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Biomedical subjects

Y Doi

Publications and source records attributed to Y Doi.

At least 307 records · Page 17Linked to original sources
PubMed1993

Regional thallium-201 washout and myocardial hypertrophy in hypertrophic cardiomyopathy and its relation to exertional chest pain.

The mechanism of exertional chest pain in hypertrophic cardiomyopathy is uncertain, but may relate to myocardial ischemia. To study the mechanism of exertional chest pain in hypertrophic cardiomyopathy, dipyridamole-stress thallium-201 single-photon emission computed tomography was performed in 82 consecutive patients, and the 3-hour washout of thallium in relation to the tomographic image, regional wall thickness on echocardiography, and other clinical findings was analyzed. There was a weak inverse correlation of regional washout and wall thickness in 298 analyzed quadrant areas (r = -0.29; p = 0.0001). Twenty-five patients (31%) had history of exertional chest pain, and showed a significantly lower total washout and greater maximal left ventricular wall thickness than did those without chest pain (32 +/- 10% vs 37 +/- 9% [p = 0.03], and 27 +/- 7 vs 23 +/- 7 mm [p = 0.03], respectively). Even in mildly and nonhypertrophied areas, patients with chest pain had a significantly lower regional washout than did those without pain (33 +/- 10% vs 38 +/- 9%; p = 0.02), despite similar left ventricular wall thickness (12 +/- 2 vs 11 +/- 3 mm; p = NS). Reduced washout was strongly associated with exertional chest pain and was observed in myocardial regions that had normal as well as increased thickness, which indicates that this abnormality of thallium kinetics is a function of the disease process and not the magnitude of left ventricular hypertrophy.

Adolescent↗
PubMed1993

Importance of left ventricular minimal pressure as a determinant of transmitral flow velocity pattern in the presence of left ventricular systolic dysfunction.

OBJECTIVES: This study was designed to assess whether the transmitral flow velocity pattern provides an estimation of left atrial pressure irrespective of the presence of left ventricular systolic dysfunction and, if not, to clarify the mechanism. BACKGROUND: The pulsed Doppler transmitral flow velocity pattern, particularly peak early diastolic filling velocity, has been shown to change in parallel with left atrial pressure. However, extremely elevated left atrial pressure in association with heart failure does not necessarily cause an increase in peak early diastolic filling velocity in patients. METHODS: Left atrial pressure was elevated with intravenous saline infusion in 11 dogs (normal left ventricular function group) and hemodynamic, transesophageal Doppler echocardiographic and M-mode echocardiographic variables were recorded at three different loading levels. In another 12 dogs, left atrial pressure was elevated by production of left ventricular systolic dysfunction with the stepwise injection of microspheres into the left coronary artery (left ventricular dysfunction group) and the same set of recordings was obtained at three different levels of dysfunction. RESULTS: Peak early diastolic filling velocity increased with left atrial pressure in the normal left ventricular function group and correlated with mean left atrial pressure (r = 0.61, p < 0.01) and early diastolic left atrial to left ventricular crossover pressure (r = 0.71, p < 0.01). In contrast, peak early diastolic filling velocity did not increase with left atrial pressure in the left ventricular dysfunction group and did not correlate with mean left atrial pressure (r = -0.05) or the crossover pressure (r = 0.06). Peak early diastolic filling velocity correlated well with the difference between the crossover pressure and left ventricular minimal pressure in the left ventricular dysfunction group (r = 0.64, p < 0.01). In contrast to peak early diastolic filling velocity, deceleration time of the early diastolic filling wave correlated with mean left atrial pressure and the crossover pressure irrespective of the primary cause of preload alteration (r = -0.54, r = -0.59, p < 0.01 respectively, n = 69 for all data). CONCLUSIONS: Preload dependency of the Doppler transmitral flow velocity pattern is hampered if an increase in left atrial pressure is due to left ventricular systolic dysfunction. In this setting, the increase in left ventricular minimal pressure due to left ventricular systolic dysfunction cancels the effect of the increase in left atrial pressure on the flow velocity pattern.

Animals↗
PubMed1993

Vasocontractions of the in-vitro toad aortas induced by endothelin-1 and sarafotoxin-S6b.

Dose-dependent tension curves were recorded from the in vitro toad aortas by administration of endothelin-1 and sarafotoxin-S6b. The maximal contractile tensions by both drugs were evoked at a 10(-8) M concentration. By a single dose application (10(-8) M) of endothelin-1 and sarafotoxin-S6b to both endothelium-preserved and denuded vessels, the induction of the endothelium-dependent vasocontraction occurs after 2 min of administration. Ultrastructural changes of Weibel-Palade bodies such as decrease in electron density, swelling with a wide peripheral halo, and expulsion of their contents in a manner of exocytosis become evident within 2 min after administration of these drugs. These findings indicate that some vasocontractile substances in Weibel-Palade bodies are extracellularly discharged by endothelin-1 and sarafotoxin-S6b.

Animals↗
PubMed1993

Immunoelectron microscopy on the localization of endothelin in the umbilical vein of perinatal rabbits.

Immunoelectron microscopic localization of endothelin (ET) using the mouse monoclonal anti-ET sera was performed on the pre- and postnatal rabbit umbilical vein during stages when Weibel-Palade (WP) bodies increase in number in the endothelial cells. The immunoreactions are localized in the rough endoplasmic reticulum, Golgi cisterns, and WP bodies that are actively segregated from the Golgi apparatus. After degranulation and extracellular release of WP bodies was induced by compound 48/80, heavy immunoreactions were seen in both vascular lumen and cytoplasm near the degranulated WP bodies. These results indicate that ET is stored in WP bodies after segregation from the Golgi apparatus and released from the endothelial cells concomitantly with other components of these granules by exocytosis. Because the immunoreactions are also seen in pinocytotic vesicles that are occasionally in contact with WP bodies, it seems likely that WP bodies are also involved in the uptake and storage of ET from blood plasma.

Animals↗
PubMed1993

Immobilized DPP and other proteins modify OCP formation.

Osteonectin, gamma-carboxyglutamic acid-containing (Gla) protein, and dentin phosphoprotein were covalently attached to sepharose beads and inoculated in solutions at two different degrees of supersaturation with respect to both octacalcium phosphate (OCP) and hydroxyapatite. In both solutions, the inhibitory activity towards de novo formation of calcium phosphate that these proteins display when freely dissolved in solution was completely eliminated when they were immobilized on the sepharose at concentrations of up to 5 micrograms/mg wet beads. In the solution that was more highly supersaturated with respect to OCP, the immobilized dentin phosphoprotein, moreover, was found to induce de novo formation of OCP in proportion to the concentration of the protein immobilized. For example, at 10 micrograms/ml of the immobilized dentin phosphoprotein, the induction period was reduced more than 50%. However, in the solution considerably less supersaturated with respect to OCP, none of the immobilized proteins were capable of inducing OCP or apatite deposition. These findings suggest that the immobilized dentin phosphoprotein could work as a nucleating substrate for the OCP phase in solutions where calcium and phosphate concentrations are sufficiently higher than equilibrium saturation levels for the OCP phase.

Animals↗
PubMed1993

Congenital sarcoma in the terminal ileum histologically resembling clear cell sarcoma of the kidney: a case report with an immunohistochemical study.

We report a case of a newborn female with a rare tumor, a congenital sarcoma, presenting as an abdominal mass. Laparotomy demonstrated the tumor arising from the wall of the terminal ileum. Histologically, the tumor tissue was indistinguishable from clear cell sarcoma of the kidney and was composed of proliferating cells with poorly stained cytoplasm divided into nests or cords by arborizing vasculature. Immunohistochemical staining revealed that the neoplastic cells had a phenotype similar to metanephric blastemal cells of fetal kidney, ie, positive for vimentin and CD24 but negative for cytokeratin and CD9. The results suggest that this congenital tumor may originate from primitive mesenchymal cells phenotypically related to cells present in the fetal kidney.

Diagnosis, Differential↗
PubMed1993

Biosynthesis of poly(3-hydroxy-alkanoates) in Pseudomonas aeruginosa AO-232 from 13C-labelled acetate and propionate.

Pseudomonas aeruginosa AO-232 produced poly(3-hydroxyalkanoates) (P(3HA)) containing monomer units of even carbon numbers C6, C8, C10 and C12, when sodium acetate was fed as the sole carbon source. In contrast, the P(3HA) produced from sodium propionate was composed of seven different 3HA units ranging from C6 to C12. The pathways of P(3HA) synthesis were investigated by using 13C-labelled acetate and propionate as the carbon sources. The 13C-labelled carbonyl carbon of [1-13C] acetate was selectively incorporated into the odd-numbered carbon atoms of 3HA units, while the methyl carbon of [2-13C] acetate was introduced into the even-numbered carbon atoms of 3HA units. The 13C-labelled carbonyl carbon of [1-13C] propionate was selectively incorporated into the third carbon atoms from methyl carbons in the 3HA units of C7, C9 and C11. The synthesis of P(3HA) from acetate or propionate was related to de novo fatty acid biosynthesis.

Acetates↗
PubMed1993

Enzymatic degradation of poly(hydroxyalkanoates) by Pseudomonas pickettii.

A bacterium capable of degrading poly(3-hydroxybutyrate) [P(3HB)] was isolated from laboratory media and identified as Pseudomonas pickettii. The strain P. pickettii excreted an extracellular poly(hydroxyalkanoate) (PHA) depolymerase and grew on P(3HB) as the sole carbon source. P. pickettii also grew on 3-hydroxybutyrate, glucose, fructose, citrate or succinate. However, only 3-hydroxybutyrate apart from P(3HB) induced the secretion of PHA depolymerase. The PHA depolymerase was purified from the culture medium containing 3-hydroxybutyrate at the sole carbon source by hydrophobic column chromatography and gel filtration, and its molecular weight was determined as about 40,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The optimum activity of degrading P(3HB) by the depolymerase was observed at pH 5.5 and 40 degrees C. The enzymatic degradation of microbial copolyesters was studied by the weight loss (erosion) of solution-cast films of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate). 1H-n.m.r. analysis of the water-soluble products after the hydrolysis of P(3HB) film by PHA depolymerase revealed that the main product was the monomer 3-hydroxybutyric acid.

Bacterial Proteins↗
PubMed1993

Kinetics and mechanism of heterogeneous hydrolysis of poly[(R)-3-hydroxybutyrate] film by PHA depolymerases.

The kinetics and mechanism of enzymatic degradation on the surface of poly[(R)-3-hydroxybutyrate] (P[(R)-3HB]) film have been studied using three types of extracellular poly(hydroxyalkanoate) (PHA) depolymerases from Alcaligenes faecalis, Pseudomonas picketti and Comamonas testosteroni. The monomer and dimer of 3-hydroxybutyric acid were produced during the course of the enzymatic degradation of P[(R)-3HB] film, and the rate of production was determined by monitoring the increase in absorbance at 210 nm on a spectrophotometer. The rate of enzymatic degradation increased to a maximum value with the concentration of PHA depolymerase, followed by a gradual decrease. The kinetic data were accounted for in terms of a heterogeneous enzymatic reaction, involving enzymatic degradation on the surface of P[(R)-3HB] film via two steps of adsorption and hydrolysis by a PHA depolymerase with binding and catalytic domains. The kinetic results suggest that the properties of the catalytic domains are very similar among the three PHA depolymerases, but that those of the binding domains are strongly dependent on the type of depolymerase.

Alcaligenes↗
PubMed1993

Effects of heart rate on left ventricular filling dynamics: assessment from simultaneous recordings of pulsed Doppler transmitral flow velocity pattern and haemodynamic variables.

OBJECTIVE: The effects of heart rate on transmitral flow velocity pattern are still controversial. The aim of this study was to examine the relations between the changes in Doppler echocardiographic variables and those in haemodynamic variables in association with altering heart rate. METHODS: Pulsed Doppler transmitral flow velocity pattern and left atrial and left ventricular pressures were simultaneously recorded at various heart rates (from 80 to 120 beats.min-1) in 14 dogs. RESULTS: As heart rate increased, peak late diastolic filling velocity increased, the time-velocity integral of the early diastolic filling wave decreased, and the deceleration time of early diastolic flow shortened without significant changes in mean values of peak early diastolic filling velocity and acceleration time of early diastolic flow. Peak early diastolic filling velocity increased with heart rate, however, in five dogs and decreased in the other nine dogs. The shortening of the time constant of left ventricular isovolumic relaxation was greater in the five dogs in which peak early diastolic filling velocity increased with heart rate than in the other nine dogs. Results of multiple stepwise linear regression analysis showed that the changes in peak early diastolic filling velocity correlated with the changes in the crossover pressure and peak+dP/dt in addition to the time constant, and that diastolic filling period was not selected as an affecting factor. Changes in the other Doppler echocardiographic variables did not correlate solely with changes in heart rate, or diastolic filling period, but correlated in a complex fashion with the combined changes in haemodynamic variables associated with altering heart rate. CONCLUSIONS: Although transmitral flow velocity pattern changes with altering heart rate, this change is not considered to be a direct effect of alteration in heart rate, but an indirect one through the associated haemodynamic changes including left atrial pressure and left ventricular relaxation and contractility.

Animals↗
PubMed1993

Influence of carbonate on sintering of apatites.

Sintering of carbonate apatite, prepared at 100 degrees C and pH 9.0 for 3 days, was studied by thermal analysis, x-ray diffraction, and infrared spectroscopy. The sintering temperature, at which the linear thermal shrinkage of isostatically compacted specimens increased sharply, decreased in proportion to the amount of carbonate initially present in the apatite. For example, specimens with over 8 wt% carbonate could be sintered at a temperature (650 degrees C) which was nearly 400 degrees C lower than that needed for sintering a specimen with no carbonate. Amounts of carbonate lost at the end of sintering, estimated chemically and by infra-red spectroscopy, were approximately equal to sample weight losses estimated thermogravimetrically.

Carbonates↗
PubMed1993

Noninvasive evaluation of total occlusion of infarct-related coronary artery after a first myocardial infarction.

Previous studies have demonstrated that the long-term prognosis after acute myocardial infarction in patients whose infarct-related artery remains occluded is worse than that in those with anterograde flow. To determine how to identify patients with occluded infarct-related arteries noninvasively, 143 consecutive patients after a first myocardial infarction underwent exercise testing and dipyridamole thallium scintigraphy. The incidence of total occlusion was higher in inferior/posterior infarction than in anterior infarction (29/53 vs 28/90; p = 0.005). In patients with inferior/posterior infarction, discriminant analysis revealed a sensitivity of 79%, a specificity of 88% and an accuracy of 83% (p = 0.0005) in identifying those with an occluded infarct-related artery. In patients with anterior infarction, the analysis showed a sensitivity of 68%, a specificity of 85% and an accuracy of 79% (p < 0.0001) in identifying those with an occluded artery. These results indicate that noninvasive study may be useful in the evaluation of total occlusion of the infarct-related coronary artery.

Adult↗
PubMed1993

Cytochemical and immunocytochemical demonstration of acetylcholinesterase of the prenatal rat lower limb.

Acetylcholinesterase (AChE) activities in the prenatal rat lower limb were investigated by both cytochemistry and immunocytochemistry. Results indicate that the epidermal cells show immunoreactions of AChE at a limited stage at prenatal day 15, and mesenchymal cells which are occasionally in contact with the basal lamina or with the adjacent myotubes begin to show AChE activities at prenatal day 17. Such AChE-positive mesenchymal cells, involved in the formation of the muscular tissues, have almost disappeared in the subepidermis by prenatal day 19. This suggests that AChE independent of the neuromuscular system may be involved in the mesenchymal cell differentiation especially in the inductive process during myogenesis.

Acetylcholinesterase↗
PubMed1993

[Noninvasive identification of left main and triple vessel coronary artery disease using dipyridamole thallium scintigraphy].

The diagnostic value of dipyridamole thallium scintigraphy for the noninvasive identification of left main (LM) and triple vessel (TV) coronary artery disease (CAD) was evaluated in 615 consecutive patients with known or suspected CAD. One hundred thirty-nine patients had LM or TVCAD; the remaining 476 patients had limited CAD (double vessel CAD in 112, single vessel CAD in 235, insignificant lesions in 129). Patients with LM or TVCAD, compared to those with limited CAD, had a higher incidence of diffuse slow washout (58 vs 20%, p < 0.0001), extensive fixed defects (21 vs 6%, p < 0.0001) and extensive reversible defects (32 vs 8%, p < 0.0001). During dipyridamole loading, the incidence of chest pain was higher (65 vs 41%, p < 0.0001), and the magnitude of ST depression was greater (0.16 +/- 0.14 vs 0.04 +/- 0.07 mV, p < 0.001) in patients with LM or TVCAD than in those with limited CAD. Stepwise discriminant analysis using scintigraphic imaging achieved a sensitivity of 69%, a specificity of 79%, and an accuracy of 77% for diagnosing patients with LM or TVCAD. After including clinical markers of ischemia during dipyridamole loading, multivariate analysis revealed an improved diagnosis with a sensitivity of 71%, a specificity of 85%, and an accuracy of 82%. These results clearly show the usefulness of scintigraphic imaging as well as the significance of careful assessment of clinical markers of ischemia during dipyridamole loading for the noninvasive identification of LM and TVCAD.

Adult↗
PubMed1993

[A case of intralobar pulmonary sequestration associated with an accessory diaphragm].

We report one operated case (a 71-year-old female) of intralobar pulmonary sequestration (Pryce's type 1) associated with an accessory diaphragm. The patient had hemoptysis for 5 years. Lateral chest X-ray showed an oblique line attaching to the central portion of the right diaphragm. Selective angiography and ultrasonography showed an aberrant vessel originating from the abdominal aorta. At the time of operation, the pleural cavity was divided into two compartments by a fibrous membrane. The bronchus of the lower compartment and the pulmonary veins ran through a hole in the accessory diaphragm. The aberrant artery flowed into the parts of lung in the upper and lower compartments.

Abnormalities, Multiple↗
PubMed1993

[A case of acute eosinophilic pneumonia with Kerley's lines (A and B) on chest X-ray].

A 18-year-old woman presented to our hospital complaining of an acute onset of progressive dyspnea with nonproductive cough and high fever. The patient was in her usual good health until the previous day, when she started to develop symptoms 8 hours after taking aspirin for a headache. The chest roentgenogram revealed Kerley's lines (A and B), perivascular cuffing and hilar haze with bilateral pleural effusions. Body temperature was 38 degrees C and PaO2 was 48 torr. Infectious diseases and extrinsic allergic alveolitis were excluded. The lymphocyte stimulating test was negative for aspirin. Acute eosinophilic pneumonia was strongly suggested by bronchoalveolar lavage showing a marked increase in eosinophils without peripheral eosinophilia. By the seventh hospital day all clinical and radiographic signs were improved without steroid therapy. Most cases of acute eosinophilic pneumonia reported previously showed diffuse infiltrative shadows on the chest roentgenogram. The present case had interesting radiographic findings which suggested interstitial pulmonary edema.

Acute Disease↗