Proposal for the interaction of non-conventional partial agonists and catecholamines with the 'putative beta(4)-adrenoceptor' in mammalian heart

1. Evidence for a 'putative beta(4)-adrenoceptor' originated over 20 years ago when cardiostimulant effects were observed to nonconventional partial agonists, These agonists were originally described as beta(1)- and beta(2)-adrenoceptor antagonists; however, they cause cardiostimulant effects at much higher concentrations than those required to block beta(1)- and beta(2)-adrenoceptors. Cardiostimulant effects of non-conventional partial agonists have been observed in mouse, rat, guinea-pig, cat, ferret and human heart tissues, 2. The receptor is expressed in several heart regions, including the sinoatrial node, atrium and ventricle, 3. The receptor is resistant to blockade by most antagonists that possess high affinity for beta(1)- and beta(2)- adrenoceptors, but is blocked with moderate affinity by (-)-bupranolol and CGP 20712A. 4. The receptor is pharmacologically distinct from the beta(3)-adrenoceptor. Micromolar concentrations of beta(3)-adrenoceptor agonists have no agonist or blocking activity, The receptor is also resistant to blockade by a beta(3)-adrenoceptor-selective antagonist. 5. The receptor mediates increases in cAMP levels and cAMP-dependent protein kinase (PK) A activity in cardiac tissues. Phosphodiesterase inhibition potentiates the positive chronotropic and inotropic effects of non-conventional partial agonists. 6. The receptor mediates hastening of atrial and ventricular relaxation, which is consistent with involvement of a cAMP-dependent pathway. 7. The non-conventional partial agonist (-)-[H-3]-CGP 12177A labels the cardiac putative beta(4)-adrenoceptor, Non-conventional partial agonists compete for binding with affinities that are closely similar to their agonist potencies, Catecholamines compete for binding in a stereoselective manner with a rank order of affinity of (-)-R0363 > (-)-isoprenaline > (-)-noradrenaline greater than or equal to (-)-adrenaline much greater than (-)-isoprenaline, suggesting that catecholamines can interact with the receptor. 8. The putative beta(4)-adrenoceptor appears to be coupled to the G(s)-adenylyl cyclase system, which could serve as a guide to its future cloning, Activation of the receptor may plausibly improve diastolic function but could also mediate arrhythmias.

The Genetic Landscape of the Childhood Cancer Medulloblastoma

Medulloblastoma (MB) is the most common malignant brain tumor of children. To identify the genetic alterations in this tumor type, we searched for copy number alterations using high-density microarrays and sequenced all known protein-coding genes and microRNA genes using Sanger sequencing in a set of 22 MBs. We found that, on average, each tumor had 11 gene alterations, fewer by a factor of 5 to 10 than in the adult solid tumors that have been sequenced to date. In addition to alterations in the Hedgehog and Wnt pathways, our analysis led to the discovery of genes not previously known to be altered in MBs. Most notably, inactivating mutations of the histone-lysine N-methyltransferase genes MLL2 or MLL3 were identified in 16% of MB patients. These results demonstrate key differences between the genetic landscapes of adult and childhood cancers, highlight dysregulation of developmental pathways as an important mechanism underlying MBs, and identify a role for a specific type of histone methylation in human tumorigenesis.

SAR calculation using FDTD simulations

The main intend of this work, is to determinate the Specific Absorption Rate (SAR) on human head tissues exposed to radiation caused by sources of 900 and 1800MHz, since those are the typical frequencies for mobile communications systems nowadays. In order to determinate the SAR, has been used the FDTD (Finite Difference Time Domain), which is a numeric method in time domain, obtained from the Maxwell equations in differential mode. In order to do this, a computational model from the human head in two dimensions made with cells of the smallest possible size was implemented, respecting the limits from computational processing. It was possible to verify the very good efficiency of the FDTD method in the resolution of those types of problems.

Transmissão do vírus citomegálico através do aleitamento materno em prematuros

RESUMO: Nas últimas quatro décadas, desenvolveram-se vários estudos, dispersos por todo o mundo, visando analisar a importância da transmissão perinatal do CMV pelo leite materno, nos recém-nascidos prematuros e de baixo peso à nascença. Comparando estes estudos, as taxas de incidência de infecção e doença são extremamente variáveis, não havendo consenso entre os autores. Surgiu, assim, a necessidade de realizar a presente dissertação, pioneira ao nível nacional, com o objectivo de determinar a incidência da infecção perinatal citomegálica, transmitida através do aleitamento materno a recémnascidos prematuros, e identificar as suas consequências clínicas. Para a elaboração deste trabalho foram seleccionados todos os recém-nascidos com idade gestacional inferior a 35 semanas e respectivas mães seropositivas para CMV, internados na Unidade de Cuidados Intensivos de Neonatalogia do Hospital de São Francisco Xavier, entre o período de 1 de Outubro de 2010 e 31 Julho de 2011. Foram analisadas as urinas dos recém-nascidos e o leite materno das mães na primeira, sexta e décima segunda semana pós-parto, utilizando a técnica de Nested-PCR e, posteriormente, a PCR em Tempo Real, para determinar a carga viral do leite materno. Constatou-se que a aquisição da infecção perinatal de CMV no recém-nascido prematuro ocorre com alguma frequência (40,5%), sendo muito provável que a via de transmissão em 38,1% destes casos seja o leite materno infectado, não devendo esta ser desvalorizada. Relativamente às consequências clínicas, não foram observadas alterações clínico-laboratoriais associadas à infecção citomegálica. Analisando os factores que condicionam a transmissão da infecção citomegálica perinatal, estabeleceu-se uma correlação entre a carga viral do leite materno e a transmissão do vírus, permitindo deduzir que quanto maior a carga viral, maior o risco de transmissão. Finalmente, os resultados obtidos sugerem que o risco de transmissão da infecção e suas consequências clínicas não justificam a contra-indicação da amamentação, pois esta comporta, também, elevados benefícios. ----------------ABSTRACT: In the last four decades, several studies were developed all over the world to analyze the importance of CMV perinatal transmission through mother´s milk in the preterm and low birthweight newborns. Comparing these studies, the infection and disease incidence rates are extremely variable, without agreement between the authors. The aim of this study, the first of the kind made in Portugal, is to define the rate of perinatal cytomegalovirus infection in preterm newborns via breastfeeding and its clinical consequences. All the newborns with gestational age below 35 weeks and their CMV seropositive mothers, admitted between the October 1, 2010 and July 31, 2011 in the Neonatology Intensive Care Unit of the São Francisco Xavier Hospital, were included in this study. Human breast milk and urine specimens were collected from mothers and their preterms infants around the 1st, 6th and 12th week after delivery and analyzed by Nested-PCR. The PCR in Real Time was used to determine the breast milk viral load. It was found that the CMV perinatal infection in preterm infants occurs in 40,5% of the cases and most likely 38,1% of these were infected via breastmilk and therefore this should not be overlooked. Considering the clinical consequences, no clinical and laboratory changes associated with cytomegalovirus infection were observed. Analyzing the factors that determine the perinatal transmission of the cytomegalovirus, it was established a correlation between breast milk viral load and viral transmission, allowing to conclude that the higher the viral load the greater the risk of transmission. Finally, the obtained results suggest that the risk of CMV infection and its clinical consequences don´t justify the breastfeeding contraindication because it also provides high benefits.

EVALUATION OF THE THERAPEUTIC EFFICACY OF LEVAMISOLE HYDROCHLORIDE ON THIRD-STAGE LARVAE OF Lagochilascaris minor IN EXPERIMENTALLY INFECTED MICE

Lagochilascariosis, a disease caused by Lagochilascaris minor, affects the neck, sinuses, tonsils, lungs, the sacral region, dental alveoli, eyeballs and the central nervous system of humans. A cycle of autoinfection may occur in human host tissues characterized by the presence of eggs, larvae and adult worms. This peculiarity of the cycle hinders therapy, since there are no drugs that exhibit ovicidal, larvicidal and vermicidal activity. Given these facts, we studied the action of levamisole hydrochloride on third-stage larvae in the migration phase (G1) and on encysted larvae (G3) of L. minor. To this end, 87 inbred mice of the C57BL/6 strain were divided into test groups comprising 67 animals (G1-37; G3-30) and a control group (G2-10; G4-10) with 20 animals. Each animal was inoculated orally with 2,000 infective eggs of the parasite. The animals of the test groups were treated individually with a single oral dose of levamisole hydrochloride at a concentration of 0.075 mg. The drug was administered either 30 minutes prior to the parasite inoculation (G1 animals) or 120 days after the inoculation (G3 animals). The mice in the control groups were not treated with the drug. After the time required for the migration and the encysting of L. minor larvae, all the animals were euthanized and their tissues examined. The data were analyzed using the Student's unpaired t-test and the Levene test. The groups showed no statistically significant difference. Levamisole hydrochloride was ineffective on third-stage larvae of L. minor. These findings explain the massive expulsion of live adult worms, as well as the use of long treatment schemes, owing to the persistence of larvae and eggs in human parasitic lesions.

A glycolytic phenotype is associated with prostate cancer progression and aggressiveness: a role for Monocarboxylate Transporters as metabolic targets for therapy.

Metabolic adaptation is considered an emerging hallmark of cancer, whereby cancer cells exhibit high rates of glucose consumption with consequent lactate production. To ensure rapid efflux of lactate, most cancer cells express high levels of monocarboxylate transporters (MCTs), which therefore may constitute suitable therapeutic targets. The impact of MCT inhibition, along with the clinical impact of altered cellular metabolism during prostate cancer (PCa) initiation and progression, has not been described. Using a large cohort of human prostate tissues of different grades, in silico data, in vitro and ex vivo studies, we demonstrate the metabolic heterogeneity of PCa and its clinical relevance. We show an increased glycolytic phenotype in advanced stages of PCa and its correlation with poor prognosis. Finally, we present evidence supporting MCTs as suitable targets in PCa, affecting not only cancer cell proliferation and survival but also the expression of a number of hypoxia-inducible factor target genes associated with poor prognosis. Herein, we suggest that patients with highly glycolytic tumours have poorer outcome, supporting the notion of targeting glycolytic tumour cells in prostate cancer through the use of MCT inhibitors.

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Cultured primary fetal cells from one organ donation could possibly meet the exigent and stringent technical aspects for development of therapeutic products. These cell types have fewer technological limitations for cellular proliferation capacity (simple culture conditions) and maintenance of differentiated phenotype, and they also have low probability for transmission of communicable diseases. Master and Working Cell Banks (MCB, WCB) can be obtained from one fetal organ donation, permitting multiple tissues (skin, bone, cartilage, muscle and intervertebral disc) to be processed in short periods of time with identical methods to assure a stringent tracing of the processes for the production of standardized therapeutic agents. Clinical use of biologics from embryo and fetal tissues is relatively new and current legislation and ethics have some differences between countries to date. In addition, specific cell delivery systems for each tissue type can be adapted to the clinical application. Since it is the intention that banked primary fetal cells enhance the prospective treatment of hundreds of thousands of patients with only one organ donation, it is imperative to show consistency, traceability and safety of the processes including donor tissue selection, cell banking, cell testing and growth of cells in out-scaling for the preparation of bio-engineered products for clinical application.

Wnt secretion and gradient formation.

Concentration gradients formed by the lipid-modified morphogens of the Wnt family are known for their pivotal roles during embryogenesis and adult tissue homeostasis. Wnt morphogens are also implicated in a variety of human diseases, especially cancer. Therefore, the signaling cascades triggered by Wnts have received considerable attention during recent decades. However, how Wnts are secreted and how concentration gradients are formed remains poorly understood. The use of model organisms such as Drosophila melanogaster has provided important advances in this area. For instance, we have previously shown that the lipid raft-associated reggie/flotillin proteins influence Wnt secretion and spreading in Drosophila. Our work supports the notion that producing cells secrete Wnt molecules in at least two pools: a poorly diffusible one and a reggie/flotillin-dependent highly diffusible pool which allows morphogen spreading over long distances away from its source of production. Here we revise the current views of Wnt secretion and spreading, and propose two models for the role of the reggie/flotillin proteins in these processes: (i) reggies/flotillins regulate the basolateral endocytosis of the poorly diffusible, membrane-bound Wnt pool, which is then sorted and secreted to apical compartments for long-range diffusion, and (ii) lipid rafts organized by reggies/flotillins serve as "dating points" where extracellular Wnt transiently interacts with lipoprotein receptors to allow its capture and further spreading via lipoprotein particles. We further discuss these processes in the context of human breast cancer. A better understanding of these phenomena may be relevant for identification of novel drug targets and therapeutic strategies.

Molecular genetics of "PRPF31" dominant mutations linked to retinitis pigmentosa

ABSTRACT : The retina is one of the most important human sensory tissues since it detects and transmits all visual information from the outside world to the brain. Retinitis pigmentosa (RP) is the name given to a group of inherited diseases that affect specifically the photoreceptors present in the retina and in many instances lead to blindness. Dominant mutations in PRPF31, a gene that encodes for a pre-mRNA splicing factor, cause retinitis pigmentosa with reduced penetrance. We functionally investigated a novel mutation, identified in a large family with autosomal dominant RP, and 7 other mutations, substitutions and microdeletions, in 12 patients from 7 families with PRPF31-linked RP. Seven mutations lead to PRPF31 mRNA with premature stop codons and one to mRNA lacking the exon containing the initiation codon. Quantification of PRPF31 mRNA and protein levels revealed a significant reduction in cell lines derived from patients, compared to non carriers of mutations in PRPF31. Allelic quantification of PRPF31 mRNA indicated that the level of mutated mRNA is very low compared to wild-type mRNA. No mutant protein was detected and the subnuclear localization of wild-type PRPF31 remains the same in cell lines from patients and controls. Blocking nonsense-mediated mRNA decay in cell lines derived from patients partially restored PRPF31 mutated mRNA but derived proteins were still undetectable, even when protein degradation pathways were inhibited. Our results demonstrated that the vast majority of PRPF31 mutations result in null alleles, since they are subject to surveillance mechanisms that degrade mutated mRNA and possibly block its translation. Altogether, these data indicate that the likely cause of PRPF31-linked RP is haploinsufficiency, rather than a dominant negative effect. Penetrance of PRPF31 mutations has been previously demonstrated to be inversely correlated with the level of PRPF31 mRNA, since high expression of wild-type PRPF31 mRNA protects from the disease. Consequently, we have investigated the genetic modifiers that control the expression of PRPF31 by quantifying PRPF31 mRNA levels in cell lines derived from 200 individuals from 15 families representative of the general population. By linkage analyses we identified a 8.2Mb-region on chromosome 14q21-23 that contains a gene involved in the modulation of PRPF31 expression. We also assessed apreviously-mapped penetrance factor invariably located on the wild-type allele and linked to the PRPF31 locus in asymptomatic patients from different families with RP. We demonstrated that this modifier increases the expression of both PRPF31 alleles already at the pre-mRNA level. Finally, our data suggest that PRPF31 mRNA expression and consequently the penetrance of PRPF31 mutations is modulated by at least 2 diffusible compounds, which act on both PRPF31 alleles during their transcription.

Assessing the value of CAN-gene mutations using MALDI-TOF MS.

PURPOSE: To identify cancer-linked genes, Sjöblom et al. and Wood et al. performed a genome-wide mutation screening in human breast and colorectal cancers. 140 CAN-genes were found in breast cancer, which in turn contained overall 334 mutations. These mutations could prove useful for diagnostic and therapeutic purposes. METHODS: We used a MALDI-TOF MS 40-plex assay for testing 40 loci within 21 high-ranking breast cancer CAN-genes. To confirm mutations, we performed single-plex assays and sequencing. RESULTS: In general, the mutation rate of the analyzed loci in our sample cohort was very low. No mutation from the 40 loci analyzed could be found in the 6 cell lines. In tissue samples, a single breast cancer tissue sample showed heterozygosity at locus c.5834G>A within the ZFYVE26 gene (Zinc finger FYVE domain-containing gene 26). CONCLUSIONS: Sjöblom et al./Wood et al. already showed that the vast majority of CAN-genes are mutated at very low frequency. Due to the fact that we only found one mutation in our cohort, we therefore assume that at the selected loci, mutations might be low-frequency events and therefore, more rarely detectable. However, further evaluation of the CAN-gene mutations in larger cohorts should be the aim of further studies.

MYC regulation of a "poor-prognosis" metastatic cancer cell state.

Gene expression signatures are used in the clinic as prognostic tools to determine the risk of individual patients with localized breast tumors developing distant metastasis. We lack a clear understanding, however, of whether these correlative biomarkers link to a common biological network that regulates metastasis. We find that the c-MYC oncoprotein coordinately regulates the expression of 13 different "poor-outcome" cancer signatures. In addition, functional inactivation of MYC in human breast cancer cells specifically inhibits distant metastasis in vivo and invasive behavior in vitro of these cells. These results suggest that MYC oncogene activity (as marked by "poor-prognosis" signature expression) may be necessary for the translocation of poor-outcome human breast tumors to distant sites.

Selection of peptides and synthesis of pentameric peptabody molecules reacting specifically with ErbB-2 receptor.

The HER-2/ErbB-2 oncoprotein is overexpressed in human breast and ovarian adenocarcinomas and is clearly associated with the malignant phenotype. Although no specific ligand for this receptor has been positively identified, ErbB-2 was shown to play a central role in a network of interactions with the related ErbB-1, ErbB-3 and ErbB-4 receptors. We have selected new peptides binding to ErbB-2 extracellular domain protein (ECD) by screening 2 newly developed constrained and unconstrained random hexapeptide phage libraries. Out of 37 phage clones, which bound specifically to ErbB-2 ECD, we found 6 constrained and 10 linear different hexapeptide sequences. Among the latter, 5 consensus motifs, all with a common methionine and a positively charged residue at positions 1 and 3, respectively, were identified. Furthermore, 3 representative hexapeptides were fused to a coiled-coil pentameric recombinant protein to form the so-called peptabodies recently developed in our laboratory. The 3 peptabodies bound specifically to the ErbB-2 ECD, as determined by enzyme-linked immunosorbent assay and BIAcore analysis and to tumor cells overexpressing ErbB-2, as shown by flow cytometry. Interestingly, one of the free selected linear peptides and all 3 peptabodies inhibited the proliferation of tumor cells overexpressing ErbB-2. In conclusion, a novel type of ErbB-2-specific ligand is described that might complement presently available monoclonal antibodies.

Bioconjugated lanthanide luminescent helicates as multilabels for lab-on-a-chip detection of cancer biomarkers.

The lanthanide binuclear helicate [Eu(2)(L(C2(CO(2)H)))(3)] is coupled to avidin to yield a luminescent bioconjugate EuB1 (Q = 9.3%, tau((5)D(0)) = 2.17 ms). MALDI/TOF mass spectrometry confirms the covalent binding of the Eu chelate and UV-visible spectroscopy allows one to determine a luminophore/protein ratio equal to 3.2. Bio-affinity assays involving the recognition of a mucin-like protein expressed on human breast cancer MCF-7 cells by a biotinylated monoclonal antibody 5D10 to which EuB1 is attached via avidin-biotin coupling demonstrate that (i) avidin activity is little affected by the coupling reaction and (ii) detection limits obtained by time-resolved (TR) luminescence with EuB1 and a commercial Eu-avidin conjugate are one order of magnitude lower than those of an organic conjugate (FITC-streptavidin). In the second part of the paper, conditions for growing MCF-7 cells in 100-200 microm wide microchannels engraved in PDMS are established; we demonstrate that EuB1 can be applied as effectively on this lab-on-a-chip device for the detection of tumour-associated antigens as on MCF-7 cells grown in normal culture vials. In order to exploit the versatility of the ligand used for self-assembling [Ln(2)(L(C2(CO(2)H)))(3)] helicates, which sensitizes the luminescence of both Eu(III) and Tb(III) ions, a dual on-chip assay is proposed in which estrogen receptors (ERs) and human epidermal growth factor receptors (Her2/neu) can be simultaneously detected on human breast cancer tissue sections. The Ln helicates are coupled to two secondary antibodies: ERs are visualized by red-emitting EuB4 using goat anti-mouse IgG and Her2/neu receptors by green-emitting TbB5 using goat anti-rabbit IgG. The fact that the assay is more than 6 times faster and requires 5 times less reactants than conventional immunohistochemical assays provides essential advantages over conventional immunohistochemistry for future clinical biomarker detection.

Bioactive endophytic fungi isolated from Caesalpinia echinata Lam. (Brazilwood) and identification of beauvericin as a trypanocidal metabolite from Fusarium sp.

Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL), Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from Fusarium sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular culture assay.

Estrogenic activity assessment of environmental chemicals using in vitro assays: identification of two new estrogenic compounds.

Environmental chemicals with estrogenic activities have been suggested to be associated with deleterious effects in animals and humans. To characterize estrogenic chemicals and their mechanisms of action, we established in vitro and cell culture assays that detect human estrogen receptor [alpha] (hER[alpha])-mediated estrogenicity. First, we assayed chemicals to determine their ability to modulate direct interaction between the hER[alpha] and the steroid receptor coactivator-1 (SRC-1) and in a competition binding assay to displace 17ss-estradiol (E(2)). Second, we tested the chemicals for estrogen-associated transcriptional activity in the yeast estrogen screen and in the estrogen-responsive MCF-7 human breast cancer cell line. The chemicals investigated in this study were o,p'-DDT (racemic mixture and enantiomers), nonylphenol mixture (NPm), and two poorly analyzed compounds in the environment, namely, tris-4-(chlorophenyl)methane (Tris-H) and tris-4-(chlorophenyl)methanol (Tris-OH). In both yeast and MCF-7 cells, we determined estrogenic activity via the estrogen receptor (ER) for o,p'-DDT, NPm, and for the very first time, Tris-H and Tris-OH. However, unlike estrogens, none of these xenobiotics seemed to be able to induce ER/SRC-1 interactions, most likely because the conformation of the activated receptor would not allow direct contacts with this coactivator. However, these compounds were able to inhibit [(3)H]-E(2) binding to hER, which reveals a direct interaction with the receptor. In conclusion, the test compounds are estrogen mimics, but their molecular mechanism of action appears to be different from that of the natural hormone as revealed by the receptor/coactivator interaction analysis.