Research in experimental medicine. Zeitschrift fur die gesamte experimentelle Medizin einschliesslich experimenteller Chirurgie最新文献

The quality of sonography of a unilaterally flooded lung needs to be validated on lesions of different echogenicity, size and subpleural position. Lesions were simulated in 12 young pigs with three different methods. After transbronchial (method 1) or transpleural puncture (method 2), diverse substances were injected into the lung. After 4 weeks, the thorax was opened and the lung flooded for the sonographic location of the lesions. In method 3, pulmonary lesions were simulated in an acute experiment after thoracotomy by transpleural injection or by filling of a Fogarty catheter balloon and were located sonographically. Transbronchial injection of alcohol invariably led to subsegment atelectasis. Only 25% of thoracoscopically controlled transpleural injections produced focal lesions in experiments in which the animals survived. Representative lesions were found only after alcohol injections. Transpleural injection of blood or a blood/Echovist suspension (method 3) simulated isoechogenic or echo-rich lesions with indistinct boundaries. By filling a Fogarty catheter balloon with saline solution or Echovist suspension, we succeeded in simulating echo-free or echo-rich lesions with smooth contours, located in different subpleural depths. After unilateral lung flooding, sonography successfully detected the locations of all these lesions and revealed their correlation with functional structures. Sonography of the flooded lung might be helpful in the intraoperative location of lesions, especially in the context of video-assisted thoracoscopic surgery.

The rabbit fetus is one of the most commonly used animal models in experimental studies investigating fetal organ development. However, there is no detailed information about normal growth of organs of rabbit fetuses in English language literature. Fetal rabbits were studied in the second half of gestation between 18th and 30th days. Amniotic fluid volume, body mass (BM), lung, heart and liver masses (LM, HM, LiM), lung and thorax volumes (LV, TV) were determined and LM/BM, HM/BM, LiM/BM, TV/BM and LV/TV ratios were calculated. Additionally fetal lungs were evaluated histologically, BM, LM, HM, LiM and LV were increased until 27th gestational day and then remained unchanged. TV was always increased between 18th gestational day and term. The lung maturation was almost completed in the 27th-28th gestational days. Therefore, BM, LM, HM, LiM and LV are the parameters that can be used to evaluate normal fetal growth between 18th and 27th gestational days. TV seems to be the predictive parameter for evaluation of normal fetal growth during the second half of gestation in rabbit fetuses; 20th and 27th days of gestation are more appropriate for experiments to evaluate lung maturation.

The rate of hepatocyte regeneration at different anatomical locations of the remnant liver after partial hepatectomy was assessed in porcine hepatocytes by bromodeoxyuridine (BrdUr) incorporation and cell cycle kinetics using flow cytometric analysis. Partial hepatectomy was performed in five Yorkshire pigs. A single intravenous injection of BrdUr at 50 mg/kg was administered on the 2nd post-operative day and the animals were sacrificed 1 h later. The remnant liver tissue was harvested and divided into four equal zones, from the liver periphery towards the surgical cut-edge. Biopsy samples were obtained from the centre of each of these zones and similarly from identical anatomical locations in two control pigs that had undergone sham surgery. Hepatocyte nucleus suspension was prepared, double labelled with anti-BrdUr and propidium iodide and analysed by a flow cytometer. The cells in S-phase was used as the parameter to measure the regeneration status. A gradient increase in S-phase from the periphery to the cut edge was observed in all five pigs that had undergone partial hepatectomy. The percentage of S-phase cells in all four zones from the hepatectomy group was significantly higher when compared with that in the controls. Liver regeneration after partial hepatectomy was not uniform but was greatest adjacent to the surgical cut edge and decreased towards the periphery of the liver.

We investigated the effect of antithrombin III on 60 min warm intestinal ischemia-reperfusion (IR) injury in rats. Sprague-Dawley rats, weighing 220-250 g, were divided into three groups: group 1 sham-operated group (no IR injury, n = 8), group 2 ischemic control group (control, Ringer's lactate infused, n = 8), group 3 Antithrombin III treated group (250 U/kg before ischemia, n = 8). Intestinal ischemia was induced in rats by occluding the superior mesenteric artery for 60 min. Malondialdehyde (MDA) levels, myeloperoxidase activity (MPO) and mucosal damage were investigated after 120 min reperfusion. Elevated MDA levels and MPO activity and severe histopathological damage were observed in the control group compared with the sham group (P < 0.05). Decreased MDA levels and MPO activity and less histopathological damage were detected in group 3 compared with the control group (P < 0.05). Accumulation of lipid peroxidation products and neutrophils in mucosal tissues were significantly inhibited by antithrombin III treatment. We conclude that treatment with antithrombin III before intestinal ischemia prevents histological damage in rats.

Our objective was to determine the effectiveness of intraperitoneal single dose piroxicam and low molecular weight heparin (LMWH) on prevention of adhesion reformation in the rat uterine horn. This study was carried out in the Surgical Research Laboratory, at Erciyes University. A standard lesion was created by unipolar electrocautery in 72 uterine horns of 36 female Wistar-Albino rats. After 2 weeks, adhesion formation scores were determined and adhesiolysis was performed in the second-look laparotomy. Animals were then randomly assigned into three groups. Each group contained 12 animals: group 1 was the control group where no adjuvant was given; in group 2, 1 ml 50 U Axa IC/ml solution LMWH was applied to the horns postoperatively, and in group 3, 1 ml 2 mg/ml piroxicam solution was applied to the horns after adhesiolysis. Two weeks later the rats were killed and adhesion reformation was evaluated. The number of horns with adhesion formation and the cumulative scores were not significantly different among the three groups in the second-look laparotomies, but after third-look laparotomies, the number of horns with adhesion reformation, after calculating the extent, severity and total scores of adhesion reformation, was found to be significantly less in LMWH and piroxicam groups than in the control group. Also, the effectiveness of piroxicam was significantly greater in all scores of adhesion reformation than LMWH was. In conclusion, both LMWH and piroxicam doses reduce adhesion reformation in the rat uterine horn, but the effectiveness of piroxicam is significantly greater than that of LMWH.

Articular cartilage serves primarily as a load-bearing material able to regulate its own metabolic activity in response to the mechanical stimuli applied. Fibronectin plays a critical role in the organization and function of the cartilage extracellular matrix. The purpose of this study was to investigate systematically the effect of load magnitude, frequency and duration of loading on the synthesis, content and release of fibronectin and proteins by mature bovine articular cartilage explants using a novel mechanical loading system. Increasing the load magnitude, as well as the duration of loading, inhibited the synthesis and content of fibronectin and proteins; the fibronectin synthesis was more specifically affected than the overall protein synthesis indicating that fibronectin is more responsive to pressure than synthesis of other proteins. Reducing the load frequency did not modulate the inhibitory effect of a given cyclic stress on synthesis and content of fibronectin and proteins even though explants were more compressed. The release of endogenous fibronectin was significantly reduced independent of the applied loading protocols when compared with unloaded controls. This study demonstrates that the magnitude and the duration of loading influences the degree of inhibition of fibronectin and protein synthesis, while loaded explants possess an elevated but limited capacity to bind fibronectin. Compared with other studies, our present results show that the applied load function in particular has a profound effect on the metabolism of chondrocytes.

Carbonic anhydrase (CA) is an enzyme that is expressed in the intestine and catalyzes the reversible hydration of CO2 in the following reaction: CO2 + H2O<==>H2CO3<==>H(+)+HCO3-. To elucidate the association of CA expression with the differentiation of colonic enterocytes, we investigated the expression and localization of CA using a Northern blotting analysis, Western blotting analysis, and immunohistochemical staining. A Northern blotting analysis revealed an abundant expression of CA I and II mRNA in the colonic epithelial cells. However, the expression of CA III mRNA was not detected. According to the results of immunohistochemical staining of the human colonic mucosa using antisera against CA I and II, both CA I and II were localized on the cytoplasm of non-goblet columnar cells in the upper half of the crypts where more differentiated cells are located. According to the results of immunohistochemical staining of the rat colonic mucosa, neither CA I and II were detected at the new-born stage. The expression of CAs in the upper half of the crypts began to rise from 1 week after birth, and thereafter increased according to the growth of the rats. At 3 weeks after birth, the expression of CAs was almost the same as that of the adult rats. The amount of CA proteins evaluated by a Western blotting analysis revealed that the expression of CAs increased gradually until reaching a maximum level at 6 or 8 weeks. These results therefore suggest that CA I and II appear to be good markers for the differentiation of enterocytes in the colonic mucosa.

The study tests the hypothesis that human chorionic gonadotrophin (hCG) alters vascular smooth muscle reactivity by examining the effect of hCG administration on the contractility and relaxation of isolated vascular smooth muscle. Aortic rings from rats pre-treated with intraperitoneal administration of 5,000 I.U of hCG and control animals were contracted to phenylephrine, angiotensin II, CaCl2 and KCl. The experiments with phenylephrine were repeated with rings that were either de-endothelialized, incubated with L-NMMA, or incubated with calcium ionophore A23187. Aortic rings precontracted with phenylephrine were relaxed to acetylcholine (endothelium-dependent), sodium nitroprusside, hydralazine (endothelium-independent) or in the presence of A23187. The contractile responses of aortic rings from hCG-treated animals of phenylephrine, angiotensin II, CaCl2 and KCl were significantly attenuated. This effect was not reversed by pre-treatment with L-NMMA or by de-endothelialisation. In aortic rings from hCG-treated animals, there was almost total inhibition of acetylcholine-induced relaxation, but unaltered relaxation responses to sodium nitroprusside and hydralazine. The inhibitory effects of hCG-treatment on both the contraction and relaxation responses were either fully or partially reversed in the presence of calcium ionophore A23187. These observations suggest that hCG attenuates both contractile and endothelium-dependent relaxation responses by a mechanism which involves inhibition of extracellular calcium ion influx and may indicate a new role for the hormone in the altered vascular responses of both normal and abnormal pregnancies.

In the past, physiological, oncological and pharmaceutical investigations led to the development of different models of enterocutaneous fistulas. For a few years, fistula models were also created to investigate the efficacy of minimal invasive therapies in closing these fistulas. As most experimental surgical procedures are difficult to perform and are often combined with a high mortality or spontaneous closure rate, a new model in mice was developed with the aim of avoiding these disadvantages. Twenty mice, divided into two groups of 10 animals each, had a caecostoma created surgically. The two groups differed regarding the technique of creating the stoma. All animals survived and gained weight during a postoperative period of 4 months. The operation was easy to perform and lasted no longer than about 30 min. Neither a spontaneous closure of the fistula nor any prior death of animals occurred. In conclusion, because of its simplicity and low complication rate, the presented model of an enterocutaneous fistula may offer an interesting alternative to other models for a variety of indications.

In 30% of cases nephrotic syndrome is caused by membranous glomerulonephritis (MG). Protein accumulation in glomeruli leads to progressive loss of kidney function and damage of structure in MG. The role of tissue proteolytic systems and growth factors in this process is not known. The purpose of the study was to estimate urine cathepsin B, collagenase activity and urine excretion of TGF-beta 1 and fibronectin in MG. Cathepsin B activity was greater in the urine of MG patients than in the control group (10.58 +/- 8.73 pmol AMC/mg creatinine per min-1 vs control 7.11 +/- 2.05 pmol AMC/mg creatinine per min-1; P < 0.05). Urine collagenase activity was higher in the group of patients than in the control group (8.59 +/- 4.26 pmol AMC/mg creatinine per min-1 vs control 3.84 +/- 2.09 pmol AMC/mg creatinine per min-1 P < 0.02). Urine excretion of fibronectin (45.60 ng/mg creatinine vs control 10.30 ng/mg creatinine; P < 0.04) and TGF-beta 1 levels in the urine were higher than in controls (283.55 +/- 248.13 pg/ml vs 36.11 +/- 48.01 pg/ml; P < 0.01). Results suggest glomerular overproduction of TGF-beta 1 and urinary leak of proteolytic enzymes (PE). This may result in decreased glomerular PE activity in MG and, with time, may lead to protein accumulation in renal glomeruli and to progressive loss of kidney function and damage of structures as the course of MG progresses. PE urine composition as well as ECM protein and cytokine urine excretion may allow noninvasive glomerulopathy course monitoring in humans in the future.