The influence of protein solubilisation, conformation and size on the burst release from poly(lactide-co-glycolide) microspheres.

Encapsulation of proteins in poly(lactide-co-glycolide) microspheres via emulsion is known to cause insoluble protein aggregates. Following protein emulsification and encapsulation in PLGA microspheres, we used circular dichroism to show that the recoverable soluble protein fraction also suffers subtle conformational changes. For a panel of proteins selected on the basis of molecular size and structural class, conformational stability measured by chemical denaturation was not indicative of stability during emulsion-encapsulation. Partial loss of structure was observed for alpha-helical proteins released from freeze-dried microspheres in aqueous buffer, with dramatic loss of structure for a beta-sandwich protein. The addition of sucrose (a lyoprotectant) did not prevent the loss of protein conformation upon encapsulation. Therefore, the conformational changes seen for the released soluble protein fraction originates during emulsification rather than microsphere freeze-drying. Analysis of the burst release for all proteins in buffer containing denaturant or surfactant showed that the degree of protein solubilisation was the dominant factor in determining the initial rate and extent of release. Our data for protein release into increasing concentrations of denaturing buffer suggest that the emulsion-denatured protein fraction remains insoluble; this fraction may represent the protein loss encountered upon comparison of protein encapsulated versus protein released.     

Oral mifepristone 600 mg and vaginal gemeprost for mid-trimester induction of abortion: An open multicenter study

This open multicenter study was performed in 20 hospital gynecological units in the UK. The effects of 600 mg oral mifepristone as pretreatment to vaginal prostaglandin induction of second second trimester abortion was studied in 267 women.

The primary efficacy variable was the abortion induction interval, defined as the time taken to expel the fetus from the time of administration of the first prostaglandin pessary. Induction was commenced 36 to 48 hours following mifepristone intake.

The mean abortion induction interval was 7 h. A total of 81.9% of women aborted within 12 h. There was a significant relationship between abortion induction interval and age of gestation, and a significant inverse relationship between abortion induction interval and parity.

Vomiting, pelvic pain, and nausea were the most frequently reported adverse events. Two patients required transfusion and one patient with a uterine scar from a previous cesarean section suffered a ruptured uterus and hysterotomy.     

构建玻片蛋白质芯片的实验研究

目的:探讨玻片蛋白质芯片的构建方法及其中间操作条件的选择与优化。方法:利用生物芯片点样仪将超微量蛋白质点到经特殊处理的玻璃片表面,然后选用不同的化学试剂对玻片背景进行封闭;再用荧光素标记的蛋白质与点样蛋白杂交;最后用生物芯片分析仪扫描成像并进行分析,比较不同条件下芯片的显示效果。结果:蛋白质样品与片基稳定结合,并保持原活性状态;封闭试剂选用酪蛋白或明胶效果较佳;点样探针与其特异蛋白质抗体可稳定结合,结合效果与点样蛋白浓度在一定范围内呈正相关;在1.6 cm×1.6 cm的玻璃片面积上,构建了36×36=1269点的蛋白质芯片。结论:本实验条件下,蛋白质抗原或抗体可以稳定地固定于经过处理的玻璃片表面.制成免疫型蛋白芯片,并可通过随后的抗原抗体反应与荧光素标记的相应抗体或抗原结合,用生物芯片分析仪可对其荧光信号进行检测分析。     

Pharmacokinetics and metabolism of the pharmacologically active 4'-hydroxylated metabolite of propranolol in the dog

The disposition of 4'-hydroxypropranolol (HOP) was determined after iv administration to dogs (2 mg/kg; N = 5) and the pharmacokinetic parameters were calculated from plasma measurements. The clearance of HOP, 66 +/- 6 ml/min/kg (mean +/- SE), was considerably higher than that of propranolol previously determined, suggesting extrahepatic as well as hepatic clearance of HOP. The plasma half-life of HOP, 77 +/- 6 min, was shorter than that of propranolol. Although HOP is considerably less lipophilic than propranolol, its volume of distribution, 6.4 +/- 0.8 liter/kg, surprisingly, was larger. Like propranolol, HOP appeared to be cleared entirely by metabolism. Whereas propranolol is metabolized mainly by oxidation, HOP was metabolized to sulfate (HOPS) and glucuronic acid (HOPG) conjugates. The plasma half-lives of these conjugates were 2 to 3 times longer than for HOP, reflecting a slow, continuous formation from HOP. This was established for HOPS by iv administration of synthetic HOPS. Morover, after HOP administration both formation and renal clearance of HOPS were stereoselective in favor of the R-enantiomer. In summary, the main conclusion of this study is that the large volume of distribution as well as high clearance through sulfation and glucuronidation may explain the low plasma HOP levels observed during propranolol therapy.     

The challenges facing nurse-midwives in working towards Safe Motherhood in Malawi

A midwife is the only health worker most of the women of the childbearing group in Malawi will ever meet in their lifetime. A midwife plays an essential role in the promotion of health and provision of care to these women. It is therefore, very important that midwives be available for the well being of these women. However, mere presence of midwives is not adequate for women''s optimal health.     

Biofilm formation by Candida dubliniensis

Candida dubliniensis is an opportunistic yeast closely related to Candida albicans that has been recently implicated in oropharyngeal candidiasis in human immunodeficiency virus-infected patients. Most manifestations of candidiasis are associated with biofilm formation, with cells in biofilms displaying properties dramatically different from free-living cells grown under normal laboratory conditions. Here, we report on the development of in vitro models of C. dubliniensis biofilms on the surfaces of biomaterials (polystyrene and acrylic) and on the characteristics associated with biofilm formation by this newly described species. Time course analysis using a formazan salt reduction assay to monitor metabolic activities of cells within the biofilm, together with microscopy studies, revealed that biofilm formation by C. dubliniensis occurred after initial focal adherence, followed by growth, proliferation, and maturation over 24 to 48 h. Serum and saliva preconditioning films enhanced the initial attachment of C. dubliniensis and subsequent biofilm formation. Scanning electron microscopy and confocal scanning laser microscopy were used to further characterize C. dubliniensis biofilms. Mature C. dubliniensis biofilms consisted of a dense network of yeasts cells and hyphal elements embedded within exopolymeric material. C. dubliniensis biofilms displayed spatial heterogeneity and an architecture showing microcolonies with ramifying water channels. Antifungal susceptibility testing demonstrated the increased resistance of sessile C. dubliniensis cells, including the type strain and eight different clinical isolates, against fluconazole and amphotericin B compared to their planktonic counterparts. C. dubliniensis biofilm formation may allow this species to maintain its ecological niche as a commensal and during infection with important clinical repercussions.     

Congenital clubfoot in Europe: A population‐based study

We aimed to assess prevalence, birth outcome, associated anomalies and prenatal diagnosis of congenital clubfoot in Europe using data from the EUROCAT network, and to validate the recording of congenital clubfoot as a major congenital anomaly by EUROCAT registries. Cases of congenital clubfoot were included from 18 EUROCAT registries covering more than 4.8 million births in 1995–2011. Cases without chromosomal anomalies born during 2005–2009, were randomly selected for validation using a questionnaire on diagnostic details and treatment. There was 5,458 congenital clubfoot cases of which 5,056 (93%) were liveborn infants. Total prevalence of congenital clubfoot was 1.13 per 1,000 births (95% CI 1.10–1.16). Prevalence of congenital clubfoot without chromosomal anomaly was 1.08 per 1,000 births (95% CI 1.05–1.11) and prevalence of isolated congenital clubfoot was 0.92 per 1,000 births (95% CI 0.90–0.95), both with decreasing trends over time and large variations in prevalence by registry. The majority of cases were isolated congenital clubfoot (82%) and 11% had associated major congenital anomalies. Prenatal detection rate of isolated congenital clubfoot was 22% and increased over time. Among 301 validated congenital clubfoot cases, diagnosis was confirmed for 286 (95%). In conclusion, this large population‐based study found a decreasing trend of congenital clubfoot in Europe after 1999–2002, an increasing prenatal detection rate, and a high standard of coding of congenital clubfoot in EUROCAT.