PubMed Health⌕ Search

Biomedical subjects

T Sakurabayashi

Publications and source records attributed to T Sakurabayashi.

9 recordsLinked to original sources
PubMed1999

Improvement of myocardial fatty acid metabolism through L-carnitine administration to chronic hemodialysis patients.

The concentration of carnitine, which is essential to fatty acid metabolism, can decrease markedly in patients on long-term hemodialysis coincident with life-threatening cardiac damage. However, administration of L-carnitine improves the myocardial function of these patients. To evaluate the underlying events of this phenomenon, we used recently developed technology, (123)I-labeled beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) myocardial scintigraphy, as a test of myocardial fatty acid metabolism. Our results showed that the free carnitine concentration (19.2 +/- 6.5 micromol/l) was lower in 11 chronically dialyzed patients than in 8 healthy controls (49.3 +/- 7.7 micromol/l, p < 0. 0001). Additionally the heart to mediastinal ratio (H/M) of BMIPP was higher for these patients than for the controls (1.91 +/- 0.19 vs. 1.52 +/- 0.24, p < 0.005), and the patients' washout rate (WOR) of BMIPP was lower (17.2 +/- 6.0 vs. 22.8 +/- 4.2%, p < 0.05). After L-carnitine was administered orally to the patients at doses of 1 g/day for 1 month and 0.5 g/day for the following month, the concentration of free carnitine in their sera increased to 85.4 +/- 27.0 micromol/l (p < 0.0001). Although the H/M ratio did not change (1.89 +/- 0.20) with this treatment, their WOR increased to 21.9 +/- 6.6% (p < 0.001), similar to that of controls. The left ventricular end-diastolic dimension and left ventricular fractional shortening remained unchanged, as shown by echocardiography. The results presented here denote that a carnitine deficiency in chronically hemodialyzed patients disrupts their myocardial fatty acid metabolism, which is improved by L-carnitine supplementation.

Carnitine↗
PubMed1999

Association between plasma homocysteine concentration and carotid atherosclerosis in hemodialysis patients.

Accelerated atherosclerosis is a major risk for uremic patients undergoing long-term hemodialysis. Because hyperhomocysteinemia may influence this condition, 168 such patients were examined for a possible association between plasma total homocysteine concentration (tHcy) and conventional cardiovascular risk factors. Generalized atherosclerosis was indicated by excessive intimal-medial wall thickness (IMT) of the extracranial carotid artery as measured by B-mode ultrasonography. The results documented tHcy in these patients of 33.0+/-16.9 micromol/L, a significantly higher amount than that of healthy subjects (11.0+/-3.1 micromol/L, p<0.0001). The patients' carotid maximum IMT was 1.79+/-1.16 mm. In multiple regression analyses with forward elimination procedure, carotid maximum IMT was clearly related to age (r = 0.417, p<0.0001), systolic blood pressure (r = 0.262, p = 0.0043), smoking (r = 0.177, p = 0.0076), duration of hemodialysis (r = 0.083, p = 0.0045), and tHcy (r = 0.195, p = 0.0021). These 5 factors accounted for 36.0% of the variation in carotid maximum IMT. Factors determined as unrelated were male gender, diastolic blood pressure, body mass index, total and HDL cholesterol, triglyceride, lipoprotein(a), uric acid, calcium, inorganic phosphate, and parathyroid hormone. Therefore hyperhomocysteinemia, along with advanced age, systolic hypertension and smoking aggravates atherosclerosis in chronic uremic patients.

Age Factors↗
PubMed1997

Switch from conventional to high-flux membrane reduces the risk of carpal tunnel syndrome and mortality of hemodialysis patients.

The use of a high-flux membrane, which eliminates larger molecular weight solutes with better biocompatibility, has steadily increased since the discovery of beta-2 microglobulin (beta 2m) amyloidosis in 1985. The long-term effects of a dialyzer membrane on morbidity and mortality are not completely understood. To examine the membrane effect as a factor of carpal tunnel syndrome onset and mortality, multivariate Cox regression analysis with time-dependent covariate was conducted on 819 patients from March 1968 to November 1994 at a single center. Two hundred and forty-eight of the patients were either switched from the conventional to high-flux membrane or treated only with a high-flux membrane. Fifty-one patients underwent a CTS operation and 206 died. Membrane status (on high-flux or on conventional) was considered as time-dependent covariate and risk was adjusted for age, gender, type of renal disease and calendar year of dialysis initiation. The relative risk of CTS was reduced to 0.503 (P < 0.05) and mortality 0.613 (P < 0.05) by dialysis on the high-flux membrane, compared to the conventional membrane. Serial measurements of beta 2m indicated significantly lower beta 2m to persist in patients on the high-flux membrane. The high-flux membrane decreased the risk of morbidity and mortality substantially. Larger molecule elimination was shown important not only for preventing beta 2m amyloidosis, but for prolonging survival of dialysis patients as well.

Adult↗
PubMed1994

Primary directional coronary atherectomy for acute myocardial infarction.

The effectiveness of primary coronary angioplasty for acute myocardial infarction (AMI) is now widely recognized. However, the reocclusion rate is as high as 10%. Directional coronary atherectomy (DCA), now used widely in the treatment of stable and unstable angina pectoris, has not been recommended as the primary reperfusion therapy for AMI. This report describes the first preliminary study of primary DCA for AMI without any antecedent thrombolytic therapy or balloon coronary angioplasty. Five patients received primary DCA. The initial results were very good, but further study is necessary to determine the efficacy, particularly the long-term results, of primary DCA in the treatment of AMI.

Atherectomy, Coronary↗
PubMed1993

[Time-sequential changes of vagal activity with aging].

We examined the correlation of the time-sequential variability of vagal activity with the heart, and then the circadian rhythm of vagal activity and its changes with aging were investigated. The subjects consisted of 154 healthy volunteers, 90 males and 64 females whose ages ranged from 12 to 83 years. Holter monitoring was performed continuously for 24 hours. RR interval and RR50 were measured using Ewing's method. Least square-fit of a cosine curve in a period of 24 hours of these parameters was calculated, and MESOR (midline estimating statistic of rhythm), amplitude and acrophase were determined. The results were as follows: 1. In all subjects, the circadian rhythms of the RR interval were significantly noted. MESOR, amplitude and acrophase of the RR interval were 0.83 +/- 0.07 sec (mean +/- SD), 0.16 +/- 0.06 sec and 19.6 +/- 33.8 degrees. MESOR and acrophase were not changed significantly by aging. Amplitude was significantly decreased by aging (r = -0.23, p < 0.01). 2. The circadian rhythm of RR50 was dominantly and significantly noted in 92 of 154 cases. MESOR of RR50 were 477 +/- 301 counts/hr and the amplitudes of RR50 were 319 +/- 209 counts/hr. These indices were significantly changed by aging (MESOR: r = -0.69, p < 0.01; amplitude: r = -0.51, p < 0.01). 3. Acrophase of RR50 was 30.0 +/- 47.8 degrees, and it became delayed by aging (r = 0.32, p < 0.01). In conclusion, 1) based on the cosinor analysis of time sequential changes of RR50, the circadian rhythm of cardiac vagal activity was validated. 2) Heart rate is determined chiefly by the intrinsic heart rate and the autonomic nervous system. At rest vagal activity to heart rate is dominant over sympathetic activity, and the intrinsic heart rate decreases by aging. So the fact that MESOR of RR interval was not changed by aging and that MESOR of RR50 decreased by aging indicated that vagal activity to the heart decreased with aging. 3) Vagal activity accelerated during the time between midnight and early morning.

Adolescent↗