Standardization and statistical approaches to therapeutic trials in the R6/2 mouse

The R6/2 mouse is the most widely used animal model of Huntington's disease (HD), a genetic disorder causing movement disorders, personality changes, dementia, and premature death, for which there is currently no effective therapy. Use of animal models to assess novel therapeutic approaches to HD is currently a major focus of research. Progress in this field will depend upon careful standardization of experimental protocols, and a sophisticated statistical approach. Here we investigate the sources of phenotypic variability in R6/2, and make recommendations for the future use of such models in therapeutic trials.     

Legislative mandates for use of active surveillance cultures to screen for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci: position statement from the Joint SHEA and APIC Task Force.

Legislation aimed at controlling antimicrobial-resistant pathogens through the use of active surveillance cultures to screen hospitalized patients has been introduced in at least 2 US states. In response to the proposed legislation, the Society for Healthcare Epidemiology of America (SHEA) and the Association of Professionals in Infection Control and Epidemiology (APIC) have developed this joint position statement. Both organizations are dedicated to combating healthcare-associated infections with a wide array of methods, including the use of active surveillance cultures in appropriate circumstances. This position statement reviews the proposed legislation and the rationale for use of active surveillance cultures, examines the scientific evidence supporting the use of this strategy, and discusses a number of unresolved issues surrounding legislation mandating use of active surveillance cultures. The following 5 consensus points are offered. (1) Although reducing the burden of antimicrobial-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), is of preeminent importance, APIC and SHEA do not support legislation to mandate use of active surveillance cultures to screen for MRSA, VRE, or other antimicrobial-resistant pathogens. (2) SHEA and APIC support the continued development, validation, and application of efficacious and cost-effective strategies for the prevention of infections caused by MRSA, VRE, and other antimicrobial-resistant and antimicrobial-susceptible pathogens. (3) APIC and SHEA welcome efforts by healthcare consumers, together with private, local, state, and federal policy makers, to focus attention on and formulate solutions for the growing problem of antimicrobial resistance and healthcare-associated infections. (4) SHEA and APIC support ongoing additional research to determine and optimize the appropriateness, utility, feasibility, and cost-effectiveness of using active surveillance cultures to screen both lower-risk and high-risk populations. (5) APIC and SHEA support stronger collaboration between state and local public health authorities and institutional infection prevention and control experts.     

An unusual cause of diffuse pulmonary haemorrhage

Introduction: Diffuse pulmonary haemorrhage is a potentially life‐threatening complication of a variety of conditions. Tumours, including angiosarcoma lung metastases, are an unusual cause of pulmonary haemorrhage. Methods: Report of a case. Results: This case describes a 38‐year‐old previously healthy male who presented with chest wall bruising followed by haemoptysis and a cerebellar haemorrhage. The patient developed diffuse pulmonary haemorrhage. A biopsy of the chest wall lesion indicated a haematoma and an open‐lung biopsy suggested the diagnosis of vasculitis. The patient died within 3 months after initial presentation and an autopsy revealed a chest wall angiosarcoma with pulmonary and cerebellar metastases. Conclusion: Pulmonary angiosarcoma metastases should be included in the differential diagnosis of diffuse pulmonary haemorrhage, especially in a young, previously healthy patient with normal renal function, particularly as the pathological diagnosis may be difficult and even misleading. Please cite this paper as: Hui C. An unusual cause of diffuse pulmonary haemorrhage. The Clinical Respiratory Journal 2008; 2: 183–186.     

Fecal microbiome and metabolome differ in healthy and food-allergic twins

BACKGROUNDThere has been a striking generational increase in the prevalence of food allergies. We have proposed that this increase can be explained, in part, by alterations in the commensal microbiome.METHODSTo identify bacterial signatures and metabolic pathways that may influence the expression of this disease, we collected fecal samples from a unique, well-controlled cohort of twins concordant or discordant for food allergy. Samples were analyzed by integrating 16S rRNA gene amplicon sequencing and liquid chromatography–tandem mass spectrometry metabolite profiling.RESULTSA bacterial signature of 64 operational taxonomic units (OTUs) distinguished healthy from allergic twins; the OTUs enriched in the healthy twins were largely taxa from the Clostridia class. We detected significant enrichment in distinct metabolite pathways in each group. The enrichment of diacylglycerol in healthy twins is of particular interest for its potential as a readily measurable fecal biomarker of health. In addition, an integrated microbial-metabolomic analysis identified a significant association between healthy twins and Phascolarctobacterium faecium and Ruminococcus bromii, suggesting new possibilities for the development of live microbiome-modulating biotherapeutics.CONCLUSIONTwin pairs exhibited significant differences in their fecal microbiomes and metabolomes through adulthood, suggesting that the gut microbiota may play a protective role in patients with food allergies beyond the infant stage.TRIAL REGISTRATIONParticipants in this study were recruited as part of an observational study (ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01613885","term_id":"NCT01613885"}}NCT01613885) at multiple sites from 2014 to 2018.FUNDINGThis work was supported by the Sunshine Charitable Foundation; the Moss Family Foundation; the National Institute of Allergy and Infectious Diseases (NIAID) (R56AI134923 and R01AI 140134); the Sean N. Parker Center for Allergy and Asthma Research; the National Heart, Lung, and Blood Institute (R01 HL 118612); the Orsak family; the Kepner family; and the Stanford Institute for Immunity, Transplant and Infection.     

Assessment of the effect of ramipril therapy on direct health care costs for first and recurrent strokes in high-risk cardiovascular patients using data from the Heart Outcomes Prevention Evaluation (HOPE) study

BACKGROUND: In the Heart Outcomes Prevention Evaluation (HOPE) Study, the angiotensin-converting enzyme (ACE) inhibitor ramipril was shown to significantly reduce the relative risk of stroke by 32% in high-risk cardiovascular patients (P < 0.001). However, the study did not examine the economic implications of these findings. OBJECTIVE: The purpose of this economic analysis was to estimate the potential economic benefits of the differences in direct health care costs attributable to the prevention of first and recurrent strokes in the HOPE Study patient population through the use of ramipril. METHODS: The epidemiologic component of the model examined the incidence of first and recurrent strokes in the HOPE Study population, assessed at annual increments, for the years 1995 through 1997. An economic decision model was constructed by the application of costs to the epidemiologic foundation. Direct costs for stroke hospitalization and follow-up were calculated based on estimates provided by Samsa et al (1999). The estimated cost of ramipril treatment was based on the average wholesale price for the corresponding year of the analysis. The Samsa index costs are given in 1991 US $; they were converted to study-year US $ using the Consumer Price Index for the corresponding year. RESULTS: The mean age of the patient population was 69 years, with >70% of patients aged >/=65 years. When ACE-inhibitor treatment costs were included in the calculation of treatment costs, the expense to avert 1 stroke was estimated at $13,766 for years 1 to 2 after randomization and $12,281 for years 2 to 3. By years 3 to 4, ramipril treatment resulted in 21 fewer strokes and produced an estimated savings of $52,861. CONCLUSION: Ramipril 10 mg/d was a cost-effective means of preventing first and recurrent ischemic strokes in the HOPE Study patient population.     

Endotoxin priming exacerbates acute reflux pancreatitis in the rat

Recently, endotoxaemia has been reported as a prognostic marker in acute pancreatitis. However, the role of endotoxin in inducing or aggravating acute pancreatitis is not fully understood. We administered endotoxin 400 μg/kg i.p. to rats 24 h before performing either a closed duodenal loop (group B) or a sham operation (group D). Pancreatic damage and overall survival were compared with the results obtained in rats not exposed to endotoxin undergoing either closed duodenal loop (group A) or sham treatment (group C). In a first set of experiments, 24 h after laparotomy blood samples were collected and the animals were sacrificed; survival up to 8 days was estimated in a second set of experiments. Group B had higher lipase concentrations and more severe tissue damage than group C (P<0.05). A larger number of abscesses was observed in both group B and group D as compared to group C (P<0.05). Survival was significantly shorter in group B (P<0.0001). We conclude that priming with endotoxin worsens the extent of pancreatic damage induced by the closed duodenal loop procedure in the rat, possibly favouring selective homing of neutrophils to the site of inflammation, in similarity to what happens in the Shwartzman phenomenon.     

Chondrogenesis by bone marrow‐derived mesenchymal stem cells grown in chondrocyte‐conditioned medium for auricular reconstruction

Bone marrow‐derived mesenchymal stem cells (BMSCs) can be obtained by minimally invasive means and would be a favourable source for cell‐based cartilage regeneration. However, controlling the differentiation of the BMSCs towards the desired chondrogenic pathway has been a challenge hampering their application. The major aim of the present study was to determine if conditioned medium collected from cultured auricular chondrocytes could promote chondrogenic differentiation of BMSCs. Auricular chondrocytes were isolated and grown in BMSC standard culture medium (SM) that was collected and used as chondrocyte‐conditioned medium (CCM). The BMSCs were expanded in either CCM or SM for three passages. Cells were seeded onto fibrous collagen scaffolds and precultured for 2 weeks with or without transforming growth factor‐beta 3 (TGF‐β3). After preculture, constructs were implanted subcutaneously in nude mice for 6 and 12 weeks and evaluated with real‐time polymerase chain reaction, histology, immunohistochemistry and biochemistry. Real‐time polymerase chain reaction results showed upregulation of COL2A1 in the constructs cultured in CCM compared with those in SM. After 12 weeks in vivo, abundant neocartilage formation was observed in the implants that had been cultured in CCM, with or without TGF‐β3. In contrast, very little cartilage matrix formation was observed within the SM groups, regardless of the presence of TGF‐β3. Osteogenesis was only observed in the SM group with TGF‐β3. In conclusion, CCM even had a stronger influence on chondrogenesis than the supplementation of the standard culture medium with TGF‐β3, without signs of endochondral ossification. Efficient chondrogenic differentiation of BMSCs could provide a promising alternative cell population for auricular regeneration. Copyright © 2016 John Wiley & Sons, Ltd.     

Poly(glycerol sebacate)-engineered plugs to repair chronic tympanic membrane perforations in a chinchilla model

Objective

To evaluate the degree of neovascularization and efficacy of repair of chronic tympanic membrane perforations in a chinchilla model using poly(glycerol sebacate) (PGS), a novel bioengineered scaffold material.

Study Design

A feasibility study in which chinchilla ears with chronic perforations were randomly assigned to repair with PGS plugs or Gelfilm overlay myringoplasty.

Setting

Interventions were performed in the animal care facility of a tertiary care academic institution.

Subjects and Methods

Sixteen adult female chinchillas. Perforations were established under microscopic visualization with thermal cautery. The animals were examined six weeks later, and those ears with stable perforations were randomly assigned to repair with PGS or Gelfilm. All ears were evaluated six weeks after repair, and resected membranes underwent histological evaluation.

Results

Chronic perforations were established in 22 of 32 (69%) chinchilla tympanic membranes. Nineteen tympanic membranes were included in the study group (3 ears were excluded secondary to death from anesthesia during the repair); 11 were implanted with PGS, and eight underwent Gelfilm myringoplasty. Of the 11 tympanic membranes implanted with PGS, 10 were healed at six weeks, while six of the eight tympanic membranes repaired with Gelfilm had healed at six weeks. Imaging of the medial mucosal and lateral epithelial surfaces of the tympanic membranes revealed PGS plug incorporation with neovascularization. Histology demonstrated a confluent cell layer on both sides of the graft.

Conclusions

PGS plugs are easily placed and allow for perforation closure and graft neovascularization in a chinchilla model.     

Replication and meta-analysis of 13,000 cases defines the risk for interleukin-23 receptor and autophagy-related 16-like 1 variants in Crohn��s disease

BACKGROUND/OBJECTIVE:

Variants in the interleukin-23 receptor (IL23R) and the autophagy-related 16-like 1 (ATG16L1) genes have been associated with an increased risk of Crohn’s disease (CD). Both genes were identified through genome-wide association scans and subsequent studies have validated these associations. To assess the effect size of these variants, an independent case-control association study and meta-analysis were performed.

METHODS:

British Caucasian subjects with inflammatory bowel disease (n=500) and 877 ethnically matched controls were genotyped for the disease-associated variants in IL23R and ATG16L1. In addition, meta-analyses of 12,991 patients and 14,598 controls, and 11,909 patients and 15,798 controls, were conducted on independently published data for the associations between IL23R and ATG16L1 variants and CD, respectively.

RESULTS:

In the present cohort, both susceptibility variants showed highly significant associations, including IL23R (rs11209026, P=0.0006; OR 0.37; 95% CI 0.21 to 0.67) and ATG16L1 (rs2241880, P=0.0017; OR 1.36; 95% CI 1.12 to 1.66). The meta-analysis based on the random effects model showed similar combined effects for rs11209026 (n=26, OR 0.41; 95% CI 0.37 to 0.46) and rs2241880 (n=25, OR 1.33; 95% CI 1.28 to 1.39). There was no statistically significant gene-gene interaction between caspase recruitment domain (CARD15) variants and the IL23R or ATG16L1 polymorphisms (P=0.44 and P=0.24, respectively).

CONCLUSION:

The present cohort and meta-analysis provides strong evidence that, in addition to CARD15, polymorphisms in both IL23R and ATG16L1 alter susceptibility to CD and that these effects are consistent across all populations of European ancestry; however, only ATG16L1 is relevant to inflammatory bowel disease in the Asian population.