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Biomedical subjects

K Sakamoto

Publications and source records attributed to K Sakamoto.

At least 433 records · Page 24Linked to original sources
PubMed1995

Non-destructive elemental analysis of vertebral body trabecular bone using muonic X-rays.

Non-destructive elemental analysis with muonic X-rays was performed on human vertebral bone and lumbar torso phantoms. It can provide quantitative information on all elements in small deep-seated localized volumes. The experiment was carried out using the superconducting muon channel at TRIUMF in Vancouver, Canada and a lithium drifted germanium detector with an active area of 18.5 cm2. The muon channel produced backward-decayed negative muons with wide kinetic energy range from 0.5 to 54.2 MeV. The muon beam was collimated to a diameter of 18 mm. The number of incoming muons was about 4 x 10(6) approximately 5 x 10(7) per data point. In the measurements with human vertebral bones fixed with neutralized formaldehyde, the correlation coefficient between calcium content measured by muons and by atomic absorption analysis was 0.99 and the level of significance was 0.0003. In the measurements with lumbar torso phantoms, the correlation coefficient between calcium content measured by muons and by atomic absorption analysis was 0.99 and the level of significance was 0.02. The results suggest that elemental analysis in vertebral body trabecular bone using muonic X-rays closely correlates with measurements by atomic absorption analysis.

Adolescent↗
PubMed1995

Enhanced replication of orbiviruses in bovine testicle cells infected with bovine viral diarrhoea virus.

Bovine testicle (BT) cells infected with non-cytopathogenic (NCP) bovine viral diarrhoea virus (BVDV) developed cytopathogenic effect (CPE) after superinfection with 7 Orbiviruses, whereas no CPE was induced by them in the absence of NCP BVDV infection. The CPE was accompanied by the enhanced replication of Orbiviruses. Seven of 10 strains of NCP BVDV induced the enhanced replication of Ibaraki virus, a member of Orbivirus. These 7 strains of NCP BVDV were END phenomenon positive. In contrast, the absence of CPE and the suppression of growth of Ibaraki virus were seen in BT cells infected with the other 3 strains which were END phenomenon negative. The END phenomenon negative viruses were different markedly from the END phenomenon positive viruses with respect to interactions with Orbivirus. The mechanism of the enhanced replication of Orbivirus seems to be explained with the suppression by the END phenomenon positive NCP BVDV to the interferon production of Orbivirus in BT cells.

Animals↗
PubMed1995

Expression of mRNA encoding the prostaglandin F2 alpha receptor in bovine corpora lutea throughout the oestrous cycle and pregnancy.

The abundance of mRNA encoding the PGF2 alpha receptor in bovine corpora lutea at different phases of the oestrous cycle and pregnancy was examined in relation to the number of [3H]PGF2 alpha binding sites. Corpora lutea were removed from cyclic (early: 3-5 days after ovulation; mid-cycle: 8-12 days after ovulation; late: 15-18 days after ovulation; and regressed: 20-21 days after ovulation) and pregnant (early: fetal size 9-13 cm (2-3 months); mid-cycle: fetal size 42-43 cm (5-6 months); and late: fetal size 78-80 cm (8 months)) cows and subjected to total RNA preparation, in situ hybridization and membrane preparation for [3H]PGF2 alpha binding assay. Northern blot analysis demonstrated that expression of PGF2 alpha receptor mRNA progressively increased from the early phase to the late phase of the oestrous cycle, and was markedly reduced at the regressed phase; while constant amounts of mRNA were observed in early and middle pregnant corpora lutea, and there was a significant reduction at late pregnancy. Specific high affinity [3H]PGF2 alpha binding sites with Kd values of 18.3-31.1 nmol-1 were observed in the luteal membrane during the oestrous cycle and pregnancy; this is consistent with the expression of PGF2 alpha receptor mRNA. The number of receptors decreased at the regressed phase and in early pregnancy. These results strongly suggest that PGF2 alpha is involved in not only luteolysis but also luteal functions in both pregnant and nonpregnant cows.

Animals↗
PubMed1995

Effects of L- and DL-carnitine on patients with impaired exercise tolerance.

We designed this study to determine whether orally administered L- and DL-carnitine can improve exercise tolerance in a group of patients with exercise intolerance. Nineteen patients with cardiac disease were randomly divided into 2 groups, an L-carnitine treatment group (n = 9) and a DL-carnitine treatment group (n = 10). Eight additional age-matched patients served as an untreated control group. Subjects in both carnitine treatment groups underwent cardiopulmonary exercise testing on a cycle ergometer in order to determine peak exercise time, peak oxygen uptake (VO2), lactate threshold (LT) and ventilatory threshold (VT) before and after the oral administration of 900 mg/day of L- or DL-carnitine for 2 weeks. Basal values of peak exercise time, peak VO2, LT and VT did not differ significantly among the 3 groups. Peak exercise time and peak VO2 tended to be increased in the L-carnitine treatment group, and tended to be decreased in the DL-carnitine treatment group. Both LT and VT (ml/kg/min) were significantly improved (LT: from 9.7 +/- 0.6 to 10.8 +/- 1.0, p < 0.05; VT: from 9.8 +/- 0.8 to 11.8 +/- 1.9, p < 0.02) by the administration of L-carnitine, while LT was significantly decreased (from 11.0 +/- 2.0 to 9.6 +/- 1.2, p < 0.05) and VT tended to be decreased by the administration of DL-carnitine (from 11.6 +/- 2.0 to 10.8 +/- 2.4). In the untreated control group, no significant changes were observed in the values of exercise tolerance between the 2 series of exercise testings. In neither group did carnitine modify hemodynamic parameters at rest or during exercise. In conclusion, this study demonstrated that L-carnitine increases and DL-carnitine decreases exercise tolerance in patients with impaired exercise tolerance.

Administration, Oral↗
PubMed1995

Exercise-induced rise in arterial potassium is enhanced in patients with impaired exercise tolerance.

We assessed the changes in arterial potassium concentration during exercise and recovery in relation to exercise tolerance in patients with impaired exercise tolerance. Sixteen patients with cardiac disease were subjected to a cardiopulmonary exercise test on a cycle ergometer. Arterial potassium and lactate concentrations were measured every minute during and after exercise, and ventilatory threshold (VT) and lactate threshold (LT) were identified. Before exercise, arterial potassium concentration was 3.8 +/- 0.3 mEq/l. It increased to 4.1 +/- 0.3 mEq/l at LT (p < 0.002 versus at rest), to 4.2 +/- 0.3 mEq/l at VT, and to 4.8 +/- 0.5 mEq/l at peak exercise (p < 0.001 versus at LT, p < 0.001 versus at VT). At an exercise intensity equivalent to 30, 40, 50 or 60% of predicted maximum oxygen uptake, the increase in arterial potassium showed a negative and significant correlation with %LT (r = -0.62 approximately -0.72, p < 0.01 approximately 0.05) and %VT (r = -0.62 approximately -0.75, p < 0.001 approximately 0.05), where %LT and %VT represent the ratios of LT and VT to the predicted maximum oxygen uptake, respectively. There was a good correlation between the rate of fall in potassium concentration during recovery and its increase during exercise. It was concluded that in patients with impaired exercise tolerance, the greater the degree of exercise intolerance, the greater the increase in arterial potassium concentration during exercise, and the steeper the fall in potassium concentration during recovery. Because the rise in potassium concentration during exercise and its fall during recovery were greater when the exercise level exceeded the anaerobic threshold, exercise levels below the anaerobic threshold are recommended for patients with cardiac diseases.

Aged↗
PubMed1995

A simple maneuver in follow-up digital subtraction angiography for multiple coronary-aorta bypass grafts.

A simple maneuver in intraarterial digital subtraction angiography (DSA) is proposed to improve the images of left internal thoracic artery bypass grafts (LITAGs). A contrast flush in the left subclavian artery, using a catheter that had been percutaneously introduced from the left brachial artery, was carried out in 14 patients with multiple coronary-aorta bypass grafts (CABGs) after aortic DSA. The side-hole portion of the catheter tip was positioned in the proximal left subclavian artery as the coiled portion remained in the aortic arch. Nonionic contrast medium (350 mg/ml of iodine) was injected with an automatic injector in a volume of 6-8 ml and at a flow rate of 3-4 ml/sec. Left subclavian arterial flush DSA delineated the LITAGs excellently in 11, well in 3, and fairly or poorly in none of the 14 cases. There were no complications in any of these cases. A supplemental contrast flush of the left subclavian artery with a pigtail catheter following aortic DSA improves the diagnosis of multiple CABG patency.

Aged↗
PubMed1995

T1 measurements with clinical MR units.

To improve accuracy and feasibility of the proton spin-lattice relaxation time (T1) measurements in routine Magnetic Resonance Imaging (MRI), a phantom with polyvinyl alcohol gels and gadrinium diethylene triamine pentaacetic acid solutions was imaged with 1.5T clinical MR units and T1s were calculated by fitting several models to the observed signal intensities. When an inversion-recovery sequence was applied, we were able to measure T1 with a high degree of precision by taking into account the imperfection of the inversion pulse. With a Turbo-fast low angle shot sequence, we were able to obtain T1 in a short time, but low signal-to-noise ratio limited the precision. Signal intensity with SE sequence was susceptible to variation with the effective flip angle of 90 degrees RF pulse and not suited for T1 measurement.

Image Processing, Computer-Assisted↗
PubMed1995

Monitoring accumulative fatigue of finger by autoregressive modeling of physiological tremor.

In this study, block data structured autoregressive (AR) method is used to evaluate fatigue, based on physiological tremor during and after loading a weight mass on the index finger. The temporal changes in the prediction coefficients and the reflection coefficients are determined. AR spectral estimation with the ninth-order is obtained and presented in graphical form. The results indicate that the first prediction coefficient a1 can be used to characterize the state of fatigue of finger muscle and the other prediction coefficients do not show any tendency for the finger load. The coefficient a1 can be applied to monitor the accumulative fatigue induced by the weight loading for a duration of time.

Adult↗
PubMed1995

Physiological tremor under pseudo-fraction gravity.

The effect of pseudo-fraction gravity on physiological tremor of the human finger (finger tremor) has been examined experimentally by immersing an index finger into water at different immersion levels. The pseudo-fraction gravity, gamma G, was established by water buoyancy at immersion level omega, G being gravitation acceleration and gamma between zero and unit. The nature of variations of finger tremor under the influence of gamma G is estimated based on FFT spectral analysis. It is illustrated that with a decrease in gamma, or equivalently an increase in omega, two dominant peaks remaining approximately constant in frequencies around 10Hz and 20Hz are found, while peak amplitude is decreased rapidly for higher peak and slowly for lower one. Theoretically the effect of pseudo-fraction gravity is analyzed in terms of a specific model for finger tremor. The experimental results presented in this paper are predicted rather well by two resonant modes which occurred in our model system. It is possible to conclude that the model, which is characterized by a pair of antagonistic muscles and two reflex pathways, provides an adequate quantitative description of finger tremor.

Adult↗
PubMed1995

Effects of weight load on physiological tremor: the AR representation.

The propriety of the autoregressive (AR) method as a means of processing the signals of physiological tremor of human finger (finger tremor) was investigated. Application of the Akaike's criterion demonstrated that the 15-th order AR model was required to describe the recordings of finger tremor. According to Burg's algorithm, both AR spectrum and AR parameters were estimated to study the effects of various weight loads on finger tremor. It was found that, (1) the amplitude of AR spectrum was apparently enhanced by adding the load; (2) the first prediction coefficient (a1) and the first reflection coefficient (rho 1) significantly declined by increasing the weight loads. The results were compared with the calculations from FFT (Fast Fourier Transform) and autocorrelation function. Simple physical interpretation of the AR parameters (i.e. a1 and rho 1) was discussed in relation with system's resonant modes.

Algorithms↗
PubMed1995

Metabolism of sertindole: identification of the metabolites in the rat and dog, and species comparison of liver microsomal metabolism.

1. The main exretion pathways of a novel antipsychotic drug, sertindole, in the rat and dog are faecal excretion via intestinal secretion and biliary excretion respectively. 2. Similar liver microsomal metabolic patterns were observed in the rat, monkey, and man, and Lu 30-131 (5-hydroxy-serindole) and Lu 30-148 (4-hydroxy-serindole) were the major metabolites, and Lu 25-073 (nor-sertindole) and Lu 28-092 (dehydro-sertindole) were minor ones. In the dog, however, Lu 31-096 (3'-fluoro-4'-hydroxy-sertindole) and Lu 30-148 (4-hydroxy-sertindole) were the major metabolites, and Lu 25-073 (nor-sertindole), Lu 28-092 (dehydro-sertindole), and Lu 30-131 (5-hydroxy-sertindole) were minor ones. These findings suggest that the metabolism of sertindole in man resembles those in the rat and monkey and is different from that in the dog. 3. Rat in vitro and in vivo liver metabolites, dog liver microsomal metabolites, and dog biliary metabolites were isolated and identified by liquid chromatography/mass spectrometry and/or 1H-nmr. 4. Two metabolites, Lu 31-096 (3'-fluoro-4'-hydroxy-sertindole) and Lu 31-154 (3'-fluoro-4'-hydroxy-dehydro-sertindole), were formed via the 'NIH shift' mechanism. 5. Sertindole is metabolized by hydroxylation at the 4- and 5-positions on the imidazolidinone ring, N-dealkylation, and an NIH shift at the fluorophenyl group. Further metabolism (dehydration, oxidation, hydroxylation, glucuronidation and sulphation) was also observed. 6. In the rat, oxidation at the imidazolidinone ring and N-dealkylation are the main metabolic reactions. On the other hand, in the dog, the NIH shift at the fluorophenyl group, followed by conjugation is the main metabolic pathway.

Animals↗
PubMed1995

[Immunohistochemical study on temporal bone of autopsy cases with Mycobacterium leprae infection].

Three temporal bones were obtained en bloc from autopsy cases with lepromatous leprosy from the middle cranial fossa side after removing the brain. After fixation with 10% formalin followed by sufficient decalcification, the specimens were embedded in paraffin en bloc and cut serially to stain every 10th section with hematoxylin and eosin (H&E) for anatomical orientation. An immunohistochemical study with anti-neurofilament, anti-MBP (myelin basic protein), anti-BCG (Bacillus Calmette-Gue'rin) and anti-PGL (Mycobacterium leprae-specific antiphenolic glycolipid-I) antibodies were performed to vestibular, cochlear and facial nerves, respectively, on the basis of anatomical orientation of the adjacent H&E sections. In one of three cases, positive staining by anti-PGL antibodies was recognized only in the facial nerve both in its internal auditory meatal and tympanic portions. However, even in this case, no neural damage was observed either by anti-neurofilament nor anti-MBP stainings. This finding supports the possibility of central neural infection by Mycobacterium leprae.

Aged↗
PubMed1995

[Treatment of advanced renal cell carcinoma with a combination of interferon alpha and gamma].

A total of 29 patients with advanced renal cell carcinoma entered a pilot study of combination therapy with interferon alpha (IFN-alpha) and interferon gamma (IFN-gamma). IFN-alpha (HLBI: 3 x 10(6) IU, BALL 1:5 x 10(6) IU, IFN-alpha-2a: 9 x 10(6) IU or IFN-alpha-2b: 6 x 10(6) IU) was given intramuscularly every day and IFN-gamma (IFN-gamma-1a: 3 x 10(6) JRU) was given intravenously by drip infusion 3 times a week (every 2-3 days). The treatment was continued for 3 months as the induction therapy, and then the tumor response was evaluated. Of the 22 evaluable patients, 4 achieved a partial response (PR), 10 showed no change (NC), and in 8 the disease had progressed (PD) during the therapy. Thus, the overall response rate was 18.2% [95% confidence interval (CI) 2.1-34.3%]. A favorable response tended to be obtained in patients with good performance status or small pulmonary metastases, or in those who had no prior therapy with IFN-alpha, who received this treatment immediately subsequent to radical nephrectomy, or who received IFN-gamma as much as possible according to this regimen. Toxicity was evaluated in 28 patients: fever, general fatigue, anorexia, leukocytopenia and impaired liver function were frequently noted, and 3 patients were withdrawn from the study because of such adverse effects. In patients who had a PR or NC, the same dosage of IFN-alpha was continued to be given intramuscularly 2-3 times a week (every 2-4 days) as the maintenance therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Metastatic adrenocortical carcinoma treated by repeated resection: a case report of long-term survival over 18 years.

A case of recurrent and metastatic nonfunctioning adrenocortical carcinoma in a 40-year-old woman is reported. The patient received 4 laparotomies and 1 thoracotomy for recurrent and metastatic disease after removal of the primary adrenal tumor. She has been alive for over 18 years following multiple surgery for diseases after the first adrenalectomy. In selected patients with recurrence and/or metastasis, repeated surgical resection offers the possibility of a cure or extended palliation.

Adrenal Cortex Neoplasms↗
PubMed1995

Enhanced mitogen-induced proliferation of rat splenocytes by low-dose whole-body X-irradiation.

To elucidate the stimulative effect on the immune system, we studied the effect of acute low-dose whole-body X-irradiation on the mitogen-induced proliferative responses of rat splenocytes and thymocytes. Concanavalin A (Con A)-induced mitogen response of rat splenocytes 4 hours after 5 cGy irradiation was significantly higher (by 80%, p < 0.02) than that in sham-irradiated controls; whereas that of rat thymocytes did not show change after irradiation of 1-10 cGy. In the rats X-irradiated with doses greater than 25 cGy, Con A-induced mitogen responses of splenocytes and thymocytes were reduced. In a way similar to the Con A-induced mitogen response of splenocytes, the mitogen response of splenocytes induced by phytohemagglutinin (PHA) or lipopolysaccharide (LPS) was significantly increased by X-irradiation with 5 cGy (by 50%, p < 0.02). The enhancement of mitogen response of splenocytes was observed within a few hours after irradiation, being a temporary effect. After 5 cGy irradiation the level of leukotriene B4 (LTB4) in the supernatant fraction of the splenocyte suspension showed a significant increase (by 40%, p < 0.05).

Animals↗
PubMed1995

[Diagnosis of Churg-Strauss syndorme with trans-bronchial lung biopsy].

A 69-year-old woman was hospitalized several times because of asthma attacks. Laboratory data revealed an increase in eosinophils and elevation of serum IgE. Both chest radiographs and computed tomography showed fine nodular shadows in both lung fields. Tissue samples obtained by trans-bronchial lung biopsy (TBLB) revealed extra-vascular granuloma. The patient complained of numbness of the extremities and neuron conduction velocity was low. Based on these findings, Churg-Strauss syndrome was diagnosed. Prednisolone improved the patient's symptoms. Patients with this syndrome reportedly respond well if it is diagnosed and treated with corticosteroids early. Chest roentgenography reveals various abnormal shadows in patients with this syndrome. For early diagnosis, TBLB is helpful and comparatively safe. This case was unusual because extra-vascular granuloma was found by TBLB.

Aged↗