Evaluating the latest high-throughput molecular techniques for the exploration of microbial gut communities

The human gut microbiota has become the subject of an increasing amount of attention, due to an emerging understanding of its role in maintaining health throughout our lives. Since only a small proportion of the gut bacteria can be quantified using traditional plate culturing methods, culture-independent approaches are required for determining the structure of complex microbial communities. To avoid cloning bias and low phylotype coverage that affects amplicon cloning and sequencing strategies, high-throughput methods such as phylogenetic arrays and massively parallel sequencing are now being used to find more than just the most abundant taxa, at significantly lower costs and higher speeds. The target for these methods is the 16S ribosomal RNA gene that is present in all prokaryotes. Since the gene is too long to be sequenced using high-throughput methods, regions of high variability (from V1-V9) are selected for amplification and either direct sequencing, or hybridization against phylogenetic microarrays. In our recent study,1 we compared sequencing of amplified V4 and V6 regions using 454 FLX Pyrosequencing2 with the HITChip, an oligonucleotide microarray for taxonomic profiling of human intestinal tract communities based on concatenations of known V1 and V6 regions.3 We found good correlations between the phylogenetic classifications stemming from the two technologies, especially at lower-order ranks (phylum, class, order, and to a lesser extent, family), which indicates high robustness of both approaches. However, the V6 regions proved to be much less suitable for taxonomic classification than the V4 region, probably due to this region simply being too variable. Although this study was, to our knowledge, the deepest sequencing of single gastrointestinal samples reported to date, the microbial richness levels had still not leveled out, with up to 1,800 unique phylotypes detected in one community. Encouragingly for studies with lower sequencing coverage per sample, we also noticed that a fifth of the sequencing depth (40,000 as opposed to 200,000 reads) was sufficient for capturing a majority of microbial diversity within a sample.     

Efficacy of a standardized technique of trans-vaginal entry into the peritoneal cavity for post-hysterectomy vaginal vault suspension

The aim of this paper is to describe the efficacy and safety of a standardized technique of trans-vaginal entry into the peritoneal cavity for post-hysterectomy vault prolapse and determine how well the pre-operative pelvic examination predicted successful peritoneal entry. A retrospective review of patients undergoing post-hysterectomy trans-vaginal apical suspensions using a standardized technique of peritoneal entry was employed in this study. A subset of patients underwent a standardized pre-operative evaluation to predict what organ was behind the vaginal cuff and posterior cul-de-sac. Peritoneal entry was attempted in 280 patients, and successfully achieved in 223(80%). One cystotomy and one proctotomy (0.3%) occurred during attempted entry. Of those who underwent the standardized pre-operative evaluation, peritoneal entry was successful 86% of the time when small bowel was predicted to lie behind the vaginal cuff or posterior cul-de-sac. Peritoneal entry can be safely achieved in the majority of post-hysterectomy prolapse patients. Pre-operative examination assists in predicting successful peritoneal entry.     

Hepatoblastoma presenting with focal nodular hyperplasia after treatment of neuroblastoma

Focal nodular hyperplasia (FNH) is a benign, poorly understood hepatic tumor that is rare in children. Although there is no evidence for malignant degeneration, FNH can occur adjacent to a malignancy. Here, the case of a 4-year-old boy with a hepatic mass and history of stage IV neuroblastoma is presented. Initial imaging and core-needle biopsy were consistent with FNH. However, after left lateral segmentectomy, pathologic examination revealed a malignant tumor most consistent with small cell undifferentiated hepatoblastoma as well as 3 foci of FNH in the surrounding parenchyma.     

Exploratory study examining barriers to participation in colorectal cancer screening

Objective:  To examine the Stage of Change distribution for bowel cancer screening in a regional Australian community and the factors associated with varying positions on the continuum of change.
Design:  Survey of a convenience sample.
Setting:  Community sample.
Participants:  A total of 59 (31 male, mean age  =  59) service club members from a South Australian regional community.
Main outcome measure:  Self-reported Stage of Change for bowel cancer screening behaviour.
Results:  Attributing greater embarrassment and discomfort to bowel cancer screening was associated with earlier positions on the Stages of Change. Perceiving that bowel cancer screening might have positive value for personal health was associated with more advanced positions on the continuum of change. Those who perceived breast and prostate screening procedures to be embarrassing or to cause discomfort were significantly less likely to be participating in bowel cancer screening. No significant relationships were found between bowel cancer screening Stage of Change and worry about vulnerability; personal, family or wider social network case reports of bowel cancer; and the population-level value attributed to the cancer screening procedures.
Conclusion:  Bowel cancer screening participation rates are currently lower than those associated with breast and prostate screening. Reducing perceptions of embarrassment and discomfort, increasing awareness of potential health benefits and maximising participation in other screening procedures might increase participation in bowel cancer screening.     

MRI thermometry: Fast mapping of RF‐induced heating along conductive wires

Conductive implants are in most cases a strict contraindication for MRI examinations, as RF pulses applied during the MRI measurement can lead to severe heating of the surrounding tissue. Understanding and mapping of these heating effects is therefore crucial for determining the circumstances under which patient examinations are safe. The use of fluoroptic probes is the standard procedure for monitoring these heating effects. However, the observed temperature increase is highly dependent on the positioning of such a probe, as it can only determine the temperature locally. Temperature mapping with MRI after RF heating can be used, but cooling effects during imaging lead to a significant underestimation of the heating effect. In this work, an MRI thermometry method was combined with an MRI heating sequence, allowing for temperature mapping during RF heating. This technique may provide new opportunities for implant safety investigations. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.     

Metarrhizium anisopliae as a Cause of Sinusitis in Immunocompetent Hosts

Metarrhizium anisopliae is a common pathogen of insects and has even been used to control insect populations. It is rarely isolated from human or animal sources, but recently, there have been three reported cases of disease, two in humans and one in a cat. We present our experience with five isolates from human sources, including two that were the apparent causes of two cases of sinusitis in immunocompetent hosts. The first patient was a 36-year-old male with frontal and ethmoid sinusitis, and the second was a 79-year-old female with chronic sinusitis. Both patients underwent surgery, and pathology of the surgical specimens revealed branching hyphae. Cultures grew only Metarrhizium species. Neither patient received antifungal therapy, and both did well postoperatively. The other three isolates were cultured from bronchoalveolar lavage specimens but were not felt to be clinically significant. Antifungal susceptibility testing using the National Committee for Clinical Laboratory Standards macrobroth method revealed that all isolates were resistant to amphotericin B, 5-flucytosine, and fluconazole. Itraconazole and newer azole compounds were more active. Metarrhizium species may cause disease in humans, even those without evidence of immunosuppression, and are apparently highly resistant to amphotericin B in vitro.