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41.
Pendergast D Zamparo P di Prampero PE Capelli C Cerretelli P Termin A Craig A Bushnell D Paschke D Mollendorf J 《European journal of applied physiology》2003,90(3-4):377-386
In this paper a complete energy balance for water locomotion is attempted with the aim of comparing different modes of transport in the aquatic environment (swimming underwater with SCUBA diving equipment, swimming at the surface: leg kicking and front crawl, kayaking and rowing). On the basis of the values of metabolic power (Ė), of the power needed to overcome water resistance (d) and of propelling efficiency (P=d/tot, where tot is the total mechanical power) as reported in the literature for each of these forms of locomotion, the energy cost per unit distance (C=Ė/v, where v is the velocity), the drag (performance) efficiency (d=d/Ė) and the overall efficiency (o=tot/Ė=d/P) were calculated. As previously found for human locomotion on land, for a given metabolic power (e.g. 0.5 kW=1.43 l·min–1 O2) the decrease in C (from 0.88 kJ·m–1 in SCUBA diving to 0.22 kJ·m–1 in rowing) is associated with an increase in the speed of locomotion (from 0.6 m·s–1 in SCUBA diving to 2.4 m·s–1 in rowing). At variance with locomotion on land, however, the decrease in C is associated with an increase, rather than a decrease, of the total mechanical work per unit distance (Wtot, kJ·m–1). This is made possible by the increase of the overall efficiency of locomotion (o=tot/Ė=Wtot/C) from the slow speeds (and loads) of swimming to the high speeds (and loads) attainable with hulls and boats (from 0.10 in SCUBA diving to 0.29 in rowing). 相似文献
42.
Capelli C Cautero M di Prampero PE 《Pflügers Archiv : European journal of physiology》2001,441(4):566-577
Alveolar gas transfer over a given breath (i) was determined in ten subjects at rest and during steady-state cycling at 60, 90 or 120 W as the sum of volume of gas transferred at the mouth plus the changes of the alveolar gas stores. This is given by the gas fraction (FA) change at constant volume plus the volume change (deltaVAi) at constant fraction i.e. VAi-1(FAi-FAi-1)+FAi x deltaVAi, where VAi-1 is the end-expiratory volume at the beginning of the breath. These quantities, except for VAi-1, can be measured on a single-breath (breath-by-breath) basis and VAi-1 set equal to the subject's functional residual capacity (FRC, Auchincloss model). Alternatively, the respiratory cycle can be defined as the interval elapsing between two equal expiratory gas fractions in two successive breaths (Gr?nlund model G). In this case, Ft1 = Ft2 and thus the term VAi-1 (FAi-FAi-1) vanishes. In the present study, average alveolar O2 uptake (VO2,A) and CO2 output (VCO2,A) were equal in both approaches whereby the mean signal-to-noise ratio (S/N) was 40% larger in G. Other approaches yield steady state S/N values equal to that obtained in G, although they are based on the questionable assumption that the inter-breath variability of alveolar gas transfer is minimal. It is concluded that the only promising approach for assessing "true" single-breath alveolar gas transfer is that originally proposed by Gr?nlund. 相似文献
43.
di Gioia CR Ciallella C d'Amati G Parroni E Nardone AM Gallo P 《Archives of pathology & laboratory medicine》2003,127(9):e367-e370
An infant with normal facies and none of the extracardiac anomalies usually associated with Williams syndrome presented at birth with an echocardiographic pattern of supravalvular pulmonary stenosis and displastic pulmonary valve. A clinical reappraisal was planned at 3 months of age, but the girl died suddenly at home at 2 months of age. At autopsy, both ventricles were hypertrophic, and the valves showed mild dysplasia. The walls of the great arteries were thick, with a "washed leather" consistency, but there was no gross evidence of discrete stenosis. The histologic mosaic appearance of the media of the great arteries, due to elastosis and extreme disarray of the elastic lamellae, prompted a postmortem diagnosis of supravalvar aortic stenosis and suggested a diagnosis of Williams syndrome, which was subsequently confirmed by fluorescence in situ hybridization. Pediatricians and pathologists should be alerted that Williams syndrome in the newborn may present as an isolated supravalvular pulmonary stenosis, whereas supravalvular aortic stenosis becomes clinically significant only a few months later. 相似文献
44.
A 0.31-kilobase fragment of SV40 DNA containing the early promoter of this virus was isolated. The pX1 plasmid containing the herpesvirus thymidine kinase gene (TK) was cleaved with BglII and SalI to remove the TK promoter. The Sv40 DNA fragment was mixed with the TK gene without its promoter and blunt-end ligated after treatment with S1 nuclease. The newly engineered plasmid was used for the transformation of TK-deficient LtA cells to TK+ phenotype. Blot hybridization experiments show that the plasmid is integrated into high-molecular-weight DNA in both of the transformed colonies that we have studied. Also the mRNA in these cells is a hybrid molecule containing both TK and SV40 sequences. 相似文献
45.
The long pentraxin PTX3 up-regulates tissue factor in activated monocytes: another link between inflammation and clotting activation 总被引:4,自引:0,他引:4
Napoleone E di Santo A Peri G Mantovani A de Gaetano G Donati MB Lorenzet R 《Journal of leukocyte biology》2004,76(1):203-209
Pentraxin-3 (PTX3), an acute-phase protein that belongs to the family of the PTXs, is found elevated in septic shock and increased in patients with acute myocardial infarction. As tissue factor (TF) plays a key role in thrombosis and inflammation associated with atherosclerosis and as we have recently reported that PTX3 increases TF synthesis in endothelial cells, we tested whether PTX3 could modulate TF expression in monocytes. Monocytes from peripheral blood of healthy donors were incubated with highly purified PTX3 with or without lipopolysaccharide (LPS). Cells were then disrupted, and procoagulant activity was assessed by a one-stage clotting time. PTX3 enhanced TF activity and antigen from LPS-stimulated monocytes in a dose-dependent way. The effect was specific, as other PTXs, such as C-reactive protein and serum amyloid P component, were ineffective. Moreover, the increase in activity was specific for LPS, as in the presence of other TF-inducing agents such as interleukin-1beta and tumor necrosis factor alpha, PTX3 was not effective. The increase in TF activity requires mRNA synthesis, as assessed by polymerase chain reaction. The mechanism by which PTX3 modulates TF synthesis resides in an enhanced IkappaB, alpha phosphorylation and degradation and increased migration of the transacting factor c-Rel/p65 into the nucleus, as determined by Western blot and electro-mobility shift assay. These results show that PTX3 is an enhancer of the expression of TF by mononuclear cells. In the area of vascular injury, during the inflammatory response, cell-mediated fibrin deposition takes place. PTX3 increases TF expression, thus potentially playing a role in thrombogenesis and wound healing. 相似文献
46.
A significant problem in the immunoassay of angiotensin II is the cross-reactivity of most available antisera with the peptide's metabolic products, (des-Asp1)-angiotensin II and (des-Asp1.Arg2)-angiotensin II. In order to attempt to generate antisera of greater selectivity, a variety of conjugates between angiotensin II or derivative peptides and carrier proteins were examined as immunogens with the aim of generating antisera that would selectively identify the amino terminal region of the peptide. Selectivity for the amino terminus was achieved by either (1) immunization with N-acetylated angiotensin II-amide which had been coupled to rabbit serum albumin by its carboxy terminus, or (2) immunization with angiotensin-(1-7)-heptapeptide which was randomly coupled to thyroglobulin. The antisera produced with the N-acetylated immunogen cross-reacted with the unacetylated ligand (Asn1-Val5)-angiotensin, but did not recognize the human hormone (Asp1,Ile5)-angiotensin. Carboxy-terminal coupling of angiotensin without N-acetylation did not induce selectivity for the amino terminus, nor did a conjugate which was linked to the carrier protein via a diazo bond to His6 of the peptide. These findings may be explained by the fact that N-acetylated angiotensin II resists degradation by amino peptidases and thus retains its structure in the immunogen and by the fact that the (1-7)-heptapeptide has lost the immunodominant carboxy-terminal epitope, thus emphasizing the desired amino terminal determinant. 相似文献
47.
Antal Ngrdi 《The American journal of pathology》1998,153(1):1-4
48.
Angela Pucci MD Ezio David MD Michele di Summa MD Enrico Donegani MD Valeria Ghisetti MD Mario Morea MD Franco Mollo MD 《Cardiovascular pathology》1993,2(4):259-261
Dissecting aneurysms of coronary arteries are a rare finding and have never been reported in a cardiac allograft. We found two spontaneous dissecting aneurysms on the middle third of both the left anterior descending and the right coronary arteries in a female cardiac transplantation recipient. She died 43 days after cardiac transplantation after developing human cytomegalovirus pneumonia and pancreatitis. Dissecting coronary aneurysms, microfoci of subendocardial coagulative necrosis, and area of subepicardial dystrophic calcifications were discovered at necropsy examination. 相似文献
49.
Carlo Capelli Guglielmo Antonutto Paola Zamparo Massimo Girardis Pietro Enrico di Prampero 《European journal of applied physiology》1993,66(3):189-195
Summary The mechanical power (Wtot, W·kg–1) developed during ten revolutions of all-out periods of cycle ergometer exercise (4–9 s) was measured every 5–6 min in six subjects from rest or from a baseline of constant aerobic exercise [50%–80% of maximal oxygen uptake (VO2max)] of 20–40 min duration. The oxygen uptake [VO2 (W·kg–1, 1 ml O2 = 20.9 J)] and venous blood lactate concentration ([la]b, mM) were also measured every 15 s and 2 min, respectively. During the first all-out period, Wtot decreased linearly with the intensity of the priming exercise (Wtot = 11.9–0.25·VO2). After the first all-out period (i greater than 5–6 min), and if the exercise intensity was less than 60% VO2max, Wtot, VO2 and [la]b remained constant until the end of the exercise. For exercise intensities greater than 60% VO2max, VO2 and [la]b showed continuous upward drifts and Wtot continued decreasing. Under these conditions, the rate of decrease of Wtot was linearly related to the rate of increase of V [(d Wtot/dt) (W·kg–1·s–1) = 5.0·10–5 –0.20·(d VO2/dt) (W·kg–1·s–1)] and this was linearly related to the rate of increase of [la]b [(d VO2/dt) (W·kg–1·s–1) = 2.310–4 + 5.910–5·(d [la]b/dt) (mM·s–1)]. These findings would suggest that the decrease of Wtot during the first all-out period was due to the decay of phosphocreatine concentration in the exercising muscles occurring at the onset of exercise and the slow drifts of VO2 (upwards) and of Wtot (downwards) during intense exercise at constant Wtot could be attributed to the continuous accumulation of lactate in the blood (and in the working muscles). 相似文献
50.
Giacchino R di Martino L Losurdo G Pisanti A 《Le infezioni in medicina : rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive》2003,11(2):86-92
From the second half of the eighties, the cases of tuberculosis (TBC) in Italy have been constantly increasing. The increase in TBC cases in developed countries is related to different factors, including HIV epidemic and increased number of immigrants from countries with high TBC incidence and important socio-economic problems. Compared with adults few children with TBC were homeless or coinfected with HIV, nonetheless the children lived frequently in low socioeconomic status and consequently high risk of being uninsured and with adults at risk for tuberculosis (immediate relative, household members, or recently immigrated). An epidemiologic study was carried out, in order to evaluate the impact of TBC infection in immigrant children. From January 2001 to December 2002, Mantoux test (5 IU) was performed in immigrant children hospitalized or followed in two children hospitals. They included 228 children: mean age 4 years (range 1 month to 15 years). The patients came from: South America (44%) (especially from Ecuador), from Africa (20%), from Eastern Europe (19%), (especially from Middle East and North Africa), from Far East (17%). In 30 cases (13,2%) Mantoux test was positive. Among these latter, 21 presented latent infection, whereas another 9 had tuberculous disease with pulmonary localization and one of them associated with cervical adenopathy. In the study period, among all children (4426) admitted the two Units, the prevalence of tuberculous disease was 2,5% in immigrant children compared 0.2% in native children. Accurate epidemiologic monitoring, further clinical studies aimed at highlighting TBC peculiar aspects in children, and adequate therapy can lead to TBC control in the immigrant children. 相似文献