Elevated Wall Shear Stress in Aortic Type B Dissection May Relate to Retrograde Aortic Type A Dissection: A Computational Fluid Dynamics Pilot Study.

OBJECTIVE: Retrograde aortic type A dissection (RTAD) is a known complication in patients with aortic type B dissection. The purpose of this computational fluid dynamics (CFD) study was to identify haemodynamic risk factors for the occurrence of RTAD. METHODS: Computed tomographic angiography (CTA) images of 10 patients with type B dissections, who subsequently developed a RTAD, were retrospectively analysed together with patients constituting a control group (n = 10) where no further vascular events after the initial type B dissection occurred. CFD simulations were conducted based on 3D surface models of the aortic lumen derived from CTA datasets. For both groups, pressures, velocity magnitudes and wall shear stress (WSS) were compared at the site of the future RTAD entry tear and the surrounding aortic wall. RESULTS: WSS at the site of the future entry tear was significantly elevated compared with the surrounding wall (15.10 Pa vs. 5.15 Pa, p < .001) and was significantly higher in the RTAD group than in the control group (6.05 Pa, p < .002). Pressures and velocity magnitudes were not significantly elevated at the entry tear (3825.8 Pa, 0.63 m/s) compared with the aortic arch (3549.8 Pa, 0.50 m/s) or control group (3501.7 Pa, 0.62 m/s). CONCLUSIONS: Increased WSS accompanies the occurrence of RTAD. The results merit the design for a prospective study to confirm whether WSS is a risk factor for the occurrence of RTAD.

Investigating the heterogeneity of alkylating agents' efficacy and toxicity between sexes: A systematic review and meta-analysis of randomized trials comparing cyclophosphamide and ifosfamide (MAIAGE study).

BACKGROUND: A marginal interaction between sex and the type of alkylating agent was observed for event-free survival in the Euro-EWING99-R1 randomized controlled trial (RCT) comparing cyclophosphamide and ifosfamide in Ewing sarcoma. To further evaluate this interaction, we performed an individual patient data meta-analysis of RCTs assessing cyclophosphamide versus ifosfamide in any type of cancer. METHODS: A literature search produced two more eligible RCTs (EICESS92 and IRS-IV). The endpoints were progression-free survival (PFS, main endpoint) and overall survival (OS). The hazard ratios (HRs) of the treatment-by-sex interaction and their 95% confidence interval (95% CI) were assessed using stratified multivariable Cox models. Heterogeneity of the interaction across age categories and trials was explored. We also assessed this interaction for severe acute toxicity using logistic models. RESULTS: The meta-analysis comprised 1,528 pediatric and young adult sarcoma patients from three RCTs: Euro-EWING99-R1 (n = 856), EICESS92 (n = 155), and IRS-IV (n = 517). There were 224 PFS events in Euro-EWING99-R1 and 200 in the validation set (EICESS92 + IRS-IV), and 171 and 154 deaths in each dataset, respectively. The estimated treatment-by-sex interaction for PFS in Euro-EWING99-R1 (HR = 1.73, 95% CI = 1.00-3.00) was not replicated in the validation set (HR = 0.97, 95% CI = 0.55-1.72), without heterogeneity across trials (P = 0.62). In the pooled analysis, the treatment-by-sex interaction was not significant (HR = 1.31, 95% CI = 0.89-1.95, P = 0.17), without heterogeneity across age categories (P = 0.88) and trials (P = 0.36). Similar results were observed for OS. No significant treatment-by-sex interaction was observed for leucopenia/neutropenia (P = 0.45), infection (P = 0.64), or renal toxicity (P = 0.20). CONCLUSION: Our meta-analysis did not confirm the hypothesis of a treatment-by-sex interaction on efficacy or toxicity outcomes.

Parameningeal rhabdomyosarcoma in pediatric age: results of a pooled analysis from North American and European cooperative groups.

BACKGROUND: Parameningeal (PM) site is a well-known adverse prognostic factor in children with localized rhabdomyosarcoma (RMS). To identify risk factors associated with outcome at this site, we pooled data from 1105 patients treated in 10 studies conducted by European and North American cooperative groups between 1984 and 2004. PATIENTS AND METHODS: Clinical factors including age, histology, size, invasiveness, nodal involvement, Intergroup Rhabdomyosarcoma Study (IRS) clinical group, site, risk factors for meningeal involvement (MI), study group, and application of radiotherapy (RT) were studied for their impact on event-free and overall survival (EFS and OS). RESULTS: Ten-year EFS and OS were 62.6 and 66.1% for the whole group. Patients without initial RT showed worse survival (10-year OS 40.8% versus 68.5% for RT treated patients). Multivariate analysis focusing on 862 patients who received RT as part of their initial treatment revealed four unfavorable prognostic factors: age <3 or >10 years, signs of MI, unfavorable site, and tumor size. Utilizing these prognostic factors, patients could be classified into different risk groups with 10-year OS ranging between 51.1 and 80.9%. CONCLUSIONS: While, in general, PM localization is regarded as an adverse prognostic factor, the current analysis differentiates those with good prognosis (36% patients with 0-1 risk factor: 10-year OS 80.9%) from high-risk PM patients (28% with 3-4 factors: 10-year OS 51.1%). Furthermore, this analysis reinforces the necessity for RT in PM RMS.

Determining predictive metabolomic biomarkers of meniscal injury in dogs with cranial cruciate ligament rupture.

OBJECTIVES: This study used hydrogen nuclear magnetic resonance spectroscopy for the first time to examine differences in the metabolomic profile of stifle joint synovial fluid from dogs with cranial cruciate ligament rupture with and without meniscal injuries, in order to identify biomarkers of meniscal injury. Identifying a biomarker of meniscal injury could then ultimately be used to design a minimally invasive diagnostic test for meniscal injuries in dogs. MATERIALS AND METHODS: Stifle joint synovial fluid was collected from dogs undergoing stifle joint surgery or arthrocentesis for lameness investigations. We used multi-variate statistical analysis using principal component analysis and univariate statistical analysis using one-way analysis of variance and analysis of co-variance to identify differences in the metabolomic profile between dogs with cranial cruciate ligament rupture and meniscal injury, cranial cruciate ligament rupture without meniscal injury, and neither cranial cruciate ligament rupture nor meniscal injury, taking into consideration clinical variables. RESULTS: A total of 154 samples of canine synovial fluid were included in the study. Sixty-four metabolites were annotated to the hydrogen nuclear magnetic resonance spectroscopy spectra. Six spectral regions were found to be significantly altered (false discovery rate adjusted P-value <0.05) between groups with cranial cruciate ligament rupture with and without meniscal injury, including three attributed to nuclear magnetic resonance mobile lipids [mobile lipid -CH3 (P=0.016), mobile lipid -n(CH3 )3 (P=0.017), mobile unsaturated lipid (P=0.031)]. CLINICAL SIGNIFICANCE: We identified an increase in nuclear magnetic resonance mobile lipids in the synovial fluid of dogs with meniscal injury which are of interest as potential biomarkers of meniscal injury.

Risk-spreading larviposition behaviour of female nose bot flies (Cephenemyia) attacking black-tailed deer.

While baited deer models were under observation nine Cephenemyia jellisoni Townsend (Diptera: Oestridae) females and seven C. apicata Bennett & Sabrosky engaged in a risk-spreading larviposition behaviour by larvipositing on models only once and then flying away. Additionally, analysis of 225 unobserved larvipostions in which larvae were trapped in adhesive on the muzzles of deer models showed that 94% of C. apicata and 95% of C. jellisoni larviposited on a model only once. The number of single larvipositions was highly significant for both species. The principal adaptive significance of such risk-spreading larviposition behaviour is that it spreads the reproductive output of a female among many hosts, and in years when adult eclosion and survival rates are low, it ensures that the larvae of the few surviving females will be distributed among a maximum number of hosts. Several other benefits of such behaviour also are discussed.

Anatomical modifications, viviparous reproduction and hydraulic expulsion of larvae by Cephenemyia nasopharyngeal bot flies of deer.

Several specialized adaptations of the reproductive and respiratory systems associated with the retention and expulsion of larvae in ovoviviparous Cephenemyia species (Diptera: Oestridae) are described and illustrated. In these flies the anterior section of the common oviduct is modified into a large sac-like uterus that contains larvae, and the posterior section is modified into a larvipositor with a central tubular vagina. During larviposition, contraction of abdominal muscles forces haemolymph into a perivaginal sinus, causing a hydraulically driven exsertion of the larvipositor. A group of larvae and uterine fluid sealed off within the lumen of the vagina are then expelled from the vulva via hydraulic pressure as the stretched vagina is compressed. A one-way, non-return valve between the uterus and vagina prevents a reflux of larvae upward into the uterus during larviposition. All mutually dependent actions associated with larviposition occur almost simultaneously. All species have evolved a similar mechanism of expelling their larvae, but the shape of the non-return valve is different in each species studied.

Production of a severe cystic fibrosis mutation in mice by gene targeting.

We have used gene targeting in embryonic stem cells to introduce an HPRT mini-gene into the coding sequence of the murine cystic fibrosis gene (cftr). This insertion introduces a termination codon in frame with the cftr coding sequence to terminate prematurely the CFTR protein within the first nucleotide binding domain. Animals homozygous for the cftr disruption fail to thrive and display a range of symptoms including meconium ileus, distal intestinal obstructions, gastrointestinal mucus accumulation and blockage of pancreatic ducts. The animals also show lacrimal gland pathology. Tracheal and caecal transepithelial current measurements demonstrate the lack of a cAMP activatable Cl- channel. These animals will prove useful for the evaluation of new therapeutic drugs and gene therapy strategies.

Generation and characterization of a delta F508 cystic fibrosis mouse model.

We have generated mice carrying the most common mutation in cystic fibrosis (CF), delta F508, within the cystic fibrosis (Cftr) gene. Mutant animals show pathological and electrophysiological changes consistent with a CF phenotype. delta F508-/- mice die from peritonitis and show deficiencies in cAMP-activated electrogenic Cl- transport. These mice produce delta F508 transcripts and show the temperature-dependent trafficking defect first described for the human delta F508 CFTR protein. A functional CFTR Cl- channel not demonstrated by null CF mice or present at 37 degrees C was detected following incubation of epithelial cells at 27 degrees C. Thus, these mice are an accurate delta F508 model and will be valuable for testing drugs aimed at overcoming the delta F508 trafficking defect.

Mutations in the skeletal muscle alpha-actin gene in patients with actin myopathy and nemaline myopathy.

Muscle contraction results from the force generated between the thin filament protein actin and the thick filament protein myosin, which causes the thick and thin muscle filaments to slide past each other. There are skeletal muscle, cardiac muscle, smooth muscle and non-muscle isoforms of both actin and myosin. Inherited diseases in humans have been associated with defects in cardiac actin (dilated cardiomyopathy and hypertrophic cardiomyopathy), cardiac myosin (hypertrophic cardiomyopathy) and non-muscle myosin (deafness). Here we report that mutations in the human skeletal muscle alpha-actin gene (ACTA1) are associated with two different muscle diseases, 'congenital myopathy with excess of thin myofilaments' (actin myopathy) and nemaline myopathy. Both diseases are characterized by structural abnormalities of the muscle fibres and variable degrees of muscle weakness. We have identified 15 different missense mutations resulting in 14 different amino acid changes. The missense mutations in ACTA1 are distributed throughout all six coding exons, and some involve known functional domains of actin. Approximately half of the patients died within their first year, but two female patients have survived into their thirties and have children. We identified dominant mutations in all but 1 of 14 families, with the missense mutations being single and heterozygous. The only family showing dominant inheritance comprised a 33-year-old affected mother and her two affected and two unaffected children. In another family, the clinically unaffected father is a somatic mosaic for the mutation seen in both of his affected children. We identified recessive mutations in one family in which the two affected siblings had heterozygous mutations in two different exons, one paternally and the other maternally inherited. We also identified de novo mutations in seven sporadic probands for which it was possible to analyse parental DNA.

Corrected misidentification of first instars of the bot flies Cephenemyia apicata and C. jellisoni, with a review of the biology and life history of both species.

First instars obtained from the uteri of host-seeking females, and compared with previously published descriptions of larvae collected from Columbian black-tailed deer (Odocoileus hemionus columbianus), revealed that larvae described as Cephenemyia apicata Bennett & Sabrosky (Diptera: Oestridae) actually are C. jellisoni Townsend. Several new characters are added to supplement the original descriptions of the first instars of these species. Collections of all larvae from deer autopsied during different months established that the first instars of C. apicata undergo a long obligate period of development and growth in the bronchi before molting and migrating to the retropharyngeal pouches of deer. This is the first study to document an obligatory lung phase in the life history of a species of Cephenemyia. The lung phase of C. apicata is compared with that described for Pharyngomyia picta (Meigen) (Diptera: Oestridae) in European red deer. A literature review found that for all Cephenemyia species studied, as well as for P. picta, a 6-8 month period of development as first instars during the fall/winter months ensures that pupal development and eclosion of adults will occur during periods of favourable external environmental conditions.

Amphetamine and methamphetamine have a direct and differential effect on BV2 microglia cells.

A comparative analysis of the direct effects of amphetamine and methamphetamine exposure on BV2 microglia cells in the presence and absence of cellular debris was performed. A significant dose-dependent and treatment-dependent effect of amphetamine and methamphetamine on BV2 cells was demonstrated: methamphetamine, but not amphetamine, inhibited phagocytosis, and a differential regulation of cytokines was observed in response to amphetamine and methamphetamine.

The Viking viewer for connectomics: scalable multi-user annotation and summarization of large volume data sets.

Modern microscope automation permits the collection of vast amounts of continuous anatomical imagery in both two and three dimensions. These large data sets present significant challenges for data storage, access, viewing, annotation and analysis. The cost and overhead of collecting and storing the data can be extremely high. Large data sets quickly exceed an individual's capability for timely analysis and present challenges in efficiently applying transforms, if needed. Finally annotated anatomical data sets can represent a significant investment of resources and should be easily accessible to the scientific community. The Viking application was our solution created to view and annotate a 16.5 TB ultrastructural retinal connectome volume and we demonstrate its utility in reconstructing neural networks for a distinctive retinal amacrine cell class. Viking has several key features. (1) It works over the internet using HTTP and supports many concurrent users limited only by hardware. (2) It supports a multi-user, collaborative annotation strategy. (3) It cleanly demarcates viewing and analysis from data collection and hosting. (4) It is capable of applying transformations in real-time. (5) It has an easily extensible user interface, allowing addition of specialized modules without rewriting the viewer.

Situational changes in self-awareness influence 3- and 4-year-olds' self-regulation.

In adults, heightened self-awareness leads to adherence to socially valued norms, whereas lowered self-awareness is associated with antinormative behavior. Levels of self-awareness are influenced by environmental cues such as mirrors. Do situational changes in self-awareness also have an impact on preschoolers' self-regulation? Adherence to a socially valued standard was observed under different conditions of self-focus. In Experiment 1 the standard was prescribed ("don't look in the box"), and in Experiment 2 children had the opportunity to be altruistic. Heightened self-focus was induced using a large mirror. In a neutral condition, the nonreflective side of the mirror was shown. To lower self-focus, children wore a disguise. Preschoolers peeked less and showed more altruism when the mirror image was present. As found for adults, it appears that self-awareness leads 3- and 4-year-olds to adhere to salient social standards. These results suggest that self-focus has a socially adaptive regulatory function from an early age.

Semipermeable Hollow Fiber Phantoms for Development and Validation of Perfusion-Sensitive MR Methods and Signal Models.

Two semipermeable, hollow fiber phantoms for the validation of perfusion-sensitive magnetic resonance methods and signal models are described. Semipermeable hollow fibers harvested from a standard commercial hemodialysis cartridge serve to mimic tissue capillary function. Flow of aqueous media through the fiber lumen is achieved with a laboratory-grade peristaltic pump. Diffusion of water and solute species (e.g., Gd-based contrast agent) occurs across the fiber wall, allowing exchange between the lumen and the extralumenal space. Phantom design attributes include: i) small physical size, ii) easy and low-cost construction, iii) definable compartment volumes, and iv) experimental control over media content and flow rate.

RGS4 controls renal blood flow and inhibits cyclosporine-mediated nephrotoxicity.

Calcineurin inhibitors (CNI) are powerful immunomodulatory agents that produce marked renal dysfunction due in part to endothelin-1-mediated reductions in renal blood flow. Ligand-stimulated Gq protein signaling promotes the contraction of smooth muscle cells via phospholipase Cbeta-mediated stimulation of cytosolic calcium release. RGS4 is a GTPase activating protein that promotes the deactivation of Gq and Gi family members. To investigate the role of G protein-mediated signaling in the pathogenesis of CNI-mediated renal injury, we used mice deficient for RGS4 (rgs4(-/-)). Compared to congenic wild type control animals, rgs4(-/-) mice were intolerant of the CNI, cyclosporine (CyA), rapidly developing fatal renal failure. Rgs4(-/-) mice exhibited markedly reduced renal blood flow after CyA treatment when compared to congenic wild type control mice as measured by magnetic resonance imaging (MRI). Hypoperfusion was reversed by coadministration of CyA with the endothelin antagonist, bosentan. The MAPK/ERK pathway was activated by cyclosporine administration and was inhibited by cotreatment with bosentan. These results show that endothelin-1-mediated Gq protein signaling plays a key role in the pathogenesis of vasoconstrictive renal injury and that RGS4 antagonizes the deleterious effects of excess endothelin receptor activation in the kidney.

Metabolomic analysis of synovial fluid from Thoroughbred racehorses diagnosed with palmar osteochondral disease using magnetic resonance imaging.

BACKGROUND: Palmar osteochondral disease (POD) is a common cause of lameness in competition horses. Magnetic resonance imaging (MRI) is the most sensitive diagnostic modality currently available, however it may not be financially or logistically practical for routine screening of POD. There is increasing interest in the use of metabolomics for diagnosis prior to progression to irreversible damage. OBJECTIVES: To determine metabolite levels in synovial fluid (SF) of horses with a clinical diagnosis of POD based on diagnostic analgesia and MRI, with the hypothesis that metabolomic profiles differ between diseased and healthy joints. STUDY DESIGN: Prospective clinical study. METHODS: Synovial fluid was collected from metacarpo/tarsophalangeal joints (MC/TPJ) of 29 horses (n = 51 joints), including 14 controls (n = 26) and 15 cases (n = 25), the latter with lameness localised to the MC/TPJ and MR changes consistent with POD (n = 23). Spectra were produced using 1 H-nuclear magnetic resonance (NMR) spectroscopy and analysed. RESULTS: Twenty-five metabolites were recognised associated with various biosynthetic and degradation pathways. The metabolite abundances within the controls demonstrated increased variability compared with the clinical group. The low level of variance between the spectra of the two groups was explained by five principal components. Cross-validation of the cohort demonstrated modest separation of predictive power (R2  = 0.67; Q2  = 0.34). Although statistical significance was not achieved, the most influential metabolites were glucose and lactate. MAIN LIMITATIONS: The modest sample size and variation in signalment, background and presenting condition of the controls may have impacted the discriminative power of the constructed models. The lack of matched controls, differences in time of fluid collection and freezing times may have also reduced accuracy when representing metabolite profiles. CONCLUSIONS: This study identified and quantified metabolites present in MC/TPJ SF of clinical cases with POD.

Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to diagnose osteoarthritis in equine serum.

BACKGROUND: Reliable and validated biomarkers for osteoarthritis (OA) are currently lacking. OBJECTIVES: To develop an accurate and minimally invasive method to assess OA-affected horses and provide potential spectral markers indicative of disease. STUDY DESIGN: Observational, cross-sectional study. METHODS: Our cohort consisted of 15 horses with OA and 48 without clinical signs of the disease, which were used as controls. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was used to investigate serum samples (50 µL) collected from these horses. Spectral processing and multivariate analysis revealed differences and similarities, allowing for detection of spectral biomarkers that discriminated between the two cohorts. A supervised classification algorithm, namely principal component analysis coupled with quadratic discriminant analysis (PCA-QDA), was applied to evaluate the diagnostic accuracy. RESULTS: Segregation between the two different cohorts, OA-affected and controls, was achieved with 100% sensitivity and specificity. The six most discriminatory peaks were attributed to proteins and lipids. Four of the spectral peaks were elevated in OA horses, which could be potentially due to an increase in lipids, protein expression levels and collagen, all of which have been previously reported in OA. Two peaks were found decreased and were tentatively assigned to the reduction of proteoglycan content that is observed during OA. MAIN LIMITATIONS: The control group had a wide range of ages and breeds. Presymptomatic OA cases were not included. Therefore, it remains unknown whether this test could also be used as an early diagnostic tool. CONCLUSIONS: This spectrochemical approach could provide an accurate and cost-effective blood test, facilitating point-of-care diagnosis of equine OA.

Retrieval of information from long-term memory.

Information is represented in long-term memory as a network of associations among concepts. Information is retrieved by spreading activation from concepts in working memory through the network structure. The time required to retrieve information is a function of the level of activation that it achieves. Fanning of multiple paths from a node dissipates the activation the node sends down any path and increases retrieval time. Fan effects are reduced as subjects overlearn the material or when they can change their task from a recognition judgment to a consistency judgment.

Trypanosome transmitted by Phlebotomus: first report from the Americas.

Transmission studies carried out in the laboratory incriminated Phlebotomus vexator occidentis as a vector of a species of trypanosome that infects Bufo boreas halophilus. Toads free of parasites contracted the trypanosome after eating infected flies and after intraperitoneal inoculation of flagellates cultured from the hindgut of flies that had fed on infected toads. Discovery of this vectorhost-parasite system in the Americas, and the localization of promastigote flagellates (leptomonads) in the hindgut of the vector, should assist in clarifying interpretative problems associated with infection of wild-caught flies in studies on leishmaniasis in the Americas and elsewhere.

Regulatory role of parasites: impact on host population shifts with resource availability.

Effects of infections by the ciliate Lambornella clarki on larval populations of its mosquito host Aedes sierrensis were examined in laboratory and field studies. When host populations developed with sufficient food, mortality from parasites was additive and reduced the number of emerging mosquitoes. For food-limited populations, mortality was compensatory or depensatory; emerging adults were as or more abundant with higher average fitness than those from uninfected control populations. When nutrients were scarce, parasitic infections relaxed larval competition and increased per capita food by reducing host abundance. Food limitation altered larval feeding behavior, reducing horizontal transmission and subsequent mortality from parasitism.