Stem Cell Tracing Through MR Molecular Imaging

Stem cell therapy opens a new window in medicine to overcome several diseases that remain incurable. It appears such diseases as cardiovascular disorders, brain injury, multiple sclerosis, urinary system diseases, cartilage lesions and diabetes are curable with stem cell transplantation. However, some questions related to stem cell therapy have remained unanswered. Stem cell imaging allows approval of appropriated strategies such as selection of the type and dose of stem cell, and also mode of cell delivery before being tested in clinical trials. MRI as a non-invasive imaging modality provides proper conditions for this aim. So far, different contrast agents such as superparamagnetic or paramagnetic nanoparticles, ultrasmall superparamagnetic nanoparticles, fluorine, gadolinium and some types of reporter genes have been used for imaging of stem cells. The core subject of these studies is to investigate the survival and differentiation of stem cells, contrast agent's toxicity and long term following of transplanted cells. The promising results of in vivo and some clinical trial studies may raise hope for clinical stem cells imaging with MRI.

[Synthesis of gold nanoparticles and study of their antimicrobial effects study on Helicobacter pylori]

Helicobacter pylori is a helix-shaped, gram-negative and microaerophilic bacterium. This bacterium is one of the main causes of peptic ulcer disease. Nowadays, multidrug therapy is used to eliminate the bacterium. Unfortunately, drug resistance to these drugs has difficulty in the treatment. The use of nanotechnology in medicine can be the solution of this problem in the future. Among nanometals, gold nanoparticles have exclusive features, which can be used in medical applications. Therefore, this study aimed to investigate the effect of gold nanoparticles on the Helicobacter pylori isolates, which are sensitive or resistant to conventional drugs. Firstly, the gold nanoparticles were synthesized by Turkevich method, and then, spectroscopic and electron microscopic characteristics were analyzed. Anti H. pylori activity of pure gold nanoparticles was determined using disk diffusion method according to CLSI standards. The size of gold nanoparticles was 10-12 nm and the maximum wavelength of the nanoparticles was obtained to be 522 nm. In the disk diffusion method, no inhibition zone was observed around gold nanoparticles discs for susceptible and resistant isolates. Findings of this study showed that low concentrations of gold nanoparticles has no effect on Helicobacter pylori isolates

Lower circulating levels of chemokine CXCL10 in Helicobacter pylori- infected patients with peptic ulcer: influence of the bacterial virulence factor CagA

Alterations in CXCL10 [a Th1 chemokine] expression have been associated with various diseases. The aim of this study was to evaluate the serum CXCL10 levels in H. pylori- infected patients with peptic ulcer [PU], H. pylori- infected asymptomatic [AS] subjects and healthy H. pylori-negative subjects, and also to determine its association with bacterial virulence factor cytotoxin-associated gene A [CagA]. Serum samples from 90 H. pylori infected patients with PU [70 were anti-CagA[+], 20 were anti-CagA[-]], 65 AS carriers [40 were anti-CagA[+], 25 were anti-CagA[-]] and 30 healthy H. pylori-negative subjects [as a control Group] were tested for concentrations of CXCL 10 by using the ELISA method. The mean serum levels of CXCL10 in PU patients [96.64 +/- 20.85 pg/mL] were significantly lower than those observed in AS subjects [162.16 +/- 53.31 pg/mL, P < 0.01] and the control group [193.93 +/- 42.14 pg/mL, P < 0.02]. In the PU group, the serum levels of CXCL10 in anti-CagA[+] subjects was significantly higher in comparison to anti-CagA[-] patients [P < 0.04]. These results showed that the mean concentrations of CXCL10 in H. pylori-infected-PU patients was lower than AS carriers and control group. In the PU group, the serum levels of CXCL10 were associated with bacterial factor CagA

IL-10, TNF-alpha and IFN-gamma levels in serum and stomach mucosa of helicobacter pylori-infected patients

H. pylori is a human pathogen that colonizes the epithelium of the stomach. The host immune response may influence the disease process, where cytokines play important roles in the development of disease. In this study, the concentrations of selected cytokines in the gastric antrum and stomach body mucosa and also in the serum were evaluated. Eighty patients according to their rapid urease test were divided into two groups: H. pylori positive [n=39] and H.pylori-negative [n=41]. The concentrations of cytokines in biopsies and serum were determined by ELISA method. The mean TNF-alpha and IFN-gamma levels in the infected group were significantly higher than that of uninfected patients. In contrast, IL-10 level in most patients was undetectable. The mean antral of stomach TNF-alpha and IFN-gamma levels were significantly higher than that of the stomach body. IFN-gamma serum level showed positive correlation with antrum and stomach body levels, whereas no correlation was found in TNF-alpha in different samples. Higher levels of TNF-alpha and IFN-gamma in antral indicate that the colonization of bacteria in the antrum may be higher than stomach body [culture results from two sites support this statement]. Increased serum level of IFN-gamma indicates the activation of circulating-T cells against infection. Induced H. pylori-related TNF-alpha is concentrated is gastric mucosa and this pathogen does not cause any significant change in the serum level of this cytokine. Therefore H. pylori by inducing certain inflammatory cytokines but not IL-10 may contribute the process of disease development

Detection of A2142C, A2142G, and A2143G mutations in 23s rRNA gene conferring resistance to clarithromycin among Helicobacter pylori isolates in Kerman, Iran

Clarithromycin resistance in Helicbacter pylori has been found to be associated with point mutations in 23s rRNA gene leads to reduced affinity of the antibiotic to its ribosomal target or changing the site of methylation. The aim of this study was to determine the most important point mutations in 23s rRNA gene in H. pylori that are closely related to clarithromycin resistance among such isolates. Sixty three H. pylori isolates, obtained from gastric biopsy speciemens in Kerman, Iran, were used to evaluate their susceptibility to clarithromycin by disk diffusion test, and to detect the most common point mutations in 23s rRNA gene associated with clarithromycin resistance by Polymerase chain reaction-amplification and restriction fragment length polymorphism [PCR-RFLP] and 3'-mismatch PCR. 31.7% of the H. pylori isolates were resistant to clarithromycin, and each of the resistant isolate had at least one of the most common point mutations in 23s rRNA gene associated with calrithromycin resistance. According to our results three common point mutation in 23s rRNA gene in H. pylori are closely related to clarithromycin resistance. There was an absolute relation between 23s rRNA gene point mutations and clarithromycin resistance in this study. Helicbacter pylori resistance to clarithromycin can cause failure in the eradications of the bacteria. The resistance of the bacteria is expanding in most parts of the world including Iran