Ana Maria B Martinez

Fundação Universidade Federal do Rio Grande (FURG), São Pedro do Rio Grande do Sul, Rio Grande do Sul, Brazil

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Publications (6)11.73 Total impact

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    ABSTRACT: We investigated the myotoxicity of Bothrops jararacussu crude venom and other cytolytic agents on mouse isolated extensor digitorum longus (EDL) and soleus (SOL) muscles, which present distinct properties: EDL is a fast-twitch, white muscle with predominantly glycolytic fibers, while SOL is slow-twitch, red muscle with predominantly oxidative fibers. Muscles were exposed to B. jararacussu crude venom (25 microg/ml) and other crotaline venoms (Agkistrodon contortrix laticinctus; Crotalus viridis viridis; Crotalus durissus terrificus) at the same concentration. Basal creatine kinase (CK) release to bathing solution was 0.43+/-0.06 for EDL and 0.29+/-0.06 for SOL (U g(-)(1) h(-)(1), n=36 for each muscle). Sixty minutes after exposure to B. jararacussu venom, EDL presented higher increase in the rate of CK release than SOL, respectively, 13.2+/-1.5 and 2.9+/-0.7 U g(-)(1)h(-)(1), n=10-12. Muscle denervation, despite decreasing CK content, did not affect sensitivities to B. jararacussu venom. Ouabain and potassium channel blockers (TEA; clotrimazole; glibenclamide) increased the rate of CK release by B. jararacussu in EDL and SOL muscles, decreasing and almost abolishing the different sensitivity. When we exposed EDL or SOL muscles to Naja naja, Apis mellifera venoms (25 microg/ml), or Triton X-100 (0.01%), they showed similar rate of CK release. Our present data suggest that a mechanism involving intracellular calcium regulation or potassium channels may participate in the different sensitivity of EDL and SOL to B. jararacussu venom.
    Toxicon 08/2008; 52(4):551-8. · 2.92 Impact Factor
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    ABSTRACT: The Testing and Counseling Centers are important sources of epidemiological information. This study describes a research conducted with the users of the Testing and Counseling Center of Rio Grande-RS submitted to anti-HIV test during the period 2001-2004. Demographic and behavioral factors of individuals attended in the service were analyzed using the database SISCTA-2002/RG. HIV-1 seropositivity between 2001 and 2004 was of 1,1%; 2,4%; 2,3% and 1,7%, respectively. In 2003 and 2004, 37,7% and 36% of the HIV-1 positive patients did not return to the Testing and Counseling Center for getting the result of their serological anti-HIV or confirmatory tests. These results seem to reflect some tendencies of the HIV epidemic in Rio Grande and in Brazil. It is important to emphasize the high percentage of HIV-1 positive patients who do not return for getting the result of their test. In terms of public health this risk behavior may jeopardize the efforts for controlling the epidemic.
    Ciencia & saude coletiva 06/2008; 13(3):1033-40.
  • Ciencia & Saude Coletiva - CIENC SAUDE COLETIVA. 01/2008; 13(3).
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    ABSTRACT: To evaluate the impact of HIV-1 CRF31_BC in the southern Brazilian HIV epidemic. Blood plasma from 284 patients was collected from July 2002 to January 2003 at 2 reference HIV/AIDS centers in southern Brazil. Viral protease and reverse transcriptase (RT) genomic regions were amplified by RT polymerase chain reaction, sequenced, and subtyped. Evolutionary analyses were performed to estimate the CRF31_BC most recent common ancestor and its population growth rate with BEAST version 1.3. CRF31_BC was responsible for 7.4% of infections. The average time of HIV diagnosis and the proportion of patients on antiretroviral treatment were shorter for CRF31_BC and subtype C than for subtype B. CRF31_BC was found as early as in 1990 in the Brazilian epidemic. Evolutionary analysis of CRF31_BC revealed that it appeared immediately after the introduction of subtype C in Brazil and has been growing at a similar rate as subtype C. CRF31_BC plays an important role in the HIV epidemic of southern Brazil, and its prevalence has increased throughout the years. This circulating recombinant form corresponds to approximately 25% of total HIV isolates in this region in 2004. Understanding the cause of this spread is important for public health strategies in Brazil and in Latin America.
    JAIDS Journal of Acquired Immune Deficiency Syndromes 08/2007; 45(3):328-33. · 4.65 Impact Factor
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    ABSTRACT: In a previous report we showed that Lachesis muta crude venom displays potent indirect hemolytic activity and myotoxicity when injected into mice. Then, a phospholipase A(2) (PLA(2)) (LM-PLA(2)-I) responsible for these activities was isolated. More recently, a catalytically active isoenzyme (LM-PLA(2)-II) with molecular mass of 18 kDa and isoeletric point at pH 5.4 was isolated from the same snake venom. LM-PLA(2)-II inhibited ADP- and collagen-induced platelet aggregation as well as induced a potent paw edema reaction in rats. Here we show that LM-PLA(2)-II induced myotoxic effects both in vitro characterized by an increase on the rate of creatine kinase (CK) release from isolated mice extensor digitorum longus (EDL) muscles and in vivo by increasing plasma CK activity of injected mice. Histological analysis showed an intense damage in muscle cells injected with LM-PLA(2)-II. It was also shown that exogenous lysophosphatidylcholine (lyso-pc) behaved as a typical myotoxin damaging muscle cells, producing myonecrosis characterized by local infiltration of inflammatory cells similarly to that observed for LM-PLA(2)-II. Hemorrhage and lethal effects were not observed neither with LM-PLA(2)-II nor lyso-pc. As previously observed for other biological activities, pretreatment of LM-PLA(2)-II with p-bromophenacyl bromide (p-BPB) or acetic anhydride abolished all the enzyme's actions. The data confirms that biological activities displayed by LM-PLA(2)-II, including the myotoxic effects reported here, are all dependent on its enzymatic activity where the product formed (lyso-pc) may play an important function on such myotoxicity.
    The International Journal of Biochemistry & Cell Biology 11/2003; 35(10):1470-81. · 4.15 Impact Factor
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    ABSTRACT: In a previous report we showed that Lachesis muta crude venom displays potent indirect hemolytic activity and myotoxicity when injected into mice. Then, a phospholipase A2 (PLA2) (LM-PLA2-I) responsible for these activities was isolated. More recently, a catalytically active isoenzyme (LM-PLA2-II) with molecular mass of 18kDa and isoeletric point at pH 5.4 was isolated from the same snake venom. LM-PLA2-II inhibited ADP- and collagen-induced platelet aggregation as well as induced a potent paw edema reaction in rats. Here we show that LM-PLA2-II induced myotoxic effects both in vitro characterized by an increase on the rate of creatine kinase (CK) release from isolated mice extensor digitorum longus (EDL) muscles and in vivo by increasing plasma CK activity of injected mice. Histological analysis showed an intense damage in muscle cells injected with LM-PLA2-II. It was also shown that exogenous lysophosphatidylcholine (lyso-pc) behaved as a typical myotoxin damaging muscle cells, producing myonecrosis characterized by local infiltration of inflammatory cells similarly to that observed for LM-PLA2-II. Hemorrhage and lethal effects were not observed neither with LM-PLA2-II nor lyso-pc. As previously observed for other biological activities, pretreatment of LM-PLA2-II with p-bromophenacyl bromide (p-BPB) or acetic anhydride abolished all the enzyme’s actions. The data confirms that biological activities displayed by LM-PLA2-II, including the myotoxic effects reported here, are all dependent on its enzymatic activity where the product formed (lyso-pc) may play an important function on such myotoxicity.
    International Journal of Biochemistry & Cell Biology - INT J BIOCHEM CELL BIOL. 01/2003; 35(10):1470-1481.