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Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 235 records · Page 13Linked to original sources
PubMed1996

[An aged case of successful repair for the ruptured distal aortic arch aneurysm associated with aortic regurgitation: a case report].

Ruptured thoracic aortic aneurysm had severely high mortality. A 83-year-old female, who had suddenly complained back pain and been diagnosed as the ruptured distal aortic arch aneurysm with aortic regurgitation by computer tomography and echo cardiogram, was admitted for an emergent surgery. Aortic arch replacement and aortic valve replacement were performed through median sternotomy under deep hypothermic circulatory arrest with the retrograde cerebral perfusion. She was complicated with respiratory ventilation failure due to the massive mediastinal hematoma and her chest was kept open postoperatively. Her chest was closed two days after the first operation and she recovered uneventfully.

Aged↗
PubMed1996

[Hypothermic management of brain dead dogs].

For preventing graft failure, the effects of hypothermic management of brain dead dogs was investigated. Forty-three brain dead dogs were divided into two groups according to the degree of esophageal temperature; a normothermic group (37.2 +/- 0.3 degree C, mean +/- SEM, n = 22), and a hypothermic group (31.8 +/- 0.3 degree C, n = 21) which was obtained by introducing ice slush in the peritoneal cavity. During the management of brain dead dogs, 1) heart rate, pressure product, and a total amount of catecholamine were significantly lower (p < 0.05) in the hypothermic group than in the normothermic group, 2) mean blood pressure, the maximum rate of the rise of left ventricle (LVdp/dt) and cardiac output were not different between both groups, 3) lactate content in the coronary sinus, and O2-extraction rate of the heart tended to be lower in the hypothermic group than in the normothermic group. After transplantation, the recovery of cardiac function was better in the hypothermic group than in the normothermic group. Hypothermic management of brain dead dogs may safely decrease cardiac stress, and keep cardiac aerobic circumstances.

Animals↗
PubMed1996

Long-term heart preservation by the combined method of simple immersion and coronary perfusion.

BACKGROUND: The combined method of cold storage and coronary perfusion for prolonged preservation of donor hearts was evaluated through preservation and transplantation with the use of 10 pair of adult mongrel dogs. METHODS: In situ initial flush for cooling and coronary vascular washout was performed with a University of Wisconsin solution. The heart was then removed and immersed into a cold (4degrees C) University of Wisconsin solution. After 12-hour cold storage, 1-hour preservation was added by coronary perfusion using a 4degree C oxygenated University of Wisconsin solution. High-energy phosphate (phosphocreatine, beta-adenosine triphosphate) and phosphate were measured by 31P-nuclear magnetic resonance spectroscopy at 0-hour cold storage, 12-hour cold storage, and immediately after coronary perfusion. RESULTS: Phosphocreatine and beta-adenosine triphosphate decreased to 12.1 +/- 24.2% (mean +/ standard deviation), 37.4% +/- 25.0%, respectively, after 12-hour cold storage, and significantly increased to 94.0% +/- 48.7% (p < 0.001), 48.8% (p < 0.05), respectively after 1-hour coronary perfusion. Disorder of nuclear arrangement and edema of muscular cells, which were observed after cold storage, were histologically restored after 1-hour coronary perfusion. After transplantation of preserved grafts, left ventricular pressure and left ventricular rate of pressure rise were evaluated in the graft with 12-hour cold storage only (group A) and in the graft with 12-hour cold storage and 1-hour coronary perfusion (group B). Left ventricular pressure 2 hours after transplantation in group B recovered to 76.1% significantly (p < 0.01), compared with 51.9% in group A. Significantly higher values of left ventricular rate of pressure rise 2 hours after transplantation was observed in group B (83.0% +/ 12.7%) compared with group A (68.2% +/- 12.5%). CONCLUSIONS: These results indicate that the combined method of cold storage and coronary perfusion may be effective for myocardial protection during long-term preservation.

Adenosine↗
PubMed1996

Basic performance of a miniature intraventricular axial pump.

A miniature intraventricular axial pump for left ventricular (LV) support is under development. This pump was designed for placement in the LV cavity by insertion through the LV apex with the outlet located at the ascending aorta via the aortic valve. The basic hydrodynamic characteristics represented as a relationship between pump head (H) and flow (Q) showed a negative linear relationship under a constant head. This characteristic was generally the same as that obtained by other axial rotation pumps. However, the actual H-Q relationship was represented as anticlockwise "loops" caused by the contraction of the natural LV. The comparative in vitro data on these H-Q loops showed that the shape of the loops was changed drastically by the connecting condition between the pump and natural cardiovascular system.

Animals↗
PubMed1996

5-Lipoxygenase inhibitory and antihistamine activities of linetastine.

The ability of linetastine (TMK688, 1-[¿5'-(3"-methoxy-4"-ethoxycarbonyloxyphenyl)-2',4'-pentadieno yl¿ aminoethyl]-4-diphenylmethoxypiperidine, CAS 110501-66-1) to inhibit leukotriene production and to antagonize the effect of histamine was examined in comparison with the ability of azelastine, an antiallergic drug having an antihistamine activity. Linetastine and its active metabolite TMK777 (1-[¿5'-(3"-methoxy-4"-hydroxyphenyl)-2',4'-pentadienoyl¿ aminoethyl]-4-diphenylmethoxypiperidine, CAS 101619-11-8) inhibited the release of leukotrienes B4 and C4 from calcium ionophore-stimulated human leukocytes. The respective IC50 values of leukotriene B4 were 1.2 x 10(-7) mol/l and 8.6 x 10(-8) mol/l, and those of leukotriene C4 were 1.5 x 10(-7) mol/l and 7.1 x 10(-8) mol/l. Azelastine also inhibited the release of leukotriene B4 and C4, but its IC50 values were higher than 1 x 10(-5) mol/l. Linetastine at 1-10 mg/kg p.o. inhibited the increase in leukotriene B4 and C4 production in the lungs during late asthmatic responses in actively sensitized guinea-pigs. The effect of 3.2 mg/kg lasted for more than 16 b. Since repeated oral administration of linetastine, 1 mg/kg once a day for 7 successive days, showed the same inhibitory effect on the increase in respiratory resistance and the leukotriene production as single oral administration, the effect of linetastine was neither tachyphylactic nor cumulative. Azelastine at 10 mg/kg had no effect on the leukotriene production. Linetastine TMK777 and azelastine dose-dependently inhibited the histamine-induced contraction of isolated guinea-pig trachea in a noncompetitive manner, the respective pD2 values were 7.28, 7.98 and 8.07. Linetastine inhibited histamine-induced bronchoconstriction dose-dependently at 1-10 mg/kg (p.o.) in guinea-pigs, and the effect lasted for more than 24 h. Repeated oral administration of linetastine, 0.32 to 3.2 mg/kg once a day for 7 successive days inhibited the histamine-induced bronchoconstriction, the same as single oral dosing. Azelastine at 0.32 mg/kg p.o. also showed antihistamine activity. In conclusion, linetastine inhibits both the production of leukotrienes and the effect of histamine at almost the same dose and the effects were long lasting.

Animals↗
PubMed1996

[Clinical evaluation of urinary leukotriene E4 levels in asymptomatic bronchial asthma].

To evaluate the significance of peptide leukotrienes (LTC4, D4, E4) in asymptomatic asthmatic patients, we measured urinary LTE4 levels which is thought to reflect in vivo production of peptide LTs. Urinary LTE4, was extracted using C18 solid phase column and measured by radioimmunoassay. There was no significant difference in urinary LTE4 levels among asthmatics with different severity or between atopic and non-atopic asthmatics. Urinary LTE4 levels were significantly elevated in asthmatics compared with normal controls (p < 0.05). When compared with normal controls, urinary LTE4 levels were significantly elevated in moderate to severe asthma (p < 0.05), and non-atopic asthmatics (p < 0.001). Urinary LTE4 levels were significantly elevated in aspirin-sensitive asthmatics compared with aspirin-tolerant asthmatics (p < 0.05). There was no significant difference in urinary LTE4 levels among aspirin-sensitive asthmatics with different severity. These results suggest that increased production of peptide LTs is a characteristic in aspirin-sensitive asthma, and that the severity and type of asthma and the presence of aspirin-sensitive asthma should be taken into consideration in the analysis of urinary LTE4 levels.

Adult↗
PubMed1995

Coronary arterial flow-velocity dynamics in children with angiographically normal coronary arteries.

BACKGROUND: There have been few reports about coronary hemodynamics in children during the process of growth. In the present study, to assess the characteristics of coronary flow dynamics in children, we examined the phasic coronary flow-velocity (CFV) patterns at rest and during peak hyperemic responses in children with angiographically normal coronary arteries. METHODS AND RESULTS: Spectral Doppler phasic coronary flow velocity was recorded with a 0.018-in intracoronary Doppler guidewire at rest and during peak responses after intracoronary bolus injection of ATP in 30 patients with Kawasaki's disease (age, 8.2 +/- 5.1 years; 24 boys and 6 girls) without angiographic coronary lesions. Average peak velocity (APV), maximum peak velocity (MPV), and diastolic-to-systolic velocity ratio (DSVR) were evaluated in the left anterior descending coronary artery (LAD), left circumflex artery (LCx), and right coronary artery (RCA). Coronary vasodilator reserve (coronary flow reserve [CFR]) was calculated as the ratio of ATP-induced hyperemic to baseline APV. Flow-velocity parameters in RCA were significantly lower than those in the LAD and LCx in both proximal and distal portions. Although the distal LCx had significantly lower values of APV and MPV than did the proximal LCx, there was no significant difference between the proximal and distal portions of the LAD and RCA for APV and MPV. All three coronary vessels showed a diastolic dominant flow pattern in each segment. This coronary flow pattern was less marked in the RCA than in the LCA. All three coronary vessels showed a significant increase in APV and a significantly decrease in DSVR after ATP administration. CFR was significantly lower in the LCx than in the LAD or RCA (P < .01: 1.93 +/- 0.34 in LCx versus 2.32 +/- 0.42 in LAD and 2.37 +/- 0.44 in RCA). From the view of aging, it was revealed that APV values in three vessels were higher in the younger group than in the older group. CFR values in the LAD and LCx were significantly lower in the younger group than in the older group (P < .001 in LAD: 2.01 +/- 0.28 in the younger versus 2.53 +/- 0.37 in the older; P < .01 in LCx: 1.61 +/- 0.15 in the younger versus 2.06 +/- 0.31 in the older). In addition, intracoronary injection of ATP did not increase the absolute angiographic coronary luminal diameter. CONCLUSIONS: With the use of an intracoronary Doppler guidewire, we demonstrated that there are some characteristic findings in CFV dynamics in childhood. These physiological characteristics in CFV dynamics that occur with aging and occur in each vessel must be taken into consideration in the study of the coronary circulation in children.

Adenosine Triphosphate↗
PubMed1995

[A case of postoperative hyponatremia caused by Sheehan syndrome associated with lung carcinoma].

A 54-year-old woman underwent a left upper lobectomy for lung carcinoma after which hyponatremia developed within 5 days. Her serum concentration of ADH was within normal range disapproving the presence of SIADH frequently associated with lung carcinoma. An endocrinological examination showed panhypopituitarism. From her anamnesis it was seen that there was much perinatal bleeding and amenorrhea. She was diagnosed as suffering from Sheehan syndrome. She was treated with glucocorticoid and beneficial results were obtained. Her serum concentration of natrium returned to normal and she discharged on the 74th postoperative day. We present this paper because we had difficulty in determining that she had Sheehan syndrome, and think that a careful search for a diagnosis before operation is important for the management of the patient during the perioperative and postoperative period.

Adenocarcinoma↗
PubMed1995

Microsatellite alterations in adenoma and differentiated adenocarcinoma of the stomach.

In order to elucidate the significance of the adenoma-carcinoma sequence in gastric carcinogenesis from a genetic point of view, we examined microsatellite alterations (replication error and loss of heterozygosity) on chromosomes 2p (D2S123), 3p (D3S1317), 5q (D5S409), 9p (IFNA), and 13q (D13S153) as well as p53 gene mutations in 13 adenomas and 23 differentiated adenocarcinomas including 8 early carcinomas of the stomach. Replication error was detected in only one of the adenomas (8%, 1/13) at the D5S409 locus and in none at the other loci, and loss of heterozygosity was also an infrequent event found in one adenoma (14%, 1/7 informative cases) at D5S409 and in none at the other loci. A p53 gene mutation was detected in one (8%, 1/13) of the adenomas. Thus, microsatellite alterations and p53 gene mutations are rare events in adenomas. In differentiated adenocarcinomas, replication error was detected in 4 (17%, 4/23) at single or multiple loci, and loss of heterozygosity was observed frequently at D3S1317 (25%, 3/12), D5S409 (67%, 6/9), and IFNA (26%, 5/19). Mutations in the p53 gene were detected in 9 (39%, 9/23) of the differentiated adenocarcinomas. Microsatellite alterations on several chromosomes and mutations in the p53 gene were frequent in differentiated adenocarcinomas, even those at an early stage. These results suggest that the adenoma-carcinoma sequence is relatively rare in gastric carcinogenesis, and that the majority of differentiated adenocarcinomas of the stomach may develop through a de novo pathway.

Adenocarcinoma↗
PubMed1995

The sequential accumulation of genetic alterations characteristic of the colorectal adenoma-carcinoma sequence does not occur between gastric adenoma and adenocarcinoma.

We screened 30 gastric adenomas and 72 gastric adenocarcinomas for four genetic alterations (mutations of the K-ras, APC, and p53 genes and loss of heterozygosity at the DCC genetic locus) which are known to occur during colorectal tumourigenesis. We used polymerase chain reaction (PCR) single-strand conformation polymorphism analysis to detect mutations. Loss of heterozygosity (LOH) at the DCC locus was ascertained directly by performing PCR on the variable number of tandem repeats within the gene. Mutations of the K-ras gene were not detected in any gastric adenoma or carcinoma. APC mutations were detected in 20 per cent (6/30) of the adenomas but in only 1.4 per cent (1/72) of the carcinomas. In contrast, the p53 gene was frequently mutated in carcinomas (35 per cent; 25/72), but not in adenomas. LOH at the DCC locus was a frequent occurrence in carcinomas (58 per cent; 11/19 informative cases) but was infrequent in adenomas (14 per cent; 1/7). Alterations of the p53 and DCC genes occurred frequently both in differentiated and in undifferentiated gastric carcinomas. The considerable differences in the incidences of genetic alterations between gastric adenoma and carcinoma indicate that the sequential development of gastric carcinoma from adenoma is uncommon in gastric carcinogenesis.

Adenocarcinoma↗
PubMed1995

Successful surgical management of emphysematous giant bullae accompanied by severe bronchial asthma: report of a case.

The surgical treatment of emphysematous lung bullae is usually contraindicated in patients with severe bronchial asthma. However, we recently encountered a patient who required surgery due to the development of respiratory distress despite treatment with bronchodilators and low-dose prednisolone (5 mg/day). During the first operation, bronchospasm occurred with anesthesia. After suppression of the asthmatic symptoms for 2 weeks with high-dose prednisolone (25 mg/day), the giant bullae could be resected safely. Thus, the preoperative resolution of asthma to decrease the probability of an attack is indispensable for such patients.

Adult↗
PubMed1995

Screening for abdominal aortic aneurysm and occlusive peripheral vascular disease in Japanese residents.

To evaluate the prevalence of abdominal aortic aneurysm (AAA) and occlusive peripheral vascular disease (PVD) in Japanese residents, and to examine the correlations between these diseases and the risk factors of atherosclerosis, 348 residents of a village in central Japan aged between 60 and 79 years were screened. The screening for AAA was performed using ultrasonography (US) and that for PVD was performed by palpation and Doppler US. No AAA was found, and a right common iliac arterial aneurysm was detected in a 79-year-old man (0.3%). The mean diameter of the infrarenal abdominal aorta was 18.7 mm and an abdominal aorta of 25 mm or greater in diameter was seen in 16 participants (4.6%), all of whom need to be followed up. PVD was suspected in two patients (0.6%) with a low ankle brachial pressure index. Of a total of five patients diagnosed or suspected of having a common iliac arterial aneurysm or PVD, four (80%) had at least one risk factor for atherosclerosis. Thus, we conclude that Japanese residents with risk factors predisposing them to atherosclerosis such as hypertension, obesity, abnormal serum lipid levels, and a history of smoking should be selectively screened for AAA and PVD due to the low prevalence of these diseases and from the viewpoint of cost-effectiveness.

Aged↗
PubMed1995

Effects of beraprost sodium, a new prostaglandin I2 analog, on parameters of hemostasis, fibrinolysis, and myocardial ischemia in patients with exertional angina.

The purpose of this study was to investigate the effects of beraprost sodium, a stable prostacyclin analog, on the parameters of hemostasis, fibrinolysis, and myocardial ischemia in patients with exertional angina. Thirty-one patients with exertional angina who had significant organic coronary artery stenosis in at least one of the three major coronary arteries were selected. All patients underwent quantitative exercise thallium-201 emission computed tomography before and 1 month after 120 micrograms per day of beraprost sodium administration. Before exercise, blood samples were collected from 8:30 a.m. to 9:30 a.m. after the patients had been lying in bed undisturbed for at least 10 minutes. Plasma platelet factor 4 (PF4), fibrinopeptide A (FPA), tissue plasminogen activator antigen (t-PA), and plasminogen activator inhibitor-1 activity (PAI-1) were measured. There were no significant differences in exercise parameters on both exercise tests. However, both the extent and severity scores of ischemia were significantly aggravated (p < 0.05 for both) during beraprost sodium administration. Plasma FPA levels decreased significantly during beraprost sodium administration (p < 0.01). Likewise, plasma PF4 levels decreased significantly during beraprost sodium administration (p < 0.05). As for plasma t-PA antigen levels, there was no significant difference before versus during beraprost sodium administration. Plasma PAI-1 activity levels decreased significantly during beraprost sodium administration (p < 0.05). The results indicate that beraprost sodium has strong antithrombogenic properties. However, its aggravation of myocardial ischemia may limit clinical usage.

Angina Pectoris↗
PubMed1995

Physical-strength tests and mortality among visitors to health-promotion centers in Japan.

A follow-up study was conducted to clarify the relationship between physical-strength level and risk of death from all causes and from cancer and cardiovascular disease. The 7286 persons who were examined at seven health-promotion centers throughout Japan between 1982 and 1987 were followed up. By January 1992, 6259 persons (85.9%) had been contacted by questionnaire. They included 3117 men (49.8% of all subjects studied) (average age 53.6 years at baseline, SD = 9.0 years, range 40-84 years), and 3142 women (50.2%) (average age 54.5 years at baseline, SD = 8.5 years, range 40-85 years). The follow-up period for each person averaged 6.1 years, for a total of 38,253 person-years. During this period, 155 deaths were reported. At baseline, five physical-strength tests (grip strength, side step, vertical jump, standing trunk flexion, and sit-ups) were performed. Five clinical laboratory tests (thickness of skinfold, blood sugar, total serum cholesterol, percent vital lung capacity, and blood pressure) were also conducted. The examinees were questioned about smoking status (current smoker, nonsmoker, and ex-smoker). Men with thicker skinfold [relative risk (RR) = 2.11] and higher levels of blood sugar (RR = 1.89) had an excess risk of death from all causes. Men with higher serum cholesterol (RR = 5.08), thicker skinfold (RR = 4.54), and elevated blood pressure (RR = 2.33) had an excess risk of death from cardiovascular disease. In women, no relationship was seen between clinical laboratory tests and an excess risk of death. Men exhibiting lower values for side step (RR = 2.43), vertical jump (RR = 2.37), sit-ups (RR = 1.93) and grip strength (RR = 1.92) also had an excess risk of death from all causes. Furthermore, men with lower heights for vertical jump (RR = 5.51) had an excess risk of death from cardiovascular disease. After adjustment for skinfold thickness, blood sugar, total serum cholesterol, blood pressure, percent vital lung capacity and smoking status, men with a lower level of side step, vertical jump, and grip strength had an excess risk of death from all causes. No such relationship was seen between physical-strength level and an excess risk of death in women. It is concluded that a low level of physical strength might be significantly correlated with subsequent health outcomes in men.

Adult↗
PubMed1995

Epithelial-cadherin gene is not mutated in ductal carcinomas of the breast.

We investigated mutations of the epithelial (E)-cadherin gene and loss of heterozygosity (LOH) at flanking loci using three microsatellite markers on the long arm of chromosome 16 in 25 ductal carcinomas of the breast. Expression of E-cadherin was also investigated immunohistochemically. No mutations were detected in exons 6 through 9 of the E-cadherin gene. LOH was observed more frequently (42%) at D16S402 (16q-ter) than at D16S421 (16q22.3-q23.1) (17%), which is located near the E-cadherin gene. Expression of E-cadherin was observed at the cell borders in 92% (11/12) of the tumors examined. The absence of mutations in the E-cadherin gene and its conserved expression suggest that inactivation of E-cadherin does not contribute significantly to the invasion or metastatic potential of ductal carcinomas of the breast. Furthermore, the high frequency of LOH at 16q-ter suggests the existence of another tumor suppressor gene which may play a crucial role in the genesis of ductal carcinomas of the breast.

Adenocarcinoma, Scirrhous↗
PubMed1995

Loss of heterozygosity on the short arm of chromosome 9 without p16 gene mutation in gastric carcinomas.

A putative tumor suppressor gene, p16 (MST1; multiple tumor suppressor 1/CDK4I; cyclin-dependent kinase 4 inhibitor), was isolated and mapped on the short arm of chromosome 9 (9p). The significance of p16 mutations in gastric tumorigenesis was examined by assessing p16 mutations as well as loss of heterozygosity (LOH) on 9p in 13 gastric adenomas and 45 adenocarcinomas. LOH on 9p (IFNA; alpha-interferon locus) was detected in 22% (5/23 informative cases) of differentiated adenocarcinomas, 10% (1/10) of undifferentiated carcinomas and none (0/6) of the adenomas. Although we found a sequence polymorphism at the second position of codon 99 (CGC/CAC) of the p16 in one gastric adenoma patient, no somatic mutations were detected in any of the gastric adenomas or adenocarcinomas. These results suggest that p16 mutations probably do not contribute to gastric tumorigenesis. However, these data suggest that another tumor suppressor gene on 9p (near the IFNA locus) may contribute to the progression of differentiated adenocarcinoma of the stomach.

Adenocarcinoma↗