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Biomedical subjects

A Katayama

Publications and source records attributed to A Katayama.

At least 19 recordsLinked to original sources
PubMed2006

Proteome analysis of human placentae: pre-eclampsia versus normal pregnancy.

Although placental proteins play multiple roles in fetal and placental development and in the maintenance of pregnancy, many remain inadequately characterized. In the present study, we comprehensively analyzed these proteins by using a proteomic approach. Samples were denatured with guanidine hydrochloride, which was found to be superior to the commonly used urea for the present purpose, and subjected to 2-dimensional (2D) electrophoresis (2-DE) to obtain placental proteome maps. The identified protein spots (ca. 60% of the total) on the proteome maps included several pregnancy-related proteins (PRPs). Furthermore, a novel 2D immunoblotting (2-DI) analysis of molecules related to pre-eclampsia revealed three immunopositive spots that appeared to correspond to dynactin p-50, a protein related to cell turn-over. The rate of positivity for dynactin p-50-reactive antibodies was significantly (P=0.0024) higher in 26 pre-eclamptic women than in 58 normally pregnant women. These results indicate that dynactin p-50 may be involved in the pathophysiology of pre-eclampsia.

Adult↗
PubMed2005

Tibial nerve SEPs localized the lesion site in a patient with early tabes dorsalis.

There is controversy regarding the initial pathology of tabes dorsalis. In a patient with early tabes dorsalis, tibial nerve somatosensory evoked potentials elicited normal P15, a delayed traveling peak in the lumbar bipolar leads, and absent subsequent components. Based on the comparison with normative data and stimulation at different intensities, the authors conclude that only the slower conducting antidromic motor volleys are preserved, whereas the dorsal root is damaged at its distal end.

Adult↗
PubMed2005

Occlusal force and condylar motion in patients with anterior open bite.

Patients with open bite often show a weak occlusal force and temporomandibular disorders (TMDs). If these are the main cause of open bite, it may be hypothesized that both pre-pubertal and adult open-bite patients would show a weak occlusal force and abnormal condylar motion. The purpose of this study was to test this hypothesis. Test group subjects consisted of 13 consecutive pre-pubertal and 13 adult patients with anterior open bite. They were compared with age-matched normal subjects. The adult open-bite group showed a weaker occlusal force and a shorter range of condylar motion compared with the control subjects. In the pre-pubertal subjects, however, there were no significant differences in the occlusal force and range of condylar motion between the open-bite and control groups. Therefore, these results suggest that a weak occlusal force or TMDs may not be the main cause of open bite.

Adolescent↗
PubMed2004

Changes in coagulation condition, cytokine, adhesion molecule after repair of type A aortic dissection.

OBJECTIVE: Because residual dissection often exists even after the repair of a type A dissection, we evaluated coagulation conditions, cytokine levels, and adhesion molecule levels in mid-term follow up after repair of type A dissections. METHODS: Thrombin-antithrombin III complex (TAT), D-dimer, soluble interleukin-2 receptor (sIL-2R), soluble intercellular adhesion molecule (sICAM)-1, and type III procollagen peptide (PIIIP) were measured in 12 patients (mean age=63 years) following the repair of a type A aortic dissection at 6-82 months after repair (median=33 months). RESULTS: In the chronic phase, TAT and D-dimer were significantly higher in patients following the repair of a type A dissection compared to healthy controls (TAT; 12+/-8 vs. 2.5+/-1.2 ng/ml, P = 0.0001, D-dimer; 779+/-1384 vs. 104+/-46 U/ml, P = 0.0001). Cytokine was significantly higher in the affected patients (sIL-2R; 556+/-205 vs. 398+/-132 U/ml, P = 0.003, sICAM-1; 255+/-131 vs. 211+/-48 ng/ml, P = 0.136). Collagen turnover (PIIIP) showed a significantly higher value in the affected patients (0.80+/-0.32, vs. 0.58+/-0.13 U/ml, P = 0.002). sIL-2R, sICAM-1 and PIIIP showed a negative correlation with the follow-up period (sIL-2R; r = -0.733, P = 0.0067, sICAM-1; r = -0.61, P = 0.035, PIIIP; r = -0.692, P = 0.0126). We found a positive correlation between aortic size and TAT (r = 0.644, P = 0.0238, n = 12) as well as with D-dimer (r = -0.7831, P = 0.0106, n = 12) and TAT showed significantly higher values in the residual dissection group compared to those without residual dissection (16.6+/-7.9 vs. 7.45+/-4.75 ng/ml, P = 0.035). CONCLUSION: Hypercoagulation conditions continued even after repair. Both TAT and D-dimer would be good indices for following up patients having repaired aortic dissections. Furthermore, cytokine, adhesion molecules, and collagen turnover would return to a stable state unless impairment and expansion of the vessel wall occurred.

Adult↗
PubMed2004

Clinical success of Neoral absorption profile.

We investigated the clinical benefits of cyclosporine microemulsion preconcentrate (CyA-MEPC; Neoral) in 16 de novo renal transplant recipients. The dose of CyA-MEPC was managed from AUC(0-4h), with serial target values of AUC(0-4h) at 5000-->4000-->3000-->2000 ng. hr/mL. The frequency of acute rejection episodes was 25%. The decreased renal function reached a low value of 12.5%, and creatinine was stable. Therefore, setting the target AUC(0-4h) value in the early phase at 5000 ng.hr/mL is an effective strategy to prevent acute rejection episodes. The single dose of Neoral given immediately after the renal transplant was 6 mg/kg (making a daily dose of 12 mg/kg). Thereafter, the dose-normalized AUC(0-4h) was set at a constant value to 4 weeks posttransplant. At week 4, the single dose was decreased to 4 mg/kg twice daily (a daily dose of 8 mg/kg). From these studies a daily dose of 12 mg/kg is suggested to be the appropriate amount for the first dose immediately after transplant. The renal biopsy performed at 6 months posttransplant showed neither cyclosporine-induced renal impairments, nor findings of chronic rejection, suggesting that 2000 ng.hr/mL is an appropriate target AUC(0-4h) value in the maintenance phase. These results suggest that it is possible to set the target value of C2 monitoring in the maintenance phase to a value slightly lower than that proposed from other studies.

Adult↗
PubMed2004

Surveillance of severe invasive group-G streptococcal infections and molecular typing of the isolates in Japan.

The number of patients with severe invasive group-G streptococcal (Streptococcus dysgalactiae subsp. equisimilis) infections has been increasing in Japan. The emm genotypes and SmaI-digested pulsed-field gel electrophoresis DNA profiles were variable among the strains isolated, suggesting there has not been clonal expansion of a specific subpopulation of strains. However, all strains carried scpA, ska, slo and sag genes, some of which may be involved in the pathogenesis of the disease.

Adhesins, Bacterial↗
PubMed2003

Changing prevalent T serotypes and emm genotypes of Streptococcus pyogenes isolates from streptococcal toxic shock-like syndrome (TSLS) patients in Japan.

We surveyed T serotypes and emm genotypes of Streptococcus pyogenes isolates from streptococcal toxic shock-like syndrome (TSLS) patients. T1 (emm1) remained dominant through 1992 to 2000, but the dominant T3 (emm3.1) strains from 1992 to 1995 disappeared during 1996-2000. Strains of several emm genotypes emerged during 1996-2000, indicating alterations in the prevalent strains causing TSLS.

Antigens, Bacterial↗
PubMed2001

Comparative analysis of host responses related to immunosuppression between measles patients and vaccine recipients with live attenuated measles vaccines.

Measles virus infection induces a profound immunosuppression. We analyzed in a time-dependent manner peripheral bloods of one to two-year-old children immunized with live attenuated measles vaccines, compared with age-matched measles patients, for immunosuppression. In contrast to transient severe lymphopenia with measles patients, primarily due to extensive apoptosis of a broad spectrum of uninfected lymphocytes, neither apoptosis nor lymphopenia occurred with measles vaccine recipients. Increase in number and activation of NK cells, which might compensate for the lymphopenia in measles patients, were not found with the vaccinees. While cell surface expression of apoptosis-related molecules such as TNF-related apoptosis-inducing ligand (TRAIL), TRAIL-receptors, CD95(Fas) and Fas-ligand, and plasma interferon-gamma were increased for measles patients, they remained unchanged after vaccination. Plasma interleukin (IL)-18, which is responsible for inducing apoptosis in several infectious diseases, was increased predominantly with measles patients, whereas the increase remained marginal with the vaccinees. IL-10 was elevated transiently in both measles patients and vaccinees. Decrease in plasma IL-12, which is often correlated with T cell suppression, was not found for both cases. Serum IgM and IgG antibodies to measles virus were induced at lower titers in the vaccinees than measles patients. These results indicate that in contrast to wild-type measles virus, live measles vaccines hardly provoked host cytokine responses that lead to apoptotic cytolysis of uninfected lymphocytes, lymphopenia and immunosuppression, and thereby induced weaker immune responses to the virus.

Antibodies, Viral↗
PubMed2001

Human reproductive cloning and related techniques: an overview of the legal environment and practitioner attitudes.

PURPOSE: This study provides an overview of the legal environment and assisted reproductive technology (ART) practitioner attitudes toward human reproductive cloning. METHODS: A review of the law and a survey of ART practitioners and a comparison group of attorneys were undertaken. RESULTS: Human reproductive cloning has been prohibited in many countries, and may soon be prohibited in others. However, many ART practitioners support its use for limited indications. CONCLUSIONS: ART practitioners were surveyed concerning their views on human reproductive cloning and related techniques. A few had considered using or had used embryo splitting or germ cell nuclear transfer. Although they expressed some concerns about the present risk of reproductive cloning, most indicated that it did not violate their religious beliefs. More than three-quarters of ART practitioners responding indicated that they would be willing to provide human reproductive cloning in indicated cases if it were legally permissible to do so. A significant percentage of the group also indicated that they currently have the ability to provide this service.

Attitude of Health Personnel↗
PubMed2001

Chronic cyclosporin nephropathy: long-term effects of cyclosporin on renal allografts.

Cyclosporin (CSA) has significantly reduced both incidence and severity of acute rejection, and brought excellent graft survival rates. Chronic CSA nephrotoxicity seems to be the second most important diagnosis responsible for the late graft failure. CSA-associated arteriolopathy (CAA) is well known as a characteristic lesion of chronic CSA nephrotoxicity by graft biopsies. There are few reports on the long-term outcome of renal transplant patients with biopsy-proven chronic CSA nephrotoxicity after diagnosis of CAA. We conducted two studies, the long-term outcome of the patients with CAA, and the FGS lesion related to CAA. Seventy-four CAA patients continued on CSA therapy after diagnosis of CAA were classified into two groups by outcome of the graft after follow-up: the functioning graft group (n = 30) and the graft-loss group (n = 44). There was no significant difference in severity of CAA grade between the functioning and graft-loss groups. Concomitant lesion of chronic rejection but not severity of CAA was the most important risk factor of graft loss for CAA patients in our study. Of a total of 54 recipients with FGS lesion, 32 patients (59%) were diagnosed as CAA-associated glomerulopathy (CAG) accompanied with severe CAA. Eighteen of 32 CAG patients lost their grafts after follow-up. Their serum creatinine level at biopsy was higher than that of the functioning group; however, there was no significant difference in daily proteinuria at biopsy between two groups. We have tried to reduce CSA dosage to maintain lower blood levels than the usual optimal target levels, but did not discontinue CSA after diagnosis of severe CAA and FGS lesion. In 15 isolated pure CAG patients, those with increasing daily proteinuria exceeding 2 g lost their graft function even after reducing CSA administration. The change in daily proteinuria seems to be a useful indicator for late graft loss in the patients of FGS lesion with severe CAA. CAA is not specific for chronic CSA nephrotoxicity, and FGS lesion is also a non-specific lesion often developed in renal allografts. Our study revealed clinicopathological characteristics of chronic CSA nephrotoxicity. Isolated chronic CSA arteriolopathy of severe degree has a fairly good prognosis under controlled CSA therapy. FGS lesion accompanied by CAA is considered as a new concept of CAG, and increasing proteinuria in patients with CAG is a good indicator for poor outcome. These results will contribute towards an appropriate therapeutic plan for renal transplant patients undergoing long-term CSA treatment.

Adult↗
PubMed2001

Does infiltration of neutrophils in peritubular capillaries indicate humoral rejection? A case displaying a characteristic lesion of a significantly high amount of neutrophils in peritubular capillaries at 1-h graft biopsy during transplant operation.

We present a case report of a 50-yr-old Japanese woman with a significant accumulation of neutrophils in the peritubular capillaries (PTC) and severe acute tubular necrosis (ATN) at 1-h allograft biopsy during transplant operation from cadaver donor after a cardiac death. Significant accumulation of neutrophils in the PTC is usually valuable diagnostically for acute humoral rejection. However, the patient showed no clinical signs of acute rejection. A second graft biopsy performed on the fifth postoperative day (POD) revealed that both infiltration of neutrophils in PTC and ATN lesions were more aggravated. Neither clinical course nor other morphological findings were compatible with humoral rejection. After the third biopsy of POD 27 revealing acute vascular rejection of moderate degree, acute rejection therapy using methylprednisolone pulse therapy and OKT-3 therapy was performed. Consequently, after a period of delayed graft function requiring haemodialysis for approximately 4 wk, graft function was restored and serum creatinine decreased to 2 mg/dL. Later, we were able obtain information from a paired graft from the same donor. Significant accumulation of neutrophils in the PTC similar to our recipient was also noted in a 1-h biopsy specimen of the paired kidney. This confirmed that the accumulation of neutrophils in the PTC noted in two recipients was transmitted from the donor kidney. The pathogenesis and clinical significance of neutrophils in the PTC has been shrouded in mystery.

Biopsy↗
PubMed2001

More than 1,000 cases of total parathyroidectomy with forearm autograft for renal hyperparathyroidism.

Between March 1981 and December 2000, we performed 1,053 total parathyroidectomies with forearm autograft for advanced renal hyperparathyroidism (HPT). Based on histopathologic and pathophysiologic investigations, surgical treatment should be considered when parathyroid glands show nodular hyperplasia. Measuring parathyroid volume by ultrasonography was useful to detect nodular glands and to determine surgical indications. The clinical effect of parathyroidectomy on the symptoms and biochemical variables was striking. Skeletal deformity, progressive bone loss, and vessel calcification leading to high mortality risk could not be alleviated by even successful surgery, however. To prevent cardiovascular complications, parathyroidectomy should be performed in the relatively early stage of renal HPT. Total parathyroidectomy with forearm autograft is a suitable procedure for renal HPT, especially in patients who require long-term hemodialysis. For surgeons, it is important to remove all parathyroid glands, including supernumerary glands, at the initial operation and to choose adequate parathyroid tissue for the autograft to prevent persistent and recurrent HPT. Although the risk of graft-dependent recurrent HPT is not negligible, enlarged transplanted parathyroid tissue can be removed easily and noninvasively from the forearm under local anesthesia. There is no risk of hypofunction of the autograft.

Adult↗
PubMed2001

Osteoprotegerin levels before and after renal transplantation.

Osteoprotegerin (OPG) is a newly identified glycoprotein that belongs to the tumor necrosis factor receptor superfamily and regulates bone mass by inhibiting osteoclastic bone resorption. The regulatory mechanism of OPG is still unclear after successful renal transplantation (RTX), however, resulting in resolution of uremia. The present study was designed to clarify the potential role of OPG in uremia and after RTX under immunosuppressive therapy. We evaluated circulating OPG levels by measuring them before and after RTX (postoperative days 2, 14, and 28). Our protocol of immunosuppressive drugs was dual therapy using cyclosporine and steroids. Serum OPG was quantitated using enzyme-linked immunosorbent assay. After successful RTX, serum OPG levels decreased significantly on day 14 and day 28 compared with the baseline level (P < 0.05). Creatinine clearance dramatically increased until day 14 and decreased thereafter. Serum OPG declines for the first 2 weeks after RTX owing to functioning allograft and decreases again for the next 2 weeks because of steroids and possible immunosuppressive agents.

Adult↗
PubMed2000

Mapping of subunit-subunit contact surfaces on the beta' subunit of Escherichia coli RNA polymerase.

The RNA polymerase core enzyme of Escherichia coli with the catalytic activity of RNA polymerization is assembled sequentially under the order: 2alpha --> alpha(2) --> alpha(2)beta --> alpha(2)betabeta'. The core enzyme gains the activities of promoter recognition and transcription initiation after binding the sigma subunit. The subunit-subunit contact surfaces of beta' subunit (1407 residues) were analyzed by testing complex formation between various beta' fragments and either the alpha(2)beta complex or the sigma(70) subunit. Results indicate that two regions, one central region between residues 515 and 842 and the other COOH-terminal proximal region downstream from residue 1141, are involved in binding the alpha(2)beta complex; and the NH(2)-terminal proximal region between residues 201 and 345 plays a major role in binding the sigma(70) subunit. However, both alpha(2)beta binding sites have weak activity of the sigma(70) subunit; likewise, the sigma(70) subunit-contact surface has weak binding activity of the alpha(2)beta complex. The sites involved in the catalytic function of RNA polymerization are all located within two spacer regions sandwiched between these three subunit-subunit contact surfaces.

DNA-Directed RNA Polymerases↗
PubMed2000

Acute humoral rejection of kidney allografts in patients with a positive flow cytometry crossmatch (FCXM).

The patients with a positive flow cytometry crossmatch (FCXM) are categorized as a high-risk group causing hyperacute or accelerated acute rejection after kidney transplantation. According to the successful results of ABO-incompatible renal transplantation, we have performed the living related transplant operations in the recipients with positive FCXM for donor T cells, but having a negative complement-dependent lymphocytotoxic reaction test. We have followed the clinical course of 4 FCXM-positive patients, and 2 of them have developed acute humoral rejection. We report the strategies for FCXM-positive living kidney transplantations and the characteristics of pathological findings of acute humoral rejection in FCXM-positive renal transplants. We have had few episodes of acute humoral rejection in ABO-incompatible kidney transplantations under immunosuppressive regimens, including cyclophosphamide, but 2 patients of 4 with FCXM-positive kidney transplantations developed acute humoral rejections. The differences in immunosuppressive regimen between ABO-incompatible and FCXM-positive kidney transplantations concern anti-lymphocyte globulin (ALG) and splenectomy. We have not performed splenectomy and ALG administration in FCXM-positive kidney transplantations. Severe acute rejection episodes have been experienced on post-operative days 7 and 9 in 2 of 4 FCXM-positive recipients. The early acute rejection episodes were clinically and pathologically diagnosed as typical humoral rejections. We have examined an immunofluorescent study to prove the diagnosis of humoral rejection in FCXM-positive kidney transplantations; both immunoglobulin M and C3 were positive for the whole course of humoral rejection. The 2 patients with acute humoral rejection recovered after treatment with double filtration plasmapheresis or plasma exchange to remove their anti-donor antibodies. The gold standard of success in FCXM-positive kidney transplantations is to suppress the production and reduce the level of anti-donor antibodies after transplant operations.

ABO Blood-Group System↗