Electrocrystallization of calcium carbonate on carbon-based electrodes

Calcium carbonate was deposited by electrochemical reduction of oxygen to hydroxyl ions at various carbon-based electrodes. Although some vaterite was observed during earlier stages of the electrodeposition, the predominant polymorph during later stages was calcite. The average crystal size reached a value of 15 μm after 10 h at a glassy carbon electrode but the crystal growth rate was substantially accelerated when oxygen was catalytically reduced. The same average size of the calcite crystals in this case (Pt/C electrode) was reached within a period of 1.5 h. Efficient removal of CaCO₃ from water was demonstrated when using a porous aerogel carbon electrode and a potential sufficiently negative to promote reduction of water molecules within the pores.     

The Effects of Zero Magnesium Dialysate and Magnesium Supplements on Ionised Calcium Concentration in Patients on Regular Dialysis Treatment

The effect of oral magnesium carbonate aluminium hydroxide onserum ionised calcium, total calcium, aluminium and magnesium,was assessed in 31 patients with chronic renal failure, duringand after one haemodialysis. The behaviour of ionised calcium and total calcium was the samein both groups. Each showed a slight fall during dialysis, whichwas not significant. Serum total calcium was 0.2–0.3 mmol/l(0.8–1.2 mg/dl) greater throughout the period of dialysisin the group taking aluminium hydroxide. Serum magnesium andaluminium were both lower in the group treated with magnesiumcarbonate. In the group taking magnesium carbonate, serum magnesium concentrationsfell markedly during dialysis, but otherwise were maintainedwithin the reference range by the use of a magnesium-free dialysate.These results show the effectiveness of magnesium carbonateoral phosphate-binding agents and zero magnesium dialysate inreducing serum aluminium without affecting the behaviour ofserum calcium fractions during dialysis.     

Direct cadiac electorphysiologic effects of sufentanil and vecuronium in isolated guinea-pig hearts

Sufentanil and vecuronium are commonly used simultaneously in anaesthesia. Bradycardia and asystole have been described immediately after the administration of these two compounds. Therefore, the purpose of the present study was to evaluate the direct cardiac effects of sufentanil and vecuronium in all parts of the cardiac pacemaker and conduction system.
The electrophysiological effects of sufentanil and vecuronium were studied in isolated spontaneously beating guinea-pig hearts perfused by the method of Langendorff. At a concentration of 0.1 μmol/1 sufentanil a significant reduction of the spontaneous sinus rate, prolongation of atrioventricular, intraventricular and His' bundle conduction could be observed. The highest concentration of 10 μmol/1 of sufentanil led to an overall slowing of conduction velocity and to an profound slowing of spontaneous sinus rate. AV nodal as well as atrial and ventricular refractoriness were markedly prolonged at this high concentration of sufentanil. In contrast, during perfusion with vecuronium at a concentration of 0.1 μmol/1 up to 10 μmol/1 no significant effects on cardiac conduction and pacemaker activity could be observed.
In conclusion, the electrophysiological effects of sufentanil are comparable to that of unspecific calcium antagonists. Therefore, especially in patients with a preexisting damage of the cardiac conduction system, the indirect effect of the combination of sufentanil and vecuronium which is predominantly responsible for bradycardia and asystole may be worsened by the direct effects of sufentanil.     

Prevention of early postmenopausal bone loss using low doses of conjugated estrogens and the non-hormonal,bone-active drug ipriflavone

Hormone replacement therapy is the optimal therapeutic choice for postmenopausal syndrome. While low doses of estrogens (0.3 mg/day of conjugated estrogens) can counteract neurovegetative menopausal symptoms, higher doses (0.625 mg/day of conjugated estrogens) are required to prevent bone loss in postmenopausal women. Experimental and clinical studies have shown that ipriflavone, a non-hormonal isoflavone derivative, is effective in the prevention and treatment of postmenopausal osteoporosis. The aim of the present investigation was to evaluate the efficacy and toler-ability of ipriflavone and very low doses of equine conjugated estrogens on bone loss in early postmenopausal women. Eighty-three healthy postmenopausal women (50.3±0.7 years) were enrolled for this 1-year multicenter study. All subjects were randomly allocated to receive: double placebo (n=24; group A), placebo plus conjugated equine estrogens 0.30 mg/day (n=31; group B) or conjugated equine estrogens 0.30 mg/day plus oral ipriflavone 200 mg tris in die at meals (n=28; group C), according to a double-masked design. Among women who completed the treatment period (valid completers), those of group A showed a progressive decrease in forearm bone density (FBD; measured by dual photon absorptiometry) that reached 1.7% after 12 months. The women in group B maintained their FBD in the first 6 months of treatment but, at the end of the study, showed a bone loss of 1.4% compared with basal values. By contrast, women in group C showed a significant increase in FBD after 1 year of treatment (+5.6%;p<0.01). Bothvalid completers andintention to treat analyses revealed a significant difference (p<0.05) between group A and group C over the study period. None of the treatments produced significant changes of biochemical markers of bone turnover, while hot flushes and other climacteric symptoms were significantly reduced after the sixth month of treatment in women receiving estrogens. Adverse events were generally mild, and did not differ among the groups. The results of this study suggest that low doses of estrogens combined with ipriflavone could represent a new therapeutic approach to the treatment of the postmenopausal syndrome.     

Giving up driving in Alzheimer's disease—an integrative therapeutic approach

For patients with Alzheimer's disease (AD), a recommendation to stop operating a motor vehicle can be a serious event complicated by a loss of self-esteem and personal dignity. Patients are often reluctant to give up an activity so essential, both practically and symbolically, to independent living. We describe here a patient with moderately progressed AD who lacked insight of his need to cease driving. Through an integrative treatment approach, combining behavioral and psychodynamic modalities, we helped him to formulate effective ways of coping with his loss of access to independent transportation. We favor a psychotherapeutic strategy that combines behavioral and managerial measures with dynamic patient interaction, thereby developing the patient's insight of the need to give up driving while fostering his sense of autonomy.     

神经降压素的肝细胞保护作用与Ca~（2＋）的关系

观察了神经降压素（ＮＴ）的肝细胞保护作用与Ｃａ２＋的关系。结果显示，醋氨酚使肝细胞Ｃａ２＋内流和肝脏钙含量增加，但对于线粒体Ｃａ２＋摄取及其钙含量无明显影响，表明细胞可能出现胞质Ｃａ２＋超载。若在醋氨酚之前给予ＮＴ则使肝细胞Ｃａ２＋内流明显减少，肝脏Ｃａ２＋含量有降低趋势，但线粒体钙含量显著增加。这些结果提示，ＮＴ通过减少Ｃａ２＋内流，增强线粒体贮存Ｃａ２＋的能力，部分缓解醋氨酚所致胞质Ｃａ２＋超载从而减轻细胞损伤。     

Flunarizine induces a transient loss of tyrosine hydroxylase immunoreactivity in nigrostriatal neurons

Neurotoxic effects of flunarizine (Fz), a selective calcium channel blocker, on the nigrostriatal dopamine system was investigated. Systemic injections of Fz to mice resulted in a transient loss of tyrosine hydroxylase (TH) immunoreactive nigrostriatal neurons without cell loss. TH immunoreactivity in these neurons was greatly reduced as rapidly as one day after drug administration (regardless of dosage used) and thereafter recovered in both dose- and time-dependent manners. Such a novel neurotoxic action of Fz may constitute a morphological substrate for reversible drug-induced parkinsonian signs described in recent clinical case reports.     

Stimulation of phagocytic function in mouse macrophages by neurotensin and neuromedin N

The neuropeptides neurotensin and neuromedin N (from 10⁻¹² M to 10⁻⁹ M) have been showed in this study to stimulate significantly in vitro several steps of the phagocytic process: adherence to substrate, chemotaxis, ingestion of inert particles (latex beads) and production of superoxide anion measured by nitroblue tetrazolium reduction in resting peritoneal macrophages from BALB/c mice. A dose-response relationship was observed, with a maximal stimulation of the phagocytic process at 10⁻¹¹ M. The two neuropeptides induced no change of intracellular cyclic AMP in murine macrophages. Moreover, adherence and chemotaxis decreased significantly in the presence of EGTA (1 mM), a chelator of extracellular Ca²⁺, or ryanodine (0.5 mM), a blocker of a Ca²⁺-gated channel from the endoplasmic reticulum, in both controls and samples with the addition of neurotensin or neuromedin N. These results suggest that there is no relation between the cAMP messenger system and the phagocytic process stimulation in murine peritoneal macrophages by neurotensin or neuromedin N. In addition, the results observed with EGTA and ryanodine could indicate that these two neuropeptides produce their effects through an increase of intracellular Ca²⁺ concentration.     

Sialic acid concentrations in the urine of men with and without renal stones

Summary It has been suggested that urinary sialidase may play a role in the formation of renal stones. The present study was therefore undertaken to compare spectrophotometrically the different types of sialic acid concentrations and sialidase activities in fresh first morning urine specimens of men (21–65 years) with (13) and without (9) calcium oxalate renal stones. Although the free urinary sialic acid concentrations of the two groups of men were statistically about the same (P=0.0614), the total (P=0.003) and bound (P=0.0012) urinary sialic acid concentrations differed significantly. Both the total and bound sialic acid concentrations were lower in the urine specimens of the stone patients than in their healthy counterparts. This decrease in urinary sialic acid concentrations was firstly thought to be the result of elevated breakdown enzymes of sialic acid, which would favour the production of pyruvate. However, spectrophotometric determinations of the endogenous pyruvate concentrations of the two types of urine specimens did not differ significantly (P=0.0708). Secondly, the decrease in total urinary total sialic acid concentration of stone patients, could be attributed to less sialic acid synthesis or less renal excretion. Therefore, the same experiments were repeated using serum of 13 patients and 9 healthy men. Conversely, the total (P=0.4425) and bound (P=0.2850) serum sialic acid concentrations were found to be similar in the two types of subjects. However, the free serum sialic acid concentration of stone patients was significantly lower than in the healthy subjects (P=0.0062). This phenomenon is also reflected in the average ratio for serum free: bound sialic acid in healthy and stone patients, 1:7.9 and 1:18.7 respectively (P=0.0009). The lower free serum sialic acid concentration may lead to lower renal excretions of sialic acid. This may explain the decrease in total urinary sialic acid concentration in stone patients. The lower bound urinary sialic acid concentrations in patients was also reflected in the urinary free: bound sialic acid ratio for healthy (1:2.3) and stone patients (1:1.3). The difference between these two groups of men was highly significant (P=0.0001). This phenomenon might be explained by the urinary sialidase activities, which was spectrophotometrically determined at 334 nm at 37°C of 11 patients with stones and 17 healthy men. The ages of both groups of men were the same (P=0.326). An increase in urinary sialidase activity was observed with the stone patients (P=0.00001) when compared to specimens of healthy men. This might explain the decrease in urinary bound sialic acid concentration of the stone group. It seems from these results that the urinary concentration of sialic acid and the activity of urinary sialidase, may play a role in the pathogenesis of the multifactorial disease, urolithiasis.     

自身免疫性感音神经性聋豚鼠的子代内耳生理功能研究

目的 :观察自身免疫性感音神经性聋 (ASHL)母豚鼠所产子代内耳生理功能的变化 ,探讨针对内耳的自身免疫因素对子代内耳生理功能的影响及其改变特点。方法 :同种内耳抗原 (CIEAg)持续免疫孕豚鼠 ,采用耳蜗电图 (记录cAP、CM )和眼震电图仪 (记录自发性眼震和冷热空气试验 )测试母鼠和子鼠的听觉和前庭功能 ,并检测血清特异性体液免疫反应。结果 :ASHL模型母豚鼠所产子鼠血清中发现有特异性抗体水平升高 ,部分 (3 /9)出现听觉损伤。非ASHL母鼠和对照组母鼠所产子代未见明显异常。结论 :ASHL雌鼠所产子代可出现感音神经性聋 ,其内耳损伤和功能障碍极可能与针对内耳组织的自身免疫反应 (尤其是体液免疫 )有关 ,从而提示内耳自身免疫因素可能为部分先天性非遗传性感音神经性聋的病因之一。