hCG/ATP-induced Leydig cell calcium channel reaction at different extracellular calcium ion concentration

Objective: To study the calcium channel reaction of human Leydig cells induced by hCG/ATP at different extracellular calcium ion concentrations. Methods: The Leydig cell calcium ion concentration was examined with laser confocal microscope, when the cells were stimulated with hCG/ATP at different extracellular calcium contrations. Results: With calcium-containing extracellular fluid, the Leydig cells were sensitive to hCG stimulation and when the extracellular fluid was calcium-free, the Leydig cells did not respond to the stimulation. However, the Leydig cells did respond to ATP stimulation no matter the extracellular fluid contained calcium or not. Conclusion: In human Leydig cells, there are calcium channels sensitive to hCG and ATP. The extracellular calcium ion concentration plays an important role in the regulation of Leydig cell metabolism by hCG/ATP.     

CLINICAL NEUROPHARMACOLOGY OF CALCIUM ANTAGONISTS

Summary— Experimental and clinical data clearly demonstrate that calcium antagonists (CA) may have an action on the central nervous system (CNS). The cerebrovascular action of CA justifies their use in cerebral ischaemia, vasospasm and hypoxia. Several clinical trials have demonstrated such beneficial effects. On the other hand a number of reports indicate that CA may have a direct neuronal effect, although most of such trials have not been verified or are mere case reports. In addition, the large number of conditions susceptible to being corrected by CA is impressive: epilepsy, pain, dystonia, dyskinesia, psychiatric conditions, etc. Other papers are disconcerting that report extrapyramidal disorders induced by flunarizine and cinnarizine in the elderly, whereas nicardipine does not produce such side effects and may even alleviate some parkinsonian symptoms. In various experimental models (e.g. stroke, oedema), pharmacological effects have been shown to vary from one compound to the other. Two main questions are yet to be answered: 1) has the direct neuronal effect of CA been clearly established? 2) are the multiple clinical effects on the CNS really linked to calcium antagonism?     

Axonal neuropathy in a patient with monoclonal IgM kappa reactive with Schmidt-Lantermann incisures

We report a patient with a progressive, predominantly sensory neuropathy and a IgM kappa M-protein that binds to Schmidt-Lantermann incisures. A sural nerve biopsy showed primary axonal damage and IgM deposits at Schmidt-Lantermann incisures were seen by direct immunoperoxidase. Serum from the patient injected into rat sciatic nerve reacts with the incisures as with those in the patient's nerve. The IgM kappa M-protein reacts with chondroitin sulfate C and binds to a broad nerve protein band with a mobility of between 170 and 118 kDa. Peripheral neuropathy may be related to the M-protein, which had immunocytochemical reactivity not previously described for patients with polyneuropathy and IgM monoclonal gammopathy.     

多糖硫酸脂(PSS)治疗缺血性脑血管病临床观察和实验室研究

应用PSS治疗270例缺血性脑血管病并进行了临床、实验室以及动物试验的观察.总有效率为92.27%;显效率65.24%,与对照组相比较有显著性差异(P<0.005).实验室观察发现PSS有显著的抗凝血、降低血粘度,降低血脂及血管扩张作用.动物实验也说明了这一点.     

Cobalt-dependent potentiation of net inward current density in Helix aspersa neurons.

A low concentration of transition metal ions Co2+ and Ni2+ increases the inward current density in neurons from the land snail Helix aspersa. The currents were measured using a single electrode voltage-clamp/internal perfusion method under conditions in which the external Na+ was replaced by Tris+, the predominant external current carrying cation was Ca2+, and the internal perfusate contained 120 mM Cs+/0 K+; 30 mM tetraethylammonium (TEA) was added externally to block K+ current. In the presence of Co2+ (3 mM) or Ni2+ (0.5 mM) inward Ca2+ currents were stimulated normally by voltage-dependent activation of Ca2+ channels. There was a 5-10% decrease in the rate of rise of the inward current. The principal effect of Co2+ and Ni2+ in increasing the current density seems to be a decrease in the rate at which the inward currents decline during a depolarizing voltage pulse. The results may be due to a decrease in a voltage-dependent or Ca(2+)-dependent outward current and/or an inhibition of Ca2+ channel inactivation. Outward current under these conditions (zero internal K+) was significant and most likely due to Cs+ efflux through the voltage-activated or Ca(2+)-activated nonspecific cation channels. Co2+ is an extremely effective blocker of this outward current. These results are not an artifact of internal perfusion or the special ionic conditions. Intracellular recording of unperfused neurons in normal Helix Ringer's solution showed that the Ca(2+)-dependent action potential duration was increased significantly by low concentrations of Co2+. This result is consistant with the Co(2+)-dependent increase in inward (depolarizing) current seen in voltage-clamp experiments.     

Influence of a calcium dependent protease inhibitor on platelet activation and secretion

Continuous proteolysis resulting in consumption of major cytoskeletal proteins may be essential for platelet activation and aggregation. In this study we evaluated the effect of a known protease inhibitor, Leupeptin, on agonist induced platelet aggregation and secretion. Platelets exposed to 10 ugs/ml of Leupeptin did not aggregate in response to the action of thrombin (0.2u/ml). However, a concentration of Leupeptin as high as 250 ugs/ml did not prevent arachidonate induced aggregation and secretion. Leupeptin (100 ugs/ml) effectively blocked thrombin (0.2 u/ml) induced elevation of cytosolic calcium, but did not affect arachidonate induced elevation of platelet intracellular calcium levels. At a concentration of 100 ug/ml, Leupeptin effectively blocked thrombin (0.5u/ml) induced clot formation of platelet poor plasma, suggesting that it can exert its effect on thrombin by preventing fibrinogen degradation. Effective K_i for the competitive inhibition of thrombin induced hydrolysis of a chromogenic substrate, S2238, by Leupeptin was 2.4 uM. Leupeptin inhibition of platelet function was reversible by washing platelets free of the polypeptide. Results of our study demonstrate that Leupeptin inhibits thrombin induced platelet activation, probably by interfering with its proteolytic activity on the platelet surface membrane. However, inhibition of platelet surface membrane associated proteases did not prevent activation of platelets by other agonists.     

甲基黄酮醇胺盐酸盐对异丙肾上腺素正性频率作用的影响

本文比较了甲基黄酮醇胺盐酸盐(MFOA)、普萘洛尔(Pro)、维拉帕米(Ver)对异丙肾上腺素(Iso)所致兔离体右心房正性频率作用的影响。Pro使Iso累积浓度反应曲线平行右移,不抑制最大反应,属于典型的竞争性抑制剂,其pA2=8.43;MFOA和Ver使Iso量效曲线向下右移,抑制最大反应,为非竞争性拮抗。MFOA(2×10~(-5)M)和Ver(2×10~(-7)M)分别使最大反应下降19.28％和48.57％,其pD'2值分别为4.07±0.14、6.68±0.15。结果表明MFOA的作用不同于Pro,和Ver相似。     

Effect of intraperitoneally injected fluoride on plasma calcium in suckling and adult rats

Summary Sodium fluoride 10, 20, or 40 mg/kg body weight was given intraperitoneally to rats (6–11 days old and 90–95 days old). Blood analyses showed an initial increase in plasma fluoride concentration. The subsequent decrease in fluoride was paralleled by a decrease in total plasma calcium. These plasma concentrations were normal at blood collection 4 days after fluoride injection. The baby rats differed from the older rats in that their initial plasma calcium was higher and that the drop in plasma calcium concentration was less pronounced than in the old rats. A diet low in calcium and phosphate enhanced the effects of fluoride on total plasma calcium. The data indicate that the effect of large doses of fluoride on lowering the plasma calcium level is modified by the calcium intake.     

Simplified determination of serum cholesterol sulfate by gas-liquid chromatography combined with cyclohexylsilane-bonded phase column purification

Summary A new gas-liquid chromatographic (GLC) determination of cholesterol sulfate (CS) and dehydroepiandrosterone sulfate (DHEAS) for a biochemical diagnosis of recessive X-linked ichthyosis (RXLI) is described. Although the GLC method for determination of CS is known to be more sensitive than the thin layer chromatographic (TLC) method, the former method has not been widely employed because of its complicated pre-purification steps. The present method allows us to measure the serum levels of CS and DHEAS without tedious purification steps such as multiple conventional column chromatography and preparative thin layer chromatography. Sulfated steroids are rapidly purified with a commercially available mini disposable cyclohexylsilane-bonded phase (CH) column, CH BOND ELUT, and the purified steroids after desulfation are converted to water-resistant tert-butyldimethylsilyl ether derivatives for the GLC analysis on dual 2 m glass columns packed with 2% XE-60 on Chromosorb W.By the present method, serum CS concentrations in RXLI patients were shown to be about 10 times higher than those in patients with ichthyosis vulgaris, carriers of RXLI, and healthy subjects. This method is more suitable not only for a biochemical diagnosis of RXLI but also for studies on the metabolism of sulfated steroids than the previous time-consuming GLC methods.