Endogenous digoxin-like immunoreactivity and erythrocyte sodium transport in uraemic patients undergoing dialysis

1. Erythrocyte Na+ transport (Na+ pump activity, co-transport, countertransport and passive Na+ efflux) and intracellular Na+ concentration were studied in 10 normal individuals and in 29 uraemic patients on chronic haemodialysis, before and after a haemodialysis session. Eight of them fulfilled the criteria of hypertension. 2. Normotensive patients before haemodialysis were classified in two groups: group 1 (pump-) with decreased erythrocyte Na+ pump activity, and group 2 (normal pump) with normal erythrocyte Na+ pump activity. Group 1 showed, compared with controls, a normal intracellular Na+ concentration and a decreased co-transport, but no difference in either countertransport or passive Na+ efflux. After haemodialysis this difference disappeared. Before haemodialysis, group 2 showed a high intracellular Na+ concentration, but activities of the Na+ transport systems studied were similar to those of controls. After haemodialysis, cell Na+ concentration decreased to a level not significantly different from that of controls. 3. Both before and after haemodialysis, hypertensive patients showed Na+ transport system activities and an intracellular Na+ concentration similar to those of controls. 4. Endogenous digoxin-like immunoreactivity (EDLI) and erythrocyte Na+ transport were studied in five normotensive and five hypertensive patients, before and after haemodialysis. EDLI in plasma was similar in both groups before and after haemodialysis. No correlation was found between EDLI and erythrocyte Na+ pump activity. 5. These results suggest the existence in some dialysed uraemic patients of alterations in erythrocyte Na+ fluxes, which may be corrected by haemodialysis. EDLI and erythrocyte Na+ fluxes do not seem to be markers of secondary hypertension in these patients.     

A comparison of endogenous digoxin-like immunoreactivity and sodium transport inhibitory activity in umbilical arterial and venous serum

1. Endogenous digoxin-like immunoreactivity (EDLI) was measured by radioimmunoassay for digoxin in 13 paired samples of arterial and venous umbilical cord serum. EDLI was present in vein and artery, but was higher in the venous samples (P less than 0.025). 2. The venous cord serum inhibited the ouabain-sensitive sodium efflux rate constant of a normal mixed leucocyte population when compared with the effect of arterial cord serum (P less than 0.005). 3. It is suggested that the placenta may be involved in the production or metabolism of neonatal EDLI and of the inhibitor of sodium transport.     

Evidence for an inhibitor of leucocyte sodium transport in the serum of neonates

1. In confirmation of previous studies, serum obtained from cord blood demonstrated endogenous digoxin-like immunoreactivity (EDLI). Sera from pregnant women in the third trimester also demonstrated EDLI, which disappeared after delivery. 2. Cord serum inhibited the total sodium efflux rate constant of a mixed leucocyte preparation when compared with the effect of control serum. This inhibition resulted from a depression of the ouabain-sensitive (sodium pump) component of the rate constant. 3. An ultrafiltrate of the serum (mol. wt. less than 30,000) also inhibited ouabain-sensitive leucocyte sodium transport when compared with filtrate obtained from control serum. 4. DHA-S Dehydroepiandrosterone sulphate (DHA-S) and cortisone, both present in high concentration in cord serum, demonstrated EDLI but did not affect leucocyte sodium transport in the cells of normal subjects. 5. DHA-S had no effect on sodium transport or vasoconstrictor activity in human omental resistance vessels. 6. It is concluded that EDLI of cord serum is associated with sodium transport inhibitory activity. This is unlikely to be attributable to DHA-S or cortisone.     

Comparison of five radioimmunoassays and enzyme bioassay for measurement of digoxin in blood.

Digoxin-containing sera from 86 patients were analyzed for this drug by bioassay and radioimmunoassay. Each serum was analyzed in duplicate by six procedures: inhibition of Na+-K+-dependent ATPase and five "kit" radioimmunoassays from four different commercial sources. Mean values for two of the radioimmunoassays differed significantly from those for the bioassay. One radioimmunoassay mean value was significantly different from the other five mean values. We conclude that normal values for digoxin radioimmunoassay should be determined for each kit, and should not be adopted from published data.     

Elevated serum concentrations of androgens in women with pregnancy-induced hypertension

Alterations of steroid hormone profiles have been suggested to be involved in the pathophysiology of pregnancy-induced hypertension (PIH). The aim of our study was first to investigate serum concentrations of testosterone, dihydrotestosterone, androstenedione and dehydroepiandrostenedione sulfate in women with PIH and normotensive pregnant women and secondly to evaluate an association between elevated serum concentrations of androgens and the development of severe disease. Serum concentrations of androgens were measured in 40 patients with PIH and 40 normotensive pregnant women, matched for gestational age, determined by enzyme linked immunosorbent assay. Multivariate logistic regression models were used to analyze the influence of elevated serum concentrations of androgens on the occurrence of PIH and the development of severe disease. The median serum concentrations of androstenedione and testosterone were significantly elevated in women with PIH compared to controls (6.3 and 5.0 ng/ml, 1.8 and 1.1 ng/ml, p = 0.005 and p = 0.04, respectively). The difference between the median serum concentrations of dihydrotestosterone and dehydroepiandrostenedione sulfate in women with PIH and controls was not significant. Elevated serum concentrations of androstenedione revealed a significant influence on the odds of presenting with PIH (p = 0.043) and were significantly associated with the development of severe disease (p = 0.014). Women with PIH have elevated serum concentrations of androstenedione and testosterone. Moreover, elevated serum concentrations of androstenedione are associated with development of severe disease.     

妊娠高血压综合征患者血清对内皮细胞释放血小板衍生生长因子的影响

目的　探讨血管内皮细胞 (ECV30 4 )经妊娠高血压综合征 (简称妊高征 )患者血清刺激后 ,培养上清液中的血小板衍生生长因子 (PDGF)与妊高征发生发展的关系。方法　采用酶联免疫吸附试验 (ELISA)定量检测体外培养血管内皮细胞上清液中的PDGF。结果　妊高征患者产前血清刺激血管内皮细胞释放PDGF的量明显高于妊高征患者产后组和正常孕妇产前、产后组 ,4组比较 ,差异有显著性 (P <0 .0 5 )。结论　妊高征患者产前、产后血清刺激血管内皮细胞释放的PDGF明显增加 ,提示PDGF参与了妊高征形成的相关病理生理机制     

Active sodium-urea counter-transport is inducible in the basolateral membrane of rat renal initial inner medullary collecting ducts.

Rat inner medullary collecting ducts (IMCD3s) possess a luminal Na+-dependent, active urea secretory transport process, which is upregulated by water diuresis. In this study of perfused IMCDs microdissected from base (IMCD1), middle (IMCD2), or tip (IMCD3) of the inner medulla, we tested whether furosemide diuresis alters active urea transport. Rats received furosemide (10 mg/d s.c. for 3-4 d) and were compared with pair-fed control rats. Furosemide significantly decreased urine osmolality and urea clearance, and increased blood urea nitrogen. IMCD3s from furosemide-treated rats had significantly lower rates of active urea secretion than IMCD3s from control rats. IMCD2s showed no active urea transport in control or furosemide-treated rats. IMCD1s from control rats had no active urea transport, but IMCD1s from furosemide-treated rats expressed significant rates of active urea reabsorption. In IMCD1s, this active urea reabsorptive transport process was inhibited by: (i) 0. 25 mM phloretin (bath); (ii) 1 mM ouabain (bath); and (iii) replacing bath Na+ with NMDG+; it was stimulated by 10 nM bumetanide (bath). In summary, we found that furosemide decreased active urea secretion in IMCD3s and induced active urea reabsorption in IMCD1s. The new Na+- dependent, active urea reabsorptive transport process may be a basolateral Na+-urea antiporter.     

Effects of oral contraceptives containing oestrogen combined with norethisterone or levonorgestrel on erythrocyte cation transport in normal women.

1. Studies were undertaken in pre-menopausal women to examine the effects of treatment with standard oestrogen-progestogen and progestogen-ony oral contraceptives on erythrocyte Na+,K+ co-transport and Na(+)-Na+ countertransport over 3- and 6-month periods. Concurrent observations were made on other erythrocyte cation transport components, plasma lipid concentrations, plasma renin activity, plasma aldosterone concentration and blood pressure. 2. Na+,K+ co-transport, measured as the ouabain-resistant, frusemide-sensitive component of 86Rb+ influx, and Na(+)-Na+ countertransport, measured as the ouabain-resistant, phloretin-sensitive component of 22Na+ influx, were both increased in women taking, on days 1-21 of their cycle, ethinyloestradiol (30-50 micrograms) combined with norethisterone (1000 micrograms or 500-1000 micrograms) for 3 or 6 months. Neither of these fluxes was increased in a control group of women, or in women treated for the same time periods with ethinyloestradiol combined with levonorgestrel. 3. In a separate study of erythrocyte cation transport (excluding Na(+)-Na+ countertransport), in which women undertook treatment with norethisterone only (350 micrograms/day) for 6 months starting 6 weeks post partum, no changes in Na+,K+ co-transport were observed at 3 or 6 months; there were no changes in cation transport in a corresponding control group. 4. The results of these studies confirm that certain oral contraceptive compounds can alter erythrocyte cation transport, and indicate that norethisterone in higher dose preparations is the component predominantly responsible. The alterations observed could not be explained by a direct link with concurrent changes in plasma triacylglycerol concentrations or in the renin-aldosterone axis and were not closely associated with elevation of blood pressure.     

Use of 86Rb and 22Na in assaying active and cotransport activities in human erythrocytes in a biracial population

A defect in Na+-K+ transport across the red cell membrane has been shown to be associated with essential hypertension. A sensitive assay system to measure active, co- and countertransport systems in erythrocytes from normotensive adults was developed. Active, co- and countertransport systems in the erythrocytes were assayed by measuring the influx of radioactive 22Na+ and 86Rb+. In the biracial (black-white) population group studied, analysis of variance of the active transport showed a significant race effect (p = 0.003). Cotransport activity showed age by race interaction (p = 0.001) and age by sex (p = 0.02). Cotransport activity was significantly higher in whites than blacks (p = 0.0001). Countertransport activity did not vary either by sex or race. Of the Spearman correlation coefficients for transport activities and blood pressure, white males showed a strong positive correlation with countertransport, whereas in black males, blood pressures showed a strong interaction with active transport. Among the transport activities, active transport showed significant interaction with countertransport activity in black males, whereas cotransport activity in whites showed a strong interaction with countertransport. The results suggest a subtle difference in Na+-K+ transport systems between blacks and whites, and these variations may be related to differences for susceptibility to essential hypertension.     

Human calcitonin radioimmunoassay: Characterization and application

A radioimmunoassay of human calcitonin (HCT) has been developed, employing antibodies formed in response to a HCT-bovine gamma globulin conjugate. The assay is sensitive (lower limits of detection 30 pg/ml serum), reproducible, and specific for intact HCT and carboxyl-terminal fragments of HCT. Serum HCT was detected in 76% of 63 normal subjects (mean ± S.E.M. = 72 ± 7 pg/ml), and was increased in cord sera, as well as sera from patients with chronic renal disease and medullary thyroid cancer. Increased levels were observed during calcium infusions into normal subjects, but not in sera from pregnant women or subjects with chronic hypercalcemia. No significant correlation was observed between serum ionized calcium and HCT in sera from 147 hospitalized patients. These findings suggest the usefulness of this assay for further studies of conditions affecting calcitonin homeostasis.     

Prostate specific antigen molecular forms in breast cyst fluid and serum of women with fibrocystic breast disease

We have analyzed matched serum and breast cyst fluid samples for total PSA from 148 patients with fibrocystic breast disease. We have also determined the molecular forms of PSA (free PSA and PSA bound to alpha1-antichymotrypsin) in 78 breast cyst fluid samples. We found that total PSA can be detected in all cyst fluids and in about 75% of female sera. The median total PSA concentration in breast cyst fluid (bcf) is about 30 times higher than the median in the corresponding sera. Breast cyst fluid and serum PSA are not correlated with each other. Total serum PSA is inversely associated with patient age but the inverse association between bcf PSA and age is weak. Lower total PSA in bcf was seen in women who breast feed, and higher bcf PSA is associated with multiple cysts. Type I cysts (with a high K+/ Na+ ratio) tend to have higher total PSA than Type II cysts. All but three of the fractionated cyst fluids (75/78; 96%) had free PSA as the predominant molecular form. The most consistent finding of our study was the positive association between the cyst fluid K+/Na+ ratio and the free to bound PSA ratio. This association was confirmed by Spearman correlation as well as by Wilcoxon and chi-square analysis. Secretory/apocrine cysts (Type I) tend to have more total PSA and proportionally more free PSA than transudative/flattened cysts (Type II).     

Reduced brain Na+, K+-ATPase activity in rats with galactosamine-induced hepatic failure: relationship to encephalopathy and cerebral oedema

Previously we have shown that sera from patients with fulminant hepatic failure (FHF) will inhibit partially purified rat brain Na+, K+-ATPase and sodium efflux from human leucocytes in vitro. Similar inhibition may be involved in the pathogenesis of encephalopathy and cerebral oedema in these patients. In the present study we have attempted to establish whether the activity of brain Na+, K+-ATPase is decreased in vivo in rats with D-galactosamine induced hepatic failure using homogenates of snap-frozen brains. Na+, K+-ATPase activity was significantly reduced in the forebrain region at the stage of mild encephalopathy (43 h after injection), while at the deeper stage of coma (43-53 h after injection) enzyme activity was further reduced in the forebrain region and was also significantly reduced in the hindbrain region. Ouabain insensitive ATPase activity was not significantly altered at any time. While a significant increase in the water content (0.5%) of the hindbrain region was found 43 h after galactosamine, there was no clear correlation between the development of cerebral oedema and the reduction of Na+, K+-ATPase activity. The activity of partially purified normal rat brain Na+, K+-ATPase was 15% lower when incubated with sera from rats in the deep stage of coma compared with control sera. These data support other evidence that the reduction in brain Na+, K+-ATPase is likely to be due to toxic substance circulating in serum which have been shown to inhibit this enzyme in vitro and to cause coma when administered to normal animals.     

Elevated serum levels in human pregnancy of a molecule immunochemically similar to eosinophil granule major basic protein

We have shown that serum levels of a molecule immunochemically similar to eosinophil granule major basic protein (MBP) are elevated in pregnant women throughout gestation. MBP levels increase during gestation and plateau at approximately 7,500 ng/ml by the 20th wk (greater than 10-fold above normal). Levels return to normal after delivery, with a T1/2 of 13.7 d. The MBP in pregnancy serum is remarkably similar to the eosinophil granule MBP in that: (a) pregnancy MBP fully inhibits the binding of radiolabeled MBP standard in a double antibody radioimmunoassay; (b) this inhibition reaction is specific for human MBP because pregnancy serum produces no inhibition of the binding of radiolabeled guinea pig MBP in the guinea pig MBP radioimmunoassay; (c) in a two-site immunoradiometric assay for MBP, slopes of dose- response curves for pregnancy serum, purified MBP, and serum from a patient with hypereosinophilic syndrome are identical, and maximal binding is comparable; (d) reduction and alkylation of pregnancy sera increases measured MBP 100-fold, as previously shown for eosinophil granule MBP in serum; and (e) the MBP in pregnancy serum demonstrates the same pattern of heat lability as has been previously reported for MBP. Four observations have raised the possibility that the eosinophil is not the source of the MBP in pregnancy serum: (a) no correlation between serum MBP level and peripheral blood eosinophil count exists in pregnant women, in contrast to previous studies of patients with eosinophilia; (b) levels of three other eosinophil-associated proteins are normal or low in pregnancy sera, whereas the serum levels of these proteins are elevated in patients with eosinophilia; (c) the slopes of dose-response curves for pregnancy sera and MBP standards differ in the double antibody radioimmunoassay; and (d) the molecule in pregnancy serum elutes from Sephadex G-50 columns at the void volume, while eosinophil granule MBP and the MBP in serum of patients with eosinophilia elute at a volume consistent with the previously established molecular weight of 9,300. These findings suggest that the MBP in pregnancy serum is derived from a source other than the eosinophil.     

妊高征患者血清尿素氮、肌酐和尿酸水平的变化

目的 通过测定妊娠高血压综合征孕妇血清尿素氮、肌酐和尿酸水平，探讨其临床意义。方法 采用生化分析仪测定50例妊娠高血压综合征孕妇（实验组）与43例正常妊娠的孕妇（对照组）血清尿素氮、肌酐和尿酸水平。结果 实验组血清尿素氮、肌酐浓度均高于对照组（P〈0．01）；血清中尿酸水平也显著增高（P〈0．005），血清尿素氮、肌酐、尿酸水平随着病情加重，均有升高趋势（P〈0．01）。结论 测定妊娠高血压综合征孕妇血清尿素氮、肌酐和尿酸对了解病情严重程度有一定的临床意义。     

A study of erythrocyte membrane cation transport adenosine triphosphatases in pregnancy-induced hypertension and of in vivo effects of diuretic treatment

Plasma and erythrocyte Na⁺ and K⁺ and erythrocyte membrane (EM) Na⁺, K⁺ ATPase, Mg²⁺ ATPase and Ca²⁺, Mg²⁺ ATPase activities were studied in four groups of women — non-pregnant, normal pregnant, with pregnancy edema (PE) and with pregnancy induced hypertension (PIH). The effect of diuretic therapy in PE and PIH was also evaluated. Plasma Na⁺ concentration was higher in PE and PIH. There was a significant reduction in (Na⁺ + K⁺ ratio between cell and plasma in these two groups. EM Na⁺, K⁺ ATPase was unaltered in PE and PIH. The Mg⁺ ATPase was elevated by 44% in PE and by 100% in PIH subjects. There was a 50% reduction in Ca²⁺, Mg²⁺ ATPase activity in PE. Diuretic therapy had no effect either on electrolyte levels or on any of the EM ATPases.From these results it may be concluded that Na, K, ATPase — which in kidney is a site of action for furosemide, a potent diuretic — is unaffected in PE and PIH and, hence, treatment with diuretics in such patients may be ineffective.     

妊娠高血压综合征血管内皮生长因子表达与围产儿结局的关系

目的　探讨在妊娠高血压综合征 (简称妊高征 )发病中血管内皮生长因子 (VEGF)对围产儿结局的影响。方法　分别采用酶联免疫吸附试验检测 4 0例妊高征孕妇的静脉血VEGF水平 ,免疫组化检测胎盘及蜕膜组织VEGF及CD34表达情况 ,详细记录围产儿的情况。并以 35例正常孕妇作对照。结果　①妊高征组孕妇的外周血VEGF水平及胎盘组织微血管密度 (MVD)明显低于正常妊娠组 (P <0 . 0 5 ) ;②两组胎盘绒毛滋养叶细胞和蜕膜组织中均有VEGF阳性表达 ,胎盘组织强阳性表达高于蜕膜。轻度妊高征与对照组比较 ,其胎盘组织VEGF强阳性表达的差异无显著性意义 ;而中度和重度妊高征与对照组相比 ,VEGF强阳性表达明显降低 ,其差异有显著性意义 (P <0 .0 5 )。各组孕妇蜕膜组织中的VEGF的表达强度的差异无显著性意义 ;③孕妇外周血VEGF水平与新生儿评分有关 ,与新生儿出生体重 (r =0 . 2 9;P <0 . 0 5 )和胎盘重量 (r =0 34;P <0 . 0 1)均存在直线正相关关系 ;与胎儿胎龄无明显关系。结论　妊高征孕妇血清VEGF水平和胎盘组织MVD降低 ,胎盘组织VEGF表达明显下降 ,VEGF可能对围产儿的结局有一定影响。     

"Anti-Ia reactivity in sera from patients with chronic active hepatitis (CAH)"

Anti-Ia reactivity in sera from patients with chronic active hepatitis (CAH) were characterized by determining cross-reacting specificities with the antigen defined by anti-Ia monoclonal antibody (MoAb) and by studying the effect of CAH sera on the autologous mixed leukocyte reaction (MLR). Preincubation with autoimmune CAH sera lowered the percentage of Ia+ non-T cells stained by anti-Ia MoAb. HBsAg+ve/HBeAg+ve sera did not exert any blocking activity while 4 out of 11 HBsAg+ve/anti-HBe+ve sera exerted a significant blocking effect. Preincubation of cells with normal human serum (NHS) plus aggregated IgG did not block the binding of MoAb anti-Ia. Sera from patients with autoimmune or HBsAg+ve/anti-HBe+ve CAH, that blocked the binding of anti-Ia MoAb to Ia positive target cells by more than 20%, clearly inhibited the autologous mixed lymphocyte reaction (MLR). Both IgG and IgM fractions obtained by affinity chromatography from CAH sera inhibited the autologous MLR and blocked the binding of anti-Ia antibody to Ia positive target cells. A significant positive correlation (p less than 0.001) between serum anti-Ia reactivity and serum liver membrane antibodies (LMA) was observed. In 4 "autoimmune" CAH patients, steroid treatment induced a dramatic decrease in the anti-Ia reactivity.     

Immunofluorometric demonstration and quantification of placental protein 5 in the absence of pregnancy

This time-resolved immunofluorometric assay (IFMA) developed for measurement of placental protein 5 (PP5) involves two antibodies: a monoclonal anti-PP5 antibody attached to a solid phase and an europium(III) chelate-labeled polyclonal anti-PP5 antibody as a tracer. The measuring range is 0.05-100 micrograms/L and the detection limit is 20 times lower than that of a PP5 radioimmunoassay (RIA) performed with the same polyclonal antiserum. By IFMA, PP5 could be detected and quantified in all plasma and serum samples of nonpregnant and pregnant individuals, whereas PP5 was undetectable by RIA in serum of healthy men and nonpregnant women. The mean concentration of PP5 in sera from men was 0.43 micrograms/L (SD 0.13, range 0.19-0.75, n = 47) and in sera from nonpregnant women 0.49 micrograms/L (SD 0.19, range 0.20-0.90, n = 41). PP5 concentrations in serum showed no systematic variation during the menstrual cycle. In serum samples from 60 pregnant women the results obtained by IFMA and RIA correlated well (r = 0.97).     

Characteristics of stimulation of H+ transport by aldosterone in turtle urinary bladder.

Aldosterone stimulates not only Na+ absorption but also urinary acidification. In this investigation the effects of aldosterone on H+ transport are examined in vitro in turtle bladder, a urinary membrane in which several of the factors controlling H+ transport have been defined. H+ transport was increased in bladder halves exposed to aldosterone compared to control halves. Stimulation of H+ secretion was observed as early as 1 h after addition of aldosterone and occurred before that of Na+ transport. In bladders depleted of endogenous substrate addition of glucose increased H+ transport more in aldosterone-treated halves (10.0+/-1.3 nmol/min) than in control halves (6.8+/-2.3). Addition of pyruvate failed to increase H+ transport (--0.3+/-0.7) in control halves but caused significant increments (2.4+/-0.5) in aldosterone-treated halves. In aldosterone-treated bladders glucose caused larger increments (16.5+/-2.7) in H+ transport than pyruvate (9.3+/-2.0) when halves of the same bladders were compared. Na+ transport, however, was equally increased by the two substrates. Despite the differences in time course and substrate requirements between the stimulation of H+ and Na+ transport, both increases were abolished by actinomycin-D. To examine the effect of aldosterone on the force of the H+ pump, protonmotive force, the pH gradient that would nullify the transport rate was determined with and without aldosterone. Aldosterone did not alter protonmotive force but significantly increased the slope of the H+ transport rate on the applied pH gradient. It is concluded that aldosterone stimulates H+ transport independently of Na+ transport. It increases the responsiveness of the transport rate to glucose and to a lesser extent pyruvate, an effect probably secondary to the increased transport rate. Equivalent circuit analysis indicates that aldosterone facilitates the flow of protons through the active transport pathway but does not increase the force of the pump.     

Effect of changes in dietary sodium on active electrolyte transport by erythrocytes at different stages of human pregnancy

1. Active electrolyte transport was examined in erythrocytes from women in the second and third trimesters of pregnancy and post partum, and compared with that in ovulating women. 2. There was a significant reduction in intracellular sodium ([Na]i) and increase in intracellular potassium ([K]i) in pregnancy with a return towards normal values in the post-partum period. 3. Maximum specific ouabain binding [number of Na+,K+-adenosine triphosphatase (Na+, K+-ATPase) units] was increased by 70% in pregnancy and returned slowly towards normal values post partum. 4. Na+,K+-ATPase activity as determined by ouabain-sensitive 86Rb influx in artificial media was also increased in pregnancy by 13%. It returned towards normal post partum. 5. The increases in Na+,K+-ATPase in pregnancy were not closely related to the concomitant increases in aldosterone or cholesterol nor to reticulocytosis and were not affected by 7 days of high (greater than 250 mmol/day) or low (less than 50 mmol/day) sodium intake.