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991.
992.
Hník P. Holas M. Krekule I. Kříž N. Mejsnar J. Smieško V. Ujec E. Vyskočil F. 《Pflügers Archiv : European journal of physiology》1976,362(1):85-94
Using liquid ion-exchanger semimicroelectrodes with a side pore, we measured changes of extracellular potassium concentration (Ke
+) in adult rabbit and cat gastrocnemius muscles and in venous effluent blood flowing from the cat gastrocnemius muscle during various bouts of activity induced by sciatic nerve stimulation.
相似文献
1. | Isometric tetanic contractions (at 50 Hz) of various durations caused transient accumulation of Ke + which was non-linearly related to the duration of muscle activity. The peak values of Ke + in response to muscle stimulation were analogous in rabbits and cats, attaining values, e.g. after a 20-s isometric tetanus, between 8–9 mEq/lK+ in both species. |
2. | Potassium concentration in venous effluent blood (K ven + ) was transiently increased after isometric tetani. Since blood flow was measured at the same time, it was possible to calculate the amount of K+ lost by the muscle after tetani of various durations. A 32 g gastrocnemius muscle of the cat, for example, loses 9.36±1.52 EqK+ after a 20-s isometric tetanus, which corresponds roughly to 0.5% of the total muscle potassium content. The loss of K+ in this muscle was 29.3 pEq K+/impulse/100 g fresh muscle tissue. |
3. | There was no evident difference between the amount of K+ released during isometric tetani, or tetanic contractions performed under isotonic conditions. Single twitches evoked by indirect stimulation at 1 Hz for several minutes also induced a small rise in K ven + . |
4. | If the loss of K+ from the muscle into the blood stream is transiently prevented by arterio-venous occlusion installed immediately before a 10-s isometric tetanus, most K+ is released subsequently when blood flow is renewed, if the occlusion lasts for 20–25 s. It is not until blood flow is occluded for 40–60 s that most K+ is apparently resorbed and only a minor portion is released and is to be found in the venous blood. |
5. | The transient accumulation of muscle extracellular potassium may locally affect nerve endings, skeletal and smooth muscle cells. |
993.
H. Dlouhá B. Bíbr J. Ježek J. Zicha 《Pflügers Archiv : European journal of physiology》1976,366(2-3):277-279
Summary In 20, 40 and 60-day-old rats the filtration rate was studied, using Baines modification of Hanssen's Na4Fe(14CN)6 method enabeling the determination of single nephron glomerular filtration rate (SNGFR) ratio between superficial (S), intercortical (I) and juxtamedullary (J) nephrons. The proximal tubule lengths were determined as well. A close correlation was obtained between age and S/I, I/J and S/J of proximal tubule lengths and between age and I/J, S/J14C-activities of ferrocyanide. Presented findings confirm the data on the increasing role of superficial nephrons in the course of postnatal development of rat. 相似文献
994.
Puente-Maestu L Sánz ML Sánz P Nuñez A González F Whipp BJ 《European journal of applied physiology》2001,85(5):434-441
To be clinically useful as indices reflective of altered physiological function consequent to interventions in patients with
chronic obstructive pulmonary disease (COPD), the time constant (τ) and steady-state amplitude of the kinetic responses for
oxygen uptake (
) carbon dioxide output (
) ventilation (
) and heart rate (HR) have to be appropriately differentiable and reproducible. We therefore assessed the reproducibility
of τ and steady state amplitude values in 41 patients with severe COPD [mean (SD)] [forced expiratory volume in 1 s=41 (7)%
predicted], aged 64 (5) years. Of the total, 6 of the patients (15%) did not produce breath-by-breath data of sufficient quality
to warrant kinetic analysis. The remaining 35 patients completed two moderate-intensity 10 min square-wave exercise tests
separated by 2 h, both before and after an endurance training programme. Tests were conducted on an electromagnetically-braked
cycle ergometer at an exercise intensity corresponding to 80% of the estimated lactate threshold (θLa) or 50% of peak oxygen uptake if θLa was insufficiently differentiable. Breath-by-breath measurements of
,
,
and HR were averaged into 10 s bins and the on-transient response kinetics were estimated using a mono-exponential model.
Analysing the pre-training and the post-training test 1 and test 2 comparisons together, the test 1 –test 2 differences were
not significantly different from 0 for either τ or A. The standard deviation of the test 1 –test 2 differences allowed us
to define the magnitude of change that would reach statistical significance. For τ, this averaged some 8, 10, 11 and 8 s,
for
,
,
and HR, respectively, for a one-tailed paired-comparisons test (i.e. appropriate for assessing hypothesised improvements resulting
from an intervention); for a two-tailed comparison, the differences were approximately 2 s greater. The corresponding one-tailed
values for A were 100 ml·min–1, 95 ml·min–1, 2.5 1·min–1 and 4 beats·min–1, respectively; the two-tailed values were 10%–15% greater. We therefore conclude that both τ and A for moderate-intensity
exercise can be reproducibly estimated in patients with COPD when the data set provides a sufficiently large amplitude of
response and sufficiently low sample variability to allow appropriate parameter estimation.
Electronic Publication 相似文献
995.
Olivares A Cárdenas M Timossi C Zariñán T Díaz-Sánchez V Ulloa-Aguirre A 《Human reproduction (Oxford, England)》2000,15(11):2285-2291
The immunoreactivity of various LH and FSH calibration standards and recombinant preparations in the enzyme-linked immunoassay (EIA) systems for gonadotrophins developed for the Special Programme of Research in Human Reproduction of the World Health Organization (WHO) were compared. The preparations tested included three LH and two FSH pituitary standards (calibrated against LH 80/552 and 68/40 and FSH 78/549 respectively) provided with the EIA or radioimmunoassay WHO matched reagent kits, the pituitary preparation LER-907, and recombinant human LH (rhLH) and FSH (rhFSH). Simultaneous curve fitting of the EIA dose-response curves revealed no significant differences among the slopes generated by the WHO LH standards and LER-907; in contrast, no parallelism was found between the curves of rhLH and the pituitary-derived LH standards. No significant differences were found among the slopes of the curves elicited by the pituitary and recombinant FSH preparations. Each LH preparation exhibited a high degree of charge heterogeneity. Considerable variations in charge isoform distribution among the WHO LH standards, rhLH and LER-907 were also evident. In contrast, the FSH preparations were less heterogeneous and exhibited minor differences in charge distribution. Despite the existing differences in charge isoform distribution, all the pituitary-derived preparations as well as rhFSH seem appropriate for using as calibration standards in this particular EIA system. 相似文献
996.
Iborra A Palacio JR Ulcova-Gallova Z Martínez P 《American journal of reproductive immunology (New York, N.Y. : 1989)》2000,44(4):236-241
PROBLEM: The aim of this study was to investigate the humoral immune response to the female reproductive tissues associated with endometriosis (grades I-III) (n = 52), compared with a group of healthy fertile women (n = 6). METHOD OF STUDY: An ELISA with cultured endometrial cell lines in monolayer was used to determine the presence of anti-endometrial antibodies (AEA). For anti-zona pellucida antibodies (AZPA) assessment a conventional ELISA was employed. The presence of antibodies to human sperm (ASA) was performed by the tray agglutination test (TAT). RESULTS: Endometriosis grade III was associated with AEA in serum in the 45.4% of patients. The presence of AEA in serum is correlated to endometriosis severity. The 8.7% of women with endometriosis showed ASA, and the 10.9% of them were positive for AZPA. Antibodies specific for endometrial cells do not show reaction to any gamete antigen (sperm or oocyte), suggesting that they are not cross reactive. CONCLUSIONS: Severity of endometriosis is correlated with high titers of AEA. 相似文献
997.
998.
999.
Monteseirín J Bonilla I Chacón P Vega A Camacho MJ Guardia P Conde J Sobrino F 《Allergy》2003,58(10):1027-1032
BACKGROUND: CD14 is a most important monocyte surface molecule. Recently, it has been reported that there is an important relationship between CD14 and immunoglobulin E, and that regulation of CD14 expression is an effector mechanism mediating apoptosis of monocytes. OBJECTIVE: The present study was designed to determine whether specific allergens were able to modulate CD14 expression and apoptosis by monocytes from allergic patients or whether specific immunotherapy (IT) might affect these processes. METHODS: One group of adult allergic asthmatic patients had received IT for the previous 3 years. Another similar group was not treated with IT. We challenged peripheral blood monocytes from both groups of asthmatic patients in vitro with the specific allergen that produced clinical symptoms in asthmatic patients. The cells were also challenged with allergen to which the patients were not sensitive. Monocytes from normal subjects were also challenged with allergens. Expression of CD14 on the monocyte surface was analyzed by flow cytometry, and soluble CD14 (sCD14) in culture supernatant by enzyme-linked immunosorbent assay. The three groups of subjects were challenged with allergens, and apoptosis was analyzed by flow cytometry. RESULTS: When monocytes from non-IT-treated asthmatic patients were cultivated with the allergens to which the patients were sensitive, a significant up-regulation on the monocyte surface was observed compared with results from the healthy group (P < 0.003) and from the IT asthmatic group (P < 0.003). A significantly higher sCD14 level was observed in the culture supernatant of the monocytes from the IT asthmatic group were observed compared with those from the healthy group (P < 0.001) and those from the non-IT asthmatic group (P < 0.001). A significantly higher apoptosis level was observed in monocytes from the IT asthmatic group compared with those from the healthy group (P < 0.001) and those from the non-IT asthmatic group (<0.001). CONCLUSIONS: We present evidence that the expression of CD14 on the surface of monocytes and the apoptosis of the same cells can be modulated by an allergen-dependent mechanism. These processes can be affected by IT. 相似文献
1000.
Cardoso O Leitão R Figueiredo A Sousa JC Duarte A Peixe LV 《Microbial drug resistance (Larchmont, N.Y.)》2002,8(2):93-97
Resistance to carbapenems is emerging, and it is a great problem to therapeutics. Three isolates of Pseudomonas aeruginosa from a Portuguese hospital identified in urine and sputum, in 1995, presented a high-level resistance to imipenem (> 32 mg/L). Afterward, one isolate of P. aeruginosa recovered from urine of an ambulatory patient in 1998 showed high resistance to imipenem and meropenem. The resistance to carbapenems in these strains was associated with the production of a class B beta-lactamase, as was demonstrated by imipenem hydrolysis and inhibition by EDTA. Using primers described for bla(IMP) and bla(VIM), the amplification of the latter was observed in all isolates and a VIM-2 metallo-enzyme was identified. The pulsed-field gel electrophoresis (PFGE) patterns of these isolates were indistinguishable, suggesting dissemination to the community of this VIM-2 producer. 相似文献