Observing a dynamical skeleton of turbulence in Taylor-Couette flow experiments.

Recent work shows that recurrent solutions of the equations governing fluid flow play an important role in structuring the dynamics of turbulence. Here, an improved version of an earlier method (Krygier et al. 2021 J. Fluid. Mech. 923, A7 and Crowley et al. 2022 Proc. Natl Acad. Sci. USA 119, e2120665119) is used for detecting and analyzing intervals of time when turbulence 'shadows' (spatially and temporally mimics) recurrent solutions in both numerical simulations and laboratory experiments. We find that all the recurrent solutions shadowed in numerics are also shadowed in experiment, and the corresponding statistics of shadowing agree. Our results set the stage for experimentally grounded dynamical descriptions of turbulence in a variety of wall-bounded shear flows, enabling applications to forecasting and control. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (part 1)'.

Trends in mortality from aortic dissection analyzed from the World Health Organization Mortality Database from 2000 to 2017.

BACKGROUND: We assessed trends in aortic dissection (AD) death rates in 23 countries from 2000 to 2017. METHODS: We extracted AD mortality data for countries with high usability data from the World Health Organization (WHO) Mortality Database and from the Center for Disease Control (CDC) WONDER Database for the United States of America (USA). Age Standardized Death Rates (ASDRs) per 100,000 population were computed. Trends were assessed by locally weighted scatter plot smoother (LOWESS) regression. RESULTS: Between 2000 and 2017, ASDRs from AD decreased in Australia, Belgium, Croatia, Denmark, France, Italy, New Zealand, Norway, Sweden, the United Kingdom, and the USA for both sexes. Increasing AD mortality was observed in Austria, Czech Republic, Germany, Hungary, Israel, and Japan for both sexes. The largest absolute increases in ASDR were in Japan for men (+1.59) and women (+1.11). The largest percentage decreases were in Norway for men (-0.91) and in New Zealand (-0.6) for women. In 2017, the highest mortality rates were in Japan for both sexes (3.22 and 2.09, respectively). The lowest ASDR was in Kyrgyzstan for both sexes (0.16 and 0.10, respectively). ASDRs for AD in 2017 were higher for men than women in all countries included. Spain had the greatest difference between the gender's mortality rates with a 2.71-fold higher mortality average rate in men. CONCLUSION: We identified an overall decrease in AD mortality in most included countries, while an increase was noted in other countries including Israel and Japan.

Radiation dose tracking in computed tomography: Red alerts and feedback. Implementing a radiation dose alert system in CT.

INTRODUCTION: This study investigates instances of elevated radiation dose on a radiation tracking system to determine their aetiologies. It aimed to investigate the impact of radiographer feedback on these alerts. METHODS: Over two six-month periods 11,298 CT examinations were assessed using DoseWatch. Red alerts (dose length products twice the median) were identified and two independent reviewers established whether alerts were true (unjustifiable) or false (justifiable). During the second time period radiographers used a feedback tool to state the cause of the alert. A Chi-Square test was used to assess whether red alert incidence decreased following the implementation of radiographer feedback. RESULTS: There were 206 and 357 alerts during the first and second time periods, respectively. These occurred commonly with CT pulmonary angiography, brain, and body examinations. Procedural documentation errors and patient size accounted for 57% and 43% of false alerts, respectively. Radiographer feedback was provided for 17% of studies; this was not associated with a significant change in the number of alerts, but the number of true alerts declined (from 7 to 3) (χ2 = 4.14; p = 0.04). CONCLUSION: Procedural documentation errors as well as patient-related factors are associated with false alerts in DoseWatch. Implementation of a radiographer feedback tool reduced true alerts. IMPLICATIONS FOR PRACTICE: The implementation of a radiographer feedback tool reduced the rate of true dose alerts. Low uptake with dose alert systems is an issue; the workflow needs to be considered to address this.

PTI-125 Reduces Biomarkers of Alzheimer's Disease in Patients.

BACKGROUND: The most common dementia worldwide, Alzheimer's disease is often diagnosed via biomarkers in cerebrospinal fluid, including reduced levels of Aß1-42, and increases in total tau and phosphorylated tau-181. Here we describe results of a Phase 2a study of a promising new drug candidate that significantly reversed all measured biomarkers of Alzheimer's disease, neurodegeneration and neuroinflammation. PTI-125 is an oral small molecule drug candidate that binds and reverses an altered conformation of the scaffolding protein filamin A found in Alzheimer's disease brain. Altered filamin A links to the α7-nicotinic acetylcholine receptor to allow Aß42's toxic signaling through this receptor to hyperphosphorylate tau. Altered filamin A also links to toll-like receptor 4 to enable Aß-induced persistent activation of this receptor and inflammatory cytokine release. Restoring the native shape of filamin A prevents or reverses filamin A's linkages to the α7-nicotinic acetylcholine receptor and toll-like receptor 4, thereby blocking Aß42's activation of these receptors. The result is reduced tau hyperphosphorylation and neuroinflammation, with multiple functional improvements demonstrated in transgenic mice and postmortem Alzheimer's disease brain. OBJECTIVES: Safety, pharmacokinetics, and cerebrospinal fluid and plasma biomarkers were assessed following treatment with PTI-125 for 28 days. Target engagement and mechanism of action were assessed in patient lymphocytes by measuring 1) the reversal of filamin A's altered conformation, 2) linkages of filamin A with α7-nicotinic acetylcholine receptor or toll-like receptor 4, and 3) levels of Aß42 bound to α7-nicotinic acetylcholine receptor or CD14, the co-receptor for toll-like receptor 4. DESIGN: This was a first-in-patient, open-label Phase 2a safety, pharmacokinetics and biomarker study. SETTING: Five clinical trial sites in the U.S. under an Investigational New Drug application. PARTICIPANTS: This study included 13 mild-to-moderate Alzheimer's disease patients, age 50-85, Mini Mental State Exam ≥16 and ≤24 with a cerebrospinal fluid total tau/Aß42 ratio ≥0.30. INTERVENTION: PTI-125 oral tablets (100 mg) were administered twice daily for 28 consecutive days. MEASUREMENTS: Safety was assessed by electrocardiograms, clinical laboratory analyses and adverse event monitoring. Plasma levels of PTI-125 were measured in blood samples taken over 12 h after the first and last doses; cerebrospinal fluid levels were measured after the last dose. Commercial enzyme linked immunosorbent assays assessed levels of biomarkers of Alzheimer's disease in cerebrospinal fluid and plasma before and after treatment with PTI-125. The study measured biomarkers of pathology (pT181 tau, total tau and Aß42), neurodegeneration (neurofilament light chain and neurogranin) and neuroinflammation (YKL-40, interleukin-6, interleukin-1ß and tumor necrosis factor α). Plasma levels of phosphorylated and nitrated tau were assessed by immunoprecipitation of tau followed by immunoblotting of three different phospho-epitopes elevated in AD (pT181-tau, pS202-tau and pT231-tau) and nY29-tau. Changes in conformation of filamin A in lymphocytes were measured by isoelectric focusing point. Filamin A linkages to α7-nicotinic acetylcholine receptor and toll-like receptor 4 were assessed by immunoblot detection of α7-nicotinic acetylcholine receptor and toll-like receptor 4 in anti-filamin A immunoprecipitates from lymphocytes. Aß42 complexed with α7-nicotinic acetylcholine receptor or CD14 in lymphocytes was also measured by co-immunoprecipitation. The trial did not measure cognition. RESULTS: Consistent with the drug's mechanism of action and preclinical data, PTI-125 reduced cerebrospinal fluid biomarkers of Alzheimer's disease pathology, neurodegeneration and neuroinflammation from baseline to Day 28. All patients showed a biomarker response to PTI-125. Total tau, neurogranin, and neurofilament light chain decreased by 20%, 32% and 22%, respectively. Phospho-tau (pT181) decreased 34%, evidence that PTI-125 suppresses tau hyperphosphorylation induced by Aß42's signaling through α7-nicotinic acetylcholine receptor. Cerebrospinal fluid biomarkers of neuroinflammation (YKL-40 and inflammatory cytokines) decreased by 5-14%. Biomarker effects were similar in plasma. Aß42 increased slightly - a desirable result because low Aß42 indicates Alzheimer's disease. This increase is consistent with PTI-125's 1,000-fold reduction of Aß42's femtomolar binding affinity to α7-nicotinic acetylcholine receptor. Biomarker reductions were at least p ≤ 0.001 by paired t test. Target engagement was shown in lymphocytes by a shift in filamin A's conformation from aberrant to native: 93% was aberrant on Day 1 vs. 40% on Day 28. As a result, filamin A linkages with α7-nicotinic acetylcholine receptor and toll-like receptor 4, and Aß42 complexes with α7-nicotinic acetylcholine receptor and CD14, were all significantly reduced by PTI-125. PTI-125 was safe and well-tolerated in all patients. Plasma half-life was 4.5 h and approximately 30% drug accumulation was observed on Day 28 vs. Day 1. CONCLUSIONS: PTI-125 significantly reduced biomarkers of Alzheimer's disease pathology, neurodegeneration, and neuroinflammation in both cerebrospinal fluid and plasma. All patients responded to treatment. The magnitude and consistency of reductions in established, objective biomarkers imply that PTI-125 treatment counteracted disease processes and reduced the rate of neurodegeneration. Based on encouraging biomarker data and safety profile, approximately 60 patients with mild-to-moderate AD are currently being enrolled in a Phase 2b randomized, placebo-controlled confirmatory study to assess the safety, tolerability and efficacy of PTI-125.

An optimized non-destructive protocol for testing mechanical properties in decellularized rabbit trachea.

Successful tissue-engineered tracheal transplantation relies on the use of non-immunogenic constructs, which can vascularize rapidly, support epithelial growth, and retain mechanical properties to that of native trachea. Current strategies to assess mechanical properties fail to evaluate the trachea to its physiological limits, and lead to irreversible destruction of the construct. Our aim was to develop and evaluate a novel non-destructive method for biomechanical testing of tracheae in a rabbit decellularization model. To validate the performance of this method, we simultaneously analyzed quantitative and qualitative graft changes in response to decellularization, as well as in vivo biocompatibility of implanted scaffolds. Rabbit tracheae underwent two, four and eight cycles of detergent-enzymatic decellularization. Biomechanical properties were analyzed by calculating luminal volume of progressively inflated and deflated tracheae with microCT. DNA, glycosaminoglycan and collagen contents were compared to native trachea. Scaffolds were prelaminated in vivo. Native, two- and four-cycle tracheae showed equal mechanical properties. Collapsibility of eight-cycle tracheae was significantly increased from -40cm H2O (-3.9kPa). Implantation of two- and four-cycle decellularized scaffolds resulted in favorable flap-ingrowth; eight-cycle tracheae showed inadequate integration. We showed a more limited detergent-enzymatic decellularization successfully removing non-cartilaginous immunogenic matter without compromising extracellular matrix content or mechanical stability. With progressive cycles of decellularization, important loss of functional integrity was detected upon mechanical testing and in vivo implantation. This instability was not revealed by conventional quantitative nor qualitative architectural analyses. These experiments suggest that non-destructive, functional evaluation, e.g. by microCT, may serve as an important tool for mechanical screening of scaffolds before clinical implementation. STATEMENT OF SIGNIFICANCE: Decellularization is a front-running strategy to generate scaffolds for tracheal tissue-engineering. Preservation of biomechanical properties of the trachea during this process is paramount to successful clinical transplantation. In this paper, we evaluated a novel method for biomechanical testing of decellularized trachea. We detected important loss of functional integrity with progressive cycles of decellularization. This instability was not revealed by our quantitative nor qualitative analyses. These experiments suggest that the technique might serve as a performant, non-destructive tool for mechanical screening of scaffolds before clinical implementation.

Effect of nasal continuous positive airway pressure on the pharyngeal swallow in neonates.

OBJECTIVE: Feeding neonates orally while on nasal continuous positive airway pressure (nCPAP) is a common practice. We hypothesize that pressurized airflow provided by nCPAP will alter the swallowing mechanism in neonates, increasing the risk of aspiration during oral feeding. STUDY DESIGN: Infants receiving nCPAP with a RAM cannula and tolerating at least 50% of their feeding orally were included in the study (one term; six preterm infants). Each participant underwent a videofluoroscopic swallow study while on nCPAP and off nCPAP. A non-parametric signed-rank test was used for paired data. RESULT: The incidence of deep penetration (P=0.03) and aspiration (P=0.01) decreased significantly off-nCPAP compared with on-nCPAP. However, the incidence of mild penetration (P=0.65) and nasopharyngeal reflux (P=0.87) remained the same under both conditions. CONCLUSION: Oral feeding while on-nCPAP significantly increases the risk of laryngeal penetration and tracheal aspiration events. We recommend caution when initiating oral feedings on nCPAP.

A Quality Improvement Approach to Reducing the Caesarean section Surgical Site Infection Rate in a Regional Hospital.

Surgical site infection (SSI) rates are used extensively by hospitals as a basis for quality improvement. A 30-day post-discharge SSI programme for Caesarean section operations has been implemented in Our Lady of Lourdes Hospital since 2011. It has been shown that skin antisepsis and antibiotic prophylaxis are key factors in the prevention of SSI. Using quality improvement methodology, an infection prevention bundle was introduced to address these two factors. Skin antisepsis was changed from povidone-iodine to chlorhexidine-alcohol. Compliance with choice of antibiotic prophylaxis increased from 89.6% in 2014 to 98.5% in 2015. Compliance with timing also improved. The SSI rate of 7.5% was the lowest recorded to date, with the majority of SSIs (64%) diagnosed after hospital discharge. The level of variation was also reduced. However, the continued presence of variation and possibility of lower infection rates from the literature imply that further improvements are required.

Tissue-Engineered Tracheal Replacement in a Child: A 4-Year Follow-Up Study.

In 2010, a tissue-engineered trachea was transplanted into a 10-year-old child using a decellularized deceased donor trachea repopulated with the recipient's respiratory epithelium and mesenchymal stromal cells. We report the child's clinical progress, tracheal epithelialization and costs over the 4 years. A chronology of events was derived from clinical notes and costs determined using reference costs per procedure. Serial tracheoscopy images, lung function tests and anti-HLA blood samples were compared. Epithelial morphology and T cell, Ki67 and cleaved caspase 3 activity were examined. Computational fluid dynamic simulations determined flow, velocity and airway pressure drops. After the first year following transplantation, the number of interventions fell and the child is currently clinically well and continues in education. Endoscopy demonstrated a complete mucosal lining at 15 months, despite retention of a stent. Histocytology indicates a differentiated respiratory layer and no abnormal immune activity. Computational fluid dynamic analysis demonstrated increased velocity and pressure drops around a distal tracheal narrowing. Cross-sectional area analysis showed restriction of growth within an area of in-stent stenosis. This report demonstrates the long-term viability of a decellularized tissue-engineered trachea within a child. Further research is needed to develop bioengineered pediatric tracheal replacements with lower morbidity, better biomechanics and lower costs.

Development of resorbable nanocomposite tracheal and bronchial scaffolds for paediatric applications.

BACKGROUND: Congenital tracheal defects and prolonged intubation following premature birth have resulted in an unmet clinical need for tracheal replacement. Advances in stem cell technology, tissue engineering and material sciences have inspired the development of a resorbable, nanocomposite tracheal and bronchial scaffold. METHODS: A bifurcated scaffold was designed and constructed using a novel, resorbable nanocomposite polymer, polyhedral oligomeric silsesquioxane poly(ϵ-caprolactone) urea urethane (POSS-PCL). Material characterization studies included tensile strength, suture retention and surface characteristics. Bone marrow-derived mesenchymal stem cells (bmMSCs) and human tracheobronchial epithelial cells (HBECs) were cultured on POSS-PCL for up to 14 days, and metabolic activity and cell morphology were assessed. Quantum dots conjugated to RGD (l-arginine, glycine and l-aspartic acid) tripeptides and anticollagen type I antibody were then employed to observe cell migration throughout the scaffold. RESULTS: POSS-PCL exhibited good mechanical properties, and the relationship between the solid elastomer and foam elastomer of POSS-PCL was comparable to that between the cartilaginous U-shaped rings and interconnective cartilage of the native human trachea. Good suture retention was also achieved. Cell attachment and a significant, steady increase in proliferation were observed for both cell types (bmMSCs, P = 0·001; HBECs, P = 0·003). Quantum dot imaging illustrated adequate cell penetration throughout the scaffold, which was confirmed by scanning electron microscopy. CONCLUSION: This mechanically viable scaffold successfully supports bmMSC and HBEC attachment and proliferation, demonstrating its potential as a tissue-engineered solution to tracheal replacement.

Autosomal recessive bestrophinopathy associated with angle-closure glaucoma.

PURPOSE: Abnormalities in the BEST1 gene have recently been recognised as causing autosomal recessive bestrophinopathy (ARB). ARB has been noted to have a variable phenotypic presentation, distinct from that of autosomal dominant Best vitelliform macular dystrophy (BVMD). Both conditions are associated with deposits in the retina, a reduced or absent electro-oculography (EOG) light rise, and the risk of developing angle-closure glaucoma. Herein, we describe the clinical and genetic characteristics of a young male diagnosed with ARB associated with angle-closure glaucoma resulting from a novel homozygous mutation in BEST1. METHODS: All research involved in this case adhered to the tenets of the Declaration of Helsinki. The proband underwent slitlamp examination, retinal autofluorescence imaging and optical coherence tomography after presenting with deteriorating vision. The findings prompted genetic testing with bi-directional DNA sequencing of coding and flanking intronic regions of BEST1. The proband's family members were subsequently screened. RESULTS: A provisional diagnosis of ARB was made based on the findings of subretinal and schitic lesions on fundoscopy and retinal imaging, together with abnormal EOG and electroretinography. Genetic testing identified a novel homozygous mutation in BEST1, c.636+1 G>A. Family members were found to carry one copy of the mutation and had no clinical or electrophysiological evidence of disease. The proband was additionally diagnosed with angle-closure glaucoma requiring topical therapy, peripheral iridotomies and phacoemulsification. CONCLUSIONS: Phenotypic overlap, reduced penetrance, variable expressivity and the ongoing discovery of new forms of bestrophinopathies add to the difficulty in distinguishing these retinal diseases. All patients diagnosed with ARB or BVMD should be examined for narrow angles and glaucoma, given their frequent association with these conditions.

Size does matter: can we reduce the radiotherapy field size for selected cases of anal canal cancer undergoing chemoradiation?

AIMS: Chemoradiation is the standard of care for the treatment of anal canal cancer, with surgery reserved for salvage. For tumours with uninvolved inguinal nodes, it is standard to irradiate the inguinal nodes prophylactically, resulting in large field sizes, which contribute to acute and late toxicity. The aim of this single-centre retrospective study was to determine if, in selected cases, prophylactic inguinal nodal irradiation could be avoided. MATERIALS AND METHODS: Between August 1998 and August 2004, 30 patients with biopsy-proven squamous cell anal canal cancer were treated with chemoradiation using one phase of treatment throughout. A three-field beam arrangement was used without attempting to treat the draining inguinal lymph nodes prophylactically. The radiotherapy dose prescribed was 50Gy in 25 daily fractions over 5 weeks. Concomitant chemotherapy was delivered with the radiation using mitomycin-C 7-12mg/m(2) on day 1 and protracted venous infusional 5-fluorouracil 200mg/m(2)/day throughout radiotherapy. RESULTS: All patients had clinically and radiologically uninvolved inguinal and pelvic nodes and all had primary lesions that were T3 or less. The median age at diagnosis was 65 years (range 41-84). The median follow-up was 41 months (range 24-113). The mean posterior field size was 14x15cm and the mean lateral field size was 12x15cm. All patients achieved a complete response. Ninety-four per cent of patients (28/30) were alive and disease free. The two patients who died did so of unrelated causes and were disease free at death. Four patients relapsed and all were salvaged with surgery; two for local disease requiring abdominoperineal resection, one with an inguinal nodal relapse requiring inguinofemoral block dissection and one for metastatic disease to the liver who underwent liver resection. CONCLUSIONS: This single-centre retrospective study supports the treatment for selected cases of anal canal cancer with smaller than standard radiation fields, avoiding prophylactic inguinal nodal irradiation. Hopefully this will translate into reduced acute and late toxicity. In future studies we would suggest that consideration is given as to whether omission of prophylactic inguinal nodal irradiation for early stage tumours should be explored.

Thermal stability of soy protein isolate and hydrolysate ingredients.

The objective of this study was to characterize the effects of pH, protein concentration and calcium supplementation on thermal stability, at 140°C, of soy protein isolate (SPI) and soy protein hydrolysate (SPH) ingredients. Increasing pH between 6.4 and 7.5 led to significantly (p<0.05) higher mean heat coagulation times (HCTs) at 140°C, for all soy protein ingredients at 1.8, and 3.6% (w/v) protein. Increasing protein concentration from 1.8 to 7.2% (w/v) led to shorter HCTs for protein dispersions. Calcium supplementation up to 850mg/L, except in the case of supplementation of SPI 1 with calcium citrate (CaCit), decreased HCT for soy protein ingredient dispersions, at pH 6.4 - 7.5. No significant differences (p<0.05) were found in mean HCT for dispersions supplemented with calcium chloride (CaCl2) and those supplemented with CaCit at 450, 650 and 850mg/L Ca(2+), in the pH range 6.4-7.5.

Influence of acid washing on the surface morphology of ionomer glasses and handling properties of glass ionomer cements.

Acid washing is known to influence the handling properties of ionomer glasses used in glass ionomer cements due to the production of an ion depleted-zone on the surface of the glass particles. The influence of acid washing on the particle size distribution and surface area of four glasses was examined by scanning electron microscopy (SEM), particle size analysis (PSA) and accelerated surface area porosimetry (ASAP) and the working and setting times of cements, produced from the glasses, correlated to changes in surface morphology. A linear relationship was found between the specific surface area of acid-washed SiO(2)-Al(2)O(3)-XF(2)-P(2)O(5) glasses (X being either calcium or strontium) and their cement working and setting times. These changes directly correlated with increases in the mesopore volume. However, the influence of acid washing on the surface morphology was also found to be glass composition-dependent with the addition of sodium into the glass network resulting in no significant change in the surface area or mesopore volume despite changes in the working and setting time. Through examination of the influence of acid washing and glass composition on the specific surface area improvements in the control of the working and setting times of glass ionomer cements may be achieved.

The influence of capsule geometry and cement formulation on the apparent viscosity of dental cements.

OBJECTIVES: This work examines the influence of specific aspects of capsule design and cement formulation on the handling properties of the extruded glass polyalkenoate cement (GPC) pastes. METHODS: A commercial metal reinforced GPC, HiDense, and experimental GPCs were extruded using a tensometer at loads and rates maintained within end-user limits and the apparent viscosity of the cement paste was determined by applying Poiseuille's law. The influence of the extrusion procedure (mixing time and ram speed), capillary geometry (length and diameter) and cement composition (powder: liquid (P:L) ratio, tartaric acid content and poly(acrylic acid) molar mass) on the apparent viscosity of the cement paste was evaluated. RESULTS: The examined GPCs behaved as non-Newtonian, pseudoplastic materials and exhibited a yield stress. Variation of the geometry of the capsule capillary resulted in the apparent viscosity of HiDense increasing by 7% as the length increased from 5 to 15mm whilst halving the capillary diameter from 2 to 1mm resulted in a 63% decrease in the apparent viscosity and a 600% increase in the extrusion load. The apparent viscosity of the experimental GPCs was increased by an increase in the P:L ratio and, in general, by the PAA molar mass, whilst the concentration-dependent effect of (+)-tartaric acid (TAA) indicates a working time dependence on TAA content. CONCLUSIONS: Using this approach optimisation of the rheological properties can be achieved by manipulation of the capsule design and cement formulation due to the dependency of the apparent viscosity on the capillary diameter, TAA content, P:L ratio and poly(acrylic acid) molar mass.

Mitochondrial perturbation attenuates bile acid-induced cytotoxicity.

Hydrophobic bile acids such as deoxycholate (DOC) are known to damage liver cells during cholestasis and promote colon cancer. Cellular stresses induced by bile acids, which include mitochondrial and endoplasmic reticulum (ER) stresses, can result in apoptosis. We found that inhibition of mitochondrial complexes I-V with rotenone, thenoyltrifluoroacetone (TTFA), antimycin A, myxothiazol or oligomycin strongly protected against DOC-induced apoptosis of HCT-116 cells. To understand the mechanism of this protection, we explored the ability of these specific inhibitors to reduce DOC-induced mitochondrial and ER stresses. Different inhibitors markedly reduced DOC-induction of mitochondrial condensation, the DOC-induced decrease in mitochondrial membrane potential and the DOC-induced dilatation of the ER (evidence of ER stress). A dramatic induction of nucleolar segregation by antimycin A and myxothiazol, two distinct complex III inhibitors, was also observed. These findings strongly implicate mitochondrial crosstalk with apoptotic signaling pathways and mitochondrial-nucleolar crosstalk in the development of apoptosis resistance in the colon.

Caspase-6 mediated cleavage of guanylate cyclase alpha 1 during deoxycholate-induced apoptosis: protective role of the nitric oxide signaling module.

Hydrophobic bile acids such as deoxycholate are known tumor promoters in the gastrointestinal tract. We have previously shown that deoxycholate induces apoptosis in colon epithelial cells and that these cells can be made resistant to deoxycholate-induced apoptosis. We now show that the nitric oxide synthase/nitric oxide/guanylate cyclase/cyclic guanosine monophosphate/cGMP-activated protein kinase (NOS/NO/GC/cGMP/PKG) signaling module contributes, in part, to the observed resistance of the cultured DOC-resistant colon epithelial cells (HCT-116R) using pharmacological inhibitors/antagonists (NS2028, Rp-8pCPT-cGMP, KT5823) of members of this signaling module. A novel finding from this study is the caspase-6 mediated cleavage of guanylate cyclase alpha 1 during deoxycholate-induced apoptosis of deoxycholate-sensitive HCT-116SA cells and the absence of guanylate cyclase alpha 1 cleavage in deoxycholate-treated HCT-116R resistant cells using Western blot analyses. This cleavage was specific to caspases as lysosomal, proteasomal, serine protease, cathepsin and calpain inhibitors failed to prevent the cleavage, whereas a general caspase inhibitor and a specific caspase-6 inhibitor did prevent guanylate cyclase alpha 1 cleavage.

Potential for the spread of Escherichia coli O157, Salmonella, and Campylobacter in the lairage environment at abattoirs.

Prevalences of Escherichia coli O157, Salmonella spp., and Campylobacter spp. were examined in 270 swabs taken from selected sites along the unloading-to-slaughter routes of animal movement in lairages of six commercial abattoirs, three for cattle and three for sheep. The overall prevalences of the pathogens in the respective lairage environments were compared with those for 270 swabs from the pelts of 90 lambs examined in the present study and 270 swabs from the hides of 90 cattle examined in a previous study that were slaughtered at the same abattoirs on the same days. Also, the results obtained were analyzed with the aim of identifying critical points at which animal-environment-animal transfer of the pathogens in lairages occurs. The results showed that (i) the overall prevalences of E. coli O157, Salmonella spp., and Campylobacter spp. were 27.2, 6.1, and 1.1%, respectively, in cattle lairages and 2.2, 1.1, and 5.6%, respectively, in sheep lairages; (ii) the overall prevalences of the three pathogens on cow hides (28.8, 17.7, and 0%, respectively) and sheep pelts (5.5, 7.8, and 0%, respectively) were higher than the overall prevalences in the respective lairage environments; (iii) the most frequently contaminated sites in cattle lairages were holding pen floors (50% of swabs positive for one or more pathogens), entrance gates of stun boxes (27.8% of swabs positive for one or more pathogens), and stun box floors (22.2% of swabs positive for one or more pathogens); (iv) the most frequently contaminated sites in sheep lairages were unloading ramp floors, holding pen floors, and water troughs (33.3, 22.2, and 22.2%, respectively); and (v) overall, cattle lairages and cow hides were more frequently contaminated with the pathogens than were lamb lairages and lamb pelts. Further research is needed to develop strategies for the incorporation of pathogen control in lairages into integrated microbial meat safety systems.

Use of molecular fingerprinting to assist the understanding of the epidemiology of Salmonella contamination within broiler production.

1. We analysed Salmonella isolates by conventional sero- and phage-typing, as well as by molecular techniques within the broiler production chain in two integrated companies. The most prevalent serovars were selected for genetic fingerprinting. 2. Isolates were first screened by plasmid profiling; subsequently, the most common plasmid types within the prevalent zoonotic serovars (enteritidis and typhimurium) and S. agama were further characterised by PstI-SphI ribotyping, and XbaI pulsed field gel electrophoresis (PFGE). 3. Salmonella binza, S. kedougou, and S. 4,12:d:- were endemic in the feed mills over long periods of time, and a variety of plasmid types for each of the serovars were found in the premises. 4. A similar situation was found with S. binza and S. senftenberg within the hatchery in company B. The Salmonella serovars which were resident in those locations were also the ones most widely distributed throughout the broiler flocks. 5. Plasmid profiling was useful to subdivide clusters of isolates within serovars, but for each serovar a high percentage (36 to 79%) of the isolates tested fall within a prevalent plasmid type. 6. A more detailed genetic analysis of the isolates by a multiple typing approach allowed for further strain differentiation, and allowed some epidemiological conclusions to be drawn.

Overexpression of the retinoic acid-responsive gene Stra6 in human cancers and its synergistic induction by Wnt-1 and retinoic acid.

Genetic defects in the Wnt-1 signaling pathway contribute to human tumor progression and are especially prevalent in colorectal cancer. We screened mouse C57MG cells to isolate mRNAs induced by Wnt-1 and identified Stra6, an mRNA known to be up-regulated by retinoic acid. Up-regulation of Stra6 mRNA was also observed in hyperplastic mammary tissue and mammary gland tumors from transgenic mice expressing Wnt-1 and in human tumors that frequently harbor defects in Wnt-1 signaling. Stimulation of C57MG cells with retinoic acid plus Wnt-1 resulted in expression of Stra6 transcript to levels greatly exceeding that observed with either stimulus alone. This synergy could be explained in part by the up-regulation of retinoic acid receptor-gamma that was observed in response to Wnt-1 signaling. Accordingly, treatment of human colorectal cancer cell lines with retinoic acid resulted in the up-regulation of Stra6 mRNA and accumulation of Stra6 protein at the cell membrane. The data support a model in which Wnt-1 signaling synergizes with retinoids to activate retinoic acid receptor-gamma-responsive genes in human cancers.