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Biomedical subjects

Y Doi

Publications and source records attributed to Y Doi.

At least 271 records · Page 15Linked to original sources
PubMed1995

Degree of external force to the left ventricle determines hemodynamic response to nitroprusside in failing hearts: comparison with the response to dobutamine.

Vasodilators frequently, although not always, increase cardiac output (CO) in patients with congestive heart failure (CHF) despite a decrease in left ventricular (LV) diastolic pressure. In patients with CHF, vasodilator-induced decrease in LV diastolic pressure without decrease in "preload" plays an important role in the vasodilator-induced increase in CO failure that may be caused by a vasodilator-induced reduction in external force to the LV. To clarify the hypothesis that a hemodynamic response to vasodilators depends on the degree of external force to the LV in failing hearts before drug administration and to examine whether the degree of the external force also affects a hemodynamic response to positive inotropic agents, we produced in 17 dogs two different conditions of LV dysfunction with high LV end-diastolic pressure (EDP: > or = 15 mm Hg), i.e., 1 with high right ventricular (RV) EDP (condition 1) and the other with lower RVEDP than condition 1 (condition 2), and compared hemodynamic effects of nitroprusside or dobutamine between these two conditions. Condition 1 was produced by the injection of a small dose of microspheres into the left coronary artery and intravenous infusion of dextran. Condition 2 was produced only by the injection of a large dose of microspheres. The nitroprusside-induced decrease in LVEDP was associated with a greater decrease in RVEDP and lesser decreases in mean left atrial pressure and LV end-diastolic diameter in condition 1 than in condition 2. CO increased in condition 1; however, CO then decreased in condition 2. The nitroprusside-induced changes in CO inversely correlated with those in RVEDP (r = 0.65, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

Morphology and biodegradability of a binary blend of poly((R)-3-hydroxybutyric acid) and poly((R,S)-lactic acid).

The miscibility, morphology, and biodegradability of a binary blend of bacterial poly((R)-3-hydroxybutyric acid)(P((R)-3HB);Mn = 300,000) with atactic poly((R,S)-lactic acid)(P((R,S)-LA);Mn = 9,000) were studied by means of differential scanning calorimetry, optical microscopy, scanning electron microscopy, and hydrolysis with an without enzyme. Differential scanning calorimetry revealed that a P((R)-3HB)-P((R,S)-LA) blend had a single glass-transition temperature for all proportions of the components. The spherulites of P((R)-3HB) were volume filled in the blend films, indicating the inclusion of amorphous P((R,S)-LA) within the spherulites. The spherulitic growth rate decreased with an increase in the content of P((R,S)-LA). These results indicate that the P((R)-3HB)-P((R,S)-LA) blend is miscible in the melt and in the amorphous state. The enzymatic hydrolysis of P((R)-3HB)-P((R,S)-LA) blend films was carried out at 37 degrees C for 19 h in 0.1 M potassium phosphate buffer (pH 7.4) with an extracellular poly(hydroxybutyrate) depolymerase from Alcaligenes faecalis T1. The rate of enzymatic surface erosion decreased with increasing P((R,S)-LA) content in the blend films. The simple hydrolysis of P((R)-3HB)-P((R,S)-LA) blend films without enzyme was also conducted at 37 degrees C in a 0.01 M potassium phosphate buffer (pH 7.4) for 150 days. The hydrolytic scission of P((R)-3HB) polymer chains was accelerated by blending with P((R,S)-LA). However, the rate of enzymatic hydrolysis was much faster than the rate of nonenzymatic hydrolysis.

Alcaligenes↗
PubMed1995

Amiloride-sensitive and HCO3(-)-dependent ion transport activated by aldosterone and vasotocin in A6 cells.

We studied the effects of aldosterone (Aldo) and arginine vasotocin (AVT) on ion transport of renal epithelial cell line (A6) by measuring short-circuit current (Isc). AVT induced a rapid, transient increase in Isc, followed by a decrease toward the baseline in cells untreated with Aldo. In cells treated with Aldo, Isc showed a biphasic response to AVT, i.e., both transient and sustained increases over 40 min after addition of AVT. The transient increase was composed only of amiloride-insensitive Isc regardless of Aldo treatment, whereas the sustained increase contained both amiloride-sensitive and amiloride-insensitive components. The main part of the amiloride-insensitive, sustained Isc depended on HCO3(-). In cells treated with Aldo for 1 day, removal of HCO3(-) in the bathing solution enhanced the amiloride-sensitive component and decreased the amiloride-insensitive one. These data suggest that 1) Aldo treatment is necessary for an AVT-induced sustained increase of Isc and 2) a HCO3(-)-dependent Isc mainly contributes to the sustained increase in amiloride-insensitive Isc.

Aldosterone↗
PubMed1995

Role of cathepsin B as prorenin processing enzyme in human kidney.

Renin is synthesized from an inactive precursor, prorenin, through cleavage at a pair of basic amino acids catalyzed by prorenin processing enzyme (PPE). A lysosomal protease, cathepsin B, has been suggested to be a strong candidate for PPE. However, there still remains a possibility that other protease(s) can also catalyze prorenin processing. We studied the subcellular distribution of PPE in human renal cortex using pure recombinant prorenin as a PPE assay substrate. PPE and renin activities, and cathepsin B activity and protein were colocalized in the lysosomal fraction. The PPE activity was completely inhibited by a cathepsin B specific inhibitor, CA074. Taken together with the immunohistochemical data showing that cathepsin B and PPE are colocalized in dense secretory granules of juxtaglomerular cells of kidney, we conclude that cathepsin B is the authentic PPE in human kidney.

Catalysis↗
PubMed1995

QT dispersion in acute myocardial infarction with special reference to left ventriculographic findings.

QT and QT dispersion, which is the time difference between QT maximum and QT minimum, were evaluated in 22 patients with anterior myocardial infarction approximately one month after onset. The purpose of this study was to observe how LV wall motion abnormally is related to these variables. Twenty age-matched patients without overt heart disease were also studied as a control group. QT and QT max in patients with acute myocardial infarction (AMI) were markedly prolonged compared to those in normal controls (472.8 +/- 48.0, 483.2 +/- 32.1 vs 390.2 +/- 18.8, and 418.0 +/- 21.0 msec, respectively). QT dispersion and QTc dispersion in patients with AMI were significantly more prolonged than in normal controls (111.2 +/- 33.9, (113.4 +/- 32.9 vs 54.3 +/- 15.0, and 60.3 +/- 17.2 msec, respectively). QT dispersion has a positive correlation with QT max in AMI patients. Ejection fraction (EF) of the left ventricle was relatively well maintained in cases where only one segment of the left anterior ventricular wall was impaired in its motion. It decreased, however, in accordance with the extent of wall motion abnormality QT max and QTc max were prolonged as the number of LV wall segments with impairment increased. This, however, was not statistically significant. QT dispersion and QTc dispersion had no relation to the extent of LV wall motion abnormality nor to EF of the left ventricle In conclusion, no definite relationships between QT dispersion (QTc dispersion) and EF of the left ventricle, or between these variables and the extent of left ventricular wall motion abnormality were found in patients with anterior myocardial infarction in our study. Although both QT max and QT dispersion were prolonged in patients with myocardial infarction, this suggests that electrical heterogeneity or regional variation in electrical ventricular recovery did not always parallel the severity of mechanical abnormality of the left ventricle.

Aged↗
PubMed1995

Pulmonary paragonimiasis with pleural effusion containing paragonimus ova: sonographical appearance of pleural effusion.

In the pleural effusion of a 46-year-old man with pulmonary paragonimiasis, numerous floating particles containing parasitic ova and granulation tissue were observed. The floating particles appeared as diffuse hyperechoic foci in the anechoic pleural effusion on ultrasonography. We concluded that rupture of the intrapulmonary paragonimiasis lesion into the pleural cavity caused the formation of these floating particles.

Humans↗
PubMed1995

[Diagnosis and prognosis of elderly patients with coronary artery disease: assessment with dipyridamole thallium imaging].

Noninvasive evaluation of coronary artery disease is difficult in elderly patients because of their limited exercise-capacity. The diagnostic and prognostic value of dipyridamole perfusion scintigraphy was assessed in 147 patients aged 65 years and older. All patients underwent coronary angiography. Initially, 32 patients had percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). The other 115 patients were first treated medically and followed for a mean of 29 +/- 22 months. Nine patients (7.9%) had cardiac events including cardiac death and coronary intervention (PTCA or CABG) during the follow-up. Dipyridamole perfusion scintigraphy was performed safely in all patients, whereas treadmill exercise testing could not be adequately performed in 24 patients, 18 of whom had multivessel disease. Multiple regression analysis showed that: fixed defect and reversible defect were powerful detectors of coronary lesions (p = 0.0001, p = 0.0027, respectively), all patients with fixed disease and 94% of patients with only reversible defect had significant coronary lesion; Diffuse slow washout and ST depression were statistically significant for detecting multivessel coronary lesions in patients with fixed disease (p = 0.0001, p = 0.017, respectively), the sensitivity and specificity of diffuse slow washout and/or ST depression for detecting multivessel coronary lesions ware 85% and 74%, respectively, and ST depression was statistically significant for detecting multivessel coronary lesions (p = 0.0002) in patients with only reversible defect, the sensitivity and specificity of ST depression were 88% and 64%, respectively. Cox survival analysis identified diffuse slow washout as the best predictor of future cardiac events among the scintigraphic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

[Significance of silent ischemia in dipyridamole perfusion scintigraphy: evaluation in patients with angina].

The significance of silent myocardial ischemia detected by dipyridamole perfusion scintigraphy was evaluated in 80 patients with stable angina and reversible defects (RD) but no infarction. The patients were divided into two groups: 26 patients with silent RD (62 +/- 7 years) and 54 patients with painful RD (65 +/- 7 years). Coronary risk factors, extent of coronary lesions, localization and degree of RD, and prognosis were compared. There was no significant difference in the incidence of coronary risk factors between these two groups, except for hyperlipidemia which was less frequently observed in patients with silent RD than in those with painful RD (8% vs 41%, p < 0.01). Coronary angiography revealed a higher prevalence of insignificant lesions or single vessel disease in patients with silent RD than in those with painful RD (73% vs 39%, p < 0.05). Dipyridamole perfusion scintigraphy revealed a lower degree of RD in patients with silent RD than in those with painful RD (4.4 +/- 3.3 vs 9.0 +/- 4.1 segments, p < 0.05), though there was no significant difference in the localization of RD between these two groups. Treadmill stress testing revealed a lower incidence of chest pain in patients with silent RD than in those with painful RD (26% vs 65%, p < 0.05), despite the mean exercise-duration being significantly longer in the former than in the latter (5.5 +/- 1.7 vs 3.9 +/- 1.7 min, p < 0.05). There was no significant correlation between the late peak serum ML-1 level and LV volume, and the size and motion of infarcted areas in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Changes in IL-6 and IL-8 after hepatectomy in patients with liver cirrhosis.

Changes in tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and interleukin-8 (IL-8) were investigated before and after hepatectomy in patients with or without liver cirrhosis (5 cases without liver cirrhosis and 14 cases with liver cirrhosis). Both the IL-6 and IL-8 values of the cirrhotic patients were significantly higher on the first postoperative day (POD) as compared with the non-cirrhotic patients. Overall, no significant correlation was found between peak values of IL-6 or IL-8 and blood loss or operating time. In the case of the cirrhotic patients, correlation of both IL-6 and IL-8 with operating time was significant at p < 0.05, gamma = 0.534 and 0.586, respectively. No correlation was found between blood loss and the peak value of IL-6, but significant correlation (gamma = 0.647, p < 0.05) was found between them in cirrhotic patients. There was no consistent increase in TNF-alpha and IL-1 beta following hepatectomy. These findings indicate that procedures undertaken to reduce the excessive production of these cytokines may be useful for preventing complications after hepatectomy in cirrhotic patients.

Carcinoma, Hepatocellular↗
PubMed1995

[Prognosis of patients with triple vessel disease and old myocardial infarction: relationship to the number of total coronary occlusions].

Patients with myocardial infarction (MI) and triple vessel coronary disease generally have poor prognoses. However, it is not known whether there are particular angiographic variables associated with the poor prognosis in MI patients with triple vessel disease. The angiographic variables for poor prognosis were investigated in 43 MI patients with triple vessel disease (32 men and 11 women, mean age 63 +/- 9 years) who were followed medically for a mean of 32 +/- 28 months. There were 13 cardiac deaths (30%) and 10 late-coronary artery bypass grafting (23%). Twenty patients were alive and well. The patients who died of cardiac causes had lower ejection fractions (42 +/- 18% vs 49 +/- 15%, p < 0.05), a higher prevalence of two vessel occlusion (77% vs 40%, p < 0.05), and a higher prevalence of coronary occlusion opposite the MI site (69% vs 25%, p < 0.01) when compared to survivors, although there were no significant differences in age, MI sites, or the prevalence of occlusion in the infarct-related artery. Multivariate analysis with the Cox proportional hazards model revealed that coronary occlusion opposite the MI site (hazards ratio 16.36) and an age of > or = 65 years (4.46) indicated a significantly high ratio. The hazard ratio of the ejection fraction and two vessel coronary occlusion were not significant. The poor prognosis of MI patients with triple vessel coronary disease may be related to impaired left ventricular function and to coronary occlusion opposite the MI site and greater age. This may have important clinical implications in the initial decision for interventional therapy.

Adult↗
PubMed1995

The contraction of small arteries in the perimetrium by presurgical medication with the luteinizing hormone-releasing hormone agonist to patients with leiomyomas: an electron and immunoelectron microscopy.

The remarkable contraction of small arteries occurred in the perimetrium of the uteri with leiomyomas by a presurgical medication P6th the luteinizing hormone-releasing hormone (LHRH) agonist (buserelin). The contracted vessels showed a significant increase in number of the Weibel-Palade (WP) bodies which occasionally underwent the degranulation and the discharge in a manner of exocytosis. By immunoelectron microscopy, localizations of endothelin (ET)-1 immunoreactive gold particles on the WP bodies as well as on cisterns of the rough endoplasmic reticulum (rER) and Golgi apparatus were pronounced in the buserelin-medicated group when compared to the non-medicated one. These findings indicate that the increase of the WP bodies storing ET-1, of which synthesis in the rER-Golgi system enhances, predominantly occurred in the small arteries in the perimetrium by the buserelin-medication prior to the hysterectomy. ET-1, released into the subendothelial layer, seems to play an important role in the contraction of the vascular media in a manner of paracrine.

Adult↗
PubMed1995

[The continent ileocecal pouch. The Mainz pouch I].

Since 1993 to July 1994, 374 patients underwent a Mainz Pouch procedure in their hospital. The follow up is between 4.2 +/- 2.6 years. The authors used this technique as well for bladder augmentation, bladder substitution as continent diversion. If possible, the appendix will be used for creating the continence system.

Adolescent↗
PubMed1995

[Vogt-Koyanagi-Harada disease with cerebellar lesions demonstrated on MRI: a case report].

We reported unique magnetic resonance imaging (MRI) findings of a 57-year-old Japanese man who was diagnosed as Vogt-Koyanagi-Harada disease. This patient presented with complaints of a transient severe headache followed by a bilateral loss of visual acuity and truncal ataxia. Magnetic resonance imaging revealed abnormal contrast enhancement of both the uveas and the cerebellar vermis corresponding to his neurological abnormalities. The distribution and the nature of the resolution of this unusual pattern of contrast enhancement suggested that these MRI findings might illustrate transient destruction of the blood brain barrier or vascular extravasations. Such events might be representative of pathophysiology involving the central nervous system that occurred in patients with Vogt-Koyanagi-Harada disease.

Cerebellar Ataxia↗
PubMed1994

Cloning and structural characterization of the human endothelial nitric-oxide-synthase gene.

Nitric oxide accounts for the activity of endothelium-derived relaxing factor, which seems to have an important role in vasodilation and inhibition of platelet aggregation. In endothelial cells, one isoform of nitric-oxide synthase is constitutively expressed. Analysis of the cDNA encoding the human endothelial nitric-oxide synthase revealed that the mRNA is 4.1 kb in size and that the translated protein consists of 1203 amino acids. We have cloned a genomic DNA encoding the human endothelial nitric-oxide synthase and analyzed the entire nucleotide sequence of the gene. The gene consists of 26 exons with a total size of 21 kb. The 5' flanking region of the gene lacks TATA boxes, but it contains putative Sp1-binding sites in (G+C)-rich regions. Of particular interest is the fact that a shear-stress-responsive element is located at position -985, which probably regulates the nitric-oxide-synthase gene in response to fluid mechanical forces at the transcriptional level in the vascular endothelium. Two minisatellite sequences are detectable in introns 2 and 8; a 32-bp consensus sequence repeats 38 times and a 57-bp consensus sequence repeats ten times. We found polymorphisms of the BamHI fragment containing the former minisatellite sequence in genomic DNA from pedigree family members. Furthermore, five tandem repeats of a 27-bp core consensus sequence and 35 repeats of a dinucleotide (CA) are located in introns 4 and 13, respectively. These repeat sequences will probably provide genetic markers for gene mapping and linkage analysis of inherited diseases including cardiovascular diseases.

Amino Acid Oxidoreductases↗
PubMed1994

Cloning and sequencing of hen magnum cDNAs encoding vitelline membrane outer layer protein I (VMO-I).

Two cDNAs encoding hen vitelline membrane outer layer protein I (VMO-I), which is classified as a new type of multi-beta-sheet assembly, were cloned and sequenced. Northern blot analysis using vmo-I cDNA as a probe showed the presence of three mRNA species. Strikingly, expression of these mRNAs was restricted to a specific region of the hen oviduct, the area joining the infundibulum to the magnum.

Amino Acid Sequence↗
PubMed1994

Crystal structure of vitelline membrane outer layer protein I (VMO-I): a folding motif with homologous Greek key structures related by an internal three-fold symmetry.

The crystal structure of vitelline membrane outer layer protein I (VMO-I), which is isolated from the vitelline membrane outer layer of hen's eggs, has been determined by the multiple isomorphous replacement method and refined to an R-factor of 18.8% at 2.2 A resolution. The main chain folds into an unusual structure that consists of three beta-sheets forming Greek key motifs, which are related by an internal pseudo three-fold symmetry. The internal portion surrounded by these three beta-sheets is filled with hydrophobic side chains. This conformational feature coincides with three internal repeats in the sequence. Although a similar fold exists in the second domain of delta-endotoxin, there are significant structural differences between the two proteins, with the three-fold symmetry being most regular in VMO-I.

Amino Acid Sequence↗