Search PubMed⌕ Search

Biomedical subjects

K Matsuo

Publications and source records attributed to K Matsuo.

At least 37 records · Page 2Linked to original sources
PubMed2005

Cyclic motion of the soft palate in feeding.

The soft palate moves rhythmically during feeding, but the timing and frequency of this motion are not known. We tested the hypothesis that cyclic soft palate motion is temporally linked to cyclic jaw movement. Nine healthy, asymptomatic human subjects with normal dentition ate solid food coated with barium. Videofluorographic recordings showed that rhythmic motions of the soft palate during mastication were linked temporally to jaw motion. Soft palate motion occurred in every recording but not in every jaw cycle. The soft palate moved upward as the jaw opened, but the nasopharynx was not sealed. During swallowing, however, the soft palate invariably elevated during the intercuspal phase of jaw motion, sealing the nasopharynx. The frequency of soft palate cycles was lowest early in a feeding sequence and gradually increased as the sequence progressed from ingestion to swallowing. We conclude that cyclic movement of the soft palate in feeding is temporally linked to jaw motion.

Adult↗
PubMed2005

Enabling on-demand real-time functional MRI analysis using grid technology.

OBJECTIVES: The analysis of brain imaging data such as functional MRI often requires considerable computing resources, which in most cases are not readily available in many medical imaging facilities. This lack of computing power makes it difficult for researchers and medical practitioners alike to perform on-site analysis of the generated data. This paper presents a system that is capable of analyzing functional MRI data in real time with results available within seconds after data acquisition. METHODS: The system employs remote computational servers to provide the necessary computing power. System integration is accomplished by an accompanying software package, which includes fMRI analysis tools, data transfer routines, and an easy-to-use graphical user interface. The remote analysis is transparent to the user as if all computations are performed locally. RESULTS: The use of PC clusters in the analysis of fMRI data significantly improved the performance of the system. Simulation runs fully achieved real-time performance with a total processing time of 1.089 s per image volume (64 x 64 x 30 in size), much less than the per volume acquisition time set to 3.0 s. CONCLUSIONS: The results show the feasibility of using remote computational resources to enable on-demand real-time fMRI capabilities to imaging sites. It also offers the possibility of doing more intensive analysis even if the imaging site doesn't have the necessary computing resources.

Brain↗
PubMed2004

Normal mineralization and nanostructure of sclerotic bone in mice overexpressing Fra-1.

Increased bone mass due to elevated number of active osteoblasts has been reported for transgenic mice overexpressing the transcription factor Fra-1. To explore the potential of the anabolic action of Fra-1 in treatment of osteoporosis, we examined the integrity of bone matrix generated in Fra-1 transgenic mice. Femora from Fra-1 transgenic (Fra-1 tg) and wild-type littermates were analyzed for bone mineralization density distribution (BMDD) and nanostructure using quantitative backscattered electron imaging (qBEI) and scanning small angle X-ray scattering (scanning-SAXS), respectively. For comparison, we studied mice lacking c-Fos (Fos-/-), which develop osteopetrosis because of the absence of osteoclasts. Morphometrical analysis of metaphyseal spongiosa revealed an up to 5-fold increase in bone volume for Fra-1 transgenic compared to wild type. BMDD indicated a transient lower mineralization of bone for Fra-1 transgenic at 5 and 8 weeks, which became comparable to that of wild-type mice by 8 months. The homogeneity of mineralization was not altered in the Fra-1 transgenic mice at any ages examined. However, it was strikingly reduced in Fos-/- due to an abundance of hypermineralized cartilage. The bone nanostructure did not show abnormalities in Fra-1 transgenic or Fos-/-. These results provide a rationale for the development of therapeutic applications involving Fra-1-induced bone formation.

Animals↗
PubMed2004

Remaining caudate lobe in the right lobe graft in living donor liver transplantation: a blind spot?

The right margin of the caudate lobe is obscure. Therefore, a part of the caudate lobe (a part of the right side of the paracaval portion) seems almost always to remain with the right lobe graft during the standard harvesting procedure. We reviewed the intraoperative findings and the postoperative courses of donors and recipients of 11 consecutive living donor liver transplantations using right lobe grafts. Further, we used computed tomography during the postoperative course to investigate whether the remaining caudate lobe was present in the right lobe graft and whether it produced serious complications. Four recipients displayed an intraoperative bile leak from a remaining part of the caudate lobe after the completion of biliary reconstruction. With the exception of one case who developed repeated bile leakage from the same origin which eventually healed during a long-term postoperative course, Most recipients showed no postoperative biliary complications. Although a remaining caudate lobe was detected on postoperative computed tomography in all recipients, it produced no serious complications. In conclusion, a part of the right side of the paracaval portion of the caudate lobe almost always remains with a right lobe graft during the standard harvesting procedure. However, the implications of this phenomenon seem to be benign.

Adult↗
PubMed2004

Usefulness of artificial liver support for pretransplant patients with fulminant hepatic failure.

This study assessed the usefulness of artificial liver support (ALS) for pretransplant patients with fulminant hepatic failure (FHF). Five patients (age 14 to 52 years, 3 men and 2 women) with FHF who were being prepared for living donor liver transplantation (LDLTx) were enrolled in this study. ALS included plasma exchange, using 40 to 50 units of fresh frozen plasma per session, and high-flow hemodiafiltration, using a high-performance polysulfone membrane. Variables such as circulatory and respiratory function, coma grade, and neurologic disorders were evaluated. Although systolic and diastolic blood pressures showed no statistical differences between pre-ALS and post-ALS, the difference in heart rates was statistically significant. After ALS initiation in the pre-LDLTx period, one of the three patients who needed mechanical ventilation was weaned from it. After LDLTx, all patients recovered neurologically; no neurologic disorder was observed. These results suggested that ALS could predict neurologic status after LDLTx. The difference in coma grades also achieved statistical significance. Our study indicates that short-term ALS is useful for improving circulatory and respiratory function prior to liver transplantation, as well as for predicting posttransplantation neurologic status. Although some patients recover by ALS alone, the survival rate of ALS-only patients is less than 50%. ALS prolongs intensive treatment, thus increasing both the risk of infection and the medical costs. Further investigation to determine a precise marker for liver regeneration will be needed to establish a consensus on the indications for long-term ALS. We conclude that ALS is useful to improve circulatory and respiratory functions among pretransplant patients, and to predict neurologic status after LDLTx.

Adolescent↗
PubMed2004

Usefulness of the prognostic score for donor safety in living donor liver transplantation.

This study sought to determine whether a prognostic score is a useful indicator of donor safety using 13 consecutive donors enrolled for liver transplantation. The donor operations were right hepatic lobectomies (n = 10) and left hepatic lobectomies (n = 3). The postoperative maximal level of serum total bilirubin was used to assess the magnitude of surgical stress. Variables such as donor age, percentage of liver resection (PLR), indocyanine green 15-minute retention rate (ICGR15), operative blood loss, operation time, prognostic score and graft weight were evaluated as predictors of the magnitude of surgical stress. The PLR and prognostic score (PS) were calculated according to the following formulae: PLR (%) = 100*Graft weight (g)/standard liver volume of the donor (mL); PS = -84.6 + 0.933*PLR (%) +1.11*ICGR15 (%) +0.999*age (years); Standard liver volume (mL) = 706.2*body surface area (m2) + 2.39. No serious complications occurred after the donor operations. Maximal bilirubin ranged from 1.9 to 10.9 mg/dL. There were no mortalities, although there were two morbidities, bile leakage and prolonged liver dysfunction. Postoperative hyperbilirubinemia was observed in two donors and in one Gilbert's syndrome donor. Linear regression analysis of each variable indicated poor correlations between those variables and maximal bilirubin. However, close correlations were seen between maximal bilirubin and both donor age and PS except for the three patients who showed postoperative hyperbilirubinemia. In these uneventful donors, statistical formulae were obtained as follows: maximal bilirubin (PMB) = 0.271 + 0.056*donor age (correlation coefficient 0.612, P < .008), PMB = 1.541 + 0.059*PS (correlation coefficient 0.597, P < .009). In conclusion, PS is useful to predict maximal bilirubin and to ensure donor safety.

Age Factors↗
PubMed2004

Surveillance of perioperative infections after adult living donor liver transplantation.

AIM: This study was conducted to clarify the management of perioperative infectious complications after adult living donor liver transplantation (LDLT). PATIENTS AND METHODS: Fourteen adult LDLT patients were enrolled in this study. We examined the occurrence of infectious complications in these cases and the relationships of infectious complications to UNOS status and MELD score. Surveillance culture and immunoserologic analyses were performed. From the results of these analyses, we made a diagram of infection surveillance using a matrix of time and sampling site. Using the diagram, we chose sensitive antibiotics as soon as possible. RESULTS: The infection site and its pathogen were able to be detected in four (28.5%) patients, all of whom had MRSA infections, together with lung aspergillosis in one case, pseudomonas pneumonia in another, and both in another. Two patients died of lung aspergillosis. Bacteria detected in the airway tended to spread to other sites during the postoperative period. In all four patients in whom infectious diseases were detected, and in a fifth patient in whom the site of infection was not known, the UNOS status was 1. The MELD score was calculated in eight patients, six of whom had high MELD scores (>20). CONCLUSION: Most cases were manageable by choosing and changing antibiotics and antifungal drugs according to the results of surveillance cultures twice a week. However, aspergillosis had an extremely poor prognosis. Patients with a high MELD score or low UNOS status, or both, showed poor prognosis; and in them, multiple drug resistance bacteria caused severe perioperative infectious complications.

Adult↗
PubMed2004

Clinical impact of graft-versus-host disease against leukemias not in remission at the time of allogeneic hematopoietic stem cell transplantation from related donors. The Japan Society for Hematopoietic Cell Transplantation Working Party.

Acute graft-versus-host disease (GVHD) increases post-transplant mortality and morbidity, but exerts a potent graft-versus-leukemia (GVL) effect. To clarify the impact of GVHD on outcome after transplant in aggressive diseases, patients with acute myeloid or lymphoblastic leukemia (AML, n = 366 or ALL, n = 255) in nonremission states, or chronic myelogenous leukemia (CML, n = 180) in accelerated phase (AP) or blastic crisis (BC), who received allogeneic hematopoietic stem cell transplantation (HSCT) from a related donor between 1991 and 2000, were analyzed. Significant improvement in overall and disease-free survival (DFS) was detected with grade I acute GVHD in AML (P = 0.0002 for overall survival and 0.0009 for DFS, respectively) and in CML (P = 0.0256 and 0.0366, respectively), while the trend towards improved survival was observed in ALL. Relapse rate was lower in grade I acute GVHD than in grade II in all three diseases, suggesting that treatment for grade II GVHD may compromise the GVL effect associated with GVHD. Chronic GVHD was found to suppress relapse in CML and ALL, but not in AML, although no improvement in survival was observed in any disease category. Our results suggest that treatment for grade II acute GVHD may need to be attenuated in transplant for refractory leukemias.

Adolescent↗
PubMed2004

Addition of platinum compounds to a new agent in patients with advanced non-small-cell lung cancer: a literature based meta-analysis of randomised trials.

BACKGROUND: Single new agents reportedly produce promising response and survival effects, but platinum-based doublets remain the standard chemotherapy for advanced non-small-cell lung cancer (NSCLC). The aim of this study was to evaluate the effectiveness of platinum for advanced NSCLC by carrying out a meta-analysis of trials that compared platinum-based doublets with single new agent therapy alone. METHODS: We carried out a literature search to identify trials, conducted between 1994 and 2003, comparing a doublet of platinum plus a new agent with a new agent alone in previously untreated patients with advanced NSCLC. Outcomes analysed were response, survival and toxicity. RESULTS: Eight trials encompassing 2374 patients were identified. Platinum-based doublets produced an approximately two-fold higher overall (complete and partial) response rate than the new agent alone [odds ratio = 2.32; 95% confidence interval (CI)=1.68-3.20]. Platinum-based doublet therapy was also associated with a 13% prolongation of survival (hazard ratio = 0.87; 95% CI = 0.80-0.94, P <0.001). Despite significant increases in the frequencies of various toxic effects in patients receiving platinum-based doublets, no significant difference in treatment-related mortality was observed. CONCLUSION: This is the first published meta-analysis demonstrating the importance of combining platinum with single new agents in the treatment of advanced NSCLC.

Antineoplastic Agents↗
PubMed2004

A malar granular cell tumor in a djungarian hamster.

'Granular cell' tumor observed in the malar subcutis of a Djungarian hamster was examined to determine its cellular origin. Histologically, the tumor consisted of a solid growth of oval or spindle-shaped large cells with abundant cytoplasm filled with eosinophilic granules that were periodic acid-Schiff-positive and diastase-resistant. Immunohistochemically, the tumor cells were positive to anti-vimentin and anti-desmin antibodies and a few cells showed positivity to anti-actin antibody as well. They did not react to myoglobin, S-100 protein, and glial fibrillary acidic protein (GFAP). Electron microscopic studies revealed that the tumor cells had pinocytotic vesicles, dense plaque and microfilaments. The first granular cell variant of myogenic tumor reported here in Djungarian hamsters was differentiated from granular cell tumor of Schwann cell origin.

Animals↗
PubMed2004

In situ expression of RANKL, RANK, osteoprotegerin and cytokines in osteoclasts of rat periodontal tissue.

OBJECTIVES: This study examined the in situ expression of receptor activator of nuclear factor-kappaB ligand (RANKL), receptor activator of nuclear factor-kappaB (RANK), osteoprotegerin, interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) in the osteoclasts of rat periodontal tissue. BACKGROUND: In periodontal disease, osteoclasts cause resorption of the alveolar bone. The function of osteoclasts is regulated by interaction with periodontal ligament cells (PDLs). Furthermore, various kinds of molecules such as RANKL, RANK, osteoprotegerin, IL-1beta and TNFalpha are known to be related to the osteoclasts differentiation and function. It is therefore important to observe the expression of RANKL, RANK, osteoprotegerin and cytokines in osteoclasts and PDLs. METHODS: Four-week-old Wistar rats were used. Tooth movement was performed by the Waldo method, and the pathological bone resorption was induced. The demineralized maxillae and mandiblae were embedded with paraffin. In situ hybridization was performed to detect RANKL, RANK, osteoprotegerin, IL-1beta, and TNFalpha mRNAs in osteoclasts and other cells using the specific RNA probes, respectively. RESULTS: Both RANKL and RANK were concomitantly expressed in some osteoclasts. RANKL was also positive in osteoblasts and PDLs. No IL-1beta- and TNFalpha-positive osteoclast was noted. The positive signals of osteoprotegerin were detected in almost all osteoblasts, PDLs and odontoblasts. No osteoprotegerin-positive osteoclasts were observed. The number and the distribution pattern of RANKL- and RANK-expressing osteoclasts changed when orthodontic excessive force was applied to periodontal tissue. In addition, IL-1beta and TNFalpha were shown to be expressed in osteoclasts under pathological status. CONCLUSION: These findings suggest that an autocrine mechanism of RANKL-RANK exists in osteoclast, which is heightened in the pathological conditions. Furthermore, the autocrine mechanism of IL-1beta and TNFalpha is also provided in osteoclast under pathological condition. These autocrine mechanisms therefore seem to regulate the osteoclast function in both physiological and pathological conditions.

Animals↗
PubMed2003

Protection of trocar sites from gallbladder cancer implantation by sodium hyaluronate carboxymethylcellulose-based bioresorbable membrane (Seprafilm) in a murine model [corrected].

BACKGROUND: The risk of port site metastasis in laparoscopic surgery for cancer patients is a problem that has yet to be resolved. We examined the protective effect of a sodium hyaluronate-based bioresorbable membrane (Seprafilm) on tumor cell implantation at laparoscopic trocar sites. METHODS: Four 2-mm trocar sites were created in nude mice, and the peritoneal wounds were covered with different-sized pieces of Seprafilm. The protective effect of Seprafilm on the implantation of GB-d1 (a human gallbladder cancer cell line) at the trocar sites was assessed after 7 days. In addition, the effects of sodium hyaluronate and Seprafilm on the growth and motility of GB-d1 were examined in vitro. RESULTS: Seprafilm significantly decreased the incidence of implantation compared with the control group. Histologically, Seprafilm was observed on days 1 and 3, as a sheet of gel that covered the injured peritoneum and muscle layer. In an invasion assay using Seprafilm, no cells were found to infiltrate through the gel sheet. CONCLUSION: Seprafilm protects peritoneal wounds by physically covering the injured peritoneum. Therefore, if Seprafilm were attached to the injured peritoneum after laparoscopic surgery for cancer patients, it might reduce port site metastasis.

Adenocarcinoma↗
PubMed2003

Estimation of general linear model coefficients for real-time application.

An algorithm using an orthogonalization procedure to estimate the coefficients of general linear models (GLM) for functional magnetic resonance imaging (fMRI) calculations is described. The idea is to convert the basis functions or explanatory variables of a GLM into orthogonal functions using the usual Gram-Schmidt orthogonalization procedure. The coefficients associated with the orthogonal functions, henceforth referred to as auxiliary coefficients, are then easily estimated by applying the orthogonality condition. The original GLM coefficients are computed from these estimates. With this formulation, the estimates can be updated when new image data become available, making the approach applicable for real-time estimation. Since the contribution of each image data is immediately incorporated into the estimated values, storing the data in memory during the estimation process becomes unnecessary, minimizing the memory requirements of the estimation process. By employing Cholesky decomposition, the algorithm is a factor of two faster than the standard recursive least-squares approach. Results of the analysis of an fMRI study using this approach showed the algorithm's potential for real-time application.

Algorithms↗
PubMed2003

Persistent infection of Mongolian jirds with a non-pathogenic trypanosome, Trypanosoma (Herpetosoma) grosi.

Non-pathogenic trypanosomes of the subgenus Herpetosoma are normally host specific, and laboratory models include Trypanosoma lewisi in rats and Trypanosoma musculi in mice. Two isolates of Trypanosoma grosi, originating from Apodemus agrarius and Apodemus peninsulae, grew well in Mongolian jirds, Meriones unguiculatus, after intraperitoneal inoculation of 2 x 10(5) or a minimum 500 bloodstream forms. The course of T. grosi infection in jirds resembled T. musculi infection in mice, rather than T. lewisi infection in rats. At week 2 to 3 p.i. trypanosomes disappeared from the bloodstream, and neither prednisolone treatment nor splenectomy prevented parasite elimination from the bloodstream. However, these treatments induced a marked increase in peak parasite counts. Regardless of prednisolone treatment or splenectomy, all jirds after day 21 p.i. became resistant to the reinfection. Although no trypanosomes were detected in the bloodstream of recovered jirds, dividing parasites persisted in the medullary capillaries of the kidney, like T. musculi infection in mice. We propose the T. grosi infection in jirds as an additional laboratory model for the study of non-pathogenic trypanosomes.

Animals↗