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Biomedical subjects

N Nakamura

Publications and source records attributed to N Nakamura.

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

Treatment results and prognostic analysis of radical radiotherapy for locally advanced cancer of the uterine cervix.

This study investigated treatment results and prognostic factors in radical radiotherapy for stage IIB-IVA cervical cancer. This is a retrospective analysis of 71 patients with cancer of the uterine cervix treated radically with external beam radiotherapy and high-dose-rate intracavitary brachytherapy between June 1991 and May 2004. In 47/71 (66%) of patients' chemotherapy was combined with radiotherapy. All 71 patients were retrospectively analysed. The median follow-up time was 34.8 months. The median age was 57 years (range 26-78 years) There were 21 patients (30%) in stage IIB, 3 (4%) stage IIIA, 40 (56%) stage IIIB, and 7 (10%) stage IVA. The 5-year overall survival rate was 83.5%, 77.0%, and 42.9% for stage IIB, III, and IVA, respectively. Federation Internationale de Gynocologie et d'Obstetrique (FIGO) classification stage and pelvic and para-aortic nodal status significantly affected survival in univariate analysis, but no treatment-related factor was found to be significant in multivariate analysis. In this study para-aortic nodal status was the most important prognostic factor in the radical radiotherapy of cervical cancer.

Adenocarcinoma↗
PubMed2005

Clonally expanded T-cell populations in atomic bomb survivors do not show excess levels of chromosome instability.

Radiation-induced genomic instability has been studied primarily in cultured cells, while in vivo studies have been limited. One major obstacle for in vivo studies is the lack of reliable biomarkers that are capable of distinguishing genetic alterations induced by delayed radiation effects from those that are induced immediately after a radiation exposure. Here we describe a method to estimate cytogenetic instability in vivo using chromosomally marked clonal T-cell populations in atomic bomb survivors. The basic idea is that clonal translocations are derived from single progenitor cells that acquired an aberration, most likely after a radiation exposure, and then multiplied extensively in vivo, resulting in a large number of progeny cells that eventually comprise several percent of the total lymphocyte population. Therefore, if chromosome instability began to operate soon after a radiation exposure, an elevated frequency of additional but solitary chromosome aberrations in clonal cell populations would be expected. In the present study, six additional translocations were found among 936 clonal cells examined with the G-band method (0.6%); the corresponding value with multicolor FISH analysis was 1.2% (4/333). Since these frequencies were no higher than 1.2% (219/17,878 cells), the mean translocation frequency observed in control subjects using the G-band method, it is concluded that chromosome instabilities that could give rise to an increased frequency of persisting, exchange-type aberrations were not commonly generated by radiation exposure.

Breast Neoplasms↗
PubMed2005

[Pulmonary thromboembolism after thoracoscopic pulmonary wedge resection; report of a case].

We encountered a case of acute pulmonary embolism after lung cancer surgery. The case was a 64-year-old female. She was admitted to our hospital with an abnormal shadow on chest X-ray. There was a past history of hypopituitarism medicated with steroids. Chest computed tomography (CT) demonstrated ground glass attenuation shadow measuring 10 mm in the left upper lobe. She underwent left thoracoscopic pulmonary wedge resection due to bronchioloalveolar cell carcinoma. Postoperatively, the patient suddenly complained of chest pain and dyspnea the day after surgery. Chest CT showed left and right pulmonary arterial thromboembolism. Thrombolytic and anticoagulation therapy with urokinase and heparin sodium were immediately started. Venography demonstrated thrombus located in the vein of the bilateral lower leg region. We inserted an inferior vena cava filter to prevent aggravation of pulmonary embolism. After 11 days, CT showed completed thrombolysis in the bilateral pulmonary artery. The patient was discharged on the 25th postoperative day, and has been followed with anticoagulation therapy.

Acute Disease↗
PubMed2004

A single treatment with microcapsules containing a CXCR4 antagonist suppresses pulmonary metastasis of murine melanoma.

Biodegradable poly D,L-lactic acid (PLA, molecular weight: ca. 5000) microcapsules containing a CXCR4 antagonist (4F-benzoyl-TE14011) were prepared (4F-benzoyl-TE14011-PLA), and their anti-metastatic activity was evaluated in mice. A single subcutaneous administration of 4F-benzoyl-TE14011-PLA significantly reduced the number of colonies formed by pulmonary metastasis of B16-BL6 melanoma cells expressing CXCR4. The same dose of 4F-benzoyl-TE14011 in a single or a series of treatments affected little. The substance 4F-benzoyl-TE14011 dose-dependently suppressed B16-BL6 cell growth. In the cells cultured with SDF-1, a more potent suppression was observed. 4F-Benzoyl-TE14011 was rapidly released from 4F-benzoyl-TE14011-PLA for an initial period, both in vitro and in vivo. A steady release was thereafter observed. Therefore, this drug release profile might contribute to prevention of melanoma metastasis at the steps involving the migration and cell growth. These results also show that a sustained drug release formulation could be a useful drug delivery system for CXCR4 antagonists.

Animals↗
PubMed2004

Use of donor aorta for arterial reconstruction in paediatric liver and multivisceral transplantation.

BACKGROUND: Arterial reconstruction remains the most important technical issue in paediatric transplantation. The arteries of paediatric donors as well as recipients are small and friable. The aim of this study was to assess the use of the donor aorta as a conduit for arterial reconstruction in paediatric liver and multivisceral transplantation. METHODS: Between June 1994 and January 2002, 284 paediatric transplants, including 197 cadaveric liver and multivisceral transplants, were performed in children at this centre. Of these, 41 (20.8 per cent), including nine cadaveric liver transplants and 32 multivisceral transplants, were revascularized by donor aortic reconstruction. Patient demographics, types of donor arterial reconstruction, technical complications and incidence of hepatic artery thrombosis were reviewed. RESULTS: None of the 41 donor aortic reconstructions used in revascularization of paediatric liver and multivisceral transplants thrombosed. There were no bleeding complications and no pseudoaneurysms developed. CONCLUSION: Arterial reconstruction using donor aorta is a useful option with a low incidence of thrombosis in paediatric transplantation.

Aorta↗
PubMed2004

Midkine induced growth of ameloblastoma through MAPK and Akt pathways.

Midkine (MK) is expressed during tooth development and, since ameloblastoma is thought to be arisen from the epithelium of the odontogenic apparatus or its remnant tissues, the effect of MK in ameloblastoma cell growth should be examined. The expression and function of MK were examined using 37 ameloblastoma tissues and AM-1 cells, an HPV-16DNA transfected ameloblastoma cell line. We found that MK was immunohistochemically expressed in 70% of ameloblastoma cases and AM-1 cells. By stimulation with 100 ng/ml MK, the growth of AM-1 cells was accelerated two fold by the 9th day. MK could induce phosphorylation of p44/42 MAPK (Thr202/Tyr204) and Akt (Ser473 and Thr308), and by pretreatment of PD98059, MEK1 inhibitor, or LY294002, PI3K inhibitor, MK-stimulated-phosphorylation of MAPK and Akt and MK-stimulated growth of AM-1 cells were inhibited. These results suggested that MK induced growth of ameloblastoma is through the MAPK and Akt pathways.

Ameloblastoma↗
PubMed2004

Determination of elastic, anelastic, and piezoelectric coefficients of piezoelectric materials from a single specimen by acoustic resonance spectroscopy.

We describe an advanced methodology to determine all the independent elastic-stiffness coefficients Cijkl, the associated internal frictions Qijkl(-1), and piezoelectric coefficients eijk of piezoelectric materials from a single monocrystal specimen using resonant-ultrasound spectroscopy with laser-Doppler interferometry. The mechanical-resonance frequencies of a piezoelectric solid depend on all of the elastic and piezoelectric coefficients, and their accurate measurement allows one to determine the elastic and piezoelectric coefficients simultaneously. Resonance-peak-width measurements yield the internal-friction tensor. Successful determination requires correct vibration-mode identification for the observed resonance frequencies. This is achieved unambiguously by measuring deformation distributions on the vibrating-specimen surface with laser-Doppler interferometry and comparing them with calculated displacement distributions. The methodology is applied to lithium niobate (LiNbO3) and langasite (La3Ga5SiO14) crystals.

Journal Article↗
PubMed2004

Endoscopic removal of a dental implant displaced into the maxillary sinus: technical note.

Minimal invasive endoscopic surgery has been developed for various indications in the cranio-maxillofacial area. In this article, a technique for endoscopic removal of a dental implant displaced into the maxillary sinus is presented. Access to the implant was achieved transorally via the canine fossa. The implant was captured and removed using a urological retrieval basket through the endoscopic working channel port. The endoscopic surgical approach described was reliable and minimally invasive for removing dental materials displaced into the maxillary sinus.

Adult↗
PubMed2004

Characterization of dental epithelial progenitor cells derived from cervical-loop epithelium in a rat lower incisor.

Dental epithelial progenitor cells differentiate into various cell types during development of tooth germs. To study this mechanism, we produced immortalized dental epithelial progenitor cells derived from the cervical-loop epithelium of a rat lower incisor. The expression patterns of cytokeratin 14, nerve growth factor receptor p75, amelogenin, Notch2, and alkaline phosphatase were examined by immunohistochemistry in both lower and higher cell densities. The patterns of each were compared in the dental epithelium of rat lower incisors. The results demonstrated that these cells could produce ameloblast lineage cells, stratum intermedium cells, stellate reticulum, and outer enamel epithelium. Furthermore, fibroblast growth factor 10 stimulated proliferation of dental progenitor cells and subsequently increased the number of cells expressing alkaline phosphatase. These results suggest that fibroblast growth factor 10 plays a role in coupling mitogenesis of the cervical-loop cells and the production of stratum intermedium cells in rat incisors.

Alkaline Phosphatase↗
PubMed2004

Human fetuses do not register chromosome damage inflicted by radiation exposure in lymphoid precursor cells except for a small but significant effect at low doses.

Human fetuses are thought to be highly sensitive to radiation exposure because diagnostic low-dose X rays have been suggested to increase the risk of childhood leukemia. However, animal studies generally have not demonstrated a high radiosensitivity of fetuses, and the underlying causes for the discrepancy remain unidentified. We examined atomic bomb survivors exposed in utero for translocation frequencies in blood lymphocytes at 40 years of age. Contrary to our expectation of a greater radiosensitivity in fetuses than in adults, the frequency did not increase with dose except for a small increase (less than 1%) at doses below 0.1 Sv, which was statistically significant. We interpret the results as indicating that fetal lymphoid precursor cells comprise two subpopulations. One is small in number, sensitive to the induction of both translocations and cell killing, but rapidly diminishing above 50 mSv. The other is the major fraction but is insensitive to registering damage expressed as chromosome aberrations. Our results provide a biological basis for resolving the long-standing controversy that a substantial risk of childhood leukemia is implicated in human fetuses exposed to low-dose X rays whereas animal studies involving mainly high-dose exposures generally do not confirm it.

Chromosome Aberrations↗
PubMed2004

Estimating the number of hematopoietic or lymphoid stem cells giving rise to clonal chromosome aberrations in blood T lymphocytes.

Quantifying the proliferative capacity of long-term hematopoietic stem cells in humans is important for bone marrow transplantation and gene therapy. Obtaining appropriate data is difficult, however, because the experimental tools are limited. We hypothesized that tracking clonal descendants originating from hematopoietic stem cells would be possible if we used clonal chromosome aberrations as unique tags of individual hematopoietic stem cells in vivo. Using FISH, we screened 500 blood T lymphocytes from each of 513 atomic bomb survivors and detected 96 clones composed of at least three cells with identical aberrations. The number of clones was inversely related to their population size, which we interpreted to mean that the progenitor cells were heterogeneous in the number of progeny that they could produce. The absolute number of progenitor cells contributing to the formation of the observed clones was estimated as about two in an unexposed individual. Further, scrutiny of ten clones revealed that lymphocyte clones could originate roughly equally from hematopoietic stem cells or from mature T lymphocytes, thereby suggesting that the estimated two progenitor cells are shared as one hematopoietic stem cell and one mature T cell. Our model predicts that one out of ten people bears a non- aberrant clone comprising >10% of the total lymphocytes, which indicates that clonal expansions are common and probably are not health-threatening.

Adolescent↗
PubMed2004

Prediction of clonal chromosome aberration frequency in human blood lymphocytes.

We recently conducted a large-scale screening for clonal aberrations among atomic bomb survivors and proposed a model for the gross clonal composition of blood lymphocytes. Here we show an application of the model indicating that the number, m,of clones detectable by cytogenetic methods in an individual is predictable by the equation m= (1.8 + 6.4FG) x FP x n/500, where FG represents the estimated translocation frequency in the 46 chromosome set, FP is the observed translocation frequency with FISH or other methods, and nis the number of cells examined. Application of the equation to the results of seven other reports gave close agreement between the observed and calculated numbers of clones. Since the model assumes that clonal expansion is ubiquitous, and any translocation can be the constituent of a clone detectable by cytogenetic means, the vast majority of observed clonal expansions of these somatic cells are likely the result of random-hit events that are not detrimental to human health. Furthermore, since our model can predict the majority of clonal aberrations among Chernobyl workers who were examined 5-6 years after irradiation, clonal expansion seems to occur primarily within a few years after exposure to radiation, most likely being coupled with the process of recovery from radiation-induced injury in the lymphoid and hematopoietic systems.

Chromosome Aberrations↗
PubMed2004

Outcomes of kidney transplants from non-heart-beating deceased donors as reported to the Japan Organ Transplant Network from April 1995-December 2003: a multi-center report.

Between April 1995-December 2003, 1,324 deceased donor kidney transplantations were performed in 139 transplant institutes in Japan. Of these, 45 transplants were from heart-beating and 1,279 transplants were from non-heart-beating deceased donors (NHBDD). Clinical outcomes for the 1,279 recipients of NHBDD kidney transplants were investigated. The overall 5-year patient and graft survival rates were 90% and 72%, respectively. A total of 112 NHBDD kidney grafts never functioned after transplantation and the recipients had to remain on dialysis. The causes of nonfunction were rejection, primary nonfunction, death, thrombosis and others in the order of the incidence. The major causes of graft loss were nonfunction, death, chronic rejection and acute rejection in that order. Major causes of recipient deaths were pneumonia, sepsis and CVA within 12 months, and heart diseases, sepsis, malignancy and pneumonia more than 12 months after transplantation. Kidneys from female donors, donors aged 15 or less or over age 60, donors with extrinsic causes of death other than head trauma, recipients over age 60 and those with diabetic nephropathy as their original disease were found to be at risk for poor graft survival. The lowest and last donor serum creatinine level did not influence the incidence of nonfunction or graft survival. However, graft survival was significantly poorer among recipients of older "expanded" donor kidneys than for recipients of younger grafts. The warm and total ischemia times should be kept shorter than 30 minutes (better 15 minutes), and 12 hours, respectively to minimize the incidence of nonfunction and early graft loss. It is especially important in cases with WIT over 30 minutes that the total ischemia should be kept within 12 hours. Cannulation before cardiac standstill was important to reduce the incidence of nonfunction and achieve high graft survival rates with NHBDD kidneys. The discontinuance of ventilator support also reduced the incidence of graft nonfunction. The combination of CsA or Tacrolimus and MMF as both the induction and maintenance regimen significantly improved graft survival. The use of either anti-T cell antibodies or basiliximab was also associated with significantly better graft survival for NHBDD kidneys. The combination of basiliximab, CsA and MMF resulted in a graft survival rate of 98% at one and 2 years.

Adolescent↗
PubMed2003

Conservative treatment for rugby football players with an acute isolated posterior cruciate ligament injury.

We investigated the outcome of the conservative treatment from the point of athletic performance for rugby football players with an acute isolated PCL injury. The subjects were sixteen competitive rugby football players, with an average age of 21 years. After exercise consisting of quadriceps muscle strengthening and range of knee motion, the players were allowed to return to sports activity when swelling and pain disappeared. At one year after the injury, the period of return to pre-injury level and the self-evaluation for eleven performances during rugby football were surveyed by a questionnaire. Each performance of the athletic skills was rated as normal, nearly normal, abnormal or severely abnormal. Fourteen players (88%) returned to their pre-injury level. The time to return to pre-injury level ranged from one to seven months, with a mean of three months. High-speed running was the most affected skill (9 out of 14, 64%). These results showed that performance of athletic skills was apparently affected in rugby football players with an acute isolated PCL injury though the conservative treatment was effective

Adolescent↗
PubMed2003

Comparison between the cross-sectional area of bone-patellar tendon-bone grafts and multistranded hamstring tendon grafts obtained from the same patients.

This study intraoperatively compared the cross-sectional area (CSA) and graft-tunnel fit of bone-patellar tendon-bone (BTB) and multistranded hamstring tendon (STG) grafts harvested from the same patient. Twenty-two patients with a mean age of 26 years were the subjects of the study. Each BTB graft was harvested from the central third of the patellar tendon. Tripled or quadrupled semitendinosus tendon with or without gracilis tendon was used as a STG graft. CSAs of both grafts in the same patients were intraoperatively measured using a custom-made area micrometer during primary ACL reconstruction and revision surgery or during combined ACL and PCL reconstruction. Graft-tunnel fit was calculated by dividing the CSA of the graft by that of the tibial bone tunnel. The average CSA of STG grafts was significantly greater than that of BTB grafts. The average value of graft-tunnel fit for the STG grafts% was also greater than that of the BTB grafts%. Thus STG grafts have a larger CSA and closer graft-tunnel fit than BTB grafts in a clinical setting.

Adolescent↗
PubMed2003

Effects of cilostazol on serum lipid concentrations and plasma fatty acid composition in type 2 diabetic patients with peripheral vascular disease.

Cilostazol is an anti-thrombotic and vasodilating agent, reported to have both anti-thrombotic and cerebral vasodilating effects. We investigated the effects of cilostazol on serum lipid concentrations and plasma fatty acid composition in type 2 diabetic patients with peripheral vascular disease. The serum concentrations of total cholesterol, triglycerides, high-density lipoprotein-cholesterol, lipoprotein (a), remnant-like particles-cholesterol, apolipoproteins, and plasma fatty acid composition were measured in 17 diabetic patients with peripheral vascular disease before and 1, 3, and 6 months after administration of cilostazol (200 mg/day). Serum triglyceride concentrations were significantly decreased after cilostazol (from 1.31+/-0.17 mmol/l to 0.86+/-0.07 mmol/l at 6 months, P<0.01). Plasma docosahexaenoic acid levels were significantly increased after cilostazol (4.11+/-0.26% to 4.94+/-0.26% at 6 months, P<0.01). Our findings show that cilostazol can induce some beneficial changes in serum lipid profile and plasma fatty acid composition.

Aged↗