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1.
The behaviour of sodium transport systems across the cell membrane has been poorly investigated in elderly hypertension. Sodium efflux driven by Na+/K+/Cl-cotransport activity was therefore investigated (using a novel NMR-spectroscopy method) in 5 elderly hypertensive males (mean age 78 +/- 5 years) and 5 normotensive controls (mean age 79 +/- 3 years). In order to exclude any change in cotransport activity secondary to metabolic abnormalities, both patients and controls were non-obese and had normal glucose and lipid metabolisms. The Na+/K+/Cl-cotransport evaluation was performed after three months of pharmacological wash-out, under a diet containing 120 mEq of Na+/day. The resulting data showed that Na+ efflux due to outward Na+/K+/Cl-cotransport was higher in hypertensive group than in the normotensive one (0.50 +/- 0.10 mmol Na+/l cells/hr. vs 0.33 +/- 0.03 mmol Na+/l cells/hr., respectively, p < 0.05). Intracellular Na+ content was similar in both groups. At variance with previous data from the literature, our findings indicate that the Na+/K+/Cl-cotransport activity is elevated in elderly hypertensives.  相似文献   

2.
We conducted this study to assess serum soluble E-selectin (sE-selectin) levels and erythrocyte membrane Na(+)K(+) ATPase activity in patients with rheumatoid arthritis (RA) and correlate the levels with disease activity. Levels of sE-selectin were measured in the serum of 20 patients with RA and 20 control subjects by an enzyme-linked immunosorbant assay. Na(+)K(+) ATPase activity was determined by a colorimetric method in RA patients and healthy controls. There were no statistically significant differences between the two groups with respect to demographic data such as age and sex (p > 0.05). The serum levels of sE-selectin, ESR and C-reactive protein (CRP) in RA patients were significantly higher than in healthy controls (p < 0.001). Erythrocyte membrane Na(+)K(+) ATPase activity was significantly lower in the RA group than in the control group (p < 0.001). Correlation analysis revealed significant positive correlations between soluble E-selectin and ESR (r = 0.457; p < 0.05) and CRP (r = 0.682; p < 0.01) levels. There were statistically significant negative correlations between erythrocyte membrane Na(+)K(+) ATPase activity and ESR (r = -0.450; p < 0.05) and CRP (r = -0.446; p < 0.05) levels. Additionally, a significant negative correlations between sE-selectin and Na(+)K(+) ATPase activity was observed (r = -0.80; p < 0.001). These results show that decreases in erythrocyte membrane Na(+)K(+) ATPase activity and increases in sE-selectin are observed in RA, and that increased levels of sE-selectin may also reflect disease status or activity.  相似文献   

3.
Changes in microsomal Na+, K+-, Mg2+- and Ca2+-ATPase activities during cell proliferation were examined in Chinese hamster V-79 (V-79) cells (normal cells) and human HeLaS-3 (HeLaS-3) cells (malignant cells). For V-79 cells, the Mg2+-ATPase activity per cell (pmol Pi/h/cell) in the confluent phase was higher than that in the logarithmically growing (log) phase. The amount of microsomal protein per cell was also high in the confluent phase. Specific activities (mumol Pi/h/mg protein) of Na+, K+-, Mg2+- and Ca2+-ATPase were significantly lower in the confluent phase than in the log phase. For HeLaS-3 cells, an increase in Ca2+-ATPase activity per cell was observed. The amount of microsomal protein per cell did not change between the log and confluent phase. The specific activity of Ca2+-ATPase in the confluent phase was also markedly higher than in the log phase. The relation between changes in ATPase activities and cell proliferation is discussed.  相似文献   

4.
In order to examine the involvement of insulin in the activity of Na+/glucose cotransporter in rat small intestine, we compared Na(+)-dependent uptake of D-glucose by brush-border membrane vesicles prepared from control, streptozotocin-induced diabetic, insulin-treated diabetic and starved diabetic rats. In four groups, the uptake of D-glucose showed a transient overshoot in the presence of Na+ gradient between medium and vesicles (medium greater than vesicles). The overshoot magnitude was increased (1.8-fold of controls) in diabetic brush border membrane vesicles and recovered to the control level by the treatment of diabetic rats with insulin. In contrast, increased uptake of D-glucose in diabetic rats was not recovered by the starvation of diabetic rats although the blood glucose level was the same as that of controls. Furthermore, we attempted to examine phlorizin binding activities among four groups. Scatchard analysis indicated that phlorizin binding to diabetic brush border membrane vesicles was increased (1.6-fold of controls) without a change of the affinity for phlorizin as compared with controls. Increased binding of phlorizin to diabetic brush border membrane vesicles was also recovered to the control level by the treatment of diabetic rats with insulin, but not by starvation. These results suggested that the increased activity of Na+/glucose cotransporter in diabetic rats was due to the increase of the number of cotransporter and that intestinal cotransporter was physiologically controlled by insulin, but not by blood glucose levels.  相似文献   

5.
In our previous report, we demonstrated that the functions of phagocytes and lymphocytes were defective in patients with systemic lupus erythematosus (SLE). In an attempt to further clarify the defective mechanisms of these cells, 25 active SLE, 10 bronchial asthma patients (BA) on corticosteroids and 25 age and sex-matched normal individuals were investigated for the expression of membraneous C3b receptors, ionophore-induced 45Ca(2+)-uptake, mitochondrial potentials and phagocytic activity of neutrophils. We found decreased expression of C3b receptors on SLE PMN in both resting (37.2 +/- 3.7% of the normal controls) and FMLP-stimulated (68.3 +/- 7.1% of the normal controls) conditions, whereas the C3b receptor expression on BA-PMN receiving long-term steroid treatment was not different from normal controls. This suggests that the defective phagocytosis of SLE PMN is in the recognition, but not in the ingestion phase because of the normal function of Ca(2+)-influx and mitochondrial activity in SLE PMN. On the other hand, hyporesponsiveness to PHA stimulation (stimulation index: 127.4 +/- 46.3 in SLE vs. 311.2 +/- 30.4 in normals, p = 0.0077) was a distinct cell-mediated immune abnormality in our SLE patients. We measured the membrane potential of individual cells using 3,3'-dihexyloxacarbocyanin and found hyperpolarization in resting SLE lymphocytes. However, the membrane polarization of SLE lymphocytes became lower than that of normal cells after PHA stimulation for 3 days. A similar tendency was also found in Na(+)-K(+)-dependent ATPase activity in SLE lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
The serum cortisol responses to D, L-5-hydroxytryptophan (5-HTP), 200 mg per oral, in unmedicated depressed and manic patients, were both significantly greater than that of normal controls. The cortisol response to 5-HTP in depressed patients was significantly correlated with ratings of specific symptoms of depression. It was also greater in non-psychotic than in psychotic depressed patients as well as in those manic or depressed patients who attempted suicide compared to those who had not. In view of evidence for decreased brain serotonergic activity in depression and perhaps mania, the results suggest at least some serotonin receptors may be supersensitive in some patients with affective disorders.  相似文献   

7.
The ouabain-sensitive (Na+ + K+)-ATPase activities of membrane fractions from hind-leg muscle and brain of normal and genetically dystrophic mice (C57BL/6J-dy strain) were studied, and the following results were obtained. 1) The ouabain-sensitive (Na+ + K+)-ATPase activity of frozen muscle sarcolemmal fraction from normal mice was several times higher than that of fresh one. 2) The ouabain-sensitive (Na+ + K+)-ATPase activity of frozen muscle sarcolemmal fraction from dystrophic mice was almost equal to that from normal one. But the muscle membrane yield from dystrophic mice was considerably low compared with the yield from normal one. 3) With brain membrane fractions, no differences were observed between normal and dystrophic mice in the ouabain-sensitive (Na+ + K+)-ATPase activity as well as in the yield of membrane fractions.  相似文献   

8.
The aim of the present study is to evaluate role of plasma antioxidants (albumin, bilirubin and uric acid) in patients suffering from type I Bipolar Disorder (BD-I) during different phases of illness: acute mania, euthymia and bipolar depression. Medical records of consecutive 110 BD-I patients (38 patients with acute mania, 35 in euthymic state, full remission, and 37 in depressive phase) were reviewed to evaluate plasma antioxidant levels. Laboratory data of 40 healthy controls were also obtained. The scores of Young Mania Rating Scale (YMRS), Bech-Rafaelsen Manic Rating Scale (BRMRS) and Hamilton Rating Scale for Depression (HAM-D) were evaluated. Serum uric acid levels were higher in acute mania than other patient subgroups and healthy controls. Serum uric acid levels directly correlated with BRMRS and YMRS scores. No differences were found between clinical groups during different phases and healthy controls concerning albumin and bilirubin. In conclusion, the results of the present study support the notion that serum uric acid levels may be higher in patients with BP-I (especially during manic phases) which may suggest a dysregulation of the purinergic system. However, limitations should be considered and further studies are needed.  相似文献   

9.
目的 :研究严重烧伤患者早期红细胞滤过指数 (EFI)与红细胞膜胆固醇含量、Na K ATPase活性的变化。探讨其在严重烧伤早期中的相互关系及意义。方法 :采用核孔滤膜法测定红细胞滤过指数 (EFI) ,用化学修饰电极法测定红细胞膜胆固醇含量 ,应用定磷法测定红细胞膜Na K ATPase活性。结果 :4 7例严重烧伤早期患者EFI较 6 0例正常对照组下降 (P <0 .0 1) ,红细胞膜胆固醇含量、Na K ATPase活性均高于正常对照组 (P <0 .0 1) ,且红细胞膜胆固醇含量、Na K ATPase活性与EFI呈密切负相关 (rcho =- 0 .871,rATPase =- 0 .80 1,P <0 .0 1)。结论 :严重烧伤早期EFI下降 ,变形性明显减低是导致血液粘度和微循环改变的原因之一 ,红细胞膜胆固醇含量和Na K ATPase活性的变化则是引起EFI下降、变形性减低的重要因素  相似文献   

10.
The Na,K-ATPase activity in microsomal fraction isolated from kidneys of winter hibernating ground squirrels was found to be 1.8–2.0-fold lower than that in active animals in summer. This is partially connected with a decrease in Na,K-ATPase protein content in these preparations (by 25%). Using antibodies to different isoforms of Na,K-ATPase α-subunit and analysis of enzyme inhibition by ouabain, it was found that the decrease in Na,K-ATPase activity during hibernation is not connected with change in isoenzyme composition. Seasonal changes of Na,K-ATPase a-subunit phosphory- lation level by endogenous protein kinases were not found. Proteins which could be potential regulators of Na,K-ATPase activity were not found among phosphorylated proteins of the microsomes. Analysis of the composition and properties of the lipid phase of microsomes showed that the total level of unsaturation of fatty acids and the lipid/protein ratio are not changed significantly during hibernation, whereas the cholesterol content in preparations from kidneys of hibernating ground squirrels is approximately twice higher than that in preparations from kidneys of active animals. However, using spin and fluorescent probes it was shown that this difference in cholesterol content does not affect the integral membrane micro-viscosity of microsomes. Using the cross-linking agent cupric phenanthroline, it was shown that Na,K-ATPase in mem- branes of microsomes from kidneys of hibernating ground squirrels is present in more aggregated state in comparison with membranes of microsomes from kidneys of active animals. We suggest that the decrease in Na,K-ATPase activity in kidneys of ground squirrels during hibernation is mainly connected with the aggregation of proteins in plasma membrane.  相似文献   

11.
Abnormalities of intracellular ion concentrations and transmembrane fluxes were reported in uremia. In RBC from 12 chronically hemodialyzed patients (age 41 + 12, 7 men, 5 women; mean dialysis duration 31 + 24 months), we evaluated the acute effects of hemodialysis on intracellular Na and K concentrations, ouabain sensitive Na/K pump, furosemide sensitive Na/K cotransport, Na/Li countertransport, and passive permeability to Na. Six patients were normotensive and 6 were taking antihypertensive drugs which were withdrawn before the study. When compared to our normal reference group, uremic patients showed a significant increase in intracellular K concentration and a significant decrease in ouabain-sensitive Na/K pump. Intracellular sodium was not increased. No correlation was found between the activity of sodium-potassium pump and the duration of hemodialysis. The other transport systems were comparable to normal. No significant change was observed between the values measured before and after dialysis. Ouabain sensitive Na/K pump was lower in hypertensive as compared to normotensive patients, but this difference was not significant. Our data support the existence of ion transport derangements in uremia, which are not acutely affected by hemodialysis.  相似文献   

12.
The authors present the results of a simultaneous assay of: intracellular Na+ and K+ concentrations, Na+ and K+ outward bumetanide-sensitive effluxes (Na+, K+ cotransport), Na+ efflux stimulated by extracellular Li+ (Na+, Li+ countertransport), and ouabain- and bumetanide-resistant Na+ and K+ effluxes (passive membrane permeability) performed in red blood cells from 15 uremic patients an regular hemodialysis and from 12 normal subjects, with an established flux assay. Na+ and K+ effluxes by the Na+, K+ cotransport system were significantly (p less than 0.01) lower in uremic patients then in normals (219 +/- 37 vs 82 +/- 17 mumol/l RBC/h and 251 +/- 29 vs 139 +/- 14 mumol/l RBC/h respectively). In normal subjects the bumetanide sensitive Na+ and K+ effluxes were strongly (r = 0.89; p less than 0.01) intercorrelated; and the intracellular Na+ concentration was related to the outward Na+ cotransport flux (r = 0.53; p approximately 0.05). Among uremic patients these correlations were not found. Na+ and K+ intracellular concentrations, passive Na+ and K+ permeability, and Na+, Li+ countertransport activity were not different among uremic patients and normal controls. In conclusion, in uremic dialyzed patients, red blood cell Na+, K+ cotransport activity is quite uniformly suppressed. The possible pathogenesis of this disfunction is still speculative and deserves further studies.  相似文献   

13.
Sex and age alter plasma membranes of cultured fibroblasts   总被引:1,自引:0,他引:1  
Human skin fibroblasts were taken from age-matched male and female subjects. The cells were then cultured under identical conditions and passage-number matched. Plasma membranes were isolated and membrane enzyme activities, lipid composition, and structure of isolated plasma membranes were measured in order to determine the presence of significant sex differences in human fibroblast membrane properties. The results indicated that plasma membranes from normal female subjects had a 1.6-fold and 3.6-fold higher cholesterol/phospholipid ratio and oleic acid (18:2) content than normal male subjects. The limiting anisotropy and the rotational relaxation time of fluorescence probe molecules such as trans-parinaric acid and 1,6-diphenyl-1,3,5-hexatriene in the plasma membranes was not significantly different from fibroblasts of male versus female normal subjects. The total activity of plasma membrane (Na+, K+)-ATPase was significantly higher in female than male normal subjects. A potential 'membrane structural disorder', Huntington's disease, was confirmed in fibroblast membranes from male but not from female Huntington's disease subjects. The possibility that Huntington's disease was a 'premature membrane aging' phenomenon was considered. A comparison of plasma membrane enzymes, lipids, and structure from old and young Huntington's disease subjects did not show differences consistent with accelerated membrane aging as explaining the molecular basis for the disease. The age-dependent differences noted in aged Huntington's disease subjects: increased phosphatidylcholine/phosphatidylethanolamine ratio and sphingomyelin + lysophosphatidylcholine content of fibroblast plasma membranes were not significantly altered when compared to normal age-matched controls. However, (Na+, K+)-ATPase activity was significantly enhanced in fibroblast plasma membranes of older Huntington's disease subjects unlike those of control subjects. In conclusion, sex and age differences in membrane properties of cultured cells represent important potential variables in the elucidation of human genetic disorders that may be membrane-related.  相似文献   

14.
Changes in intestinal transport of L-amino acid and D-glucose in streptozotocin (STZ)-induced hyperglycemic guinea-pig were examined using brush-border membrane vesicles. The vesicles were prepared from guinea-pigs on days 3, 10, and 21 after intravenous injection of STZ (150 mg/kg body weight), and from control animals injected with sodium citrate buffer (pH 4.5) in the same manner. Blood glucose concentration rose to greater than 300 mg/dl in the hyperglycemic guinea-pigs 24 h after STZ injection, and then remained constant. All vesicles obtained under different conditions showed a similar specific activity of alkaline phosphatase, a marker enzyme of the intestinal brush-border membrane, indicating a similar purity of the membrane vesicles. On day 3, Na(+)-dependent amino acid transport was found to be approx. 30% higher in the hyperglycemic than in the control group, and Na(+)-dependent glucose transport was 35% lower in the hyperglycemic than in the control group. On days 10 and 21, Na(+)-dependent amino acid transport had recovered to the control levels, whereas Na(+)-dependent glucose transport was twice as high as in the hyperglycemic than in the control group. Na(+)-independent amino acid and Na(+)-independent glucose transport showed no difference between the hyperglycemic and control groups after STZ injection. The changes in both Na(+)-dependent amino acid and glucose transport were attributed to significant changes in the Vmax values with no change in the apparent Km values. This study clearly demonstrates that hyperglycemia is associated with reciprocal changes in intestinal transport of amino acid and glucose in its acute phase, suggesting an important pathophysiological regulatory mechanism for absorption of nutrients by control of the numbers of specific carriers.  相似文献   

15.
Membrane Anomalies in Huntington''s Disease Fibroblasts   总被引:1,自引:0,他引:1  
Plasma membranes, microsomes, and mitochondria were isolated from paired, passage number matched, cultured human fibroblasts. The cells were obtained from skin biopsies of Huntington's disease (HD) subjects and from sex and age matched controls. All fibroblasts were cultured in identical media for three to seven passages. Enrichment of surface marker enzymes such as Na+,K+-ATPase indicated a 10-fold purification of the isolated plasma membrane. The specific activity of Na+,K+-ATPase was 62 and 82% greater in the crude homogenate and isolated plasma membrane, respectively, of HD fibroblasts than in control fibroblasts. The specific activity of plasma membrane Na+,K+-ATPase was correlated with lipid composition and with membrane structure as determined by measurement of the rotational relaxation time and limiting anisotropy of fluorescence probe molecules. Major alterations in the structure of the plasma membranes in HD fibroblasts were not noted. The rotational relaxation time and limiting anisotropy of 1,6-diphenyl-1,3,5-hexatriene and of trans-parinaric acid were not significantly different between the plasma membrane, microsomes, or mitochondria of HD versus those of control fibroblasts. trans-Parinaric acid demonstrated the coexistence of fluid and solid domains in all three subcellular membrane fractions of the normal and HD skin fibroblasts. Lastly, both trans-parinaric acid and 1,6-diphenyl-1,3,5-hexatriene displayed characteristic breakpoints in Arrhenius plots of absorbance corrected fluorescence in plasma membranes, microsomes, and mitochondria. In all cases, similar breakpoint temperatures, indicative of phase alterations, were noted near 20 degrees and 30 degrees C. These breakpoints were unaltered in HD. In summary, the data do not support the concept of major membrane structural defects in HD.  相似文献   

16.
The patch-clamp technique was used to study the properties and the density of conducting K and Na channels in the apical membrane of rat cortical collecting tubule. The predominant K channel observed in cell- attached patches (SK channels) had an outward single-channel conductance (with LiCl in the pipette) of 10 pS. The inward conductance (with KCl in the pipette) was 42 pS. The channel had a high open probability that increased with depolarization. Kinetic analysis indicated the presence of a single open state and two closed states. Increasing K intake by maintaining animals on a high K diet for 12-16 d increased the number of SK channels per patch by threefold (0.7- 2.0/patch) over control levels. In addition, conducting Na-selective channels, which were not observed in control animals, were seen at low density (0.5/patch). These channels had properties similar to those observed when the animals were on a low Na diet, except that the mean open probability (0.84) was higher. In other experiments, the whole- cell patch clamp technique was used to measure Na channel activity (as amiloride-sensitive current, INa) and Na pump activity (as ouabain- sensitive current, Ipump). In animals on a high K diet, INa was greater than in controls but much less than in rats on a low Na diet. Ipump was greater after K loading than in controls or Na-depleted animals. These K diet-dependent effects were not accompanied by a significant increase in plasma aldosterone concentrations. To further investigate the relationship between K channel activity and mineralocorticoids, rats were maintained on a low Na diet to increase endogenous aldosterone secretion. Under these conditions, no increase in SK channel density was observed, although there was a large increase in the number of Na channels (to 2.7/patch). Aldosterone was also administered exogenously through osmotic minipumps. As with the low Na diet, there was no change in the density of conducting SK channels, although Na channel activity was induced. These results suggest that SK channels, Na channels and Na/K pumps are regulated during changes in K intake by factors other than aldosterone.  相似文献   

17.
To evaluate the enzyme functional changes the Na+,K+-ATPase activity in membrane fraction of human colorectal adenocarcinoma at II and III cancer stages (according to TNM classification) of varying degrees of differentiation has been investigated. The decrease of the Na+,K+-ATPase activity in comparison with conditionally normal tissue of macroscopically unchanged mucosa was revealed in the tumor membrane preparations. Such changes of the Na+,K+-ATPase activity were higher at low differentiation grade and were less pronounced in moderately and highly differentiated adenocarcinomas. At the same time the changes in Na+,K+-ATPase activity have not been revealed between tumor membrane preparations at studied cancer stages when the degree of differentiation was not taken into account. It is supposed that Na+,K+-ATPase functional specificity occurs in colorectal adenocarcinomas and it is associated with tumor differentiation.  相似文献   

18.
Haptoglobin is an acute phase glycoprotein, secreted by hepatocytes and other types of cells including keratinocytes. Haptoglobin has been suggested to impair the immune response, inhibit gelatinases in the extracellular matrix and promote angiogenesis, but its role in psoriasis is obscure to date. Changes in haptoglobin glycan structure were observed in several diseases. The aim of this study was to investigate whether haptoglobin displays glycan variations in psoriasis. We found that the pattern of plasma haptoglobin glycoforms, following two-dimensional electrophoresis, exhibited significant quantitative differences in spot intensities between patients and controls. Quantitative and qualitative differences in glycan mass, between patients and controls, were found by mass spectrometry of glycopeptides from tryptic digests of protein isolated from both patients and controls. The number of distinct fucosylated glycoforms of peptides NLFLNHSENATAK and MVSHHNLTTGATLINEQWLLTTAK was higher in patients than in controls, but no fucosylated glycan was detected on peptide VVLHPNYSQ-VDIGLIK in either case. The number of peptides with distinct triantennary and tetraantennary glycans was higher in patients than in controls. Abundance or structure of specific glycans, which are present in haptoglobin from patients and are different or missing in normal haptoglobin, might be associated with disease activity.  相似文献   

19.
We evaluated the spontaneous IL17, IFNgamma and IL10 production by peripheral blood mononuclear cells from patients affected by clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) both in acute phase and in remission, relapsing remitting MS (RRMS) both in relapse and in remission, not-relapsing secondary progressive MS (SPMS) and controls. We observed higher IL17 levels in CIS patients both in acute phase and in remission than in SPMS patients and controls. On the contrary no difference in IL17 production was observed among RRMS patients and CIS, SPMS patients and controls. IFNgamma levels were significantly higher in CIS patients in acute phase than in CIS and RRMS patients in remission, SPMS patients and controls. Moreover, we observed higher IFNgamma spontaneous production in relapsing RRMS patients than in remitting RRMS and SPMS patients and controls. IL10 levels were significantly higher in remitting CIS and in relapsing RRMS patients than in SPMS patients and controls. There was no difference in IFNgamma, IL10 and IL17 levels between SPMS patients and controls. Our data suggest that IL17 might play a crucial role mainly in the early phase of MS, while IFNgamma seems to be involved both in the early phase and in the following relapses of the disease.  相似文献   

20.
Effect of ABA on the activity of mitochondrial membrane bound Na+-K+ATPase during isolation of mitochondria from soybean cotyledons, there was an increased activity of the mitochondrial membrane bound Na+-K+ATPase if abscisic acid (ABA) was added to the medium when soybean seedling were grown at 27 ℃ or 16℃, 40 mol/L ABA could change the turning point temperature of Arrhenius the activation energies (Ea) of Na+-K+ATPase from 36.6℃ or 22.7℃ decreased to 30. 3℃ or 17.8℃ respectively. The Km value and S0.5 value for this enzyme with ABA was higher than that without ABA. Hill coefficient (n) of this enzyme with ABA was 1.01 and without ABA was 1.89. The o2 uptake of mitochondria also increased. These results showed that the temperature of phase transition of mitochondrial membrane were decreased by ABA treatment.  相似文献   

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