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Biomedical subjects

M Negita

Publications and source records attributed to M Negita.

At least 55 records · Page 3Linked to original sources
PubMed1995

Endothelin-1 and in vitro evidence of renal artery vasoconstriction after liver transplantation.

Twelve pigs underwent orthotopic liver transplantation. The mean endothelin-1 (ET-1) levels in the serum samples of the recipient animals 1 h after reperfusion of the graft (6.2 +/- 1.5 pg/ml) was significantly higher (P < 0.05) than in pretransplantation samples (3.2 +/- 0.6 pg/ml). Serum blood urea nitrogen (BUN) 24 h after transplantation was 13.8 +/- 5.9 mg/dl, which was significantly higher than before transplantation (6.4 +/- 2.2 mg/dl). There was a positive correlation between the serum BUN and ET-1 (r = 0.62, P < 0.05). An in vitro isometric tension study was performed for the contractility response rate of the intact renal artery in the bath chamber containing the serum of the corresponding recipient animals. The mean contractility response rates were higher with the serum obtained after reperfusion of the graft (66.9 +/- 32.4%) than with those obtained before transplantation (18.3 +/- 9.2%) when compared to a standard contractility rate of 100% with 40 mM KCI. Moreover, these contractility response rates were significantly reduced (32.8 +/- 21.0%) with the addition of the ET-1 receptor antagonist FR139317. The results of the present study demonstrated that the liver transplantation was associated with elevation of ET-1 in the serum of the recipient animals. It was considered that ET-1 in the serum caused a direct vasoconstriction of the renal artery in vitro. This may help to explain the renal dysfunction that is often seen in the recipients of clinical liver transplantation.

Animals↗
PubMed1995

[Tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) in transplanted kidneys].

We have studied the involvement of fibrinolysis in acute rejection after kidney transplantation by analyzing changes in urinary levels of substances such as FDP, D-dimer, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI). Fibrinolytic activity was found to be low (that is, PAI is dominant) during acute rejection, and it was elevated (that is, PA became dominant) as acute rejection subsided. It appears that the dominance of PA leads to an increase in the products of fibrinolysis and an elevation in the D-dimer/FDP ratio, resulting in disappearance of the acute rejection. Based on these findings, we thought it necessary to administer t-PA to kidney recipients so that PA becomes dominant earlier and the acute rejection can be reduced. It is necessary for us to directly study the phenomena within the kidneys. Therefore, we recently conducted a histochemical study of the distribution of t-PA, Urokinase type PA (u-PA) and PAI in transplanted kidneys. Transplanted kidney, which functioned well or showed signs of acute or chronic rejection, were biopsied. These renal samples as well as control samples (biopsied from normal nongrafted kidney) were examined as to distribution of t-PA, u-PA and PAI by the indirect enzyme complement method. In conclusion, t-PA, u-PA and PAI were detected in the glomeruli, arterioles, tubule and interstices of the control kidneys, well functioning grafts, acutely rejected grafts chronically rejected grafts. All samples showed intense chromatic responses in the arterioles and part of the tubules. On the whole, the chromatic response tended to be more intense in the acute rejection group than in the other group.

Fibrinolysis↗
PubMed1995

[Clinical study on cerebrovascular diseases after renal transplantation].

Between October 1975 and December 1994, 131 renal transplants were performed on our hospital. Eight of these patients had 9 cerebrovascular diseases, which were 2 cerebral hemorrhages, 5 cerebral infarctions, 2 subarachnoid hemorrhages. Five of the 8 patients whose graft functions were bad died. We studied the relationship of the incidence of these complications to some factors as follows; 1) blood pressure, 2) hypercholestemia, 3) duration of hemodialysis, and 4) graft function. The cerebrovascular diseases after renal transplantation were related to the hypertension after renal transplantation and no correlation with the other factors could be found. Therefore, we think that the control of the hypertension after renal transplantation is the most important for the cerebrovascular diseases and the patient's prognosis.

Adult↗
PubMed1995

[Clinical statistics of 67 cadaveric renal transplantation at the Department of Urology, Kinki University School of Medicine].

A statistic survey was made on the patients undergoing cadaveric renal transplantation between June, 1980 and December, 1993. The total number of patients was sixty-seven. The number of patients per year increased annually. The graft survival rate was 73.8% at 1 year and 63.1% at 5 years. Some transition was seen in immunosuppressive regimens using cyclosporin.

Adolescent↗
PubMed1994

Enhancement of tumor proliferation by cyclosporine A in early phase of experimental hepatic metastasis.

The effect of cyclosporine A (CsA) on in vivo growth of hepatic metastasis was studied. Murine colon 38 tumor cells (1 x 10(5) were inoculated via the superior mesenteric vein. Mice were grouped depending on CsA dosage and time schedules: Group A: CsA 30 mg/kg body weight on the 7, 8 and 9th post tumor inoculation days by gavage; Group B: CsA 15 mg/kg body weight 30 min before tumor inoculation and 2 times more at 24 h intervals; Group C: CsA 30 mg/kg body weight at the same dose timing as Group B. Measurement of the diameter of the largest tumor serially by weekly laparotomy up to 4 weeks revealed that the tumor growth rates were significantly greater in Groups B and C than those in Group A or the control (without CsA). The mean tumor doubling times in the control, and Groups A, B and C were 2.2 +/- 1.3, 2.0 +/- 0.5, 1.5 +/- 0.4 and 1.3 +/- 0.8 days, respectively. The mean tumor numbers of hepatic metastasis were 13.2 +/- 8.3, 11.3 +/- 7.3, 19.4 +/- 8.7 and 19.6 +/- 6.8, respectively. Values of tumor proliferation index obtained by bromodeoxyuridine immunohistochemistry were 10.0 +/- 6.1%, 14.9 +/- 8.0%, 28.6 +/- 8.2% and 30.1 +/- 12.4%, respectively, with significant differences (Groups B and C vs. A or control, P < 0.05). In vitro MTT assay showed that cell viability rates were greater than 100% in the medium containing CsA concentrations of less than 10(-7) mol/liter. However, a cytostatic effect of CsA was apparent at higher concentrations. In contrast to the previous in vivo finding of a cytostatic effect of CsA on tumor cells, we found a cytoproliferative action when CsA was administered early in the course of metastatic tumor implantation in the liver. The mechanism of cytoproliferative effect of CsA is unknown but may involve multiple factors.

Animals↗
PubMed1994

[Ureteral polyps: three case reports].

We observed recently three cases of ureteral polyps including a case of multiple polyps. The first patient was a 33-year-old man with multiple polyps at the left upper ureter. The second patient was a 51-year-old man and the third 49-year-old man, and both cases were complicated with ureteral stones. We divided 88 ureteral polyps reported in Japan from 1970 to 1990 into polyps in children and those in adults. We further divided the individual polyps into single and multiple polyps and examined them clinically. Characteristic findings were obtained in polyps in children; namely, multiple polyps were dominant, almost all of them occurred at the left upper ureter and no cases were complicated with ureteral stones. Furthermore, many of the multiple polyps in adults occurred at the left upper ureter and few were complicated with stones as in the children. In conclusion, the ureteral polyps in children and multiple ureteral polyps in adults were similar in character and we presumed that some congenital factors might be involved in their occurrence.

Adult↗
PubMed1992

[Evaluation of kidney graft function with dynamic MRI--preliminary report].

The value of dynamic magnetic resonance imaging (MRI) in the examination of the function of transplanted kidneys was examined. Dynamic MRI was performed on 14 renal transplant patients. After the injection of Gd-DTPA (dimeglumine gadopentetate), we used small tip angle gradient echo (STAGE) technique with a flip angle of 20 degrees. The cortex was higher in signal intensity of well functioning grafts than the medulla before the injection in Gd-DTPA. Signal intensity of the cortex decreased after 30 seconds. After 1 minute the signal intensity of the cortex recovered and low intensity band meaning passage of Gd-DTPA at corticomedullary differentiation was displayed. Signal intensity of the medulla decreased after 3 minutes. Signal intensity of the parenchyma of transplanted kidney after 5 minutes was much the same as that before injection. Image of poor functioning grafts displayed unclear figures. Time-intensity values of both cortex and medulla in well functioning grafts decreased rapidly after about 2 minutes, and rose thereafter. Time-intensity curves of both cortex and medulla were almost flat on and after 5 minutes. Time-intensity curves of both cortex and medulla in poor functioning grafts were almost flat through out the examination. We concluded that effective parameters of the graft function for the time-intensity curve were delta I1 and delta I2. Dynamic MRI was suggested to be useful in the evaluation of kidney graft function.

Contrast Media↗