patients with adult respiratory distress syndrome (ARDS) and idiopathic pulmonary fibrosis (IPF). METHODS--A radioimmunoassay was used for the measurement of 7S collagen. Gas exchange abnormality was expressed as the arterial oxygen tension (PaO2) divided by the fractional concentration of inspired oxygen (FiO2). RESULTS--The mean (SD) concentration of 7S collagen was 2.7 (0.9) ng/ml in 10 healthy subjects, 5.0 (1.5) ng/ml in 11 patients with IPF, and 14.8 (9.7) ng/ml in 13 patients with ARDS. Significant differences were observed between the patients with ARDS and both healthy subjects and the patients with IPF. In the patients with ARDS serum concentrations of 7S collagen were strongly related to PaO2/FiO2 (r = -0.61). Moreover, the mean (SD) serum concentration of 7S collagen in the eight patients with ARDS who died (19.5 (10.2) ng/ml) was considerably higher than that of the five who survived (7.1 (2.1) ng/ml). CONCLUSION--These results suggest that serum levels of the 7S fragment of type IV collagen may have some prognostic value in ARDS.

Adolescent↗
PubMed1994

Overexpression of human lipoprotein lipase enhances uptake of lipoproteins containing apolipoprotein B-100 in transfected cells.

To investigate the role in lipoprotein metabolism of lipoprotein lipase (LPL) secreted by tissues, we established two cell lines. Fusion plasmids containing either human LPL cDNA or antisense LPL cDNA under control of the cytomegalovirus promoter were transfected into Chinese hamster ovary (CHO) cells, designated as CHO-LPL and CHO-anti-LPL, respectively. CHO-LPL constitutively produced a high level of LPL, whereas CHO-anti-LPL produced a minimal level. When very-low-density lipoprotein (VLDL) was incubated with CHO-LPL, VLDL triglycerides were hydrolyzed, intermediate-density lipoprotein (IDL) was produced, and apolipoprotein E contents increased. CHO-LPL took up and degraded 125I-VLDL at 37 degrees C four times more strongly than did CHO-anti-LPL. Whereas the degradation of apolipoprotein E-deficient VLDL was only 12% that of normal VLDL in CHO-LPL, structural changes of the lipoprotein, including apolipoprotein E expression on the lipoprotein surface, may be important for the cellular uptake of VLDL. Furthermore, we found that binding at 4 degrees C of VLDL and LDL to CHO-LPL was greater than to CHO-anti-LPL, and this binding difference was abolished by washing the cells with heparin. This suggests that cell surface LPL plays a role in the binding of lipoproteins to the cells. We conclude that both the composition of VLDL particles and their cellular binding are influenced by LPL secreted by cells, both of which may enhance the cellular uptake of VLDL.

Animals↗
PubMed1994

Elevated levels of interleukin-8 and leukotriene B4 in pulmonary edema fluid of a patient with reexpansion pulmonary edema.

We experienced a case of reexpansion pulmonary edema (RPE) after surgical treatment of pneumothorax. In this case, protein leakage and polymorphonuclear leukocyte (PMN) accumulation were observed in the reexpanded lung. Interleukin-8 and leukotriene B4 in edema fluid were increased at the onset of RPE. PMN elastase was also increased, though its peak was delayed. The plasma level of P-selectin, which mediates adhesion between PMN and endothelium, was elevated. We speculate that some of these fluid mediators may play important roles in chemotaxis and activation of PMN in the development of RPE.

Adult↗
PubMed1994

Secretion-recapture process of apolipoprotein E in hepatic uptake of chylomicron remnants in transgenic mice.

To investigate the role of apoE in hepatic uptake of chylomicron remnants, we studied chylomicron metabolism in transgenic mice overexpressing apoE in the liver. Plasma clearance of injected 125I-labeled human chylomicrons was fivefold faster in transgenic mice than in controls. Immunohistochemistry demonstrated that apoE was specifically localized at the basolateral surface of hepatocytes from fasted transgenic mice. After injection of a large amount of chylomicrons, the density of the cell surface apoE was markedly reduced and vesicular staining was observed in the cytoplasm, suggesting that the cell surface apoE was used for hepatic endocytosis of chylomicrons and remnants. Polyacrylamide gel analysis of chylomicrons and remnants that had been reisolated from plasma and from liver membrane after the injection of chylomicrons showed the particles to be enriched with apoE mainly after their influx into the liver rather than during their residence in plasma. These results provide strong evidence for the secretion-recapture process of apoE, whereby chylomicron remnants enter the sinusoidal space, acquire apoE molecules, and subsequently are endocytosed. Data from experiments with very low density lipoprotein and LDL showed that this system is specific for chylomicron remnants.

Animals↗
PubMed1994

Pathophysiological concentrations of glucose promote oxidative modification of low density lipoprotein by a superoxide-dependent pathway.

Oxidized lipoproteins may be important in the pathogenesis of atherosclerosis. Because diabetic subjects are particularly prone to vascular disease, and glucose autoxidation and protein glycation generate reactive oxygen species, we explored the role of glucose in lipoprotein oxidation. Glucose enhanced low density lipoprotein (LDL) oxidation at concentrations seen in the diabetic state. Conjugated dienes, thiobarbituric acid reactive substances, electrophoretic mobility, and degradation by macrophages were increased when LDL was modified in the presence of glucose. In contrast, free lysine groups and fibroblast degradation were reduced. Although loss of reactive lysine groups could be due to either oxidative modification or nonenzymatic glycation of apolipoprotein B-100, inhibition of lipid peroxidation by the metal chelator, diethylenetriamine pentaacetic acid, blocked the changes in free lysines. Thus, glycation of lysine residues is unlikely to account for the alterations in macrophage and fibroblast uptake of LDL modified in the presence of glucose. Glucose-mediated enhancement of LDL oxidation was partially blocked by superoxide dismutase and nearly completely inhibited by butylated hydroxytoluene. These findings indicate that glucose enhances LDL lipid peroxidation by an oxidative pathway involving superoxide and raise the possibility that the chronic hyperglycemia of diabetes accelerates lipoprotein oxidation, thereby promoting diabetic vascular disease.

Arteriosclerosis↗
PubMed1994

[Primary culture of bovine adrenocortical cells].

The isolated bovine adrenocortical cells are prepared aseptically by the use of collagenase and deoxyribonuclease. The isolated cells are suspended in Ham F-10 medium containing 5% fetal calf serum, 10% newborn calf serum, 2.5% horse serum and antibiotics. The seeded cells are cultured at 37 degrees C in a humidified atmosphere of 5% CO2 in air. Steroidogenic activity for ACTH reached the maximum in the 2- to 3-day primary cultured cells; the maximum response to ACTH in these cells is more intense than that in freshly isolated bovine adrenocortical cells. The primary cultured cells have prostaglandin, muscarinic, ATP and beta-adrenergic receptors that are linked to steroidogenesis in addition to ACTH and aldosterone receptors. Thus primary cultured bovine adrenocortical cells are a useful tool to study these receptors and the intracellular events that are associated with the receptors. We also demonstrated that the fura 2 loaded primary cultured monolayer cells on glass cover slips provide us much more information than suspended cells in the study of intracellular Ca2+ mobilization in adrenocortical cells.

Adrenal Cortex↗
PubMed1994

Plasma concentrations of substances suspected as uremic toxins in experimentally induced and spontaneous uremic dogs.

Plasma concentrations of four substances, a pyridine derivative (S7a), uric acid (UA), hippuric acid (HA) and kynurenic acid (KA), suspected as uremic toxins in dogs were determined in dogs with experimentally induced uremia by the ligations of renal arteries, spontaneous uremic dog patients and normal dogs. In experimentally induced uremic dogs, plasma concentrations of S7a, HA and KA showed continuous increase after the ligation of renal arteries together with a significant correlation to plasma creatinine concentration (Cre). Plasma UA concentration increased rapidly, but it showed a varying fluctuation without showing any correlation to Cre. Plasma concentrations of S7a, UA, HA and KA in spontaneous uremic dogs were almost within the ranges of those of experimentally induced uremic dogs.

Animals↗
PubMed1994

Autoimmune diseases as stem cell disorders.

Using an animal model for insulin-dependent diabetes mellitus (IDDM), the NOD mouse, we have demonstrated that allogeneic bone marrow transplantation (BMT) has a preventative effect on IDDM, and that a combined transplantation of pancreas and bone marrow can be used to treat IDDM. We have also shown that BMT has a curative effect on systemic autoimmune disease in (NZB x NZW) F1, BXSB, and (NZW x BXSB) F1 mice but not in MRL/lpr mice. Since MRL/lpr mice possess abnormal radioresistant hemopoietic stem cells (HSCs), they suffer a relapse 5 months after BMT. Recently, we have found that major histocompatibility complex (MHC)-matched stromal cells in the bone marrow are essential to the support of HSCs in the Go phase. We therefore attempted to treat autoimmune diseases in MRL/lpr mice by the transplantation of stromal cells with HSCs. Transplantation of HSCs with bone to recruit stromal cells was indeed found to have a curative effect on autoimmune diseases in the mice. These results indicate that BMT with bone graft will become a valuable strategy for the treatment of patients with both systemic and organ-specific autoimmune diseases. To prove that autoimmune diseases originate from defects in HSCs, we transferred the HSCs of autoimmune-prone mice to normal mice. BMT or transplantation of stem-cell concentrates induced organ-specific and/or systemic autoimmune diseases in [NOD-->C3H/HeN] and [(NZW x BXSB)F1-->C3H/HeN or C57BL/6J] chimeric mice. These results provide direct evidence that the etiopathogenesis of autoimmune diseases, including both organ-specific and systemic autoimmune diseases, is attributable to defects in the HSCs themselves. We further provide that various intractable diseases such as non-insulin-dependent diabetes mellitus and chronic nephritis (focal glomerulosclerosis) are also organ-specific autoimmune diseases, and that BMT can be used to treat them.

Animals↗
PubMed1994

[Changes in electrocardiographic findings with aging in a longitudinal study of 500 apparently healthy persons aged 60 years and older].

A number of studies have been published which have attempted to define the electrocardiographic (ECG) changes with aging, but most of them were obtained from cross-sectional studies. To distinguish ECG changes related to physiological aging from those associated with arteriosclerosis, we assessed the ECG changes of 500 apparently healthy subjects, aged 60 years and older in 1992, who had been followed at the Keio Health Consulting Center for over 15 years. All subjects had no overt cardiovascular diseases in 1992. We compared the ECG in 1992 with that taken over 15 years ago. Changes in ECG during that period were also reviewed. With aging, the mean axis deviated to the left, the mean QTc interval was shortened, and the mean PR interval was prolonged. ST segmental change, atrial overloading, bundle branch block developed newly in 16%, 8% and 7% of, respectively. There were no relationships among axis deviation, PR interval change, or QTc shortening and coronary risk factors. QTc prolongation and ST segmental change were strongly related to hypertension or impaired glucose tolerance. When ECG changes in those under 65 years old were compared with those over 80 years old, the incidence of ST segmental change in those over 80 years old was significant higher. This study was not a prospective study but suggested each type of ECG change related to aging was affected by physiological and/or pathological factors in a distinct way and had different phases of development and progression.

Aged↗
PubMed1994

Effects of Houttuyniae cordata and refinery final molasses on the development of offensive odor in porcine small intestine during storage.

Porcine small intestine evolved a specific offensive odor only 0.5 to 1 day after storage at 20 degrees C. We investigated the effects of Houttuyniae cordata (dokudami), refinery final molasses (RFM), green tea, and brown sugar on the evolution of methylmercaptan and ethanol, which were the main components of the volatiles which evolved from porcine small intestine in storage. Furthermore, we determined their antibacterial effect and deodorant activity against methylmercaptan, as possible factors in reducing the offensive odor. Addition of those materials reduced the offensive odor during storage. In particular, dokudami, green tea, and RFM markedly suppressed the evolution of methylmercaptan. RFM was most effective in suppressing the growth of bacteria. Dokudami had the highest deodorant activity, comparable to that of perilla leaves. However, the retardation of methylmercaptan evolution in situ cannot be simply explained by either of deodorant or antibacterial effect. It seems likely that the combined action of both effects affects the evolution of methylmercaptan in situ.

Animals↗
PubMed1994

Nafamostat mesilate reduces blood cell adhesion to cardiopulmonary bypass circuits: an in-vitro study.

Nafamostat mesilate (FUT-175) is a protease inhibitor, working as an inactivator of coagulation, fibrinolysis and platelet aggregation. Although FUT-175 directly blocks contact factors in coagulation, it also may decrease activation of humoral cascade systems when used in cardiopulmonary bypass circuits. We performed an in vitro study using fresh human blood in the following cardiopulmonary bypass circuits: standard circuit (C), biosurfaced circuit (B) and standard circuit containing FUT-175 (F). Each circuit was primed with 500 ml of electrolyte solution and 500 ml of fresh blood. Cardiopulmonary bypass was performed using a roller pump for four hours in two sets of each circuit configuration. Platelet factors (platelet count and beta-thromboglobulin), coagulation factors (thrombin-antithrombin III complex and fibrinopeptide A), fibrinolysis factors (alpha 2-plasmin inhibitor complex and alpha 2-plasmin inhibitor), complement factors (C3a, C4a), free hemoglobin, and granulocyte elastase were measured at the beginning and end of the study. Hemocytograms were measured concurrently. The FUT-175 group showed significantly lower levels of the measured indices than the biosurfaced group in thrombin-antithrombin III complex (7.4 +/- 2.1 vs. 54.9 +/- 38.1 ng/ml), fibrinopeptide A (7.2 +/- 2.0 vs. 20.2 +/- 14.6 ng/ml), beta-thromboglobulin (1940 +/- 250 vs. 2438 +/- 314 ng/ml) and free hemoglobin (25.2 +/- 14.3 vs. 73.8 +/- 18.4 mg/dl). There were no significant differences between Group F and Group B in platelet count, C3a, C4a and granulocyte elastase, although these indices were significantly lower in Groups F and B when compared to Group C.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzamidines↗
PubMed1994

Molecular cloning of lsk, a carboxyl-terminal src kinase (csk) related gene, expressed in leukocytes.

Regulation of the activity of src-family kinases is thought to occur, in part, through the phosphorylation of conserved carboxyl-terminal tyrosine residues. Although the src-family includes several molecules with tissue or cell-type restricted expression, the only kinase implicated in the regulatory phosphorylation of these enzymes is p50csk. Herein we report the molecular cloning of a tissue specific p50csk-related gene. Like p50csk, the deduced protein sequence of this novel cDNA includes a tyrosine kinase catalytic domain, SH2 and SH3 domains, a short amino terminus, and no autophosphorylation or carboxyl-terminal tyrosine residues. Additionally, neither this novel kinase nor p50csk contain the amino-terminal myristoylation site characteristic of the src-family. However, whereas csk is ubiquitously expressed, mRNA corresponding to this novel gene is expressed in brain, natural killer (NK) cells, and activated T cells but not in a variety of other tissues and cell lines. In agreement with the mRNA expression pattern, antiserum reactive with the predicted carboxyl-terminus of the cDNA recognizes a 57 kDa polypeptide in immunoblots of NK cells and PHA-activated T cells. Because of its limited expression and high homology to p50csk, we named this gene lsk; leukocyte carboxyl-terminal src kinase related gene. Identification of a molecule like lsk suggests the existence of tissue specific src-regulatory pathways that function in activated lymphocytes.

Amino Acid Sequence↗
PubMed1994

Establishment of enzyme-linked immunosorbent assays for lipoprotein lipase with newly developed antibodies.

We developed eight new antibodies against lipoprotein lipase (LPL), which included polyclonal antibodies raised against recombinant human LPL produced by transformant cells and two synthetic peptides corresponding to either amino (N)- or carboxy (C)-terminus of human LPL. With these antibodies, we established three effective sandwich enzyme-linked immunosorbent assays (ELISAs) for LPL, which enabled us to examine LPL mass not only in the postheparin plasma from human, rat, mouse, and guinea pig but also in the media and lysates of cultured cells. All of the developed antibodies showed high affinities for LPL, but their binding to LPL did not always influence the lipolytic activity of the enzyme. Interestingly, although the anti-C-terminus antibody should bind to a common epitope of human and mouse LPL, its binding selectively suppressed only human LPL activity. Because amino acid sequence surrounding the epitope is common to both LPLs, difference in the sequence outside the epitope will contribute to the selective suppression of LPL activity by the antibody. Our results also suggested that both termini of LPL would be exposed on the surface of the molecule because they were fully accessible to antibodies and that the N-terminus of LPL would be functionally less important because binding of the anti-N-terminus antibody did not affect human LPL activity. The ELISAs were further utilized to demonstrate the presence of C-terminus truncated LPL protein in the postheparin plasma of an LPL-deficient patient, to map an epitope of the anti-C-terminus antibody within residues 433-436, and to gain insight into the structure-function relationship of the LPL molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[A case of chronic hemorrhagic pyothorax treated by extraperiosteal air plombage method].

A 64-year-old female patient was admitted with severe exertional dypnea. She had undergone left pneumonectomy because of lung tuberculosis at the age of 31. Her chest X-ray showed total opacity of the left hemithorax and mediastinal deviation to the right. The examination of the pleural effusion revealed neither malignant cells nor micro-organisms. She underwent surgery, by extraperiosteal air plombage method, successfully. Five months after the operation, her lung function and chest X-ray improved dramatically and exertional dyspnea was diminished. We conclude that the extraperiosteal air plombage method is a useful technique for patients with chronic hemorrhagic pyothorax.

Chronic Disease↗