Iranian Journal of Basic Medical Sciences
Volume:11 Issue: 4, Winter 2009

Nitric oxide is a short-lived mediator, which can be induced in a variety of cell types and produces many physiologic and metabolic changes in target cells. It is important in many biological functions and generated from L-arginine by the enzyme nitric oxide synthase. Nitric oxide conveys a variety of messages between cells, including signals for vasorelaxation, neurotransmission and cytotoxicity. In macrophages, nitric oxide synthase activity appears slowly after exposure of the cells to cytokines and bacterial products, is sustained, and functions independently of calcium and calmodulin. The cytokine- inducible nitric oxide synthase (iNOS) is activated by several immunological stimuli, leading to the production of large quantities of nitric oxide which can be cytotoxic. To date, there have been conflicting reports concerning the clinical significance of nitric oxide in infections. Some authors have proposed that nitric oxide contributes to the development of severe and complicated cases, while others have argued that nitric oxide has a protective role. The aim of this review is to evaluate the functions of nitric oxide production toward oxidative stress induced by infections or inflammations. It is indicated that NO is an important, but possibly not essential contributor in the control of acute phase of infections and it is only part of an immunopathological chain against pathogens. The anti-microbial function does not relate only to nitric oxide action or its related molecules, a combination of nitric oxide and immune factors is required to resolve pathogenic micro-organisms. Consequently, the NO theory in infectious diseases may lead to the novel ideas for therapy and prevention.

While the nucleus accumbens and the striatum have received much attention regarding their roles in stereotyped behaviors, the role of the medial prefrontal cortex (mPFC) has not been investigated to the same degree. Few studies have reported the role of the mPFC in dopaminergic induction of locomotor hyperactivity. The mPFC is a heterogeneous area (the anterior cingulated, prelimbic, and the infralimbic)with particular inputs and outputs to subcortical regions that may have different effects on stereotyped behaviors. In this work, apomorphine, a non-specific dopamine agonist, was microinjected into the three different subregions of the mPFC for induction of stereotyped behaviors to show the role of the three subareas of the mPFC on behaviors and its heterogeneity. Cannulas implanted in the infralimbic, the prelimbic orthe anterior cingulated areas of the mPFC. Apomorphine microinjected at five doses and then behaviors recorded. There were significant differences among three areas. The rats receiving apomorphine in the anterior cingulated showed less sniffing and climbing but more chewing behaviors. Yawning observed more significantly in the rats given apomorphine in the prelimbic area. The rats getting apomorphine in the infralimbic of the mPFC showed more climbing behavior. It was indicated that manipulation of the dopaminergic system in mPFC alters behaviors and with regard to this, there may be heterogeneity among its three subregions.

Herpes simplex viruses (HSVs) have widespread and ubiquitous prevalence in the human population and they have received a great deal of attention due to the range of diseases, they caused as a result of an infection. It seems that the fast and reliable diagnostic methods are needed for detecting the herpes simplex virus type 1 (HSV1) antibodies especially in patients with HSV encephalitis, immunocompromised people, and neonatal infections. The aim of this study was designing a Western blotting method for HSV1 antibody detection, using the purified virus by sucrose density gradient centrifugation procedure. The most reliable method for HSV detection is virus neutralization test but it needs cell culture preparation, high expertise, as well as the high amounts of serum samples. Considering the difficulties of this method, we tried to run a new one for HSV antibody detection by propagating the viruses and then purify them by sucrose density gradient centrifugation method. The purified viruses used as antigens in Western blotting assay.Diluted sera (1:100, and 1:200 dilutions) used in Western blotting and two-fold dilutions of the sera applied in virus neutralization test. Five of twenty seven samples were negative in Western blotting and the same results obtained in virus neutralization test. Comparing with our gold standard, the sensitivity and specificity of the developed assay were both 100%.Our results show that the designed method is a reliable method for replacing the virus neutralization test in diagnostic laboratories. It can also, be used for confirming the ELISA results.

Nicotinic acetylcholine receptors (nAChRs) regulate epileptiform activity and produce a sustained pro-epileptogenic action within the hippocampal slices. In the present study, we investigated the effect of nAChRs on evoked glutamatergic synaptic transmission in area CA3 and CA1 of rat hippocampal slices to identify possible excitatory circuits through which activation of nAChRs produce their pro-epileptogenic effects. Hippocampal slices (400 µm thick) prepared in vitro from male Wistar rats (3-5 weeks), using standard procedures. Following 1 hr equilibration in artificial cerebrospinal fluid (ACSF), slices transferred to an interface recording chamber. Stimulatory electrodes placed within the hilus or Schaffer-collateral pathways and extracellular field recordings made in the stratum radiatum of the CA1 and CA3 regions to investigate evoked synaptic responses. Bath application of the selective nAChR agonist dimethylphenyl-piperanzinium (DMPP, 30 mM) resulted in a sustained and reversible enhancement of glutamate afferent evoked fEPSP amplitude by 15.7±5.1% (mean±SEM; n=8 of 12) in the CA3 region of the hippocampus but not in the CA1 (-5.25±8.3%, mean±SEM; n=5). Activation of nAChRs may produce pro-epileptogenic actions in part through regulating glutamatergic circuits. Difference in nAChR regulation is also evident between different regions of hippocampus.

Dracocephalum moldavica (D. moldavica) have been traditionally used as a cardiotonic agent in the folk medicine of some regions of Iran. In the present study, effects of total extract of D. moldavica on ischemia/reperfusion induced arrhythmias and infarct size investigated in isolated rat heart.The isolated hearts were mounted on a Langendorff apparatus then perfused during 30 min regional ischemia and 120 min reperfusion, either by a modified Krebs-Henseleit solution as the control group or by enriched Krebs solution with total extract of D. moldavica (25-200 µg/ml) as the treatment groups. The ECGs recorded and analyzed to determine cardiac arrhythmias. At the end of the reperfusion, the hearts stained by Evans blue solution then incubated by triphenyltetrazolium chloride. The volume of infarcted tissue and percentage of infarct size determined by computerized planimetry. The results demonstrated that total extract of D. moldavica caused a significant reduction in the number of ventricular tachycardia (VT), total ventricular ectopic beats (VEBs) and VT duration in ischemic and reperfusion periods. The incidence of ischemic VT reduced from 93% in the control group to 0, 50 and 50% in the treatment groups. The infarct size was 37±1% in the control group, however, perfusion of the extract (25, 50, 200 µg/ml) reduced it to 13±2, 8±1 and 18±2%, respectively (P<0.001). In addition, the extract remarkably lowered volume of infarcted tissue compared to the control group (P<0.05). Our findings showed cardioprotective effects of total extract of D. moldavica against ischemia/reperfusion injuries in the isolated rat heart.

The aim of this study was to evaluate antioxidant and hair growth activities of Buxus wallichiana Baill (Buxaceae). Petroleum ether, chloroform, methanol and aqueous extracts ofBuxus wallichiana subjected to antioxidant activity by; 2, 2-diphenyl-1-picryl hydrazyl and nitric oxide methods. Methanol extract of Buxus wallichiana at 50, 100 mg/kg, ointment of methanol extract at 5 and 10% used for the evaluation of hair growth property. Methanol extract showed potential antioxidant activity. Methanol extract at 100 mg/kg showed consistent and significant increase in mean score of hair growth from day 3 to day 24. Whereas 50 mg/kg increased the mean score significantly, only from day 15 to day 24. When methanol extract at 10% applied topically, significant increase in mean hair score observed only from day 15, but at 5% showed considerable increase in mean hair score only from day 21 and 24, when compared to the control. The result of this study suggests that Methanol extract of Buxus wallichiana possess good antioxidant and hair growth activity.

Using a cancer murine model of invasive aspergillosis (IA), we investigated the expression of TLR-2, Dectin-1 and the level of cytokine production by CD4+ T helper cells in different groups of mice (with or without cancer), also, the effect of invasive aspergillosis on the immune response pattern of cancer mice. Patterns of susceptibility and resistance to infection obtained with different groups of mice injected with Aspergillus fumigatusconidia. TLR-2 and Dectin-1 analyzed applying flowcytometry and cytokine production of cultured splenocytes by ELISA method.Cancer mice that challenged with A. fumigatus conidia showed significant increase in TLR-2 and Dectin-1 levels compared with the two other control groups (normal mice challenged with A. fumigatus and non-infected cancer mice). Moreover, it showed insignificant decrease in IFN-γ and IL-10 levels and insignificant increase in TNF-α level. The data demonstrated remarkable rise in IL-4 level and the mortality of cancer mice that intravenously infected with A. fumigatus. Probably IA causes stimulation in innate immunity and Th2 cells, also some disorganization in cytokine production in CD4+ T helper cells. We hypothesize that concomitance of IA and cancer may change the microenvironment for local or systemic immune responses. Other complementary studies could help supporting our hypothesis.

The cytotoxic effects of crude ethanol extracts of some previously tested Iranian conifers on tumor cell lines have motivated us to screen different parts of two subspecies in these genus. Terminal branchlets and berries of Juniperus excelsa subsp. excelsa and J. excelsa subsp. polycarpos were collected, dried and extracted with ethanol/H2O (80/20 v/v) via percolation procedure. Extracts were dried, reconstituted in ethanol and cytotoxic effects of different concentrations were determined on cancer cells by ELISA, using MTT assay. MDA-MB-468, Hela and KB cells were used in this study.The extracts of the branchlets of male and female of J. excelsa subsp.polycarpos as well as berries extract of J. excelsa subsp. excelsa showed inhibitory activities against KB cells. Extracts of female branchlets and berries of J. excelsa subsp. polycarpos were cytotoxic against all 3 cell lines. In conclusion, obtained extracts from J. excelsa subsp. polycarpos showed cytotoxic effects against most tested cell lines which was comparable to doxorubicin; whereas, berries extracts ofJ. excelsa subsp. excelsa showed inhibitory effects only against KB cells.