Biomedical subjects

K Matsubara

Publications and source records attributed to K Matsubara.

At least 91 records · Page 5Linked to original sources

PubMed1999

Paradoxical decrease of an adipose-specific protein, adiponectin, in obesity.

We isolated the human adipose-specific and most abundant gene transcript, apM1 (Maeda, K., et al., Biochem. Biophys. Res. Commun. 221, 286-289, 1996). The apM1 gene product was a kind of soluble matrix protein, which we named adiponectin. To quantitate the plasma adiponectin concentration, we have produced monoclonal and polyclonal antibodies for human adiponectin and developed an enzyme-linked immunosorbent assay (ELISA) system. Adiponectin was abundantly present in the plasma of healthy volunteers in the range from 1.9 to 17.0 mg/ml. Plasma concentrations of adiponectin in obese subjects were significantly lower than those in non-obese subjects, although adiponectin is secreted only from adipose tissue. The ELISA system developed in this study will be useful for elucidating the physiological and pathophysiological role of adiponectin in humans.

Adiponectin↗

PubMed1999

Plasma membrane recruitment of RalGDS is critical for Ras-dependent Ral activation.

In COS cells, Ral GDP dissociation stimulator (RalGDS)-induced Ral activation was stimulated by RasG12V or a Rap1/Ras chimera in which the N-terminal region of Rap1 was ligated to the C-terminal region of Ras but not by Rap1G12V or a Ras/Rap1 chimera in which the N-terminal region of Ras was ligated to the C-terminal region of Rap1, although RalGDS interacted with these small GTP-binding proteins. When RasG12V, Ral and the Rap1/Ras chimera were individually expressed in NIH3T3 cells, they localized to the plasma membrane. Rap1Q63E and the Ras/Rap1 chimera were detected in the perinuclear region. When RalGDS was expressed alone, it was abundant in the cytoplasm. When coexpressed with RasG12V or the Rap1/Ras chimera, RalGDS was detected at the plasma membrane, whereas when coexpressed with Rap1Q63E or the Ras/Rap1 chimera, RalGDS was observed in the perinuclear region. RalGDS which was targeted to the plasma membrane by the addition of Ras farnesylation site (RalGDS-CAAX) activated Ral in the absence of RasG12V. Although RalGDS did not stimulate the dissociation of GDP from Ral in the absence of the GTP-bound form of Ras in a reconstitution assay using the liposomes, RalGDS-CAAX could stimulate it without Ras. RasG12V activated Raf-1 when they were coexpressed in Sf9 cells, whereas RasG12V did not affect the RalGDS activity. These results indicate that Ras recruits RalGDS to the plasma membrane and that the translocated RalGDS induces the activation of Ral, but that Rap1 does not activate Ral due to distinct subcellular localization.

3T3 Cells↗

PubMed1999

Axin prevents Wnt-3a-induced accumulation of beta-catenin.

When Axin, a negative regulator of the Wnt signaling pathway, was expressed in COS cells, it coeluted with glycogen synthase kinase-3beta (GSK-3beta), beta-catenin, and adenomatous polyposis coli protein (APC) in a high molecular weight fraction on gel filtration column chromatography. In this fraction, GSK-3beta, beta-catenin, and APC were co-precipitated with Axin. Although beta-catenin was detected in the high molecular weight fraction in L cells on gel filtration column chromatography, addition of conditioned medium expressing Wnt-3a to the cells increased beta-catenin in the low molecular weight fraction. However, Wnt-3a-dependent accumulation of beta-catenin was greatly inhibited in L cells stably expressing Axin. Axin also suppressed Wnt-3a-dependent activation of Tcf-4 which binds to beta-catenin and acts as a transcription factor. These results suggest that Axin forms a complex with GSK-3beta, beta-catenin, and APC, resulting in the stimulation of the degradation of beta-catenin and that Wnt-3a induces the dissociation of beta-catenin from the Axin complex and accumulates beta-catenin.

Adenomatous Polyposis Coli Protein↗

PubMed1999

Severe aplastic anemia associated with human parvovirus B19 infection in a patient without underlying disease.

Human parvovirus B19 (B19 virus) infection is known to induce aplastic crisis in patients with hemolytic anemia. In healthy subjects, B19 infection may sometimes cause mild pancytopenia, but these changes are transient and recovery is spontaneous. We report the first case of aplastic anemia in a previously healthy boy without any underlying diseases, following asymptomatic infection with the B19 virus. Laboratory examination initially showed thrombocytopenia, mild leukopenia in the peripheral blood, and severe hypoplastic bone marrow. Since pancytopenia developed and worsened progressively, immunosuppressive therapy was given, resulting in a complete remission. Despite the lack of an infectious prodrome, serological and histological analysis revealed an underlying infection with the B19 virus. Thus, B19 virus infection must be considered one of the causes of aplastic anemia in patients without underlying hemolytic anemia and an apparent episode of the viral infection.

Adolescent↗

PubMed1999

The effect of cyclic AMP on expression of the major immediate-early genes and replication of human cytomegalovirus in human central nervous system cell lines.

The effect of dibutyryl cyclic AMP (dbcAMP) on interaction of human cytomegalovirus (HCMV) with human central nervous system cell lines was examined. Activation of the major immediate-early (IE) promoter (MIEP) of HCMV by dbcAMP was observed in human neuroblastoma IMR-32 cells, but not in glioma 118MGC and astrocytoma U373-MG cells. The 19 bp repeat element in the enhancer of the MIEP was most likely to be the cis-element that responded to dbcAMP in IMR-32 cells as we expected. In IMR-32 cells activation of the MIEP led to enhanced synthesis of the major IE proteins and infectious HCMV.

Astrocytoma↗

PubMed1999

Abnormal course, abnormal flow, and systolic compression of the septal perforator associated with impaired myocardial perfusion in hypertrophic cardiomyopathy.

BACKGROUND: The septal perforators in hypertrophic cardiomyopathy (HCM) show systolic compression. The compression is thought to be related to the malpositioned septal perforators, but its relation to the development of myocardial ischemia remains controversial. METHODS: We examined echocardiographically the blood flow and course of the major septal perforator in 142 consecutive patients with HCM; of these, 94 underwent coronary angiography to assess systolic compression of the septal perforators and 110 had thallium-201 scintigraphy. We then analyzed the relation of the findings in comparison with the results in 15 patients with valvular aortic stenosis (AS). RESULTS: The major septal perforator was visualized in 82 patients with HCM and in 8 patients with AS. The visualization did not depend on the pressure gradient between the left ventricle and aorta in the HCM patients, but did in the AS patients. In AS the perforator always showed a normal course near to, and convexly toward, the right ventricle. In 71 of the 82 HCM patients, the perforator was distant from the right-sided endocardium of the ventricular septum and often convex toward the left. The greater the leftward deviation, the higher was the grade of compression. In 48 of the 82 patients with HCM and in all of the 8 patients with AS who showed the flow signal, the septal perforator showed systolic retrograde flow; in the patients with HCM there was a significant correlation (r = 0.54, P <.05) between the peak velocity and the degree of leftward deviation. Furthermore, higher degrees of the leftward deviation and higher degrees of the systolic compression of the major perforator were each associated with a higher incidence of exercise-induced defect of thallium-201. CONCLUSION: The echocardiographic, angiographic, and scintigraphic findings in HCM may be closely related to one another. We speculate that the series of abnormalities is initiated by a high intramural pressure and impedance on the septal perforators due to their deviation toward the left.

Adult↗

PubMed1999

A fibrinolytic enzyme from a marine green alga, Codium latum.

A fibrinolytic enzyme was isolated from a marine green alga, Codium latum, and designated C. latum protease (CLP). It also had fibrinogenolytic activity, hydrolyzing A alpha, B beta and gamma chains with preference in this order. As CLP hydrolyzed oxidized insulin B chain at position Arg22-Gly23, and the peptide map of lysozyme digested with CLP was similar to that with trypsin, CLP would be expected to have a high substrate specificity, similar to that of trypsin. Protease activity peaked at pH 10, and was completely inhibited by diisopropyl fluorophosphate (DFP). Therefore, we conclude that CLP is a trypsin-like serine protease.

Animals↗

PubMed1999

Degradation of pectic substances by two pectate lyases from a human intestinal bacterium, Clostridium butyricum-beijerinckii group.

Clostridium butyricum-beijerinckii group, an anaerobic human intestinal bacterium, produced exo-pectate lyase, endo-pectate lyase, and pectin methylesterase, but not polygalacturonase. The production of the two pectate lyases was strongly influenced by the composition of the carbon sources added to the medium. The enzymes secreted by the bacterium into the human large intestine cooperatively digested pectic substances, producing mainly 4,5-unsaturated digalacturonic acid with the participation of the pectin methylesterase. The findings suggest that in the human intestine the bacterium contributes to the digestion of ingested pectic substances.

Journal Article↗

PubMed1999

Age-related changes in thrombopoietin in children: reference interval for serum thrombopoietin levels.

We studied thrombopoietin (TPO, Mpl ligand) values using a sensitive ELISA in 254 serum samples obtained from disease-free children and adult volunteers. TPO was detected in all samples, and its values ranged widely from 0.25 to 9.18 fmol/ml. When analysed by dividing the subjects into 11 age groups, the mean TPO levels from birth to 1 month of age were increased (3.73-5.92 fmol/ml). The highest values were found 2 d after birth; TPO levels then gradually decreased to adult levels (0.83 fmol/ml). The relationship between TPO values and platelet counts was not significant in all subjects (r = 0.27) or in children alone (r = 0.12). In children > 1 month of age a 95% reference interval for serum TPO values was determined from 0.58 to 3.27 fmol/ml. A significant correlation was found between TPO values in serum and plasma; serum TPO values = -0.257 + 4.039 x plasma TPO values (r = 0.951, P < 0.001, n = 22). This study is the first to report age-dependent changes in blood TPO levels throughout child development. Serum TPO values were significantly high up to 1 month of age and were correlated with plasma TPO levels.

Adolescent↗

PubMed1999

Characterization of TSH-positive cells in foetal rat pars tuberalis that fail to express Pit-1 factor and thyroid hormone beta2 receptors.

The thyroid stimulating hormone (TSH)-immunoreactive cells (TSH cells) in the pars tuberalis (PT-TSH cell) of the male rat pituitary gland show an intense spot-like TSH immunoreaction in the paranuclear cytoplasm. However, the ontogenic origin and characteristics of these spot-like stained PT-TSH cells remain to be elucidated. The present study was designed to investigate the distribution and characteristics of PT-TSH cells in the foetal and adult rat pituitary by immunostaining for Pit-1 factor and thyroid hormone receptors (TRs) and reverse transcriptase-polymerase chain reaction (RT-PCR). TSH cells first appeared in the PT at 15.5 days of gestation and were either stained diffusely throughout the cytoplasm or displayed a strongly stained, spotty appearance in the paranuclear region. By 15.5 days of gestation, the rostral part of the PT consisted of columnar epithelium, in which TSH immunoreactivity was spot-like in the apical region of cytoplasm corresponding to the Golgi apparatus. At the 16.5 days of gestation, TSH cells were present in the pars distalis (PD); however, the cells were mostly larger and polygonal with strong staining throughout the cytoplasm. These differences between the PT and PD were retained throughout foetal and neonatal rat development. The TSH cells in the PD of the adult or gestational rat were observed to contain Pit-1 factor by double immunostaining. However, TSH cells in the PT lacked Pit-1 factor. RT-PCR confirmed the absence of Pit-1 and TRbeta2 mRNA in the PT of the adult and late gestation rat pituitary gland. These results suggest that apparently distinct types of TSH cells in the PT develop independently from TSH cells in the PD.

Animals↗

PubMed1999

Expression profile of active genes in mouse lymph node high endothelial cells.

High endothelial venules (HEV) allow rapid and selective lymphocyte trafficking from the blood into secondary lymphoid tissues. Here we report the expression profile of active genes in mouse high endothelial cells (HEC). HEC were first purified from mouse lymph nodes (LN) by magnetic cell sorting with MECA-79 mAb and a 3'-directed cDNA library that faithfully represents the composition of mRNA was constructed. A total of 1495 cDNA sequences were obtained from randomly selected clones. Based on their sequence identity, they were grouped into 754 different species [gene signatures (GS)] of which 335 GS were identified in GenBank. Among the previously identified genes, expression of several endothelial cell surface molecules including endoglin and ICAM-1 was detected in HEC. Comparison of the gene expression profile with that of purified CD31(+) flat endothelial cells identified several molecules, such as KC chemokine and Duffy antigen/receptor for chemokines, that are known to be selectively expressed in activated endothelial cells or post-capillary venules. Interestingly, mac25/TAF, which is known to be expressed specifically in tumor vessels and implicated in the regulation of cell adhesion, was highly and selectively expressed in HEC in mouse LN, suggesting that it may participate in regulating HEC-specific functions. Comparison with the expression profiles obtained from 35 different cell types showed at least 22 GS that were apparently specific to HEC. Our results illustrate the expression differences between HEC and CD31(+) flat endothelial cells, and will be useful for the identification and characterization of genes specific for HEC.

Animals↗

PubMed1999

Leukocyte function-associated antigen-1 expression on decidual natural killer cells in patients with early pregnancy loss.

A large number of CD56(bright) natural killer (NK) cells, which comprise a very small fraction of peripheral blood lymphocytes, appear in the endometrium during the late secretory phase and early pregnancy. These cells are thought to immunologically maintain or inhibit pregnancy. However, the details regarding their contribution to the immuno-elimination systems of embryonic cells or decidual stromal cells remain unclear. Recently, leukocyte function-associated antigen-1 (LFA-1) was shown to play a critical role in the regulation of NK cytolysis in peripheral blood lymphocytes. We speculated that LFA-1 on the decidual CD56(bright) NK may be involved in the regulation of pregnancy. The expression of LFA-1 on the decidual CD56(bright) NK cells was analysed using flow cytometry with fluorescent monoclonal antibodies; CD56 (NKH1), CD16 (Fcg-R3) and CD11a (LFA-1 alpha-chain). In comparison with non-pregnant endometrium during the late secretory phase, the subpopulation of CD56(bright)CD16(-) cells in decidual lymphocytes was significantly increased during normal pregnancy, but was less than that in early pregnancy loss (P < 0.05). Furthermore, the number of CD56(bright) NK cells expressing LFA-1 was significantly higher in early pregnancy loss, and the late secretory phase, than during normal pregnancy (P < 0.05). Our results indicate that up-regulation of LFA-1 on CD56(bright) NK cells is related to spontaneous abortion or the onset of menstruation.

Abortion, Spontaneous↗

PubMed1999

Metabolic studies of [18F-alpha-methyl]tyrosine in mice bearing colorectal carcinoma LS-180.

Brain and tumor uptake of [18F-alpha-methyl]tyrosine (18F-AMT) and the incorporation into each of four fractions (lipid, RNA, DNA and protein) were investigated in mice bearing LS180 colorectal carcinoma. Homogenized tissues were analyzed by the fractionation method into an acid-soluble fraction (ASF) and an acid-precipitable fraction (APF). The APF was further investigated to assess the incorporation of 18F-AMT into each fraction. Incorporation into four fractions of brain and tumor at 60 min post-injection was 20 and 12%, respectively; 10% of the activity was incorporated to lipid in brain and 5% in tumor. There was 5, 2 and 2% incorporation with RNA, DNA and protein, respectively. Metabolites in ASF were analyzed by high-performance liquid chromatography and thin-layer chromatography. There was only one radioactive peak, which corresponded to 18F-AMT. The incorporation of 18F-AMT into lipid was twice that of 18F-AMT in tumor. The uptake of 18F-AMT in tissues was rapid and accomplished before 30 min, and then slowly diffused in blood. These results implied that 18F-AMT was metabolized to protein to only a small extent and trapped as intact 18F-AMT in cells up to 60 min. We conclude that 18F-AMT is a promising tracer for tumor imaging and quantification of the transport rate using two-compartment models.

Animals↗

PubMed1999

Gene mutations of K-ras in gallbladder mucosae and gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct.

OBJECTIVE: In this study, we examined the mutational spectrum of K-ras in cases of gallbladder and gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct (AJPBD). METHODS: We examined 35 gallbladders with AJPBD (20 with hyperplasia, 15 with carcinoma) and 38 gallbladders without AJPBD (four normal gallbladders, four with hyperplasia, six with adenoma, 24 with carcinoma). Polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and direct sequencing were performed to detect mutations in codon 12 or 13 of K-ras. RESULTS: In the cases with AJPBD, the prevalences of K-ras mutation were 15% (3/20) in hyperplasia, 60% (6/10) in stage I carcinoma, and 100% (5/5) in stage II-IV carcinoma. In the cases without AJPBD, the prevalences of K-ras mutation were 0% (0/4) in normal gallbladder, 0% (0/4) in hyperplasia, 17% (1/6) in adenoma, 7% (1/16) in stage I carcinoma, and 38% (3/8) in stage II-IV carcinoma. Prevalences of K-ras mutation in hyperplasia and carcinoma with AJPBD were greater than those without AJPBD (p < 0.05). The point mutation of GGT to GAT in codon 12 was frequently observed in the cases with AJPBD. CONCLUSION: These results suggest that the specific K-ras mutation in codon 12 (GGT to GAT) may contribute to the early stage of carcinogenesis in the gallbladder with AJPBD.

Adenoma↗

PubMed1999

The influence of the maternal heart rate on the uterine artery pulsatility index in the pregnant ewe.

We investigated the influence of the maternal heart rate on the uterine artery pulsatility index in pregnant ewes. We used an external pacemaker to alter the heart rate of 5 pregnant ewes at 16-17 weeks of pregnancy and examined the effect of changes in the maternal heart rate on the uterine artery flow velocity waveforms and the pulsatility index, as determined by Doppler velocimetry. The uterine artery pulsatility index showed a significant negative correlation with the maternal heart rate. There were no significant changes in other hemodynamic parameters. The maternal heart rate had a significant influence on the uterine artery pulsatility index.

Animals↗

PubMed1999

Fetal compromise assessed by Doppler ultrasound of venous flow in pregnancy-induced hypertension.

The purpose of this study was to determine the change of venous flow patterns in the inferior vena cava of fetuses in pregnancy-induced hypertension (PIH). We studied 80 normal pregnant women and 46 pregnant women with PIH and their fetuses. We determined the pulsatility index (PI) for arterial vessels, the ratio of peak flow velocities in early diastole and late diastole (E/A) in atrioventricular valves, and the preload index for the inferior vena cava. Twelve of the 46 PIH women showed an umbilical artery PI higher than the 95th percentile in normal pregnant women. Five of them demonstrated a decreased middle cerebral artery PI. Three of the 5 had an increased mitral E/A. Two of them had a decreased tricuspid E/A, an increased preload index, and a poor prognosis. An increased preload index suggests severe compromise in fetuses with a redistribution of arterial and intracardiac blood flow.

Adult↗

PubMed1999

Effect of histamine H2-receptor antagonist on the phosphorus-binding abilities of calcium carbonate and calcium lactate in hemodialysis patients.

The effect of histamine H2-receptor antagonist (famotidine) on the phosphorus-binding abilities of calcium carbonate and calcium lactate were examined in 13 chronic hemodialysis patients. In seven patients receiving calcium carbonate, famotidine (20 mg/d) was given because of gastroduodenal disorders, and calcium carbonate was replaced with calcium lactate as a phosphorus binder after 4 wk of treatment with famotidine. With the 4-wk administration of famotidine accompanied by calcium carbonate, the serum phosphorus level increased from 6.3+/-0.9 to 7.1+/-0.5 mg/dl (P<0.05). However, with the substitution of calcium lactate, the serum phosphorus level decreased significantly when compared to that before substitution (6.3+/-0.2 and 6.0+/-0.9 mg/dl after 4 and 8 wk of substitution, respectively), despite continued administration of famotidine. Serum calcium, creatinine, alkaline phosphatase, high sensitive parathyroid hormone, blood urea nitrogen, arterial blood pH, and bicarbonate were not significantly altered during the trial period. In six control patients treated with calcium carbonate alone, there were no statistical changes in serum calcium and phosphorus levels after substitution of calcium lactate for calcium carbonate. These results suggest that famotidine significantly affects the phosphorus-binding ability of calcium carbonate, but not that of calcium lactate. A careful observation of changes in the serum phosphorus level should be required in hemodialysis patients receiving calcium carbonate and histamine H2-receptor antagonists. Calcium lactate may be useful as a phosphorus binder in such hemodialysis patients.

Adult↗

PubMed1999

Concentrations of serum granulocyte-colony-stimulating factor in normal pregnancy and preeclampsia.

OBJECTIVE: In order to elucidate the potential role of granulocyte-colony-stimulating factor (G-CSF) during the course of normal pregnancy and preeclampsia, we measured the serum concentrations of G-CSF in both normal pregnant women and preeclamptic patients. METHODS: Sera of 10 nonpregnant women, 34 normal pregnant women (n = 10, first trimester; n = 10, second trimester; n = 14, third trimester), 10 postpartum women, 10 mild preeclamptic patients, and 10 severe preeclamptic patients were collected. The serum concentrations of G-CSF were measured by enzyme immunoassay. RESULTS: The serum level of G-CSF in normal pregnant women (third trimester: 38.3 +/- 15.3 pg/mL; mean +/- SD) was significantly increased when compared with the levels observed in nonpregnant women (20.3 +/- 10.1 pg/mL, p < 0.05), which was similar to the G-CSF concentrations in postpartum subjects (20.7 +/- 9.1 pg/mL). The mild and severe preeclamptic patients showed significantly higher levels of G-CSF (56.9 +/- 18.8 pg/mL, p < 0.05; 73.2 +/- 30.4 pg/mL, p < 0.0001, respectively) than those noted in the third trimester women. The preeclamptic patients who presented with edema had greater (p < 0.01) serum levels of G-CSF (75.5 +/- 25.0 pg/mL) compared with nonedematous patients (44.7 +/- 14.9 pg/mL). The serum levels of G-CSF significantly correlated with both weight gain (p < 0.05), diastolic blood pressure (p < 0.01), and systolic blood pressure (p < 0.01), but not with white blood cell counts. CONCLUSION: Serum concentrations of G-CSF are increased in normal and, even more so, in preeclamptic pregnancies. Because there was no relationship between serum G-CSF concentration and the number of leukocytes, G-CSF might act not to promote the physiological leukocytosis of pregnancy, but to stimulate the function of leukocytes such as phagocytosis. Moreover, it might be that G-CSF plays important roles in the activation of granulocytes or vascular endothelial injury, which are considered to be important pathological conditions in the development of preeclampsia.

Adult↗