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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 847 records · Page 47Linked to original sources
PubMed1988

Myocardial positron tomography with N-13 ammonia in assessment of aortocoronary bypass surgery.

A total of 20 patients were examined at rest and during stress with N-13-ammonia myocardial positron emission tomography (PET) before and after aortocoronary bypass surgery in an attempt to evaluate the effect of surgery on myocardial perfusion and to predict the graft status. The PET images were divided into anterior, septal, apical, lateral and posteroinferior segments for analysis and were evaluated as "normal" (no perfusion defects during stress and at rest), "ischemia" (stress-induced defects) and "fibrosis" (persistent defects both at rest and during stress). Approximately 90% of the segments which were ischemic before surgery became normal after surgery. Thus, ischemic changes are highly reversible, and the vessels perfusing these ischemic areas are most suitable for bypass surgery. However, most of the persistent defects failed to respond to revascularization surgery and, hence, represented irreversibly damaged myocardium. In predicting graft status, graft patency could be demonstrated by normal perfusion in postoperative images (p less than 0.01) or by improved perfusion when pre- and postoperative images were compared (p less than 0.01). However, graft occlusion could not be predicted reliably. This study demonstrated that PET with N-13 ammonia was useful in the assessment of the effects of aortocoronary bypass surgery. However, this technique was not significantly superior to thallium-201 single-photon emission computed tomography for only qualitative analysis.

Adult↗
PubMed1988

Possible involvement of sodium pump in the relaxation of rat aorta induced by alpha-human atrial natriuretic polypeptide.

In order to clarify whether the sodium handling of smooth muscle is associated with the relaxing action of alpha-human atrial natriuretic polypeptide (alpha-hANP), we examined the sodium pump-related effects of alpha-hANP on rat aortic smooth muscles. Application of Ca2+ (1.0 to 10.0 mM) to the muscle preincubated in Ca2+-free, and K+-free or 0.5 mM K+ medium for 60 min induced a contraction. Pretreatment with alpha-hANP (1 x 10(-8) M) decreased the contraction evoked in 0.5 mM [K+]o but not that in K+-free medium. After a contraction was elicited by norepinephrine in K+-free solution, an addition of KCl (1.4-5.4 mM) caused a transient relaxation in a concentration-dependent manner, presumably due to the activation of electrogenic Na pump. The alpha-hANP enhanced the relaxation, which was sensitive to ouabain, and the potentiation by alpha-hANP was inversely related to the concentration of K+ added. When alpha-hANP was applied to relax the muscle precontracted by norepinephrine in the varied concentration of external K+, alpha-hANP-induced relaxation was greater in 1.4 or 2.7 mM [K+]o than in 0 or 5.4 mM [K+]o. These results suggest that the vasodilating effect of alpha-hANP is at least partially mediated by the activation of electrogenic Na, K-pump and this effect is prominent when the Na, K-pump is partially suppressed.

Animals↗
PubMed1988

[Hypomagnesemia following chemotherapy of disseminated testicular tumors].

Sixteen patients with metastatic testicular cancer were treated with combination chemotherapy including cisplatin (CDDP) at 3- to 4-week intervals for two to five courses. There was a sequential fall in serum magnesium with each course of therapy: 13 of the 16 patients (81%) became hypomagnesemic, and the median magnesium nadir was 1.67 mg/dl. Serum magnesium nadir levels gradually decreased according to the cumulative CDDP dose. Acute clinical effects of the hypomagnesemia were observed in 4 patients, 2 of them complained of neuromuscular disturbance in the extremities, one of cardiac arrhythmia, and the other of Raynaud's phenomenon. The median time to the onset of hypomagnesemia was 67 days and the duration of hypomagnesemia was 24 days. The creatinine clearance (Ccr) decreased gradually according to the cumulative CDDP dose, and the mean Ccr declined from 87.2 ml/min before therapy to 55.8 ml/min. In 3 out of 16 patients, an irreversible decrease to below 50 ml/min was seen after chemotherapy. In patients with normal renal function treated by VAB-6 regimen, creatinine clearance (Ccr) decreased transiently during each course of chemotherapy and returned to the pretreatment level during the interval. The mean creatinine clearance declined from 90.7 ml/min before therapy to 82.9 ml/min after three courses of induction chemotherapy. Urinary excretion of beta 2 microglobulin (beta 2MG) increased transiently before Ccr began to decrease during each course of chemotherapy. Serum potassium and calcium concentrations decreased transiently probably due to urinary losses but there was no significant relationship between hypopotassemia, hypocalcemia and hypomagnesemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Chemotherapy of carcinoma of the prostate and testis: experimental study in vivo and in vitro].

Prostate cancer: Considering the stagnation in chemotherapy of prostate cancer in recent years, the following experiments were carried out to determine their clinical value. Surgical specimens from 6 patients, 2 permanent cell lines (EB 33 and PC 93) originated from human prostate cancer and a tumor line serially transplanted in nude mice (PC-NCC) were subjected to chemosensitivity tests such as human tumor cloning assay (HTCA) and/or in vivo tumor growth curve experiments using nude mice. The possible chemosensitive drugs screened by using surgical specimens and PC-NCC tumor were cisplatinum (CDDP), bleomycin (BLM), 5-FU, vincristine (VCR), adriamycin (ADM) and methotrexate (MTX). Most of these drugs were also judged as "effective" by HTCA using a permanent cell line. The minimal discrepancy among them may lead to the conclusion that an in vitro assay using a cell line can substitute for the assay using surgical specimens which can not be obtained frequently. Partly based on the data obtained a chemotherapy regimen, VPM-CisCF, consisting of VCR, peplomycin, MTX, CDDP, cytosine arabinoside (Ara-C) and 5-FU, was designed. The effectiveness of this regimen was demonstrated experimentally. Testis cancer: Two different lines of experiments were performed. A human testicular cancer serially transplanted in nude mice was repeatedly exposed to CDDP in vivo to obtain hyposensitivity to this drug. The synergistic effect of CDDP and VP-16 was demonstrated in the tumor thus obtained. One of its mechanisms has been suggested by partial accumulation of cancer cells in the G1-S and G2-M phase in which CDDP exerts its potential effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The validity of magnetic resonance imaging (MRI) in the staging of bladder cancer: comparison with computed tomography (CT) and transurethral ultrasonography (US).

The magnetic resonance imaging (MRI) of bladder cancer was accomplished in 26 patients who had histologically proven transitional cell carcinoma through transurethral resection. All 26 patients were simultaneously studied by computed tomography (CT) and 21 were also studied by transurethral ultrasonography (US) before surgery or preoperative irradiation. The evaluations of the MRI and CT were carried out by the same radiologist and urologist postoperatively; the evaluation of the US was carried out by several urologists preoperatively, and their results compared with the postoperative pathological findings. The staging accuracy for pT2 tumors and above for each imaging modality was as follows. MRI: sensitivity 83.3%, specificity 71.4%, accuracy 76.9%; CT: sensitivity 58.3%, specificity 42.8%, accuracy 50%; US: sensitivity 100%, specificity 70%, accuracy 85.7%. The results of the staging with regard to extravesical extensions were as follows. MRI: sensitivity 60%, specificity 85.7%, accuracy 80.8%; CT: sensitivity 60%, specificity 81%, accuracy 76.9%. On the other hand, the sensitivity of US was 25%, specificity 94.1% and accuracy was 81%. The higher the pathological staging, the more the diagnostic accuracy was likely to be increased with MRI and CT, but diminished for US. There were three cases of pT1 tumors being over-diagnosed by US, but two of them were accurately staged by MRI. The other 11 cases, diagnosed as T2 or above by US, were only minimally overstaged or understaged by MRI. MRI seemed able to overcome the disadvantage of US which tended to over-diagnose pT1 tumors and which was not suitable for use in diagnosing infiltrative tumors correctly. CT seemed useless for local staging.

Adult↗
PubMed1988

Protein C in human plasma determined by homogeneous enzyme immunoassay with use of a centrifugal analyzer.

We describe the simple and rapid enzyme immunoassay of protein C in human plasma with use of a Cobas Fara centrifugal analyzer. The antibody, labeled with horseradish peroxidase, is reacted with antigen (protein C) for 15 min. The peroxidase activity of the resulting antigen-antibody conjugate is measured at 500 nm for 5 min in the presence of excess H2O2, phenol, and 4-aminoantipyrine, as compared with that of free conjugates. Results are calculated from a stored standard curve and expressed as a percentage of the value determined for a pooled specimen of normal adult plasma. The standard curve is linear from 0% to 200%. The CV is generally less than 4% for different concentrations of protein C. In liver cirrhosis, hepatocellular carcinoma, therapy with warfarin, thrombosis, and disseminated intravascular coagulation, protein C concentrations are about 40-70% of normal. Results obtained with the present homogeneous enzyme immunoassay correlated well with those by enzyme-labeled immunosorbent assay (r = 0.97).

Adult↗
PubMed1988

[Clinical application of MRI for urological malignancy. 1: Usefulness of various imaging modalities for local staging of prostatic cancer; a comparison between MRI, CT and transrectal ultrasonography].

Twenty-three pathologically revealed prostatic cancer patients were examined by magnetic resonance imaging (MRI), computed tomography (CT) and transrectal ultrasonography, (US) and 6 of them underwent radical prostatectomy. A localized prostatic cancer was identified as a low intensity area in the outer zone with high intensity or showed a partial or total destruction of the border line between the internal and the outer zone when cancer invaded into the internal zone from the outer zone, on T2 weighted image of MRI, as we have already reported. On US, a localized prostatic cancer was identified as a hypoehoic area in the outer zone, and showed a heterogeneous image when cancer enlarged. On CT, a localized cancer could not be identified. A diagnostic criteria for local staging by MRI was made and preoperative staging were done in 6 total prostatectomy cases. The accuracy of preoperative staging of cancer seemed to be the highest by MRI, because it was more accurate in diagnosing the extracapsular invasion, seminal vesicle invasion and bladder neck invasion of the tumor than by CT and US.

Aged↗
PubMed1988

[Clinical application of MRI for urological malignancy. 2: Usefulness of various imaging modalities for local staging of bladder cancer; a comparison between MRI, CT and transurethral ultrasonography].

MRI of bladder cancer was accomplished in 28 patients. All of the 28 patients were simultaneously studied by CT, and 22 were also studied by transurethral US before operation. MRI is not as useful as US for local staging of bladder cancer. However, MRI is more useful for diagnosing extravesical extension and covers the deficit of the overdiagnosing tendency of US.

Adult↗
PubMed1988

Enhancing effects of oral adjuvants on anti-HBs responses induced by hepatitis B vaccine.

Hepatitis B (HB) vaccine is very promising for the prevention of HB infection. There exist, however, some non-responders to current vaccination trials. In this study, taurine, parotin and lithium were selected as adjuvants which can be administered orally. The mechanisms of these three materials as adjuvants and their effects on HB vaccine were investigated in mice. For instance, taurine induced polyclonal antibody production and exhibited adjuvant activity. Although taurine did not have any activity on the proliferation of thymocytes nor stimulate IL-2 production, taurine did induce IL-1 production by macrophages. It was considered that taurine-induced IL-1 would play an essential role in the proliferation and differentiation of B cells. Parotin also induced polyclonal antibody production and exhibited adjuvant activity. These effects of parotin were not affected even if macrophages or T cells were depleted, and parotin itself had an IL-1-like activity. Therefore, it was considered that parotin acted directly on B cells by its IL-1-like activity and mitogenic activity, resulting in the proliferation and differentiation of B cells. Lithium induced neither polyclonal antibody production, nor IL-1 or IL-2 production. However, when given with an antigen, lithium activated the humoral immune system, resulting in the augmentation of antibody production. Oral administration of taurine, parotin and lithium were capable of restoring antibody responses to HB surface antigen (HBsAg) in HBsAg-nonresponder mice. Furthermore, taurine, parotin and lithium enhanced the adjuvant effects of aluminium contained in the present HB vaccine. These observations indicate that use of these oral adjuvants may open new perspectives in the field of human HB vaccination.

Adjuvants, Immunologic↗