上颌第一前磨牙的根管解剖

目的：分析上颌第一前磨牙根管形态。方法：对200颗上颌第一前磨牙进行透明牙标本制作。结果：显示6种根管分型。结论：上颌第一前磨牙根管系统复杂,熟悉其根管解剖具有重要的临床意义。     

陶然亭社区患者根管治疗失败原因的临床分析

目的：分析探讨根管治疗失败原因可进一步提高根管治疗成功率。方法：按纳入标准选取126颗根管治疗失败的患牙．根据病例资料．记录临床表现和X线检查。总结分析治疗失败和根管充填程度,牙冠修复,151腔宣教等的关系。结果：126颗患牙中,根尖有病变的患牙最多,106颗,占84．13％;其次,是根管充填不严密102颗,占80．95％,其中,欠充占多数,为75颗患牙,超充为少数27颗患牙;第三,是冠渗漏52颗患牙,占41．27％,其中修复体缺损29颗,继发龋15颗,修复体脱落8颗;第四,为未及时复诊病例23颗,占18．25％;第五,为牙折的病例10颗,占7．94％;第六,为遗漏根管8颗,占6．35％。有些患牙会同时出现上述1-4种情况。结论：根管治疗失败的主要原因是根尖有病变,根管充填欠佳,冠渗漏,遗漏根管,未及时复诊,口腔宣教不到位等。     

一种根管充填剂的应用观察

根管充填是牙体疾病在治疗中不可缺少一个步骤，其充填材料有不少报道和研究，我科自1995年以来采用替硝唑、碘仿与丁香油调成糊剂，进行根管充填，效果较好。1．一般资料：自1995年2月至1996年6月，对确诊为根尖炎牙齿，60例，60个牙，其中男35例（40个牙），女15例（20个牙），前牙10个，前磨牙15个，磨牙35个，年龄最大65岁，最小18岁，经根管治疗后，根尖周症状消失，格管内棉论干燥，无渗出液及臭味，按常现根管充填方法进行充填。2．疗效判断；成功：患牙经充填后能行使咀嚼功能，无叩痛，无瘘管，X线片对照，可见根尖周骨质稀疏区缩…     

根管充填材料的根端微渗漏实验研究

目的：实验旨在评价4种牙齿根管充填材料对根尖孔的封闭性能。方法：将离体人牙48颗（均为单根），随机分为4组，每组12颗牙齿。分别充填ZOE、RF、HA、VITAPEX4种材料至距根尖孔0．5mm处，用染料渗入法在显微镜下观测染料渗入距离，结果：微渗漏值比较由小到大值为VITAPEX、ZOE、RF、HA，结论：通过微渗漏值的比较，说明VITZPEX封闭根尖孔能力显著优于其它3种材料，其后依次为ZOE、RF、HA。     

玻璃纤维桩在单根管第二前磨牙牙体缺损修复中的临床观察

目的：探讨玻璃纤维桩在单根管前磨牙牙体缺损修复治疗中的临床效果。方法：临床选择80例单根管前磨牙牙体缺损的患者,104颗患牙。经完善的根管治疗后,根据牙根的情况,选择玻璃纤维桩的直径和长度,再以全冠修复,并经过2年临床疗效的追踪观察。结果：104颗患牙有100颗无异常,4颗有不同程度的脱落和龈炎,修复成功率为96.15%,修复效果满意。结论：玻璃纤维桩在单根管前磨牙牙体缺损的修复治疗中,能达到良好的修复效果。     

上颌第一恒磨牙根管形态的透明牙观察

目的:运用透明技术研究上颌第一恒磨牙根管形态。方法:收集离体上颌第一恒磨牙90颗保存在10%的福尔马林液中,将离体牙制作成透明标本,按Vertucci的标准对根管分类并记录根尖孔数目。结果:上颌第一恒磨牙均为三根牙。所有的腭根及绝大多数的远颊根(97.78%)为单根管。近颊根单根管率为22.22%,双根管率为73.34%,三根管率为4.44%,以Ⅱ型和Ⅳ型根管最为普遍。管间侧支在近颊根多见,侧支根管多见于根尖1/3。结论:上颌第一恒磨牙近颊根多根管率较高(77.78%),掌握其解剖形态对提高根管治疗成功率具有重要的临床意义。     

双侧上颌第一前磨牙三牙根三根管1例报告

<正>上颌第一前磨牙牙根变异较为复杂,多为扁根,约占75%,双根通常在根尖1/3或1/2处分为颊、腭两个较细的根,约占23.13%,而三根的发生率约为1.87%,分为颊侧近中、远中细而弯曲的二根和一个较为粗而直的腭根,三根临床上比较罕见^[1]。上颌第一前磨牙根管解剖变异也较为复杂^[2],各型分类中,14.7%为一个根管,85.1%为复杂的两根管类型,又可分2-1,1-2-1,2-2,1-2,2-1-2等亚型,三根管仅有0.2%。现报告1例双侧上颌第一前磨牙均为三根三根管的病例,为临床根管治疗及牙拔除术提供借鉴。     

牙列缺损的牙位易感性分析

目的 了解不同牙位发生牙列缺损的情况,分析牙列缺损的牙位易感性.方法 采取分层整群抽样的方法,对唐山市652名40岁以上中老年人进行口腔健康状况检查.分析比较各牙位的牙缺失率.结果 上颌左侧876颗（19.19%）牙齿缺失,右侧955颗（20.92%）牙齿缺失,下颌左侧819颗（17.94%）牙齿缺失,右侧891颗（19.52%）牙齿缺失,同侧不同牙位之间牙缺失率比较差异均有统计学意义（均P＜0.01）,上颌1831颗（20.05%）牙齿缺失,下颌1710颗（1873%）牙齿缺失,上颌顺序为第一磨牙＞第二磨牙＞第二前磨牙＞第一前磨牙＞中切牙＞侧切牙＞尖牙,下颌为第一磨牙＞第二磨牙＞第二前磨牙＞中切牙＞第一前磨牙＞侧切牙＞尖牙.结论 牙列缺损的发生呈明显对称性,不同牙位发生牙列缺损的易感性不同.     

上颌磨牙近中颊根第二根管的定位

目的　通过对 77颗离体牙根管数目的检查 ,对近中颊根第二根管口 (MB2 )与近中颊根管口(MB)腭侧根管口 (P)的相对位置分布的规律进行观察分析 ,为临床治疗提供依据。方法　选择 77颗上颌离体牙 ,其中上颌第一磨牙 35颗 ,上颌第二磨牙 4 2颗 ,截冠后寻找近中颊根及其第二根管 ,并取得上颌恒磨牙根管口间距及根管口连线夹角等数据。结果　上颌第一、二恒磨牙近中颊根存在第二根管的有 36颗 ,占总数的 4 6 .75 % ,其中有1 5颗牙近中颊第二根管钙化不通 ,2 3颗牙近中颊根的第二根管口位于腭侧与近中颊第一根管口连线的近中处 ,近中颊根管口至近中颊第二根管口的距离为 1 .2 8± 0 .35 mm ,腭侧根管口至近中颊根管口的距离为 2 .98± 0 .4 7mm ,近中颊第二根管口至 P- MB线的垂直距离为 0 .6 3± 0 .1 2 mm,P- MB线与 MB- MB2 线的夹角为 2 5 .1 4°± 8.0 3°。结论　在上颌恒磨牙根管治疗时应注意根管系统的变异 ,改进开髓洞形 ,掌握查找近中颊根第二根管方法 ,以免遗漏根管     

塑化根充填联合治疗上颌第一磨牙的疗效观察

上颌第一磨牙是主要的咀嚼牙齿,是临床上常易患牙髓病,根尖周病的牙齿之一,因其解剖结构、尤其是根管结构较为特殊及复杂,为临床上治疗带来了许多不便,我院从１９９７年初至今采取塑化根充联合治疗上颌第一磨牙的牙髓病、根尖周病１８６颗患牙;取得了较为满意的临床效果,现将结果报道如下。１上颌第一磨牙根管解剖特点 上颌第一磨牙通常情况下由三个牙根组成。两根在颠侧,一根在舌侧,舌侧牙根即腭侧牙根最大,远中颊根一般较近中颊根短小。一般为三根三管,也有三根四管等。腭侧根管较直,较粗大,近远中须根管较细小,弯曲,有时…     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.