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Biomedical subjects

I Nakajima

Publications and source records attributed to I Nakajima.

At least 19 recordsLinked to original sources
PubMed2002

Relationship between functional disc position and mandibular displacement in adolescent females: posteroanterior cephalograms and magnetic resonance imaging retrospective study.

The purpose of this study was to investigate the relationship between the disc positions of temporomandibular joints (TMJ), the vertical and lateral mandibular displacement (VMD and LMD, respectively) and age in female adolescents with signs and symptoms of the temporomandibular disorders (TMD). The VMD and LMD were assessed, using posteroanterior (PA) cephalograms. The disc positions were assessed by magnetic resonance imaging (MRI) and categorized as follows: normal disc position, functional disc displacement and functional disc dislocation. Excluding patients with osteoarthritis, the total number of subjects was 54 female adolescents who were grouped into three: the bilateral normal disc position group, the unilateral or bilateral functional disc displacement group, and the unilateral or bilateral functional disc dislocation group. We compared the extent of VMD and LMD between the three groups, and investigated their correlation with age. Results indicate that functional disc displacement and dislocation are related to mandibular displacement, and VMD did not correlate with age but LMD did correlate with age. This study suggests that the onset of disc displacement is related to the mandibular displacement and disturbs normal growth of the mandible three-dimensionally.

Adolescent↗
PubMed2001

Alteration of collagen IV in acutely deteriorated renal allografts.

BACKGROUND: The changes in the basement membrane occurring in acutely deteriorated renal allografts (ADR) have not been extensively investigated. Our purpose is to elucidate the alteration of collagen IV, a main constituent of the basement membrane in ADR. METHODS: Fifty biopsy specimens of ADR and 10 of chronic transplant nephropathy (CTN) were examined with two monoclonal antibodies specific for collagen IV. JK199 and JK132 are monoclonal antibodies that recognize triple helical collagen IV containing the alpha1 chain. JK199 recognizes all the basement membrane containing [alpha1 (IV)]2alpha2(IV), although JK132 reacts only with a limited portion of it. In the normal kidney, JK199 reacts with the mesangial matrix, the basement membrane of Bowman's capsule (BBM), and the tubular basement membrane, as well as with the glomelular basement membrane (GBM). JK132 reacts with the mesangial matrix, BBM, and the tubular basement membrane. RESULTS: In ADR, increased intensity of JK199 was observed in GBM, the mesangial matrix, BBM, the tubular basement membrane, and the interstitium. Increased intensity of JK132 was observed in the mesangial matrix, BBM, and the tubular basement membrane, but was not remarkable in GBM or the interstitium. In contrast, biopsy specimens of CTN showed increased intensity of JK132 in GBM, the mesangial matrix, BBM, the tubular basement membrane and the interstitium. CONCLUSION: These results suggest that collagen IV is up-regulated in ADR. Differential staining of collagen IV with JK199 and JK132 in GBM and the interstitium may contribute to diagnose CTN.

Adult↗
PubMed2001

The final report of the project 'AMINE' the Asia Pacific Medical Information Network using with ETS-V.

Volunteer groups led by the Tokai University School of Medicine and the Telemedicine Society of Japan (a Non-Governmental Organization) worked from 1992 to 1996 to successfully develop a medical network spanning the Asia Pacific region using the ETS-V Satellite. The effort was part of the Partners project, sponsored by the Ministry of Posts and Telecommunications (MPT) and the National Space Development Agency of Japan. From 25 ground stations, links to the telemedical network were installed at medical institutions at no cost. The stations included five in Papua New Guinea, five in Thailand, four in Cambodia, four in Fiji, one in China, and six in Japan. Designed exclusively for medical applications, the network was operated free of charge for users at these sites. While the 16-kHz FM-based (Frequency Modulation-based) network limited applications to the transmission of color still images and audio and packet networking, the project still achieved impressive results. The network allowed liberal and independent use of international communications, local communications, teleconferences, and teleconsultations, without requiring a hub station.

Asia↗
PubMed2001

Video endoscopic database on WWW linking with ISDN.

We report here on a study of creating medical an image library comprised of simple but digitized gastrointestinal video-scope images, which were digitally compressed using MPEG-1 compression, and on the use of this library for clinical and educational applications. We have designed and installed a test-bed database (WWW) for gastrointestinal video-scope images linking with ISDN at 128 Kbps enables Internet access. This paper discusses its development, operation, problems, and educational and clinical use. A test-bed operation of the database was conducted by going on-line on the Internet and through an ISDN circuit (point-to-point connection) at a speed of 128 Kbps. This dynamic image database proved to be effective in diagnostic imaging for endoscopic diagnosis and treatment. It also proved to be useful for improving the clinical levels of geographically isolated physicians.

Computer Graphics↗
PubMed2001

Design of an SHD-distributed database over IP to support telemedicine.

We have conducted tests utilizing superhigh-definition CRTs (hereafter, referred to as a "super high-definition image system," or "SHD ": 2,048 x 2,048 pixels, 24-bit RGB gradation, noninterlace system) for autonomous and distributed medical image database systems. The system is capable of providing six times the image definition of a hi-vision television (HDTV). The aim in designing and testing the system is to enable gigabit network connectivity while displaying images on a DOS- V machine. This paper discusses how we devised an integrated environment for managing and operating distributed an SHD image database to support Telemedicine linking with ATM, with INS-1500, and with dial-up IP connection.

Computer Communication Networks↗
PubMed2001

Hemodialysis paradox: survey on the incidence rate of hepatocellular carcinoma in antihepatitis virus C-antibody-positive chronic hemodialysis patients.

The prevalence of antihepatitis virus C (HCV) antibodies in chronic hemodialysis (HD) patients is higher than in normal populations, and yet hepatocellular carcinoma (HCC) is infrequent in chronic HD patients who are HCV antibody positive. In this study, we investigated the characteristics of HCV-antibody-positive patients with HCC on chronic HD. A total of 6,366 cases of HCV-antibody-positive patients on chronic HD therapy was analyzed on the basis of answers to questionnaires on the incidence rate of HCC in 314 Japanese dialysis institutions. HCC was a complication in 114 of 6,222 (1.8%) HCV-antibody-positive patients, and cirrhosis was a complication in 536 of 6,242 (8.6%). The incidence rate of both complications was significantly higher in males than in females, and the incidence rate in the chronic HD patients was much lower than in normal populations. Specific immunological status in patients on chronic HD therapy may be an important key for preventing the progression of chronic HCV hepatitis. However, further research is needed because this study was preliminary and excluded the type of HCV virus, pathological findings, and laboratory data.

Carcinoma, Hepatocellular↗
PubMed2001

Age-related changes in cortical and trabecular bone mineral status. A quantitative CT study in lumbar vertebrae.

PURPOSE: To investigate the age and sex dependence of the bone mineral status of human lumbar vertebrae with special regard to differences between cortical and trabecular bone. MATERIAL AND METHODS: The study group comprised 125 normal Japanese healthy volunteers (54 males and 71 females), and was subdivided into adult male and female groups (subjects younger than 40 years), intermediate male and female groups (ages ranging between 41 and 64 years) and old male and female groups (subjects older than 65 years). The cortical bone mineral status was estimated using a single-energy quantitative CT (SE-QCT) technique, whereas trabecular bone mineral density (BMD) was estimated using a dual-energy (DE-QCT) technique. RESULTS: A considerable gender difference in the age-related cortical bone status was found. There was a significant reduction of the mean values of the cortical volume and BMD in the old female group compared with those obtained in the old male group. CONCLUSION: The results suggest that in men, cortical and trabecular bone volume decrease very little with age. In women, cortical volume and BMD and trabecular BMD decrease with age while trabecular bone volume does not. The study showed that all variables had higher values in men than in women and that the difference increased with age.

Adult↗
PubMed2001

Investigation and analysis of a reported incident resulting in an actual airline hijacking due to a fanatical and engrossed VR state.

We begin this report by defining Chronic Alternate-World Disorder (CAWD) as a symptomatic behavior in which a person becomes fanatically engrossed in a virtual-reality (VR) world to the extent that he or she can no longer distinguish between the actual world and virtual reality. We then report on our investigation and provide an analysis and discussion of what we believe to be a case of CAWD. The case in question involves a perpetrator who hijacked a jumbo jetliner in order to fly the airplane on his own, after developing CAWD from the use of light-simulator software. Psychiatrists and physicians specializing in VR-related disorders have analyzed the case's psychological, social, and technical background based on previously disclosed information. We believe symptomatic cases of CAWD will increase as VR spreads throughout our society. In view of this, our objective is to propose precautionary and preventive measures for providers of VR systems for patients with schizophrenia or personality disorders, from psychiatric and sociological perspectives.

Adult↗
PubMed2001

An experimental sclerosing encapsulating peritonitis model in mice.

BACKGROUND: Sclerosing encapsulating peritonitis (SEP) is a life-threatening complication of continuous ambulatory peritoneal dialysis. To elucidate the mechanism and develop treatments for this condition, an experimental SEP model in mice was constructed. METHODS: C57BL/6 mice were administered 0.3 ml of 0.1% chlorhexidine gluconate and 15% ethanol dissolved in saline, intraperitoneally, on a daily basis for 56 days (group 1, n=15). A control group of C57BL/6 mice were administered 0.3 ml of phosphate-buffered saline only in the same manner (group 2, n=15). The mice were sacrificed on days 3, 7, 21, 56 and were prepared for histological analysis. RESULTS: In group 1, all mice had developed macroscopic evidence of SEP 56 days after the injection. Microscopically we observed peritoneal fibrosis and an increase in infiltrates of mononuclear cells over time. The peritoneal fibrosis reached the chronic inflammatory stage by 56 days after the injection. CONCLUSION: We have developed a convenient experimental model of SEP in mice, which may be useful in elucidating the pathogenesis of SEP and in establishing possible treatments.

Animals↗
PubMed2001

Survey and analysis of satellite-based telemedicine projects involving Japan and developing nations: investigation of transmission rates, channel numbers, and node numbers.

We surveyed interactive telemedicine projects via telecommunications satellite (AMINE-PARTNERS, Post-PARTNERS, and Shinshu University Project using Inmarsat satellites) offered by Japan as assistance to developing countries. The survey helped clarify channel occupation time and data transfer rates. Using our survey results, we proposed an optimized satellite model with VSATs simulating the number of required channels and bandwidth magnitude. For future implementation of VSATs for medical use in developing nations, design of telecommunication channels should take into consideration TCP/IP-based operations. We calculated that one hub station with 30-76 VSATs in developing nation can be operated on bandwidth 6 Mbps using with 128 Kbps videoconferencing system for teleconsultation and teleconference, and linking with Internet.

Asia↗
PubMed2000

Anti-AB titer changes in patients with ABO incompatibility after living related kidney transplantations: survey of 101 cases to determine whether splenectomies are necessary for successful transplantation.

BACKGROUND: A shortage of organ donors for transplantation has become a serious problem throughout the world. To overcome this problem, transplantations across ABO blood barriers have been performed with some success. In general, however, the graft survival rate for transplantation with ABO incompatibility is lower than that of transplantation with ABO compatibility. Unfortunately, the mechanism by which isohemagglutinins might injure an ABO-incompatible graft remains uncertain. Here, the pre- and posttransplantation anti-AB titers in patients who received transplants from ABO-incompatible living donors are reviewed and the pathological findings are compared. METHODS: One hundred and one patients underwent ABO-incompatible living related kidney transplantation (i-LKT) between January 1989 and October 1999 at our hospital. Plasmapheresis and immunoadsorption were performed in all of the i-LKT patients before the transplantation to remove anti-AB antibodies. A splenectomy was also performed during the operation, followed by the local irradiation of the graft with a dose of 150 rad. The anti-AB titers and pathological findings for 93 i-LKT patients, excluding 8 patients who died, were then examined. RESULTS: Immediately after the i-LKT, the anti-AB titer dropped rapidly to below 1:4 in all 93 cases. Seventy of patients (70/93, 75%) showed no elevation in their anti-AB titer during their follow-up. However, the remaining 23 patients (23/93, 25%) showed a significant elevation of their anti-AB titer to over 1:16. Sixteen of these patients (16/93, 17%) exhibited an anti-AB titer of over 1:32. Out of these 16 patients, 11 patients (11/16, 69%) lost their grafts. The anti-AB titer in the remaining five patients (5/16, 31%) spontaneously decreased without any special treatment. Seven patients (7/93, 8%) exhibited an elevated titer of 1:16. Out of these patients, only one patient (1/7, 14%) lost his graft. The elevated titers in the remaining six patients (6/7, 86%) eventually decreased. The graft function improved in patients whose elevated anti-AB titers eventually decreased. Control patients (ABO-compatible kidney transplant patients) showed a normal elevation of their titer values compared with preoperative titers. Pathological findings showed severe humoral rejections in all cases with high anti-AB titers that lost grafts. Humoral rejection was also detected in most of the patients whose anti-AB titer was elevated to over 1:16 after the transplantation, but excellent renal function was resumed once the titers decreased to below 1:4. CONCLUSIONS: In 23 out of 93 i-LKT patients (25%), the anti-AB titers were significantly elevated after the splenectomy. In view of other reports of i-LKT without splenectomy, we feel that a splenectomy in i-LKT patients might be unnecessary. Pathological evidence suggests that the decrease in the anti-AB titer after transplantation might be the net result of plasmapheresis before the operation and the adsorption of antibodies to the endothelium of the transplanted organ after the operation, neither of which is influenced by a splenectomy.

ABO Blood-Group System↗
PubMed2000

Sialyl Lewis(x) (CD15s) monitoring as a means to select antirejection therapy in patients with rejection after renal transplantation: CD15s monitoring for treatment and diagnosis in patients with acute rejection after renal transplantation.

BACKGROUND: Sialyl Lewis(x) (CD15s), which is known to serve as a ligand for the cell adhesion molecules E-selectin and P-selectin, is expressed on peripheral lymphocytes in renal transplant patients with rejection. In this study, we examined whether CD15s monitoring could differentiate the patients with rejection in whom steroids were effective from those in whom steroids were not effective. METHODS: To investigate CD15s expression on peripheral lymphocytes, flow cytometry was performed before and after steroid pulse therapy in 20 recipients with rejection after renal transplantation, including 5 recipients resistant to steroid therapy. We also compared CD15s expression with pathological findings before and after steroid pulse therapy. RESULTS: CD15s expression was stronger before steroid pulse therapy in the 5 patients resistant to steroids than in the 15 patients responsive to steroid treatment. In addition, CD15s expression remained high without any pathological improvement in the 5 patients resistant to steroids after steroid treatment, although CD15s recovered to normal levels with remarkable improvement of pathological findings in the other 15 patients. Five patients in whom steroids were not effective, had full recovery of serum creatinine levels as well as CD15s expression after muromonab (OKT3) therapy. CONCLUSIONS: CD15s monitoring might help clinicians to select antirejection therapy.

Adult↗
PubMed2000

Clinical utility of monitoring sialyl Lewis(X) (CD15S) antigen on peripheral lymphocytes for the diagnosis and treatment of rejection after renal transplantation.

BACKGROUND: In organ transplantation, the grafts must be carefully monitored, but it is often difficult to make a quick and accurate diagnosis of unusual changes. Extensive research has failed to identify a useful marker for rejection. We investigated the clinical utility of sialyl Lewis(X) (CD15s) monitoring in 17 renal transplant patients with acute rejection. METHODS: The expression of CD15s on peripheral lymphocytes was examined using flow cytometry in renal transplant recipients with rejection (n=17), without rejection (n=23), recipients infected with cytomegalovirus (n=7), recipients with other diseases (n=7), and healthy volunteers (n=18). CD15s expression was compared with histological findings, and was also examined before and after steroid pulse therapy to investigate the effects of steroids on CD15s antigen expression on the surface of the peripheral lymphocytes. RESULTS: CD15s was strongly expressed in all patients with rejection, but was not expressed in any of the patients without rejection or in any healthy volunteers. Histologically, cell infiltration into the rejected graft was moderate or severe in all patients with strong expression of CD15s. In contrast, no or only mild infiltration was observed in patients with weak expression of CD15s. In addition, 14 of 17 patients (14/17, 82%) with strong CD15s expression improved upon administration of steroid pulse therapy, although there was no benefit from steroids in any of the patients with weak expression of CD15s. CONCLUSIONS: The CD15s antigen is expressed strongly on the peripheral lymphocytes at the time of rejection. It is interesting that the efficacy of steroid therapy in the patients with elevated creatinine could be predicted by CD15s expression on the peripheral lymphocytes before graft biopsy. There have been only few reports showing the relationship between CD markers and the efficacy of the treatment in patients with elevated creatinine. We report that the detection of CD15s on the peripheral lymphocytes by flow cytometry was an easy, helpful, and noninvasive means for the diagnosis and treatment of patients with elevated creatinine after renal transplantation.

Adult↗
PubMed2000

Factors affecting survival after living-related liver transplantation.

The purpose of this study was to determine the perioperative factors that influence patient and graft outcome in living-related liver transplantation (LRLT). Between April 1995 and October 1998, we performed a series of 46 LRLT procedures, including 11 adult cased, at our institute. Mean age and weight of the recipients were 12.0 +/- 2.3 years and 23.7 +/- 2.6 kg, respectively. Seven out of the 46 patients had renal failure and received hemodialysis therapy before and after LRLT or kidney transplantation. The recipients were divided into two groups: those who survived for 7-48 months after LRLT (group 1, n = 36), and those who died within 4 months after surgery (group 2, n = 10). Factors analyzed included recipient age and weight, graft/recipient body weight ratio (G/R ratio), emergent vs elective surgery, United Network for Organ Sharing (UNOS) status, presence of preoperative plasmapheresis (PEX) and renal failure, and so on. Recipients in group 1 compared with group 2 had less advanced liver disease (i. e., a lower rate of emergent surgery, 14% vs 50%, and fewer patients with UNOS status 1, 14% versus 70%; P < 0.05 and P < 0.001, respectively). Group 1 recipients also had a lower percentage of preoperative treatment with plasmapheresis (22% vs 70%, P < 0.01). However, neither the G/R ratio nor the presence of renal failure affected the patient survival rate. In conclusion, factors independently associated with reduced patient survival after LRLT include emergent surgery, Child-Pugh class, UNOS status 1, and preoperative plasmapheresis.

Adolescent↗