Healing responses following transverse root fracture: a historical review and case reports showing healing with (a) calcified tissue and (b) dense fibrous connective tissue

Background

The understanding and management of transverse intra‐alveolar root fractures has evolved to its current high level of sophistication and clinical success from foundations laid down by histological studies as early as the mid‐nineteenth century.

Significance

The aim of the review was to highlight those earlier histological reports and studies that have contributed to the current understanding of the biological processes involved in the healing of transverse root fractures. Healing of a transverse root fracture by calcified tissue was demonstrated histologically by Howe in 1926, while Boulger in 1928 showed the two other patterns of root fracture healing, namely the interposition of fibrous connective tissue and the interposition of bone and periodontal ligament around both fractured segments. Other major histological reports around that time came from members of the so‐called ‘The Vienna group of Illinois’, who had a significant influence in the development of oral biology worldwide. Other important reports and an experimental study emanated from Germany and Switzerland in the late 30s and early 40s, followed in the 1950s and early 1960s by histological material principally from Sweden, Denmark, France, the USA and Britain. Jens Andreasen and Erik Hjörting‐Hansen's landmark paper in 1967 included new histological reports and a classification of healing responses following transverse root fractures. The expansion of knowledge related to root fractures since that time has been exponential, with major contributions from Scandinavia and several other countries.

Case reports

Accompanying the historical review are two case reports with histology of root fracture healing by (a) calcified tissue and (b) dense fibrous connective tissue. The role of the pulp and the periodontal ligament in the repair process is described and the clinical significance discussed with particular emphasis to diagnosis and orthodontic management.     

肝上皮样血管内皮瘤1例

上皮样血管内皮瘤(epithelioid hemangioendothelioma,EHE)是一种病因及发病机制不明,累及单个或多个器官的血管源性肿瘤,具有低至中度恶性潜能,呈慢性进行性发展过程.肝脏是EHE受累的常见器官之一.Ishak等[1]在1984年首次报道了肝上皮样血管内皮瘤(hepatic epithelioid hemangioendothelioma,HEHE),此后相关报道逐渐增多.影像学检查是诊断HEHE常用的手段之一,如螺旋X线计算机断层摄影术(CT)、磁共振成像(MRI)、核医学检查等,但存在一定的局限性.我们在此报道1例病史长达17年的HEHE患者的肝脏CT灌注特点及其在HEHE诊断中的价值.     

Hybrid hollow silica particles: synthesis and comparison of properties with pristine particles

In the past decade, interest in hollow silica particles has grown tremendously because of their applications in diverse fields such as thermal insulation, drug delivery, battery cathodes, catalysis, and functional coatings. Herein, we demonstrate a strategy to synthesize hybrid hollow silica particles having shells made of either polymer-silica or carbon–silica. Hybrid shells were characterized using electron microscopy. The effect of hybrid shell type on particle properties such as thermal and moisture absorption was also investigated.

Hybrid hollow silica particles, which show different properties compared to their pristine counterparts, have been synthesized.

In the past decade, hollow particles have attracted a great deal of interest because of their unique properties (e.g., high surface area, low density, and encapsulated cavity) compared with their dense counterparts. Hollow particles of several materials, including polymers, silica, titania, carbon, and zinc oxide have been reported.^1–9 Among these, hollow silica particles have attracted great attention from scientists because of their low material cost; well understood chemistry; and potential applications in widespread areas such as thermal insulation, drug delivery, energy storage, phase change encapsulation, catalysis, and superhydrophobic coatings.^10–18 Hollow silica particles can be synthesized using various approaches, such as by employing polymer micelles, immiscible solvent emulsions, inorganic or polymer (e.g., polystyrene) particles, and bacterial or virus cells as templates; by etching solid silica particles; or by spray pyrolysis.^19–25 Polymer micelles or emulsions provide very small particles, but making larger particles and tuning particle size are challenges in this approach. Similarly, the obtained particles typically fuse with one another, and achieving individually separated particles is a challenging task. Inorganic template etching is a time-consuming process, and in many cases, rudiments of inorganic templates remain in the hollow particle cavity if etching is incomplete. Unconventional techniques such as spray drying are inexpensive, but particle size control is difficult. The use of polystyrene particles as templates is attracting much attention because polystyrene particles can be synthesized at low cost with controlled sizes. Polystyrene particle-based synthesis of hollow silica particles involves three steps: (1) synthesis of polystyrene particles, (2) deposition of silica shells on polystyrene particles, and (3) removal of the polystyrene core by burning or dissolving to obtain hollow silica particles.Synthesis of hollow silica particles having shells made of silica alone (pristine hollow particles) is well reported. Some previous efforts have been made to attach surfactant molecules to the surfaces of mesoporous (not hollow) hollow particles. For example, Zhang et al.²⁶ first made porous silica particles by using cetyltrimethylammonium bromide (CTAB) as the template. In the next step, sodium carbonate-based etching was used to create cavities inside the porous particles, thus leading to porous-hollow silica particles. Then, 3-mercaptopropyl-trimethoxysilane (MPTS) was used to attach thiol-group ending surfactants to the surface. Similarly, Ribeiro et al.²⁷ coated solid silica particles with poly(butyl methacrylate) to make superhydrophobic coatings. Similarly, hollow polymer particles have been reported by depositing a polymer layer around solid silica particles, followed by etching the silica core. The same hollow polymer particles were also converted to hollow carbon particles by pyrolysis of polymer.^28,31 However, in this work, shell is made of a single material – polymer or carbon.^28,31 To the best of our knowledge, no work has reported hollow particles with a hybrid shell – shell made of two layers of different materials (inner layer: silica and outer layer: polymer or carbon). Additionally, no previous report has investigated the effect of such an additional layer on the properties of the hollow silica particles. We envisage that such additional layers can change the properties, such as stability against moisture and thermal conductivity, of pristine hollow silica particles.We report the synthesis of hybrid hollow silica particles, characterize these hybrid particles, and compare their properties with the properties of pristine hollow silica particles. Our investigations reveal that by changing the coating material, several intrinsic properties of hollow silica particles can be modified.Hollow silica particles were synthesized by modifying previously reported strategies based on the use of polystyrene particles (synthesis details in ESI S1^†) as a template.¹ For synthesizing hollow silica particles, in a typical experiment, 0.25 g of polystyrene particles were mixed into 100 mL of ethanol/water (ethanol 80 mL, water 20 mL). A suitable amount of tetraethyl orthosilicate was added to make complete shells around the polystyrene particles. To increase the TEOS hydrolysis, 28–30% of ammonium hydroxide was used as a catalyst. Fig. 1a depicts a schematic of hollow particle formation. Fig. 1b shows an SEM image of the polystyrene particles used as templates, and Fig. 1c shows a transmission electron microscope (TEM) image of polystyrene core-silica shell particles. Fig. 1d shows an SEM and Fig. 1e shows a high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image of hollow silica particles obtained after burning the polystyrene core by keeping the sample at 550 °C for 4 h.Open in a separate windowFig. 1(a) Schematic showing synthesis of hollow silica particles. (b) SEM image of polystyrene particles. (c) TEM image of polystyrene core coated with silica shell (core–shell). (d) SEM and (e) HAADF-STEM image of hollow silica particles.There are several polymers that can be used to form coatings on silica.^28–31 Among these, the use of resorcinol is well studied.^28,31 In a typical experiment, 0.25 g of hollow particles (0.25 g) were mixed in water (100 mL). Ammonium hydroxide (28–30%, 500 μL), resorcinol (0.1 g), and formaldehyde (150 μL) were added to this reaction mixture. The reaction was allowed to proceed overnight (≈16 h) to completion. Expected mechanism for polymer coating formation is explained in ESI S3.^†Fig. 2a shows a schematic of the process used to make a polymer (polyresorcinol) coating on a silica shell. Fig. 2b shows low-magnification (i) and high-magnification (ii) TEM images of polymer-coated hollow silica particles. The polymer coating can be clearly seen (light in contrast) around the silica shell (dense in contrast). Though TEM imaging confirmed the presence of a polymer coating on the surface of the silica, to further confirm the formation of the coating, we applied electron energy loss spectroscopy (EELS). Energy dispersive X-ray (EDX) imaging is easy to use and is a readily available technique for analysing materials; however, EDX has a very low sensitivity to low-atomic-weight elements such as carbon and oxygen. Therefore, it was not a suitable technique for confirming the polymer presence. In contrast, EELS is known for its high sensitivity to low-atomic-weight elements (e.g., carbon and oxygen). Fig. 2c shows scanning HAADF-STEM (i) and EELS (ii) images of the polymer-silica hybrid shell. The coating was quite uniform, with some thicker areas on the free surfaces of particles and some thinner areas at the joints in aggregated particles (ESI S2^†). Therefore, if individual uniform coatings are required, the original hollow particle samples must be properly disaggregated.Open in a separate windowFig. 2(a) Schematic showing the polymer coating process. (b) TEM images of polymer-coated silica particles. (c) HAADF-TEM (i) and EELS S map (ii) showing polymer and silica layers of hybrid shell.Additionally, we demonstrated the formation of hybrid hollow silica particles with outer layers made of carbon and inner layers made of silica. To form a carbon layer on a silica shell, the initial polymer coating was sintered in an inert atmosphere (argon) at 550 °C for 4 h. Fig. 3a shows a schematic of polymer layer conversion to a carbon layer. Under these conditions, polymer converts into carbon instead of being completely oxidized into carbon dioxide and water. After heating under an inert atmosphere, brown polymer-coated particles changed to black carbon-coated particles. Separate carbon (outer) and silica (inner) layers were observed in TEM (Fig. 3b) and EELS images (Fig. 3c).Open in a separate windowFig. 3(a) Schematic showing conversion of polymer coating to carbon coating. (b) TEM images of carbon-coated particles. (c) EELS element map showing the carbon layer on a silica shell.In addition to making hybrid shell hollow particles, we investigated whether the coating affected the properties (e.g., thermal conductivity and moisture absorption) of the pristine hollow silica particles. We measured the thermal conductivity of pristine, polymer-coated, and carbon-coated particles. The results showed that polymer-coated particles had the lowest thermal conductivity and carbon-coated particles had the highest thermal conductivity of the three types. The Fig. 4 plot shows the thermal conductivities of the three types of particles, and respective insets show photos of corresponding particle samples. More details of the measurements are provided in ESI-S3.^† As expected, the polymer silica particles had lower thermal conductivity (0.022 ± 0.002 W m⁻¹ K⁻¹) than pristine hollow particles (0.024 ± 0.002 W m⁻¹ K⁻¹), whereas carbon-coated particles had higher thermal conductivity (0.036 ± 0.004 W m⁻¹ K⁻¹) than both the pristine and the polymer-coated particles. This information provides a new tool to achieve or tune thermal properties of hollow silica particles as desired. For example, for high-thermal-insulation materials, polymer-coated particles are ideal; whereas carbon-coated particles are more suitable where somewhat higher thermal conductivity, but hydrophobicity is required. We were expecting that a carbon coating will increase electrical conductivity of hollow particles, however, we observed that even carbon coated particles had an electrical resistance in the megaOhm range, i.e., behave as electrically insulators (measurement details in ESI S3^†). Although the thermal conductivity of polymer-coated or carbon-coated hollow silica particles can be further modified by modifying the coating thickness, in the present work, we did not investigate the effect of coating thickness on thermal conductivity in detail. We expect the thinner the coating, the lower the thermal conductivity will be. We observed in both the polymer- and carbon-coated particles that the coatings were not uniform. Some particles had thick and others thin coatings, indicating that coating nucleation was not uniform, and the coatings may have begun forming earlier on some particles than on others. We observed that carbon–silica hollow particles are hydrophobic in nature, staying afloat on water for several hours (ESI Fig. S4^†) and mixing in water only after vigorous stirring. It appears that, with stirring, water molecules enter the hollow particle cavities through the pores present in the carbon and silica shells and wet the inner parts of the cavities, thus causing the particles to mix in water.Open in a separate windowFig. 4Effect of different types of coatings on the thermal conductivity of hollow silica particles. Insets show the photos of respective particles.Additionally, we compared the moisture absorption properties of pristine hollow silica particles with those of polymer- and carbon-coated hollow silica particles (Fig. 5). Moisture absorption/desorption experiments were performed using a dual vapor gravimetric sorption analyser. We observed that polymer-coated particles absorbed less humidity compared with pristine particles at the same relative humidity. However, both materials had similar isotherm profiles in which the moisture adsorption capacity increased at relatively higher moisture concentrations. The carbon-coated particles, on the other hand, showed a completely different isotherm behaviour: an immediate increase in adsorption capacity was observed between 30% and 50% relative humidity. A sharp increase in moisture absorption at higher relative humidity (between 30–50%) appears due to the entry of water vapors inside the particles because of porous nature of carbon layer. Similar shape of isotherms for pristine and polymer coated particles indicates that both of these particles had similar surface groups (–OH), but lower absorption in polymer coated particles compared to pristine particles indicates that its surface has a small number of moisture absorbing groups (–OH) compared to pristine particles. The hysteresis between adsorption and desorption isotherms was found to be minimal, indicating that the samples had similar performance for adsorption or desorption process. We expect this information to be helpful for applications such as developing water-stable coatings or insulation materials by using hollow silica particles.Open in a separate windowFig. 5Effect on moisture adsorption and desorption process. Plot showing behaviour of hollow particles under different relative humidity conditions for pristine and coated samples.     

生脉注射液治疗急性心肌梗死后心源性休克的临床研究

目的研究生脉注射液治疗急性心肌梗死后心源性休克的临床疗效。方法选取2015年6月—2016年8月十堰市太和医院治疗的急性心肌梗死后心源性休克患者164例,随机分为对照组和治疗组,每组各82例,对照组给予常规治疗,治疗组在对照组的基础上静脉滴注生脉注射液,60 m L加入5%葡萄糖溶液250~500 m L,1次/d。两组均连续治疗7 d。治疗后,观察两组患者临床疗效,同时比较血清心肌肌钙蛋白I(c Tn I)、钙调蛋白(Ca M)及其基因表达,心功能指标左心室内压最大上升速率(dp/dtmax)、左心室内压最大下降速率(-dp/dtmax)、左室射血分数(LVEF)、舒张末期室间隔厚度(IVST)、左心室收缩末期内径(LVESD)、左心室舒张末期内径(LVEDD)、心脏指数(CI),及肺毛细血管楔压(PCWP)、心率(HR)、收缩压(SBP)、舒张压(DBP)、脉压(PP)和尿量(UV)的变化。结果治疗后,对照组和治疗组总有效率分别为60.97%和74.39%,两组总有效率比较差异有统计学意义(P0.05)。两组c Tn I、Ca M、c Tn I-m RNA和Ca MKII-m RNA均较治疗前显著降低,同组治疗前后差异有统计学意义(P0.05),且治疗组上述指标降低更明显,两组比较差异有统计学意义(P0.05)。两组±dp/dtmax、LVEF和CI均升高、LVEDD增大,IVST和LVESD均缩小(P0.05),且治疗组上述指标改善更明显(P0.05)。两组患者PCWP和HR均降低,SBP和DBP均升高,PP增大,UV增多(P0.05),且治疗组上述指标改善更明显(P0.05)。治疗组并发症中室间隔穿孔、急性肾衰竭和心律失常和死亡率明显低于对照组,两组比较差异具有统计学意义(P0.05)。结论生脉注射液治疗急性心肌梗死后心源性休克疗效显著,纠正急性心肌梗死时心肌"钙超载"现象,明显增强心脏泵血功能,具有一定的临床推广应用价值。     

硫化氢供体型美金刚衍生物的合成及其活性

H₂S具有保护缺血再灌注损伤的神经元、显著降低脑梗死面积的作用,但高浓度H₂S产生神经毒性。N-甲基-D-天冬氨酸(NMDA)受体拮抗剂美金刚可以降低高浓度H₂S引起的神经毒性。将硫化氢缓释供体5-对羟基苯基-1,2-二硫杂环戊烯-3-硫酮(ADT-OH)与美金刚通过烷烃连接臂拼合,设计了9个结构全新的化合物I₁~I₉,以ADT-OH为原料,经过4步反应得到目标化合物,其化学结构经¹H NMR、¹³C NMR和HRMS确证。利用MTT法评价不同浓度目标化合物对谷氨酸损伤的HT-22细胞的影响,结果发现,该类化合物在1 μmol/L时能明显提高受损HT-22细胞的生存率(P<0.01),对于谷氨酸诱导损伤的神经元细胞具有较好的保护作用。     

高效液相色谱法同时测定蒙药阿那日-4散中3种成分的含量

目的：建立蒙药阿那日-4散（石榴、肉桂皮、白豆蔻、荜茇）中有效成分没食子酸、桂皮醛和胡椒碱的含量测定方法。方法：采用反相高效液相色谱法以Promosil C₁₈（4.6 mm×250 nm,5μm）为色谱柱;以乙腈-1%冰乙酸水溶液为流动相,梯度洗脱;流速为1.0 mL·min^-1;柱温为30℃;检测波长为290 nm。结果：没食子酸在0.08~0.4μg·mL^-1（r=0.9998）、桂皮醛在0.56~2.81μg·mL^-1（r=0.9996）、胡椒碱在0.52~2.59μg·mL^-1（r=0.9997）范围内与峰面积呈良好的线性关系;其平均回收率（n=6）分别为99.5%（RSD=2.3%）、99.3%（RSD=2.8%）和98.5%（RSD=2.2%）;6批样品中上述3种成分平均含量范围分别为0.198~0.241,2.44~2.61,1.41~1.54μg·g^-1。结论：所建立方法操作简便、稳定可靠、专属性强、准确度及重复性较好,为蒙药阿那日-4散质量检测提供依据。     

O型臂导航引导下经皮椎体成形术治疗中段胸椎骨质疏松性椎体压缩骨折的精准性及安全性

目的 探讨O型臂导航引导下经皮椎体成形术（percutaneous vertebroplasty,PVP）在治疗中段胸椎骨质疏松性椎体压缩骨折的精准性及安全性。方法 2019年12月—2021年8月复旦大学附属浦东医院骨科收治中段胸椎骨质疏松性椎体压缩骨折（osteoporotic vertebral compression fracture,OVCF）患者15例（15个椎体）,男5例,女10例;年龄70~89岁,平均（76.7±5.8）岁。均采用O型臂导航引导下经单侧穿刺行PVP治疗。主要疗效指标：术中规划路径与实际路径的符合率,微创经皮开路器穿刺成功需要的次数,主要指标用于评价该手术操作的精准性。次要疗效指标包括：记录患者术前、术后2天以及末次随访时视觉模拟（visual analogue scale,VAS）疼痛评分,Oswestry功能障碍指数（Oswestry disability index,ODI）。同时记录患者的手术时间、骨水泥使用量、术中出血量及手术相关并发症发生情况等,测量并记录术前、术后2天及末次随访时伤椎前缘高度,次要指标用于评价该手术方案的临床疗效与安全性。结果 15例患者均顺利完成手术,术中规划路径与实际路径的符合率：优6例,良9例,优良率达100%,所有病例均为1次穿刺成功,无患者出现骨水泥渗漏或严重并发症。平均随访11.7个月。术前、术后2天及末次随访时患者VAS评分分别为7.2±0.7、2.3±0.5和1.9±0.5,患者ODI评分分别为68.1±4.0、23.6±4.3和23.0±4.6,患者伤椎前缘高度分别为（2.4±0.3）cm、（2.7±0.3）cm和（2.6±0.3）cm。术后2天患者VAS评分、ODI评分较术前明显改善（P<0.05）,术后2天及末次随访时患者伤椎前缘高度较术前均增加（P<0.05）。结论 O型臂导航引导下PVP治疗中段胸椎OVCF,可提高手术操作精准度及安全性,在治疗中段胸椎OCVF中可能具有较大的临床应用价值。     

基于指纹图谱及化学模式识别研究盐制对五子衍宗丸化学成分的影响

目的建立不同炮制品组方五子衍宗丸(Wuzi Yanzong Pills,WYP)的HPLC指纹图谱,研究盐制对WYP化学成分的影响。方法采用HPLC法建立不同炮制品组方WYP的指纹图谱,并进行相似度评价,采用方差分析、聚类分析(CA)、主成分分析(PCA)与偏最小二乘法-判别分析(PLS-DA)对结果进行评价。结果 WYP全生品组、药典组、盐制组指纹图谱相似度均大于0.9,标定了18个共有峰,利用对照品指认出绿原酸(5号峰)、鞣花酸(10号峰)、金丝桃苷(11号峰)、异槲皮苷(12号峰)、毛蕊花糖苷(13号峰)、紫云英苷(14号峰)、槲皮素(15号峰)、山柰酚(17号峰)、五味子醇甲(18号峰)9个成分,归属性分析表明峰2来源于枸杞子,峰3、5、7、9、11、12、14、15、17来源于菟丝子,峰6、8、10、16来源于覆盆子,峰13来源于车前子,峰18来源于五味子,峰1是覆盆子和五味子共有成分,峰4是枸杞子和覆盆子共有成分。药物炮制后组方WYP未出现色谱峰的增加,但峰面积发生变化。通过CA将WYP全生品组、药典组、盐制组聚为3类,PCA筛选出4个主成分,PLS-DA标记出峰1、13(毛蕊花糖苷)、10(鞣花酸)、7、4、11(金丝桃苷)、12(异槲皮苷)、3、5(绿原酸)共9个差异性成分;绿原酸、鞣花酸、金丝桃苷、异槲皮苷、山柰酚、五味子醇甲及峰1、3、4、7、8共11个成分可能是不同炮制品组方WYP的差异标志物。结论建立的指纹图谱测定方法稳定、可靠,炮制后组方WYP的化学成分发生变化,结果可为WYP中如何选用药物炮制品提供一定的依据。