Search PubMed⌕ Search

Biomedical subjects

S Nakata

Publications and source records attributed to S Nakata.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Fontan procedure after pulmonary artery banding--surgical results and new anatomical repair for tricuspid atresia].

We examined our surgical experiences to determine the appropriate condition of pulmonary artery banding (PAB) for the Fontan procedure. From 1974 through 1992, thirteen patients underwent Fontan procedure following PAB at Tokyo Women's Medical College. Of these 6 had tricuspid atresia (TA), 5 had single ventricle, or 2 had other complex malformations. PAB was performed at the age of 1 to 14 months (mean 2.5 months). With monitoring pulmonary artery (PA) pressure and systemic arterial oxygen tension (PaO2), PA mean pressure decreased 43.6 to 18.8 mmHg and PA circumferences at the banding site decreased from 53.5 to 26.0 mm after PAB. This degree of PAB was tighter compared with the value estimated by Trusler's formula (27.9 mm) in most patients. After PAB, 5 patients required 8 additional palliative surgery including 3 systemic to pulmonary shunt, 3 rebanding, 1 palliative RVOTR to promote development of pulmonary vascular bed and 1 atrial septectomy to prevent pulmonary hypertension. Hemodynamic data before Fontan operation showed a tendency of higher PA pressure (17.5 vs 31.5 mmHg), and pulmonary vascular resistance (2.4 vs 5.5 Wood Unit) in non-survivors than in survivors. For patients with tricuspid atresia and high pulmonary vascular resistance, a new operation "Anatomical Repair" utilizing hypoplastic right ventricle with the translocation of pulmonary or aortic valve in tricuspid position was developed and successfully applied in three patients. In conclusion, initial tight PAB during early infancy and often repeated palliative surgery for development of adequate pulmonary vascular bed is the most important for maximizing the chance of subsequent successful Fontan procedure.

Age Factors↗
PubMed1995

[Epidemiological study of risk factors for bladder cancer].

A case-control study was conducted on 303 male bladder cancer patients and controls. General population controls were chosen from 15 areas in Gunma Prefecture and were matched by age (+/- l y.o.) to the subjects. Age-adjusted and smoking-adjusted odds ratio (O.R.) and a 95% confidence interval (C.I.) were calculated for each item. Risk factors for bladder cancer in men were investigated. The O.R. tended to be significantly higher for those who had history of smoking, who smoked more per day, who had smoked longer, whose Brinkman index was higher, who began smoking younger and who inhaled deeper than it was for non-smokers. O.R.s of having a past history or complication of cystitis (age-adjusted) and benign prostatic hypertrophy (age- and smoking-adjusted) were significantly higher, but the difference was supposed to be caused by bias. There was a significantly lower age- and smoking-adjusted O.R. for bladder cancer in men who engaged in sales, whose blood type was O, who drank milk frequently, who ate grains frequently, who age vegetables frequently and who had a past history or complication of hypertension. The number of cases and controls with first degree family members who developed cancer respectively supposed to be highly related to smoking, were as follows; 16 and 8 for lung cancer, 3 and 0 for larynx cancer and 6 and 3 for bladder cancer. The following characteristics failed to show any significant difference between subjects with bladder cancer and the control group; height and weight now and 20 years ago, jobs which deal with dye, academic career, marriage, number of children, alcohol drinking and the use of hair dye or analgesics.

Adult↗
PubMed1994

Hepatitis C virus variants from Vietnam are classifiable into the seventh, eighth, and ninth major genetic groups.

Thirty-four (41%) of 83 hepatitis C virus (HCV) isolates from commercial blood donors in Vietnam were not classifiable into genotype I/1a, II/1b, III/2a, IV/2b, or V/3a; for 15 of them, the sequence was determined for 1.6 kb in the 5'-terminal region and 1.1 kb in the 3'-terminal region. Comparison of the 15 Vietnamese isolates among themselves and with reported full or partial HCV genomic sequences indicated that they were classifiable into four major groups (groups 6-9) divided into six genotypes (6a, 7a, 7b, 8a, 8b, and 9a). Vietnamese HCV isolates of genotypes 7a, 7b, 8a, 8b, and 9a were significantly different from those classified into groups 4, 5, and 6 based on divergence within partial sequences; those of genotype 6a were homologous to a Hong Kong isolate (HK2) of genotype 6a. Phylogenetic trees based on the envelope 1 (E1) gene (576 bp) of 55 isolates and a part of the nonstructural 5 (NS5) region (1093 bp) of 43 isolates revealed at least nine major groups, three of which (groups 7, 8, and 9) were identified only in Vietnamese blood donors. With a prospect that many more HCV isolates with significant sequence divergence will be reported from all over the world, the domain of the HCV genome to be compared and criteria for grouping/typing and genotyping/subtyping will have to be determined, so that they may be correlated with virological, epidemiological, and clinical characteristics.

Base Sequence↗
PubMed1994

Effects of transfected complement regulatory proteins, MCP, DAF, and MCP/DAE hybrid, on complement-mediated swine endothelial cell lysis.

We established several swine endothelial cell (SEC) lines, expressing human MCP (CD46), DAF (CD55), and MCP/DAF hybrid by transfection of cDNA, and assessed the function of these transfectant molecules on complement-mediated cell lysis as an in vitro hyperacute rejection model of swine to human discordant xenograft. Discordant organ xenografts are hyperacutely rejected by complement activation. Amelioration of complement-mediated lysis by these transfectant molecules was tested in each SEC line by lactate dehydrogenase assay. Naive swine endothelial cells were markedly damaged by human complement mainly via the classical pathway, activating only minimally the alternative pathway of human complement. Both MCP and DAF protected SEC from human complement attack in parallel with the expression density, with DAF being more effective than MCP. The MCP/DAF hybrid was more effective than MCP alone, and as effective as DAF in this system. The results suggest that the transfection of DAF or the MCP/DAF hybrid cDNA into organs to be transplanted could protect against hyperacute rejection.

Animals↗
PubMed1994

Analysis of rejection mechanism in the rat to mouse cardiac xenotransplantation. Role and characteristics of anti-endothelial cell antibodies.

Recent reports have demonstrated that humoral factors, especially antibodies elicited by xenoantigens, play an important role in the rejection of concordant cardiac xenografts. These induced antibodies, however, have not been well characterized. Therefore, we investigated the rejection mechanism, especially the role of humoral immunological responses in the concordant rat to mouse cardiac xenograft model. Lewis rat hearts transplanted into C3H/HeN mice were rejected in 5-6 days. The essential role of humoral factors in the rejection was demonstrated by histological analysis of the rejected hearts showing interstitial hemorrhage, scant cellular infiltration, and the dense deposition of mouse IgG, IgM, and C3 on the graft endothelial cells. In addition, mice that received hyperimmune serum (serum at the 10th day after transplantation) rejected rat hearts hyperacutely. Flow cytometrical analysis using cultured donor rat coronary endothelial cells demonstrated the xenoreactive antibodies of all subclasses, but especially strong reactivity of IgM and IgG2a in the serum at rejection. These xenoreactive antibodies were produced against not only MHC, but also non-MHC antigens on graft endothelial cells. In vivo depletion of L3T4+ T cells led to the suppression of xenoreactive antibody production and the prolongation of graft survival, indicating that antibody production in this model needs L3T4+ T cell help.

Animals↗
PubMed1994

The rejection mechanism of rat pancreaticoduodenal allografts with a class I MHC disparity.

The present study has demonstrated for the first time that PVG.R1 (RT1.AaBcDcCc) pancreatic grafts are rejected by so-called "low"-responder PVG (RT1.AcBcDcCc) recipients with an isolated class I MHC disparity (mean survival time; MST: 21.4 +/- 1.8 days, n = 5), whereas PVG.R1 heart grafts are able to survive indefinitely (MST: > 100 days, n = 5). Splenic CD4+ T cells but not CD8+ T cells from the PVG recipients of PVG.R1 pancreatic grafts show a remarkable proliferative response against donor class I RT1.Aa alloantigens, while only a minimal proliferation is observed in the PVG recipients of PVG.R1 heart grafts or naive PVG rats. Naive PVG rats display an extremely low frequency of IL-2-producing helper T cell precursors (fThp) of 1/40,609 +/- 15,441 against class I RT1.Aa alloantigen. The PVG recipients of PVG.R1 heart grafts have a slightly greater fThp of 1/17,326 +/- 6822. On the other hand, the PVG recipients that rejected PVG.R1 pancreatic grafts show a significantly increased fThp of 1/5030 +/- 3396 compared with those of PVG.R1 heart grafts (P < 0.05) or naive PVG rats (P < 0.01). The frequency of cytotoxic T cell precursors (fTcp) increases slightly in the PVG recipients of PVG.R1 pancreatic grafts (1/1848 +/- 330) compared with those of PVG.R1 heart grafts (1/2215 +/- 2131) or naive PVG rats (1/2476 +/- 585). The size of cytotoxic T cell clones alone does not adequately account for a proliferation sufficient to complete the rejection of pancreatic grafts. The PVG recipients of PVG.R1 pancreatic grafts, but not heart grafts, demonstrate a strong cytotoxic alloantibody response to donor class I RT1.Aa alloantigens. In the study of alloantibodies, IgM is detected mainly in the early phase and IgG in the late phase during the course of pancreatic rejection. It is determined that in blocking studies by FACS analysis these antibodies target class I MHC antigens. These results suggest that cytotoxic T cells do not appear to be responsible for the rejection of PVG.R1 pancreatic grafts in PVG recipients. Rather, the rejection is mediated by CD4+ T cells and complement-fixing antibodies directed at class I MHC antigens.

Animals↗
PubMed1994

Nonsurgical correction for thrombosis of a St. Jude Medical tricuspid prosthesis: report of a case.

A 43-year-old woman with rheumatic heart disease underwent replacement of the aortic, mitral, and tricuspid valves using three SJM prostheses. Despite adequate warfarin therapy, routine cineradiography performed on the 40th postoperative day showed one of the leaflets of the tricuspid prosthesis to be "stuck" in the semiclosing position. A thrombosis of the tricuspid prosthesis was successfully treated with a urokinase infusion and mechanical thrombolysis using a pacemaker, following which normal valve function was restored.

Adult↗
PubMed1994

Study of efficacies of leukocyte-depleted terminal blood cardioplegia in 24-hour preserved hearts.

To evaluate the effect of leukocyte-depleted terminal blood cardioplegia on prolonged preservation, 41 canine hearts were stored in modified Collins' solution and transplanted heterotopically. Hearts were transplanted soon after harvesting in group 1 and after 24-hour preservation in groups 2, 3, and 4. Blood cardioplegia was applied just before aortic unclamping in groups 3 and 4; group 3 received simple blood cardioplegia and group 4 received leukocyte-depleted cardioplegia. The percentage of the preload recruitable stroke work and diastolic compliance after transplantation compared with the preharvesting value in group 4 did not differ from those in group 1, but the percentage of the preload recruitable stroke work in groups 2 and 3 was significantly lower than that in groups 1 and 4. The percentage of diastolic compliance in groups 2 and 3 was significantly higher than that in groups 1 and 4. Coronary blood flow 40 minutes after aortic unclamping in group 4 did not differ from that in group 1, but was significantly higher than the blood flows in groups 2 and 3. Significant production of malondialdehyde was detected during terminal blood cardioplegia and 10 minutes after aortic unclamping in groups 2 and 3, but never in groups 1 and 4. After leukocyte-depleted terminal cardioplegia, the myocardial adenosine triphosphate content increased to the preharvesting value in group 4. Our results suggest that leukocyte-depleted terminal blood cardioplegia may be effective in replenishing the energy-depleted myocardium and reducing reperfusion injury, resulting in adequate cardiac function.

Adenosine Triphosphate↗
PubMed1994

Efficacy of rhesus rotavirus vaccine MMU-18006 against gastroenteritis due to serotype 1 rotavirus.

We conducted a clinical trial of rhesus rotavirus vaccine MMU-18006 (RRV, serotype 3) to assess the immunogenicity, transmissibility and booster effect of this vaccine in a welfare nursery in Sapporo, from September 1986 to October 1988. After the trial, in March 1989, an outbreak of gastroenteritis due to a wild strain of serotype 1 rotavirus (RV-1) occurred in the study population. Infants were divided into three groups based on vaccination history: five booster vaccinees, 18 one-dose vaccinees and 18 control infants who did not receive vaccine. There was a significant relationship between asymptomatic infection and higher levels of preoutbreak antibody titres against KU (serotype 1) but not RRV. Significant protection from rotavirus illness was observed both in the booster vaccine group and in the one-dose vaccine group but not in the control group. Rotavirus-specific serum IgA immune response was considered to be one of the indicators of recent rotavirus infection, and did not correlate with resistance to rotavirus illness. Our results revealed that protection from rotavirus illness was serotype-specific and that previous rotavirus infection, including vaccination, was important to induce the heterotypic immune response, and that ageing or booster inoculation of RRV might play a role in the protection against serotype 1 rotavirus infection. From our findings, a booster administration was thought to be important to induce effective heterotypic immunity and should be included in a future rotavirus vaccine trial to obtain sufficient protection against four major serotypes of rotavirus.

Antibodies, Viral↗
PubMed1994

Detection of HTLV-II-seropositive blood donors in South Vietnam but not in North Vietnam.

Approximately 1% (4/500) of blood donors exhibited seropositivity for HTLV-II in South Vietnam, but none (0/500) did in North Vietnam. Further, all individuals seropositive for HTLV-II were intravenous drug abusers who were seronegative for HIV-1 and HTLV-I. These findings suggest that HTLV-II infection may be specifically prevalent in drug abusers in South Vietnam.

Blood Donors↗
PubMed1994

Role of CD4+ T cells in the rat to mouse cardiac xenotransplantation.

T cell subsets involved in rejection of xenografts were analyzed using a rat to mouse cardiac xenotransplant model. Proliferating response and interleulin-2 (IL-2) production in recipients' spleen cells were almost completely abrogated by elimination of L3T4+ T cells, but not by elimination of Lyt2.1+ T cells. Cytotoxic T lymphocyte (CTL) activities were mediated by both L3T4+ and Lyt2.1+ T cells with the help of IL-2-producing L3T4+ T cells. Administration of anti-L3T4 monoclonal antibody (mAb) into recipient mice resulted in a significant prolongation of graft survival (mean graft survival was 29.2 days). Moreover, anti-L3T4 mAb treatment plus thymectomy led to indefinite graft survival. Anti-rat endothelial cell (EC) antibody production in the grafted mice was remarkably suppressed by anti-L3T4 mAb treatment. In contrast, Lyt2.1 mAb treatment did not prolong the graft survival and did not suppress anti-EC antibody production. These results indicated the absolute requirement of L3T4+ T cells in the rejection of rat to mouse cardiac xenografts.

Animals↗
PubMed1994

Minocycline-induced hemolytic anemia.

A case of drug-induced immune hemolytic anemia is described. A 2 year old boy exhibited sudden anemia and hemoglobinuria after administration of minocycline (MINO). The specific immunoglobulin G antibody against MINO was demonstrated in the patient's serum by western blotting. This is a rare example where anti-minocycline immune complex-mediated hemolysis was responsible for an intravascular hemolytic process.

Anemia↗
PubMed1994

Epidemiology of urological cancer deaths in Japan.

We analyzed mortality data (1973-84) associated with 19 major cancers in Japan. The standardized mortality ratio (SMR) for prostate cancer was high in prefectures clustered in the Kanto-Chubu and Kyusyu regions, and that for renal cancer was high in prefectures scattered over eastern Japan. On the other hand, the SMR for prostate cancer was low in prefectures in the Kinki and Shikoku regions. In males, the SMR for bladder cancer was low in the Kanto and Chubu regions, and that for renal cancer was low in the Kanto-Chubu, Shikoku and Kyusyu regions. The correlation between the prefectural SMR for urological cancers and other cancers was analyzed. Pairs of cancers which were fairly highly correlated (0.5 or higher) were bladder-lung, kidney-colon, kidney-breast, kidney-ovary, and kidney-pancreas. For most cancers, the prefectural SMR in males was highly correlated (0.5 or higher) with that in females. However, for cancer of the bone, bladder, skin and larynx, the correlation coefficient was less than 0.5. In 14 of the 19 cancers examined, the slope of the logarithm of the age-specific mortality rate plotted against the logarithm of age was linear, and the relationship between age and mortality rate could be expressed by the formula Log M (mortality rate) varies; is directly proportional to nLog T (age) The value of "n" calculated using the formula ranged from 4 to 7 for most cancers, and was highest (9.5) for prostate cancer.

Adolescent↗
PubMed1994

A comparison of prostate cancer patients in Japan and the USA.

Clinical characteristics of prostate cancer patients were analyzed to compare the rates of progression of prostate cancer between patients in Japan (Gunma Urological Oncology Study Group: GUOSG) and the USA (Roswell Park Cancer Institute: RPCI), between 1980 and 1989. The stage of disease was more advanced and the age was greater in GUOSG patients compared with RPCI patients. However, the prostate cancer death rate of stage D patients at RPCI was significantly higher than that of the GUOSG. Moreover, the survival rate of stage A patients in the GUOSG was better than that of RPCI patients. The possibility of biases which may affect both the clinical characteristics and survival rates in the 2 populations studied is discussed. To determine whether there is a real difference in the rate of prostate cancer growth between the 2 countries will require a prospective study, ideally conducted in large population groups.

Age Distribution↗
PubMed1994

Markers of hepatitis C and B virus infections among blood donors in Ho Chi Minh City and Hanoi, Vietnam.

Blood donors in two cities in Vietnam were tested for markers of hepatitis C virus (HCV) and hepatitis B virus infections. Antibody to HCV was detected by passive hemagglutination with antigens of the second generation in 101 (20.6%) of 491 donors in Ho Chi Minh City; it was detected less frequently (P < 0.001) in donors in hanoi (4 [0.8%] of 499). HCV RNA was tested for in donors with antibody by PCR with nested primers from the 5'-noncoding region and detected in 79 donors in Ho Chi Minh City and 4 donors in Hanoi. HCV RNA was genotyped by PCR with type-specific primers from the core gene. Of 83 HCV carriers from Vietnam, 24 (29%) were infected with HCV of genotype I/1a 19 (23%) were infected with II/1b, 4 (5%) were infected with III/2a, and 2 (2%) were infected with mixed genotypes (I/1a and II/1b); HCV genotypes in the remaining 34 (41%) donors, including all 4 donors in Hanoi, were not classifiable into I/1a, II/2a, IV/2b, or V/3a. Of the 10 isolates with unclassifiable genotypes, 2 showed substantial sequence divergence within the 5'-noncoding region from reported isolates with known genotypes (I/1a to 6a). An analysis of part of the core gene sequence indicated that six of the remaining isolates most likely represented new HCV genotypes. Hepatitis B surface antigen and the corresponding antibody, respectively, were detected in 15 (3.1%) and 234 (47.7%) donors in Ho Chi Minh City as well as 15 (3.0%) and 248 (49.7%) donors in Hanoi. These results indicate an extensive spread of HCV among Ho Chi Minh City donors and HCV of novel genotypes in vietnam.

Adult↗