国家级首批线上一流课程免疫学基础与病原生物学的建设与推广

线上一流课程作为一种新型的教学课堂模式,其建设与推广不仅使教师的教和学生的学呈现多元化,而且也使教师的教学和研究水平、学生的学习兴趣和能力得到了有效提升。本团队建设与推广的国家级首批线上一流课程免疫学基础与病原生物学已经完成6个学期的运行,累计学习人数40 395人,累计选课学校84所。本文从建设背景与建设目标、整体框架与建设资源、实施过程与推广应用、教学运行与互动、教学考核与评价、思考和展望等6个方面总结该课程的建设与推广情况。     

Effects of high doses of glucocorticoids on free amino acids,ribosomes and protein turnover in human muscle

BACKGROUND: Treatment with glucocorticosteroids causes a negative nitrogen balance, but the kinetic mechanisms responsible for this catabolic effect are controversial. We investigated the effects of 60 mg day(-1) prednisolone on protein synthesis and degradation in human skeletal muscle. MATERIALS AND METHODS: Healthy adults (n = 9) were studied in the postabsorptive state, before and after 3 days of prednisolone treatment. The L-[ring 2,6(-3)H(5)]-phenylalanine tracer technique, concentration and size distribution of the ribosomes, mRNA content of the ubiquitin-proteasome pathway components in muscle, phenylalanine flux across the leg, and the free amino acid concentrations in skeletal muscle were used to study muscle protein metabolism. RESULTS: The concentrations of most amino acids in arterial blood increased after prednisolone. There were also increased effluxes of phenylalanine, asparagine, arginine, alanine, methionine and isoleucine from the leg. The rate of protein degradation, as measured by the appearance rate (Ra) of phenylalanine, increased by 67% (P = 0.023) which, together with a doubling of the net release of phenylalanine from the leg (P = 0.007), indicated accelerated protein degradation. The pathway was not identified but there was no significant increase in mRNAs' encoding components of the ubiquitin-proteasome pathway. There was a 6% reduction in polyribosomes (P = 0.007), suggesting a decrease in the capacity for protein synthesis, although there was no measured decrease in the rate of protein synthesis. CONCLUSIONS: These findings indicate that high doses of prednisolone lead to a sharp increase in net protein catabolism, which depends more on enhanced protein breakdown, and an uncertain effect on protein synthesis. The mechanisms stimulating proteolysis and the pathway stimulated to increase muscle protein degradation should be explored.     

Involvement of endocytic organelles in the subcellular trafficking and localization of riboflavin

Previous studies by our laboratory have suggested the potential role of receptor-mediated endocytosis components in the cellular translocation of riboflavin (vitamin B2). To delineate the intracellular compartments and events involved in the internalization of riboflavin, we synthesized a rhodamine-labeled riboflavin conjugate to monitor its movement via fluorescent microscopy. Cellular uptake studies in BeWo cells show that rhodamine-riboflavin conjugate exhibits similar ligand affinity toward the putative riboflavin transport system as [3H]riboflavin, whereas rhodamine does not significantly interfere with its internalization mechanism. Microscope analysis reveals rapid internalization of the rhodamine-riboflavin conjugate via a riboflavin-specific process into acidic vesicular compartments throughout the cells. The intracellular punctate distribution is comparable with that of fluorescein isothiocyanate (FITC)-transferrin, a well characterized receptor-mediated endocytosis substrate. Double-labeling fluorescence microscopy studies further confirm that with 10 min of internalization, rhodamine-riboflavin conjugate substantially concentrates within vesicular structures associated with clathrin, rab5, FITC-transferrin, and the acidotropic marker LysoTracker Blue. In summary, our studies provide, for the first time, direct morphological evidence of the involvement of endocytosis machinery in the intracellular trafficking of riboflavin. The subcellular localization of rhodamine-riboflavin conjugate suggests that, under the experimental conditions in this study, the internalization of riboflavin follows a classical receptor-mediated endocytosis pathway.     

Direct identification of Yersinia enterocolitica in blood by polymerase chain reaction amplification

Primers based on the nucleotide sequence of the virF gene in the pYV plasmid and the chromosomal ail gene were used in polymerase chain reaction (PCR) amplifications to directly identify Yersinia enterocolitica in blood. Approximately 500 bacteria seeded into 100 microL of blood can be extracted and amplified by PCR to yield positive results. PCR analyses of seven Y. enterocolitica isolates previously implicated in blood contaminations showed that only one isolate harbored the plasmid-borne virF gene; however, all seven isolates were identified effectively by the PCR product amplified from the chromosomal gene. The PCR assay has the potential for use in the identification of Y. enterocolitica contamination in stored units of blood or in the rapid diagnosis of transfusion-related bacteremia caused by Y.     

Criteria for choosing clinically effective glaucoma treatment: A discussion panel consensus

Abstract

Background:

In the clinical management of patients at risk for or diagnosed with primary open-angle glaucoma (POAG), the aim of medical treatment is to reduce intraocular pressure (IOP) and then maintain it over time at a level that preserves both the structure and function of the optic nerve.

Objective:

The objective of this report was to establish a consensus on the criteria that should be used to determine the characteristics of IOP-lowering medication.

Methods:

Discussion was held among a panel of 12 physicians considered to be experts in glaucoma to develop a consensus on the criteria used by them to determine the characteristics of the IOP-lowering medication chosen for initial monotherapy and adjunctive treatment of ocular hypertension (OHT) or POAG. Consensus development combined available evidence and the impressions of these physicians regarding the clinical effectiveness of IOP-lowering medication for OHT and POAG. Once the panel identified the criteria, the order of priority and the relative importance of these criteria were then established in the setting of 3 risk categories (low, medium, and high) for a patient to experience significant visual disability from glaucoma over their expected life span.

Results:

The panel identified 5 criteria to determine the characteristics of IOP-lowering medication for OHT and POAG: IOP-lowering effect, systemic adverse events (AEs), ocular tolerability, compliance/administration, and cost of treatment. IOP-lowering effect was consistently ranked as the highest priority and cost as the lowest. The priority of compliance/administration did not vary by clinical situation. Systemic AEs and ocular tolerability were ranked as higher priorities in initial monotherapy than in adjunctive treatment and ranked lower as the risk for visual disability increased. The priority given to the criteria used to determine clinical effectiveness varied both with the risk for functional vision loss from glaucoma and whether initial monotherapy or adjunctive treatment was being considered.

Conclusion:

Glaucoma treatment should be assessed with regard to the need not only to lower IOP but also to minimize systemic and ocular AEs, promote patient compliance, and minimize cost. The order of priority and relative importance given to these treatment criteria will vary as part of individualizing patient care.Key Words: consensus, criteria, intraocular pressure, glaucoma     

Pharmacokinetics and Tissue Disposition of Lenalidomide in Mice

Lenalidomide is a synthetic derivative of thalidomide exhibiting multiple immunomodulatory activities beneficial in the treatment of several hematological malignancies. Murine pharmacokinetic characterization necessary for translational and further preclinical investigations has not been published. Studies herein define mouse plasma pharmacokinetics and tissue distribution after intravenous (IV) bolus administration and bioavailability after oral and intraperitoneal delivery. Range finding studies used lenalidomide concentrations up to 15 mg/kg IV, 22.5 mg/kg intraperitoneal injections (IP), and 45 mg/kg oral gavage (PO). Pharmacokinetic studies evaluated doses of 0.5, 1.5, 5, and 10 mg/kg IV and 0.5 and 10 mg/kg doses for IP and oral routes. Liquid chromatography–tandem mass spectrometry was used to quantify lenalidomide in plasma, brain, lung, liver, heart, kidney, spleen, and muscle. Pharmacokinetic parameters were estimated using noncompartmental and compartmental methods. Doses of 15 mg/kg IV, 22.5 mg/kg IP, and 45 mg/kg PO lenalidomide caused no observable toxicity up to 24 h postdose. We observed dose-dependent kinetics over the evaluated dosing range. Administration of 0.5 and 10 mg/kg resulted in systemic bioavailability ranges of 90–105% and 60–75% via IP and oral routes, respectively. Lenalidomide was detectable in the brain only after IV dosing of 5 and 10 mg/kg. Dose-dependent distribution was also observed in some tissues. High oral bioavailability of lenalidomide in mice is consistent with oral bioavailability in humans. Atypical lenalidomide tissue distribution was observed in spleen and brain. The observed dose-dependent pharmacokinetics should be taken into consideration in translational and preclinical mouse studies.     

Antibiotic prophylaxis for total joint replacement surgery: results of a survey of Canadian orthopedic surgeons

Background

The role of perioperative antibiotic prophylaxis in total joint replacement (TJR) surgery is well established. Whereas guidelines have been published in some countries, in Canada controversy persists concerning the best clinical practice for perioperative antibiotic prophylaxis in TJR.

Methods

We conducted a survey of 590 practising orthopedic surgeons performing TJR in Canada to assess current antibiotic prophylaxis practice. The survey included questions pertaining to antibiotic prophylaxis indications, antibiotic choice, dosing, route and timing of administration in the primary and revision arthroplasty setting, as well as postoperative wound drainage evaluation and management.

Results

The response rate after 2 mail-outs was 410 of 590 (69.5%). Current antibiotic prophylaxis regimens varied widely among surgeons, underscoring the controversy that exists regarding what constitutes best clinical practice.

Conclusion

Opinions regarding use of perioperative antibiotic prophylaxis in TJR vary widely among orthopedic surgeons in Canada, illustrating the controversy as to what constitutes best clinical practice. This survey also points to a lack of consensus about the current management of postoperative wound drainage.     

How parents choose to use CAM: a systematic review of theoretical models

Background  

Complementary and Alternative Medicine (CAM) is widely used throughout the UK and the Western world. CAM is commonly used for children and the decision-making process to use CAM is affected by numerous factors. Most research on CAM use lacks a theoretical framework and is largely based on bivariate statistics. The aim of this review was to identify a conceptual model which could be used to explain the decision-making process in parental choice of CAM.