骨胶原与骨质疏松骨密度及骨生物力学的相关性研究

目的探讨骨胶原含量在绝经后骨质疏松症的发生、发展及在骨质疏松性骨折中的作用。方法取7个月龄未交配雌性SD大鼠60只，随机分为四组，A组：对照组（sham组）；B组：切除卵巢组；C组：切除卵巢＋雌激素治疗组；D组：切除卵巢＋降钙素治疗组。除A组外，其他三组通过切除双侧卵巢法12周后制成骨质疏松模型，24周后分别行k的力学特性、右侧股骨三点弯曲试验、羟脯氨酸含量、k骨密度（BMD）测定，Masson三色染色法显示骨胶原形态。结果A、C、D组与B组在k羟脯氨酸含量、BMD、k压缩力学参数值、右侧股骨生物力学参数值、骨胶原染色含量及形态方面差异均有统计学意义（P〈0．05），而A、C、D组之间差异无统计学意义（P〉0．05）。统计学分析显示羟脯氨酸含量与BMD及骨生物力学参数值呈直线相关性。结论骨质疏松的发生与骨胶原含量下降有关。骨胶原含量的下降与BMD降低及骨生物力学改变呈相关性。应用雌激素和降钙素治疗去势后骨质疏松大鼠，不仅可以提高其BMD含量和骨生物力学性能，而且还可以提高骨胶原的含量。     

骨吸收抑制剂对卵巢切除骨折大鼠脂类代谢及骨钙素的影响

目的 研究骨吸收抑制剂对卵巢切除大鼠脂类代谢及骨钙素的影响.方法 雌性SD大鼠共140只,随机分为5组,每组28只.3月龄时选取其中4组大鼠行双侧卵巢切除建立绝经后骨质疏松症模型(OVX组、OVX+ EE2组、OVX+ Rlx组、OVX+ Aln组),另一组行假手术(Sham组).OVX组及Sham组皮下注射生理盐水,余下3组分别注射阿仑膦酸钠(Aln)、雷洛昔芬(Rlx)、雌激素(EE2),每周注射5次.分别在卵巢切除术后4周、10周及20周测定大鼠血脂、骨钙素及相关生化指标.结果 OVX组与Sham组相比体重增加,总胆固醇升高,甘油三脂降低,差异有统计学意义.应用雌激素及雷洛昔芬可有效调节卵巢切除导致的脂代谢紊乱,表现为体重下降及总胆固醇水平降低,差异有统计学意义(P＜0.05).不同时期OVX组骨钙素水平高于Sham组,差异有统计学意义(P＜0.05),其中阿仑膦酸钠组血清骨钙素水平最低.随着时间推移,Sham组及OVX组骨钙素呈现先上升再下降趋势,而OVX+EE2组、OVX+ Rlx组及OVX+ Aln组骨钙素表现为持续降低.结论 骨吸收抑制剂能够降低骨钙素水平,从而降低卵巢切除导致的高骨转换率,防止骨量丢失.此外,雌激素及雷洛昔芬在预防骨丢失的基础上还能够有效调节卵巢切除引起的脂类代谢紊乱.     

高脂饮食通过抑制Wnt/β-catenin信号介导对骨质疏松大鼠骨密度和骨修复的负面影响

目的 评估高脂饮食（HFD）对骨质疏松大鼠骨密度（bone mineral density, BMD)及骨修复的影响并探讨可能的机制。方法 将雌性SD大鼠随机分为三组：假手术卵巢切除组（Sham）、手术卵巢切除模型组（OVX）、手术卵巢切除模型+HFD（OVX+HFD）;随后所有大鼠在双侧去卵巢手术或假手术后12周基础上制作双侧股骨干建立骨缺损模型,OVX+HFD组大鼠在股骨上接受HFD干预4周。随后使用影像学、血清学、骨生物力学以及基因水平检测来评估骨修复效果。结果 与Sham组相比,OVX和OVX+HFD组的血清E2、ALP水平均显著降低( P<0.05),而TRAP水平均显著升高(P<0.05);OVX和OVX+HFD组之间有显著差异(P<0.05)。Micro-CT检测显示OVX+HFD组骨修复效果较OVX和Sham组明显降低;定量检测结果显示OVX+HFD组的BMD、Tb.N和Tb.Th显著小于OVX组(P<0.01),而Tb.Sp(P<0.05)在OVX+HFD组中明显大于在OVX组。生物力学显示HFD干预后明显降低了去卵巢大鼠骨缺损部位的机械强度,包括大鼠股骨的极限载荷、刚度、能量吸收和弹性模量(P均<0.05);基因检测表明与OVX组相比,OVX + HFD组Smad2、Smad3和GSK-3βmRNA表达显著增加(P<0.01),而Wnt1和β-cateninmRNA表达均显著降低(P<0.01)。结论 HFD对骨质疏松状态下骨缺损愈合有负面影响,而这种影响可能是通过对Wnt/β-catenin信号传导抑制来实现的。     

降钙素预防去势大鼠腰椎间盘退变的研究

[目的]观察降钙素对去卵巢大鼠腰椎骨量和椎间盘退变的作用。[方法]30只3个月龄Sprague-Dawley(SD)大鼠,随机均分为3组,每组10只:假手术(Sham)组,去卵巢(OVX)组,去卵巢+降钙素(OVX+CT)组。3个月后处死动物,并于处死前10d和4d分别给予四环素和钙黄绿素双荧光标记。取L2～4椎体进行骨密度及骨组织形态计量学分析,L4～5腰椎及椎间盘进行VG染色,运用免疫组化检测椎间盘MMP-13的表达,观察椎间盘的病理学改变并根据组织学评分系统对腰椎间盘的退变程度(LVD)进行评分。[结果](1)腰椎间盘评分:OVX+V组显著高于Sham组及OVX+CT组;(2)腰椎骨密度及骨形态计量学骨量参数(BV/TV,Tb.N):OVX+V组显著低于Sham组及OVX+CT组;(3)免疫组化:OVX+V组大鼠椎间盘中基质金属蛋白酶MMP-13表达显著高于OVX+CT组、Sham组。[结论]降钙素可预防去卵巢大鼠腰椎间盘的退变,其作用机制可能与维持椎体骨量及微观结构,同时降低椎间盘中MMP-13的表达抑制基质的降解有关。     

吡咯喹啉醌通过降低氧化应激和RANKL/OPG比率减少去卵巢大鼠骨量流失研究

目的观察补充吡咯喹啉醌(PQQ)对去卵巢诱导的骨质疏松大鼠骨量和骨强度的影响。方法 30只12周龄(225～260 g)雌性SD大鼠随机分为3组(每组n=10),即OVX组、OVX+PQQ组和Sham组;其中OVX组和OVX+PQQ组进行手术切除双侧卵巢,而Sham组进行假手术; OVX+PQQ组术后食物添加4 mg/kg PQQ。治疗12周,在治疗结束收集血液和股骨,分别进行微型计算机断层扫描(Micro-CT)、生物力学检测、组织切片检测、蛋白印迹检测(WB)以及血清指标检测。结果Micro-CT和HE切片表明,与Sham组相比,OVX组的股骨骨密度和骨微观参数显著降低(P0.05); OVX组的小梁间距显著增加(P0.05),而OVX+PQQ上述指标明显优于OVX组(P0.05)。生物力学检测表明Sham组具有最高的极限载荷、能量和刚度;与OVX组比较,OVX+PQQ组极限载荷、能量和刚度明显增加(P0.05)。血清学表明,与Sham组大鼠相比,OVX大鼠血清CTX-1、TRACP-5b和MDA水平均显著升高,而T-AOC和SOD活性显著降低; PQQ治疗后显著改善(P0.05)。WB检测结果表明与Sham组大鼠相比,OVX大鼠RANKL和RANKL/OPG比率均显著升高,而OPG和FOXO1表达显著降低;经过PQQ后得到RANKL和RANKL/OPG比率均显著降低,而OPG和FOXO1表达显著增加(P 0.05)。结论 PQQ通过抑制氧化应激和降低RANKL/OPG比率来增加去卵巢大鼠骨量和骨强度。     

微弧氧化处理的内植物在骨质疏松兔中的生物学表现

[目的]观察经过微弧氧化(micro-arc oxidation,MAO)表面处理的内植物是否能提高其在骨质疏松兔体内生物学表现.[方法]选用30只成年雌性新西兰大白兔,随机分为卵巢切除组(ovx组,n=20)和假手术组(Sham组,n=10),手术后2周,Ovx组接受甲泼尼龙注射,Sham组接受生理盐水注射,6周后分别行双能X线检测两组的骨密度(bone mineral density,BMD).确定Ovx组骨质疏松模型建立成功后,兔胫骨两侧随机置入经MAO处理的及未处理的内植物,处理组为实验组,未处理组为对照组,术后12周处死动物,取材标本进行生物力学实验,显微CT检测以及组织学分析.[结果]OVX组的BMD显著低于Sham组(P<0.05).内植物置入OVX组12周后,实验组的最大拔出力,能量吸收值,骨体积和组织骨密度,新骨形成率和骨接触率均优于对照组(P<0.05).[结论]微弧氧化处理能够提高内植物在骨质疏松条件下的生物学表现,有利于增强内植物的稳定性.     

软骨下骨注射常山酮对大鼠卵巢切除后骨性关节炎的影响

[目的]探讨常山酮软骨下骨给药方法对原发性骨性关节炎(OA)模型发病进展的影响,以及可能的机制。[方法] 6月龄SD雌性大鼠30只,随机分为3组,10只仅给予假手术处理(Sham组);10只行双侧卵巢切除(ovariectomy, OVX),并软骨下注入不含常山酮的溶媒(vehicle+OVX组);10只行OVX后,软骨下给予常山酮(halofuginone, HF)。采用免疫荧光、免疫组化染色等检测软骨下骨骨显微结构及关节软骨相关蛋白变化,并行micro-CT形态观察。[结果]与Sham相比,OVX后大鼠关节软骨Ⅱ型胶原减少,OARSI评分、破骨细胞TARP和Smad2/3表达增加,Sham组与vehicle+OVX组间差异有统计学意义(P0.05),但与HF+OVX组间差异无统计学意义(P0.05)。micro-CT形态测量方面:OVX后Tb.Pf显著增加,而BV/TV、SBP.Th和Tb.N显著下降,Sham组与vehicle+OVX组间差异有统计学意义(P0.05),但与HF+OVX组间差异无统计学意义(P0.05)。[结论]通过软骨下骨给药常山酮可延缓OA进展,这可能与其抑制软骨下骨异常TGF-β信号有关。     

前交叉韧带切断对卵巢切除大鼠股骨骨折愈合的影响

目的观察前交叉韧带切断(OA动物模型)对双侧卵巢切除大鼠(OVX绝经后骨质疏松模型)股骨骨折愈合的影响。方法12周龄SD大鼠共70只，分成基础对照组(Basal)、假手术组(Sham)、双侧卵巢切除术组(OVX)、卵巢切除 前交叉韧带切断术组(OVX OA)、假手术 骨折组(Sham F)、卵巢切除术 骨折组(OVX F)、卵巢切除 前交叉韧带切断 骨折组(OA OVX F)，每组10只大鼠。所有受试大鼠在处死前第10d天和第4d天分别皮下注射盐酸四环素和钙黄绿素行双荧光标记。基础对照组在实验开始时杀死，其余6组在术后6W杀死，取大鼠右侧股骨标本。然后，分别进行CR摄片、组织形态学染色，以及应用Norland-XR36双能X线骨密度仪(DXA)测量右股骨远段骨密度和中段骨密度，并将股骨远段及骨折段骨痂进行硬组织包埋、切片，作骨组织形态计量学测量。结果①OVX OA组与OVX组比较，股骨远段。BMD和BWTV显著增加；②OVX F组与Sham F组比较，骨痂(股骨中段)BMD和BV／TV显著降低：③OVX OA F组与OVX F组比较，骨痂(股骨中段)BMD利BV／TV无统计学差异。结论①骨质疏松不仅延缓骨折愈合过程，而且降低骨折愈合质量；②在此动物模型中，骨性关节炎延缓股骨骨质疏松的发生，但是，对骨质疏松性骨折的愈合没有确切的促进作用。     

辅酶Q10对去卵巢大鼠股骨显微结构及生物力学的影响

目的应用骨生物力学和micro-ct技术,探讨Co Q10对去卵巢大鼠的股骨显微结构及生物力学的影响。方法 48只3月龄SPF级SD雌性未孕大鼠,随机分为假手术组(Sham)、去卵巢模型组(OVX)、小麦胚芽油组(WGO)、WGO+辅酶Q10组(高、低剂量)、戊酸雌二醇组(EV),连续给药90d。实验结束后,取右侧股骨进行生物力学检测,然后进行Micro CT扫描及三维重建。结果与Sham组比较,OVX组大鼠股骨的微观参数:骨体积分数、骨小梁数量、骨小梁厚度和骨密度明显减少,骨小梁分离度和结构模型指数明显增高;而股骨的骨生物力学参数:最大载荷、断裂载荷及弹性载荷明显减少,刚度明显减少。与OVX组相比,EV组大鼠股骨的骨微观参数均得到了良好地修复,骨生物力学参数中最大载荷、断裂载荷、弹性载荷及刚度得到了明显修复。而小麦胚芽油+低剂量CoQ10组大鼠股骨的微观参数骨小梁数量、骨小梁分离度、结构模型指数及骨密度和骨体积分数则得到一定程度的修复。结论辅酶Q10(15 mg/kg)能够修复OVX大鼠股骨微观结构破坏,辅酶Q10(15 mg/kg)可以预防去卵巢手术导致大鼠股骨松质骨结构破坏和股骨生物力学性能的下降,其他剂量组对此无明显的预防作用。提示辅酶Q10的抗骨质疏松作用具有良好的研究前景。     

卵巢切除大鼠在不同时期RANKL、OPG蛋白表达的变化及与BTMs的相关性

目的探讨卵巢切除大鼠在不同时期骨保护素(OPG)、核因子κB受体活化因子配体(RANKL)的表达及与骨转换标志物(BTMs)的关系。方法将SD雌性大鼠随机分成假手术组(Sham)和去卵巢骨质疏松模型组(OVX),模型组行双侧卵巢切除术,术后第2、6、10、14周分批取材,采用Western blot检测各时期大鼠骨组织OPG、RANKL蛋白表达,采用Elisa检测各时期大鼠血清骨转换标志物BGP、BALP、CTX-I、TRAP-5b的变化。结果 OVX组在术后第2周(P0.01)和第10、14周(P0.05)骨组织RANKL蛋白表达均较Sham组显著升高,OPG蛋白表达在第2周(P0.01)和第6周(P0.05)均显著降低。(2)与Sham组相比,OVX组术后第2周血清BGP、BALP、CTX-I(P0.05)和TRAP-5b(P0.01)水平均显著升高;OVX组术后第6周血清BGP、BALP水平显著升高(P0.01),CTX-I(P0.05)和TRAP-5b(P0.01)水平显著下降;OVX组术后第10、14周血清CTX-I(P0.05)、BALP(P0.01)水平显著升高。(3)骨转换标志物血清CTX-I、TRAP-5b水平与骨OPG表达成负相关(P0.01),与骨RANKL表达成正相关(P0.05)。结论相关性分析显示骨转换标志物CTX-I、TRAP-5b与骨OPG成负相关,与骨RANKL成正相关。     

Histochemical and contractile properties of striated muscles of urethra and levator ani of dogs and sheep

AIMS: To understand their possible importance in long- and short-term control of continence, some properties of the striated muscles of the urethra and pelvic floor (levator ani) of dogs and sheep were investigated, especially fiber types and contractile characteristics. MATERIALS AND METHODS: Striated muscles of urethra and levator ani of 29 male and 6 female dogs and 11 male and 6 female sheep were removed and cut into strips. Some strips were frozen and stained for ATPase at pH 9.4 and 4.3 for fiber typing; others were set up in an organ bath to study contractile responses to nerve stimulation. RESULTS: All muscles contained both type I (slow) and type II fibers, ranging from 97% type II in female greyhound urethra to 60% in female sheep levator ani. For each muscle, there were fewer type II muscles in sheep than in dog. The diameters of the urethral fibers were about 60% of the levator ani in dogs and 34% in sheep. Contraction of the urethral muscle was faster than for levator ani and declined to about 80% of the peak, 500 msec after the beginning of stimulation at 20 Hz. The levator ani contraction rose to a steady level as long as stimulation continued. CONCLUSIONS: Both the levator ani and urethral striated muscles contain slow and fast fiber types. The levator ani muscles are capable of sustained contraction with rapid onset which will produce long-term closure of the urethra. The circular urethral muscle contraction was faster but less well maintained.     

Instrumented ligamentotaxis and stabilization of compression and burst fractures of dorsolumbar and mid-lumbar spines

Background:

Controversy continues regarding the best treatment for compression and burst fractures. The axial distraction reduction utilizing the technique employing the long straight rod or curved short rod without derotation to reduce fracture are practised together with short segment posterolateral fusion (PLF). Effects of the early postoperative mobilization without posterolateral fusion on reduction maintenance and fracture consolidation were not evaluated so far. The present prospective study is designed to assess the effectiveness of i) reduction and restoration of sagittal alignment, ii) no posterolateral fusion on the reduced, fractured vertebral body and injured disc, iii) fracture consolidation and iv) the fate of the unfused cephalad and caudal injured motion segments of the fractured vertebra.

Materials and Methods:

The study includes 15 Denis burst and two Denis type D compression fractures between T₁₂ and L₃. The lordotic distraction technique was used for ligamentotaxis utilizing the contoured short rods and pedicle screw fixator. Three vertebrae including the fractured one were fixed. The patients after surgery were braced for ten weeks with activity restriction for 2-4 weeks. The patients were evaluated for change in vertebral body height, sagittal curve, reduction of retropulsion, improvement in neural deficit. The unfused motion segments, residual postoperative pain and bone and metal failure were also evaluated.

Results:

The preoperative and postreduction percentile vertebral heights at, zero (immediate postoperative), at three, six and 12 months followup were 62.4, 94.8, 94.6, 94.5 and 94.5%, respectively. The percentages of the intracanal fragment retropulsion at preoperative, and postoperative at zero, 3, 6 and 12 months followup were 59.0, 36.2,, 36.0, 32.3, and 13.6% respectively.The preoperative and postreduction percentile loss of the canal dimension and at zero, three, six and 12 months were 52.1, 45.0, 44.0, 41.0 and 29% respectively suggesting that the under-reduced fragment was being resorbed gradually by a remodeling process. The mean initial kyphosis of 33° became mean 2° immediately after reduction and mean 3° at the final followup. The fractured vertebral bodies consolidated in an average period of ten weeks (range 8-14 weeks). The restored disc heights were relatively well maintained throughout the observation period. All paraparetic patients recovered neurologically. There were no postoperative complications.

Conclusion:

Instrument-aided ligamentotaxis for compression and burst fractures utilizing the short contoured rod derotation technique and the instrumented stabilization of the fractured spine are found to be effective procedures which contribute to the fractured vertebral body consolidation without recollapse and maintain the motion segment function.     

Recognition and management of phaeochromocytoma and paraganglioma

Phaeochromocytomas and paragangliomas (PPGL) are catecholamine-secreting neuroendocrine tumours arising from the chromaffin cells in the adrenal medulla. These tumours may be identified incidentally, as part of a work-up for multiple endocrine neoplasia or following haemodynamic surges during unrelated procedures. Advances in perioperative management and improved management of intraoperative haemodynamic instability have significantly reduced surgical mortality from around 40% to less than 3%. Surgery is the definitive treatment in most cases and laparoscopic resection where possible is associated with improved outcomes. Anaesthetic management of PPGL cases represents a unique haemodynamic challenge both before and after tumour resection. In this article we describe the physiology of these tumours, their diagnosis, preoperative optimization methods, intraoperative anaesthetic management and management of postoperative complications.     

Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist and nabilone, a synthetic cannabinoid.     

Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist, and nabilone, a synthetic cannabinoid.     

Incorporation and release of85Sr and14C-proline-hydroxyproline in mineral and collagen of bone and incisor teeth of growing rats

The extent to which exchange and reutilization processes of mineral tracers affect skeletal mineral accretion and resorption measurements was evaluated by comparing the rates of appearance and disappearance of⁸⁵Sr and¹⁴C-proline-hydroxyproline in bones and teeth in growing rats for 12 days following simultaneous parenteral injection of these tracers. Expressions for the relative rates of collagen synthesis and breakdown, which unlike mineral metabolism are considered not to be complicated by exchange phenomena, were based on¹⁴C-proline conversion to¹⁴C-hydroxyproline; the specific activity of the latter was determined. Both the mineral and the collagen specific activities reflected the rates and patterns of growth of the samples assayed; rapid growth and a short interval of time between formation and resorption of tissue in themetaphyseal bone which contains the cartilagineous growth plate, slow growth and an interval of time between formation and resorption of tissue indiaphyseal bone and incisor teeth which is longer than the 12 days of the experiment. However, in metaphyseal bone the specific activity collagen/mineral ratio dropped by one half during the 4–12 day interval in contrast to diaphyseal bone and incisor teeth in which no change in this ratio was observed during this period of time. The data indicate that collagen in the metaphyseal growth zone is removed by resorption before it has become fully mineralized, and that exchange is a relatively unimportant factor in the long term kinetics of bone mineral.

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Zusammenfassung Das Ausmaß, bis zu welchem Austausch- und Wiederverwendungsprozesse der mineralen Tracer die Messungen des mineralen Skelett-Auf- und Abbaues beeinflussen können, wurde ausgewertet; zu diesem Zweck wurde die Geschwindigkeit des Auftretens und Verschwindens von⁸⁵Sr und von¹⁴C-Prolin-Hydroxyprolin in Knochen und Zähnen von wachsenden Ratten während der 12 auf die simultane parenterale Injektion dieser Tracer folgenden Tage verglichen.Der Ausdruck für die relative Geschwindigkeit des Kollagen-Auf- und Abbaues, bei welchem im Gegensatz zum Mineralmetabolismus kein Mitwirken des Austauschphänomens vermutet wird, basiert auf der Umwandlung von¹⁴C-Prolin zu¹⁴C-Hydroxyprolin; die spezifische Aktivität des letzteren wurde bestimmt.Aus der spezifischen Aktivität des Minerals sowie jener des Kollagens konnten die Geschwindigkeit und die Art des Wachstums der untersuchten Proben ersehen werden, d.h.schnelles Wachstum und ein kurzes Zeitintervall zwischen Bildung und Resorption des Gewebes imKnochen der Metaphyse, die auch die knorpelige Wachstumsplatte enthält, und andererseitslangsames Wachstum und längeres Zeitintervall (länger als die 12 Tage des Experimentes) zwischen Bildung und Resorption des Gewebes imKnochen der Diaphyse und in den Schneidezähnen. Immerhin fiel die spezifische Aktivität des Kollagen/Mineral-Anteils im Knochen der Metaphyse während dem 4–12tägigen Zeitintervall auf die Hälfte, im Gegensatz zum Knochen der Diaphyse und der Schneidezähne, bei welchen während dieser Zeitspanne kein Unterschied in diesem Verhältnis beobachtet wurde.Diese Ergebnisse zeigen, daß Kollagen in der Wachstumszone der Metaphyse durch Resorption verschwindet, bevor es ganz mineralisiert ist, und daß der Austausch ein relativ unwichtiger Faktor in der Kinetik auf lange Sicht des Knochenminerals ist.

     

动静脉穿刺网络课件的开发及其应用

目的:确保护理教学效果,提高教学水平。方法:应用多项信息技术将动静脉穿刺技术制作成教学网络课件,并用于临床教学。结果:该课件在本校园网上运行半年余,2000余人次对其进行访问,受到师生好评。结论:该课件能及时反映动静脉穿刺的最新研究进展及具体操作步骤和使用方法,实现护理教学的直观性和交互性,对护理教学和临床带教指导有一定的借鉴作用。     

Physiology and pharmacology of nausea and vomiting

The physiology of nausea and vomiting is poorly understood. The initiation of vomiting varies and may be due to motion, pregnancy, chemotherapy, gastric irritation or postoperative causes. Once initiated, vomiting occurs in two stages, retching and expulsion. The muscles responsible for this sequence of events are controlled by either a vomiting centre or a central pattern generator, probably in the area postrema and the nearby nucleus tractus solitarius. Drugs which induce vomiting include ipecacuanha, a gastric irritant, and apomorphine, a dopamine-receptor agonist. Opioid drugs also induce vomiting, but opioid antagonists are not useful to treat nausea and vomiting. Anti-emetic drugs consist of a variety of neurotransmitter antagonists and may act in the periphery, the central nervous system or both sites. The most important drugs are antagonists at muscarinic, dopamine D₂, 5-HT₃, histamine H₁ and neurokinin NK₁ receptors. These drugs are discussed with particular attention to post-operative nausea and vomiting (PONV).