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1.
Although the beta2 adrenergic agonists have been seen to have important effects on the mechanisms regulating the development and death of T-cells in the thymus, the side-effects on the immune system of anabolic treatments of these substances have hardly been considered. In order to evaluate the effects exerted by the beta2 adrenergic agonist clenbuterol on the thymocyte population, the thymus of eight pigs treated with anabolic doses of this substance was studied by morphometric methods, regarding apoptotic (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL)-positive) and normal (TUNEL-negative) cells. The thymus of another eight pigs fed without clenbuterol served as a control. The clenbuterol treatment had a clear effect on the thymocyte size, decreasing their mean nuclear area. The T-cell apoptosis index was also affected by the clenbuterol, significantly increasing the apoptosis percentage in the treated group with respect to the control. In the light of our results, the clenbuterol induced thymocyte apoptosis throughout the thymus and caused morphometric changes in the thymocyte population, which was in line with the immunosuppressive role attributed to other beta2 adrenergic agonists.  相似文献   
2.
A 6-year-old female Alaska Malamute dog was presented for evaluation of abdominal enlargement referred by a local veterinarian. On the history, the owner complained of chronic abdominal enlargement initiated more than 4 months ago, reduced appetite, occasional vomiting and general dullness. He also complained of greenish mucous intermittent vaginal discharge starting 10 days ago. The bitch was chronically treated with medroxiprogesterone acetate. A laparatomy was performed and fluid in the abdomen was found and aspirated during the surgery. Also a very fluid-filled distended uterus and a mass in the distal part of the left uterine horn were found. The mass was encapsulated by the omentum, but areas of necrosis and calcification were identified. Histopathological diagnosis was endometrial adenocarcinoma.  相似文献   
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A sensitive and quick method was developed to determine the presence of α-amylase in the gut of aquatic organisms, as well as its sensitivity to inhibitors. The assay is based on the utilization of Petri dishes filled with starch–agarose gel as a substrate for the enzyme solution, which is placed in small wells punched in the surface. Circular zones produced by the action of amylase remain colourless after staining with lugol. Pure commercial porcine amylase was used to fit the better conditions for developing the assay (1 g L–1 starch in the gels, 4 h of incubation). The diameter of the cleared zones were related to the activity of enzyme and the method detected linearly amylase activity in a range of 2–20 U well–1, so it was used to reveal the presence of amylase in digestive extracts obtained from different sparid fish. The method was also used to evaluate the effect produced by a specific inhibitor on fish amylases, showing a linear response when the ratio inhibitor:enzyme (in units) changed from 20:1 to 2:1. Comparison of the cleared zones produced by amylases of sparid fish in the presence or absence of inhibitor, revealed differences in their sensitivity to inhibition, which ranged from 15 to 50% of total activity. The assay is proposed for a preliminary evaluation of possible inhibitors contained in feedstuffs used in fish feeding.  相似文献   
6.
Agricultural productivity is worldwide subjected to increasing salinity problems. Various strategies are applied to overcome the deleterious effects of salinity on plants. This study was conducted in order to determine whether drought pretreatment of seedlings or seed pretreatment with NaCl increases the long‐term salinity resistance of tomato (Solanum lycopersicum L.) and whether the adaptive response to salinity is accompanied by physiological changes throughout the plant‐growth cycle. When plants were pretreated at the five‐leaf growth stage, the plant dry weight was significantly higher in drought‐pretreated than in non‐pretreated plants after 50 d of salt treatment. The positive effect of drought pretreatment applied at the five‐leaf stage was maintained throughout the entire growth cycle, as fruit yield of drought‐pretreated plants was 40% higher than that of non‐pretreated plants at the end of the harvest period (150 d of 70 mM NaCl treatment). Moreover, the most productive plants maintained lower Na+ and Cl accumulation in their leaves until the end of the growth cycle, which shows that adaptation is a long‐term response during which the plants adjust their physiology to the environmental conditions. Salt resistance was also improved through seed pretreatment with NaCl. In conclusion, drought pretreatment applied at the five‐leaf stage or seed pretreatment with NaCl provide an alternative way to enhance salt resistance in tomato, and the increase in yield is associated with physiological changes throughout the plant‐growth cycle.  相似文献   
7.
The preparation and analysis of inorganic-organic polymer nanocomposites consisting of inorganic nanowires and multiwire "cables" in a random-coil organic polymer host is reported. Dissolution of inorganic (LiMo3Se3)n wires in a strongly coordinating monomer, vinylene carbonate, and the use of a rapid polymerization in the presence of a cross-linking agent produce nanocomposites without phase separation. Polymerization of dilute solutions yields a material containing mostly (Mo3Se3(-))n mono- and biwires, 6 to 20 angstroms in diameter and 50 to 100 nanometers long. Polymerization of more concentrated liquid crystalline solutions yields a nanocomposite containing oriented multiwire cables, 20 to 40 angstroms in diameter and up to 1500 nanometers long, that display optical anisotropy and electrical conductivity.  相似文献   
8.
The effect of an acceleration assay, carried out with a periodic aeration and an increased surface/volume ratio, on various aroma compounds of "fino" Sherry wines aging under a veil of a pure culture of Saccharomyces cerevisiae race capensis G1 flor film yeast was studied. The results were subjected to multifactor analysis of variance, and the compounds simultaneously depending on acceleration conditions and aging time at p < 0.01 were subjected to principal component analysis. The first component, accounting for 86.14% of the overall variance, was mainly defined by acetaldehyde and its derivatives 1,1-diethoxyethane and acetoin. These compounds reached higher concentrations in accelerated aging wines in a shorter time than they did in control wines, and no browning problems were detected. Taking into account that these compounds can be used as indicators for biological aging of "fino" Sherry wines, the acceleration condition assayed can be applied to shorten the time of this process.  相似文献   
9.
Purkinje cerebellar cells were studied in three Arabian horses aged between 6 and 8 months with clinical disorders in their movements, tremors and ataxia; the occurrence of apoptosis in this cell population was investigated by the (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labelling (TUNEL) method. Both optical and electron microscopical images showed a scant number of Purkinje cells, most of them with morphological features of apoptosis such as condensation of the nucleus and cytoplasm as well as segregation and fragmentation of the nucleus into apoptotic bodies. The TUNEL technique revealed a substantial number (65%) of positive immunoreactive Purkinje cells.  相似文献   
10.
Abstract

The intensive forest use has caused a significant transformation around the world. Sustainable forest management (SFM) has emerged as an alternative to address concerns regarding resource use, conservation, and socioeconomic benefits. Evidence suggests that its application remains inconsistent. In Argentina, the national government passed a law addressing management aiming to provide guidelines and incentives to steer practices into a sustainable framework. The objectives were: (a) understand what the concept of SFM means to participants in Tierra del Fuego; (b) identify and assess how different factors influence the adoption of SFM; (c) review the stakeholder perceptions on recent regulatory changes; and (d) identify the steps required for improving management. We conducted 52 semi-structured interviews with stakeholders and parties at the national level. New regulatory arrangements were implemented for a short-time before this research was undertaken, and we could not evaluate the success of reform. The study provided deep insight into the policy-making process, and the views held by different stakeholders. The historical mismanagement of the resource, together with an unfavorable past relationship with authorities, has promoted short-term perspectives which resulted in behaviors inconsistent with SFM. Moreover, the characteristic demographic composition brings a social component not identified in the broader literature as relevant for SFM adoption.  相似文献   
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