Inducible nitric oxide synthase (iNOS) expression in monocytes during acute Dengue Fever in patients and during in vitro infection

 

Mononuclear phagocytes are considered to be main targets for Dengue Virus (DENV) replication. These cells are activated after infection, producing proinflammatory mediators, including tumour-necrosis factor-α, which has also been detected in vivo. Nitric oxide (NO), usually produced by activated mononuclear phagocytes, has antimicrobial and antiviral activities.

Methods

The expression of DENV antigens and inducible nitric oxide synthase (iNOS) in human blood isolated monocytes were analysed by flow cytometry using cells either from patients with acute Dengue Fever or after DENV-1 in vitro infection. DENV-1 susceptibility to iNOS inhibition and NO production was investigated using N^G-methyl L-Arginine (N^GMLA) as an iNOS inhibitor, which was added to DENV-1 infected human monocytes, and sodium nitroprussiate (SNP), a NO donor, added to infected C6/36 mosquito cell clone. Viral antigens after treatments were detected by flow cytometry analysis.

Results

INOS expression in activated monocytes was observed in 10 out of 21 patients with Dengue Fever and was absent in cells from ten healthy individuals. DENV antigens detected in 25 out of 35 patients, were observed early during in vitro infection (3 days), significantly diminished with time, indicating that virus replicated, however monocytes controlled the infection. On the other hand, the iNOS expression was detected at increasing frequency in in vitro infected monocytes from three to six days, exhibiting an inverse relationship to DENV antigen expression. We demonstrated that the detection of the DENV-1 antigen was enhanced during monocyte treatment with N^GMLA. In the mosquito cell line C6/36, virus detection was significantly reduced in the presence of SNP, when compared to that of untreated cells.

Conclusion

This study is the first to reveal the activation of DENV infected monocytes based on induction of iNOS both in vivo and in vitro, as well as the susceptibility of DENV-1 to a NO production.     

云南恶性疟原虫氯喹抗药性基因76位点突变研究

目的研究云南恶性疟原虫氯喹抗药性基因（pfcrt）76位点突变的情况,以及与抗药性表现型的关系. 方法应用PCR和限制性酶切片段长度分析方法,检测现症病人干滤纸血样的恶性疟原虫pfcrt基因点突变. 结果 云南省恶性疟原虫pfcrt基因76位点的突变型很高,占85.0%（51/60）;野生型和混合型较少,分别占8.3%（5/60）和6.7%（4/60）.体内法测定的氯喹抗性和敏感样本均有pfcrt76突变型;体外法测定的17份氯喹抗性样本中,有13份带有pfcrt76突变型. 结论 云南省恶性疟原虫pfcrt基因氨基酸编码76位点突变频度很高.体内和体外法测定的氯喹抗性表现与pfcrt76突变型有较高的一致性.     

A colony assay for in vitro transformation by human T cell leukemia viruses type I and type II

We report here the development of a rapid and quantitative method for measuring in vitro T cell transformation by human T cell leukemia viruses type I (HTLV-I) and type II (HTLV-II). This method is based on our finding that cocultivation of lethally irradiated HTLV-producing cells with peripheral blood lymphocytes (PBLs) preactivated for 24 hours with phytohemagglutinin and interleukin-2 (IL-2) induces colony formation in methylcellulose-containing medium. Colonies of about 200 cells can be clearly distinguished from background aggregates within four to six days after cocultivation. These colonies gradually increase in size and reach 300 to 1,000 cells within 14 days after cocultivation. Cells of these colonies were infected, as evidenced by expression of viral p19 antigen and the presence of HTLV proviral sequences. These cells proved to be transformed in terms of IL-2- independent continuous growth in liquid medium. Colony formation was found to depend in a linear fashion upon the percentage of the infected cells present in the irradiated cell population and is sufficiently sensitive to detect as few as 1% of virus-producing cells.     

Spiral-shaped biliary endoprosthesis: initial study

A new flexible, spiral-shaped biliary endoprosthesis is described. This spiral endoprosthesis can negotiate acute angles, can be cut to any length, and has been specifically designed to deal with the problem of stent migration. The authors report their initial experience with this endoprosthesis in 14 patients.     

Precise measurements of intrauterine vascular structures at hysteroscopy in menorrhagia and during Norplant use

Using currently available equipment for panoramic hysteroscopy, the size of images viewed cannot be accurately judged because of the magnifying and distorting effects of the objective lens. This study has demonstrated that magnification by the hysteroscope lens can alter the apparent size of images by up to 27%. An additional effect of lens distortion can alter the apparent size of images viewed by up to 28%, depending on the position of the image in the field of view. These effects are independent and may be additive. Thus, the apparent size of intrauterine structures at hysteroscopy may bear little resemblance to their actual size. Image-correction methods are described which reduce the effects of image magnification on the apparent size of an object viewed through the hysteroscope to 7%, and the effect of distortion to 3 %. This technique can greatly improve the accuracy of measurement at hysteroscopy, and has been utilized in this study for the precise measurement of superficial endometrial vascular diameter (mean+/-SEM) in 34 Norplant users (120+/-11.6 microm) and 20 women with spontaneous menorrhagia (74+/-7.2 microm). It has also confirmed the presence of scattered dilated vessels (up to 777 microm in diameter) on the endometrial surface in some Norplant users.      

云南省恶性疟原虫多药抗性基因Asn86Tyr多态性调查

目的检测云南恶性疟原虫多药抗性基因(Pfmdr1)Asn86Tyr的多态性,探索其与氯喹敏感性表现型的关系.方法用等位基因特异PCR和限制性酶切片段长度分析技术(AS-PCR/RFLP).结果在86%(19/22)的氯喹抗性分离株中检测到Pfmdr1基因的Asn86Tyr两种多态性,携带编码86Tyr多态变异的占50%,而含编码Asn86多态的也是50%.结论在云南氯喹抗性高度流行区,Pfmdr1基因Asn86Tyr的多态性是普遍存在的.