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Biomedical subjects

N Yamada

Publications and source records attributed to N Yamada.

At least 343 records · Page 19Linked to original sources
PubMed1997

Regenerative changes in median nerve defects using various rabbit skeletal muscles.

We examined the morphological changes of median nerve regeneration which situated to pass through degenerative latissimus dorsi and brachial triceps muscles in rabbits. Morphological observation was performed at 7, 14, 28, 45, 60 and 180 days after the creation of defect of the bilateral median nerves. Regenerative nerve fibers were observed in the residual tubes of left degenerative muscle bridges. In this respect the regenerative effect of the latissimus dorsi was better than that of the brachial triceps. These results suggest that regular and longer muscle fibers as those of latissimus dorsi may contribute to the effective regeneration of nerve.

Animals↗
PubMed1997

[An epidemiological study of HGV infection in an epidemic area of HCV infection in Japan].

We examined the prevalence on HGV infection in a hepatitis C epidemic area where 27.8% of inhabitants 40 years or over were anti-HCV positive. Of the 200 HCV RNA positive inhabitants 17(8.5%) were HGV RNA positive, although one of the 100 anti-HCV negative inhabitants in the same epidemic area, showed HGV RNA positive (1.0%). It might suggest that HGV infections in this HCV infection epidemic area have occurred in relation to HCV infection. The rate of abnormal transaminase in inhabitants HGV RNA and HCV RNA both positive was not different from that in inhabitants HGV RNA negative, but HCV RNA positive. This indicates that a further study is needed about the relationship between liver damage and HGV infection.

Biomarkers↗
PubMed1997

[A case report: surgical treatment of hypertrophic obstructive cardiomyopathy with acute hemodynamic deterioration due to chordae rupture of the mitral valve].

A 70-year-old woman was found to have new heart systolic murmur and was transferred to our hospital for the treatment of high fever and dyspnea. The chest X ray showed cardiomegaly (CTR 63%) and marked pulmonary congestion. The UCG revealed that there was no evidence of infective endocarditis, but there was hypertrophic obstructive cardiomyopathy with the left ventricular pressure gradient of 90 mmHg accompanied by mitral regurgitation (grade 3/4). Two weeks after the admission, mitral regurgitation progressed due to chordae rupture confirmed by UCG. Transaortic subvalvular myectomy and mitral valve replacement were underwent. Post-operative electrocardiogram demonstrated right and left anterior bandle branch block. Eleven months after the operation left ventricular outflow pressure gradient was not detected by echocardiogram and she has been in I/IV NYHA functional class.

Aged↗
PubMed1997

Detection of hepatitis G virus RNA in patients with hepatitis B, hepatitis C, and non-A-E hepatitis by RT-PCR using multiple primer sets.

Hepatitis G virus(HGV)/GB virus C(GBV-C) is a newly identified virus associated with human hepatitis. The preliminary prevalence studies of HGV infection in Japan were entirely based on the detection of HGV RNA by RT-PCR. However, the selection of the different primer sets in such assay may influence sensitivity of the test because of the extensive genetic heterogeneity of HGV, and influence the estimation of the prevalence of HGV. To address this potential problem, we designed two primer sets from well conserved domains in the 5'NC and NS5 regions of HGV genome, and tested them together with the NS3-derived primer set in RT-PCR for their ability to detect HGV RNA in serial dilution of synthetic viral RNA templates. Subsequently, we used these three primer sets to detect HGV RNA in the sera of 371 Japanese patients with hepatitis B, hepatitis C, and non-A-E hepatitis. The results indicated that the primer set derived from the 5'NC region appeared to be most effective in detecting HGV RNA. The results also showed that only two out of the 126 patients (1.6%) with non-A-E hepatitis were positive for HGV RNA although the RNA were detected more frequently in patients with hepatitis B (2/38; 5.3%) and hepatitis C (17/207; 8.2%), suggesting that HGV is not a common causative agent for non-A-E hepatitis in Japan.

Base Sequence↗
PubMed1997

[Exacerbation of atherosclerosis induced by hypertensive and hypercholesterolemic states--potential mechanisms and therapeutic implications].

Several experimental studies suggest many similarities between the effects of hypertension and hypercholesterolemia on the arterial wall. Both hypertension and hypercholesterolemia have proinflammatory effects on the artery. An increased production of oxygen-free radicals leads to increased transcription of redox-sensitive genes, which increases the expression of vascular cell adhesion molecule-1 (VCAM-1) in the endothelium, resulting in increased recruitment of monocytes to the endothelium. The oxidative stress on the arterial wall may occur in both hypertension and hypercholesterolemia, therefore a synergistic reaction between hypertension and hypercholesterolemia may play a role in the atherosclerotic process as common causal mechanisms. Among therapeutic strategies to protect the vascular injury in both hypertensive and hypercholesterolemic state, future research should include direct attack on these common mechanisms.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Probability maps of sequential glaucoma-scope images help identify significant change.

PURPOSE: The purpose of this study was to identify areas of the optic disc showing high variability of repeated depth measurements, and to minimize the effect of baseline variability in interpretation of possible change over time using the Glaucoma-Scope. METHODS: Seventy-four eyes from 70 subjects were analyzed with the Glaucoma-Scope. Three images were obtained on each of two separate sessions during the same day. At each location, the mean depth of the three images for each session was calculated to create a "baseline image." A contour map of standard deviation (SD) values at each topographic location was created for each subject reflecting local variability at different parts of the disc. The contour map and disc photograph were compared to determine what photographic features predicted high variability. A modified two-sample t-test was used at each topographic location to obtain p-values for the likelihood that a difference in mean depth between sessions was attributable to measurement variability alone. RESULTS: Contour plots of SD for most subject eyes showed high variability in steeply sloped areas of the disc and along large blood vessels, with low variability near the cup center. The use of probability plots for significance of depth changes between test sessions automatically accounted for increased pointwise variability. The proportion of topographic locations showing statistically significant change but attributable to chance variation when no true change has occurred approximated the predicted proportion based on our modified t-test model. CONCLUSION: A contour map of standard deviations of depth based on Glaucoma-Scope baseline images can identify areas of the disc with high variability. Statistical methods such as probability maps that account for local variability in the baseline image may be helpful in distinguishing true change from artefactual change over time.

Adolescent↗
PubMed1997

Lipoprotein abnormalities in non-insulin dependent diabetic patients with ischemic heart disease.

Plasma lipoproteins and clinical characteristics of non-insulin-dependent diabetic mellitus (NIDDM) patients with (n = 50) and without (n = 108) ischemic heart disease (IHD) were compared. The patients with IHD were older (64 +/- 9 vs 59 +/- 9 years, mean +/- SD, P < 0.01) and had a longer duration of diabetes (14 +/- 9 vs 11 +/- 8 years, P < 0.05). Lipids, lipoproteins and apolipoproteins were comparable in the two groups. The percent distribution of triglycerides (TG) in the very low density lipoprotein (VLDL) fraction was significantly higher (55 +/- 16 vs 50 +/- 17%, P < 0.05). The level of low density lipoprotein (LDL) (33 +/- 14 vs 39 +/- 15%, P < 0.05) and the apo E/VLDL-TG ratio (0.085 +/- 0.045 vs 0.12070.097, P < 0.01), however, was significantly lower in patients with IHD than in those without IHD. Multiple regression analysis also indicated that age, duration of diabetes, percent distribution of TG in VLDL, percent distribution of TG in LDL and the apo E/VLDL-TG ratio were significantly related to the presence of IHD. Hypertriglyceridemia, particularly when characterized by abnormalities of TG distribution, may play an important role in the development of IHD in NIDDM patients.

Aged↗
PubMed1997

Lipoprotein abnormalities in type 2 diabetic patients. Increased distribution of triglycerides (TG) in very low density lipoprotein (VLDL) and decreased apolipoprotein E/VLDL-TG ratio are risk for ischemic heart disease.

Plasma lipoproteins and clinical characteristics of type 2 diabetic patients with (n = 50) and without (n = 108) ischemic heart disease (IHD) were compared. The patients with IHD were older (64 +/- 9 vs 59 +/- 9 years, mean +/- SD, p < 0.01) and had a longer duration of diabetes (14 +/- 9 vs 11 +/- 8 years, p < 0.05). Lipids, lipoproteins and apolipoproteins were comparable in the two groups. The percent distribution of triglycerides (TG) in the very low density lipoprotein (VLDL) fraction was significantly higher (55 +/- 16 vs 50 +/- 17%, p < 0.05). The level of low density lipoprotein (LDL) (33 +/- 14 vs 39 +/- 15%, p < 0.05) and the apo E/VLDL-TG ratio (0.085 +/- 0.045 vs 0.120 +/- 0.097, p < 0.01), however, was significantly lower in patients with IHD than in those without IHD. Multiple regression analysis also indicated that age, duration of diabetes, percent distribution of TG in VLDL, percent distribution of TG in LDL and the apo E/VLDL-TG ratio were significantly related to the presence of IHD. Hypertriglyceridemia, particularly when characterized by abnormalities of TG distribution, may play an important role in the development of IHD in type 2 diabetic patients.

Aged↗
PubMed1996

Synergistic effects of transforming growth factor-beta on the expression of c-fms, macrophage colony-stimulating factor receptor gene, in vascular smooth muscle cells.

Vascular smooth muscle cells (SMC) transform to foam cells in the process of atherosclerosis. We have reported that SMC derived from the intima of atherosclerotic lesions express c-fms, macrophage colony-stimulating factor receptor gene, which is not normally expressed in medial SMC. In the present study, we demonstrated that transforming growth factor-beta (TGF-beta) synergistically induced expression of c-fms in the presence of platelet-derived growth factor-BB in human medial SMC, a level comparable to that observed in the intima. The induction of c-fms was not inhibited by protein kinase C (PKC) inhibitor, suggesting that TGF-beta induces c-fms via a PKC-independent pathway. These results suggest that TGF-beta plays an important role in the phenotypic change of smooth muscle cells to macrophage-like cells in the process of atherosclerosis.

Becaplermin↗
PubMed1996

Characterization of epileptiform field potentials recorded in the in vitro perirhinal cortex of amygdala-kindled epileptogenesis.

The perirhinal cortex (PRC) has recently been reported that the excitatory role of this area is important for the generation and the propagation of kindled seizures. In the present study, we investigated the extracellular electrophysiological properties of the circuitry which contribute to the propagation of seizures in the PRC, and examined the hypothesis that amygdala-kindling changes the electrophysiological nature of the rat PRC slice in vitro. Field potentials elicited in the PRC had extended duration (> 200 ms, most approximately equal to 1 s) with overlying spike components. The potentials showed strong synchronizing effect governed by an all-or-none rule. Although spontaneous epileptiform discharges that were equivalent in appearance to synaptically-activated field potentials were observed in the PRC of both amygdala-kindled and control rats, the number of slices showing spontaneous activity was significantly larger in the kindled group than in the control group (chi 2-test, P < 0.01). The occurrence of tetanus-induced afterdischarges in kindled rats was significantly higher than in control rats (chi 2-test, P < 0.01). The afterdischarge durations of control slices were generally short and the afterdischarges did not consist of the typical "tonic-clonic' phases. However, the occurrence of the electrographical seizure in the high K+ ACSF were not affected by amygdala-kindling operation. These results indicate that amygdala-kindling lowers the threshold for transsynaptic excitability and enhances the synchronized activity of the PRC induced by episodic proconvulsive manipulations such as tetanus stimulation.

Amygdala↗
PubMed1996

Sequence of hepatitis G virus genome isolated from a Japanese patient with non-A-E-hepatitis: amplification and cloning by long reverse transcription-PCR.

The nucleotide sequence of hepatitis G virus (HGV) genome was determined by analysis of cDNA clones obtained by long reverse transcription-polymerase chain reaction (long RT PCR) and 5'- and 3'-rapid amplification of cDNA ends (RACE) from a Japanese patient (Iw) with non A-E hepatitis. The HGV-Iw genome, consisting of 9375 nucleotides, contains a long open reading frame encoding 2873 amino acid residues. Comparison of HGV-Iw with two American isolates of HGV and one African isolate of GB virus C (GBV-C) indicates that although the nucleotide sequences of these isolates were considerably divergent (86.2% to 93.3%), the deduced amino acid sequences shared an extremely high degree of identity (96.1% to 100%). It was also found that HGV-Iw was more closely related to the HGV isolates from USA than to the GBV-C isolate from Africa.

Cloning, Molecular↗
PubMed1996

Induction of macrophage colony-stimulating factor receptor (c-fms) expression in vascular medial smooth muscle cells treated with heparin binding epidermal growth factor-like growth factor.

Vascular smooth muscle cells migrate, proliferate, and transform to foam cells during the atherosclerotic process. We have reported that smooth muscle cells derived from the intima of atherosclerotic lesions express the proto-oncogene c-fms and a scavenger receptor, which are not normally expressed in normal medial smooth muscle cells. In the present study, we demonstrated that heparin binding epidermal growth factor-like growth factor (HB-EGF) induced the expression of c-fms and the scavenger receptor in normal human medial smooth muscle cells to the level observed in the intima. The expression of c-fms was partially inhibited by a protein kinase C inhibitor, suggesting that HB-EGF induces c-fms via pathways that are both dependent on and independent of protein kinase C. By contrast, most of the scavenger receptor induction by HB-EGF was suppressed by protein kinase C inhibitors. These results indicate that two characteristic genes of monocyte-derived macrophages were induced by HB-EGF via different mechanisms. The alteration of gene expression in response to HB-EGF may play an important role in the phenotypic change of smooth muscle cells to macrophage-like foam cells during the atherosclerotic process.

Blotting, Western↗
PubMed1996

Role of the low density lipoprotein (LDL) receptor pathway in the metabolism of chylomicron remnants. A quantitative study in knockout mice lacking the LDL receptor, apolipoprotein E, or both.

Two receptor pathways are thought to mediate the hepatic clearance of chylomicron remnants, (i) the low density lipoprotein receptor (LDLR) pathway and (ii) non-LDLR pathway. The current study was undertaken to quantitatively assess the contribution of each receptor pathway to hepatic catabolism of chylomicron remnants, by using mice that are deficient in apolipoprotein E (apoE) (apoE(-/-)), the LDLR (LDLR(-/-)), and both (apoE(-/-);LDLR(-/-)). Vitamin A fat tolerance tests showed that the area under the curves of the plasma excursions of retinyl ester in the LDLR(-/-), apoE(-/-), and apoE(-/-);LDLR(-/-) mice were 4, 12, and 12 times larger than those in wild-type mice. The retinyl ester accumulated in the plasma of the LDLR(-/-) mice was distributed in larger subfractions of triglyceride-rich lipoproteins, chylomicrons through very low density lipoprotein-C. These results indicate that the LDLR constitutes the major pathway for the clearance of retinyl ester. In support of this, agarose gel electrophoresis revealed that an oral fat load resulted in retention of chylomicrons in the LDLR(-/-) mice, which was not seen in wild-type mice. The observation that the apoE(-/-) mice showed larger retinyl ester excursion than LDLR(-/-) mice indicates that an apoE-dependent non-LDLR pathway is involved in the rest of the clearance of the retinyl ester. Together, we conclude that the LDLR pathway plays a significant role in the chylomicron remnant metabolism in mice fed a normal chow.

Animals↗