Marina Rodrigues Garcia da Silveira

Effect of hyperbaric hepatic hyperoxia on the liver of rats submitted to intermittent ischemia/reperfusion injury

PURPOSE To determine the effect of hyperbaric hyperoxia as hepatic preconditioning on hepatocellular integrity in rats submitted to intermittent hepatic ischemia/reperfusion injury. METHODS Twenty male Wistar rats were divided into 4 groups (SHAM, I/R, HBO-I/R and CONTROL). The surgical technique consisted of total clamping of the hepatic pedicle for 15 min, followed by reperfusion for 5 min, performed twice. The application of hyperbaric oxygen (HBO) was carried out in a collective chamber (simultaneous exposure of 4 rats) pressurized directly with oxygen at 2 ATA for 60 min. Tissue malondialdehyde (MDA) levels were determined and blood samples were collected for the determination of serum AST and ALT levels. Data were analyzed statistically by the Mann-Whitney test, with the level of significance set at p < 0.05. RESULTS A statistically significant difference in MDA (p< 0.05) was observed between control and HBO-I/R, but not between control and I/R. Regarding AST, there was a difference between control and I/R and HBO-I/R. Analysis of ALT revealed a significant difference between control and I/R (p<0.05) and between I/R and HBO-I/R, with no difference between control and HBO-IR. CONCLUSION Hyperoxic preconditioning proved to be favorable regarding alanine transaminase, but not aspartate aminotranserase or malondialdehyde levels.

Effects of hyperbaric oxygen therapy on the liver after injury caused by the hepatic ischemia-reperfusion process

PURPOSE To evaluate the effects of hyperbaric oxygen on rats submitted to hepatic ischemia and reperfusion. METHODS Twenty-three Wistar rats were divided at random into 3 groups: SHAM, rats submitted to surgical and anesthetic stress without induction of hepatic ischemia/reperfurion; I/R, rats submitted to total ischemia of the hepatic pedicle for 25 min followed by 5 min of reperfusion; HBOI/R, rats submitted to 60 min of hyperbaric oxygen therapy at a pressure of 2 absolute atmospheres immediately after the experimental protocol of ischemia/reperfusion. Hepatic function was evaluated by quantitation of serum alanine aminotranferase (ALT) and aspartate aminotransferase (AST), and by mitochondrial function through the determination of states 3 and 4 of mitochondrial respiration, respiratory control ratio (RCR) and mitochondrial swelling. Data were analyzed by the Mann-Whitney test, with the level of significance set at p <0.05. RESULTS There was a significant difference in state 3 values for the SHAM group vs I/R and I/R vs IRHBO, in state 4 values for the SHAM group vs I/R; and in mitochondrial swelling for the SHAM groups vs I/RHBO, SHAM vs I/R, and IR vs I/RHBO. CONCLUSION The use of hyperbaric oxygen after I/R improved in a relative manner both the production of energy and the effects on the mitochondrial wall.

Effect of irradiation with different laser wavelengths on oxidative stress of non-hepatectomized rats

PURPOSE To assess the effect of two laser wavelengths, either separate or combined, on intact rat livers. METHOD Nineteen male Wistar rats (200-300 g) were submitted to laser irradiation at 5 different sites on the liver surface.Wavelengths 660 and 780 nm were used, with a dose of irradiation of 60 J/cm2/site.The animals were divided into the groups:control (C) and animals irradiated with 660 nm laser (L1), with 780 nm laser (L2) or withboth wavelengths (L3).Mitochondrial function, mitochondrial swelling, and hepatocellular malondialdehyde (MDA) levels were determined.Data were analyzed by the Mann-Whitney test, with the level of significance set at 5%. RESULTS There was a reduction of ADP-activated respiration (state 3) in group L1 compared to group C (p=0.0016), whereas the values of group L2 were similar to control.Group L3 also showed a reduction of state 3 (p=0.0159).There was a reduction of RCR in group L1 compared to control (p=0.0001) and to group L2 (p=0.0040).Mitochondrial swelling only differed between group L3 and control (p=0.0286).There was a increase in MDA levels in group L3 compared to control (p=0.0476) and to group L2 (p=0.0286) and in group L1 compared to group L2 (p=0.0132). CONCLUSION Although laser irradiation reduced mitochondrial function,it did not interfere with the hepatocellular energy status.

XIV International SOBRADPEC Congress and Translational Research Forum Effective and interconnected participation of undergraduates and postgraduates in scientific investigation

we commented about the characteristics of the XIV International SOBRADPEC Congress and Translational Research Forum and regarding the approach to translational surgery and its insertion in current medical education as a generator of medical knowledge, as well as its importance in the teaching and learning process for both students and professors of medicine. In the present editorial, we shall now present some considerations regarding the profile of the authors of full papers published in these supplements of the XIV International SOBRADPEC Congress and Translational Research Forum chaired by Prof. Dr. Lydia Masako Ferreira, full professor of Escola Paulista de Medicina-UNIFESP. Thirty-eight full papers submitted by the authors were selected for this congress for publication in the three supplements of Acta Cirurgica Brasileira, as well as 150 abstracts to be presented during the Event as posters or as oral presentations and to be published in the annals of the congress.As shown in Figure 1, an initial analysis of the 38 original full papers selected for the supplements shows that 51% of the authors are professors of medicine, 21% are postgraduate students, 12% are undergraduate students, and only 2% are medical residents. The participation of undergraduates in scientific investigations is striking and leads us to reflect about the real interest of students in starting to work in research in a professional manner under the guidance of a professor of medicine as an adviser. Most of these students actively participated in the composition of the articles from data collection to the final writing, a fact that fully justifies their authorship or co-authorship, with merit. In addition, integration was observed between undergraduate and postgraduate students, as demonstrated by the distribution of the authors of the articles (Figure 1).Regarding sex distribution, it can be seen that there was a clear prevalence of females among the undergraduates, whereas males significantly prevailed among the residents, with a six to one proportion. In contrast, the proportion of males and females was similar among postgraduates and professors, (Figure 2). This observation agrees with the literature, which shows that the number of women entering medicine in Brazil has been higher than the number of men since 2009

Investigations with interinstitutional participations, a significant milestone of the International SOBRADPEC Congress and Translational Research Forum

The 14th version of the International SOBRADPEC Congress and Translational Research Forum deals with the topic of translational research, with important emphasis on the themes involved, which are extremely opportune and timely. The response of the Brazilian academic community exceeded expectations to such an extent that Professor Saul Goldenberg decided to publish three supplements of Acta Cirurgica Brasileira covering a total of 38 full papers enrolled in the Congress. These studies originated from practically all regions of Brazil, with a predominance of the Southeast, Northeast and South, as shown in Figure 1. We should also point out the presence of participations from Canada and France. This geographic coverage clearly shows the stage of development of clinical, experimental and especially translational research in our country, with bilateral international ramifications. The success of this congress reflects the success of Brazilian experimental surgery which, in fact is inseparable from clinical and translational research. When dealing with medicine in general or with surgery in particular, with translational characteristics from bench to bed and vice versa, we can see the importance of the concepts of basic research in the daily work of surgeons. Indeed, regarding the questions and ideas existing in the mind of academic surgeons and the application of knowledge to the clinical-surgical environment, the surgeon relies on his research knowledge for clinical application.

To proliferate, not to proliferate or to die. The liver itself decides as needed

. The term hepatic regeneration, although commonly used, is biologically incorrect since the response induced by the resection of hepatic tissue is not truly regenerative. The resected lobes do not develop again. The restoration of hepatic mass occurs by compensatory cell hyperplasia in the remaining lobes, with a consequent increase in its dimensions