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91.
Voltage-clamp experiments have been performed on ovulated Xenopus laevis oocytes. Two kinds of oocytes were studied: mature oocytes presenting the white spot due to germinal vesicle breakdown (GVBD) were found to be essentially unexcitable; oocytes without the white spot appeared to possess ionic channels which open transiently on hyperpolarization. The current is carried by chloride ions and, in Holtfreter's solution, has a reversal potential at approximately - 15 mV.  相似文献   
92.
Physical activity increases the work load of the heart. The adjustments of the heart depend on the quality and quantity of the work performed. These adjustments concern the function and the morphology of the cardiovascular system. It is important to underline that these adjustments are not permanent and can disappear when physical activity is stopped. In young subjects the risks are very few while the benefits may be shown on a better and more armonic body structure. In the elderly the benefits can be achieved with a lesser cost for submaximal activities, but the risks are of course more frequent due the possible onset of cardiovascular disease. It is important to correctly recognize the limits whitin which the physical activity can be allowed because beneficial. Echocardiography has given an important contribution to evaluate the morpho-functional adaptions of the athlete's heart. Similarly, it has proven useful in the detection of pathological cardiovascular modifications, asymptomatic or pausymptomatic, that do not allow certification to practise sport at agonistic levels.  相似文献   
93.
A new route for the synthesis of high glass transition temperature, thermally stable polymer foams has been developed, using compositionally asymmetric microphase-separated block copolymers where the minor component (poly(propylene oxide)) is thermally labile and the major component (polyimide) is thermally stable. The minor component decomposes to low molecular weight species upon heating, and the decomposition products diffuse out of the film, leaving behind pores embedded in a matrix of the thermally stable component. In this study, the polyimide block was crosslinked with ethynyl functionalities to obtain a stable porous structure. The decomposition of the propylene oxide in the block copolymer was studied by thermogravimetric, dynamic mechanical and thermomechanical analyses. Mild conditions were required to avoid rapid depolymerization of the propylene oxide and plasticization of the polyimide matrix. The foams showed pore sizes with diameters up to a micrometer in size as well as the expected reduction in the mass density.  相似文献   
94.
Summary Basing our study on serial cuts and dissections, we have analysed the various techniques for puncture and injection in the region of the shoulder, the scapulohumeral and acromioclavicular joints, the subdeltoid bursa, the peri-articular muscles and tendons and the suprascapular nerve.
Bases anatomiques des ponctions et injections de l'épaule
Résumé A partir de coupes sériées et de dissections les auteurs étudient les différentes techniques de ponctions et injections pratiquées au niveau de la région de l'épaule, articulations scapulo-humérale et acromio-claviculaire, bourse sous-deltoïdienne, tendons des muscles péri-articulaires et nerf sus-scapulaire.
  相似文献   
95.
One hundred and fifty-two children affected by respiratory syndromes, probably due to allergy, underwent skin testing to a range of extracts including several different species of mites. The incidence of positive reactions to different allergens was studied in two groups: below and over 4 years, each including both outpatients and inpatients. The aetiologic role of mites has been evaluated considering positive skin tests to single species between and within families.  相似文献   
96.
A longitudinal epidemiological respiratory study has been started in the North of Italy to investigate the natural history of obstructive airways disease and the long-term effect of SO2 exposure. The first cross-sectional study was completed in this unpolluted area before the activation of a thermoelectric power plant (500 tons of SO2 produced daily). Follow-up surveys are planned after pollution emission starts for a period of ten years. A sample (n = 3289) representative of the general population was drawn from the villages of the area according to the different risks of pollution exposure. Subjects completed questionnaires and performed lung function tests, including forced expiratory (FVC) manoeuvres. For 801 'normal' subjects, prediction equations have been derived in age/sex groups for slow vital capacity (VC) and variables from the FVC manoeuvre. Comparisons with predictions of other studies are reported. Differences among FVC predictions were found, indicating that the use of different criteria for determination of the FVC manoeuvre end-point can affect results. In 'normals' VC was higher than FVC in older subjects. The difference between VC and FVC may be hypothesized as an epidemiological indication of the ageing effect on the mechanical properties of the ventilatory system.  相似文献   
97.
98.
S Di Cesare  F Poccia  A Mastino    V Colizzi 《Immunology》1992,76(2):341-343
The expression of heat-shock proteins (HSP) of the 72,000 MW family by Daudi and H9 lymphoma cells has been investigated by flow cytometry. It has been found that both heat-stressed and chronically human immunodeficiency virus (HIV)-infected lymphomas show an increased expression of heat-shock proteins (HSP). Moreover, murine monoclonal antibody (mAb) against 72,000 MW HSP was able to mediate antibody-dependent cellular cytotoxicity (ADCC) using peripheral blood lymphocytes (PBL) as effector cells. All target cells used in these experiments were efficiently lysed in the presence of anti-HSP antibody suggesting a role of membrane HSP in the elimination of stressed or infected cells.  相似文献   
99.
100.
We report a case of osteomyelitis caused by Enterobacter cancerogenus resistant to aminopenicillins in a 56-year-old male who had a motorcycle accident and suffered from multiple bone fractures with abundant environmental exposure. E. cancerogenus has rarely been associated with human infections, and its clinical significance remains unclear.  相似文献   
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