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Biomedical subjects

Hiroyuki Nakajima

Publications and source records attributed to Hiroyuki Nakajima.

At least 37 records · Page 2Linked to original sources
PubMed2005

Mitral valve repair and cryo-Maze procedure in Ehlers-Danlos syndrome.

A 48-year-old man presented with typical features of Ehlers-Danlos syndrome, such as soft and hyperextensible skin, subcutaneous nodules, clubbed feet, and a mild degree of pigeon chest. In addition, his past history revealed congenital dislocation of the hip joint, retinal detachment, and repeated episodes of congestive heart failure due to severe mitral regurgitation and atrial fibrillation. We subjected the patient to surgical repair of the mitral valve combined with the maze procedure, which proved successful.

Atrial Fibrillation↗
PubMed2005

Successful excision of a cystic tumor of the atrioventricular nodal region.

Cystic tumor of the atrioventricular nodal region is a rare cardiac primary tumor that can cause heart blockage and sudden death. Antemortem diagnosis and successful excision of the atrioventricular nodal region are extremely rare. A 45-year-old woman who presented with palpitations is reported. Electrocardiography revealed first-degree atrioventricular block. Echocardiography, computed tomography, and magnetic resonance imaging scans revealed a cystic mass attached to the interatrial septum. Complete surgical excision of the mass was achieved, although placement of a permanent pacemaker was required for complete heart blockage. Histopathological examination revealed the mass to be a cystic tumor of the atrioventricular nodal region. A 5-year follow-up has revealed no sign of recurrence.

Atrioventricular Node↗
PubMed2004

Effect of increased excursion of the ankle on the severity of acute eccentric contraction-induced strain injury in the gastrocnemius: an in vivo rat study.

BACKGROUND: Although muscle strain injury models are frequently employed, highly invasive procedures, including surgical intervention, are typically used to produce these models. In this study, a minimally invasive model of acute strain injury was produced with a single eccentric contraction. HYPOTHESIS: The authors tested whether the severity of strain injury in the in vivo gastrocnemius depends on the excursion of the ankle. STUDY DESIGN: Controlled laboratory study. METHODS: Animals were randomly assigned to 2 groups: a small range of motion group (90-105 degrees, n = 10) and a large range of motion group (90-125 degrees, n = 10). Tetanically activated gastrocnemius muscles with percutaneous electrical stimulation were simultaneously elongated by forced dorsiflexion of the ankle joint. RESULTS: Isometric tetanic force of the large range of motion group was significantly lower than the pretreatment control 1, 2, and 3 days after treatment. Such reduction was not observed in the small range of motion group. Apparent pathologic damage was observed in the large range of motion group throughout the study period of 10 days. CONCLUSIONS: A larger range of motion causes more damage in eccentric contraction by using the in vivo model. CLINICAL RELEVANCE: This in vivo model is useful to elucidate mechanisms of prevention and recovery of strain injury.

Animals↗
PubMed2004

Therapeutic angiogenesis by the controlled release of basic fibroblast growth factor for ischemic limb and heart injury: toward safety and minimal invasiveness.

We review our studies on therapeutic angiogenesis using basic fibroblast growth factor (bFGF) released in a controlled manner from biodegradable gelatin hydrogel (GH). The bFGF-GH was intramuscularly injected in rabbits with limb ischemia. The group treated with bFGF showed an increase in tissue blood flow under laser Doppler imaging and histology showed a greater vascular density compared with controls. Also, bFGF-GH was subepicardially injected into old heart infarcts in rats. In the group treated with bFGF, improved left ventricular function was shown by echocardiography and cardiac catheterization, increased regional blood flow in the peri-infarct area was detected by pinhole single-photon emission computed tomography using (201)Tl, and increased vascular density was demonstrated by histology. In rabbits with acute myocardial infarction, the heart was wrapped with the omentum (including the gastroepiploic artery) and a bFGF-GH sheet was applied. Postoperative assessment revealed rich communication from the gastroepiploic artery to the coronary artery and improved cardiac function. The controlled release of bFGF was effective for both limb and heart ischemia and is considered to be suitable for clinical use because its application in animals was feasible and safe with minimal invasiveness.

Angiography↗
PubMed2004

Accelerated graft disease in a composite saphenous vein with internal thoracic artery in a chronic renal dialysis patient.

A 59-year-old man with 18-year history of renal dialysis due to chronic nephritis suffered coronary artery disease, which was complete occlusion of the right coronary artery and diffuse 90% stenosis of the proximal left anterior descending artery. Off-pump coronary artery bypass grafting was performed. Saphenous vein (SV) was anastomosed with left internal thoracic artery (ITA) as a T-graft. Left ITA was anastomosed to the left anterior descending artery. The end of SV was sewn on the posterior descending artery. Coronary and graft angiography performed 2 weeks after the operation showed good patency with good distal run-off of both left ITA and SV. Three months after the operation, he was admitted with unstable angina. Angiography revealed accelerated SV graft stenosis without any change of prior coronary disease. However, angiography 7 months after the operation revealed complete obstruction of the SV graft when he was admitted because of recurrent anginal pain.

Angina Pectoris↗
PubMed2004

Rationale of off-pump coronary artery bypass grafting for left main trunk disease.

OBJECTIVE: Off-pump coronary artery bypass grafting (OPCAB) remains controversial in patients with left main trunk (LMT) disease because of a concern about the ability to tolerate hemodynamic instability. This study examined the safety of OPCAB for LMT disease compared with conventional coronary artery bypass grafting (CABG). METHODS: Between April 1997 and December 2002, 257 consecutive patients with LMT stenosis who underwent CABG were enrolled. There were 98 patients who received CABG with the aid of cardiopulmonary bypass (CCAB group), and 159 patients who received OPCAB (OPCAB group). RESULTS: There was no patient who converted to on-pump intraoperatively due to hemodynamic instability. Both intraoperative blood loss and blood transfusion incidence were lower in the OPCAB group. Postoperative course was similar, however, pulmonary complications were less observed postoperatively in the OPCAB group. No hypoperfusion syndrome was seen postoperatively in both groups. The average number of anastomosis was 3.2+/-1.1 in the CCAB group and 3.2+/-1.0 in the OPCAB group (p=0.645). Total arterial OPCAB with an aorta no-touch technique was achieved in 142 patients (89.3%) in OPCAB group. Postoperative angiography was performed in 95 patients in CCAB (96.9%), and in 141 patients in OPCAB (89.8%). Although graft patency of arterial grafts was good in both groups (100% in CCAB and 98.3% in OPCAB), saphenous vein graft patency was slightly lower in both groups (93.4% in CCAB and 76.5% in OPCAB) compared with arterial grafts. CONCLUSION: OPCAB allows a safe and effective treatment of LMT disease.

Aged↗
PubMed2004

Comparison of off-pump and on-pump coronary artery bypass grafting in midterm results.

OBJECTIVE: Off-pump coronary artery bypass grafting (OPCAB) has become a procedure of choice for surgical treatment of coronary artery disease. Although early advantages of OPCAB were confirmed in comparison with conventional on-pump coronary artery bypass grafting (CABG), late cardiac complications are still controversial. We examined midterm results of OPCAB compared with standard CABG. METHODS: Between July 1997 and April 2002, 736 consecutive patients who underwent isolated CABG were retrospectively reviewed. The OPCAB group (Group I) comprised 357 patients (49%), and the on-pump CABG group (Group II) 379 patients (51%). Their preoperative, intraoperative, and follow-up data were analyzed. RESULTS: The mean number of distal anastomoses and the early graft patency were not greatly different between the two groups. The actuarial survival rate at 3 years was not significantly different between Group I (98.3%) and Group II (98.2%) (p = 0.71). The frequency of cardiac events was 4.2%/patient-year in Group I and 2.6%/patient-year in Group II (p = 0.12). The actuarial event free rates were not different between the two groups (p = 0.61). The cardiac event free rates at 3 years were significantly (p = 0.011) higher in patients with complete revascularization (96.7%) than without complete revascularization in Group I (69.2%) and in Group II (92.7% versus 85.9%, p = 0.026). CONCLUSIONS: Midterm clinical outcome in OPCAB is as good as conventional on-pump CABG. Incomplete revascularization caused cardiac events more frequently than complete revascularization both in OPCAB and on-pump CABG in the intermediate follow-up.

Cardiopulmonary Bypass↗
PubMed2004

Rationale for off-pump coronary revascularization to small branches--angiographic study of 1,283 anastomoses in 408 patients.

BACKGROUND: Off-pump coronary artery bypass grafting (OPCAB) has gained wide acceptance in tandem with the development of the stabilizer and associated operative techniques. However bypass grafting to the small branches of a beating heart is technically demanding and remains controversial. In the present study we evaluated the graft patency and quality of anastomoses to small coronary arteries by early postoperative angiography. METHODS: Between March 2000 and December 2002 a total of 1,328 anastomosed sites to coronary branches were studied angiographically in 404 patients representing 88.6% of all cases who underwent OPCAB in this period. The coronary artery branches were categorized as large (>1.5 mm, group L: 1,028 anastomoses sites) or small (< 1.5 mm, group S: 300 sites) by intraoperative measurement. As in situ grafts the internal thoracic artery (ITA) and the gastroepiploic artery (GEA) were used at 504 and 28 distal anastomosis sites respectively. The radial artery (RA) was used as a composite graft for 739 distal anastomosis sites. Sequential bypass grafting was performed at 388 anastomosis sites in side-to-side fashion. Arterial grafts were used in 96.1% of total bypass grafting. RESULTS: The percentage of male gender was 78.3% in group S and 87.2% in group L (p = 0.025). The ITA was used in 43.7% of group L and 18.3% of group S (p < 0.0001). The RA was used in 49.4% of group L and 77% of group S (p < 0.0001). The overall patency and stenosis free rates (FitzGibbon Type A) were 97.2% and 96.2%. Graft patency and stenosis free rates in group S (96.7% and 93.3%) were as good as those in group L (97.5% and 97.1%). In group S, the patency and stenosis free rates of SV grafts were 71.4% and 57.1%. On the other hand, those of ITA grafts were 100% and 98.3% (p = 0.53 vs. saphenous vein graft [SVG]) and RA grafts were 95.8% and 92.1% (p = 0.61 vs. SVG) respectively. In group S, the graft patency and stenosis free rates of bypass to the obtuse marginal (OM) (93.7% and 87.5%) were slightly lower than those to other implantation sites left anterior descending (LAD: 100% and 97.3%; PL: 96.5% and 92.3%; DI: 98.0% and 96%; PDA: 97.0% and 97.0%; right coronary artery [RCA]: 100% and 100%) although there was no statistical significance. The graft patency and stenosis free rates were slightly better with side-to-side anastomosis than with end-to-side anastomosis (side-to-side: 98.1% and 95.8% vs. end-to-side 96.3% and 86.3%) in group S. CONCLUSIONS: OPCAB to small coronary artery branches with arterial grafts provided satisfactory graft patency and stenosis free rates.

Anastomosis, Surgical↗
PubMed2004

Competitive flow in arterial composite grafts and effect of graft arrangement in Off-Pump coronary revascularization.

BACKGROUND: We sought to investigate the incidence of competitive flow in arterial composite grafts and to delineate the effect of the location of moderately stenotic branch, the extent of the revascularized territories and the arrangement of in situ and free arterial grafts in off-pump coronary artery bypass grafting (OPCAB). METHODS: Three hundred eighteen patients who underwent OPCAB with aorta no-touch technique using the composite graft with totally arterial materials between December 2000 and March 2003 were studied. A total of 362 composite grafts were used. We reviewed their coronary angiography before and early after operation. Competitive flow was defined as the phenomenon that at least one of the distal anastomotic sites of the composite graft was not opacified in in situ graft angiography, but clearly opacified in native coronary angiography. The number of distal anastomoses was 3.47 +/- 0.93 per patient and 2.87 +/- 0.81 per composite graft. RESULTS: Early patency rate of the distal anastomotic sites of composite grafts was 98.7%. Competitive flow was found in 53/362 (14.6%) composite grafts, and graft occlusion occurred in 13/362 (3.6%) composite grafts. In the multivariate analysis of 362 composite grafts, 75% stenosis in right coronary artery (RCA) territory (p < 0.0001) and the number of distal anastomoses (p = 0.004) were significant predictors of competitive flow and graft occlusion. Multivariate analysis of 318 patients demonstrated that 75% stenosis in RCA territory (p < 0.0001) and the total number of distal anastomoses (p = 0.003) were statistically significant predictors of competitive flow and graft occlusion. The use of more than two in situ grafts and the shape of composite graft (branched or straight) did not have significant correlation with the outcome. CONCLUSIONS: Coronary artery revascularization using composite arterial grafts provided satisfactory early patency rates with an acceptable incidence of competitive flow. Because the implication of competitive flow in an arterial composite graft may differ from that in conventional bypass grafts unpredictably, long-term follow-up is mandatory.

Aged↗
PubMed2004

Total arterial off-pump coronary artery bypass grafting for revascularization of the total coronary system: clinical outcome and angiographic evaluation.

BACKGROUND: We assessed the clinical outcome and conducted an angiographic study of total arterial off-pump coronary artery bypass grafting for revascularization of the total coronary system. METHODS: Of 382 consecutive patients who underwent off-pump coronary artery bypass between April 2000 and December 2002, 235 patients (193 men and 42 women, mean age 66 +/- 9 years) with three-vessel disease underwent off-pump coronary artery bypass with all arterial grafts. A total of 872 vessels were bypassed (average number of grafts 3.7 +/- 0.8). The internal thoracic arteries, radial arteries, and gastroepiploic arteries were used for revascularization of 306, 542, and 24 coronary arteries, respectively. Two hundred twenty-five patients underwent revascularization with composite grafts that were connected to the in situ internal thoracic artery (Y configuration 181, I configuration 55, K configuration 27, X configuration 3, T configuration 1); 10 patients underwent revascularization with all in situ grafts. RESULTS: Three (1.3%) hospital deaths and 1 late death occurred. There were no occurrences of clinical underperfusion syndrome or new intraaortic balloon pump insertion. Cerebral infarction occurred in 2 patients (0.8%). Early postoperative angiography was performed on 833 grafts in 223 patients (95%); the overall patency rate was 98%. Stratified by coronary distribution, the patency rate was 99% (218/221) in the left anterior descending artery, 97% (84/87) in the diagonal artery, 99% (70/71) in the obtuse marginal artery, 98% (262/268) in the posterolateral artery, 98% (167/170) in the posterior descending artery, and 100% (16/16) in the right coronary artery. CONCLUSIONS: Total arterial off-pump coronary artery bypass yielded good clinical results and an excellent patency rate of revascularization for the total coronary system.

Adult↗
PubMed2004

Consequence of atrial fibrillation and the risk of embolism after percutaneous mitral commissurotomy: the necessity of the maze procedure.

BACKGROUND: We sought to investigate the incidence and risk of embolism after percutaneous balloon mitral commissurotomy (PMC) and delineated the necessity of the maze procedure in patients with atrial fibrillation (AF). METHODS: Clinical records of 326 patients, who underwent PMC between April 1988 and March 2003, and 162 patients, who underwent mitral valve surgery (MVS) combined with the maze procedure (MVS/maze) in the same period, were reviewed. We examined the consequence of cardiac rhythm and the incidence and risk of embolism after PMC. Next our current criteria for indication of the maze procedure, which included duration of AF less than 10 years, voltage of f wave on electrocardiography greater than 0.1 mV, cardiothoracic ratio less than 70%, and left atrial dimension less than 70 mm, were applied to all patients. These criteria were satisfied by 190 patients of PMC (PMC group) and 114 patients of MVS/maze (MVS/maze group) and the early and late results of the two groups were compared. RESULTS: Thirty-eight patients suffered from embolic complications after PMC. Of these 33 patients experienced AF before intervention. The actuarial embolism-free rate at 10 years was 81.9% in patients with AF before PMC and 92.9% in patients with sinus rhythm before PMC (p = 0.01). Univariate predictors of embolism after PMC included previous embolic history (p = 0.01), AF (p = 0.01), pressure gradient (p = 0.01), age (p = 0.03), and mitral valve area (p = 0.04). Multivariate analysis identified AF as the independent predictor of embolism in the late follow-up period (p = 0.03). In a comparative study of the selected patients the actuarial AF-free rates after MVS/maze were 89.9% at 1 year and 85.7% at 5 years and were significantly higher than those of 17.3% at 1 year and 4.2% at 5 years after PMC (p < 0.0001). The actuarial embolism-free rate in the MVS/maze group was 98.0% at 5 years and was significantly higher than that of 84.8% at 5 years and 82.4% at 10 years in the PMC group (p = 0.01). CONCLUSIONS: PMC alone is not sufficient with regard to sinus rhythm recovery and prevention of embolism. Surgical treatment concomitant with the maze procedure may be beneficial for patients with AF.

Atrial Fibrillation↗
PubMed2004

Modified cavoatriotomy for combined PAPVC repair and maze procedure.

In patients with partial anomalous pulmonary venous connection (PAPVC) to the superior cavoatrial junction, the standard right-sided left atriotomy does not allow sufficient access to the mitral valve and the left atrium. And the injury and traction of the sinus node and sinus node artery should be avoided for prevention of the cardiac rhythm disturbance after operation. We herein report a useful approach to repair the sinus venosus atrial septal defect with PAPVC of the right pulmonary veins to the superior cavoatrial junction in patients also requiring mitral valve replacement and the maze procedure.

Atrial Fibrillation↗
PubMed2004

Trunk muscle strength and disability level of low back pain in collegiate wrestlers.

INTRODUCTION/PURPOSE: Low back pain (LBP) is a frequent injury in athletes. This study examined the relationship between isokinetic trunk muscle strength and the functional disability level of chronic LBP. We particularly focused on the existence of radiological abnormalities (RA) in the lumbar region. METHODS: Subjects were 53 collegiate wrestlers. Trunk extensor and flexor muscle strength was measured at three angular velocities (60, 90, and 120degrees x s(-1)). The examined parameters for trunk muscle strength were peak torque, work, average torque, and average power. The disability level of LBP was estimated by using two questionnaires. Based on the RA evaluation with x-ray and MRI, all 53 wrestlers were assigned to two groups as the RA group (N = 35, 66%) and the non-RA group (N = 18, 34%). Correlations between trunk muscle strength and the disability level of LBP in each group were analyzed with Spearman's rank test. RESULTS: Without considering the disability level, there were 14 subjects with LBP (40%) in the RA group and 8 (44%) in the non-RA. Significantly correlated parameters with the disability level of LBP could be observed only when the subjects were restricted to the non-RA group. The correlated parameters with the two questionnaires were peak torque at 120degrees x s(-1), work at 60degrees x s(-1) and 90degrees x s(-1), and average torque at 90degrees x s(-1) and 120degrees x s(-1). There were no significantly correlated parameters in the RA group. None of the trunk flexor parameters were significantly correlated with the disability level of LBP. CONCLUSION: The relatively low strength of trunk extensors may be one of the factors related to nonspecific chronic low back pain in collegiate wrestlers.

Adolescent↗
PubMed2003

Identification of a consensus motif for Plk (Polo-like kinase) phosphorylation reveals Myt1 as a Plk1 substrate.

Plk1 (Polo-like kinase 1), an evolutionarily conserved serine/threonine kinase, is crucially involved in multiple events during the M phase. Here we have identified a consensus phosphorylation sequence for Plk1, by testing the ability of systematically mutated peptides derived from human Cdc25C to serve as a substrate for Plk1. The obtained results show that a hydrophobic amino acid at position +1 carboxyl-terminal of phosphorylated Ser/Thr and an acidic amino acid at position -2 are important for optimal phosphorylation by Plk1. We have then found that Myt1, an inhibitory kinase for MPF, has a number of putative phosphorylation sites for Plk1 in its COOH-terminal portion. While wild-type Myt1 (Myt1-WT) served as a good substrate for Plk1 in vitro, a mutant Myt1 (Myt1-4A), in which the four putative phosphorylation sites are replaced by alanines, did not. In nocodazole-treated cells, Myt1-WT, but not Myt1-4A, displayed its mobility shift in gel electrophoresis, due to phosphorylation. These results suggest that Plk1 phosphorylates Myt1 during M phase. Thus, this study identifies a novel substrate for Plk1 by determining a consensus phosphorylation sequence by Plk1.

Amino Acid Motifs↗
PubMed2003

Implantation of collar-reinforced sumit valve for patient with large calcified mass obstructing the mitral valve orifice.

A 56-year-old female had a severely calcified mitral valve annulus and a huge subvalvular mass. To avoid critical damages of the coronary artery and left ventricle, the annular calcification and the part of the mass adherent to the left ventricle were not resected. Then we performed mitral valve replacement using SuMit valve and collared reinforcement technique with xenopericardium without any major complications. The SuMit valve is designed to be placed in a supraannular position, and is useful to prevent valves from getting stuck.

Calcinosis↗
PubMed2003

Early results of complete off-pump coronary revascularization using left internal thoracic artery with composite radial artery.

OBJECTIVE: Off-pump coronary artery bypass (OPCAB) using the left internal thoracic artery (LITA) with a composite radial artery (RA) was employed for arterial revascularization in order to minimize neurological complication. METHODS: Sixty-one patients underwent OPCAB using the LITA with a composite RA. Angiography was performed in all patients at two weeks postoperatively. RESULTS: The mean number of distal anastomoses was 3.2 +/- 0.4. A Y-composite graft was used in 55 patients, and K-composite graft was used in the other 6 patients. There was no hospital death, no neurological complication nor deep sternal infection. Furthermore, there was no episode of perioperative myocardial infarction nor hypoperfusion syndrome. Patients have been angina-free during a mean follow-up period of 1 year. The graft patency of the LITA to the left anterior descending artery (LAD) was 100% (61/61 anastomoses). The RA became occluded in 4 patients, and the patency rate was 95.6% (130/136 anastomoses). String or coronary-coronary bypass resulting from flow competition was observed in the LITA of 6 patients and in the RA of 13 patients. The string of the LITA occurred in the segment distal from the anastomosis with the composite RA. The string or coronary-coronary bypass was observed more often in cases in which the recipient coronary artery had less than 75% stenosis. CONCLUSION: OPCAB using only the LITA with a composite RA can be successfully and safely performed in patients with multivessel disease. Late postoperative follow-up of the flow competition is necessary to delineate the significance of flow competition.

Aged↗
PubMed2003

Clinical usefulness of a new infrared videoendoscope system for diagnosis of early stage gastric cancer.

BACKGROUND: Infrared light can penetrate tissue more deeply than visible light. Therefore, an infrared video endoscope may be useful for assessment of gastric submucosal vessels. However, the resolution of currently available infrared video endoscope systems has been unsatisfactory. A new infrared video endoscope system was developed and its clinical utility assessed for diagnosis of early stage gastric cancer. METHODS: Twenty-five patients with early stage gastric cancer and 8 with gastric adenoma underwent endoscopy with the infrared video endoscope system after intravenous injection of indocyanine green. RESULT: Indocyanine green pooling did not appear in adenomas and some intramucosal gastric cancers, whereas it was noted in all submucosally invasive gastric cancers. Tumors not exhibiting indocyanine green pooling were intramucosal, well-differentiated adenocarcinomas of low height (flat-type cancers). CONCLUSION: These results suggest that our new infrared video endoscope provides valuable information about the submucosal aspect of early stage gastric cancer. Infrared video endoscopy may become a powerful technique for determining whether to perform endoscopic mucosal resection.

Adenoma↗