Adrian Dragu

Gene Expression of Brain Natriuretic Peptide in Isolated Atrial and Ventricular Human Myocardium Influence of Angiotensin II and Diastolic Fiber Length

Background—We studied the effects of angiotensin II (Ang II) and diastolic overstretch on the induction of cardiac growth in isometrically contracting muscle preparations from human right atria and left ventricles. We used the gene expression of brain natriuretic peptide (BNP) as a molecular marker of cardiac hypertrophy. Methods and Results—Northern blot analysis was performed in human atrial muscle preparations, which were either incubated in 10−6 mol/L Ang II for 45 minutes or diastolically stretched to 120% of optimum muscle length. Similar experiments were performed with human left ventricular muscle preparations. Results were as follows: (1) BNP gene expression increased in human atrial myocardium 4-fold when stimulated by Ang II (n=7, P <0.001). (2) Diastolic overstretch increased BNP expression in a time-dependent manner. The linear regression equations for the BNP/GAPDH ratio as a function of time (hours) were y=1.21+0.62x (P <0.001) for overstretched preparations and y=1.07−0.01x (P =NS) for atrial preparations kept at physiological muscle length. (3) In left ventricular human muscle preparations, diastolic overstretch and Ang II increased BNP gene expression as well. (4) In addition, the Ang II subtype 1 receptor blocker losartan was able to block the effects of Ang II and diastolic overstretch. Conclusions—Cardiac hypertrophy can be induced in isolated human atrial and left ventricular intact myocardium by Ang II and diastolic overstretch but not by isometric afterload. The fact that the induction of cardiac growth is inhibited by the blockade of Ang II subtype 1 receptors is of scientific and clinical importance.

Ischemia triggers BNP expression in the human myocardium independent from mechanical stress

BACKGROUND It is unknown whether the increased B-type natriuretic peptide (BNP) values found in ischemic heart disease are triggered directly by ischemia or whether they are caused indirectly by ischemia through diastolic contractures or regional wall motion abnormalities. Therefore, we investigated the BNP expression in isolated human muscle strips under conditions of ischemia with and without mechanical stress. METHODS Muscle strips (n=90) were isolated from human right atria (n=46). Contractures were induced by oxygen and glucose withdrawal. In 18 muscle strips contractures were prevented by means of butanedione monoxime (BDM). Sarcomere lengths were measured by electron microscopy (n=12). The gene expression and protein amount of BNP were determined and compared to control muscle strips contracting under physiological conditions. RESULTS Hypoxia significantly decreased systolic force and induced diastolic contractures. This mechanical stress could be prevented in the group treated with BDM as evidenced by electron microscopy. Ischemia significantly increased BNP expression in both groups as evidenced by Northern blot analysis and immunohistochemistry. This increase was independent from mechanical stress. CONCLUSION Our results indicate that ischemia is a potent mechanism for the expression of BNP. The increase in BNP expression under ischemic conditions is independent from concomitant mechanical alterations.

Immunohistochemical evaluation after ex vivo perfusion of rectus abdominis muscle flaps in a porcine model.

Background: The purpose of this study was to investigate whether and how the extracorporal perfusion of muscle flaps with a miniaturized perfusion system could change the expression of the proapoptotic protein caspase 3 and of the ischemia-sensitive protein hypoxia-inducible factor (HIF)-1&agr; as a first step toward the development of a clinically reliable tool for circumventing ischemia problems in free muscle flap transfer. Methods: In this study, 25 porcine rectus abdominis muscles were used and assigned to five different groups. In the baseline group (group I), the muscle flap remained in situ; in groups II and III, the muscle flap was harvested and remained ex vivo without or with subsequent single-shot heparinized flush; and in groups IV and V, the flaps were perfused with either heparinized autologous whole blood or crystalloid fluid (Jonosteril), using a miniaturized perfusion system without Exogen oxygenation. Muscle samples were taken for immunohistochemical evaluation. The proportion of positive cells for HIF-1&agr; and caspase 3 was compared for each group (groups II through V) to the baseline group (group I). Results: The expression of HIF-1&agr; and caspase 3 was increased in both groups without perfusion and was low during in vivo perfusion and extracorporal perfusion with crystalloid fluid. Heparinized autologous whole blood perfusion shows no protective effect, in contrast to the crystalloid fluid. Conclusions: The data of this study indicate that the extracorporal perfusion of muscle flaps with crystalloid fluid is a possible protective strategy against ischemia. Autologous heparinized whole blood seems to have no additional protective effect in a pure perfusion setting without oxygenation.

Expression of HIF-1α in ischemia and reperfusion in human microsurgical free muscle tissue transfer.

Background: The aim of this study was to analyze the expression of hypoxia-inducible factor (HIF)-1&agr; during ischemia and after reperfusion in muscle tissue in the context of microsurgical free muscle tissue transfer. Methods: Ten patients with soft-tissue defects needing coverage with microsurgical free muscle flaps were included in this study. In all patients, the muscle samples were taken from free myocutaneous flaps. The first sample was taken before induction of ischemia in normoxia, another one was taken after 72 ± 11 minutes of ischemia, and the last one was taken 77 ± 22 minutes after reperfusion. The samples were analyzed using DNA microarray, real-time polymerase chain reaction, and immunohistochemistry. Results: DNA microarray, real-time polymerase chain reaction, and immunohistochemistry did not provide evidence of differential expression of HIF-1&agr; comparing ischemia and reperfusion to normoxia. However, DNA microarray showed an up-regulation of activating transcription factor-3 during ischemia and spermine N1-acetyltransferase-1 during ischemia and reperfusion. Conclusions: This study shows that ischemia and reperfusion induce alterations on the gene expression level in human muscle free flaps. Data from this study indicate that the expression of HIF-1&agr; might not be affected but that other putative pathways of ischemic regulation might be of great interest. Finally, these findings correspond with the surgeons clinical experience that the accepted times of ischemia, generally up to 90 minutes, are not sufficient to induce pathophysiologic processes, which can ultimately lead to flap loss.

Assessing viability of extracorporeal preserved muscle transplants using external field stimulation: a novel tool to improve methods prolonging bridge-to-transplantation time

Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation. Perfusion protocols have been established for a variety of applications and proven to be superior to procedures used in clinical routine. Extracorporeal perfusion of muscle tissue though cumbersome is highly desirable since it is highly susceptible to ischemia-related damage. To show the efficacy of different perfusion protocols external field stimulation can be used to immediately visualize improvement or deterioration of the tissue during active and running perfusion protocols. This method has been used to show the superiority of extracorporeal perfusion using porcine rectus abdominis muscles perfused with heparinized saline solution. Perfused muscles showed statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. The combination of extracorporeal perfusion and external field stimulation may improve organ conservation research.

Evaluation of Intra-Operative Abdominal Wall Perfusion in Post-Bariatric Abdominal Dermolipectomy

Objective: Abdominal dermolipectomy after massive weight loss has become a standard procedure. However the complication rates such as wound necrosis or secondary healing complications are still high. In this context ischaemia or inadequate micro-perfusion are known as triggers of wound healing complications. Little is known about the regional perfusion patterns before and after post-bariatric abdominal dermolipectomy. This study focuses on assessment of intraoperative micro-perfusion patterns of the abdominal tissue. Methods: The perfusion of the abdominal wall flap was monitored intra-operatively in 17 patients with an average BMI of 29.2 ± 3.7 kg/m2 after bariatric surgery. All patients underwent abdominal post-bariatric dermolipectomy after massive weight loss while applying the non-invasive O2C laser-spectrophotometer. The micro-perfusion parameters oxygen saturation (SO2), relative haemoglobin content (rHB) and relative blood flow (BF) were intra-operatively measured. Results: The results of this study show that the part of the abdominal fat typically resected during dermolipectomy has the lowest SO2 before surgery. Furthermore, the results demonstrate that previously well oxygenated parts in the median line of the abdominal fat undergo a significant decrease in oxygen saturation upon mobilisation and subsequent suturing, while the caudal wound edges show an increase of micro-perfusion parameters. Conclusion: Data show that micro-perfusion is worst in the median line of the cranial wound edge and is significantly altered after mobilisation. In addition an intra-operative increase of micro-perfusion in the caudal part of the wound edge, especially in the mons pubis area, can be measured.

The transpelvic vertical rectus abdominis flap: one interdisciplinary approach to reduce postoperative complications after surgery for rectal cancer.

To the editor: W e want to congratulate the authors Paun et al1 for their very interesting recently published article.1 We read with great interest their systematic review determining postoperative complication rates after radical surgery for rectal cancer including abdominal perineal resection and anterior resection. The presented work clearly represents a reliable benchmark for complication rates seen after radical surgery for rectal cancer.2,3 On the basis of this new data, interdisciplinary approaches such as safe and tension-free closure of perineal defects with transpelvic vertical rectus abdominis flaps (VRAM) may show that postoperative complication rates can be reduced.4 The VRAM flap is raised with a skin island, which is usually up to 15 cm in length and between 5 and 7 cm in width, depending on the size of the sacral/perineal defect or the vaginal defect. The position of the skin island should be positioned from a position around the umbilicus and centered over the most frequent skin perforator vessels, which are located in this area. The skin paddle should extend as much cranially toward the costal margin as possible to provide enough tissue to loosely fit into the perineal defect without creating tension to the vascular pedicle. The skin paddle of the elevated rectus abdominis muscle is supplied by the vascular pedicle of the deep inferior epigastric artery and vein. The superior epigastric artery and vein are carefully ligated to prevent postoperative bleeding. A minimal part of the anterior rectus

Tc-99m Sestamibi Spect/ct as a New Tool for Monitoring Perfusion and Viability of Buried Perforator Based Free Flaps in Breast Reconstruction After Breast Cancer

Abstract:We report a case of a 53-year-old woman with ductal carcinoma in situ of the right breast. Skin-sparing mastectomy and single-stage reconstruction of the right breast with a “buried” free deep inferior epigastric perforator flap was performed. Classic clinical monitoring was not possible du

Nerve fiber staining investigations in traumatic and degenerative disc lesions of the wrist.

PURPOSE Traumatic and degenerative disc lesions cause ulnar-sided wrist pain. To date, anatomical investigations of cadaver triangular fibrocartilage discs examining the innervation of the triangular fibrocartilage complex have found no evidence of nerve fibers in the healthy disc. In this study, we immunohistologically investigated biopsies from patients with either central traumatic or degenerative disc lesions, to determine the existence of nerve fibers. We hypothesized that an ingrowth of nerve fibers causes ulnar-sided wrist pain associated with traumatic and degenerative disc lesions. METHODS We included 32 patients with a traumatic Palmer 1A lesion and 17 patients with a degenerative Palmer 2C lesion in the study. We obtained a biopsy of each patient and stained the specimen with protein gene product 9.5 for nerve fiber detection. RESULTS There were no nerve fibers in either traumatic or degenerative disc lesions. In addition, the marginal areas of the biopsies showed no evidence of nerve fibers. CONCLUSIONS Traumatic and degenerative disc lesions show no ingrowth of nerve fibers.

Efficacy of a Gel Containing Polihexanide and Betaine in Deep Partial and Full Thickness Burns Requiring Split-thickness Skin Grafts: A Noncomparative Clinical Study

Despite overall advances in burn therapy, wound infection remains one of the leading causes of morbidity and mortality in patients with severe burn injuries. This prospective, multicenter, noncomparative clinical trial was conducted to assess the efficacy and safety of Prontosan® Wound Gel X (PWX), a gel containing polihexanide and betaine, for moistening and cleansing in deep tissue burn wounds requiring split-thickness skin grafting. Patients with deep partial or full thickness burn wounds requiring split-thickness skin grafting were treated with the gel to evaluate its tolerability and safety as well as graft take and the healing of the skin graft. Target wounds were assessed clinically and by using a photo-planimetric analyzing software for re-epithelialization. From 04/2012 to 05/2015, burn patients from three burn centers in Germany were screened for the study, of which 51 patients met the inclusion criteria. Predominantly deep partial thickness burn wounds were found (88.2 %). Except for one graft failure, all patients reached complete re-epithelialization after one (n = 14), two (n = 31), or three (n = 5) administrations of the gel. The median time to complete graft take was 7 days and was below the average healing time reported in comparable studies. No wound infection or erythema occurred. This is the first study to document the outcomes of deep partial and full thickness burns treated with PWX for moistening and cleansing. The gel was shown to be efficacious, safe, and well tolerated for use in burn wounds requiring split-thickness skin grafts.