Iranian Journal of Basic Medical Sciences
Volume:13 Issue: 1, winter2010

The use of co-culture cells as well as extra cellular matrix are among those strategies that have been employed to direct mesenchymal stem cell (MSC) bone differentiation in culture. In this regard, there is no study considering the effects of Matrigel on mesenchymal stem cell (MSC) in vitro bone differentiation. This was the subject of the present study. Human passaged-3 MSCs isolated from the marrow aspirates were seeded on either Matrigel or conventional polystyrene plastic surfaces (as control) for 10 days. To compare the cell proliferation in two cultures, the cell numbers were determined during the cultivation period. For bone differentiation, the confluent cultures from either group were provided with osteogenic medium and incubated for 21 days during which the alkaline phosphates (ALP) activity, culture mineralization and the expression of some bone-related genes were quantified and statistically compared. MTT assay indicated thatMatrigel-cultivated cells underwent statistically less proliferation than polystyrene-cultivated cells (P<0.05). Regarding the osteogenic differentiation, ALP activity was significantly high in Matrigel versus plastic cultures. Calcium deposition in Matrigel cultures tended to be significantly extensive compared with that of control cultures (2.533±0.017 versus 0.607±0.09 mM). Furthermore, according to the semi-quantitative RT-PCR analysis, compared with polystyrene plastic surface, Matrigel seemed to provide a microenvironment in which human MSC expressed osteocalcin and collagen I genes in a significantly higher level. Collectively it seems that Matrigel could be considered as an appropriate matrix for MSC osteogenic differentiation.

Four novel losartan analogues 5a-d were synthesized by connecting a dihydropyridine nucleus to imidazole ring. The effects of 5a and 5b on angiotensin receptors (AT1) and L-type calcium channels were investigated on isolated rat aorta. Aortic rings were pre-contracted with 1 µM Angiotensin II or 80 mM KCl and relaxant effects of losartan, nifedipine, 5a and 5b were evaluated by cumulative addition of these drugs to the bath solution. The results showed that compounds 5a and 5b have both L-type calcium channel and AT1 receptor blocking activity. Their effects on AT1 receptors are 1000 and 100,000 times more than losartan respectively. The activity of compound 5b on L-type calcium channel is significantly less than nifedipine but compound 5a has comparable effect with nifedipine. Finally we concluded that these two new Compounds can be potential candidates to be used as effective antihypertensive agents.

Psychotropic medications produce their effects, in part, through increasing neurotrophin levels in the brain. Since studies concerning nerve growth factor (NGF) analysis have been limited in scope, in the current experiments we investigated the effects of diverse psychotropic agents on NGF protein levels in various brain regions of rat. Male Wistar rats receivedacute and chronic administration of drugs and electroconvulsive shock (ECS). Twenty four hr after the last treatment, NGF quantification was performed using sandwich ELISA kit. Acute administration of desipramine, phenelzine, fluoxetin, chlordiazepoxide (10 mg/kg, each), haloperidol (1 mg/kg), or clozapine (20 mg/kg) failed to alter NGF protein in any brain structure investigated. However, a single ECS treatment significantly elevated NGF protein in the hippocampus. Chronic administration (21 days) of desipramine, fluoxetine, phenelzine, haloperidol and clozapine led to a reliable enhancement of NGF protein in the frontal cortex. In addition desipramine, fluoxetine, phenelzine, and clozapine significantly increased NGF protein in the hippocampus. In the olfactory bulb, chronic injections of desipramine and fluoxetine elevated NGF level, however, phenelzine and haloperidol decreased NGF. Repeated applications of ECS (10 days) led to a remarkable augmentation of NGF protein in the frontal cortex, hippocampus, amygdala, and olfactory bulb. Neither acute nor chronic treatment with the benzodiazepine chlordiazepoxide altered NGF level in the examined brain regions. These findings suggest that diverse psychotropic treatments may regulate NGF protein level in a brain region-specific fashion which may be indicative of their therapeutic properties.

Rapidly growing mycobacteria (RGM) are capable of producing diseases in humans. Since mycobacteria vary in their susceptibility, precise identification is critical for adoption of correct drug therapy. The main aim of this study was molecular identification and evaluation of antimicrobial susceptibility pattern of Iranian clinically isolated Myocbacterium fortuitum. A total of 72 presumptively identified isolates of clinical atypical mycobacteria collected by Isfahan Research Center for Infectious Diseases & Tropical Medicine during 2006-2008 were included in the current study. A combination of conventional and molecular tests was applied to identify the isolates. Molecular methods including genus and group specific PCR and PCR-Restriction Algorithm (PRA) based on hsp65 gene were applied to achieve exact identification of mycobacterial strains. Antimicrobial susceptibility testing on M. fortuitum isolates was performed by in-house prepared broth microdilution test.. Out of 72 collected atypical mycobacteria isolates, we identified 25 strains of M. fortuitum. All strains had the specific molecular markers of mycobacterial identity and similar species specific PRA pattern of the international type strain of M. fortuitum. Drug susceptibility testing showed that the M. fortuitum isolates are sensitive to amikacin, sulfamethoxazole and ciprofloxacin (100%), imipenem (92%), clarithromycin (76%), cefoxitin (56%) and doxycycline (16%). Molecular identification of atypical mycobacteria based on PRA is a reliable and rapid approach which can identify mycobacterial strains to the species level. Our study showed that M. fortuitum plays a significant role in pulmonary and extrapulmonary infection in patients and should be given proper considerations when clinical samples are processed.

This study aimed to examine whether acetyl-L-carnitine (ALC) was able to reduce cardiac arrhythmias and infarct size in the ischemic-reperfused isolated rat heart. The isolated hearts were mounted on a Langendorff apparatus then perfused by a modified Krebs-Henseleit solution during 30 min regional ischemia and 120 min reperfusion (control) or by enriched Krebs solution with 0.375, 0.75, 1.5 and 3 mM of ALC (treatment groups). The ECGs were recorded and analyzed to determine cardiac arrhythmias. The infarct size was determined by using a computerized planimetry package. During ischemia, all used concentrations of ALC decreased number and duration of ventricular tachycardia (VT), total number of ventricular ectopic beats (VEBs) (P<0.01), incidence of total ventricular fibrillation (VF) and the time spent for reversible VF (P<0.05). At the reperfusion phase, duration of VT, incidence of total VF and reversible VF were significantly lowered by ALC (P<0.05). In addition, infarct size significantly was decreased in all treated groups. In the control group, the infarct size was 23±3.1%, however, ALC (0.375, 0.75 and 3 mM) reduced it to 8.7±2.3, 5.3±1.4, and 8±2.9%, respectively (P<0.01). Considering the results, it may be concluded that ALC has protective effects against cardiac ischemia-reperfusion (I/R) injuries by reduction of infarct size and arrhythmias in isolated rat heart. Among the potential cardioprotective mechanisms for ALC, increase in glucose oxidation and resulting reduced lactate production, reduction of toxic fatty acid metabolites and removing free radicals from the myocytes are more relevant.

This study aimed to investigate and to compare the effects of nifedipine and amlodipine, dihydropyridine (DHP) calcium channel blockers (CCBs) on perfusion pressure of isolated perfused rat kidney. Following the establishment of renal perfusion with a constant baseline pressure of 85-95 mmHg, the renal vasculature was constricted by phenylephrine (PE) injection. Changes in the baseline perfusion pressure were recorded. Then nifedipine and amlodipine prepared in perfusion medium was fed to the kidney for 30 min. Finally alterations in the baseline pressure arising from PE administrations in the presence of CCBs were recorded and data analyses were done. PE-induced increases in perfusion pressure attenuated significantly in the presence of 5 and 10 μM of nifedipine and 1, 5, and 10 μM of amlodipine. Increases in perfusion pressure arising from PE (100 and 200 μM) in the presence of amlodipine (1, 5, and 10 μM) was significantly less than that in the presence of nifedipine (1, 5, and 10 μM). Calculated EC50 value of amlodipine for inhibition was significantly lower than that of nifedipine. Based on the EC50 values, the potency of amlodipine in inhibiting PE-induced responses is significantly higher compared to nifedipine. The potency of amlodipine in inhibiting PE-induced increments in renal perfusion pressure is significantly higher compared to nifedipine.

Resistance to the new generation of cephalosporins which is mediated by Extended-Spectrum beta-lactamases (ESBLs) has been found amongEscherichia coli isolates throughout the world. These resistance genes and their producers, the micro-organisms carrying beta-lactamases, are responsible for serious clinical and therapeutic problems among inpatients and it is necessary to pay more attention to detection of ESBLs producing organisms.Materiasl and Collectively 260 isolates of E. coli were obtained from 6 hospitals in Tehran (Iran) during April-2006 to April-2007. The antibiotic susceptibility patterns of isolates were determined by disk diffusion method. phenotypic confirmatory test (PCT) was carried out for screening of ESBLs. Microbroth dilution assay was used to determine the minimum inhibitory concentration (MIC) of ceftazidime. Isolates showing MIC≥2 μg/ml were subjected to polymerase chain reaction (PCR) targeting blaTEM, blaSHV, blaCTX and blaPER genes. The PCT showed that 48.08% of isolates are ESBL producers (125 of 260). The majority of cefotaxime resistant (90.8%) and ceftazidime resistant (92.5%) isolates were ESBL producers. The obtained results by PCR revealed that 5.77% (n=15 of 260) and 24.23 (n=63) of isolates can produce SHV and TEM type enzymes respectively. blaCTX was detected in 20.38% of isolates (n=53) and none of them could produce blaPER type beta-lactamases. The results of our study showed that the ESBL genes have high prevalence among clinical isolates of E. coli. Such high dissemination of ESBLs is a serious problem for public health and therefore, it''s necessary to seek a program for monitoring ESBLs in hospitals.

Objective(s: The central nucleus of the amygdala (CeA) is a forebrain structure which is important in regulation of ingestive behavior and there is direct and circumstantial evidence to indicate that some circuits involved with feeding behavior include glutamatergic elements. The present study examined whether administration of NMA (N-Methyl-DL-aspartic acid) or MK801 into the CeA altered water intake under deprivation. Animals were deprived for 24 hr before tested for water intake. NMDA (N-methyl-D-aspartate) glutamatergic receptor agonist, NMA and its antagonist, MK801 were infused bilaterally, and water intake measured for 1 hr thereafter. The intra-CeA injection of NMDA glutamatergic agonist, NMA (0.25, 0.5 and 0.75 µg/rat) increased water intake (P<0.05). However, administration of NMDA glutamatergic antagonist, MK801 (0.25, 0.5 and 1 µg/rat) decreased water intake significantly (P<0.05). These data suggest that NMDA receptors in the CeA are responsible for the glutamatergic modulation of water intake in this nucleus.

Wound licking has been shown to advance wound healing among humans and many other animals. The present study evaluates the licking effects on healing of skin wound in rats. Twenty four rats were assigned to 4 different groups randomly and two 3 cm longitudinal full thickness incisions were made on each dorsal and ventral side of rats. The ventral incisions were considered as treated wounds because of contact to saliva as rats lick them easily and dorsal incisions as control wounds. Clinical changes and histopathological effects of rat saliva on wound healing were evaluated every day and on 3, 7, 14 and 21 days post-operation respectively. Histologic and clinical evaluation of treated wounds showed better healing than control wounds. This study showed that licking behavior can promote wound healing. Thus salivary compounds could be isolated, be mass produced and may have potential to become as common as antibiotic cream.