292 research outputs found
AN INNOVATIVE NUMERICAL APPROACH FOR TRAIN PASS-BY NOISE FORECASTING
This paper deals with an engineering method for the prediction of vehicle pass-by noise based on a FEM/ BEM exterior acoustic calculation in the frequency domain. The researchers simulate, in a virtual environment, the experimental outdoor pass-by noise measurement. The simulated pass-by noise campaign is synthesized from multiple acoustic transfer functions between a line of virtual microphones located 7.5m on the side of the vehicle and each noise source. A numerical FEM/BEM train bogie acoustic model has been created within the MSC ACTRAN commercial softwares. Wheel-rail rolling noise, engine and powertrain noise acoustic source have been implemented and posi-tioned inside the FEM and BEM model to demonstrate the validity of the proposed methods. The contribu-tion from noise sources, expressed both in terms of sound pressure level and overall value, to the pass-by noise were evaluated up to 5 kHz. The virtual pass-by-noise assessment has been then validated by experi-mental measurement of the complete four coach’s train with respect to different speed regimes
HPLC-UV and LC-MS/MS analysis to study formulation and long-term stability of some anticancer drugs in elastomeric pumps
Drug stability evaluations in elastomeric pump represent the first step to certify the safety of a therapeutic treatment in oncology. Since the stability of several anticancer molecules is due to their reactivity and stability in elastomeric pumps, made up of different materials, several experimental conditions, such as temperature, pH, concentration and possible chemical interactions among drugs in a single formulation, should be always investigated. Galenic preparation of anticancer drugs is an important prerogative of Anticancer Units within hospital pharmacies and, considering the burden of COVID-19 pandemic event, specific guidelines for therapeutic administration in elastomeric pumps reducing hospitalization both for post-surgical treatment and for therapeutic treatment have been worldwide elaborated. In the present study, the stability of Doxorubicin and Vincristine as a single formulation at different experimental conditions has been investigated. Moreover, we report a systematic study of 5-FU, which is known to be largely used in these medical devices, although its criticisms in terms of solubility, pH effect, storage time and conditions. Our results demonstrate that doxorubicin and vincristine can be mixed safely as a single formulation and 5-FU is stable for 32 days at different temperatures and concentrations in elastomeric pumps
Biotechnological Transformation of Hydrocortisone into 16α-Hydroxyprednisolone by Coupling Arthrobacter simplex and Streptomyces roseochromogenes
16α-Hydroxyprednisolone, an anti-inflammatory drug, could be potentially obtained from hydrocortisone bioconversion by combining a 1,2-dehydrogenation reaction performed by Arthrobacter simplexATCC31652 with a 16α-hydroxylation reaction by Streptomyces roseochromogenes ATCC13400. In this study we tested, for the first time, potential approaches to couple the two reactions using similar pH and temperature conditions for hydrocortisone bioconversion by the two strains. The A. simplex capability to 1,2-dehydrogenate the 16α-hydroxyhydrocortisone, the product of S. roseochromogenes transformation of hydrocortisone, and vice versa the capability of S. roseochromogenes to 16α-hydroxylate the prednisolone were assessed. Bioconversions were studied in shake flasks and strain morphology changes were observed by SEM. Whole cell experiments were set up to perform the two reactions in a sequential mode in alternate order or contemporarily at diverse temperature conditions. A. simplex catalyzed either the dehydrogenation of hydrocortisone into prednisolone efficiently or of 16α-hydroxyhydrocortisone into 16α-hydroxyprednisolone in 24 h (up to 93.9%). Surprisingly S. roseochromogenes partially converted prednisolone back to hydrocortisone. A 68.8% maximum of 16α-hydroxyprednisolone was obtained in 120-h bioconversion by coupling whole cells of the two strains at pH 6.0 and 26 °C. High bioconversion of hydrocortisone into 16α-hydroxyprednisolone was obtained for the first time by coupling A. simplex and S. roseochromogenes
Agave negatively regulates YAP and TAZ transcriptionally and post-translationally in osteosarcoma cell lines
Osteosarcoma (OS) is the most aggressive type of primary solid tumor that develops in bone. Whilst conventional chemotherapy can improve survival rates, the outcome for patients with metastatic or recurrent OS remains poor, so novel treatment agents and strategies are required. Research into new anticancer therapies has paved the way for the utilisation of natural compounds as they are typically less expensive and less toxic compared to conventional chemotherapeutics. Previously published works indicate that Agave exhibits anticancer properties, however potential molecular mechanisms remain poorly understood. In the present study, we investigate the anticancer effects of Agave leaf extract in OS cells suggesting that Agave inhibits cell viability, colony formation, and cell migration, and can induce apoptosis in OS cell lines. Moreover, Agave sensitizes OS cells to cisplatin (CDDP) and radiation, to overcome chemo- and radio-resistance. We demonstrate that Agave extract induces a marked decrease of Yes Associated Protein (YAP) and Tafazzin (TAZ) mRNA and protein expression upon treatment. We propose an initial mechanism of action in which Agave induces YAP/TAZ protein degradation, followed by a secondary event whereby Agave inhibits YAP/TAZ transcription, effectively deregulating the Nuclear Factor kappa B (NF-\u3baB) p65:p50 heterodimers responsible for transcriptional induction of YAP and TAZ
Emerging mechanisms underpinning neurophysiological impairments in C9ORF72 repeat expansion-mediated amyotrophic lateral sclerosis/frontotemporal dementia
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are characterized by degeneration of upper and lower motor neurons and neurons of the prefrontal cortex. The emergence of the C9ORF72 hexanucleotide repeat expansion mutation as the leading genetic cause of ALS and FTD has led to a progressive understanding of the multiple cellular pathways leading to neuronal degeneration. Disturbances in neuronal function represent a major subset of these mechanisms and because such functional perturbations precede degeneration, it is likely that impaired neuronal function in ALS/FTD plays an active role in pathogenesis. This is supported by the fact that ALS/FTD patients consistently present with neurophysiological impairments prior to any apparent degeneration. In this review we summarize how the discovery of the C9ORF72 repeat expansion mutation has contributed to the current understanding of neuronal dysfunction in ALS/FTD. Here, we discuss the impact of the repeat expansion on neuronal function in relation to intrinsic excitability, synaptic, network and ion channel properties, highlighting evidence of conserved and divergent pathophysiological impacts between cortical and motor neurons and the influence of non-neuronal cells. We further highlight the emerging association between these dysfunctional properties with molecular mechanisms of the C9ORF72 mutation that appear to include roles for both, haploinsufficiency of the C9ORF72 protein and aberrantly generated dipeptide repeat protein species. Finally, we suggest that relating key pathological observations in C9ORF72 repeat expansion ALS/FTD patients to the mechanistic impact of the C9ORF72 repeat expansion on neuronal function will lead to an improved understanding of how neurophysiological dysfunction impacts upon pathogenesis
Amyotrophic lateral sclerosis-associated mutant VAPBP56S perturbs calcium homeostasis to disrupt axonal transport of mitochondria
A proline-to-serine substitution at position 56 in the gene encoding vesicle-associated membrane protein-associated protein B (VAPB; VAPBP56S) causes some dominantly inherited familial forms of motor neuron disease, including amyotrophic lateral sclerosis (ALS) type-8. Here, we show that expression of ALS mutant VAPBP56S but not wild-type VAPB in neurons selectively disrupts anterograde axonal transport of mitochondria. VAPBP56S-induced disruption of mitochondrial transport involved reductions in the frequency, velocity and persistence of anterograde mitochondrial movement. Anterograde axonal transport of mitochondria is mediated by the microtubule-based molecular motor kinesin-1. Attachment of kinesin-1 to mitochondria involves the outer mitochondrial membrane protein mitochondrial Rho GTPase-1 (Miro1) which acts as a sensor for cytosolic calcium levels ([Ca2+]c); elevated [Ca2+]c disrupts mitochondrial transport via an effect on Miro1. To gain insight into the mechanisms underlying the VAPBP56S effect on mitochondrial transport, we monitored [Ca2+]c levels in VAPBP56S-expressing neurons. Expression of VAPBP56S but not VAPB increased resting [Ca2+]c and this was associated with a reduction in the amounts of tubulin but not kinesin-1 that were associated with Miro1. Moreover, expression of a Ca2+ insensitive mutant of Miro1 rescued defective mitochondrial axonal transport and restored the amounts of tubulin associated with the Miro1/kinesin-1 complex to normal in VAPBP56S-expressing cells. Our results suggest that ALS mutant VAPBP56S perturbs anterograde mitochondrial axonal transport by disrupting Ca2+ homeostasis and effecting the Miro1/kinesin-1 interaction with tubulin
Translating SOD1 gene silencing towards the clinic: A highly efficacious, off-target free and biomarker-supported strategy for familial ALS
Twenty per cent of familial amyotrophic lateral sclerosis (fALS) cases are caused by mutations in
the gene encoding human cytosolic Cu/Zn superoxide dismutase (hSOD1). Efficient translation of
the therapeutic potential of interfering RNA (RNAi) for the treatment of SOD1-ALS patients
requires the development of vectors that are free of significant off-target effects and with reliable
biomarkers to discern sufficient target engagement and correct dosing. Using adeno-associated virus
serotype 9 to deliver RNAi against hSOD1 in the SOD1G93A mouse model, we found that intrathecal
injection of the therapeutic vector via the cisterna magna delayed onset of disease, decreased motor
neuron death at end stage by up to 88% and prolonged the median survival of SOD1G93A mice by up
to 42%. To our knowledge this is the first report to demonstrate no significant off-target effects
linked to hSOD1 silencing, providing further confidence in the specificity of this approach. We also
report the measurement of cerebrospinal fluid (CSF) hSOD1 protein levels as a biomarker of
effective dosing and efficacy of hSOD1 knockdown. Together, these data provide further confidence
in the safety of the clinical therapeutic vector. The CSF biomarker will be a useful measure of
biological activity for translation into human clinical trials
Directly converted astrocytes retain the ageing features of the donor fibroblasts and elucidate the astrocytic contribution to human CNS health and disease
Astrocytes are highly specialised cells, responsible for CNS homeostasis and neuronal activity. Lack of human in vitro systems able to recapitulate the functional changes affecting astrocytes during ageing represents a major limitation to studying mechanisms and potential therapies aiming to preserve neuronal health. Here, we show that induced astrocytes from fibroblasts donors in their childhood or adulthood display age‐related transcriptional differences and functionally diverge in a spectrum of age‐associated features, such as altered nuclear compartmentalisation, nucleocytoplasmic shuttling properties, oxidative stress response and DNA damage response. Remarkably, we also show an age‐related differential response of induced neural progenitor cells derived astrocytes (iNPC‐As) in their ability to support neurons in co‐culture upon pro‐inflammatory stimuli. These results show that iNPC‐As are a renewable, readily available resource of human glia that retain the age‐related features of the donor fibroblasts, making them a unique and valuable model to interrogate human astrocyte function over time in human CNS health and disease
Necdin Protects Embryonic Motoneurons from Programmed Cell Death
NECDIN belongs to the type II Melanoma Associated Antigen Gene Expression gene family and is located in the Prader-Willi Syndrome (PWS) critical region. Necdin-deficient mice develop symptoms of PWS, including a sensory and motor deficit. However, the mechanisms underlying the motor deficit remain elusive. Here, we show that the genetic ablation of Necdin, whose expression is restricted to post-mitotic neurons in the spinal cord during development, leads to a loss of 31% of specified motoneurons. The increased neuronal loss occurs during the period of naturally-occurring cell death and is not confined to specific pools of motoneurons. To better understand the role of Necdin during the period of programmed cell death of motoneurons we used embryonic spinal cord explants and primary motoneuron cultures from Necdin-deficient mice. Interestingly, while Necdin-deficient motoneurons present the same survival response to neurotrophic factors, we demonstrate that deletion of Necdin leads to an increased susceptibility of motoneurons to neurotrophic factor deprivation. We show that by neutralizing TNFα this increased susceptibility of Necdin-deficient motoneurons to trophic factor deprivation can be reduced to the normal level. We propose that Necdin is implicated through the TNF-receptor 1 pathway in the developmental death of motoneurons
- …