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1.
T. Kullmer G. Kneissl T. Katova H. Kronenberger A. Urhausen W. Kindermann W. M?rz J. Meier-Sydow 《European journal of applied physiology and occupational physiology》1995,70(2):169-174
To clarify whether or not systolic and diastolic function of the human left ventricle (LV) were decreased during acute hypoxia, at rest and with exercise, 14 healthy male volunteers [age 25.9 (SD 3.0) years, height 182.9 (SD 7.1) cm, body mass 75.9 (SD 6.9)kg] were examined using M-mode and 2D-mode echocardiography to determine the systolic LV function as well as Doppler-echocardiography for the assessment of diastolic LV function on 2 separate test days. In random order, the subjects breathed either air on 1 day (N) or a gas mixture with reduced oxygen content on the other (H; oxygen fraction in inspired gas 0.14). Measurements on either day were made at rest, several times during incremental cycle exercise in a supine position (6-min increments of 50 W, maximal load 150 W) and in 6th min of recovery. Corresponding measurements during N and H were compared statistically. Arterial O2 tension (P
aO2) was normal on N-day. All subjects showed a marked acute hypoxia at rest [P
aO2, 54.5 (SD 4.6) mmHg], during exercise and recovery on H-day. The latter was associated with tachycardia compared to N-day. All echocardiographic measurements at rest were within the limits of normal values on both test days. Ejection time, end-systolic and end-diastolic left ventricular dimensions as well as the thickness of left posterior wall and of interventricular septum showed no statistically significant influence of H either at rest or during exercise. Stroke volume and cardiac output were always higher on H-day, which could be attributed to a slight reduction in end-systolic volume with unaffected end-diastolic volume as well as to increased heart rates. Among the indices of systolic LV function the fractions of thickening in the left ventricular posterior wall and interventricular septum showed no differences between H and N at rest or during exercise. However, fibre shortening, ejection fraction and mean circumferential fibre shortening were increased on H-day on all occasions. The mitral-valve-Doppler ratio, the index of diastolic LV function, was decreased with H at rest, showed a more pronounced reduction during exercise and was still lower in 6th min of recovery compared to N-day. It was concluded that with acute hypoxia of the severity applied in this study left ventricular systolic function in our healthy subjects showed a pronounced improvement and left ventricular diastolic function was reduced, both at rest and with exercise. 相似文献
2.
Tomas ML Eagan Esteban C Gabazza Corina D’Alessandro-Gabazza Paloma Gil-Bernabe Shinya Aoki Jon A Hardie Per S Bakke Peter D Wagner 《Respiratory research》2012,13(1):48
Background
Systemic inflammation may contribute to cachexia in patients with chronic obstructive pulmonary disease (COPD). In this longitudinal study we assessed the association between circulating C-reactive protein (CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 levels and subsequent loss of fat free mass and fat mass in more than 400 COPD patients over three years.Methods
The patients, aged 40–76, GOLD stage II-IV, were enrolled in 2006/07, and followed annually. Fat free mass and fat mass indexes (FFMI & FMI) were calculated using bioelectrical impedance, and CRP, TNF-α, IL-1ß, and IL-6 were measured using enzyme immunoassays. Associations with mean change in FFMI and FMI of the four inflammatory plasma markers, sex, age, smoking, FEV1, inhaled steroids, arterial hypoxemia, and Charlson comorbidity score were analyzed with linear mixed models.Results
At baseline, only CRP was significantly (but weakly) associated with FFMI (r = 0.18, p < 0.01) and FMI (r = 0.27, p < 0.01). Univariately, higher age, lower FEV1, and use of beta2-agonists were the only significant predictors of decline in FFMI, whereas smoking, hypoxemia, Charlson score, and use of inhaled steroids predicted increased loss in FMI. Multivariately, high levels of TNF-α (but not CRP, IL-1ß or IL-6) significantly predicted loss of FFMI, however only in patients with established cachexia at entry.Conclusion
This study does not support the hypothesis that systemic inflammation is the cause of accelerated loss of fat free mass in COPD patients, but suggests a role for TNF-α in already cachectic COPD patients. 相似文献3.
Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis 总被引:1,自引:0,他引:1 下载免费PDF全文
The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment. 相似文献
4.
Large, rapidly evolving intergenic spacers in the mitochondrial DNA of the salamander family Ambystomatidae (Amphibia: Caudata) 总被引:3,自引:2,他引:3
We report the presence, in the mitochondrial DNA (mtDNA) of all of the
sexual species of the salamander family Ambystomatidae, of a shared 240- bp
intergenic spacer between tRNAThr and tRNAPro. We place the intergenic
spacer in context by presenting the sequence of 1,746 bp of mtDNA from
Ambystoma tigrinum tigrinum, describe the nucleotide composition of the
intergenic spacer in all of the species of Ambystomatidae, and compare it
to other coding and noncoding regions of Ambystoma and several other
vertebrate mtDNAs. The nucleotide substitution rate of the intergenic
spacer is approximately three times faster than the substitution rate of
the control region, as shown by comparisons among six Ambystoma
macrodactylum sequences and eight members of the Ambystoma tigrinum
complex. We also found additional inserts within the intergenic spacers of
five species that varied from 87-444 bp in length. The presence of the
intergenic spacer in all sexual species of Ambystomatidae suggests that it
arose at least 20 MYA and has been a stable component of the ambystomatid
mtDNA ever since. As such, it represents one of the few examples of a large
and persistent intergenic spacer in the mtDNA of any vertebrate clade.
相似文献
5.
Eukaryotic cells coordinate chromosome duplication by the assembly of protein complexes at origins of DNA replication by sequential binding of member proteins of the origin recognition complex (ORC), CDC6, and minichromosome maintenance (MCM) proteins. These pre-replicative complexes (pre-RCs) are activated by cyclin-dependent kinases and DBF4/CDC7 kinase. Here, we carried out a comprehensive yeast two-hybrid screen to establish sequential interactions between two individual proteins of the mouse pre-RC that are probably required for the initiation of DNA replication. The studies revealed multiple interactions among ORC subunits and MCM proteins as well as interactions between individual ORC and MCM proteins. In particular CDC6 was found to bind strongly to ORC1 and ORC2, and to MCM7 proteins. DBF4 interacts with the subunits of ORC as well as with MCM proteins. It was also demonstrated that CDC7 binds to different ORC and MCM proteins. CDC45 interacts with ORC1 and ORC6, and weakly with MCM3, -6, and -7. The three subunits of the single-stranded DNA binding protein RPA show interactions with various ORC subunits as well as with several MCM proteins. The data obtained by yeast two-hybrid analysis were paradigmatically confirmed in synchronized murine FM3A cells by immunoprecipitation of the interacting partners. Some of the interactions were found to be cell-cycle-dependent; however, most of them were cell-cycle-independent. Altogether, 90 protein-protein interactions were detected in this study, 52 of them were found for the first time in any eukaryotic pre-RC. These data may help to understand the complex interplay of the components of the mouse pre-RC and should allow us to refine its structural architecture as well as its assembly in real time. 相似文献
6.
7.
The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased. Cell injury was partially overcome after repair in a salt-rich medium. Copyright 1998 Academic Press. 相似文献
8.
Danilo ML Prado Fabiana B Benatti Ana L de Sá-Pinto Ana P Hayashi Bruno Gualano Rosa MR Pereira Adriana ME Sallum Eloisa Bonfá Clovis A Silva Hamilton Roschel 《Arthritis research & therapy》2013,15(2):R46
Introduction
Exercise training has emerged as a promising therapeutic strategy to counteract physical dysfunction in adult systemic lupus erythematosus. However, no longitudinal studies have evaluated the effects of an exercise training program in childhood-onset systemic lupus erythematosus (C-SLE) patients. The objective was to evaluate the safety and the efficacy of a supervised aerobic training program in improving the cardiorespiratory capacity in C-SLE patients.Methods
Nineteen physically inactive C-SLE patients were randomly assigned into two groups: trained (TR, n = 10, supervised moderate-intensity aerobic exercise program) and non-trained (NT, n = 9). Gender-, body mass index (BMI)- and age-matched healthy children were recruited as controls (C, n = 10) for baseline (PRE) measurements only. C-SLE patients were assessed at PRE and after 12 weeks of training (POST). Main measurements included exercise tolerance and cardiorespiratory measurements in response to a maximal exercise (that is, peak VO2, chronotropic reserve (CR), and the heart rate recovery (ΔHRR) (that is, the difference between HR at peak exercise and at both the first (ΔHRR1) and second (ΔHRR2) minutes of recovery after exercise).Results
The C-SLE NT patients did not present changes in any of the cardiorespiratory parameters at POST (P > 0.05). In contrast, the exercise training program was effective in promoting significant increases in time-to-exhaustion (P = 0.01; ES = 1.07), peak speed (P = 0.01; ES = 1.08), peak VO2 (P = 0.04; ES = 0.86), CR (P = 0.06; ES = 0.83), and in ΔHRR1 and ΔHRR2 (P = 0.003; ES = 1.29 and P = 0.0008; ES = 1.36, respectively) in the C-SLE TR when compared with the NT group. Moreover, cardiorespiratory parameters were comparable between C-SLE TR patients and C subjects after the exercise training intervention, as evidenced by the ANOVA analysis (P > 0.05, TR vs. C). SLEDAI-2K scores remained stable throughout the study.Conclusion
A 3-month aerobic exercise training was safe and capable of ameliorating the cardiorespiratory capacity and the autonomic function in C-SLE patients.Trial registration
NCT01515163. 相似文献9.
Sabrina Kneissl Tobias Abel Anke Rasbach Julia Brynza Jürgen Schneider-Schaulies Christian J. Buchholz 《PloS one》2012,7(10)
Lentiviral vectors (LVs) are potent gene transfer vehicles frequently applied in research and recently also in clinical trials. Retargeting LV entry to cell types of interest is a key issue to improve gene transfer safety and efficacy. Recently, we have developed a targeting method for LVs by incorporating engineered measles virus (MV) glycoproteins, the hemagglutinin (H), responsible for receptor recognition, and the fusion protein into their envelope. The H protein displays a single-chain antibody (scFv) specific for the target receptor and is ablated for recognition of the MV receptors CD46 and SLAM by point mutations in its ectodomain. A potential hindrance to systemic administration in humans is pre-existing MV-specific immunity due to vaccination or natural infection. We compared transduction of targeting vectors and non-targeting vectors pseudotyped with MV glycoproteins unmodified in their ectodomains (MV-LV) in presence of α-MV antibody-positive human plasma. At plasma dilution 1∶160 MV-LV was almost completely neutralized, whereas targeting vectors showed relative transduction efficiencies from 60% to 90%. Furthermore, at plasma dilution 1∶80 an at least 4-times higher multiplicity of infection (MOI) of MV-LV had to be applied to obtain similar transduction efficiencies as with targeting vectors. Also when the vectors were normalized to their p24 values, targeting vectors showed partial protection against α-MV antibodies in human plasma. Furthermore, the monoclonal neutralizing antibody K71 with a putative epitope close to the receptor binding sites of H, did not neutralize the targeting vectors, but did neutralize MV-LV. The observed escape from neutralization may be due to the point mutations in the H ectodomain that might have destroyed antibody binding sites. Furthermore, scFv mediated cell entry via the target receptor may proceed in presence of α-MV antibodies interfering with entry via the natural MV receptors. These results are promising for in vivo applications of targeting vectors in humans. 相似文献
10.