Breath-by-breath measurement of exhaled ammonia by acetone-modifier positive photoionization ion mobility spectrometry via online dilution and purging sampling / 药物分析学报

Exhaled ammonia(NH3)is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH3 with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH3 product ion peak of(C3H6O)4NH4+(K0=1.45 cm2/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C3H6O)2H+(K0=1.87 cm2/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH3 qualitative identification.Moreover,the interference of high humidity and the memory effect of NH3 molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92 μmol/L with a response time of 40 ms was achieved,and the exhaled NH3 profile could be synchronized with the concentration curve of exhaled CO2.Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH3 of healthy subjects,demon-strating its great potential for clinical disease diagnosis.

Development of Unidirectional Negative Corona Discharge Ion Mobility Spectrometer for Detection of Explosives / 分析化学

Abstract Ion mobility spectrometry ( IMS) based explosives detectors is wieldy deployed at the check points of airport, etc, so the development of new ionization method to replace the radioactive 63 Ni ion source in IMS is highly demanded. In this study, a novel negative corona discharge was developed for ion mobility spectrometer for rapid detection of trace explosives, which was running in the unidirectional mode to efficiently remove nitrogen oxides and ozone produced from the discharge process. The diameter of target electrode was 3 mm, the distance between the needle and the target electrode was 2 mm, the discharge voltage was 2400 V and the flow rate of drift gas was 1200 mL/min. Under the optimized conditions, the dominant reactant ions was O-2(H2O)n and could be used to directly detect the common explosives, such as trinitrotoluene (TNT), ammonium nitrate (AN), nitroglycerin (NG), pentaerythritol tetranitrate (PETN) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The limit of detection of TNT was 200 pg/μL. These results indicated that negative corona discharge ionization source, with the advantanges of the high sensibility, simple structure and no radioactivity, could be used as a potential and promising ionization source for ion mobility spectrometry to detect explosives.

Effects of Ginsenosides Rg3 on Vasculogenic Mimicry of Pancreatic Cancer Xenograft / 医学研究杂志

Objective To investigate the effects of ginsenosides Rg 3 on vasculogenic mimicry of pancreatic cancer xenograft through the establishment of pancreatic cancer cell line SW -1990 subcutaneous xenograft model .Methods After pancreatic cancer xenograft in nude mice model beening established , All the mice were randomly divided into 4 groups and treated intraperitoneally ( IP) with saline and various concentrations (5,10,20 mg/kg) of ginsenosides Rg3.To observe the effect of ginsenoside Rg3 on tumor growth.Immunohisto-chemical-PAS staining was used to detect the effects of ginsenosides Rg 3 on vasculogenic mimicry of pancreatic cancer xenograft .and mRNA and protein expression of MMP 2、MMP9 were respectively evaluated by FQ -PCR and Western blot .Results The ginsenosides Rg3 can inhibit the growth of the tumor xenografts in nude mice .The inhibitory effect is the most obvious the 20 mg/kg of ginsenosides Rg3 group.The expression of MMP-2, MMP-9 were down-regulated compare with the control group , and the difference was signifi-cant;the Immunohistochemical -PAS staining showed the number of vasculogenic mimicry (+) and CD31 (+) were less than that in the control group .Conlusion Our results demonstrate that pancreatic vascular mimicry formation can be suppressed by Ginsenoside Rg 3 though reducing the expression of MMP -2, MMP-9 in our vivo experiments ,

Clinicopathological significance of PTPN12 expression in human breast cancer

Protein tyrosine phosphatase non-receptor type 12 (PTPN12) is a recently identified tumor suppressor gene (TSG) that is frequently compromised in human triple-negative breast cancer. In the present study, we investigated the expression of PTPN12 protein by patients with breast cancer in a Chinese population and the relationship between PTPN12 expression levels and patient clinicopathological features and prognosis. Additionally, we explored the underlying down-regulation mechanism from the perspective of an epigenetic alteration. We examined PTPN12 mRNA expression in five breast cancer cell lines using semi-quantitative reverse-transcription PCR, and detected PTPN12 protein expression using immunohistochemistry in 150 primary invasive breast cancer cases and paired adjacent non-tumor tissues. Methylation-specific PCR was performed to analyze the promoter CpG island methylation status of PTPN12. PTPN12 was significantly down-regulated in breast cancer cases (48/150) compared to adjacent noncancerous tissues (17/150; P < 0.05). Furthermore, low expression of PTPN12 showed a significant positive correlation with tumor size (P = 0.047), lymph node metastasis (P = 0.001), distant metastasis (P = 0.009), histological grade (P = 0.012), and survival time (P = 0.019). Additionally, promoter CpG island hypermethylation occurs more frequently in breast cancer cases and breast cancer cell lines with low PTPN12 expression. Our findings suggest that PTPN12 is potentially a methylation-silenced TSG for breast cancer that may play an important role in breast carcinogenesis and could potentially serve as an independent prognostic factor for invasive breast cancer patients.

The Hippo pathway regulates stem cell proliferation, self-renewal, and differentiation

Stem cells and progenitor cells are the cells of origin for multi-cellular organisms and organs. They play key roles during development and their dysregulation gives rise to human diseases such as cancer. The recent development of induced pluripotent stem cell (iPSC) technology which converts somatic cells to stem-like cells holds great promise for regenerative medicine. Nevertheless, the understanding of proliferation, differentiation, and self-renewal of stem cells and organ-specific progenitor cells is far from clear. Recently, the Hippo pathway was demonstrated to play important roles in these processes. The Hippo pathway is a newly established signaling pathway with critical functions in limiting organ size and suppressing tumorigenesis. This pathway was first found to inhibit cell proliferation and promote apoptosis, therefore regulating cell number and organ size in both Drosophila and mammals. However, in several organs, disturbance of the pathway leads to specific expansion of the progenitor cell compartment and manipulation of the pathway in embryonic stem cells strongly affects their self-renewal and differentiation. In this review, we summarize current observations on roles of the Hippo pathway in different types of stem cells and discuss how these findings changed our view on the Hippo pathway in organ development and tumorigenesis.

Optimization of attachment conditions for rabbit mesenchymal stem cells in cytodex 3 microcarrier culture systems / 生物医学工程学杂志

Mesenchymal stem cells are of great value in tissue engineering and genetic engineering. To study the in vitro dynamic expansion of mesenchymal stem cells by microcarrier technology, we began the research with the investigation of attachment of rabbit mesenchymal stem cells on cytodex 3 microcarriers after inoculation. The result showed a poor attachment efficiency of 16.7% +/- 1.1% under general conditions, so the attachment efficiency must be increased through the optimization of inoculation conditions. Intermittent stirring, inoculation in 50% of the final culture volume and reduction of the fetal bovine serum concentration at inoculation all led to notable increases in attachment efficiency. Ratio of rMSCs attached in aMEM cultures was 39.8% higher than that of DMEM's on the average. When all these optimal conditions were adopted, the attachment efficiency (65.5%) was significantly higher than that (26.6%) under general conditions; accordingly the final growth extents of rMSCs were 4. 50 and 2. 01, respectively. Therefore, the optimization of attachment conditions promoted the expansion of rMSCs on microcarriers.