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.     

Periradicular healing in response to Diaket root-end filling material with and without tricalcium phosphate

The healing of the periradicular tissues was evaluated when the polyvinyl resin Diaket with and without tricalcium phosphate was used as surgical root-end filling material. Non-surgical root canal treatment was performed on 56 mandibular premolar roots in mongrel dogs. Following root-end resection, root-end cavity preparations were filled with Diaket, the comparative material, or Diaket in combination with tricalcium phosphate, the experimental material. Postsurgically, healing of the tissues adjacent to the filling materials and in the surrounding surgical site were evaluated at 30 and 60 days. There was virtually no statistically significant difference between the experimental and comparative group at or within the 30- or 60-day period with regard to inflammation, connective tissue formation, root-end encapsulation, cementum formation, or bone apposition. Findings suggest that cementogenesis occurred over both materials. The overall healing of the periradicular tissues was favourable.     

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.     

骨水泥和种植体同期植入修复颌骨和牙列缺损的实验研究

目的：探讨高分子材料和种植体同期植入缺损区进行同步骨缺损修复和牙列缺损修复的可行性。方法：以4只杂种狗为研究对象，制备下颌骨长约2．5cm的缺损的动物模型(保留下颌骨下缘)，将骨水泥(聚甲基丙烯酸酯)植入骨缺损，同时将牙种植体植入骨水泥中并调整长轴方向，立即关闭术创。至术后3个月摄X线片，然后处死动物，局部巨检以了解骨水泥同骨组织的结合情况，并制备骨组织切片进行苏木精一伊红染色和甲苯胺蓝染色，以了解植入材料周边骨的生长情况及其对植入材料的反应。结果：术后3个月X线检查见骨缺损区充满骨水泥，骨水泥周边的骨小梁清晰，未见骨吸收或炎症表现，形成良好的骨-骨水泥界面，种植体则依赖其表面的螺纹结构与骨水泥间紧密的机械性嵌合而牢固的成为一体，植入的骨水泥块与周边天然骨结合紧密，无松动现象。植入材料周边局部脱钙骨的苏木精-伊红染色和甲苯胺蓝染色见骨结构正常，同时骨-骨水泥界有新骨形成。结论：骨水泥作为颌骨修复替代材料同期植入种植体是可行的。     

经皮椎体成形术中骨水泥对老年骨质疏松症患者凝血功能的影响

目的 观察经皮椎体成形术(PVP)中骨水泥对老年骨质疏松症患者凝血功能的影响.方法 于椎弓根穿刺前10 min、注入骨水泥后1、20 min、2 h分别抽血检测11例患者的凝血功能相关指标,包括血浆凝血酶原时间(PT)、活化的部分凝血酶原时间(APTT)、血浆纤维蛋白原(FIB)和鱼精蛋白副凝固实验(3P实验),并汇总数据进行统计学分析.结果 PVP中骨水泥注入后20 min,PT缩短、FIB增高、3P实验阳性率升高(P<0.05),骨水泥注入2 h后基本恢复至注入前水平.除1例患者PTA术后2 h稍高于正常值(126%),其余患者各个时间点的各项指标均在正常参考值范围内.结论 PVP术中注入骨水泥对于凝血功能正常的患者基本安全,但在注入后会产生一过性轻微的高凝倾向.     

Micro-CT observation of rat dental pulp healing after pulpotomy in in vivo study

We report the newly developed Micro-CT, which allows us to observe the individual animal over a long experimental period and to compare changes in pulp tissue in relation to growth and aging without considering individual differences. Further, we used pathological examination to prove similar the result observing from Micro-CT. We have examined wound healing of teeth after pulpotomy in rats, and could clearly observe histopathological changes in the affected teeth and the absorption of temporary filling material and pulp capping agents. In cases with breakage of the dental crown, the CT images agreed with the pathological observations, and it was possible to estimate the time of breakage. In vivo Micro-CT is possible to apply in continuous recording of small experimental animals, such as rats, under anesthesia and the result is sufficiently high. High-quality image was obtained in of the entire head region of the rat. It was suggested that this method can be used for long-term continuous observation of changes in the teeth conditions after pulpotomy in experimental animals. We report the newly developed Micro-CT, which allows us to observe the individual animal over a long experimental period and to compare changes in pulp tissue in relation to growth and aging without considering individual differences.