Murched Omar Taha

The effect of liposome-delivered prednisolone on collagen density, myofibroblasts, and fibrous capsule thickness around silicone breast implants in rats.

Capsular contracture is a potential adverse effect of breast implants. An inflammatory reaction is most likely the origin of fibrosis around the implant. It is possible that some substances may act to prevent this inflammatory reaction. Thus, our goal was to evaluate the effectiveness of local depot prednisolone phosphate‐liposomes (PPL) on fibrous capsule formation around textured silicone breast implants. Shell prostheses (2 mL) were implanted in the right (plus PPL group) and left (plus saline solution, saline group) subcutaneous dorsum of 18 rats. In another 18 rats, the implants were positioned in the left of the back without any drug instillation (control group). In the PPL group, the capsule thickness (μm) and density (%) of collagen were significantly (p<0.0001) lower compared with the control group on days 35 and 90 postsurgery. Furthermore, in the PPL group, a significant reduction in myofibroblast count was observed on day 90 postsurgery (p<0.0001). In conclusion, a single dose of depot liposome‐delivered prednisolone was effective at impairing capsule formation around the silicone implant. The results suggest a strong local and weak systemic effect of PPL on the fibrous tissue around silicone implants. To our knowledge, no study has yet assessed the effect of PPL on silicone breast implants.

Estudo comparativo do uso de cola de fibrina e cianoacrilato em ferimento de fígado de rato

PURPOSE: To determinate the role of cianoacrilate and fibrin glue in the repair of the hepatic wound, to evidence the hemostatic capacity of the adhesives and their respective integration to the hepatic tissue. METHODS: 30 rats Wistar-EPM1 were separate in 2 groups and submitted to the anesthesia with tiopental in the concentration of 40mg/kg EV. Laparotomy was made with exhibition of the liver. A punch of 3mm was made in the hepatic right lobe. The animals of group A were treated with the placement of fibrin glue in the wounds, the animals of group B had the wounds treated with cianoacrilate. In the 7th of post-operative period, under anesthesia, the animals suffered the resection of the right hepatic lobe and samples were collected for the histology study procedures (HE and Picro-Sirius). They were appraised for optical microscopy, the inflammatory response (qualitative criteria of the neutrofiles presence, giants cells, granuloma, neovascularization) and for polarization microscopy, the quantification of collagen (I-young Type and III-matureType). RESULTS: The two adhesives had hemostatic effects in similar times.The wounds treated with fibrin glue showed larger amount of young and mature collagen and a larger amount of neovascularization, while the wounds treated with cianoacrilate showed larger reaction of granuloma. CONCLUSION: Fibrin glue and cianoacrilate have similar hemostatic effects.The wound treated with fibrin glue present larger neovascularization and larger percentage of collagen type I and type III showing tendency to a better tissue repair without formation of granuloma.

Endothelium-derived nitric oxide (NO) activates the NO-epidermal growth factor receptor-mediated signaling pathway in bradykinin-stimulated angiogenesis

Nitric oxide (NO) is involved in angiogenesis and stimulates the EGF-R signaling pathway. Stimulation of different endothelial cell lines with bradykinin (BK) activates the endothelial NO synthase (eNOS) and promotes EGF-R tyrosine phosphorylation. Increase in NO production correlated with enhanced phosphorylation of tyrosine residues and S-nitrosylation of the EGF-R. NO-mediated stimulatory effects on tyrosine phosphorylation of the EGF-R, where cGMP independent. Inhibition of soluble guanylyl cyclase followed by BK stimulation of human umbilical vein endothelial cells (HUVECs) did not change tyrosine phosphorylation levels of EGF-R. BK-stimulation of HUVEC promoted S-nitrosylation of the phosphatase SHP-1 and of p21Ras. Phosphorylation and activation of the ERK1/2 MAP kinases mediated by BK was dependent on the activation of the B2 receptor, of the EGF-R, and of p21 Ras. Inhibition of BK-stimulated S-nitrosylation prevented the activation of the ERK1/2 MAP kinases. Furthermore, activated ERK1/2 MAP kinases inhibited internalization of EGF-R by phosphorylating specific Thr residues of its cytoplasmic domain. BK-induced proliferation of endothelial cells was partially inhibited by the NOS inhibitor (L-NAME) and by the MEK inhibitor (PD98059). BK stimulated the expression of vascular endothelial growth factor (VEGF). VEGF expression was dependent on the activation of the EGF-R, the B2 receptor, p21Ras, and on NO generation. A Matrigel®-based in vitro assay for angiogenesis showed that BK induced the formation of capillary-like structures in HUVEC, but not in those cells expressing a mutant of the EGF-R lacking tyrosine kinase activity. Additionally, pre-treatment of BK-stimulated HUVEC with L-NAME, PD98059, and with SU5416, a specific inhibitor of VEGFR resulted in inhibition of in vitro angiogenesis. Our findings indicate that BK-mediated angiogenesis in endothelial cells involves the induction of the expression of VEGF associated with the activation of the NO/EGF-R/p21Ras/ERK1/2 MAP kinases signaling pathway.

Oxidative stress gene expression profile in inbred mouse after ischemia/reperfusion small bowel injury

PURPOSE To determine the profile of gene expressions associated with oxidative stress and thereby contribute to establish parameters about the role of enzyme clusters related to the ischemia/reperfusion intestinal injury. METHODS Twelve male inbred mice (C57BL/6) were randomly assigned: Control Group (CG) submitted to anesthesia, laparotomy and observed by 120 min; Ischemia/reperfusion Group (IRG) submitted to anesthesia, laparotomy, 60 min of small bowel ischemia and 60 min of reperfusion. A pool of six samples was submitted to the qPCR-RT protocol (six clusters) for mouse oxidative stress and antioxidant defense pathways. RESULTS On the 84 genes investigated, 64 (76.2%) had statistic significant expression and 20 (23.8%) showed no statistical difference to the control group. From these 64 significantly expressed genes, 60 (93.7%) were up-regulated and 04 (6.3%) were down-regulated. From the group with no statistical significantly expression, 12 genes were up-regulated and 8 genes were down-regulated. Surprisingly, 37 (44.04%) showed a higher than threefold up-regulation and then arbitrarily the values was considered as a very significant. Thus, 37 genes (44.04%) were expressed very significantly up-regulated. The remained 47 (55.9%) genes were up-regulated less than three folds (35 genes - 41.6%) or down-regulated less than three folds (12 genes - 14.3%). CONCLUSION The intestinal ischemia and reperfusion promote a global hyper-expression profile of six different clusters genes related to antioxidant defense and oxidative stress.

Effects of allopurinol on ischemia and reperfusion in rabbit livers.

In this work, we evaluated the effects of allopurinol (ALO), an inhibitor of xanthine oxidase (XO), on hepatic lesions caused by ischemia/reperfusion (I/R) in the rabbit liver. Rabbits were pretreated with ALO (10 mg/kg IV) or saline solution 0.9% before the hepatic I/R procedure. The effects of ALO on hepatic injury were evaluated before and after I/R. A standard, warm hepatic I/R procedure caused profound acute liver injury, as indicated by elevated serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels, as well as a high apoptotic cell count. All of these changes were reversed by the administration of ALO before the hepatic I/R procedure. In conclusion, ALO exerted protective effects on hepatic I/R lesions. This protective effect of ALO was probably associated with blocking the generation of superoxide anions during the hepatic I/R procedure by inhibiting XO activity.

Hyperbaric oxygen therapy protects the liver from apoptosis caused by ischemia-reperfusion injury in rats

The present paper aimed to investigate the role of hyperbaric oxygen treatment (HBO) and the apoptosis in rat liver ischemia‐reperfusion injury (IRI).

Protective Effects of Heparin on Hepatic Ischemia and Reperfusion Lesions in Rabbits

Because the role of heparin (HEP) in hepatic ischemia/reperfusion (I/R) injury is still not fully understood, we investigated the effects of treatment with HEP on hepatic I/R injury in rabbits. For I/R procedures, the portal vein and hepatic artery were occluded by a metallic clamp to promote ischemia. The clamp was removed after 30 minutes to allow reperfusion. Rabbits undergoing the I/R procedure were treated with HEP (100 U/kg) or saline solution 0.9% (SS). When compared with levels before I/R, the serum aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, levels were increased by the hepatic I/R procedure, among rabbits treated with SS or HEP. However, the increase in these enzymes was lower among rabbits treated with HEP. Histologic analysis of hepatic tissue of rabbits undergoing I/R and treated with SS showed marked lesions in the central lobule with significant inflammatory infiltration. In contrast, a significant reduction in lesions caused by I/R was observed in the livers of rabbits treated with HEP. After starting reperfusion, we visualized apoptotic cells with nuclear staining among rabbits submitted to I/R and treated with SS, but not those treated with HEP. These results suggested that HEP was able to attenuate hepatic lesions caused by I/R in the livers of rabbits.

Pretreatment with pentoxifylline attenuates lung injury induced by intestinal ischemia/reperfusion in rats

PURPOSE To investigate the protective effect of pentoxifylline against the lung injury observed after intestinal ischemia (I) followed by a period of reperfusion (R). METHODS Twenty-eight male Wistar rats were equally divided into 4 experimental groups and operated under ketamine-xylazine anesthesia. (1) Sham: falsely-operated animals; (2) SS+IR: intestinal ischemia was accomplished by clipping the superior mesenteric artery during 60 minutes, with an administration of a standard volume of saline solution (SS) 5 min before the end of the ischemia period; the clip was then releases or a 120-min period of reperfusion; (3) I+PTX+R: ischemia as above, PTX was administered (25 mg/kg) and the gut reperfused as above; (4) PTX+I+PTX+R: Five minutes before arterial occlusion PTX was administered; the superior mesenteric artery was then clipped for 60 minutes. After 55-min ischemia, an additional dosis of PTX was administered; the clip was removed for reperfusion as above. At the 60th min of reperfusion a third dosis of PTX was administered. RESULTS PTX markedly attenuated lung injury as manifested by significant decreases (all P<0.001 as compared with the SS+IR group) of pulmonary wet/dry tissue weight ratio, total protein content, myeloperoxidase activity and tumor necrosis factor-alpha. Moreover, it was apparent that in the group PTX+I+PTX+R the improvements have been even more significant. CONCLUSION PTX exerted a protective effect on the lung from the injuries caused by intestinal ischemia/reperfusion.

Evaluation of the longitudinal musculature of segments of the distal colon interposed following extended jejunum-ileum resection.

Several morbid conditions may necessitate extensive intestinal resection, leading to short‐bowel syndrome. When clinical treatment becomes inefficient, a surgical approach is necessary. Distal colon interposition is one of the viable techniques. The interposition of colon segments between remnants of the small bowel improved lifestyle, increased transit time, and diminished diarrhea. The aim of this study is to observe the longitudinal muscular contractions after distal colon interposition. Sixteen male Wistar rats (EPM‐1) were submitted to an 80% small bowel resection associated with a partial colectomy of the distal colon immediately after the bifurcation of the middle colic artery followed by a 3‐cm isoperistaltic distal colon interposition. After 70 days, the animals were submitted to euthanasia and segments of the jejunum, ileum, remnant colon, and interposed colon were prepared for pharmacological tests. The isometric contractions were measured by a poligraph. After 30 minutes, the dose/effect curves were obtained for both metacholine and barium chloride stimulation through the extraluminal surface (serosa). After this period, we observed a significant increase in the length, diameter, and thickness of the intestinal wall. Regarding the sensibility (pD2), no difference was found (interposed colon = 7.21 ± 0.2; remnant colon = 7.65 ± 0.1; remnant jejunum 7.46 ± 0.1; and remnant ileum 7.57 ± 0.1), even though the animals were submitted to different procedures. In relation to the maximal effect (Emax), the longitudinal muscle contraction responses (interposed colon = 11.79 ± 0.1; remnant jejunum = 15.42 ± 0.2; and remnant ileum = 11.48 ± 0.2) were lower than those of the remnant colon (Emax = 22.42 ± 0.1). This means that there was a possible adaptation of colonic segments to their new location.

Sildenafil citrate protects skeletal muscle of ischemia-reperfusion injury: immunohistochemical study in rat model

PURPOSE To investigate the effect of sildenafil citrate (SC) on skeletal muscle ischemia-reperfusion (IR) injury in rats. METHODS Adult male Wistar rats were randomized into three groups: vehicle-treated control (CTG), sildenafil citrate-treated (SCG), and sham group (SG). CTG and SCG had femoral artery occluded for 6 hours. Saline or 1 mg/kg of SC was given 5.5 hours after occlusion. SG had a similar procedure without artery occlusion. Soleus muscle samples were acquired 4 or 24h after the reperfusion. Immunohistochemistry caspase-3 analysis was used to estimate apoptosis using the apoptotic ratio (computed as positive/negative cells). Wilcoxon rank-sum or Kruskal-Wallis tests were used to assess differences among groups. RESULTS Eighteen animals were included in the 4h reperfusion groups and 21 animals in the 24h reperfusion groups. The mean apoptotic ratio was 0.18 ± 0.1 for the total cohort; 0.14 ± 0.06 for the 4h reperfusion groups and 0.19 ± 0.08 for the 24h groups (p<0.05). The SCG had lower caspase-3 ratio compared to the control groups at the 24h reperfusion time point (p<0.05). CONCLUSION Sildenafil citrate administration after the onset of the ischemic injury reduces IR-induced cellular damage in skeletal muscle in this rat hindlimb ischemia model.