纤维桩修复根管治疗牙体缺损疗效观察

目的：探讨纤维桩利用其独特的物理化学性质,保存修复残根残冠的临床应用。例如在桩核冠中的应用效果如何,及利用纤维桩修复牙体缺损恢复牙体形态的成效。方法：112例患者的168颗患牙经完善根管治疗且牙周组织健康、牙根有足够长度的牙体缺损患牙。其中穿髓型楔状缺损的牙齿缺损10颗,邻面缺损7颗,因特殊原因不做冠7颗,残根残冠修复形成桩核冠144颗。结果：经过2年的临床观察,168颗牙齿中161颗完好,7例失败,其中1例舌侧充填体折断松动,2例牙体组织折断,充填体和纤维桩完好,3例牙颈部折断,1例纤维状脱落,牙根完好。成功率为95.8%。其中桩核冠修复成功率为97.1%,牙体修复成功率为88.8%。结论：纤维桩通过树脂黏接剂与根管牙本质形成较高的黏接强度,使牙根与修复体之间连接成为一个坚固的整体,从而延长修复体和牙体组织的使用寿命,使修复后的患牙可以承载各种口腔功能性应力。     

Species comparison of vitamin K1 2,3-epoxide reductase activity in vitro: kinetics and warfarin inhibition

A comparative study of vitamin K(1) 2,3-epoxide reductase (VKOR) activity in vitro was conducted across species. The apparent kinetic constants K(m app), V(max), and Cl(int app) were determined in bovine, canine, equine, human, murine, ovine, porcine, and rat hepatic microsomes. In addition to these enzyme kinetic constants, the IC(50) of warfarin for VKOR was determined in human, murine, porcine, and rat hepatic microsomes. Interspecies differences were observed when comparing the K(m app) (range, 2.41-6.46 microM), V(max) (range, 19.5-85.7 nmol/mg/min), and Cl(int app) (range, 8.2-18.4 ml/mg/min) values. Comparison of the IC(50) values of warfarin, across the four species tested, revealed a significant species difference between murine microsomes (0.17 microM) and rat microsomes (0.07 microM). Overall, this study indicates that there are interspecies differences regarding the in vitro reduction of vitamin K(1) 2,3-epoxide by the warfarin-sensitive enzyme vitamin K(1) 2,3-epoxide reductase. Significant differences between the IC(50) values of murine and rat microsomes suggest differences in the susceptibility of these species to warfarin.     

Feline polymorphonuclear leukocytes respond chemotactically to leukotriene B4 and activated serum but not to F-Met-Leu-Phe

The chemotactic response of feline polymorphonuclear leukocytes (PMNs) to three types of chemoattractants was studied. Feline PMNs responded to leukotriene B4 as well as to agarose-activated autologous and homologous serum. However, no response was obtained to N-formylmethionylleucylphenylalanine (FMLP), and four similar peptides that activate the FMLP receptor (N-formylnorleucylleucylphenylalanine, N-formylmethionylphenylalanine, methionylleucylphenylalanine, and pepstatin). Thus, feline PMNs are similar to equine, porcine, bovine and canine PMNs which also do not respond chemotactically to these peptides.     

Detection of the administration of human erythropoietin (HuEPO) to canines

Recombinant human erythropoietin (rHuEPO) doping is prohibited in animal (canine and equine) sport. The effectiveness of a range of immunoassay screening methods for the detection of rHuEPO in canine urine was evaluated. The excretion profiles following rHuEPO administration to dogs were investigated. The presence of rHuEPO in postadministration samples was confirmed using the World Anti-Doping Agency (WADA)-approved isoelectric focusing immunoblotting confirmatory technique. Following the administration study, a screening program involving approximately 6000 greyhound sport (mostly racing) samples was undertaken for rHuEPO. This resulted in the detection of the first rHuEPO positives in the world of canine or equine sport. In an additional case, endogenous HuEPO was detected in a sample submitted as greyhound urine. It was determined that this arose from the submission to control stewards, as greyhound urine, of a substance that was, in fact, human urine. This was a particularly welcome development as definitive confirmatory evidence of such sample switching can be difficult to obtain in the case of greyhounds.     

Bone regeneration by synthetic octacalcium phosphate and its role in biological mineralization

Octacalcium phosphate (Ca8H2(PO4)6 * 5H2O; OCP) has been advocated to be a precursor of biological apatite crystals in bone and tooth. Recent studies, using physical techniques, showed that OCP is present as a transient phase during biological apatite formation in human dentin, porcine enamel and murine bone. However, there is still a controversy regarding the chemical nature of the first mineral formed in the biominerals. A number of studies have demonstrated that synthetic OCP shows bone regenerative and biodegradable characteristics, rather than other calcium phosphate bone substitute materials, such as hydroxyapatite (Ca10(PO4)6(OH)2; HA) ceramic. It seems likely that synthetic OCP may be an alternative to autogenous bone graft. It is known that OCP contains alternative layers of water molecules and an apatite structure, and that the transition of OCP to HA is likely to be spontaneous and irreversible. The conversion process induces modification of local environment adjacent to OCP surface, including the changes in adsorption of serum proteins and concentration of calcium and inorganic phosphate ions. This article reviews the possible application to bone regeneration by synthetic OCP and the mechanism to enhance bone regeneration in relation to biological mineralization in bone and tooth.     

In vitro assessment of the mucoadhesion of cholestyramine to porcine and human gastric mucosa.

Previous in vivo studies have suggested that the extended gastric residence and uniform intragastric distribution of cholestyramine may be due to mucoadherent properties. This series of in vitro investigations explored the possibility of the anion exchange resin exhibiting bioadhesive behaviour, and investigated the characteristics, such as particle size and surface charge, that may affect it. Tensile strength measurements were carried out to determine the mucoadhesion of cholestyramine and other test materials (resin particulates, polymers and hydrogels) with varying adhesive properties, to isolated porcine and human gastric mucosa. Optimal instrumental parameters for the system were determined initially and used; all procedures were carried out at room temperature (22 degrees C). The particle size of cholestyramine did not affect mucoadhesion to either porcine or human gastric mucosa (P=0.673, porcine; P=0.969, human), whilst anionic exchangers were found to provide better mucoadhesion than cationic exchangers (P=0.0002, porcine; P=0.0009, human). In some instances, it was found that the detachment forces recorded were lower with human gastric mucosa than with porcine gastric mucosa, although this was not consistently statistically significant. A rank order of mucoadhesion was constructed from a comparison of cholestyramine with eight other test materials. Cholestyramine produced the second highest degree of mucoadhesion, with Carbopol producing the greatest adhesion. Dextran and polyethylene glycol did not display good mucoadhesion under these conditions. From the findings presented here, we have found that cholestyramine demonstrates good mucoadhesion to both porcine and human gastric mucosa when compared to other known bioadhesives. It is suggested that particle size does not contribute to this mucoadherent behaviour but the surface charge of the resin has a significant part to play.     

Immuno-affinity purification of specific antibodies against human gastrin releasing peptide (h-GRP) by the h-GRP(1–8)-linked poly dimethylacrylamide resin

A new method for immuno-affinity purification of specific antibodies against human gastrin releasing peptide(h-GRP) was developed. The antiserum GP(No. 6201) elicited by h-GRP-BSA conjugate was hetereogeneous and reacted not only with h-GRP and its fragments but also partially with other structurally related peptides, such as other GRPs (porcine, canine, and chicken), bombesin, and neuromedin-C. To obtain specific antibodies against human GRP, antiserum GP was purified by column chromatography on the amino-terminal octapeptide h-GRP(1–8)-linked polydirnethylacrylamide resin. The antibody thus obtained was highly specific to amino-terminal sequence of h-GRP and hardly reacted with other GRPs (porcine, canine and chicken), bombesin, and even carboxy-terminal h-GRP fragments in ELISA.     

马和犬流感病毒的流行病学、致病性及传播研究进展

甲型流感病毒（influenza A virus，IAV）主要感染人和动物，禽类和猪是导致IAV基因多样性的主要宿主，而马和犬携带的IAV类型较少，并且几乎不传染人。据报道，马流感病毒（equine influenza virus，EIV）可以跨越从马到犬的宿主物种障碍，在犬群中引起流感暴发。虽然至今尚无人感染EIV和犬流感病毒（canine influenza virus，CIV）的报道，但是随着IAV的不断进化，人类与马和犬的密切接触将会给人类造成潜在公共卫生威胁。此文就EIV和 CIV的流行病学、致病性和传播进行综述，为马和犬流感疫苗研究提供流行病学信息。     

Ammonia toxicity for mammalian and avian lymphocytes from blood

The effect of addition of ammonia to cultures of avian, bovine, cavian, equine, human, leporinae, murine, ovine and porcine blood lymphocytes was studied. The concentrations of ammonia in the lymphocyte cultures represented normal (0.01-0.5 mg/dl), subtoxic (0.5-1 mg/dl), and toxic (1-10 mg/dl) concentrations of ammonia in blood. Viability of the lymphocytes and their mitogenic reactivity were measured. In general, 1.0 and 10 mg/dl of ammonia (toxic concentrations) affected viability and mitogenic responsiveness of all lymphocytes from tested species. The lower concentrations of ammonia affected only avian, bovine and equine lymphocytes.     

Facilitating in vitro tape stripping: application of infrared densitometry for quantification of porcine stratum corneum proteins

Infrared (IR) densitometry is a highly practical method recently proposed for protein analysis during in vivo tape stripping. However, this method has not yet been validated for the quantification of porcine stratum corneum (SC) proteins. Therefore, the aim of this study was to establish calibration curves for the analysis of adhesive tapes removed from porcine ear skin. To this end, the protein absorption (as determined via IR densitometry) was correlated with the protein content determined with the Micro BCA? protein assay after extraction of the tapes. The obtained linear regressions confirm that IR densitometry is suitable for the quantification of not only human, but also porcine, SC proteins. The pattern of protein removal observed with porcine skin differs from that of human skin due to more pronounced corneocyte clustering and deep 'canyons', which necessitates specific evaluation of porcine skin samples and a working protocol that takes this into account. The presented data will facilitate future analysis of porcine SC proteins during in vitro tape stripping.     

PTD4-apoptin protein and dacarbazine show a synergistic antitumor effect on B16-F1 melanoma in vitro and in vivo

PTD4-apoptin protein enters cells and harbors tumor-selective cell death activity. Dacarbazine is the mainstay of treatment for malignant melanoma. In this study, we investigated the cytotoxic effect of PTD4-apoptin protein and/or dacarbazine in mouse B16-F1 and human A875 and SK-MEL-5 melanoma cells in vitro and by means of a mouse B16-F1 melanoma model in vivo. PTD4-apoptin protein inhibits the growth of B16-F1, A875 and SK-MEL-5 melanoma cells in a dose-dependent manner, but not in normal human cell lines WI-38 and L-02. PTD4-apoptin combined with dacarbazine revealed a synergistic cytotoxic effect (coefficient of drug interaction < 1) in all three different tumor cell lines. In vivo, PTD4-apoptin protein and dacarbazine alone effectively inhibited the growth of B16-F1 melanoma in C57BL/6 mice. Strikingly, combined PTD4-apoptin/dacarbazine treatment significantly increased the antitumor effect in comparison to the single treatments. As important, a combined PTD4-apoptin/dacarbazine treatment with a 50% reduction of dacarbazine revealed similar antitumor activities, without detectable hematologic side effects. A combined PTD4-apoptin/dacarbazine treatment represents a promising novel efficient and safe anticancer strategy.     

Species and vascular bed responses of veins and arteries to endothelial-derived relaxing factor in dog and pig

The vascular endothelium is a source of a mediator of vascular smooth muscle (VSM) relaxation known as endothelial-derived relaxing factor (EDRF). Endothelial-dependent relaxation is dependent on the type of vessel under study (artery vs. vein) and on the vascular site from which the blood of vessels are derived. EDRF is released by bradykinin, adenosine, and adenosine triphosphate, substance P, serotonin, arachidonic acid, thrombin, and other relaxant substances. EDRF appears to be a labile substance with a six-second half-life that contains a labile ketone or carbonyl moiety in its active site. EDRF appears to be selectively inhibited by ouabain, pyruvate, and metabolic inhibitors and inactivated by potassium and sodium borohydride. EDRF appears to act by stimulating an increase in cyclic GMP in the smooth muscle cells of porcine tissues and possibly by other mechanisms in canine tissues. Canine veins possess receptors for porcine aortic EDRF but may not make EDRF itself or may have a different endothelial-derived substance than canine arteries. Little is known concerning the factors that release or affect the action of EDRF, its mechanism of action or its chemical composition, especially in the pulmonary vasculature. The differences between release of EDRF from artery and vein and the responses to, and composition of, EDRF in vein and artery remain an area for further research.     

两种黏结系统对牙颈部非龋性硬化牙本质边缘微渗漏的实验研究

目的评价两种牙本质黏结系统对牙颈部非龋性硬化牙本质的边缘封闭效果。方法选取具有典型牙颈部非龋性硬化牙本质的离体牙50颗,随机分为两组,分别应用3M Adper Prompt自酸蚀黏结剂和3M Single Bond 2全酸蚀黏结剂进行窝洞处理,然后用3MZ350纳米树脂充填。经温度循环后,1%亚甲兰溶液染色48h,人工唾液中浸泡24h,然后沿充填体的颊舌向剖开,25倍根管显微镜下观察修复体边缘染料渗漏情况。结果两组样本均有不同程度的染料渗入。所有标本在龈壁处的微渗漏均大于牙合壁处,差异有统计学意义(P<0.05)。无论在龈壁处还是牙合壁处,3M Adper Prompt自酸蚀黏结剂封闭效果均优于3MAdper Single Bond2全酸蚀黏结剂,差异有统计学意义(P<0.05)。结论自酸蚀黏结系统对牙颈部非龋性硬化牙本质的边缘封闭效果优于全酸蚀黏结系统。     

Replacing PAPS: In vitro phase II sulfation of steroids with the liver S9 fraction employing ATP and sodium sulfate

In vitro technologies provide the capacity to study drug metabolism where in vivo studies are precluded due to ethical or financial constraints. The metabolites generated by in vitro studies can assist anti‐doping laboratories to develop protocols for the detection of novel substances that would otherwise evade routine screening efforts. In addition, professional bodies such as the Association of Official Racing Chemists (AORC) currently permit the use of in‐vitro‐derived reference materials for confirmation purposes providing additional impetus for the development of cost effective in vitro metabolism platforms. In this work, alternative conditions for in vitro phase II sulfation using human, equine or canine liver S9 fraction were developed, with adenosine triphosphate (ATP) and sodium sulfate in place of the expensive and unstable co‐factor 3′‐phosphoadenosine‐5′‐phosphosulfate (PAPS), and employed for the generation of six representative steroidal sulfates. Using these conditions, the equine in vitro phase II metabolism of the synthetic or so‐called designer steroid furazadrol ([1′,2′]isoxazolo[4′,5′:2,3]‐5α‐androstan‐17β‐ol) was investigated, with ATP and Na₂SO₄ providing comparable metabolism to reactions using PAPS. The major in vitro metabolites of furazadrol matched those observed in a previously reported equine in vivo study. Finally, the equine in vitro phase II metabolism of the synthetic steroid superdrol (methasterone, 17β‐hydroxy‐2α,17α‐dimethyl‐5α‐androstan‐3‐one) was performed as a prediction of the in vivo metabolic profile.     

根管内不同预处理对玻璃纤维桩粘接强度的影响

目的 比较3种根管内预处理方式对玻璃纤维桩粘接强度的影响。 方法 选用40颗离体无龋单根管前牙,经常规根管治疗和桩道预备后根据不同根管内预处理方式随机分为4组:I组:2%洗必泰溶液组(n=10);Ⅱ组:2.5%次氯酸钠组(n=10);Ⅲ组:35%磷酸凝胶组(n=10);Ⅳ组:生理盐水组(对照组)(n=10),采用自酸蚀双固化树脂水门汀粘接纤维桩后进行薄片推出实验,记录推出时的最大力值,扫描电镜观察根管内壁及粘接界面的微观形态,体视显微镜观察粘接界面的断裂方式。结果 I组粘接强度与对照组比较差异无统计学意义(P >0.05),Ⅱ组粘接强度值小于对照组,差异有统计学意义(P <0.05),但Ⅲ组粘接强度值明显大于对照组,且差异有统计学意义(P <0.05),断裂方式以根管牙本质与粘接材料之间的破坏为主要破坏方式,纤维桩粘接后界面观察:35%磷酸凝胶可见树脂突形成,较为致密,2%洗必泰所形成的树脂突较短,形态规则,2.5% NaClO未见明显树脂突形成。结论 采用自酸蚀系统粘接纤维桩前使用2.5%的NaClO溶液预处理可降低纤维桩粘接强度,35%磷酸凝胶可显著提高纤维桩粘接强度,而2%洗必泰溶液预处理对粘接强度无明显影响。利用35%磷酸凝胶处理可形成良好的树脂突,有利于构成立体网状结构,提高纤维桩的粘接强度。     

DNaseⅠ与Nd：YAP激光联合应用对根管内粪肠球菌生物膜清除作用的影响

目的 研究脱氧核糖核酸酶Ⅰ（DNaseⅠ）与Nd：YAP激光联合应用对根管内粪肠球菌（E.f）生物膜的清除效果。方法 建立牙本质片表面E.f感染模型,应用扫描电子显微镜（SEM）观察感染模型建立情况。将25个培养48 h的E.f生物膜样本采用随机数字表法分为5组,每组5个。A组：0.5%NaOCl;B组：0.5%NaOCl+Nd：YAP激光;C组：DNaseⅠ+0.5%NaOCl;D组：DNaseⅠ+0.5%NaOCl+Nd：YAP激光;E组：生理盐水。激光共聚焦显微镜（CLSM）观察牙本质表面E.f黏附情况,并计数绿色荧光量即为活细菌量。结果 SEM观察可见牙本质表面牙本质小管口开放,E.f黏附聚集在牙本质表面,并见到牙本质小管深层内细菌黏附。CLSM观察可见A、B、C组CLSM图像中绿色荧光的活细菌散在分布于牙本质表面,D组可见较少量的绿色荧光,E组绿色荧光的活细菌覆盖全部样本表面。D组中菌量明显小于A组和E组,C组菌量明显小于E组（P<0.01）。结论 相比于单独使用0.5% NaOCl,DNaseⅠ联合Nd：YAP激光与0.5%NaOCl冲洗能更有效地处理E.f生物膜。     

不同类型粘接剂对牙本质粘接强度及耐久性影响的比较研究

目的:比较不同类型粘接剂对牙本质粘接强度及耐久性的影响,从而为临床上选择粘接剂提供参考。方法:选取2019年1月至2020年6月在暨南大学附属深圳市宝安区妇幼保健院口腔科就诊患者50例,其中男25例、女25例,年龄（42.21±8.27）岁。患者因治疗需要拔除50颗完整无龋人离体第三磨牙,采用随机数字表法将其分A、B、...     

In vivo metabolism of the designer anabolic steroid hemapolin in the thoroughbred horse

Hemapolin (2α,3α‐epithio‐17α‐methyl‐5α‐androstan‐17β‐ol) is a designer steroid that is an ingredient in several “dietary” and “nutritional” supplements available online. As an unusual chemical modification to the steroid A‐ring could allow this compound to pass through antidoping screens undetected, the metabolism of hemapolin was investigated by an in vivo equine drug administration study coupled with GC‐MS analysis. Following administration of synthetically prepared hemapolin to a thoroughbred horse, madol (17α‐methyl‐5α‐androst‐2‐en‐17β‐ol), reduced and dihydroxylated madol (17α‐methyl‐5α‐androstane‐2β,3α,17β‐triol), and the isomeric enone metabolites 17β‐hydroxy‐17α‐methyl‐5α‐androst‐3‐en‐2‐one and 17β‐hydroxy‐17α‐methyl‐5α‐androst‐2‐en‐4‐one, were detected and confirmed in equine urine extracts by comparison with a library of synthetically derived reference materials. A number of additional madol derivatives derived from hydroxylation, dihydroxylation, and trihydroxylation were also detected but not fully identified by this approach. A yeast cell‐based androgen receptor bioassay of available reference materials showed that hemapolin and many of the metabolites identified by this study were potent activators of the equine androgen receptor. This study reveals the metabolites resulting from the equine administration of the androgen hemapolin that can be incorporated into routine GC‐MS antidoping screening and confirmation protocols to detect the illicit use of this agent in equine sports.     

牙齿隐裂与折裂的本征因素初步分析

目的研究隐裂牙与折裂牙的微观结构特点与发病的内在联系,为隐裂牙预防和临床诊疗提供参考依据。方法以折裂拔除的成人磨牙作为研究对象,利用X射线衍射、扫描电子显微镜和红外反射光谱仪方法,对牙釉质和牙本质的微观结构和形貌分别进行观察和比较分析。结果牙本质与牙釉质的化学成分和晶体结构是一致的,主要组成为羟基磷灰石。但牙本质羟基磷灰石结晶颗粒取向分布比较均匀,且尺寸较小,约为几纳米,而牙釉质羟基磷灰石结晶颗粒高度择优取向,颗粒呈线状,线长度达近百纳米。牙齿裂纹可以出现在牙釉质,也可以出现在牙本质。牙本质中有较高的水含量。结论牙齿隐裂可以出现在牙齿表面,也可以出现在牙齿内部。牙齿隐裂和折裂的直接原因是作用在牙齿上的力,但冷热食物的剧烈刺激,也可以导致牙釉质或牙本质首先出现裂纹。而由牙本质出现的牙齿隐裂,比较难以发现和开展早期治疗,需要特别注意。