Measurement of glucose and fructose in clinical samples using gas chromatography/mass spectrometry

Objective:The impact of increased fructose consumption on carbohydrate metabolism is a topic of current interest, but determination of serum level has been hindered due to low concentration and interference from serum glucose. We are reporting a method for the quantification of glucose and fructose in clinical samples using gas chromatography/mass spectrometry (GC/MS). The accuracy and precision of GC/MS and an enzymatic assay were compared.Design and methods:Mass spectrometry fragmentation patterns of methyloxime peracetate derivatized aldose and ketose were determined. Unique fragments for glucose and fructose were used for quantitative analysis using isotope labeled recovery standards.Results:Methyloxime peracetate derivatives of glucose and fructose showed characteristic loss of acetate (M-60) or ketene (M-42) under chemical ionization (CI). Under electron impact (EI) ionization, a unique C1–C2 fragment of glucose was formed, while a C1–C3 fragment was formed from keto-hexoses. These unique fragments were used in the quantitative assay of glucose and fructose in clinical samples. In clinical samples, the GC/MS assay has a lower limit of detection than that of the enzymatic assay. In plasma samples from patients evaluated for diabetes the average serum glucose and fructose were 6.19 ± 2.72 mM and 46 ±  25.22 μM. Fructose concentrations in many of these samples were below the limit of detection of the enzymatic method.Conclusion:Derivatization of aldose and ketose monosaccharides to their respective O-methyloxime acetates for GC/MS analysis is a facile method for determination of serum/plasma glucose and fructose samples.     

Tetracosactrin vs. methylprednisolone in the prevention of emesis in patients receiving FEC regimen for breast cancer

0.5 mg tetracosactrin is considered to be equivalent to 40 mg methylprednisolone with regard to the induced cortisol secretion. 97 female breast cancer patients who received their first two FEC courses (epirubicin 50–75 mg/m², 5-fluorouracil 500 mg/m², cyclophosphamide 500 mg/m²) entered this randomised crossover study (76 had previously received an adjuvant treatment); tetracosactrin was administered intramuscularly and methylprednisolone intravenously immediately before chemotherapy administration. The tolerability was evaluated using a diary card during 5 days and patients were asked for their preference at the end of the two cycles. There was no difference either for vomiting (dry heaves were included) or nausea between the two treatments (the analysis was performed on day 1, the worse day of days 2 and 3 and the worse day of days 4 and 5). At day 1, 49% of the patients experienced no or mild nausea after tetracosactrin and 62% after methylprednisolone (not significant) (first period analysis); a complete control of vomiting (including dry heaves) was observed in 49% of the patients after tetracosactrin and 53% after methylprednisolone (not significant). No difference was observed between patients with or without previous chemotherapy. However, slightly more patients preferred tetracosactrin (P = 0.048).     

长链非编码RNA在恶性肿瘤中生物学作用的研究进展

长链非编码RNA（1ncRNA）是一类没有或很少具有开放阅读框架的、不能或极少编码蛋白质的RNA。近年来研究发现lncRNA在恶性肿瘤中有显著的组织特异性,并且在恶性肿瘤的临床诊断及预后判断中可能发挥重要作用。     

Electroacupuncture for the prevention of postoperative gastrointestinal dysfunction in patients undergoing vascular surgery under general anesthesia: study protocol for a prospective practical randomized controlled trial

BACKGROUND: Postoperative gastrointestinal dysfunction(PGD) is one of the most common complications following major surgeries under general anesthesia(GA). Despite ongoing research and new drug treatments, abdominal distension within 24 h postoperatively occurs in 8%–28% of all surgeries. We aim to analyze the effectiveness of preventing PGD by preoperatively stimulating Neiguan(PC6), Zusanli(ST36) and Shangjuxu(ST37) bilaterally twice a day compared with sham-acupuncture treatment and standard treatment.METHODS AND DESIGN: This is a single-center, prospective practical randomized controlled trial. All groups will be given standard treatments. Patients undergoing vascular surgery under GA will be included from the Vascular Surgery Unit in West China Hospital of Sichuan University, China, and divided into three groups. The experimental group will receive routine treatments and acupuncture at PC6, ST36 and ST37 bilaterally with electrical stimulation twice a day for 20 min preoperatively. The sham-acupuncture group will receive pseudo-electroacupuncture at sham acupoints of PC6, ST36 and ST37, which are 1 cun away from the real acupoints. The routine-treatment group will not receive electroacupuncture. The outcomes include the incidence of abdominal distention, abdominal circumference, the degree of abdominal distension, the fi rst time of fl atus and defecation, and hospitalization duration. DISCUSSION: The results from this study will demonstrate whether preoperative electroacupuncture is an effective method for the prevention of PGD in patients undergoing vascular surgery under GA. This study may also provide a standardized acupuncture treatment for reduction of PGD. TRIAL REGISTRATION: This study is registered with the Chinese Clinical Trial Registry: Chi CTR-TRC-13003649.     

咖啡酸苯一酯对人宫颈癌HeLa细胞的放射增敏作用

目的 探讨咖啡酸苯一酯(CAPE)对人宫颈癌HeLa细胞的放射增敏作用。方法 将宫颈癌HeLa细胞经不同浓度的CAPE作用24 h,四甲基偶氮唑盐比色法(MTT)法检测细胞抑制效应与CAPE浓度的关系。将HeLa细胞设对照组和药物组,两组均经⁶⁰Coγ射线照射0、2、4、6和8 Gy,计数细胞克隆;另将HeLa细胞设对照组、CAPE组、单纯照射组、照射+CAPE组,流式细胞检测技术分析CAPE对细胞周期的影响。结果 CAPE对HeLa细胞的抑制率呈剂量依赖性增加(F=126.49~3654.88,P<0.01);细胞经⁶⁰Coγ射线照射后,HeLa细胞克隆存活率随着照射剂量的增加而降低(F=174.42~9422.81,P<0.01);相同剂量下,药物组的HeLa细胞克隆存活率低于对照组(F=120.14~251.91,P<0.01);药物组和对照组HeLa细胞的平均致死剂量(D₀)为1.45和1.82 Gy、准阈剂量(D_q)为1.89和3.21 Gy, 药物组较小,放射增敏比(SER)为1.26>1;与对照组相比, CAPE组及单纯照射组G₂/M期的细胞比例升高(P<0.01),而在照射+CAPE组则降低(P<0.01)。结论CAPE通过对人宫颈癌HeLa细胞G₂/M期的阻滞及可能抑制细胞亚致死性损伤修复能力,发挥放射增敏作用。     

Homologous recombination is elevated in some Werner-like syndromes but not during normal in vitro or in vivo senescence of mammalian cells

Werner syndrome (WS) is a recessive genetic condition associated with markedly reduced replicative lifespans of cells in culture, high chromosomal instability in vivo and in vitro, and premature appearance of many characteristics of normal aging, including an increased incidence of cancer. We have monitored plasmid homologous recombination frequencies in diploid fibroblasts from 6 Werner or Werner-like syndrome patients, following transfection with a plasmid substrate containing 2 overlapping fragments of the TN5 Neo^r gene. Plasmid DNA recovered from these cells was then assayed for homologous recombination by (a) transformation of recA⁻ bacteria to Amp^r (indicating total viable plasmid) or Neo^r (indicating viable recombinant plasmid), and (b) by limited-cycle polymerase chain reaction (PCR) to co-amplify a recombinant fragment containing the overlap region, and a control region of the same plasmid, without bacterial transformation. Bacterial assay data indicated that recombination rates in 3 of the 6 WS strains were significantly elevated above normal controls; 4 of 6 appeared elevated by PCR assay. The highest-recombination WS strain showed evidence of reduced degradation of transfected plasmid DNA. For this small sample of WS strains, clinical severity of WS was not well correlated with recombination rate as determined by either assay (Pearson r=0.78, not significant, for PCR assay); elevated recombination may, however, define a subset of WS at greatest risk for cancer and/or atherosclerosis. PCR assay of a hyperoxia-resistant HeLa cell line, displaying substantially increased chromosome breakage, indicated increased recombination between direct-repeat fragments. Nevertheless, elevated recombination in WS strains is unlikely to be secondary to impaired replicative capacity characteristic of WS cells, or to defective repair of chromosome damage which is increased in WS, since recombination in non-WS strains was unaffected by passage level or repeated UV irradiation.