RESUMEN
Parkinson's disease (PD) is a progressive, degenerative disease that affects nearly 10 million people worldwide. Hallmark limb motor signs and dopamine depletion have been well studied; however, few studies evaluating early stage, prodromal biology exist. Pink1-/- rats, a rodent model of PD mitochondrial dysfunction, exhibit early stage behavioral deficits, including vocal communication and anxiety, that progress during mid-to-late adulthood (6-12 months of age). Yet, the biological pathways and mechanisms that lead to prodromal dysfunction are not well understood. This study investigated the Pink1-/- rat in young adulthood (2 months of age). Mixed sex groups of Pink1-/- rats and wildtype (WT) controls were assayed for limb motor, anxiety, and vocal motor behaviors. A customized NanoString CodeSet, based on genetic work in later adulthood, was used to probe for the up regulation of genes involved in disease pathways and inflammation within the brainstem and vocal fold muscle. In summary, the data show sex- and genotype-differences in limb motor, anxiety, and vocal motor behaviors. Specifically, female Pink1-/- rats demonstrate less anxiety-like behavior compared to male Pink1-/- rats and female rats show increased locomotor activity compared to male rats. Pink1-/- rats also demonstrate prodromal ultrasonic vocalization dysfunction across all acoustic parameters and sex differences were present for intensity (loudness) and peak frequency. These data demonstrate a difference in phenotype in the Pink1-/- model. Tuba1c transcript level was identified as a key marker negatively correlated to ultrasonic vocalization at 2 months of age. Identifying genes, such as Tuba1c, may help determine early predictors of PD pathology in the Pink1-/- rat and serve as targets for future drug therapy studies.
RESUMEN
An 8-month-old intact female pug was presented for evaluation and possible balloon valvuloplasty (BV) for severe aortic stenosis. A bicuspid, severely stenotic aortic valve of type 3 morphology with a supravalvar stenosis component was diagnosed, consistent with the diagnosis of atypical Shone's complex. There was severe concentric hypertrophy of the left ventricle, with increased echogenicity of the myocardium nearest to the endocardial border. Mild left atrial enlargement was observed. Selective angiography and transesophageal echocardiography revealed an enlarged and relatively tortuous ascending aorta. The changes to the ascending aorta and the anatomy of the lesion made retrograde access to the left ventricle challenging. Ultimately, BV was successful using a pediatric valvuloplasty balloon catheter and rapid right ventricular pacing, and the pressure gradient across the aortic valve was decreased by more than 50% compared with preoperative measurements. Although valvar aortic stenosis is rare in veterinary medicine, this report highlights the potential challenges and feasibility of BV for this disease.
Asunto(s)
Estenosis Aórtica Supravalvular/veterinaria , Válvula Aórtica/anomalías , Valvuloplastia con Balón/veterinaria , Enfermedades de los Perros/terapia , Enfermedades de las Válvulas Cardíacas/veterinaria , Animales , Estenosis Aórtica Supravalvular/diagnóstico por imagen , Estenosis Aórtica Supravalvular/terapia , Válvula Aórtica/diagnóstico por imagen , Enfermedad de la Válvula Aórtica Bicúspide , Enfermedades de los Perros/diagnóstico por imagen , Perros , Ecocardiografía/veterinaria , Ecocardiografía Transesofágica/veterinaria , Femenino , Enfermedades de las Válvulas Cardíacas/diagnóstico por imagen , Enfermedades de las Válvulas Cardíacas/terapiaRESUMEN
OBJECTIVES: To investigate the outcome of dogs with central nervous system lymphoma. MATERIALS AND METHODS: A multi-center, retrospective, observational study was conducted by reviewing medical records of 18 cases of central nervous system lymphoma from seven institutions. RESULTS: Diagnosis of lymphoma was made through cerebrospinal fluid analysis, histopathology, flow cytometry of the cerebrospinal fluid, and cytology of cerebrospinal fluid, lymph node or spleen with correlated imaging. A total of 15 of 18 dogs received specific treatment other than prednisone. Three dogs underwent chemotherapy and radiation therapy after surgical decompression, five dogs underwent chemotherapy, two dogs underwent radiation therapy after surgical decompression, three dogs underwent chemotherapy after surgical decompression and two dogs underwent radiation therapy and chemotherapy. Only one dog received prednisone, and two dogs did not receive any treatment. Overall, the median survival time was 171 days (range 1 to 1942 days). CLINICAL SIGNIFICANCE: Dogs receiving any type of treatment for central nervous system lymphoma lived longer than cases described in previous historical reports. Further studies are needed to elucidate the importance of specific treatment modalities.
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Neoplasias del Sistema Nervioso Central/veterinaria , Enfermedades de los Perros/terapia , Linfoma/veterinaria , Animales , Antiinflamatorios/administración & dosificación , Neoplasias del Sistema Nervioso Central/diagnóstico , Neoplasias del Sistema Nervioso Central/terapia , Descompresión Quirúrgica/veterinaria , Enfermedades de los Perros/diagnóstico , Perros , Femenino , Linfoma/diagnóstico , Linfoma/terapia , Masculino , Prednisona/administración & dosificación , Estudios Retrospectivos , Análisis de SupervivenciaRESUMEN
BACKGROUND: Systemic aspergillosis is a manifestation of Aspergillus sp. infection that can result in central nervous system (CNS) involvement with marked alterations in CNS function. Information regarding the clinical presentation and magnetic resonance imaging (MRI) findings in cases of aspergillosis with CNS involvement is lacking, resulting in a need for better understanding of this disease. HYPOTHESIS/OBJECTIVES: The primary objectives were to describe the clinical features and MRI findings in dogs with CNS aspergillosis. The secondary objectives were to describe clinicopathologic findings and case outcome. ANIMALS: Seven dogs with CNS aspergillosis. METHODS: Archived records from 6 institutions were reviewed to identify cases with MRI of CNS aspergillosis confirmed with serum galactomannan enzyme immunoassay (EIA) testing, culture, or supported by histopathology. Signalment, clinical, MRI, clinicopathologic, histopathologic, and microbiologic findings were recorded and evaluated. RESULTS: Aspergillosis of the CNS was identified in 7 dogs from 3 institutions. The median age was 3 years and six were German Shepherd dogs. Five dogs had signs of vestibular dysfunction as a component of multifocal neurological abnormalities. The MRI findings ranged from normal to abnormal, including hemorrhagic infarction and mass lesions. CONCLUSIONS AND CLINICAL IMPORTANCE: Until now, all reported MRI findings in dogs with CNS aspergillosis have been abnormal. We document that CNS aspergillosis in dogs, particularly German Shepherd dogs, can be suspected based on neurologic signs, whether MRI findings are normal or abnormal. Confirmatory testing with galactomannan EIA, urine, cerebrospinal fluid (CSF) or tissue culture should be performed in cases where aspergillosis is a differential diagnosis.
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Aspergilosis/veterinaria , Infecciones Fúngicas del Sistema Nervioso Central/veterinaria , Enfermedades de los Perros/patología , Imagen por Resonancia Magnética/veterinaria , Animales , Antifúngicos/uso terapéutico , Aspergilosis/diagnóstico , Aspergilosis/patología , Infecciones Fúngicas del Sistema Nervioso Central/patología , Enfermedades de los Perros/diagnóstico , Perros , Femenino , MasculinoRESUMEN
The objective of this study was to determine if maternal energy status during mid-gestation influences the expression of genes regulating muscle and fat development, and muscle characteristics that may impact meat tenderness. Cows grazed dormant, native range (Positive Energy Status [PES]) or were fed at 80% of maintenance energy requirements (Negative Energy Status [NES]) during mid-gestation. Steer offspring were harvested after 21 d in the feedlot (weaning subsample) or after 208 d in the feedlot (final subsample). Greater 21-d tenderness was observed in NES steers, resulting from reduced collagen content in longissimus lumborum steaks. In the semitendinosus, NES steers had greater soluble collagen, and down-regulated expression of MHC-IIA and TIMP-3 at weaning, while MHC-IIA expression was up-regulated in NES steers in the final harvest. Data show mid-gestational maternal energy status may impact offspring tenderness and collagen, but differences were not detected in expression of genes important in myogenesis and adipogenesis in muscle samples obtained from steers at weaning or slaughter.
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Metabolismo Energético , Regulación de la Expresión Génica/fisiología , Carne/normas , Músculo Esquelético/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Bovinos , Femenino , Fenómenos Fisiologicos Nutricionales Maternos , EmbarazoRESUMEN
Research has suggested that maternal undernutrition may cause the development of a thrifty phenotype in the offspring, potentially resulting in greater adiposity and reduced muscle mass. These alterations in adipose and muscle development could have lasting impacts on offspring growth, carcass characteristics, and meat quality. However, limited research exists evaluating the impact of maternal energy status on these economically important traits of the offspring. Therefore, the objective of this study was to determine the influence of maternal energy status during midgestation on offspring carcass characteristics and meat quality. To alter maternal energy status, cows either grazed dormant, winter range (positive energy status [PES]) or were fed in a drylot at 80% of the energy requirements for BW maintenance (negative energy status [NES]) during a mean period of 102 ± 10.9 to 193 ± 10.9 d of gestation. Changes in BCS, BW, LM area (LMA), and 12th rib backfat were measured throughout midgestation. At the end of midgestation, cows in the NES group had a reduction (P ≤ 0.05) in BCS, BW, LMA, and 12th rib backfat when compared with PES dams. Cows and calves were managed similarly after midgestation through weaning and calves were managed and fed a common diet through the receiving, backgrounding, and finishing phases in the feedlot. Calves were harvested after 208 d in the feedlot, carcass characteristics were recorded, and strip loins were recovered for analysis of objective color and Warner-Bratzler shear force (WBSF). Maternal energy status had no influence on offspring HCW, dressing percent, LMA, percent KPH, marbling score, percent intramuscular fat, objective color, or WBSF (P > 0.10). Progeny of NES cows tended to have improvements in 12th rib backfat and USDA yield grade (P < 0.10). Greater ratio of marbling score to 12th rib fat thickness and ratio of percent intramuscular fat to 12th rib fat thickness (P < 0.05) were discovered in progeny from cows experiencing a NES during midgestation. These results suggest that maternal energy status during midgestation may impact fat deposition in intramuscular and subcutaneous fat depots without impacting muscle mass.
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Animales Recién Nacidos/fisiología , Composición Corporal/fisiología , Bovinos/fisiología , Metabolismo Energético/fisiología , Fenómenos Fisiologicos Nutricionales Maternos/fisiología , Carne/normas , Preñez/fisiología , Adiposidad/fisiología , Animales , Animales Recién Nacidos/crecimiento & desarrollo , Peso Corporal/fisiología , Bovinos/crecimiento & desarrollo , Femenino , Desarrollo Fetal/fisiología , Industria de Alimentos/normas , Calidad de los Alimentos , Masculino , Músculo Esquelético/fisiología , EmbarazoRESUMEN
The Tertiary Limestone Aquifer (TLA) is one of the major regional hydrogeological systems of southern Australia. Submarine groundwater discharge (SGD) of freshwater from the TLA occurs through spring creeks, beach springs and diffusively through beach sands, but the magnitude of the total flux is not known. Here, a range of potential environmental tracers (including temperature, salinity, (222)Rn, (223)Ra, (224)Ra, (226)Ra, (228)Ra, and (4)He) were measured in potential sources of SGD and in seawater along a 45 km transect off the coastline to evaluate SGD from the TLA. Whilst most tracers had a distinct signature in the sources of water to the coastline, salinity and the radium quartet had the most distinct SGD signal in seawater. A one-dimensional advection-dispersion model was used to estimate the terrestrial freshwater component of SGD (Qfw) using salinity and the recirculated seawater component (Qrsw) using radium activity in seawater. Qfw was estimated at 1.2-4.6 m(3) s(-1), similar in magnitude to previously measured spring creek discharge (â¼3 m(3) s(-1)) for the area. This suggests that other terrestrial groundwater discharge processes (beach springs and diffuse discharge through beach sands) were no more than 50% of spring creek discharge. The largest component of total SGD was Qrsw, estimated at 500-1000 m(3) s(-1) and possibly greater. The potential for wave, storm, or buoyancy-driven porewater displacement from the seafloor could explain the large recirculation flux for this section of the Southern Ocean Continental Shelf.
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Agua Subterránea/análisis , Radio (Elemento)/análisis , Radón/análisis , AustraliaRESUMEN
The incidence of anxiety, mood, substance abuse disorders and schizophrenia increases during adolescence. Epidemiological evidence confirms that exposure to stress during sensitive periods of development can create vulnerabilities that put genetically predisposed individuals at increased risk for psychiatric disorders. Neuregulin 1 (NRG1) is a frequently identified schizophrenia susceptibility gene that has also been associated with the psychotic features of bipolar disorder. Previously, we established that Type II NRG1 is expressed in the hypothalamic-pituitary-adrenal (HPA) axis neurocircuitry. We also found, using a line of Nrg1 hypomorphic rats (Nrg1(Tn)), that genetic disruption of Type II NRG1 results in altered HPA axis function and environmental reactivity. The present studies used the Nrg1(Tn) rats to test whether Type II NRG1 gene disruption and chronic stress exposure during adolescence interact to alter adult anxiety- and fear-related behaviors. Male and female Nrg1(Tn) and wild-type rats were exposed to chronic variable stress (CVS) during mid-adolescence and then tested for anxiety-like behavior, cued fear conditioning and basal corticosterone secretion in adulthood. The disruption of Type II NRG1 alone significantly impacts rat anxiety-related behavior by reversing normal sex-related differences and impairs the ability to acquire cued fear conditioning. Sex-specific interactions between genotype and adolescent stress also were identified such that CVS-treated wild-type females exhibited a slight reduction in anxiety-like behavior and basal corticosterone, while CVS-treated Nrg1(Tn) females exhibited a significant increase in cued fear extinction. These studies confirm the importance of Type II NRG1 in anxiety and fear behaviors and point to adolescence as a time when stressful experiences can shape adult behavior and HPA axis function.
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Ansiedad/genética , Ansiedad/metabolismo , Miedo/fisiología , Neurregulina-1/deficiencia , Neurregulina-1/genética , Glándulas Suprarrenales/fisiología , Factores de Edad , Animales , Ansiedad/psicología , Enfermedad Crónica , Miedo/psicología , Femenino , Hipotálamo/fisiología , Masculino , Hipófisis/fisiología , Ratas , Ratas Endogámicas F344 , Ratas TransgénicasRESUMEN
For sectioned biologic tissues, atomic force microscopy (AFM) topographic images alone hardly provide adequate information leading to revealing biological structures. We demonstrate that phase imaging in amplitude-modulation AFM is a powerful tool in mapping structures present on the surface of unfixed rat brains sections. The contrast in phase images is originated from the difference in mechanical properties between biological structures. Visualization of the native state of biological structures by way of their mechanical properties provides a complementary technique to more traditional imaging techniques such as optical and electron microscopy.
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Encéfalo/ultraestructura , Microscopía de Fuerza Atómica/métodos , Animales , Encéfalo/anatomía & histología , Lípidos/análisis , Masculino , Microscopía de Fuerza Atómica/instrumentación , Ratas , Ratas Long-Evans , Espectrometría de Masa de Ion SecundarioRESUMEN
Exposure to stress can result in an increased risk for psychiatric disorders, especially among genetically predisposed individuals. Neuregulin 1 (NRG1) is a susceptibility gene for schizophrenia and is also associated with psychotic bipolar disorder. In the rat, the neurons of the hypothalamic paraventricular nucleus show strong expression of Nrg1 mRNA. In patients with schizophrenia, a single nucleotide polymorphism in the 5' region of NRG1 interacts with psychosocial stress to affect reactivity to expressed emotion. However, there is virtually no information on the role of NRG1 in hypothalamic-pituitary-adrenal axis function, and whether the protein is expressed in the paraventricular nucleus is unknown. The present studies utilize a unique line of Nrg1 hypomorphic rats (Nrg1(Tn)) generated by gene trapping with the Sleeping Beauty transposon. We first established that the Nrg1(Tn) rats displayed reduced expression of both the mRNA and protein corresponding to the Type II NRG1 isoform. After confirming, using wild type animals, that Type II NRG1 is expressed in the neurocircuitry involved in regulating hypothalamic-pituitary-adrenal axis responses to environmental stimuli, the Nrg1(Tn) rats were then used to test the hypothesis that altered expression of Type II NRG1 disrupts stress regulation and reactivity. In support of this hypothesis, Nrg1(Tn) rats have disrupted basal and acute stress recovery corticosterone secretion, differential changes in expression of glucocorticoid receptors in the pituitary, paraventricular nucleus and hippocampus, and a failure to habituate to an open field. Together, these findings point to NRG1 as a potential novel regulator of neuroendocrine responses to stress as well as behavioral reactivity.
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Conducta Animal/fisiología , Ambiente , Sistema Hipotálamo-Hipofisario/metabolismo , Neurregulina-1/genética , Neurregulina-1/metabolismo , Sistema Hipófiso-Suprarrenal/metabolismo , Análisis de Varianza , Animales , Animales Recién Nacidos , Corticosterona/metabolismo , Conducta Exploratoria/fisiología , Femenino , Glucocorticoides/metabolismo , Habituación Psicofisiológica/fisiología , Masculino , Conducta Materna/fisiología , Mutación/genética , ARN Mensajero/metabolismo , Radioinmunoensayo/métodos , Ratas , Ratas Endogámicas F344 , Ratas Transgénicas , Receptores de Mineralocorticoides/metabolismo , Restricción Física/métodosRESUMEN
Recruitment of individuals of the marine alga Ulva linza on to a suitable habitat involves the settlement of motile zoospores on to a substratum during which a preformed adhesive is secreted by vesicular exocytosis. The fluorescent styryl dye FM 1-43 and fluorescent Ca(2+) indicators were used to follow membrane cycling and changes in cytosolic Ca(2+) ([Ca(2+)](cyt)) associated with settlement. When swimming zoospores were exposed continuously to FM 1-43, the plasma membrane was preferentially labelled. During settlement, FM 1-43-labelled plasma membrane was rapidly internalized reflecting high membrane turnover. The internalized membrane was focused into a discrete region indicating targeting of membrane to an endosome-like compartment. Acetoxymethyl (AM)-ester derivatives were found to be unsuitable for monitoring [Ca(2+)](cyt) because the dyes were rapidly sequestered from the cytoplasm into sub-cellular compartments. [Ca(2+)](cyt) was, however, reliably measured using dextran-conjugated calcium indicators delivered into cells using a biolistic technique. Cells loaded with Oregon Green BAPTA-1 dextran (Invitrogen, Paisley, UK) showed diffuse cytosolic loading and reliably responded to imposed changes in [Ca(2+)](cyt). During settlement, zoospores exhibited both localized and diffuse increases in [Ca(2+)](cyt) implying a role for [Ca(2+)](cyt) in exocytosis of the adhesive.
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Calcio/metabolismo , Adhesión Celular , Chlorophyta/fisiología , Endocitosis , Esporas , Membrana Celular/metabolismo , Membrana Celular/fisiología , Chlorophyta/metabolismoRESUMEN
Increased incidence of malignancies within aviators is well documented. Commercial female flyers have been found to have a higher risk of developing breast cancer. However, there has not been any report of male breast cancer related to flying either alone or where malignant melanoma and other primary cancers are also associated. We report two male World War II, British Royal Air Force pilots with primary breast carcinoma associated with two other primary cancer sites.
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Aviación , Neoplasias de la Mama Masculina/diagnóstico , Carcinoma Ductal de Mama/patología , Anciano , Biopsia con Aguja , Neoplasias de la Mama Masculina/terapia , Carcinoma Ductal de Mama/terapia , Quimioterapia Adyuvante , Estudios de Seguimiento , Humanos , Masculino , Mastectomía/métodos , Estadificación de Neoplasias , Medición de Riesgo , Resultado del Tratamiento , GuerraAsunto(s)
Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/patología , Carcinoma Lobular/secundario , Neoplasias Endometriales/secundario , Biopsia , Carcinoma Lobular/diagnóstico , Neoplasias Endometriales/diagnóstico , Endometrio/patología , Femenino , Humanos , Histeroscopía , Persona de Mediana EdadRESUMEN
In guard cells, membrane hyperpolarization in response to a blue light (BL) stimulus is achieved by the activation of a plasma membrane H(+)-ATPase. Using the patch clamp technique on broad bean (Vicia faba) guard cells we demonstrate that both steady-state- and BL-induced pump currents require ATP and are blocked by vanadate perfused into the guard cell during patch clamp recording. Background-pump current and BL-activated currents are voltage independent over a wide range of membrane potentials. During BL-activated responses significant hyperpolarization is achieved that is sufficient to promote K(+) uptake. BL activation of pump current becomes desensitized by three or four pulses of 30 s x 100 micromol m(-2) s(-1) BL. This desensitization is not a result of pump inhibition as maximal responses to fusicoccin are observed after full BL desensitization. BL treatments prior to whole cell recording show that BL desensitization is not due to washout of a secondary messenger by whole cell perfusion, but appears to be an important feature of the BL-stimulated pump response. We found no evidence for an electrogenic BL-stimulated redox chain in the plasma membrane of guard cells as no steady-state- or BL-activated currents are detected with NADH or NADPH added to the cytosol in the absence of ATP. Steady-state- nor BL-activated currents are affected by the inclusion along with ATP of 1 mM NADH in the pipette under saturating red light or by including NADPH in the pipette under darkness or saturating red light. These data suggest that reduced products of photosynthesis do not significantly modulate plasma membrane pump currents and are unlikely to be critical regulators in BL-stimulation of the plasma membrane H(+)-ATPase in guard cells.
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Bombas de Protones/fisiología , Vicia faba/fisiología , Membrana Celular/fisiología , Membrana Celular/efectos de la radiación , Oscuridad , Luz , Potenciales de la Membrana/fisiología , Potenciales de la Membrana/efectos de la radiación , NAD/metabolismo , NADP/metabolismo , Oxidación-Reducción , Técnicas de Placa-Clamp , ATPasas de Translocación de Protón/metabolismo , Vicia faba/citología , Vicia faba/efectos de la radiaciónRESUMEN
Breast conservation surgery is now widely accepted as the treatment of choice in early breast cancer. Randomised controlled trials have shown comparable recurrence and survival rates following breast conservation when compared to mastectomy, with the perceived advantage that it should leave a cosmetically acceptable result without reconstruction. It is our experience that an adequate local excision may result in a poor cosmetic result with distortion of the nipple position, especially in women with small breasts. Between January 1994 and July 1996, we have performed 30 procedures, combining a wide local excision and axillary lymph node clearance for breast cancer with immediate reconstruction of the defect with a latissimus dorsi musculocutaneous flap. All patients had postoperative radiotherapy to the residual breast and, where appropriate, to the axilla. Adjuvant hormonal therapy or chemotherapy was prescribed where indicated. Patient's ages ranged from 36 to 72 years. All tumours were in the lateral, superior or inferior quadrants. The mean combined operating time was 120 min. Two patients required postoperative blood transfusion. Mean hospital stay was 8 days. Histology confirmed tumour clearance in all cases and six patients had axillary lymph node metastases. There were two cases of minor wound infection and six cases of seroma at the donor site. We conclude that breast cancers are ideally treated by a multidisciplinary team and that an immediate latissimus dorsi musculocutaneous flap may correct the deformities often seen after breast conservation surgery.
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Neoplasias de la Mama/cirugía , Mamoplastia/métodos , Músculo Esquelético/trasplante , Trasplante de Piel , Colgajos Quirúrgicos , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Escisión del Ganglio Linfático , Mastectomía Segmentaria , Persona de Mediana EdadRESUMEN
High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.
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Patch-clamp technology has greatly increased our knowledge of plant membrane transport. However, the success of patch clamping crucially relies on establishing a high resistance (G omega) seal between the membrane and the patch-clamp pipette. This can prove problematic in many plant-cell preparations. It is therefore of great importance to develop protocols for protoplast isolation, maintenance and seal formation that improve seal rate. This study investigated whether the pH and the K+ and the Cl(-)concentration of the pipette solution had an effect on the seal formation. High pH and absence of K+ significantly promoted membrane sealing, whereas the concentration of Cl- had no effect. To reap the benefit of seal-promoting pipette solutions and yet retain the option to adjust this solution to experimental requirements, a pipette perfusion apparatus was implemented. The perfusion system was successfully applied in cell-attached patch, excised-patch and whole-cell configurations, using plasma membrane and tonoplast of three different species. The system enables complete solution exchange within minutes and is potentially of great benefit in the study of channel selectivity, the application of (cytoplasmic) channel blockers and the study of primary and secondary transport.