Search PubMed⌕ Search

Biomedical subjects

T Nakata

Publications and source records attributed to T Nakata.

At least 37 records · Page 2Linked to original sources
PubMed2001

Cardiac surgery in patients with end-stage renal disease. Utility of continuous ambulatory peritoneal dialysis.

OBJECTIVES: The number of patients with end-stage renal disease undergoing open heart surgery continues to grow. We evaluated continuous ambulatory peritoneal dialysis and the extracorporeal ultrafiltration method during cardiopulmonary bypass in the management of these difficult patients. METHODS: These 2 methods were used in 4 patients with renal failure who underwent open heart surgery between July 1997 and March 1999. Preoperative continuous ambulatory peritoneal dialysis was conducted using standard protocols. Extracorporeal ultrafiltration method was used only during cardiopulmonary bypass. Continuous ambulatory peritoneal dialysis was initiated upon arrival at the intensive care unit. Mean follow-up was 12 months. RESULTS: Postoperative blood urea nitrogen and creatinine concentrations were lower than preoperative concentrations. No patients required hemodialysis. All 4 patients were discharged to their homes. No deaths occurred. CONCLUSIONS: Continuous ambulatory peritoneal dialysis and extracorporeal ultrafiltration method are combined to treat patients with end-stage renal disease who require open heart surgery. This combination is simple, and does not require specialized personnel, and obviates the hemodynamic instability associated with hemodialysis.

Aged↗
PubMed2001

Reduction of white coat effect by cilnidipine in essential hypertension.

Stress elevates blood pressure (BP) by increased sympathetic nerve activity. Cilnidipine, a novel dihydropyridine calcium antagonist that has inhibitory actions on N-type as well as L-type voltage-dependent calcium channels, has been reported to attenuate the cold stress-induced increase in plasma norepinephrine and BP in rats. Because white coat effect is associated with an enhanced pressor response to mental stress, we postulated that cilnidipine would attenuate white coat effect in patients with essential hypertension. Sixty-one consecutive outpatients (50 men, 11 women) with essential hypertension were studied prospectively. Twenty-nine patients were treated with either cilnidipine (n = 15) or nifedipine, a representative L-type voltage-dependent calcium antagonist (n = 14). Gender, age, body mass index, duration of hypertension, target organ damage of hypertension, and BP and heart rate (HR) were not significantly different between cilnidipine and nifedipine groups, and both systolic (SBP) and diastolic BP (DBP) were significantly decreased after treatment in both groups. White coat effects on systolic and DBP and HR were not significantly different between groups before antihypertensive treatment. Cilnidipine, but not nifedipine, significantly reduced white coat effects on SBP and HR. Furthermore, white coat effects on systolic BP and HR were significantly lower after treatment in the cilnidipine group compared with the nifedipine group. These data suggest that cilnidipine may reduce white coat effect in hypertensive patients by N-type calcium channel antagonism.

Blood Pressure↗
PubMed2001

Studies on the prevalence of complicated atrial arrhythmias, flutter, and fibrillation in patients with reciprocating supraventricular tachycardia before and after successful catheter ablation.

Atrial flutter and AF are complications in approximately 30% of cases of paroxysmal supraventricular tachycardia (PSVT)-indicated catheter ablation, and it is of interest to determine if therapeutic modification for PSVT would eliminate combined atrial tachyarrhythmia like atrial flutter and AF. The aim of this study was to determine the incidence and the risk of atrial tachyarrhythmias after catheter ablation of PSVT. A total of 152 patients (age range 12-74, mean 41 +/- 17 years) with accessory pathway (n = 106) and/or dual atrioventricular nodal conduction (n = 46) were enrolled in a 2-year follow-up program after successful catheter ablation. Possible risks on clinical background (age, sex, PSVT duration, hemodynamic instability during attacks), premature atrial contraction (PACs) on Holter monitoring, echocardiographic left atrial size, and electrophysiological property (insertion site, conduction type, effective refractory period) were evaluated. Atrial flutter and AF were complications in 53 (35%) of the subjects, who were elderly and had a longer PSVT history with a larger left atrial dimension and frequent PACs; however, the electrophysiological properties were similar. After a 2-year follow-up period 36 (24%) of the patients still exhibited PAC runs, including 13 (9%) with atrial flutter and AF, each one of whom were complicated with nonlethal cerebral thromboembolism and congestive heart failure. Multiplelogistic-regression analysis revealed that advanced age (> or = 41 years, P = 0.0152) and frequent PACs (> or = 1% of total daily QRS counts, P = 0.0426) on Holter monitoring are the risk factors of PAC runs and/or atrial flutter and AF. In conclusion, successful ablation for PSVT is thought to be beneficial for preventing atrial flutter and AF. However, careful follow-up to monitor for the recurrence and atrial flutter and AF related complications, especially in patients of solitary atrial flutter and AF without reciprocating tachycardia and with frequent PAC.

Adolescent↗
PubMed2001

Antiinflammatory effect of heparin-coated circuits with leukocyte-depleting filters in coronary bypass surgery.

Cardiac surgery with cardiopulmonary bypass is associated with a systemic inflammatory response. We examined combined use of heparin coating of the cardiopulmonary bypass circuit and a leukocyte-depleting arterial line filter to reduce this response. Thirty patients were allocated randomly to equal groups with a conventional circuit and arterial line filter (C group), a heparin-coated circuit with a conventional filter (H group), or a heparin-coated circuit with a leukocyte-depleting arterial line filter (HF group). Cytokines and respiratory function were repeatedly measured perioperatively. Plasma interleukin (IL)-6 concentrations in the HF group were lower than in the C group immediately following bypass and operation, at 4 h, and 12 h (p < 0.05). Plasma IL-8 was lower in the HF group than in the C group at 4 h (p < 0.05). The respiratory index was lower immediately after bypass in the HF group than the C group (0.61 +/- 0.2 versus 1.05 +/- 0.4, p < 0.05). Heparin-coated circuits with leukocyte-depleting filters decrease inflammatory responses and improve pulmonary function during operation.

Adult↗
PubMed2001

CD2- CD4+ CD56+ hematodermic/hematolymphoid malignancy.

BACKGROUND: CD2- CD4+ CD56+ lymphoid malignancy has been only rarely reported the last 5 years. It is characterized by a high incidence of cutaneous involvement, cytologically agranular cells, aggressive clinical course, and negative Epstein-Barr virus (EBV) involvement. OBSERVATION: We describe a Japanese patient with a unique hematolymphoid malignancy characterized by an involvement of skin, nasopharyngeal region, bone marrow, lymph node, and a CD4+ CD43+ CD56+ CD2- CD3- CD8- and terminal deoxynucleotidyl transferase phenotype. Clinically, the cutaneous eruptions were purplish, hard, multiple nodules. Histologically, a massive proliferation of atypical pleomorphic cells with medium-sized nuclei were observed throughout the dermis. No clonal rearrangement of T-cell receptor (TCR)-beta gene or immunoglobulin heavy chain J gene was found, and no positive identification of EBV by in situ hybridization for EBV-encoded small nuclear RNA was found. The patient underwent high-dose chemotherapy with autografting of peripheral blood stem cells; however, the tumors quickly relapsed. CONCLUSION: We gathered data from 17 cases of lymphoid malignancy from the literature sharing immunophenotypic and genotypic features similar to those of our case, including CD2- CD4+ CD56+ and germline rearrangement of TCR. Although the cellular origin could not be decided, this malignancy was found to have 100% affinity for skin, a short course, and poor prognosis.

CD2 Antigens↗
PubMed2001

Unusual coronary artery aneurysm and acute myocardial infarction in a middle-aged man with systemic lupus erythematosus.

A 55-year-old man developed acute myocardial infarction (AMI) related to a large coronary artery aneurysm and a distal coronary stenotic lesion after steroid therapy for systemic lupus erythematosus (SLE). Only 13 SLE patients with AMI caused by coronary artery aneurysms have been reported, 11 of whom were young or middle-aged women and the 2 remaining were young men. This is the first report of a middle-aged man with multiple coronary lesions.

Arteriosclerosis↗
PubMed2001

Quantification of limited augmentation of myocardial (99m)Tc-tetrofosmin uptake at exercise in stable coronary artery disease.

We evaluated the diagnostic accuracy of a new method for quantitative analysis of myocardial perfusion at exercise using (99m)Tc-tetrofosmin tomographic imaging. (99m)Tc-tetrofosmin imaging of an exercise-rest sequence was performed in 30 patients with coronary artery disease (CAD) and eight age-matched control subjects. The exercise-induced myocardial count increase was calculated as the relative value (per cent increase ratio, %IR) to that at rest by correcting for physical decay for (99m)Tc and injected doses and by a subtraction technique. Exercise and rest (99m)Tc-tetrofosmin images were assessed visually and quantitatively using the per cent peak count and %IR of the myocardial count at exercise. Segments with significant coronary stenosis (diameter stenosis=75% or more) showed a significantly lower %IR than did those without significant coronary stenosis in the CAD patients (37+/-19% vs 63+/-21%, P<0.05). The diagnostic efficacy of visual analysis for detecting coronary stenosis was as follows: sensitivity, 58.1% and specificity, 81.4%. When %IR=37% was used for detecting significant coronary stenosis, sensitivity and specificity increased to 74.2% and 93.2%, respectively. Furthermore, the quantitative analysis significantly (P=0.04) improved the overall diagnostic accuracy from 73.3% to 86.7% compared to that of visual assessment. Thus, augmentation of myocardial (99m)Tc-tetrofosmin uptake at exercise is blunted in the myocardium with significant coronary stenosis. The calculation of myocardial count increase at exercise relative to that at rest can improve the diagnostic value of (99m)Tc-tetrofosmin SPECT imaging and may contribute to more accurate quantification of myocardial ischaemia and impaired tracer uptake in coronary artery disease.

Adult↗
PubMed2001

Role of the central nervous system in the development of hypertension produced by chronic nitric oxide blockade in rats.

We examined the role of the central nervous system, and particularly the renin-angiotensin (RA) system, in the development of hypertension produced by chronic inhibition of NO synthesis. In experiment 1, Wistar rats drank either nitro-L-arginine-methyl ester (L-NAME) or tap water. Before L-NAME treatment rats were divided into 6 groups. Four of them were administered either losartan or artificial cerebroventricular fluid (a-CSF) intracerebroventricularly (i.c.v.) for 1 week using an osmotic mini pump. The other two groups were administered the same amount of losartan intravenously (i.v.). In experiment 2, cardiovascular responses to acute i.c.v. losartan and muscimol, a GABA(A) agonist, were examined in conscious L-NAME-treated rats. Finally, in experiment 3, effects of ablation of the AV3V (anteroventral third ventricle) area, known to be one of the centers of cardiovascular control, were tested in the development of L-NAME hypertension. The development of hypertension by L-NAME treatment was attenuated with chronic i.c.v. losartan in a dose-dependent manner, while i.v. losartan had no effect. One week after cessation of i.c.v. losartan, blood pressure was elevated to the same level as in a-CSF-infused, L-NAME-treated rats. Acute i.c.v. losartan produced no cardiovascular changes in either L-NAME-treated or control rats. On the other hand, although i.c.v. muscimol elicited depressor effects in both groups, these responses were significantly larger in L-NAME-treated rats. Cardiovascular responses to i.v. hexamethonium were similar in both groups. The existence of prior lesions in the AV3V area significantly attenuated the development of L-NAME-induced hypertension. These results indicate that the central RA system plays an important role in the development of hypertension produced by chronic inhibition of NO synthase. Moreover, disorder of the central GABA system, rather than that of the RA system, might be important in the maintenance of hypertension in this model.

Animals↗
PubMed2001

Impaired exercise-related myocardial uptake of technetium-99m-tetrofosmin in relation to coronary narrowing and diabetic state: assessment with quantitative single photon emission computed tomography.

Despite the diagnostic efficacy of stress myocardial perfusion imaging, the correlation between the actual perfusion tracer activity and diseased state of a coronary artery has not been studied in detail. We estimated exercise-related perfusion augmentation in relation to disease states of a coronary artery in diabetic and non-diabetic patients by a newly developed quantitative technetium (Tc)-99m-tetrofosmin myocardial imaging technique. Tc-99m-tetrofosmin tomographic imaging with an exercise-rest protocol was performed in 26 stable coronary patients and in 8 age-matched controls. Percent increase (%IR) in myocardial count during symptom-limited submaximal exercise-stress was calculated in 16 non-infarcted polar map segments and in each coronary territory by a subtraction technique with corrections for physical decay and injected tracer doses, and the results were compared with those of angiographically quantified coronary diameter stenosis (%DS). Percent IR and peak heart rate during exercise showed a positive linear correlation both in coronary territories with significant stenosis (%DS > or = 75%) and in control or nonstenotic (%DS < 75%) territories. The regression line in stenotic regions was, however. significantly (p < 0.01) shifted downward compared to that in non-stenotic regions. Percent IR in stenotic regions showed a significant inverse correlation with %DS. Coronary stenosis of 75% or more was identified by a %IR cutoff value of 40% with 77% sensitivity, 70% specificity, and an accuracy of 72%. In coronary territories with a %DS of less than 75%, %IR in diabetic patients was significantly lower (46+/-15%) than that in nondiabetic patients (61+/-25%). Thus, blunted exercise-related augmentation of myocardial uptake of Tc-99m-tetrofosmin correlates with the severity of coronary narrowing and diabetic state.

Adult↗
PubMed2001

Crow-Fukase syndrome with ischemic cardiomyopathy.

A 31-year-old man was admitted to our hospital for further evaluation of heart failure symptoms. Crow-Fukase syndrome was diagnosed on the basis of findings of polyneuropathy, hepatomegaly, monoclonal hypergammaglobulinemia, and hypertrichosis. Dipyridamole-stress thallium-201 perfusion imaging, contrast left ventriculography, and coronary angiography revealed a markedly dilated and dysfunctioning left ventricle, extensive reversible ischemia with fixed defect, and multiple coronary lesions. Histopathology of myocardial biopsy specimens demonstrated ischemia-induced myocardial necrosis. These findings suggested that ischemic cardiomyopathy, probably due to inflammatory reactions of coronary arteries in Crow-Fukase syndrome, was responsible for the heart failure symptoms and left ventricular dysfunction in this patient.

Adult↗
PubMed2001

[Usefulness of right ventricular Doppler index for predicting outcome in patients with dilated cardiomyopathy].

OBJECTIVES: Left ventricular Doppler index (LVDI) is believed to be a useful echocardiographic index of systolic and diastolic ventricular function. However, the usefulness of right ventricular Doppler index (RVDI) remains uncertain, especially in dilated cardiomyopathy. The predictive value of RVDI for estimating long-term cardiac events, including cardiac death, was investigated. METHODS: Fifty-nine consecutive patients with dilated cardiomyopathy (41 males and 18 females, mean age 52 +/- 15 years) were enrolled in this follow-up study. RVDI and LVDI were calculated as follows: DI = (isovolumic contraction time + isovolumic relaxation time)/ejection time. RESULTS: During a follow-up period of 3.7 +/- 3.0 years, 27 (46%) of the patients exhibited cardiac events, including cardiac death (n = 9), heart failure (n = 16) and tachyarrhythmias (n = 2) requiring in-hospital treatment. Patients with these cardiac events had higher LVDI and RVDI at the initial follow-up examination, and RVDI had a significant linear correlation with LVDI (LVDI = 0.550 + 0.452 x RVDI, r = 0.530, p = 0.0001). The 6-year survival rate was significantly lower in patients with both LVDI > or = 0.78 and RVDI > or = 0.49 than in other patients (50% vs 75%, respectively, p = 0.009). Cox proportional hazards model analysis showed that RVDI > or = 0.49 was the independent predictor of cardiac events (p = 0.0153) and cardiac death (p = 0.0003). CONCLUSIONS: RVDI is clinically useful for estimating the outcome of patients with dilated cardiomyopathy.

Adult↗
PubMed2001

Effect of coronary artery bypass grafting on native coronary artery stenosis. Comparison of internal thoracic artery and saphenous vein grafts.

BACKGROUND: The purpose of this study was to investigate the influence of coronary artery bypass grafting on the degree of stenosis of the native coronary artery. METHODS EXPERIMENTAL DESIGN: retrospective data analysis. SETTING: University hospital. PATIENTS: consecutive patients undergoing coronary artery bypass grafting (n=52). Bypasses using internal thoracic artery grafts (n=26) and saphenous vein grafts (n=37) to incompletely occluded coronary arteries were studied. INTERVENTIONS: coronary artery bypass grafting using internal thoracic artery or saphenous vein grafts. MEASURES: stenosis of the native coronary artery on angiography. RESULTS: Three recipient coronary arteries bypassed with internal thoracic artery grafts (12%) and 14 recipient coronary arteries bypassed with saphenous vein grafts (38%) showed progression of narrowing (p=0.024). Two recipient coronary arteries bypassed with internal thoracic artery grafts (8%) and 13 recipient coronary arteries bypassed with saphenous vein grafts (35%) showed total occlusion (p=0.016). Hypertension, hyperlipidemia, diabetes mellitus, and smoking history did not correlate with progression of stenosis of the native coronary arteries. Graft flow measured during surgery in the saphenous vein grafts was not significantly different between the group that exhibited progression of the native stenosis and the group that did not. CONCLUSIONS: Coronary artery bypass grafting with saphenous vein grafts may result in progression of stenosis of the recipient coronary artery. This is less likely after coronary artery bypass grafting with internal thoracic artery grafts. This difference may be due to the ability of the pedicled internal thoracic artery graft to regulate flow. Thus competitive flow in the native coronary artery is minimized. This has significant clinical implications.

Aged↗
PubMed2001

Defect in human myocardial long-chain fatty acid uptake is caused by FAT/CD36 mutations.

Because of the importance of long-chain fatty acids (LCFAs) as a myocardial energy substrate, myocardial LCFA metabolism has been of particular interest for the understanding of cardiac pathophysiology. Recently, by using radiolabeled LCFA analogues, myocardial LCFA metabolism has been clinically evaluated, which revealed a total defect of myocardial LCFA accumulation in a small number of subjects. The mechanism for the cellular LCFA uptake process is still disputable, but recent results suggest that fatty acid translocase (FAT)/CD36 is a transporter in the heart. In the present study, we analyzed mutations and protein expression of the FAT/CD36 gene in 47 patients who showed total lack of the accumulation of a radiolabeled LCFA analogue in the heart. All the patients carried two mutations in the FAT/CD36 gene, and expression of the FAT/CD36 protein was not detected on either platelet or monocyte membranes. Our results showed the link between mutations of the FAT/CD36 gene and a defect in the accumulation of LCFAs in the human heart.

Adolescent↗
PubMed2001

[Evaluation of a combination chemotherapy with nedaplatin and 5-FU for oral cancers].

Nedaplatin (cis-diammine-glycolato platinum: CDGP) is a platinum compound with a molecular weight of 303.18 that was recently developed in Japan. There have been reports of the antineoplastic effects of Nedaplatin on cancers in the cranio-cervical region, lung, esophagus, urinary bladder, testis, ovary, and uterus. In this study, we performed combined therapy of CDGP and fluorouracil (5-FU) for 8 patients with oral cancers, and evaluated the results to elucidate the clinical effect and adverse side effects. The subjects were 8 patients with squamous cell carcinoma (5 males and 3 females aged 33-65 years). The primary carcinoma regions were the tongue in 5 patients, oral floor in 2 patients, and mandibular gingiva in 1 patient. The T-classification was T2 in 6 patients and T4 in 2 patients, and the clinical staging was Stage II in 5 patients, Stage III in 1 patient and Stage IV in 2 patients. We first administered 700 mg/m2 5-FU per day from day 1 to day 5 (total dose 3,500 mg/m2), then 90 mg/m2 CDGP on day 5. The clinical effect was evaluated as a partial response in all cases, showing a 100% success rate. The histopathological findings of resected tumors were evaluated by Ohboshi and Shimozato's classification. One patient was Grade IIA, 5 patients Grade IIB, and 2 patients Grade III. The adverse side effects were slight myelotoxicity, gagging, nausea, alopecia, and stomatitis less than Grade II. Although the oral cancers in this study were extroverted superficial ulcerative cancers, and the number of patients was low at 8, this combined therapy is considered useful and worth evaluating in further accumulated cases.

Adult↗
PubMed2001

[Clinical application of gated SPECT imaging to regional function assessment: current status and limitations].

It is likely that clinical applications of ECG-gated single-photon emission computed tomography (SPECT) are established in nuclear cardiology practice because of the improved diagnostic accuracy of gated SPECT imaging for the detection of coronary artery disease and because this technique enables not only simultaneous assessment of myocardial perfusion and function but also improvement of risk stratification of coronary patients. Although a gated approach with SPECT imaging has been demonstrated to have high reproducibility and reliability for quantifying global function, there are several limitations in appropriate processing of 4-dimensional data for quantitative assessment of regional function. Even if limited spatial and temporal resolutions and a lack of attenuation and scatter corrections are disregarded, sufficient data collection, image-quality control, and precise application of algorithms to gated SPECT data are prerequisite. The results of several kinds of quantitative analysis of regional cardiac function, such as regional wall motion (distance deviation of the inner myocardial border), regional ejection fraction, percent wall thickening, and percent count increase with or without self-normalization have been reported. Further clinical application of quantitative regional function assessment by a gated SPECT technique, however, requires standardization of data acquisition, data analysis, and data presentation with appropriate quantitative parameters; production of a standard map using quantitative values; and validation study by comparison with results of visual analysis and other modalities in a large-scale patient population.

Algorithms↗
PubMed2001

[Blood transfusion under cardiopulmonary bypass is a possible inducer for inflammation?].

To investigate that blood transfusion under cardiopulmonary bypass is a possible inducer for inflammation, a retrospective study was made with 20 adult patients who underwent coronary artery bypass grafting. The subjects were divided into two groups; transfusion group (group T) including 9 patients who received blood transfusion during cardiopulmonary bypass and the control group (group C) including 11 patients who did not undergo perioperative transfusion. Respiratory index as an indicator of respiratory functions was determined before and immediately after cardiopulmonary bypass, at the end of surgery and 4 hours thereafter. Cardiac index and arterial pressure were determined as the indicator of cardiac function. Moreover, interleukin 6 and 8 (IL-6 and IL-8), inflammatory cytokines were measured and compared between the two groups. The mean amount of blood transfusion was 2.1 units per individual of group T. The minimum value of hematocrit during cardiopulmonary bypass was significantly lower in group T (15.8 +/- 1.8%) than group C (19.1 +/- 1.4%), but the difference became not significant after cardiopulmonary bypass. There were no significant differences either in aortic pressure or cardiac index between two groups. The respiratory index at the end of surgery was higher in group T but the difference was not significant. Meanwhile IL-8 level at the end of cardiopulmonary bypass was significantly higher in group T (67.9 +/- 36 pg/ml) than group C (35.1 +/- 21 pg/ml). However, there was no difference in IL-6 level between the two. These results suggested that inflammation might be aggravated by an increase of IL-8 induced by blood transfusion.

Aged↗