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Biomedical subjects

A R de Roodt

Publications and source records attributed to A R de Roodt.

10 recordsLinked to original sources
PubMed2001

A study on the experimental envenomation in mice with the venom of Tityus trivitattus Kraepelin 1898 (Scorpiones, Buthidae) captured in Argentina.

Although Tityus trivitattus is the only scorpion species reported to cause severe human envenomation in Argentina, no previous studies on its venom have been done. Telson homogenates from T. trivitattus specimens collected in Santiago del Estero, Cordoba, and Buenos Aires were employed to study their protein composition and toxicity to mice. Regardless of the site of collection, electrophoretic analysis showed bands at 205, 150, 100, 40, 32, and 13 kDa or smaller. FPLC gel filtration showed three major peaks and 6-8 minor peaks with similar elution volumes. One of the minor peaks from FPLC containing a component of approximately 8 kDa was lethal to mice. Mice injected intravenously with different doses of homogenates presented severe autonomic signs like tachypnea, tachycardia, sialorrhea, lacrimation, profuse sweating, diarrhea, dyspnea, and death. Pathology studies of lungs showed severe congestion of alveolar capillaries, pulmonary edema, and hemorrhagic areas. The kidneys showed glomerular as well as tubular lesions and exocrine glands showed areas of necrosis. The calculated LD50 was 0.38 +/- 0.08 telsons per 20 g mouse, which suggests a lethal potency similar to that of T. serrulatus venom. The lethal potency of 5.0 LD50 of T. trivitattus telson homogenate was neutralized by both an anti-T. trivitattus and a heterologous anti Tityus with ED50 values of 41 +/- 19 and 170 +/- 42 microl, respectively.

Animals↗
PubMed2000

Some toxic and enzymatic activities of Bothrops ammodytoides (yarará ñata) venom.

Bothrops ammodytoides, the smallest representative of this genus, is found only in Argentina. Venom was extracted from thirty adult specimens (35-70 cm in length, 90-300 g in weight) captured in the Province of Buenos Aires and kept in captivity. Venom yield was 3-30 mg. SDS-PAGE showed strong bands at 14.0; 23-25; 45; 54 and 63 kDa and weak bands at 17.0; 30.0; 40.0 and 85.0 kDa. Toxic activities were: LD50 (intravenous, mice) 0.5+/-0.2 microg/g; minimal procoagulant dose on human plasma (MPD-P) 35+/-2 mg/l; and minimal defibrinogenating dose (MDD, mice) 6-12 microg. Hemorrhagic and/or necrotic activities appear to play a major role in lethality; minimal hemorrhagic dose (MHD, mice) is 10+/-2 microg/g and minimal necrotizing dose (MND, mice) is 38+/-5 microg. The LD50, MPD-P and MND are among the lowest in venoms from Bothrops species found in Argentina. B. ammodytoides venom exhibited high proteolytic and phospholipase A2 activities. Most of the B. ammodytoides venom components cross-react with Bivalent Bothropic antivenom (Instituto Nacional de Producción de Biológicos ANLIS Dr. G. Malbrin, against B. alternatus and B. neuwiedii venoms). One ml of antivenom neutralizes 1.2 mg of B. ammodytoides venom.

Animals↗
PubMed2000

A comparison of different methods to assess the hemorrhagic activity of Bothrops venoms.

The hemorrhagic activity of Bothrops (B.) alternatus, B. ammodytoides, B. jararaca, B. jararacussu, B. moojeni and B. neuwiedii venoms from specimens captured in Argentina was assayed after i.d. injection to mice. The hemorrhagic haloes produced by each venom had different color intensities, although no significant differences were observed by measurement of the average diameters or the weight of the excised hemorrhagic haloes. Conversely, important differences were found by measuring the amount of hemoglobin extracted from excised hemorrhagic haloes of similar size produced by different venoms. The relationship between the amount of hemoglobin extracted and the weight of the excised hemorrhagic haloes was linear, with a slope (hemoglobin released per gram of hemorrhagic halo) characteristic for each venom, and proportional to the potency. On this basis, the activity of B. alternatus, B. ammodytoides and B. jararaca is similar, about 1.5 times higher than that of B. jararacussu and B. moojeni venoms and threefold higher than that of B. neuwiedii venom. Thus, measurement of the of hemoglobin released provides additional information in comparative studies, and may be used to assess the antihemorrhagic potency of antivenoms.

Animals↗
PubMed2000

[Accidents due to lepidoptera with special reference to Lonomia sp].

Human poisoning by Lepidoptera (butterflies, caterpillars and moths) has been known to physicians since old times. In the last few years, several factors have been causative of a great number of contacts between different stages of these insects and humans, occasionally with epidemic features. Species of medical interest in Argentina are those related to Megalopygidae, Saturniidae, Hemileucidae, Arctiidae, Notodentidae and Eucliedae families. Among all the species involved, it is important to describe the pathology produced by contact with Lonomia obliqua caterpillar (Saturniidae). The caterpillar Lonomia has several enzymes with procoagulant and fibrinolytic activities, acting on various components of the hemostatic system inducing hemorrhage that can lead to death. In the South of Brazil during the last years caterpillars of this butterfly caused a great number of cases of erucism including some deaths. In the past two years, there have been some cases of poisoning by Lonomia obliqua in Misiones, in the North East of Argentina on the border with Southern Brazil. This presents a potential risk, taking into account the poor knowledge regarding this insect and its venom in Argentina. This brief actualization gives some biochemical, clinical and epidemiologic tools towards understanding human Lepidopterism, an uncommon medical problem in this country.

Animals↗
PubMed1999

[Cross neutralization of bothrops jararacussu venom by heterologous antivenoms].

We have studied the immunochemical cross-reactivity and cross-neutralization of the lethal potency, hemorrhagic, necrotizing, procoagulant and (indirect) hemolytic activities of Bothrops jararacussu venom by the standard antivenoms produced in Argentina. These antivenoms are horse immunoglobulin F (ab')2 fragments from animals immunized with 1) Crotalus durissus terrificus venom (Monovalent Anticrotalic antivenom); 2) Bothrops alternatus and B. neuwiedii venoms (Bivalent Botropic antivenom); 3) B. alternatus, B. neuwiedii, B. jararaca and B. jararacussu venoms (Tetravalent Bothropic, or "Misiones" antivenom) and 4) B. alternatus, B. neuwiedii and C. d. terrificus venoms (Trivalent Botropic-Crotalic antivenom). In preincubation experiments, all the heterologous antivenoms neutralized the toxic and biological activities of B. jararacussu venom with a potency at least as high as the Tetravalent Botropic (i.e. the only homologous) antivenom, in which B. jararacussu venom was included as immunogen. These results suggest the possibility of using heterologous antibothropic antivenoms for the treatment of snake bites by B. jararacussu.

Animals↗
PubMed1998

Cross-reactivity and heterologous neutralization of crotaline antivenoms used in Argentina.

The immunochemical cross-reactivity and neutralizing capacity of four crotalinae antivenoms consisting in equine F(ab')2 fragments and available in Argentina (bothropic Bivalent, against Bothrops alternatus and B. neuwiedii venoms; bothropic Tetravalent, against B. alternatus, B. neuwiedii; B. jararaca and B. jararacussu venoms; bothropic crotalic Trivalent, against B. alternatus, B. neuwiedii and Crotalus (C.) durissus terrificus venoms and anticrotalic against C. d. terrificus venom) were studied against B. alternatus, B. ammodytoides; B. jararaca; B. jararacussu, B. moojeni; B. neuwiedii and C. d. terrificus venoms. SDS-PAGE analysis of the Bothrops venoms showed protein bands of high (>40 kDa) medium (20-40 kDa) and low (<15 kDa) molecular weights, while that of C. d. terrificus exhibited a large amount of material with molecular weight of 15.0 kDa or lower. Immunoblotting showed a high cross-reactivity of all the major protein bands with all the antivenoms (even heterologous) tested. All the antivenoms were effective in neutralizing the lethal activity of the venoms tested, and in some cases (B. jararaca and B. jararacussu) heterologous antivenoms exhibited similar neutralizing capacity than the homologous ones. In spite of the differences in biochemical composition and pharmacology, Bothropic antivenoms displayed a significant neutralizing capacity on lethal activity of C. d. terrificus venom. In addition, all the antivenoms (including the anticrotalic) were highly effective in neutralizing the hemorragic, necrotizing, procoagulant, and proteolytic activities. The antivenoms tested produced different degrees of inhibition of phospholipase A2 activity, which exhibited a certain specificity but was also related to the enzyme content in the venom.

Animals↗
PubMed1998

A study on the venom yield of venomous snake species from Argentina.

A study on the venom yield of snakes from Argentina over a three year period was carried out on adult specimens of Bothrops alternatus (n = 74); Bothrops neuwiedii (n = 127); Bothrops ammodytoides (n = 30); Bothrops moojeni (n = 14); Bothrops jararaca (n = 14); B. jararacussu (n = 6); Crotalus durissus terrificus (n = 120) and Micrurus spp. (n = 6) as well as with 12 specimens of newborn C. d. terrificus kept in captivity. While for each species there was a positive correlation between venom yield and number of snakes milked, the correlation with the snake's body weights after individual milkings was even better, suggesting that the size of the snakes is more important in determining the venom yield than the number of snakes milked or the specimen's sex. Individual milkings indicated that, in addition to the snake size, when the amount of venom is normalized per 100 g body weight there is a species specific difference in venom yield. It follows the order B. jararacussu > B. moojeni approximately = B. jararaca approximately = B. alternatus > B. neuwiedii> Micrurus spp approximately = B. ammodytoides> C. d. terrificus. Although the venom yield per 100 g body weight of newborn C. d. terrificus specimens is 2-fold higher than that of adults, no correlation was observed between venom yield and body weight.

Age Factors↗
PubMed1997

[Neutralizing capacity of ++antiophidic sera against the venom of Bothrops moojeni (lance-headed viper)].

In the production of current therapeutic antisera used in Argentina for Bothrops snakebite, the Bothrops moojeni venom is not used as immunogen, since this snake is not considered a serious public health problem. Accidents caused by this species have not been reported in this country even though Bothrops moojeni is not unfrequent in some regions of Misiones. Despite the high degree of immunological cross reactivity found among the Crotalinae venoms and, in this particular case, among the venoms from the Bothrops Genus, there exists a significant intraspecific variation in venom composition, particularly in specimens arising from different geographic regions. In this study, the antivenoms prepared at the Instituto Nacional de Producción de Biológicos A.N.L.I.S. Dr. Carlos G. Malbrán have been tested for their immunochemical cross reactivity and neutralizing ability of enzymatic and toxic activities of venom from Argentinian specimens of Bothrops moojeni from Misiones. Immunological cross-reactivity was tested by double-immunoprecipitation, immunoelectrophoresis, Western-blot and ELISA. Neutralizing ability of antivenoms against proteolytic, indirect hemolytic activity, procoagulant activity, he-morrhagic activity and necrotizing activity. The Lethal Dose 50 was 1.5 mg/kg body weight; this value is located in the range to those obtained with the venom from Brazilian specimens. It was observed that all the antivenoms exhibited a strong immunochemical cross reactivity and that they were able to neutralize in different degree both, enzymatic and toxic activities of B. moojeni venom. From these results, it can be assumed that the antivenom tested could be employed successfully in cases of B. moojeni snakebites.

Animals↗
PubMed1993

[A case of human sparganosis in Argentina].

A male patient from Peru presented a nodule localized in the left costal region. All other clinical and laboratory data were normal. Upon biopsy, an helminth parasite emerged from the subcutaneous tissue, which presented a marked eosinophil infiltrate. The helminth was classified as a plerocercoid larva of Spirometra; the species was not determined. Since Spirometra are not common in Argentina, it is presumed that the patient was infested during his two year sojourn in the peruvian forest. Some epidemiological aspects are discussed. As far as we know, this is the first case of subcutaneous sparganosis and the second of sparganosis reported in Argentina.

Adult↗