Biomedical subjects

Hiroyuki Nakajima

Publications and source records attributed to Hiroyuki Nakajima.

51 records · Page 3Linked to original sources

PubMed2003

Newly designed soft prelooped cap for endoscopic mucosal resection of gastric lesions.

BACKGROUND: Endoscopic mucosal resection with a cap-fitted panendoscope is a useful, effective, and safe technique. The effectiveness and safety of a newly designed larger but softer cap was compared in this study with the conventional hard cap. The soft cap has a significantly larger diameter (18 mm) compared with that of the hard cap (16.5 mm). METHODS: Eighty-three patients who underwent mucosal resection of gastric lesions were included in analysis. The diameter, resection specimen depth, and the rate of en bloc resection were compared. The operability of the endoscope with the cap attached, patient tolerance, and safety of the procedure were analyzed. RESULTS: Mean diameter (+/- SEM) of specimens resected with the soft cap was larger: 22.1 (+/- 0.7) versus 15.8 (+/- 0.3) mm (p < 0.001). The specimen was also thicker: 1.54 (+/- 0.10) versus 1.08 (+/- 0.11) mm (p < 0.001). Use of the soft cap led to higher rate of en bloc resection: 66.7% versus 43.2% (p < 0.05). The operability of the endoscope with the larger, softer cap attached was similar to that when the hard cap was used. Both caps were equally safe. CONCLUSION: The soft cap is safe and useful for mucosal resection of larger gastric lesions. Its use increases the rate of en bloc resection.

Aged↗

PubMed2003

Early adaptation of the left internal thoracic artery as a blood source of y-composite radial artery grafts in off-pump coronary artery bypass grafting.

OBJECTIVE: Y-composite grafting with the radial artery (RA) is often used in off-pump coronary artery bypass grafting (OPCAB). However, the early flow reserve of the left internal thoracic artery (LITA) as a blood source of the Y-composite RA graft has not been delineated. METHODS: The size of the LITA was examined angiographically in 42 patients who underwent OPCAB using LITA and Y-composite RA grafting between June 2000 and February 2002. In these patients, the LITA was used as a blood source of the Y-composite RA graft. The mean patient age +/- SD was 67 +/- 8 years. The average number of d i stal anastomoses was 3.2 +/- 0.7. Total coronary revascularization was carried out in 34 patients with only LITA and Y-composite RA grafting. RA grafting was used for revascularization of the circumflex artery alone in 5 patients, for the right coronary artery system (RCS) alone in 6 patients, and for both the circumflex and the RCS in 23 patients. The average number of distal anastomoses using the RA was 1.9 +/- 0.7. Flow measurements of the proximal LITA were achieved intraoperatively with a transit-time flowmeter. The diameters of the LITA before and after the operation were measured angiographically. Intraoperative flow volume was correlated with the ratio of the LITA diameters before and after the operation. RESULTS: The mean flow rate of the LITA was 61 +/- 35 mL/min (range, 9-196 mL/min). The mean diameters of the LITA before and after the operation were 1.97 +/- 0.36 mm and 2.74 +/- 0.60 mm, respectively. The mean ratio of the LITA diameter after the opera t ion to that before the operation was 1.43 +/- 0.27. The intraoperative flow volume was positively correlated with the ratio of LITA diameters (r = 0.414; P =.006). CONCLUSION: These results demonstrate the early adaptation of the LITA as a blood source of the Y-composite RA graft in OPCAB and the rationale for using the LITA as a single blood source for total coronary artery revascularization.

Aged↗

PubMed2002

The effect of cryo-maze procedure on early and intermediate term outcome in mitral valve disease: case matched study.

BACKGROUND: The maze procedure is an effective way to treat atrial fibrillation (AF) associated with mitral valve disease. In a last several years, cryoablation was substituted for atrial incision in many reports to simplify the maze procedure. However, there has been no comparative study to delineate the feasibility of the use of cryoablation. METHODS AND RESULTS: We compared the early and intermediate-term results of the maze procedure including pulmonary venous isolation from the left atrium using cryoablation (CM) with our conventional (Kosakai) maze procedure (KM) including encircling incision around the orifices of pulmonary veins. One hundred and 10 pairs of patients were matched in the age, left atrial dimension >70 mm, duration of AF >0 years, previous cardiac surgery, mechanical valve implantation and concomitant aortic valve procedures. CM required significantly shorter cardiopulmonary bypass time (186+/-56 minute versus 214+/-47 minute, P=0.001) and aortic cross-clamp time (134+/-43 minute versus 144+/-37 minute, P=0.03) than KM with less chest tube drainage (590+/-353 mL versus 745+/-618 mL, P=0.02) for 12 hours after operation. The sinus rhythm restoration rate in CM group (85.4%) was comparable with KM group (86.4%) at discharge. In the late results, the actuarial freedom from recurrence of sustained AF at 3 years in CM group (97.7%) was not significantly (P=0.11) different from that in KM group (90.4%). The actuarial freedom from stroke at 3 years in CM group was 99.0%. CONCLUSION: The modification of the maze procedure including cryoablation for pulmonary venous isolation provided less aortic cross-clamp time and less amount of chest tube drainage with the comparable recovery and maintenance of sinus rhythm with KM. CM is a reliable and less invasive surgical option for the AF associated with mitral valve disease.

Atrial Fibrillation↗

PubMed2002

Maze procedure and cor triatriatum repair.

A 39-year-old man had cor triatriatum (Lucas-Schmidt type IA) with severe mitral regurgitation and atrial fibrillation. We performed resection of the anomalous septum between the accessory chamber and the left atrium, and conducted mitral valve repair and the maze procedure. The patient regained sinus rhythm and normal pulmonary venous drainage to the left ventricle without mitral regurgitation. Histological examination demonstrated fibrotic myocardial structures in the anomalous septum. The maze procedure and complete excision of the anomalous septum proved to be effective surgical treatment for atrial fibrillation with cor triatriatum.

Adult↗

PubMed2002

Genetic manipulation and quantitative-trait loci mapping for nitrogen recycling in rice.

Immunocytological studies in this laboratory have suggested that NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14) in developing organs of rice (Oryza sativa L. cv. Sasanishiki) is involved in the utilization of glutamine remobilized from senescing organs through the phloem. Because most of the indica cultivars contained less NADH-GOGAT in their sink organs than japonica cultivars, over-expression of NADH-GOGAT gene from japonica rice was investigated using Kasalath, an indica cultivar. Several T0 transgenic Kasalath lines over-producing NADH-GOGAT under the control of a NADH-GOGAT promoter of Sasanishiki, a japonica rice, showed an increase in grain weight (80% as a maximum), indicating that NADH-GOGAT is indeed a key step for nitrogen utilization and grain filling in rice. A genetic approach using 98 backcross-inbred lines (BC(1)F(6)) developed between Nipponbare (a japonica rice) and Kasalath were employed to detect putative quantitative trait loci (QTLs) associated with the contents of cytosolic glutamine synthetase (GS1; EC 6.3.1.2), which is probably involved in the export of nitrogen from senescing organs and those of NADH-GOGAT. Immunoblotting analyses showed transgressive segregations toward lower or greater contents of these enzyme proteins in these BC(1)F(6). Seven chromosomal QTL regions were detected for GS1 protein content and six for NADH-GOGAT. Some of these QTLs were located in QTL regions for various biochemical and agronomic traits affected by nitrogen recycling. The relationships between the genetic variability of complex agronomic traits and traits for these two enzymes are discussed.

Amino Acid Oxidoreductases↗

PubMed2002

Perioperative advantages of off-pump coronary artery bypass grafting.

For the first time in Japan, off-pump coronary artery bypass grafting (OPCAB) was compared with the conventional on-pump technique, retrospectively examining the morbidity associated with coronary artery bypass grafting (CABG) and assessing the efficacy of OPCAB. In 2000, 158 patients underwent CABG: 95 patients (60%) had OPCAB (Group I) and 63 patients (40%) had conventional CABG (Group II). The operating time, length of intensive care unit (ICU) stay, ventilation time, postoperative bleeding, transfusion, postoperative renal function, occurrence of stroke, and early graft patency were examined in both groups. There were no hospital deaths in either group. The operating time, ICU stay, and ventilation time were significantly (p < 0.0001, p = 0.013, and p < 0.0001, respectively) shorter in Group I (351 +/- 85 min, 3.0 +/- 1.4 days, and 5.1 +/- 2.8h) than in Group II (449 +/- 112 min, 3.6 +/- 1.8 days, and 13.7 +/- 18.0 h). The postoperative blood loss within 12h and the transfusion volume were significantly (p = 0.0004 and p < 0.0001, respectively) smaller in Group I (480 +/- 210 ml and 300 +/- 490ml) than in Group II (720 +/- 430ml and 1,230 +/- 1,180 ml). Peak serum blood urea nitrogen and creatinine concentrations (excluding patients with preoperative chronic renal failure, ie a preoperative serum creatinine > 1.5 mg/dl) were significantly (p < 0.0001 and p < 0.0001, respectively) lower in Group I (16.2 +/- 15.2mg/dl and 0.81 +/- 0.72 mg/dl) than in Group II (19.2 +/- 7.6 mg/dl and 0.92 +/- 0.28 mg/dl). There were no perioperative strokes in Group I, but 6.4% of Group II patients suffered a stroke. There was no significant difference in graft patency between the groups (95.6% vs 94.9%). OPCAB reduced the mortality and morbidity of coronary revascularization, with a shorter operating time and more rapid recovery from surgery.

Aged↗

PubMed2002

Total arterial off-pump coronary revascularization with only internal thoracic artery and composite radial artery grafts.

OBJECTIVE: Total arterial off-pump coronary artery bypass (OPCAB) grafting with only internal thoracic artery (ITA) and composite radial artery (RA) grafts has been applied extensively to avoid cerebral complications and late vein graft failure. We evaluated the initial experience with this method by clinical and angiographic study. METHODS: Between April 2000 and May 2002, 257 patients underwent OPCAB grafting with this technique. The range of ages at operation was 42 to 86 years (mean, 66.1 +/- 8.6 years). On average, 3.28 +/- 0.86 grafts per patient were completed. More than 4 distal anastomoses were performed in 88 patients (34%). For coronary revascularization, 289 ITA and 555 RA grafts were used. The RA was used as a Y graft in 211 patients, as an I graft (for ITA extension) in 52 patients, and as a K graft (the side of the RA attached to the side of the left ITA) in 28 patients. Sequential bypass grafting was performed with 190 RA and 7 ITA grafts. The sites of distal anastomoses were 256 left anterior descending arteries (30%), 236 posterolateral branches (28%), 144 posterior descending arteries (17%), 106 diagonal branches (13%), 82 obtuse marginal branches (10%), and 19 right coronary arteries (2%). RESULTS: There were 1 operative death (0.4%) due to cerebral hemorrhage and 2 episodes of stroke (0.8%) during postoperative angiography. There were no clinical underperfusion syndromes or new intra-aortic balloon pump insertions. Perioperative myocardial infarction occurred in 12 patients (4.7%), sternal dehiscence in 5 (1.9%), and early coronary intervention in 4 (1.6%). There was no deep wound infection, reexploration for bleeding, or hand ischemia. The actuarial survival rate and the cardiac event-free rate at 2 years were 98.6% +/- 2.4% and 94.2% +/- 0.8%, respectively. Early postoperative angiography revealed a 97.8% (264/270) graft patency of ITAs and 97.9% (512/523) graft patency of RAs in 238 patients. Flow competition of the RA graft was recognized in 22 patients and, as indicated by follow-up angiographic study, did not cause late graft occlusion. CONCLUSIONS: OPCAB grafting with ITAs and composite RAs provides excellent early and intermediate clinical results and graft patency.

Adult↗

PubMed2002

Studies on the metabolic fate of m17055, a novel diuretic (5): pharmacokinetics and pharmacodynamics of unchanged drug in rat and dog after intravenous administration of M17055.

The pharmacokinetics and pharamacodynamics of M17055, a novel diuretic were studied after a single intravenous administration to rats and dogs, the two species used in the pharmacological and toxicological studies. No gender dependent response to systemic exposure was observed at the high dose level in rats, in agreement with the determined LD(50). A gender difference in urinary excretion of M17055, however, was clearly observed in rats. The slower elimination and the lower total body clearance (CLtot) values of M17055 in dogs reflect the difference of the no-effect level (NOEL) between rats (0.1 mg/kg) and dogs (0.03 mg/kg) well. The diuretic response was well correlated with the urinary M17055 excretion rate by fitting to a sigmoid E(max) model in both rats and dogs. The derived ER(50) value of M17055 in dogs was approximately 10 times less than that reported for furosemide, suggesting that the intrinsic potency of M17055 is equal to or higher than those of other powerful loop diuretics. Although diuretic sensitivity was considered to be lower in dogs than in rats, the higher amount of M17055 reaching the dog kidney is likely to compensate for this. The diuretic response in female rats was predictable by using the pharmacodynamic parameters derived from male rats. These results show that the apparent high diuretic potency and the other pivotal observations for M17055 found in the pharmacological and toxicological studies can be rationalized by the pharmacokinetic and pharmacodynamic properties of the unchanged compound.

Journal Article↗

PubMed2002

Studies on the metabolic fate of M17055, a novel diuretic (4): species difference in metabolic pathway and identification of human CYP isoform responsible for the metabolism of M17055.

The metabolic profile of M17055, a novel diuretic, after administration to experimental animals and after incubation with human liver microsomes was investigated. 1. Extensive metabolism was observed in rats and monkeys and the structures of six metabolites (RU1, RU2, and RU3 from rat urine or liver perfusate; MU1, MU2 and MU3 from monkey urine) were assumed or identified. The clear species difference of metabolism was revealed between rats and a monkey with different structures of the isolated metabolites. 2. When these metabolites were quantified using radioactive material, RU3, RU1 and MU3 were considered to be major metabolites in rat urine, rat bile and monkey urine respectively, while in a dog, unchanged drug was observed as the major component indicating only little metabolism occurred in dog, when administered intravenously. 3. RU1 and RU2 were also generated from [(14)C]M17055 after incubation with human liver microsomes, suggesting that the metabolic pathway of M17055 in humans involves that observed in rats. 4. [(14)C]M17055 metabolism in human liver microsomes was inhibited by CYP2C8/9 and CYP3A4/5 inhibitors, and also by the antibodies that recognize CYP2C8/9/19 and CYP3A4. Significant correlations were observed between the rate of [(14)C]M17055 metabolism and the activity of testosterone 6beta-hydroxylation or tolbutamide methyl-hydroxylation. cDNA-expressed CYP3A4 and CYP2C9 could catalyze the metabolism of [(14)C]M17055. These results suggest that the metabolism of M17055 in human liver microsomes is catalyzed mainly by CYP3A4 and CYP2C9.

Journal Article↗

PubMed2002

Eight-year experience of combined valve repair for mitral regurgitation and maze procedure.

BACKGROUND AND AIMS OF THE STUDY: Although atrial fibrillation (AF) is often associated with severe mitral regurgitation (MR), a simultaneous maze procedure for AF associated with repair of MR remains controversial. In this study, mid-term results of combined mitral valve repair and the maze procedure were examined. METHODS: Between May 1992 and April 2001, 85 patients (61 males, 24 females) underwent valve repair for MR and the maze procedure. Mean age at surgery was 61.8+/-9.1 years; mean follow up was 4.7+/-2.3 years. Valve lesions were anterior in 26 patients (31%), posterior in 31 (36%), anterior + posterior in 23 (27%), and simple dilated annulus in five (6%). Chordal replacement with expanded PTFE sutures was performed in 40 patients (47%), and leaflet resection in 41 (48%). Ring annuloplasty was also applied in 61 patients (72%). Associated procedures were tricuspid valve annuloplasty in 33 (36%), coronary artery bypass grafting in four, atrial septal defect closure in two, aortic valve repair in one, and resection of abnormal septum in the left atrium in one. RESULTS: There was one hospital death (1%), and one late death (1%). Reopening the chest for bleeding was necessary in six cases (7%). One thromboembolic episode was detected during follow up (0.25%/patient-year). Reoperation for MR was performed in three patients (4%). Actuarial event-free survival rate was 90.0+/-6.4% at eight years. Sinus rhythm was regained in 68 patients (81%), and atrial A-wave was detected in 57 (68%) by pulsed Doppler study. Postoperative left ventricular diastolic and systolic dimensions were significantly (p = 0.001 and p = 0.017) smaller in patients who restored sinus rhythm than in those who did not (48.6+/-4.6 versus 54.6+/-4.7 mm, and 33.0+/-6.0 versus 38.1+/-6.9 mm). CONCLUSION: Combined mitral valve repair for MR and the maze procedure showed satisfactory midterm results. Postoperative sinus rhythm conversion by the maze procedure may reduce left ventricular size, and the incidence of thromboembolic episodes in mitral valve repair.

Adult↗

PubMed2002

Multiple off-pump coronary revascularization with "aorta no-touch " technique using composite and sequential methods.

BACKGROUND: Although off-pump coronary artery bypass grafting (OPCAB) has been widely applied in patients who are considered high risk for cardiopulmonary bypass (CPB), there is still a risk of stroke during the operation because of the ascending aortic partial clamp for proximal anastomosis. In the present study, we report the initial results of an "aorta no-touch " technique using an in-situ graft and composite and sequential grafting methods. METHODS: Between March 2000 and April 2001, 120 patients underwent OPCAB with this technique. The age of patients ranged from 47 to 86 years, with a mean age of 65.7 +/- 8.7 years. On average, 3.12 +/- 0.77 grafts per patient were completed. More than 4 distal anastomoses were performed in 32 patients (27%). As in-situ grafts, 140 internal thoracic arteries (ITAs) and 9 gastroepiploic arteries were used. The radial artery (RA) was used as a Y composite graft in 91 patients, as an I composite graft in 25, and as a K composite graft in 2. Sequential bypass grafting was performed using the RA in 60 patients, the saphenous vein (SV) in 6, the ITA in 4, and the gastroepiploic artery (GEA) in 3. Arterial grafts were used in 92% (345/374) of total bypass grafts. Distal anastomosed sites were 119 left anterior descending arteries (LADs) (32%), 90 posterolateral branches (24%), 64 posterior descending arteries (17%), 49 diagonal branches (13%), 39 obtuse marginal branches (10%), and 13 right coronary arteries (3.5%). RESULTS: There was no operative death or stroke. Early postoperative angiography revealed 95.5% (321/336) graft patency with 100% patency (119/119) of ITA to LAD grafts. Graft patency of the ITAs and RAs (98.5% and 95.9%) were significantly better than that of the GEA (79.0%, p = 0.0064 and p = 0.030) and saphenous vein (82.3%, p = 0.011 and p = 0.048). CONCLUSION: OPCAB performed with the aorta no-touch technique using an in-situ graft and composite and sequential grafting methods provides excellent early clinical results and graft patency.

Aged↗

PubMed2002

[Intractable infective endocarditis associated with supraaortic stenosis in Williams syndrome: a case report].

A 17-year-old man with supravalvular aortic stenosis associated with Williams syndrome was admitted to our hospital for intensive treatment for intractable infective endocarditis. The patient had a history of percutaneous balloon valvuloplasty for aortic stenosis in 1992. He was well until late in 1999, when he had a high temperature after dental work-up. The diagnosis was infective endocarditis but antibiotic therapy was not effective. He was transferred to our clinic. Transthoracic echocardiography demonstrated bicuspid aortic valve, supraaortic stenosis, mitral valve prolapse with severe regurgitation and scattered vegetations on the anterior mitral and aortic valves. In addition, transesophageal echocardiography showed innumerable mobile vegetations located from Valsalva's sinus to the descending aorta. Aortic root and arch replacement with a homograft and mitral valve replacement with an artificial valve were successfully performed to eliminate the infective endocarditis. In the present patient, the flow jet across the supraaortic stenosis seemed to cause a predisposition to severe endocarditis.

Adolescent↗

PubMedDate not supplied

The effect of granisetron on in vitro metabolism of paclitaxel and docetaxel.

PURPOSE: Paclitaxel and docetaxel are effective anticancer agents; however, these agents can be associated with the debilitating side effects of nausea and vomiting, thereby necessitatingthe administration of concomitant antiemetic agents. This increases the potential fordrug-drug interactionsthrough inhibition or induction of the cytochrome P450 (CYP) enzymes. The 5-HT3-receptor antagonists are currently regarded as the antiemetic 'gold standard' and this study was undertaken to investigate the effects of granisetron on the metabolism of paclitaxel and docetaxel in human liver microsomal preparations in vitro. METHODS: Paclitaxel, 5 nM, and docetaxel, 1.25 nM, were incubated in the presence of granisetron, 0, 10, 100, and 1000 pM, in human liver microsomal preparations (500 microg). The levels of unchanged paclitaxel and docetaxel in the incubation mixture were determined by high-performance liquid chromatography. Ketoconazole, 10 nM, a potent inhibitor of CYP3A metabolism, served as a positive control. RESULTS: In the absence of granisetron, unchanged paclitaxel and docetaxel levels measured were 27.2 +/- 2.8% and 44.3 +/- 4.0% of control, respectively. Ketoconazole prevented the breakdown of both paclitaxel and docetaxel, to the degree that no unchanged paclitaxel or docetaxel was detected in the incubation mixture. Granisetron had no effect on the rate of reduction of either paclitaxel or docetaxel; unchanged paclitaxel and docetaxel decreased to 25.0 +/- 1.5%, 26.4 +/- 1.0%, and 27.6 +/- 6.4%, and 44.2 +/- 1.5%, 41.2 +/- 4.1%, and 43.1 +/- 0.5%, respectively. DISCUSSION: The results from this study suggest that granisetron neither inhibits nor induces the enzymes involved in the metabolism of paclitaxel or docetaxel. Thus, granisetron can be used safely as a supportive care agent to treat paclitaxel or docetaxel chemotherapy-induced nausea and vomiting with minimal risk of drug-drug interactions.

Analysis of Variance↗

PubMedDate not supplied

A more comprehensive left ventricular repair for severely dilated cardiomyopathy.

We report a patient with cardiogenic shock due to severely dilated cardiomyopathy who underwent complex, but comprehensive left ventricle (LV) repair. Preoperative investigation showed marked LV dilatation, poor LV function, severe mitral and tricuspid regurgitation, and total occlusion of two coronary arteries. We urgently performed (1) modified Batista operation which preserves the LV apex, (2) septal anterior ventricular exclusion (SAVE) operation, (3) mitral annuloplasty, (4) tricuspid annuloplasty, and (5) coronary bypass. Postoperative evaluation revealed good graft flow, reduced LV dimension preserving the elliptical shape, improved LV function, and minimal MR. Twenty-six months postoperatively, the patient has minimum clinical symptoms (NYHA: I).

Cardiac Surgical Procedures↗

PubMedDate not supplied

Advanced primary clear cell carcinoma of the vagina not associated with diethylstilbestrol.

BACKGROUND: Primary vaginal clear cell carcinoma occurs in young women exposed to diethylstilbestrol (DES) in utero. Primary vaginal clear cell carcinoma not associated with DES is very rare. We report the clinicopathologic and cytopathologic features of a patient with advanced, sporadic primary vaginal clear cell carcinoma with metastases to liver, lung and paraaortic lymph nodes. CASE: A postmenopausal, 63-year-old woman presented to our department with genital bleeding. A hemorrhagic tumor found in the vagina was diagnosed as a clear cell carcinoma by cytopathologic examination of the tumor smear and by histopathologic examination of a biopsy specimen. A chest radiograph revealed multiple lung metastases, and metastases to the liver and paraaortic lymph nodes were noted on computed tomography and magnetic resonance imaging. The tumor was diagnosed as primary clear cell carcinoma of the vagina, stage IVb (FIGO) based on a normal cytopathologic examination of the cervix, endometrium and ascites; normal appearance of the uterus, ovaries and kidneys on magnetic resonance imaging; and absence of detectable tumor in the urinary tract. The patient died of respiratory failure 31 days after hospitalization. The tumor demonstrated overexpression of p53 protein and did not show microsatellite instability. CONCLUSION: This patient was the second reported Japanese woman with advanced primary vaginal clear cell carcinoma not associated with DES.

Adenocarcinoma, Clear Cell↗