Dissolution of USP prednisone calibrator tablets: effects of stirring conditions and particle size distribution

We investigate the effect of stirring conditions on the dissolution of United States Pharmacopoeial Convention (USP) prednisone calibrator tablets. The experiments are performed in an automated USP-II dissolution test apparatus. For this study we use a special paddle-propeller, which can be changed from an ordinary paddle to either a pulling or pushing propeller by changing the angle of the paddle blades. According to the dissolution curves obtained we find that the fastest dissolution, and hence best stirring at a certain stirring frequency, is obtained when the blades of the paddle-propeller is about +30°. This setting corresponds to a pushing, downward flow in the centre of the vessel. We show that the shape of the dissolution curves is similar to that expected from a mix of two different fractions of particles, provided that the stirring is sufficiently intense: one fraction, approximately 60 wt.%, with small particles, and one fraction with large particles. The weight of a large particle is about 100–250 times that of a small. We derive a mathematical expression, based on the cube root law, for the dissolution curves. The expression is fitted to the experimental dissolution curves to investigate the variation of key parameters with stirring and temperature.     

Changes in tear protein pattern after photorefractive keratectomy

PURPOSE: Changes in tear protein composition of patients who underwent photorefractive keratectomy (PRK) were analyzed. METHODS: Tear samples were obtained from 23 eyes of 23 patients immediately before PRK and on the fourth postoperative day with glass capillaries. Tear proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Digital image analysis and evaluation of the densitometric data of the electrophoretic separations were done with BioDoc-Analyze. RESULTS: Analysis of discriminance found a significant difference in the protein patterns (p < 0.001). This type of analysis of the electrophoretic densitographs uses all peak information simultaneously. A significant decrease (p < 0.005) in three of the main protein peaks--lactoferrin, immunoglobulin A heavy chain, and lysozyme--was also found after PRK. CONCLUSIONS: Excimer laser ablation of the cornea has an acute effect on lacrimal gland protein secretion. Changes in tear composition may lead to feelings of dryness and to a decrease in tear film stability postoperatively.     

Induction of apoptosis and chemosensitization of mesothelioma cells by Bcl-2 and Bcl-xL antisense treatment

Our study was designed to investigate the role of the anti-apoptotic proteins Bcl-2 and Bcl-xL in the chemoresistance of cells derived from malignant pleural mesothelioma. First, we determined the basal expression levels of Bcl-2 and Bcl-xL in mesothelioma cells and examined the effect of their downregulation by antisense oligonucleotides. Bcl-xL mRNA and protein could be readily detected in mesothelioma cell lines, whereas only low levels of Bcl-2 mRNA and protein were found. Preferential downregulation of either Bcl-xL alone or of Bcl-xL and Bcl-2 simultaneously was achieved by treatment with antisense oligonucleotides 4259 and 4625, respectively, whereas the expression of other apoptosis-relevant genes remained unaffected. Treatment with oligonucleotides 4259 or 4625 lowered the apoptosis threshold in ZL34 mesothelioma cells, as indicated by an increase in cell death accompanied by increased caspase-3-like activity, a decrease of the mitochondrial transmembrane potential and the cleavage of procaspase-7 and ICAD. In addition to the direct induction of apoptosis, antisense treatment sensitized ZL34 cells to the cytostatic effect of cisplatin and gemcitabine, with the combination of 4625 and cisplatin being the most effective. Our results demonstrate that Bcl-2 and Bcl-xL antisense treatment facilitates apoptosis in mesothelioma cells and suggest the use of Bcl-2/Bcl-xL bispecific antisense treatment in combination with cisplatin or gemcitabine for therapy of malignant pleural mesothelioma.     

Glioma after cerebral hydatid disease

Background

The authors present the case of a 31-year-old man with a malignant glioma. He had been treated for cerebral hydatid as a child, and 22 years later he developed a glioma at the site of his previous disease.

Discussion

Could chronic inflammatory change following intracranial hydatid disease have induced neoplastic transformation of glial cells?

     

加强研究能力 促进卫生发展

卫生研究是促进卫生发展的重要动力和战略性措施,研究能力的强弱决定了卫生研究水平的高低,而且影响着卫生事业的发展。在进一步加强卫生研究能力的工作中,要注重加强“硬科学”与“软科学”的有机结合,既要培养二者结合的复合型人才,又要建设二者结合的复合型队伍,更要创造二者结合的研究氛围。只有这样才能在快速变化的环境中发现新问题,解决新问题,控制疾病对人类健康的威胁。使卫生决策更加科学化,卫生资源的利用更加合理化,从而推动卫生事业的发展和人类健康水平的提高。     

Dietary prevention of allergic diseases in infants and small children.

Because of scientific fraud four trials have been excluded from the original Cochrane meta-analysis on formulas containing hydrolyzed protein for prevention of allergy and food intolerance in infants. Unlike the conclusions of the revised Cochrane review the export group set up by the Section on Paediatrics, European Academy of Allergology and Clinical Immunology (SP-EAACI) do not find that the exclusion of the four trials demands a change of the previous recommendations regarding primary dietary prevention of allergic diseases. Ideally, recommendations on primary dietary prevention should be based only on the results of randomized and quasi-randomized trials (selection criteria in the Cochrane review). However, regarding breastfeeding randomization is unethical, Therefore, in the development of recommendations on dietary primary prevention, high-quality systematic reviews of high-quality cohort studies should be included in the evidence base. The study type combined with assessment of the methodological quality determines the level of evidence. In view of some methodological concerns in the Cochrane meta-analysis, particularly regarding definitions and diagnostic criteria for outcome measures and inclusion of non peer-reviewed studies/reports, a revision of the Cochrane analysis may seem warranted. Based on analysis of published peer-reviewed observational and interventional studies the results still indicate that breastfeeding is highly recommended for all infants irrespective of atopic heredity. A dietary regimen is effective in the prevention of allergic diseases in high-risk infants, particularly in early infancy regarding food allergy and eczema. The most effective dietary regimen is exclusively breastfeeding for at least 4-6 months or, in absence of breast milk, formulas with documented reduced allergenicity for at least the first 4 months, combined with avoidance of solid food and cow's milk for the first 4 months.     

重视对正常血压高值人群的随访和治疗

流行病学研究显示血压从115／75mmHg起，心血管疾病（CVD）危险性随血压升高而增加；55岁时血压正常者未来发生高血压的危险为90％；为此JNC7提出了高血压前期的诊断，即120～139mmHg和／或80～89mmHg，建议改善生活方式以预防高血压的发生，并建议针对强适应证（心衰、心梗后、冠心病高危因素、糖尿病、慢性肾病以及预防中风复发）者选择药物降压治疗。我国流行病学研究也显示出同样的结果，中国高血压防治指南定义120～139／80～89mmHg为正常血压高值，并建议降低高血压发病率和CVD病死率应从正常血压高值人群中预防，近期开展的对正常血压高值是否应当降压治疗的讨论中，多数倾向于对正常血压高值人群应给予适当的治疗，包括非药物和药物治疗。     

B超检测脾体积对门脉高压症的临床价值

目的 研究脾形态学变化对肝硬变门脉高压症的临床价值。方法 采用多体位B超扫查检测脾体积、门脉系统血管内径,结合食道静脉曲张程度和术中自由门静脉压力,研究脾体积与它们之间的相互关系。结果 脾肿大反映着门脉压力变化,与门脉各分支循环之间存有代偿关系。结论 B超检测脾体积能及时帮助诊断门脉高压症,脾大小本身还具有监测反映门脉系统高动力循环状态和指导治疗的作用。