Comparison of Four Methods of RNA Extraction and cDNA Synthesis from The Venom of Peruvian Snakes of the Genus Bothrops of Clinical Importance.

RNA purification and cDNA synthesis represents the starting point for molecular analyses of snake venom proteins-enzymes. Usually, the sacrifice of snakes is necessary for venom gland extraction to identify protein-coding transcripts; however, the venom can be used as a source of transcripts. Although there are methods for obtaining RNA from venom, no comparative analysis has been conducted in the Bothrops genus. In the present study, we compared four commercial methods for RNA purification and cDNA synthesis from venom (liquid, lyophilized, or long-term storage) of four clinically relevant species of Peruvian Bothrops. Our results show that the TRIzol method presents the highest yield of RNA purified from venom (59 ± 11 ng/100 µL or 10 mg). The SuperScript First-Strand Synthesis System kit produced high amounts of cDNA (3.2 ± 1.2 ng cDNA/ng RNA), and the highest value was from combination with the Dynabeads mRNA DIRECT kit (4.8 ± 2.0 ng cDNA/ng RNA). The utility of cDNA was demonstrated with the amplification of six relevant toxins: thrombin-like enzymes, P-I and P-III metalloproteinases, acid and basic phospholipases A2, and disintegrins. To our knowledge, this is the first comparative study of RNA purification and cDNA synthesis methodologies from Bothrops genus venom.

Atroxlysin-III, A Metalloproteinase from the Venom of the Peruvian Pit Viper Snake Bothrops atrox (Jergón) Induces Glycoprotein VI Shedding and Impairs Platelet Function.

Atroxlysin-III (Atr-III) was purified from the venom of Bothrops atrox. This 56-kDa protein bears N-linked glycoconjugates and is a P-III hemorrhagic metalloproteinase. Its cDNA-deduced amino acid sequence reveals a multidomain structure including a proprotein, a metalloproteinase, a disintegrin-like and a cysteine-rich domain. Its identity with bothropasin and jararhagin from Bothrops jararaca is 97% and 95%, respectively. Its enzymatic activity is metal ion-dependent. The divalent cations, Mg2+ and Ca2+, enhance its activity, whereas excess Zn2+ inhibits it. Chemical modification of the Zn2+-complexing histidine residues within the active site by using diethylpyrocarbonate (DEPC) inactivates it. Atr-III degrades plasma fibronectin, type I-collagen, and mainly the α-chains of fibrinogen and fibrin. The von Willebrand factor (vWF) A1-domain, which harbors the binding site for GPIb, is not hydrolyzed. Platelets interact with collagen via receptors for collagen, glycoprotein VI (GPVI), and α2ß1 integrin. Neither the α2ß1 integrin nor its collagen-binding A-domain is fragmented by Atr-III. In contrast, Atr-III cleaves glycoprotein VI (GPVI) into a soluble ~55-kDa fragment (sGPVI). Thereby, it inhibits aggregation of platelets which had been stimulated by convulxin, a GPVI agonist. Selectively, Atr-III targets GPVI antagonistically and thus contributes to the antithrombotic effect of envenomation by Bothrops atrox.

Femoral hernia sac laparoscopy: a case report.

We present the case of a 64-year-old female with an incarcerated right femoral hernia, associated with a small bowel obstruction that was successfully treated with an open femoral hernia repair with plug. At the same time we performed a hernia sac laparoscopy to evaluate the viability of the previously reduced small bowel. The hernioscopy was performed with a 0° 5 mm scope with reliable evaluation of the peritoneal cavity. We confirm that hernioscopy is a safe and feasible procedure and provides useful information for the appropriate management of acute incarcerated femoral/inguinal hernias.

Bothrops atrox venom: Biochemical properties and cellular phenotypes of three highly toxic classes of toxins.

Snake venoms have a complex mixture of compounds that are conserved across species and act synergistically, triggering severe local and systemic effects. Identification of the toxin classes that are most damaging to cell homeostasis would be a powerful approach to focus on the main activities that underpin envenomation. Here, we focus on the venom of Bothrops atrox, snake responsible for most of the accidents in Amazon region of South America. We identified the key cytotoxic toxin fractions from B. atrox venom and mapped their biochemical properties, protein composition and cell damage. Five fractions were obtained by mass exclusion chromatography and contained either a single class of enzymatic activity (i.e., L-amino acid oxidases or Hyaluronidases) or different activities co-distributed in two or more protein fractions (e.g., Metalloproteinases, Serine Proteases, or Phospholipases A2). Only three protein fractions reduced cell viability of primary human cells. Strikingly, such activity is accompanied by disruption of cell attachment to substratum and to neighbouring cells. Such strong perturbation of morphological cell features indicates likely defects in tissue integrity in vivo. Mass spectrometry identified the main classes of toxins that contribute to these phenotypes. We provide here a strategy for the selection of key cytotoxic proteins for targeted investigation of their mechanism of action and potential synergism during snakebite envenomation. Our data highlights putative toxins (or combinations of) that may be the focus of future therapeutic interference.

Simultaneous identification of three clinically relevant peruvian pit vipers by multiplex loop-mediated isothermal amplification (mLAMP).

Previous knowledge about the taxonomic distribution of venomous snake species is very useful for epidemiological aspects of ophidism. Here, we sought to develop an assay for the differential identification of clinically relevant snakes in Peru: Bothrops atrox, Lachesis muta, and Crotalus durissus using a multiplex loop-mediated isothermal amplification (mLAMP) assay. For this, DNA was extracted from the shed snake skins and the mitochondrial genes Cytb, COI, and 12S rRNA were amplified and further sequenced, for the design of mLAMP reaction primers. For each snake species the forward and reverse primers, internal forward and reverse primers, and the loop primers were obtained, bearing the latter different fluorophores for product identification. Finally, the reaction was standardized in the presence of all primer sets, and an optimal amount of low molecular weight polyethyleneimine. The precipitated products were observed in a UV light transilluminator, finding a differential fluorescence according to the DNA used, with a detection limit to the naked eye in the range of 0.2-25 ng of DNA, within 30 min. This study is the first report on the use of mLAMP technology for the identification of venomous snakes.

Rhomb-I, a P-I metalloproteinase from Lachesis muta rhombeata venom degrades vessel extra cellular matrix components and impairs platelet aggregation.

Rhomb-I, a 23-kDa metalloproteinase was isolated from L. m. rhombeata venom. Its dimethylcasein proteolysis was abolished by metal chelators, and slightly enhanced by Ca2+ and Mg2+ ions, but inhibited by Co2+, Zn2+ and α2-macroglobulin. In aqueous solution, rhomb-I autoproteolyzed to a 20- and 11-kDa fragments at 37 °C. The amino acid sequence showed high homology with other snake venom metalloproteinases. Rhomb-I causes hemorrhage that may be ascribed to hydrolysis of essential basement membrane, extracellular matrix and plasma proteins. It preferentially cleaves the α-chains of fibrin (ogen). Rhomb-I inhibited convulxin- and von Willebrand factor (vWF)-induced aggregation on human platelets without significant effect on collagen-stimulated aggregation or other effectors. It digests vWF into a low-molecular-mass multimers of vWF and a rvWF-A1 domain to a 27-kDa fragment as revealed by western blotting with mouse anti-rvWF A1-domain IgG. Incubation of platelets with rhomb-I resulted in adhesion to and cleavage of platelet receptors glycoprotein (GP)Ibα and GPVI to release a 55-kDa soluble form. Both membrane glycoproteins GPIbα that binds vWF, together with GPVI which binds collagen, play a key role in mediating platelet adhesion/activation and can initiate (patho)physiological thrombus formation. Conclusions: rhomb-I is implicated in the pathophysiology of Lachesis envenoming by disrupting vasculature, hemostasis and platelet aggregation through impairing vWF-GPIb axis and blocking GPVI-collagen binding.

Pictolysin-III, a Hemorrhagic Type-III Metalloproteinase Isolated from Bothrops pictus (Serpentes: Viperidae) Venom, Reduces Mitochondrial Respiration and Induces Cytokine Secretion in Epithelial and Stromal Cell Lines.

From the venom of the Bothrops pictus snake, an endemic species from Peru, we recently have described toxins that inhibited platelet aggregation and cancer cell migration. In this work, we characterize a novel P-III class snake venom metalloproteinase, called pictolysin-III (Pic-III). It is a 62 kDa proteinase that hydrolyzes dimethyl casein, azocasein, gelatin, fibrinogen, and fibrin. The cations Mg2+ and Ca2+ enhanced its enzymatic activity, whereas Zn2+ inhibited it. In addition, EDTA and marimastat were also effective inhibitors. The amino acid sequence deduced from cDNA shows a multidomain structure that includes a proprotein, metalloproteinase, disintegrin-like, and cysteine-rich domains. Additionally, Pic-III reduces the convulxin- and thrombin-stimulated platelet aggregation and in vivo, it has hemorrhagic activity (DHM = 0.3 µg). In epithelial cell lines (MDA-MB-231 and Caco-2) and RMF-621 fibroblast, it triggers morphological changes that are accompanied by a decrease in mitochondrial respiration, glycolysis, and ATP levels, and an increase in NAD(P)H, mitochondrial ROS, and cytokine secretion. Moreover, Pic-III sensitizes to the cytotoxic BH3 mimetic drug ABT-199 (Venetoclax) in MDA-MB-231 cells. To our knowledge, Pic-III is the first SVMP reported with action on mitochondrial bioenergetics and may offer novel opportunities for promising lead compounds that inhibit platelet aggregation or ECM-cancer-cell interactions.

Elective laparoscopic versus open colectomy for diverticulosis: an analysis of ACS-NSQIP database.

BACKGROUND: The benefits of laparoscopic (LC) versus open (OC) colectomy for symptomatic colonic diverticulosis as an elective operation remain unclear. METHODS: Using the American College of Surgeons-National Surgical Quality Improvement Project (ACS-NSQIP) participant-user file, patients were identified who underwent elective colon resection for symptomatic colonic diverticulosis, between 2005 and 2008. Demographic, clinical, intraoperative variables, and 30-day morbidity and mortality were collected. Logistic regression analysis was performed to determine the association between the surgical approach (LC vs. OC) and risk-adjusted overall mortality, overall morbidity, serious morbidity, and wound complications. RESULTS: A total of 7,629 patients were identified who underwent colon resection for symptomatic diverticulosis. They were subdivided into two groups: OC (3,870 (50.7%)) and LC (3,759 (49.3%)). Patients who underwent OC were significantly older (59.0 vs. 55.7 years, P < 0.0001) with more comorbidities compared with those who underwent LC. After risk-adjusted analysis, it was noted that the patients treated with LC were significantly less likely to experience overall morbidity (11.9% vs. 23.2%), serious morbidity (4.6% vs. 10.9%), and wound complications (9.1% vs. 17.5%), but not mortality (0.3% vs. 0.8%). Operative duration was significantly longer with LC (176.64 vs. 166.70 min, P < 0.0001), but the length of stay was significantly shorter (4.77 vs. 7.68 days, P < 0.0001). Using logistic regression analysis, patients with history of peripheral vascular disease, percutaneous coronary interventions, current steroid use, and hypertension requiring medication were at an increased risk of morbidity and mortality at 30 days. Patients with history of chronic obstructive pulmonary disease and smoking experienced more wound complications at 30 days. CONCLUSIONS: In the elective setting for symptomatic diverticulosis, LC seems to be associated with lower 30-day morbidity and complication rates compared with OC.

Molecular diagnosis of amoebiasis.

Amoebiasis is an intestinal parasitosis caused by the protozoan Entamoeba histolytica that represents the third leading cause of mortality due to parasitosis. It is a prevalent disease in tropical climate regions with poor or absent sanitary services. Microscopy and antigen detection techniques are routinely used to diagnose amoebiasis because of their low cost and ease of application. However, these techniques do not differentiate E. histolytica infections and other potentially pathogenic species such as Entamoeba moshkovskii or Entamoeba bangladeshi. Therefore, in the last decades, molecular tests that allow correct identification of the causal agent of amoebiasis and the establishment of the prevalence of the infecting species have been developed. Techniques based on nucleic acids, such as conventional, multiplex, or real-time polymerase chain reaction (PCR), are being seriously considered in clinical laboratories, because they detect the etiologic agent directly from the sample without the need for previous prolonged culture, thus reducing diagnostic time. Also, the nested PCR test and the sequencing of ribosomal markers have allowed the identification of new parasitic species in humans, such as E. moshkovskii and E. bangladeshi, and an improved characterization of the known infecting species. The application of multiplex platforms allows the simultaneous identification of infecting species, increasing the sensitivity and specificity of these techniques. Therefore, the molecular diagnosis of amoebiasis is projected as an innovative tool in the fight against this parasitosis.

La amebiasis es una parasitosis intestinal causada por el protozoario Entamoeba histolytica y representa la tercera causa de mortalidad por parasitosis. Es una enfermedad prevalente en regiones de clima tropical con deficientes o nulos servicios sanitarios. Las técnicas de microscopía y detección de antígenos se emplean sistemáticamente para el diagnóstico de la amebiasis por su bajo costo y fácil aplicación. Sin embargo, no permiten diferenciar entre infecciones por E. histolytica y otras especies de potencial patogenicidad como Entamoeba moshkovskii o Entamoeba bangladeshi. Ante ello, en las últimas décadas se han desarrollado pruebas moleculares que permiten una correcta identificación del agente causal de la amebiasis y el establecimiento de la prevalencia de la especie infectante. Las técnicas basadas en ácidos nucleicos, como la reacción en cadena de la polimerasa (PCR) convencional, múltiple o en tiempo real, están siendo seriamente consideradas en los laboratorios clínicos, porque detectan al agente etiológico de manera directa en la muestra sin necesidad de cultivo prolongado previo, disminuyendo de esta forma el tiempo del diagnóstico. Asimismo, la PCR anidada sumada a la secuenciación de marcadores ribosomales ha permitido la identificación de nuevas especies parasitarias, como E. moshkovskii y E. bangladeshi en humanos, y una mejor caracterización de las especies infectantes ya conocidas. La aplicación de las plataformas multiplex permite la identificación simultánea de especies infectantes, aumentando la sensibilidad y la especificidad de estas técnicas. Por esto, el diagnóstico molecular de la amebiasis se proyecta como una verdadera herramienta innovadora en la lucha contra las parasitosis.

An Emergent Role for Mitochondrial Bioenergetics in the Action of Snake Venom Toxins on Cancer Cells.

Beyond the role of mitochondria in apoptosis initiation/execution, some mitochondrial adaptations support the metastasis and chemoresistance of cancer cells. This highlights mitochondria as a promising target for new anticancer strategies. Emergent evidence suggests that some snake venom toxins, both proteins with enzymatic and non-enzymatic activities, act on the mitochondrial metabolism of cancer cells, exhibiting unique and novel mechanisms that are not yet fully understood. Currently, six toxin classes (L-amino acid oxidases, thrombin-like enzymes, secreted phospholipases A2, three-finger toxins, cysteine-rich secreted proteins, and snake C-type lectin) that alter the mitochondrial bioenergetics have been described. These toxins act through Complex IV activity inhibition, OXPHOS uncoupling, ROS-mediated permeabilization of inner mitochondrial membrane (IMM), IMM reorganization by cardiolipin interaction, and mitochondrial fragmentation with selective migrastatic and cytotoxic effects on cancer cells. Notably, selective internalization and direct action of snake venom toxins on tumor mitochondria can be mediated by cell surface proteins overexpressed in cancer cells (e.g. nucleolin and heparan sulfate proteoglycans) or facilitated by the elevated Δψm of cancer cells compared to that non-tumor cells. In this latter case, selective mitochondrial accumulation, in a Δψm-dependent manner, of compounds linked to cationic snake peptides may be explored as a new anti-cancer drug delivery system. This review analyzes the effect of snake venom toxins on mitochondrial bioenergetics of cancer cells, whose mechanisms of action may offer the opportunity to develop new anticancer drugs based on toxin scaffolds.

findMySequence: a neural-network-based approach for identification of unknown proteins in X-ray crystallography and cryo-EM.

Although experimental protein-structure determination usually targets known proteins, chains of unknown sequence are often encountered. They can be purified from natural sources, appear as an unexpected fragment of a well characterized protein or appear as a contaminant. Regardless of the source of the problem, the unknown protein always requires characterization. Here, an automated pipeline is presented for the identification of protein sequences from cryo-EM reconstructions and crystallographic data. The method's application to characterize the crystal structure of an unknown protein purified from a snake venom is presented. It is also shown that the approach can be successfully applied to the identification of protein sequences and validation of sequence assignments in cryo-EM protein structures.

Functional, immunological characterization, and anticancer activity of BaMtx: A new Lys49- PLA2 homologue isolated from the venom of Peruvian Bothrops atrox snake (Serpentes: Viperidae).

Bothorps atrox is responsible for most of the ophidism cases in Perú. As part of the envenoming, myotoxicity is one of the most recurrent and destructive effects. In this study, a myotoxin, named BaMtx, was purified from B. atrox venom to elucidate its biological, immunological, and molecular characteristics. BaMtx was purified using CM-Sephadex-C-25 ion-exchange resin and SDS-PAGE analysis showed a unique protein band of 13 kDa or 24 kDa under reducing or non-reducing conditions, respectively. cDNA sequence codified a 122-aa mature protein with high homology with other Lys49-PLA2s; modeled structure showed a N-terminal helix, a ß-wing region, and a C-terminal random coil. This protein has a poor phospholipase A2 enzymatic activity. BaMtx has myotoxic (DMM = 12.30 ± 0.95 µg) and edema-forming (DEM = 26.00 ± 1.15 µg) activities. Rabbit immunization with purified enzyme produced anti-BaMtx antibodies that reduced 50.28 ± 10.15% of myotoxic activity and showed significant cross-reactivity against B. brazili and B pictus venoms. On the other hand, BaMtx exhibits mild anti-proliferative and anti-migratory effects on breast cancer cells, affecting the ROS and NADH levels, which may reduce mitochondrial respiration. These results contribute to the understanding of B. atrox Lys49-PLA2 effects and establish the anticancer potential de BaMtx.

How reliable is laparoscopic colorectal surgery compared with laparotomy for octogenarians?

BACKGROUND: Due to the current increased longevity in the elderly population and the increased size of that population, major abdominal intervention is more frequently performed among octogenarians. This study aimed to compare the surgical and postoperative outcomes of laparoscopic colorectal resections with those of open surgery in the octogenarian population. METHODS: Retrospective analysis based on a prospectively maintained database of octogenarians who underwent laparoscopic or open elective colorectal resections from 2001 to 2008 was performed. Diagnosis, comorbidities, operative data, and early postoperative complications are analyzed in this report. RESULTS: Colon resection was performed for 199 octogenarians, using laparotomy for 116 patients (group 1) and laparoscopic surgery for 83 patients (group 2). The mean age was 84.3 years for the laparotomy patients and 84.7 years for the laparoscopic patients. The American Society of Anesthesiology (ASA) scores was comparable between groups 1 and 2. Colorectal adenoma was the most common indication for surgery in both groups: for 77.6% of the group 1 patients and 54.2% of the group 2 patients. Right colectomy was the most frequently performed operation in group 2: for 57.8% of the group 2 patients and 31% of the group 1 patients (p = 0.0003). Open resections had a higher mean blood loss in both group 1 (286 ml) and group 2 (152 ml) (p = 0.0002), and more patients required intraoperative transfusions (p = 0.005) despite similar operative times. The conversion rate in the laparoscopic group was 25.3%. The patients in the laparoscopic group had less morbidity, both overall and clinically, than the open group (p < 0.05). The median hospital stay was 8 days in group 1 and 6 days in group 2 (p = 0.0065). The rate of major surgical complications was similar in the two groups of patients: 6% in group 1 and 4.8% in group 2. The reoperation rate was 2.6% in group 1 and 3.6% in group 2 (p > 0.05). The mortality rate was 3.4% in group 1 and 2.4% in group 2. CONCLUSIONS: Laparoscopic colorectal resection was effective and safe for octogenarians, with less blood loss and faster postoperative recovery. The morbidity rate is lower than for traditional laparotomy.

Does the radiofrequency procedure for fecal incontinence improve quality of life and incontinence at 1-year follow-up?

PURPOSE: Fecal incontinence is a socially isolating disease that causes physical and psychologic distress. Radiofrequency delivered to the anal canal is a surgical modality for fecal incontinence that has been noted to be safe and potentially effective. The aim of this study was to evaluate improvement in fecal incontinence and quality of life after the radiofrequency procedure at 1-year follow-up. METHODS: After institutional review board approval, patients with fecal incontinence for at least 3 months were prospectively recruited between March 2003 and June 2004. Patients enrolled in the study underwent the Secca procedure. The Cleveland Clinic Florida Fecal Incontinence Score and the Fecal Incontinence Quality of Life Questionnaire were completed at the first visit and then at 12-month follow-up. Wilcoxon signed rank test was used to analyze the difference between baseline and follow-up. RESULTS: A total of 24 patients (23 females) were enrolled in the study, and 16 were available at the 12-month follow-up visit. The main causes of fecal incontinence were either idiopathic or included obstetric injury, aging, and trauma from previous anorectal surgeries. The mean operative time was 45.5 +/- 8.3 minutes, and the mean number of radiofrequency lesions in the anal canal was 65.5 +/- 13.8. There were 3 self-limited episodes of postoperative bleeding and 1 instance of constipation that was resolved with laxatives. There were no delayed complications. The mean Cleveland Clinic Florida Fecal Incontinence Score improved from a mean of 15.6 (+/- 3.2) at baseline to 12.9 (+/- 4.6) at 12 months (P = .035). The mean Fecal Incontinence Quality of Life Questionnaire score improved in all subsets except for the depression subscore. CONCLUSION: Radiofrequency is a safe, minimally invasive tool for treating patients with fecal incontinence. Improvement in fecal incontinence and quality of life was maintained at 12 months without delayed morbidity. The actual significance of this improvement is yet to be determined.

Fibrinogen-clotting enzyme, pictobin, from Bothrops pictus snake venom. Structural and functional characterization.

A thrombin-like enzyme, pictobin, was purified from Bothrops pictus snake venom. It is a 41-kDa monomeric glycoprotein as showed by mass spectrometry and contains approx. 45% carbohydrate by mass which could be removed with N-glycosidase. Pictobin coagulates plasma and fibrinogen, releasing fibrinopeptide A and induces the formation of a friable/porous fibrin network as visualized by SEM. The enzyme promoted platelet aggregation in human PRP and defibrination in mouse model and showed catalytic activity on chromogenic substrates S-2266, S-2366, S-2160 and S-2238. Pictobin interacts with the plasma inhibitor α2-macroglobulin, which blocks its interaction with fibrinogen but not with the small substrate BApNA. Heparin does not affect its enzymatic activity. Pictobin cross reacted with polyvalent bothropic antivenom, and its deglycosylated form reduced its catalytic action and antivenom reaction. In breast and lung cancer cells, pictobin inhibits the fibronectin-stimulated migration. Moreover, it produces strong NADH oxidation, mitochondrial depolarization, ATP decrease and fragmentation of mitochondrial network. These results suggest by first time that a snake venom serinprotease produces mitochondrial dysfunction by affecting mitochondrial dynamics and bioenergetics. Structural model of pictobin reveals a conserved chymotrypsin fold ß/ß hydrolase. These data indicate that pictobin has therapeutic potential in the treatment of cardiovascular disorders and metastatic disease.

Esophageal perforation after gastric balloon extraction.

We report a case of a 59-year-old female with esophageal perforation following endoscopic removal of an intragastric balloon. To our knowledge, this is the first case of esophageal perforation associated with intragastric balloon extraction reported in the English literature.

Molecular Sexing of the White-Winged Guan (Penelope albipennis) and Other Wild Birds of the North of Peru.

The use of accurate and reliable techniques for sex determination of wild birds is of special importance in captive breeding programs, especially in birds with monogamous, aggressive behavior, with absence of copulation, and with a low hatching rate. Using PCR, we evaluated the relative efficacy of primers HPF/HPR and CHD1Wr/NP/CHD1Zr in the amplification of the chromo-helicase-DNA binding 1 (CHD1) gene for sex determination in Penelope albipennis and 8 other species of cracids, 4 species of falconids, 4 species of accipitrids, and 3 species of psittacines. Primer effectiveness was compared using previously sexed bird samples. The HPF/HPR primer set was found to demonstrate a better performance and reliability. Therefore, these primers should be used to determine the sex of juvenile birds to avoid or minimize incompatibilities during the selection of potential breeding pairs.

Biochemical and molecular characterization of the hyaluronidase from Bothrops atrox Peruvian snake venom.

Snake venoms are a rich source of enzymes such as metalloproteinases, serine proteinases phospholipases A2 and myotoxins, that have been well characterized structurally and functionally. However, hyaluronidases (E.C.3.2.1.35) have not been studied extensively. In this study, we describe the biochemical and molecular features of a hyaluronidase (Hyal-Ba) isolated from the venom of the Peruvian snake Bothrops atrox. Hyal-Ba was purified by a combination of ion-exchange and gel filtration chromatography. Purified Hyal-Ba is a 69-kDa (SDS-PAGE) monomeric glycoprotein with an N-terminal amino acid sequence sharing high identity with homologous snake venom hyaluronidases. Detected associated carbohydrates were hexoses (16.38%), hexosamines (2.7%) and sialic acid (0.69%). Hyal-Ba selectively hydrolyzed only hyaluronic acid (HA; specific activity = 437.5 U/mg) but it did not hydrolyze chondroitin sulfate or heparin. The optimal pH and temperature for maximum activity were 6.0 and 40 °C, respectively, and its Km was 0.31 µM. Its activity was inhibited by EDTA, iodoacetate, 2-mercaptoethanol, TLCK and dexamethasone. Na+ and K+ (0.2 M) positively affect hyaluronidase activity; while Mg2+, Br2+, Ba2+, Cu2+, Zn2+, and Cd2+ reduced catalytic activity. Hyal-Ba potentiates the hemorrhagic and hemolytic activity of whole venom, but decreased subplantar edema caused by an l-amino acid oxidase (LAAO). The Hyal-Ba cDNA sequence (2020 bp) encodes 449 amino acid residues, including the catalytic site residues (Glu135, Asp133, Tyr206, Tyr253 and Trp328) and three functional motifs for N-linked glycosylation, which are conserved with other snake hyaluronidases. Spatial modeling of Hyal-Ba displayed a TIM-Barrel (α/ß) fold and an EGF-like domain in the C-terminal portion. The phylogenetic analysis of Hyal-Ba with other homologous Hyals showed the monophyly of viperids. Further, Hyal-Ba studies may extend our knowledge of B. atrox toxinology and provides insight to improve the neutralizing strategies of therapeutic antivenoms.

L-amino acid oxidase from Bothrops atrox snake venom triggers autophagy, apoptosis and necrosis in normal human keratinocytes.

Snake venom L-amino acid oxidases (LAAOs) are flavoproteins, which perform diverse biological activities in the victim such as edema, myotoxicity and cytotoxicity, contributing to the development of clinical symptoms of envenomation. LAAO cytotoxicity has been described, but the temporal cascade of events leading to cell death has not been explored so far. This study evaluates the involvement of LAAO in dermonecrosis in mice and its cytotoxic effects in normal human keratinocytes, the major cell type in the epidermis, a tissue that undergoes extensive necrosis at the snakebite site. Pharmacological inhibition by the antioxidant NAC (N-acetyl cysteine) prevented B. atrox venom-induced necrosis. Consistent with the potential role of oxidative stress in wounding, treatment with purified LAAO decreased keratinocyte viability with an Effective Concentration (EC50) of 5.1 µg/mL. Cytotoxicity caused by LAAO was mediated by H2O2 and treated cells underwent autophagy, followed by apoptosis and necrosis. LAAO induced morphological alterations that precede cell death. Our results show the chronological events leading to cell death and the temporal resolution from autophagy, apoptosis and necrosis as distinct mechanisms triggered by LAAO. Fluorescently-labelled LAAO was efficiently and rapidly internalized by keratinocytes, suggesting that catalysis of intracellular substrates may contribute to LAAO toxicity. A better understanding of LAAO cytotoxicity and its mechanism of action will help to identify potential therapeutic strategies to ameliorate localized snake envenomation symptoms.

Gracilis muscle interposition for the treatment of rectourethral, rectovaginal, and pouch-vaginal fistulas: results in 53 patients.

BACKGROUND: The aim of this study was to review our experience with gracilis muscle interposition for complex perineal fistulas. MATERIAL AND METHODS: A retrospective review of all patients who underwent repair of perineal fistula using the gracilis muscle between 1995 and 2007 was undertaken. Patients were divided into 2 groups according to the fistula type by gender: females (rectovaginal and pouch-vaginal) and males (rectourethral). RESULTS: Gracilis interposition was performed in 53 patients. Seventeen women underwent 19 gracilis interpositions for 15 rectovaginal and 2 pouch-vaginal fistulas; 76% had a mean of (1-4) (mean of 2) prior failed attempt at repair. Eight patients experienced at least one postoperative complication. Two women required a second gracilis interposition. Thirty-three percent of the Crohn's disease-associated fistulas successfully healed; 75% without Crohn's successfully healed.Thirty-six males underwent gracilis interposition for rectourethral fistulas, mainly due to prostate cancer treatment; 13 (36%) had a mean of 1.5 (range 1-3) failed prior repairs. Seventeen patients experienced postoperative complications. The initial success rate in men with rectourethral fistulas was 78%. After successful second procedures in 8 patients, the overall clinical healing rate was 97%. CONCLUSION: The gracilis muscle transposition is a safe and effective method of treating complex perianal fistulas.