240 research outputs found
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Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows
The flow inside a purpose built enlarged single-orifice nozzle replica is quantified using time-averaged X-ray micro-computed tomography (micro-CT) and high-speed shadowgraphy. Results have been obtained at Reynolds and cavitation numbers similar to those of real-size injectors. Good agreement for the cavitation extent inside the orifice is found between the micro-CT and the corresponding temporal mean 2D cavitation image, as captured by the high-speed camera. However, the internal 3D structure of the developing cavitation cloud reveals a hollow vapour cloud ring formed at the hole entrance and extending only at the lower part of the hole due to the asymmetric flow entry. Moreover, the cavitation volume fraction exhibits a significant gradient along the orifice volume. The cavitation number and the needle valve lift seem to be the most influential operating parameters, while the Reynolds number seems to have only small effect for the range of values tested. Overall, the study demonstrates that use of micro-CT can be a reliable tool for cavitation in nozzle orifices operating under nominal steady-state conditions
Crystal Structure of an Integron Gene Cassette-Associated Protein from Vibrio cholerae Identifies a Cationic Drug-Binding Module
Background
The direct isolation of integron gene cassettes from cultivated and environmental microbial sources allows an assessment of the impact of the integron/gene cassette system on the emergence of new phenotypes, such as drug resistance or virulence. A structural approach is being exploited to investigate the modularity and function of novel integron gene cassettes.
Methodology/Principal Findings
We report the 1.8 A crystal structure of Cass2, an integron-associated protein derived from an environmental V. cholerae. The structure defines a monomeric beta-barrel protein with a fold related to the effector-binding portion of AraC/XylS transcription activators. The closest homologs of Cass2 are multi-drug binding proteins, such as BmrR. Consistent with this, a binding pocket made up of hydrophobic residues and a single glutamate side chain is evident in Cass2, occupied in the crystal form by polyethylene glycol. Fluorescence assays demonstrate that Cass2 is capable of binding cationic drug compounds with submicromolar affinity. The Cass2 module possesses a protein interaction surface proximal to its drug-binding cavity with features homologous to those seen in multi-domain transcriptional regulators.
Conclusions/Significance
Genetic analysis identifies Cass2 to be representative of a larger family of independent effector-binding proteins associated with lateral gene transfer within Vibrio and closely-related species. We propose that the Cass2 family not only has capacity to form functional transcription regulator complexes, but represents possible evolutionary precursors to multi-domain regulators associated with cationic drug compounds.National Health and Medical Research Council (Australia) (NHMRC grant 488502)National Institutes of Health (U.S.) (Grant GM62414-0 )Ontario. Ministry of Revenue (Challenge Fund
Lung epithelial stem cells and their niches : Fgf10 takes center stage
Throughout life adult animals crucially depend on stem cell populations to maintain and repair their tissues to ensure life-long organ function. Stem cells are characterized by their capacity to extensively self-renew and give rise to one or more differentiated cell types. These powerful stem cell properties are key to meet the changing demand for tissue replacement during normal lung homeostasis and regeneration after lung injury. Great strides have been made over the last few years to identify and characterize lung epithelial stem cells as well as their lineage relationships. Unfortunately, knowledge on what regulates the behavior and fate specification of lung epithelial stem cells is still limited, but involves communication with their microenvironment or niche, a local tissue environment that hosts and influences the behaviors or characteristics of stem cells and that comprises other cell types and extracellular matrix. As such, an intimate and dynamic epithelial-mesenchymal cross-talk, which is also essential during lung development, is required for normal homeostasis and to mount an appropriate regenerative response after lung injury. Fibroblast growth factor 10 (Fgf10) signaling in particular seems to be a well-conserved signaling pathway governing epithelial-mesenchymal interactions during lung development as well as between different adult lung epithelial stem cells and their niches. On the other hand, disruption of these reciprocal interactions leads to a dysfunctional epithelial stem cell-niche unit, which may culminate in chronic lung diseases such as chronic obstructive pulmonary disease (COPD), chronic asthma and idiopathic pulmonary fibrosis (IPF)
Frequency and outcomes of gastrostomy insertion in a longitudinal cohort study of atypical parkinsonism
\ua9 2024 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.Background: Multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) show a high prevalence and rapid progression of dysphagia, which is associated with reduced survival. Despite this, the evidence base for gastrostomy is poor, and the optimal frequency and outcomes of this intervention are not known. We aimed to characterise the prevalence and outcomes of gastrostomy in patients with these three atypical parkinsonian disorders. Method: We analysed data from the natural history and longitudinal cohorts of the PROSPECT-M-UK study with up to 60 months of follow-up from baseline. Survival post-gastrostomy was analysed using Kaplan–Meier survival curves. Results: In a total of 339 patients (mean age at symptom onset 63.3 years, mean symptom duration at baseline 4.6 years), dysphagia was present in >50% across all disease groups at baseline and showed rapid progression during follow-up. Gastrostomy was recorded as recommended in 44 (13%) and performed in 21 (6.2%; MSA 7, PSP 11, CBS 3) of the total study population. Median survival post-gastrostomy was 24 months compared with 12 months where gastrostomy was recommended but not done (p = 0.008). However, this was not significant when correcting for age and duration of symptoms at the time of procedure or recommendation. Conclusions: Gastrostomy was performed relatively infrequently in this cohort despite the high prevalence of dysphagia. Survival post-gastrostomy was longer than previously reported, but further data on other outcomes and clinician and patient perspectives would help to guide use of this intervention in MSA, PSP and CBS
The direct cost of "Thriasio" school screening program
<p>Abstract</p> <p>Background</p> <p>There is great diversity in the policies for scoliosis screening worldwide. The initial enthusiasm was succeeded by skepticism and the worth of screening programs has been challenged. The criticisms of school screening programs cite mainly the negative psychological impact on children and their families and the increased financial cost of visits and follow-up radiographs. The purpose of this report is to evaluate the direct cost of performing the school screening in a district hospital.</p> <p>Methods</p> <p>A cost analysis was performed for the estimation of the direct cost of the "Thriasio" school-screening program between January 2000 and May 2006. The analysis involved all the 6470 pupils aged 6–18 years old who were screened at schools for spinal deformities during this period. The factors which were taken into consideration in order to calculate the direct cost of the screening program were a) the number of the examiners b) the working hours, c) the examiners' salary, d) the cost of transportation and finally e) the cost of examination per child.</p> <p>Results</p> <p>During the examined period 20 examiners were involved in the program and worked for 1949 working hours. The hourly salary for the trainee doctors was 6.80 euro, for the Health Visitors 6.70 euro and for the Physiotherapists 5.50 euro in current prices. The cost of transportation was 32 euro per year. The direct cost for the examination of each child for the above studied period was calculated to be 2.04 euro.</p> <p>Conclusion</p> <p>The cost of our school-screening program is low. The present study provides a strong evidence for the continuation of the program when looking from a financial point of view.</p
Myoferlin Depletion in Breast Cancer Cells Promotes Mesenchymal to Epithelial Shape Change and Stalls Invasion
Myoferlin (MYOF) is a mammalian ferlin protein with homology to ancestral Fer-1, a nematode protein that regulates spermatic membrane fusion, which underlies the amoeboid-like movements of its sperm. Studies in muscle and endothelial cells have reported on the role of myoferlin in membrane repair, endocytosis, myoblast fusion, and the proper expression of various plasma membrane receptors. In this study, using an in vitro human breast cancer cell model, we demonstrate that myoferlin is abundantly expressed in invasive breast tumor cells. Depletion of MYOF using lentiviral-driven shRNA expression revealed that MDA-MB-231 cells reverted to an epithelial morphology, suggesting at least some features of mesenchymal to epithelial transition (MET). These observations were confirmed by the down-regulation of some mesenchymal cell markers (e.g., fibronectin and vimentin) and coordinate up-regulation of the E-cadherin epithelial marker. Cell invasion assays using Boyden chambers showed that loss of MYOF led to a significant diminution in invasion through Matrigel or type I collagen, while cell migration was unaffected. PCR array and screening of serum-free culture supernatants from shRNAMYOF transduced MDA-MB-231 cells indicated a significant reduction in the steady-state levels of several matrix metalloproteinases. These data when considered in toto suggest a novel role of MYOF in breast tumor cell invasion and a potential reversion to an epithelial phenotype upon loss of MYOF
H5N1 Whole-Virus Vaccine Induces Neutralizing Antibodies in Humans Which Are Protective in a Mouse Passive Transfer Model
BACKGROUND: Vero cell culture-derived whole-virus H5N1 vaccines have been extensively tested in clinical trials and consistently demonstrated to be safe and immunogenic; however, clinical efficacy is difficult to evaluate in the absence of wide-spread human disease. A lethal mouse model has been utilized which allows investigation of the protective efficacy of active vaccination or passive transfer of vaccine induced sera following lethal H5N1 challenge. METHODS: We used passive transfer of immune sera to investigate antibody-mediated protection elicited by a Vero cell-derived, non-adjuvanted inactivated whole-virus H5N1 vaccine. Mice were injected intravenously with H5N1 vaccine-induced rodent or human immune sera and subsequently challenged with a lethal dose of wild-type H5N1 virus. RESULTS: Passive transfer of H5N1 vaccine-induced mouse, guinea pig and human immune sera provided dose-dependent protection of recipient mice against lethal challenge with wild-type H5N1 virus. Protective dose fifty values for serum H5N1 neutralizing antibody titers were calculated to be ≤1∶11 for all immune sera, independently of source species. CONCLUSIONS: These data underpin the confidence that the Vero cell culture-derived, whole-virus H5N1 vaccine will be effective in a pandemic situation and support the use of neutralizing serum antibody titers as a correlate of protection for H5N1 vaccines
Cognitive and neuropsychiatric profiles distinguish atypical parkinsonian syndromes
\ua9 2025 The Author(s).Atypical parkinsonian syndromes are distinguished from Parkinson\u27s disease (PD) by additional neurological signs and characteristic underlying neuropathology. However, they can be diagnostically challenging, rapidly progressive and are often diagnosed late in disease course. Their different demographic features and prognoses are well studied, but the accompanying cognitive and psychiatric features may also facilitate diagnosis. Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) may cause cognitive and behavioural manifestations that overlap with frontotemporal dementia, including non-fluent aphasia, apathy and impulsivity. Clinical diagnostic criteria have limited sensitivity, with pathologically confirmed PSP often having presented an initial clinical syndrome other than PSP-Richardson\u27s syndrome. Here, we integrate cross-sectional multicentre baseline data from the PROSPECT-M-UK and Oxford Discovery cohorts. This allowed us to compare cognitive and psychiatric features across a total of 1138 people with PSP, CBS, multiple-system atrophy (MSA) and idiopathic PD. Data from the different cohorts were harmonized and compared using multiple linear regression. There were five key results: (i) different syndromes showed distinctive cognitive profiles, using readily applicable \u27bedside\u27 screening tools. Frontal executive dysfunction was most evident in PSP, visuospatial deficits in CBS, with milder deficits in memory and executive function in MSA, as compared with PD; (ii) the most prevalent neuropsychiatric features were depression and anxiety in CBS, apathy in PSP, with sleep disturbances common in PD. As expected, apathy correlated positively with impulsivity across all disorders. Neuropsychiatric features were generally better at discriminating between atypical parkinsonian syndromes than were the cognitive domains; (iii) both cognitive function and motor severity declined with disease duration, and motor function predicted cognition in PSP, CBS and PD but not in MSA, suggesting that in MSA cognitive and motor dysfunction are decoupled; (iv) plasma neurofilament light chain (NFL) levels, measured in a subset of patients, correlated with cognitive deficits in PSP, but not motor deficits; (v) cognitive deficits contributed to the impairment in activities of daily living after controlling for motor severity, with every two points on the Montreal Cognitive Assessment worsening the Schwab and England score by one point. In anticipation of future neuroprotective therapies, we present a classifier to improve diagnostic accuracy for atypical parkinsonian syndromes in vivo. Longitudinal cohort studies with resources for neuropathological gold standard diagnosis remain important to validate better diagnostic tools for people with PSP, CBD, MSA and atypical parkinsonism
Long term effects of micro-surgical testicular sperm extraction on androgen status in patients with non obstructive azoospermia
BACKGROUND: The aim of our study was to review the results of microsurgically performed testicular sperm extraction (TESE) and to evaluate its possible long term effects on serum testosterone (T). METHODS: We operated on 48 men (35 +/- 8 years) with non-obstructive azoospermia (NOA). If no spermatozoa were found following a micro epididymal sperm extraction (Silber et al., 1994) and testicular biopsy, testicular microdissection was performed or multiple microsurgical testicular biopsies were taken. The mean follow-up of the serum T was 2.4 +/- 1.1 years. RESULTS: Sperm was retrieved in 17/48 (35%) of the men. The per couple take home baby rate if sperm was retrieved was 4/17 (24%). Serum T decreased significantly at follow-up (p < 0.05) and 5/31 (16%) de novo androgen deficiencies developed CONCLUSION: In patients with non-obstructive azoospermia in whom no spermatozoa were found following a micro epididymal sperm aspiration and a simple testicular biopsy, we were able to retrieve spermatozoa in 35% of the men. The take home baby rate was 24% among couples with spermatozoa present upon TESE. De novo androgen deficiency occurred in 16% of the male patients following TESE indicating that, in men with NOA, long term hormonal follow up is recommended after TESE
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