Venodilator effects of adenosine triphosphate and sodium nitroprusside; Comparisons during controlled hypotension

Adenosine triphosphate as well as sodium nitroprusside has been used for hypotensive anesthesia. The purpose of this study was to examine the possibility that two hypotensive drugs may exert different effects on venous capacitance during controlled hypotension. In rats anesthetized with ketamine, mean arterial pressure was lowered to 50mmHg by intravenous infusion of adenosine triphosphate or sodium nitroprusside. Venous capacitance was assessed before and during induced hypotension by measuring the mean circulatory filling pressure (MCFP). MCFP was measured after briefly arresting the circulation by inflating an indwelling balloon in the right atrium. MCFP was lower during adenosine triphosphate-induced as well as sodium nitroprusside-induced hypotension as compared with the respective value at control (P < 0.01 for adenosine triphosphate and sodium nitroprusside). However, the decrease in MCFP by adenosine triphosphate (0.8 ± 0.1mmHg) was less (P < 0.01) than that by sodium nitroprusside (2.3 ± 0.3mmHg). These results suggest that at a comparable level of arterial hypotension venodilator effect of adenosine triphosphate was less than that of sodium nitroprusside. Less venodilatation during adenosine triphosphate-induced hypotension may contribute to the maintenance of cardiac output during hypotensive anesthesia.(Hoka S, Takeshita A, Aishima K et al.: Venodilator effects of adenosine triphosphate and sodium nitroprusside; comparisons during controlled hypotension. J Anesth 1: 144–147, 1987)     

Sodium regulation of agonist and antagonist binding to β-adrenoceptors in intact and Ns-deficient membranes

Summary Agonist binding to various hormone receptors mediating adenylate cyclase inhibition is decreased by sodium ions. We studied the influence of Na⁺ on agonist and antagonist binding to -adrenoceptors in membrane preparations of guinea pig lung, S49 lymphoma wild-type cells (WT) and their N_s-deficient cyc^– variants by measuring binding of the antagonist, [¹²⁵I]iodocyanopindolol ([¹²⁵I]CYP). At 37° C, sodium decreased the receptor affinity for the agonist, isoproterenol, in all three membrane preparations. In lung and WT membranes, Na⁺ steepened the shallow agonist competition curves in a manner similar to and synergistic with guanine nucleotides. When binding was performend at 4° C, sodium regulation but not guanine nucleotide regulation of agonist binding was preserved. At the low temperature, [¹²⁵I]CYP affinity was reduced, and sodium increased [¹²⁵I]CYP binding in both N_s-containing and N_s-deficient membranes by increasing the antagonist affinity without significant change in total receptor number. Compared to Na⁺, Li⁺ and K⁺ were much less potent and efficient in decreasing agonist and increasing antagonist binding. Na⁺ and Mg²⁺ had opposite effects on agonist binding in the N_s-containing lung and WT membranes but not in the N_s-deficient cyc^– membranes. The data indicate that sodium not only regulates binding of inhibitory hormone receptors but also agonist and antagonist binding to the adenylate cyclase stimulatory -adrenoceptor. The finding that sodium regulation of -adrenoceptor binding is also observed in the N_{s 2} cyc^– membranes, furthermore, indicates that the target of sodium is not the -subunit of N_s but possibly a component common to both types of receptor systems regulating adenylate cyclase activity.     

Effects of sodium and GTP on the binding kinetics of [3H]diprenorphine in NG 108-15 cell membranes

Summary Equilibrium binding isotherms of [³H]diprenorphine in membranes from NG 108-15 cells are consistent with a homogenous population of binding sites. Upon addition of Na⁺, Mg²⁺ and GTP, only a 2-fold reduction in affinity with a minor decrease in the number of sites is observed. Dissociation curves of [³H]diprenorphine, however, are clearly biphasic: in the absence of Na⁺, Mg²⁺ and GTP, 80% of the bound ligand dissociates slowly with at _1/2 of 100 min, and only 20% rapidly (t _1/2 4.5 min). In the presence of Mg²⁺, nearly all the binding is found in the slowly dissociating form. Upon the addition of either Na⁺ or GTP, 20–30% of the binding dissociates more rapidly. The rate constant of the rapidly dissociating form generated by Na⁺, however, is 2.5 times greater than that induced by the presence of GTP. Thus, the addition of both, Na⁺ and GTP, converts about 80% of the receptor into a very fast dissociating form (t _1/2 1.7 min).Exposure of intact cells to pertussis toxin (10 ng/ml) or treatment of membranes with N-ethyl maleimide (500 M), strongly reduces the proportion of the slowly dissociating component. Following these treatments, the effect of GTP is reduced or abolished, but that of Na⁺ remains unaffected.We conclude from these data that the effects of Na⁺ and GTP are not only distinct in site but also in mechanism of action and that there are three forms of opioid receptors that can be differentiated by their kinetic properties. The slowly dissociating receptor form requires a functional N unit.     

急诊经皮冠状动脉介入手术冠脉内应用硝普钠与替罗非班治疗老年急性心肌梗死效果及影响因素分析

目的探讨急诊经皮冠状动脉介入手术(Percutaneous Coronary Intervention,PCI)冠脉内应用硝普钠与替罗非班治疗老年急性心肌梗死效果及影响因素分析。方法收集153例急性心肌梗死老年患者,进行急诊PCI冠脉内应用硝普钠与替罗非班治疗(实验组)76例和急诊PCI冠脉内应用硝酸甘油与替罗非班治疗组(对照组)77例。追踪测评患者血清肌钙蛋白Ⅰ(Cardiac TroponinⅠ,cTnⅠ)、谷胱甘肽过氧化物酶(Glutathione,GSH)、超氧化物歧化酶(Superoxide Dismutase,SOD)、N末端B型钠尿肽前体(N-terminalpro-B-typenatriureticpeptide,NT-proBNP)、白介素-6(Interleukin-6,IL-6)、肿瘤坏死因子-α(Tumor Necrosis Factor-α,TNF-α)、内皮素(Endothelin,ET)、一氧化氮(NO)、血栓素B_2(Thromboxane B_2,TXB_2)、6酮-前列腺素F1α(6-keto-prostaglandin F1 alpha,6-keto-PGF1α)以及左心室射血分数(Left Ventricular Ejection Fraction,LVEF)、心肌梗死溶栓试验血流分级(Thrombolysis In Myocardial Infarction,TIMI分级)、心功能改善效果。结果实验组c TnⅠ、GSH、SOD、NT-pro BNP、IL-6、TNF-α、ET、NO、TXB_2、6-keto-PGF1α、LVEF、心功能改善效果、TIMI的追踪组间得分及复测组间得分差异有统计学意义(F=23.129、24.742、25.510、26.048、26.444、25.371、28.320、22.322、25.317、26.372、24.314、24.512、22.147,均P<0.05)。结论急诊PCI冠脉内应用硝普钠与替罗非班治疗老年急性心肌梗死患者对于心功能改善效果显著提高,并其受年龄、身体质量指数(Body Mass Index,BMI)、并发症、病变血管数量以及干预前心功能等级的影响。     

透明质酸钠关节内注射治疗膝骨性关节炎

目的　观察透明质酸钠注射液对膝骨关节炎的疗效。方法　关节内注射透明质酸钠 2ml,每周一次 ,5周一疗程 ,疗程结束后连续随诊一年半以上。结果　疗程结束时总有效率为 92 7% ,随访过程 82 %患者无疼痛、肿胀、渗出等症状复发。结论　透明质酸钠可有效地抑制膝骨关节炎患者的肿胀、渗出、疼痛等症状     

Effect of saline infusion on net reabsorption of endogenous sulfate relative to that of phosphate in intact and thyroparathyroidectomized rats

Clearance experiments have been performed to study the effects of saline infusion on the reabsorption of inorganic sulfate (SO₄) at endogenous levels. Adult female Sprague-Dawley rats on a standard diet were used. Both intact and thyroparathyroidectomized (TPTX) animals were infused with a 130 mmol/l sodium chloride solution at a low (0.15 ml/min) and a high (0.375 ml/min) rate. This increase of the infusion rate decreased the reabsorption of SO₄ in both groups of animals significantly. The fractional excretion of SO₄ in theintact rats increased from 9.9±5.6 to 18.4±3.6% (mean values±SD,p<0.001) and in theTPTX rats from 5.3±2.5 to 22.4±6.3% (p<0.001). It is concluded that endogenous parathyroid hormone has no major effect on the saline-induced inhibition of reabsorption of SO₄.This work was supported by a grant from the Deutsche Forschungsgemeinschaft (Fr 239/9-1)     

Altered gating and conductance of Na+ channels in hyperkalemic periodic paralysis

Electrophysiological studies on muscle fibres from patients with hyperkalemic periodic paralysis with myotonia have shown that the episodes of weakness are caused by a sustained depolarization of the sarcolemma to potentials between -40 and -60 mV. In muscle fibre segments from three such patients this sustained depolarization was caused by noninactivating Na⁺ channels with reduced single-channel conductance blocked by TTX and procainamide. As the chloride conductance was normal, myotonia may be best explained with the abnormal reopenings of the Na⁺ channels. The recently described genetic linkage between hyperkalemic periodic paralysis with myotonia and the gene coding for the TTX-sensitive Na⁺ channel suggests an altered primary structure of this channel causing its abnormal function.     

含有十二烷基磺酸钠的生物制剂的内毒素检测不能采用鲎试验

重组人ＩＬ－２在大肠杆菌表达时形成包含体，需经过变性和复性才具有生物学活性，在分离提取过程中常加一定量的ＳＤＳ，最低浓度每毫升不小于０．２５ｍｇ；低于此浓度会发生沉淀。鲎试验（ＬＡＬ试验）是一种灵敏度很高的检查生物制剂中致热源的常规方法。我们发现，当样本中ＳＤＳ的浓度＞０．０２５ｍｇ／ｍｌ时，可抑制尝试制的酶反应，使阳性结果转变为阴性。据此，我们建议，凡生物制剂中含有ＳＤＳ或其他酶抑制剂的产品，以尝试验来检查内毒素含量是没有意义的。     

Human myeloma light chains with increased molecular weight: high frequency among lambda chains

The discovery of a human myeloma protein comprising a kappa L-chain with an increased mol. wt of 30,000) (Bouvet et. al., 1980) prompted investigations on the incidence of such heavier L-chains among other human myeloma proteins. In 105 samples examined, 34 were found to have L-chains heavier than normal (23,000-24,000), ranging from 25,000 up to 31,000, and five of lighter mol. wt (21,000-22,000). These mol. wt abnormalities were detected by electrophoresis in sodium dodecyl sulfate 10% polyacrylamide gels (SDS-PAGE) after reduction with 2-mercaptoethanol. The mol. wt of three of the heavier kappa or lambda chains was also estimated by filtration through a Sephadex G100 column and by sedimentation equilibrium. All three methods indicated a mol. wt increase of about 15-25% as compared with the usual mol. wt. The distribution of the high mol. wt chains among all L-chains examined was found to be 11 out of 62 kappa chains (17.7%) and 23 out of 43 lambda chains (53%) (P less than 0.001). A preferential association of such L-chains with H-chains producing multiple bands in SDS-PAGE (P less than 0.01) and an association between multiple L-chain and multiple H-chain band (P less than 0.05) were also observed. In contrast, no abnormal L-chain was found in immunoglobulins from normal subjects. Spontaneous degradation of the normal H-chains sometimes yielded fragments of 30,000 mol. wt. These fragments were easily distinguishable from abnormal L-chains. The nature of extra mol. wt in heavy L-chains was investigated for the presence of carbohydrate moiety. Four large and three normal size L-chains were examined for amino-sugar and sialic acid content. A small amount (one residue per molecule) of amino-sugar was detected only in two normal and two heavy L-chains, whereas sialic acid was only found in the heaviest (27,000-30,000) L-chains (Lh) and in small percentage (one or two residues per molecule). Total sugar estimation in one Lh chain indicated a proportion not exceeding three or four residues per L-chain (mol. wt 1,000) and this is insufficient to explain the 15-25% (3,600-6,000) mol. wt increase. It is therefore possible that, at least in some heavy myeloma L-chains, an additional peptide is expressed. Whatever the nature of the increase it would be of interest to elucidate whether this is a marker of malignant process or of an intermediate step of normal Ig synthesis.     

The influence of sodium on growth in infancy

Sodium (Na) is an important growth factor, stimulating cell proliferation and protein synthesis and increasing cell mass. Sodium chloride (NaCl) deprivation inhibits growth, as reflected by reduced body and brain weight, length, muscle and brain protein and RNA content and brain lipid content compared with controls. This is not due to deficiency of other nutrients since control and experimental diets were identical except for NaCl content. Subsequent NaCl supplementation restores growth velocity to control values but does not induce catch-up growth. In humans, salt loss causes growth failure and subsequent salt repletion improves growth. Preterm infants <32 weeks' gestation at birth are renal salt losers in the first 2 weeks of post-natal life and are vulnerable to hyponatraemia. This can be prevented by increasing Na intake, which also produces accelerated weight gain that persists beyond the period of supplementation. Early nutrition in preterm infants can affect subsequent growth and also cognitive function: this is probably multifactorial, but NaCl intake differed substantially between study groups and is likely to be an important factor. The mechanism whereby Na promotes cell growth is not understood, but stimulation of the membrane Na⁺,H⁺-antiporter with alkalinization of the cell interior is a likely possibility.