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Y Imai

Publications and source records attributed to Y Imai.

At least 649 records · Page 36Linked to original sources
PubMed1994

Influence of primers containing cupric ion on bonding of dentin treated with phosphoric acid.

A primer containing cupric [Cu (II)] ions that promoted the interfacial initiation of polymerization from dentin surfaces was studied. Bovine dentin surfaces were treated with 10% phosphoric acid, then with a Cu primer consisting of aqueous 35% 2-hydroxyethyl methacrylate (HEMA) containing 0.03% cupric salt, and finally bonded with 4-META/MMA-PMMA resin initiated with oxidized tributylborane (TBBO). The use of the Cu primer resulted in a mean bond strength of 12.5 MPa compared with 3.8 MPa without the primer and 6.3 MPa using a 35% HEMA primer without Cu. The Cu primer produced a bond strength of 13.5 MPa even without 4-META in the resin system. Use of the Cu primer should simplify the bonding procedure since enamel and dentin can be etched simultaneously with 10% phosphoric acid.

Acid Etching, Dental↗
PubMed1994

[Releases of bradykinin and substance P by heating hind paw of rat].

Contribution of kallikrein-kinin system to heat-induced substance P (SP) release into the periphery was studied by using plasma kininogens-deficient strain Brown Norway Katholiek (B/N-Ka) and normal strain Brown Norway Kitasato (B/N-Ki) rats. Bradykinin (BK) and SP levels in the sc perfusates of the hind instep were measured by radioimmunoassay. In B/N-Ki rat, immersion of hind paw into hot water (47 degrees C) for 20 min led to an increase of BK (43 +/- s 34 fmol.min-1) and SP (11.1 +/- 9.7 fmol.min-1) in the perfusate, whereas those in B/N-Ka rat (BK 1.3 +/- 1.0 fmol.min-1 (P < 0.01), SP 5.5 +/- 3.5 fmol.min-1 (P < 0.05)) were remarkably less. Heat-induced extravasation (leakage of Evans blue) in B/N-Ka rat was also less than that in B/N-Ki rat (P < 0.05). Results suggest that kallikrein-kinin system is involved in the release of SP into the periphery, ie, BK released into the extravascular space by noxious heat stimulation intervenes in SP release.

Animals↗
PubMed1994

p53 mutations and MDM-2 amplification in renal cell cancers.

Genomic DNA from 53 primary human renal cell tumors was screened for the presence of mutations in the tumor suppressor gene p53, using the polymerase chain reaction and single-strand conformation polymorphism analysis, followed by direct sequencing of DNA. Five cases showed mobility shifts. Sequencing of these samples revealed two cases of nonsense mutations (codons 182, 192), one case of a missense mutation (codon 285), and two cases of silent mutations at codon 213. The frequency of mutations altering the p53 (3/53 = 6%) was low when compared with the reported frequencies (15% to 65%) of allelic loss of 17p (location of p53) in renal cell cancers, suggesting the possible existence of another tumor suppressor gene in the region of the p53 gene, which when mutated is associated with these cancers. All three tumors with p53 mutations were cases with poor prognosis, i.e., highest pathological grade and/or advanced Robson stage. The human equivalent of the murine double-minute-2 was not amplified in the renal cell tumors. In summary, alterations of p53 may be associated with the development of renal cell carcinoma of higher grade and/or stage.

Base Sequence↗
PubMed1994

[Surgical treatment of thrombosed aortic dissection].

We have performed the graft replacement of descending thoracic aorta for 6 patients with aortic dissection having non-opacified false channel on their initial CT and aortography from April 1990 to January 1993. We report the findings obtained from preoperative CT and aortographic findings and from operation with these patients. We also report the microscopic study of aortic wall resected at operation. In all the six patients were found by CT and angiography performed at the admission non-opacified false channel. In one patient, a re-dissection occurred at the mid-descending aorta four weeks later and extended into the abdominal aorta. Intimal tears were found during operation both at distal to the left subclavian artery and at mid-descending aorta in this patient, and microscopically the outer media of aortic wall had been ruptured and the advential scarring were more conspicuous than usual. In the other 5 patients, the local opacification was gradually increased in size during the follow up period. The site of local opacification was at the distal to the left subclavian artery in 3 and at the mid-descending aorta in 2. The operation for these patients revealed the existence of intimal tear at the involved aorta but the false channel had been closed. Microscopically, the involved aorta formed pseudoaneurysm and false channel had been closed with the organized thrombus. From these findings we conclude that surgical treatment should be considered for the aortic dissection when re-dissection occurred or local opacification was increased in size during follow up period, even if initial CT and aortography showed non-opacified false channel.

Aged↗
PubMed1994

[Left ventricular characteristics after Jatene operation for transposition of the great arteries with intact ventricular septum--comparative study of neonatal primary and two stage repairs].

Left ventricular characteristics in late postoperative period after the arterial switch operation (ASO) was evaluated in fifty-nine patients with transposition of the great arteries and intact ventricular septum. They included 22 neonates who underwent a neonatal ASO (Group I) and 37 patients who underwent a two-stage ASO (Group II). Group II was subdivided into two groups according to the presence or absence of aortic regurgitation in the late postoperative period as group IIa (aortic regurgitation [-], 22 patients) and group IIb (aortic regurgitation [+], 15 patients). Age at ASO ranged from 4 to 27 days (average 12.7 days) in the group I, 5 to 43 months (average 12.7 months) in the group IIa, and 4 to 54 months (average 16.3 months) in the group IIb. Postoperative follow-up period ranged from 8 to 68 months (average 25.0 months) in the group I, 12 to 74 months (average 59.0 months) in the group IIa, and 19 to 66 months (average 48.5 months) in the group IIb. Left ventricular end-diastolic volume was significantly smaller in the group I (123 +/- 19% of normal) than the group IIa (146 +/- 38 of normal) and the group IIa (183 +/- 53% of normal). And left ventricular ejection fraction was significantly higher in the group I (67 +/- 5%) than the group IIa (62 +/- 11%) and the group IIb (58 +/- 8%). Left ventricular normalized mass was significantly smaller in the group I (85 +/- 11% of normal) than the group IIa (113 +/- 14% of normal) and the group IIb (130 +/- 9% of normal).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

[P450].

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed1994

[Reoperations of extracardiac valved conduit for congenital cardiac defects].

Fifteen of 223 patients who have had extracardiac conduit repair at the Heart Institute of Japan from January, 1970, to April, 1991, have required conduits replacement because of conduit obstruction or infection. The main causes of obstruction were degeneration of the prosthetic valve and proliferative pseudo-intima in the conduit. The interval between initial conduit repair and conduit replacement was 2.2 to 18.3 years (mean 10.5 +/- 4.4). The average pressure gradient through the conduit decreased from 74.7 +/- 42.0 mmHg preoperatively to 12.3 +/- 7.1 mmHg postoperatively (p < 0.05). There was no early and late death. We concluded that xeno-pericardial roll conduits were superior to others and that conduit replacement procedure following the extracardiac conduit repair was safe and effective.

Adolescent↗
PubMed1994

Mutations of the p53 gene are not detectable in human testicular tumors.

The tumor suppressor gene p53 is the most frequently mutated gene in human cancer. We have used polymerase chain reaction-single-strand conformation polymorphism analysis and sequencing to examine the status of the p53 gene in human testicular cancers of various histologies. We were unable to find in 40 samples and four cell lines any mutations in the regions of this gene (exons 5 through 8) that are usually mutated in other cancers. Northern blot analysis showed expression of this gene in most of the samples analyzed, as well as in four human testicular tumor cell lines. The MDM-2 gene is amplified and overexpressed in sarcomas; it binds and functionally inactivates p53. The 44 testicular tumor samples and cell lines were examined for amplification of MDM-2 by dot-blot analysis; none was found. The proto-oncogene c-kit probably plays an important role in normal testicular development. Mutation of the tyrosine phosphorylation site of a closely related member of this family of tyrosine kinase receptors (c-fms) is associated with cellular transformation and cancer. Codon 936 is the analogous tyrosine of c-kit; using polymerase chain reaction-single-strand conformation polymorphism analyses, we were unable to detect mutations at this site in our 44 testicular cancer samples. We conclude from our studies that mutations in the most conserved region of the p53 gene, as well as at codon 936 of the c-kit gene and amplification of MDM-2, are extremely rare in human testicular cancers.

Base Sequence↗
PubMed1994

Macro-fingerprinting analysis at the chromosomal genomic DNA level of isolates of thermophilic Campylobacter coli and C. jejuni, by pulsed-field gel electrophoresis.

Chromosomal genomic DNA from 25 strains of thermophilic Campylobacter coli and C. jejuni were analysed after pulsed-field gel electrophoresis (PFGE) of restriction fragments generated by SalI and SmaI to evaluate the utility of macro-fingerprinting analysis and to assess the possible subtyping of the isolates. Two rare-cutting restriction enzymes, SalI and SmaI, allowed the subclassification of eight strains of C. coli into six types. SalI facilitated the subclassification of seventeen strains of C. jejuni into thirteen types and SmaI the subclassification of seventeen strains into twelve types. The diversity in the PFGE profiles was demonstrated and, therefore, the two enzymes were found to be potentially useful for detecting variability of PFGE profiles among strains of C. coli and C. jejuni. The two enzymes and PFGE may be useful in molecular epidemiology.

Animals↗
PubMed1994

Pressor effect of recombinant human erythropoietin: results of home blood pressure measurements in hemodialysis patients.

We investigated whether the treatment of anemic hemodialysis patients with a low dose of recombinant human erythropoietin (rHEpo) for a short period would increase the blood pressure (BP). Home BP measurements were used to detect minute increases in BP. Fifty-one anemic patients on maintenance hemodialysis with a hematocrit of 25% or less received rHEpo at the dose of 4500 IU/week by the intravenous route for 8 weeks. Overall, rHEpo did not increase the BP whether measured at home or in the clinic (causal BP). Hemoglobin concentration increased significantly from 7.1 +/- 0.7 to 8.8 +/- 0.7 g/dl. Patients were classified into two groups according to the change in mean (M) home BP induced by rHEpo: a pressor group (delta MBP > or = 5 mmHg, n = 17) and a non-pressor group (delta MBP < 5 mmHg, n = 34). The hemoglobin concentration rose significantly in both groups, but there was no change in casual BP. Home blood pressure measurements showed a gradual and continuous rise in BP in the pressor group, but not in the non-pressor group. Patients administered antihypertensive medications before rHEpo treatment accounted for 88% of the former and 50% of the latter groups. Two patients with malignant nephrosclerosis were included in the pressor group. The findings indicate that rHEpo, even given at a low dose for a short period, elevates the BP, as determined by home BP measurement, but not by casual measurements obtained in the clinic.

Adult↗
PubMed1994

Inflammatory cells in the pseudocapsule of osteosarcoma. A clinicopathologic analysis.

The presence of a "pseudocapsule," composed of an inner compression zone and outer reactive zone, is a frequent finding in the periphery of osteosarcoma. Morphologic and immunohistochemical methods were used to determine the type of inflammatory cell most closely related to the formation of this pseudocapsule. Six and five specimens with and without a compression zone, respectively, were obtained from ten patients with osteosarcoma. The type and number of inflammatory cells in the specimens with and without a compression zone were counted and compared. The reactive zone contained mast cells, macrophages, fibroblasts, and lymphocytes with a predominance of T-cells. Macrophages were significantly increased in number in the specimens with a compression zone. These results strongly suggest that macrophages play a significant role in the formation of the compression zone. The survival rate of the patients with thick encapsulation was markedly better than that of the patients without this feature.

Adolescent↗
PubMed1994

[Advantages of combined antegrade/retrograde GIK cardioplegia for coronary artery bypass surgery].

We evaluated the advantages of combined antegrade and retrograde GIK cardioplegia in 65 patients undergoing CABG. Thirty seven patients were administered antegrade cardioplegia (Group A), whereas 28 patients were administered combined antegrade and retrograde cardioplegia (Group C). Enzyme release and hemodynamic data were obtained before the onset of CPB and at 1, 3, 6, 9, 12 and 24 hours after operation. Both groups were similar in age and incidence of diabetes, previous MI, PTCA, severity of coronary artery disease and emergent operation. In group A, antegrade cardioplegia produced poor anterior septal cooling in 17 patients (45%). To ensure adequate myocardial protection in these cases 9, patients were anastomosed saphenous vein graft first to LAD instead of IMA and perfused cardioplegic solution through the grafts. In group C, although adequate anterior septal cooling also could not be obtained with antegrade cardioplegia in 16 patients (57%), after retrograde cardioplegia, anterior septal temperature fell below 10 degrees C. The use of IMA graft was more practiced in group C. (79% in group C versus 32% in group A, p < 0.05) Enzyme release (CPK-MB, %CPK-MB, LDH) and hemodynamic data (CI, LVSWI, RVSWI, RVEF, RVEDVI) were similar in both group. Furthermore, no significant difference were noted in the incidence of post-operative LOS, PMI and ventricular arrhythmia. We concluded that the use of combined antegrade and retrograde cardioplegia is more effective than antegrade cardioplegia, because of adequate anterior septal cooling, and it will allow patients with severe and extent coronary artery disease to undergo safe IMA grafting.

Aged↗
PubMed1994

Benign stricture of the intrahepatic bile duct with arterial involvement.

The absence of arterial change is one of the definitive findings of benign bile duct stricture. Here we report on a patient with a stricture of the intrahepatic bile duct with arterial involvement. Histological examination of the resected specimen revealed fibrous replacement of arterial media, with no evidence of malignancy.

Bile Duct Diseases↗
PubMed1994

[Hepatobiliary functions in primary biliary cirrhosis--assessment with 99mTc-PMT hepatobiliary scintigraphy].

To define a relationship between the changes of hepatic and gallbladder functions and the pathological progression in patients with primary biliary cirrhosis, we studied 15 patients at various pathologic stages with 99mTc-N-pyridoxyl-5-methyl-tryptophan (PMT) hepatobiliary scintigraphy. In stage I both the hepatic uptake rates and hepatic excretion rates of 99mTc-PMT were not reduced compared with the normal subjects. According to the progress of the pathologic stage, the hepatic uptake rates of 99mTc-PMT were decreased. The hepatic excretion rates were reduced in stages II, III and IV, but they were not related to the progression of the pathologic stage. The hepatic uptake rate is considered to be useful in evaluating the pathological progression in patients with primary biliary cirrhosis. The mean gallbladder ejection fraction in patients with primary biliary cirrhosis (32 +/- 18%) was significantly lower than that of the normal subjects (72 +/- 13%) (p < 0.005). The reduction of the gallbladder ejection fraction was not related to the progress of the pathologic stage. Sluggish emptying of gallbladder may suggest the gallbladder wall lesion in this disease.

Adult↗
PubMed1994

Ventricular function after anatomic repair in patients with atrioventricular discordance.

Since June 1989, 18 patients with atrioventricular discordant anomalies under 15 years of age underwent anatomic correction, or double switch operation, with 2 hospital deaths (11%). Ages ranged from 1 year 4 months to 12 years (mean 7.2 years) and body weights ranged from 7.1 to 32.5 kg (mean 20.1 kg) at operation. Visceral situs was solitus in 12 and inversus in 6. Ventriculoarterial connection was discordant in 4 and double-outlet in 14. All had associated congenital cardiac anomalies consisting of ventricular septal defect in 17, atrial septal defect in 9, pulmonary atresia in 10, pulmonary stenosis in 6, systemic tricuspid regurgitation in 9, mitral regurgitation in 6, bilateral superior venae cavae in 6, patent ductus arteriosus in 6, Wolff-Parkinson-White syndrome in 2, and congenital atrioventricular block in 1. Previous palliation had been performed 19 times in 11 patients including systemic-pulmonary shunts in 10 patients and pulmonary banding in 1 patient. Anatomic correction consisted in the Mustard procedure in 12 or the Senning procedure in 6 at the atrial level and in external conduit repair in 14, arterial switch operations in 3, or direct anastomosis between the pulmonary artery and right ventricle in 1 at the ventriculoarterial level. The arterial switch operation was indicated in patients with a normal pulmonary valve, and external conduit repair was indicated for patients with pulmonic stenosis or atresia. Anatomic right ventricular end-diastolic volume showed significant reduction from 122.2% +/- 46.3% of normal to 78.8% +/- 24.0%, mainly owing to unloading of the ventricle after the operation (p < 0.0003). Right ventricular ejection fraction remained unchanged (56% +/- 8% to 56% +/- 6%). Anatomic left ventricular end-diastolic volume and left ventricular ejection fraction remained unchanged before and after the operation: volume 134.6% +/- 50.0% of normal to 127.3% +/- 32.8% and ejection fraction from 61% +/- 8% to 56% +/- 8%. Cardiac index averaged 3.1 +/- 0.5 L/min per square meter after the operation. The double switch operation is best indicated in patients with atrioventricular discordance associated with systemic tricuspid regurgitation and/or with poor systemic right ventricular function.

Cardiac Output↗
PubMed1994

[The youngest case of isolated interruption of the aortic arch without associated cardiac anomalies].

A five-month-old girl was admitted to our institute because of the systolic blood pressure gradient of 42 mmHg between upper and lower extremities. Cineangiography revealed that the brachiocephalic artery originated from ascending aorta, while the left subclavian and left vertebral arteries took their origin from the descending aorta. However, the left common carotid artery was not visualized either on the angiogram or on the digital subtraction angiogram. No other associated cardiovascular anomalies, such as patent ductus or ventricular septal defect, were found. Therefore the diagnosis of isolated interruption of the aortic arch (IAA) Celoria-Patton type C, was made. As the heart failure gradually progressed, the aortic arch reconstruction with a extended polytetrafluoroethylene graft of 10 mm in diameter under extracorporeal circulation utilizing separate ascending aortic cannulation were performed. Her postoperative course was uneventful. The majority of cases with IAA associated with cardiac anomalies require surgical intervention in the neonatal period or in infancy. However, clinical course of isolated IAA generally resembles to that of the post ductal coarctation of the aorta, and most of the isolated interruption is diagnosed in adulthood. The infant is the youngest case with isolated IAA undergone aortic arch reconstruction with success ever reported in the literature.

Aorta, Thoracic↗
PubMed1994

[Anomalous origin of the right pulmonary artery from the ascending aorta: a report of eight cases].

We report eight cases with anomalous origin of the right pulmonary artery from ascending aorta. The ages at operation ranged from five days to fifteen years (average two years and seven months) with the body weights ranging from 1,610 g to 47.5 kg. Two patients underwent a surgical intervention in infancy; one of them with the body weight of 1,610 g was the smallest case previously reported in Japan. Associated cardiothoracic anomalies were patent ductus arteriosus (PDA) in five patients, atrial septal defect (ASD), PDA with ASD, tetralogy of Fallot with absent pulmonary valve in each one patient. Preoperative systolic pressure of pulmonary trunk were varied 83 to 115 mmHg (mean 94.7 mmHg). The continuity between pulmonary trunk and detached right central pulmonary artery was restored by a direct side-to-end anastomosis either behind (anatomical route) or in front of (non-anatomical route) the ascending aorta in all but one patient. There were one operative death and one hospital death. Postoperative pulmonary pressure was lower in patients with anatomical route than in patients with non-anatomical route. We conclude that successful surgical repair can be achieved by a direct anastomosis between abnormal detached central pulmonary artery and pulmonary trunk behind the ascending aorta even in infancy or early in childhood.

Adolescent↗