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Biomedical subjects

H Yoshida

Publications and source records attributed to H Yoshida.

At least 721 records · Page 40Linked to original sources
PubMed1998

Vasodilatory effects of B-type natriuretic peptide are impaired in patients with chronic heart failure.

BACKGROUND: B-type natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) are secreted from the heart and are thought to be equally important factors in the regulation of vascular tone in health and in congestive heart failure (CHF). However, no studies directly compare vasodilator effects of these peptides in healthy subjects and in patients with CHF. METHODS: Plethysmography was used to determine the vasodilatory effects of BNP and to compare these to the effects of ANP in patients with CHF (n = 15) and age-matched healthy subjects (n = 16). Graded doses of ANP and BNP (8, 16, 32, and 48 pmol/min per 100 ml of tissue volume for both) were administered randomly into the brachial artery. Forearm blood flow (FBF) was measured, and cyclic GMP (cGMP) spillover was calculated. RESULTS: Responses in FBF to both peptides in CHF were significantly lower than those of healthy subjects (BNP p < 0.05; ANP p < 0.01). Similarly, forearm spillover of cGMP was significantly lower in CHF than in healthy subjects (BNP p < 0.05; ANP p < 0.01). When vascular responses in healthy subjects were compared between BNP and ANP, BNP-induced changes in FBF (p < 0.05) and forearm cGMP spillover (p < 0.01) were significantly less than changes induced by ANP. In CHF, though, FBF change and cGMP spillover induced by the two peptides were not significantly different. CONCLUSIONS: These results suggest that the metabolism and action of these natriuretic peptides in CHF may differ from the healthy state.

Aged↗
PubMed1998

Remnant-like particle cholesterol is a major risk factor for myocardial infarction in vasospastic angina with nearly normal coronary artery.

We investigated the association of remnant-like particle cholesterol (RLP-C), with vasospastic angina (VSA). We selected 66 subjects with nearly normal coronary artery as a control group, and 74 VSA with nearly normal coronary artery, of whom 19 had prior myocardial infarction (MI). Coronary risk factors, triglyceride, lipoproteins and apolipoproteins were evaluated using stepwise discriminant analysis, smoking was the only discriminator of the control group from VSA and RLP-C was the only discriminator of VSA with MI from VSA without MI. In comparison between VSA with and without MI, using stepwise logistic regression analysis, the only significant variable was RLP-C, and odds ratio of RLP-C for MI was 1.59. Thus, RLP-C is a major discriminator of VSA with MI and appears to be a major risk factor for MI in VSA.

Adult↗
PubMed1998

Beneficial effect of gemfibrozil on the chemical composition and oxidative susceptibility of low density lipoprotein: a randomized, double-blind, placebo-controlled study.

Previous reports have shown that administration of fibrates can reduce coronary events and also improve plasma lipid levels. Oxidative modification of low density lipoprotein has been implicated in the pathogenesis of atherosclerosis, and the resistance of low density lipoprotein (LDL) to in vitro oxidation has been found to be correlated with the extent of atherosclerosis. We performed a double-blind, placebo-controlled intervention trial to establish whether gemfibrozil could improve resistance of LDL to oxidation in patients with hyperlipidemia. Patients were randomly assigned to treatment with gemfibrozil (450 mg, twice a day, n = 10) or placebo (n = 9) for 8 weeks. Blood samples were obtained after an overnight (12 h) fast. Gemfibrozil administration significantly reduced total plasma cholesterol and triglyceride levels and changed the LDL from small, dense particles (pattern B, < or = 25.5 nm) to larger, more buoyant particles (pattern A, > 25.5 nm). Gemfibrozil significantly increased the lag time of LDL oxidation in vitro by 18.2% from 45.5 +/- 8.0 min at week 0 to 53.4 +/- 11.4 min at week 8, but did not change LDL vitamin E and beta-carotene concentrations. Surprisingly, gemfibrozil significantly decreased LDL lipid peroxides by -33.1% and increased the LDL vitamin E/lipid peroxide ratio by 67.6% from 1.3 +/- 0.5 at week 0 to 2.1 +/- 0.9 at week 8. These results demonstrate that gemfibrozil treatment can render LDL less susceptible to oxidative modification while reducing plasma cholesterol and triglyceride and improving LDL subclass pattern. This antioxidative effect of gemfibrozil on LDL may be one of the factors which could delay the progression of atherosclerosis.

Adult↗
PubMed1998

Prolonged decreases in plasma nitrate levels at early postoperative phase after hepato-pancreato-biliary surgery.

Nitric oxide (.NO) is known to influence circulatory, neural, immunologic, and metabolic alterations. To evaluate the clinical significance of .NO production under surgical stress, serial measurements of plasma nitrite plus nitrate levels were performed in 45 surgical patients. Group A included 19 patients who underwent major surgery with uneventful postoperative courses. Group B included 18 patients who underwent laparoscopic cholecystectomy. Group C included 8 patients whose surgery was complicated by intra-abdominal abscesses. Eight healthy volunteers served as controls. Plasma nitrate levels were determined with a redox chemiluminescence .NO analyzer and coincided with measurements made by high-performance liquid chromatography (r = 0.868, p < 0.0001, 58 samples). During laparotomy, arterial nitrate levels correlated well with peripheral, portal, and hepatic venous nitrate levels (r = 0.966, 0.938, and 0.949, respectively; p < 0.0001). A significant decrease in nitrate from preoperative levels in groups A (postoperative day (POD) 1 and 3; p < 0.0005) and B (POD 1, p < 0.0001) was observed; nitrate levels in group C did not decrease for 14 days after surgery. Plasma nitrate levels in groups A and B were significantly different (POD 1 through 6, p < 0.05) and at POD 3 were significantly lower in group A (p < 0.005). Plasma nitrate levels measured before and after fasting or food intake were not significantly different. These results suggest that surgical stress leads to a decrease in the end product of .NO in the whole body, and that the greater the surgical stress the longer the duration of decreased .NO production.

Adult↗
PubMed1998

Pathologically-proven intracranial germinoma treated with radiation therapy.

BACKGROUND AND PURPOSE: A retrospective multi-institutional study was conducted to survey what percentage of intracranial germinomas were treated with pathological confirmation before radiotherapy and to investigate the influence of field selection on outcome. MATERIALS AND METHODS: Thirty-seven percent of patients (41 of 110 patients) were pathologically confirmed before radiotherapy during the past 16 years at eight institutions in Northern Japanese prefectures. Pathological confirmation was obtained in 26, 37 and 53% of cases during 1978-1983, 1984-1989 and 1990-1994, respectively. All 110 patients were examined using computed tomography (CT) scans. Among the 41 patients with pathologically confirmed germinoma, radiation fields were craniospinal in 23 patients, whole-brain in 10 patients and local without ventricle inclusion in eight patients. RESULTS: For the 41 patients with pathologically confirmed germinoma, the actuarial and cause-specific survival rates were 91/94% at 5 years and 87/90% at 10 years, respectively. The relapse-free survival rate at 10 years was 90. 76 and 22% for the craniospinal field, whole-brain field and local field without ventricle inclusion, respectively. CONCLUSION: Pathological confirmation was obtained in only 37% of CT-scan era cases, although the confirmations were more commonly carried out later in the study period. Limited local irradiation alone without ventricle inclusion cannot be recommended for localized tumors even with the help of CT scanning.

Adolescent↗
PubMed1998

Retrospective multi-institutional study of radiotherapy for intracranial non-germinomatous germ cell tumors.

The treatment outcome of 24 patients with pathologically-proven non-germinomatous germ cell tumor was retrospectively investigated to determine the effectiveness of radiotherapy. The patients were divided into three groups as follows: group 1, five patients with mature teratoma with or without germinoma; group 2, six patients with immature teratoma with or without germinoma; group 3, 13 patients with other highly malignant tumors. The overall actuarial survival and relapse-free rates at 5 years were 82% and 59%, respectively, with a median follow-up period of 62 months. The actuarial relapse-free rate at 5 years was 100% for group 1, 63% for group 2 and 44% for group 3. There was no difference in the relapse-free rates between total resection and partial resection. Usage of chemotherapy was adversely related to survival probably due to selection bias. No local failure was observed with 10 Gy or more for group 1,40 Gy or more for group 2 and 54 Gy or more for group 3. In groups 1 and 2, there was no spinal relapses without craniospinal irradiation. In group 3, three of eight patients who did not receive craniospinal irradiation and none of five patients who received craniospinal irradiation experienced spinal relapse. In conclusion, highly malignant GCTs show a high incidence of spinal metastasis and craniospinal irradiation may reduce the risk of spinal metastasis. Radiation dose and volume are to be determined according to the histopathological aggressiveness.

Adolescent↗
PubMed1998

Ultrasonographic evaluation of small cervical lymph nodes in head and neck cancer.

To establish sonographic criteria for differentiating metastasis and nonmetastasis in small cervical lymph nodes, correlations between sonographic parameters and histological diagnosis were statistically examined in 117 lymph nodes with maximal diameter of up to 10 mm in the sonographic findings, consisting of 26 metastatic and 91 nonmetastatic nodes. The equations obtained with logistic regression analysis showed lambda predictive values of -1.5 and 0.5 as effective cutoff-point criteria, and were considered to be a reliable indicator for differentiating small nodes with predictive values outside of -1.5 < lambda < 0.5. The sensitivity, specificity and accuracy with predictive values outside of -1.5 < lambda < 0.5 were 83%, 97% and 95%, respectively.

Adult↗
PubMed1998

Comparison of effects of enalapril and nitrendipine on cardiac sympathetic nervous system in essential hypertension.

OBJECTIVES: The purpose of this study was to assess the effects of enalapril and nitrendipine on the cardiac sympathetic nervous system. BACKGROUND: Angiotensin-converting enzyme inhibitors and long-acting calcium channel blockers have been widely used in the treatment of cardiovascular diseases, in some of which sympathetic overactivity plays a major role in the pathophysiology and prognosis. However, little information is available on the effects of these drugs on the cardiac sympathetic nervous system. METHODS: 123I-metaiodobenzylguanidine (MIBG) cardiac imaging was performed before and 3 months after drug administration in 46 patients with mild essential hypertension. Twenty-two patients were treated with 5 to 10 mg of enalapril once a day, and the other 24 with 5 to 10 mg of nitrendipine once a day. For comparison, 20 normotensive subjects were also studied. RESULTS: There were no significant differences between the basal characteristics in the 2 hypertensive groups. In both hypertensive groups, both systolic and diastolic blood pressures were significantly reduced to similar levels after the 3-month drug treatment. Before the drug treatment, the 2 hypertensive groups had a significantly higher washout rate and lower MIBG uptake than the normotensive subjects. The heart-to-mediastinum ratio significantly increased (p < 0.0001), with decreased (p < 0.002) washout rate after drug treatment in the enalapril group, but with no significant changes in the nitrendipine group. CONCLUSION: Enalapril could suppress cardiac sympathetic activity and nitrendipine had no effect on it. The knowledge of antihypertensive drugs on the cardiac sympathetic nervous system appears to be helpful in selecting appropriate treatment in cardiovascular diseases.

3-Iodobenzylguanidine↗
PubMed1998

Left ventricular geometric patterns and QT dispersion in borderline and mild hypertension: their evolution and regression.

To investigate whether QT dispersion increases in borderline and mild hypertension during a longitudinal observation of > 3 years and whether it is improved with medications, left ventricular geometric patterns and QT dispersion were studied with special regard to their longitudinal changes in 85 male borderline and mild hypertensive subjects with left ventricular mass index < 125 g/m2. These subjects were followed for > 3 years without medication. Thirty-two patients with a left ventricular mass index > 125 g/m2 at the end of follow-up period were further observed using antihypertensive drugs for an additional 3 years. Echocardiograms and electrocardiograms were obtained at the beginning and end of the follow-up period. At the end of the follow-up period, subjects were classified into four groups based on ventricular geometric patterns determined by left ventricular mass index and relative wall thickness in diastole. The QT dispersion was greater in patients with concentric hypertrophy (56+/-18 msec) than in patients with normal geometry (41+/-17 msec) (P < .05) and increased significantly in the former group during the follow-up period. After medication, the left ventricular mass index regressed and the QT dispersion decreased (from 55+/-21 to 50+/-26 msec, P < .01) in these patients. Thus, these findings suggest that changes in the QT dispersion reflect both concentric evolution and regression of left ventricular hypertrophy.

Adult↗
PubMed1998

Effects of an ACE inhibitor and a calcium channel blocker on cardiovascular autonomic nervous system and carotid distensibility in patients with mild to moderate hypertension.

We investigated the relationship between cardiovascular autonomic nervous system function and carotid arterial distensibility during treatment with an angiotensin converting enzyme inhibitor (derapril) or a calcium channel blocker (manidipine) for hypertension. In 37 patients with hypertension, autonomic function was assessed by heart rate variability and baroreceptor sensitivity using phenylephrine injection. Left ventricular mass index and carotid arterial distensibility were assessed by ultrasound examinations. Before the medication, both baroreceptor sensitivity and heart rate variability correlated with carotid arterial distensibility, but not with left ventricular mass index by multiple regression analysis. Subsequently, patients were randomly allocated into two groups, derapril (n = 18) and manidipine (n = 19) for 20 weeks. At the end of the study, the change in baroreceptor sensitivity correlated with change in carotid arterial distensibility (r = 0.41, P < .05), but not with change in left ventricular mass index. Although derapril and manidipine decreased blood pressure and left ventricular mass index to the same extent, the former improved heart rate variability, baroreceptor sensitivity (5.0 +/- 1.9 --> 5.6 +/- 2.0 msec/mm Hg), and carotid arterial distensibility (2.1 +/- 0.8 --> 2.5 +/- 1.0 %kPa), but the latter did not improve them at all. Thus, impairment of the autonomic balance was related to the impairment of carotid arterial distensibility in hypertension; derapril, but not manidipine, significantly improved these abnormalities.

Aged↗
PubMed1998

Parosteal chondrosarcoma attached to the hyoid bone. A case report.

A parosteal chondrosarcoma with low-grade malignancy attached to the hyoid bone in a 66-year-old man is reported. The tumor was considered to present a low-grade malignancy because slight invasion into the surrounding soft tissues and rapid growth were observed. Four years after initial surgery he had a local recurrence. To the best of our knowledge, this is the first reported case of parosteal chondrosarcoma in this location.

Aged↗
PubMed1998

The transcription factor NF-ATc1 regulates lymphocyte proliferation and Th2 cytokine production.

NF-ATc1 is a member of a family of genes that encodes the cytoplasmic component of the nuclear factor of activated T cells (NF-AT). In activated T cells, nuclear NF-AT binds to the promoter regions of multiple cytokine genes and induces their transcription. The role of NF-ATc1 was investigated in recombination activating gene-1 (RAG-1)-deficient blastocyst complementation assays using homozygous NF-ATc1-/- mutant ES cell lines. NF-ATc1-/-/RAG-1-/- chimeric mice showed reduced numbers of thymocytes and impaired proliferation of peripheral lymphocytes, but normal production of IL-2. Induction in vitro of Th2 responses, as demonstrated by a decrease in IL-4 and IL-6 production, was impaired in mutant T cells. These data indicate that NF-ATc1 plays roles in the development of T lymphocytes and in the differentiation of the Th2 response.

Animals↗
PubMed1998

In vitro generation of lymphohematopoietic cells from endothelial cells purified from murine embryos.

We have investigated the lymphohematopoietic potentials of endothelial cells (EC) and hematopoietic cells (HPC) sorted from embryos. Expression of VE-cadherin, CD45, and Ter119 was used to distinguish EC (VE-cadherin+CD45-Ter119-) from HPC (VE-cadherin-CD45+). Thus defined, EC population takes up acetylated LDL and coexpresses CD31, Flk1, and CD34. In E9.5 embryos, EC from yolk sac (YS) and the embryo proper generate blood cells, including lymphocytes. Thus, lymphohematopoietic EC do exist in the embryo, and they are generated both in YS and the embryo proper. On the other hand, HPC with lymphopoietic potency appear first in the embryo proper. These findings implicate involvement of multiple environmental cues for acquiring lymphopoietic competency during differentiation of HPC.

Animals↗
PubMed1998

MoldaNet: a network distributed molecular graphics and modelling program that integrates secure signed applet and Java 3D technologies.

MoldaNet is a molecular graphics and modelling program that integrates several new Java technologies, including authentication as a Secure Signed Applet, and implementation of Java 3D classes to enable access to hardware graphics acceleration. It is the first example of a novel class of Internet-based distributed computational chemistry tool designed to eliminate the need for user pre-installation of software on their client computer other than a standard Internet browser. The creation of a properly authenticated tool using a signed digital X.509 certificate permits the user to employ MoldaNet to read and write the files to a local file store; actions that are normally disallowed in Java applets. The modularity of the Java language also allows straightforward inclusion of Java3D and Chemical Markup Language classes in MoldaNet to permit the user to filter their model into 3D model descriptors such as VRML97 or CML for saving on local disk. The implications for both distance-based training environments and chemical commerce are noted.

Computer Graphics↗
PubMed1998

Interleukin-8 production in primary cultures of human gastric epithelial cells induced by Helicobacter pylori.

Interleukin-8 (IL-8) production by the gastric mucosa is increased in Helicobacter pylori infection. Previous studies indicated that H. pylori induces IL-8 synthesis in cancer cell lines, and the ability of H. pylori to stimulate IL-8 production is supposed to be associated with cagA and other cag pathogenicity island genes, including picB gene. In the present study, we investigated the induction of IL-8 in primary cultures of normal human gastric epithelial cells to elucidate the IL-8 induction by wild type strains and by the picB knockout strain. Human gastric epithelial cells were obtained from surgically resected specimens from four patients. Three H. pylori strains (TN2F4; type 1 clinical isolate, TN2F4m1; isogenic picB mutant of TN2F4, Tx30a; type 2 strain) were cocultured with the normal gastric epithelial cells or the transformed MKN-28. IL-8 levels in culture medium were determined by enzyme immunoassay. Human gastric epithelial cells produced IL-8 at a 10-50 times higher level than MKN-28 did when cocultured with TN2F4. The mutant TN2F4m1 induced IL-8 at significantly lower levels than the parent strain. Cells from four patients behaved similarly on IL-8 production. The results of the present study demonstrated the induction of IL-8 in normal gastric epithelial cells, suggesting that picB gene product may play an essential role in vivo.

Bacterial Proteins↗