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Biomedical subjects

Y Tsuchiya

Publications and source records attributed to Y Tsuchiya.

At least 19 recordsLinked to original sources
PubMed2006

Correlations between bone mineral density and demographic, lifestyle, and biochemical variables in community-dwelling Japanese women 69 years of age and over.

INTRODUCTION: A few epidemiologic studies have comprehensively attempted to identify risk factors for low bone mineral density (BMD) in elderly Asian women. The purpose of this study was to identify demographic, lifestyle, and biochemical factors correlated with BMD in elderly Japanese women 69 years of age and over. METHODS: The study design was cross-sectional. The subjects were 583 ambulatory women aged 69 years and over, and their average age was 74.3 (SD 4.4) years. Predictor variables were age, reproductive history, anthropometric indices, grip strength, calcium intake, lifestyle information, and serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D (1,25(OH)(2)D), osteocalcin (OC), and undercarboxylated osteocalcin (ucOC) values. The outcome variable was forearm BMD measured with a DTX-200 osteometer. RESULTS: Simple linear regression analyses showed that BMD was significantly positively associated with body height, weight, body mass index, grip strength, serum albumin concentration, and "housework," and negatively associated with age, years since menopause, age at menarche, number of children, serum 1,25(OH)(2)D concentration, serum OC concentration, and ucOC concentration. The stepwise multiple regression analysis showed that weight (beta=0.00316, SE=0.00028, R(2)=0.180), age (beta=-0.00321, SE=0.00050, R(2)=0.108), log-transformed serum OC (beta=-0.0445, SE=0.0064, R(2)=0.053), log-transformed serum 1,25(OH)(2)D (beta=-0.0401, SE=0.0074, R(2)=0.050), "farmwork" (beta=0.00904, SE=0.00426, R(2)=0.005), and serum 25(OH)D concentration (beta=0.000281, SE=0.000120, R(2)=0.003) were significantly associated with BMD. CONCLUSION: It was concluded that body weight is a major predictor of forearm BMD among the factors measured in this study in independent Japanese women 69 years of age and over and that serum 1,25(OH)(2)D concentration may be associated with cortical BMD. Maintenance of body weight is very important for maintaining BMD in this population, unless a large weight aggravates obesity-related diseases. A follow-up study is needed to confirm these findings.

25-Hydroxyvitamin D 2↗
PubMed2006

How do bioethics teachers in Japan cope with ethical disagreement among healthcare university students in the classroom? A survey on educators in charge.

OBJECTIVE: The purpose of this study was to demonstrate how educators involved in the teaching of bioethics to healthcare university students in Japan would cope with ethical disagreement in the classroom, and to identify factors influencing them. METHODS: A cross sectional survey was conducted using self administered questionnaires mailed to a sample of university faculty in charge of bioethics curriculum for university healthcare students. RESULTS: A total of 107 usable questionnaires were returned: a response rate of 61.5%. When facing ethical disagreement in the classroom, coping behaviour differed depending on the topic of discussion, was influenced by educators' individual clear ethical attitudes regarding the topic of discussion, and was independent of many respondents' individual and social backgrounds. Among educators, it was commonly recognised that the purpose of bioethics education was to raise the level of awareness of ethical problems, to provide information about and knowledge of those issues, to raise students' sensitivity to ethical problems, and to teach students methods of reasoning and logical argument. Yet, despite this, several respondents considered the purpose of bioethics education to be to influence students about normative ethical judgments. There was no clear relationship, however, between ways of coping with ethical disagreement and educators' sense of the purpose of bioethics education. CONCLUSIONS: This descriptive study suggests that educators involved in bioethics education for healthcare university students in Japan coped in various ways with ethical disagreement. Further research concerning ethical disagreement in educational settings is needed to provide better bioethics education for healthcare students.

Adaptation, Psychological↗
PubMed2003

Finite element analysis of the stresses around fixtures in various reconstructed mandibular models--part II (effect of horizontal load).

UNLABELLED: AIM OF EXPERIMENT: Having already studied the effect of vertical load (Nagasao et al., 2002), the purpose of this study was to investigate the effect of horizontal load on implants embedded into a virtually reconstructed mandible. MATERIAL AND METHODS: Three-dimensional virtual models of various reconstructed mandibles were designed on a PC and 50 N horizontal loads were applied on the cantilever portion of the upper structure. Then, using a finite element analysis, stresses occurring around the implants were calculated, and the directions of the forces that cause the maximum von Mises stresses were evaluated. Finally, the results were compared with those from vertical loading. RESULTS: In all models, the maximum stresses occurred around the implants embedded on the premolar region of the loaded side. In addition, the locations at which the maximum von Mises stresses occurred were greatly influenced by the structural character of the loaded side. CONCLUSION: When horizontal loads were applied to reconstructed mandibles, the location and direction of the maximum stresses around the dental implants appeared to be influenced much more by the structural characters of the reconstructed mandibles when compared with vertical loads.

Bone Transplantation↗
PubMed2003

Response to preoperative chemotherapy affects prognosis in esophageal cancer.

The effect of preoperative chemotherapy on prognosis is still controversial. We have investigated the relationship between responses to preoperative chemotherapy and prognosis after curative operations in patients with esophageal squamous cell carcinoma. Thirty-nine patients received preoperative chemotherapy with continuous infusion of 500 mg/m2 of 5-fluorouracil (5-FU) and intravenous injection of 20 mg/m2 of leucovorin every 12 hours for 5 days. On the 5th day alone, 70 mg/m2 of cisplatin was also infused. The effect was evaluated approximately 14 days after the end of one course of chemotherapy. The rates of responders and non-responders were 64.1% and 35.9%, respectively. After an interval of 21-28 days, transthoracic esophagectomy was performed. Significant histological effect by chemotherapy was found in responders compared to non-responders (P < 0.05). Responders had a significantly better prognosis than non-responders by Log-rank test (P < 0.01). This suggests that preoperative chemotherapy may contribute to better prognosis when the tumor is sensitive to chemotherapy.

Adult↗
PubMed2002

Effectiveness of preoperative chemotherapy using carboplatin (CBDCA) and surgery against an esophageal small cell carcinoma.

A 63-year-old man presented to our hospital with persistent dysphagia. Radiologic and endoscopic examination disclosed a 2.0-cm exophytic tumor in the middle third of the esophagus. An endscopically obtained biopsy specimen was found to represent undifferentiated small cell carcinoma. Computed tomography of the chest, abdomen, and cervical region was performed, as were gallium and bone scintigraphy. Metastasis to an adjacent lymph node was detected, without metastasis to distant organs. After neoadjuvant chemotherapy with carboplatin (CBDCA) (400 mg/m2) and etoposide (VP-16) (100 mg/m2), endoscopy and barium-swallow esophagography showed regression. Thoracic esophagectomy then was performed with mediastinal, abdominal and cervical lymph node dissection. The resected tumor was polypoid, measuring 0.5 x 0.5 cm. The lesion consisted mainly of small anaplastic cells, but included a small focus of squamous cell carcinoma. The patient has survived for more than 7 months with no further treatment and no evidence of recurrent disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

Effects of preoperative chemotherapy on metastatic lymph nodes in esophageal squamous cell carcinoma.

The aim of this study was to evaluate the effect of preoperative chemotherapy on metastatic lymph nodes and on the outcome of patients who underwent esophagectomy for advanced squamous cell carcinoma of the esophagus. Fifty-nine patients with potentially resectable squamous cell carcinoma of the esophagus were studied. Twenty patients (group A) were treated by preoperative chemotherapy with cisplatin, 5-fluorouracil, and leucovorin, followed by surgery. Thirty-nine patients underwent surgery alone (group B). A total of 2591 resected lymph nodes were histologically evaluated for metastasis and the effect of chemotherapy. The metastasis rate in the resected lymph nodes, the number of metastatic lymph nodes, and outcome of the patients were statistically analyzed between groups. In group A, the clinical and pathological response rates were 75% and 75% respectively. The metastasis rate in the resected lymph nodes was significantly higher in group B (P < 0.01). The mean number of metastatic lymph nodes was significantly lower in group A (P < 0.05). Furthermore, the mean number of metastatic lymph nodes was significantly lower in the chemotherapy responders than in non-responders. The survival rate in group A was better than in group B (P = 0.07). Preoperative chemotherapy reduced the number of metastatic lymph nodes and may contribute to improving the outcome of the patients who have undergone esophagectomy for squamous cell carcinoma of the esophagus.

Adult↗
PubMed2002

Finite element analysis of the stresses around endosseous implants in various reconstructed mandibular models.

PURPOSE: To calculate the location and intensity of the maximum stresses occurring around implants in the reconstructed mandible. MATERIAL AND METHODS: Human preserved mandibles and fibulae were used to design 3-D mandibular models on a Desktop Computer. Various 3-D simulation models representing mandibles were made. Implants (fixtures) and superstructures were then embedded in each model and occlusal pressure was applied to the cantilever portion of the superstructure. Von Mises stress, the maximum and minimum principal stress on each model were calculated using finite element structural analysis software. Finally, evaluation of the stresses around each fixture hole was performed. RESULTS: It appeared that for each fixture hole, the direction and the magnitude of the stresses were influenced by complex factors such as the thickness of the cortical bone where the fixtures were embedded, the degree of vertical displacement under load, and the relationship between adjacent fixtures. CONCLUSION: Location and intensity of the stresses occurring around fixtures differs significantly between various types of mandibular reconstruction. Published by Elsevier Science Ltd.

Bite Force↗
PubMed2002

Genetic polymorphisms of cytochrome P450 1A1 and risk of gallbladder cancer.

The relation between cytochrome P4501A1 (CYP1A1) gene polymorphisms and the risk of gallbladder cancer was examined. To clarify individual differences in susceptibility to gallbladder carcinogenesis, we investigated the frequency of the Mspl and Ile-Val polymorphisms of the CYP1A1 gene, in 52 patients with gallbladder cancer (32 females, 20 males) and 104 healthy controls (64 females, 40 males). We then examined the relationship between the CYP1A1 polymorphisms and the development of gallbladder cancer in members of both sexes. A statistical difference in the frequencies of the MspI and Ile-Val polymorphisms or their alleles (ml, m2 and Ile, Val) was not observed in the male patients and controls. Among females, however, the frequencies of genotypes C and Ile/Val were significantly higher (p < 0.05) in the patients than in their controls. Moreover, the frequency of the hetero genotype Ile/Val was statistically higher (p < 0.05) in the female patients than in the male patients. This study demonstrated a significant over-representation of genotypes C and Ile/Val in female patients with gallbladder cancer. Females with genotypes C and/or Ile/Val may have a high genetic susceptibility to the development of gallbladder cancer.

Alleles↗
PubMed2001

Response of renal sympathetic nerve activity to parabolic flight-induced gravitational change in conscious rats.

The renal sympathetic nerve activity (RNA) response to gravitational changes induced by parabolic flight was examined in chronically instrumented conscious rats. Two types of RNA responses were found. In six out of 12 rats, the RNA did not respond during the 2 G period, but immediately fell to background levels on entry into microgravity (microG), then recovered to the 1 G control level during continued microG (shutdown obvious group). In the other six rats, the RNA increased to 158+/-13% at the end of the 2 G period, increased further to 195+/-22% on entry into microG, then gradually recovered to that seen at 1 G (shutdown obscure group). The mean arterial pressure in the shutdown obvious group was significantly higher and the heart rate tended to be higher than in the shutdown obscure group, suggesting that the baseline sympathetic tone in the shutdown obvious group was higher than in the shutdown obscure group. These results suggest that the RNA response to parabolic flight might be affected by the baseline sympathetic tone.

Animals↗
PubMed2001

Acute response of aortic nerve activity to free drop-induced microgravity in anesthetized rats.

To test the hypothesis that arterial baroreflex was stimulated during microgravity (microG), arterial pressure (AP), intrathoracic pressure (ITP), and aortic nerve activity (ANA) were measured in anesthetized rats during 4.5 s of microG produced by free drop. A smooth and immediate reduction in G occurred during free drop, microG being achieved 100 ms after the start of the drop. Acute microG elicited an immediate and striking, but transient, increase in ANA, with no significant change in the AP, but a significant decrease in the end-expiratory ITP. The calculated transmural pressure of the aorta increased by 6.9 mmHg 2 s after the start of the drop. The increase in ANA lasted 2 s, then ANA returned to the control level, despite the calculated end-expiratory transmural pressure still being high. These results suggest that microG conditions stimulate the aortic baroreceptor by increasing transmural pressure by reducing the ITP. However, this effect is only transient, probably due to the high-pass property of the baroreceptors.

Animals↗
PubMed2001

Chaotic behavior in the locomotion of Amoeba proteus.

The locomotion of Amoeba proteus has been investigated by algorithms evaluating correlation dimension and Lyapunov spectrum developed in the field of nonlinear science. It is presumed by these parameters whether the random behavior of the system is stochastic or deterministic. For the analysis of the nonlinear parameters, n-dimensional time-delayed vectors have been reconstructed from a time series of periphery and area of A. proteus images captured with a charge-coupled-device camera, which characterize its random motion. The correlation dimension analyzed has shown the random motion of A. proteus is subjected only to 3-4 macrovariables, though the system is a complex system composed of many degrees of freedom. Furthermore, the analysis of the Lyapunov spectrum has shown its largest exponent takes positive values. These results indicate the random behavior of A. proteus is chaotic and deterministic motion on an attractor with low dimension. It may be important for the elucidation of the cell locomotion to take account of nonlinear interactions among a small number of dynamics such as the sol-gel transformation, the cytoplasmic streaming, and the relating chemical reaction occurring in the cell.

Algorithms↗
PubMed2001

Intrahepatic cholangiojejunostomy for unresectable malignant biliary tumors with obstructive jaundice.

We reviewed our experience with intrahepatic cholangiojejunostomy as a palliative therapy for patients with unresectable malignant diseases involving the ductal confluence or the common hepatic duct. Fifteen patients with malignant biliary obstruction were treated by cholangiojejunostomy at our hospital. Two patients had intrahepatic cholangiocarcinoma, 7 had gallbladder carcinoma, 5 had bile duct carcionoma, and 1 had pancreatic carcinoma. Segment III cholangiojejunostomies were performed in 14 patients and segment V cholangiojejunostomy in 1. Contraindications for surgical resection were locoregional invasion of tumors involving the proper and/or common hepatic artery and portal vein in 15 patients and the presence of hepatic metastases in 6 patients. Liver metastases were detected in 5 of the 7 patients with gallbladder carcinoma. Postoperative complications occurred in 2 patients (13%), but there was no leakage of the cholangioenteric anastomosis in our series. There was no operative mortality after cholangiojejunostomy. Of the 9 patients who survived for more than 6 months after surgery, 7 showed a significant improvement in performance status (PS) (82 +/- 10%) 3 months after the surgery compared with the preoperative PS (70 +/- 7%). Four of the 9 patients had recurrent cholangitis as a late complication, but 4 were completely free from jaundice. Median survival after cholangioenteric bypass was 9 months (range, 2-25 months). With respect to tumor location, the median survival time was 4 months (range, 2-25 months) in patients with gallbladder carcinoma and 15.5 months (range, 12-22 months) in those with bile duct carcinoma. While the median survival period after surgery was only 3 months (range, 2 to 8 months) in the 5 patients with hepatic metastases from gallbladder carcinoma, 2 patients without liver metastasis survived for 9 and 25 months after segment III cholangioenteric bypass. In conclusion, cholangiojejunostomy can provide useful palliation for malignant biliary obstruction when combined with careful patient selection.

Bile Duct Neoplasms↗
PubMed2001

Change of the host immune response during the early phase of interferon therapy correlates with its long-term efficacy for chronic hepatitis C.

Host immunomodulation through T cell action may play a pivotal role in determining the response to interferon (IFN) therapy for chronic hepatitis C. We examined whether the early changes in the host immune response were helpful in predicting the final effect in 31 patients with chronic hepatitis C receiving IFN. IFN treatment significantly reduced the serum levels of intercellular adhesion molecule-1 (ICAM-1) and E-selectin, and significantly increased those of vascular cell adhesion molecule-1 (VCAM-1) and interleukin-2 receptor alpha (IL-2Ralpha) in the first 7-10 days. Serum levels of these immunological parameters did not correlate with serum alanine aminotransferase (ALT) when evaluated with either absolute values or relative values (over pre-treatment value), implying that our results are not just secondary to improvement in hepatic inflammation. The relative changes (Delta) in these parameters reflected the long-term response to IFN therapy, i.e. the lower the change, the more effective the therapy was. Among these serum parameters, DeltaIL-2Ralpha within the first 7-10 days of IFN treatment was the most useful parameter in predicting the response to therapy. In conclusion, a dynamic immunomodulation during the early phase of IFN therapy may determine the subsequent long-term response to IFN therapy.

Journal Article↗
PubMed2001

Vitamin D insufficiency in Japanese female college students: a preliminary report.

Vitamin D insufficiency, a risk factor for osteoporosis, has been well investigated in elderly women worldwide, but little information has been available for younger women. This study aimed to determine serum 25-hydroxyvitamin D [25(OH)D] levels in Japanese female college students, and to test whether there is an association between 25(OH)D and bone strength. Subjects were 77 Japanese female junior college students aged 19-24 years. Serum 25(OH)D was measured with high performance liquid chromatography. Bone strength of the calcaneus was evaluated using the osteo sono-assessment index (OSI), a combined index reflecting the bone mass, bone architecture, and elasticity, as measured by quantitative ultrasound densitometry (AOS-100, Aloka). The mean 25(OH)D concentration was 34.2 nmol/L (SD +/- 12.1). The proportion of subjects with 25(OH)D less than 30 nmol/L, a cut-off value for vitamin D insufficiency, was 31/77 (40.3%). Simple linear regression analysis showed that there was a significant linear relationship between 25(OH)D and OSI (R2 = 0.098, p = 0.0069). The association held even after adjusting for weight (partial R2 = 0.098, p = 0.0023). Body weight was also a significant predictor of OSI (partial R2 = 0.105, p = 0.0034). These results suggest that vitamin D insufficiency may be prevalent in healthy young women. Moreover, low levels of 25(OH)D in young women may adversely affect bone strength. An additional, newly designed epidemiological study with a sufficient sample size is needed to confirm the present findings.

Adult↗
PubMed2001

Long-term evaluation of extracorporeal shock-wave lithotripsy for cholesterol gallstones.

BACKGROUND: Extracorporeal shock-wave lithotripsy (ESWL) is a treatment that preserves the gallbladder. Problems after ESWL treatment include stone recurrence and the development of biliary symptoms. METHODS: Two hundred and sixty-two patients with cholesterol-type gallstones, the best indication for ESWL treatment, and 42 control patients with cholesterol-type gallstones who received no treatment entered this study. We evaluated the factors associated with recurrence of gallstones after stone clearance and the development of biliary symptoms after ESWL treatment. RESULTS: The 3-, 5- and 7-year cumulative probabilities of gallstone recurrence were 20.6, 27.1 and 33.1%, respectively, with the recurrence probability significantly lower in patients with good gallbladder contractility. In patients with recurrence, ursodeoxycholic acid (UDCA) treatment was effective. In 69 patients with residual gallstones, the 3-, 5- and 7-year cumulative risks of biliary symptoms were 17.3, 24.9 and 30.5%, respectively. With residual gallstones, the risk of biliary symptoms developing was significantly lower in patients with a < or = 3 mm fragment size at the end of ESWL treatment and in those treated consistently with UDCA for 6 months or more after treatment with ESWL. The risk of biliary symptoms was significantly lower in ESWL-treated patients with residual stones who had a < or = 3 mm fragment size after treatment compared to those of control patients. CONCLUSIONS: Ursodeoxycholic acid was effective in clearing stones in patients with gallstone recurrence. In patients with residual stones, the fragmentation of stones to < or = 3 mm and UDCA administration effectively reduced the risk of subsequent biliary symptoms.

Case-Control Studies↗
PubMed2001

Impact of repeat hepatectomy on recurrent colorectal liver metastases.

BACKGROUND: Hepatic recurrence is seen in approximately 40% of patients undergoing hepatectomy for colorectal metastases. This study was designed to assess the risks and clinical benefits of repeat hepatectomy for those patients. METHODS: Twenty-six patients underwent repeat hepatectomy for hepatic recurrence, and their clinical data were retrospectively reviewed for operative morbidity and mortality, performance level, and survival. RESULTS: There was no operative mortality after repeat hepatectomy. Operative bleeding was significantly increased in the second hepatectomy; but operating time, duration of hospital stay, and performance status after the second hepatectomy were comparable with those of the initial hepatectomy. The median survival time from the second hepatectomy was 31 months, and the 3- and 5-year survival rates were 62% and 32%, respectively. A short disease-free interval (6 months or less) between the initial hepatectomy and diagnosis of hepatic recurrence in the remnant liver was significantly associated with poor survival after the second hepatectomy. CONCLUSIONS: Repeat resection contributed to clinical benefits for selected patients with hepatic recurrence after the initial hepatectomy for colorectal liver metastases. However, appearance of hepatic recurrence within 6 months or less after the initial hepatectomy is a poor prognostic factor for repeat hepatectomy.

Adult↗
PubMed2001

Photon path distribution and optical responses of turbid media: theoretical analysis based on the microscopic Beer-Lambert law.

A concise theoretical treatment has been developed to describe the optical responses of a highly scattering inhomogeneous medium using functions of the photon path distribution (PPD). The treatment is based on the microscopic Beer-Lambert law and has been found to yield a complete set of optical responses by time- and frequency-domain measurements. The PPD is defined for possible photons having a total zigzag pathlength of l between the points of light input and detection. Such a distribution is independent of the absorption properties of the medium and can be uniquely determined for the medium under quantification. Therefore, the PPD can be calculated with an imaginary reference medium having the same optical properties as the medium under quantification except for the absence of absorption. One of the advantages of this method is that the optical responses, the total attenuation, the mean pathlength, etc are expressed by functions of the PPD and the absorption distribution.

Biophysics↗