Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
1.
J Microsc ; 263(2): 192-9, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27075881

RESUMEN

Aeroterrestrial green algae are exposed to desiccation in their natural habitat, but their actual volume changes have not been investigated. Here, we measure the relative volume reduction (RVRED ) in Klebsormidium crenulatum and Zygnema sp. under different preset relative air humidities (RH). A new chamber allows monitoring RH during light microscopic observation of the desiccation process. The RHs were set in the range of ∼4 % to ∼95% in 10 steps. RVRED caused by the desiccation process was determined after full acclimation to the respective RHs. In K. crenulatum, RVRED (mean ± SE) was 46.4 ± 1.9%, in Zygnema sp. RVRED was only 34.3 ± 2.4% at the highest RH (∼95%) tested. This indicates a more pronounced water loss at higher RHs in K. crenulatum versus Zygnema sp. By contrast, at the lowest RH (∼4%) tested, RVRED ranged from 75.9 ± 2.7% in K. crenulatum to 83.9 ± 2.2% in Zygnema sp. The final volume reduction is therefore more drastic in Zygnema sp. These data contribute to our understanding of the desiccation process in streptophytic green algae, which are considered the closest ancestors of land plants.


Asunto(s)
Chlorophyta/metabolismo , Desecación , Microscopía/métodos , Streptophyta/metabolismo , Chlorophyta/citología , Humedad , Streptophyta/citología , Agua/análisis
2.
Soft Matter ; 11(25): 5053-9, 2015 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-26027952

RESUMEN

Cells require adhesion to survive, proliferate and migrate, as well as for wound healing and many other functions. The strength of contractile cell forces on an underlying surface is a highly relevant quantity to measure the affinity of cells to a rigid surface with and without coating. Here we show with experimental and theoretical studies that these forces create surface stresses that are sufficient to induce measurable bending of macroscopic cantilevers. Since contractile forces are linked to the formation of focal contacts, results give information on adhesion promoting qualities and allow a comparison of very diverse materials. In exemplary studies, in vitro fibroblast adhesion on the magnetic shape memory alloy Fe-Pd and on the l-lysine derived plasma-functionalized polymer PPLL was determined. We show that cells on Fe-Pd are able to induce surface stresses three times as high as on pure titanium cantilevers. A further increase was observed for PPLL, where the contractile forces are four times higher than on the titanium reference. In addition, we performed finite element simulations on the beam bending to back up the calculation of contractile forces from cantilever bending under non-homogenous surface stress. Our findings consolidate the role of contractile forces as a meaningful measure of biomaterial performance.


Asunto(s)
Aleaciones/química , Materiales Biocompatibles/química , Fibroblastos/citología , Hierro/química , Ensayo de Materiales/instrumentación , Paladio/química , Polilisina/química , Animales , Adhesión Celular , Técnicas de Cultivo de Célula/instrumentación , Diseño de Equipo , Análisis de Elementos Finitos , Fenómenos Mecánicos , Ratones , Células 3T3 NIH , Gases em Plasma/química , Polímeros/química , Estrés Mecánico , Propiedades de Superficie
3.
Nanotechnology ; 26(12): 125704, 2015 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-25736739

RESUMEN

Surface stresses lead to an effective change in the elastic constants of thin films and at surfaces. The development of modern scanning probe techniques like contact resonance atomic force microscopy empowers the experimenter to measure at scales where these effects become increasingly relevant. In this paper we employ a computational multiscale approach where we compare density functional theory (DFT) and molecular dynamics simulations as tools to calculate the thin-film/surface elastic behavior for silicon and strontiumtitanate. From the surface elastic constants gained by DFT calculations we develop a continuum finite-element multilayer model to study the impact of surface stresses on indentation experiments. In general the stress field of an indenter and thus the impact of surface stresses on the indentation modulus depends on its contact radius and on its particular shape. We propose an analytical model that describes the behavior of the indentation modulus as a function of the contact radius. We show that this model fits well to simulation results gained for a spherical and a flat punch indenter. Our results demonstrate a surface-stress-induced reduction of the indentation modulus of about 5% for strontiumtitanate and 6% for silicon for a contact radius of [Formula: see text], irrespective of the indenter shape.

4.
Trees (Berl West) ; 27(3): 707-715, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23794789

RESUMEN

Lammas shoots are flushes formed by some woody species later in the growing season. Having less time to develop, tissue formation is suggested to be incomplete leading to a higher peridermal water loss during consecutive months. In this study, we analysed morphological and anatomical parameters, peridermal conductance to water vapour and the level of native embolism in mid-winter and late-winter of lammas shoots and normal spring shoots of the apple varieties Malus domestica 'Gala' and 'Nicoter'. Lammas shoots showed a significantly higher shoot cross-sectional area due to larger pith and corticular parenchyma areas. In contrast, phloem was significantly thicker in spring shoots. No pronounced differences were observed in xylem and collenchyma thickness or mean hydraulic conduit diameter. The phellem of spring shoots was composed of more suberinised cells compared to lammas shoots, which led to a significantly higher peridermal conductance in the latter. The amount of native embolism in mid-winter did not differ between shoot types, but in late-winter lammas shoots were more embolised than spring shoots. Data show that the restricted vegetation period of lammas shoots affects their development and, in consequence, their transpiration shield. This may also pose a risk for winter desiccation.

5.
J Laryngol Otol ; 137(5): 524-531, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-35791849

RESUMEN

OBJECTIVE: This study aimed to determine the predictors of olfactory improvement after endoscopic sinus surgery among patients with chronic rhinosinusitis with nasal polyps. METHOD: This prospective cohort study included patients admitted to a university hospital between 2006 and 2012. Assessment using odour identification testing, a sinonasal symptom questionnaire, the Rhinosinusitis Disability Index and mucus biomarker levels was performed at various time points. Correlation of variables with identification score differences at six post-operative time points and at baseline was performed, followed by multiple linear regression to determine significant predictors at each of the six post-operative time points. RESULTS: Baseline absence of acute sinusitis, elevated serpin F2 and anterior rhinorrhoea predict early olfactory improvement, whereas baseline allergic rhinitis predicts late olfactory improvement. Baseline odour identification score was the strongest predictor across all time points. CONCLUSION: Patients with chronic rhinosinusitis and nasal polyps with worse disease or baseline olfactory function may benefit more from endoscopic sinus surgery in terms of olfactory improvement.


Asunto(s)
Pólipos Nasales , Rinitis , Sinusitis , Humanos , Pólipos Nasales/complicaciones , Pólipos Nasales/cirugía , Estudios Prospectivos , Rinitis/complicaciones , Rinitis/cirugía , Sinusitis/complicaciones , Sinusitis/cirugía , Endoscopía , Olfato , Enfermedad Crónica
6.
Phys Rev Lett ; 109(19): 195704, 2012 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-23215403

RESUMEN

When processing Fe-Pd ferromagnetic shape memory thin films, selection of the desired phases and their transformation temperatures constitutes one of the largest challenges from an application point of view. In the present contribution we demonstrate that irradiation with 1.8 MeV Kr(+) ions is the method of choice to achieve this goal: Single crystalline Fe(7)Pd(3) thin films that are grown with molecular beam epitaxy on MgO (001) substrates and subsequently irradiated with ions reveal a phase transformation along the whole phase transformation path ranging from fcc austenite to bcc martensite. While for 10(14) ions/cm(2) a fcc-fct phase transformation is observed, increasing the fluence to 5 × 10(14) ions/cm(2) and 5 × 10(15) ions/cm(2) leads to a phase transformation to the bcc phase. Pole figure measurements reveal an orientation relationship for the fcc-bcc phase transformation according to Nishiyama and Wassermann.

7.
Vet Parasitol Reg Stud Reports ; 28: 100678, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35115118

RESUMEN

Bovine parafilariosis is an emerging fly-borne disease in central Europe, characterized by seasonal occurrence of hemorrhagic exudations ('bleeding spots') from the end of winter to end of summer. In two cases from Germany reported here, one animal of a small herd in Bavaria and 20 animals on a farm in Baden-Württemberg presented bleeding spots from late March and late April 2020, respectively. Exudate samples from both cases were positive for larvated Parafilaria eggs. Examination of the skin and trimmed tissue after slaughter of the animal from Bavaria resulted in the collection of 11 nematodes (two males, eight females, one specimen in fragments). The animal's carcass presented typical yellow-greenish areas and bloody spots on the subcutaneous tissue of the flesh side of the skin. The nematodes were microscopically determined as Parafilaria bovicola. Basic morphometric measurements of two (one intact) male and six female nematodes are within the ranges of published data; length (male/female) 28.8/48.0-64.5 mm; width, 397.6 µm/430.7-527.6 µm; distance of cervical papillae to anterior end, 177.6/248.9-337.4; left spiculum/right spiculum (male), 365.3-379.4/149.5-180.3 µm; gubernaculum 45.0-48.1 µm; distance of vulva to anterior end (female), 37.3-66.0 mm. In order to gain information on P. bovicola in its vector, 91 cattle-visiting Musca autumnalis flies were collected from the affected animal in Bavaria (36 flies) and from co-pastured animals (55 flies) for PCR analysis and sequencing. A total of 14 flies were PCR-positive for filarial DNA, and sequencing of a fragment of the cox1 gene resulted in identification of P. bovicola (n = 10) and Thelazia gulosa (n = 5). This report presents further cases of bovine parafilariosis in Germany, provides morphometric data on male and female P. bovicola nematodes retrieved from cattle and identified DNA of P. bovicola and T.gulosa in M. autumnalis flies collected at a site of occurrence of bovine parafilariosis.


Asunto(s)
Enfermedades de los Bovinos , Filarioidea , Muscidae , Animales , Bovinos , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/epidemiología , Europa (Continente) , Femenino , Alemania/epidemiología , Masculino
8.
Plant Biol (Stuttg) ; 24(7): 1240-1253, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35611757

RESUMEN

Climate change is expected to increase the frequency and intensity of summer droughts. Sufficient drought resistance, the ability to acclimate to and/or recover after drought, is thus crucial for forest tree species. However, studies on the hydraulics of mature trees during and after drought in natura are scarce. In this study, we analysed trunk water content (electrical resistivity: ER) and further hydraulic (water potential, sap flow density, specific hydraulic conductivity, vulnerability to embolism) as well as wood anatomical traits (tree ring width, conduit diameter, conduit wall reinforcement) of drought-stressed (artificially induced summer drought via throughfall-exclusion) and unstressed Picea abies and Fagus sylvatica trees. In P. abies, ER indicated a strong reduction in trunk water content after 5 years of summer drought, corresponding to significantly lower pre-dawn leaf water potential and xylem sap flow density. Vulnerability to embolism tended to be higher in drought-stressed trees. In F. sylvatica, only small differences between drought-stressed and control trees were observed. Re-watering led to a rapid increase in water potentials and xylem sap flow of both drought-stressed trees, and to increased growth rates in the next growing season. ER analyses revealed lower trunk water content in P. abies trees growing on throughfall-exclusion plots even 1 year after re-watering, indicating a limited capacity to restore internal water reserves. Results demonstrated that P. abies is more susceptible to recurrent summer drought than F. sylvatica, and can exhibit long-lasting and pronounced legacy effects in trunk water reserves.


Asunto(s)
Abies , Fagus , Picea , Pinus , Sequías , Estaciones del Año , Árboles , Agua
9.
J Interv Card Electrophysiol ; 65(2): 491-497, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35748975

RESUMEN

BACKGROUND: High-power short-duration (HPSD) radiofrequency ablation (RFA) is highly efficient and safe while reducing procedure and RF time in pulmonary vein isolation (PVI). The QDot™ catheter is a novel contact force ablation catheter that allows automated flow and power adjustments depending on the local tissue temperature to maintain a target temperature during 90 W/4 s lesions. We analysed intraprocedural data and periprocedural safety using the QDot-catheter in patients undergoing PVI for paroxysmal atrial fibrillation (PAF). METHODS: We included n = 48 patients undergoing PVI with the QDot-catheter with a temperature-controlled HPSD ablation mode with 90 W/4 s (TC-HPSD). If focal reconnection occurred besides repeat ablation, the ablation mode was changed to 50 W/15 s (QMode). N = 23 patients underwent cerebral MRI to detect silent cerebral lesions. RESULTS: Mean RF time was 8.1 ± 2.8 min, and procedure duration was 84.5 ± 30 min. The overall maximal measured catheter tip temperature was 52.0 °C ± 4.6 °C, mean overall applied current was 871 mA ± 44 mA and overall applied energy was 316 J ± 47 J. The mean local impedance drop was 12.1 ± 2.4 Ohms. During adenosine challenge, n = 14 (29%) patients showed dormant conduction. A total of n = 24 steam pops were detected in n = 18 patients (39.1%), while no pericardial tamponade occurred. No periprocedural thromboembolic complications occurred, while n = 4 patients (17.4%) showed silent cerebral lesion. CONCLUSIONS: TC-HPSD ablation with 90 W/4 s using the QDot-catheter led to a reduction of procedure and RF time, while no major complications occurred. Despite optimized temperature control and power adjustment, steam pops occurred in a rather high number of patients, while none of them leads to tamponade or to clinical or neurological deficits.


Asunto(s)
Fibrilación Atrial , Ablación por Catéter , Venas Pulmonares , Humanos , Venas Pulmonares/diagnóstico por imagen , Venas Pulmonares/cirugía , Temperatura , Vapor , Diseño de Equipo , Ablación por Catéter/métodos , Fibrilación Atrial/diagnóstico por imagen , Fibrilación Atrial/cirugía , Fibrilación Atrial/etiología , Imagen por Resonancia Magnética , Resultado del Tratamiento
10.
J Exp Bot ; 61(12): 3385-93, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20551085

RESUMEN

The Cavitron technique facilitates time and material saving for vulnerability analysis. The use of rotors with small diameters leads to high water pressure gradients (DeltaP) across samples, which may cause pit aspiration in conifers. In this study, the effect of pit aspiration on Cavitron measurements was analysed and a modified 'conifer method' was tested which avoids critical (i.e. pit aspiration inducing) DeltaP. Four conifer species were used (Juniperus communis, Picea abies, Pinus sylvestris, and Larix decidua) for vulnerability analysis based on the standard Cavitron technique and the conifer method. In addition, DeltaP thresholds for pit aspiration were determined and water extraction curves were constructed. Vulnerability curves obtained with the standard method showed generally a less negative P for the induction of embolism than curves of the conifer method. Differences were species-specific with the smallest effects in Juniperus. Larix showed the most pronounced shifts in P(50) (pressure at 50% loss of conductivity) between the standard (-1.5 MPa) and the conifer (-3.5 MPa) methods. Pit aspiration occurred at the lowest DeltaP in Larix and at the highest in Juniperus. Accordingly, at a spinning velocity inducing P(50), DeltaP caused only a 4% loss of conductivity induced by pit aspiration in Juniperus, but about 60% in Larix. Water extraction curves were similar to vulnerability curves indicating that spinning itself did not affect pits. Conifer pit aspiration can have major influences on Cavitron measurements and lead to an overestimation of vulnerability thresholds when a small rotor is used. Thus, the conifer method presented here enables correct vulnerability analysis by avoiding artificial conductivity losses.


Asunto(s)
Tracheophyta/fisiología , Agua/análisis , Centrifugación/métodos , Presión , Agua/fisiología
11.
Eur Arch Otorhinolaryngol ; 267(11): 1719-25, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20422201

RESUMEN

Altered nasality influences speech intelligibility. Automatic speech recognition (ASR) has proved suitable for quantifying speech intelligibility in patients with different degrees of nasal emissions. We investigated the influence of hyponasality on the results of speech recognition before and after nasal surgery using ASR. Speech recordings, nasal peak inspiratory flow and self-perception measurements were carried out in 20 German-speaking patients (8 women, 12 men; aged 38 ± 22 years) who underwent surgery for various nasal and sinus pathologies. The degree of speech intelligibility was quantified as the percentage of correctly recognized words of a standardized word chain by ASR (word recognition rate; WR). WR was measured 1 day before (t1), 1 day after with nasal packings (t2), and 3 months after (t3) surgery; nasal peak flow on t1 and t3. WR was calculated with program for the automatic evaluation of all kinds of speech disorders (PEAKS). WR as a parameter of speech intelligibility was significantly decreased immediately after surgery (t1 vs. t2 p < 0.01) but increased 3 months after surgery (t2 vs. t3 p < 0.01). WR showed no association with age or gender. There was no significant difference between WR at t1 and t3, despite a post-operative increase in nasal peak inspiratory flow measurements. The results show that ASR is capable of quantifying the influence of hyponasality on speech; nasal obstruction leads to significantly reduced WR and nasal peak flow cannot replace evaluation of nasality.


Asunto(s)
Obstrucción Nasal/fisiopatología , Enfermedades Nasales/cirugía , Enfermedades de los Senos Paranasales/cirugía , Inteligibilidad del Habla , Software de Reconocimiento del Habla , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Resistencia de las Vías Respiratorias , Endoscopía , Femenino , Humanos , Capacidad Inspiratoria , Masculino , Persona de Mediana Edad , Enfermedades Nasales/fisiopatología , Enfermedades de los Senos Paranasales/fisiopatología
12.
Thorax ; 64(6): 535-40, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19282318

RESUMEN

RATIONALE: Lower airway (LAW) infection with Pseudomonas aeruginosa and Staphylococcus aureus is the leading cause of morbidity in cystic fibrosis (CF). The upper airways (UAW) were shown to be a gateway for acquisition of opportunistic bacteria and to act as a reservoir for them. Therefore, tools for UAW assessment within CF routine care require evaluation. OBJECTIVES: The aims of the study were non-invasive assessment of UAW and LAW microbial colonisation, and genotyping of P aeruginosa and S aureus strains from both segments. METHODS: 182 patients with CF were evaluated (age 0.4-68 years, median 17 years). LAW specimens were preferably sampled as expectorated sputum and UAW specimens by nasal lavage. P aeruginosa and S aureus isolates were typed by informative single nucleotide polymorphisms (SNPs) or by spa typing, respectively. RESULTS: Of the typable S aureus and P aeruginosa isolates from concomitant UAW- and LAW-positive specimens, 31 of 36 patients were carrying identical S aureus spa types and 23 of 24 patients identical P aeruginosa SNP genotypes in both compartments. Detection of S aureus or P aeruginosa in LAW specimens was associated with a 15- or 88-fold higher likelihood also to identify S aureus or P aeruginosa in a UAW specimen from the same patient. CONCLUSIONS: The presence of identical genotypes in UAW and LAW suggests that the UAW play a role as a reservoir of S aureus and P aeruginosa in CF. Nasal lavage appears to be suitable for non-invasive UAW sampling, but further longitudinal analyses and comparison with invasive methods are required. While UAW bacterial colonisation is typically not assessed in regular CF care, the data challenge the need to discuss diagnostic and therapeutic standards for this airway compartment. TRIAL REGISTRATION NUMBER: NCT00266474.


Asunto(s)
Fibrosis Quística/complicaciones , Infecciones por Pseudomonas/complicaciones , Pseudomonas aeruginosa/genética , Infecciones Estafilocócicas/complicaciones , Staphylococcus aureus/genética , Adolescente , Adulto , Factores de Edad , Anciano , Técnicas de Tipificación Bacteriana/métodos , Niño , Preescolar , Femenino , Genotipo , Humanos , Lactante , Masculino , Persona de Mediana Edad , Cavidad Nasal/microbiología , Infecciones Oportunistas/complicaciones , Infecciones Oportunistas/microbiología , Polimorfismo de Nucleótido Simple , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/aislamiento & purificación , Manejo de Especímenes/métodos , Esputo/microbiología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Irrigación Terapéutica
13.
Science ; 255(5052): 1683-5, 1992 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-1553555

RESUMEN

Experimental studies show that optical irradiation far from any absorption bands can shift the resonances in a nuclear magnetic resonance (NMR) spectrum without significant heating. This effect may lead to increased dispersion in NMR studies of complex molecules.


Asunto(s)
Espectroscopía de Resonancia Magnética/instrumentación , Alcanfor/química , Rayos Láser
14.
Plant Pathol ; 67(5): 1122-1130, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29861507

RESUMEN

High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri, a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n = 62) and by the use of a semiprofessional quadcopter (n = 13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background (R2 = 0.87) and with black background (R2 = 0.95), juvenile plants (R2 = 0.94), and top views and side views of entire tree crowns of adult trees (R2 = 0.98 and 0.88, respectively). Results underline that a well-defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time-efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.

15.
Dtsch Tierarztl Wochenschr ; 114(6): 231-5, 2007 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-17642324

RESUMEN

The objective of this study was to test for correlations between alopecia and ruminal drinking in young calves. 331 calves up to an age of 31 days were tested for evidence of generalized hair loss daily during their stay in the clinic. Incidence of diarrhoea and the results of ruminal fluid and blood analysis were compared between the groups with and without alopecia. Calves with alopecia showed a significantly higher incidence of diarrhoea and of ruminal acidosis persisting for at least 24 hours. Blood analysis revealed significant differences in degree of acidosis, in concentrations of D-lactate, urea, and creatinine in serum as well as in the activities of glutathione peroxidase, aspartate amino transferase, and creatine kinase. Alopecia in calves is correlated to longer periods of diseases, which are known to be accompanied by the production of D-lactate in the gastrointestinal tract, such as diarrhoea and ruminal drinking. The question, whether alopecia is due to formation of toxic substances or to deficiency of essential substances can not be answered.


Asunto(s)
Alopecia/veterinaria , Enfermedades de los Bovinos/etiología , Contenido Digestivo/química , Rumen/química , Gastropatías/veterinaria , Alopecia/etiología , Alopecia/fisiopatología , Animales , Bovinos , Enfermedades de los Bovinos/fisiopatología , Diarrea/fisiopatología , Diarrea/veterinaria , Femenino , Concentración de Iones de Hidrógeno , Masculino , Rumen/metabolismo , Gastropatías/complicaciones , Gastropatías/fisiopatología
16.
J Appl Physiol (1985) ; 101(2): 448-53, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16614359

RESUMEN

Several studies indicate that cell-mediated immune responses, i.e., macrophage (MPhi) cytokine release capacities, myosin heavy chain (MHC) class II (Ia) expression, etc., are suppressed after trauma-hemorrhage in male mice. Testosterone has been shown to be responsible for the depression of MPhi cytokine responses in males after trauma-hemorrhage. Antigen presentation via MHC class II plays a key role in initiating and maintaining cell-mediated and humoral immune responses. It remains unknown, however, whether testosterone has any effect on MHC class II after trauma-hemorrhage. To study this, male C3H/HeN mice were castrated or sham castrated 2 wk before trauma (midline laparotomy) and hemorrhage (Hem; blood pressure 35 +/- 5 mmHg for 90 min and resuscitation) or sham operation. Four hours thereafter, MHC class II (Ia) expression was measured using flow cytometry. The results indicate that MHC class II (Ia) expression on peritoneal and splenic MPhi was significantly suppressed in male mice after trauma-hemorrhage. Prior castration, however, prevented the depression in MHC class II (Ia) expression on peritoneal and splenic MPhi after trauma-hemorrhage. Castration did not affect MHC class II (Ia) expression in MPhi from sham-castrated mice. Thus testosterone depresses MHC class II (Ia) expression on peritoneal and splenic MPhi after trauma-hemorrhage in males. Because MHC class II is necessary for an adequate immune response, our results suggest that depletion of male sex steroids or blockade of androgen receptors using agents such as flutamide might prevent immunosuppression via maintaining MHC class II (Ia) expression after trauma and severe blood loss.


Asunto(s)
Hemorragia/inmunología , Antígenos de Histocompatibilidad Clase II/metabolismo , Macrófagos Peritoneales/inmunología , Orquiectomía , Heridas y Lesiones/inmunología , Antagonistas de Andrógenos/farmacología , Antagonistas de Receptores Androgénicos , Animales , Presentación de Antígeno , Antígeno CD11b/metabolismo , Flutamida/farmacología , Hemorragia/patología , Terapia de Inmunosupresión , Macrófagos Peritoneales/patología , Masculino , Ratones , Ratones Endogámicos C3H , Receptores Androgénicos/efectos de los fármacos , Testosterona/fisiología , Heridas y Lesiones/patología
17.
Nanoscale ; 8(17): 9398-404, 2016 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-27093061

RESUMEN

Nanocomposites constitute an upcoming class of materials that has enormous potential within a broad range of areas, particularly with regard to mechanical applications. However, the tuning of material properties requires a full understanding of the mechanical response of the nanocomposite across all length scales. While characterization from the micro to macroscale is well established at this point, quantification of mechanical behavior at the nanoscale is still an unresolved challenge. With this background, the current work demonstrates the capabilities of quantitative contact resonance atomic force microscopy (CR-AFM) to localize and reliably characterize Ni nanoparticles that are embedded below the surface of thermally oxidized silicon thin films. Correlating these results with numerical simulations as well as high-resolution transmission electron microscopy measurements provides a comprehensive understanding of the subtle interplay between the structure and nanomechanical response of the composite.

18.
J Appl Physiol (1985) ; 86(1): 101-4, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9887119

RESUMEN

Previous studies have demonstrated exercise-induced heat shock protein 70 (HSP70) in animals. The purpose of this study was to investigate human skeletal muscle HSP70 response to rowing training. Ten male rowers trained for 4 wk with different forms, durations, and intensities of exercise. Biopsy was performed in the right musculus vastus lateralis before training and at the end of each week. HSP70 in 5 microg of total protein from the muscle sample was determined by using Western blot and immunodetection with chemiluminescence technique, by means of laser densitometer referring to a series of known standard HSP70. Compared with pretraining (100%), HSP70 increased during training (181, 405, 456, and 363% from the first to fourth training week, respectively) with the maximum HSP70 production at the end of second training week. Thus HSP70 is induced in highly trained human muscle by long-term training.


Asunto(s)
Proteínas HSP70 de Choque Térmico/biosíntesis , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiología , Aptitud Física/fisiología , Adolescente , Western Blotting , Electroforesis en Gel de Poliacrilamida , Humanos , Mediciones Luminiscentes , Masculino , Esfuerzo Físico/fisiología
19.
Science ; 259(5096): 836, 1993 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-17809347
20.
Phytochemistry ; 57(8): 1281-5, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11454360

RESUMEN

A new cytotoxic 1,7-dioxa-dispiro[5.1.5.2]pentadeca-9,12-dien-11-one derivative, aculeatin D, and a new alkenone, 5-hydroxy-hexacos-1-en-3-one, have been isolated as minor compounds from the rhizomes of Amomum aculeatum. Their structures have been determined mainly by NMR spectroscopy and mass spectrometry. Aculeatin D showed high cytotoxicity against the KB and the L-6 cell line with IC(50) of 0.38 microg/ml and 1 microg/ml, respectively. Additionally, it revealed remarkable activity against two Plasmodium falciparum strains, as well as against Trypanosoma brucei rhodesiense and Trypanosoma cruzi. 5-Hydroxy-hexacos-1-en-3-one exhibited neither cytotoxic nor antiprotozoal activity, whereas antibacterial testing against Bacillus cereus, Escherichia coli and Staphylococcus epidermidis showed moderate to strong activity for both compounds.


Asunto(s)
Alquenos/aislamiento & purificación , Antiinfecciosos/aislamiento & purificación , Antineoplásicos Fitogénicos/aislamiento & purificación , Cetonas/aislamiento & purificación , Plantas Medicinales/química , Compuestos de Espiro/aislamiento & purificación , Alquenos/química , Alquenos/farmacología , Animales , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Antiprotozoarios/química , Antiprotozoarios/aislamiento & purificación , Antiprotozoarios/farmacología , Línea Celular , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Concentración 50 Inhibidora , Cetonas/química , Cetonas/farmacología , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Pruebas de Sensibilidad Microbiana , Nueva Guinea , Tallos de la Planta/química , Ratas , Compuestos de Espiro/química , Compuestos de Espiro/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA