Purification and partial characterization of draculin, the anticoagulant factor present in the saliva of vampire bats (<i>Desmodus rotundus</i>)

From the saliva of the vampire bat Desmodus rotundus, we isolated an unknown anticoagulant protein which we have named draculin. Its molecular mass as determined by non-reduced SDS-PAGE is about 83 kDa. The reduced polypeptide shows a slower migration. HPLC in a molecular sieve matrix yields a single, symmetrical peak corresponding to 88.5 kDa. Isoelectric focusing shows an acidic protein with pI = 4.1–4.2. Aminoacid analysis is compatible with a single chain polypeptide of about 80 kDa. Cyanogen bromide cleavage yields a single 16-aminoacid peptide, corresponding to the amino-terminus of the native molecule. Draculin inhibits the activated form of coagulation factors IX and X. It does not act on thrombin, trypsin, chymotrypsin and does not express fibrinolytic activity. The inhibition is immediate and not readily reversible, with a stoichiometry of about two molecules of draculin per molecule of factor IXa or Xa. Surprisingly, the inhibitory activity against either factor is not affected by the presence of the other. Draculin binds quantitatively to either immobilised factor Xa or factor IXa. Our preliminary interpretation is that there are two forms of draculin that hardly differ in structure. Both bind to factor Xa and to factor IXa but one form inhibits factor Xa and the other inhibits factor IXa. When added to plasma, draculin increases the lag phase as well as the height of the peak of thrombin generation

Ajoene, a garlic compound, inhibits protein prenylation and arterial smooth muscle cell proliferation

1) Ajoene is a garlic compound with anti-platelet properties and, in addition, was shown to inhibit cholesterol biosynthesis by affecting 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase and late enzymatic steps of the mevalonate (MVA) pathway. (2) MVA constitutes the precursor not only of cholesterol, but also of a number of non-sterol isoprenoids, such as farnesyl and geranylgeranyl groups. Covalent attachment of these MVA-derived isoprenoid groups (prenylation) is a required function of several proteins that regulate cell proliferation. We investigated the effect of ajoene on rat aortic smooth muscle cell proliferation as related to protein prenylation. (3) Cell counting, DNA synthesis, and cell cycle analysis showed that ajoene (1-50 micro M) interfered with the progression of the G1 phase of the cell cycle, and inhibited rat SMC proliferation. (4) Similar to the HMG-CoA reductase inhibitor simvastatin, ajoene inhibited cholesterol biosynthesis. However, in contrast to simvastatin, the antiproliferative effect of ajoene was not prevented by the addition of MVA, farnesol (FOH), and geranylgeraniol (GGOH). Labelling of smooth muscle cell cellular proteins with [3H]-FOH and [3H]-GGOH was significantly inhibited by ajoene. (5) In vitro assays for protein farnesyltransferase (PFTase) and protein geranylgeranyltransferase type I (PGGTase-I) confirmed that ajoene inhibits protein prenylation. High performance liquid chromatography (HPLC) and mass spectrometry analyses also demonstrated that ajoene causes a covalent modification of the cysteine SH group of a peptide substrate for protein PGGTase-I. (6) Altogether, our results provide evidence that ajoene interferes with the protein prenylation reaction, an effect that may contribute to its inhibition of SMC proliferatio

Effect of garlic on cardiovascular disorders: a review

Garlic and its preparations have been widely recognized as agents for prevention and treatment of cardiovascular and other metabolic diseases, atherosclerosis, hyperlipidemia, thrombosis, hypertension and diabetes. Effectiveness of garlic in cardiovascular diseases was more encouraging in experimental studies, which prompted several clinical trials. Though many clinical trials showed a positive effect of garlic on almost all cardiovascular conditions mentioned above, however a number of negative studies have recently cast doubt on the efficary of garlic specially its cholesterol lowering effect of garlic. It is a great challenge for scientists all over the world to make a proper use of garlic and enjoy its maximum beneficial effect as it is the cheapest way to prevent cardiovascular disease. This review has attempted to make a bridge the gap between experimental and clinical study and to discuss the possible mechanisms of such therapeutic actions of garlic

Los niveles de ácido fólico en la población venezolana y su impacto en el área de salud pública

Los folatos, constituyen cofactores fundamentales para los procesos bioqu&iacute;micos que conducen a la sintesis y eventual modificaci&oacute;n epig&eacute;netica de &aacute;cidos nucleicos e histonas. Adem&aacute;s, su metabolismo est&aacute; intimamente relacionado al metabolismo de la homocisteina. Se han descrito numerosas causas de mal funcionamiento del ciclo metab&oacute;lico de folatos, la causa m&aacute;s frecuente y quizas la m&aacute;s relevante desde el punto de vista de salud p&uacute;blica es la deficiencia nutricional. El papel central del folato en la sintesis y posteriores modificaciones epigen&eacute;ticas del material gen&eacute;tico, por una parte, as&iacute; como su relaci&oacute;n con la homeostasis de la homocisteina, lo han asociado a dos tipos de patolog&iacute;as de gran importancia en salud p&uacute;blica: a) Enfermedades cardiovasculares y b) Defectos del desarrollo embrionario. En la actualidad, su papel en el riesgo cardiovascular es sujeto de controversia ya que estudios cl&iacute;nicos poblacionales no lo respaldan, sin embargo, si existe evidencia clara de su papel en la aparici&oacute;n de defectos del desarrollo embrionario, especificamente aquellos centrados en el tubo neural y el sistema cardio-circulatorio. Estas evidencias, llevaron a proponer diversos modelos program&aacute;ticos en salud p&uacute;blica para prevenir y tratar a nivel poblacional el deficit nutricional de folatos. De los varios modelos ensayados, la fortificaci&oacute;n obligatoria de ciertos alimentos de consumo masivo ha demostrado ser el mas exitoso y es actualmente implementado en 54 paises a nivel mundial. En Venezuela, desde la decada del 2000 se ha demostrado experimentalmente una seria deficiencia nutricional de folato, que afecta a m&aacute;s del 70% de la poblaci&oacute;n femenina en edad fertil. A pesar de los m&uacute;ltiples llamados hechos a los responsables de las politicas de salud en el pa&iacute;s, Venezuela sigue siendo uno de los pocos paises en la regi&oacute;n que no ha implementado un programa de fortificaci&oacute;n. Su implementaci&oacute;n no requiere de una fuerte inversi&oacute;n oficial, pero si debe ser acompa&ntilde;ado de un programa eficiente de seguimiento que permita a) evaluar los beneficios y b) las posibles modificaciones en su implementaci&oacute;n.The folate cofactors are essential for the biochemical processes that lead to the eventual synthesis and epigenetic modification of histones and nucleic acids. In addition, their metabolism is closely related to homocysteine metabolism. While there have been described numerous causes malfunction folate metabolic cycle, the most common and perhaps the most important cause, from the point of view of public health, is nutritional deficiency. The central role of folate in the synthesis and subsequent epigenetic modifications of genetic material, on the one hand, and their relationship with the homeostasis of homocysteine, have been associated with two types of diseases of great public health importance: a) Cardiovascular Diseases b) Defects of embryonic development. Currently, its role in cardiovascular risk is the subject of controversy since this have not received support from population trials , however, there is clear evidence of their role in the onset of embryonic development defects, specifically those focused on the neural tube and the cardio-circulatory system. This evidence, led to propose different program models in public health, at the population level, to attack the nutritional deficit of folates. Of the several models tested, mandatory fortification of certain foods for mass consumption has proved the most successful and is currently implemented in 54 countries worldwide. In Venezuela, since the 2000s it has been shown, experimentally, a serious nutritional folate deficiency, which affects over 70% of the female population of childbearing age. Despite numerous appeals made to those responsible for health policies in the country, Venezuela remains one of the few countries in the region that has not implemented a program of fortification. Its implementation does not requires a strong government investment, but must also be accompanied by an effective monitoring program that allows a) evaluation of the potential benefits and b) support rational implementation of any necessary changes