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1.
BMC Genomics ; 23(1): 321, 2022 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-35459090

RESUMEN

BACKGROUND: Previous phylogeographic studies of the lion (Panthera leo) have improved our insight into the distribution of genetic variation, as well as a revised taxonomy which now recognizes a northern (Panthera leo leo) and a southern (Panthera leo melanochaita) subspecies. However, existing whole range phylogeographic studies on lions either consist of very limited numbers of samples, or are focused on mitochondrial DNA and/or a limited set of microsatellites. The geographic extent of genetic lineages and their phylogenetic relationships remain uncertain, clouded by massive sampling gaps, sex-biased dispersal and incomplete lineage sorting. RESULTS: In this study we present results of low depth whole genome sequencing and subsequent variant calling in ten lions sampled throughout the geographic range, resulting in the discovery of >150,000 Single Nucleotide Polymorphisms (SNPs). Phylogenetic analyses revealed the same basal split between northern and southern populations, as well as four population clusters on a more local scale. Further, we designed a SNP panel, including 125 autosomal and 14 mitochondrial SNPs, which was tested on >200 lions from across their range. Results allow us to assign individuals to one of these four major clades (West & Central Africa, India, East Africa, or Southern Africa) and delineate these clades in more detail. CONCLUSIONS: The results presented here, particularly the validated SNP panel, have important applications, not only for studying populations on a local geographic scale, but also for tracing samples of unknown origin for forensic purposes, and for guiding conservation management of ex situ populations. Thus, these genomic resources not only contribute to our understanding of the evolutionary history of the lion, but may also play a crucial role in conservation efforts aimed at protecting the species in its full diversity.


Asunto(s)
Leones , Panthera , Animales , Variación Genética , Humanos , Leones/genética , Panthera/genética , Filogenia , Polimorfismo de Nucleótido Simple , Secuenciación Completa del Genoma
2.
Anim Genet ; 52(5): 675-682, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34143521

RESUMEN

The domestic cat (Felis silvestris catus) is a valued companion animal throughout the world. Over 60 different cat breeds are accepted for competition by the cat fancy registries in different countries. Genetic markers, including short tandem repeats and SNPs, are available to evaluate and manage levels of inbreeding and genetic diversity, population and breed structure relationships, and individual identification for forensic and registration purposes. The International Society of Animal Genetics (ISAG) hosts the Applied Genetics in Companion Animals Workshop, which supports the standardization of genetic marker panels and genotyping for the identification of cats via comparison testing. SNP panels have been in development for many species, including the domestic cat. An ISAG approved core panel of SNPs for use in cat identification and parentage analyses is presented. SNPs (n = 121) were evaluated by different university-based and commercial laboratories using 20 DNA samples as part of the ISAG comparison testing procedures. Different SNP genotyping technologies were examined, including DNA arrays, genotyping-by-sequencing and mass spectroscopy, to select a robust and efficient panel of 101 SNPs as the ISAG core panel for cats. The SNPs are distributed across all chromosomes including two on the X chromosome and an XY pseudo-autosomal sexing marker (zinc-finger XY; ZFXY). A population study demonstrated that the markers have an average polymorphic information content of 0.354 and a power of exclusion greater than 0.9999. The SNP panel should keep testing affordable while also allowing for the development of additional panels to monitor health, phenotypic traits, hybrid cats and highly inbred cats.


Asunto(s)
Gatos/genética , Marcadores Genéticos , Técnicas de Genotipaje , Polimorfismo de Nucleótido Simple , Animales , Cruzamiento , Genética de Población , Técnicas de Genotipaje/normas , Análisis de Secuencia por Matrices de Oligonucleótidos/normas
3.
Internist (Berl) ; 61(7): 746-753, 2020 Jul.
Artículo en Alemán | MEDLINE | ID: mdl-32533196

RESUMEN

A 57-year-old woman underwent esophagogastroduodenoscopy due to a continuous drop in hemoglobin levels reaching 7.4 g/dl after treatment with intravenous thrombolytic therapy 1 week earlier because of an ischemic insult. Numerous erosive lesions were found in the gastric corpus. Histological staining of a specimen from the gastric lesions revealed a poorly differentiated adenocarcinoma. Immunohistochemical examination confirmed the diagnosis of gastric metastasis from lung cancer based on positive staining for thyroid transcriptional factor­1 (TTF-1) and cytokeratin 7 (CK7) as well as via negative staining for caudal-type homeobox­2 (CDX-2). Chest computed tomography demonstrated a mediastinal mass, measuring 3.2 cm and involving the cervical and supraclavicular lymph nodes. A lymph node was subsequently extirpated. Immunohistochemical examination confirmed the diagnosis of lymph node metastasis from lung cancer by positive staining for TTF­1 and CK7. Symptomatic gastric metastasis from lung cancer is an extremely rare clinical entity. Transesophageal echocardiography detected a mass measuring 1.6 cm at the mitral valve with pericardial effusion. On the basis of the echocardiographic findings, a malignant origin was suggested after exclusion of infectious endocarditis. We assumed that the multiple organ infarctions (spleen, kidney, and brain) and gastric hematogenous metastasis must have been caused by disseminated arterial tumor embolism from the intracardiac metastasis. The patient was treated palliatively and died.


Asunto(s)
Adenocarcinoma/patología , Gastritis/patología , Hemoglobinas/efectos de los fármacos , Accidente Cerebrovascular/terapia , Terapia Trombolítica/efectos adversos , Ecocardiografía Transesofágica , Resultado Fatal , Femenino , Humanos , Persona de Mediana Edad
4.
Eur Cell Mater ; 31: 296-311, 2016 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-27227787

RESUMEN

Tissue barriers function as "gate keepers" between different compartments (usually blood and tissue) and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF)-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB). By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies.


Asunto(s)
Vasos Sanguíneos/fisiología , Tendones/irrigación sanguínea , Adulto , Anciano , Animales , Biotina/metabolismo , Vasos Sanguíneos/ultraestructura , Western Blotting , Proliferación Celular , Células Cultivadas , Femenino , Humanos , Inmunohistoquímica , Masculino , Ratones Endogámicos C57BL , Persona de Mediana Edad , ARN/aislamiento & purificación , Coloración y Etiquetado , Tendones/citología , Tendones/ultraestructura , beta-Galactosidasa/metabolismo
5.
Phys Rev Lett ; 113(23): 237204, 2014 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-25526154

RESUMEN

Magnetic relaxation is one of the dominating features of magnetization dynamics. Depending on the magnetic structure and the experimental approach, different magnitudes of the damping parameter are reported even for a given material. In this study, we experimentally address this issue by accessing the damping parameter in the same magnetic nanotracks using different approaches: local ferromagnetic resonance (α=0.0072) and field-driven domain wall dynamics (α=0.023). The experimental results cannot fully be accounted for by modeling only roughness in micromagnetic simulations. Consequently, we have included nonlocal texture induced damping to the micromagnetic code. We find excellent agreement with the observed increased damping in the vortex structures for the same input Gilbert alpha when texture-induced nonlocal damping is included.

6.
Ecol Lett ; 16(11): 1414, e4, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23962143

RESUMEN

Creel et al. argue against the conservation effectiveness of fencing based on a population measure that ignores the importance of top predators to ecosystem processes. Their statistical analyses consider, first, only a subset of fenced reserves and, second, an incomplete examination of 'costs per lion.' Our original conclusions remain unaltered.


Asunto(s)
Carnívoros , Conservación de los Recursos Naturales/métodos , Leones , Densidad de Población , Animales , Humanos
7.
Ecol Lett ; 16(5): 635-41, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23461543

RESUMEN

Conservationists often advocate for landscape approaches to wildlife management while others argue for physical separation between protected species and human communities, but direct empirical comparisons of these alternatives are scarce. We relate African lion population densities and population trends to contrasting management practices across 42 sites in 11 countries. Lion populations in fenced reserves are significantly closer to their estimated carrying capacities than unfenced populations. Whereas fenced reserves can maintain lions at 80% of their potential densities on annual management budgets of $500 km(-2) , unfenced populations require budgets in excess of $2000 km(-2) to attain half their potential densities. Lions in fenced reserves are primarily limited by density dependence, but lions in unfenced reserves are highly sensitive to human population densities in surrounding communities, and unfenced populations are frequently subjected to density-independent factors. Nearly half the unfenced lion populations may decline to near extinction over the next 20-40 years.


Asunto(s)
Carnívoros , Conservación de los Recursos Naturales/métodos , Leones , Densidad de Población , Animales , Conservación de los Recursos Naturales/economía , Ghana , Humanos , Namibia , Dinámica Poblacional , Sector Privado , Sudáfrica
8.
Minerva Urol Nefrol ; 65(1): 9-20, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23538307

RESUMEN

Urinary tract infections (UTI) are among the most frequent bacterial infections in the community and health care setting. Mostly young and, to some extent, postmenopausal women are affected by recurrent UTI (rUTI) defined as ≥3 UTI/year or ≥2 UTI/half year. In contrast, rUTI is rare in healthy men. On the other hand, rUTI are frequently found in female and male patients with complicating urological factors, e.g. urinary catheters, infection stones. Remediable predisposing factors in uncomplicated rUTI in women are rare. In complicated rUTI the success depends mainly on the possibility to eliminate or at leastimprove the complicating risk factors. Continuous antibiotic prophylaxis or postcoital prophylaxis, if there is close correlation with sexual intercourse, are most effective to prevent rUTI. Nitrofurantoin, trimethoprim (or cotrimoxazole), and fosfomycin trometamol are available as first-line drugs. Oral cephalosporins and quinolones should be restricted to specific indications. Antibiotic prophylaxis reduces the number of uropathogens in the gut and/or vaginal flora and reduces bacterial "fitness". Given the correct indication, the recurrence rate of rUTI can be reduced by about 90%. Due to possible adverse events and the concern of selecting resistant pathogens, according to the guidelines of the European Association of Urology antimicrobial prophylaxis should be considered only after counselling, behavioural modification and non-antimicrobial measures have been attempted. In postmenopausal patients vaginal substitution of oestriol should be started first. Oral or parenteral immunoprophylaxis is another option in patients with rUTI. Other possibilities with varying scientific evidence are prophylaxis with cranberry products, specific plant combinations or probiotics. The prophylaxis of catheter-associated UTI should employ strategies which result in a reduction of frequency and duration of catheter drainage of the urinary tract. The currently available catheter materials have only little influence on reducing catheter-associated rUTI.


Asunto(s)
Infecciones Urinarias/prevención & control , Adyuvantes Inmunológicos/uso terapéutico , Antiinfecciosos/uso terapéutico , Profilaxis Antibiótica , Infecciones Relacionadas con Catéteres/etiología , Infecciones Relacionadas con Catéteres/prevención & control , Coito , Diuréticos/uso terapéutico , Terapia de Reemplazo de Estrógeno , Femenino , Humanos , Higiene , Intestinos/microbiología , Masculino , Fitoterapia , Probióticos/uso terapéutico , Factores de Riesgo , Prevención Secundaria , Cateterismo Urinario/efectos adversos , Infecciones Urinarias/epidemiología , Infecciones Urinarias/etiología , Vagina/microbiología
9.
Oper Dent ; 38(2): 159-67, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-22788727

RESUMEN

SUMMARY The following parameters were varied: 1) irradiation technique: top and bottom polymerization according to the ISO standard, and polymerization from only the top, simulating clinical situations; 2) polymerization time: 5, 10, 20, and 40 seconds; 3) storage conditions: 24 hours in distilled water, thermocycling followed by storage for four weeks in artificial saliva or alcohol. Flexural strength (FS), flexural modulus (Eflexural), indentation modulus (E), Vickers hardness (HV), and degree of conversion (DC) were measured. The laboratory results were similar to those measured by mimicking clinical conditions only at high polymerization times and mild storage conditions (20 seconds and 40 seconds and storage for 24 hours in water, and 40 seconds with aging and storing in saliva). Significantly higher DC values were measured on the top than on the bottom of a 2-mm layer for all polymerization times. Overall, 5-second and 10-second irradiation times induced significantly lower DC values compared to the currently recommended polymerization times of 20 and 40 seconds at both the top and bottom of the samples. The initial DC differences as a function of irradiation time are leveled at 24 hours of storage but seem to do well in predicting long-term material behavior. A minimum irradiation time of 20 seconds is necessary clinically to achieve the best mechanical properties with modern high-intensity light emitting diode (LED) units.


Asunto(s)
Resinas Compuestas/química , Materiales Dentales/química , Curación por Luz de Adhesivos Dentales , Compuestos de Bario/química , Compuestos Inorgánicos de Carbono/química , Luces de Curación Dental/clasificación , Análisis del Estrés Dental/instrumentación , Módulo de Elasticidad , Etanol/química , Dureza , Humanos , Curación por Luz de Adhesivos Dentales/instrumentación , Curación por Luz de Adhesivos Dentales/métodos , Ensayo de Materiales , Metacrilatos/química , Nanocompuestos/química , Docilidad , Polimerizacion , Saliva Artificial/química , Compuestos de Silicona/química , Dióxido de Silicio/química , Solventes/química , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de Tiempo , Agua/química , Circonio/química
10.
Zentralbl Chir ; 138(6): 622-9, 2013 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-22113589

RESUMEN

BACKGROUND: Insufficient nutrition in surgical patients increases perioperative morbidity, mortality, length of stay and therapy costs. Therefore, guidelines declare the integration of nutrition into the overall management as one of the key aspects of perioperative care. This study was conducted to evaluate the current clinical practice of clinical nutrition in surgical departments in Germany. METHODS: In 2009 German Surgical Society (DGCH) members in leading positions were surveyed with a standardised online questionnaire concerning their perioperative nutritional routines in elective surgery. RESULTS: From the addressed physicians n = 156 (6.24 %) answered. Of those, 86.9 % consider the nutritional status of their patients. Only 6 % use standardised nutritional screening tools. Short preoperative fasting for solid and liquid food is practiced by 65 % and 40 %, respectively. After the operation, 65 % allow intake of clear fluids on the day of surgery and 78 % initiate solid food on the day of surgery or the first postoperative day. Oral nutritional supplements are given only "sometimes" or "rarely" by 53.9 % of the respondents. CONCLUSION: The low response rate may imply the dilemma that the evidence-based benefit of perioperative nutrition does not meet sufficient interest. Even in case of a positive selection of "pro-nutrition respondents", standardised preoperative malnutrition screening is also rare. Aspects such as shorter perioperative fasting are already practiced more progressively. However, still greater efforts are needed to promote guideline-based clinical nutrition in surgical care in Germany.


Asunto(s)
Actitud del Personal de Salud , Internet , Encuestas Nutricionales , Terapia Nutricional , Atención Perioperativa , Procedimientos Quirúrgicos Operativos , Medicina Basada en la Evidencia , Alemania , Adhesión a Directriz , Humanos , Necesidades Nutricionales , Estado Nutricional , Servicio de Cirugía en Hospital , Encuestas y Cuestionarios
11.
Horm Metab Res ; 44(7): 506-10, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22689208

RESUMEN

Diabetes mellitus is a risk factor for various types of tendon disorders. The mechanisms underlying diabetes associated tendinopathies remain unclear, but typically, systemic factors related to high blood glucose levels are thought to be causally involved. We hypothesize that tendon immanent cells might be directly involved in diabetic tendinopathy. We therefore analyzed human and rat tendons by immunohistochemistry, laser capture microdissection, and single cell PCR for pancreatic ß-cell associated markers. Moreover, we examined the short term effects of a single injection of streptozotocin, a toxin for GLUT2 expressing cells, in rats on insulin expression of tendon cells, and on the biomechanical properties of Achilles tendons. Tendon cells, both in the perivascular area and in the dense collagenous tissue express insulin and Glut2 on both protein and mRNA levels. In addition, glucagon and PDX-1 are present in tendon cells. Intraperitoneal injection of streptozotocin caused a loss of insulin and insulin mRNA in rat Achilles tendons after only 5 days, accompanied by a 40% reduction of mechanical strength. In summary, a so far unrecognized, extrapancreatic, insulin-producing cell type, possibly playing a major role in the pathophysiology of diabetic tendinopathy is described. In view of these data, novel strategies in tendon repair may be considered. The potential of the described cells as a tool for treating diabetes needs to be addressed by further studies.


Asunto(s)
Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología , Insulina/biosíntesis , Tendones/patología , Tendón Calcáneo/metabolismo , Tendón Calcáneo/patología , Adulto , Anciano , Animales , Western Blotting , Diabetes Mellitus/patología , Femenino , Glucosa/farmacología , Humanos , Inmunohistoquímica , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/efectos de los fármacos , Masculino , Persona de Mediana Edad , Ratas , Adulto Joven
12.
Unfallchirurg ; 115(1): 33-4, 2012 Jan.
Artículo en Alemán | MEDLINE | ID: mdl-22274602

RESUMEN

The German S3 Guideline on Treatment of Polytrauma/Severely Injured Patients characterizes key recommendations on the current diagnostic and therapeutic approach in concomitant thoracic and abdominal trauma based on the available scientific data. The special requirements for appropriate basic treatment can be derived for rural hospitals, even though the particular grade of recommendation often is low because evidence-based studies are still lacking.The options for adequate basic treatment of thoracic and abdominal trauma in patients with multiple injuries treated in rural hospitals substantially depend on the dedication, the level of experience and training, and the willingness of the locally responsible team to cooperate.


Asunto(s)
Traumatismos Abdominales/cirugía , Hospitales Rurales/normas , Traumatismo Múltiple/cirugía , Guías de Práctica Clínica como Asunto , Competencia Profesional/normas , Traumatismos Torácicos/cirugía , Traumatología/normas , Alemania , Humanos
13.
Appl Environ Microbiol ; 77(11): 3896-7, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21498761

RESUMEN

We analyzed the prevalence of thermotolerant Campylobacter spp. compared that of to Salmonella spp. in raw yolk and on eggshells. A total of 2,710 eggs were investigated for each bacterium. Viable bacteria were found in 4.1% (Campylobacter spp.) and 1.1% (Salmonella spp.) of the eggshell samples, whereas the egg yolk samples were negative for both bacteria.


Asunto(s)
Campylobacter/aislamiento & purificación , Campylobacter/efectos de la radiación , Cáscara de Huevo/microbiología , Viabilidad Microbiana/efectos de la radiación , Salmonella/aislamiento & purificación , Salmonella/efectos de la radiación , Animales , Infecciones por Campylobacter/transmisión , Pollos , Yema de Huevo/microbiología , Enfermedades Transmitidas por los Alimentos , Calor , Infecciones por Salmonella/transmisión
14.
J Neural Transm (Vienna) ; 118(1): 7-21, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20865434

RESUMEN

Epithelial and endothelial tissue barriers are based on tight intercellular contacts (Tight Junctions, TJs) between neighbouring cells. TJs are multimeric complexes, located at the most apical border of the lateral membrane. So far, a plethora of proteins locating at tight intercellular contacts have been discovered, the role of which has just partly been unraveled. Yet, there is convincing evidence that many TJ proteins exert a dual role: They act as structural components at the junctional site and they are involved in signalling pathways leading to alterations of gene expression and cell behaviour (migration, proliferation). This review will shortly summarize the classical functions of TJs and TJ-related proteins and will introduce a new category, termed the "non-classical" functions of junctional proteins. A particular focus will be directed towards the nuclear targeting of junctional proteins and the downstream effects elicited by their intranuclear activities.


Asunto(s)
Uniones Estrechas/fisiología , Animales , Núcleo Celular/metabolismo , Endotelio/citología , Endotelio/fisiología , Células Epiteliales/metabolismo , Humanos , Proteínas de la Membrana/fisiología , Proteínas del Tejido Nervioso/fisiología , Uniones Estrechas/genética , Uniones Estrechas/metabolismo
15.
J Environ Monit ; 13(11): 3196-206, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22027805

RESUMEN

Smoke from residential wood burning has been identified as a major contributor to air pollution, motivating detailed emission measurements under controlled conditions. A series of experiments were performed to compare the emission levels from two types of wood-stoves to those of fireplaces. Eight types of biomass were burned in the laboratory: wood from seven species of trees grown in the Portuguese forest (Pinus pinaster, Eucalyptus globulus, Quercus suber, Acacia longifolia, Quercus faginea, Olea europaea and Quercus ilex rotundifolia) and briquettes produced from forest biomass waste. Average emission factors were in the ranges 27.5-99.2 g CO kg(-1), 552-1660 g CO(2) kg(-1), 0.66-1.34 g NO kg(-1), and 0.82-4.94 g hydrocarbons kg(-1) of biomass burned (dry basis). Average particle emission factors varied between 1.12 and 20.06 g kg(-1) biomass burned (dry basis), with higher burn rates producing significantly less particle mass per kg wood burned than the low burn rates. Particle mass emission factors from wood-stoves were lower than those from the fireplace. The average emission factors for organic and elemental carbon were in the intervals 0.24-10.1 and 0.18-0.68 g kg(-1) biomass burned (dry basis), respectively. The elemental carbon content of particles emitted from the energy-efficient "chimney type" logwood stove was substantially higher than in the conventional cast iron stove and fireplace, whereas the opposite was observed for the organic carbon fraction. Pinus pinaster, the only softwood species among all, was the biofuel with the lowest emissions of particles, CO, NO and hydrocarbons.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Biocombustibles/análisis , Carbono/análisis , Calefacción/métodos , Humo/análisis , Madera/química , Monitoreo del Ambiente , Calefacción/instrumentación , Portugal
17.
Acta Biomater ; 135: 243-259, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34509697

RESUMEN

In situ heart valve tissue engineering is an emerging approach in which resorbable, off-the-shelf available scaffolds are used to induce endogenous heart valve restoration. Such scaffolds are designed to recruit endogenous cells in vivo, which subsequently resorb polymer and produce and remodel new valvular tissue in situ. Recently, preclinical studies using electrospun supramolecular elastomeric valvular grafts have shown that this approach enables in situ regeneration of pulmonary valves with long-term functionality in vivo. However, the evolution and mechanisms of inflammation, polymer absorption and tissue regeneration are largely unknown, and adverse valve remodeling and intra- and inter-valvular variability have been reported. Therefore, the goal of the present study was to gain a mechanistic understanding of the in vivo regenerative processes by combining routine histology and immunohistochemistry, using a comprehensive sheep-specific antibody panel, with Raman microspectroscopy for the spatiotemporal analysis of in situ tissue-engineered pulmonary valves with follow-up to 24 months from a previous preclinical study in sheep. The analyses revealed a strong spatial heterogeneity in the influx of inflammatory cells, graft resorption, and foreign body giant cells. Collagen maturation occurred predominantly between 6 and 12 months after implantation, which was accompanied by a progressive switch to a more quiescent phenotype of infiltrating cells with properties of valvular interstitial cells. Variability among specimens in the extent of tissue remodeling was observed for follow-up times after 6 months. Taken together, these findings advance the understanding of key events and mechanisms in material-driven in situ heart valve tissue engineering. STATEMENT OF SIGNIFICANCE: This study describes for the first time the long-term in vivo inflammatory and regenerative processes that underly in situ heart valve tissue engineering using resorbable synthetic scaffolds. Using a unique combinatorial analysis of immunohistochemistry and Raman microspectroscopy, important spatiotemporal variability in graft resorption and tissue formation was pinpointed in in situ tissue-engineered heart valves, with a follow-up time of up to 24 months in sheep. This variability was correlated to heterogenous regional cellular repopulation, most likely instigated by region-specific differences in surrounding tissue and hemodynamics. The findings of this research contribute to the mechanistic understanding of in situ tissue engineering using resorbable synthetics, which is necessary to enable rational design of improved grafts, and ensure safe and robust clinical translation.


Asunto(s)
Estenosis de la Válvula Aórtica , Calcinosis , Prótesis Valvulares Cardíacas , Válvula Pulmonar , Implantes Absorbibles , Animales , Válvula Aórtica , Células Cultivadas , Válvulas Cardíacas , Ovinos , Ingeniería de Tejidos
18.
J Exp Med ; 123(6): 1013-24, 1966 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-5328828

RESUMEN

The immune response to bacteria and to a soluble protein was compared in germfree and conventionalized mice. Sixty germfree and 59 conventionalized mice received a suspension of killed Serratia marcescens into one front foot-pad and sterile horse ferritin into the other and were sacrificed in groups from 2 hr to 14 days after inoculation. All mice had no pre-existing antibody to either antigen and the flora of the conventionalized mice never contained Serratia. Lymphatic tissue changes and the fate of the antigens were followed in axillary lymph nodes and the spleens by histologic, fluorescent antibody, and autoradiographic techniques after tritiated thymidine injection. Individual serum antibody titers for both antigens were determined at each time period. The cellular and serologic responses were slightly delayed in the germfree mice but later equaled and sometimes exceeded those of the conventional animals. In all animals, lymph nodes draining the site of Serratia injection showed a more vigorous response than those on the ferritin-injected side but the reaction was qualitatively the same for both antigens. All lymph nodes contained the antigens by 2 hr after foot-pad injection. With time, both antigens lost their particulate nature sooner in conventionalized than in germfree macrophages. In the latter, both antigens persisted throughout the study while no longer demonstrable with fluoresceinated antiserum in conventional macrophages after the first week. While phagocytosis is equal in germfree and conventional mice, a greater digestive capacity of macrophages for antigens seems to result from the continuous exposure of conventional animals to the immunologic effects of the microbial flora. Conversely, the lack of substantial antigenic stimulation of lymphatic tissue in germfree animals fails to develop these macrophage functions beyond their basic ability to degrade foreign substances. Although the onset of the immune response is delayed in germfree mice, the relatively prolonged antigen digestion and the presumably slower release of immunogenic antigen fragments result in a more sustained and sometimes greater response than in conventional animals. This modifying effect of the microflora on the function of macrophages during the immune response is independent of previous experience with, or the nature of, the antigen.


Asunto(s)
Reacciones Antígeno-Anticuerpo , Antígenos , Vida Libre de Gérmenes , Macrófagos , Serratia marcescens , Animales , Ratones
19.
J Exp Med ; 123(2): 251-66, 1966 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-5905241

RESUMEN

Uremic colitis of varying severity occurred in the majority of conventionalized rats dying after removal of both kidneys, but was not found in uremic conventionalized and germfree rats sacrificed preterminally, or in germfree and limited-flora rats dying from uremia, or in any of the controls. The lesions were restricted to the cecum and their incidence and severity paralleled a shorter duration of survival. Cardiovascular damage including focal myocardial necrosis and calcification and patchy aortic and coronary calcification were observed in uremic rats regardless of their microbial status. These lesions had a higher incidence, developed more rapidly, and were more severe in the germfree and limited-flora rats than in the conventionalized animals. The presence or severity of the lesions, however, did not correlate with survival time of rats dying from uremia or with total plasma calcium and inorganic phosphorus levels of individual animals. Generalized necrotizing arteritis was not observed. Wound healing was poor in all uremic rats regardless of microbial status. Focal infection was noted in a few conventionalized rats dying from uremia, did not correlate with survival time, and was absent in all other groups. Comparison of biochemical findings between uremic germfree and conventionalized rats show a higher blood urea nitrogen and elevated plasma indoxyl sulfate in the presence of a microbial flora and a greater amount of plasma inorganic phosphorus in its absence. Uremia resulted in a decrease in hematocrit and increase in plasma and muscle potassium that were similar for germfree and conventionalized rats. Plasma and muscle sodium, total plasma calcium, glucose, and total protein were essentially unchanged by microbial status or uremia. Because the foregoing differences in the metabolic and histopathologic changes of uremia are linked to the known difference in microbial status of the fasting bilaterally-nephrectomized rats that were studied, they are a tangible indication of ways by which the indigenous microbial flora and its composition may affect the course of acute uremia.


Asunto(s)
Sistema Cardiovascular/patología , Vida Libre de Gérmenes , Intestinos , Uremia , Animales , Nitrógeno de la Urea Sanguínea , Ciego/patología , Ayuno , Nefrectomía , Fósforo , Potasio , Ratas
20.
Phys Rev Lett ; 105(6): 067208, 2010 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-20868008

RESUMEN

All-electrical spin-wave spectroscopy, Brillouin light scattering, as well as the magneto-optical Kerr effect are combined to study spin-wave propagation through a magnetic antidot lattice nanopatterned into a Ni(80)Fe(20) thin film. The propagation velocities and, in particular, the relaxation are found to depend characteristically on the applied in-plane magnetic field. We explain the observed anisotropies by magnetic field-controlled spin-wave guiding in a network of interconnected nanowires which takes place over distances of up to 20 µm.

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