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Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 73 records · Page 4Linked to original sources
PubMed2001

Validity and reliability of single-item questions about physical activity.

The Japan Collaborative Cohort Study for Evaluation of Cancer Risk Sponsored by Monbusho (JACC Study) included in its self-administered questionnaires some single-item questions concerning physical activity. We examined the validity of the questions among 1,730 Japanese adults and the reliability of the questions among 1,075 Japanese adults. The validity of the sports and physical exercise questions was estimated by comparing the self-administered questionnaire responses with the time spent on the activity and the energy expenditure index for the previous 12-month period, elicited by the interviewing method used in the Japan Lifestyle Monitoring Study with a minor modification. The Spearman's rank correlation coefficients ranged from 0.43 to 0.60, showing moderate correlations. On the other hand, test-retest reliability was estimated by comparing the responses from two separate surveys conducted roughly one year apart. Weighted kappa coefficients of sports and physical exercise questions, classified according to sex and age, ranged from 0.39 to 0.56, showing moderate reliability; and those of a question about walking ranged from 0.25 to 0.39, showing fair reliability. We suggest that measuring physical activity level with these single-item questions may be appropriate for establishing baseline data that reflects long-term physical activity in a large-scale cohort study targeting lifestyle-related diseases.

Adult↗
PubMed2001

The predictive value of p53, Ki-67 and angiogenetic factors in primary hypopharyngeal carcinoma.

To evaluate the predictive role of the oncogene p53, the proliferating marker Ki-67, angiogenic factors platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/dThdPase) and vascular endothelial growth factor (VEGF) in primary hypopharyngeal carcinoma, we immunohistochemically studied a series of 84 primary hypopharyngeal carcinoma patients who were treated at the Department of Otolaryngology of Kurume University Hospital between 1990 and 1997. The correlation of each score according to the intensity and percentage of the labeled cells with the TNM stage, histological grade, metastasis and survival status was analyzed. The positive rate of p53 was 52.4%. The percentages of Ki-67 labeled cells in patients with or without metastasis showed a significant difference (p = 0.011). VEGF also showed a significant difference between the live and death groups (p < 0.05) and also among the differentiation group (p < 0.05). A statistically significant correlation was also seen between the score of Ki-67 and VEGF (r = 0.438, p < 0.001) or the score of Ki-67 and PD-ECGF (r = 0.259, p < 0.001), respectively. In conclusion, the present study suggests that a correlation exists between proliferating and angiogenesis, and VEGF and Ki-67 are thus considered to be possible prognostic discriminators in hypopharyngeal carcinoma.

Adult↗
PubMed2001

The biochemical analysis of neurotransmitters in central neurocytomas.

Central neurocytomas are rare benign intraventricular tumours composed of small round synaptophysin-positive cells, suggesting a neuronal origin of these tumour cells. Although past electron microscopic studies demonstrated synaptic vesicles in the synapse of central neurocytomas, the kinds of neurotransmitters in central neurocytomas have never been identified. In this study we analyzed neurotransmitters in an attempt to clarify the tumorigenesis of central neurocytomas. We studied frozen central neurocytoma specimens from four patients. The tissue levels of glutamate and GABA (gamma-aminobutyric acid) in the tumours were determined by gas chromatography-mass spectrometry (GC-MS) using a selected ion monitoring method. The tissue levels of acetylcholine, choline, catecholamines and metabolites of catecholamines in the tumours were measured by high-performance liquid chromatography combined with electrochemical detection. Choline was found in extremely high concentration in all central neurocytomas when compared with levels in controls. In one central neurocytoma, GABA was found in extremely high concentration compared with controls. In all central neurocytomas, glutamate was found in lower or identical concentrations compared with controls. In all central neurocytomas and controls, dopamine and catecholamine concentrations were extremely low. These results indicated that the histogenesis of central neurocytomas begins with the subependymal stem cells, which have the potential to differentiate into cholinergic or GABA neurons.

Adult↗
PubMed2001

[Model of biological equivalent dose distribution modified by volume effect in radiotherapy].

This paper demonstrates that a biologically equivalent dose distribution including volume effect can be generated. Since the time-dose-fractionation (TDF) concept is convenient for comparing various radiation treatment schedules, TDF distribution maps are made on the basis of the physical dose distribution. On the other hand, the dose volume histogram is useful to evaluate volume effect, but is not necessarily an easy approach owing to the absence of spatial linkage. If distribution maps also representing the volume effect could actually be made, it would become easier to simultaneously predict both tumor control probability and the normal tissue complication rate. Because such tools should be very useful for planning radiotherapy, we proposed an experimental volume effect model. In this, one pixel is affected by all its surrounding pixels and the effect depends on the distance between pixels, volume, and the irradiated dose of another pixel. When the model was adapted to the conventional power law model, we could acquire a new equation with mathematical analysis. This permitted us to calculate the volume effect on each voxel within the treatment volume. Using a personal computer and treatment planning system, we calculated the "TDF-volume" distribution and drew maps based on this equation and the TDF values of each voxel for radiotherapy of a pelvic tumor.

Humans↗
PubMed2001

The characteristics of screened patients with abdominal aortic aneurysm.

BACKGROUND: Screening for abdominal aortic aneurysm (AAA) has not yet been established in Japan. We therefore report the characteristics of a screened population and discuss the implications of screening using ultrasound in Japan. METHODS: The subjects in our screening group were composed of 4428 participants who were 60 years of age or older. Aneurysm was detected in 16 cases, 15 males and 1 female, the detection rate being 0.4% in total and 0.9% in the males. We compare the characteristics of screened patients (n = 16) with non-screened patients operated on for abdominal aortic aneurysm (n = 166). RESULTS: There were no significant differences in the mean age or in the female ratio between the screened and non-screened groups (71 vs 70 y/o, 6% vs 13%, respectively). Solitary iliac aneurysms were significantly (p < 0.05) more frequent in the screened than in the non-screened group (19% vs 3%). The size of aneurysm in the screened group was significantly (p < 0.05) smaller compared with the non-screened group. Sixty-three per cent of the screened group and only 8% of the non-screened group had an aneurysm less than 40 mm in size. Aneurysm was palpable in only 31% of those of the screened group. There were no significant differences between the groups in the frequency of arteriosclerotic risk factors such as hypertension, ischaemic heart disease, diabetes mellitus, peripheral vascular disease and smoking habits. Surgical treatment was selected in 7 out of 16 screened patients. The remaining 9 patients with small-sized abdominal aortic aneurysms have been carefully followed up. CONCLUSIONS: Screening for abdominal aortic aneurysm using ultrasound is advisable especially for male participants and for the detection of iliac aneurysms. This screening procedure is useful for early detection because the screened aneurysm is generally small-sized and impalpable.

Aged↗
PubMed2001

[Spontaneous dissection of the anterior cerebral artery presenting subarachnoid hemorrhage and cerebral infarction: a case report].

A case is reported of anterior cerebral artery dissecting aneurysm presenting with subarachnoid hemorrhage and cerebral infarction. A 50-year-old man presented with sudden onset of weakness of the left lower limb was admitted to our hospital. CT scan on admission showed a subarachnoid hemorrhage in the interhemispheric fissure and CT on the 6th day demonstrated a cerebral infarction on the right medial frontal lobe. A carotid angiogram 12 hours after the onset showed no aneurysmal lesion, but, the angiogram repeated 11 days after the onset revealed an aneurysmal dilatation with distal narrowing at the right A2-A3 segment. To prevent rebleeding, we performed a wrapping procedure through the interhemispheric route on the 18th day after onset. The postoperative course was uneventful. We reviewed 27 previously reported cases with symptomatic dissecting aneurysm confined to the anterior cerebral artery.

Aortic Dissection↗
PubMed2001

[A surgical treatment for ischemic heart disease associated with systemic lupus erythematodes: report of a case].

We reported a case of coronary artery bypass grafting (CABG) associated with systemic lupus erythematodes (SLE). A 45-year-old male who had been treated for SLE with prednisolone for 9 years was transferred to our department for a surgical treatment due to ischemic heart disease (IHD). We successfully performed CABG resolving various perioperative complications. The intensive care is indispensable in the case of IHD with SLE.

Anti-Inflammatory Agents↗
PubMed2001

Cerebral arterial air embolism following CT-guided lung needle marking. Report of a case.

We report a case of survival following a temporary cerebral air embolism, which occurred immediately after CT guided lung needle marking. A 24-year-old man was referred to our hospital for resection of a pulmonary nodule. To localize the tumor, lung needle marking under CT guidance was performed. Almost immediately, the patient experienced symptoms of cerebral arterial air embolism. The following day, the symptoms diminished, and a brain CT showed no abnormal lesions. A video-assisted thoracoscopic wedge resection was performed as scheduled, the patient's postoperative course was uneventful, and he was discharged in relatively good condition.

Adult↗
PubMed2001

[Successful treatment of a patient with low pressure syndrome associated with gait disturbance].

The authors report an unusual case of low intracranial pressure (ICP) syndrome that was successfully treated by the placement of an anti-siphon device (ASD). This 36-year-old male had suffered suprasellar germinoma with hydrocephalus and had had a V-P shunt following radiotherapy. Sixteen years later he developed gait disturbance and somnolence and MRI demonstrated a small lateral ventricle as well as a diffuse dural enhancement. A lumbar tap revealed a low ICP of 12 mmH2O. Because of this, an ASD was placed in the patient. Postoperatively, his symptoms of gait and consciousness disturbance improved. Typical clinical findings of low ICP syndrome such as headache were not observed in this case. To our knowledge, no symptom of gait disturbance with low ICP has been reported previously. We present an interesting case of low ICP syndrome with gait disturbance and discuss the mechanism of the symptoms. Symptoms of this patient were due at first to brain ischemia. After convulsion and consciousness disturbance due to low intracranial pressure, the symptoms increased in strength until gait disturbance occurred. The possibility is suggested that gait disturbance in this patient was due both to brain ischemia and low intracranial pressure.

Adult↗
PubMed2001

[Relationship between skipping breakfast and cardiovascular disease risk factors in the national nutrition survey data].

PURPOSE: To investigate the relationship between skipping breakfast and cardiovascular disease risk factors such as blood pressure, serum lipids, smoking, and lock of exercise. MATERIALS AND METHODS: Data from the National Nutrition survey conducted by the Ministry of Health and Welfare, from 1995 through 1997 were employed for the analysis. Data were used only if subjects were between 20 and 59 years old and had participated in the nutrition survey, and values for height and weight, blood pressure, serum lipids, blood sugar, number of steps per day, and smoking, drinking, and exercise habits were available. The number of subjects with data available for all of the above was 11,778 (4,438 men and 7,340 women). Analyses were performed separately by sex. The relationship between skipping breakfast and continuous variables such as nutrient intake ratio (nutrient intake divided by recommended dietary allowances), body mass index, blood pressure, serum lipids, blood sugar, and the number of steps per day was examined controlling for age using analysis of covariance (ANCOVA). The relationship between skipping breakfast and categorical variables such as smoking, drinking, and exercise habits was assessed controlling for age using Cochran-Mantel-Haenszel statistics. RESULTS: The younger the generation, the higher the rate of skipping breakfast. The rate of skipping breakfast in men was twice as high as in women. The breakfast skippers tended to intake less energy and calcium, both in men and women, that non-skippers. Female skippers tended to intake less iron and vitamin D. The number of steps per day was smaller in breakfast skippers than that in non-skippers both in men and women. Male skippers tended to have higher blood pressure than non-skippers, and female skippers tended to have a higher serum total cholesterol level than non-skippers. The breakfast skippers tended to smoke more than non-skippers, both in men and women, and female skippers tended to drink more alcohol and take less exercise. CONCLUSIONS: Skipping breakfast is related to cardiovascular risk factors such as lack of exercise, smoking, high blood pressure, and high serum total cholesterol.

Adult↗
PubMed2001

[Pulmonary embolism following lung resection: a case report and review of the Japanese literature].

A 73-year-old male was admitted to our hospital with an abnormal shadow on a chest X-ray film. Chest CT demonstrated that a tumor shadow measuring 23 x 22 mm in size with pleural retraction was located in the right lower lobe. Transbronchial lung biopsy yielded a diagnosis of primary pulmonary adenocarcinoma. We performed a right lower lobectomy with mediastinal lymph node dissection. The patient suddenly complained of a syncope attack, tachycardia, hypotension, and hypoxemia 2 days after surgery. A perfusion lung scintigram with Tc-99 m macroaggregated albumin demonstrated localized defects at both the left lower lobe and a part of the left upper lobe. Thrombolytic and anticoagulation therapy with urokinase and heparin were immediately started. A postoperative lung scintigram 14 days after the onset of pulmonary thromboembolism showed normal filling of the left lung. The patient was discharged on the 37th postoperative day, and he has been followed up with anticoagulation therapy.

Acute Disease↗
PubMed2000

Activated cAMP-response element-binding protein regulates neuronal expression of presenilin-1.

Upon binding to the cAMP-response element of a gene's promoter, the transcription factor known as cAMP-response element-binding protein (CREB) facilitates transcription of many different neuronal genes including those involved with synaptic function. Based on our previous reports of gene structure (GenBank accession number AF029701 ), we now demonstrate that activated CREB binds to the proximal promoter of the human presenilin-1 (PS-1) gene to activate PS-1 transcription in rat and in human neuronal cells. Specific stimulation of the N-methyl-d-aspartate subtype of neuronal glutamate receptors activates CREB and results in increased PS-1 expression. Similarly, treatment with brain-derived neurotrophic factor activates CREB and increases PS-1 expression in a dose-dependent fashion. By using adenovirus vectors expressing dominant negative forms of CREB, we were able to show that induction of PS-1 expression requires the activation of CREB. Conversely, constitutive expression of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) results in activation of CREB and increased PS-1 expression that can be blocked by the addition of selective MEK inhibitors. Our findings suggest a hypothesis where stimulation of N-methyl-d-aspartate receptors signals CREB activation to enhance PS-1 gene product expression that contributes to normal neuronal functions.

Adenoviridae↗
PubMed2000

Three types of putative presympathetic neurons in the rostral ventrolateral medulla studied with rat brainstem-spinal cord preparation.

To study the electrophysiological properties of presympathetic neurons in the rostral ventrolateral medulla (RVLM), intracellular recordings were performed by the whole-cell patch-clamp technique. We utilized the neonatal rat brainstem-spinal cord preparation, in which the sympathetic neuronal network is thought to be preserved, unlike in slice preparation. In response to stimulation in the ipsilateral Th2 spinal segment including intermediolateral cell column (IML), 33 of 151 non-respiratory RVLM neurons showed antidromic action potentials with a constant latency of 45 ms, and can be considered as presympathetic neurons. We classified and characterized the RVLM presympathetic neurons into three types: 'regularly firing neurons (n=7)', which showed ramp depolarization and frequent action potentials (4.2+/-0.9 spikes/s) with rare excitatory postsynaptic potentials (EPSPs); 'irregularly firing neurons (n=21)', which exhibited many EPSPs that modulated the firing rate; and 'silent-type neurons (n=5)', which discharged action potentials only during current-induced depolarization. Lucifer-Yellow staining showed that the irregularly firing neurons were significantly larger and had more dendrites than the regularly firing neurons. All regularly firing neurons retained their discharges during low-Ca2+ -high-Mg2+ superfusion that blocks synaptic input, whereas the discharges in 11 of 16 irregularly firing neurons were abolished, suggesting that the regularly firing neurons discharged independently of synaptic input. Seven of 31 RVLM neurons were hyperpolarized by stimulation of vagal afferent nerves. In summary, three types of RVLM presympathetic neurons were characterized by the patch-clamp technique in the brainstem-spinal cord preparation, in which the connection was preserved from vagal afferent to the Th2 spinal segment through the RVLM. Since antidromic action potentials were demonstrated by stimulation in the Th2 spinal segment in 33 neurons of all three types, all types of RVLM neurons constitute a part of the sympathetic neuronal network.

Action Potentials↗
PubMed2000

Distinct methylation patterns of two APC gene promoters in normal and cancerous gastric epithelia.

The adenomatous polyposis coli (APC) tumor suppressor gene is mutationally inactivated in both familial and sporadic forms of colorectal cancers. In addition, hypermethylation of CpG islands in the upstream portion of APC, a potential alternative mechanism of tumor suppressor gene inactivation, has been described in colorectal cancer. Because a subset of both gastric and colorectal cancers display the CpG island methylator phenotype, we hypothesized that epigenetic inactivation of APC was likely to occur in at least some gastric cancers. APC exhibits two forms of transcripts from exons 1A and 1B in the stomach. Therefore, we investigated CpG island methylation in the sequences upstream of exons 1A and 1B, i.e., promoters 1A and 1B, respectively. We evaluated DNAs from 10 gastric cancer cell lines, 40 primary gastric cancers, and 40 matching non-cancerous gastric mucosae. Methylated alleles of promoter 1A were present in 10 (100%) of 10 gastric cancer cell lines, 33 (82.5%) of 40 primary gastric cancers, and 39 (97.5%) of 40 noncancerous gastric mucosae. In contrast, promoter 1B was unmethylated in all of these same samples. APC transcripts from exon 1A were not expressed in nine of the 10 methylated gastric cancer cell lines, whereas APC transcripts were expressed from exon 1B. Thus, expression from a given promoter correlated well with its methylation status. We conclude that in contrast to the colon, methylation of promoter 1A is a normal event in the stomach; moreover, promoter 1B is protected from methylation in the stomach and thus probably does not participate in this form of epigenetic APC inactivation.

Adolescent↗
PubMed2000

Identification of catalytic nucleophile of Escherichia coli gamma-glutamyltranspeptidase by gamma-monofluorophosphono derivative of glutamic acid: N-terminal thr-391 in small subunit is the nucleophile.

gamma-Glutamyltranspeptidase (EC 2.3.2.2) is the enzyme involved in glutathione metabolism and catalyzes the hydrolysis and transpeptidation of gamma-glutamyl compounds such as glutathione and its derivatives. The reaction is thought to proceed via a gamma-glutamyl-enzyme intermediate where a hitherto unknown catalytic nucleophile is gamma-glutamylated. Neither affinity labeling nor site-directed mutagenesis of conserved amino acids has succeeded so far in identifying the catalytic nucleophile. We describe here the identification of the catalytic nucleophile of Escherichia coli gamma-glutamyltranspeptidase by a novel mechanism-based affinity labeling agent, 2-amino-4-(fluorophosphono)butanoic acid (1), a gamma-phosphonic acid monofluoride derivative of glutamic acid. Compound 1 rapidly inactivated the enzyme in a time-dependent manner (k(on) = 4.83 x 10(4) M(-1) s(-1)). The inactivation rate was decreased by increasing the concentration of the substrate. The inactivated enzyme did not regain its activity after prolonged dialysis, suggesting that 1 served as an active-site-directed affinity label by phosphonylating the putative catalytic nucleophile. Ion-spray mass spectrometric analyses revealed that one molecule of 1 phosphonylated one molecule of the small subunit. LC/MS experiments of the proteolytic digests of the phosphonylated small subunit identified the N-terminal peptide Thr391-Lys399 as the phosphonylation site. Subsequent MS/MS experiments of this peptide revealed that the phosphonylated residue was Thr-391, the N-terminal residue of the small subunit. We conclude that the N-terminal Thr-391 is the catalytic nucleophile of E. coli gamma-glutamyltranspeptidase. This result strongly suggests that gamma-glutamyltranspeptidase is a new member of the N-terminal nucleophile hydrolase family.

Aminobutyrates↗
PubMed2000

Prognostic significance of persistent right ventricular dysfunction as assessed by radionuclide angiocardiography in patients with inferior wall acute myocardial infarction.

We evaluated cardiac hemodynamics and long-term prognosis in patients with right ventricular (RV) acute myocardial infarction (AMI) using Fourier phase and amplitude analysis of radionuclide angiocardiographic scanning. In 143 patients with RV AMI, delayed phase and low amplitude in radionuclide RV images persisted in 54 patients (persistent RV dysfunction group) 3 months after AMI, but disappeared in the remaining 89 patients (improved RV function group). No significant differences were present in RV dimensions, left ventricular (LV) wall motion, LV ejection fraction, or RV ejection fraction between these groups during the acute phase. At 3 months, RV dimension and LV and RV wall motion indexes were significantly higher (p = 0.0292, p = 0.0124, p<0.0001, respectively), and LV and RV ejection fractions were lower (p = 0. 0174 and p = 0.0008, respectively) in the persistent RV dysfunction group. Percutaneous transluminal coronary angioplasty in the acute phase was performed in a smaller group of patients (15% vs. 34%, p = 0.0223), and the degree of residual stenosis in the proximal right coronary artery was significantly greater in the persistent RV dysfunction group than in the improved RV function group (82+/-22% vs. 53+/-30%, p<0.0001). The 8-year survival rate was significantly lower in the persistent RV dysfunction group (p<0.0001). Persistent abnormality of phase and amplitude in radionuclide RV images was a significant independent predictor of long-term survival (odds ratio 10.42; 95% confidence interval 3.65 to 29.71; p<0.0001). Radionuclide angiocardiographic Fourier phase and amplitude scanning can detect persistent RV dysfunction in patients with RV AMI and can predict patient outcome.

Aged↗
PubMed2000

Accelerated radiotherapy for T1, 2 glottic carcinoma: analysis of results with KI-67 index.

PURPOSE: Hyperfractionated and accelerated radiotherapy without a split was performed to improve the local control probability of early glottic carcinomas. We analyzed the results of this regimen by using the Ki-67 index. METHODS AND MATERIALS: Over a 12-year period, 85 T1N0M0 glottic cancers and 50 T2N0M0 glottic cancers were treated with conventional fractionation (CF) from 1984 to 1989 and with accelerated fractionation (AF) since 1990. The CF program consisted of five daily fractions of 2 Gy per week, for a total of 64 Gy. The AF program consisted of 1.72 Gy per fraction, two fractions per day, 5 days a week, for a total of 55 or 58 Gy. The specimens, taken before radiotherapy, were immunohistochemically stained with anti-Ki-67 antibody. RESULTS: The 5-year local control probability for T1 tumors was 79.6 +/- 6.9% with CF treatment, whereas with AF it was 86.9 +/- 5.6%. For T2 tumors it was 62.7 +/- 12.2% with CF, whereas it was 74.7 +/- 7.8% with AF. The difference between CF and AF did not reach the point of statistical significance. However, when T1 tumors had a Ki-67 index lower than 50%, the local control rate achieved with AF was significantly better than that with CF (p = 0.018). When the tumors had a Ki-67 index that was 50% or more, there was no difference in the local control rate between CF and AF, whether they were T1 or T2. The peak mucosal reactions at the larynx and/or hypopharynx were much more severe and appeared at smaller doses and earlier in AF than in CF. The patients with AF showed no severe late complications. CONCLUSIONS: AF could not obtain statistically significant improvement in local control probability of T1 or T2 glottic carcinomas.

Adult↗