Analysis of molecular biology techniques for the diagnosis of human papillomavirus infection and cervical cancer prevention

The objective of the present study was to evaluate the usefulness of molecular methodologies to access human papillomavirus genome in the genital tract. Samples from 136 women aged 17 to 52 years old obtained from the Dr. Sérgio Franco Laboratories between 2000 and 2001, were analyzed by the hybrid capture assay and amplified by PCR with generic primers MY09/MY11 and specific primers for types 16, 18, 31, 33, 35, 58. Viral genome was detected in 71.3% of the samples by hybrid capture and 75% by amplification. When cytopathology was used as a reference method for screening lesions, hybrid capture (p=0) and amplification (p=0.002) presented positive association. The 3 methods showed absolute agreement when cytopathology confirmed papillomavirus infection and high grade intraepithelial lesion. Disagreements occurred for 10 cases: seven inflammatory cases positive by PCR and negative for hybrid capture and 3 low squamous intraepithelial lesions positive for hybrid capture but negative for amplification. In conclusion, hybrid capture was shown to be sensitive and specific enough for use in clinical routines. Moreover, the evaluation of viral load values obtained by this method were shown to be related to the severity of the lesion and merit further studies to analyze the possible association with risk of progression to malignancy.

High ffficiency transmission techniques for broadband wireless systems

Future broadband wireless systems are expected to cope with severely time dispersive channels, due to multi-path signal propagation between the transmitter and the receiver while having high power and spectral efficiency. Thus, advanced Frequency Domain Equalization techniques are required. The implementation complexity in mobile terminals should be as low as possible to achieve highest possible efficiency. Therefore, most of the signal processing requirements will be shifted to the base station and we will employ signals compatible with an efficient, grossly nonlinear power amplification. For this reason, we will consider offset modulation signals with quasi-constant envelope and develop receivers that will obtain good BER performance. However, these signals require a bandwidth significantly above the Nyquist rate, which can be reduced by an overlap of different frequency channels.

Human papillomavirus genotypes in asymptomatic young women from public schools in Rio de Janeiro, Brazil

INTRODUCTION: The aim of this work was to survey HPV information from a random population of young women from Rio de Janeiro, Brazil. METHODS: This cross-sectional study included cervical samples from 241 female students. To determine human papillomavirus status, polymerase chain reaction amplification was performed. HPV typing was determined by restriction fragment length polymorphism analysis. Demographic data, life style, sexual and gynecological history were obtained through use of a structured questionnaire. RESULTS: The average age of the women was 19.6 years-old (SD=3.4 years). HPV prevalence was 27.4%. Nineteen different HPV genotypes were detected, including 13 high risk types. HPV 16 was the most prevalent type (6.2%), followed by 31 (4.1 %) and 66 (3.7%). Most of the oncogenic types belonged to the A9 species (28/48). The frequency of women infected by at least one oncogenic type was significantly higher than those only infected by low risk types (18.7% versus 7.5%). Cervical changes were detected in 12.5% of the sample and were significantly linked to infection with HPV types of the A9 species. Demographic variables, sexual initiation, or number of sexual partners were not associated with HPV prevalence, variety of HPV genotypes or oncogenic types. CONCLUSIONS: The relative frequency of HPV genotypes other than vaccine types in young females should be taken into account when evaluating vaccination strategies. Due to the high prevalence of HPV infection among the population studied, implementation of sex education in schools, promotion of condom use and an organized screening program to prevent cervical cancer must be encouraged for this age group.

PCR-RFLP of 16S ribosomal DNA to confirm the identification of Enterococcus gallinarum and Enterococcus casseliflavus isolated from clinical and food samples

INTRODUCTION: This study aimed to confirm the identification of Enterococcus gallinarum and Enterococcus casseliflavus isolated from clinical and food samples by PCR-RFLP. METHODS: Fifty-two strains identified by conventional biochemical exams were submitted to PCR amplification and digested with HinfI. Only 20 (38.5%) of the 52 strains showed a DNA pattern expected for E. gallinarum and E. casseliflavus. RESULTS: Analysis of the results of this study showed that E. gallinarum and E. casseliflavus are occasionally erroneously identified and confirmed the potential application of 16S rDNA analysis for accurate identification of these species. CONCLUSIONS: A correct identification is important to distinguish between intrinsic and acquired vancomycin resistance.

Antimicrobial resistance and investigation of the molecular epidemiology of Listeria monocytogenes in dairy products

INTRODUCTION: Listeria monocytogenes is a ubiquitous microorganism in nature and is responsible for listeriosis, an infectious disease caused by consumption of contaminated food. METHODS: Molecular characterization was performed on 19 strains of Listeria monocytogenes (serovars 1/2a, 1/2b, 4b and 4c), isolated from dairy products in Rio Grande do Sul, Brazil. The molecular techniques applied were random amplification of polymorphic DNA and restriction enzyme analysis. In addition to the molecular analysis, the antimicrobial resistance profile was determined. RESULTS: The strains studied showed a low degree of diversity. In relation to the antimicrobial resistance profile of those microorganisms from the samples analyzed, all of them were susceptible to the antimicrobials tested. CONCLUSIONS: The molecular techniques that were used presented good discriminatory power for the strains studied. Furthermore, all of the samples that were analyzed were susceptible to the antimicrobials tested.