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Biomedical subjects

S Nakata

Publications and source records attributed to S Nakata.

At least 181 records · Page 10Linked to original sources
PubMed1994

Epidemiological study of Norwalk virus infections in Japan and Southeast Asia by enzyme-linked immunosorbent assays with Norwalk virus capsid protein produced by the baculovirus expression system.

In this study, we investigated Norwalk virus (NV) antigen and antibody to recombinant NV (rNV) in human populations in Japan and Southeast Asia by enzyme-linked immunosorbent assays (ELISAs). Baculovirus-expressed recombinant NV (rNV) capsid protein was used for preparing antisera to rNV or used as an antigen for detecting antibody to rNV. The ELISAs were specific for NV and had sensitivities equivalent to or higher than those of the previously developed radioimmunoassays. In 159 stool samples obtained from children, mainly younger than 10 years old, with acute gastroenteritis due to small round structured viruses in Japan, only 1 was positive for NV antigen. The pattern of acquisition of antibody to rNV was quite different from those of antibodies to group A rotavirus and human calicivirus Sapporo (HuCV-Sa) strain. The prevalence of antibody to rNV remained at a low level throughout childhood and then showed a steep rise during school age and early adulthood in Japan. A high prevalence of antibody was observed in samples collected from healthy adults in Japan and Southeast Asia. These results suggested that NV infection is common in adults in Japan and Southeast Asia but may be rare in infants in Japan. The HuCV-Sa strain was negative by the ELISA, and no serological relationship between NV and the HuCV-Sa strain was found. NV may be quite different from the HuCV-Sa strain, although both viruses are classified in the family Caliciviridae.

Adolescent↗
PubMed1994

Prognosis of patients with severe congestive heart failure referred to the cardiac transplant program. Osaka University Cardiac Transplant Program.

In any program for cardiac transplantation, appropriate recipient selection is critically important. The purpose of this study is to evaluate the prognosis of 42 patients with severe cardiac dysfunction who were referred to the Patient Referral Committee of the Osaka University Cardiac Transplant Program from August 1990 to July 1993. All of the patient profiles and clinical data were presented and discussed in the Committee Conference. The Committee classified the patients into three groups according to the following criteria: Class A; 14 patients judged to have a medical indication for heart transplantation, Class B; 7 patients with possible indications which required reevaluation for a definite indication after further intensive medical treatments, and Class C; 21 patients who did not have indications for heart transplantation or who required further clinical examinations and/or medical treatments before a final judgment. Twelve of the 14 Class A patients had a history of NYHA functional class IV and ejection fractions were 25% or less in all of the patients but one (18.5 +/- 1.7%). Six patients in Class A had a history of ventricular tachycardia. The one-year survival rate of Class A patients was 60%, and only 28% survived for 28 months. One patient underwent successful heart transplantation in the United States. If we assume that this patient would have died within a year without heart transplantation, the estimated one-year survival rate would fall to 48%, which is comparable to the survival rate of patients who have been accepted for transplant, but are being treated medically, in Western countries.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

[An epidemiological study of urogenital cancer in Gunma Prefecture].

The incidence and mortality rate of urogenital cancers in Japan are both low compared to those in western countries. However, the incidence and mortality patterns of cancer in Japan are currently becoming closer to those of western countries, and the importance of urogenital cancers is increasing. We conducted an analysis of urogenital cancers in Gunma Prefecture. The subjects were newly detected urogenital cancer patients living in Gunma Prefecture diagnosed between 1985 and 1992. Details were as follows: prostate cancer 1411, bladder cancer 1253 (male 937, female 316), renal cell carcinoma 411 (male 287, female 124), renal pelvic and ureter cancer 187 (male 127, female 60) and testicular cancer 162. Incidence rate was calculated by year, district and age, and was expressed per 100,000/year and was adjusted to world population. Regarding the incidence rate per year for males, that of prostate cancer and renal cell carcinoma increased dramatically from 8.3 to 13.6 and from 1.1 to 3.2, respectively. Incidence rate of other cancers in males showed a slight increase or remained almost stable. Incidence rate by year for females showed a slight increase or remained almost stable as a whole. Gunma Prefecture was divided into 10 districts by the range of daily life of people and the incidence rates of prostate cancer, bladder cancer and renal cell carcinoma for each district were calculated. Incidence rate of prostate cancer tended to be higher in the northern parts of the prefecture, while that of bladder cancer showed no detectable trend.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Aortic valve replacement in a kidney transplant recipient].

A 62-year-old man with chronic renal failure, who had been treated with hemodialysis, received a kidney transplant from his son in December 1989. He kept good renal function without any episode of graft rejection under the immunosuppressive therapy with Cyclosporine A (CyA), Predonine (PRD), and Mizoribine. In 1990 he started to have exertional dyspnea, and was diagnosed to have aortic valve regurgitation. He underwent aortic valve replacement in September, 1991. He was treated with continuous infusion of CyA and bolus injection of methylprednisolone from the start of the operation, and returned under the preoperative immunosuppressive therapy after oral intake became possible. On the third post-operative day, the level of serum creatinine elevated. Although we couldn't detect significant changes in subpopulations of peripheral blood lymphocytes, steroid pulse therapy was performed as the possibility of acute rejection was underiable. Serum creatinine returned to normal level in a few days and the postoperative course after that was uneventful. He was discharged on the 30th post-operative day.

Aortic Valve↗
PubMed1994

[Reoperation after surgical repair of atrioventricular canal defect].

Among 114 survivors who underwent total repair of atrioventricular canal defect between 1981 and 1993, 19 patients underwent reoperation for the occurrence and progression of mitral valve insufficiency (18 patients), thrombosed prosthetic valve (1 patient), and subaortic stenosis (4 patients) on one or two occasions after operation. There were 7 males and 12 females with ages at reoperation ranging from 3 months to 13.8 years (mean, 3.8 years), and was no operative but one late death. At reoperation, reparative procedures involving the readjustment of previously repaired mitral cleft and annuloplasty were successfully achieved in 6 patients who had no additional abnormalities of subvalvar apparatus. Twelve patients, who were associated with additional valvar and subvalvar lesions, needed a prosthetic valve replacement. We emphasized that surgical technique based on precise knowledge of each individual mitral and submitral anatomy is indispensable to achieve good surgical results. When the anatomy involves submitral abnormalities, careful postoperative follow-up should be recommended to take measures of the progression of mitral valve regurgitation.

Adolescent↗
PubMed1993

Epstein-Barr virus genomic sequences and specific antibodies in cerebrospinal fluid in children with neurologic complications of acute and reactivated EBV infections.

Four children with infectious mononucleosis (IM) and one with reactivated Epstein-Barr virus (EBV) infection had concomitant central nervous system disorders. Cerebrospinal fluid (CSF) samples from all five patients contained EBV genomic sequences and EBV-specific antibodies in the neurologic stage, but not during convalescence. Cerebrospinal fluid from two non-neurologic IM patients had neither EBV DNA nor EBV antibodies. The EBV-positive CSF of the five with neurological disorders were aseptic in culture and all negative for other human herpesvirus DNAs and antibodies: herpes simplex virus types 1 and 2, cytomegalovirus, varicella-zoster virus, and human herpesvirus 6. Epstein-Barr virus DNA and EBV antibodies were not detected in the CSF of 17 EBV-seropositive patients with mumps meningitis, rubella encephalitis, unknown febrile convulsion, or partial epilepsy. It is suggested that EBV plays a causal role in neurologic manifestations in patients with acute and reactivated EBV infections, through direct viral invasion and immunopathological reactions.

Acute Disease↗
PubMed1993

Significance of subclinical entrapment of nerves in lead neuropathy.

We examined a left-handed 25-year-old man engaged for 2 years at a vinyl chloride resin factory where he had been exposed to lead stearate, a stabilizer of resin. Neurological examination revealed atrophy of small hand muscles, especially in the left dorsal interossei. Sensation of all modalities was intact. A nerve conduction study showed conduction block at the elbow, indicating possible cubital tunnel syndrome. Following CaEDTA therapy, continued recovery of conduction velocities, amplitude of compound muscle action potential, and diminution of conduction block at elbow were observed within a few months. In lead intoxication, nerves may incur mechanical damage. Subclinical entrapment may thus be an important factor leading to vulnerability of nerves in lead neuropathy.

Action Potentials↗
PubMed1993

Virological and serological aspects of immune resistance to rotavirus gastroenteritis.

Some aspects of immune resistance to rotavirus gastroenteritis were assessed on the basis of clinical and laboratory findings during several outbreaks of gastroenteritis due to rotavirus of serotype 1 or 3 in a welfare nursery. Protection against rotavirus gastroenteritis was serotype specific and seemed to be related to levels of antibody to homotypic virus. The short duration of the protective effect may explain recurrent attacks of gastroenteritis due to the same serotype. Heterotypic antibody responses suggested that immunity to heterotypic virus can be induced by natural rotavirus infection or a rotavirus vaccine. Results of a field trial of a candidate vaccine, rhesus rotavirus strain MMU 18006, were used as a basis for evaluating strategies for vaccine development.

Antibodies, Viral↗
PubMed1993

Prolonging discordant xenograft survival with anticomplement reagents K76COOH and FUT175.

The guinea pig heart, when transplanted into the rat heterotopically, is rejected within 30 min via activation of the alternative complement pathway. Natural antibody does not contribute to rejection. This xenotransplantation model was used to assess the effect of anti-complement reagents on discordant xenograft survival. In vivo administration of K76COOH (K76) to rats induced only slight suppression of factors B and D and a marked decrease of C3, leading to the depression of ACH50 (reflecting the potency of the alternative pathway). On the other hand, FUT175 (FUT) reduced C3 activity by about 80% and inhibited factor B activity nearly 100% < 1 hr after the administration, but inhibited factor D activity only marginally. FUT abrogated ACH50 for > 6 hr. Of note, the xenograft beating time was prolonged approximately 3 times by FUT but not by K76, suggesting that direct inhibition of plasma serine protease factor B results in the complete suppression of ACH50 and graft survival. The administration of both K76 and FUT resulted in the longest graft survival, but the effects of these reagents were abolished by additional antigraft antibody. Anticomplement reagents that block factor B and C3 are therefore effective for prolongation of discordant xenograft survival when the graft rejection is associated with the complement alternative pathway.

Animals↗
PubMed1993

Test for ability of decay-accelerating factor (DAF, CD55) and CD59 to alleviate complement-mediated damage of xeno-erythrocytes.

We investigated the susceptibility to human complement (C) of xeno-erythrocytes into which phosphatidylinositol (PI)-anchored human C regulatory protein, decay-accelerating factor (DAF) or CD59 had been incorporated. Erythrocytes of sheep (Esh), swine (Esw), dog (Edg), and guinea pig (Egp), unsensitized with human natural antibody (Ab), were used as xeno-target. C-mediated lysis of erythrocytes (E) was induced in both classical and alternative pathways in parallel with the density of the sensitized Ab, except for Egp. The efficacy of DAF/CD59-mediated protection of the xeno E from human C, however, differed among these E species. In both classical and alternative pathways, Esh or Esw, which are non-activator surfaces, were protected by the incorporated DAF or CD59, DAF being more effective than CD59. On the other hand, CD59 was more effective than DAF in both pathways in protection of Egp, which is an alternative pathway activator. To elucidate this different behaviour of DAF and CD59, C3 step inhibition by the incorporated DAF or CD59 was measured. DAF was effective in the suppression of classical pathway-mediated C3 deposition in Esh, Esw and Egp, but not in Edg, while CD59 exhibited negligible effects in this regard. Next, inhibition of the lysis by CD59 was tested by haemolytic assay. CD59 did not block the C5b-8-mediated lysis in any xeno E. It also barely blocked C5b-9-mediated lysis, except in the case of Egp, in which CD59 partly blocked C9 attack. Membrane constituents on targets other than the incorporated complement inhibitors may be a crucial factor in the induction of cytolysis and, presumably, in hyperacute rejection.

Animals↗