1,568 research outputs found
Caveolin-1 protects B6129 mice against Helicobacter pylori gastritis.
Caveolin-1 (Cav1) is a scaffold protein and pathogen receptor in the mucosa of the gastrointestinal tract. Chronic infection of gastric epithelial cells by Helicobacter pylori (H. pylori) is a major risk factor for human gastric cancer (GC) where Cav1 is frequently down-regulated. However, the function of Cav1 in H. pylori infection and pathogenesis of GC remained unknown. We show here that Cav1-deficient mice, infected for 11 months with the CagA-delivery deficient H. pylori strain SS1, developed more severe gastritis and tissue damage, including loss of parietal cells and foveolar hyperplasia, and displayed lower colonisation of the gastric mucosa than wild-type B6129 littermates. Cav1-null mice showed enhanced infiltration of macrophages and B-cells and secretion of chemokines (RANTES) but had reduced levels of CD25+ regulatory T-cells. Cav1-deficient human GC cells (AGS), infected with the CagA-delivery proficient H. pylori strain G27, were more sensitive to CagA-related cytoskeletal stress morphologies ("humming bird") compared to AGS cells stably transfected with Cav1 (AGS/Cav1). Infection of AGS/Cav1 cells triggered the recruitment of p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1) to Cav1 and counteracted CagA-induced cytoskeletal rearrangements. In human GC cell lines (MKN45, N87) and mouse stomach tissue, H. pylori down-regulated endogenous expression of Cav1 independently of CagA. Mechanistically, H. pylori activated sterol-responsive element-binding protein-1 (SREBP1) to repress transcription of the human Cav1 gene from sterol-responsive elements (SREs) in the proximal Cav1 promoter. These data suggested a protective role of Cav1 against H. pylori-induced inflammation and tissue damage. We propose that H. pylori exploits down-regulation of Cav1 to subvert the host's immune response and to promote signalling of its virulence factors in host cells
Body Temperature Patterns and Rhythmicity in Free-Ranging Subterranean Damaraland Mole-Rats, Fukomys damarensis
Body temperature (Tb) is an important physiological component that affects endotherms from the cellular to whole organism level, but measurements of Tb in the field have been noticeably skewed towards heterothermic species and seasonal comparisons are largely lacking. Thus, we investigated patterns of Tb patterns in a homeothermic, free-ranging small mammal, the Damaraland mole-rat (Fukomys damarensis) during both the summer and winter. Variation in Tb was significantly greater during winter than summer, and greater among males than females. Interestingly, body mass had only a small effect on variation in Tb and there was no consistent pattern relating ambient temperature to variation in Tb. Generally speaking, it appears that variation in Tb patterns varies between seasons in much the same way as in heterothermic species, just to a lesser degree. Both cosinor analysis and Fast Fourier Transform analysis revealed substantial individual variation in Tb rhythms, even within a single colony. Some individuals had no Tb rhythms, while others appeared to exhibit multiple rhythms. These data corroborate previous laboratory work showing multiplicity of rhythms in mole-rats and suggest the variation seen in the laboratory is a true indicator of the variation seen in the wild
Communally breeding bats use physiological and behavioural adjustments to optimise daily energy expenditure
Small endotherms must change roosting and thermoregulatory behaviour in response to changes in ambient conditions if they are to achieve positive energy balance. In social species, for example many bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, and also by social thermoregulation. Direct measurements of daily fluctuations in metabolic rates in response to ambient and behavioural variables in the field have not been technologically feasible until recently. During different reproductive periods, we investigated the relationships between ambient temperature, group size and energy expenditure in wild maternity colonies of Bechstein’s bats (Myotis bechsteinii). Bats used behavioural and physiological adjustments to regulate energy expenditure. Whether bats maintained normothermia or used torpor, the number of bats in the roosts as well changed with reproductive status and ambient temperature. During pregnancy and lactation, bats remained mostly normothermic and daily group sizes were relatively large, presumably to participate in the energetic benefits of social thermoregulation. In contrast, smaller groups were formed on days when bats used torpor, which occurred mostly during the post-lactation period. Thus, we were able to demonstrate on wild animals under natural conditions the significance of behavioural and physiological flexibility for optimal thermoregulatory behaviour in small endotherms
Caracterización de pacientes con mielopatía espondilótica cervical intervenidos por disectomía anterior
Introduction: cervical spondylotic myelopathy is a common disease, which accounts for a quarter of all upper-limb paresthesia. Anterior graft discectomy is one of the most widely used surgical techniques in the world to treat this disease.Objective: to characterize patients with cervical spondylotic myelopathy who underwent surgery using the anterior discectomy with graft technique.Methods: a retrospective, descriptive, longitudinal study was conducted in 35 patients with cervical spondylotic myelopathy who underwent surgery using the anterior graft discectomy technique at “Lucia Iñiguez Landín” Clinical Surgical Teaching Hospital from January 2017 to December 2019. The variables studied were: age, sex, race, personal pathological history, signs and symptoms (before the surgery), cervical level affected, sequelae and complications.Results: male patients predominated (59,9 %), with ages between 45 and 60 years (45,71 %) and with personal pathological history of obesity (40 %). The prevailing clinical manifestations before surgery were hyperreflexia (65,71 %) and paresthesia (62,85 %). The most affected cervical segment was C5-C7 (91,42 %). The main complications were generalized hyperreflexia (17,14 %) and pain (8,57 %).Conclusions: patients with cervical spondylotic myelopathy surgically treated by the anterior discectomy with graft technique were mostly male, in ages after the fourth decade of life. Patients presented hyperreflexia before the surgery, and could develop generalized hyperreflexia as a complication.Introducción: la mielopatía espondilótica cervical es una enfermedad frecuente, que representa la cuarta parte de las parestesias en miembros superiores. La disectomía anterior con injerto es una de las técnicas quirúrgicas más utilizadas en el mundo para tratar esta enfermedad.Objetivo: Caracterizar los pacientes con mielopatía espondilótica cervical intervenidos quirúrgicamente por la técnica disectomía anterior con injerto.Método: Se realizó un estudio observacional, descriptivo, longitudinal retrospectivo en 35 pacientes con mielopatía espondilótica cervical intervenidos quirúrgicamente por la técnica de disectomía anterior con injerto en el Hospital Clínico Quirúrgico Docente “Lucia Iñiguez Landín” en el período de enero del 2017 a diciembre del 2019. Las variables estudiadas fueron: edad, sexo, color de piel, antecedentes patológicos personales, signos y síntomas (antes de la operación), nivel cervical afectado, secuelas y complicaciones.Resultados: Se encontró predominio de pacientes masculinos (59,9 %), con edades entre 45 y 60 años (45,71 %) y con antecedentes patológicos personales de obesidad (40 %). Las manifestaciones clínicas que predominaron antes de la intervención quirúrgica fueron la hiperreflexia (65,71 %) y la parestesia (62,85 %). El segmento cervical más afectado fue C5-C7 (91,42 %). Las principales complicaciones fueron la hiperreflexia generalizada (17,14 %) y el dolor (8,57).Conclusiones: los pacientes con mielopatía espondilótica cervical intervenidos quirúrgicamente por la técnica disectomía anterior con injerto fueron de sexo masculino en su mayoría, con edades pasadas de la cuarta década de vida. Los pacientes presentaron hiperreflexia antes de la operación, pudiendo desarrollar hiperreflexia generalizada como complicación
A sensing mechanism for the detection of carbon nanotubes using selective photoluminescent probes based on ionic complexes with organic dyes
The multifunctional properties of carbon nanotubes (CNTs) make them a powerful platform for unprecedented innovations in a variety of practical applications. As a result of the surging growth of nanotechnology, nanotubes present a potential problem as an environmental pollutant, and as such, an efficient method for their rapid detection must be established. Here, we propose a novel type of ionic sensor complex for detecting CNTs – an organic dye that responds sensitively and selectively to CNTs with a photoluminescent signal. The complexes are formed through Coulomb attractions between dye molecules with uncompensated charges and CNTs covered with an ionic surfactant in water. We demonstrate that the photoluminescent excitation of the dye can be transferred to the nanotubes, resulting in selective and strong amplification (up to a factor of 6) of the light emission from the excitonic levels of CNTs in the near-infrared spectral range, as experimentally observed via excitation-emission photoluminescence (PL) mapping. The chirality of the nanotubes and the type of ionic surfactant used to disperse the nanotubes both strongly affect the amplification; thus, the complexation provides sensing selectivity towards specific CNTs. Additionally, neither similar uncharged dyes nor CNTs covered with neutral surfactant form such complexes. As model organic molecules, we use a family of polymethine dyes with an easily tailorable molecular structure and, consequently, tunable absorbance and PL characteristics. This provides us with a versatile tool for the controllable photonic and electronic engineering of an efficient probe for CNT detection
Meta-analytic approach to the accurate prediction of secreted virulence effectors in gram-negative bacteria
<p>Abstract</p> <p>Background</p> <p>Many pathogens use a type III secretion system to translocate virulence proteins (called effectors) in order to adapt to the host environment. To date, many prediction tools for effector identification have been developed. However, these tools are insufficiently accurate for producing a list of putative effectors that can be applied directly for labor-intensive experimental verification. This also suggests that important features of effectors have yet to be fully characterized.</p> <p>Results</p> <p>In this study, we have constructed an accurate approach to predicting secreted virulence effectors from Gram-negative bacteria. This consists of a support vector machine-based discriminant analysis followed by a simple criteria-based filtering. The accuracy was assessed by estimating the average number of true positives in the top-20 ranking in the genome-wide screening. In the validation, 10 sets of 20 training and 20 testing examples were randomly selected from 40 known effectors of <it>Salmonella enterica </it>serovar Typhimurium LT2. On average, the SVM portion of our system predicted 9.7 true positives from 20 testing examples in the top-20 of the prediction. Removal of the N-terminal instability, codon adaptation index and ProtParam indices decreased the score to 7.6, 8.9 and 7.9, respectively. These discrimination features suggested that the following characteristics of effectors had been uncovered: unstable N-terminus, non-optimal codon usage, hydrophilic, and less aliphathic. The secondary filtering process represented by coexpression analysis and domain distribution analysis further refined the average true positive counts to 12.3. We further confirmed that our system can correctly predict known effectors of <it>P. syringae </it>DC3000, strongly indicating its feasibility.</p> <p>Conclusions</p> <p>We have successfully developed an accurate prediction system for screening effectors on a genome-wide scale. We confirmed the accuracy of our system by external validation using known effectors of <it>Salmonella </it>and obtained the accurate list of putative effectors of the organism. The level of accuracy was sufficient to yield candidates for gene-directed experimental verification. Furthermore, new features of effectors were revealed: non-optimal codon usage and instability of the N-terminal region. From these findings, a new working hypothesis is proposed regarding mechanisms controlling the translocation of virulence effectors and determining the substrate specificity encoded in the secretion system.</p
Dermatoglyphic patterns in children with chronic constipation
Analysis of the fine ridge configurations on the digits of the palms and soles (dermatoglyphics) may sometimes help in the diagnoses of certain medical disorders. Dermatoglyphic patterns have been reported to be associated with congenital anomalies, such as congenital heart disease, duodenal ulcer, abdominal pain, and constipation. The palmar dermatoglyphic patterns of 77 children with constipation (39 functional and 38 organic constipation) were recorded. The control group consisted of 84 children with inguinal hernia. Those patients with at least one arch identified on any digit of either hand were termed arch positive. There was no significant correlation between arch positivity and constipation (functional or organic), or inguinal hernia (chi square, P =0.9211). Therefore, the presence of palmar arches cannot be used as a screening device for children with chronic constipation, especially of organic etiology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44424/1/10620_2005_Article_BF02285186.pd
Dopamine Agonists and their risk to induce psychotic episodes in Parkinson's disease: a case-control study
<p>Abstract</p> <p>Background</p> <p>Psychosis is rare in untreated patients with Parkinson's disease (PD) but the prevalence rises to 40% during dopaminergic treatment. So far, no systematic comparison of the psychogenic potential of different dopaminergic drugs had been performed.</p> <p>Methods</p> <p>Eighty PD patients with psychotic episodes were compared to an age-matched control group of PD patients without psychotic episodes (n = 120) in a cross-sectional retrospective study.</p> <p>Results</p> <p>We found a positive correlation between psychotic episodes and dementia, number of concomitant medication, and pergolide intake. Odds ratio calculation confirmed the association with dementia. With respect to dopaminergic treatment, pergolide showed the highest odds ratio, levodopa the lowest. An adjusted logistic regression model confirmed the strong association with psychotic episodes and pergolide and no association with levodopa (adjusted odds ratio 2.01 and 0.11, respectively).</p> <p>Conclusion</p> <p>The analysis indicates that dementia and concomitant medication are factors in PD associated with psychotic symptoms. Furthermore, different dopaminergic drugs showed markedly different associations with psychotic symptoms</p
Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector
The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV
Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in ppcollisions at √s=8TeV
The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3fb−1of data collected in proton–proton collisions at √s=8TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeVto 900 GeV, and a long-lived neutral particle mass from 10 GeVto 150 GeV
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