Human DNA Topoisomerase I (hTopo I) has been identified to be an efficient target of many effective antitumor drugs. Natural hTopo I is not convenient to be used in screening because of its low concentration in cells. In order to fast screen new anticancer drugs targeting at hTopo I from natural compounds in vitro, hTopo I gene open reading frame (ORF) has been successfully cloned and overexpressed in Pichia pastoris. Total RNA extracted from Hela cells was reversely transcripted to synthesize cDNA with the hTopo I specific antisense primer and the hTopo I ORF was synthesized by PCR. After digestion with EcoR I and Kpn I, the synthesized fragment was inserted into pPICZaA, gave rise to pPICZalpha-hTopoI. After digestion with Sac I, the lined pPICZalpha-hTopoI was transformed into Pichia pastoris strains (KM71, X33 and SMD1168) by electroporation and integrated into their genome. After screened on YPDS plates (containing 1000 ug/mL zeocin), the high-copy recombinant strains (KM-hTopoI, X33-hTopoI and SMD-hTopol) could overexpress recombinant hTopo I, which was fused to the alpha-factor secretion signal and could be secreted into the supernatant in the culture. alpha-factor could be cleaved from the expressed protein during secretion. A higher activity amount of the enzyme was secreted by the particular strain SMD-hTopoI because of its absence of proteimase A than by other strains which possess proteinase A activity. After optimizing the fermentation conditions, a relatively higher enzyme activity in the culture supernatant could be obtained when SMD-hTopoI was induced in BMMY (pH7.25) at 20 degrees C , with addition of 0.5% (V/V) methanol and 3% (V/V) nutrient liquid every 24h. The enzyme activity reached 43 000 u/mL, the yield reached 11 mg/L, achieving approximate 10% of total protein in the culture supernatant. SDS-PAGE and Western blot analyses showed that the mass of the recombinant hTopo I was 91 kD with no glycosylation.
DNA Topoisomerases, Type I ; biosynthesis ; genetics ; Fermentation ; Humans ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

BACKGROUNDProactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci (VRE) endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong.

METHODSWe described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing (MLST) was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE.

RESULTSBetween November 26 and December 17, 2011, 11 patients (1 exogenous case and 10 secondary cases) in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% (10/361). There were 8 males and 3 females with a median age of 78 years (range, 40 - 87 years). MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay (P < 0.001), a higher proportion with chronic cerebral and cardiopulmonary conditions (P = 0.001), underlying malignancies (P < 0.001), and presence of urinary catheter (P < 0.001), wound or ulcer (P < 0.001), and a greater proportion of these patients were receiving β-lactam/β-lactamase inhibitors (P = 0.009), carbapenem group (P < 0.001), fluoroquinolones (P = 0.003), or vancomycin (P = 0.001) when compared with the controls.

CONCLUSIONExtensive contact tracing and screening with a "search-and-confine" strategy was a successful tool for outbreak control in our healthcare region.

Aged ; Aged, 80 and over ; Enterococcus faecium ; growth & development ; pathogenicity ; Female ; Gram-Positive Bacterial Infections ; epidemiology ; prevention & control ; Hong Kong ; epidemiology ; Humans ; Male ; Middle Aged ; Vancomycin Resistance

OBJECTIVETo assess the biological effects of the six-herb mixture Anti-Insomia Formula (AIF) extract using caffeine-induced insomnia Drosophila model and short-sleep mutants.

METHODSCaffeineinduced insomnia wild-type Drosophila and short-sleep mutant flies minisleep (mns) and Hyperkinetic(Y) (Hk(Y)) were used to assess the hypnotic effects of the AIF in vivo. The night time activity, the amount of night time sleep and the number of sleep bouts were determined using Drosophila activity monitoring system. Sleep was defined as any period of uninterrupted behavioral immobility (0 count per minute) lasting > 5 min. Night time sleep was calculated by summing up the sleep time in the dark period. Number of sleep bouts was calculated by counting the number of sleep episodes in the dark period.

RESULTSAIF at the dosage of 50 mg/mL, effectively attenuated caffeine-induced wakefulness (P<0.01) in wild-type Canton-S flies as indicated by the reduction of the sleep bouts, night time activities and increase of the amount of night time sleep. AIF also significantly reduced sleeping time of short-sleep Hk(Y) mutant flies (P<0.01). However, AIF did not produce similar effect in mns mutants.

CONCLUSIONAIF might be able to rescue the abnormal condition caused by mutated modulatory subunit of the tetrameric potassium channel, but not rescuing the abnormal nerve firing caused by Shaker gene mutation. This study provides the scientific evidence to support the use of AIF in Chinese medicine for promoting sleep quality in insomnia.

Animals ; Caffeine ; Chromatography, High Pressure Liquid ; Disease Models, Animal ; Drosophila melanogaster ; drug effects ; physiology ; Hypnotics and Sedatives ; pharmacology ; therapeutic use ; Mutation ; genetics ; Potassium Channels ; genetics ; Sleep ; drug effects ; Sleep Initiation and Maintenance Disorders ; drug therapy ; Wakefulness ; drug effects

INTRODUCTION: An echocardiographic calcium score (ECS) predicts cardiovascular disease (CVD) in the general population. Its utility in peritoneal dialysis (PD) patients is unknown. METHODS: This cross-sectional study assessed 125 patients on PD. The ECS (range 0-8) was compared between subjects with CVD and those without. RESULTS: Among the subjects, 54 had CVD and 71 did not. Subjects with CVD were older (69 years vs. 56 years, P < 0.001) and had a higher prevalence of diabetes mellitus (DM) (81.5% vs. 45.1%, P < 0.001). They had lower diastolic blood pressure (72 mmHg vs. 81 mmHg, P < 0.001), lower phosphate (1.6 mmol/L vs. 1.9 mmol/L, P = 0.002), albumin (30 g/L vs. 32 g/L, P = 0.001), parathyroid hormone (34.4 pmol/L vs. 55.8 pmol/L, P = 0.002), total cholesterol (4.5 vs. 4.9, P = 0.047), LDL cholesterol (2.4 mmol/L vs. 2.8 mmol/L, P = 0.019) and HDL cholesterol (0.8 mmol/L vs. 1.1 mmol/L, P = 0.002). The ECS was found to be higher in subjects with CVD than in those without (2 vs. 1, P = 0.001). On multivariate analysis, only DM and age were independently associated with CVD. CONCLUSION The ECS was significantly higher in PD patients with CVD than in those without, reflecting a higher vascular calcification burden in the former. It is a potentially useful tool to quantify vascular calcification in PD patients.
Humans ; Cardiovascular Diseases/diagnostic imaging* ; Cross-Sectional Studies ; Calcium ; Peritoneal Dialysis/adverse effects* ; Vascular Calcification/epidemiology* ; Echocardiography