Iranian Biomedical Journal
Year:2005 | Volume:9 | Issue:2|Papers Count:8

The incidence of virulence factors among 114 Enterococcus faecalis and 35 Enterococcus faecium strains from different clinical specimens were compared with those isolated from control groups. A few of the isolates expressed two or more of the following traits simultaneously: hemolysin, aggregation substance, gelatinase, DNase, hemagglutinin and antibiotic resistance. The frequencies of hemolysin, aggregation substance, and gelatinase production in E. faecalis were much higher than those in E. faecium. However, no statistically significant differences were detected in the other traits. Two of the isolates showed total resistance to all of the antibiotics tested, and others displayed varied degrees of resistance pattern. The frequency of plasmid transfer was shown to be 10-4- 10-7 per donor among the isolated strains. The plasmid profile of the bacteria indicated that most of the isolates contained one or more plasmids with molecular weight ranging in 2 to 42 Mda regions. Resistance to gentamicin and tetracycline was the most observed antibiotic resistance pattern, and had the property of efficient inter-enterococcal spp. transfer by mating.

Artemisia species, growing in almost all the northern hemisphere, is used in folk medicine of some countries as a remedy for hypertension. Since some cardiovascular disorders including hypertension are accompanied with altered responsiveness of vascular alpha-adrenergic receptors, the effect of aqueous Artemisia annua extract (100 and 200 mg kg-1) on -adrenoceptor agonist-induced contraction of rat aorta was investigsted. After 4 weeks, the contraction and endothelium-dependent and -independent relaxation response of extract-treated rats were recorded. The results showed that the contractile response of aortic rings with endothelium to phenylephrine in extract-treated rats decreases (P<0.01-0.0001) and their endothelium-dependent relaxation response to acetylcholine increases (P<0.01-0.001) significantly in comparison with controls. Endothelium-denuded aortic rings from extract-treated rats also showed a significant decrease (P<0.05) in contractile response, but there was no considerable difference in their endothelium-independent relaxation response to isosorbide dinitrate. These data suggest that the aqueous extract of Artemisia annua could attenuate contractile response and enhance the endothelium-dependent relaxation response of aortic rings from normal rats.

The variations of glucose 6-phosphate dehydrogenase (G6PD) activity in different brain regions of normal, hypo- and hyperthyroid rats were investigated. Hypo- and hyperthyrodism were experimentaly induced by administration of methimazol and liothyronine, respectively. In normal rats, midbrain had the minimum (70 mU/mg) and cerebral cortex the maximum (349 mU/mg) G6PD activity. Hyperthyrodism increased the enzime activities in straitum (72%) and midbrain (144 %). Hypothyrodism also elevated G6PD activities in the two above regioins but to a lesser extent. The enzyme activities were decreased by hypothyrodism in hypothalamus (73%) and cerebellum (45%). Hyperthyrodism, however, increased G6PD activities in cerebellum by (16%) but did not significantly change the enzyme activity in hypothalamus. Neither hypo- nor hyperthyrodism affected cerebral cortex G6PD activity. The data suggest that the changes in G6PD activities of the brain regions may have been occured via different thyroid hormone effect on the regions.

Herpes simplex virus type-1 (HSV-1) causes a variety of diseases in human. This virus is a neurotropic pathogen of human that establishes latent infection in the sensory ganglia innervating the site of primary infection. A number of genes including ICP34.5 control HSV-1 pathogenicity and ICP34.5 has been identified as HSV-1 virulence gene. Open reading frame P (ORF P) is also a HSV-1 gene that might have a role in latency. A complication in the analysis of the role of ICP34.5 and ORF P in the HSV-1 life cycle is that these two are overlapping antisense genes. ORF P is also deleted in ICP34.5 negative mutants and to date, no definite function is attributed to it. To attribute characteristics which were originally attributed solely to ICP34.5 to each of these two genes (ORF P or ICP34.5), an approach is to construct a number of HSV-1 recombinant viruses that express ICP34.5 and ORF P independently. An alternative way is to determine if ORF P interacts with any of the cellular and viral proteins both in vitro and in vivo. Using Glutathione-S-transferase (GST) pulldown assay and Western-blotting, we showed that ORF P interacts with a cellular splicing factor (SC35) in vitro. To investigate the colocalization of ORF P and SC35, nuclear and cytoplasmic fractionation of ORF P/SC35 was also carried out. Our results showed that both SC35 and ORF P are located in the nucleus of HSV-1 infected cells. Conclusively, because ORF P interacts and colocalizes with SC35, it might have a role in splicing.

The aim of this study was to evaluate changes that occur in motility parameters of progesterone treated mouse spermatozoa during course of hyperactivation. Mouse spermatozoa treated with different doses of progesterone were videotaped after 10 min and 90 min of incubation. For each sperm, one second of movement of the head-midpiece junction was traced from the videotape and for each tracing; seven motility parameters were studied using computer assisted image analysis. For all progesterone treated spermatozoa, motility rate differed significantly from control group after 90 min of incubation. Motility parameters for high doses of progesterone 10 and 100 µg/ml showed hyperactivation occurred during 10 min of incubation. With treatment of 1 µg/ml progesterone, hyperactivated motility pattern of spermatozoa occurred 90 min after incubation similar to the control group showing that low dose of progesterone is unable to induce hyperactivation. In conclusion, progesterone induces hyperactivation in mouse sperm and reduces the motility rate during the time.

In an effort to evaluate the hypoglycemic activity of T. polium, the crude extract was administered orally to a group of Streptozotocin induced diabetic rats for 6 consecutive weeks. Significant decrease in blood glucose by 64%, total bilirubin by 35%, glutamate oxaloacetate transferase by 48% and glutamate pyruvate transferase by 30% was observed compared to untreated diabetic rats. However, the blood insulin level was enhanced by almost 160%. The insulinotropic property of the T. polium crude extract was further assessed by an in vitro investigation using isolated rat islets. Our data indicated that T. polium crude extract is capable of enhancing insulin secretion by almost 135% after one dose of treatment at high glucose concentration. Meanwhile, without affecting the time pattern of insulin secretion by the islets, the plant extract seems to be capable of regenerating the islets of langerhans in the treated compared to the untreated diabetic rats. These data clearly provide a mechanistic view concerning the hypoglycemic effect of T. polium extract through its significant effect on the pancreas.

cyclodextrin glucosyl transferase (CGTase) hydrolyses starch to produce â-cyclodextrin by transglycosylation (cyclization) activity. The conventional method for detection of CGTase activity is based on detecting starch hydrolysis by iodine staining. This method reveals all amylolytic enzymes, but can not discriminate them. In the present study, we introduce a new method for specific detection of CGTase activity and its specific product i.e. cyclodextrin by polyacrylamide gel. In this method, solution containing CGTase is subjected to electrophoresis on 10% polyacrylamide gel. Then, the gel is covered with an indicator gel containing phenolphthalein, soluble starch, and agar. After a short incubation, sodium carbonate solution is added and the positive result is indicated by the emergence of a colorless band in the red context of the indicator gel. Since the production of cyclodextrin via cyclization is unique to CGTase, the emergence of clear bands is indicative of CGTase presence. However, in conventional starch-iodine method, all amylolytic enzymes including CGTase give positive results. Therefore, for detection of CGTase, the phenolphthalein indicator gel method, compared to the starch-iodine method, is more specific.

Hydatidosis, caused by the larval stage of Echinococcus granulosus, is one of the most important zoonosis with worldwide distribution. As its diagnosis by clinical symptoms and scanning alone is difficult and confusing, we designed the present study to achieve a sensitive and simple diagnostic method for epidemiological studies. Sera (250 samples) were collected from 90 cases of hydatidosis proven by surgical operation, 80 patients with diseases other than hydatidosis and 80 healthy cases. The antigen (Ag) used was a crude hydatid fluid Ag obtained from lung and liver cycts of sheep slaughtered in Tehran abattoir (Iran). The result of dot-ELISA showed 100% sensitivity and 98.75% specificity . Positive and negative predictive values were 97.82% and 100% respectively. In the case of sandwich ELISA, the results were as follows: 92.22% sensitivity, 98.75% specificity, positive and negative predictive values: 97.64% and 95.75 %, respectively. In both techniques, cross reaction with fasciolosis was observed for two cases. In conclusion, although these two tests had very similar results, dot-ELISA was more acceptable with respect to its higher sensitivity and simplicity in practice.