Biomedical subjects

O A Cunha

Publications and source records attributed to O A Cunha.

6 recordsLinked to original sources

PubMed1997

Biochemical and histopathological alterations induced in rats by Tityus serrulatus scorpion venom and its major neurotoxin tityustoxin-I.

Intravenous injection into the rat of sublethal doses of Tityus serrulatus scorpion venom (100 micrograms protein/kg) or its major neurotoxin tityustoxin-I (TsTX-I, 20 micrograms/kg) caused, 30-180 min after injection, statistically significant increases in the serum levels of aspartate aminotransferase, amylase, creatine kinase and lactate dehydrogenase, as well as hyperglycemia, a high level of plasma free fatty acids and a low level of liver glycogen. The in vitro serum levels of the above enzymes did not change. For alanine aminotransferase, gamma-glutamyl transferase and alkaline phosphatase, neither in vitro nor in vivo alterations were observed. The whole venom and TsTX-I caused hepatic congestion with hemolysis and hydropic degeneration. Other histological lesions included edema and congestion with subpleural hemorrhage in the lungs, hypertrophy of fibers with degeneration areas in the heart, and congestion and hemorrhage in the kidneys. In the salivary glands, alterations to the acini and ductules were visible. In the adrenal glands no morphological alterations could be detected at the studied doses. The results suggest that the in vivo enzymatic and histopathological alterations are due to tissue lesions evoked by the whole venom and TsTX-I. An indirect effect, however, induced by stimulation of acetylcholine and catecholamine release in the postganglionic nerve terminals, cannot be excluded.

Animals↗

PubMed1997

Isolation and characterization of a new clotting factor from Bothrops jararacussu (jararacuçu) venom.

A detailed procedure for the isolation of a new clotting enzyme from the venom of Bothrops jararacussu (common name jararacuçu) is described. The estimated mol. wt of the native protein was 30,100 but 37,500 after reduction by dithiothreitol. Two major close bands corresponding to pI 5.18 and 5.20 were detected by electrofocusing but, after methanolysis, a single band focused at pI 8.20. The mol. wt of the protein moiety of this glycoprotein was 28,500, showing V-V-G-A-D-N-C-N-F-N... as N-terminal sequence. The content of neutral sugar was 4.8% and that of total sugars 5.3%. This clotting factor degraded only the A alpha-chain of the fibrinogen molecule. The stability of the clot, when produced in the presence of aprotinin opens new uses for snake clotting enzymes in the production of fibrin glue.

Amino Acids↗

PubMed1997

Inhibition of proteases, myotoxins and phospholipases A2 from Bothrops venoms by the heteromeric protein complex of Didelphis albiventris opossum serum.

The antibothropic complex (ABC) from opossum (species Didelphis albiventris) serum was purified by chromatography on DEAE-Sephacel. It showed an acidic character and two polypeptide chains of ca. 45 kDa and 48 kDa, respectively. Lyophilized opossum serum or the ABC (100 micrograms), as well as ethylenediamine tetraacetate (0.25 mumoles) were able to completely neutralise the hemorrhagic effect of 50 micrograms of the desiccated venoms of Bothrops moojeni, Bothrops pirajai and Bothrops jararacussu. The myotoxic (100 micrograms venom in mice) and edematogenic (90 micrograms venom in rats) activities of Bothrops moojeni and Bothrops jararacussu venoms, as well as of the major myonecrotic protein (myotoxin-I) isolated from Bothrops moojeni venom, were also totally inhibited by the ABC (200 micrograms and 270 micrograms, respectively). The lyophilized opossum serum (30 micrograms) and the ABC (30 micrograms) reduced to 50% the phospholipase A2 activity of Bothrops moojeni venom (10 micrograms). The clotting activity of Bothrops alternatus and Bothrops moojeni (20 micrograms) on bovine plasma was also significantly inhibited by the ABC (60 micrograms).

Animals↗

PubMed1995

Fractionation of Bothrops pirajai snake venom: isolation and characterization of piratoxin-I, a new myotoxic protein.

Whole desiccated venom of Bothrops pirajai was fractionated on a gel filtration (Sephadex G-75) column. Phospholipase A2, arginine esterase and clotting activity profiles of the six fractions (SI to SVI) obtained were determined. Fraction SIV from the gel filtration column was subjected to chromatography on SP-Sephadex C-25. It was resolved into five subfractions (SIV-SP1, to SIV-SP5). Fractions SIV-SP1, SIV-SP2 and SIV-SP3 showed phospholipase A2 activity but, among these fractions, only SIV-SP3 was homogeneous. Induction of myonecrosis by SIV-SP3, SIV-SP4 and SIV-SP5 was demonstrated by their ability to release serum creatine kinase, and for SIV-SP5, to induce histological alterations in the injected mouse muscle. Chemical characterization by determination of mol. wts, isoelectric focusing and direct manual sequencing of the N-terminal region was performed for SIV-SP3, SIV-SP4 and SIV-SP5. When compared with bothropstoxin-I, the myotoxin SIV-SP5 showed the same total number of amino acid residues (121) and constant molar ratio for all but three amino acids. We have named this toxin piratoxin-I (PrTX-I).

Amino Acid Sequence↗

PubMed1995

[Modified Fontan's operation].

Nine-year-old female patient presented with cianosis since she was born, fatique and dyspnea when sucking. The diagnosis was univentricular heart with left ventricular morphology, transposition of the great arteries, moderate pulmonary valve stenosis and atrial septal defect. Submitted to surgical correction with superior vena cava-right pulmonary artery anastomosis, inferior vena cava anastomosis using lateral tunnel, with cardiopulmonary bypass. After surgical correction, the clinical and laboratorial (echocardiogram and cardiac catheterization) evaluation showed Fontan operation with good surgical results. Total cavopulmonary connection was proposed as a modification of the Fontan procedure that might have greater benefits than previous proposed techniques. The results demonstrate that this modification provides excellent early definitive treatment, increasing hemodynamic profile, with low morbidity and mortality, for a variety of complex congenital heart lesions.

Child↗

PubMed1990

Isolation and characterization of hemorrhagic, myonecrotic and edema-inducing toxins from Bothrops insularis (jararaca ilhoa) snake venom.

Bothrops insularis snake venom was fractionated by gel filtration on Sephadex G-150 followed by ion-exchange chromatography on SP-Sephadex C-25. Two active fractions were purified to homogeneity: (1) SIII-SpI, approximate mol. wt 32,000 and N-terminal amino acid residue Val. This fraction showed esterase activity on TAME, edema-inducing activity on the rat hind paw and contractile activity on the isolated guinea pig ileum. The latter two activities were antagonized by benadryl plus methysergide; (2) SIII-SpVI, a myonecrotic and edema-inducing phospholipase, approximate mol. wt 29,000, N-terminal amino acid residue pyro-Glu, consisting of two chains of approximately 15,000 mol. wt each linked by disulphide bridge(s). The induction of edema by this fraction was not antagonized by benadryl plus methysergide, indomethacin, BW755C or BN52021, but it was antagonized by dexamethasone. Three highly purified hemorrhagic heterodimeric fractions, SIII-SpIII-3, SIII-SpIII-4 and SIII-SpIII-5, of approximate mol. wts 26,000, 29,000 and 26,000, and having N-terminal residues of Asx, Asx and Gly, respectively, were further isolated by preparative polyacrylamide slab gel electrophoresis. SIII-SpIII-4 and SIII-SpIII-5 increased the recalcification time of citrated rat plasma. None of the five isolated fractions showed any proteolytic (on casein) or kininogenase activity.

Animals↗