Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 127 records · Page 7Linked to original sources

PubMed1999

Abdominal Aortic Dilatation in Japanese Residents.

The correlation between abdominal aortic dilatation and arteriosclerotic risk factors was studied in 2514 Japanese residents (947 men, 1567 women, mean age 70 years old). The aortic diameter was measured by ultrasound and an aortic dilatation was defined as above 30 mm in diameter, including abdominal aortic aneurysm (AAA). Forty-three (1.7%) patients with a dilated aorta and 2471 with a normal-sized aorta were compared. Abdominal aortic dilatation was significantly (p < 0.01) more frequent in men than in women (3% vs 0.7%). Obesity and hyperlipidemia were slightly (p < 0.1) more frequent in patients with a dilated aorta than in those with a normal-sized aorta. There were no significant differences between the two groups in mean age, frequency of smoking, diabetes mellitus, and coronary artery disease. In conclusion, male obesity and hyperlipidemia may be risk factors for aortic dilatation in Japan. Women may not be screened because of cost-effectiveness. The prevalence of aortic dilatation in Japan was lower than in European countries. However, screening for AAA using ultrasound would be advantageous when considering the grave prognoses of ruptured AAA.

Journal Article↗

PubMed1999

Biochemical markers of bone turnover and bone loss at the lumbar spine and femoral neck: the Taiji study.

The purpose of this study was to ascertain whether biochemical markers of bone turnover predict bone loss. The survey was carried out in Taiji, Wakayama Prefecture, Japan. From a list of inhabitants aged 40-79 years, 400 participants (50 men and 50 women in each of four age groups) were selected randomly. Bone mineral density (BMD) was measured, and blood and urine samples of all participants were examined to obtain values for eight biochemical markers: alkaline phosphatase (ALP), bone Gla protein (BGP), type I procollagen (carboxyterminal peptide of type I procollagen; PICP), cross-linked carboxyterminal telopeptide region of type I collagen (ICTP), and urinary excretion of calcium (Ca), phosphate (P), pyridinoline (Pyr), and deoxypyridinoline (D-Pyr). Each marker was evaluated as a predictor of the rate of bone change in lumbar spine and femoral neck BMD over a 3-year period. The value of Pyr was significantly related to the change of lumbar spine BMD in men (P = 0.009), and that of BGP was found to be significant in women (P = 0.045). By contrast, none of the bone markers significantly correlated with bone loss at the femoral neck. The coefficient of determination at the lumbar spine was 5% and 7% at the femoral neck only. We conclude that biochemical markers of bone turnover cannot predict bone loss rates in middle-aged or elderly Japanese men and women over a 3-year period with sufficient accuracy for use in clinical decision making.

Adult↗

PubMed1999

QT dispersion in patients with Duchenne-type progressive muscular dystrophy.

BACKGROUND: A high degree of QT dispersion is a risk factor for arrhythmic sudden death in patients with myocardial infarction and cardiomyopathy. Duchenne-type progressive muscular dystrophy (DMD) is also associated with the development of ventricular arrhythmias. The purpose of this study was to determine the relationship between QT interval dispersion and ventricular arrhythmias in patients with DMD. METHODS: Sixty-seven patients with DMD were studied. Standard 12-lead electrocardiograms and 24-hour Holter electrocardiograms were recorded, and the QT interval was determined in every lead of the standard electrocardiogram to determine the QT dispersion. QT dispersion was compared with the frequency of ventricular arrhythmias and the severity of skeletal muscle damage on the basis of the Swinyard and Deaver 8-stage scale. RESULTS: QT dispersion in all 67 patients averaged 54 +/- 18 ms. The QT dispersion was 49 +/- 16 ms in stage 5 patients, 61 +/- 22 ms in stage 6 patients, 52 +/- 17 ms in stage 7 patients, and 56 +/- 17 ms in stage 8 patients. Ventricular arrhythmias of Lown grade III or higher were observed in 3 of 35 patients with QT dispersion <60 ms and in 14 of 32 patients with QT dispersion >/=60 ms. Logistic regression analysis demonstrated that QT dispersion is an independent risk factor for ventricular arrhythmias of grade III or higher in patients with DMD. CONCLUSIONS: The incidence of ventricular arrhythmias of Lown grade III or higher was greater in patients with QT dispersion >/=60 ms than in patients with QT dispersion >60 ms. QT dispersion therefore is a risk factor for serious ventricular arrhythmias in patients with DMD.

Adolescent↗

PubMed1999

Differential effects of enalapril and nitrendipine on the fibrinolytic system in essential hypertension.

BACKGROUND: Impaired fibrinolysis is associated with thromboembolic complications in hypertensive patients. It has been reported that cardiovascular morbidity and mortality rates are high even after lowering the elevated blood pressure with antihypertensive drugs. The aim of this study was to assess the effect of clinically used dosages of enalapril and nitrendipine on the fibrinolytic system. METHODS: Tissue plasminogen activator antigen (tPA) and tissue plasminogen activator inhibitor-1 (PAI-1) activity were measured in 20 normotensive male subjects and 46 male patients with mild essential hypertension divided into 2 groups (22 patients treated with 5 to 10 mg enalapril once a day and 24 treated with 5 to 10 mg nitrendipine once a day) before and 3 months after drug administration. Plasma renin activity and norepinephrine concentration were also measured. RESULTS: There were no significant differences in basal characteristics between the 2 hypertensive groups. In both hypertensive groups, blood pressure was significantly reduced to a similar level after drug treatment. In the 2 hypertensive groups, plasma renin activity significantly increased after drug treatment; however, there were no significant changes in norepinephrine concentration. Before drug treatment, the 2 hypertensive groups had significantly higher tPA and higher PAI-1 activity than the normotensive subjects. In the enalapril group, there was no significant change in tPA although PAI-1 activity significantly decreased after drug treatment. In the nitrendipine group, there was no significant change in tPA although PAI-1 activity significantly increased after drug treatment. CONCLUSION: Thus enalapril improved impaired fibrinolysis but nitrendipine further aggravated fibrinolysis in essential hypertension. Considering the effect of antihypertensive drugs on the fibrinolytic system, more effective and beneficial treatment of hypertensives, especially at a high risk for thrombus formation might be selected.

Administration, Oral↗

PubMed1999

Mutations in mitochondrial control region DNA in gastric tumours of Japanese patients.

The non-coding control region of mitochondrial DNA (mtDNA), containing the hypervariable regions HV1 and HV2 and the D-loop region, was screened for mutations in 45 gastric tumours (15 tumours each of adenoma, differentiated adenocarcinoma and undifferentiated carcinoma). We found mutations in two of the 45 tumours (4%); a 1 bp A deletion at nucleotide position 248 in a differentiated adenocarcinoma and a G to A transition at nucleotide position 16,129 in an adenoma. We also observed 10 polymorphisms, four of which were not previously recorded. Both mtDNA mutations were present in replication error negative (RER-) tumours. Short mono- or dinucleotide repeats in the control region, such as (C)7, (A)5 or (CA)5, were not altered regardless of nuclear genetic instability. In summary, mtDNA is mutated in a subset of benign and malignant gastric tumours, but, disruption of the mtDNA repair system appears not to be significantly involved in gastric tumours of Japanese patients.

DNA Repair↗

PubMed1999

Trends in blood pressure and urinary sodium and potassium excretion in Japan: reinvestigation in the 8th year after the Intersalt Study.

Using the identical protocol of an Intersalt Study previously conducted, we undertook a new study (Intersalt-2) 8 years later. We measured changes in various factors affecting blood pressure (BP) including urinary sodium and potassium excretion in three districts of Japan: Osaka, Tochigi, and Toyama. Also we evaluated the trends in the relationships of those factors to BP. The Intersalt Study revealed that the average sodium excretion of all three study centres was high (particularly in Toyama) while potassium excretion was relatively low. The sodium/potassium ratio was therefore relatively high. The body mass index (BMI) was favourable, but the prevalence of heavy alcohol drinkers was high. Comparing the first to the second study reveals a decrease in sodium excretion in Toyama, although that area still had the highest value of the three study centres. The average potassium excretion increased only in Osaka. Sodium/potassium ratio decreased in all centres. BMI and the prevalence of heavy drinkers among the subjects of both studies were nearly the same. The trend of the relationship of sodium to BP in Osaka changed from negative to positive. In Toyama, it changed from positive to negative. It is thought that this negative relationship might occur in conjunction with a reduction in salt consumption in a population. In conclusion this study reveals that average sodium consumption in Japan remains high while potassium consumption is still low. As a factor in the prevention of hypertension, further efforts to reduce salt consumption and increase potassium intake are still needed.

Adult↗

PubMed1999

Monocyte rescue of human T cells from apoptosis is CD40/CD154 dependent.

The induction of T-cell apoptosis is regulated in part by monocytes (CD14+ cells). Human peripheral blood monocytes inhibited the spontaneous cell death of activated T cells in vitro. The inhibition of T-cell apoptosis did not require autologous monocytes. Inhibition required direct contact with monocytes and was not due to a soluble factor. Furthermore, treatment of monocytes with actinomycin D, cycloheximide and paraformaldehyde abrogated the anti-apoptotic activity of these cells. Blocking antibody to CD40 and CD154 (CD40 ligand) decreased the ability of monocytes to aid in T-cell survival, whereas, blocking LFA-1/I-CAM-1, Fas ligand and the CD4/major histocompatibility complex class II interaction did not affect the influence of monocytes on T-cell survival. This shows that monocytes rescue of activated T cells from apoptosis is dependent upon CD40/CD154 interaction.

Antibodies, Blocking↗

PubMed1999

Different nuclear/cytoplasmic distributions of RET finger protein in different cell types.

The RET finger protein (RFP), which belongs to the B box zinc finger protein family, has a tripartite motif consisting of a Ring finger, a B box finger and a coiled-coil domain. The RET finger protein becomes oncogenic when its tripartite motif is fused with the tyrosine kinase domain of the RET protein. This study examined the RFP expression in normal and tumor tissues by immunohistochemistry. RFP was detected in the nuclei of various cells, including peripheral and central neurones, hepatocytes, adrenal chromaffin cells and male germ cells. Among them, RFP was expressed at high levels in male germ cells such as primary spermatocytes and round spermatids, and formed a perinuclear cap structure in primary spermatocytes. On the other hand, high levels of cytoplasmic expression of RFP were observed in some plasma cells as well as solitary plasmacytoma and multiple myeloma. These results suggested that different nuclear/cytoplasmic distributions of RFP might play a role in the regulation of growth or differentiation of different cell types.

Animals↗

PubMed1999

Effects of bilateral jugular vein ligation on local cerebral blood flow.

The authors examined the effect of bilateral jugular vein ligation (JVL) on local cerebral blood flow (CBF). Local CBF was measured in the neocortex of the frontal lobe over a 1-week period in 10 freely moving male rats. Measurements were taken with the hydrogen clearance method before and after the rat underwent either an operation of bilateral JVL or a sham operation. After the sham operation, blood flow values did not change significantly compared with preoperative values. Blood flow values decreased rapidly in rats with JVL. For 3 hours after surgery, JVL values were significantly lower (p <0.05) than preoperative values were, then gradually they recovered and reached preoperative values within 48 hours. Histopathologic study showed no remarkable parenchymal damages in the brain of rats with JVL. These results show that bilateral JVL produces a reversible decrease in the CBF and does not cause histopathologic brain damages.

Journal Article↗

PubMed1999

CAG repeat length in the androgen receptor gene of infertile Japanese males with oligozoospermia.

We analysed the CAG repeat length in exon 1 of the androgen receptor gene in 59 idiopathic Japanese infertile males with oligozoospermia; 36 fertile males were also analysed as controls. The number of CAG repeats in infertile males ranged from 14 to 32 (mean 21.2+/-4.2), whereas the number of CAG repeats in fertile males ranged from 16 to 31 (mean 21.4+/-3.5). Among infertile males, six possessed a short form of 14 CAG repeats and three possessed 15 CAG repeats. On the other hand, fertile males did not possess the short form of 14 or 15 CAG repeats. The incidence of infertile males with 14 and 15 CAG repeats was significantly higher (P<0.05) than that of fertile males. Although the sample size is small, the results suggest that the reduction of CAG repeats in exon 1 of the androgen receptor is closely related to impaired spermatogenesis in infertile Japanese males.

Adult↗

PubMed1999

Microsatellite instability and hMSH2 gene mutation in a triple cancer (colon cancer, endometrial cancer, ovarian cancer) patient in hereditary non-polyposis colorectal cancer (HNPCC) kindred.

A patient who had triple cancer (colon cancer, endometrial cancer, and ovarian cancer) in HNPCC kindred is reported. Her family history revealed the occurrence of colon cancer in her paternal aunt and in two cousins, fulfilling the minimum HNPCC criteria. Microsatellite instability analysis revealed replication error (RER)+ in all cancer lesions at 2 microsatellite loci (D1S191, BAT 40). SSCP analysis suggested germline mutation in exon 2 of the hMSH2 gene. This case showed the importance of complete family-history investigations to identify HNPCC patients. In the near future, definitive diagnosis of HNPCC will be possible on the basis of DNA studies.

Adenocarcinoma↗

PubMed1999

Effects of amlodipine and cilnidipine on cardiac sympathetic nervous system and neurohormonal status in essential hypertension.

N-Type calcium channel antagonists may suppress sympathetic activity. The purpose of this study was to assess the effects of amlodipine and cilnidipine on the cardiac sympathetic nervous system and the neurohormonal status of essential hypertension. 123I-metaiodobenzylguanidine (MIBG) cardiac imaging was performed and blood samples were taken to determine plasma renin activity and plasma norepinephrine concentration before and 3 months after drug administration in 47 patients with mild essential hypertension. Twenty-four of the patients were treated with 5 to 10 mg/d of amlodipine; the other 23 were treated with 10 to 20 mg/d of cilnidipine. For comparison, 12 normotensive subjects were also studied. No significant differences were found in the basal characteristics between the 2 hypertensive groups. In both hypertensive groups, both the systolic and diastolic blood pressures were significantly reduced to similar levels 3 months after drug treatment. Before the drug treatment, the 2 hypertensive groups had a significantly higher washout rate and lower heart-to-mediastinum (H/M) ratio compared with the normotensive subjects. The H/M ratio significantly increased (P<0.05) in combination with a decreased washout rate (P<0.02) after drug treatment in the cilnidipine group. In the amlodipine group, a significant decrease in washout rate (P<0. 04) was noted, without an increase in the H/M ratio. However, no significant changes were found in plasma renin activity and plasma norepinephrine concentration in either group. Thus, in patients with essential hypertension, cilnidipine suppressed cardiac sympathetic overactivity and amlodipine had a little suppressive effect. Cilnidipine may provide a new strategy for treatment of cardiovascular diseases with sympathetic overactivity.

Adult↗

PubMed1999

Pseudoxanthoma elasticum with dipyridamole-induced coronary artery spasm: a case report.

In patients with pseudoxanthoma elasticum, severe organic coronary artery stenosis often occurs without coronary risk factors. However, this report presents the case of a 49-year-old woman with pseudoxanthoma elasticum who had coronary artery spasm with an angiographically normal coronary artery. In addition, coronary artery spasm was provoked with dipyridamole thallium-201 cardiac imaging.

Coronary Angiography↗

PubMed1999

Synthesis and characterization of intermediate and transition-state analogue inhibitors of gamma-glutamyl peptide ligases.

The phosphonodifluoromethyl ketone and phosphonofluoridate derivatives of L-glutamic acid were synthesized and characterized as analogues of the gamma-glutamyl phosphate intermediate and the tetrahedral transition state, respectively, for the inhibition of gamma-glutamylcysteine synthetase and glutamine synthetase. The former served as a poor inhibitor of both enzymes, but the latter inhibited glutamine synthetase with a Ki of 59 microM and partially inactivated the enzyme in an NH3- and ATP-dependent manner.

Adenosine Triphosphate↗

PubMed1999

Suppression of D-galactosamine-induced rat liver injury by glycosidic flavonoids-rich fraction from green tea.

Tea constituents that had a preventive effect on D-galactosamine-induced liver injury in rats were partially purified by column chromatography from a n-butanol-soluble fraction of green tea. The fraction containing glycosidic flavonoids was found to suppress the D-galactosamine-induced increase of plasma alanine aminotransferase and aspartate aminotransferase activities. These results indicate that glycosidic flavonoids contribute, at least in part, to the liver injury-preventive effect of green tea.

Alanine Transaminase↗

PubMed1999

Effects of a phosphate buffered extracellular (Ep4) solution in preservation and reperfusion injury in the canine liver.

The Ep4 solution, a phosphate buffered extracellular-type solution, is effective in canine lung transplantation following a 96-hour hypothermic (4 degrees C) preservation. In this experiment, we used this solution for liver preservation followed by transplantation. We compared the Ep4 solution with the lactated Ringer's (LR) and the Collins' M (CM) solution (a phosphate buffered intracellular-type solution) in two studies, 1) 48-hour liver preservation, and 2) orthotopic liver transplantation after 5-hour preservation. In the preservation study, purine nucleoside phosphorylase (PNP) levels as a marker of endothelial damage, and alanine aminotransferase (ALT) levels were significantly lower in the livers immersed into the Ep4 solution than in those immersed into other solutions at 36 and 48 hours after preservation. Microscopically, the endothelial injury occurred 24 hours after preservation in the CM solution, and 36 hours after preservation in the LR and Ep4 solutions. In the transplantation study, serum PNP and ALT levels in the livers immersed in Ep4 solution showed a lower tendency compared with those in other solutions at the time of reperfusion, but the histological differences among three groups were not apparent. The present study suggests that the liver can be stored better for a longer time using Ep4 solution than using LR and CM solutions.

Alanine Transaminase↗

PubMed1999

A substitutional mutation in the DNA binding domain of the androgen receptor causes complete androgen insensitivity syndrome.

DNA analysis of the androgen receptor gene in a patient with complete androgen insensitivity syndrome identified a substitutional mutation (tyrosine converted to cysteine at position 571) in the DNA binding domain. In vitro transfection experiments with the patients' androgen receptor gene, indicated normal expression of the androgen receptor in transfected COS-7 cells compared to the wild type gene. There was also no evidence of impaired thermal stability of the 5 alpha-dihydrotestosterone-androgen receptor complex. However, the capacity of the androgen receptor to activate target gene transcription was found to be completely disrupted in a luciferase assay. These results confirmed that only one substitutional mutation in the DNA binding domain was related to the pathogenesis of the complete androgen insensitivity syndrome.

Adult↗

PubMed1999

[Acute empyema caused by Streptococcus milleri in early pregnancy].

A 40-year-old woman was admitted to our department complaining of left lateral chest pain and fever. She smoked 10 cigarettes per day. Chest radiographs revealed increased density in the upper left lung field and air-fluid level in the lower left lung field. A diagnosis of acute empyema was made, because pus was aspirated by thoracentesis. Streptococcus intermedius (Streptococcus milleri group) was isolated from samples of pleural effusion. The patient was successfully treated with a combination of antibiotics and surgical drainage. It became clear after discharge that she was in her 6th week of pregnancy. Laboratory findings showed decreased lymphocyte transformation in the PHA and Con-A tests. We reasoned, therefore, that smoking and decreased cellular immunity due to pregnancy might be causes of bacterial infections such as empyema.

Acute Disease↗