Biomedical subjects

K Katayama

Publications and source records attributed to K Katayama.

At least 199 records · Page 11Linked to original sources

PubMed1996

Long-term biochemical and virological response to natural interferon-alpha in patients with chronic hepatitis C.

To determine the long-term response to interferon-alpha, 134 patients with chronic hepatitis C were followed for more than a year after therapy. Follow-up was stopped for 14 patients and 43 patients received retreatment. The remaining 77 patients were followed for 26-46 months, and 39 of them achieved long-term sustained alanine aminotransferase (ALT) normality. This normality was achieved in 35/38 short-term sustained responders, which was significantly higher (P < 0.001) than in the short-term relapsers (2/38) and the short-term nonresponders (2/44). Hepatitis C virus (HCV) RNA remained negative in 27 (73%) of 37 patients in the long-term sustained ALT normality group. However, only one (1.6%) of 63 long-term responders was negative for HCV RNA. The results of HCV RNA testing for the long-term period agreed with those at three to six months after therapy. Serum ALT levels during the first six months after therapy and HCV RNA testing at three to six months after therapy are important for predicting long-term sustained ALT normality and HCV RNA negativity.

Adult↗

PubMed1996

Prolongation of QTc interval and autonomic nervous dysfunction in diabetic patients.

We have attempted to clarify the relationships of the QTc interval to alpha and beta sympathetic, as well as parasympathetic function tests including spectral analyses of the R-R interval and systolic blood pressure. The QTc intervals were estimated in 76 diabetic patients and 76 age-matched healthy controls whose R-R intervals were comparable to those of the diabetic patients. We also investigated the relationships of the QTc interval to various clinical features of diabetes mellitus and to autonomic function tests. The QTc interval in diabetic patients was significantly greater than that in healthy controls. The QTc intervals were unrelated to diabetic control, retinopathy and nephropathy, but were prolonged in patients with a long duration of diabetes as compared to those with a short disease duration. There were significant correlations between the QTc interval and orthostatic hypotension, R-R variation and the Valsalva maneuver. Significant correlations were observed between the QTc interval and both the low and the high frequency component of spectral analysis of the R-R interval, whereas no correlations were found with spectral analysis of systolic blood pressure. An abnormal QTc interval is an indicator of cardiac sympathetic and parasympathetic nervous dysfunction, but not vasomotor dysfunction.

Blood Glucose↗

PubMed1996

Effects of intraoperative chemohyperthermia in patients with gastric cancer with peritoneal dissemination.

BACKGROUND: The most common cause of noncurative resection and recurrence is gastric cancer is peritoneal seeding. However, the results of treatment of peritoneal dissemination with chemotherapy have been poor with 5-year survival rates of 0%. METHODS: A new in vitro thermochemosensitivity test was performed on gastric cancer cells obtained from 19 surgically resected specimens by using tetrazolium-based colorimetric assay (MTT assay). A novel treatment of the intraoperative chemohyperthermia was undertaken in 83 patients with gastric cancer with peritoneal dissemination. After aggressive resection of primary tumor, lymph nodes, and peritoneal metastases, warmed saline solution containing mitomycin C 30 mg, etoposide 150 mg, and cisplatin 300 mg was introduced into the peritoneal cavity via a closed circuit continuous hyperthermic peritoneal perfusion (CHPP) for 60 minutes to keep the abdominal temperature at 42 degree to 43 degrees C by means of a heat exchange mechanism. RESULTS: The in vitro thermochemosensitivity test that 43 degrees C enhanced the cytotoxin effects on gastric cancer cells under clinically achievable drug concentrations. During CHPP, drug concentrations of cisplatin, mitomycin C, and etoposide in the perfusate remained statistically higher than in the peripheral venous circulation. Among 43 evaluable patients with residual peritoneal seeding, eight (19%) and nine (21%) exhibited complete response and partial response, respectively. The overall 1- and 5-year survival rates were 43% and 11%, respectively. Patients who underwent complete resection survived significantly longer than those with residual disease, and those with complete response had a significantly better prognosis than did those with partial response, and nonresponders. One-year survival rates with complete response, partial response or nonresponders were 88%, 27% and 22%, respectively. Five patients survived longer than 5 years. CONCLUSIONS: Our triple treatment combining surgery and CHPP is an effective therapy for selected patients with gastric cancer with peritoneal dissemination.

Adult↗

PubMed1996

Fas antigen expression in liver tissues of patients with chronic hepatitis B.

BACKGROUND: Hepatitis B virus-infected cells can be eliminated by the cytotoxic T cell-mediated immune reaction. Fas ligand, recently detected on the surface of cytotoxic T cell, is thought to induce cells to apoptosis by adhering to Fas antigen. AIMS/METHODS: To evaluate the role of Fas antigen and apoptosis in chronic hepatitis B, we immunohistochemically studied Fas antigen and HBsAg expression in liver samples from patients with hepatitis B virus infection. RESULTS: In samples from 56 HBV patients, Fas antigen was mainly expressed in the cytoplasm (partly at the membrane) of hepatocytes, and these positive cells were detected especially at the periportal region near "piecemeal necrosis". According to Knodell's HAI scoring system, the scores of periportal inflammation and necrosis (category I) and the scores of intralobular inflammation and necrosis (category II) were similarly higher in Fas antigen-positive cases than in Fas antigen-negative cases (p < 0.01), and there was a positive correlation between these scores and the degree of Fas antigen expression. In normal cases, Fas antigen was not detected. In patients with HBV infection, Fas antigen expression was closely correlated with the activity of the viral hepatitis. HBsAg was expressed by the majority of hepatocytes. However, Fas antigen was expressed by fewer hepatocytes than the number of HBsAg-positive cells. CONCLUSIONS: These findings suggest that the expression of Fas antigen may not be triggered only by HBV infection, and immunological interaction may be needed for the expression and for apoptosis to occur.

Adolescent↗

PubMed1996

Kinetics of swelling of compressed cellulose matrices: a mathematical model.

PURPOSE: A model for swelling time course of compressed cellulose matrix is presented. METHODS: The model incorporates the two most important features: water penetration by diffusion and volume change due to swelling. Approximations of the model for small t values and for large t values are also derived, which are utilized in a handy routine for estimation of swelling parameters. RESULTS: The observed time courses of thickness change with compressed matrices of methyl cellulose and hydroxypropyl cellulose agree well with the calculated values of the proposed model. CONCLUSIONS: The proposed model is compatible with the observed swelling kinetics.

Cellulose↗

PubMed1996

Quantitative analysis of antibody to hepatitis C virus envelope 2 glycoprotein in patients with chronic hepatitis C virus infection.

The significance of circulating antibody to hepatitis C virus (HCV) envelope glycoprotein 2 (E2)/nonstructural protein 1 (NS1) glycoprotein was studied in 83 patients with chronic HCV infection diagnosed by polymerase chain reaction (PCR). E2/NS1 antibody was quantitatively examined by a passive hemagglutination test using recombinant E2/NS1 glycoprotein encompassing amino acids 388 to 664 of the HCV-H strain. The results were correlated with clinical and virological features such as genotypes and viremic levels assessed by a competitive reverse-transcription PCR assay. E2/NS1 antibody was found in 73 patients (88%), and its occurrence was related to viremic levels. E2/NS1 antibody titers were low in asymptomatic HCV carriers with low levels of viral replication; 9 of 17 such patients tested positive for E2/NS1 antibody (53%), compared with 64 of 66 chronic hepatitis C patients (97%) (P < .01). A significant direct relationship was observed between viremic levels and E2/NS1 antibody titers (r = .52, P < .01). Of the 13 patients with low viremic levels of < 10(6) copies/mL, only 5 tested positive for E2/NS1 antibody (38%), whereas 68 of the 70 patients with viremic levels of > or = 10(6) copies/mL had it (97%) (P < .01). As for the relation to HCV genotypes, no difference was seen in E2/NS1 antibody titers among genotypes examined (1b, 2a, and 2b). These findings suggest that the E2/NS1 antibody tested exhibits no neutralizing activity in chronic HCV infection but may serve as a serological indicator of active virus replication.

Adult↗

PubMed1996

The existence of thyroid hormone responsive element, TRE, was confirmed in the first intron of rat alpha 1-acid glycoprotein gene.

A set of acute-phase proteins was found to have been induced in rat after triiodothyronine (T3) treatment. To study the mechanism of gene activation by T3, the rat gene of alpha 1-acid glycoprotein (AGP), one of the major acute-phase proteins, was cloned and analyzed. CAT assay identified a thyroid hormone responsive element (TRE) in the first intron of the AGP gene and showed that mutations introduced into the TRE region destroyed the TRE activity. Gel shift assay and methylation interference assay showed that the thyroid hormone receptor bound to the TRE. The TRE identified here had a palindromic structure and was highly homologous to other known TREs.

Acute-Phase Proteins↗

PubMed1996

Comparative effects of type 1 angiotensin II-receptor blockade with angiotensin-converting-enzyme inhibitor on left ventricular distensibility and collagen metabolism in spontaneously hypertensive rats.

We compared the cardiac effects of the selective angiotensin II type 1 (AT1)-receptor blockade, FK-739, with an angiotensin-converting-enzyme (ACE) inhibitor, enalapril, on left ventricular (LV) distensibility and collagen metabolism in spontaneously hypertensive rats (SHRs). We treated 14-week-old SHRs with FK-739 (30 mg/kg/day) or enalapril (10 mg/kg/day) for 6 weeks. Both FK-739 and enalapril induced a significant decrease in blood pressure (p < 0.001) and regression of LV hypertrophy (p < 0.001) compared with vehicle, with no differences between the treated groups. Furthermore, FK-739 caused a greater decrease in LV collagen content than did enalapril (FK-739-treated group, 3.06 +/- 0.11 mg/g; enalapril-treated group, 3.47 +/- 0.05 mg/g; p = 0.015) with no change in collagen phenotypes. Hearts taken from rats treated with FK-739 also showed greater LV distensibility than those taken from enalapril-treated rats (FK-739-treated group vs. enalapril-treated group at > or = 15 mm Hg, p < 0.001). These results suggest that, compared with ACE inhibition, AT1-receptor blockade may have additional effects on LV distensibility and collagen metabolism in the regression of LV hypertrophy induced by pressure overload.

Angiotensin Receptor Antagonists↗

PubMed1996

Influence of pH on skin permeation of amino acids.

Skin permeation of amino acids through excised rat skin was measured at various pH values. The permeabilities varied with the donor pH and amino acid, indicating that each ionic species of amino acid may have a different permeability. The permeability coefficient of each ion was estimated from the permeability-pH profiles using the dissociation constants. The estimated values for mono-cation and uncharged zwitterion were not dependent on the lipophilicity but on the size of the amino acid, suggesting a porous mechanism of transport. The permeability coefficient was highest for di-cation, followed by mono-cation, positively charged, uncharged and negatively charged zwitterions. The electrical potential difference across the skin was too small to affect the permeation of ions. The permselective property of skin thus seems to be determined by the difference of diffusivity in aqueous pores of skin due to the hydration of ions and other factors.

Amino Acids↗

PubMed1996

Effect of dobutamine of ventriculoarterial coupling in acute regional myocardial ischemia in dogs.

We assessed the effect of dobutamine on left ventricoarterial coupling during acute regional ischemia. Using a conductance catheter, we analyzed the end-systolic pressure-volume relation (ESPVR) in anesthetized dogs. We calculated the slope of ESPVR (Ees), the slope of the end-systolic pressure-stroke volume relation (Ea), (Ea/Ees) and the ratio (work efficiency) of external work to pressure-volume area at base-line during ischemia induced by occlusion of the left anterior descending coronary artery and during low-dose (1-3 micrograms.min-1.kg-1) and high-dose (4-10 micrograms.min-1.kg-1)dobutamine infusions with ischemia. ESPVR shifted to the right without a change in Ees during ischemia. Dobutamine caused dose-dependent increases in Ees but did not affect the intercept of ESPVR. During ischemia, Ea/Ees increased and work efficiency decreased. Low-dose dobutamine was associated with a return in control for Ea/Ees and work efficiency. High-dose dobutamine increased Ees and Ea but produced no further increase in Ea/Ees or work efficiency. Low-dose dobutamine would appear to be the preferable regimen to achieve the optimal ventriculoarterial coupling in acute regional ischemia associated with mismatched ventriculoarterial coupling and depressed left ventricular work efficiency.

Acute Disease↗

PubMed1996

Acrania: report of the first surviving case.

The first known surviving case of acrania is presented. The patient was the first child of a 29-year-old Japanese woman. Fetal ventriculomegaly was documented in the 35th gestational week. Prenatal sonography and magnetic resonance imaging suggested hydrocephalus with a wide encephalomeningocele. The baby was born at 38 weeks of gestational age by vaginal delivery. The patient had no calvarium, but did have a complete skull base with a partial defect in the occipital scalp and an underlying dural defect. Subsequently, the patient underwent repair of the scalp defect. At 3 months of age, after hydrocephalus developed, a subduro-peritoneal shunt was placed because of cosmetic and nursing problems. His developmental quotient was 10 at 3 years.

Adult↗

PubMed1996

Assessment of pulmonary venous and transmitral flow in closed-chest dogs under various loading conditions by transesophageal Doppler echocardiography.

Pulmonary venous flow velocity (PVFVe), pulmonary venous dimension (PVD) and transmitral flow (TMF) velocity were examined under various loading conditions in 15 anesthetized closed-chest dogs by transesophageal Doppler echocardiography (TEE). We also compared PVFVe with pulmonary venous flow volume (PVFVo) simultaneously in open-chest dogs using an ultrasonic flow probe. PVFVo decreased by more than 50% and PVD also decreased significantly during preload reduction, while there was no change in PVFVe. This discrepancy between PVFVo and PVFVe was apparently due to the collapse of pulmonary veins. TMF consisted of both rapid-filling flow velocity and atrial flow velocity components (R and A), while PVF consisted of systolic and diastolic forward flow velocity components (S and D). The peak values of R,A,S and D and the time-velocity integrals of each wave (RI, AI, SI and DI, respectively) were measured. There was a significant correlation between the changes in RI and SI/DI during preload reduction (r = 0.82, p < 0.001) and during after-load increase (r = -0.59, p < 0.05). These results suggest that changes in RI with different loading conditions might be attributable to changes in atrial reservoir volume and conduit volume.

Animals↗

PubMed1996

Stroke volume generation of the left ventricle and its relation to chamber shape in normal subjects and patients with mitral or aortic regurgitation.

The total stroke volume of the left ventricle (LV) is equal to the sum of the regional cavity shrinkage. Since nonuniformity of regional wall motion in LV has been well documented even in normal subjects, the extent of the contribution of each region to total stroke volume cannot be easily determined. To assess the left ventricular regional contributions to total stroke volume under normal conditions and in compensated chronic mitral or aortic regurgitation, LV cineangiograms were analyzed in 14 normal subjects (N), 8 patients with mitral regurgitation (MR) and 10 patients with aortic regurgitation (AR). We assumed that the LV cavity could be viewed as a stack of 30 half-cylindrical discs, 15 in the anterior and 15 in the inferior wall regions. LV chamber shape was more spherical in MR than in N, but was more conical in AR. Percent regional hemichordal shortening was significantly decreased in the anterobasal and anteroapical walls in AR, but was similar between N and MR. The regional contribution to total stroke volume showed a significant quadratic correlation with the end-diastolic regional shape index (N, r = 0.87; MR, r = 0.79; AR, r = 0.90), which was defined as the regional hemiaxial length divided by the LV long-axis length, but was not correlated with percent regional hemichordal shortening. Therefore, stroke volume is generated mainly in the mid-ventricular portion in N and MR, but in the basal portion in AR due to the characteristic change in cavity shape.

Adult↗

PubMed1996

The effect of nifedipine on ventriculoarterial coupling in old myocardial infarction.

The effect of nifedipine on ventriculoarterial coupling was examined in 8 patients with old myocardial infarction who showed a depressed ejection fraction (37 +/- 7%). Left ventricular (LV) pressure and LV volume were determined simultaneously by micromanometer and conductance catheter, respectively. We measured the slope (Ees) of the end-systolic pressure-volume relation during transient inferior vena caval occlusion, the slope (Ea) of the end-systolic pressure-stroke volume relation, the ratio of Ea to Ees (Ea/Ees), and the work efficiency (the ratio of external work to the systolic pressure-volume area) at baseline and after the sublingual administration of nifedipine (10 mg). Nifedipine slightly increased the heart rate from 71 +/- 14 to 78 +/- 17 beats/min. Although nifedipine had little effect on Ees (2.54 +/- 0.68 vs 2.47 +/- 0.62 mmHg/ml/m2, ns), it significantly decreased Ea from 3.47 +/- 1.16 to 2.37 +/- 0.54 mmHg/ml/m2. Consequently, Ea/Ees decreased from 1.42 +/- 0.47 to 0.97 +/- 0.31 and work efficiency increased from 48 +/- 12 to 59 +/- 13% after nifedipine administration. These data suggest that nifedipine reduces afterload (Ea) and improves left ventriculoarterial coupling without depressing left ventricular contractility in patients with failing hearts due to old myocardial infarction.

Aged↗

PubMed1996

Effect of right ventricular volume overload on left ventricular diastolic function in patients with atrial septal defect.

This study was undertaken to investigate the effect of chronic right ventricular (RV) volume overload on left ventricular (LV) diastolic function. Twelve patients with atrial septal defect and 7 age-matched normal controls were examined. Patients with atrial septal defect were divided into 2 groups based on their Qp/Qs values (ASD1:Qp/Qs < or = 3, n = 7; ASD2:Qp/Qs > 3, n = 5). The LV volume curve and its first derivative were derived by a frame-by-frame analysis of the left ventriculogram. The peak filling rate was defined by the peak positive first derivative of the LV volume curve. We measured the time constant, isovolumetric relaxation time, stiffness constant and compliance at LV end-diastole. The time constant was significantly prolonged in the ASD2 group compared with the controls, and the isovolumetric relaxation time in both atrial septal defect groups was also prolonged compared with the controls. The peak filling rate, which was normalized by end-diastolic volume, was lower in the ASD2 group than in the controls. Although the stiffness constant and the compliance at LV end-diastole in the controls were not significantly different from those in the atrial septal defect group, an upward and leftward displacement of the left ventricular pressure-volume curve was observed in patients with atrial septal defect. Moreover, a significant correlation (r = 0.78, p < 0.01) was observed between the time constant and RV end-diastolic pressure. Thus, these results suggest that chronic RV volume overload affects left ventricular diastolic function.

Adult↗

PubMed1996

Very low incidence rates of community-acquired hepatitis C virus infection in company employees, long-term inpatients, and blood donors in Japan.

To assess the contemporary rate of hepatitis C virus (HCV) propagation in Japanese community, we conducted a sentinel study on three groups of people: company employees, long-term inpatients, and blood donors. A total of 3079 company employees negative for anti-HCV were followed thereafter, and seroconversion to anti-HCV was found in 5 per 5786 person-years. None of them was positive for HCV RNA. In the group of 703 long-term inpatients (25 of whom were initially positive for anti-HCV) none showed seroconversion to anti-HCV per 2712 person-years. As for 114,266 repeated blood donors who were initially antibody-negative, 227 became anti-HCV positive later. Of these seroconverted donors, 83 were found to have anti-HCV with titers of 2(6) or greater. HCV RNA was positive in only 3 of them. Thus, the incidence rates of acquired HCV viremia in these three groups were 0 for both company employees and long-term inpatients, and 1.78 (95% C.I.: 0.37-5.19) per 100,000 person-years in blood donors. These results suggest that community-acquired HCV infection is now rare in Japan, and that even if it occurred it hardly leads to persistent viremia.

Adolescent↗

PubMed1996

Neurophysiological evidence for altered higher brain functions in NIDDM.

OBJECTIVE: To investigate neurophysiological alterations of higher brain function in patients with NIDDM. RESEARCH DESIGN AND METHODS: Auditory P300 event-related potentials were recorded in 60 NIDDM patients who had no evidence of stroke, dementia, or any other neurological illnesses. The P300 wave latencies in diabetic patients were compared with those in neurologically healthy control subjects, with consideration of clinical parameters and diabetic complications. RESULTS: Diabetic patients had significantly longer P300 latencies than control subjects. Seven diabetic patients had pathologically prolonged P300 values. There was a trend toward longer P300 latencies in diabetic patients with retinopathy and in those with HbA1 of > or = 10%; the differences between these diabetic subgroups and control subjects were both statistically significant. However, three of seven diabetic patients with abnormal P300 latencies had no retinal lesions, and no significant correlation was observed among diabetic patients between P300 latencies and HbA1 levels. Peripheral neuropathy, nephropathy, blood glucose levels, and disease duration appeared not to correlate with P300 alterations. CONCLUSIONS: These findings suggest the presence of central nervous pathological processes in NIDDM that affect higher brain functions, as assessed by P300 latencies. Our findings also suggest that microangiopathy and metabolic derangement during the preceding 4- to 8-week period may contribute in small part to the pathophysiology of this central nervous involvement.

Acoustic Stimulation↗

PubMed1996

Treatment with recombinant interferon-alpha 2a for patients with chronic hepatitis C: predictive factors for biochemical and virologic response. Osaka Liver Disease Study Group.

BACKGROUND: The heterogeneity of the hepatitis C virus (HCV) genome has been reported to be associated with the effectiveness of interferon therapy. We investigated the correlation of the viral and host factors, including the degree of sequence complexity of the HCV genome for responses to interferon-alpha in patients with chronic hepatitis C. METHODS: Ninety-seven patients received a 26-week course of recombinant interferon-alpha 2a therapy. The sequence complexity of the envelope 1-2 region was evaluated by polymerase chain reaction-mediated single-strand conformation polymorphism (PCR-SSCP) analysis. RESULTS: Of the 85 patients who completed the treatment, 31 (36%) achieved a sustained response, and 28 (33%) showed a sustained loss of HCV RNA. A low HCV RNA level, determined by the branched DNA probe assay, and serotype group 2 HCV correlated with a sustained response. In patients with serotype group 1 HCV of more than the threshold of the branched DNA probe assay, a band number on PCR-SSCP analysis of more than 2 could be associated with inefficacy of interferon therapy. Multivariate analysis in the 50 patients whose sera were available for all the virologic tests showed that only the HCV RNA level is independently predictive of a sustained response. CONCLUSIONS: Determination of the HCV RNA level is most important for predicting the response before interferon therapy. PCR-SSCP analysis may be useful as an additional test for patients with a high HCV RNA level of serotype group 1 HCV.

Adult↗