Iranian Journal of Basic Medical Sciences
Year:2004 | Volume:7 | Issue:2 (22)|Papers Count:12

Paragigantocellularis lateralis nucleus (LPGi) involves several functions such as cardiovascular regulation, sexual behavior, withdrawal syndrome and. pain. In addition, the role of α2 adrenergic in analgesia has been reported as well. We studied the role of α2 adrenergic receptor in LPGi on acute pain. After surgical process LPGi was lesioned bilaterally by using electrical DC current (1mA, 6 second), at stereotaxic coordinates of (AP=11.8, Lat±1.86 and Depth=10.5). Pain perception was tested using a standard hot plate. No significant difference was found between the control group and the sham group. There is a significant difference between the sham group and lesion+saline group (P<0.0002). There are significant differences between the lesion+saline group and lesion+0.02 mg/km clonidine (P<0.001) as well as lesion+saline group and lesion+0.2mg/km clonidine (P<0.001). We conclude that α2 adrenergic receptors of LPGi nucleus not only have a major role in the clonidineinduced analgesia but also may be affecting other parts of CNS to induce analgesia in rat.  

Background Interleukin-4 (IL-4) is a key anti-inflammatory cytokine and plays an important role in the cytokine network and in the Th1/Th2 balance. It is generated by helper T cells, and possibly in the early adaptive immune response by mast cells and basophiles, and like all cytokine generally expressed at low levels with a short half-life of the mRNA. There are controversial evidences suggesting the role of IL-4 and IL-13 in the pathogenesis of allergy and asthma. The purpose of this research was to indicate the role of IL-4 gene expression in allergic and non-allergic rat models. We tested three different rat strains, "allergic" high 19B producing BN (Brown Norway) strain rats, "non-allergic" low IgE responder PVG strain rats and low IgE producing WISTAR strain rats, for IL-4 mRNA and IL-4 protein expression by a semi-quantitative RT-PCR and ELISA methods. The results showed that BN generated the highest amount of IL-4 and mRNA expression level. WISTAR strain and PVG strain showed lower amount of IL-4 expression in all experiments and can be looked at the lowest IL-4 mRNA producer. Our results demonstrated the hypothesis that higher expression of IL-4 mRNA may be "allergic" and high IgE producing. Although we can not exclude the polymorphism of the IL-4 gene in the non-coding region and the role of other cytokine like IL-13 and TGF-B in the cytokine network.

Differentiation between exudates and transudates is the first diagnostic approach of a patient with pleural effusion. The aim of this study was to evaluate usefulness of pleural fluid to serum total bilirubin ratio for distinguishing exudates from transudates and to compare accuracy of this parameter with three other criteria: pleural protein, lactic dehydrogenase (LDH), cholestrol and in relation to established etiology for differentiating exudates from transudates. We prospectively studied 50 patients with pleural effusion, 34 had exudates and 16 had transudates. Correlation of pleural fluid to serum bilirubin concentration ratio of 0.6 or more with the presence of exudates as determined by other established criteria was statistically significant. Its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and efficiency were 76%, 87.5%, 93%, 63% and 87%, respectively. Therefore pleural fluid to serum bilirubin ratio can be effective for separation of exudates from transudates. In addition the bilirubin ratio is more cost effective in terms of laboratory processing and is more readily available.

The quantification of anti-red blood cell antibodies routinely performed by standard direct antiglobulin test (DAT), but there are some limits to its sensitivity and the end-point evaluation is very subjective in this method. Recently, a modified enzyme-linked immunosorbant assay (ELISA) has been applied to detect anti-red blood cell antibodies. In this method, the end-point is determined by enzyme activity of an enzyme conjugated anti-human antibodies. The enzyme converts a soluble substrate to a soluble colored product, which is proportional to amount of primary antibodies. This technique has been called enzymelinked antiglobulin test (ELAT). In this study, we tried to evaluate the analytical parameters of this technique and compare with conventional DAT method. Our results showed some modification of the previously described ELAT technique makes it feasible and simpler for the routine applications. This modified method was reproducible with the mean coefficient variation of 9.08 and 5.21 for between days. And within day assays and found to be at least sixteen times more sensitive than DAT method. Anti-D measurement showed an acceptable correlation (R 0.88) between ELAT and DAT methods. Therefore, this method could be useful for more precise monitoring of allo-immunized mothers and patients with auto immune hemolytic anti-D anemia and provide an alternative method for assessing anti-D activity of specific total IgG and IgG subclasses preparation.

We have investigated the acute effect of lovastatin on diabetes-induced endothelial dysfunction in the isolated mesenteric bed of streptozotocin-diabetic (STZ) rats. The endothelial function was tested in constantly perfused preparations isolated from rats, 12 weeks after treatment with STZ (45 mg kg, i.p.).All preparations were precontracted by Phenylephrine 10-4 M .Acetylcholine (ACh) induce relaxation in perfused mesenteric bed dose dependently. Response to Ach was reduced in diabetic group significantly. Co-perfusion with lovastatin (10-5 M, for 15 min) significantly improved the Ach-mediated relaxation removed from diabetic but not control rats. However, this beneficial effects of lovastatin was inhibited by pre-incubation of tissue with L-NAME (5 × 10-7 M, for 20 min), but not indomethacin (10-5M). The vasodilatory responses to sodium nitroprusside from control or diabetic rats were unchanged by lovastatin pretreatment. From the present results it may conclude that lovastatin significantly improves endothelial-dependent relaxation in diabetic group. It could be via increasing nitric oxide bioavalibity, most probably due to its antioxidant effe

Thymoquinone is the major active constituent of the volatile oil of Nigella sativa seeds. It has been previously reported that thymoquinone prevents oxidative injury in various hepatotoxicity models and may prevent membrane lipid peroxidation. In order to clarify the effect of thymoquinone on lipid peroxidation in CNS, we induced cerebral ischemic/reperfusion injury in rats using four-vessel occlusion (4-VO) method and consequently determined malondialdehyde (MDA) levels in hippocampus based on its reaction with thiobarbituric acid (TBA). Thymoquinone (2.5-10 mg/kg), phenytoin (50 mg/kg) and control (l0 ml/kg) were administered immediately after reperfusion. The MDA level was higher in control group (normal saline) following ischemic-reperfusion than thymoquinone treated groups. The MDA levels recovered significantly upon phenytoin and thymoquinone (5, 10 mg/kg) therapy following ischemic/reperfusion. These results suggest that thymoquinone may exhibit neuroprotective effect through an inhibitory activity against lipid peroxidation during cerebral ischemia in rats.

In order to evaluate effect of garlic on total cholesterol level in patients with hypercholesterolemia. Results of similar clinical trials are composed to gain more precise result and conclusion. This procedure is called meta-analysis. There are several statistical procedures to compose similar studies which in all of them the primary data is not required. The procedure employed in this study is meta-analysis with homogeneity of variances of treatment effects. Six homogenous studies were found among twelve published studies. After synthesis of results, effect of garlic on reduction level of cholesterol is estimated 18.0 (mg/dl) with a confidence interval (10.03, 25.0) which shows significant difference between treatment group (garlic consumption) and control group (placebo). The confidence interval computed for decline in total cholesterol level after garlic consumption is narrower than the other CIs computed in individual studies. simulation was performed to produce artificial data for comparing two method of meta-analysis applied in this research ,new proposed method was better than the common procedure especially when sample sizes of individual studies is small.

Poor absorption of protein antigens across mucosal membranes necessitates the use of drug delivery systems. Pre-formed dextran micro spheres (Sephadex®) possess a good potential for delivery of protein and peptide drugs to mucosal membranes. However they have rarely been used for mucosal immunization. Regards the advantages of mucosal over parenteral immunization and also the penetration enhancement potential of dextran microspheres, we examined their efficacy as mucosal antigen delivery system. Dextran microspheres loaded with tetanus toxoid (TT) were prepared by suspending microspheres in TT solution followed by freeze-drying. Size and morphological features of microspheres were studied by optical and electron microscopes. Encapsulation efficiency of TT was determined by micro-BCA protein assay. In vitro release study was performed in a model, simulating nasal cavity. Immunoreactivity of encapsulated antigen was assayed by ELISA. Gamma-scintigraphy (GS) was used for determination of mucoadhesion and clearance rate of micro spheres, by spraying of technetiumlabelled micro spheres to the nose of human volunteers. Local irritating potential of microspheres was studied by nasal administration to human nose. Microspheres with a mean diameter of about 150 µm and a TT encapsulation efficiency of 20.3% (n=3) were obtained. Antigenicity of encapsulated TT was determined as 90.5±1.8% (n=3) that of the original TT. Release studies showed that almost 100% of TT was released in 1 h. GS studies showed that after 4 h, 36.9±3.4% (n=4) of microspheres were cleared from nasopharynx region of volunteers. Considering the suitable release characteristics, desirable preservation of the antigenic activity of TT, appropriate mucoadhesive properties and also safety of TT loaded Sephadex microspheres, these microspheres could be used as a proper mucosal antigen delivery system. However further studies are needed regarding the immune response induced by these systems in an animal model.