Pituitary Apoplexy After a Single Dose of Long-Acting Octreotide

Pituitary apoplexy (PA) is a rare and potentially life-threatening syndrome resulting from an acute infarction or hemorrhage of the pituitary gland. Although the pathogenesis is not fully understood, some predisposing factors such as pituitary stimulation tests, diabetes mellitus, anticoagulant or antiplatelet aggregation therapy, head trauma, and high blood pressure may play a role in its pathophysiology. Octreotide is the mainstay of medical treatment for acromegaly. The majority of reported complications of octreotide therapy are gastrointestinal. We report the case of a 51-year-old acromegalic woman who developed pituitary apoplexy within the context of high blood pressure and a single dose of long-acting octreotide. Our data suggest that the combination of hypertension and octreotide therapy enhances the risk of pituitary apoplexy.

Pediatric Antiphospholipid Syndrome: Clinical and Immunologic Features of 121 Patients in an International Registry

OBJECTIVES. The purpose of this study was to obtain data on the association of antiphospholipid antibodies with clinical manifestations in childhood and to enable future studies to determine the impact of treatment and long-term outcome of pediatric antiphospholipid syndrome.PATIENTS and METHODS. A European registry extended internationally of pediatric patients with antiphospholipid syndrome was established as a collaborative project of the European Antiphospholipid Antibodies Forum and Lupus Working Group of the Pediatric Rheumatology European Society. To be eligible for enrollment the patient must meet the preliminary criteria for the classification of pediatric antiphospholipid syndrome and the onset of antiphospholipid syndrome must have occurred before the patient's 18th birthday.RESULTS. As of December 1, 2007, there were 121 confirmed antiphospholipid syndrome cases registered from 14 countries. Fifty-six patients were male, and 65 were female, with a mean age at the onset of antiphospholipid syndrome of 10.7 years. Sixty (49.5%) patients had underlying autoimmune disease. Venous thrombosis occurred in 72 (60%), arterial thrombosis in 39 (32%), small-vessel thrombosis in 7 (6%), and mixed arterial and venous thrombosis in 3 (2%). Associated nonthrombotic clinical manifestations included hematologic manifestations (38%), skin disorders (18%), and nonthrombotic neurologic manifestations (16%). Laboratory investigations revealed positive anticardiolipin antibodies in 81% of the patients, anti-beta(2)-glycoprotein I antibodies in 67%, and lupus anticoagulant in 72%. Comparisons between different subgroups revealed that patients with primary antiphospholipid syndrome were younger and had a higher frequency of arterial thrombotic events, whereas patients with antiphospholipid syndrome associated with underlying autoimmune disease were older and had a higher frequency of venous thrombotic events associated with hematologic and skin manifestations.CONCLUSIONS. Clinical and laboratory characterization of patients with pediatric antiphospholipid syndrome implies some important differences between antiphospholipid syndrome in pediatric and adult populations. Comparisons between children with primary antiphospholipid syndrome and antiphospholipid syndrome associated with autoimmune disease have revealed certain differences that suggest 2 distinct subgroups. Pediatrics 2008; 122: e1100-e1107

Phospholipase A(2) myotoxins from Bothrops snake venoms: Structure-function relationship

Phospholipases A(2) constitute the major components from Bothrops snake venoms and have been extensively investigated not only because they are relatively very abundant in these venoms but mainly because they display a range of many relevant biological effects, including: myotoxic, cytotoxic, edema-inducing, artificial membrane disrupting, anticoagulant, neuromuscular, platelet aggregation inhibiting, hypotensive, bactericidal, anti-HIV, anti-tumoural, anti-malarial and anti-parasitic. The primary structures of several PLA(2)s have been elucidated through direct amino acid sequencing or, inderectly, through the corresponding nucleotide sequencing. Two main subgroups were thus described: (i) Asp49 PLA(2)s, showing low (basic, highly myotoxic) to relatively high (acidic, less or non myotoxic) Ca++-dependent hydrolytic activity upon artificial substrates; (ii) Lys49 PLA(2)s (basic, highly myotoxic) , showing no detectable hydrolytic activity on artificial substrates. Several crystal structures of Lys49 PLAs from genus Bothrops have already been solved, revealing very similar fold patterns. Lack of catalytic activity of myotoxic Lys49-PLA(2)s, first related solely with the fact that Lys49 occupies the position of the calcium ion in the catalyticly active site of Asp49 PLA(2)s, is now also attributed to Lys122 which interacts with the carbonyl of Cys29 hyperpolarising the peptide bond between Cys29 and Gly30 and trapping the fatty acid product in the active site, thus interrupting the catalytic cycle. This hypothesis, supported for three recent structures, is also discussed here. All Asp49 myotoxins showed to be pharmacologically more potent when compared with the Lys49 variants, but phospholipid hydrolysis is not an indispensable condition for the myotoxic, cytotoxic, bactericidal, anti-HIV, anti-parasitic, liposome disrupting or edema-inducing activities. Recent studies on site directed mutagenesis of the recombinant Lys49 myotoxin from Bothrops jararacussu revealed the participation of important amino acid residues in the membrane damaging and myotoxic activities.

Structure of BthA-I complexed with p-bromophenacyl bromide: possible correlations with lack of pharmacological activity

The crystal structure of an acidic phospholipase A(2) isolated from Bothrops jararacussu venom (BthA-I) chemically modified with p-bromophenacyl bromide (BPB) has been determined at 1.85 angstrom resolution. The catalytic, platelet-aggregation inhibition, anticoagulant and hypotensive activities of BthA-I are abolished by ligand binding. Electron-density maps permitted unambiguous identification of inhibitor covalently bound to His48 in the substrate-binding cleft. The BthA-I-BPB complex contains three structural regions that are modified after inhibitor binding: the Ca2+-binding loop, ss-wing and C-terminal regions. Comparison of BthA-I-BPB with two other BPB-inhibited PLA(2) structures suggests that in the absence of Na+ ions at the Ca2+- binding loop, this loop and other regions of the PLA(2)s undergo structural changes. The BthA-I-BPB structure reveals a novel oligomeric conformation. This conformation is more energetically and conformationally stable than the native structure and the abolition of pharmacological activities by the ligand may be related to the oligomeric structural changes. A residue of the `pancreatic' loop (Lys69), which is usually attributed as providing the anticoagulant effect, is in the dimeric interface of BthA-I-BPB, leading to a new hypothesis regarding the abolition of this activity by BPB.

Molecular and functional characterization of a new non-hemorrhagic metalloprotease from Bothrops jararacussu snake venom with antiplatelet activity

BjussuMP-II is an acidic low molecular weight metalloprotease (Mr similar to 24,000 and pI similar to 6.5), isolated from Bothrops jararacussu snake venom. The chromatographic profile in RP-HPLC and its N-terminal sequence confirmed its high purity level. Its complete cDNA was obtained by RT-PCR and the 615 bp codified for a mature protein of 205 amino acid residues. The multiple alignment of its deduced amino acid sequence and those of other snake venom metalloproteases showed a high structural similarity, mainly among class P-I proteases. The molecular modeling analysis of BjussuMP-II showed also conserved structural features with other SVMPs. BjussuMP-II did not induce hemorrhage, myotoxicity and lethality, but displayed dose-dependent proteolytic activity on fibrinogen, collagen, fibrin, casein and gelatin, keeping stable at different pHs, temperatures and presence of several divalent ions. BjussuMP-II did not show any clotting or anticoagulant activity on human citrated plasma, in contrast to its inhibitory effects on platelet aggregation. The aspects broached, in this work, provide data on the relationship between structure and function, in order to better understand the effects elicited by snake venom metalloproteases. (c) 2007 Elsevier B.V. All rights reserved.

Cloning and Identification of a Complete cDNA Coding for a Bactericidal and Antitumoral Acidic Phospholipase A(2) from Bothrops jararacussu Venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

beta-glucans in promoting health: Prevention against mutation and cancer

The polysaccharides beta-glucans occur as a principal component of the cellular walls. Some microorganisms, such as yeast and mushrooms, and also cereals such as oats and barley, are of economic interest because they contain large amounts of beta-glucans. These substances stimulate the immune system, modulating humoral and cellular immunity, and thereby have beneficial effect in fighting infections (bacterial, viral, fungal and parasitic). beta-Glucans also exhibit hypocholesterolemic and anticoagulant properties. Recently, they have been demonstrated to be anti-cytotoxic, antimutagenic and anti-tumorogenic, making them promising candidate as pharmacological promoters of health. (C) 2008 Elsevier B.V. All rights reserved.

Freqüência da mutação 844ins68 do gene da cistationina beta-sintetase em pacientes com trombose venosa profunda

A hiper-homocisteinemia, resultante da deficiência na conversão da homocisteína em cistationina, constitui em fator de risco isolado para doenças vasculares. A mutação 844ins68 do gene da cistationina beta-sintetase é um fator adicional de risco para a trombose venosa profunda. O objetivo deste estudo foi avaliar a freqüência da mutação 844ins68 do gene da cistationina beta-sintetase em pacientes com trombose venosa profunda. Foram avaliados em estudo caso-controle 95 pacientes com trombose venosa profunda, a presença da mutação 844ins68 no éxon 8 do gene da cistationina beta-sintetase. Como critério de inclusão foi adotada a presença de trombose venosa profunda confirmada pelo dúplex ou flebografia. O grupo controle constituiu-se de 95 doadores de sangue, sem história familiar prévia de trombose venosa, com sexo, grupo étnico e idades pareados aos do grupo de estudo. Foram coletados 5 mL de sangue venoso com o uso de anticoagulante EDTA de cada participante. O DNA foi extraído dos leucócitos pelo método DTAB e CTAB. A detecção da mutação do gene foi realizada por amplificação de um segmento gênico por PCR, com iniciadores que flanqueiam a região de inserção e com revelação em gel de agarose a 2%, corado com brometo de etídio, sob luz UV. O fragmento correspondente ao alelo normal contém 184 pares de base e o correspondente ao alelo mutante, 252 pares de base. O teste exato de Fisher foi utilizado na análise dos resultados. A condição heterozigota para a mutação foi encontrada em 14,73% dos pacientes e em 3,1% dos indivíduos do grupo controle (p = 0,009). A freqüência do alelo mutante mostrou diferença significativa (p = 0,01), sendo 0,074 para os pacientes versus 0,016 para o grupo controle. Não foram encontrados casos de homozigose.

Lack of association between ABO histo-blood groups, secretor and non-secretor phenotypes, and anti-Toxoplasma gondii antibodies among pregnant women from the northwestern region of São Paulo State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Insights into metal ion binding in phospholipases A(2): ultra high-resolution crystal structures of an acidic phospholipase A(2) in the Ca2+ free and bound states

The electrophile Ca2+ is an essential multifunctional co-factor in the phospholipase A(2) mediated hydrolysis of phospholipids. Crystal structures of an acidic phospholipase A(2) from the venom of Bothrops jararacussu have been determined both in the Ca2+ free and bound states at 0.97 and 1.60 angstrom resolutions, respectively. In the Ca2+ bound state, the Ca2+ ion is penta-coordinated by a distorted pyramidal cage of oxygen and nitrogen atoms that is significantly different to that observed in structures of other Group I/II phospholipases A(2). In the absence of Ca2+, a water molecule occupies the position of the Ca2+ ion and the side chain of Asp49 and the calcium-binding loop adopts a different conformation. (c) 2005 Elsevier SAS. All rights reserved.

Thrombomodulin-independent activation of protein C and specificity of hemostatically active snake venom serine proteinases - Crystal structures of native and inhibited Agkistrodon contortrix contortrix protein C activator

Protein C activation initiated by the thrombin-thrombomodulin complex forms the major physiological anticoagulant pathway. Agkistrodon contortrix contortrix protein C activator, a glycosylated single-chain serine proteinase, activates protein C without relying on thrombomodulin. The crystal structures of native and inhibited Agkistrodon contortrix contortrix protein C activator determined at 1.65 and 1.54 angstrom resolutions, respectively, indicate the pivotal roles played by the positively charged belt and the strategic positioning of the three carbohydrate moieties surrounding the catalytic site in protein C recognition, binding, and activation. Structural changes in the benzamidine-inhibited enzyme suggest a probable function in allosteric regulation for the anion-binding site located in the C-terminal extension, which is fully conserved in snake venom serine proteinases, that preferentially binds Cl1- instead of SO42-.

Avaliação do desempenho dos reagentes do tempo de tromboplastina parcial ativada utilizados para detectar o anticoagulante lúpico

INTRODUÇÃO: O anticoagulante lúpico é uma imunoglobulina pertencente à família dos anticorpos antifosfolípides. A sua ação in vitro é interferir nos testes de coagulação dependentes de fosfolípides. O tempo de tromboplastina parcial ativada (TTPA) é um teste utilizado como screening na pesquisa do anticoagulante lúpico. Os reagentes utilizados neste teste apresentam grandes variações quanto à sensibilidade. OBJETIVO: Avaliar o desempenho dos reagentes do TTPA e detectar a presença do anticoagulante lúpico através de diferentes testes da coagulação. MATERIAL E MÉTODO: A pesquisa do anticoagulante lúpico foi realizada em 50 amostras plasmáticas de pacientes do sexo feminino através dos testes do TTPA, do tempo de coagulação do caulim (TCC), do tempo de tromboplastina parcial ativada diluída (TTPAd) e do tempo do veneno da víbora de Russel diluído (TVVRd). Três cefalinas comerciais foram avaliadas pelos testes do TTPA e do TTPAd. Na comparação entre os reagentes estudados foi aplicado o cálculo do intervalo de confiança (95%). RESULTADOS: Os três reagentes avaliados apresentaram boa concordância e os métodos utilizados responderam bem à pesquisa do anticoagulante lúpico. DISCUSSÃO E CONCLUSÃO: As três cefalinas comerciais avaliadas podem ser utilizadas na rotina laboratorial para a pesquisa do anticoagulante lúpico.

Comparação do efeito do ácido etilenodiaminotetracético (EDTA) e da heparina sobre os eritrócitos de avestruzes (Struthio camelus L.)

Anticoagulantes com diferentes formas de ação têm sido utilizados na hematologia aviária. Entretanto, poucos estudos foram publicados sobre seu efeito e sobre os parâmetros hematológicos dos avestruzes. Visando a preencher essa lacuna, realizou-se um estudo em que foi comparado o efeito de dois anticoagulantes de rotina (EDTA - 2 mg/mL sangue e da Heparina -10U/mL sangue) sobre os eritrócitos de avestruzes. Para tanto, foram avaliados a integridade, o volume globular e a morfometria dos eritrócitos de amostras sanguíneas de 20 aves, tratadas com ambos os anticoagulantes. A integridade eritrocitária foi estimada pelo grau de hemoglobina livre no plasma, sendo o volume globular obtido pelo método de micro-hematócrito e os dados morfométricos (área, diâmetro maior e menor) calculados automaticamente em sistema computadorizado de imagem digital de alta resolução. A hemólise estimada pela dosagem de hemoglobina plasmática, o volume globular, a área e o diâmetro máximo dos eritrócitos foram significativamente maiores nas amostras tratadas com EDTA. Para melhor preservar a integridade e a morfometria dos eritrócitos, concluiuse que a heparina é um anticoagulante mais adequado que o EDTA para avaliar as discrasias eritrocitárias dos avestruzes.

Apresentação pediátrica da síndrome antifosfolípide

OBJETIVO: Descrever as características clínicas, laboratoriais e de desfecho de uma série de casos com diagnóstico definido de síndrome antifosfolípide (SAF) pediátrica. MÉTODOS: Estudo observacional-retrospectivo de referência pediátrica terciária, que identificou os casos por meio de evento vascular, trombose venosa ou oclusão arterial, determinação de anticorpos anticardiolipina (IgG e IgM) e teste do anticoagulante lúpico. RESULTADOS: Foram identificados cinco casos atendidos nos últimos cinco anos, sendo dois meninos e três meninas. A trombose venosa ocorreu em seios venosos cerebrais (2), fibular (2), poplítea (1), femoral (1), intestinal (1), renal (1), acompanhados por oclusão arterial intestinal (1), de artéria renal (1) e artéria digital (1), esta resultando gangrena periférica como evento recorrente durante anticoagulação com warfarina. Um abortamento espontâneo ocorreu em uma adolescente em vigência de púrpura trombocitopênica, evoluindo com anemia hemolítica (síndrome de Evans) e desfecho fatal por hemorragia. A investigação laboratorial em todos os casos resultou, pelo menos, uma determinação positiva de anticardiolipina IgG e/ou IgM, sendo considerados como SAF primária. Três dos casos estão em seguimento com anticoagulação oral. CONLUSÃO: A trombose venosa cerebral e de extremidades foram os eventos mais freqüentes. A presente série alerta para a investigação e o diagnóstico precoces, com abordagem multidisciplinar para o tratamento.

ANTAGONISM OF THE MYOTOXIC EFFECTS OF BOTHROPS-JARARACUSSU VENOM AND BOTHROPSTOXIN BY POLYANIONS

The effects of heparin and other polyanions on the myotoxicity of Bothrops jararacussu venom and purified bothropstoxin (BthTX) were investigated. The release rate of creatine kinase (CK) from isolated extensor digitorum longus muscle and the plasma CK activity of mice were used to quantify the results. The myotoxic effects of B. jararacussu venom or BthTX were inhibited by preincubation of these agents with one of the following: a heterogeneous heparin preparation (designated 'heparin'), low mol. wt heparin (H-4500) or dextran sulfates (DS-8000 and DS-500,000). Non-sulfated dextran (D-40,000) and two chondroitin sulfates were ineffective. The antimyotoxic effects of the polyanions are ascribed to their forming inactive acid-base complexes with the basic myotoxins of Bothrops venoms. Gel-filtration experiments in Sephadex provided direct evidence for complex formation between heparin and BthTX. Intravenous (i.v.) administration of H-4500 or DS-8000 opposed the increase in plasma CK activity induced by a subsequent i.m. injection of venom or BthTX. In contrast, pretreatment with i.v. heparin or DS-500,000 enhanced the venom-induced increase in plasma CK activity. This effect was not observed (1) when the animals were treated with a polyvalent antivenom, which inhibits the coagulation and local stasis induced by Bothrops venoms, and (2) when BthTX, which has no thrombotic or hemorrhagic properties, was the myotoxic agent. The potentiation of the venom-induced increase in plasma CK activity by heparin and DS-500,000 is ascribed to improved washout of the CK released from damaged fibers, because of the anticoagulant properties of the drugs.