摘要:

In a porcine model of endotoxemia we have studied the effects of nitric oxide (NO) on hepatic oxygen delivery and consumption. After 3 h of endotoxemia, NO biosynthesis was modulated by a bolus dose of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). Fifteen minutes thereafter a continuous infusion of the NO donor sodium nitroprusside (SNP) was started. Endotoxin significantly reduced hepatic oxygen delivery from 3.4 ± 0.6 to 2.2 ± 0.3 ml/kg/min at 3 h. Due to an increased extraction ratio (ER), oxygen consumption was nearly unaffected. L-NAME further diminished oxygen delivery to 1.0 ± 0.2 ml/kg/min within 15 min (p < 0.05), but despite an increase in ER from 47 to 68% (p < 0.05), oxygen consumption tended to decrease (from 1.0 to 0.7 ml/ kg/min, nonsignificant). A similar tendency was observed in a control group of 9 pigs which was treated in the same way as the study group, except for the SNP infusion. SNP induced an almost selective increase in hepatic arterial flow, with a corresponding increase in oxygen delivery to 1.8 ± 0.3 ml/kg/min (p < 0.05). At the same time ER was reduced from 68 to 42% (p < 0.05). Oxygen consumption remained unaltered. The control group exhibited no change in either oxygen delivery or consumption. The study shows that nonselective inhibition of NO synthesis is detrimental to hepatic perfusion and oxygen transport. The NO donor SNP increased oxygen delivery via a selective increase in hepatic arterial flow, but failed to influence oxygen consumption. This was probably mainly due to a massive shutdown of sinusoids, which did not reopen when flow was increased. A functioning microcirculation thus seems to be a prerequisite for the stimulation of organ blood flow to be effect

ISSN:0014-312X    

DOI:10.1159/000129529

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Background: In the present study a technique for isolated perfusion of rat intestines in vitro should be tested as an evaluative tool in the assessment of intestinal alterations related to ischemia and reoxygenation. Methods: Segments of upper jejunum (15 cm) were isolated from Wistar rats with vascular pedicle (superior mesenteric artery, SMA and portal vein). The SMA was cannulated with polyethylene tubing and flushed with 10 ml of University of Wisconsin (UW) preservation solution. The intestinal lumen was rinsed with 10-15 ml of UW solution and the organ was stored immersed in UW solution at 4¤ C for 4 or 18 h. After cold ischemic storage structural and functional integrity of the preparation was tested by biluminal perfusion with artificial buffer via SMA (5 ml/min modified Krebs-Henseleit buffer, 200 mg% glucose, 5% dextran 78,0.06 mg% dexamethasone, 7 mg% atropine to counteract paralytic hypersecretion) and the intestinal lumen (0.5 ml/min NaCl 0.9% with 200 mg% of galactose). The in vitro model was validated by perfusion of control preparations harvested without ischemic alteration. It was seen that ischemic preservation of 4 h had only a minor impact on the recovery of cellular ATP content and enzyme release (LDH) upon reperfusion, whereas both parameters were significantly changed after 18 h of preservation. Functional parameters like transmucosal carbohydrate absorption and luminal water balance, however, were significantly impaired already after 4 h of ischemic storage of the gut, thus yielding sensitive criteria for the appreciation of the postischemic integrity of the gut. Conclusions: It is concluded that the isolated gut preparation, being an inexpensive and technically feasible model, may be a useful tool in experimental research of intestinal ischemia/reperfusion

ISSN:0014-312X    

DOI:10.1159/000129530

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Skeletal muscle is frequently damaged by ischemia-reperfusion both caused by direct injury and also by surgery. The purpose of the present experiments was to examine how the different types of skeletal muscles (fast and slow) react functionally and morphologically after 1 and 2 h of ischemia followed by different periods of reperfusion. The fast-twitch (musculus extensor digitorum longus, EDL) and the slow-twitch (muscu-lus soleus, SOL) muscle of Wistar rats were prepared. They were stimulated in vivo, either directly or indirectly at different reperfusion times following tourniquet ischemia, and the contraction force of the muscles was recorded. The morphological changes were examined by light microscopy. At early reperfusion times, the contraction force of the EDL muscle was reduced by 40 and 90% after 1 and 2 h of ischemia, respectively. The contraction force was about 50% at the end of a 2-week reperfusion period in the 1-hour ischemia group and it increased significantly (from 5 to 38%) during the second week if the ischemia lasted for 2 h. Reduction of contraction force in the SOL muscle was over 50 and 90% following 1 and 2 h of ischemia, respectively, and it started to improve from the 2nd week. Morphological changes of the two types of muscle were identical. At early reperfusion times granulocytes were seen in the blood vessels adhering to the endothelium. 24 h later neutrophil granulocytes migrated into the endomysium and thereafter into the perimysium. One week after 1 h of ischemia both muscles showed normal histology. However, the structural regeneration process only started at the end of the 1st week of reperfusion after 2 h of the ischemic damage. The following conclusions can be drawn.There is functional morphological evidence of ischemic and reperfusion injury in both muscles after 24 h and also after 1 week of reperfusion.Functionally, the two types of muscles regenerate differently, i.e. the SOL starts to regenerate earlier than the EDL. Morphologically the two types of muscle show the same reactions. An increase in the time of ischemia from 1 to 2 h delays the regeneration processes.

ISSN:0014-312X    

DOI:10.1159/000129531

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The objective of this study was to assess the protective capacity of UW solution in comparison to Bretschneider’s (HTK) cardioplegic solution under moderate hypothermic conditions (25 ° C), as those usually present during intraoperative myocardial protection. Ischemia-induced alterations of cardiac function parameters were analyzed and compared for each solution after 45 min of ischemic storage and 60 min of reperfusion with oxygenated Krebs-Henseleit buffer (KHB), using a rat working-heart model. Compared to nonischemic values, left-ventricular systolic and diastolic pressure, +dp/dtmax and -dp/dtmax were significantly better maintained in the HTK (95 mm Hg, 7 mm Hg, 2,657 mm Hg/s and 2,122 mm Hg/s) than in the UW group (76 mm Hg, p < 0.05, 11 mm Hg, p < 0.05, 1,745 mm Hg/s, p < 0.05 and 1,600 mm Hg/s, p < 0.05). Concerning the myocardial contents of ATP, creatine phosphate and the energy charge, a minor decrease was observed after preservation in HTK compared to UW solution. The results of this study indicate superior myocardial protection with the use of HTK solution for protection of the heart at 25 °C compared to UW solut

ISSN:0014-312X    

DOI:10.1159/000129532

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The ligation of portal branches is known to induce an atrophy of the deprived lobes and a hypertrophy of the nonligated lobes. In this work, we examined if this response occurs when the ligation affects 90% of the liver mass and if it is able to influence the survival rate after a hepatectomy of this magnitude. In male Wistar rats, major portal branches were ligated, keeping open only a small branch supplying the papillary lobes. The ligated lobes underwent a progressive weight loss and their DNA synthesis remained at the level of the controls. The nonligated lobes started to gain weight on the first postoperative day and had increased about 5-fold by the 14th day. The DNA synthesis in these lobes was greatly enhanced with a peak increase at 24 h. Two weeks after a similar ligation of portal branches, the ligated lobes, representing initially 90% of the liver mass, were resected and 80% of the rats survived. In the control group submitted only to a sham operation 2 weeks before, all rats died within 48 h after resection of the corresponding lobes. These results demonstrate that ligation of portal branches feeding 90% of the liver mass can be well tolerated and induces an atrophy of the ligated lobes and a hypertrophy of the nonligated lobes. This procedure, which improves the survival rate after an extended hepatectomy performed 2 weeks later, could find some clinical application.

ISSN:0014-312X    

DOI:10.1159/000129533

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The aim of this study was to determine the effect of portal hypertension (PHT) on gastric mucosal glycoproteins in rats. PHT was induced experimentally by partial ligation of the portal vein (PVL) in 20 male Wistar rats: 10 rats (PVL4 group) were analyzed after 4 weeks and the remaining 10 (PVL8 group) after 8 weeks. In another group of 10 rats (control group), sham operations were performed. The severity of gastric mucosal lesions was evaluated macroscopically by a gross ulcer index. The gross ulcer indices in the PVL groups were significantly higher than those in the controls (p < 0.05). Histomorphometric evaluation of the intraepithelial mucin content, with the periodic acid-Schiff-Alcian blue staining technique, confirmed a significant decrease in mucosal glycoprotein production in the PVL groups (p < 0.05). Quantitative changes in gastric mucosal hexosamines were also used for mucosal glycoprotein analyses, and the hexosamine content of the gastric mucosa in the control, PVL4 and PVL8 groups were 300.7 ± 7.8, 177.2 ± 4.9 and 169.1 ± 3.5 µg/l00mg dried mucosa, respectively. The gastric mucosal hexosamine content was significantly lower in the PVL groups than in the control group (p < 0.05). No significant differences were observed between the two PVL groups in the above-studied parameters. These findings reveal that PHT causes a decrease in gastric mucosal glycoproteins in rats, and the decreased mucin content may weaken an important defensive factor of gastric mucosa. We suggest that gastric mucosal glycoproteins may play an important role in the pathogenesis of gastric mucosal lesions from

ISSN:0014-312X    

DOI:10.1159/000129534

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

In patients with gastric cancer, distal pancreatectomy was frequently performed for complete removal of the lymph nodes along the splenic artery, but this procedure semetimes induced pancreatic juice leakage, subphrenic abscess, and postoperative diabetes. To avoid these complications, pancreas-preserving total gastrectomy (PP) was developed by Maruyama et al. [World J Surg 1995;19:552-536], with which the spleen, splenic artery, and fatty connective tissue including lymph nodes could be removed completely without distal pancreatectomy. From 1988 to 1995, 36 patients underwent PP in our department. Although there were no operative deaths and no patient developed postoperative diabetes, pancreatic juice leakage was observed in 4 patients (11.1%). We assumed that ischemia of the distal pancreas may have caused this pancreatic juice leakage and investigated the relationship between pancreatic blood flow (PBF) and this complication in 12 recent patients. A significant negative correlation between PBF in the pancreatic tail and the peak amylase level (PAL) in the drain fluid was demonstrated. Two patients with PBF values of 4.5 and 5.2 ml/min/100 g tissue, respectively, and a PAL of more than 2 × 105 U/l developed pancreatic juice leakage, whereas the 10 patients without this complication had PBF values above 6 ml/min/100 g tissue and a PAL of less than 2 × 104 U/l. These results suggest that measurement of PBF may be useful to predict the leakage of pancreatic juice after PP and that distal pancreatectomy may be preferable when PBF is extremely lo

ISSN:0014-312X    

DOI:10.1159/000129535

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Vaccination with gene-transfected tumor cells has recently been proposed as a new strategy in the immunotherapy of cancer. Since autologous tumor cells provide an optimal antigen profile, the possibility of generating single cell suspensions from renal cell carcinoma (RCC), malignant melanoma (MM), colon carcinoma (CC), and non-small-cell lung cancer (NSCLC) biopsies was investigated. One hundred and seventy-four tumor biopsies were processed by mechanic and enzymatic dissociation, yielding 1-2 × 106 107 cells were established from 29 of 86 (34%) RCC, 14 of 38 (37%) MM, 11 of 23 (48%) NSCLC and 4 of 27 (15%) CC specimens. The amount of non-tumor cells, as assessed by morphology and immunocytology, was generally low ( 107 cells were obtained in 73% of MM with a high degree of vascularization and in 22% of MM with a low degree of vascularization (p 107 70%, respectively, in samples with a high degree of vascularization generated by an optimized biopsy technique excluding necrotic parts

ISSN:0014-312X    

DOI:10.1159/000129536

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

A retrospective study was conducted in search of an optimal surgical procedure for early cancer of the proximal stomach. The clinicopathological findings and survival data of 128 patients operated on during a recent period of 16 years were analyzed. Nodal metastasis was found in 12% of the patients and had a significant influence on the survival. It was more frequently observed in the undifferentiated type, regardless of the tumor size. Most metastases were found in the proximal paragastric nodes, and no metastasis was observed in the pyloric region or at the splenic hilum. These facts suggest that while the resection of paragastric nodes is advocated, neither total gastrectomy nor splenectomy is required simply for the purpose of lymphadenectomy.

ISSN:0014-312X    

DOI:10.1159/000129537

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Octreotide, the long-acting somatostatin analogue, has been reported to modulate gastrointestinal motility in both animals and humans. A role in colonic peristalsis and a possible clinical application in common disorders, such as chronic constipation and irritable bowel syndrome, have not been evaluated. It has been previously suggested that octreotide promotes the descending relaxation of the peristaltic reflex arc. We hypothesized that this effect may involve inhibition of the motility index (MI) of the distal colon. To test this proposal, we studied peristalsis in isolated rabbit colons and also in the intact distal colons of anesthetized rabbits undergoing octreotide administration. Left colons of New Zealand white rabbits were harvested, placed in an isolated organ chamber and perfused with Krebs-Ringer bicarbonate solution via the inferior mesenteric artery. In a separate preparation, the colons were left in situ. Motility was quantified with a 6-port continuous infusion manometry catheter. The MI (mm Hg/min) was calculated by integration of the area of the digitalized signal (8/s), which reflected high-pressure peaks of different magnitudes. High-pressure waves were defined as >20 mm Hg. Octreotide was infused via the inferior mesenteric artery in the isolated specimen or the lateral ear vein in the anesthetized animals in concentrations of 10–12 to 10–6M. Octreotide inhibited high-pressure waves in a dose-dependent manner. These effects resulted in a decreased MI, with the maximum inhibition of 24.6% at 10–11M (p 20 mm Hg were reduced by 62.2%. The data indicate that octreotide decreases the MI by inhibition of high-pressure waves in the distal rabbit colon. These findings are consistent with the proposal that somatostatin may augment descending relaxation of the peristaltic reflex arc. This effect is independent of neural modul

ISSN:0014-312X    

DOI:10.1159/000129538

出版商:S. Karger AG    

年代:1997

数据来源: Karger