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排序方式: 共有191条查询结果,搜索用时 15 毫秒
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FRANCISCO J. CHORRO JUAN GUERRERO JOAQUIN CANOVES MARCELINO MARTÍNEZ-SOBER LUIS MAINAR JUAN SANCHIS JAVIER CALPE ESTEBAN LLAVADOR JOSÉ ESPÍ VICENTE LÓPEZ-MERINO 《Pacing and clinical electrophysiology : PACE》1998,21(9):1716-1723
The characteristics of ventricular fibrillatory signals vary as a function of the time elapsed from the onset of arrhythmia and the maneuvers used to maintain coronary perfusion. The dominant frequency (FrD) of the power spectrum of ventricular fibrillation (VF) is known to decrease after interrupting coronary perfusion, though the corresponding recovery process upon reestablishing coronary flow has not been quantified to date. With the aim of investigating the recovery of the FrD during reperfusion after a brief ischemic, period, 11 isolated and perfused rabbit heart preparations were used to analyze the signals obtained with three unipolar epicardial electrodes (E1-E3) and a bipolar electrode immersed in the thermostatizfid organ bath (E4), following the electrical induction of VF. Recordings were made under conditions of maintained coronary perfusion (5 min), upon interrupting perfusion (15 mini, and after reperfusion (5 min), FrD was determined using Welch's method. The variations in FrD were quantified during both ischemia and reperfusion, based on an exponential model AFrD = A exp (-t/C). During ischemia ΔFrD is the difference between FrD and the minimum value, while t is the time elapsed from the interruption of coronary perfusion. During reperfusion ΔFrD is the difference between the maximum value and FrD, while t is the time elapsed from the restoration of perfusion, A is one of the constants of the model, and C is the time constant. FrD exhibited respective initial values of 16.20 ± 1.67, 16.03 ± 1.38, and 16.03 ± 1.80 Hz in the epicardial leads, and 15.09 ±1.07 Hz in the bipolar lead within the bath. No significant variations were observed during maintained coronary perfusion. The fit of the FrD variations to the model during ischemia and reperfusion proved significant in nine experiments. The mean time constants C obtained on fitting to the model during ischemia were as follows: El =294.4 ± 75.6, E2 = 225.7 ± 48.5, E3 = 327.4 ± 79.7, and E4 = 298.7 ± 43.9 seconds. The mean values of C obtained during reperfusion, and the significance of the differences with respect to the ischemic period were: El = 57.5 ± 8.4 (P ± 0.01), E2 = 64.5 ± 11.2 (P0.01), E3 = 80.7 ± 13.3 (P < 0.01), and E4 = 74.9 ± 13.6 (P < 0.0001). The time course variations of the FrD of the VF power spectrum fit an exponential model during ischemia and reperfusion. The time constants of the model during reperfusion after a brief ischemic period are significantly shorter than those obtained during ischemia. 相似文献
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As a part of a Research program aimed at studying synthesis and conformation of small ring peptides, the cyclization of diastereoisomeric N-phenylacetyl-seryl-propyl-proline tripeptides has been examined. Two 10- membered peptide lactones, and , have been isolated by treating the corresponding linear p-nitrophenyl esters with DBU in dry benzene. In these two compounds the serine lactone fragment (a common structural feature of several bioactive cyclodepsipeptides) is inserted into a highly strained small ring system. The conformation in the crystal of 5a and 5b has been studied by X-ray analysis. Both the 10-membered rings of 5a and 5b adopt an overall cis-cis-trans conformation in which the lactone junction is trans. The deviations from planarity of the peptide units vary from Δω= 30° for the DSer—Pro bond in 5b to Ao= 5-6° for the DSer-PrO bond in 5a and PrO—DPrO bond in 5b . The skeletal atoms of 5b , containing the PrO-DPrO sequence, are related by a pseudo-symmetry mirror plane passing through the Pro carbonyl and the opposite DSer CβH2 group. In both the molecules the exocyclic amide bond adopts an extended conformation with respect to the DSer-Pro ring junction; this arrangement gives rise to a C5-type ring structure which is well evidenced in the case of 5a . 相似文献
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Wireless Ultrasound Guidance for Femoral Venous Cannulation in Electrophysiology: Impact on Safety,Efficacy, and Procedural Delay
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DANIEL RODRÍGUEZ MUÑOZ M.D. EDUARDO FRANCO DÍEZ M.D. JAVIER MORENO M.D. Ph.D. GIUSEPPE LUMIA M.D. ALEJANDRA CARBONELL SAN ROMÁN M.D. TERESA SEGURA DE LA CAL M.D. ROBERTO MATÍA FRANCÉS M.D. Ph.D. ANTONIO HERNÁNDEZ MADRID M.D. Ph.D. JOSÉ LUIS ZAMORANO GÓMEZ M.D. Ph.D. 《Pacing and clinical electrophysiology : PACE》2015,38(9):1058-1065
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Unexpected Immunoresponse to Gal and APA Antigens in Diabetic Type 1 Patients Receiving Neonatal Pig Islets After 6 Years 总被引:1,自引:0,他引:1
Valdés-González RA Dorantes LM Garibay GN Bracho-Blanchet E Dávila-Pérez R Terán L Ormsby CE Ayala-Sumuano JT Copeman L White DJ 《Journal of clinical immunology》2007,27(3):266-274
Cotransplantation of porcine islets and Sertoli cells into preimplanted subcutaneous devices improve metabolic control in
type 1 diabetic patients, and survive grafted for more than 4 years. We report here, further assessment of the endocrine and
porcine nature of the surviving cells and the immune responses elicited toward Gal α(1,3)-Gal β(1,4)-GlcNAc (Gal) antigen
in patients who received a second and third transplants. No immunosuppressive drugs were administered. We were able to immunostain
insulin- and glucagon-positive cells in all biopsies of patients and Sertoli cell markers in 60.9% of biopsies. Additionally,
all biopsies tested, amplified the porcine COII gene. Patients demonstrated an increase in antipig antibodies in response
to the first transplant with a decreasing response toward the second and third transplants. In all transplants, the IgG levels
promptly returned to basal values after 3–4 months. The long-term survival of porcine cells and the reduced humoral immune
response to multiple transplants indicate a form of tolerance. We have not been able to find CD25-positive cells, indicating
that it is probably an immune accommodation of the graft. 相似文献
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Primary Immunodeficiency Diseases in Latin America: The Second Report of the LAGID Registry 总被引:4,自引:4,他引:0
Leiva LE Zelazco M Oleastro M Carneiro-Sampaio M Condino-Neto A Costa-Carvalho BT Grumach AS Quezada A Patiño P Franco JL Porras O Rodríguez FJ Espinosa-Rosales FJ Espinosa-Padilla SE Almillategui D Martínez C Tafur JR Valentín M Benarroch L Barroso R Sorensen RU;Latin American Group for Primary Immunodeficiency Diseases 《Journal of clinical immunology》2007,27(1):101-108
This is the second report on the continuing efforts of LAGID to increase the recognition and registration of patients with
primary immunodeficiency diseases in 12 Latin American countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Honduras,
Mexico, Panama, Paraguay, Peru, Uruguay, and Venezuela. This report reveals that from a total of 3321 patients registered,
the most common form of primary immunodeficiency disease was predominantly antibody deficiency (53.2%) with IgA deficiency
reported as the most frequent phenotype. This category was followed by 22.6% other well-defined ID syndromes, 9.5% combined
T- and B-cell inmunodeficiency, 8.6% phagocytic disorders, 3.3% diseases of immune dysregulation, and 2.8% complement deficiencies.
All countries that participated in the first publication in 1998 reported an increase in registered primary immunodeficiency
cases, ranging between 10 and 80%. A comparison of the estimated minimal incidence of X-linked agammaglobulinemia, chronic
granulomatous disease, and severe combined immunodeficiency between the first report and the present one shows an increase
in the reporting of these diseases in all countries. In this report, the estimated minimal incidence of chronic granulomatous
disease was between 0.72 and 1.26 cases per 100,000 births in Argentina, Chile, Costa Rica, and Uruguay and the incidence
of severe combined immunodeficiency was 1.28 and 3.79 per 100,000 births in Chile and Costa Rica, respectively. However, these
diseases are underreported in other participating countries. In addition to a better diagnosis of primary immunodeficiency
diseases, more work on improving the registration of patients by each participating country and by countries that have not
yet joined LAGID is still needed.
Latin American Group for Primary Immunodeficiency Diseases 相似文献
10.
Application of the fractionator and vertical slices to estimate total capillary length in skeletal muscle 总被引:1,自引:0,他引:1
EMILIO ARTACHO-PÉRULA RAFAEL ROLDÁN-VILLALOBOS LUIS M. CRUZ-ORIVE 《Journal of anatomy》1999,195(3):429-437
A new stereological method is proposed which combines vertical slice projections with the fractionator to estimate the total capillary length in a skeletal muscle. The method was demonstrated on the soleus muscle of a Wistar rat. The implementation required capillary highlighting, tissue sampling, and data acquisition in the form of intersection counts between capillary projections and cycloid test lines. The capillaries were demonstrated using vascular perfusion (with gelatine) of the hind leg of the rat. The sampling procedure followed the fractionator design, namely a multistage systematic sampling design with a known sampling fraction at each stage. To make the design unbiased, vertical slices were used; for efficiency, the vertical axis was chosen parallel to the main axis of the muscle. As prescribed to avoid bias, the cycloid test lines were superimposed on the slice projections, viewed under the light microscope, with their minor axes normal to the vertical axis. The estimation precision was compared for different sampling and subsampling fractions. The proposed method was globally highly efficient, unbiased, and easy to implement. 相似文献