Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

26例胰岛细胞肿瘤的临床诊治

目的：探讨功能性与无功能性胰岛细胞肿瘤术前定位方法、术中决策及预后。方法：对1989-2000年12年间收治的26例胰岛细胞肿瘤进行回顾性分析。结果：全组26例，功能组20例，无功能者6例；男性9例（34.6%），女性17例（65.4%），年龄范围：15-72岁；术前23例明确诊断，3例为术后病理诊断证实。功能组B超定位准确率55.0%，CT44.5%，MRI60.0%，血管造影（DSA）71.0%；无功能组B超定位准确率100%，CT100%,MRI66.7%。结论：胰岛细胞肿瘤定位：无功能组较功能组诊断阳性率高，肿瘤体积大，经各种检查仍不能定位时，可根据临床表现实行开腹探查；首选胰岛细胞瘤摘除术，必要时可行胰十二指肠切除或胰体尾切除；对无法彻底切除的恶性胰岛细胞肿瘤，应尽量切除原发和转移病灶。无功能组较功能组治愈率低，生存期较短，预后较差。     

The regulatory protein NIT4 that mediates nitrate induction inNeurospora crassa contains a complex tripartite activation domain with a novel leucine-rich,acidic motif

Expression ofnit-3 andnit-6, the structural genes which encode nitrate reductase and nitrite reductase inNeurospora crassa, requires the global-acting NIT2 and the pathway specific NIT4 regulatory proteins. NIT4, which consists of 1090 amino-acid residues, possesses a Cys₆/Zn₂ zinc cluster DNA-binding-domain. NIT4 was dissected to localize transactivation domains by fusion of various segments of NIT4 to the DNA-binding domain of GAL4 for in vivo analysis in yeast. Three separate activation subdomains, and one negative-acting region, which function in yeast were located in the carboxyl-terminal region of NIT4. The C-terminal tail of 28 amino-acid residues was identified as a minimal activation domain and consists of a novel leucine-rich, acidic region. Most deletions which removed even small segments of the NIT4 protein were found to lead to the loss of NIT4 function in vivo inN. crassa, implying that the central region of the protein which lies between the DNA-binding and activation domains is essential for function. The yeast two-hybrid system was employed to identify regions of NIT4 responsible for dimer formation. A short isoleucine-rich segment downstream from the zinc cluster, predicted to form a coiled coil, allowed dimerization in vivo; this same isoleucine-rich region also showed dimerization in vitro when examined via chemical cross linking. The enzyme nitrate reductase has been postulated to exert autogenous regulation by directly interacting with the NIT4 protein. This possible nitrate reductase-NIT4 interaction was investigated with the yeast two-hybrid system and by direct in vitro binding assays; both assays failed to identify such a protein-protein interaction.     

尿LEU、NIT、HBP及BACT计数检测诊断尿路感染的临床分析

目的 分析尿白细胞酯酶(LEU)、亚硝酸盐(NIT)、肝素结合蛋白(HBP)及细菌(BACT)计数检测诊断尿路感染的临床价值。方法 选择2019年6月—2020年6月期间本院收治的疑似尿路感染患者168例,所有入选者均检测LEU、NIT、HBP、BACT四项指标。以尿培养为金标准,对比LEU、NIT、HBP、BACT四项指标单独及联合诊断价值。结果 168例疑似患者经尿培养发现59例为尿路感染,占35.12%,其中以革兰阴性杆菌最为常见;各指标联合诊断的阳性检出率均高于各项指标单独检测,差异有统计学意义(P<0.05);绘制ROC曲线结果显示,血清LEU、NIT、HBP、BACT及联合诊断用于诊断尿路感染的曲线下面积分别为:0.679、0.711、0.861、0.728、0.974,各指标联合检测诊断性能最高。结论 尿路感染诊断检测LEU、NIT、HBP、BACT方便快捷,能够及时为临床诊断提供参考,各指标单独检测虽有一定价值,但联合检测诊断价值更高。     

Amino-acid substitutions in the zinc finger of NIT2, the nitrogen regulatory protein of Neurospora crassa,alter promoter element recognition

NIT2, the major nitrogen regulatory protein of Neurospora crassa mediates nitrogen catabolite derepression of the structural genes which specify enzymes of nitrogen catabolism. The promoter of the structural gene for L-amino acid oxidase, a nitrogen-regulated enzyme, was found to contain two NIT2 binding sites, each with two copies of a GATA core consensus sequence. Site-directed mutagenesis was employed to create amino-acid substitutions within the single zinc-finger region of NIT2, which serves as the DNA-binding domain. The affect of those mutations upon NIT2 function in vivo in the activation of three separate structural genes was examined by transformation assays and relevant enzyme activities, and DNA-binding activity in vitro was determined by gel band mobility-shift assays. It was shown that specific amino-acid residues within the zinc-finger loop region of NIT2 are important for DNA-binding activity, whereas other residues influence the specificity of DNA binding. Mutant NIT2 proteins were obtained which retain DNA-binding activity and alter the specificity of DNA recognition, thus allowing a distinction between related DNA elements.     

Percentage of filled canal area in mandibular molars after conventional root-canal instrumentation and after a noninstrumentation technique (NIT)

AIM: To compare the percentage of filled canal area in mandibular molar roots after using conventional root-canal hand instrumentation or after a noninstrumentation technique (NIT). METHODOLOGY: Forty mandibular molars were used shortly after extraction. The root canals of 20 molars in the manual group were conventionally prepared using hand instruments and then filled with warm vertical compaction of gutta-percha. The 20 teeth in the second group were cleaned and obturated by NIT. In each case, the entire molar, including the crown and the roots, was embedded in an acrylic resin cylinder before NIT. Horizontal sections were cut at 2, 4, 6 and 8 mm from the apex. Images of the sections were taken using a microscope at x40 magnification and a digital camera; the images were scanned as Tagged Image File Format (TIFF) images into a PC. The cross-sectional area of the canal with the filling materials was measured using an image analysis programme. The percentage of filled area was calculated. The difference in the percentage of filled canal area between the two groups was analysed using a Student's t-test. RESULTS: At all levels, 93-100% of the canal area was filled in both groups. No significant difference was found between the manual technique and the NIT technique at any level (P>0.05). CONCLUSIONS: Within the limitations of this study, following the cleaning and filling of root canals using NIT, the percentage of filled root canal was similar to that using warm vertical compaction of gutta-percha after conventional root-canal instrumentation.     

A two-year dietary carcinogenicity study of cyadox in Sprague-Dawley rats

To investigate the potential carcinogenicity of cyadox, an antimicrobial agent, four groups of Sprague-Dawley rats (50 rats/sex/group) were fed diets containing cyadox (0, 200, 600 or 2000 mg/kg) for up to two years. There were significant decreases in body weight, feed intake and feed efficiency in both genders during most of the period in the 2000 mg/kg group. Significant decreases in serum ALT were observed in the 2000 mg/kg group at weeks 52, 78 and 104. For the control, 200, 600, and 2000 mg/kg groups, the tumor incidence in females was 33.3%, 37.2%, 40.0% and 19.0%, while it in males it was 18.9%, 2.6%, 17.1% and 13.6%, respectively. At histopathology, no increases in tumor incidence were attributed to treatment with cyadox. The mild swelling and fatty degeneration in hepatocytes, and mild swelling and tubular necrosis in the kidney were observed in 2000 mg/kg group. The no-observed-effect-level (NOEL) for carcinogenicity of cyadox fed to rats was 2000 mg/kg diet (132.18–156.28 mg/kg b.w./day). In conclusion, cyadox was not carcinogenic to rats with the liver and kidney as the target organs, and the side chain may be involved in toxicity and carcinogenicity mediated by QdNOs.     

在五年制护理专业计算机教学中实施NIT的体会

计算机教学是现代信息社会对职业教育的基本要求,是学生素质教育的重要组成部分,通过在五年制高职护理专业计算机教学改革中的实践,对计算机教学与全国计算机应用技术证书考试（NIT）的有机结合谈一点体会。     

Benzodiazepines medazepam and midazolam are activators of pregnane X receptor and weak inducers of CYP3A4: Investigation in primary cultures of human hepatocytes and hepatocarcinoma cell lines

Benzodiazepines have wide-spread used in pharmacotherapy for their anxiolytic, myorelaxant, hypnotic, amnesic and anticonvulsive properties. Despite benzodiazepines are used in clinics over 50 years, they have not been surprisingly tested for capability to induce major drug-metabolizing cytochromes P450. In the current study, we have examined the potency of Alprazolam, Bromazepam, Chlordiazepoxide, Clonazepam, Diazepam, Lorazepam, Medazepam, Midazolam, Nitrazepam, Oxazepam, Tetrazepam and Triazolam to induce CYP1A2 and CYP3A4 in primary cultures of human hepatocytes. Benzodiazepines were tested in therapeutic concentrations and in concentrations corresponding to their plasma levels in intoxicated patients. We found weak but significant induction of CYP3A4 mRNA by Midazolam and Medazepam, while other benzodiazepines did not induce CYP3A4 expression. None of the tested compounds induced CYP1A2 mRNA in three independent human hepatocytes cultures. In addition, employing gene reporter assays with transiently transfected hepatocarcinoma cells, we found that tested benzodiazepines did not activate aryl hydrocarbon receptor (AhR), whereas Midazolam and Medazepam slightly activated pregnane X receptor (PXR). Consistently, two-hybrid mammalian assay using hybrid fusion plasmids GAL4-PXR ligand-binding domain (LBD) and VP16-SRC-1-receptor-interacting domain (RID) confirmed PXR activation by Midazolam and Medazepam. In conclusion, Alprazolam, Bromazepam, Chlordiazepoxide, Clonazepam, Diazepam, Lorazepam, Nitrazepam, Oxazepam, Tetrazepam and Triazolam can be considered as safe drugs in term of their inability to induce PXR- and AhR-dependent cytochrome P450 enzymes CYP1A2 and CYP3A4. Medazepam and Midazolam slightly activated pregnane X receptor and displayed weak potency to induce CYP3A4 mRNA in human hepatocytes.