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Biomedical subjects

T Nakajima

Publications and source records attributed to T Nakajima.

At least 181 records · Page 10Linked to original sources
PubMed2001

Web-based educational tool for cleft lip repair using XVL.

Recent web-based technologies have brought a variety of new possibilities to the field of medical information. Nevertheless, transferring 3D patient models through usual low-band-width networks is difficult because of the large size of data file. XVL (eXtensive VRML with Lattice), a new framework for 3D Data representation with high quality surface shape, has solved this problem. In cooperation with Lattice Technology Inc., we have created XVL-formatted patient 3D models. The XVL model takes less than 100 kilobytes, whereas the same quality model in Virtual Reality Modeling Language(VRML) format requires more than 5 megabytes. Because of the many advantages of XVL, we have created a 3D web-based educational tool for repair of cleft lip--plastic surgery for congenital defects of the lips that requires complex incisions and reconstruction. Our system can interact with the model and 3D visualization of the incision lines, displacement of skin flaps, and suturing. Our educational tool for cleft lip repair has demonstrated that the XVL model and its web-based application can open up new possibilities for 3D medical information systems. We are currently refining the XVL model and developing XVL-based applications to simulate the actual surgery on the World Wide Web.

Cleft Lip↗
PubMed2001

[A case of retroperitoneal malignant fibrous histiocytoma with marked response to cisplatin, ifosfamide and doxorubicin].

A 61-year-old man was admitted to our hospital in December 1994 for a suspected retroperitoneal tumor. Systemic imaging investigations demonstrated retroperitoneal solid tumor, which was diagnosed as malignant fibrous histiocytoma (MFH) by immunohistochemistry for alpha 1-antitrypsin. In March 1995, he was treated with 3 courses of systemic chemotherapy with cisplatin, ifosfamide and doxorubicin followed by the same therapy in March 1996, without serious side effects. MFH is known to be resistant to ordinary chemotherapy. However, the CT showed a marked decrease in the size of the tumor, and the tumor disappeared within 2 months after the first treatment. The patient also recovered rapidly from abdominal pain, for which complete remission has been achieved for more than 5 years. The present chemotherapy may be an effective treatment for retroperitoneal MFH.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Aortic valve repair of congenital bicuspid aortic valve associated with aneurysm of the ascending aorta.

Two unusual cases of congenital bicuspid aortic valve associated with aneurysm of the ascending aorta are reported. One patient with a 7-cm ascending aortic dilatation and aortic regurgitation (AR) (II/IV), and another with a 6-cm ascending aorta and AR (III/IV), presented for treatment. Replacement of the ascending aorta and aortic valve repair were performed in both cases. Aortic valve repair included resection of the raphe, leaflet plication and subcommissural annuloplasty. Both patients had satisfactory results in the early postoperative period. Despite the promising outcomes after surgery in these patients, long-term changes in valve function and durability remain unknown. Additional close observation and monitoring are required before the procedure can be recommended as the standard of care.

Aged↗
PubMed2001

[A case of Coxiella burnetii pneumonia in an adult].

A 49-year-old man visited our hospital complaining of a continuous high-grade fever and cough which had appeared during his stay in Indonesia. He was admitted on the same day because his laboratory data showed marked inflammatory changes and his chest radiograph revealed an infiltrative shadow in the right upper lung field. Initial treatment with beta-lactams was not effective and both his symptoms and his chest radiograph worsened. However, treatment with erythromycin clearly had an effect. Then, we carried out several tests for detection of atypical pathogens including Mycoplasma and Chlamydia. Finally, the case was diagnosed as one of Coxiella burnetii pneumonia because the DNA of C. burnetii was detected from his sera and seroconversion of C. burnetii--specific antibody was observed among paired serum samples. C. burnetii is one of the most commonly recognized pathogens among community-acquired pneumonias in Western countries, but in Japan, reports of community-acquired C. burnetii pneumonia have been rare. This difference may be due to the features of Q fever, in which there are large differences in frequency and form from country to country and among areas of the same country. Surveillance of C. burnetii pneumonia in Japan and different area will be required.

Anti-Bacterial Agents↗
PubMed2001

Cytological examination of rat amniotic epithelial cells and cell transplantation to the liver.

It is hoped that amniotic epithelial cells can be useful in cell-mediated gene therapy. We report here an experimental cell transplantation model of amniotic cells in rats. There is an anatomical difference between human and rodent embryos. We established a method to isolate amniotic cells that are equivalent to human amniotic epithelial cells. An amniotic membrane distinct from the yolk sac was carefully collected and teased in saline containing deoxyribonuclease and hyaluronidase, followed by collagenase digestion. The cell yield was approximately 10(6) cells per pregnant female (10(5) cells per fetus), roughly in proportion to the age of fetus used, and 60% of the isolated cells were attached to the dish under culture conditions. Telomerase activity was higher in the cells isolated from fetuses in the middle stage (day 13.5 to 15.5) than in the late stage (day 17.5 to 21.5). Adherent cells exhibited two to three times more cell division, resulting in a ninefold increase in the number of cells. Immunohistochemical analysis revealed that approximately half of the adherent cells were albumin positive and formed clusters. The senescent cells survived for 2 months without apparent morphological changes. The adherent cells were able to be stored in liquid nitrogen and had a viability of 70% when thawed. Gene transduction with adenovirus vector was highly effective for rat amniotic cells. Transplantation of lacZ transfected amniotic cells into syngeneic rat liver resulted in the integration of the transplanted cells in the liver structure and the cells survived for at least 30 days.

Albumins↗
PubMed2001

[Usefulness of combination post-stress dysfunction and perfusion imaging in technetium-99m-tetrofosmin myocardial scintigraphy].

OBJECTIVES: Myocardial perfusion imaging has lower sensitivity for the diagnosis of coronary artery disease in patients with three-vessel disease. The presence of post-stress dysfunction of the left ventricle, evaluated by electrocardiography(ECG) gated single photon emission computed tomography(SPECT) with a quantitative gated SPECT program, was investigated in patients with coronary artery disease, and also whether combining post-stress dysfunction and myocardial perfusion imaging improved the diagnosis of coronary artery disease. METHODS: ECG gated technetium-99m-tetrofosmin SPECT was performed using a one day, stress and rest, protocol in 139 patients. SPECT and coronary angiography were performed within 1 month. The coronary artery disease group consisted of 89 patients: 43 with one-vessel disease(1VD), 28 with two-vessel disease(2VD), and 18 with three-vessel disease(3VD). The group with zero-vessel disease(0VD) consisted of 50 patients. According to post-stress and rest ejection fraction(EF) and end-systolic volume (ESV), post-stress dysfunction is defined as follows: rest EF--post-stress EF > or = 5% and post-stress ESV--rest ESV > or = 5 ml. RESULTS: In the coronary artery disease group, post-stress ESV was larger than rest ESV(37.8 +/- 26.4, 34.0 +/- 24.2 ml, p < 0.001), and post-stress EF was lower than rest EF (61.5 +/- 11.1%, 64.2 +/- 10.8%, p < 0.001). In the 0VD group, ESV and EF were the same for post-stress and rest (25.7 +/- 20.8, 26.2 +/- 21.6 ml, NS; 70.4 +/- 9.5%, 70.0 +/- 9.6%, NS). Post-stress dysfunction was 6.0% in the 0VD group and 30.3% in the coronary artery disease group(p < 0.001). Furthermore, post-stress dysfunction in the 2VD (35.7%) and 3VD(38.9%) groups was higher than that in the 0VD group(p < 0.01, p < 0.01). Sensitivity of coronary artery disease diagnosis by myocardial perfusion imaging was 75%. The combination of post-stress dysfunction and myocardial perfusion imaging improved sensitivity from 75% to 82%(p < 0.05), but reduced the specificity from 92% to 86%(p = 0.08). CONCLUSIONS: Post-stress dysfunction is a useful parameter for clinical diagnosis of coronary artery disease.

Aged↗
PubMed2001

[Clinical effectiveness of intra-arterial chemotherapy combined with degradable starch microspheres (DSM) for liver metastases and prediction of effectiveness by diagnostic imaging].

The aim of this study was to evaluate the clinical effectiveness of intra-arterial chemotherapy combined with degradable starch microspheres (DSM) for liver metastases and the possibility of predicting the effectiveness of the chemotherapy by pretreatment diagnostic imaging. The subjects were 67 patients with metastatic liver cancer, treated with Seldinger method via the left brachial artery, and tumor selective hepatic injection using a micro-catheter. The early response rate was 38.7% for colorectal cancer, 42.8% for gastric cancer, 16.7% for bile tract cancer and 80% for uterine cancer. The relationship between effectiveness and the tumor occupation rate in the liver estimated from pretreatment CT images was not significant, but the degree of tumor stain in the early phase of contrast enhancement CT correlated well with early responsiveness of the liver metastases for this treatment. This suggests the possibility of pretreatment prediction of the effectiveness of intra-arterial chemotherapy combined with DSM for metastatic liver tumors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

[Analysis of regional cerebral blood flow and distribution volume in Machado-Joseph disease by iodine-123I IMP single photon emission computed tomography].

Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Its clinical features vary greatly in different generations of the same family. Regional cerebral blood flow (rCBF) and distribution volume (Vd) in the pons, cerebellum, and cerebral cortex were measured in 12 patients with MJD by autoradiography (ARG) and the table look-up (TLU) method of iodine-123 IMP (123I-IMP) single photon emission computed tomography (SPECT). Representative cases were as follows: A 46-year-old woman first experienced gait ataxia at age 38. Computed tomography (CT) and magnetic resonance imaging (MRI) showed no atrophy in the pons or cerebellum, but rCBF measured by the 123I-IMP SPECT ARG method detected hypoperfusion in the pons, and cerebellar vermis and hemisphere. A 76-year-old woman first experienced gait ataxia at age 69. CT and MRI findings showed severe atrophy in the pons, and cerebellar vermis and hemisphere. Moreover, rCBF was decreased in the pons, whereas it was not decreased in the cerebellar vermis and hemisphere. In the pons of patients with MJD, rCBF was markedly decreased regardless of disease severity. Because this SPECT finding for the pons looked like a 'dot', we have called it the 'pontine dot sign'. In the MJD group, rCBF was significantly decreased in the pons (Student's t test, p < 0.01) and cerebellar vermis (p < 0.05). The Vd was also significantly decreased in the pons (p < 0.005) in comparison with that for normal subjects. Pearson's correlation analysis yielded a significant relationship between the rCBF in the pons and age at onset (r = 0.578, p < 0.05). There was a strong correlation between the Vd for the pons and age at onset (r = 0.59, p < 0.05). Pearson's correlation analysis also showed a significant relationship between the Vd in the cerebellar hemispheres and International Cooperative Ataxia Rating Scale (r = 0.644, p < 0.05). The pontine rCBFs in patients with early onset MJD, whose pons was not atrophic, decreased more than did those in patients with late onset MJD, whose pons was severely atrophic. This suggests that the SPECT findings are indicative of underlying neurodegenerative processes that began before the onset of clinical symptoms. Different processes seem to function in atrophy and the rCBF decrease in the pons of patients with MJD. These findings will be proved by the increase of the number of cases of MJD. Until now, there has been no report on rCBF and Vd obtained by 123I-IMP SPECT for patients with MJD identified by gene analysis. Our study shows that SPECT measurement of rCBF and Vd is useful for understanding the pathophysiology of MJD.

Aged↗
PubMed2001

Studies on the effects of microgravity on the ultrastructure and function of cultured mammalian cells.

Four cultures of monkey kidney cell line, JTC-12, were flown on the Spacelab-J (SL-J) mission during 8 days. The results of the present study showed that the space flight gave no essential effect on morphology, cell cycle, glucose consumption and urokinase production of the mammalian culture cell. However, the cell proliferation slightly decreased under microgravity. Moreover, the lack of gravity induced the trypsin-treated dissociated cells to keep floating in the culture medium. Therefore, the attachment of the cells onto the substratum was delayed, and that caused difficulties in subculturing the cells. The present research also offered some important information on techniques for establishment of cell cultures in space laboratories.

Animals↗
PubMed2001

P53 and MDM2 co-expression in tobacco and betel chewing-associated oral squamous cell carcinomas.

Oral cancers of tobacco and betel chewers represents a unique in-vivo model to understand the genotoxic effect of tobacco and betel carcinogens on oncogenes and tumor suppressor genes. Coordinated interactions of p53 and MDM2 play an important role in regulation of critical growth control gene following exposure to DNA damaging agents. The purpose of this study is to determine if the tumor suppressor function of p53 is inactivated by mutation or other alternative mechanisms in carcinogen-induced oral squamous cell carcinoma (SCC), and to investigate the clinicopathological significance of p53 and MDM2 expression. The p53 mutation in oral SCC of tobacco and betel chewers (n=40) was detected by polymerase chain reaction - single strand conformation polymorphism (PCR-SSCP) analysis and immunohistochemistry (IHC) was done to investigate p53 and MDM2 proteins overexpression. The incidence of p53 mutation was relatively low (17.5%), but there was a high prevalence of MDM2 overexpression (72.5%). In the total of 40 cases, IHC phenotype showed p53 positive immunostaining with MDM2 positive immunostaining (p53+/MDM2+) 62.5%, p53 negative immunostaining with MDM2 negative immunostaining (p53-/MDM2-) 15%, p53 positive immunostaining with MDM2 negative immunostaining (p53+/MDM2-) 12.5%, and p53 negative immunostaining with MDM2 positive immunostaining (p53-/MDM2+) 10%. A significant correlation was found between MDM2 and p53 overexpression (p=0.0289). Moreover, p53+/MDM2+ phenotype was significantly associated with poorly differentiated tumors (p= 0.0007). These results conclude that other factors than p53 mutation is likely to be the targets of tobacco/betel carcinogens and MDM2 may play an important role in tobacco/betel chewing-related oral SCCs. Overexpression of MDM2 protein may constitute an alternative mechanism for p53 inactivation.

Areca↗
PubMed2001

[Microcirculation in the periodontal tissues].

There is the microcirculation in the periodontal tissues with one characteristic vessel network with the periodontal membrane and the gingival. Two levels blood vessels network in the periodontal membrane surrounds the tooth root. The inner and outer marginal epithelium has two levels blood vessels network in the gingival, and the blood vessels network under the epithelium sends in a loop of capillary toward the epithelium. The blood vessels network of the periodontal tissues is subjugated to a injury of extraction of a tooth, orthodontic tooth movement and implant. And almost overcome it after the 30th day when received on injury.

English Abstract↗
PubMed2000

A Role of RNA Helicase A in cis-Acting Transactivation Response Element-mediated Transcriptional Regulation of Human Immunodeficiency Virus Type 1.

RNA helicase A (RHA) has two double-stranded (ds) RNA-binding domains (dsRBD1 and dsRBD2). These domains are conserved with the cis-acting transactivation response element (TAR)-binding protein (TRBP) and dsRNA-activated protein kinase (PKR). TRBP and PKR are involved in the regulation of HIV-1 gene expression through their binding to TAR RNA. This study shows that RHA also plays an important role in TAR-mediated HIV-1 gene expression. Wild-type RHA preferably bound to TAR RNA in vitro and in vivo. Overexpression of wild type RHA strongly enhanced viral mRNA synthesis and virion production as well as HIV-1 long terminal repeat-directed reporter (luciferase) gene expression. Substitution of lysine for glutamate at residue 236 in dsRBD2 (RHA(K236E)) reduced its affinity for TAR RNA and impaired HIV-1 transcriptional activity. These results indicate that TAR RNA is a preferred target of RHA dsRBDs and that RHA enhances HIV-1 transcription in vivo in part through the TAR-binding of RHA.

Amino Acid Sequence↗