摘要:

The effects of an atrial natriuretic factor (ANF) infusion upon the production of the arachidonic acid metabolites (thromboxane B2, TxB2; 6-keto-prostaglandin F1α, 6-keto-PGF1α, PGI2, or prostaglandins E2, PGE2) were investigated after acute renal ischemia in the rat. This experimental protocol included a right nephrectomy and a 45-min left renal artery occlusion. Fifteen minutes after declamping, blood samples were collected from the left renal venous effluent for the assay of plasmatic prostanoid concentrations. Three experimental groups were studied: group I (n = 9) sham, no ischemia-group II (n = 9) control group, 45 min of left renal ischemia, followed by a 15-min revascularization, and group III (n = 10) ANF group, a similar ischemic protocol to that in group II was used but, after declamping, synthetic Atriopeptin III was infused (0.5 µg/kg/min) during the 15-min of vascular refiow. Fifteen minutes after declamping, TxB2 secretion significantly increased after ischemia in the control and ANF groups: TxB2: 210 ± 22.4 pg/ml (control group) and 234.8 ± 25.1 pg/ml (ANF group) versus 135.8 ± 17.8 pg/ml (sham group) (p < 0.05 and 0.01, respectively). On the other hand, the 6-keto-PGF1α plasma levels were significantly higher after ischemia in the ANF group (221 ± 34 pg/ml) in comparison with the sham (129 ± 24.1 pg/ml) or with the control group (116.7 ± 12.5 pg/ml). The calculated TxB2/6-keto-PGF1α ratio was therefore higher in the control group, 1.93 ± 0.27, than in physiological conditions (sham group), 1.2 ± 0.17. In the ANF group, on the other hand, the TxB2/PGI2 ratio, 1.13 ± 0.08, was comparable to the basal conditions and therefore lower than in the control group (p < 0.02). The PGE2 concentration increased significantly after ischemia but did not display any difference between the control and the ANF group. These experimental results suggests that the vascular properties of ANF, protecting the ischemically injured kidney, were mediated by an endogenous vasodilating substance production, i.e. PGI2. Usefulness of ANF is therefore postulated in several clinical applications, i.e. kidney tr

ISSN:0014-312X    

DOI:10.1159/000129083

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The effect of the sclerosant 5 % ethanolamine oleate (EO) on renal circulation was evaluated in 20 mongrel dogs into which we injected 5 % EO (0.5 ml/kg) into the superior vena cava. There was a marked hemolysis and a significant decrease in creatinine clearance from 104.4 ± 17.1 (mean ± SD) to 40.7 ± 5.0 ml/min (p < 0.01) at 120 min. The renal arterial blood flow (RAF) decreased biphasically; from 75.3 ± 13.1 to 9.8 ± 9.3 ml/min during an average of 2.3 min, immediately after the injection (p < 0.01) and gradually decreased after reaching the pretreatment level to 43.2 ± 8.6 ml/min at 120 min (p < 0.01). Cardiac output significantly decreased from 1.86 ± 0.08 to 1.54 ± 0.08 1/min (p < 0.01). Tubular necrosis was histologically evidenced in the tissues examined at 6 h after the injection of EO. Biphasic decrease in renal arterial blood flow can be explained by the possible occurrence of spasm of the peripheral renal arteries in the acute phase and tubular necrosis in the late phase. This study suggests to us that the tubular necrosis induced by decreases in RAF as well as hemolytic nephropathy play a significant role in cases of renal dysfunction following the endoscopic injection of 5% EO to sclerose esophageal

ISSN:0014-312X    

DOI:10.1159/000129084

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

We have previously shown that intravenously administered palladium-109 labeled lymphocytes (Pd-L) migrated specifically to peripheral lymphoid organs where they caused selective lymphoid irradiation resulting in significantly prolonged cardiac allograft survival. This study evaluates the biodistribution of subcutaneously injected allogeneic Pd-L and the capacity of such labeled cells carrying a large dose of irradiation at a local site to attract and subsequently delete alloreactive T lymphocytes. It was hypothesized that subcutaneously administered allogeneic lymphocytes labeled with a large dose of palladium-109 will attract and then kill by irradiation the host effector cells which might permit prolongation of donor-specific allograft via partial clonal deletion. The results showed that 80% (injected dose) of subcutaneously injected allogeneic Pd-L remained at the site of administration while 20% of injected dose/gram was localized in the ipsilateral popliteal lymph node. No significant radioactivity was found in the other lymphoid and nonlymphoid organs. Pd-L effectively deleted the donor-specific effector cells, as measured by specific unresponsiveness to donor lymphocytes in mixed lymphocyte reaction. Donor cardiac allograft survival, however, was not prolonged over that found in naive recipient controls, although it was significantly prolonged when compared to cardiac allograft survival in controls sensitized by identical injections of unmodified subcutaneous allogeneic lymphocytes (mean survival time ± SD of 6.5 ± 0.8 vs. 3.0 ± 0.6 days). These results suggest that partial clonal deletion of specific alloreactive cells achieved by this approach alone is insufficient to induce unresponsiveness to allografts in vi

ISSN:0014-312X    

DOI:10.1159/000129085

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Catfish (Ictalurus punctatus) islets were transplanted into the renal subcapsular space of diabetic C57BL/6J mice. The xenograft mean survival time (MST) of islets cultured for 6 days at 24 °C was 4.9 ± 0.5 days, while xenotransplantation of 1-hour-cultured islets did not restore normoglycemia in the diabetic mice. A modest but significant prolongation of the MST was obtained by administration of anti-L3T4 monoclonal antibody to the recipients (13.4 ± 2.1 days). Anti-L3T4 in conjunction with low-temperature culture did not produce a further increase of the MST (9.1 ± 2.7 days). These findings indicate that catfish islets may be a source of islet tissue for transplantation in diabetic recipients. However, procedures that demonstrated to be effective in prolonging the MST of xenografts transplanted across wide species barrier, such as low-temperature culture and anti-L3T4 treatment, failed to prolong markedly the xenograft survival. Further experimental work is needed to study the possibility of improving islets survival after xenotransplantation across distant species barrier (fish to mou

ISSN:0014-312X    

DOI:10.1159/000129086

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

A new impedance analytical system was developed, and measurements were performed over a frequency range of 0–200 kHz by the three-electrode method. The three electrodes consist of a coaxial needle electrode inserted into the tumor and a large reference electrode on the upper abdominal wall. The electrical bio-impedance was measured in 54 patients with breast tumors. The biological tissue can be regarded electrically as an equivalent consisting of extracellular resistance (Re), intracellular resistance (Ri), and electrical capacitance of the cell membrane (Cm). These three parameters were calculated from the measured values of electrical bio-impedance by the curve-fitting technique using a computer program. It was found that Re and Ri of breast cancers were significantly higher than those of benign tumors (p < 0.01), and that Cm of breast cancers was significantly lower than that of benign tumors (p < 0.01). Measurement of the electrical bio-impedance of breast tumors may have value in the differential diagnosis of breast lesion

ISSN:0014-312X    

DOI:10.1159/000129087

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The intestinal absorption of bile acids has so far been studied from the measurement of the biliary secretion after their intestinal infusion. In the present investigation, the ileal absorption capacity for two different bile acids has been evaluated by means of an intestinal perfusion technique and the simultaneous blood drainage from the mesenteric vein corresponding to the isolated loop. Taurocholic acid and unconjugated cholic acid were infused at different concentrations (0.5–10.0 mM), at a flow rate of 4 ml/min/cm intest. Taurocholic acid absorption increased to a maximum with dose, then reaching a plateau, suggesting that a saturable process had taken place. Cholic acid uptake showed a saturable, possibly active, process, together with a nonsaturable one. These results are consistent with the physicochemical properties of the two bile acids. The technique seems so far suitable for the study of the intestinal absorption of substances undergoing the enterohepatic circulation, since it provides a direct measure of the absorbed fraction, without any distortion arising from the hepatic uptake and biliary secretio

ISSN:0014-312X    

DOI:10.1159/000129088

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The changes in the regulation of insulin secretion that accompany sepsis are yet to be fully established. We therefore examined insulin secretion both in vivo and in vitro in 2 different models of peritonitis/sepsis in the rat. Sepsis was induced by intraperitoneal injection of Escherichia coli either alone or together with bile. Following sepsis induction, an initial hyperglycemia developed. This hyperglycemia was transient and had vanished after 3 h (coli group) or 9 h (bile group). However, after 24 h, a second phase of hyperglycemia developed in both groups. The glucose elimination rate after intravenous glucose injection (0.5 g/kg) at 4 and 10 h after peritonitis/sepsis induction was retarded and the hyperglycemia that occurred during intravenous glucose infusion (10 mg/min for 30 min) was exaggerated. This is consistent with a reduced glucose uptake. Simultaneously, the plasma insulin responses to glucose were markedly exaggerated. This could be due to a true potentiated insulin secretion or simply to an adaptation to the hyperglycemia. However, also during intravenous arginine infusion (7 mg/min) at 4 h after peritonitis/sepsis induction, the plasma insulin responses were markedly exaggerated. Since only a slight change in plasma glucose occurred during this challenge, the results suggest that sepsis is accompanied by a true hypersecretion of insulin. To verify whether this is directly or indirectly mediated, pancreatic islets were isolated from peritonitis/sepsis animals at 4 h after disease induction and incubated for 45 min in a KRB medium supplemented with different concentrations of glucose. The subsequent insulin secretion was the same in islets from the septic animals as in controls. Hence, our results show that experimental peritonitis/sepsis in the rat is accompanied by (1) glucose intolerance and (2) a true hypersecretion of insulin which is indirectly mediated.

ISSN:0014-312X    

DOI:10.1159/000129089

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Effects of acute portal hypertension on systemic hemodynamics after hepatectomy were evaluated by portal venous stenosis (PVS) model in dogs. In protocol 1, portal hypertension of about twice portal venous pressure (PVP) decreased cardiac output (CO) and left atrial pressure (LAP) by 24.5% (p < 0.01) and 1.0 mm Hg (p < 0.01), respectively. In protocol 2, stepwise PVS demonstrated that CO change (%) and LAP change (mm Hg) were inversely proportional to PVP change (r = -0.937 and -0.883, respectively). The ratio of CO change to LAP change with stepwise PVS was comparable to that obtained by repeated hemorrhage in protocol 3. The present study shows that low CO with portal hypertension is caused by a reduction of venous return to the heart.

ISSN:0014-312X    

DOI:10.1159/000129090

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0014-312X    

DOI:10.1159/000129091

出版商:S. Karger AG    

年代:1990

数据来源: Karger