Iranian Biomedical Journal
Volume:12 Issue: 3, jul 2008

Adipose-derived stem cells (ADSC) could be an appealing alternative to bone marrow stem cells (BMSC) for engineering cell-based osteoinductive grafts. Meanwhile, prior studies have demonstrated that melatonin can stimulate osteogenic differentiation. Therefore, we assayed and compared the melatonin effect on osteogenic differentiation of BMSC with that of ADSC. Mesenchymal stem cells (MSC) were isolated from the bone marrow and fat of adult rats. Both cell types were cultured in osteogenic medium in the absence and presence of melatonin at physiological concentrations (20-200 pg/ml). After 4 weeks, the expression of osteocalcin gene was analyzed by reverse transcription-PCR, alkaline phosphatase (ALP) activity was assayed and alizarin red S and von Kossa staining were done. Cell viability and apoptosis were also assayed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, a tetrazole (MTT) and flow cytometry, respectively. The osteoblastic differentiation of ADSC as demonstrated by ALP activity was less than that of BMSC. The amount of matrix mineralization has shown by alizarin red S and von Kossa staining also showed statistical differences between the two MSC. The incidence of apoptotic cells was higher among ADSC than BMSC. The flow cytometry proves that cell growth reduction is due to a decrease in the number of the cells entering the S phase of the cell cycle. MTT assay indicated that viable cells were fewer among ADSC than BMSC in control groups. The results of the study suggest that BMSC have greater osteogenic potential than ADSC and that melatonin promotes osteogenic differentiation to BMSC, but has a negative effect on ADSC osteogenic differentiation

High levels of rheumatoid factors (RF) are detectable in serum of the majority of patients with rheumatoid arthritis (RA), but 5-10% of patients remain seronegative (SN). Despite clinical and genetic similarities between these two subsets of RA, it has been proposed that they may be regarded as distinct clinical entities. In the present study a panel of monoclonal antibodies (mAb) recognizing RF-associated cross-reactive idiotypes (CRI) linked to the VH1 (G8), VH4 (LC1), VK3b (17-109) and a mAb recognizing the VK3 subgroup (C7) of immunoglobulin variable region (IgV) gene products were used to quantitate the level of expression of these gene products in serum and synovial fluid of 35 seropositive (SP) and 8 SN RA patients by capture ELISA. While the concentration and relative proportion of the IgV are recognized by the mAb G8, 17-109 and C7 were significantly higher in serum and synovial fluid of the SP RA, compared to the SN-RA patients (G8, p = 0.009; 17-109, p = 0.0001; C7, p = 0.001). The CRI recognized by the mAb LC1 was highly represented in serum and synovial fluid of the SN-RA patients. There have been no significant differences in the level of expression of these IgV gene products (other than the product recognized by C7 mAb in SP patients) between serum and synovial fluid of either group of patients. Our results suggest that the expressed repertoire of Ig VH and VK genes in these two subsets of RA is differentially regulated and may be influenced by selective mechanisms leading to positive or negative selection of certain genes

Integrins are a family of transmembrane proteins that allow communication between the extracellular matrix and the interior of cells. Chondrocytes, cells of articular cartilage, express integrins and these molecules appear to have a variety of roles including mechanotransduction. Integrins are known to associate with a number of accessory molecules such as CD147 that may act to regulate their activity. The purpose of this study was to investigate the expression of CD147 in normal and osteoarthritis human articular cartilage and identify potential roles in mechanical signalling. Expression of CD147 in normal and osteoarthritis human articular cartilage was examined by the immunostaining and Western-blotting techniques. Potential roles in mechanotransduction were studied by assessing effects of function blocking antibodies on the electrophysiological response to mechanical stimulation. CD147 was extensively expressed by chondrocytes in normal and osteoarthritic cartilage and shown by Western-blotting to have a molecular weight in the region of 35-50 kDa. Function blocking antibodies had no effect on the membrane depolarisation response of chondrocytes from osteoarthritic cartilage to mechanical stimulation. Human articular chondrocytes show extensive expression of CD147 in normal and osteoarthritic cartilage. Roles for this molecule in regulation of chondrocyte function remain to be defined

The virulence of a pathogenic Vibrio cholerae is dependent on a discrete set of genetic determinants. In this study, we determined the distribution of virulence determinants among the clinical and environmental isolates of V. cholerae. The antibiotic resistance profiles of the isolates were determined using standard disk diffusion assay. PCR assay was performed to analyze the presence of toxin genes of ctx, zot and ace. The composition of cholera toxin encoding element (CTX) region flanking of the V. cholerae isolates was also analyzed. All of the clinical isolates (100%) showed a complete set of virulence genes and also the attachment site of the filamentous bacteriophage CTX. None of the environmental isolates contained the virulence genes and the attachment site of the CTX. Analysis of the flanking regions including the toxin-linked cryptic element and repeat in toxin genes revealed their integrity in the clinical isolates while in the environmental isolates they were absent or contained incomplete sequences. Comparison of the antibiotic resistance assay of the environmental and clinical isolates showed a significant difference in the resistance profiles of the isolates obtained from the two sites. High rates of resistance to co-trimoxosol, streptomycin and chloramphenicol were found with clinical isolates. The absence of all virulence determinants in the environmental strains may suggest that certain ecological features must be present for V. cholerae to acquire a complete set of virulence determinants and to turn them into pathogenic strains

Pectic acid extracted from plants increases the secretion of prolactin (PRL) when injected intravenously into ewes or fed to rats. Fragments of ewe hypophysis and lactating rabbit mammary gland incubated in vitro in the presence of pectic acid secreted more PRL and caseins compared to the controls. However, it is not known whether pectic acid directly stimulates PRL secretion in pituitary or interference of factors from hypophysis is required for this process. GH3/B6 cells, a clonal strain of rat pituitary, were cultured and incubated with pectic acid (2.5-100 µg/mL). The integrity of cells was examined under pectic acid treatment microscopically. Controls or pectic acid treated cells were assayed for their ability to produce PRL. The PRL was assayed by Western-blotting and Radioimmunoassay. pectic acid did not have any significant effect on the viability of cells. After being incubated with pectic acid, the cells started to become circular and protuberant shape. The maximum stimulation and PRL secretion occurred at 100 µg/mL concentration within 30 min of incubation with pectic acid. pectic acid could stimulate the release of PRL in GH3/B6 cells in the short-term incubation. This result suggested that pectic acid is a non-toxic agent that could directly stimulate PRL secretion in pituitary cells without any interference of hypophysis

Thiamine (VitB1) is a vitamin with various important physiological functions and postulated therapeutic effects. Its use as an analgesic in neuropathic pain has been undergoing in clinical settings. However, there has been little experimental investigation on this effect. In this study, anti-nociceptive and anti-inflammatory effects of thiamine were investigated in mice. Three doses of thiamine (50, 100 and 125 mg/kg) were used by intraperitoneal injection in this study. Acute and chronic anti-nociceptive effects were examined using hot plate test alone and after sciatic nerve ligation, respectively. Imipramine (40 mg/kg) was used as positive control. Anti-inflammatory effects of thiamine on acute and chronic inflammation were assessed using xylene-induced edema in ears and granuloma caused by compressed cotton implantation, respectively. Sodium diclofenac (15 mg/kg) was used as positive control. Open field test was performed to differentiate the mice responses in the acute anti-nociceptive tests. All three doses of thiamine showed significant analgesic effects in non-ligated mice and also in neuropathic pain in ligated animals. Increasing the dose of thiamine correlated with a more pronounced and sustained effect. Acute anti-inflammatory investigation showed that thiamine injected 30 or 60 minutes before xylene application reduced the weight of edematic ears. However, the effect of thiamine was less pronounced than diclofenac. Furthermore, when injected once daily for 7 days, all doses of thiamine significantly reduced the weight of the cotton disks, showing suppression of granuloma formation. Taken together, it has been shown that thiamine possesses remarkable analgesic activities and also has significant anti-inflammatory effects, confirming its clinical use in controlling pain and less in inflammation

The assessment of altered nitric oxide (NO) availability is of potentially important diagnostic and prognostic significance. The present study is aimed to investigate the effect of L-arginine (as a natural NO donor) supplementation on NO metabolite in a rabbit model of hypercholesterolemia to find a reliable marker for endothelial NO production. White male rabbits (n = 30) randomly assigned to 2 groups. Rabbits were fed 1% high-cholesterol diet (HC group, n = 15), or HC diet with oral L-arginine (3% in drinking water) (HC + L-arginine group, n = 15) for 4 weeks. The serum levels of lipids, L-arginine, total NO metabolites (NOx), nitrite and nitrate were measured before and after the study. In this study, L-arginine supplementation led to a significant increased plasma level of L-arginine. The serum level of nitrite was significantly higher in L-arginine treated group while serum level of nitrate and NOx was significantly lower than HC group. As the result of our study showed, nitrite is a useful marker of endogenous endothelial NO production and although frequently used, neither nitrate nor NOx are reliable markers of acute changes in endothelial NO synthase activity

During the last decade, enterococci have become important nosocomial pathogens, representing the second leading cause of urinary tract infections. This increasing prevalence has been paralleled by the occurrence of multi-drug resistant (MDR) and high-level gentamicin resistant (HLGR) strains. From September 2005 to 2006, a total of 638 enterococcal isolates were collected from urine samples among 9 medical centers in Tehran (Iran). Confirmation of species and detection of gentamicin resistance genes were done by PCR method. Anti-microbial susceptibility test was determined with disk diffusion and minimal inhibitory concentration of gentamicin among HLGR isolates assayed by microdilution methods. The isolates were found to consist of Enterococcus faecalis (77.8%) and Enterococcus faecium (22.2%). The results obtained from PCR showed a high rate of agreement with phenotypic assays for both species. MDR to most prevalent anti-microbials was present in 29% and 72% of the E. faecalis and E. faecium isolates, respectively. HLGR phenotype was detected in 64% of E. faecalis and 92% of E. faecium isolates. The aac(6'')-Ie-aph(2")-Ia gene were identified in 83% of E. faecalis and 100% of E. faecium HLGR isolates. E. faecalis and E. faecium isolates differed in their susceptibilities to different antibiotics. Emergence of multi-resistant enterococci and high level resistance to gentamicin shown by enterococcal strains is of concern because of the decrease in the therapeutic options for treatment of infections caused by enterococci

Asthma is a chronic inflammatory disorder of the airways. The available treatment options have major limitations owing to low efficacy, associated adverse events and compliance issues. Therefore, the health burden of bronchial asthma is increasing globally at an alarming rate, providing a strong impetus for the development of new therapeutics. Myrica sapida is known traditionally in Ayurveda to possess anti-asthmatic activity. Hence, the present investigation was undertaken to evaluate the bronchodilator and anti-anaphylactic activity of the stem bark of Myrica sapida. Experimental models studied were acetylcholine induced bronchospasm in guinea pigs, egg albumin induced anaphylaxis in guinea pigs, in vitro studies on tracheal strip of egg albumin sensitized guinea pigs. Treatment with ethanolic extract of M. sapida, 75 mg/kg, orally resulted in significant protection against acetylcholine aerosol induced bronchospasm and allergen induced anaphylaxis in guinea pigs. Ethanolic extract of M. sapida (75 mg/kg, p.o.) prevented the potentiation of responses and also produced a decrease in pD2 value of histamine and acetylcholine in guinea pig tracheal strip. These results suggest that M. sapida possesses bronchodilator activity, has potent inhibitory effect on immediate hyper-sensitivity reactions and decreases bronchial hyper-responsiveness