990 resultados para charged particle dynamics


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Previous studies have suggested that abnormal corneal wound healing in patients after photorefractive keratectomy (PRK) is associated with the appearance of myofibroblasts in the stroma between two and four weeks after surgery. The purpose of this study was to examine potential myofibroblast progenitor cells that might express other filament markers prior to completion of the differentiation pathway that yields alpha-smooth muscle actin (SMA)-expressing myofibroblasts associated with haze localized beneath the epithelial basement membrane after PRK. Twenty-four female rabbits that had -9 diopter PRK were sacrificed at 1 week, 2 weeks, 3 weeks or 4 weeks after surgery. Corneal rims were collected, frozen at -80 degrees C, and analyzed by immunocytochemistry using anti-vimentin, anti-desmin, and anti-SMA antibodies. Double immunostaining was performed for the co-localization of SMA with vimentin or desmin with SMA. An increase in vimentin expression in stromal cells is noted as early as 1 week after PRK in the rabbit cornea. As the healing response continues at two or three weeks after surgery, many stromal cells expressing vimentin also begin to express desmin and SMA. By 4 weeks after the surgery most, if not all, myofibroblasts express vimentin, desmin and SMA. Generalized least squares regression analysis showed that there was strong evidence that each of the marker groups differed in expression over time compared to the other two (p < 0.01). Intermediate filaments - vimentin and desmin co-exist in myofibroblasts along with SMA and may play an important role in corneal remodeling after photorefractive keratectomy. The earliest precursors of myofibroblasts destined to express SMA and desmin are detectible by staining for vimentin at 1 week after surgery. (C) 2009 Elsevier Ltd. All rights reserved.

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Previous studies have suggested that abnormal corneal wound healing in patients after photorefractive keratectomy (PRK) is associated with the appearance of myofibroblasts in the stroma between two and four weeks after surgery. The purpose of this study was to examine potential myofibroblast progenitor cells that might express other filament markers prior to completion of the differentiation pathway that yields a-smooth muscle actin (SMA)-expressing myofibroblasts associated with haze localized beneath the epithelial basement membrane after PRK. Twenty-four female rabbits that had -9 diopter PRK were sacrificed at I week, 2 weeks, 3 weeks or 4 weeks after surgery. Corneal rims were collected, frozen at -80 degrees C, and analyzed by immunocytochemistry using anti-vimentin, anti-desmin, and anti-SMA antibodies. Double immunostaining was performed for the co-localization of SMA with vimentin or desmin with SMA. An increase in vimentin expression in stromal cells is noted as early as 1 week after PRK in the rabbit cornea. As the healing response continues at two or three weeks after surgery, many stromal cells expressing vimentin also begin to express desmin and SMA. By 4 weeks after the surgery most, if not all, myofibroblasts express vimentin, desmin and SMA. Generalized least squares regression analysis showed that there was strong evidence that each of the marker groups differed in expression over time compared to the other two (p < 0.01). Intermediate filaments - vimentin and desmin co-exist in myofibroblasts along with SMA and may play an important role in corneal remodeling after photorefractive keratectomy. The earliest precursors of myofibroblasts destined to express SMA and desmin are detectible by staining for vimentin at I week after surgery. (C) 2009 Elsevier Ltd. All rights reserved.

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Secondary hyperparathyroidism is a common complication in uremic patients. Total parathyroidectomy combined with partial autotransplantation into brachioradialis muscle has been the preference among the options for surgical treatment. This study was designed to evaluate the reserve and ability of suppression of autotransplanted parathyroid tissue using dynamics tests. We studied, prospectively, 12 patients in recent (RP) and late (LP) postoperative of total parathyroidectomy with autotransplantation. For analysis of the secretory reserve capacity, we induced hypocalcemia by ethylenediaminetetraacetic acid (EDTA) infusion. Furthermore, for analysis of the ability for parathyroid hormone (PTH) suppression, the hypercalcemia test was used, by intravenous administration of calcium in LP. In RP, there was a decrease in the average serum levels of PTH, phosphorus, and alkaline phosphatase, which ranged from 13 to 231 (87 +/- A 65) pg/ml, 2.3 to 6.2 (3.3 +/- A 1.1) mg/dl, and 77 to 504 (250 +/- A 135) U/L, respectively, similar to that observed in LP. The analysis of the average curve of variations in PTH during testing of the stimulus with EDTA showed lack of secretion in RP and partial response in LP. Impaired suppression ability of the graft in LP was observed in the test with intravenous calcium. Total parathyroidectomy followed by partial autotransplantation was effective in reducing PTH serum levels in patients with terminal kidney disease. The elevation of serum calcium during the suppression test was not able to inhibit the autograft gland secretion of PTH. The assessment of parathyroid graft function demonstrated an inability to respond to the stimulus of hypocalcemia induced by EDTA, although there was a partial recovery, in late postoperative period.

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Formation of stable thin films of mixed xyloglucan (XG) and alginate (ALG) onto Si/SiO2 wafers was achieved under pH 11.6, 50 mM CaCl2, and at 70 degrees C. XG-ALG films presented mean thickness of (16 +/- 2) nun and globules rich surface, as evidenced by means of ellipsometry and atomic force microscopy (AFM), respectively. The adsorption of two glucose/mannose-binding seed (Canavalia ensiformis and Dioclea altissima) lectins, coded here as ConA and DAlt, onto XG-ALG surfaces took place under pH 5. Under this condition both lectins present positive net charge. ConA and DAIt adsorbed irreversibly onto XG-ALG forming homogenous monolayers similar to(4 +/- 1)nm thick. Lectins adsorption was mainly driven by electrostatic interaction between lectins positively charged residues and carboxylated (negatively charged) ALG groups. Adhesion of four serotypes of dengue virus, DENV (1-4), particles to XG-ALG surfaces were observed by ellipsometry and AFM. The attachment of dengue particles onto XG-ALG films might be mediated by (i) H bonding between E protein (located at virus particle surface) polar residues and hydroxyl groups present on XG-ALG surfaces and (ii) electrostatic interaction between E protein positively charged residues and ALG carboxylic groups. DENV-4 serotype presented the weakest adsorption onto XG-ALG surfaces, indicating that E protein on DENV-4 surface presents net charge (amino acid sequence) different from E proteins of other serotypes. All four DENV particles serotypes adsorbed similarly onto lectin films adsorbed. Nevertheless, the addition of 0.005 mol/L of mannose prevented dengue particles from adsorbing onto lectin films. XG-ALG and lectin layers serve as potential materials for the development of diagnostic methods for dengue. (c) 2008 Elsevier B.V. All rights reserved.

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Objective To evaluate the influence of oral contraceptives (OCs) containing 20 mu mu g ethinylestradiol (EE) and 150 mu mu g gestodene (GEST) on the autonomic modulation of heart rate (HR) in women. Methods One-hundred and fifty-five women aged 24 +/-+/- 2 years were divided into four groups according to their physical activity and the use or not of an OC: active-OC, active-non-OC (NOC), sedentary-OC, and sedentary-NOC. The heart rate was registered in real time based on the electrocardiogram signal for 15 minutes, in the supine-position. The heart rate variability (HRV) was analysed using Shannon`s entropy (SE), conditional entropy (complexity index [CInd] and normalised CInd [NCI]), and symbolic analysis (0V%, 1V%, 2LV%, and 2ULV%). For statistical analysis the Kruskal-Wallis test with Dunn post hoc and the Wilcoxon test (p < 0.05 was considered significant) were applied. Results Treatment with this COC caused no significant changes in SE, CInd, NCI, or symbolic analysis in either active or sedentary groups. Active groups presented higher values for SE and 2ULV%, and lower values for 0V% when compared to sedentary groups (p < 0.05). Conclusion HRV patterns differed depending on life style; the non-linear method applied was highly reliable for identifying these changes. The use of OCs containing 20 mu mu g EE and 150 mu mu g GEST does not influence HR autonomic modulation.

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