476 research outputs found

    Lysosomal cholesterol accumulation sensitizes to acetaminophen hepatotoxicity by impairing mitophagy.

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    The role of lysosomes in acetaminophen (APAP) hepatotoxicity is poorly understood. Here, we investigated the impact of genetic and drug-induced lysosomal cholesterol (LC) accumulation in APAP hepatotoxicity. Acid sphingomyelinase (ASMase)(-/-) mice exhibit LC accumulation and higher mortality after APAP overdose compared to ASMase(+/+) littermates. ASMase(-/-) hepatocytes display lower threshold for APAP-induced cell death and defective fusion of mitochondria-containing autophagosomes with lysosomes, which decreased mitochondrial quality control. LC accumulation in ASMase(+/+) hepatocytes caused by U18666A reproduces the susceptibility of ASMase(-/-) hepatocytes to APAP and the impairment in the formation of mitochondria-containing autolysosomes. LC extraction by 25-hydroxycholesterol increased APAP-mediated mitophagy and protected ASMase(-/-) mice and hepatocytes against APAP hepatotoxicity, effects that were reversed by chloroquine to disrupt autophagy. The regulation of LC by U18666A or 25-hydroxycholesterol did not affect total cellular sphingomyelin content or its lysosomal distribution. Of relevance, amitriptyline-induced ASMase inhibition in human hepatocytes caused LC accumulation, impaired mitophagy and increased susceptibility to APAP. Similar results were observed upon glucocerebrosidase inhibition by conduritol ÎČ-epoxide, a cellular model of Gaucher disease. These findings indicate that LC accumulation determines susceptibility to APAP hepatotoxicity by modulating mitophagy, and imply that genetic or drug-mediated ASMase disruption sensitizes to APAP-induced liver injury

    Differential susceptibility to obesity between male, female and ovariectomized female mice

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    All authors are with the Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas, USABackground: The prevalence of obesity has increased dramatically. A direct comparison in the predisposition to obesity between males, premenopausal females, and postmenopausal females with various caloric intakes has not been made. To determine the effects of sex and ovarian hormones on the susceptibility to obesity, we conducted laboratory studies with mice. To eliminate confounders that can alter body weight gain, such as age and food consumption; we used mice with the same age and controlled the amount of calories they consumed. -- Methods: We determined sex-specific susceptibility to obesity between male, non-ovariectomized female, and ovariectomized female mice. To compare susceptibility to gaining body weight between males and females, animals from each sex were exposed to either a 30% calorie-restricted, low-fat (5% fat), or high-fat (35% fat) diet regimen. To establish the role of ovarian hormones in weight gain, the ovaries were surgically removed from additional female mice, and then were exposed to the diets described above. Percent body fat and percent lean mass in the mice were determined by dual energy x-ray absorptiometry (DEXA). -- Results: In all three diet categories, male mice had a greater propensity of gaining body weight than female mice. However, ovariectomy eliminated the protection of female mice to gaining weight; in fact, ovariectomized female mice mimicked male mice in their susceptibility to weight gain. In summary, results show that male mice are more likely to become obese than female mice and that the protection against obesity in female mice is eliminated by ovariectomy. -- Conclusion: Understanding metabolic differences between males and females may allow the discovery of better preventive and treatment strategies for diseases associated with body weight such as cancer and cardiovascular disease.Nutritional [email protected]

    Characterization of a jelly of Calendula officinalis L. at 1% for stomatological use

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    Introducción: La Calendula officinalis L. es una de las especies vegetales mås utilizadas en el tratamiento de enfermedades periodontales. Objetivo: Determinar preliminarmente los paråmetros de calidad de la jalea de Calendula officinalis L. al 1% para uso estomatológico. Métodos: Se elaboraron 18 formulaciones utilizando como agente gelificante carboximetilcelulosa (CMC) e hidroxipropilmetilcelulosa (HPMC), empleando el método de incorporación. A las mismas se le determinaron los paråmetros de calidad y se seleccionaron las cuatro con mejores paråmetros tecnológicos para evaluar el grado de aceptación sensorial por parte de un comité de expertos. Resultados: Las formulaciones con HPMC fueron las que presentaron mejores características organolépticas y pH aceptable para su aplicación sobre la mucosa bucal; así como un årea de extensibilidad óptimo, lo que permitió que fueran seleccionadas para realizar el anålisis sensorial. Conclusión: Se establecieron preliminarmente los paråmetros de calidad de la jalea Calendula officinalis L. al 1% siendo seleccionada la formulación codificada como HPMC 6 por presentar olor característico al extracto blando, color åmbar tenue, homogéneo y con brillo, sabor agradable, no presentar grumos ni arenosidad, årea de extensibilidad de 66.96±0.91cm2, pH de 4.9 y mayor aceptabilidad sensorial.Introduction: Calendula officinalis L. is one of the plant species most used in the treatment of periodontal diseases. Objective: To determine preliminarily the quality parameters of Calendula officinalis L. jelly at 1% for stomatological use. Methods: 18 formulations were prepared using carboxymethylcellulose (CMC) and hydroxypropylmethylcellulose (HPMC) as the gelling agent, using the incorporation method. The quality parameters were determined selecting the four formulations with better technological parameters to evaluate sensory acceptance by a committee of experts. Results: The HPMC formulations presented better organoleptic characteristics and acceptable pH for its application on the buccal mucosa; as well as an area of optimal extensibility, which allowed them to be selected to carry out the sensory analysis. Conclusion: The quality parameters of the Calendula officinalis L. 1% jelly were preliminarily established the formulation encoded as HPMC 6 is selected for presenting characteristic odor to the soft extract, amber color subdued, homogeneous and glossy, pleasant taste, no lumps or grit, area of extensibility of 66.96 ± 0.91cm2, pH of 4.9 and greater sensory acceptability

    Experimental observation of the optical spin-orbit torque

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    Spin polarized carriers electrically injected into a magnet from an external polarizer can exert a spin transfer torque (STT) on the magnetization. The phe- nomenon belongs to the area of spintronics research focusing on manipulating magnetic moments by electric fields and is the basis of the emerging technologies for scalable magnetoresistive random access memories. In our previous work we have reported experimental observation of the optical counterpart of STT in which a circularly polarized pump laser pulse acts as the external polarizer, allowing to study and utilize the phenomenon on several orders of magnitude shorter timescales than in the electric current induced STT. Recently it has been theoretically proposed and experimentally demonstrated that in the absence of an external polarizer, carriers in a magnet under applied electric field can develop a non-equilibrium spin polarization due to the relativistic spin-orbit coupling, resulting in a current induced spin-orbit torque (SOT) acting on the magnetization. In this paper we report the observation of the optical counterpart of SOT. At picosecond time-scales, we detect excitations of magnetization of a ferromagnetic semiconductor (Ga,Mn)As which are independent of the polarization of the pump laser pulses and are induced by non-equilibrium spin-orbit coupled photo-holes.Comment: 4 figure, supplementary information. arXiv admin note: text overlap with arXiv:1101.104

    Anticoagulant therapy for splanchnic vein thrombosis: an individual patient data meta-analysis

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    Robust evidence on the optimal management of splanchnic vein thrombosis (SVT) is lacking. We conducted an individual-patient meta-analysis to evaluate the effectiveness and safety of anticoagulation for SVT. Medline, Embase, and clincaltrials.gov were searched up to June 2021 for prospective cohorts or randomized clinical trials including patients with SVT. Data from individual datasets were merged, and any discrepancy with published data was resolved by contacting study authors. Three studies of a total of 1635 patients were included. Eighty-five percent of patients received anticoagulation for a median duration of 316 days (range, 1-730 days). Overall, incidence rates for recurrent venous thromboembolism (VTE), major bleeding, and mortality were 5.3 per 100 patient-years (p-y; 95% confidence interval [CI], 5.1-5.5), 4.4 per 100 p-y (95% CI, 4.2-4.6), and 13.0 per 100 p-y (95% CI, 12.4-13.6), respectively. The incidence rates of all outcomes were lower during anticoagulation and higher after treatment discontinuation or when anticoagulation was not administered. In multivariable analysis, anticoagulant treatment appeared to be associated with a lower risk of recurrent VTE (hazard ratio [HR], 0.42; 95% CI, 0.27-0.64), major bleeding (HR, 0.47; 95% CI, 0.30-0.74), and mortality (HR, 0.23; 95% CI, 0.17-0.31). Results were consistent in patients with cirrhosis, solid cancers, myeloproliferative neoplasms, unprovoked SVT, and SVT associated with transient or persistent nonmalignant risk factors. In patients with SVT, the risk of recurrent VTE and major bleeding is substantial. Anticoagulant treatment is associated with reduced risk of both outcomes. © 2022 by The American Society of Hematology

    Aversive Learning in Honeybees Revealed by the Olfactory Conditioning of the Sting Extension Reflex

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    Invertebrates have contributed greatly to our understanding of associative learning because they allow learning protocols to be combined with experimental access to the nervous system. The honeybee Apis mellifera constitutes a standard model for the study of appetitive learning and memory since it was shown, almost a century ago, that bees learn to associate different sensory cues with a reward of sugar solution. However, up to now, no study has explored aversive learning in bees in such a way that simultaneous access to its neural bases is granted. Using odorants paired with electric shocks, we conditioned the sting extension reflex, which is exhibited by harnessed bees when subjected to a noxious stimulation. We show that this response can be conditioned so that bees learn to extend their sting in response to the odorant previously punished. Bees also learn to extend the proboscis to one odorant paired with sugar solution and the sting to a different odorant paired with electric shock, thus showing that they can master both appetitive and aversive associations simultaneously. Responding to the appropriate odorant with the appropriate response is possible because two different biogenic amines, octopamine and dopamine subserve appetitive and aversive reinforcement, respectively. While octopamine has been previously shown to substitute for appetitive reinforcement, we demonstrate that blocking of dopaminergic, but not octopaminergic, receptors suppresses aversive learning. Therefore, aversive learning in honeybees can now be accessed both at the behavioral and neural levels, thus opening new research avenues for understanding basic mechanisms of learning and memory

    Validation of bioelectrical impedance analysis for body composition assessment in children with obesity aged 8-14y

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    BACKGROUND & AIMS: The aim was to generate a predictive equation to assess body composition (BC) in children with obesity using bioimpedance (BIA), and avoid bias produced by different density levels of fat free mass (FFM) in this population. METHODS: This was a cross-sectional validation study using baseline data from a randomized intervention trial to treat childhood obesity. Participants were 8 to 14y (n = 315), underwent assessments on anthropometry and BC through Air Displacement Plethysmography (ADP), Dual X-Ray Absorptiometry and BIA. They were divided into a training (n = 249) and a testing subset (n = 66). In addition, the testing subset underwent a total body water assessment using deuterium dilution, and thus obtained results for the 4-compartment model (4C). A new equation to estimate FFM was created from the BIA outputs by comparison to a validated model of ADP adjusted by FFM density in the training subset. The equation was validated against 4C in the testing subset. As reference, the outputs from the BIA device were also compared to 4C. RESULTS: The predictive equation reduced the bias from the BIA outputs from 14.1% (95%CI: 12.7, 15.4) to 4.6% (95%CI: 3.8, 5.4) for FFM and from 18.4% (95%CI: 16.9, 19.9) to 6.4% (95% CI: 5.3, 7.4) for FM. Bland-Altman plots revealed that the new equation significantly improved the agreement with 4C; furthermore, the observed trend to increase the degree of bias with increasing FM and FFM also disappeared. CONCLUSION: The new predictive equation increases the precision of BC assessment using BIA in children with obesity

    MYO9B polymorphisms in multiple sclerosis

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    "Single-nucleotide polymorphisms (SNPs) in the 30 region of myosin IXB (MYO9B) gene have recently been reported to associate with different inflammatory or autoimmune diseases. We monitored for the association of MYO9B variants to multiple sclerosis (MS) in four Northern European populations. First, 18 SNPs including 6 SNPs with previous evidence for association to immune disorders, were tested in 730 Finnish MS families, but no linkage or family-based association was observed. To ensure the power to detect variants with a modest effect size, we further analyzed 10 variants in 899 Finnish cases and 1325 controls, and in a total of 1521 cases and 1476 controls from Denmark, Norway and Sweden, but found no association. Our results thereby do not support a major function of the tested MYO9B variants in MS. European Journal of Human Genetics (2009) 17, 840-843; doi: 10.1038/ejhg.2008.251; published online 14 January 2009""Single-nucleotide polymorphisms (SNPs) in the 30 region of myosin IXB (MYO9B) gene have recently been reported to associate with different inflammatory or autoimmune diseases. We monitored for the association of MYO9B variants to multiple sclerosis (MS) in four Northern European populations. First, 18 SNPs including 6 SNPs with previous evidence for association to immune disorders, were tested in 730 Finnish MS families, but no linkage or family-based association was observed. To ensure the power to detect variants with a modest effect size, we further analyzed 10 variants in 899 Finnish cases and 1325 controls, and in a total of 1521 cases and 1476 controls from Denmark, Norway and Sweden, but found no association. Our results thereby do not support a major function of the tested MYO9B variants in MS. European Journal of Human Genetics (2009) 17, 840-843; doi: 10.1038/ejhg.2008.251; published online 14 January 2009""Single-nucleotide polymorphisms (SNPs) in the 30 region of myosin IXB (MYO9B) gene have recently been reported to associate with different inflammatory or autoimmune diseases. We monitored for the association of MYO9B variants to multiple sclerosis (MS) in four Northern European populations. First, 18 SNPs including 6 SNPs with previous evidence for association to immune disorders, were tested in 730 Finnish MS families, but no linkage or family-based association was observed. To ensure the power to detect variants with a modest effect size, we further analyzed 10 variants in 899 Finnish cases and 1325 controls, and in a total of 1521 cases and 1476 controls from Denmark, Norway and Sweden, but found no association. Our results thereby do not support a major function of the tested MYO9B variants in MS. European Journal of Human Genetics (2009) 17, 840-843; doi: 10.1038/ejhg.2008.251; published online 14 January 2009"Peer reviewe

    Predictive model of pheochromocytoma based on the imaging features of the adrenal tumours

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    The purpose of our study was to develop a predictive model to rule out pheochromocytoma among adrenal tumours, based on unenhanced computed tomography (CT) and/or magnetic resonance imaging (MRI) features. We performed a retrospective multicentre study of 1131 patients presenting with adrenal lesions including 163 subjects with histological confirmation of pheochromocytoma (PHEO), and 968 patients showing no clinical suspicion of pheochromocytoma in whom plasma and/or urinary metanephrines and/or catecholamines were within reference ranges (non-PHEO). We found that tumour size was significantly larger in PHEO than non-PHEO lesions (44.3 +/- 33.2 versus 20.6 +/- 9.2 mm respectively; P < 0.001). Mean unenhanced CT attenuation was higher in PHEO (52.4 +/- 43.1 versus 4.7 +/- 17.9HU; P < 0.001). High lipid content in CT was more frequent among non-PHEO (83.6% versus 3.8% respectively; P < 0.001); and this feature alone had 83.6% sensitivity and 96.2% specificity to rule out pheochromocytoma with an area under the receiver operating characteristics curve (AUC-ROC) of 0.899. The combination of high lipid content and tumour size improved the diagnostic accuracy (AUC-ROC 0.961, sensitivity 88.1% and specificity 92.3%). The probability of having a pheochromocytoma was 0.1% for adrenal lesions smaller than 20 mm showing high lipid content in CT. Ninety percent of non-PHEO presented loss of signal in the out of phase MRI sequence compared to 39.0% of PHEO (P < 0.001), but the specificity of this feature for the diagnosis of non-PHEO lesions low. In conclusion, our study suggests that sparing biochemical screening for pheochromocytoma might be reasonable in patients with adrenal lesions smaller than 20 mm showing high lipid content in the CT scan, if there are no typical signs and symptoms of pheochromocytoma
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