Search PubMed⌕ Search

Biomedical subjects

S Miki

Publications and source records attributed to S Miki.

At least 145 records · Page 8Linked to original sources
PubMed1991

Dependence of Doppler echocardiographic transmitral early peak velocity on left ventricular systolic function in coronary artery disease.

The influence of systolic function on pulsed Doppler echocardiographic transmitral flow velocity patterns was assessed before and after postextrasystolic (PES) potentiation in 12 normal subjects (control group) and in 25 patients with previous healed myocardial infarction (MI) group. Simultaneous high-fidelity left ventricular pressure measurements were performed in all patients. A programmed single-coupled right ventricular extrasystole was induced during echocardiographic and subsequent cineangiocardiographic recordings. Adequate angiograms for volumetric analysis in both baseline and PES beats were obtained in 23 patients (7 in the control group and 16 in the MI group). PES potentiation of contraction was more pronounced in the MI group than in the control group. PES changes in ejection fraction, stroke volume and end-systolic volume were significantly greater in the MI group than in the control group (11 vs 5%, p less than 0.005; 15 vs 5 ml/m2, p less than 0.005; and -13 vs -4 ml/m2, p less than 0.01, respectively). In contrast, PES potentiation prolonged the time constants of left ventricular pressure decline derived from exponential curve fits with a zero (Tw) and non-zero (Tb) asymptote pressure in the MI group to the same extent as in the control group (4 vs 5 ms, difference not significant [NS], and 9 vs 11 ms, NS, respectively). In the PES beat, peak E velocity remained unaltered (48 vs 49 cm/s, NS) in the control group, whereas it increased significantly (p less than 0.0001) from 47 to 51 cm/s in the MI group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Suicide process of renal cell carcinoma cells encountering mumps virus.

Renal cell carcinoma cells produced the substance(s) which killed them (suicide factor(s)) after co-culture with mumps virus. The suicide factor(s) were heat-sensitive and were degraded with trypsin. Furthermore, actinomycin D inhibited the production of the substance(s) by cancer cells. Considering these facts, the substance(s) were thought to be protein(s) derived from de novo synthesis in cancer cells. It was demonstrated that renal cell carcinoma cells proliferated with the autocrine loop of interleukin-6 (IL-6). Mumps virus almost completely inhibited the IL-6 production in several hours. Because of these two facts, the suicide process might be initiated in renal cell carcinoma cells after encountering mumps virus, i.e. inhibition of the autocrine growth loop of IL-6 followed by the induction of an autocrine killing loop of unknown substance(s).

Carcinoma, Renal Cell↗
PubMed1991

Bidirectional cavopulmonary anastomosis using vertical vein for right isomerism, pulmonary atresia, and TAPVR.

An 8-year-old girl who was diagnosed as having right atrial isomerism, pulmonary atresia, butterfly-shaped juxtaductal pulmonary arterial stenosis, total anomalous pulmonary venous return of the supracardiac type, regurgitant common atrioventricular valve, and univentricular heart of the right ventricular type underwent bilateral, bidirectional cavopulmonary anastomosis using a vertical vein and anastomosis between the common pulmonary venous trunk and atrium. The surgical procedure in this patient is described.

Anastomosis, Surgical↗
PubMed1991

Propranolol for intractable hemolysis after open heart operation.

Postoperative intravascular hemolysis occurring in 2 patients was alleviated by propranolol. One patient underwent mitral valve replacement and had development of intractable hemolysis due to a paravalvular leak. The other patient underwent ventricular septal defect closure and had hemolysis caused by the Dacron patch. Both patients were given oral propranolol, and the degree of hemolysis decreased substantially. Although the exact mechanism of the propranolol effect on mechanical intravascular hemolysis is unclear, propranolol is thought to reduce the shearing stress between erythrocytes and the foreign material by slowing the velocity of the circulation.

Anemia, Hemolytic↗
PubMed1991

Doppler echocardiographic transmitral peak early velocity does not directly reflect hemodynamic changes in humans: importance of normalization to mitral stroke volume.

Doppler echocardiographic transmitral peak early velocity normalized to the time-velocity integral during diastole is equivalent to volumetric peak filling rate normalized to stroke volume. To compare the pathophysiologic validity of normalized and nonnormalized peak early flow velocity, pulsed Doppler echocardiography with simultaneous high fidelity left ventricular pressure measurements was performed in 52 patients with coronary artery disease. Left ventricular loading conditions were changed by intravenous administration of norepinephrine in 15 patients and synthetic atrial natriuretic polypeptide in 15 others. Norepinephrine increased nonnormalized and normalized peak early flow velocities in association with significantly elevated end-diastolic, peak systolic and mitral valve opening pressures and decelerated the time constant of left ventricular isovolumetric pressure decline. Atrial natriuretic polypeptide did not change either nonnormalized or normalized peak early flow velocity, despite significant reductions in end-diastolic, peak systolic and mitral valve opening pressure and an accelerated time constant. Normalized peak early flow velocity showed the highest univariate correlation with long-term change in mitral valve opening pressure (n = 52, r = 0.67, p less than 0.0001). It provided a modest univariate correlation (n = 30, r = 0.74, p less than 0.0001) with immediate change in mitral valve opening pressure during norepinephrine infusion, whereas this correlation was lower (n = 30, r = 0.57, p less than 0.001) during polypeptide infusion. However, multivariate regression analysis relating normalized peak velocity with long- and short-term changes in end-diastolic, peak systolic and mitral valve opening pressures, time constant and constant of left ventricular chamber stiffness improved the correlation coefficients (r = 0.80 to 0.85, all p less than 0.0001). In contrast, neither univariate nor multivariate correlations of nonnormalized velocity with long- and short-term changes in these hemodynamic variables were satisfactory. Thus, nonnormalized peak early flow velocity does not directly reflect underlying hemodynamic changes in humans. Normalization to mitral stroke volume clarifies the dependence of peak early flow velocity on the determinants of early diastolic filling. When left ventricular early diastolic filling is evaluated by Doppler echocardiography, normalized peak early flow velocity should be taken into consideration.

Atrial Natriuretic Factor↗
PubMed1991

Noninvasive detection and monitoring of renal arteriovenous fistula by color Doppler.

The diagnosis of a renal arteriovenous fistula is usually confirmed by angiography. Described is the utilization of color Doppler ultrasound to monitor a renal arteriovenous fistula before and after treatment by transcatheter steel coil embolization in a 63-year-old woman. Using color Doppler, the arteriovenous fistula with an aneurysmal lesion was clearly visualized. A pulsed-wave Doppler analysis showed increased flow velocity and decreased pulsatility in the supplying artery. After successful transcatheter occlusion of the fistula, these findings disappeared. The Doppler ultrasound technique is likely to be useful to detect and monitor a renal arteriovenous fistula noninvasively, simply, and quickly.

Arteriovenous Fistula↗
PubMed1991

Total and split renal function assessed by ultrasound Doppler techniques.

We evaluated total and split renal functions from the pattern for renal arterial blood flow detected by ultrasound Doppler in healthy subjects and patients with varying degrees of renal function and disorders other than renovascular hypertension or severe aortic valvular disease. A renal-time pulsed ultrasonic echo-Doppler device at 2.5 MHz was used with a translumbar approach. The ratio of peak diastolic (D) to systolic (S) velocity correlated well with both p-aminohippurate clearance and creatinine clearance. Acceleration time was correlated with the clearance of neither compound. To evaluate the clinical usefulness of ultrasound Doppler in the assessment of split renal function, we compared the D/S ratio with the renal function obtained by radionuclide methods for individuals. The split renal glomerular filtration rate, calculated by a method which makes use of the early renal uptake of 99mTc-diethylenetriam-inepentaacetic acid, correlated well with the D/S ratio. These results indicate that the ultrasonic measurement of renal arterial blood flow by the pulsed Doppler method should be useful for assessment of total and split renal functions.

Adolescent↗
PubMed1991

Purification and characterization of a novel lyase from Cellulomonas sp. that degrades Fusarium and Gibberella acidic polysaccharides.

A Cellulomonas sp. isolated from soil produced a novel lyase that degraded the acidic polysaccharide of Fusarium sp. M7-1 with the formation of mannose and O-beta-D-mannopyranosyl-(1----2)-D-mannose. DEAE-Toyopearl 650M column chromatography showed three lyase activity peaks (fractions I, II, and III). The major fraction was purified to homogeneity by polyacrylamide gel electrophoresis analysis, and its molecular weight was 74,000. The optimum pH was 6.5 to 8.0 and the stable pH range was 6.0 to 8.0. The purified enzyme did not degrade glucuronic or galacturonic acid-containing polysaccharides such as chondroitin, hyaluronic acid, pectin, or pectic acid. However, the purified enzyme specifically degraded various Fusarium and Gibberella acidic polysaccharides, and unsaturated sugars were produced with the release of mannose and O-beta-D-mannopyranosyl-(1----2)-D-mannose. These results suggest that the acidic polysaccharides derived from Fusarium and Gibberella have similar structures.

Bacterial Proteins↗
PubMed1991

Pharmacokinetics and efficacy of carvedilol in chronic hemodialysis patients with hypertension.

The efficacy, safety, and pharmacokinetics of carvedilol were investigated in an open trial performed on six patients with hypertension and chronic renal failure requiring hemodialysis. The plasma level of unchanged carvedilol after a single dose of 10 mg reached a peak 1-5 h after administration both on days with and without hemodialysis. The drug was gradually metabolized thereafter and had almost disappeared from the plasma after 24 h. Blood pressure was lowered by carvedilol both on days with and without hemodialysis. No carvedilol passed through the dialysis membrane. During the 4-week administration period of carvedilol at 10 mg/day, assessment of plasma samples taken just prior to early morning administration demonstrated no drug accumulation. Blood pressure was well controlled during the administration period. Tolerance to the antihypertensive effect was not observed. Heart rate was not significantly changed at any time. There were no side effects in any of the patients during the trial, and laboratory parameters remained unchanged. These results indicate that carvedilol is a safe and effective antihypertensive agent for use in patients on chronic hemodialysis.

Adrenergic beta-Antagonists↗
PubMed1991

[Tricuspid endocarditis related to a residual ventricular septal defect: a case report of successful tricuspid valvuloplasty].

A 5-year-old girl presented infected tricuspid valve related to a residual ventricular septal defect. Antibiotic therapy produced a satisfactory initial improvement. However, subsequent deterioration with uncontrolled infection, in spite of alterations of the antibiotic regime, necessitated surgical intervention. Because the lesion was localized to the anterior leaflet of the tricuspid valve, partial excision of this leaflet and patch was undergone with a sustained clinical improvement with minimum residual valvular incompetence. This experience supports the concept that tricuspid valvuloplasty is the method of choice in the treatment of patient with regional right-sided infective endocarditis.

Child, Preschool↗
PubMed1991

[A technique for distal anastomosis in replacement of the ascending aorta and aortic valve with a composite graft: application of an open aortic anastomosis under retrograde cerebral perfusion and deep hypothermic systemic circulatory arrest].

Between 1987 to 1990, six patients underwent replacement of the ascending aorta and aortic valve with a composite graft which was not wrapped with aneurysmal aortic wall; annuloaortic ectasia in 4, aortitis with acute onset of aortic regurgitation in 1, and acute aortic dissection with aortic regurgitation in 1. In 2 patients, "open aortic anastomosis" under deep hypothermic systemic circulatory arrest and retrograde cerebral perfusion was utilized for distal anastomosis of the graft to the resected aortic arch. Three patients required no transfusion. One patient with annuloaortic ectasia and severely dilated left ventricle died from ventricular fibrillation in ICU. One patient with aortitis died from stroke due to occlusion of bilateral carotid arteries 3 years postoperatively. The other 4 patients are alive and favorable. It is our belief that this technique still maintains simplicity and facilitates the secured anastomosis and minimized bleeding.

Adolescent↗
PubMed1991

[Left atrial myxoma associated with ruptured chordae tendineae].

A rare case of left atrial myxoma associated with ruptured chordae tendineae is presented. The patient was 70-year-old woman, and was diagnosed to have a left atrial myxoma. The myxoma was extirpated together with the atrial septum from which tumor developed. After removal of the myxoma, a ruptured strut chordae tendineae of anterior leaflet was also detected and resutured to the original papillary muscle. The cause of the torn chordae is presumed to be so-called "wrecking ball effect", and to be myxomatous degeneration of the valve.

Aged↗
PubMed1991

[Report of a case with a delayed hemolytic transfusion reaction after open heart surgery].

A case of delayed hemolytic transfusion reaction (DHTR) caused by blood transfusions after open heart surgery was reported in a 61-year-old woman. She had undergone mitral annuloplasty 8 years before. She underwent the 2nd mitral and tricuspid annuloplasty for recurrent mitral and tricuspid regurgitation in 1988. After the reoperation, she developed severe hemolytic anemia with fever. The anti-Jka antibody was detected in her serum by the blood antibody screening test. She was diagnosed to have a DHTR. She was treated conservatively and recovered.

Anemia, Hemolytic↗
PubMed1991

[Endogenous uveitis in disseminated intravascular coagulation induced by endotoxin].

A study was made of endogenous uveitis in experimental disseminated intravascular coagulation (DIC) in rabbits. Endotoxin was injected intravenously twice with a 24-hour interval. The time courses of the following were examined: 1) aqueous flare using a laser flare-cell meter 2) the number of leukocytes in the peripheral blood 3) the tumor necrosis factor (TNF) activity in the serum and 4) histopathological changes in the eye, lung, liver and kidney. Aqueous flare increased at 1 hour and was maximal at 6 hours, accompanied by a rapid increase in TNF activity at 1 hour following the first endotoxin administration. The number of leukocytes decreased to 963 +/- 266 cells/mm3 at 1.5 hours with subsequent leukocytosis within 12 hours. After the second injection of endotoxin, the aqueous flare peaked in 30 minutes and was twice as high as the first peak. Leukocyte number and TNF activity showed the same behavior. However, TNF activity was 20% that of the first peak. Histopathological examination indicated fibrin formation in the small vessels of systemic organs within 3 hours following the second administration of endotoxin. Endotoxin induced uveitis was induced in experimental DIC, and leukocytes and TNF activity may thus perform important roles.

Animals↗
PubMed1991

[Effect of azosemide and furosemide on body fluid distribution and vasoactive hormones].

We examined the diuretic action of orally administered azosemide (AZ: 60 mg) and furosemide (FM: 40 mg) and their effects on body fluid distribution and circulatory vasoactive hormones in normal male volunteers. Urine volume and urinary sodium excretion were increased, peaking during 0 to 2 hours in FM and 2 to 4 hours in AZ in response to administration of both diuretics. The cumulative urine volume and urinary sodium excretion for 8 hours showed no significant difference between AZ and FM. Total body water (TBW) was measured by the dynamic distribution of deuterium oxide and a percentage change in circulating plasma volume (ICG ratio) was determined by using indocyanine green. The decrease in TBW and ICG ratio was detected in proportion to the increase in urine volume after administration of AZ and FM. Plasma renin activity (PRA) and plasma concentration of aldosterone (PAC), angiotensin II (ANG II) and arginine vasopressin (AVP) were elevated in response to the reduction in ICG ratio by both diuretics. The responses of PRA, PAC and ANG II to AZ were delayed about 2 hours as compared with those of FM. The increase in AVP with FM was significantly greater than that with AZ detected 2 hours after administration. The elevation of AVP in AZ was delayed and blunted compared with FM. These data indicate that the difference in diuretic property of AZ and FM may induce different stimulation to the secretion of vasoactive hormones through the changes in body fluid distribution and these hormones might modify the anti-edematic effect of AZ and FM.

Administration, Oral↗
PubMed1990

A synthetic peptide corresponding to residues 137 to 157 of p60v-src inhibits tyrosine-specific protein kinases.

A 21-residue synthetic peptide corresponding to a part of the noncatalytic domain of p60v-src (residues 137 to 157) was found to inhibit the tyrosine kinase activity of p60v-src. The half inhibition concentration was ca. 7.5 microM. The peptide (peptide A) did not compete with substrate proteins or ATP. Peptide A also inhibited the autophosphorylation of epidermal growth factor receptor/kinase and the tyrosine-specific protein phosphorylation in the acetylcholine receptor-rich membranes isolated from electroplax of Narke japonica. However, serine/threonine-specific protein kinases such as cAMP-dependent and cGMP-dependent protein kinases were not inhibited by peptide A.

Amino Acid Sequence↗
PubMed1990

Conformation and immunogenicity of engineered repeating segment of the circumsporozoite surface protein of Plasmodium falciparum.

Peptide vaccines based on units of the immunodominant tetrapeptide repeats, Asn-Ala-Asn-Pro and Asn-Val-Asp-Pro, of the circumsporozoite surface protein of the parasite Plasmodium falciparum are presently being developed as potential malaria vaccines. The N-terminal fusion of a hydrophobic protein to units of the tetrapeptide repeat affected the immunogenicity and conformational stability of the peptide, and also induced a secondary structure in the peptide. Peptide antigenicity, as well as conformational stability, was significantly increased.

Amino Acid Sequence↗