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1.
Clin Rheumatol ; 43(8): 2445-2452, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38877374

RESUMEN

OBJECTIVE: Rheumatoid arthritis can be classified according to ACPA and RF status. ACPA status may be associated with other pathophysiological differences, e.g., the cytokines driving inflammation. Obesity influences the course of RA, likely involving leptin; the exact mechanisms are not completely understood. This study investigates BMI influence on RA cytokine profiles and the possibility of predicting ACPA status and disease activity measured by Power-Doppler sonography (PDS). METHODS: Patients were examined using a multi-biomarker disease assay and PDS examination of wrists and MCP and PIP joints and stratified according to ACPA status and BMI, using prediction precision to determine BMI cutoff. Analysis was performed using elastic net regularization of logistic and multiple regression. We then attempted to predict ACPA status/PDS activity based on a bootstrap approach. RESULTS: A total of 120 measurements from 95 patients were performed. ACPA status prediction peaked at BMI 26 kg/m2, with AUC 0.82. PDS activity prediction had a mean average error of < 1.6 PDS points for all groups. In obese patients, cytokine profiles appear to align in ACPA-positive and -negative patients, with leptin playing a greater role in predicting PDS activity, but with some remaining differences. CONCLUSION: When stratified according to BMI, cytokine patterns can predict ACPA status and PDS activity in RA with a high degree of precision. This indicates that studies into the pathophysiology of RA should take BMI into account, to differentiate between disease- and obesity-associated phenomena. The underlying pathological processes of ACPA-negative and -positive RA appear different. Multi-cytokine evaluations may provide a deeper understanding of disease processes. Key Points • A multi-cytokine approach combined with ultrasonography and modern mathematical methods can contribute to a deeper understanding of the relationship between systemic and joint inflammation. • BMI influences cytokine profiles in rheumatoid arthritis and appears to "override" disease-specific processes. • Using cytokines only, and adjusting for BMI, it is possible to predict the ACPA status and joint inflammation with considerable precision.


Asunto(s)
Anticuerpos Antiproteína Citrulinada , Artritis Reumatoide , Índice de Masa Corporal , Citocinas , Ultrasonografía Doppler , Humanos , Artritis Reumatoide/sangre , Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/inmunología , Femenino , Masculino , Persona de Mediana Edad , Anticuerpos Antiproteína Citrulinada/sangre , Citocinas/sangre , Anciano , Adulto , Biomarcadores/sangre , Obesidad/sangre , Obesidad/complicaciones , Índice de Severidad de la Enfermedad , Leptina/sangre , Articulación de la Muñeca/diagnóstico por imagen
2.
Pharmacoepidemiol Drug Saf ; 32(11): 1223-1232, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37280706

RESUMEN

PURPOSE: Database heterogeneity can impact effect estimates. Harmonisation provided by common protocols and common data models (CDMs) can increase the validity of pharmacoepidemiologic research. In a case study measuring the changes in the safety and effectiveness of stroke prevention therapy after the introduction of direct oral anticoagulants (DOACs), we performed an international comparison. METHODS: Using data from Stockholm, Denmark, Scotland and Norway, harmonised with a common protocol and CDM, two calendar-based cohorts were created: 2012 and 2017. Patients with a diagnosis code of atrial fibrillation 5 years preceding the 1-year cohort window were included. DOAC, vitamin K antagonist and aspirin treatment were assessed in the 6 months prior to the start of each year while strokes and bleeds were assessed during the year. A Poisson regression generated incidence rate ratios (IRRs) to compare outcomes from 2017 to 2012 adjusted for changes in individual-level baseline characteristics. RESULTS: In 280 359 patients in the 2012 cohort and 356 779 in the 2017 cohort, treatment with OACs increased on average from 45% to 65%, while treatment with aspirin decreased from 30% to 10%. In all countries except Scotland, there were decreases in the risk of stroke and no changes in bleeding risk, after adjustment for changes in baseline characteristics. In Scotland, major bleeding (IRR 1.09, 95% confidence interval [CI] [1.00; 1.18]) and intracranial haemorrhage (IRR 1.31, 95% CI [1.13; 1.52]) increased from 2012 to 2017. CONCLUSIONS: Stroke prevention therapy improved from 2012 to 2017 with a corresponding reduction in stroke risk without increasing the risk of bleeding in all countries, except Scotland. The heterogeneity that remains after methodological harmonisation can be informative of the underlying population and database.


Asunto(s)
Fibrilación Atrial , Accidente Cerebrovascular , Humanos , Estudios Retrospectivos , Hemorragia/inducido químicamente , Hemorragia/epidemiología , Anticoagulantes , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/etiología , Accidente Cerebrovascular/prevención & control , Fibrilación Atrial/complicaciones , Fibrilación Atrial/tratamiento farmacológico , Fibrilación Atrial/epidemiología , Aspirina/uso terapéutico , Administración Oral
3.
Nat Commun ; 12(1): 3733, 2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34145226

RESUMEN

Graphene integrated photonics provides several advantages over conventional Si photonics. Single layer graphene (SLG) enables fast, broadband, and energy-efficient electro-optic modulators, optical switches and photodetectors (GPDs), and is compatible with any optical waveguide. The last major barrier to SLG-based optical receivers lies in the current GPDs' low responsivity when compared to conventional PDs. Here we overcome this by integrating a photo-thermoelectric GPD with a Si microring resonator. Under critical coupling, we achieve >90% light absorption in a ~6 µm SLG channel along a Si waveguide. Cavity-enhanced light-matter interactions cause carriers in SLG to reach ~400 K for an input power ~0.6 mW, resulting in a voltage responsivity ~90 V/W, with a receiver sensitivity enabling our GPDs to operate at a 10-9 bit-error rate, on par with mature semiconductor technology, but with a natural generation of a voltage, rather than a current, thus removing the need for transimpedance amplification, with a reduction of energy-per-bit, cost, and foot-print.

4.
Ecol Appl ; 28(4): 1003-1010, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29450936

RESUMEN

Home-range estimation is an important application of animal tracking data that is frequently complicated by autocorrelation, sampling irregularity, and small effective sample sizes. We introduce a novel, optimal weighting method that accounts for temporal sampling bias in autocorrelated tracking data. This method corrects for irregular and missing data, such that oversampled times are downweighted and undersampled times are upweighted to minimize error in the home-range estimate. We also introduce computationally efficient algorithms that make this method feasible with large data sets. Generally speaking, there are three situations where weight optimization improves the accuracy of home-range estimates: with marine data, where the sampling schedule is highly irregular, with duty cycled data, where the sampling schedule changes during the observation period, and when a small number of home-range crossings are observed, making the beginning and end times more independent and informative than the intermediate times. Using both simulated data and empirical examples including reef manta ray, Mongolian gazelle, and African buffalo, optimal weighting is shown to reduce the error and increase the spatial resolution of home-range estimates. With a conveniently packaged and computationally efficient software implementation, this method broadens the array of data sets with which accurate space-use assessments can be made.


Asunto(s)
Ecología/métodos , Algoritmos , Distribución Animal , Animales , Búfalos , Femenino , Movimiento , Rajidae
5.
Am J Transplant ; 17(12): 3060-3075, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28556588

RESUMEN

Progressive fibrosis of the interstitium is the dominant final pathway in renal destruction in native and transplanted kidneys. Over time, the continuum of molecular events following immunological and nonimmunological insults lead to interstitial fibrosis and tubular atrophy and culminate in kidney failure. We hypothesize that these insults trigger changes in DNA methylation (DNAm) patterns, which in turn could exacerbate injury and slow down the regeneration processes, leading to fibrosis development and graft dysfunction. Herein, we analyzed biopsy samples from kidney allografts collected 24 months posttransplantation and used an integrative multi-omics approach to understand the underlying molecular mechanisms. The role of DNAm and microRNAs on the graft gene expression was evaluated. Enrichment analyses of differentially methylated CpG sites were performed using GenomeRunner. CpGs were strongly enriched in regions that were variably methylated among tissues, implying high tissue specificity in their regulatory impact. Corresponding to this methylation pattern, gene expression data were related to immune response (activated state) and nephrogenesis (inhibited state). Preimplantation biopsies showed similar DNAm patterns to normal allograft biopsies at 2 years posttransplantation. Our findings demonstrate for the first time a relationship among epigenetic modifications and development of interstitial fibrosis, graft function, and inter-individual variation on long-term outcomes.


Asunto(s)
Atrofia/patología , Metilación de ADN , Fibrosis/patología , Rechazo de Injerto/genética , Fallo Renal Crónico/patología , Trasplante de Riñón/métodos , Túbulos Renales/patología , Adulto , Atrofia/metabolismo , Biomarcadores/metabolismo , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Fibrosis/metabolismo , Estudios de Seguimiento , Perfilación de la Expresión Génica , Tasa de Filtración Glomerular , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/epidemiología , Supervivencia de Injerto , Humanos , Fallo Renal Crónico/genética , Fallo Renal Crónico/cirugía , Pruebas de Función Renal , Túbulos Renales/metabolismo , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo , Trasplante Homólogo
6.
Am J Transplant ; 17(10): 2591-2600, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28326672

RESUMEN

BK polyomavirus (BKPyV) causes premature kidney transplant (KT) failure in 1-15% of patients. Because antivirals are lacking, most programs screen for BKPyV-viremia and, if positive, reduce immunosuppression. To evaluate the relationship of viremia and BKPyV-specific immunity, we examined prospectively cryopreserved plasma and peripheral blood mononuclear cells at the time of transplantation (T0) and at 6 mo (T6) and 12 mo (T12) after transplant from 28 viremic KT patients and 68 nonviremic controls matched for the transplantation period. BKPyV IgG seroprevalence was comparable between cases (89.3%) and controls (91.2%; p = 0.8635), but cases had lower antibody levels (p = 0.022) at T0. Antibody levels increased at T6 and T12 but were not correlated with viremia clearance. BKPyV-specific T cell responses to pools of overlapping 15mers (15mer peptide pool [15mP]) or immunodominant CD8 9mers (9mer peptide pool [9mP]) from the early viral gene region were not different between cases and controls at T0; however, clearance of viremia was associated with stronger 9mP responses at T6 (p = 0.042) and T12 (p = 0.048), whereas 15mP responses were not informative (T6 p = 0.359; T12 p = 0.856). BKPyV-specific T cells could be expanded in vitro from all patients after transplant, permitting identification of 78 immunodominant 9mer epitopes including 50 new ones across different HLA class I. Thus, 9mP-responses may be a novel marker of reconstituting CD8 T cell function that warrants further study as a complement of plasma BKPyV loads for guiding immunosuppression reduction.


Asunto(s)
Virus BK/fisiología , Linfocitos T CD8-positivos/inmunología , Trasplante de Riñón , Adulto , Anciano , Virus BK/aislamiento & purificación , Estudios de Casos y Controles , Estudios de Cohortes , Femenino , Humanos , Trasplante de Riñón/efectos adversos , Masculino , Persona de Mediana Edad , Viremia
7.
Leukemia ; 31(10): 2181-2190, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28119525

RESUMEN

Blinatumomab can induce a complete haematological remission in patients in 46.6% with relapsed/refractory B-precursor acute lymphoblastic leukemia (r/r ALL) resulting in a survival benefit when compared with chemotherapy. Only bone marrow blast counts before therapy have shown a weak prediction of response. Here we investigated the role of regulatory T cells (Tregs), measured by CD4/CD25/FOXP3 expression, in predicting the outcome of immunotherapy with the CD19-directed bispecific T-cell engager construct blinatumomab. Blinatumomab responders (n=22) had an average of 4.82% Tregs (confidence interval (CI): 1.79-8.34%) in the peripheral blood, whereas non-responders (n=20) demonstrated 10.25% Tregs (CI: 3.36-65.9%). All other tested markers showed either no prediction value or an inferior prediction level including blast BM counts and the classical enzyme marker lactate dehydrogenase. With a cutoff of 8.525%, Treg enumeration can identify 100% of all blinatumomab responders and exclude 70% of the non-responders. The effect is facilitated by blinatumomab-activated Tregs, leading to interleukin-10 production, resulting in suppression of T-cell proliferation and reduced CD8-mediated lysis of ALL cells. Proliferation of patients' T cells can be restored by upfront removal of Tregs. Thus, enumeration of Treg identifies r/r ALL patients with a high response rate to blinatumomab. Therapeutic removal of Tregs may convert blinatumomab non-responders to responders.


Asunto(s)
Anticuerpos Biespecíficos/uso terapéutico , Inmunoterapia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Terapia Recuperativa , Linfocitos T Reguladores/inmunología , Adolescente , Adulto , Anciano , Anticuerpos Biespecíficos/inmunología , Antígenos de Diferenciación de Linfocitos T/análisis , Línea Celular Tumoral , Ensayos Clínicos como Asunto , Citotoxicidad Inmunológica , Femenino , Humanos , Inmunofenotipificación , Interleucina-10/biosíntesis , Interleucina-10/genética , Activación de Linfocitos , Recuento de Linfocitos , Masculino , Persona de Mediana Edad , Pronóstico , Inducción de Remisión , Subgrupos de Linfocitos T/inmunología , Resultado del Tratamiento
8.
Am J Transplant ; 17(1): 11-21, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27214826

RESUMEN

In spite of reduction of rejection rates and improvement in short-term survival post-kidney transplantation, modest progress has occurred in long-term graft attrition over the years. Timely identification of molecular events that precede clinical and histopathological changes might help in early intervention and thereby increase the graft half-life. Evolution of "omics" tools has enabled systemic investigation of the influence of the whole genome, epigenome, transcriptome, proteome and microbiome on transplant function and survival. In this omics era, systemic approaches, in-depth clinical phenotyping and use of strict validation methods are the key for further understanding the complex mechanisms associated with graft function. Systems biology is an interdisciplinary holistic approach that focuses on complex and dynamic interactions within biological systems. The complexity of the human kidney transplant is unlikely to be captured by a reductionist approach. It appears essential to integrate multi-omics data that can elucidate the multidimensional and multilayered regulation of the underlying heterogeneous and complex kidney transplant model. Herein, we discuss studies that focus on genetic biomarkers, emerging technologies and systems biology approaches, which should increase the ability to discover biomarkers, understand mechanisms and stratify patients and responses post-kidney transplantation.


Asunto(s)
Marcadores Genéticos , Trasplante de Riñón , Biología de Sistemas , Genómica , Humanos , Proteómica , Transcriptoma
9.
Ecology ; 97(11): 3110-3118, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27870050

RESUMEN

Animal pollinators mediate reproduction of many plant species. Foraging theory suggests that animal pollinators exhibit preferences for common plant species in natural communities (positive frequency-dependent foraging) and temporary single-species specialization (flower constancy) during foraging bouts. Positive frequency dependence may favor common plant species; flower constancy may enhance conspecific pollen transfer particularly in rare plant species. Previous experimental studies suggest that avian pollinators are unlikely to exhibit these behaviors. We studied foraging behavior of Cape Sugarbirds (Promerops cafer), the main avian pollinator of many Protea species, using focal-plant and focal-bird sampling, assisted by high-resolution maps of the spatiotemporal distribution of Protea individuals and their flowering status. We found that Sugarbird's visitation preference increased with species' relative floral abundance, and that individual Sugarbirds tended to visit single species in sequence. Flower constancy during foraging bouts was significantly higher than expected from random plant-animal encounters at the scale of pollinator movements. Positive frequency dependence may favor the reproduction of abundant plant species while flower constancy may be particularly important for rare plant species. This first simultaneous study of both behaviors in a natural plant-pollinator system shows that bird pollinators exhibit both types of behavior and, in this way, possibly influence plant community structure.


Asunto(s)
Passeriformes/fisiología , Plantas/clasificación , Polinización/fisiología , Animales , Biodiversidad , Conducta Alimentaria , Flores , Especificidad de la Especie , Canales Aniónicos Dependientes del Voltaje
10.
Open Biol ; 6(8)2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27558933

RESUMEN

The glycoprotein sclerostin has been identified as a negative regulator of bone growth. It exerts its function by interacting with the Wnt co-receptor LRP5/6, blocks the binding of Wnt factors and thereby inhibits Wnt signalling. Neutralizing anti-sclerostin antibodies are able to restore Wnt activity and enhance bone growth thereby presenting a new osteoanabolic therapy approach for diseases such as osteoporosis. We have generated various Fab antibodies against human and murine sclerostin using a phage display set-up. Biochemical analyses have identified one Fab developed against murine sclerostin, AbD09097 that efficiently neutralizes sclerostin's Wnt inhibitory activity. In vitro interaction analysis using sclerostin variants revealed that this neutralizing Fab binds to sclerostin's flexible second loop, which has been shown to harbour the LRP5/6 binding motif. Affinity maturation was then applied to AbD09097, providing a set of improved neutralizing Fab antibodies which particularly bind human sclerostin with enhanced affinity. Determining the crystal structure of AbD09097 provides first insights into how this antibody might recognize and neutralize sclerostin. Together with the structure-function relationship derived from affinity maturation these new data will foster the rational design of new and highly efficient anti-sclerostin antibodies for the therapy of bone loss diseases such as osteoporosis.


Asunto(s)
Anticuerpos Neutralizantes/farmacología , Epítopos/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/química , Proteínas/antagonistas & inhibidores , Animales , Anticuerpos Neutralizantes/química , Sitios de Unión , Cristalografía por Rayos X , Variación Genética , Humanos , Fragmentos Fab de Inmunoglobulinas/química , Fragmentos Fab de Inmunoglobulinas/farmacología , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/metabolismo , Ratones , Modelos Moleculares , Biblioteca de Péptidos , Unión Proteica , Proteínas/genética , Proteínas/metabolismo , Relación Estructura-Actividad , Vía de Señalización Wnt
11.
Transpl Infect Dis ; 18(5): 721-729, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27502733

RESUMEN

BACKGROUND: Chronic diarrhea after kidney transplantation is often attributed to mycophenolic acid (MPA) toxicity. We hypothesize that intestinal infections contribute to the pathogenesis of chronic MPA-associated diarrhea. METHODS: In this retrospective study, all patients (n = 726) receiving a kidney transplant between 2000 and 2010 at the University Hospital Zurich were followed until July 2014 for occurrence of chronic diarrhea (≥4 weeks). Infectious triggers at diarrhea onset were assessed by reviewing medical history, stool microbiology, and histology of colon biopsies. RESULTS: In 46 patients (6.3% of the cohort), a total of 51 episodes of chronic diarrhea during MPA treatment were documented. The diarrhea episodes were often severe, as confirmed by significant weight loss. The cumulative incidence of chronic diarrhea was uniformly distributed throughout the post-transplant period, with 2.0%, 5.1%, and 9.6% at 1, 5, and 10 years, respectively. Evidence was found for intestinal infection at diarrhea onset in 38 episodes (74.5%). Occurrence of diarrhea onset showed a seasonal distribution with peaks in April and October/November. Specific antimicrobial treatment alone was associated with a 19% resolution rate only, whereas combination with dose reduction of MPA or switch from mycophenolate mofetil to enteric-coated mycophenolate sodium resulted in a 22.7% and 76.5% resolution rate, respectively. Change to an MPA-free regimen was associated with a 100% resolution rate. CONCLUSION: These results provide first evidence for a contribution of intestinal infections in chronic post-transplant diarrhea associated with MPA treatment.


Asunto(s)
Colitis/fisiopatología , Colon/microbiología , Diarrea/etiología , Diarrea/fisiopatología , Inmunosupresores/efectos adversos , Trasplante de Riñón/efectos adversos , Ácido Micofenólico/efectos adversos , Adulto , Área Bajo la Curva , Enfermedad Crónica , Colitis/epidemiología , Colitis/etiología , Colon/patología , Diarrea/epidemiología , Heces/microbiología , Femenino , Estudios de Seguimiento , Humanos , Inmunosupresores/administración & dosificación , Incidencia , Masculino , Persona de Mediana Edad , Ácido Micofenólico/administración & dosificación , Ácido Micofenólico/uso terapéutico , Estudios Retrospectivos , Suiza/epidemiología , Receptores de Trasplantes , Trasplante Homólogo/efectos adversos , Pérdida de Peso
12.
Plant Biol (Stuttg) ; 18(5): 750-60, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27270880

RESUMEN

The two-pore cation channel TPC1 operates as a dimeric channel in animal and plant endomembranes. Each subunit consists of two homologous Shaker-like halves, with 12 transmembrane domains in total (S1-S6, S7-S12). In plants, TPC1 channels reside in the vacuolar membrane, and upon voltage stimulation, give rise to the well-known slow-activating SV currents. Here, we combined bioinformatics, structure modelling, site-directed mutagenesis, and in planta patch clamp studies to elucidate the molecular mechanisms of voltage-dependent channel gating in TPC1 in its native plant background. Structure-function analysis of the Arabidopsis TPC1 channel in planta confirmed that helix S10 operates as the major voltage-sensing site, with Glu450 and Glu478 identified as possible ion-pair partners for voltage-sensing Arg537. The contribution of helix S4 to voltage sensing was found to be negligible. Several conserved negative residues on the luminal site contribute to calcium binding, stabilizing the closed channel. During evolution of plant TPC1s from two separate Shaker-like domains, the voltage-sensing function in the N-terminal Shaker-unit (S1-S4) vanished.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Canales de Calcio/metabolismo , Cationes/metabolismo , Modelos Estructurales , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Evolución Biológica , Calcio/metabolismo , Canales de Calcio/química , Canales de Calcio/genética , Membranas Intracelulares/metabolismo , Activación del Canal Iónico , Transporte Iónico , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Mutación , Técnicas de Placa-Clamp , Filogenia , Dominios Proteicos , Vacuolas/metabolismo
13.
Ecology ; 97(3): 576-82, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27197385

RESUMEN

An animal's trajectory is a fundamental object of interest in movement ecology, as it directly informs a range of topics from resource selection to energy expenditure and behavioral states. Optimally inferring the mostly unobserved movement path and its dynamics from a limited sample of telemetry observations is a key unsolved problem, however. The field of geostatistics has focused significant attention on a mathematically analogous problem that has a statistically optimal solution coined after its inventor, Krige. Kriging revolutionized geostatistics and is now the gold standard for interpolating between a limited number of autocorrelated spatial point observations. Here we translate Kriging for use with animal movement data. Our Kriging formalism encompasses previous methods to estimate animal's trajectories--the Brownian bridge and continuous-time correlated random walk library--as special cases, informs users as to when these previous methods are appropriate, and provides a more general method when they are not. We demonstrate the capabilities of Kriging on a case study with Mongolian gazelles where, compared to the Brownian bridge, Kriging with a more optimal model was 10% more precise in interpolating locations and 500% more precise in estimating occurrence areas.


Asunto(s)
Antílopes/fisiología , Modelos Biológicos , Actividad Motora/fisiología , Animales , Telemetría
14.
Micron ; 84: 79-95, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-27011256

RESUMEN

Confocal microscopy is widely used to measure the surface topography of specimen with a precision in the micrometer range. The measurement uncertainty and quality of the acquired data of confocal microscopy depends on various effects, such as optical aberrations, vibrations of the measurement setup and variations in the surface reflectivity. In this article, the influence of steep edges and undercuts on measurement results is examined. Steep edges on the specimen's surface lead to a reduced detector signal which influences the measurement accuracy and undercuts cause surface regions, which cannot be captured in a measurement. The article describes a method to overcome the negative effects of steep edges and undercuts by capturing several measurements of the surface with different angles between the surface and the optical axis of the objective. An algorithm is introduced which stitches different angle measurements together without knowledge of the exact position and orientation of the rotation axis. Thus, the measurement uncertainty due to steep edges and undercuts can be avoided without expensive high-precision rotation stages and time consuming adjustment of the measurement setup.


Asunto(s)
Microscopía Confocal/métodos , Algoritmos , Propiedades de Superficie
16.
Klin Padiatr ; 228(1): 24-8, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26356318

RESUMEN

UNLABELLED: In acute gastroenteritis (AG) fecal losses may cause depletion of sodium (NaD) which may not be recognized because of normal plasma Na (pNa) concentrations. We studied the incidence of this state of normonatremic sodium depletion (NNaD) and the suitability of the urinary Na/urinary creatinine ratio (uNa/uCr) for diagnosing NNaD. PATIENTS: 16 AG- and 16 healthy control children aged 0.8-15.0 years. METHODS: Prospective cross sectional pilot study. Measurements of Na, K and creatinine in plasma (p) and urine (u). Calculation of uNa/uCr Ratio, fractional excretion of Na (FENa) and uNa/uK ratio as the hitherto best known parameters of prerenal Na depletion, respectively. RESULTS: pNa concentrations were normal in 15/16 AG patients (93.8%) with only one subnormal value of 133 mmol/L, and a mean value of 137.9±2.3 mmol/L not different from the normal control group (139.4±2.2 mmol/L). Also, mean uNa concentrations and uNa/uK ratios did not differ between both groups. However, uNa/uCr ratios were below normal in 13/16 AG children (81.3%) but normal in all healthy controls with a significantly lower mean value in the AG group (12.6±8.8 vs. 31.2±8.3 mmol/mmol; p<0.0001). Similarly, 14/16 AG patients (87.5%) had a decreased FENa<0.5% with a mean FENa value significantly lower than in controls (0.36±0.28% vs. 0.95±0.26%, p<0.0001). The good agreement between FENa and uNa/uCr results was also reflected by a high correlation coefficient of r=0.9333. CONCLUSIONS: The majority of AG patients was found to have NNaD as determined by uNa/uCr and FENa. Calculation of uNa/uCr may be useful for diagnosing NNaD in AG.


Asunto(s)
Creatinina/orina , Gastroenteritis/complicaciones , Hiponatremia/diagnóstico , Hiponatremia/etiología , Sodio/orina , Enfermedad Aguda , Adolescente , Niño , Preescolar , Estudios Transversales , Femenino , Gastroenteritis/orina , Humanos , Hiponatremia/orina , Lactante , Masculino , Proyectos Piloto , Potasio/orina , Estudios Prospectivos
17.
Mol Plant ; 9(3): 428-436, 2016 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-26455461

RESUMEN

The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na(+)- and K(+)-permeable mutants function as ion channels rather than K(+) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na(+)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.


Asunto(s)
Proteínas de Transporte de Catión/metabolismo , Droseraceae/metabolismo , Fenómenos Electrofisiológicos , Proteínas de Plantas/metabolismo , Sodio/metabolismo , Animales , Transporte Biológico , Proteínas de Transporte de Catión/genética , Droseraceae/genética , Droseraceae/fisiología , Mutación , Proteínas de Plantas/genética , Conducta Predatoria
18.
Am J Transplant ; 16(2): 650-60, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26460801

RESUMEN

Human (Homo sapiens) micro-RNAs (hsa-miRNAs) regulate virus and host-gene translation, but the biological impact in patients with human cytomegalovirus (hCMV) infection is not well defined in a clinically relevant model. First, we compared hsa-miRNA expression profiles in peripheral blood mononuclear cells from 35 transplant recipients with and without CMV viremia by using a microarray chip covering 847 hsa-miRNAs. This approach demonstrated a set of 142 differentially expressed hsa-miRNAs. Next, we examined the effect of each of these miRNAs on viral growth by using human fibroblasts (human foreskin fibroblast-1) infected with the hCMV Towne strain, identifying a subset of proviral and antiviral hsa-miRNAs. miRNA-target prediction software indicated potential binding sites within the hCMV genome (e.g., hCMV-UL52 and -UL100 [UL = unique long]) and host-genes (e.g., interleukin-1 receptor, IRF1). Luciferase-expressing plasmid constructs and immunoblotting confirmed several predicted miRNA targets. Finally, we determined the expression of selected proviral and antiviral hsa-miRNAs in 242 transplant recipients with hCMV-viremia. We measured hsa-miRNAs before and after antiviral therapy and correlated hsa-miRNA expression levels to hCMV-replication dynamics. One of six antiviral hsa-miRNAs showed a significant increase during treatment, concurrent with viral decline. In contrast, six of eight proviral hsa-miRNAs showed a decrease during viral decline. Our results indicate that a complex and multitargeted hsa-miRNA response occurs during CMV replication in immunosuppressed patients. This study provides mechanistic insight and potential novel biomarkers for CMV replication.


Asunto(s)
Antivirales/uso terapéutico , Infecciones por Citomegalovirus/etiología , Rechazo de Injerto/etiología , MicroARNs/genética , Trasplante de Órganos/efectos adversos , Viremia/etiología , Replicación Viral/genética , Western Blotting , Estudios de Casos y Controles , Células Cultivadas , Estudios de Cohortes , Citomegalovirus/patogenicidad , Infecciones por Citomegalovirus/diagnóstico , Infecciones por Citomegalovirus/tratamiento farmacológico , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Estudios de Seguimiento , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/tratamiento farmacológico , Supervivencia de Injerto , Interacciones Huésped-Patógeno , Humanos , Complicaciones Posoperatorias , Pronóstico , ARN Mensajero/genética , ARN Viral/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Riesgo , Viremia/diagnóstico , Viremia/tratamiento farmacológico , Replicación Viral/efectos de los fármacos
19.
Am J Transplant ; 16(6): 1882-91, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-26713403

RESUMEN

We conducted an open-label, prospective, randomized trial to assess the efficacy and safety of RANKL inhibition with denosumab to prevent the loss of bone mineral density (BMD) in the first year after kidney transplantation. Ninety kidney transplant recipients were randomized 1:1 2 weeks after surgery to receive denosumab (60 mg at baseline and 6 months) or no treatment. After 12 months, total lumbar spine areal BMD (aBMD) increased by 4.6% (95% confidence interval [CI] 3.3-5.9%) in 46 patients in the denosumab group and decreased by -0.5% (95% CI -1.8% to 0.9%) in 44 patients in the control group (between-group difference 5.1% [95% CI 3.1-7.0%], p < 0.0001). Denosumab also increased aBMD at the total hip by 1.9% (95% CI, 0.1-3.7%; p = 0.035) over that in the control group at 12 months. High-resolution peripheral quantitative computed tomography in a subgroup of 24 patients showed that denosumab increased volumetric BMD at the distal tibia and radius (all p < 0.05). Biomarkers of bone turnover (C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide) markedly decreased with denosumab (all p < 0.0001). Episodes of cystitis and asymptomatic hypocalcemia occurred more often with denosumab, whereas graft function, rate of rejections, and incidence of opportunistic infections were similar. In conclusion, denosumab increased BMD in the first year after kidney transplantation but was associated with more frequent episodes of urinary tract infection.


Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Densidad Ósea/efectos de los fármacos , Remodelación Ósea/efectos de los fármacos , Huesos/efectos de los fármacos , Denosumab/uso terapéutico , Trasplante de Riñón/efectos adversos , Osteoporosis/prevención & control , Femenino , Humanos , Masculino , Persona de Mediana Edad , Osteoporosis/etiología , Estudios Prospectivos
20.
Cryobiology ; 71(3): 384-90, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26499840

RESUMEN

Cryopreservation is a technique that has been extensively used for storage of multipotent mesenchymal stromal cells (MSCs) in regenerative medicine. Therefore, improving current cryopreservation procedures in terms of increasing cell viability and functionality is important. In this study, we optimized the cryopreservation protocol of MSCs derived from the common marmoset Callithrix jacchus (cj), which can be used as a non-human primate model in various pathological and transplantation studies and have a great potential for regenerative medicine. We have investigated the effect of the active control of the nucleation temperature using induced nucleation at a broad range of temperatures and two different dimethylsulfoxide concentrations (Me2SO, 5% (v/v) and 10%, (v/v)) to evaluate the overall effect on the viability, metabolic activity and recovery of cells after thawing. Survival rate and metabolic activity displayed an optimum when ice formation was induced at -10 °C. Cryomicroscopy studies indicated differences in ice crystal morphologies as well as differences in intracellular ice formation with different nucleation temperatures. High subzero nucleation temperatures resulted in larger extracellular ice crystals and cellular dehydration, whereas low subzero nucleation temperatures resulted in smaller ice crystals and intracellular ice formation.


Asunto(s)
Criopreservación/métodos , Crioprotectores/farmacología , Células Madre Mesenquimatosas/citología , Animales , Supervivencia Celular/efectos de los fármacos , Dimetilsulfóxido/farmacología , Congelación , Células Madre Mesenquimatosas/efectos de los fármacos , Temperatura
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