مجله دانشکده پزشکی اصفهان
پیاپی 307 (هفته چهارم آذر 1393)

Bacterial drug resistance due to overuse of antibiotics and several mechanisms of resistance by bacteria is increasing. Multi-drug resistant bacteria (MDR) in different parts of the hospital including the ICU, cause nosocomial infections and resistance to antibiotics made them difficult to treat. Alternative methods of treatment are one way to solve this problem. Bacteriophages are antibacterial agents that specifically attack their host. In this study, Pseudomonas specific lytic phages isolated from the clinical environment and its effect on MDR P. aeruginosa was investigated. In a cross sectional study in 2013, isolates of Pseudomonas aeruginosa from clinical specimens of patients admitted to the ICU were identified by biochemical methods then antibiotic resistance patterns was determined by standard disk diffusion method according to CLSI and used as indicator hosts to screen phages from water samples. 42 strains of Pseudomonas aeruginosa have been isolated from the ICU.The antibiotic resistant patterns of bacterial isolates were as follows: 88%to amikacin, 90% to cefepime, 85% to ceftazidime, 90% to gentamicin, 75%to imipenem and meropenem and 95% to ciprofloxacin. Lytic bacteriophage was isolated only from hospital wastewater. The isolated bacteriophage had no effect on non-MDR P. aeruginosa and other Gram-negative bacteria. Bacterial resistance to antibiotics is increasing. New alternative methods such as phage therapy would open new insights in treatment of multidrug resisitant bacterial infections.

The widespread use of herbal medicines because of their protective effects on various organs has been shown in many studies. Silymarin is a flavonolignan complex isolated from the milk thistle (Silybum marianum L. Gaertn), has been clinically used for its anti-inflammatory and hepatoprotective effects. Recently, immunomodulating effects of this plant have considered by the researchers. This study aimed to investigated the effect of silymarin and DMSO on the human T lymphocyte proliferation under the cell culture conditions. Peripheral blood mononuclear cells (PBMCs) from the healthy individuals were activated with Con A (10 μg/ml) and treated with silymarin at different concentrations (0.001, 0.01, 0.1, 1, 10, 100 and 200 μM). Then, cells were incubated for five days (at 37◦ C with 5% CO2) for proliferation assay using the CFSE dye and for viability analysis using flow cytometry. We analyzed the data using the Graph pad prism (version 6). This study showed that silymarin has the ability to inhibit the T cell proliferation in vitro. Moreover, 100 μM and 200 μM of silymarin (P < 0.001) had more inhibitory effect on T cells. We conclude that Silymarin exerts immunosuppression effects, and it could be used in therapeutic situations with fewer side effects compared with the other immunosuppressive drugs.

Increasing number of bacteria which their genome sequenced leads to wide spread utilization of this data. Use of genomic information is possible through the simultaneous application of bioinformatics and bacteriology. Bioinformatics study of pathogenic bacteria indicates significant variation in genome size. There are several hypotheses about the reason of this variety as well as the relationship between fundamental processes of bacteria and genome size. The aim of this study was to investigate the relationship between genetic characteristics and behavior of pathogenic bacteria and genome size. The genome sequence data of 100 species of pathogenic bacteria were collected from different sources. The association of genome size with some characteristics of pathogenic bacteria was evaluated. Data were analyzed using SPSS statistical software, version 19.0. A significant relation was observed between the genome sizes of pathogenic bacteria with regard to some genomic features including G+C % content, the total number of genes, proteins, pseudogenes, acquired genes and some behavioral and ecological characteristics of bacteria, such as mobility, host range and breathing. Gene distribution and percent of non-protein-coding DNA have no correlation with genome size. There is a high DNA flexibility in pathogenic bacteria, and the size of the DNA is decreased during the evolution. This may lead to loss of some genes and less often acquire genes. These factors cause a reduction in the number of proteins and G + C percentage of bacteria which may account for their habitat limitation.

Metformin as a biguanid drug entered to the market 50 years ago and now is generally recommended as the first-line treatment of type 2 diabetes, especially in overweight patients, however in recent years new indications for its use have found. Recently, much attention has been directed toward the possible renal protective efficiency of metformin. Recent studies have proven that metformin, possesses antioxidant efficacy as well. Reduction of apoptosis, induced by oxidative stress in endothelial cells and prevention of vascular dysfunction was found with metformin treatment.

Pulmonary arterial hypertension (PHA) is a frequent complication of congenital heart disease (CHD), most commonly in systemic-to-pulmonary shunt lesions. In patients with an uncorrected left-to right shunt, PAH will end up to Eisenmenger syndrome,that is contraindication of surgery. What about patients with Moderate to severe PAH who do not have criteria of Eisenmenger syndrome. Immediate cardiac repair is preferred or medical treatment? Heart catheterization and evaluation of pulmonary artery reactivity test or lung biopsy might be helpful to find presence of Eisenmenger syndrome. Although these guidelines are not always helpful or possible. Look at the following article will show how important this subject is. 192 patient with CHD and PAH were evaluated in 4 groups, Eisenmenger syndrome (90 patients), left- to- right shunt with PAH (48 patients), PAH with small defect (10 patients) and PAH after defect correction (44 patients). One, 5, 10, and 20 year survival was estimated for each group. Findings showed that patients with history of surgery in presence of PAH have worst outcome. And patients with Eisenmenger syndrome and those with PAH- associated with left- to- right shunt have best prognosis, one of the reasons of this result is presence of a cardiac defect which allows a pulmonary- to- systemic shunt which can maintain the cardiac output in the end- stage of disease. Finally I present a young girl with history of CHD with PAH. She had been operated several years ago. When I admitted her, she was in a bad condition, with Functional class IV. Echo study showed severe PAH. Treatment of PAH with specific target PAH drugs started immediately, but these treatment were too late and patient expired in the hospital. Finally, I would like to pose the question”Wouldn’t it be better if the patient had not undergone the surgery in the first place”.