Biomedical microelectromechanical systems (BioMEMS): Revolution in drug delivery and analytical techniques

Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.     

高渗盐水和甘露醇在动脉瘤性蛛网膜下腔出血患者降低颅内压中的应用

目的比较3%高渗盐水和20%甘露醇治疗重症动脉瘤性蛛网膜下腔出血所致颅内压增高的疗效.方法25例动脉瘤性蛛网膜下腔出血患者出现颅内压增高事件时, 随机交替接受等渗透剂量的160 mL 3%高渗盐水与150 mL 20%甘露醇进行降低颅内压治疗, 连续监测患者颅内压、平均动脉压、脑灌注压及中心静脉压.记录有效降低颅内压持续时间、颅内压最大降幅及其时间, 用药前及用药后1 h、3 h血钠水平及血浆渗透压.结果3%高渗盐水和20%甘露醇均可降低颅内压(均 P < 0.01), 两者的降低颅内压作用持续时间及颅内压降幅差异均无统计学意义(均 P >0.05).患者脑灌注压较用药前均上升(均 P < 0.01), 平均动脉压先上升后下降, 但差异无统计学意义( P >0.05).患者中心静脉压稍有波动, 但差异均无统计学意义(均 P >0.05).20%甘露醇治疗后患者血钠下降, 3%高渗盐水治疗后患者血钠值上升, 变化均有统计学意义(均 P < 0.05).20%甘露醇及3%高渗盐水治疗后患者血浆渗透压均先上升后下降, 变化均有统计学意义(均 P < 0.01). 结论3%高渗盐水可作为治疗动脉瘤性蛛网膜下腔出血所致颅内压增高患者的一线治疗药物.     

《艾滋病诊疗指南第三版(2015版)》更新解读

2015年中华医学会感染病学分会艾滋病学组发布了第三版《艾滋病诊疗指南》。新版指南强调抗病毒治疗时点前移:一旦成人确诊感染人类免疫缺陷病毒(HIV), 若无禁忌宜尽早启动抗HIV治疗。对于合并机会性感染的HIV感染者, 在感染控制、病情稳定后也应及早开始抗病毒治疗。尤其强调HIV合并结核患者在CD4阳性淋巴细胞数少于200/μL的情况下, 建议抗结核两周内即开始抗病毒治疗。在抗HIV治疗用药中, 淘汰了一些毒副作用大、依从性较差的药物, 如司他夫定、去羟肌苷、茚地那韦等, 优选抗病毒效力强、服药方便的组合, 如拉米夫定、替诺福韦、依非韦伦组合。对于HIV感染的婴幼儿, 亦主张及早抗HIV治疗。对于五岁以内的幼儿, 主张确诊后即启动抗病毒治疗。对于HIV感染的孕产妇, 建议尽快予以全程、联合抗HIV治疗, 寓防于治。     

Outbreak of Burkholderia cepacia complex bacteremia in a chemotherapy day care unit due to intrinsic contamination of an antiemetic drug

Background: In the end of 2009, a large number of patients with cancer undergoing chemotherapy at the day care unit of a private hospital in Mumbai, India developed Burkholderia cepacia complex (BCC) blood stream infection (BSI). Objective: The objectives were to identify the source of the outbreak and terminate the outbreak as rapidly as possible. Materials and Methods: All infection control protocols and processes were reviewed. Intensive training was started for all nursing staff involved in patient care. Cultures were sent from the environment (surfaces, water, air), intravenous fluids, disinfectants and antiseptics and opened/unopened medication. Results: A total of 13 patients with cancer with tunneled catheters were affected with BCC BSI. The isolates were of similar antimicrobial sensitivity. No significant breach of infection control protocols could be identified. Cultures from the prepared intravenous medication bags grew BCC. Subsequently, culture from unused vials of the antiemetic granisetron grew BCC, whereas those from the unopened IV fluid bag and chemotherapy medication were negative. On review, it was discovered that the outbreak started when a new brand of granisetron was introduced. The result was communicated to the manufacturer and the brand was withdrawn. There were no further cases. Conclusions: This outbreak was thus linked to intrinsic contamination of medication vials. We acknowledge a delay in identifying the source as we were concentrating more on human errors in medication preparation and less on intrinsic contamination. We recommend that in an event of an outbreak, unopened vials be cultured at the outset.     

A highly tumor-targeted nanoparticle of podophyllotoxin penetrated tumor core and regressed multidrug resistant tumors

Podophyllotoxin (PPT) exhibited significant activity against P-glycoprotein mediated multidrug resistant (MDR) tumor cell lines; however, due to its poor solubility and high toxicity, PPT cannot be dosed systemically, preventing its clinical use for MDR cancer. We developed a nanoparticle dosage form of PPT by covalently conjugating PPT and polyethylene glycol (PEG) with acetylated carboxymethyl cellulose (CMC-Ac) using one-pot esterification chemistry. The polymer conjugates self-assembled into nanoparticles (NPs) of variable sizes (20–120 nm) depending on the PPT-to-PEG molar ratio (2–20). The conjugate with a low PPT/PEG molar ratio of 2 yielded NPs with a mean diameter of 20 nm and released PPT at ∼5%/day in serum, while conjugates with increased PPT/PEG ratios (5 and 20) produced bigger particles (30 nm and 120 nm respectively) that displayed slower drug release (∼2.5%/day and ∼1%/day respectively). The 20 nm particles exhibited 2- to 5-fold enhanced cell killing potency and 5- to 20-fold increased tumor delivery compared to the larger NPs. The biodistribution of the 20 nm PPT-NPs was highly selective to the tumor with 8-fold higher accumulation than all other examined tissues, while the larger PPT-NPs (30 and 120 nm) exhibited increased liver uptake. Within the tumor, >90% of the 20 nm PPT-NPs penetrated to the hypovascular core, while the larger particles were largely restricted in the hypervascular periphery. The 20 nm PPT-NPs displayed significantly improved efficacy against MDR tumors in mice compared to the larger PPT-NPs, native PPT and the standard taxane chemotherapies, with minimal toxicity.     

HIV Protease: Historical Perspective and Current Research

The retroviral protease of human immunodeficiency virus (HIV) is an excellent target for antiviral inhibitors for treating HIV/AIDS. Despite the efficacy of therapy, current efforts to control the disease are undermined by the growing threat posed by drug resistance. This review covers the historical background of studies on the structure and function of HIV protease, the subsequent development of antiviral inhibitors, and recent studies on drug-resistant protease variants. We highlight the important contributions of Dr. Stephen Oroszlan to fundamental knowledge about the function of the HIV protease and other retroviral proteases. These studies, along with those of his colleagues, laid the foundations for the design of clinical inhibitors of HIV protease. The drug-resistant protease variants also provide an excellent model for investigating the molecular mechanisms and evolution of resistance.     

Measuring the appropriateness of carbamazepine and valproic acid prescribing and utilization using a newly implemented online system in the Tabuk Region of Saudi Arabia

Epilepsy is a common neurologic disorder, which is efficiently treated with carbamazepine and valproic acid. Moreover, Saudi Ministry of Health implemented a new E-system for Poison Control Centers called Awtar to enhance technology utilization in ensuring patients’ satisfaction and to improve treatment outcomes. Therefore, we conducted this study to assess appropriateness of indication of requests and therapeutic levels of carbamazepine and valproic acid in Tabuk area, North West Saudi Arabia. This is a retrospective observational study conducted in Poison Control & Forensic Chemistry Center, Tabuk, Saudi Arabia. Patients’ data were obtained for years 2018 and 2019. The blood levels of carbamazepine and valproic acid were measured by Therapeutic Drug Monitoring (TDM) Unit. We selected patients treated with either valproic acid or carbamazepine alone without any history of drug allergy. Data of 264 patients were extracted from Awtar E-system. Serum carbamazepine levels were within therapeutic range in 114 patients (75.50%), above-therapeutic range in 13 patients (8.61%) and sub-therapeutic levels in 24 patients (15.89%). Regarding serum valproic acid, it is within therapeutic range in 62 patients (54.87%), above-therapeutic range in 11 patients (9.73%) and sub-therapeutic levels in 40 patients (35.40%). In conclusion, this study gives information about partial appropriateness of usage of carbamazepine and low level of appropriateness of valproic acid. However, more efforts are needed to improve results of appropriateness of indication of antiepileptic drugs.