The role of molecular imaging in modern drug development

Drug development represents a highly complex, inefficient and costly process. Over the past decade, the widespread use of nuclear imaging, owing to its functional and molecular nature, has proven to be a determinant in improving the efficiency in selecting the candidate drugs that should either be abandoned or moved forward into clinical trials. This helps not only with the development of safer and effective drugs but also with the shortening of time-to-market. The modern concept and future trends concerning molecular imaging will assumedly be hybrid or multimodality imaging, including combinations between high sensitivity and functional (molecular) modalities with high spatial resolution and morphological techniques.

Heavy-metal resistance in Marinobacter aquaeolei 617 insights into copper resistance

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Biotecnologia

Genetic variation between susceptible and non-susceptible snails to Schistosoma infection using random amplified polymorphic DNA analysis (RAPDs)

Susceptibility of snails to infection by certain trematodes and their suitability as hosts for continued development has been a bewildering problem in host-parasite relationships. The present work emphasizes our interest in snail genetics to determine what genes or gene products are specifically responsible for susceptibility of snails to infection. High molecular weight DNA was extracted from both susceptible and non-susceptible snails within the same species Biomphalaria tenagophila. RAPD was undertaken to distinguish between the two types of snails. Random primers (10 mers) were used to amplify the extracted DNA by the polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis (PAGE) and silver staining. The results suggest that RAPD represents an efficient means of genome comparison, since many molecular markers were detected as genetic variations between susceptible and non-susceptible snails.

Epidemiological analysis of bacterial strains involved in hospital infection in a University Hospital from Brazil

Hospital infections cause an increase in morbidity and mortality of hospitalized patients with significant rise in hospital costs. The aim of this work was an epidemiological analysis of hospital infection cases occurred in a public University Hospital in Rio de Janeiro. Hence, 238 strains were isolated from 14 different clinical materials of 166 patients hospitalized in the period between August 1995 and July 1997. The average age of the patients was 33.4 years, 72.9% used antimicrobials before having a positive culture. The most common risk conditions were surgery (19.3%), positive HIV or AIDS (18.1%) and lung disease (16.9%). 24 different bacterial species were identified, S. aureus (21%) and P. aeruginosa (18.5%) were predominant. Among 50 S. aureus isolated strains 36% were classified as MRSA (Methicillin Resistant S. aureus). The Gram negative bacteria presented high resistance to aminoglycosides and cephalosporins. A diarrhea outbreak, detected in high-risk neonatology ward, was caused by Salmonella serovar Infantis strain, with high antimicrobial resistance and a plasmid of high molecular weight (98Mda) containing virulence genes and positive for R factor.

Characterization of Nitric Oxide Reductase (NOR) from pseudomonas nautica, a study on biologic nitric oxide reduction

Dissertation submitted to obtain the phD degree in Biochemistry, specialty in Physical- Biochemistry, by the Faculdade de Ciências e Tecnologia from the Universidade Nova de Lisboa

Ditopic molecular architectures for the recognition of anionic species

Dissertation presented to obtain the Ph.D degree in Chemistry

Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro area, Brazil

A parasitological, clinical, serological and molecular cross-sectional study carried out in a highly endemic malaria area of Rio Negro in the Amazon State, Brazil, revealed a high prevalence of asymptomatic Plasmodium vivax infection. A total of 109 persons from 25 families were studied in five villages. Ninety-nine inhabitants (90.8%) had at least one previous episode of malaria. Serology showed 85.7% and 46.9% of positivity when P. falciparum antigens and P. vivax MSP-1, respectively, were used. Twenty blood samples were PCR positive for P. vivax (20.4%) and no P. falciparum infection was evidenced by this technique. No individual presenting positive PCR reaction had clinical malaria during the survey neither in the six months before nor after, confirming that they were cases of asymptomatic infection. Only one 12 year old girl presented a positive thick blood smear for P. vivax. This is the first description of asymptomatic Plasmodium infection in this area studied.

Molecular detection of HPV 16 and 18 in cervical samples of patients from Belo Horizonte, Minas Gerais, Brazil

PURPOSE: The aim of this study was to investigate the frequency of HPV infection and the types 16 and 18 in cervical samples from patients attended at two public health services of the city of Belo Horizonte, MG. METHODS: Cervical samples from 174 patients were collected for cytopathological and molecular tests. HPV infection was searched by PCR utilizing MY09 and MY11 primers or HPV 16 and HPV 18 specific primers. RESULTS: Amongst the 174 samples analyzed, 20.7% presented squamous intraepithelial and/or invasive lesions detected on cytopathological analysis and of those, 94.4% were infected by HPV. HPV 16 was found in 20% of the cases of low-grade squamous intraepithelial lesions and in 40% and 50% of high-grade squamous intraepithelial lesion and squamous invasive carcinoma, respectively. HPV 18 was detected in 6.7% of the low-grade lesion samples and in two HPV16 co-infected samples. In 50% of the cases of high-grade lesion, the HPV type was not determined. CONCLUSION: The HPV 16 was the virus type more frequently detected. However, more than 50% of the positive samples at the cytopathological analysis were negative for HPV 16 and 18, indicating that possibly other virus types are present in relative high frequencies in the studied population.

Primary Antiphospholipid Syndrome: Pregnancy Outcome in a Portuguese Population

Introduction:Women with antiphospholipid syndrome(APS) may suffer from recurrent miscarriage, fetal death, fetal growth restriction (FGR), pre-eclampsia, placental abruption, premature delivery and thrombosis. Treatment with aspirin and low molecular weight heparin (LMWH) combined with close maternal-fetal surveillance can change these outcomes. Objective: To assess maternal and perinatal outcome in a cohort of Portuguese women with primary APS. Patients and Methods: A retrospective analysis of 51 women with primary APS followed in our institution (January 1994 to December 2007). Forty one(80.4%) had past pregnancy morbidity and 35.3%(n=18) suffered previous thrombotic events. In their past they had a total of 116 pregnancies of which only 13.79 % resulted in live births. Forty four patients had positive anticardiolipin antibodies and 33 lupus anticoagulant. All women received treatment with low dose aspirin and LMWH. Results: There were a total of 67 gestations (66 single and one multiple). The live birth rate was 85.1%(57/67) with 10 pregnancy failures: seven in the first and second trimesters, one late fetal death and two medical terminations of pregnancy (one APS related). Mean (± SD) birth weight was 2837 ± 812 g and mean gestational age 37 ± 3.3 weeks. There were nine cases of FGR and 13 hypertensive complications(4 HELLP syndromes). 54.4% of the patients delivered by caesarean section. Conclusions: In our cohort, early treatment with aspirin and LMWH combined with close maternal-fetal surveillance was associated with a very high chance of a live newborn.

High prevalence and association of HIV-1 non-B subtype with specific sexual transmission risk among antiretroviral naïve patients in Porto Alegre, RS, Brazil

In South Brazil the circulation of two HIV-1 subtypes with different characteristics represents an important scenario for the study of the impact of HIV-1 diversity on the evolution of the HIV-1 epidemic and AIDS disease. HIV-1 B, the predominant variant in industrialized countries and HIV-1 C, the most prevalent subtype in areas with rapid epidemic growth, are implicated in most infections. We evaluated blood samples from 128 antiretroviral (ARV) naïve patients recruited at entry to the largest HIV outpatient service in Porto Alegre. Based on partial pol region sequencing, HIV-1 C was observed in 29%, HIV-1 B in 22.6% and, the recently identified CRF31_BC, in 23.4% of 128 volunteers. Other variants were HIV-1 F in 10% and other mosaics in 5.5%. In order to evaluate the association of socio-behavioral characteristics and HIV-1 subtypes, interviews and laboratory evaluation were performed at entry. Our data suggest an established epidemic of the three major variants, without any evidence of partitioning in either of the subgroups analyzed. However, anal sex practices were associated with subtype B, which could indicate a greater transmissibility of non-B variants by vaginal intercourse. This study provides baseline information for epidemiologic surveillance of the changes of the molecular characteristics of HIV-1 epidemics in this region.

The relationship of cardiorespiratory fitness, birth weight and parental BMI on adolescents’ obesity status

The aims of this study were as follows: (1) to analyze differences in cardiorespiratory fitness (CRF), parents' body mass index (BMI) and birth weight (BW) between non-overweight (NOW) and overweight/obese (OV/OB) adolescents, and (2) to investigate the association of those variables with the risk of their biological offspring being OV/OB. This study comprised 788 adolescents (477 girls and 311 boys), aged between 12 and 18 years. CRF was predicted by maximal multistage 20-m shuttle-run test according to the procedures described in FITNESSGRAM. Children's BMI was classified according to the International Obesity Task Force. Adolescents' BW was assessed from each child's pediatric record at birth. Parents' OV/OB status was defined and classified according to the World Health Organization. Socioeconomic status was defined by parental education. The prevalence OV/OB was 21.4 and 5.3%, respectively, and there were no gender differences. The OV/OB adolescents (girls and boys) had significantly (Phigher BW (Phigh BW (OR: 1.65; Phigh BW (OR: 2.09; Phighlight the association between the family adolescents' obesity, in girls. Furthermore, our data suggested that low CRF and high BW were strong predictors of OV/OB in adolescence.

Molecular characterization of Aeromonas spp. and Vibrio cholerae O1 isolated during a diarrhea outbreak

This work aimed to assess pathogenic potential and clonal relatedness of Aeromonas sp. and Vibrio cholerae isolates recovered during a diarrhea outbreak in Brazil. Clinical and environmental isolates were investigated for the presence of known pathogenic genes and clonal relatedness was assessed by intergenic spacer region (ISR) 16S-23S amplification. Four Aeromonas genes (lip, exu, gcat, flaA/B) were found at high overall frequency in both clinical and environmental isolates although the lip gene was specifically absent from selected species. A fifth gene, aerA, was rarely found in A. caviae, the most abundant species. The ISR profile revealed high heterogeneity among the Aeromonas isolates and no correlation with species identification. In contrast, in all the V. cholerae isolates the four genes investigated (ctxA, tcpA, zot and ace) were amplified and revealed homogeneous ISR and RAPD profiles. Although Aeromonas isolates were the major enteric pathogen recovered, their ISR profiles are not compatible with a unique cause for the diarrhea events, while the clonal relationship clearly implicates V. cholerae in those cases from which it was isolated. These results reinforce the need for a better definition of the role of aeromonads in diarrhea and whether they benefit from co-infection with V. cholerae.

Inferior Vena Cava Filter Placement During Pregnancy: an Adjuvant Option When Medical Therapy Fails

The authors present a case of a 27-year-old multiparous woman, with multiple thrombophilia, whose pregnancy was complicated with deep venous thrombosis requiring placement of a vena cava filter. At 15th week of gestation, following an acute deep venous thrombosis of the right inferior limb, anticoagulant therapy with low-molecular-weight heparin (LMWH) was instituted without improvement in her clinical status. Subsequently, at 18 weeks of pregnancy, LMWH was switched to warfarin. At 30th week of gestation, the maintenance of high thrombotic risk was the premise for placement of an inferior vena cava filter for prophylaxis of pulmonary embolism during childbirth and postpartum. There were no complications and a vaginal delivery was accomplished at 37 weeks of gestation. Venal placement of inferior vena cava filters is an attractive option as prophylaxis for pulmonary embolism during pregnancy.

MOLECULAR TYPING OF Candida albicans ISOLATES FROM HOSPITALIZED PATIENTS

SUMMARYIntroduction: The majority of nosocomial fungal infections are caused by Candida spp. where C. albicans is the species most commonly identified. Molecular methods are important tools for assessing the origin of the yeasts isolated in hospitals.Methods: This is a study on the genetic profifiles of 39 nosocomial clinical isolates of C. albicans using two typing methods: random amplifified polymorphic DNA (RAPD) and microsatellite, two different primers for each technique were used.Results: RAPD provided 10 and 11 different profiles with values for SAB of 0.84 ± 0.126 and 0.88 ± 0.08 for primers M2 and P4, respectively. Microsatellite using two markers, CDC3 and HIS3, allowed the observation of six and seven different alleles, respectively, with combined discriminatory power of 0.91.Conclusions: Although genetic variability is clear, it was possible to identify high similarity, suggesting a common origin for at least a part of isolates. It is important to emphasize that common origin was proven from yeasts isolated from colonization (urine, catheter or endotracheal secretions) and blood culture from the same patient, indicating that the candidemia must have started from a site of colonization. The combination of RAPD and microsatellite provides a quick and efficient analysis for investigation of similarity among nosocomial isolates of C. albicans.

FALSE-NEGATIVE DENGUE CASES IN RORAIMA, BRAZIL: AN APPROACH REGARDING THE HIGH NUMBER OF NEGATIVE RESULTS BY NS1 AG KITS

Serum samples from 150 NS1-negative (Platelia ELISA) patients presumptively diagnosed with dengue were analyzed by the TaqMan probed real-time reverse transcription PCR (TaqMan qRT-PCR) method. The qRT-PCR positive samples were tested for serotype by semi-nested RT-PCR and a qualitative immunochromatographic assay for IgG and IgM. Molecular detection methods showed 33 (22%) positive samples out of 150 NS1-antigen negative samples. Of these, 72% were collected up to day 2 after the onset of symptoms, when diagnostic sensitivity of NS1-antigen test assays is significantly enhanced. Most of the cases were not characterized as secondary infection. Twenty-eight samples were successfully serotyped, 75% of which for DENV-4, 14% for DENV-2, 7% for DENV-3 and 4% for DENV-1. These findings reaffirm the hyperendemic situation of the state of Roraima and suggest a lower sensitivity of the NS1 test, mainly when DENV-4 is the predominant serotype. Health care providers should therefore be aware of samples tested negative by NS1 antigen assays, especially when clinical symptoms and other laboratory data results show evidence of dengue infection.