Browsing by Author "Silva, Aura"
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- Evaluation of renal injury caused by acute volume replacement with hydroxyethyl starch 130/0.4 or Ringer's lactate solution in pigsPublication . Ferreira, David A.; Cruz, Rita; Venâncio, Carlos; Faustino-Rocha, Ana I.; Silva, Aura; Mesquita, João; Ortiz, Ana L.; Vala, HelenaThis work aimed to evaluate the effects on renal tissue integrity after hydroxyethyl starch (HES) 130/0.4 and Ringer’s lactate (RL) administration in pigs under general anesthesia after acute bleeding. A total of 30 mL/kg of blood were passively removed from the femoral artery in two groups of Large White pigs, under total intravenous anesthesia with propofol and remifentanil. After bleeding, Group 1 (n =11) received RL solution (25 mL/kg) and Group 2 (n = 11) received HES 130/0.4 solution (20 mL/kg). Additionally, Group 3 (n = 6) was not submitted to bleeding or volume replacement. Pigs were euthanized and kidneys were processed for histopathological and immunohistochemical analyses. Minimal to moderate glomerular, tubular, and interstitial changes, as well as papillary necrosis, were observed in all experimental groups. Pre-apoptosis and apoptosis indicators were higher in pigs that received HES 130/0.4, indicating a higher renal insult. Both HES 130/0.4 and RL administration may cause renal injury, although renal injury may be more significant in pigs receiving HES 13/0.4. Results also suggest that total intravenous anesthesia with propofol and remifentanil may cause renal injury, and this effect can be dose related.
- Immunofluorescence method to detect apoptotic events in the duodenum after a situation of hypoperfusion – preliminary resultsPublication . Ortiz, Ana; Vala, Helena; Garcia, Carla; Cruz, Rita; Venâncio, Carlos; Silva, Aura; Ferreira, DavidBackground: Apoptosis plays a key role in intestinal injury, as response to ischemia. In this study, apoptosis in the duodenum after haemorrhage and volume replacement was evaluated with M30, in a pig model. Material and methods: Apoptosis was evaluated in paraffin sections of duodenum from pigs that underwent total intravenous anaesthesia (TIVA) with propofol and remifentanil, and controlled bleeding and volume replacement using Ringer’s lactate (Group1, n=6). Apoptosis was also evaluated in a control group of animals that underwent TIVA, without bleeding (n=6). M30 Cytodeath immunofluorescence assay used a mouse monoclonal antibody (M30clone) (Roche) for detection of a caspase cleavage product of cytokeratin 18. Results: Group1: epithelial cells from the tips of the villi showed strong positive reaction, decreasing towards the body of the villi, negative in crypts and glands. Control group: epitelial cells from the tips of the villi showed a weak positive reaction, also decreasing towards the body and negative in crypts and glands. Discussion and Conclusions: Apoptosis occurred mainly in the epithelium of the villi, appearing to precede intestinal mucosa desquamation. Subsequent studies are being developed to determine the apoptotic index and correlation between immunohistochemical methods in small intestinal segments in the two groups of this study.
- Small Intestine mucosal injury and apoptosis following haemorrhage and volume replacement with different intravenous solutionsPublication . Ortiz, Ana Liza; Vala, Helena; Venâncio, Carlos; Garcia, Carla; Mesquita, João; Silva, Aura; Ferreira, DavidObjective: To characterize mucosal loss (ML) and apoptotic events in the small intestine after haemorrhage and volume replacement with a crystalloid, Lactated Ringers Solution (LR), and a colloid, HES130/0.4 solution, in a pig model. Methods: %ML and apoptotic events at the epithelium of the villi were evaluated in the small intestine from pigs that underwent total intravenous anaesthesia and passive controlled arterial bleeding, followed by volume replacement using LR (group1, n=9) and HES130/0.4 (group2, n=9). Apoptotic events were investigated by performing immunohistochemistry using Cytochrome c antibody and M30Cytodeath immunofluorescence assay. Results: %ML was significantly higher in group1 (P< 0.0001). Similar moderate to intense cytoplasmic immunoreactivity was seen in both groups for Cytochrome c antibody. The median percentage of apoptotic cells in the non-detached villi epithelium was 5.94% (1.46-31.47%) in group1 and 6.38% (0.36-47.48%) in group2. No significant differences were observed between groups. Conclusion: Results suggest that HES130/0.4 administration may more efficiently prevent the acute loss of intestinal mucosa, and, therefore, the integrity of the intestinal barrier. However, the indicators of intestinal apoptosis do not differ between HES 130/0.4 or RL administration.
- The influence of Ringer's lactate or HES 130/0.4 administration on the integrity of the small intestinal mucosa in a pig hemorrhagic shock model under general anesthesiaPublication . Ortiz, Ana Liza; Vala, Helena; Venâncio, Carlos; Mesquita, João; Silva, Aura; Gonzalo-Orden, Jose Manuel; Ferreira, DavidTo determine the effect of fluid resuscitation with 2 different physiological solutions, Ringer's lactate (RL) and hydroxyethyl starch (HES) 130/0.4, on histological lesions of the small intestinal mucosa in anesthetized pigs subjected to severe acute bleeding.