Hemogasometria arterial pré e pós-rinoplastia em cães braquicefálicos portadores de estenose de narina / Arterial hemogasometry pre and post rhinoplasty in brachyphalic dogs with nostril stenosis

Vinte e seis cães braquicefálicos portadores de estenose de narina, 22 machos e quatro fêmeas, foram submetidos à rinoplastia bilateral. Dezesseis cães eram Buldogues Franceses; dois, Buldogues Ingleses; seis, Pugs; e dois, Shih Tzus, com idade variando de seis meses a seis anos. Foram efetuadas coletas de sangue arterial para análises hemogasométricas no pré-operatório e 30 dias após a cirurgia. Para cada avaliação, foi obtida uma amostra de 0,5mL de sangue coletado da artéria femoral, em seringa plástica heparinizada. Em seguida, procedeu-se à avaliação hemogasométrica em analisador de gases sanguíneos (I-stat-Abbot®). Os resultados da hemogasometria pré e pós-rinoplastia mostraram uma redução nos valores médios de pCO2, TCO2 , HCO3- e BEecf, hematócrito e hemoglobina, e aumento de pH, pO2 e SO2, indicando melhora na condição ventilatória dos animais após a correção cirúrgica da estenose de narina. Isso posto, conclui-se que a hemogasometria arterial é um exame importante no diagnóstico da síndrome respiratória dos cães braquicefálicos, e extremamente útil no acompanhamento da resposta do paciente ao tratamento. A rinoplastia mostrou-se eficaz no tratamento da síndrome respiratória, promovendo melhora nos parâmetros hemogasométricos que indicam acidose respiratória secundária à obstrução das vias aéreas, comum nas raças braquicefálicas.(AU)

Twenty-six brachycephalic dogs with nostril stenosis, 22 males and four females, underwent bilateral rhinoplasty. Sixteen dogs were French Bulldogs; two, English Bulldogs; Six, Pugs; and two, Shih tzus, ranging in age from six months to six years. Blood samples were collected for hemogasometric analysis in the preoperative period and 30 days after surgery. For each evaluation, a 0.5ml sample of blood collected from the femoral artery was obtained in a heparinized plastic syringe. Hemogasometric evaluation was then performed on a blood gas analyzer (I-stat-Abbot®). The results of hemogasometry before and after rhinoplasty showed a reduction in the mean values of pCO2, TCO2, HCO3- and BEecf, hematocrit and hemoglobin, and an increase in pH, pO2 and SO2, indicating an improvement in the ventilatory condition of the animals after surgical correction of Nostril stenosis. Therefore, it is concluded that arterial hemogasometry is an important diagnostic tool for the diagnosis of brachycephalic respiratory syndrome and is extremely useful in monitoring the patient's response to treatment. Rhinoplasty was effective in the treatment of respiratory syndrome, promoting improvement in hemogasometric parameters that indicate respiratory acidosis secondary to airway obstruction, common in the brachycephalic races.(AU)

Hemogasometria arterial pré e pós-rinoplastia em cães braquicefálicos portadores de estenose de narina / Arterial hemogasometry pre and post rhinoplasty in brachyphalic dogs with nostril stenosis

Vinte e seis cães braquicefálicos portadores de estenose de narina, 22 machos e quatro fêmeas, foram submetidos à rinoplastia bilateral. Dezesseis cães eram Buldogues Franceses; dois, Buldogues Ingleses; seis, Pugs; e dois, Shih Tzus, com idade variando de seis meses a seis anos. Foram efetuadas coletas de sangue arterial para análises hemogasométricas no pré-operatório e 30 dias após a cirurgia. Para cada avaliação, foi obtida uma amostra de 0,5mL de sangue coletado da artéria femoral, em seringa plástica heparinizada. Em seguida, procedeu-se à avaliação hemogasométrica em analisador de gases sanguíneos (I-stat-Abbot®). Os resultados da hemogasometria pré e pós-rinoplastia mostraram uma redução nos valores médios de pCO2, TCO2 , HCO3- e BEecf, hematócrito e hemoglobina, e aumento de pH, pO2 e SO2, indicando melhora na condição ventilatória dos animais após a correção cirúrgica da estenose de narina. Isso posto, conclui-se que a hemogasometria arterial é um exame importante no diagnóstico da síndrome respiratória dos cães braquicefálicos, e extremamente útil no acompanhamento da resposta do paciente ao tratamento. A rinoplastia mostrou-se eficaz no tratamento da síndrome respiratória, promovendo melhora nos parâmetros hemogasométricos que indicam acidose respiratória secundária à obstrução das vias aéreas, comum nas raças braquicefálicas.(AU)

Twenty-six brachycephalic dogs with nostril stenosis, 22 males and four females, underwent bilateral rhinoplasty. Sixteen dogs were French Bulldogs; two, English Bulldogs; Six, Pugs; and two, Shih tzus, ranging in age from six months to six years. Blood samples were collected for hemogasometric analysis in the preoperative period and 30 days after surgery. For each evaluation, a 0.5ml sample of blood collected from the femoral artery was obtained in a heparinized plastic syringe. Hemogasometric evaluation was then performed on a blood gas analyzer (I-stat-Abbot®). The results of hemogasometry before and after rhinoplasty showed a reduction in the mean values of pCO2, TCO2, HCO3- and BEecf, hematocrit and hemoglobin, and an increase in pH, pO2 and SO2, indicating an improvement in the ventilatory condition of the animals after surgical correction of Nostril stenosis. Therefore, it is concluded that arterial hemogasometry is an important diagnostic tool for the diagnosis of brachycephalic respiratory syndrome and is extremely useful in monitoring the patient's response to treatment. Rhinoplasty was effective in the treatment of respiratory syndrome, promoting improvement in hemogasometric parameters that indicate respiratory acidosis secondary to airway obstruction, common in the brachycephalic races.(AU)

Cell-free antigens from precocious Paracoccidioides brasiliensis culture induce a typical delayed-type hypersensitivity reaction

Cell-free antigens (CFAg) derived from Paracoccidioides brasiliensis have typically been used in immunodiffusion reactions for serodiagnosis or therapeutic follow-up of paracoccidioidomycosis patients. Thus, we investigated the usefulness of CFAg obtained from cultures at different ages, to evaluate cellular immunity by the footpad test, in experimental murine paracoccidioidomycosis. Male mice infected with P. brasiliensis 265 strain were challenged in the footpad with CFAg obtained from four- (4d CFAg) or 11-day-old cultures (11d CFAg). The increase in footpad swelling provoked by 4d CFAg and 11d CFAg was similar and showed significant difference in relation to control groups. However, the infiltrate pattern was strikingly different: 4d CFAg induced a predominant mononuclear infiltrate whereas 11d CFAg provoked a predominant polymophonuclear infiltrate. These different inflammatory patterns were associated with distinct electrophoretic characteristics. By comparison with 11d CFAg, 4d CFAg showed more numerous and intense bands, including a strong one of 43 kDa (gp43). These results suggest that CFAg derived from Pb 265 isolate can be used as a reagent to evaluate cellular immunity; however, the culture's age is critical because only young cultures are able to induce a typical mononuclear infiltrate. The efficacy of this new paracoccidioidin to assay the cellular immunity in infections caused by other P. brasiliensis isolates is under investigation.(AU)

Neutralization of pharmacological and toxic activities of Bothrops jararacussu snake venom and isolated myotoxins by Serjania erecta methanolic extract and its fractions

Most of the snakebites recorded in Brazil are caused by the Bothrops genus. Given that the local tissue damage caused by this genus cannot be treated by antivenom therapy, numerous studies are focusing on supplementary alternatives, such as the use of medicinal plants. Serjania erecta has already demonstrated anti-inflammatory, antiseptic and healing properties. In the current study, the aerial parts of S. erecta were extracted with methanol, then submitted to chromatographic fractionation on a Sephadex LH20 column and eluted with methanol, which resulted in four main fractions. The crude extract and fractions neutralized the toxic activities of Bothrops jararacussu snake venom and isolated myotoxins (BthTX-I and II). Results showed that phospholipase A2, fibrinogenolytic, myotoxic and hemorrhagic activities were inhibited by the extract. Moreover, the myotoxic and edematous activities induced by BthTX-I, and phospholipase A2 activity induced by BthTX-II, were inhibited by the extract of S. erecta and its fraction. The clotting time on bovine plasma was significantly prolonged by the inhibitory action of fractions SF3 and SF4. This extract is a promising source of natural inhibitors, such as flavonoids and tannins, which act by forming complexes with metal ions and proteins, inhibiting the action of serineproteases, metalloproteases and phospholipases A2.(AU)

Biochemical and biological evaluation of gyroxin isolated from Crotalus durissus terrificus venom

Gyroxin, a thrombin-like enzyme isolated from Crotalus durissus terrificus venom and capable of converting fibrinogen into fibrin, presents coagulant and neurotoxic activities. The aim of the present study was to evaluate such coagulant and toxic properties. Gyroxin was isolated using only two chromatographic steps - namely gel filtration (Sephadex G-75) and affinity (Benzamidine Sepharose 6B) - resulting in a sample of high purity, as evaluated by RP-HPLC C2/C18 and electrophoretic analysis that showed a molecular mass of 30 kDa. Gyroxin hydrolyzed specific chromogenic substrates, which caused it to be classified as a serine proteinase and thrombin-like enzyme. It was stable from pH 5.5 to 8.5 and inhibited by Mn²+, Cu²+, PMSF and benzamidine. Human plasma coagulation was more efficient at pH 6.0. An in vivo toxicity test showed that only behavioral alterations occurred, with no barrel rotation. Gyroxin was not able to block neuromuscular contraction in vitro, which suggests that its action, at the studied concentrations, has no effect on the peripheral nervous system.(AU)

Functional and structural characterization of phospholipases A² isolated from Bothrops asper snake venom in Panamá

Envenoming by Bothrops snakes is the most serious type of envenoming from the medical and economic point of view in Central America. Bothrops asper is responsible for 90% of the snakebites registered in Panamá every year. Despite its medical and economic relevance, only the venom of Costa Rican and Guatemalan populations of this species has been studied to some detail, and there is very little information on intraspecies variability in venom composition and toxicity. In this study the crude venom of B. asper from Panamá was characterized and its pharmacological and biochemistry activities were investigated with standard laboratory assays. Furthermore, we described the isolation, functional and structural characterization of four basic phospholipases A2, namely MTX-I, MTX-II, MTX-III, MTX-IV, and a new acid phospholipase A2 called Basp-I-PLA2. The proteins were isolated from the crude venom by a combination of two chromatographic steps, using ion-exchange chromatography on CM-Sepharose (0.05 M NH4HCO3 pH 8.1 buffer), and hydrophobic chromatography on Phenyl-Sepharose (0.05 M Tris-HCl pH 7.4), followed by concentration gradient from 4 to 0 M NaCl at 25°C in the same buffer. Analyses of phospholipids hydrolyzed by these enzymes have shown that all phospholipases belong to type A2. The acidic isoform demonstrated more catalytic activity than basic PLA2s. This enzyme was more active on substrates such as phosphotidylcholine and phosphatidylglycerol.(AU)

Functional and structural characterization of phospholipases A2 isolated from Bothrops asper snake venom in Panamá

Envenoming by Bothrops snakes is the most serious type of envenoming from the medical and economic point of view in Central America. Bothrops asper is responsible for 90% of the snakebites registered in Panamá every year. Despite its medical and economic relevance, only the venom of Costa Rican and Guatemalan populations of this species has been studied to some detail, and there is very little information on intraspecies variability in venom composition and toxicity. In this study the crude venom of B. asper from Panamá was characterized and its pharmacological and biochemistry activities were investigated with standard laboratory assays. Furthermore, we described the isolation, functional and structural characterization of four basic phospholipases A2, namely MTX-I, MTX-II, MTX-III, MTX-IV, and a new acid phospholipase A2 called Basp-I-PLA2. The proteins were isolated from the crude venom by a combination of two chromatographic steps, using ion-exchange chromatography on CM-Sepharose (0.05 M NH4HCO3 pH 8.1 buffer), and hydrophobic chromatography on Phenyl-Sepharose (0.05 M Tris-HCl pH 7.4), followed by concentration gradient from 4 to 0 M NaCl at 25°C in the same buffer. Analyses of phospholipids hydrolyzed by these enzymes have shown that all phospholipases belong to type A2. The acidic isoform demonstrated more catalytic activity than basic PLA2s. This enzyme was more active on substrates such as phosphotidylcholine and phosphatidylglycerol. The isoelectric focusing evidenced pIs between 8.1 to 8.3 for MTXs and 4.6 for the isoform Basp-I-PLA2. The molecular weight was estimated by mass spectrometry to be: MTX-1 = 14,156.5; MTX-2 = 14,249.5 and MTX-3 = 14,253.0 and Basp-I-PLA2 = 14,246.0.8 Da.(AU)

Low-level laser therapy decreases local effects induced by myotoxins isolated from Bothrops jararacussu snake venom

The prominent myotoxic effects induced by Bothrops jararacussu crude venom are due, in part, to its polycationic myotoxins, BthTX-I and BthTX-II. Both myotoxins have a phospholipase A2 structure: BthTX-II is an active enzyme Asp-49 PLA2, while BthTX-I is a Lys-49 PLA2 devoid of enzymatic activity. In this study, the effect of low-level laser therapy (LLLT), 685 nm laser at a dose of 4.2 J/cm2 on edema formation, leukocyte influx and myonecrosis caused by BthTX-I and BthTX-II, isolated from Bothrops jararacussu snake venom, was analyzed. BthTX-I and BthTX-II caused a significant edema formation, a prominent leukocyte infiltrate composed predominantly by neutrophils and myonecrosis in envenomed gastrocnemius muscle. LLLT significantly reduced the edema formation, neutrophil accumulation and myonecrosis induced by both myotoxins 24 hours after the injection. LLLT reduced the myonecrosis caused by BthTX-I and BthTX-II, respectively, by 60 and 43%; the edema formation, by 41 and 60.7%; and the leukocyte influx, by 57.5 and 51.6%. In conclusion, LLLT significantly reduced the effect of these snake toxins on the inflammatory response and myonecrosis. These results suggest that LLLT should be considered a potential therapeutic approach for treatment of local effects of Bothrops species venom.(AU)

Antiophidian properties of plant extracts against Lachesis muta venom

Snakebites comprise a serious health problem in several countries due to their global incidence, which exceeds 2.5 million per year, and the elevated number of victim fatalities. To counteract envenomations, antivenoms have been used regularly for more than a century. Apart from side effects including anaphylactic reactions, antivenoms are not able to efficiently neutralize local tissue damage, which contributes to increasing the severity and morbidity observed in patients. This fact, in turn, may be responsible for economic hardship, particularly in rural populations of developing countries. In the present work, we evaluated the antiophidian properties of 12 Brazilian plant extracts against the hemolytic, coagulant, hemorrhagic and proteolytic effects of Lachesis muta venom. Taken together, our data revealed that most of these aqueous products were capable of inhibiting those activities at different levels, except for Sapindus saponaria extract. In contrast, Stryphnodendron barbatiman extract completely neutralized all the analyzed biological activities. Thus, we may conclude that Brazilian flora may also be useful against L. muta accidents.(AU)

Anti-inflammatory activity of Blutaparon portulacoides ethanolic extract against the inflammatory reaction induced by Bothrops jararacussu venom and isolated myotoxins BthTX-I and II

This article reports the anti-inflammatory effect of Blutaparon portulacoides (B. portulacoides), specifically the ethanolic extract of its aerial parts, on the edema formation and leukocyte influx caused by Bothrops jararacussu (B. jararacussu) snake venom and Bothropstoxin-I and II (BthTX-I and II) isolated from this venom as an alternative treatment for Bothrops snakebites. The anti-inflammatory effect of B. portulacoides ethanolic extract was compared with an animal group pretreated with dexamethasone. B. portulacoides ethanolic extract significantly inhibited paw edema induced by B. jararacussu venom and by BthTX-I and II. Also, results demonstrated that the extract caused a reduction of the leukocyte influx induced by BthTX-I. However, the extract was not capable of inhibiting the leukocyte influx induced by the venom and by BthTX-II. In conclusion, these results suggest that the ethanolic extract of this plant possess components able to inhibit or inactivate toxins present in B. jararacussu venom, including its myotoxins, responsible for the edema formation. However, the leukocyte migration caused by the venom and BthTX-II was not inhibited by the plant, probably due to the different mechanisms involved in the edema formation and leukocyte influx. This is the first report of B. portulacoides extract as anti-inflammatory against snake venoms and isolated toxins.(AU)

Purification and functional characterization of two fibrinogenolytic enzymes from Bothrops alternatus venom

Two fibrinogenolytic enzymes, Bothrops alternatus metalloprotease isoform (BaltMP)-I and II, were purified from Bothrops alternatus venom using Diethylaminoethyl (DEAE) Sephacel, Sephadex G-75 and Heparin-Agarose column chromatography. Purified BaltMP-I and II ran as single protein bands on analytical polyacrylamide gel electrophoresis and showed molecular weights of 29000 and 36000, respectively, under reducing conditions in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). BaltMP-II, but not BaltMP-I, displayed blood-clotting activity in bovine plasma, which was about 10-fold higher than that of the crude venom. Both enzymes were proteolytically active against bovine fibrinogen as substrate. When fibrinogen and each enzyme were incubated at 37°C, at a ratio of 1:100 (w/w), BaltMP-II cleaved preferentially the Aalpha -chain and more slowly the Bbeta -chain. The action of BaltMP-I was similar, but lower. None of the proteases degraded the gamma-chain of fibrinogen. The fibrinogenolytic activity of the enzymes was inhibited by 1,10-phenanthroline, suggesting they are metalloproteases. Since both enzymes were found to cause defibrinogenation when intraperitoneally (i.p.) administered to mice, they can be of medical interest as a therapeutic agent in the treatment and prevention of arterial thrombosis.(AU)

Inhibition of L-glutamate and GABA synaptosome uptake by crotoxin, the major neurotoxin from Crotalus durissus terrificus venom

This paper describes a brief study on the crotoxin mechanism of action, regarding the transport of GABA and L-glutamate in rats cortico-cerebral synaptosomes and in heterologous systems, such as COS-7 cells expressing gabaergic transporters, and C6 glioma cells and Xenopus oocytes expressing glutamatergic transporters. Crotoxin concentrations over 1 µM caused an inhibitory effect of ³H-L-glutamate and ³H-GABA, and reversibly inhibited L-glutamate uptake by C6 glioma cells. When COS-7 cells were assayed, no inhibition of the ³H-GABA transport could be evidenced. Crotoxin kept its inhibitory effect on neurotransmitters uptake even when Ca2+ ions were removed from the medium, therefore, independently of its PLA2 activity. In addition, high concentrations (2 mM) of BPB did not avoid the action of crotoxin on the neurotransmitters uptake. Crotoxin also inhibited ³H-L-glutamate, independently on Na+ channel blockade by TTX. In addition, an evaluation of the lactic dehydrogenase activity indicated that uptake inhibition does not involve a hydrolytic action of crotoxin upon the membrane. We may also suggest that crotoxin acts, at least partially, altering the electrogenic equilibrium, as evidenced by confocal microscopy, when a fluorescent probe was used to verify cell permeability on C6 glioma cells in presence of crotoxin.