Disruption of the Candida albicans CYB5 gene results in increased azole sensitivity

Sterol synthesis in fungi is an aerobic process requiring molecular oxygen and, for several cytochrome-mediated reactions, aerobically synthesized heme. Cytochrome b(5) is required for sterol C5-6 desaturation and the encoding gene, CYB5, is nonessential in Saccharomyces cerevisiae. Cyb5p and Ncp1p (cytochrome P-450 reductase) appear to have overlapping functions in this organism, with disruptions of each alone being viable. The cytochrome P-450 reductase phenotype has also been shown to demonstrate increased sensitivity to azole antifungals. Based on this phenotype, the CYB5 gene in the human pathogen Candida albicans was investigated to determine whether the cyb5 genotype was viable and would also demonstrate azole sensitivity. Sequential disruption of the CYB5 alleles by direct transformation resulted in viability, presumably conferred by the presence of a third copy of the CYB5 gene. Subsequent disruption procedures with a pMAL2-CYB5 rescue cassette and a CYB5-URA3 blaster cassette resulted in viable cyb5 strains with no third copy. The C. albicans CYB5 gene is concluded to be nonessential. Thus, the essentiality of this gene and whether we observed two or three alleles was dependent upon the gene disruption protocol. The C. albicans cyb5 strains produced a sterol profile containing low ergosterol levels and sterol intermediates similar to that reported for the S. cerevisiae cyb5. The C. albicans cyb5 shows increased sensitivity to azoles and terbinafine, an inhibitor of squalene epoxidase, and, unexpectedly, increased resistance to morpholines, which inhibit the ERG2 and ERG24 gene products. These results indicate that an inhibitor of Cyb5p would not be lethal but would make the cell significantly more sensitive to azole treatment.     

What is the role of plain radiography in patients with foreign bodies in the gastrointestinal tract?

Foreign bodies (FBs) in the gastrointestinal (GI) tract can show a wide range of clinical manifestations ranging from spontaneous evacuation to severe complication. Plain radiography is a straightforward and important initial imaging modality in cases of FB ingestion or insertion and is also helpful for follow-up purposes. Careful evaluations of the plain radiographs can determine the presence and nature of FBs, and help predict their precise locations and facilitate risk assessment. In this review, a wide variety of FBs in the GI tract are illustrated, and the role of plain radiography in patient management is discussed.     

A New MRI Grading System for Cervical Foraminal Stenosis Based on Axial T2-Weighted Images

ObjectiveThe purpose of this study was to evaluate the reliability of a new magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (NFS).ResultsFor the distinction among the three individual grades at all six neural foramina, the ICC ranged from 0.68 to 0.73, indicating fair to good reproducibility. The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement. The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.ConclusionThe new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.     

神经外科常见引流管相关并发症的分析及护理对策

目的 分析神经外科常见引流管相关并发症,总结护理经验.方法 选择我院近两年神经外科住院病人术后留置引流管的患者作为研究对象,加强护理前的为对照组,共153例,加强护理后的为研究组,共135例,分析术后引流管相关并发症的发生率及原因,得出安全、有效、可行的护理措施.结果 对照组有20例发生引流管相关并发症,发生率为13.1％;研究组发生4例并发症,发生率为3.0％,两组比较差异有统计学意义(P＜ 0.05).正确、细心、及时的术后引流护理是降低术后并发症的关键和保证.结论 加强神经外科术后常见引流管的护理管理,细致认真的临床观察,维持有效的引流,严格控制引流量,结合引流情况及时调节引流管位置,对预防并发症,提高治愈率至关重要.