Selective coating of cylindrical matrices with a central hole. I. An interpretation of the swelling process

Cylindrical matrices were prepared by compression either of polyvinyl alcohol 100000 or mixtures of the excipient and a drug (sodium salicylate or theophylline). To modify the cylindrical shape, a hole was bored in the centre of the flat surface through both sides of the matrices. Different swellable systems were obtained applying an impermeable coating to one, two or three surfaces of the perforated matrices. The swelling of the perforated matrices was modified according to the number and the position of the coated surfaces (selective coating) and the loaded drug. Pseudo-zero order kinetics were obtained when the interior hole was the only uncoated surface.     

三氯乙烯诱发SD大鼠产生免疫反应的模型研究

目的研究SD大鼠对三氯乙烯(trichloroethylene,TCE)免疫刺激的反应,拟建立大鼠对TCE免疫反应的模型.方法背部皮内注射体积分数为15%的TCE免疫SD大鼠,1周1次,免疫5次后于大鼠左后足跖膜下注射TCE攻击,6h称左右后足重量计算肿胀度.取TCE免疫大鼠心脏血,分离并培养单个核细胞.将培养的细胞与系列浓度的TCE共同培养2d后,检测细胞酸性磷酸酶的活性,据此判断细胞的活化增殖程度.结果 TCE免疫大鼠攻击足肿胀度与空白对照组大鼠的相比差异显著(P＜0.005).体积分数为3%的TCE可使培养的大鼠血单个核细胞的增殖达到峰值.结论重复皮内注射TCE可使SD大鼠产生某种免疫反应.SD大鼠的单个核细胞可被TCE刺激活化.     

自制可调式冰袋对髋膝关节置换术后患者疼痛及引流量的影响

目的 探究髋膝关节置换术后患者应用自制可调式冰袋对其疼痛及引流量的影响.方法 选取海安市中医院2018年4月至2020年4月收治的髋膝关节置换术患者126例为研究对象,按随机数字表法分为对照组和观察组各63例.对照组采用常规冰袋冰敷,观察组采用自制可调式冰袋冰敷.对比两组患者手术后关节引流量、肿胀度及疼痛情况.结果 观...     

不同软组织肿胀情况下两种方法治疗GartlandⅢ型儿童肱骨髁上骨折的效果比较

目的 比较不同软组织肿胀情况下闭合复位内固定与切开复位内固定方式治疗GartlandⅢ型儿童肱骨髁上骨折的效果,探讨软组织情况对于治疗方式选择及预后的影响.方法 回顾分析2008年1月～2013年12月于宁波市第六医院采用闭合复位内固定或切开复位内固定方式治疗,年龄在7～11岁并得到随访6～24个月(平均11个月)的GartlandⅢ型肱骨髁上骨折患儿155例,按治疗时软组织肿胀情况分为轻度肿胀组和中、重度肿胀组,参照Flynn肱骨髁上骨折疗效评定标准,比较不同软组织条件下两种治疗方式对骨折预后的影响.结果 155例根据骨折软组织肿胀情况分组:轻度肿胀组41例,采用闭合复位内固定39例,其中优35例,良4例,优良率为100％;切开复位2例,优1例,良1例,优良率100％.中、重度肿胀组114例,采用闭合复位内固定28例,其中优7例,良16例,可4例,差1例,优良率为82.1％;切开复位86例,优50例,良27例,可8例,差1例,优良率为89.5％.在中、重度肿胀组,两种治疗方式间疗效差异有统计学意义(x2=-9.549,P=0.023).结论 对于Gartland Ⅲ型肱骨髁上骨折,软组织肿胀程度直接影响预后,在明显肿胀发生前采用闭合复位的方式可以得到较好的疗效,对于软组织已经明显肿胀的病例切开复位的方式效果会更好,而不是等待骨形态重塑或截骨矫形治疗.     

Randomized clinical study comparing Piezoelectric Surgery with conventional rotatory osteotomy in mandibular third molars surgeries

PurposeThe aim of this study was to evaluate the performance and to assess the postoperative sequel and quality of life after removal of impacted mandibular third molars using piezoelectric surgery compared with conventional rotatory osteotomy.Patients and methodsA single blinded, randomized, control clinical study was performed. Sixty-three patients (44 males, 19 females) who presented with bilaterally asymptomatic impacted mandibular third molars were included in this analysis. Each patient was treated, at two separate sessions approximately 4 weeks apart, with a conventional rotatory hand piece on one side of the mandible and a piezoelectric device on the contralateral side. Patients were followed up on postoperative days 1, 3, 5, 7, and 15 to rate the pain, swelling and trismus. Inferior alveolar nerve paresthesia was evaluated up to 12 months postoperatively.ResultsThe severity of the pain, trismus and swelling using the piezosurgery were significantly different from the rotary group. In both groups, pain was most intense and peaked during the first post-operative day, while swelling and trismus reached peak levels on the third postoperative day. The piezoelectric procedure resulted in a significantly longer procedural duration compared to the rotatory surgery (P < 0.001).ConclusionPiezoelectric surgery is considered a viable alternative technique compared to the conventional rotary systems and can improve a patient’s quality of life. Thus, piezoelectric surgery might be a preferred modality for patients undergoing complicated surgical extraction of impacted lower third molars.     

Exposure of natural rubber to personal lubricants – swelling and stress relaxation as potential indicators of reduced seal integrity of non-lubricated male condoms

Background

Male condoms act as mechanical barriers to prevent passage of body fluids. For effective use of condoms the mechanical seal is also expected to remain intact under reasonable use conditions, including with personal lubricants. Absorption of low molecular weight lubricant components into the material of male condoms may initiate material changes leading to swelling and stress relaxation of the polymer network chains that could affect performance of the sealing function of the device. Swelling indicates both a rubber-solvent interaction and stress relaxation, the latter of which may indicate and/or result in a reduced seal pressure in the current context.

Methods

Swelling and stress relaxation of natural rubber latex condoms were assessed in a laboratory model in the presence of silicone-, glycol-, and water-based lubricants.

Results

Within 15 minutes, significant swelling (≥ 6 %) and stress reduction (≥ 12 %) of condoms were observed with 2 out of 4 silicone-based lubricants tested, but neither was observed with glycol- or water-based lubricants tested. Under a given strain, reduction in stress was prominent during the swelling processes, but not after the process was complete.

Conclusions

Lubricant induced swelling and stress relaxation may loosen the circumferential stress responsible for the mechanical seal. Swelling and stress relaxation behavior of latex condoms in the presence of personal lubricants may be useful tests to identify lubricant-rooted changes in condom-materials.

Implication

For non-lubricated latex condoms, material characteristics – which are relevant to failure – may change in the presence of a few silicone-based personal lubricants. These changes may in turn induce a loss of condom seal during use, specifically at low strain conditions.     

肿胀麻醉微创治疗青春期男性乳腺增生症

目的探讨应用肿胀麻醉乳晕切口微创治疗青春期男性乳腺增生症的临床经验。方法采取肿胀麻醉乳晕切口微创治疗39例青春期男性乳腺增生症患者。结果39例患者均手术顺利，术后无一例出现血肿、感染、乳头乳晕坏死，胸部平整对称。随访28例，时间为6～12个月，术区瘢痕不明显，胸部平坦，无复发。结论肿胀麻醉乳晕切口微创治疗青春期男性乳腺增生症是一种操作简单、安全性高、彻底的治疗方法。     

An in vitro investigation for vaginal bioadhesive formulations: bioadhesive properties and swelling states of polymer mixtures

Bioadhesive tablet formulations have been developed for mucosal application. Sixteen different bioadhesive tablet formulations were prepared and evaluated. Their bioadhesion to vaginal mucosa were studied by tensile testing method. The swelling behaviour of the tablets in three different solutions was also investigated. In addition, the effect of the formulations on pH of the medium was followed. The most favorable formulation resulted a mixture of Carbopol 934 and Pectin (2:1). The highest bioadhesive strength, the highest swelling volume and the lowest pH reduction were obtained with this formulation.     

Probing the dynamics of matrix hydration in the presence of electrolytes

The aim of our work was to probe the mechanisms associated with induced matrix stiffening via textural analysis as a consequence of in situ electrolyte interactions within hydroxypropylmethylcellulose (HPMC) and polyethylene oxide (PEO) matrices in relation to their role in controlling the release of highly soluble drugs such as diltiazem hydrochloride (>50% water soluble at 25°C). The dynamics of HPMC and PEO matrix swelling during hydration in the presence of appropriate electrolytes intended to induce constant drug release rates from simple monolithic systems are influenced by continuously shifting peripheral matrix stiffening toward the matrix core in a manner dependent on electrolyte content and hydration time. Matrix erosion for HPMC and PEO controls (i.e., without electrolyte) follow linear dissolution kinetics (r² > 0.97), while formulations with electrolyte characteristically undergo a square root of time decline in weight. The swelling potential of the electrolyte-containing matrices, influenced by the boundary infiltration process, reflected considerable suppression during the first 2 hr of exposure to medium, while subsequent events differed in both polymers. In view of these differences, simultaneous measurements in textural transitions and electrolyte conductivity showed that PEO has a higher affinity for water molecules than does HPMC.     

The influence of substitution type on the performance of methylcellulose and hydroxypropylmethycellulose in gels and matrices

The characteristics of matrices containing hydroxypropylmethylcellulose (HPMC) grades E4M, F4M or K4M, or methylcellulose A4M have been compared using thermomechanical analysis, differential scanning calorimetry (DSC), laser analysis, cloud points and via the dissolution of a model drug, propranolol hydrochloride, from matrices containing the cellulose ethers and prepared by direct compression. Dissolution rates of propranolol varied according to the drug/cellulose ether ratio within the matrix. Propranolol release from methylcellulose matrices was least affected by this ratio but the performance differences of the three grades of HPMC could not be distinguished. In the absence of drug, matrices containing methylcellulose disintegrated at 37 and 44°C. Water uptakes, as measured by DSC and gel layer thicknesses, were similar for each grade of cellulose ether. Matrices containing HPMC K4M tended to swell to the greatest extent. For all grades, swelling was greater in the axial rather than radial direction. Cloud points provided the best prediction of matrix performance.