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排序方式: 共有2216条查询结果,搜索用时 15 毫秒
1.
Stavros Bekas 《Teaching and learning in medicine》2015,27(1):4-11
Phenomenon: The central role of clinical leadership in achieving the vision of quality and productivity could be attained by investing in its development in postgraduate medical education. Approach: A critical review of selected literature is presented. Findings: The author identifies some of the main theoretical constructs related to leadership; the pedagogical underpinning of medical leadership programs; their learning objectives; and the mixture of methods, individual and collective, to achieve them. Insights: How to best develop leadership through medical education remains an open debate. Experiential learning, reflective practice, action learning, and mentoring could provide the foundations of leadership development. Application of the aforementioned should be cautious due to limitations of the concept of leadership as currently promoted and lack of robust evaluation methodologies. 相似文献
2.
Elena Christoforou Ioannis Papassotiriou Christophille Skarmoutsou Stavros Doudounakis Alexandra Stamoulakatou Emmanuel Kanavakis 《Journal of cystic fibrosis》2005,4(3):151-156
BACKGROUND: Chronic pulmonary disease and progressive tissue hypoxia are major causes of morbidity and mortality in cystic fibrosis (CF). Normally the body adapts to tissue hypoxia by increasing the red cell mass and decreasing the Hb-O(2) affinity. These adaptations are commonly observed in patients with cyanotic heart disease and individuals living at high altitude. However, patients with CF not only have an impaired erythroid response to hypoxia, but also are frequently anaemic. METHODS: In order to evaluate erythroid marrow activity and tissue oxygenation in 37 patients with CF we measured: the haematological and blood chemistry parameters; including red cell indices, ferritin, erythropoietin (Epo) and soluble transferrin receptors (sTfR) levels; arterial blood gases, P(50) and oxygen release to the tissues (O(2)(R)) and the 2,3-BPG levels. RESULTS: The main results showed that a) patients with CF have a mild degree of tissue hypoxia which is expressed by the moderately decreased of P(50) and O(2)(R) values and the relative increase of Epo level, b) 2,3-BPG synthesis in patients with CF is normal and c) sTfR levels are significantly increased (3-fold normal) in patients with CF compared to normal controls. CONCLUSIONS: The above observations indicate that erythroid marrow activity in patients with CF is increased. 相似文献
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Robert L Jilka Robert S Weinstein A Michael Parfitt Stavros C Manolagas 《Journal of bone and mineral research》2007,22(10):1492-1501
Since the initial demonstration of the phenomenon in murine and human bone sections approximately 10 yr ago, appreciation of the biologic significance of osteoblast apoptosis has contributed greatly not only to understanding the regulation of osteoblast number during physiologic bone remodeling, but also the pathogenesis of metabolic bone diseases and the pharmacology of some of the drugs used for their treatment. It is now appreciated that all major regulators of bone metabolism including bone morphogenetic proteins (BMPs), Wnts, other growth factors and cytokines, integrins, estrogens, androgens, glucocorticoids, PTH and PTH-related protein (PTHrP), immobilization, and the oxidative stress associated with aging contribute to the regulation of osteoblast and osteocyte life span by modulating apoptosis. Moreover, osteocyte apoptosis has emerged as an important regulator of remodeling on the bone surface and a critical determinant of bone strength, independently of bone mass. The detection of apoptotic osteoblasts in bone sections remains challenging because apoptosis represents only a tiny fraction of the life span of osteoblasts, not unlike a 6-mo-long terminal illness in the life of a 75-yr-old human. Importantly, the phenomenon is 50 times less common in human bone biopsies because human osteoblasts live longer and are fewer in number. Be that as it may, well-controlled assays of apoptosis can yield accurate and reproducible estimates of the prevalence of the event, particularly in rodents where there is an abundance of osteoblasts for inspection. In this perspective, we focus on the biological significance of the phenomenon for understanding basic bone biology and the pathogenesis and treatment of metabolic bone diseases and discuss limitations of existing techniques for quantifying osteoblast apoptosis in human biopsies and their methodologic pitfalls. 相似文献
5.
Frangiskos I Parthenakis Alexandros P Patrianakos Panagiotis G Tzerakis Despina M Kambouraki Stavros I Chrysostomakis Panos E Vardas 《Journal of the American Society of Echocardiography》2004,17(2):139-145
BACKGROUND: Early color M-mode Doppler flow propagation (Ep) through the left ventricle (LV) has been proposed as a useful noninvasive index for assessing LV relaxation, whereas data concerning late velocity propagation (Ap) is lacking. METHODS: We studied 51 patients with delayed relaxation (group I) and 50 with pseudonormal filling pattern (group II). Another 51 aged-matched healthy persons served as the control group. RESULTS: Patients showed increased left atrial dimensions, atrial wave of the pulmonary vein flow, and Ap, and reduced LV ejection fraction, Ep, and Ep/Ap ratio compared with the control group. Patients in group II revealed increased left atrial dimensions (P =.001), atrial wave of the pulmonary vein flow (P <.001), and Ep/Ap ratio (P <.001), and reduced LV ejection fraction and Ap (P <.001) compared with group I. Regression analysis showed that the strongest independent variable distinguishing normal from pseudonormal filling pattern was the Ep/Ap ratio. CONCLUSION: Ap evaluation offers a new diagnostic diastolic index, especially in the field of the pseudonormal pattern where the separation from normal is difficult. 相似文献
6.
Tiniakos D Anagnostou V Stavrakis S Karandrea D Agapitos E Kittas C 《Anatomy and embryology》2004,209(1):41-47
We aimed to define, for the first time, the ontogeny of intrarenal innervation and to assess the distribution and nature of parenchymal nerves in the human fetal kidney. Our material consisted of routinely-processed renal tissue sections from 17 human fetuses, six of 20–24 gestational weeks (gw) and 11 of 25–40 gw, and three adults. We used immunohistochemistry with antibodies to the pan-neural markers neuron-specific enolase (NSE), neurofilaments (NF), PGP9.5, S100, and the adrenergic marker tyrosine hydroxylase (TH). NSE-, NF-, S100-, and PGP9.5-positive nerves, associated with arterial and venous vasculature, were identified in the renal cortex from 20 gw onwards, and their density appeared to increase with gestation, reaching adult levels at 28 gw. Most of the intrarenal nerves were TH-positive. Nerve fibers extended from the corticomedullary region to the outer cortex, reaching the renal capsule in the 3rd trimester. In detail, NSE-, NF-, S100-, PGP9.5-, and TH-immunoreactive fibers were observed in close apposition to the renal artery and its branches, occasionally reaching the afferent and efferent arteriole (3rd trimester). Nerve fibers were detected in close apposition to the juxtaglomerular apparatus in the 2nd and 3rd trimesters. In the renal medulla, NSE-, PGP9.5-, S100-, and TH-positive nerve fibers were detected close to tubular cells as early as 20 gw. However, their density gradually decreased during the 3rd trimester, and they were not observed in the medulla of the adult kidney. In conclusion, the human fetal kidney appears richly innervated during the 2nd and 3rd trimesters. There is a progressive increase in the density of parenchymal nerve fibers towards term from the corticomedullary region to the cortex. Most intrarenal nerves are adrenergic and have a predominant perivascular distribution, implying that renal innervation plays an important functional role during intrauterine life. 相似文献
7.
Aboudola S Kotloff KL Kyne L Warny M Kelly EC Sougioultzis S Giannasca PJ Monath TP Kelly CP 《Infection and immunity》2003,71(3):1608-1610
There is a strong association between serum antibody responses to toxin A and protection against Clostridium difficile diarrhea. A parenteral C. difficile toxoid vaccine induced very-high-level responses to anti-toxin A immunoglobulin G (IgG) in the sera of healthy volunteers. After vaccination, the concentrations of anti-toxin A IgG in the sera of all 30 recipients exceeded the concentrations that were associated with protection in previous clinical studies. Furthermore, the median concentration of serum anti-toxin A IgG in the test group was 50-fold higher than the previous threshold. These findings support the feasibility of using a vaccine to protect high-risk individuals against C. difficile-associated diarrhea and colitis. 相似文献
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Inhibiting complement anaphlytoxin C5a during sepsis may prevent sepsis mortality. Although human anti-C5 antibodies exist, their therapeutic use in microbial sepsis has been avoided because of the hypothesis that inhibiting C5b will prevent formation of the bactericidal membrane attack complex (MAC) and worsen clinical outcome. We wished to test the hypothesis that inhibition of C5 would improve outcomes in sepsis. Sepsis was induced in rats by laparotomy and cecal ligation and puncture (CLP) by an IACUC-approved protocol. Sham animals underwent laparotomy without CLP. Following CLP rats were randomized to receive a single IV dose of purified IgG ant-C5 antibody (Ab) or control IgG Ab. Anti-C5 Ab treated rats (n = 20) had significantly lower mortality vs. controls (n = 21), 20% vs. 52% (P = 0.019, log-rank). Analysis of bacterial load by culture of spleen and liver homogenates showed a reduction in colony forming units in anti-C5 Ab treated rats vs. control IgG (P = 0.003 and 0.009, respectively). Anti-C5 treatment reduced lung injury as measured by total MPO content of lung tissue (P = 0.024). Finally, rats genetically deficient in C6 production, unable to form MAC but capable of producing C5a and C5b, were protected from CLP-induced sepsis mortality. Our results show that in anti-C5 antibody therapy prevents CLP sepsis-induced mortality and improves lung injury. Inhibition of the complement MAC does not increase bacterial load or mortality, therefore, the use of anti-C5 therapy may be beneficial rather than detrimental in sepsis. 相似文献
10.
D'Adamo P Welzl H Papadimitriou S Raffaele di Barletta M Tiveron C Tatangelo L Pozzi L Chapman PF Knevett SG Ramsay MF Valtorta F Leoni C Menegon A Wolfer DP Lipp HP Toniolo D 《Human molecular genetics》2002,11(21):2567-2580
Non-specific mental retardation (NSMR) is a common human disorder characterized by mental handicap as the only clinical symptom. Among the recently identified MR genes is GDI1, which encodes alpha Gdi, one of the proteins controlling the activity of the small GTPases of the Rab family in vesicle fusion and intracellular trafficking. We report the cognitive and behavioral characterization of mice carrying a deletion of Gdi1. The Gdi1-deficient mice are fertile and anatomically normal. They appear normal also in many tasks to assess spatial and episodic memory and emotional behavior. Gdi1-deficient mice are impaired in tasks requiring formation of short-term temporal associations, suggesting a defect in short-term memory. In addition, they show lowered aggression and altered social behavior. In mice, as in humans, lack of Gdi1 spares most central nervous system functions and preferentially impairs only a few forebrain functions required to form temporal associations. The general similarity to human mental retardation is striking, and suggests that the Gdi1 mutants may provide insights into the human defect and into the molecular mechanisms important for development of cognitive functions. 相似文献