NON-LINEAR ADAPTIVE PHENOMENA WHICH DECREASE THE RISK OF INFECTION AFTER PRE-EXPOSURE TO RADIOFREQUENCY RADIATION

Substantial evidence indicates that adaptive response induced by low doses of ionizing radiation can result in resistance to the damage caused by a subsequently high-dose radiation or cause cross-resistance to other non-radiation stressors. Adaptive response contradicts the linear-non-threshold (LNT) dose-response model for ionizing radiation. We have previously reported that exposure of laboratory animals to radiofrequency radiation can induce a survival adaptive response. Furthermore, we have indicated that pre-exposure of mice to radiofrequency radiation emitted by a GSM mobile phone increased their resistance to a subsequent Escherichia coli infection. In this study, the survival rates in animals receiving both adapting (radiofrequency) and challenge dose (bacteria) and the animals receiving only the challenge dose (bacteria) were 56% and 20%, respectively. In this light, our findings contribute to the assumption that radiofrequency-induced adaptive response can be used as an efficient method for decreasing the risk of infection in immunosuppressed irradiated individuals. The implication of this phenomenon in human’s long term stay in the space is also discussed

Emergence of Multidrug Resistance and Metallo‑beta‑lactamase Producing Acinetobacter baumannii Isolated from Patients in Shiraz, Iran

Background: Metallo‑beta‑lactamase (MβL) enzymes production is one of the most important resistance mechanisms against carbapenems in some bacteria including Acinetobacter baumannii. Aims: This study was aimed to determine the antimicrobial susceptibility and the prevalence of MβL among carbapenem‑resistant isolates of A. baumannii. Materials and Methods: In this cross‑sectional study from October 2012 to April 2013, 98 isolates were identified as A. baumannii using Microgen™ kits and confirmed by molecular method. These isolates were tested for antimicrobial susceptibilities by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Carbapenem‑resistant isolates were further detected phenotypically by MβL minimal inhibitory concentration (MIC)‑test strips, and subsequently positive MβL isolates were confirmed by polymerase chain reaction (PCR). Results: Overall, 98% (96/98) of A. baumannii isolates were detected as carbapenem‑resistant by MIC test. Highest sensitivity to the tested antibiotic with 42.9% (42/98) was observed to colistin. Of 96 carbapenem‑resistant isolates, 43 were phenotypically positive for MβL; out of 43 isolates, 37 were confirmed for the presence of MβL genes by PCR. Conclusion: The frequency of drug resistance among the clinical samples of A. baumannii isolated in our study against most of the antibiotics was very high. Moreover, all MβL producing isolates were multidrug resistance. Therefore, systematic surveillance to detect MβL producing bacteria and rational prescription and use of carbapenems could be helpful to prevent the spread of carbapenem resistance.Keywords: Acinetobacter baumannii, Antibiotic resistance, Carbapenem, Iran, Metallo‑beta‑lactamas

Thermodynamic Properties of the One-Dimensional Extended Quantum Compass Model in the Presence of a Transverse Field

The presence of a quantum critical point can significantly affect the thermodynamic properties of a material at finite temperatures. This is reflected, e.g., in the entropy landscape S(T; c) in the vicinity of a quantum critical point, yielding particularly strong variations for varying the tuning parameter c such as magnetic field. In this work we have studied the thermodynamic properties of the quantum compass model in the presence of a transverse field. The specific heat, entropy and cooling rate under an adiabatic demagnetization process have been calculated. During an adiabatic (de)magnetization process temperature drops in the vicinity of a field-induced zero-temperature quantum phase transitions. However close to field-induced quantum phase transitions we observe a large magnetocaloric effect

Seroepidemiology of Varicella and value of self-reported history of Varicella infection in Iranian medical students

Objectives: We conducted this study to assess the seroprevalence of Varicella zoster virus (VZV) antibodies in a group of Iranian medical sciences students that were at risk of Varicella and the value of self-reported history as a predictor of immunity. Material and Methods: 255 medical, nursing and obstetrics students who had not entered as a student or worked in a hospital from 3 different schools were enrolled in the study in 2012 (Qazvin province, Iran). Demographics and other information as well as the history of Varicella were obtained through a self-administered questionnaire. Blood samples were collected to determine the Varicella IgG levels via an enzyme-linked immunosorbent assay. A statistical analysis was performed by calculating prevalences and their 95% confidence intervals. Sensitivity, specificity, positive and negative predictive values, Cohen's kappa and positive and negative likelihood ratios of recalled history were determined. p < 0.05 was considered statistically significant. Results: The mean age of participants was 21.3±4.3 years. Seropositivity rate was 74.5%. The relationships between marital status, number of family members, and acquired VZV history with immunity against the virus were statistically significant. The overall rate of reported history was 57%. The positive and negative predictive values of self-reported history of Varicella were 91% and 47.3%, respectively. Conclusions: Immunization of students of Iranian medical sciences seems logical in the near future. Also, they should be tested for Varicella immunity regardless of the history of previous infection

Effects of sodium valproate on the replication of herpes simplex virus type 1: An in vitro study

Abstract Background: Sodium valproate, an anticonvulsant drug, is reported to stimulate Human Immunodeficiency Virus type 1 and Human cytomegalovirus replication. Since epileptic patients undergoing sodium valproate therapy may suffer from various virus infections, the effect of this drug on replication of viruses especially those affecting neuronal tissues such as Herpes simplex virus type 1 is worthy of investigation. Methods: Viral replication was studied by quantal response method. Electron microscopy was also performed on cell monolayers treated with the drug and infected with the virus. Results: Significant reduction in viral infectivity was observed in cell cultures exposed to 0.5-2 mM of sodium valproate either one hr before or after infection. The corresponding electron microscopic examination revealed a very few intracytoplasmic enveloped virions and a marked reduction in the number of intracytoplasmic nucleocapsids in drug-treated virus infected cells compared with those of infected control. However, significant stimulation of virus replication was found upon treatment of cells with 1 mM (p<0.01) and 2 mM (p<0.001) of the drug 24 hours prior to infection. No remarkable change was seen in corresponding electron micrographs. Conclusion: Although the ultimate outcome of this study awaits in vivo assessments, possible stimulation of Herpes simplex virus type 1 replication by sodium valproate should be considered by clinicians prescribing this drug

In vitro study of antibacterial property and cytotoxic effects of aqueous, ethanolic, methanolic, and hydroalcoholic extracts of fenugreek seed

Background: Fenugreek (Trigonella Foenum-graecum) seed is reported to have anti-diabetic, anti-microbial, anti-parasitic, and hypocholesterolemic effects. Aim: To evaluate the antibacterial activity and cytotoxic effect of aqueous, ethanolic, methanolic, and hydroalcoholic extracts of fenugreek seed in-vitro. Methods: Aqueous, ethanolic, methanolic, and hydroalcoholic extracts of fenugreek seed were prepared by maceration method. In this study, six standard bacterial strains were selected including; Salmonella Typhi, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Streptococcus pyogenes. The antibacterial effect of fenugreek extracts was determined, using well diffusion agar and broth micro-dilution method. Cytotoxicity was determined on Vero cells by MTT (thiazolyl blue tetrazolium dye) assay. Results: In well diffusion agar method, none of the extracts showed inhibition zone on the bacterial strains. In the broth micro-dilution method, the MIC of the hydroalcoholic extract was determined 100, 100, 50, 100, and 100mg/mL for Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhi, Streptococcus pyogenes and Staphylococcus aureus, respectively. Also, MIC of the methanolic extract on Streptococcus pyogenes was 100mg/mL. Minimum inhibitory concentration (MIC) could not be determined for other extracts. Conclusion: Our results showed that although fenugreek seed extracts might have antibacterial activity in concentration of 50-100 mg/mL, in safe and non-toxic concentrations have no in-vitro antibacterial effect on the studied bacteria. © 2018 Lahore Medical And Dental College. All rights reserved

In vitro Investigation of Hydro-alcoholic Extract of Helichrysum leucocephalum on the Inhibition of Streptococcus Mutans Growth

Statement of Problem: Indiscriminate use of antibacterial agents increases the antibiotic resistance, which consequently necessitates seeking alternatives such as herbal remedies. Objectives: The aim of this study was to evaluate the antimicrobial effect of hydroalcoholic extract of Helichrysum leucocephalum (H.leucocephalum) on Streptococcus mutans (S. mutans) growth as a major cause of dental caries. Materials and Methods: In this study, hydroalcoholic extract of H. leucocephalum was prepared. The antibacterial effects, minimal inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) of hydroalcoholic extract of H. leucocephalum and penicillin were assessed. Agar well diffusion method and micro broth dilution assay were used on bacterial suspension adjusted to a 0.5 McFarland standard (equivalent to 1.5×108 CFU/mL).Each test was repeated four times to minimize lab errors. Results: In this study, the inhibitory zone of hydroalcoholic extract of H.leucocephalum in concentration of 100 mg/mL was 34±0.1 mm and for penicillin was 10 mm. The MIC and MBC of H.leucocephalum hydroalcoholic extract were 5.6±6.25, 21.6±6.25 mg/mL, respectively. Conclusions: Hydroalcoholic extract of H. leucocephalum have antibacterial effect on S.mutans at a concentration of 12.5mg/mL, indicating possible application of this extract in prevention of dental caries; however, future researches are necessary

Synthesis of 2-methoxy-6-(pyrazin-2-ylimino methyl) phenol and its antibacterial activitity

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An In vitro Analysis of the Effects of Iron Sulfate and Iron Acetate on Streptococcus mutans

Statement of problem: Dental caries is a common infectious disease induced by Streptococcus mutans (S. mutans). Objectives: Due to the high incidence rate of dental caries and iron deficiency in the Iranian population, we have conducted this study to analyze the effects of iron acetate and iron sulfate on controlling the growth of S. mutans. Materials and Methods: In this in vitro study, we evaluated the antibacterial effects of iron sulfate and iron acetate on S. mutans by the disk diffusion method, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results were compared to those for 0.2% chlorhexidine and penicillin as the controls. Results: Iron sulfate had higher MIC and MBC values compared to penicillin and chlorhexidine (P<0.001). Iron acetate MIC and MBC values did not significantly differ with penicillin and chlorhexidine. The iron sulfate inhibition zones at the 25 and 50 µg/mL doses were more than those of iron acetate. Conclusions: Iron sulfate and iron acetate solutions can inhibit the growth of S. mutans. Hence, different compounds that contain iron salts such as toothpastes, mouth washes, and food supplements can be produced to prevent dental caries and iron deficiency