A B S T R A C T An asymptomatic woman (Ms. \Vil-liams) was found to have a severe abnormality in the surface-activated intrinsic coagulation, fibrinolvtic, and kinin-generating pathways. Assays for known coagulation factors were normal while Fletcher factor (prekallikrein) was 45%, insufficient to account for the observed markedly prolonged partial thromboplastin time. Plasminogen proactivator was present at 20% of normal levels and addition of highly purified plasminogen proactivator containing 10% plasminogen activator partially corrected the coagulation and fibrinolytic abnormalities but not the kinin-generating defect. This effect was due to its plasminogen activator content. In addition, Williams trait plasma failed to convert prekallikrein to kallikrein or release kiniin upon incubation with kaolin. Kininogen

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A pesquisa médica e biomédica no Brasil. Comparações com o desempenho científico brasileiro e mundial Medical and biomedical research in Brazil. A comparison of Brazilian and international scientific performance Abstract This article compares Brazil's performance in science and technology investment to that of other countries, in relation to basic research, application of knowledge, and researcher training. The article shows a high correlation between GDP and scientific and technological performance in developed countries such as the Unit-Brazil. The comparison to higher-performance countries gave a clearer grasp of Brazil's health research challenge in order to increase the citation indices and better qualify such research. Key words Comparative research in health, Science and technology policy, Brazilian technological development, Investment in health research Resumo Este texto coloca o Brasil no interior dos países que fazem investimento em C&T, de forma comparada, no que concerne a pesquisas básicas, à aplicação do conhecimento e à formação de pesquisadores. Evidencia elevada correlação entre o (PIB) e o desempenho científico e tecnológico de países desenvolvidos como EUA, Japão, A comparação com os países de mais elevado desempenho possibilita melhor situar o desafio a ser vencido pela pesquisa brasileira na área da saúde, para colocá-la no patamar dos índices de citação que melhor qualifica a pesquisa feita na área. Palavras-chave Pesquisa comparada em saúde, Política de C&T, Desenvolvimento tecnológico brasileiro, Investimento em pesquisa em saúde

Canatoxin is a toxic protein from Canavalia ensiformis seeds, lethal to mice (LD(50)=2 mg/kg) and insects. Further characterization of canatoxin showed that its main native form (184 kDa) is a non-covalently linked dimer of a 95 kDa polypeptide containing zinc and nickel. Partial sequencing of internal peptides indicated homology with urease (EC 3.5.1.5) from the same seed. Canatoxin has approx. 30% of urease's activity for urea, and K(m) of 2-7 mM. The proteins differ in their affinities for metal ions and were separated by affinity chromatography on a Zn(2+) matrix. Similar to canatoxin, urease activates blood platelets and interacts with glycoconjugates. In contrast with canatoxin, no lethality was seen in mice injected with urease (10 mg/kg). Pretreatment with p-hydroxymercuribenzoate irreversibly abolished the ureolytic activity of both proteins. On the other hand, p-hydroxymercuribenzoate-treated canatoxin was still lethal to mice, and both treated proteins were fully active in promoting platelet aggregation and binding to glycoconjugates. Taken together, our data indicate that canatoxin is a variant form of urease. Moreover, we show for the first time that these proteins display several biological effects that are unrelated to their enzymic activity for urea.

Accidents with the caterpillar Lonomia obliqua are often associated with a coagulation disorder and hemorrhagic syndrome in humans. In the present study, we have constructed cDNA libraries from two venomous structures of the caterpillar, namely the tegument and the bristle. Highthroughput sequencing and bioinformatics analyses were performed in parallel. Over one thousand cDNAs were obtained and clustered to produce a database of 538 contigs and singletons (clusters) for the tegument library and 368 for the bristle library. We have thus identified dozens of fulllength cDNAs coding for proteins with sequence homology to snake venom prothrombin activator, trypsin-like enzymes, blood coagulation factors and prophenoloxidase cascade activators. We also report cDNA coding for cysteine proteases, Group III phospholipase A2, Ctype lectins, lipocalins, in addition to protease inhibitors including serpins, Kazal-type inhibitors, cystatins and trypsin inhibitor-like molecules. Antibacterial proteins and housekeeping genes are also described. A significant number of sequences were devoid of database matches, suggesting that their biologic function remains to be defined. We also report the N-terminus of the most abundant proteins present in the bristle, tegument, hemolymph, and "cryosecretion". Thus, we have created a catalog that contains the predicted molecular weight, isoelectric point, accession number, and putative function for each selected molecule from the venomous structures of L. obliqua. The role of these molecules in the coagulation disorder and hemorrhagic syndrome caused by envenomation with this caterpillar is discussed. All sequence information and the Supplemental Data, including Figures and Tables with hyperlinks to FASTA-formatted files for each contig and the best match to the Databases, are available at http://www.ncbi.nih.gov/projects/omes.

The salivary anticoagulant of the blood-sucking bug Rhodnius prolixus was purified to homogeneity using a protocol consisting of weak cation-exchange, DEAE, hydrophobic-interaction and octadecyl reverse-phase chromatography, yielding a protein with the same N-terminal sequence as nitrophorin 2, one of the four NO haem protein carriers present in the salivary glands of Rhodnius with a molecular mass of 19689 Da [D. Champagne, R.H. Nussenzveig and J.M.C. Ribeiro, (1995) J. Biol. Chem. 270, in the press]. To exclude the possibility of the nitrophorin being a contaminant, another chromatographic protocol was performed, consisting of chromatofocusing followed by strong-cation-exchange chromatography. Again the anticoagulant was eluted with nitrophorin 2. Nitrophorin 2 inhibits coagulation Factor VIII-mediated activation of Factor X and accounts for all the anti-clotting activity observed in Rhodnius salivary glands.

Phosphodiesterase type 2A (PDE2A) hydrolyzes cyclic nucleotides cAMP and cGMP, thus efficiently controlling cNMP-dependent signaling pathways. PDE2A is composed of an amino-terminal region, two regulatory GAF domains, and a catalytic domain. Cyclic nucleotide hydrolysis is known to be activated by cGMP binding to GAF-B; however, other mechanisms may operate to fine-tune local cyclic nucleotide levels. In a yeast two-hybrid screening we identified XAP2, a crucial component of the aryl hydrocarbon receptor (AhR) complex, as a major PDE2A-interacting protein. We mapped the XAP2 binding site to the GAF-B domain of PDE2A. PDE assays with purified proteins showed that XAP2 binding does not change the enzymatic activity of PDE2A. To analyze whether PDE2A could affect the function of XAP2, we studied nuclear translocation of AhR, i.e. the master transcription factor controlling the expression of multiple detoxification genes. Notably, regulation of AhR target gene expression is initiated by tetrachlorodibenzodioxin (TCDD) binding to AhR and by a poorly understood cAMP-dependent pathway followed by the translocation of AhR from the cytosol into the nucleus. Binding of PDE2A to XAP2 inhibited TCDD-and cAMP-induced nuclear translocation of AhR in Hepa1c1c7 hepatocytes. Furthermore, PDE2A attenuated TCDD-induced transcription in reporter gene assays. We conclude that XAP2 targets PDE2A to the AhR complex, thereby restricting AhR mobility, possibly by a local reduction of cAMP levels. Our results provide first insights into the elusive cAMP-dependent regulation of AhR.