Biomedical subjects

T Nada

Publications and source records attributed to T Nada.

At least 19 recordsLinked to original sources

PubMed2003

Transthoracic Doppler echocardiographic measurement of left atrial appendage blood flow velocity: comparison with transoesophageal measurement.

AIM: We validated transthoracic echocardiographic measurements of left atrial appendage flow velocity by comparing them with transoesophageal echocardiographic measurements. METHODS AND RESULTS: Eighty-four consecutive patients (mean age, 64.6 years) with various cardiac diseases, who underwent both transthoracic echocardiography and transoesophageal echocardiography were studied. Thirty-two patients were in sinus rhythm, and the remaining 52 patients were in atrial fibrillation. On transthoracic echocardiography, the transducer was placed somewhat superior and outside from the position viewing the conventional parasternal short-axis image of the aortic valve, so that the angle between left atrial appendage midline and Doppler beam could be narrowed. The left atrial appendage flow velocity pattern was recorded by pulsed Doppler mode with a sampling volume placed at the left atrial appendage orifice on both transthoracic echocardiography and transoesophageal echocardiography. In both approaches, the peak emptying velocity (LAA-E) and the peak filling velocity (LAA-F) of the left atrial appendage were measured. In sinus rhythm, the LAA-E was detectable in 25 of the 32 patients (78.1%) and the LAA-F in 20 of the 32 patients (62.5%). Both LAA-E and LAA-F were detectable in 46 of the 52 patients (88.5%) in atrial fibrillation. Good correlations of LAA-E and LAA-F were observed between transthoracic echocardiography and transoesophageal echocardiography measurements in sinus rhythm (r=0.94, r=0.95, respectively; both, P<0.0001) and in atrial fibrillation (r=0.89, r=0.95, respectively; both, P<0.0001). CONCLUSIONS: The left atrial appendage flow velocities could be sufficiently recorded and assessed by transthoracic echocardiography in 84 Japanese unselected consecutive patients with sinus rhythm or atrial fibrillation.

Adult↗

PubMed2002

Autonomic nervous activity before and after eradication of Helicobacter pylori in patients with chronic duodenal ulcer.

BACKGROUND: Helicobacter pylori infection is involved in the formation of chronic peptic ulcer. However, a previously reported hypothesis concerning the involvement of central autonomic nervous disorder in this condition cannot be ruled out. AIM: To use spectrum analysis of heart rate viability to examine autonomic nervous activity before and after H. pylori eradication. METHODS: Twenty patients with chronic duodenal ulcer (duodenal ulcer group) and 20 age-matched normal adults (N group). In both groups, 24-h Holter electrocardiograms (ECGs) were recorded and spectrum analysis of heartrate variability was performed. In the duodenal ulcer group, Holter ECG was recorded before and after H. pylori eradication. RESULTS: In the N group, analysis of heart rate variability showed that high frequency (HF) power, an index of parasympathetic activity, was high at night, while the low frequency (LF)/HF ratio, an index of sympathetic function, was high during the daytime. In the duodenal ulcer group, HF power was higher at night than during the daytime, showing a similar pattern to the N group, but the power value was higher than in the N group (P < 0.05). In the duodenal ulcer group, LF/HF at night was significantly higher than that of the N group. In addition, in the duodenal ulcer group, autonomic activity after H. pylori eradication did not differ significantly from that before H. pylori eradication. CONCLUSIONS: In patients with chronic peptic ulcer, both sympatheticotonia and parasympatheticotonia may occur at night, and this abnormality in autonomic nervous activity may cause increased gastric acid secretion and gastric mucosal vasoconstriction. Abnormalities in autonomic activity persist even after H. pylori eradication, suggesting that they may be an independent risk factor in the formation of chronic peptic ulcer in addition to H. pylori infection.

Autonomic Nervous System Diseases↗

PubMed2001

Impaired retention of technetium-99m tetrofosmin in hypertrophic cardiomyopathy.

The purpose of this study was to determine whether myocardial imaging using technetium-99m tetrofosmin can noninvasively identify myocardial damage in hypertrophic cardiomyopathy (HC). The study consisted of 10 patients with apical HC, 10 with asymmetric septal HC (ASH) group, 5 with dilated cardiomyopathy (DC)-like group, and 20 healthy subjects. With use of a bull's-eye map of single-photon emission computed tomographic imaging, the total defect score of tetrofosmin and the washout rate were assessed in 5 segments (septum, and anterior, lateral, and inferior walls, and apex) of the left ventricle. A localized increase in defect score and washout rate was observed in the hypertrophied region in the group with apical HC. An increased washout rate was observed in the ASH group regardless of hypertrophy, suggesting that tetrofosmin retention by the mitochondria was impaired in the entire left ventricular wall. The washout rate was further increased at all segments in the DC-like group versus the ASH group. Tetrofosmin retention by mitochondria was impaired in the entire left ventricular wall in the ASH group and was increased further in the DC-like group. The dysfunction of myocardial cells was limited to the hypertrophied region in the apical HC group.

Cardiomyopathy, Dilated↗

PubMed2001

Respiratory function in active firefighters.

BACKGROUND: Exposure to environmental pollution during firefighting may results in the development of respiratory disorders in firefighters. METHODS: The health effects of firefighting on respiratory function was investigated in a group of 128 active firefighters by recording respiratory symptoms and measuring lung function. In addition, 88 control workers, not exposed to known pollutants were studied for the prevalence of acute and chronic respiratory symptoms. RESULTS: Significantly higher prevalences of dyspnea, nasal catarrh, sinusitis, and hoarseness were recorded in firefighters compared to control workers (P < 0.01). One subject developed asthma symptoms following two intense firefighting episodes. A high prevalence of acute symptoms experienced during and after fire extinguishing was also documented among these firefighters. Eye and throat irritation as well as headache were prominent. A logistic regression analysis of chronic respiratory symptoms demonstrated that odds ratios were significant for both duration of work exposure and for smoking. Lung function testing demonstrated a decrease in FEF75 in relation to predicted suggesting obstructive changes in the smaller airways. A regression analysis of ventilatory capacity tests indicated a positive relationship of forced vital capacity with length of employment, 1 s forced expiratory volume as well as FEF50 were related to smoking, and FEF75 was related to both smoking and length of employment. CONCLUSIONS: Our data suggest that firefighters are at risk for developing acute and chronic respiratory symptoms as well as obstructive airway changes.

Adult↗

PubMed2001

[Antimicrobial activities and mechanisms of carbapenem resistance in clinical isolates of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter spp].

We tested the antimicrobial activities of meropenem (MEPM), imipenem (IPM), panipenem (PAPM), piperacillin (PIPC), cefepime (CFPM), aztreonam (AZT), amikacin (AMK), and levofloxacin (LVFX) against 106 clinical Pseudomonas aeruginosa isolates and 64 clinical Acinetobacter spp. isolates with reduced susceptibility to carbapenems. Using NCCLS breakpoints, the percentages of P. aeruginosa strains susceptible to AMK and Acinetobacter spp. strains susceptible to LVFX were found to be 51.1% and 55.6%, respectively, which represented the highest activity among 8 antimicrobial agents in each organism. Referring to the correlations among MICs of carbapenems, MEPM showed a higher activity than IPM and PAPM in both organisms; 29 of the 94 strains (30.9%) of IPM-resistant P. aeruginosa were susceptible to MEPM. Further study for resistance mechanisms to carbapenems by the disk diffusion method using 2-mercaptopropionic acid revealed that 8 of the 64 Acinetobacter spp. isolates (12.5%) were metallo-beta-lactamase producers, while none of 106 P. aeruginosa isolates were metallo-beta-lactamase producers. PCR analysis using blaIMP-specific primers confirmed that 4 of the 8 metallo-beta-lactamase-producing Acinetobacter spp. isolates detected by the disk diffusion method were carrying the blaIMP gene. The identification of metallo-beta-lactamase-producing Acinetobacter spp. isolates implies that metallo-beta-lactamase genes have been disseminated among various gram-negative pathogens.

Acinetobacter↗

PubMed2001

Apoptotic signaling pathway activated by Helicobacter pylori infection and increase of apoptosis-inducing activity under serum-starved conditions.

The enhanced gastric epithelial cell apoptosis observed during infection with Helicobacter pylori has been suggested to be of significance in the etiology of gastritis, peptic ulcers, and neoplasia. To investigate the cell death signaling induced by H. pylori infection, human gastric epithelial cells were incubated with H. pylori for up to 72 h. H. pylori infection induced the activation of caspase -8, -9, and -3 and the expression of the proapoptotic Bcl-2 family proteins Bad and Bid. The peak of the activity of the caspases occurred at 24 h. At this time, the inhibition of caspase-8 or -9 almost completely suppressed H. pylori-induced apoptosis. Inhibition of caspase-8 suppressed the expression of Bad and Bid and the subsequent activation of caspase-9 and -3. These observations indicate that H. pylori induces apoptosis through a pathway involving the sequential induction of apical caspase-8 activity, the proapoptotic proteins Bad and Bid, caspase-9 activity, and effector caspase-3 activity. Activation of the pathway was independent of CagA or vacuolating toxin. A membrane fraction of H. pylori was sufficient to activate this pathway, and treatment with proteinase K eliminated the activity. Apoptotic activity of the membrane fraction was significantly increased by incubating the bacteria under serum-starved conditions for 24 h. These observations suggest that environmental conditions in the human stomach could induce H. pylori-mediated pathogenesis, leading to a variety of clinical outcomes.

Apoptosis↗

PubMed2001

Autonomic nervous function in patients with peptic ulcer studied by spectral analysis of heart rate variability.

This study is intended to clarify the relationship between occurrence of peptic ulcer disease and dysfunction of the autonomic nervous system. We studied heart rate variability and assessed the circadian rhythm of autonomic nervous function in 20 patients with peptic ulcer (PU group) and 20 age-matched healthy controls (N group) using 24-hour Holter monitoring. Moreover, the relationship between gastric juice secretion and autonomic activity was examined under intravenous injection of insulin or butylscopolamine in adult mongrel dogs. High frequency spectral (HF) power, an indicator of parasympathetic tone, was increased markedly at night in the PU group. Low frequency spectral (LF) power, an indicator of sympathetic tone modified by vagal tone, was higher during the day than at night in the N group, whereas this normal circadian rhythm of LF power disappeared in 11 cases (55%) in the PU group. In addition, the LF power was increased significantly at night (p<0.01) in the PU group. HF power and gastric juice secretion was increased by the administration of insulin. High sympatho-vagal tone at night may result in spasm of gastric arteries and excess secretion of gastric acid in the PU group. These results suggest that the nocturnal acceleration of LF, HF, and LF/HF is related to peptic ulcer diseases.

Adult↗

PubMed2000

Stress and coping behavior in patients with diabetes mellitus.

Diabetes mellitus is a disease which must be controlled over the lifetime of a patient. We investigated the issues of stress and coping for diabetes mellitus which may influence self-management. In addition, we examined the association of these factors with blood glucose control, in order to review self-management instructions for diabetes mellitus. The study included 153 patients with diabetes mellitus. The patients were divided into two subgroups: good-control group, comprising patients with glycohemoglobin (HbA1c) values less than 7.0%; and poor-control group, comprising those with HbA1c values of 7.0% or more. All patients responded to a questionnaire regarding stress tolerance, Jalowiec and Power's coping scale and awareness of diabetes mellitus. Stress tolerance was not significantly different between the good-control and poor-control groups. No significant gender differences in coping score were evident for the good-control group. However, in the poor-control group, the coping score in men was significant higher than that in women. The problem-oriented coping score for men in the poor-control group was significantly higher than that for the good-control group (p < 0.01). In a comparison of awareness of diabetes mellitus, the proportion of patients who replied that they were rigidly following diabetes treatment was higher in the poor-control group than the good-control group. Patients with diabetes mellitus may have a knowledge of the disease and a strong will to resolve problems. This is especially true for male patients in that their will appeared to be stronger, but they may not have the resolve to establish appropriate behavior patterns. In the future, methods for evaluating self-management should be included in diabetes education.

Adaptation, Psychological↗

PubMed2000

Age-related changes in the magnitude of ventricular depolarization vector: analyses by magnetocardiogram.

The magnetocardiogram has the beneficial feature that permits the strength and location of the current dipole to be estimated. This study examines the issue of whether the magnitude of the heart current during depolarization phase was influenced by the age of healthy subjects. The magnetocardiograms were recorded by means of a second-derivative SQUID (superconducting quantum interference device) magnetometer (BT Corp, Model BMP, San Diego, CA) in 150 healthy subjects. The subjects were subgrouped into 5 age-based categories according to the age. The current dipole of the maximum QRS complex was determined from isofield contour maps during the ventricular depolarization phase, and no significant differences were observed in the magnitude in the current source for any age category. However, the amplitudes of the RV5 and SV1 + RV5 in the standard electrocardiogram were larger in 65 to 74-year-old women than other age groups, and the SV1 + RV5 was smaller for the 45 to 74-year-old men than for the men aged 25 to 44 years. These findings suggest that the age-associated changes in the QRS complex observed by the electrocardiogram are caused by increased electric resistance and not by the heart current itself. The results additionally suggest that no effects of aging were observed in the actual heart current of the heart during the depolarization phase.

Action Potentials↗

PubMed2000

Is autonomic dysfunction a necessary condition for chronic peptic ulcer formation?

BACKGROUND: The relationship between 1/f fluctuation of the heart rate variability and Helicobacter pylori infection was evaluated, in order to clarify whether autonomic nervous dysfunction is a necessary condition for chronic peptic ulcer formation. METHODS: The subjects were 11 patients with recurrent chronic peptic ulcer and 20 age-matched normal subjects. Holter ECGs were recorded over 24 h, and the 1/f(-x) fluctuation of the heart rate was computed. The 1/f(-x) fluctuation of the heart rate is a novel index of autonomic function that has been shown to reflect a patient's pleasant mood. For 1/f(-x) fluctuation, the slope of the regression line (-x) was determined and cosine fitting of the absolute slope of the regression line over a 24-h period was performed. RESULTS: For the normal group, the absolute slope of the regression line during daytime and night-time were 0.53 +/- 0.16 and 1.05 +/- 0.18, respectively. For the peptic ulcer group, the corresponding values during daytime and night-time were 0.94 +/- 0.15 and 1.84 +/- 0.18, respectively. The mean value of the cosine curve was 0.76 +/- 0.23 in the normal group and 1.12 +/- 0.25 in the peptic ulcer group. Thus, these values were significantly higher for the latter group than for the former group (P<0.05). No statistically significant difference in H. pylori infection between the two groups was observed. CONCLUSIONS: Autonomic nervous dysfunction as well as H. pylori infection appears to be a necessary condition for chronic peptic ulcer formation.

Aged↗

PubMed2000

Evaluation of autonomic nervous function in patients with essential hypertension complicated with peptic ulcer.

BACKGROUND AND AIMS: The relationship between peptic ulcer, autonomic activity and the incidence of Helicobacter pylori infection in untreated hypertensive patients complicated with peptic ulcer were evaluated. METHODS: Ten hypertensive patients with peptic ulcer (HT-PU group), 15 untreated essential hypertensive patients without peptic ulcer (HT group) and 10 normal subjects (N group) were enrolled, and a power spectral analysis was performed in each subject. A biopsy urease test was used to detect infection by H. pylori. RESULTS: No significant differences were observed in the values of mean low-frequency (LF) power between the three groups. However, the mean high-frequency (HF) power in the HT-PU group was significantly greater than those of the HT and N groups (P<0.01). The mean LF/HF ratios in the HT-PU and HT groups were significantly greater than that of the N group (P<0.01). With respect to H. pylori infection, no significant differences between the three groups were observed. Sympathetic activity (LF power) was increased in the HT and HT-PU groups. Furthermore, parasympathetic activity (HF power) was increased in the HT-PU group. CONCLUSIONS: These findings suggest the participation of increased parasympathetic activity in peptic ulcer patients. Therefore, it is suggested that new techniques, such as spectral analysis of heart rate variability, as used in this study, will clarify the relationship between peptic ulcer and autonomic nervous function.

Autonomic Nervous System↗

PubMed1999

Evaluation of cardiac function in myocardial infarction patients by ECG 99mTc-MIBI gated SPECT using a three-dimensional perfusion/motion map procedure.

Three-dimensional (3D) radionuclear myocardial imaging has improved the evaluation of left ventricular wall motion. However, there have been no studies evaluating left ventricular function using 3D-perfusion/motion map techniques. We hypothesized that the 3D-perfusion/motion map could accurately evaluate left ventricular wall motion even in patients with a history of myocardial infarction. Electrocardiogram (ECG)-gated single photon emission computed tomography (SPECT) using 99mTc-methoxy isobutyl isonitrile (MIBI) was performed in 20 patients with a history of myocardial infarction who underwent left ventriculography. Myocardial imaging data were collected during ECG-gated SPECT using a 3-headed gamma camera. Reconstructed 3D SPECT images were oriented to correspond to standard left ventriculography views (right anterior oblique and left anterior oblique projections), and the shortening fraction (SF) was calculated using the center line method. The SF and left ventricular ejection fraction from 3D SPECT images were compared with those determined by left ventriculography. There was a significant correlation between left ventriculography and the 3D-perfusion/motion map procedure in determining SF for all regions of the left ventricle except the anterobasal and posterior segments by using the Bland and Altman method. The 3D-perfusion/motion map procedure offers the advantage that the influences of contraction-related myocardial torsion and three-dimensional compression are minimized. In addition, this method facilitates evaluation of images from nonstandard projections. We conclude that this method may be useful for evaluating left ventricular function.

Aged↗

PubMed1999

Ultrasonographic arterial portography with second harmonic imaging: evaluation of hepatic parenchymal enhancement with portal venous flow.

Ultrasonographic arterial portography was evaluated with second harmonic and conventional gray scale imaging after the administration of 0.001 to 0.1 ml/kg of FS069 (Optison) in 10 dogs (four dogs with ligation of the portal vein branch) and two woodchucks with hepatocellular carcinomas. Harmonic imaging was required to obtain good liver parenchymal enhancement for ultrasonographic arterial portography to be useful. The tumors were visible as regions of greater enhancement after intravenous injection and as hypoechoic regions after superior mesenteric artery injection. The segments with portal vein ligation were not detected after intravenous injection but were clearly seen after superior mesenteric artery injection. Doppler signal measurement verified a significant difference between the portal vein and hepatic vein after superior mesenteric artery injection and in the femoral artery after intravenous versus superior mesenteric artery injection, demonstrating that minimal levels of FS069 pass through the liver.

Albumins↗

PubMed1999

[Evaluation of COBAS CORE anti-HIV-1/HIV-2 EIA DAGS for the detection of antibodies to HIV by COBAS CORE].

COBAS CORE Anti-HIV-1/HIV-2 EIA DAGS (CORE HIV-1/2) for the detection of antibodies to HIV-1 and HIV-2 was evaluated by a fully automated immunoassay system, COBAS CORE II (Roche Diagnostics K.K.). The sensitivity of CORE HIV-1/2 was assessed in comparison with PA1/2, Enzygnost, VIDAS and AxSYM by testing serial two-fold dilutions of HIV-1 and HIV-2 sera. CORE HIV-1/2 showed the highest sensitivity than other methods. The agreements of the results of anti-HIV antibodies determinations between the CORE HIV-1/2 and other methods, PA1/2, Enzygnost, VIDAS, and AxSYM, were 99.4%, 100%, 100%, and 99.7%, respectively in the tests for anti-HIV-1 antibody. In the tests for anti-HIV-2, all results were agreed at 100%. Discrepant samples which showed a negative by CORE HIV-1/2 and a positive by PA1/2 and AxSYM were clearly negative of anti-HIV-1 antibody by p24 ACA, PCR, Western blot, and continuous clinical studies. This assay showed excellent coefficients of variation for both within-run and day to day precision. The determination of anti-HIV antibodies was not interfered with hemoglobin, bilirubin, and chylemia. We conclude that the excellent specificity and sensitivity of the CORE HIV-1/2 make the CORE HIV-1/2 a suitable method for diagnosis of HIV-1 and HIV-2 infections in clinical laboratories.

Evaluation Studies as Topic↗

PubMed1998

Mucosal macrophage inflammatory protein-1alpha levels are increased in Helicobacter pylori infection.

We examined the relationship between the levels of macrophage inflammatory protein 1alpha (MIP-1alpha) and interleukin-8 (IL-8) in organ cultures of antral mucosal tissues, background gastroduodenal diseases, and grades of histologic gastritis. Significantly higher levels of MIP-1alpha and IL-8 were detected in patients with H. pylori infection than in those without infection. In H. pylori-positive patients, mucosal specimens from patients with peptic ulcer disease showed higher levels of MIP-1alpha and IL-8 than the specimens obtained from patients with erosive gastritis or those from endoscopically normal mucosa, and this was particularly pronounced in patients with duodenal ulcer. There were positive correlations between MIP-1alpha and IL-8 levels and histologic grades of activity, inflammation, and H. pylori density as defined by the Sydney system. However, the degree of association with the inflammatory cell count was different between these two chemokines. MIP-1alpha levels had a stronger association with mononuclear cells than with neutrophils, whereas IL-8 levels showed an association with neutrophils and mononuclear cells to an almost equal degree. These results suggest that MIP-1alpha and IL-8 may play important roles as inflammatory mediators in the pathogenesis of histologically proven H. pylori-associated gastritis.

Adult↗

PubMed1998

Differential normalization of mucosal interleukin-8 and interleukin-6 activity after Helicobacter pylori eradication.

There is differential resolution of mucosal infiltration with neutrophils and mononuclear cells following successful Helicobacter pylori eradication. We investigated the effects of H. pylori eradication on mucosal interleukin-8 (IL-8) and IL-6 activity in relation to the resolution of H. pylori-associated gastritis. Eighty-one duodenal ulcer patients with H. pylori infection received dual- or triple-treatment eradication therapy, and mucosal biopsy specimens obtained at the initial and follow-up endoscopic examinations were cultured in vitro for 24 h. The levels of IL-8 and IL-6 were measured by enzyme-linked immunosorbent assays. In the 42 patients in whom H. pylori eradication failed, there was little change in the numbers of neutrophils and mononuclear cells infiltrating the mucosa and in IL-8 and IL-6 activity. In the 39 patients in whom H. pylori was eradicated, there was normalization both in the numbers of infiltrating neutrophils and in mucosal IL-8 activity, which was evident within 1 month following therapy. In contrast, there was a gradual resolution of mononuclear cell infiltration over a 6-month period, accompanied by a gradual normalization in IL-6 levels. Addition of H. pylori to cultures of mucosal tissues induced a significant increase in IL-8 activity in both uninfected control subjects and patients from whom H. pylori was eradicated. However, this introduction yielded a significant increase in IL-6 activity only in the latter group. This study indicates a dichotomy in the changes of mucosal IL-8 and IL-6 activity after H. pylori eradication. The rapid normalization of IL-8 after H. pylori eradication and the ability of H. pylori cells to stimulate IL-8 in control tissues indicate that IL-8 induction is a part of the innate (nonimmune) responses to this organism. In contrast, the results of experiments analyzing IL-6 activity in cultured mucosal tissues suggest that the gradual resolution of mucosal IL-6 activity and mononuclear infiltration after successful eradication observed in vivo may reflect gradually diminishing residual immune responses against H. pylori.

Adult↗

PubMed1998

Evaluation of a membrane filter assay system, Ortho HCV Ab Quick Pack, for detection of anti-hepatitis C virus antibody.

A simple membrane immunoassay assay system, Quik Pack, for the detection of hepatitis C virus antibody was compared with two enzyme-linked immunosorbent assays (ELISAs) in a study of 600 serum samples. Quik Pack exhibited excellent sensitivity and specificity: 96.0 and 99.7%, respectively, versus the ELISA-2 and 99.7 and 99.4%, respectively, versus the ELISA-3.

Enzyme-Linked Immunosorbent Assay↗

PubMed1998

Brugada syndrome associated with an autonomic disorder.

A 44 year old man with Brugada syndrome and ventricular fibrillation had an autonomic disorder, shown by spectral analysis of heart rate variability and 123I-MIBG myocardial scintigraphy. Periodic variation of the ST segments was detected by Holter ECG. Increased high frequency power (0.15-0.40 Hz), an index of parasympathetic nerve activity, was observed just before ST segment elevation. In addition, local dysfunction of sympathetic nerves in the left ventricle was detected by 123I-MIBG myocardial scintigraphy. Unbalanced autonomic nerve function plays an important role in inducing Brugada-type ECG signs.

Adult↗