Biochemistry of the Envenomation Response-a Generator Theme for Interdisciplinary Integration

The understanding of complex physiological processes requires information from many different areas of knowledge. To meet this interdisciplinary scenario, the ability of integrating and articulating information is demanded. The difficulty of such approach arises because, more often than not, information is fragmented through under graduation education in Health Sciences. Shifting from a fragmentary and deep view of many topics to joining them horizontally in a global view is not a trivial task for teachers to implement. To attain that objective we proposed a course herein described Biochemistry of the envenomation response aimed at integrating previous contents of Health Sciences courses, following international recommendations of interdisciplinary model. The contents were organized by modules with increasing topic complexity. The full understanding of the envenoming pathophysiology of each module would be attained by the integration of knowledge from different disciplines. Active-learning strategy was employed focusing concept map drawing. Evaluation was obtained by a 30-item Likert-type survey answered by ninety students; 84% of the students considered that the number of relations that they were able to establish as seen by concept maps increased throughout the course. Similarly, 98% considered that both the theme and the strategy adopted in the course contributed to develop an interdisciplinary view.

Topical Delivery of Lycopene Using Microemulsions: Enhanced Skin Penetration and Tissue Antioxidant Activity

Topical delivery of lycopene is a convenient way to supplement cutaneous levels of antioxidants. In this study, lycopene was incorporated (0.05%, w/w) in two microemulsions containing BRIJ-propylene glycol (2:1, w/w, surfactant blend) but different oil phases: mono/diglycerides of capric and caprylic acids (MG) or triglycerides of the same fatty acids (TG). Microemulsions containing MG and TG were isotropic, fluid, and clear, with internal phase diameters of 27 and 52 nm, respectively. Both MG- or TG-containing microemulsions markedly increased lycopene penetration in the stratum corneum, (6- and 3.6-fold, respectively) and in viable layers of porcine ear skin 2 (from undetected to 172.6 +/- 41.1 and 103.1 +/- 7.2 ng/cm(2), respectively) compared to a control solution. To assure that lycopene delivered to the skin was active, the antioxidant activity of skin treated with MG-containing microemulsion was determined by CUPRAC assay, and found to be 10-fold higher than untreated skin. The cytotoxicity of MG-containing microemulsion in cultured fibroblasts was similar to propylene glycol (considered safe) and significantly less than of sodium lauryl sulfate (a moderate-to-severe irritant) at 1-50 mu g/mL. These results demonstrate that the MG-containing microemulsion is an efficient and safe system to increase lycopene delivery to the skin and the antioxidant activity in the tissue. (C) 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:1346-1357, 2010

Oxidation of oxa and thia fatty acids and related compounds catalysed by 5-and 15-lipoxygenase

The modified fatty acids, (Z,Z,Z)-(octadeca-6,9,12-trienyloxy)acetic acid, (Z,Z,Z)-(octadeca-9,12,15-trienyloxy)acetic acid, (all-Z)-(eicosa-5,8,11,14-tetraenyloxy)acetic acid, (all-Z)-(eicosa-5,8,11,14-tetraenylthio)acetic acid, 3-[(all-Z)-(eicosa-5,8,11,14-tetraenylthio)]propionic acid, (all-Z)-(eicosa-5,8,11,14-tetraenylthio)succinic acid, N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]glycine and N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]aspartic acid, all react with soybean 15-lipoxygenase. The products were treated with triphenylphosphine to give alcohols, which were isolated using HPLC. Analysis of the alcohols using negative ion tandem electrospray mass spectrometry, and by comparison with compounds obtained by autoxidation of arachidonic acid, shows that each enzyme catalysed oxidation occurs at the omega -6 position of the substrate. In a similar fashion, it has been found that (Z,Z,Z)-(octadeca-6,9,12-trienyloxy)acetic acid, (Z,Z,Z)-(octadeca-9,12,15-trienyloxy)acetic acid, (all-Z)-(eicosa-5,8,11,14-tetraenylthio)acetic acid and N-[(all-Z)-(eicosa-5,8, 11.14-tetraenylthio)]propionic acid each undergoes regioselective oxidation at the carboxyl end of the polyene moiety on treatment with potato 5-lipoxygenase. Neither (all-Z)-(eicosa-5,8,11,14-tetraenylthio)succinic acid nor N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]aspartic acid reacts in the presence of this enzyme, while N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]glycine affords the C11' oxidation product. The alcohol derived from (Z,Z,Z)-(octadeca-6,9, 12-trienyloxy)acetic acid using the 15-lipoxygenase reacts at the C6' position with the 5-lipoxygenase. (C) 2001 Elsevier Science Ltd. All rights reserved.

The interaction of metal ions and Marimastat with matrix metalloproteinase 9

The effect of a range of metal ions on the ability of Marimastat to inhibit matrix metalloproteinase 9 (MMP-9) was examined in a fluorescence based proteolytic assay. Whilst none of the metals examined significantly affected the inhibitory ability of Marimastat, several metal ions did have a significant effect on MMP-9 activity itself. In the absence of Marimastat, Zn(II) and Fe(II) significantly inhibited MMP-9 activity at metal ion concentrations of 10 and 100 muM, respectively. In both the absence and presence of Marimastat, Cd(II) significantly inhibited MMP-9 at 100 muM. In contrast, 1 mM Co(II) significantly upregulated MMP-9 proteolytic activity. (C) 2003 Elsevier Science Inc. All rights reserved.

Can metal complexes serve as hypoxia activated prodrugs? Investigations of a Co(III) complex of the MMP inhibitor marimastat

For many years proof that the hypoxic nature of malignant tumours can be used to selectively target anticancer drugs has been sought. Several classes of potential redox activated anticancer drugs have been developed to take advantage of the reducing environment resulting from the hypoxia. Drug complexes with redox active metal centres as carriers have been investigated, but have largely been employed with cytotoxic drugs that require release of the drug intracellularly, complicating the design of such complexes. MMP inhibitors, a new class of anticancer drug, conversely act in the extracellular environment and we have investigated inhibitor complexes with several redox active transition metals. Marimastat is an MMP inhibitor with potent in-vitro antimetastatic activity and was recently in Phase III clinical trials for a variety of cancer types. We have synthesised a Co(II1) complex of marimastat incorporating the tetradentate ligand tpa (tris(2-methylpyridyl)amine) as a carrier ligand. The complex was structurally characterised in the solid state by single crystal X-ray diffraction, the first example of a crystal structure containing marimastat. 2D COSY and NOESY NMR spectra showed that the complex exists in two isomeric forms in solution, corresponding to the cis and trans isomers yet only crystallises in one of these forms. Biological testing of the complex in mice with 4T1.2 tumours showed interesting and unexpected outcomes. Initial results of the tumour growth inhibition study showed that a significant inhibition of growth was exhibited by the complex over the free inhibitor and the control. However, the metastatic potential of both free marimastat and the complex were higher than the control indicating likely problems with the experimental protocol. Further experiments are needed to determine the potential of such complexes as hypoxia activated prodrugs but there appears at least to be some promise.

Iron Metabolism: From Health to Disease

Background Iron is vital for almost all living organisms by participating in a wide range of metabolic processes. However, iron concentration in body tissues must be tightly regulated since excessive iron may lead to microbial infections or cause tissue damage. Disorders of iron metabolism are among the most common human diseases and cover several conditions with varied clinical manifestations. Methods An extensive literature review on the basic aspects of iron metabolism was performed, and the most recent findings on this field were highlighted as well. Results New insights on iron metabolism have shed light into its real complexity, and its role in both healthy and pathological states has been recognized. Important discoveries about the iron regulatory machine and imbalances in its regulation have been made, which may lead in a near future to the development of new therapeutic strategies against iron disorders. Besides, the toxicity of free iron and its association with several pathologies has been addressed, although it requires further investigations. Conclusion This review will provide students in the fields of biochemistry and health sciences a brief and clear overview of iron physiology and toxicity, as well as imbalances in the iron homeostasis and associated pathological conditions.

Why Public Health Agencies Cannot Depend on Good Laboratory Practices as a Criterion for Selecting Data: The Case of Bisphenol A

In their safety evaluations of bisphenol A (BPA), the U.S. Food and Drug Administration (FDA) and a counterpart in Europe, the European Food Safety Authority (EFSA), have given special prominence to two industry-funded studies that adhered to standards defined by Good Laboratory Practices (GLP). These same agencies have given much less weight in risk assessments to a large number of independently replicated non-GLP studies conducted with government funding by the leading experts in various fields of science from around the world. OBJECTIVES: We reviewed differences between industry-funded GLP studies of BPA conducted by commercial laboratories for regulatory purposes and non-GLP studies conducted in academic and government laboratories to identify hazards and molecular mechanisms mediating adverse effects. We examined the methods and results in the GLP studies that were pivotal in the draft decision of the U.S. FDA declaring BPA safe in relation to findings from studies that were competitive for U.S. National Institutes of Health (NIH) funding, peer-reviewed for publication in leading journals, subject to independent replication, but rejected by the U.S. FDA for regulatory purposes. DISCUSSION: Although the U.S. FDA and EFSA have deemed two industry-funded GLP studies of BPA to be superior to hundreds of studies funded by the U.S. NIH and NIH counterparts in other countries, the GLP studies on which the agencies based their decisions have serious conceptual and methodologic flaws. In addition, the U.S. FDA and EFSA have mistakenly assumed that GLP yields valid and reliable scientific findings (i.e., "good science"). Their rationale for favoring GLP studies over hundreds of publically funded studies ignores the central factor in determining the reliability and validity of scientific findings, namely, independent replication, and use of the most appropriate and sensitive state-of-the-art assays, neither of which is an expectation of industry-funded GLP research. CONCLUSIONS: Public health decisions should be based on studies using appropriate protocols with appropriate controls and the most sensitive assays, not GLP. Relevant NIH-funded research using state-of-the-art techniques should play a prominent role in safety evaluations of chemicals.

Factores asociados a fenómeno de no reflujo coronario en pacientes adultos llevados a angioplastia

Introducción: La disminución de flujo en los vasos coronarios sin presencia de oclusión, es conocido como fenómeno de no reflujo, se observa después de la reperfusión, su presentación oscila entre el 5% y el 50% dependiendo de la población y de los criterios diagnósticos, dicho suceso es de mal pronóstico, aumenta el riesgo de morir en los primeros 30 días posterior a la angioplastia (RR 2,1 p 0,038), y se relaciona con falla cardiaca y arritmias, por eso al identificar los factores a los cuales se asocia, se podrán implementar terapias preventivas. Metodología: Estudio de casos y controles pareado por médico que valoró el evento, para garantizar que no existieron variaciones inter observador, con una razón 1:4 (18:72), realizado para identificar factores asociados a la presencia de no reflujo en pacientes llevados a angioplastia, entre noviembre de 2010 y mayo de 2014, en la Clínica San Rafael de Bogotá, D.C. Resultados: La frecuencia del no reflujo fue del 2.89%. El Infarto Agudo de Miocardio con elevación del ST (IAMCEST) fue la única variable que mostró una asociación estadísticamente significativa con este suceso, valor de p 0,002, OR 8,7, IC 95% (2,0 – 36,7). Discusión: El fenómeno de no reflujo en esta población se comportó de manera similar a lo descrito en la literatura, siendo el IAMCEST un factor fuertemente asociado.

Kinetic models as a route to control acrylamide formation in food

Reports that heat processing of foods induces the formation of acrylamide heightened interest in the chemistry, biochemistry, and safety of this compound. Acrylamide-induced neurotoxicity, reproductive toxicity, genotoxicity, and carcinogenicity are potential human health risks based on animal studies. Because exposure of humans to acrylamide can come from both external sources and the diet, there exists a need to develop a better understanding of its formation and distribution in food and its role in human health. To contribute to this effort, experts from eight countries have presented data on the chemistry, analysis, metabolism, pharmacology, and toxicology of acrylamide. Specifically covered are the following aspects: exposure from the environment and the diet; biomarkers of exposure; risk assessment; epidemiology; mechanism of formation in food; biological alkylation of amino acids, peptides, proteins, and DNA by acrylamide and its epoxide metabolite glycidamide; neurotoxicity, reproductive toxicity, and carcinogenicity; protection against adverse effects; and possible approaches to reducing levels in food. Cross-fertilization of ideas among several disciplines in which an interest in acrylamide has developed, including food science, pharmacology, toxicology, and medicine, will provide a better understanding of the chemistry and biology of acrylamide in food, and can lead to the development of food processes to decrease the acrylamide content of the diet.

NOVEL AMINO ACID TRANSPORTER-TARGETED RADIOTRACERS FOR BREAST CANCER IMAGING

Breast cancer is the most common malignancy among women in the world. Its 5-year survival rate ranges from 23.4% in patients with stage IV to 98% in stage I disease, highlighting the importance of early detection and diagnosis. 18F-2-Fluoro-2-deoxy-glucose (18F-FDG), using positron emission tomography (PET), is the most common functional imaging tool for breast cancer diagnosis currently. Unfortunately, 18F-FDG-PET has several limitations such as poorly differentiating tumor tissues from inflammatory and normal brain tissues. Therefore, 18F-labeled amino acid-based radiotracers have been reported as an alternative, which is based on the fact that tumor cells uptake and consume more amino acids to sustain their uncontrolled growth. Among those radiotracers, 18F-labeled tyrosine and its derivatives have shown high tumor uptake and great ability to differentiate tumor tissue from inflammatory sites in brain tumors and squamous cell carcinoma. They enter the tumor cells via L-type amino acid transporters (LAT), which were reported to be highly expressed in many cancer cell lines and correlate positively with tumor growth. Nevertheless, the low radiosynthesis yield and demand of an on-site cyclotron limit the use of 18F-labeled tyrosine analogues. In this study, four Technetium-99m (99mTc) labeled tyrosine/ AMT (α-methyl tyrosine)-based radiotracers were successfully synthesized and evaluated for their potentials in breast cancer imaging. In order to radiolabel tyrosine and AMT, the chelators N,N’-ethylene-di-L-cysteine (EC) and 1,4,8,11-tetra-azacyclotetradecane (N4 cyclam) were selected to coordinate 99mTc. These chelators have been reported to provide stable chelation ability with 99mTc. By using the chelator technology, the same target ligand could be labeled with different radioisotopes for various imaging modalities for tumor diagnosis, or for internal radionuclide therapy in future. Based on the in vitro and in vivo evaluation using the rat mammary tumor models, 99mTc-EC-AMT is considered as the most suitable radiotracer for breast cancer imaging overall, however, 99mTc-EC-Tyrosine will be more preferred for differential diagnosis of tumor from inflammation.

Studies on the adhesion properties of the liver-metastatic murine RAW117 large-cell lymphoma cells: Roles of $\beta\sb3$ integrin

Metastasis is the major cause of death in cancer patients. Since many cancers show organ-preference of metastasis, elucidation of the underlying mechanisms of metastasis will benefit diagnosis or treatment of metastatic diseases. Adhesion mechanisms are thought to be involved in organ-preference of metastasis, because metastatic cells show organ preference in adhering to organ-derived microvascular endothelial cells. The adhesion molecules in this process remain largely unidentified. I have examined a series of murine RAW117 large-cell lymphoma cells variants selected in vivo for liver-colonizing properties ($\rm{H10{>>}L17>P}$). The highly liver-metastatic H10 cells were found to differentially express much higher levels of integrin $\alpha\rm\sb{v}\beta\sb3$ than L17 or P cells. H10 cells also adhered at higher rates to vitronectin and fibronectin than to fibrinogen, fibrin, laminin and type I collagen, and adhered at significantly higher rates to (GRGDS)$\sb4$ than to monomeric RGD-peptides. In contrast, P and L17 cells did not adhere well to the above substrates. H10 cells also spread well on vitronectin and migrated toward vitronectin concentration gradients. Pretreament of H10 cells with anti-$\beta\sb3$ monoclonal antibodies resulted in significant decreases in adhesion of H10 cells to vitronectin and immobilized (GRGDS)$\sb4$, and reduced the formation of experimental liver metastases in syngeneic Balb/c mice.^ Adhesion of RAW117 cells under hydrodynamic shear stresses was also studied because tumor cell adhesion occurs under fluid shear stresses in target organ microvessels. Similar to their properties found with static adhesion assays, H10 cells stabilized their hydrodynamic adhesion to vitronectin, fibronectin and (GRGDS)$\sb4$ much more quickly than P or L17 cells. Unlike their static adhesion properties, RAW117 cells showed differential adhesion stabilization to liver-sinusoidal endothelial cell-derived extracellular matrix ($\rm{H10{>>}L17>P}$). Although not supporting static adhesion of RAW117 cells, monomeric RGD-peptides mediated adhesion stabilization of H10 cells but not L17 or P cells. Integrin $\rm\alpha\sb{v}\beta\sb3$ was found to be involved in stabilizing H10 cell adhesion to vitronectin, (GRGDS)$\sb4$, monomeric RGD-peptide R1, and liver sinusoidal endothelial cell-derived extracellular matrix.^ This study is the first to provide evidence that integrin $\rm\alpha\sb{v}\beta\sb3$ is differentially expressed in liver-metastatic lymphoma cells and involved in differential adhesion of these cells. The results indicate that strong static adhesion and especially the unique hydrodynamic adhesion of RAW117 cells to the RGD-containing substrates correlate with liver-metastatic potentials. Thus, integrin $\rm\alpha\sb{v}\beta\sb3$ may play an important role in liver-preferential metastasis of RAW117 large-cell lymphoma cells. ^