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Biomedical subjects

T Matsui

Publications and source records attributed to T Matsui.

At least 73 records · Page 4Linked to original sources
PubMed2002

Fluctuations in plasma macrophage colony-stimulating factor levels during autologous peripheral blood stem cell transplantation for haematologic diseases.

Plasma macrophage colony-stimulating factor (M-CSF) levels were measured in 13 haematologic patients treated with autologous peripheral blood stem cell transplantation (PBSCT). Six of the patients showed an increase in M-CSF peak levels (>3000 pg/ml) during the conditioning and stem cell infusion period. The peak levels of M-CSF in this phase correlated with thrombomodulin levels, indicating the endothelial origin of plasma M-CSF. However, the M-CSF levels were not influenced by TNFalpha. More patients with high M-CSF levels (>5000 pg/ml) suffered from organ failure than those with lower M-CSF levels. These results suggest that high M-CSF levels may correlate with cellular or organ damage in patients treated with PBSCT.

Adult↗
PubMed2002

Lung herniation as an anatomic consequence of pneumonectomy.

BACKGROUND: Pneumonectomy causes an overdistention of the remaining lung as an adaptive response. Excessive lung herniation occasionally causes serious lung dysfunction. METHODS: Twenty-seven patients were selected from 152 patients who underwent pneumonectomy for lung cancer between 1990 and 1998. Complete resections were accomplished; no recurrence was observed for 3 years in these 27 patients. To evaluate the extent of herniation, the Lung Herniation Index (LHI) was developed and defined as the sum of proportions of the maximal transverse length of the remaining lung divided by the transverse length of the thoracic cavity, measured at the level of the aortic arch and the inferior pulmonary vein on chest computed tomography. Sequential changes in LHI were compared between groups. RESULTS: Changes in LHI did not differ between groups delineated on the basis of an FEV1 of 70 % (p = 0.45) and RV/TLC of 40 % (p = 0.99). Patients with a low body mass index (BMI) (< 20 kg/m(2)), however, showed a significantly greater degree of lung herniation than those with a high BMI (> or = 20 kg/m(2)) (p < 0.05). CONCLUSIONS: Concomitant COPD has no effect on lung herniation. Some preventive procedure should be considered for patients with low BMI.

Adult↗
PubMed2002

Non-invasive quantitative monitoring of cerebral blood flow in aneurysmal subarachnoid haemorrhage with 99mTc-ECD.

The purpose of this prospective study was to detect symptomatic cerebral vasospasm in aneurysmal subarachnoid haemorrhage (SAH) by a non-invasive mean cerebral blood flow (mCBF) quantification using 99mTc-ethyl cysteinate dimer. Measurement of mCBF without blood sampling and single photon emission tomography (SPECT) were performed at 1 and 7 days after surgery in 35 consecutive SAH patients, of whom 16 were examined at day 30 as well. A decrease in mCBF of more than 10% on day 7 versus day 1 was considered to indicate vasospasm. On visual interpretation of SPECT, a perfusion decrease which appeared newly on day 7 was considered to indicate vasospasm. In total, nine of 35 patients had cerebral vasospasm confirmed by computed tomography (CT) and/or angiography. The mCBF measurement showed a 77.8% (7/9) sensitivity, a 88.5% (23/26) specificity, a 70.0% (7/10) positive predictive value, and a 92.0% (23/25) negative predictive value. SPECT yielded a 33.3% (3/9) sensitivity, a 73.1% (19/26) specificity, a 30.0% (3/10) positive predictive value, and a 76.0% (19/25) negative predictive value. On SPECT, decreased perfusion was observed in most of the patients at clipping sites, which might represent post-operative transient abnormal perfusion and should not be read as vasospasm. In conclusion, this mCBF measurement is more accurate than visual interpretation of SPECT for detecting vasospasm.

Adult↗
PubMed2002

[MIDCAB in the patient with ischemic heart disease and chronic renal failure].

Our case is a 50-year-old man with angina and chronic renal failure. He underwent double vessel MIDCAB (LITA-LAD and GEA-SVG-RCA). Postoperative course was uneventful and postoperative angiography revealed patent grafts. MIDCAB is thought to be effective for patients who have chronic renal failure, because they are able to resume hemodialysis in early postoperative period for controlling water and electolyte.

Coronary Artery Bypass↗
PubMed2002

[A case of paraffinoma after plombage with spinal paralysis].

A 55-year-old woman was presented with large left-sided chest wall mass and spinal paralysis. She had undergone pleural plombage using paraffin for pulmonary tuberculosis at age 40 years. Thoracotomy was performed and all paraffin was removed. Paraffin provoked granulomatous change (paraffinoma) and invaded to vertebral canal. She remains well at 16 months postoperatively without spinal paralysis.

Female↗
PubMed2001

A comparative study of clinical features between pure checkers and pure washers categorized using a lifetime symptom rating method.

The current study assessed lifetime obsessive-compulsive disorder (OCD) symptoms in 156 Japanese patients with OCD in order to investigate clinical differences between pure lifetime checkers and pure lifetime washers. Fifty subjects (32%), who had no lifetime history of washing or checking compulsions, or who had a principal symptom other than washing or checking compulsions, were initially excluded. The remaining 106 subjects were divided into three groups: 43 pure lifetime washers (W), 33 pure lifetime checkers (C) and 30 subjects who had experienced both checking and washing compulsions over their lifetime (WC). No differences in clinical characteristics were observed between the W and C groups, suggesting that the lifetime washer-checker distinction may not be useful in subtyping OCD. However, subjects in the WC group differed from other subjects in a number of respects including poorer level of insight, more severe psychopathology and global dysfunction. Thus, they can be generally distinguished by more pervasive and severe psychopathological features, and may constitute a valid subgroup of OCD. Further work from a multidimensional perspective is required to verify the clinical significance of a typology based on lifetime symptoms.

Adolescent↗
PubMed2001

XBP1 mRNA is induced by ATF6 and spliced by IRE1 in response to ER stress to produce a highly active transcription factor.

In yeast, the transmembrane protein kinase/endoribonuclease Ire1p activated by endoplasmic reticulum stress cleaves HAC1 mRNA, leading to production of the transcription factor Hac1p that activates the unfolded protein response (UPR). In mammals, no Hac1p counterpart has yet been discovered despite the presence of Ire1p homologs in the endoplasmic reticulum. Instead, the transcription factor ATF6 specific to the mammalian UPR is regulated by intramembrane proteolysis. Here, we identified the transcription factor XBP1, a target of ATF6, as a mammalian substrate of such an unconventional mRNA splicing system and showed that only the spliced form of XBP1 can activate the UPR efficiently. Our results reveal features of the UPR conserved during evolution and clarify the relationship between IRE1- and ATF6-dependent pathways.

Activating Transcription Factor 6↗
PubMed2001

Crystal structure of bitiscetin, a von Willebrand factor-dependent platelet aggregation inducer.

Bitiscetin, a C-type lectin-like protein isolated from the venom of the snake Bitis arientans, promotes the interactions between plasma von Willebrand factor (VWF) and platelet membrane glycoprotein Ib (GPIb) to induce platelet aggregation. We report here the crystal structure of bitiscetin at 2.0 A resolution. The overall fold is similar to those of coagulation factor IX/X-binding protein (IX/X-bp) and flavocetin-A (a GPIb-binding protein), although these three proteins are functionally distinct from one another. The characteristic property determining target recognition is explained mainly by the differences in the surface potential on the central concave surface. A negatively charged patch on the surface of bitiscetin is a candidate for the site of binding to the positively charged surface of the VWF A1 domain, as shown in the case of another platelet aggregation inducer, botrocetin. However, a positively charged patch near the central concave surface is unique for bitiscetin and suggests that it is the binding site for the negatively charged surface of the VWF A3 domain. Thus, the interactions accounting for VWF activation by bitiscetin possibly involve both the A1 and A3 domains of VWF, indicating a specific mechanism of VWF activation by bitiscetin.

Amino Acid Sequence↗
PubMed2001

Relationship between transcardiac extraction of aldosterone and left ventricular remodeling in patients with first acute myocardial infarction: extracting aldosterone through the heart promotes ventricular remodeling after acute myocardial infarction.

OBJECTIVES: The purpose of this study was to evaluate whether plasma aldosterone (ALD) is extracted or produced through the heart in patients with acute myocardial infarction (AMI) and to determine the relationship between transcardiac extraction of plasma ALD and left ventricular (LV) remodeling. BACKGROUND: Although we demonstrated that circulating ALD was extracted through the failing heart and that transcardiac extraction of ALD correlated with LV end-diastolic volume index (LVEDVI) in patients with congestive heart failure, the existence and increase of ALD synthase in the hearts of infarct rats were reported, suggesting cardiac production of ALD in patients with AMI. METHODS: We measured plasma ALD in the aortic root (Ao) and coronary sinus (CS) in 57 consecutive patients who received successful revascularization and enalapril, with first AMI at acute phase and after one month. We also measured plasma procollagen type III aminoterminal peptide (PIIINP) in the CS. RESULTS: Plasma ALD was significantly lower in the CS than it was in the Ao at the acute phase (84.7 +/- 6.3 pg/ml vs. 105.5 +/- 8.0 pg/ml, p < 0.0001). Significant positive correlations exist between the transcardiac gradient of ALD at the acute phase and the LVEDVI at one month. Moreover, the transcardiac gradient of plasma ALD at the acute phase has a significant correlation with plasma PIIINP, a biochemical marker of fibrosis, after one month. Stepwise multivariate analysis showed that transcardiac extraction of plasma ALD at the acute phase had an independent and significant positive relationship with a large LVEDVI after one month. CONCLUSIONS: These results indicate that plasma ALD is extracted through the heart in patients with AMI at the acute phase and that the extracted ALD plays an important role in modulating post-infarct LV remodeling.

Acute Disease↗
PubMed2001

Structural conversion between open and closed forms of radixin: low-angle shadowing electron microscopy.

The function of ERM (ezrin/radixin/moesin) proteins as general cross-linkers between actin filaments and plasma membranes is regulated downstream of Rho, through the transition between active and inactive forms. To directly examine the conformational change between the active and inactive forms of ERM proteins, we applied low-angle rotary-shadowing electron microscopy to the radixin molecules, wild-type, T564A-non-phosphorylated-type, and T564E-phosphorylated-type, since most of the active forms are reportedly stabilized in cells by the C-terminal threonine phosphorylation. As a result, the T564A- and wild-type radixin molecules yielded the globular closed forms, approximately 8-14 nm in diameter, with some striations on their surfaces. In contrast, the T564E-radixin molecules tended to take elongated open forms, in which two globular structures measuring approximately 8 nm and approximately 5 nm in diameter were associated with both ends of the filamentous structures. The filamentous structure took either a approximately 20-25 nm-long straight course or a folded course. Taken together with the biochemical and the crystal structural results obtained to date, the closed and open forms represent the inactive and active forms of radixin as cross-linkers between actin filaments and plasma membranes.

Amino Acid Substitution↗
PubMed2001

Akt activation preserves cardiac function and prevents injury after transient cardiac ischemia in vivo.

BACKGROUND: The serine-threonine kinase Akt is activated by several ligand-receptor systems previously shown to be cardioprotective. Akt activation reduces cardiomyocyte apoptosis in models of transient ischemia. Its role in cardiac dysfunction or infarction, however, remains unclear. METHODS AND RESULTS: We examined the effects of a constitutively active Akt mutant (myr-Akt) in a rat model of cardiac ischemia-reperfusion injury. In vivo gene transfer of myr-Akt reduced infarct size by 64% and the number of apoptotic cells by 84% (P<0.005 for each). Ischemia-reperfusion injury decreased regional cardiac wall thickening as well as the maximal rate of left ventricular pressure rise and fall (+dP/dt and -dP/dt). Akt activation restored regional wall thickening and +dP/dt and -dP/dt to levels seen in sham-operated rats. To better understand this benefit, we examined the effects of myr-Akt on hypoxic cardiomyocyte dysfunction in vitro. myr-Akt prevented hypoxia-induced abnormalities in cardiomyocyte calcium transients and shortening. Akt activation also enhanced sarcolemmal expression of Glut-4 in vivo and increased glucose uptake in vitro to the level seen with insulin treatment. CONCLUSIONS: Akt activation exerts a powerful cardioprotective effect after transient ischemia that probably reflects its ability to both inhibit cardiomyocyte death and improve function of surviving cardiomyocytes. Akt may represent an important nodal target for therapy in ischemic and other heart disease.

Adenoviridae↗
PubMed2001

Mutant mice lacking the cholecystokinin2 receptor show a dopamine-dependent hyperactivity and a behavioral sensitization to morphine.

Cholecystokinin2 (CCK2) receptor-deficient mice were used to analyze the in vivo function of CCK2 receptor and especially the incidence of this gene invalidation on enkephalinergic and dopaminergic systems. Hyperlocomotor activity of CCK2 receptor-deficient mice was suppressed by a selective D2 antagonist but not by a D1 antagonist. Injection of amphetamine induced a hyperlocomotor activity in both groups of mice while mutant mice were less sensitive to cocaine. Administration of 6 mg/kg of morphine once every 2 days for 5 days significantly (P<0.05) enhanced motor activity the last day compared to the first day, only in CCK2 receptor-deficient mice. These results emphasize the role of CCK2 receptors in counteracting the effects of dopaminergic systems and suggest that CCK2 receptor invalidation could lead to a slight behavioral sensitization.

Analgesics, Opioid↗
PubMed2001

Expression of unphosphorylated form of human double-stranded RNA-activated protein kinase in Escherichia coli.

Interferon (IFN)-inducible, double-stranded (dsRNA)-activated protein kinase (PKR) is a key mediator of the antiviral and antiproliferative effects of IFN. PKR is present within cells in a latent state. In response to binding dsRNA, the enzyme becomes activated, causing autophosphorylation and an increase in specific kinase activity. In order to study PKR and its inhibitors, a large amount of the enzyme in its latent, unphosphorylated state is required. When PKR is fused to glutathione S-transferase (GST-PKR) and the fusion protein is expressed in Escherichia coli, the PKR obtained is fully activated by autophosphorylation. Therefore, we have developed an expression plasmid in which both GST-PKR and bacteriophage lambda protein phosphatase (lambda-PPase) genes were placed downstream of a T7 promoter. After induction of expression, unphosphorylated GST-PKR was obtained in good yield, and purified to near homogeneity. The purified enzyme has dsRNA-dependent activation and phosphorylates the translation initiation factor eIF2 alpha. Using the recombinant protein, we analyzed the inhibition mechanisms of two viral inhibitors, vaccinia virus K3L protein and adenovirus virus-associated RNA I (VAI RNA). K3L inhibited both autophosphorylation of PKR and phosphorylation of eIF2 alpha, whereas VAI RNA inhibited only autophosphorylation. The separation of autophosphorylation and catalytic activity shows that the recombinant PKR is useful in analyzing the functions of PKR, its inhibitors, and its regulatory molecules. The coexpression system of protein kinase with lambda-PPase described here will be applicable to obtaining unphosphorylated and unactivated forms of other protein kinases.

Escherichia coli↗
PubMed2001

Crystallization and preliminary crystallographic studies of RhoGDI in complex with the radixin FERM domain.

The Rho guanine nucleotide-dissociation inhibitor (RhoGDI) is a general regulator that forms a complex with the GDP-bound form of Rho-family GTPases and suppresses their activation. The FERM domains of ERM (ezrin/radixin/moesin) proteins bind to RhoGDI and dissociate Rho from RhoGDI. The formation of a complex between RhoGDI and the FERM domain is an important step in the regulatory cycle of Rho activation. In this study, crystals of RhoGDI complexed with the FERM domain of radixin were obtained. The crystals of the binary complex belong to the space group P2(1)2(1)2, with unit-cell parameters a = 130.9 (2), b = 151.2 (2), c = 71.2 (1) A, and contain two protein complexes in the crystallographic asymmetric unit. A 2.9 A resolution data set was collected using synchrotron radiation at SPring-8.

Animals↗
PubMed2001

Crystallographic characterization of the radixin FERM domain bound to the cytoplasmic tail of the adhesion protein ICAM-2.

Radixin is a member of the ERM proteins, which cross-link plasma membranes and actin filaments. The FERM domains located at the N-terminal regions of ERM proteins are responsible for membrane association through direct interactions with the cytoplasmic domains of integral membrane proteins. Here, crystals of the complex between the radixin FERM domain and the full-length cytoplasmic tail (28-residue peptide) of intercellular adhesion molecule 2, ICAM-2, have been obtained. The crystals were found to belong to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 100.44 (9), c = 99.49 (6) A, and contain one complex in the crystallographic asymmetric unit. An intensity data set was collected to a resolution of 2.60 A.

Animals↗
PubMed2001

Exposure of RBL-2H3 mast cells to Ag(+) induces cell degranulation and mediator release.

There is a growing need to understand the impact of environmental sulfhydryl group-reactive heavy metals on the immune system. Here we show that Ag(+) induces mast cell degranulation, as does the aggregation of the high affinity immunoglobulin E receptor (FcepsilonRI). Micromolar quantities of Ag(+) specifically induced degranulation of mast cell model rat basophilic leukemia (RBL-2H3) cells without showing cytotoxicity. The Ag(+)-mediated degranulation could be observed as rapidly as 5 min after the addition of the ions. Ag(+) also induced a rapid change in tyrosine phosphorylation of multiple cellular proteins including the focal adhesion kinase but not Syk kinase. The Syk-selective inhibitor piceatannol and the Src family-selective tyrosine kinase inhibitor PP1 dose-dependently inhibited FcepsilonRI-mediated degranulation, whereas neither compound inhibited the Ag(+)-mediated degranulation. Furthermore, likewise FcepsilonRI aggregation, Ag(+) also induced leukotriene secretion. These results show that Ag(+) activates RBL-2H3 mast cells through a tyrosine phosphorylation-linked mechanism, which is distinct from that involved in FcepsilonRI-mediated activation.

Animals↗