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Biomedical subjects

H Shintani

Publications and source records attributed to H Shintani.

At least 73 records · Page 4Linked to original sources
PubMed1992

Involvement of arachidonate cyclooxygenase products in bronchial hyperresponsiveness induced by subthreshold concentration of aerosolized thromboxane A2 analogue (STA2) in guinea pigs.

Effects of a thromboxane synthetase inhibitor (OKY-046) and a cyclooxygenase inhibitor (indomethacin) on bronchial hyperresponsiveness induced by subthreshold concentration of aerosolized thromboxane A2 analogue (STA2) were investigated in anesthetized, artificially ventilated guinea pigs in order to examine the role of the cyclooxygenase pathway in bronchial hyperresponsiveness. Pretreatment with aerosolized OKY-046 significantly inhibited the bronchial hyperresponsiveness to histamine, but pretreatment with intravenous indomethacin showed a tendency to potentiate bronchial hyperresponsiveness. These results suggest that subthreshold concentration of thromboxane A2 contributes to bronchial hyperresponsiveness through activating the cyclooxygenase pathway including thromboxane A2 synthesis, and that the released cyclooxygenase products have an inhibitory effect on the bronchial hyperresponsiveness in guinea pigs.

Aerosols↗
PubMed1992

Global left ventricular performance and regional systolic function after suture annuloplasty for chronic mitral regurgitation.

BACKGROUND: In surgery for chronic mitral regurgitation, the mitral subvalvular apparatus, including annulus, may play an important role in preserving left ventricular (LV) performance. The suture annuloplasty for mitral regurgitation allows annular contraction of the mitral valve. The potential effects of suture annuloplasty on the postoperative LV performance have not been fully defined. METHODS AND RESULTS: Global and regional LV function in 12 patients with suture annuloplasty were compared with 12 patients with conventional mitral valve replacement (MVR). Cineangiography and echocardiography were obtained before and 10.8 months after surgery. End-diastolic volume index and end-systolic volume index decreased significantly in both groups after surgery (p < 0.01). Ejection fraction remained unchanged in the suture annuloplasty group, whereas it decreased significantly in the MVR group after surgery (p < 0.01). There was a significant inverse relation between ejection fraction and end-systolic wall stress in the two groups after surgery (suture annuloplasty group, r = -0.69, p = 0.01; MVR group, r = -0.60, p = 0.04). The intercept on the y axis was significantly (p < 0.005) higher in the suture annuloplasty group than in the MVR group. In the suture annuloplasty group, cross-sectional area ejection fraction at the mitral valve level and at the papillary muscle level by LV two-dimensional echocardiography remained unchanged after surgery. In the MVR group, they decreased significantly after surgery (p < 0.01). There was a significant correlation between the cross-sectional area ejection fraction and the global ejection fraction at both levels after surgery. Therefore, the improvement of the regional wall motion can be attributed to the improvement of the global LV performance after suture annuloplasty. CONCLUSIONS: These data suggest that suture annuloplasty can provide more desirable postoperative LV systolic performance than conventional MVR by preserving both the contraction of the mitral annulus and the mitral valvular-ventricular interaction.

Echocardiography↗
PubMed1992

[The long-term prognosis of coronary artery bypass surgery--the influence of preoperative left ventricular volume on the prognosis of cardiac death].

We have assessed the long-term prognosis about cardiac death of isolated coronary artery bypass surgery from 1972 to 1988 in 361 consecutive patients. The duration of follow-up were from 0.4 years to 14.6 (mean 5.7) years. Of the 361 study patients, the operative morality was 4.7% (17 patients) and 29 patients (8.0%) died during follow-up, 11 (3.0%) of which were from cardiac causes. Actuarial survival rate was 85.2% at 10 years after surgery. The 10 year-survival rate was similar for patients with single, double, triple vessel disease, and left main trunk disease (94.5%, 83.7%, 75.1% and 89.1%, respectively). For patients with and without old myocardial infarction, the 10 year-survival rate was significantly different (75.4% and 93.3%, respectively) (p less than 0.005). In order to detect which factors of preoperative cardiac function among cardiac index, LV end-diastolic pressure, LV end-diastolic volume index, LV end-systolic volume index, and LV ejection fraction influenced the long-term prognosis, multivariant regression analysis was performed. Only LV end-systolic volume index was a significant factor, and the discriminative point was 50 ml/m2. For patients with LV end-systolic volume index less than 50 ml/m2 and greater than or equal to 50 ml/m2, the 10 year-survival rate was significantly different (88.3% and 32.9%, respectively) (p less than 0.005). In conclusion, the most significant factor influencing longterm prognosis after coronary artery bypass surgery was left ventricular end-systolic volume, indicating the importance of preventing preoperative dilatation of left ventricle.

Actuarial Analysis↗
PubMed1992

[Analysis of bronchoalveolar lavage fluid in patients before and after bone marrow transplantation].

We analysed BALF cell findings in 9 patients (group A: 5 patients without lung disease after bone marrow transplantation (BMT), group B: 4 patients with lung disease after BMT) before and after BMT. Before BMT, BALF cell findings in group A were almost normal, whereas a relative increase of lymphocytes was seen in group B. Although total cell counts and cell composition in group A changed little after BMT, CD4/CD8 ratios in BALF lymphocytes decreased. In contrast, a relative increase of lymphocytes and neutrophils was seen in group B and there was variation of CD4/CD8 ratios in BALF lymphocytes after BMT. We there studied the BALF lymphocytes of 3 patients in group A and 4 patients in group B after BMT by means of 2-color analysis. Among CD4+ cell populations, CDw 29+ cells were decreased in both groups after BMT. A relative increase of BALF-CD4+ HLA-DR+ cells and CD8+ HLA-DR+ cells was seen in group A, but was not seen in group B. These findings suggest that there is abnormality of local immunity in the lung after BMT.

Adult↗
PubMed1991

Formation of 4,4'-methylenedianiline in polyurethane potting materials by either gamma-ray or autoclave sterilization.

In this experiment, we found that a potential carcinogen, 4,4'-methylenedianiline (MDA), was produced from gamma-ray irradiated potting materials, medical thermosetting polyurethane (PU). gamma-Ray irradiated PUs were immersed in either methanol or in equine serum. The time course of MDA leached from the potting materials and other variables were compared. A significant relationship was noted between the amount extracted and the rigidity of the potting material. The accumulated amount of extracted MDA (a few ppm in the original sample) increased with increasing irradiation dose by a second-order equation. One sample indicated reduced MDA elution after irradiation in the early stage. MDA extraction with serum was 82-87% that with methanol. In one case, MDA leaching into serum in the early stage was higher than that into methanol. Autoclave sterilization did not promote MDA formation, thus indicating that autoclaving would be preferable.

Aniline Compounds↗
PubMed1991

Evaluation of a new finger-type intraoperative epicardial echocardiographic probe for infants and small children.

A new finger-type epicardial echocardiographic probe was evaluated in 26 children with complex cardiac anomalies during open heart surgery. The probe is a small 3.75 MHz phased array transducer for 2-dimensional echo and color Doppler imaging. The tip is slightly angled to facilitate the apical approach through a median sternotomy. The patients included 4 neonates and 8 infants, and the major cardiac lesions were complete atrioventricular (AV) canal, transposition of the great arteries, double outlet right ventricle, and others. The intraoperative study was possible in most of the patients facilitating various approaches for the assessment of left-sided AV valve function, left ventricular outflow obstruction, residual shunt and intraatrial anatomy. Four patients received subsequent operative procedures after the assessment. This transducer appears to be useful in the intraoperative study during surgery for complex cardiac anomalies in neonates and small infants.

Child↗
PubMed1991

Cutting effectiveness and wear of carbide burs on eight machinable ceramics and bovine dentin.

As a first approach in evaluating the feasibility of industrial machinable ceramics in dentistry, we performed weight-load-cutting tests on eight machinable ceramics and bovine dentin, using #1557 carbide burs driven by an air-turbine handpiece. While the transverse load applied to the bur was cyclically varied between 20 and 80 g, we measured the cutting speed (i.e., the steady-state handpiece speed during cutting) and the cutting volume. The greater the applied load, the more the cutting speed decreased and the cutting volume increased. The degree of this trend, however, differed among the workpieces. When dentin and mica-based glass ceramics were being cut, the cutting speed was moderately reduced, the cutting effectiveness of the bur remained high, and the wear of the bur was small. When other ceramics--such as AIN-based, Si3N4-based, and CaO.SiO2-based ceramics--were being cut, however, the cutting speed was less diminished, and the cutting efficiency of the bur was smaller and decreased rapidly, along with extensive wear of the bur. We speculate that mica-based glass ceramics could be used as the substitute for dentin in the pre-clinical cutting exercise, and that another potential use of machinable ceramics examined might be in the production of future machined dental prostheses.

Animals↗
PubMed1991

Residual monomers (TEGDMA and Bis-GMA) of a set visible-light-cured dental composite resin when immersed in water.

Rods of a visible-light-cured dental composite resin were photo-polymerized and immersed in water at 37 degrees C for 7 days. The residual monomers (TEGDMA and Bis-GMA) trapped in the set composite and those eluted into water were analysed by gas-liquid chromatography. It became evident that minor amounts of the residual monomers dissolved in water, but that most residual monomers remained in the set composite. Extension of the irradiation period contributed to the significant reduction in the residual monomer level and its elution into water.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1991

Effects of phosphoric acid and tannic acid on dentine collagen.

We examined the effects of phosphoric acid, the most common enamel etchant in composite resin therapy, on dentine collagen. Dentine collagen pretreated with 7M phosphoric acid was shown to be more susceptible to trypsin digestion than untreated collagen. This susceptibility increased with increasing duration of exposure to the acid. The results indicate that phosphoric acid induces a conformational change in dentine collagen (denaturation or perturbation) similar to that observed with 0.39 M HCl, which has a similar pH value (0.65). However, phosphoric acid-pretreated dentine collagen, when treated with tannic acid for 2 h, became as resistant to tryptic digestion as intact dentine collagen. The present results suggest that tannic acid may work as a dentine conditioner in composite resin therapy, in view of the fact that phosphoric acid etchant is applied, either deliberately or inadvertently, to dentine, and would thus induce denaturation or perturbation of collagen.

Animals↗
PubMed1991

Streptococcal adherence to uncoated and saliva-coated restoratives.

The adherence of Streptococcus sanguis and S. mutans to seven restoratives in the presence and absence of an artificial salivary pellicle has been investigated. The physiochemical surface characteristics of the bacteria and of the restoratives were also measured, together with the effect of salivary coating of restoratives. Zeta potential of uncoated restoratives showed a positive correlation with the number of adherent S. mutans cells and S. sanguis cells. S. sanguis showed a positive correlation with the hydrophobicity of uncoated restoratives. The surface hydrophobicity was decreased upon saliva coating, whereas the zeta potential was slightly increased. The contact angles or zeta potentials of saliva-coated restoratives were positively correlated with those of uncoated restoratives. The number of adherent cells of both S. sanguis and S. mutans to saliva-coated restoratives were decreased after the coating. Zeta potential of saliva-coated restoratives showed a positive correlation with the numbers of adherent S. mutans cells, suggesting that non-specific electrostatic interactions have an important role in the adherence of this species.

Bacterial Adhesion↗
PubMed1991

[Inhibitory effects of rhIL-1 beta pretreatment on bleomycin-induced pneumonitis in mice].

We studied the effects of recombinant human interleukin-1 beta (rhIL-1 beta) pretreatment on bleomycin (BLM)-induced pneumonitis in mice. Lung injury was dose-dependently induced by BLM (50 mg/kg, 100 mg/kg, 150 mg/kg i.v.). The mice were pretreated with IL-1 (1 microgram/mouse i.p.) at 0.5, 6, 12 or 24 hours before the administration of BLM. Wet lung weight, lung weight-to-body weight ratio and bronchoalveolar lavage cell findings were analyzed with respect to time, and lung specimens on day 28 after administration of BLM were histopathologically examined. When mice were pretreated with IL-1 at 0.5 hr or 6 hr before the administration of BLM, changes in all the parameters were significantly suppressed. The results indicate that IL-1 pretreatment protects mice from BLM-induced pneumonitis and its effects are time-dependent.

Animals↗
PubMed1991

Hepatic venous oxygen saturation monitoring in patients with assisted circulation for severe cardiac failure.

In order to assess the adequacy of hepatic perfusion, hepatic venous oxygen saturation (ShvO2) was monitored in five patients undergoing mechanical circulatory support. Two patients were with intra-aortic balloon pumping (IABP), one was with a left ventricular assist device (LVAD), and two were with biventricular assist devices (BVAD). The mean ShvO2 values during assistance in each patient ranged from 27 to 84%. One patient with IABP showed persistently low ShvO2 (less than 30%) in spite of higher mixed venous oxygen saturation (SvO2) and subsequently developed hepatic dysfunction and multiple organ failure. In another patient, ShvO2 was 22% on average during LVAD, but increased to greater than 50% after adding a right ventricular assist device (RVAD). Of 3 patients with persistently high ShvO2 (44-80%, on average), only one developed hepatic failure--probably from prior severe shock--and the other two did not develop hepatic failure. There was a significant negative correlation between ShvO2 and splanchnic excess lactate, the parameter of anaerobic metabolism in the splanchnic area. In contrast, there was no correlation between simultaneously measured ShvO2 and SvO2 values when analyzed in a range of SvO2 below 70%. ShvO2 monitoring may be useful for evaluation of hepatic perfusion status in the management of critical patients, requiring assisted circulation.

Heart Failure↗
PubMed1991

[Primary megaureter which showed aplasia of the muscle bundles on all dilated portions: a case report].

A case of primary megaureter in a 59-year-old man which might shed light on the etiology and pathology is described. Intravenous urography and the computed tomography showed a left marked hydro-nephro-ureter which compressed the bladder and right ureter. In the left ureter, dilated portions stretched beyond dilated portions; that is, five non-dilated portions lay among four dilated portions. On histological examination of this specimen, all dilated portions showed aplasia of muscle in which muscle bundles were not observed, while all non-dilated portions including ureterovesical junction showed normal muscle layers. A case presentation and brief review of the literature were made.

Dilatation, Pathologic↗
PubMed1991

[Three cases of minocycline-induced pneumonitis].

All three patients complained of cough, fever and dyspnea. Their chest X-ray films revealed interstitial changes such as Kerley B lines. The results of lymphocyte stimulation tests were all negative for Minocycline (MINO), whereas the provocation tests were all positive in three cases. The onsets of symptoms appeared 7, 12 and 9 hours after administration of MINO respectively, which suggested type III allergy in terms of the latency period. In cases No. 1 and No. 3, lung tissue specimens obtained by transbronchial biopsy showed findings of mild acute eosinophilic pneumonia. The bronchoalveolar lavage fluid of case No. 3 showed eosinophilia. On diagnosing MINO-induced pneumonitis, the lymphocyte stimulation test is not always beneficial, whereas the provocation test is supposed to be a safe and sure method.

Adult↗
PubMed1991

[A case of uretero-vaginal fistula with ureteral foreign body stone originated from the suture thread].

A 32-year-old female was admitted to our hospital with the chief complaint of vaginal discharge of urine. She had undergone radical hysterectomy due to uterine cancer at another hospital by a gynecologic surgeon 5 years earlier. X-ray examination showed a stone-like shadow at the left ureter without hydronephrosis. She was diagnosed with ureterovaginal fistula with the left ureteral stone. Left ureterolithotomy and ureterovesiconeostomy was performed. The stone revealed a foreign body stone originating from the silk worm-gut which had penetrated accidentally the ureter when the vaginal wall was sutured at the previous surgery. Including our case, 15 cases of foreign body stones in the upper urinary tract were found in the Japanese literature and none of them were associated with ureterovaginal fistula.

Adult↗
PubMed1991

Long-term survival and complications after composite graft replacement for ascending aortic aneurysm associated with aortic regurgitation.

The Bentall operation was performed in 44 patients between March 1972 and December 1988. Twenty patients had stigmata of Marfan's syndrome, and 15 had aortic dissection. All showed annuloaortic ectasia. Follow-up ranged from 1 to 16 years (mean, 5.8 years). There were six early deaths (14%) and seven late deaths (16%), with actuarial survival at 10 years of 65 +/- 8%. The late deaths were mostly related to aneurysms occurring in the remainder of the aorta. No patient has undergone reoperation related to the composite graft, but six patients required seven subsequent operations on the remaining aorta. The actuarial probability of freedom from late death and subsequent operation at 8 years was 64 +/- 9% for the operative survivors, but it was 44 +/- 17% for the patients with aortic dissection and 37 +/- 19% for those with Marfan's syndrome. Postoperative angiography performed 3-168 months (mean, 42 months) postoperatively in 23 nonselective patients demonstrated recurrent true aneurysms at both or one of the coronary ostia (seven), persistent dissection distal to the distal aortic anastomosis (five), pseudoaneurysm at the left coronary ostium (one), pseudoaneurysm due to a small leak at the proximal aortic anastomosis (one), and partial dehiscence of the distal aortic suture line (one). Composite graft replacement carries a potential risk of various late complications. Our data support the concept that earlier detection and aggressive treatment of the late complications occurring in the remainder of the diseased aorta is necessary to improve long-term survival after the Bentall operation.

Actuarial Analysis↗
PubMed1991

A five-year appraisal and hemodynamic evaluation of the Björk-Shiley Monostrut valve.

Two hundred forty-four Björk-Shiley Monostrut valves were implanted in 225 consecutive patients from October 1983 to December 1988. Aortic valve replacement was performed in 90 patients, mitral valve replacement in 118, and double valve replacement in 16 patients. One patient had tricuspid valve replacement. There were 100 female patients and 125 male patients with a mean age of 54 years (range 2 to 71 years). Present data were completely available for all patients. The cumulative follow-up was 541 patient-years with a mean of 2 years, 5 months. The closing date for follow-up was July 1989, and the closing interval was 2 months. The early mortality rate was 3.1%, and the late mortality rate, 3.1%. The 5-year survival rate was 88% +/- 2.0%: 87% +/- 3.0% for aortic valve replacement, 91% +/- 3.3% for mitral valve replacement, and 75% +/- 9.6% for double valve replacement. The actuarial rates of freedom from thromboembolism at 5 years were 93% +/- 3.2% for aortic, 96% +/- 1.4% for mitral, and 94% +/- 6.1% for double valve replacement. There were no instances of structural valve deterioration. Actuarial rate of freedom from valve-related morbidity and mortality was 86% +/- 2.0% at 5 years: 86% +/- 9.5% for aortic, 87% +/- 3.3% for mitral, and 75% +/- 7.3% for double valve replacement. Effective valve areas (average) of 12 mitral and 12 aortic valve prostheses were calculated at rest and during bicycle exercise: 2.4 cm2 at rest and 2.8 cm2 during exercise in 27 mm aortic valves, 2.4 cm2 at rest and 3.0 cm2 during exercise in 25 mm aortic valves, 2.0 cm2 at rest and 2.4 cm2 during exercise in 27 mm mitral valves, and 2.6 cm2 at rest and 2.5 cm2 during exercise in 29 mm mitral valve. On the basis of our follow-up period of 5 years, we have judged the Björk-Shiley Monostrut valve reliable, with a low incidence of valve-related morbidity and with acceptably satisfactory hemodynamic characteristics at rest and during exercise.

Adolescent↗