PubMed Health⌕ Search

Biomedical subjects

Tetsuro Sugiura

Publications and source records attributed to Tetsuro Sugiura.

At least 19 recordsLinked to original sources

Acetylcholine inhibits the hypoxia-induced reduction of connexin43 protein in rat cardiomyocytes.

In a recent study, we demonstrated that vagal stimulation increases the survival of rats with myocardial infarction by inhibiting lethal arrhythmia through regulation of connexin43 (Cx43). However, the precise mechanisms for this effect remain to be elucidated. To investigate these mechanisms and the signal transduction for gap junction regulation, we investigated the effect of acetylcholine (ACh), a parasympathetic nerve system neurotransmitter, on the gap junction component Cx43 using H9c2 cells. When cells were subjected to hypoxia, the total Cx43 protein level was decreased. In contrast, pretreatment with ACh inhibited this effect. To investigate the signal transduction, cells were pretreated with L-NAME, a nitric oxide synthase inhibitor, followed by ACh and hypoxia. L-NAME was found to suppress the ACh effect. However, a NO donor, SNAP, partially inhibited the hypoxia-induced reduction in Cx43. To delineate the mechanisms of the decrease in Cx43 under hypoxia, cells were pretreated with MG132, a proteasome inhibitor. Proteasome inhibition produced a striking recovery of the decrease in the total Cx43 protein level under hypoxia. However, cotreatment with MG132 and ACh did not produce any further increase in the total Cx43 protein level. Functional studies using ACh or okadaic acid, a phosphatase inhibitor, revealed that both reagents inhibited the decrease in the dye transfer induced by hypoxia. These results suggest that ACh is responsible for restoring the decrease in the Cx43 protein level, resulting in functional activation of gap junctions.

Acetylcholine↗

Helicobacter pylori CagA status associated with gastric cancer incidence rate variability in Costa Rican regions.

BACKGROUND: We evaluated several risk factors for gastric cancer in Costa Rican regions having contrasting gastric cancer incidence rates, despite the small dimensions of the country. METHODS: A total of 180 dyspeptic patients were classified into two groups according to the gastric cancer incidence (GCI) rate in their Costa Rican region: group A, with a high GCI rate (n = 91) and group B, with a low GCI rate (n = 89). Helicobacter pylori infection was detected by rapid urease test, Gram staining, and histological observation. Antral and corpus specimens were obtained to assess the grade of inflammation, topography of gastritis, gastric atrophy, and intestinal metaplasia by histological examination. Serum CagA antibody was measured by an antigen-specific enzyme-linked immunosorbent assay. RESULTS: There was no significant difference in H. pylori prevalence between groups A (73%) and B (63%); however, serum CagA antibody was more frequently detected in group A (79%) than in group B (54%) [P = 0.02; odds ratio (OR), 2.68]. Among patients under 60 years of age, serum CagA antibody was even more frequently detected in group A (81%) than in group B (49%) (P < 0.01; OR, 4.50). The prevalence of corpus-predominant gastritis, atrophic gastritis, and moderate/severe grades of neutrophilic infiltration was higher in serum CagA antibody-positive patients than in CagA antibody-negative patients (P = 0.003, 0.04, and 0.002, respectively). CONCLUSIONS: Infection with H. pylori possessing the cagA gene is associated with the development of severe gastric damage such as gastric atrophy, leading to gastric cancer, and probably influences the differences in GCI between Costa Rican regions.

Adult↗

The effect of verapamil on the restoration of myocardial perfusion and functional recovery in patients with angiographic no-reflow after primary percutaneous coronary intervention.

OBJECTIVE: Angiographic thrombolysis in myocardial infarction (TIMI) flow grade < or = 2 after primary percutaneous coronary intervention (PCI), defined as angiographic no-reflow, predicts poor functional recovery in patients with acute myocardial infarction. We investigated the effect of verapamil on the restoration of myocardial perfusion and functional recovery in patients with angiographic no-reflow after PCI. METHODS: 99mTc tetrofosmin single photon emission computed tomographic (SPECT) imaging was performed (before, immediately after and 1 month after PCI) in 101 consecutive patients with acute myocardial infarction. The defect score was calculated as the sum of perfusion defect in a 13-segment model (scores of 3, complete defect to 0, normal perfusion). The asynergic score, defined as the number of asynergic segments, was assessed by echocardiography before and 1 month later. Multiple logistic regression analysis was performed to elucidate the effect of verapamil administration. RESULTS: Of 101 patients, 32 (31%) had angiographic no-reflow and were divided into two groups: 18 patients with verapamil (group 1) and 14 patients without verapamil (group 2). Sixty-nine patients had TIMI grade 3 reflow after PCI (group 3). The change in the defect score 1 month after PCI in group 1 was significantly larger than that in group 2 (P = 0.003). The asynergic score improved more at 1 month in group 1 compared to that in group 2 (P = 0.007). Moreover, logistic regression analysis revealed that TIMI grade reflow < or = 2 after PCI (P = 0.04, OR = 5.51), the defect score before PCI (P = 0.03, OR = 1.15), the asynergic score before PCI (P = 0.01, OR = 0.64) and the administration of verapamil (P = 0.002, OR = 22.4) were independently associated with successful myocardial reperfusion immediately after PCI. CONCLUSIONS: Intracoronary verapamil restored myocardial perfusion in patients with angiographic no-reflow after PCI and lead to better functional recovery after acute myocardial infarction.

Aged↗

Cell elongation and cell death of helicobacter pylori is modulated by the disruption of cdrA (cell division-related gene A).

The cell division-related gene A (cdrA) of Helicobacter pylori is dispensable in vivo and unique in having a repressive role on cell division and long-term survival. To clarify its role, comparisons of the wildtype HPK5 and isogenic cdrA-disrupted mutant HPKT510 were examined by ultrastructural morphology, PBP profiles, and susceptibility to beta-lactam antibiotics during long-term cultivation. Ultrastructural analyses revealed that the shorter rods of HPKT510 had a slightly wider periplasmic space between the inner and the outer membrane than those of HPK5. Cell division of HPKT510 cells was complete even under high-salt conditions in which HPK5 cells became filamentous due to inhibition of division. The filamentous HPK5 cells constructed an inner membrane without a cell wall at the presumed division site. After 4 days of cultivation (the late stationary phase), most of the HPK5 cells turned into ghosts and aggregates, while some of the HPKT510 cells remained as curved rods, which coincided with the results of cell viability. HPKT510 cells became resistant to ampicillin killing compared to HPK5 cells, although their minimum inhibitory concentrations (MICs) and PBP profiles were not significantly different. These results suggest that the cdrA product represses cell division via inhibiting cell wall synthesis at division site. During infection in both mice and humans, inactivation of cdrA eventually gains biological aspects such as increased viability, long-term survival and tolerance to antibiotics and high-salt condition, which might enhance a persistent infection.

Anti-Bacterial Agents↗

[Holter electrocardiogram network system to support regional medical care].

To support regional medical care, the clinical laboratory of Kochi Medical School Hospital developed a Holter electrocardiogram (ECG) network system with regional hospitals. Holter ECG data are received from the regional hospitals and reports are sent back using the Internet. When Holter ECG shows recordings which need immediate attention such as ventricular tachycardia or ischemic ST changes, a medical technologist contacts the regional hospital immediately. The reports are checked and approved by a cardiologist who also gives advice to doctors concerning the treatment of patients. By using the medical facilities and personnel of the university hospital, this system provides rapid and appropriate medical care for patients in our area. Moreover, improvement in the skills and knowledge of the technologists in our hospital was achieved using the Holter ECG network system.

Community Health Services↗

Hypoxia-inducible factor-1alpha is involved in the attenuation of experimentally induced rat glomerulonephritis.

BACKGROUND/AIM: Among various kidney disease models, there are few rat glomerulonephritis (GN) models that develop in a short time, and with mainly glomerular lesions. Hypoxia-inducible factor (HIF)-1alpha is a transcriptional factor that induces genes supporting cell survival, but the involvement of HIF-1alpha in attenuating the progression of GN remains to be elucidated. We developed a new model of rat GN by coadministration of angiotensin II (AII) with Habu snake venom (HV) and investigated whether HIF-1alpha is involved in renal protection. METHODS: Male Wistar rats were unilaterally nephrectomized on day 1, and divided into 4 groups on day 0; N group (no treatment), HV group, A group (AII), and H+A group (HV and AII). To preinduce HIF-1alpha, cobalt chloride (CoCl2) was injected twice before injections of HV and AII in 11 rats. RESULTS: GN was detected only in the H+A group; observed first on day 2 and aggravated thereafter. HIF-1alpha was expressed in the glomeruli and renal tubules in the A and H+A groups. In the H+A group, GN was remarkably reduced by CoCl2 pretreatment (44.9 to 12.2%, p < 0.01). CONCLUSION: Both HV and AII were critical for the development of GN, and HIF-1alpha remarkably attenuated the progression of GN.

Angiotensin II↗

Effect of serum albumin on QRS wave amplitude in patients free of heart disease.

We studied 193 patients free of heart disease to determine the relation between QRS amplitude and serum albumin. Although there were no significant differences in echocardiographic indexes between the 2 groups, albumin (35.1 +/- 4.3 vs 40.1 +/- 3.2 g/L) and colloid osmotic pressure (21 +/- 4 vs 24 +/- 3 mm Hg) were significantly lower in patients with low voltages compared with those without. Moreover, there was a good relation (r = 0.78) between change in QRS amplitude and change in albumin concentration.

Adult↗

Scintigraphic prediction of left ventricular functional recovery early after primary coronary angioplasty using single-injection quantitative electrocardiographic gated SPECT.

OBJECTIVE: The clinical usefulness of characterizing reperfused myocardium by perfusion/thickening assessment using electrocardiographic gated single photon emission computed tomography (SPECT) has not been investigated. We evaluated whether single-injection gated SPECT with 99mTc tetrofosmin early after primary percutaneous coronary intervention (PCI) can predict left ventricular (LV) functional recovery. METHODS: Gated SPECT was performed 3 days after primary PCI in 45 patients with acute myocardial infarction and revascularized segments were classified into perfusion/thickening mismatched segments, matched normal and matched abnormal segments. Gated SPECT was repeated 3 months later to evaluate the changes in LV ejection fraction (deltaLVEF). RESULTS: Among 332 revascularized segments, there were 83 mismatched segments, 163 matched abnormal segments and 86 matched normal segments. In all the patients, LVEF increased significantly from 3 days to 3 months after primary PCI (52+/-13 to 57+/-14%, P<0.0001). Patients were divided into two groups according to deltaLVEF: 24 patients with LV functional recovery (deltaLVEF > or = 5%) and 21 patients without LV functional recovery. The number of mismatched segments in patients with LV functional recovery was significantly greater than that in patients without (2.7+/-1.7 vs. 0.8+/-1.4, P<0.0003) despite no differences in the number of matched abnormal and matched normal segments. There was a significant correlation between deltaLVEF and the number of mismatched segments (r=0.56, P<0.0001) and LVEF at 3 months after primary PCI was related to the number of matched abnormal segments (r=-0.78, P<0.0001). CONCLUSION: Single-injection gated SPECT early after primary PCI can predict LV functional recovery.

Angioplasty, Balloon, Coronary↗

Cardiovascular adaptations to exercise training after uncomplicated acute myocardial infarction.

OBJECTIVE: This study examined the cardiovascular adaptations of an exercise training program and evaluated the role of peripheral vasodilator capacity in contributing to these adaptations after myocardial infarction. DESIGN: A total of 44 consecutive patients with uncomplicated myocardial infarction underwent 3 wks of exercise training. Controls (n = 12) with comparable myocardial infarction were selected from our database and were restricted to a program with minimal activity. All patients performed cardiopulmonary exercise testing with hemodynamic measurements. Forearm and calf reactive hyperemic flow were measured by venous occlusive plethysmography as indices of peripheral vasodilator capacity. RESULTS: Despite no change in arteriovenous oxygen difference at peak exercise after training, training resulted in significant increases in oxygen consumption, cardiac output, and stroke volume and a significant decrease in systemic vascular resistance at peak exercise (overall, P < 0.05). Calf reactive hyperemic flow increased significantly after training (P < 0.001), but forearm reactive hyperemic flow did not. Furthermore, increase in calf reactive hyperemic flow after training had a positive correlation with increases in peak cardiac output, stroke volume, and oxygen consumption after training and an inverse correlation with peak systemic vascular resistance. CONCLUSIONS: Exercise training improved exercise tolerance by improving hemodynamic responses to exercise after myocardial infarction. This improved exercise performance was linked to a training-induced increase in calf vasodilator capacity.

Adaptation, Physiological↗

Iodine 123-metaiodobenzylguanidine imaging reflect generalized sympathetic activation in patients with left ventricular dysfunction.

BACKGROUND: Iodine 123-metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. To determine the role of MIBG imaging as a measure of generalized sympathetic nerve activity, MIBG imaging was evaluated with muscle sympathetic nerve activity (MSNA) and plasma norepinephrine (noradrenaline) level in patients with old myocardial infarction. METHODS: Myocardial MIBG scintigraphy, MSNA and plasma norepinephrine measurement were performed within 3 days in 35 patients with old myocardial infarction. Patients were divided into three groups according to their ejection fraction (EF); preserved (EF > or = 50%, 12 patients), intermediate (35% < EF < 50%, 13 patients), or depressed (EF < or = 35%, 10 patients). The heart to mediastinum (H/M) ratio was obtained 4 h after tracer injection from the chest anterior view image. MIBG washout rate was calculated from the early and delayed images. MSNA was recorded by microneurography. RESULTS: Plasma norepinephrine level had weak negative correlations with early H/M ratio (r = 0.37, P<0.05) and delayed H/M ratio (r = 0.33, P<0.05), and a positive correlation with MIBG washout rate (r = 0.54, P<0.01). MSNA had weak negative correlations with early H/M ratio (r = 0.51, P<0.05) and delayed H/M ratio (r = 0.52, P<0.05). However, a strong correlation was found between MSNA and MIBG washout rate (r = 0.88, P<0.001). Despite no significant differences in plasma norepinephrine level and H/M ratio, patients with intermediate and depressed EF had higher MIBG washout rate and MSNA compared with those with preserved EF. CONCLUSIONS: Increased in cardiac sympathetic nerve activity was associated with augmented sympathetic outflow of the skeletal muscle and hence, MIBG washout rate allow the assessment of general sympathetic nerve activity.

3-Iodobenzylguanidine↗

The effect of residential exercise training on baroreflex control of heart rate and sympathetic nerve activity in patients with acute myocardial infarction.

STUDY OBJECTIVES: Exercise training has been shown to favorably affect the prognosis after acute myocardial infarction (AMI), but the mechanisms of such favorable effects remain speculative. The aim of this study was to determine whether exercise training improves baroreflex control of heart rate and muscle sympathetic nerve activity (MSNA) in patients with AMI. DESIGN: Prospective randomized clinical study. PARTICIPANTS: Thirty patients with an uncomplicated AMI were randomized into trained or untrained groups. Arterial BP, heart rate, and MSNA were measured at rest, and during baroreceptor stimulation (phenylephrine infusion) and baroreceptor deactivation (nitroprusside infusion). These measurements were performed at baseline and after 4 weeks of exercise training. MEASUREMENTS AND RESULTS: Peak oxygen uptake increased significantly (12.3 +/- 10.7% [mean +/- SD]) with exercise training. Resting MSNA reduced from 34 +/- 12 to 27 +/- 8 bursts/min in the trained group but not in the untrained group. Arterial baroreflex sensitivity (BRS) [from 8.9 +/- 3.0 to 10.3 +/- 3.0 ms/mm Hg, p < 0.05] and MSNA response to baroreceptor stimulation (change of integrated MSNA from - 47 +/- 23 to - 70 +/- 21%, p < 0.01) improved significantly in the trained group, but not in the untrained group. Despite baroreceptor deactivation improving MSNA response in both groups, there was no significant difference between the two groups. CONCLUSIONS: Exercise training increased arterial BRS and decreased sympathetic nerve traffic after AMI, which indicate that the sympathoinhibitory effect of exercise training may, at least in part, contribute to the beneficial effect of exercise training in patients with AMI.

Baroreflex↗

Clinical factors associated with persistent pericardial effusion after successful primary coronary angioplasty.

STUDY OBJECTIVE: To evaluate the incidence and clinical factors related to the persistence of infarct-associated pericardial effusion (PE) after primary angioplasty. DESIGN: Consecutive case-series analysis. SETTING: Coronary care unit in a university hospital. PATIENTS: Three hundred ninety-one consecutive patients with acute myocardial infarction (AMI) who underwent successful primary percutaneous transluminal coronary angioplasty (PTCA) at hospital admission. INTERVENTIONS: Coronary angiography and primary PTCA on hospital admission and serial echocardiography. MEASUREMENTS AND RESULTS: The status of coronary flow before and after primary PTCA was evaluated by coronary angiography at hospital admission, while PE was studied by echocardiography within 24 h of admission and 1 month after the onset of AMI. PE was present in the acute phase in 76 patients (19%), and patients with PE had a significantly higher incidence of in-hospital death than those without PE (11% vs 2%, p < 0.001). Among 68 patients who had PE in the acute phase and underwent echocardiography 1 month later, PE persisted to 1 month after the onset of AMI (persistent PE) in 26 patients (38%). Patients with persistent PE had a significantly higher incidence of pericardial rub (p = 0.010), Killip class > 1 (p = 0.025), no reflow after PTCA (p = 0.026), lower incidence of collaterals (p = 0.024), and tended to have higher peak creatine kinase (CK) [p = 0.05] levels than those with transient PE. When five variables (peak CK, collaterals, no reflow, pericardial rub, and Killip class > 1) were used in the multivariate analysis, pericardial rub (p = 0.023; odds ratio [OR], 5.45), absence of collaterals (p = 0.011; OR, 0.16), and Killip class > 1 (p = 0.027; OR, 3.80) were the significant variables related to persistent PE. CONCLUSIONS: PE remains a relatively common complication of AMI even in the era of reperfusion therapy and is associated with increased mortality. Furthermore, the presence of a pericardial rub, Killip class > 1, and absence of collateral flow in the early phase of the infarct are associated with persistence of the PE to 1 month after the onset of AMI.

Angioplasty, Balloon, Coronary↗

[The ideal form of laboratory information management].

In a clinical laboratory, not many staff can point out the problems of laboratory information management. Although the clinical laboratory introduced information systems in early stage, no organization supplies specialists to this field. Much knowledge is hidden in the clinical laboratory data, which can be discovered by data-mining technology. We can contribute to medical development with this technology. Moreover, the cost of routine work and research work may also be mitigated. However, data-mining technology including structurally recorded data and diversified analytic systems are required to build such capability. The laboratory information management division should make sufficient use of the formal information with non-fixed data base searching. This section should become an important section in the hospital by supplying advanced knowledge discovery and strategic decision-making. In this paper, we discuss the necessity of the information education in the clinical laboratory field and describe the importance of information management in a clinical laboratory.

Clinical Laboratory Information Systems↗

[In vitro susceptibilites to levofloxacin and various antibacterial agents of 11,475 clinical isolates obtained from 52 centers in 2002].

The susceptibilities of bacteria to fluoroquinolones (FQs), especially levofloxacin, and other antimicrobial agents were investigated using 11,475 clinical isolates collected in Japan during 2002. Methicillin susceptible staphylococci, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, the family of Enterobactericeae, Haemophilus influenzae and Acinetobacter spp. exhibited stable and high susceptibilities to FQs. The rate of FQs-resistant MRSA was 80 approximately 90%, being markedly higher than that of FQs-resistant MSSA. The FQs-resistance rate of MRCNS was also higher than that of MSCNS, however, it was lower than that of MRSA. No FQs-resistant clinical isolates of Salmonella spp. were detected in any of the surveys. Thirteen of Escherichai coli 696 isolates, 8 of Klebsiella pneumoniae 630 isolates and 33 of Proteus mirabilis 373 isolates produced extended-spectrum beta-lactamase (ESBL), furthermore 6 of 13 in E. coli, 1 of 8 in K. pneumoniae and 14 of 31 ESBL-producing isolates, and in P. mirabilis were FQs resistant. Attention should be focused in the future on the emergence of ESBL in relation to FQs resistance. The rate of FQs-resistant P. aeruginosa isolated from urinary tract infection (UTI) was 40 approximately 60%, while 15 approximately 25% of isolates from respiratory tract infection (RTI) were resistant. IMP-1 type metallo beta-lactamase producing organisms were found in 49 of P. aeruginosa 1,095 isolates, 7 of S. marcescens 586 isolates and 4 of Acinetobacter spp. 474 isolates, respectively. Glycopeptide-resistant enterococci or S. aureus was not found.

Anti-Bacterial Agents↗

[Acute myocardial infarction due to late stent thrombosis seventeen months after stent implantation: a case report].

A 59-year-old man with acute myocardial infarction underwent successful stent implantation for proximal left anterior descending coronary artery occlusion. Antiplatelet therapy with 100 mg aspirin/day and 200 mg cilostazol/day was started after stenting and continued for 4 weeks. There was no cardiac event during the 1 year follow-up period. Follow-up coronary angiography at 12 months after stenting revealed no in-stent restenosis. The patient was admitted 17 months later due to sudden onset of severe chest pain. Electrocardiography revealed ST segment elevation in leads V1-V4. Emergency coronary angiography disclosed obstruction of the proximal left anterior descending coronary artery with thrombus. Intracoronary aspiration thrombectomy was successful. We describe a patient with acute myocardial infarction who had late stent thrombosis 17 months after stent implantation.

Coronary Angiography↗

[Ischemic heart disease].

Ischemic heart disease is one of the leading causes of death in Japan. Acute coronary syndrome (ACS) most commonly begins with atherosclerotic plaque rupture and intracoronary thrombus formation. Therefore, the primary goal of treatment of acute coronary occlusion is the achievement of early and complete reperfusion. To achieve this goal, detection of atherosclerosis and/or myocardial necrosis by imaging and serologic tests is important. Original diagnosis of acute myocardial infarction (AMI) was made from typical symptoms, characteristic rises in serum enzyme levels, and an atypical electrocardiographic pattern. Increasingly sensitive and specific tests have been developed in recent years and have been rapidly adopted into clinical practice. Rapid developments in technology in the field of serum biomarkers have redefined the diagnosis of AMI. The new ESC/ACC criteria place increased emphasis on cardiac biomarkers, especially troponins. However, the electrocardiogram still remains significant in the diagnosis of AMI and the ability to identify high risk subgroups by admission electrocardiogram is necessary to estimate the severity of AMI. Current practice guidelines recognize the importance of promptly restoring normal epicardial blood flow, but blood flow to the ischemic tissue may still be impeded after relief of the occlusion; a phenomenon known as no reflow. Myocardial scintigraphy is one of the methods for defining coronary microvascular injury in the acute phase of AMI. Prompt assessment of coronary perfusion and detection of coronary microvascular injury may aid in making decisions concerning the use of drugs to improve microvascular function and left ventricular function after primary coronary angioplasty.

Humans↗

Effect of electrical modification of cardiomyocytes on transcriptional activity through 5'-AMP-activated protein kinase.

Endothelin-1 (ET-1) is known as an aggravating factor of the failing cardiomyocytes and, therefore, a therapeutic method is indispensable to decrease cardiac ET-1 expression. To study the mechanisms of how cardiac ET-1 gene expression can be modified, we investigated the effect of electrical stimulation against cardiomyocytes. Considering the physiology of cardiomyocytes, in vitro cultured cardiomyocytes demonstrate distinctive features from in vivo cardiomyocytes (i.e. the absence of a stretch along with electrical stimulation). In this study, we especially focused on the effect of electrical stimulation. The electrical stimulation reduced the gene expression of ET-1 mRNA in rat primary cultured cardiomyocytes. Furthermore, this effect on the transcriptional modification of ET-1 was also identified in H9c2 cells. Luciferase activity using H9c2 cells was decreased by electrical stimulation in the early phase, suggesting that the attenuation of the ET-1 gene transcription by electrical stimulation should be due to a transcriptional repression. To further investigate a trigger signal involved in the transcriptional repression, phosphorylation of 5'-AMP-activated protein kinase (AMPK) was evaluated. It was revealed that AMPK was phosphorylated in the early phase of electrical stimulation of H9c2 cells as well as in rat primary cultured cardiomyocytes, and that AMPK phosphorylation was followed by ET-1 transcriptional repression, suggesting that electrical stimulation directly regulates AMPK. This study suggests that AMPK activation in cardiomyocytes plays a crucial role in the transcriptional repression of ET-1.

AMP-Activated Protein Kinases↗