Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients

Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy (n = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples (n = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity (P < 0.01) and relative abundance of bacteria of the Ruminococcaceae family (P < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors.

Venocclusive disease of the liver after bone marrow transplantation: diagnosis, incidence, and predisposing factors

Venocclusive disease (VOD) of the liver, a fibrous obliteration of small hepatic venules, can be caused by chemoradiation therapy. We reviewed 255 consecutive patients undergoing bone marrow transplantation for malignancy during 1978 to 1980 in order to determine the incidence of VOD and the predisposing factors. Fifty-three of 255 patients met our criteria for VOD, for an incidence of 21%. Multivariate analysis showed that the most significant risk factors for VOD were age over 15, an underlying malignancy other than acute lymphocytic leukemia and hepatitis prior to transplantation. Patients with hepatitis had a 3.4-fold risk of developing VOD, as compared to patients with normal SGOT values (p = 0.0004). Hepatitis in this setting is probably of non-A, non-B viral etiology and represents a relative contraindication to marrow transplantation because of enhanced toxicity from conditioning chemoradiotherapy.

Mutations in sarcomere protein genes as a cause of dilated cardiomyopathy

BACKGROUND

The molecular basis of idiopathic dilated cardiomyopathy, a primary myocardial disorder that results in reduced contractile function, is largely unknown. Some cases of familial dilated cardiomyopathy are caused by mutations in cardiac cytoskeletal proteins; this finding implicates defects in contractile-force transmission as one mechanism underlying this disorder. To elucidate this important cause of heart failure, we investigated other genetic causes of dilated cardiomyopathy.

METHODS

Clinical evaluations were performed in 21 kindreds with familial dilated cardiomyopathy. A genome-wide linkage study prompted a search of the genes encoding beta-myosin heavy chain, troponin T, troponin I, and alpha-tropomyosin for disease-causing mutations.

RESULTS

A genetic locus for mutations associated with dilated cardiomyopathy was identified at chromosome 14q11.2-13 (maximal lod score, 5.11; theta=0), where the gene for cardiac beta-myosin heavy chain is encoded. Analyses of this and other genes for sarcomere proteins identified disease-causing dominant mutations in four kindreds. Cardiac beta-myosin heavy-chain missense mutations (Ser532Pro and Phe764Leu) and a deletion in cardiac troponin T (deltaLys210) caused early-onset ventricular dilatation (average age at diagnosis, 24 years) and diminished contractile function and frequently resulted in heart failure. Affected persons had neither antecedent cardiac hypertrophy (average maximal left-ventricular-wall thickness, 8.5 mm) nor histopathological findings characteristic of hypertrophy.

CONCLUSION

Mutations in sarcomere protein genes account for approximately 10 percent of cases of familial dilated cardiomyopathy and are particularly prevalent in families with early-onset ventricular dilatation and dysfunction. Because distinct mutations in sarcomere proteins cause either dilated or hypertrophic cardiomyopathy, the effects of mutant sarcomere proteins on muscle mechanics must trigger two different series of events that remodel the heart.

SIRPA is a specific cell-surface marker for isolating cardiomyocytes derived from human pluripotent stem cells

To identify cell-surface markers specific to human cardiomyocytes, we screened cardiovascular cell populations derived from human embryonic stem cells (hESCs) against a panel of 370 known CD antibodies. This screen identified the signal-regulatory protein alpha (SIRPA) as a marker expressed specifically on cardiomyocytes derived from hESCs and human induced pluripotent stem cells (hiPSCs), and PECAM, THY1, PDGFRB and ITGA1 as markers of the nonmyocyte population. Cell sorting with an antibody against SIRPA allowed for the enrichment of cardiac precursors and cardiomyocytes from hESC/hiPSC differentiation cultures, yielding populations of up to 98% cardiac troponin T-positive cells. When plated in culture, SIRPA-positive cells were contracting and could be maintained over extended periods of time. These findings provide a simple method for isolating populations of cardiomyocytes from human pluripotent stem cell cultures, and thereby establish a readily adaptable technology for generating large numbers of enriched cardiomyocytes for therapeutic applications.

Circular intermediates of recombinant adeno-associated virus have defined structural characteristics responsible for long-term episomal persistence in muscle tissue

Adeno-associated viral (AAV) vectors have demonstrated great utility for long-term gene expression in muscle tissue. However, the mechanisms by which recombinant AAV (rAAV) genomes persist in muscle tissue remain unclear. Using a recombinant shuttle vector, we have demonstrated that circularized rAAV intermediates impart episomal persistence to rAAV genomes in muscle tissue. The majority of circular intermediates had a consistent head-to-tail configuration consisting of monomer genomes which slowly converted to large multimers of >12 kbp by 80 days postinfection. Importantly, long-term transgene expression was associated with prolonged (80-day) episomal persistence of these circular intermediates. Structural features of these circular intermediates responsible for increased persistence included a DNA element encompassing two viral inverted terminal repeats (ITRs) in a head-to-tail orientation, which confers a 10-fold increase in the stability of DNA following incorporation into plasmid-based vectors and transfection into HeLa cells. These studies suggest that certain structural characteristics of AAV circular intermediates may explain long-term episomal persistence with this vector. Such information may also aid in the development of nonviral gene delivery systems with increased efficiency.

Microbial and Enzymatic Degradation of Synthetic Plastics

Synthetic plastics are pivotal in our current lifestyle and therefore, its accumulation is a major concern for environment and human health. Petroleum-derived (petro-)polymers such as polyethylene (PE), polyethylene terephthalate (PET), polyurethane (PU), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC) are extremely recalcitrant to natural biodegradation pathways. Some microorganisms with the ability to degrade petro-polymers under in vitro conditions have been isolated and characterized. In some cases, the enzymes expressed by these microbes have been cloned and sequenced. The rate of polymer biodegradation depends on several factors including chemical structures, molecular weights, and degrees of crystallinity. Polymers are large molecules having both regular crystals (crystalline region) and irregular groups (amorphous region), where the latter provides polymers with flexibility. Highly crystalline polymers like polyethylene (95%), are rigid with a low capacity to resist impacts. PET-based plastics possess a high degree of crystallinity (30-50%), which is one of the principal reasons for their low rate of microbial degradation, which is projected to take more than 50 years for complete degraded in the natural environment, and hundreds of years if discarded into the oceans, due to their lower temperature and oxygen availability. The enzymatic degradation occurs in two stages: adsorption of enzymes on the polymer surface, followed by hydro-peroxidation/hydrolysis of the bonds. The sources of plastic-degrading enzymes can be found in microorganisms from various environments as well as digestive intestine of some invertebrates. Microbial and enzymatic degradation of waste petro-plastics is a promising strategy for depolymerization of waste petro-plastics into polymer monomers for recycling, or to covert waste plastics into higher value bioproducts, such as biodegradable polymers via mineralization. The objective of this review is to outline the advances made in the microbial degradation of synthetic plastics and, overview the enzymes involved in biodegradation.

Efficacy and safety of endoscopic resection of large colorectal polyps: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of endoscopic resection of large colorectal polyps.

DESIGN

Relevant publications were identified in MEDLINE/EMBASE/Cochrane Central Register for the period 1966-2014. Studies in which ≥20 mm colorectal neoplastic lesions were treated with endoscopic resection were included. Rates of postendoscopic resection surgery due to non-curative resection or adverse events, as well as the rates of complete endoscopic removal, invasive cancer, adverse events, recurrence and mortality, were extracted. Study quality was ascertained according to Newcastle-Ottawa Scale. Forest plot was produced based on random effect models. I2 statistic was used to describe the variation across studies due to heterogeneity. Meta-regression analysis was also performed.

RESULTS

50 studies including 6442 patients and 6779 large polyps were included in the analyses. Overall, 503 out of 6442 patients (pooled rate: 8%, 95% CI 7% to 10%, I2=78.6%) underwent surgery due to non-curative endoscopic resection, and 31/6442 (pooled rate: 1%, 95% CI 0.7% to 1.4%, I2=0%) to adverse events. Invasive cancer at histology, non-curative endoscopic resection, synchronous lesions and recurrence accounted for 58%, 28%, 2.2% and 5.9% of all the surgeries, respectively. Endoscopic perforation occurred in 96/6595 (1.5%, 95% CI 1.2% to 1.7%) polyps, while bleeding in 423/6474 (6.5%, 95% CI 5.9% to 7.1%). Overall, 5334 patients entered in surveillance, 502/5836 (8.6%, 95% CI 7.9% to 9.3%) being lost at follow-up. Endoscopic recurrence was detected in 735/5334 patients (13.8%, 95% CI 12.9% to 14.7%), being an invasive cancer in 14/5334 (0.3%, 95% CI 0.1% to 0.4%). Endoscopic treatment was successful in 664/735 cases (90.3%, 95% CI 88.2% to 92.5%). Mortality related with management of large polyps was reported in 5/6278 cases (0.08%, 95% CI 0.01% to 0.15%).

CONCLUSIONS

Endoscopic resection of large polyps appeared to be an extremely effective and safe intervention. However, an adequate endoscopic surveillance is necessary for its long-term efficacy.

Effects of poststroke pyrexia on stroke outcome : a meta-analysis of studies in patients

BACKGROUND AND PURPOSE

The effect of pyrexia on cerebral ischemia has been extensively studied in animals. In humans, however, such studies are small and the results conflicting. We undertook a meta-analysis using all such published studies on the effect of hyperthermia on stroke outcome.

METHODS

Three databases were searched for all published studies that examined the relationship of raised temperature after stroke onset and eventual outcome. Combined probability values and odds ratios were obtained. A heterogeneity test was performed to ensure that the data were suitable for such an analysis. Morbidity and mortality were used as outcome measures.

RESULTS

Nine studies were identified totaling 3790 patients, providing our study with 99% power to detect a 9% increase in morbidity and 84% power to detect a 1% increase in mortality for the pyrexial group. The combined odds ratio for mortality was 1.19 (95% CI, 0.99 to 1.43). A heterogeneity test was highly nonsignificant (P>0.05) for mortality, suggesting that the data were sufficiently similar to be meta-analyzed. Combined probability values were highly significant for both morbidity (P<0.0001) and mortality (P<0. 00000001).

CONCLUSIONS

The results from this meta-analysis suggest that pyrexia after stroke onset is associated with a marked increase in morbidity and mortality. Measures should be taken to combat fever in the clinical setting to prevent stroke progression. The possible benefit of therapeutic hypothermia in the management of acute stroke should be further investigated.

Escherichia coli biofilm: development and therapeutic strategies

Escherichia coli biofilm consists of a bacterial colony embedded in a matrix of extracellular polymeric substances (EPS) which protects the microbes from adverse environmental conditions and results in infection. Besides being the major causative agent for recurrent urinary tract infections, E. coli biofilm is also responsible for indwelling medical device-related infectivity. The cell-to-cell communication within the biofilm occurs due to quorum sensors that can modulate the key biochemical players enabling the bacteria to proliferate and intensify the resultant infections. The diversity in structural components of biofilm gets compounded due to the development of antibiotic resistance, hampering its eradication. Conventionally used antimicrobial agents have a restricted range of cellular targets and limited efficacy on biofilms. This emphasizes the need to explore the alternate therapeuticals like anti-adhesion compounds, phytochemicals, nanomaterials for effective drug delivery to restrict the growth of biofilm. The current review focuses on various aspects of E. coli biofilm development and the possible therapeutic approaches for prevention and treatment of biofilm-related infections.

Survival benefit-based deceased-donor liver allocation

Currently, patients awaiting deceased-donor liver transplantation are prioritized by medical urgency. Specifically, wait-listed chronic liver failure patients are sequenced in decreasing order of Model for End-stage Liver Disease (MELD) score. To maximize lifetime gained through liver transplantation, posttransplant survival should be considered in prioritizing liver waiting list candidates. We evaluate a survival benefit based system for allocating deceased-donor livers to chronic liver failure patients. Under the proposed system, at the time of offer, the transplant survival benefit score would be computed for each patient active on the waiting list. The proposed score is based on the difference in 5-year mean lifetime (with vs. without a liver transplant) and accounts for patient and donor characteristics. The rank correlation between benefit score and MELD score is 0.67. There is great overlap in the distribution of benefit scores across MELD categories, since waiting list mortality is significantly affected by several factors. Simulation results indicate that over 2000 life-years would be saved per year if benefit-based allocation was implemented. The shortage of donor livers increases the need to maximize the life-saving capacity of procured livers. Allocation of deceased-donor livers to chronic liver failure patients would be improved by prioritizing patients by transplant survival benefit.

Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer

BACKGROUND

The randomized, double-blind OlympiA trial compared 1 year of the oral poly(adenosine diphosphate-ribose) polymerase inhibitor, olaparib, to matching placebo as adjuvant therapy for patients with pathogenic or likely pathogenic variants in germline BRCA1 or BRCA2 (gBRCA1/2pv) and high-risk, human epidermal growth factor receptor 2-negative, early breast cancer (EBC). The first pre-specified interim analysis (IA) previously demonstrated statistically significant improvement in invasive disease-free survival (IDFS) and distant disease-free survival (DDFS). The olaparib group had fewer deaths than the placebo group, but the difference did not reach statistical significance for overall survival (OS). We now report the pre-specified second IA of OS with updates of IDFS, DDFS, and safety.

PATIENTS AND METHODS

One thousand eight hundred and thirty-six patients were randomly assigned to olaparib or placebo following (neo)adjuvant chemotherapy, surgery, and radiation therapy if indicated. Endocrine therapy was given concurrently with study medication for hormone receptor-positive cancers. Statistical significance for OS at this IA required P < 0.015.

RESULTS

With a median follow-up of 3.5 years, the second IA of OS demonstrated significant improvement in the olaparib group relative to the placebo group [hazard ratio 0.68; 98.5% confidence interval (CI) 0.47-0.97; P = 0.009]. Four-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (Δ 3.4%, 95% CI -0.1% to 6.8%). Four-year IDFS for the olaparib group versus placebo group was 82.7% versus 75.4% (Δ 7.3%, 95% CI 3.0% to 11.5%) and 4-year DDFS was 86.5% versus 79.1% (Δ 7.4%, 95% CI 3.6% to 11.3%), respectively. Subset analyses for OS, IDFS, and DDFS demonstrated benefit across major subgroups. No new safety signals were identified including no new cases of acute myeloid leukemia or myelodysplastic syndrome.

CONCLUSION

With 3.5 years of median follow-up, OlympiA demonstrates statistically significant improvement in OS with adjuvant olaparib compared with placebo for gBRCA1/2pv-associated EBC and maintained improvements in the previously reported, statistically significant endpoints of IDFS and DDFS with no new safety signals.

Magnification chromoendoscopy for the detection of intestinal metaplasia and dysplasia in Barrett's oesophagus

BACKGROUND

The presence of intestinal metaplasia (IM) in the columnar lined distal oesophagus defines Barrett's oesophagus with the risk of future malignant transformation. The distribution of both IM and dysplasia (low grade (LGD) and high grade (HGD)) within the columnar lined oesophagus is patchy and mosaic requiring random biopsies. Techniques that could help target areas of high yield within Barrett's mucosa would be helpful.

AIM

To study the utility of high magnification chromoendoscopy (MCE) in the detection of IM, LGD, and HGD in patients with Barrett's oesophagus.

METHODS

Consecutive patients detected with columnar mucosa in the distal oesophagus were studied using an Olympus magnification endoscope (GIF-Q16OZ, 115x). The distal oesophagus was sprayed with indigo carmine solution and the oesophageal columnar mucosa patterns were noted under high magnification and targeted for biopsy. All biopsies were read by pathologists blinded to the endoscopic findings.

RESULTS

Eighty patients with suspected Barrett's oesophagus (that is, columnar lined distal oesophagus) were studied: mean age 62.7 years (range 35-81). Mean length of columnar mucosa was 3.7 cm (range 0.5-17). Three types of mucosal patterns were noted within the columnar mucosa after spraying indigo carmine and using MCE: ridged/villous pattern, circular pattern, and irregular/distorted pattern. The yield of IM on target biopsies according to the patterns was: ridged/villous 57/62 (97%) and circular 2/12 (17%). Six patients had an irregular/distorted pattern and all had HGD on biopsy (6/6 (100%)). Eighteen patients had LGD on target biopsies; all had the ridged/villous pattern. All patients with long segment Barrett's were identified using MCE whereas 23/28 patients (82%) with short segment Barrett's had the ridged/villous pattern.

CONCLUSIONS

MCE helps visually identify areas with IM and HGD having specific patterns but not patients with LGD (appear similar to IM). MCE may be a useful clinical tool for the increased detection of patients with IM as well as for surveillance of patients for the detection of HGD. If these preliminary results are validated, MCE would help identify high yield areas, potentially eliminating the need for random biopsies.

Miami classification for probe-based confocal laser endomicroscopy

An essential element for any new advanced imaging technology is standardization of indications, terminology, categorization of images, and research priorities. In this review, we propose a state-of-the-art classification system for normal and pathological states in gastrointestinal disease using probe-based confocal laser endomicroscopy (pCLE). The Miami classification system is based on a consensus of pCLE users reached during a meeting held in Miami, Florida, in February 2009.

Long-term follow-up of Barrett's high-grade dysplasia

OBJECTIVE

The management of Barrett's high-grade dysplasia (HGD) remains controversial. The aims of this study were to evaluate prospectively the outcome of unifocal HGD (uHGD) in patients with Barrett's esophagus, and to determine demographic and endoscopic features predictive of progression to multifocal HGD (mHGD) and/or adenocarcinoma.

METHODS

Consecutive Barrett's patients in whom uHGD was found at initial endoscopy or during surveillance underwent intensification of medical treatment and repeat endoscopy. The study endpoint was progression to mHGD or adenocarcinoma or HGD in conjunction with a dysplasia-associated lesion or mass (DALM). HGD diagnosis was confirmed by a second, blinded pathologist.

RESULTS

A total of 15 Barrett's patients with uHGD met inclusion criteria and have been prospectively followed for a mean +/- SD of 36.8 +/- 23.2 months. All were white and male, with a mean age +/- SD of 61.4 +/- 14.9 yr. Barrett's length varied from 1 to 13 cm (mean, +/- SD, 6.8 +/- 4 cm). Overall, eight (53.3%) uHGD progressed: four of 15 (26.7%) to frank cancer between 17 and 35 months of follow-up, two of 15 (13.3%) to mHGD with DALM in conjunction with one or more foci of possible intramucosal cancer after 12-91 months of follow-up, one of 15 (6.7%) to mHGD with a focus of possible intramucosal cancer after 14 months, and one of 15 (6.7%) to mHGD after 29 months. Seven of 15 (46.7%) uHGD have regressed, five to no dysplasia and two to LGD, over the course of follow-up ranging from 24 to 73 months (mean +/- SD, 43.3 +/- 19.9). All three patients with short-segment Barrett's esophagus with uHGD regressed. Fisher's exact test revealed that Barrett's length > or =3 cm and presence of hiatal hernia approached significance (p < 0.08) in predicting uHGD progression to mHGD/DALM/cancer. However, use of the log-rank test to account for differences in length of follow-up show no significance for hiatal hernia or Barrett's length.

CONCLUSIONS

Barrett's uHGD has a high risk for progressing to mHGD or cancer. Justification of an observational approach to uHGD should be discouraged. Markers of uHGD progression, as well as regression, are needed.

Short segment Barrett's esophagus--the need for standardization of the definition and of endoscopic criteria

There has been a recent increase in abstracts and publications reporting intestinal metaplasia in the distal esophagus and cardia. The terms "short segment Barrett's esophagus," "intestinal metaplasia of the esophagogastric junction," and "intestinal metaplasia of the cardia" are being used to describe either similar or different entities. This review article deals with the current data on these issues, the definition of short segment Barrett's esophagus including the endoscopic and histologic criteria, the rationale for separating short segment Barrett's esophagus from intestinal metaplasia of the cardia, and a simple classification of intestinal metaplasia.

p53 protein overexpression in low grade dysplasia (LGD) in Barrett's esophagus: immunohistochemical marker predictive of progression

OBJECTIVES

The presence of low grade dysplasia (LGD) within Barrett's esophagus (BE) has a multitude of ramifications. Identification of markers that could risk stratify LGD would be of great clinical benefit. We aimed to prospectively evaluate the prognosis of the immunohistochemical overexpression of p53 protein in BE colocalized to LGD.

METHODS

Consecutive BE patients in whom LGD was found had a repeat esophagogastroduodenoscopy within 8-12 wk per an ongoing prospective study. At each esophagogastroduodenoscopy, a therapeutic scope was used in conjunction with the Seattle Biopsy Protocol. Patients were observed until development of multifocal high grade dysplasia (mHGD), presence of an HGD dysplasia-associated lesion or mass (DALM) lesion, or frank adenocarcinoma. p53 protein overexpression was determined by computerized immunoquantitation using image analysis software on step serial-sectioned specimens of BE segment(s) harboring LGD. Kaplan-Meier survival curves were made on the ability of p53 staining colocalized to areas of LGD to predict progression to mHGD, HGD DALM, or cancer during prospective follow-up.

RESULTS

Forty-eight BE patients with LGD were observed for a mean of 41.2+/-22.5 months. During this period, five of 48 patients progressed to mHGD with a focus in which intramucosal cancer could not be excluded (one), mHGD/DALM with one or more foci in which intramucosal cancer could not be excluded (two), cancer (one), or mHGD (one). Twelve had persistent LGD and 31 had regressed to no dysplasia. p53 staining was positive and colocalized to areas of LGD in 4/31 of patients that regressed, 3/12 that persisted, and 3/5 that progressed. Kaplan-Meier curves differed significantly between p53 positive and negative patients for outcome defined as progression of LGD.

CONCLUSIONS

p53 colocalization with LGD at index LGD diagnosis is a risk factor for progression of LGD. This can potentially be used to risk stratify BE LGD patients in terms of surveillance intervals or enrollment into secondary prevention studies.

Analysis of different approaches for evaluation of surface energy of microbial cells by contact angle goniometry

Microbial adhesion on solid substrate is important in various fields of science. Mineral-microbe interactions alter the surface chemistry of the minerals and the adhesion of the bacterial cells to mineral surface is a prerequisite in several biobeneficiation processes. Apart from the surface charge and hydrophobic or hydrophilic character of the bacterial cells, the surface energy is a very important parameter influencing their adhesion on solid surfaces. There were many thermodynamic approaches in the literature to evaluate the cells surface energy. Although contact angle measurements with different liquids with known surface tension forms the basis in the calculation of the value of surface energy of solids, the results are different depending on the approach followed. In the present study, the surface energy of 140 bacterial and seven yeast cell surfaces has been studied following Fowkes, Equation of state, Geometric mean and Lifshitz-van der Waals acid-base (LW-AB) approaches. Two independent issues were addressed separately in our analysis. At first, the surface energy and the different components of the surface energy for microbial cells surface are examined. Secondly, the different approaches are evaluated for their internal consistency, similarities and dissimilarities. The Lifshitz-van der Waals component of surface energy for most of the microbial cells is realised to be approximately 40 mJ/m2 +/-10%. Equation of state and Geometric mean approaches do not possess any internal consistency and yield different results. The internal consistency of the LW-AB approach could be checked only by varying the apolar liquid and it evaluates coherent surface energy parameters by doing so. The electron-donor surface energy component remains exactly the same with the change of apolar liquid. This parameter could differentiate between the Gram-positive and Gram-negative bacterial cells. Gram-negative bacterial cells having higher electron-donor parameter had lower nitrogen, oxygen and phosphorous content on their cell surfaces. Among the four approaches, LW-AB was found to give the most consistent results. This approach provides more detailed information about the microbial cell surface and the electron-donor parameter differentiates different type of cell surfaces.

Cosmogenic Chlorine-36 Chronology for Glacial Deposits at Bloody Canyon, Eastern Sierra Nevada

Deposits from mountain glaciers provide an important record of Quaternary climatic fluctuations but have proved difficult to date directly. A chronology has been obtained for glacial deposits at Bloody Canyon, California, by measurement ofthe accumulation of chlorine-36 produced by cosmic rays in boulders exposed on moraine crests. The accumulation ofchlorine-36 indicates that episodes of glaciation occurred at about 21, 24, 65, 115, 145, and 200 ka (thousand years ago). Although the timing of the glaciations correlates well with peaks of global ice volume inferred from the marine oxygen isotope record, the relative magnitudes differ markedly. The lengths of the moraines dating from 115 ka and 65 ka show that the early glacial episodes were more extensive than those during the later Wisconsin and indicate that the transition from interglacial to full glacial conditions was rapid.

Relative risk of dysplasia for patients with intestinal metaplasia in the distal oesophagus and in the gastric cardia

BACKGROUND

Biopsy specimens obtained from the gastro-oesophageal junction can reveal intestinal metaplasia in patients presenting for routine upper endoscopy. The site of biopsy may play a critical role in determining the dysplasia risk of a patient.

AIMS

To evaluate prospectively the dysplasia risk in patients with intestinal metaplasia of the distal oesophagus or within the gastric cardia.

METHODS

Patients with short segment Barrett's oesophagus (SSBO) and cardia intestinal metaplasia (CIM) were followed prospectively.

RESULTS

177 patients with SSBO were identified (mean age 62 years, range 38-82; 91% whites). Twenty prevalence cases of dysplasia in SSBO were detected: 17 low grade dysplasia (LGD), three high grade dysplasia (HGD). Seventy six patients with CIM were identified (mean age 67 years, range 37-81; 81% whites). A single prevalence case of LGD in CIM was detected. During follow up of 78 SSBO and 34 CIM patients, dysplasia developed in nine (seven LGD, two HGD) with SSBO and in one (LGD) with CIM. There were significant differences between the two groups with respect to age, ethnicity, dysplasia prevalence, and incidence. Time to dysplasia progression was significantly longer in CIM compared with SSBO patients. Of the five patients with SSBO and HGD, one developed adenocarcinoma of the oesophagus on follow up. No HGD or cancers have been detected over this time period in CIM patients.

CONCLUSIONS

The dysplasia risk is significantly greater in SSBO than in CIM patients, indicating two potentially different clinical processes. Future studies should separate SSBO from CIM in order to enhance the understanding of the pathophysiology and malignant potential of each entity.

Isolation and characterization of a novel toluene-degrading, sulfate-reducing bacterium

A novel sulfate-reducing bacterium isolated from fuel-contaminated subsurface soil, strain PRTOL1, mineralizes toluene as the sole electron donor and carbon source under strictly anaerobic conditions. The mineralization of 80% of toluene carbon to CO2 was demonstrated in experiments with [ring-U-14C]toluene; 15% of toluene carbon was converted to biomass and nonvolatile metabolic by-products, primarily the former. The observed stoichiometric ratio of moles of sulfate consumed per mole of toluene consumed was consistent with the theoretical ratio for mineralization of toluene coupled with the reduction of sulfate to hydrogen sulfide. Strain PRTOL1 also transforms o- and p-xylene to metabolic products when grown with toluene. However, xylene transformation by PRTOL1 is slow relative to toluene degradation and cannot be sustained over time. Stable isotope-labeled substrates were used in conjunction with gas chromatography-mass spectrometry to investigate the by-products of toluene and xylene metabolism. The predominant by-products from toluene, o-xylene, and p-xylene were benzylsuccinic acid, (2-methylbenzyl)succinic acid, and 4-methylbenzoic acid (or p-toluic acid), respectively. Metabolic by-products accounted for nearly all of the o-xylene consumed. Enzyme assays indicated that acetyl coenzyme A oxidation proceeded via the carbon monoxide dehydrogenase pathway. Compared with the only other reported toluene-degrading, sulfate-reducing bacterium, strain PRTOL1 is distinct in that it has a novel 16S rRNA gene sequence and was derived from a freshwater rather than marine environment.

Gold nanoparticles as a contrast agent for in vivo tumor imaging with photoacoustic tomography

Photoacoustic tomography (PAT) is a rapidly emerging non-invasive imaging technology that integrates the merits of high optical contrast with high ultrasound resolution. The ability to quantitatively and non-invasively image nanoparticles has important implications for the development of nanoparticles as in vivo cancer diagnostic and therapeutic agents. In this study, the ability of systemically administered poly(ethylene glycol)-coated (PEGylated) gold nanoparticles as a contrast agent for in vivo tumor imaging with PAT has been evaluated. We demonstrate that gold nanoparticles (20 and 50 nm) have high photoacoustic contrast as compared to mouse tissue ex vivo. Gold nanoparticles can be visualized in mice in vivo following subcutaneous administration using PAT. Following intravenous administration of PEGylated gold nanoparticles to tumor-bearing mice, accumulation of gold nanoparticles in tumors can be effectively imaged with PAT. With gold nanoparticles as a contrast agent, PAT has important potential applications in the image guided therapy of superficial tumors such as breast cancer, melanoma and Merkel cell carcinoma.

Systematic review and economic modelling of the relative clinical benefit and cost-effectiveness of laparoscopic surgery and robotic surgery for removal of the prostate in men with localised prostate cancer

BACKGROUND

Complete surgical removal of the prostate, radical prostatectomy, is the most frequently used treatment option for men with localised prostate cancer. The use of laparoscopic (keyhole) and robot-assisted surgery has improved operative safety but the comparative effectiveness and cost-effectiveness of these options remains uncertain.

OBJECTIVE

This study aimed to determine the relative clinical effectiveness and cost-effectiveness of robotic radical prostatectomy compared with laparoscopic radical prostatectomy in the treatment of localised prostate cancer within the UK NHS.

DATA SOURCES

MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, BIOSIS, Science Citation Index and Cochrane Central Register of Controlled Trials were searched from January 1995 until October 2010 for primary studies. Conference abstracts from meetings of the European, American and British Urological Associations were also searched. Costs were obtained from NHS sources and the manufacturer of the robotic system. Economic model parameters and distributions not obtained in the systematic review were derived from other literature sources and an advisory expert panel.

REVIEW METHODS

Evidence was considered from randomised controlled trials (RCTs) and non-randomised comparative studies of men with clinically localised prostate cancer (cT1 or cT2); outcome measures included adverse events, cancer related, functional, patient driven and descriptors of care. Two reviewers abstracted data and assessed the risk of bias of the included studies. For meta-analyses, a Bayesian indirect mixed-treatment comparison was used. Cost-effectiveness was assessed using a discrete-event simulation model.

RESULTS

The searches identified 2722 potentially relevant titles and abstracts, from which 914 reports were selected for full-text eligibility screening. Of these, data were included from 19,064 patients across one RCT and 57 non-randomised comparative studies, with very few studies considered at low risk of bias. The results of this study, although associated with some uncertainty, demonstrated that the outcomes were generally better for robotic than for laparoscopic surgery for major adverse events such as blood transfusion and organ injury rates and for rate of failure to remove the cancer (positive margin) (odds ratio 0.69; 95% credible interval 0.51 to 0.96; probability outcome favours robotic prostatectomy = 0.987). The predicted probability of a positive margin was 17.6% following robotic prostatectomy compared with 23.6% for laparoscopic prostatectomy. Restriction of the meta-analysis to studies at low risk of bias did not change the direction of effect but did decrease the precision of the effect size. There was no evidence of differences in cancer-related, patient-driven or dysfunction outcomes. The results of the economic evaluation suggested that when the difference in positive margins is equivalent to the estimates in the meta-analysis of all included studies, robotic radical prostatectomy was on average associated with an incremental cost per quality-adjusted life-year that is less than threshold values typically adopted by the NHS (£30,000) and becomes further reduced when the surgical capacity is high.

LIMITATIONS

The main limitations were the quantity and quality of the data available on cancer-related outcomes and dysfunction.

CONCLUSIONS

This study demonstrated that robotic prostatectomy had lower perioperative morbidity and a reduced risk of a positive surgical margin compared with laparoscopic prostatectomy although there was considerable uncertainty. Robotic prostatectomy will always be more costly to the NHS because of the fixed capital and maintenance charges for the robotic system. Our modelling showed that this excess cost can be reduced if capital costs of equipment are minimised and by maintaining a high case volume for each robotic system of at least 100-150 procedures per year. This finding was primarily driven by a difference in positive margin rate. There is a need for further research to establish how positive margin rates impact on long-term outcomes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Esophageal infections in immunosuppressed patients after marrow transplantation

We reviewed all cases of infectious esophagitis diagnosed after marrow transplantation during a 2-yr period. Twenty-one infections were found during 46 fiberoptic endoscopic examinations; most infections were viral, with equal numbers due to cytomegalovirus and herpes simplex virus. These infections presented with nonspecific esophageal symptoms weeks to months after transplantation. Diagnoses depended on histology and viral cultures. During the same time span, autopsies revealed 25 cases of infective esophagitis among 59 patients; most were again viral, with equal numbers of herpes simplex virus and cytomegalovirus infections. Mixed infections due to viral, fungal, and bacterial pathogens were found in both endoscopy and autopsy series. The prevalence of esophageal infection in marrow transplant patients with esophageal symptoms is high, but the organisms could not be predicted on the basis of symptoms, oropharyngeal surveillance cultures, or esophageal x-ray. Accurate diagnosis requires that endoscopic biopsy specimens and brushings be examined by both histologic and virologic methods.

Mesoscale flux-closure domain formation in single-crystal BaTiO3

Over 60 years ago, Charles Kittel predicted that quadrant domains should spontaneously form in small ferromagnetic platelets. He expected that the direction of magnetization within each quadrant should lie parallel to the platelet surface, minimizing demagnetizing fields,and that magnetic moments should be configured into an overall closed loop, or flux-closure arrangement. Although now a ubiquitous observation in ferromagnets, obvious flux-closure patterns have been somewhat elusive in ferroelectric materials. This is despite the analogous behaviour between these two ferroic subgroups and the recent prediction of dipole closure states by atomistic simulations research. Here we show Piezoresponse Force Microscopy images of mesoscopic dipole closure patterns in free-standing, single-crystal lamellae of BaTiO3. Formation of these patterns is a dynamical process resulting from system relaxation after the BaTiO3 has been poled with a uniform electric field. The flux-closure states are composed of shape conserving 90° stripe domains which minimize disclination stresses.

Flux-closure patterns are rarely observed in ferroelectric materials and almost exclusively form at the nanoscale. McQuaid et al. report mesoscopic dipole closure patterns formed in free-standing single-crystal lamellae of BaTiO₃, thought to result from an unusual set of experimental conditions.

Early referral strategies for management of people with markers of renal disease: a systematic review of the evidence of clinical effectiveness, cost-effectiveness and economic analysis

BACKGROUND

Chronic kidney disease (CKD) is a long-term condition and has been described as the gradual loss of kidney function over time. Early in the disease process, people with CKD often experience no symptoms. For a long time, CKD has been an underdiagnosed condition. Even in the absence of symptoms, CKD appears to add significantly to the burden of cardiovascular disease and death and, for an important minority, can progress to kidney failure.

OBJECTIVE

To systematically review the evidence of the clinical effectiveness and cost-effectiveness of early referral strategies for management of people with markers of renal disease.

DATA SOURCES

Electronic searches of 12 major databases (such as MEDLINE, EMBASE, CINAHL, etc.) were conducted for the time period of 1990 to April 2008 to identify studies comparing early referral to other care options for people with CKD. Additional searching was performed in the NHS Economic Evaluation Database to support the cost-effectiveness literature review.

REVIEW METHODS

Two authors reviewed all titles, abstracts and full papers to select relevant literature. A Markov model was constructed to represent the natural history of CKD. The model allowed cohorts to be tracked according to estimated glomerular filtration rate (eGFR) status and the presence of other complications known to influence CKD progression and the incidence of cardiovascular events.

RESULTS

From 36 relevant natural history studies, CKD was found to be, despite marked heterogeneity between studies, a marker of increased risk of mortality, renal progression and end-stage renal disease. Mortality was generally high and increased with stage of CKD. After adjustment for comorbidities, the relative risk of mortality among those with CKD identified from the general population increased with stage. For clinical populations, the relative risk was higher. All three outcomes increased as eGFR fell. Only seven studies, and no randomised controlled trials, were identified as relevant to assessing the clinical effectiveness of early referral strategies for CKD. In the five retrospective studies constructed from cohorts starting on renal replacement therapy (RRT), mortality was reduced in the early referral group (more than 12 months prior to RRT) even as late as 5 years after initiation of RRT. Only two studies included predialysis participants. One study, in people screened for diabetic nephropathy, reported a reduction in the decline in renal function associated with early referral to nephrology specialists (eGFR decline 3.4 ml/min/1.73 m(2)) when compared with a similar group that had no access to nephrology services until dialysis was required (eGFR decline 12.0 ml/min/1.73 m(2)). The second study, among a group of veterans with two creatinine levels of at least 140 mg/dl, reported that a composite end point of death or progression was lower in the group receiving nephrology follow-up than in those receiving only primary care follow-up. The greatest effect was observed in those with stage 3 or worse disease after adjustment for comorbidities, age, race, smoking and proteinuria {stage 3: hazard ratio (HR) 0.8 [95% confidence interval (CI) 0.61 to 0.9)]; stage 4: HR 0.75 (95% CI 0.45 to 0.89)}. In the base-case analysis, all early referral strategies produced more quality-adjusted life-years (QALYs) than referral upon transit to stage 5 CKD (eGFR 15 ml/min/1.73 m(2)). Referral for everyone with an eGFR below 60 ml/min/1.73 m(2) (stage 3a CKD) generated the most QALYs and, compared with referral for stage 4 CKD (eGFR < 30 ml/min/1.73 m(2)), had an incremental cost-effectiveness ratio of approximately 3806 pounds per QALY.

LIMITATIONS

Because of a lack of data on the natural history of CKD in individuals without diabetes, and a lack of evidence on the costs and effects of early referral, the Markov model relied on many assumptions. The findings were particularly sensitive to changes in eGFR decline rates and the relative effect of early referral on CKD progression and cardiovascular events; the latter parameter being derived from a single non-randomised study.

CONCLUSIONS

Despite substantial focus on the early identification and proactive management of CKD in the last few years, we have identified significant evidence gaps about how best to manage people with CKD. There was some evidence to suggest that the care of people with CKD could be improved and, because these people are at risk from both renal and cardiovascular outcomes, strategies to improve the management of people with CKD have the potential to offer an efficient use of health service resources. Given the number of people now being recognised as having markers of kidney impairment, there is an urgent need for further research to support service change.