Effect of cadmium on transmembrane Na+ and K+ transport systems in human erythrocytes.

The effects of cadmium (Cd2+) on Na+,K(+)-ATPase in disrupted human erythrocyte membranes and on various transmembrane Na+ and K+ transport systems in intact erythrocyte suspensions were studied. Cadmium2+ inhibited the erythrocyte Na+,K(+)-ATPase enzyme with a 50% inhibition at a Cd2+ concentration of 6.25 microM. The Cd2+ inhibition in the human erythrocyte was non-competitive with respect to Na+,K+, and ATP. Cadmium2+ exerted no acute effect, however, on the Na+,K(+)-ATPase pump activity as measured by the ouabain sensitive 86Rb uptake or Na+ efflux in intact red blood cells. Cadmium2+ also inhibited the Ca2+ dependent K+ channels in human red blood cells, whereas it had no effect on Na+,K+ cotransport, Na+,Li+ countertransport, anion carrier, and the number of active Na+ pump units. The data indicate that in human erythrocytes under acute conditions Cd2+ exerts an inhibitory effect on Na+,K(+)-ATPase enzyme in disrupted erythrocytes and the Ca2+ stimulated K+ efflux in intact red blood cells without affecting the Na+ pump, Na+,K+ cotransport, and Na+,Li+ countertransport activity.     

Effect of cadmium on transmembrane Na+ and K+ transport systems in human erythrocytes.

The effects of cadmium (Cd2+) on Na+,K(+)-ATPase in disrupted human erythrocyte membranes and on various transmembrane Na+ and K+ transport systems in intact erythrocyte suspensions were studied. Cadmium2+ inhibited the erythrocyte Na+,K(+)-ATPase enzyme with a 50% inhibition at a Cd2+ concentration of 6.25 microM. The Cd2+ inhibition in the human erythrocyte was non-competitive with respect to Na+,K+, and ATP. Cadmium2+ exerted no acute effect, however, on the Na+,K(+)-ATPase pump activity as measured by the ouabain sensitive 86Rb uptake or Na+ efflux in intact red blood cells. Cadmium2+ also inhibited the Ca2+ dependent K+ channels in human red blood cells, whereas it had no effect on Na+,K+ cotransport, Na+,Li+ countertransport, anion carrier, and the number of active Na+ pump units. The data indicate that in human erythrocytes under acute conditions Cd2+ exerts an inhibitory effect on Na+,K(+)-ATPase enzyme in disrupted erythrocytes and the Ca2+ stimulated K+ efflux in intact red blood cells without affecting the Na+ pump, Na+,K+ cotransport, and Na+,Li+ countertransport activity.     

Characteristics of catecholamine release from adrenal chromaffin cells cultured in medium containing ethanol--I. Spontaneous and K(+)-induced release.

Bovine adrenal chromaffin cells were dissociated and grown in primary culture for 9 days. Three days after plating, half the cultures were grown in a medium containing 200 mM ethanol and the other half in a control medium, for a further 6 days. The catecholamine content of the ethanol-treated cells was increased after 6 days of ethanol treatment, compared to control cells and there was a slight reduction in protein and DNA content. An enhanced spontaneous release of catecholamines was seen, which was Ca(2+)-dependent and was inhibited by cadmium but not by the organic dihydropyridine Ca2+ antagonist nitrendipine. The fraction of catecholamines released by K+ was also enhanced in ethanol-treated preparations, particularly at high K+ or Ca2+ concentrations. Release induced by K+ was sensitive to inhibition by both cadmium and organic dihydropyridine Ca2+ antagonists. The results show many similarities with changes observed in catecholaminergic transmission in rat brain during the development of ethanol physical dependence.     

Variables affecting measurement of human red cell Na+,K+ATPase activity: technical factors, feeding, aging

Because it has been suggested that decreased activity at the erythrocyte sodium pump might be the cause of age-related decreases in basal oxygen consumption, we have examined age-associated changes in Na+,K+-ATPase activity in red cell membranes. The initial portion of this study was directed toward elucidating possible methodological pitfalls in membrane preparation which might account for some of the variable results reported in prior erythrocyte Na+,K+-ATPase studies. We found that two of four red cell membrane fractions have substantial Mg2+-ATPase activity and contribute a significant portion of total membrane protein. As these two fractions contain little Na+,K+-ATPase activity their contamination of the other two fractions could cause significant variation in measured Na+,K+-ATPase activity. Additionally, we found that meal feeding raised Na+,K+-ATPase activity necessitating that measurements be made in the fasting state. With these methodological variables controlled, we found only a 10.8% coefficient of variation between fasting samples obtained on separate days in eight subjects. Using this methodology, we observed no correlation of Na+,K+-ATPase specific activity with age in males, and only a weak correlation in females who showed decreasing Na+,K+-ATPase specific activity occurring with advancing age. These observations suggest that changes in erythrocyte Na+,K+-ATPase activity do not cause the age-related fall in basal oxygen consumption.     

Interaction of xenobiotics on the glucose-transport system and the Na+/K(+)-ATPase of human skin fibroblasts.

The effects of individual and combined xenobiotics on functional properties of the plasma membrane of human skin fibroblasts were investigated. Good correlations between toxic effects on the D-glucose transport system or the Na+/K(+)-ATPase and the lipophilicity of the substances could be observed. The linear regression coefficients plotting log EC20 values (doses, leading to 20% inhibition) versus log Pow (octanol/water partition coefficient) were r = 0.95 (P less than 0.05). The combination of lipophilic with less lipophilic xenobiotics, such as pentachlorophenol with 4-chloroaniline, leads to additional effects. However, when the detergent sodium dodecyl benzenesulfonate was combined with the herbicide 2,4-dichlorophenoxyacetate (2,4-D), the toxic effect of 2,4-D on the Na+/K(+)-ATPase decreased considerably. The results support in general the assumption that the inhibition of integral functional proteins is based on an accumulation of xenobiotics in the plasma membrane, probably due to the enhanced membrane fluidity. Thus, the basic toxicity of xenobiotics can be predicted by their physicochemical properties.     

同日不同仪器测定99例次危重患者动脉全血与静脉血清中Na+、K+、Cl-结果的比较

目的探讨动、静脉血标本同日不同仪器测定Na^＋、K^＋、Cl^-结果的差异性。方法采用Rapidbab ^TM348血气分析仪测定患者动脉全血的Na^＋、K^＋、Cl^-数值；采用CHIRON／DIAGNOSTICS 644 Na^＋／K^＋/Cl^- Analyzer仪检测患者静脉血清的Na^＋、K^＋、Cl^-数值。结果静脉（V）血清测定的Na^＋、K^＋、Cl^-结果比动脉（A）全血测定的Na^＋、K^＋、Cl^-结果，平均值都稍高。但Na^＋、K^＋差异无显著性，t值分别为0．0679和0．5379，P均〉0．05；Cl^-则差异有显著性，t值为2．0225，P〈0．05。但由于检测对象均为危重患者，Na^＋、K^＋、Cl^-测定结果，无论是正常、减低或增高，时刻都在随着病情变化而动态变化，最为明显的是Na^＋、K^＋的低值，Cl^-低值变化不明显。但从总体上看，A与V样本Na^＋、K^＋、Cl^-测定结果的升高或减低都是相应同步的。结论A与V样本，两种仪器分别测定的Na^＋、K^＋、Cl^-结果，都是准确可信的，具有同样重要参考价值。     

Effect of Lead on Oxidative Stress, Na+K+ATPase Activity and Mitochondrial Electron Transport Chain Activity of the Brain of Clarias batrachus L.

The present invivo study was designed to elucidate the toxic effect of lead on oxidative stress, Na⁺K⁺ATPase and mitochondrial electron transport chain activity of the brain of Clarias batrachus. The fish were exposed to 10 and 20% of the derived 96 h LC₅₀ value, 37.8 and 75.6 mg L⁻¹, respectively, and sampled on 20, 40 and 60 days. Exposure of fish brain to lead demonstrated an increased production of reactive oxygen species, increased lipid peroxidation, loss of protein thiol groups in synaptosomal fraction with the decreased activity of Na⁺K⁺ATPase, partial inactivation of mitochondrial electron transport chain activity and energy depletion. However, no change in protein carbonyl content in synaptosomal fraction was observed due to lead exposure. Concluding the results of our investigation we suggest that lead exposure induces oxidative stress in the brain of Clarias batrachus and the decline in Na⁺K⁺ATPase activity was presumeably mediated by the combined action of lipid peroxidation and deficient mitochondrial electron transport chain activity.     

An increase in the Na+/K+-ATPase activity of erythrocyte membranes in workers employed in a lead refining factory.

To clarify the relationship between erythrocyte Na+/K+-ATPase activity and haematological findings, several clinical laboratory examinations were performed on 31 male workers employed in a scrap lead refining factory and, as controls, 50 male workers employed in railway construction. The results were: (1) Values for erythrocyte Na+/K+-ATPase activity, blood and urine lead, urine delta-aminolaevulinic acid, and urine coproporphyrin of lead workers were significantly higher than those of the controls (p less than 0.01). (2) A strongly positive relationship between blood lead and erythrocyte Na/K-ATPase activity was observed in lead workers (r = 0.473, p less than 0.01). (3) A strongly negative relationship between Na+/K+-ATPase activity and intracellular sodium was observed in both groups (lead workers; r = -0.601, p less than 0.01: controls; r = 0.595, p less than 0.01).     

An in vivo and in vitro study of erythrocyte membrane acetylcholinesterase, (Na+, K+)-ATPase and Mg2+-ATPase activities in basketball players on alpha-tocopherol supplementation. The role of L-carnitine

BACKGROUND & AIMS: Vitamin E (alpha-tocopherol, alpha-Te) and carnitine reduce lipid peroxidation. THE AIM WAS TO: To investigate the erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase activities in basketball players with or without alpha-Te supplementation, before and after training. In vitro, we aimed to find out any additional effect of L-carnitine (L-C) on the modulated enzyme activities. SUBJECTS AND METHODS: Blood was obtained from 10 players before (group A), after exercise (group B) and after 1 month on alpha-Te (200 mg/24 h orally) supplementation before (group C) and after the game (group D). Lactate, pyruvate, muscle enzyme activities and total antioxidant status (TAS) were measured with commercial kits. Catecholamines and alpha-Te were determined with HPLC methods and membrane enzyme activities spectrophotometrically. RESULTS: Lactate, pyruvate, muscle enzymes and catecholamine levels were increased (P<0.001) in all groups after training. Alpha-Te levels and Mg2+-ATPase activity remained unaltered before and after exercise. TAS was decreased in the groups after the game. AChE activity was increased in group B (P<0.01) and decreased in group D (P<0.01). After the exercise, Na+, K+-ATPase activity was increased in group B and remained unaltered in group D. In vitro incubation of membranes from group D with L-C resulted in a partially restoration of the membrane AChE activity, whereas Na+, K+-ATPase and Mg2+-ATPase activities were found unchanged. CONCLUSIONS: Alpha-Te supplementation in basketball players results in an increase of TAS and AChE activity, whereas the other enzyme activities were found unchanged. L-C addition may restore AChE activity, which was modulated by training in players on alpha-Te.     

The effect of diet on total antioxidant status, erythrocyte membrane Na+,K+-ATPase and Mg2+-ATPase activities in patients with classical galactosaemia

OBJECTIVE: Classical galactosaemia is characterized by high levels of galactose-1-phosphate (Gal-1-P), galactose and galactitol. In vitro studies have shown modulation of the rat brain Na+,K+-ATPase and Mg2+-ATPase activities by Gal-1-P. The aim of this study was to evaluate the erythrocyte membrane Na+,K+-ATPase and Mg2+-ATPase activities in galactosaemic patients and to correlate them to Gal-1-P, total antioxidant status (TAS) and membrane protein content (PC). PATIENTS AND METHODS: Nine patients (N=9) originally on "loose diet" (group B) were requested to follow their diet strictly (group A). Twelve healthy children were the controls (group C). The activities of the enzymes, TAS and Gal-1-P in blood were determined spectrophotometrically. In the in vitro study, erythrocyte membranes from controls were preincubated with Gal-1-P (300 microM), and then with l-cysteine (0.83 mM) or reduced glutathione (0.83 mM) whereas these from the patients with the antioxidants only. RESULTS: Na+,K+-ATPase, Mg2+-ATPase, TAS and PC were significantly (P<0.001) reduced (0.31+/-0.03, 1.7+/-0.2 micromol Pi/hxmg protein, 0.89+/-0.02 mmol/l, 36.8+/-2.0 g/l, respectively) in group B as compared with those of group A (0.58+/-0.06, 2.5+/-0.2 micromol Pi/hxmg protein, 1.41+/-0.11 mmol/l, 51.5+/-3.1g/l, respectively) and controls (0.67+/-0.05, 3.2+/-0.2 micromol Pi/hxmg protein, 1.65+/-0.12 mmol/l, 64.0+/-3.5 g/l, respectively). Gal-1-P levels in group B was significantly higher than those in group A and controls. Positive correlation coefficients were found between the enzyme activities, PC and TAS whereas Gal-1-P inversely correlated to the enzyme activities. Incubation of the erythrocyte membranes from the patients with the antioxidants failed to restore the activities of inhibited enzymes, whereas the inhibition by Gal-1-P in controls was reversed. CONCLUSIONS: High blood Gal-1-P concentrations resulted in low TAS and PC. The inhibition of Na+,K+-ATPase and Mg2+-ATPase may be due to the presence of free radicals and/or the elevated Gal-1-P.     

Toxicity of cypermethrin and fenitrothion on the hemolymph carbohydrates, head acetylcholinesterase, and thoracic muscle Na+, K+-ATPase of emerging honeybees (Apis mellifera mellifera. L)

Comparative effects of sublethal doses (0, 0.1, 0.2. 0.4, 0.8, and 1 nmol/bee) of cypermethrin and fenitrothion have been studied on emerging honeybees. The insecticides were injected intrathoracially between the third and the fourth segment. Biochemical effects were determined over a 3-h period. Both cypermethrin and fenitrothion led to a significant hypoglucosemia and hypotrehalosemia 15 min after injection, but cypermethrin seemed more active than fenitrothion at the same doses. A recovery phase appeared for glucosemia and trehalosemia, 60 min after injection. The higher toxicity of cypermethrin than fenitrothion also appeared in this period, where it took a longer time for honeybees to reestablish carbohydrate levels following cypermethrin than fenitrothion injections. The low values of the correlation coefficients (r) for glucose versus trehalose levels led to the supposition that no typical functional interaction between glucose and trehalose could be considered to be involved in this experience. Na+, K+-ATPases activity was significantly inhibited (P< 0.05) by cypermethrin and maximum percentage inhibition was reached (45%) at 1 nmol/bee. The kinetic analysis of honeybee's acetylcholinesterase inhibition by fenitrothion, indicated that this insecticide acts (P< 0.05) on acetylcholinesterase activity. The percentage inhibition exceeded 60% at 0.2 nmol/bee. This result revealed that in general cypermethrin and fenitrothion share common biochemical effects on carbohydrates, although their neurotoxic effects on honeybees might be different.     

白术对人妊娠子宫平滑肌细胞膜钙依赖钾通道电流的影响

目的:研究中药白术(Atractylodes macrocephala)对正常晚孕子宫平滑肌细胞及经白细胞介素6(Interleukin-6,IL-6)作用后的子宫平滑肌细胞钙依赖钾通道电流(BKca)的影响,以探讨白术对早产时宫缩的抑制作用及电生理机制。方法:①急性分离人晚孕子宫平滑肌细胞,采用Axopatchl-D膜片钳放大器测全细胞模式下的单个平滑肌细胞大电导的钙离子依赖钾通道电流(BKca);②测定灌流液中含不同浓度的白术时,子宫平滑肌细胞BKca的变化;③测定灌流液中含IL-6(10ng/ml)时全细胞模式下BKca;继而测定灌流液中含有不同浓度的白术时,子宫平滑肌细胞BKca的变化。结果:10ng/mlIL-6可抑制BKca的幅值约(36.9±13.7)%(n=10,P<0.01),灌流液中含2mg/ml白术时增强BKca的幅值约(36.7±22.6)%(n=10,P<0.01),对于IL-6作用后的细胞,2mg.mL-1白术增强BKca的幅值约(45.2±13.7)%(n=10,P<0.01)。结论:白术可以兴奋晚孕子宫平滑肌细胞及IL-6作用后的子宫平滑肌细胞的BKca,且对IL-6作用后的子宫平滑肌细胞BKca的兴奋作用强于对正常子宫平滑肌细胞,证明它有助于维持妊娠时子宫平滑肌的膜电位和静息状态,为开发中药治疗早产提供一定的理论依据。     

The prevalence of eating disorders in a U.K. college population: A reclassification of an earlier study

In 1981 we published a study of eating disorders in a college population using the Eating Attitudes Test entitled “Subclinical Anorexia Nervosa” (Button & Whitehouse, 1981). In view of recent developments in the classification of eating disorders, we have reexamined this data and reclassified high scoring subjects. Our findings, viewed in the context of other recent British studies, are not consistent with the apparent increase in prevalence of eating disorders in the U.S. Implications for the epidemiology and classification of eating disorders are discussed.     

曲古菌素A对K562细胞周期蛋白的影响

目的探讨曲古菌素A(TrichostatinA,TSA)对K562细胞增殖和细胞周期的影响。方法50～400nmol/L的TSA分别处理K562细胞12～60h后,MTT法检测K562细胞的生长活性;流式细胞仪(FCM)检测细胞凋亡;免疫组化检测24h不同浓度(100～300nmol/L)细胞周期素(cyclinE)、Rb(retinoblastoma,Rb)基因在K562细胞中的表达。结果TSA可呈时间及剂量依赖性抑制K562细胞的增殖,抑制率为37.83%～78.57%(P<0.01)。流式细胞仪检测K562细胞,凋亡率为14.38%～61.18%。免疫组化结果显示cyclinE的吸光度值分别为0.2154±0.2015、0.1501±0.1978、0.1183±0.0521与对照组0.3274±0.1093比较,差异有显著性(P<0.05);Rb蛋白的吸光度值分别为0.3017±0.1356、0.2134±0.1283、0.1527±0.0216与对照组0.4186±0.1870比较,差异也有显著性(P<0.05);随着TSA浓度增高而表达下调,呈剂量依赖性下调。结论TSA能干扰细胞周期进程,其作用机制诱导K562细胞的凋亡,下调cyclinE的表达,从而抑制其相应基因Rb的表达,调控G1/S期检测点有关。     

1，25-二羟基维生素D3对K562细胞周期及凋亡的影响

目的观察1，25-二羟基维生素D3[1，25（OH）2D3]对白血病细胞株K562细胞周期及细胞凋亡的作用。方法Western印迹检测维生素D受体（VDR）在K562细胞的表达；四噻唑蓝法（MTT）、AO／EB、流式细胞仪分析细胞生长抑制率、细胞凋亡率及细胞周期。结果（1）K562细胞核阳性表达VDR；（2）0-10^-6mol／L浓度的1，25（OH）2D3呈浓度依赖性抑制K562细胞增殖，10^-8mol／L 1，25（OH）2D3明显抑制K562细胞增殖，促进凋亡，细胞周期阻滞主要发生在G2期或M早期，凋亡率从4．1％（对照组）增至26．5％（P〈0．01）。结论1，25（OH）2D3可明显抑制K562细胞增殖，促进细胞凋亡。     

Aftermath of stroke: an epidemiological study in Melbourne, Australia.

A population-based study of the incidence of stroke was carried out in an urban area of Melbourne, Australia. The 508 cases were followed up and the survivors interviewed briefly at three months and in more depth six months after the onset of stroke. Fifty-eight per cent of all subjects had survived to six months, and the strongest prognostic indicator was level of consciousness at time of maximum impairment. By six months, 25% of all cases were independent in self-care and mobile outside the home; of those patients aged under 75 years, suffering a first stroke and retaining full consciousness at the time of maximum impairment, the proportion was 50%. A very imperfect correlation was present between residual physical impairment and return to the full range of prestroke activities.     

Squamous cell cancer of the maxillary sinus in Hokkaido, Japan: a case-control study.

A case-control study of squamous cell cancer of the maxillary sinus was performed in Hokkaido with 106 cases and 212 controls matched for sex, age (within five years), and residence (same health centre region). Univariate analyses showed that a history of chronic sinusitis (relative risk, RR = 3.2), nasal polyps (RR = 5.0), an occupational history of being a carpenter, joiner, furniture worker, or other woodworker (RR = 2.9), and current or past smoking habits (RR = 3.0) were statistically significant risk factors for men. No single item was a significant risk factor for women.