The experimental study on mixed culture of osteoblasts and tricalcium phosphate ceramicsin vitro

Summary To study the effects of tricalcium phosphate (TCP) ceramics on osteoblasts, the rat osteoblasts were cultured with the TCP ceramicsin vitro. Scanning electron microscopy and the colorimetric methyl-thiazol-tetrazolium assay showed that the osteoblasts could adhere well to the surface of the ceramics and the culture dish, and the proliferation of the cells was not inhibited. The results demonstrated that TCP ceramics possessed an excellent cytocompatibility with the osteoblasts, and had some promoting effects on proliferation of osteoblasts. This project was supported by grant from the National Natural Science Foundation of China (No. 59493202).     

胆囊结石患者胆固醇酯转移蛋白基因多态性研究

为揭示胆囊结石病与遗传因素的关系,运用聚合酶链反应技术（ＰＣＲ）和基因限制性片段长度多态性分析法（ＲＦＬＰｓ）对１０４例胆囊结石患者和６８例健康人进行了研究。结果显示：胆囊结石组Ｂ１等位基因频率５２．３％,Ｂ１Ｂ１基因型频率２８．８％,大于对照组Ｂ１等位基因频率３４．６％（Ｐ＜０．０５）,Ｂ１Ｂ１基因型频率１１．７６％（Ｐ＜０．０５）,胆囊结石组Ｂ２等位基因频率４７．７％,Ｂ２Ｂ２基因型频率２４．２％小于对照组Ｂ２等位基因频率６５．４％（Ｐ＜０．０５）,Ｂ２Ｂ２基因型频率４２．６％（Ｐ＜０．０５）。胆囊结石组Ｈ１等位基因频率２０％,Ｈ１Ｈ１基因型频率５％,Ｈ２Ｈ２基因型频率６５％,Ｈ２等位基因频率８０％与对照组Ｈ１等位基因频率１７．９％,Ｈ１Ｈ１基因型频率２％,Ｈ２Ｈ２基因型频率６５．９％,Ｈ２等位基因频率８２．１％比较无显著性差异（Ｐ＞０．０５）。提示：Ｂ１等位基因是胆囊结石患者主导基因。Ｂ２等位基因是对照组的主导基因。Ｈ１及Ｈ２等位基因频率在胆囊结石患者及对照组中分布相同,无显著性差异（Ｐ＞０．０５）。     

Cerebral metabolic profile, selective neuron loss, and survival of acute and chronic hyperglycemic rats following cardiac arrest and resuscitation

Cortical metabolites and regional cerebral intracellular pH (pHi) were measured in normoglycemic (NM), acute hyperglycemic (AH), and chronic hyperglycemic (CH, 2 week duration, streptozotocin-induced) Wistar rat brains during cardiac arrest and resuscitation. During total ischemia in AH and CH rats (plasma glucose approximately 30 mM), cortical ATP, PCr, glucose, and glycogen all fell significantly as expected. Lactate levels increased dramatically in association with a concomitant intracellular acidosis. Although lactate reached higher concentrations in AH and CH than NM, pHi was significantly lower only in the AH group. With 5 min of reperfusion, all groups recovered to near baseline in all variables, though lactate remained elevated. In a separate aspect of the study, animals from each experimental group were allowed to recover for 4 days following resuscitation, with outcome being gauged by mortality rate and hippocampal CA1 neuron counts. NM survival rate was significantly better than AH and CH. In particular, no CH rats survived for 4 days despite rapid initial recovery. After 4 days, the AH group had suffered significantly greater CA1 neuron loss than the NM rats. In summary, our research identified differences in intra-ischemic acid-base status in the two hyperglycemic groups, suggesting that chronic hyperglycemia may alter the brain's buffering capacity. These observations may account for differences between acutely and chronically hyperglycemic subjects regarding outcome, and they suggest that factors other than hydrogen ion production during ischemia are responsible for modulating outcome.     

Crystallization in the nephron

Recent experimental studies on the crystallization of calcium salts at different nephron levels support the theory that the initial formation of calcium concrements starts with an intratubular crystallization of calcium phosphate (CaP) and calcium oxalate (CaOx). CaP seems to be the initial crystallization product in pure CaP and mixed calcium phosphate–calcium oxalate (CaPCaOx) concrements, with the formation of CaP crystals at a nephron level above the collecting duct. Urinary macromolecules and cellular degradation products most probably promote this process. During the passage through the collecting duct, CaP might partly or completely dissolve at the lower pH encountered there. This might result in an increased concentration of calcium and hence an increased supersaturation with CaOx, which in turn can bring about a heterogeneous nucleation of CaOx on or around preformed CaP crystals or crystal aggregates. The final result will be mixed CaOxCaP or pure CaOx concrements. Pure CaOx concrements might also be the result of an initial CaOx crystallization at nephron levels above or in the collecting duct under conditions with a high urinary excretion of oxalate. Whether intratubular crystallization of calcium salts results in the formation of small harmless crystals excreted with urine or calcium stones appears to be determined by a complex process, involving kinetic factors that influence crystal growth and crystal aggregation and crystal retention. Received: 24 December 1998 / Accepted: 11 March 1999     

Crystallization during volume reduction of solutions with a composition corresponding to that in the collecting duct: the influence of hydroxyapatite seed crystals and urinary macromolecules

To examine the effect of hydroxyapatite (HAP) seed crystals and urinary macromolecules on the crystallization under conditions similar to those in the collecting duct, we evaporated 100 ml samples of salt solutions with an ion composition assumed to correspond to that in the collecting duct without and with HAP seed crystals. The crystallization in seeded solutions was assessed both with and without dialysed urine (dU). After evaporation the number and volume of crystals were recorded in a Coulter Multisizer and the crystal morphology examined with scanning electron microscopy (SEM) and X-ray crystallography. Addition of HAP crystals was apparently followed by an approximately 15–20% increase in heterogeneous nucleation of calcium oxalate (CaOx). In these experiments SEM and X-ray crystallography showed a high percentage of CaOx in the precipitate. In samples reduced to 40–69 ml, addition of dU to the collecting duct solution containing HAP seed resulted in a greater mean (SD) number of crystals; 3895 (1841) in samples with dU and 1785 (583) in samples without. This was mainly explained by an increased mean (SD) number of small crystals. The mean crystal volume was 17.8 (1.1) and 34.3 (9.1) in samples reduced to 40–69 ml with and without dU, respectively. This might reflect the inhibitory effect of dU on the growth and/or aggregation of the CaOx-CaP precipitate or a promoted nucleation resulting in a large number of small crystals. It is concluded that calcium phosphate formed above the collecting duct might induce heterogeneous nucleation of CaOx at lower levels of the renal collecting system, and that urinary macromolecules are powerful modifiers of these processes. Received: 8 July 1998 / Accepted: 12 March 1999     

N-nitro- -arginine methylester is protective against ethanol-induced gastric damage in cholestatic rats

In this study the effect of nitric oxide (NO) synthesis inhibition on ethanol-induced gastric damage was evaluated in bile duct-ligated, sham-operated and unoperated rats. The animals were injected intraperitoneally with saline, -arginine (200 mg/kg) or N^G-nitro- -arginine methylester ( -NAME) in doses of 5, 15 and 30 mg/kg, 30 min before ethanol administration. The animals were killed 1 h after ethanol administration and their stomachs were removed for measurement of gastric mucosal damage. The results showed that -NAME significantly enhanced the development of gastric mucosal lesions in sham-operated and unoperated rats, while in bile duct-ligated animals, -NAME decreased and -arginine enhanced the potentiation of ethanol-induced gastric mucosal damage. The plasma level of nitrite and nitrate was also measured and was significantly higher in bile duct-ligated rats than in control groups. The results suggest that inhibition of NO synthase with -NAME has different effects on ethanol-induced gastric damage in cholestatic groups and in normal rats and that these effects can be explained by overproduction of NO in bile duct-ligated animals.     

反相高效液相色谱法测定阿司匹林可待因片中磷酸可待因和阿司匹林的含量

目的：建立一种用高效液相色谱法检测复方制剂中磷酸可待因和阿司匹林含量的方法。方法：用Ｃ１８ＯＤＳ为固定相。甲醇－００３ｍｏｌ·Ｌ－１醋酸钠（用冰醋酸调ｐＨ至３５）（１∶２５）为流动相。ＵＶ检测波长２８０ｎｍ。结果：该方法回收率为磷酸可待因１００４％,ＲＳＤ＝１３％（ｎ＝６）;阿司匹林９９４％,ＲＳＤ＝０９８％（ｎ＝６）。结论：该法不需经提取分离,溶解后直接进样。简便、快速,准确可靠,适合于生产中使用。     

Additive effect of nitric oxide and prostaglandin-E2 synthesis inhibitors in endotoxin-induced uveitis in the rabbit

The involvement of nitric oxide (NO) and prostaglandin E₂ (PGE₂) was investigated in a model of intraocular inflammation induced by intravitreal injection of endotoxin (lipopolysaccharide, LPS, 10 ng) in rabbits. The severity of uveitis, the myeloperoxidase (MPO) activity in iris-ciliary body, and the protein concentration in aqueous humor were determined. Nitric oxide synthase (NOS) and cyclooxygenase (COX) activities were assessed respectively by nitrite and PGE₂ levels in aqueous humor. Treatment with inhibitors of NOS (N^G-nitro-L-arginine methyl ester, L-NAME, 50 mg/kg i.p.) or COX (diclofenac, 30 g, topically), alone or in combination, were compared to a salinetreated group. Diclofenac or L-NAME alone reduced or delayed the intensity of uveitis, and partially decreased the protein concentration in aqueous humor; diclofenac, but not L-NAME, partially reduced the polymorphonuclear leukocyte infiltration in the iris ciliary body as indicated by the MPO activity. Treatment with both inhibitors in combination diminished the clinical uveitis, the disruption of the blood-aqueous barrier and the MPO activity in the iris-ciliary body. We conclude that NO and PGE₂ have additive effects in endotoxin-induced uveitis in rabbits, and that the inhibition of both pathways would improve the therapeutical management of uveitis.accepted by M. J. Parnham     

Phospholipase D in heart: basal activity and stimulation by phorbol esters and aluminum fluoride

Summary Evidence for a general role of phospholipase D in signal transduction is accumulating. In the present study, the activity of the enzyme was investigated in heart tissue under basal conditions and after addition of phorbol esters or aluminum fluoride (AlF _inf4 ^sup– ; 10 mM NaF plus 10 M AlCl₃). Atria of rats and chickens were incubated with [³H]-myristic acid in order to label preferentially phosphatidylcholine. Under basal conditions, the tissues generated choline and phosphatidic acid (PtdOH), the primary catalytic products of phospholipase D. When 0.5 or 2.0% ethanol was present, [³H]-phosphatidyl-ethanol (PETH) was rapidly formed at the expense of [³H]-PtdOH. This transphosphatidylation reaction is specific for phospholipase D activity. The basal formation of PETH was not inhibited by a Ca²⁺-free, EGTA-containing medium. - The phorbol ester 4-phorbol-12,13-dibutyrate (PDB), which is known to activate protein kinase C, enhanced the net formation of choline, whereas the inactive 4-phorbol-13-acetate (PAc) was ineffective. PDB (0.2 M), in contrast to PAc, also increased the formation of [³H]-PtdOH and, in the presence of ethanol, of [³H]-PETH. The PDB-evoked formation of PETH occurred again at the expense of PtdOH. Treshold and maximum effective concentrations of PDB were 10 nM and 0.2–0.6 M, respectively. The effects of PDB on either choline efflux and generation of PETH showed the same Ca^t+-dependency, i.e., both effects were blocked by a Ca²⁺-free, EGTA-containing medium, but not by a Ca²⁺-free medium without EGTA. In protein kinase C-deficient tissue which was prepared by pretreatment with 0.61 M PDB for 27 h, PDB failed to enhance the formation of PtdOH and PETH. - A1F4–, a known activator of G-proteins, increased not only the tissue content of inositol phosphates, but also markedly enhanced choline efflux and formation of [³H]-PtdOH and PETH. In conclusion, in mammalian and avian atria a high phospholipase D activity was found even under basal conditions. The enzyme was stimulated by protein kinase C and presumably by a G protein.Abbreviations IP inositol phosphate - DAG diacylglycerol - PL phospholipase - PtdOH phosphatidic acid - PETH phosphatidylethanol - PDB 4-phorbol-12,13-dibutyrate - PAc 4-phorbol-13-acetate - AlF _inf4 ^sup– aluminum fluoride - DMSO dimethylsulfoxide Correspondence to K. Löffelholz at the above address