Evaluation of Bacteria and Fungi DNA Abundance in Human Tissues

Whereas targeted and shotgun sequencing approaches are both powerful in allowing the study of tissue-associated microbiota, the human: microorganism abundance ratios in tissues of interest will ultimately determine the most suitable sequencing approach. In addition, it is possible that the knowledge of the relative abundance of bacteria and fungi during a treatment course or in pathological conditions can be relevant in many medical conditions. Here, we present a qPCR-targeted approach to determine the absolute and relative amounts of bacteria and fungi and demonstrate their relative DNA abundance in nine different human tissue types for a total of 87 samples. In these tissues, fungi genomes are more abundant in stool and skin samples but have much lower levels in other tissues. Bacteria genomes prevail in stool, skin, oral swabs, saliva, and gastric fluids. These findings were confirmed by shotgun sequencing for stool and gastric fluids. This approach may contribute to a more comprehensive view of the human microbiota in targeted studies for assessing the abundance levels of microorganisms during disease treatment/progression and to indicate the most informative methods for studying microbial composition (shotgun versus targeted sequencing) for various samples types

Genomics and epidemiology for gastric adenocarcinomas (GE4GAC): a Brazilian initiative to study gastric cancer

Abstract Gastric cancer (GC) is the fifth most common type of cancer worldwide with high incidences in Asia, Central, and South American countries. This patchy distribution means that GC studies are neglected by large research centers from developed countries. The need for further understanding of this complex disease, including the local importance of epidemiological factors and the rich ancestral admixture found in Brazil, stimulated the implementation of the GE4GAC project. GE4GAC aims to embrace epidemiological, clinical, molecular and microbiological data from Brazilian controls and patients with malignant and pre-malignant gastric disease. In this letter, we summarize the main goals of the project, including subject and sample accrual and current findings

The Helicobacter pylori Genome Project : insights into H. pylori population structure from analysis of a worldwide collection of complete genomes

Helicobacter pylori, a dominant member of the gastric microbiota, shares co-evolutionary history with humans. This has led to the development of genetically distinct H. pylori subpopulations associated with the geographic origin of the host and with differential gastric disease risk. Here, we provide insights into H. pylori population structure as a part of the Helicobacter pylori Genome Project (HpGP), a multi-disciplinary initiative aimed at elucidating H. pylori pathogenesis and identifying new therapeutic targets. We collected 1011 well-characterized clinical strains from 50 countries and generated high-quality genome sequences. We analysed core genome diversity and population structure of the HpGP dataset and 255 worldwide reference genomes to outline the ancestral contribution to Eurasian, African, and American populations. We found evidence of substantial contribution of population hpNorthAsia and subpopulation hspUral in Northern European H. pylori. The genomes of H. pylori isolated from northern and southern Indigenous Americans differed in that bacteria isolated in northern Indigenous communities were more similar to North Asian H. pylori while the southern had higher relatedness to hpEastAsia. Notably, we also found a highly clonal yet geographically dispersed North American subpopulation, which is negative for the cag pathogenicity island, and present in 7% of sequenced US genomes. We expect the HpGP dataset and the corresponding strains to become a major asset for H. pylori genomics

NEUROLOGICAL DAMAGE IN PATIENTS IRRADIATED TWICE ON THE SPINAL-CORD - A MORPHOLOGIC AND ELECTROPHYSIOLOGICAL STUDY

We reviewed the files of 950 patients treated for Hodgkin's disease since 1966 and were able to find five patients treated with radiochemotherapy and irradiated twice on volumes including a cord segment, at various time intervals, and surviving until now. Seven patients with comparable clinical and therapeutic features, but not reirradiated on the cord, were chosen as a control group and were examined with the same diagnostic procedures. The cumulative cord dose in the reirradiated patients was recalculated and ranged from 50 to 70 Gy. All these patients and the control cases were followed up for more than 10 years and presented no or only minor neurological symptoms. We compare the results of both magnetic resonance imaging (MRI) and electrophysiological studies (spinal and scalp recorded somatosensory evoked potentials - SEPs) in an attempt to define the characteristics of the subclinical damage present in these patients. While no cord abnormality was demonstrated with MRI, electrophysiological studies evidenced a clear difference between cases and controls, as far as the D10-P1 conduction time and SEPs average amplitude are concerned. Advantages and drawbacks of a wide use of electrophysiological methods in research work on cord radiation damage are presented, along with the possible implications of the results obtained for the understanding of the pathogenesis and the dose dependence of radiation myelitis (RM)