Effect of the bacterial growth phase and coculture conditions on the interaction of Acanthamoeba castellanii with Shigella dysenteriae,Shigella flexneri,and Shigella sonnei

Shigella species and Acanthamoeba castellanii share the same ecological niches, and their interaction has been addressed in a limited number of research. However, there are still uncertain aspects and discrepant findings of this interaction. In the present study, the effects of the bacterial growth phase, cocultivation temperature and the type of culture media on the interaction of A. castellanii with Shigella dysenteriae, Shigella sonnei and Shigella flexneri were evaluated. In nutrient‐poor page's amoeba saline (PAS) medium, the number of recovered bacteria and the uptake rates were significantly higher in stationary phase cells than logarithmic phase cells. However, no significant differences were observed in the number of recovered bacteria and the uptake rates between logarithmic and stationary phase cells in nutrient‐rich peptone–yeast extract–glucose (PYG) medium. While the number of recovered bacteria was significantly higher in nutrient‐rich than nutrient‐poor media, in all the three Shigella species, the bacterial uptake rates were significantly higher in nutrient‐poor than nutrient‐rich media at both cocultivation temperatures. In both nutrient‐poor and nutrient‐rich media and at both cocultivation temperatures, the number of viable Shigella species after 24 h incubation were not influenced by the presence of A. castellanii. Although Shigella species did not proliferate in A. castellanii trophozoites, a considerable number of bacteria were survived in the trophozoites up to 15 days. From the public health perspective, the results of this study are important for further understanding of the nature of the interaction of these organisms and to deal with Shigella species in the environment.     

The role of Candida albicans in the severity of multiple sclerosis

The purpose of this study was to compare the specific activity of proteinase A in Candida albicans (C. albicans) between multiple sclerosis (MS) patients and controls. A total of 135 and 100 C. albicans strains were isolated from superficial surfaces of MS patients and healthy controls. Analytical models (regression and neural network) were applied to predict the severity of MS considering specific enzyme activity (SEA) and other factors which affect the expanded disability status scale (EDSS). The SEA of C. albicans in MS patients (3466.95 ± 277.25 μmol min^?1 mg^?1) was significantly more than that of healthy controls (1108.98 ± 294.51 μmol min^?1 mg^?1) that was confirmed by regression model (P < 0.001). The SEA had a positive correlation with the severity of MS (P < 0.001, r = 0.65). Analytical models showed that SEA played the most important role (among all included factors that affect on EDSS) in the severity of MS. The SEA of C. albicans in MS patients was significantly more than the healthy controls. The results suggest that the level of SEA of proteinase A and probably the capacity of C. albicans isolates to invade the host tissue is associated with the severity of MS.     

Immunomodulatory function of Treg-derived exosomes is impaired in patients with relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease which is characterized by neuroaxonal degeneration in the central nervous system. Impaired function of regulatory T cells (Tregs) is believed to be an underlying pathogenic mechanism in MS. Tregs is able to release exosomes, which contain a considerable amount of protein and RNA. Exosomes are capable of transporting their content to other cells where the released content exerts biological functions. Here, we investigated whether Tregs exosomes of RRMS patients or healthy controls might regulate the proliferation or survival of T lymphocytes. Regulatory T cells derived from MS patients or healthy controls were cultured for 3 days and exosomes were purified from supernatants. Treg-derived exosomes were co-cultured with conventional T cells (Tconv). The percentages of Tconv proliferation and apoptosis were measured. Our findings showed that the percentage of proliferation suppression induced by exosomes in patients compared to healthy controls was 8.04?±?1.17 and 12.5?±?1.22, respectively, p value?=?0.035. Moreover, the rate of Tconv apoptosis induced by exosome of MS patient was less than healthy controls (0.68?±?0.12 vs. 1.29?±?0.13; p value?=?0.015). Overall, Treg-derived exosomes from MS patients and healthy controls suppressed the proliferation and induced apoptosis in Tconv. However, the effect of MS-derived exosomes was significantly less than healthy controls. Our results point to an alternative Treg inhibitory mechanism which might be important in immunopathogenesis of MS. Although, the cause of the exosomal defect in MS patients is unclear, manipulation of patients’ Treg-derived exosomes to restore their suppressive activity might be considered as a potential therapeutic approach.

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Pharmacokinetic/Pharmacodynamic Considerations of Beta-Lactam Antibiotics in Adult Critically Ill Patients

Purpose of Review

Beta-lactam antibiotics are commonly prescribed in critically ill patients for a variety of infectious conditions. Our understanding of how critical illness alters beta-lactam pharmacokinetics/pharmacodynamics (PK/PD) is rapidly evolving.

Recent Findings

There is a growing body of literature in adult patients demonstrating that physiological alterations occurring in critically ill patients may limit our ability to optimally dose beta-lactam antibiotics to reach these PK/PD targets. These alterations include changes in volume of distribution and renal clearance with multiple, often overlapping causative pathways, including hypoalbuminemia, renal replacement therapy, and extracorporeal membrane oxygenation. Strategies to overcome these PK alterations include extended infusions and therapeutic drug monitoring. Combined data has demonstrated a possible survival benefit associated with extending beta-lactam infusions in critically ill adult patients.

Summary

This review highlights research on physiological derangements affecting beta-lactam concentrations and strategies to optimize beta-lactam PK/PD in critically ill adults.

     

Attachment and Penetration of Acyclovir‐resistant Herpes Simplex Virus are Inhibited by Melissa officinalis Extract

Medicinal plants are increasingly of interest as novel source of drugs for antiherpetic agents, because herpes simplex virus (HSV) might develop resistance to commonly used antiviral drugs. An aqueous extract of Melissa officinalis and the phenolic compounds caffeic acid, p‐coumaric acid and rosmarinic acid were examined for their antiviral activity against herpes simplex virus type 1 (HSV‐1) acyclovir‐sensitive and clinical isolates of acyclovir‐resistant strains in vitro. When drugs were added during the intracellular replication of HSV‐1 infected cells, no antiviral effect was observed by plaque reduction assay. However, Melissa extract interacted directly with free viral particles of two acyclovir‐resistant HSV strains at low IC₅₀ values of 0.13 and 0.23 µg/mL and high selectivity indices of 2692 and 1522, respectively. The Melissa extract and rosmarinic acid inhibited HSV‐1 attachment to host cells in a dose‐dependent manner for acyclovir‐sensitive and acyclovir‐resistant strains. These results indicate that mainly rosmarinic acid contributed to the antiviral activity of Melissa extract. Penetration of herpes viruses into cells was inhibited by Melissa extract at 80% and 96% for drug‐sensitive and drug‐resistant viruses, respectively. Melissa extract exhibits low toxicity and affects attachment and penetration of acyclovir‐sensitive and acyclovir‐resistant HSVs in vitro. Copyright © 2014 John Wiley & Sons, Ltd.     

The discovery of a Persian family with a form of Birt–Hogg–Dubé syndrome lacking the typical cutaneous stigmata of the syndrome

PurposeThis study was performed in 24 members of a family with spontaneous pneumothorax to test clinical suspicion of Birt–Hogg–Dubé syndrome (BHDS).MethodsComputed tomography scan was performed for confirmation of pneumothorax, while genetic tests were done using real-time quantitative polymerase chain reaction.ResultsGenetic studies showed a deletion of exon 1 in the FLCN gene in the index case as well as nine other individuals, including two with clinical phenotypes of pneumothorax and seven who are symptom-free to date.ConclusionsProper imaging and taking accurate family history could be the keys to test clinical suspicion in some syndromes, including BHDS.     

Analysis of apoptosis and expression of genes related to apoptosis in cultures of follicles derived from vitrified and non-vitrified ovaries

The aim of this study was to evaluate the incidence of apoptosisafter in vitro culture of isolated follicles derived from vitrifiedand non-vitrified ovaries. Mouse ovaries were vitrified andtheir pre-antral follicles were mechanically isolated and culturedfor 10 days. Growth and survival rates of the follicles wereassessed during the culture period and the ultrastructure ofthe follicles was studied. The expression of p53, Bcl-2, Bax,Fas, FasL and survivin were analyzed by real-time RT–PCRin different follicular developmental stages. The percentagesof apoptotic and necrotic cells were determined using a fluorescein-activatedcell sorting (FACS) technique. There were no differences betweenthe growth and survival rates of follicles in the vitrifiedand non-vitrified groups. All of the evaluated genes were expressedin the pre-antral, large pre-antral and antral follicles inboth groups, except Fas mRNA, which was not expressed in thepre-antral follicles. The expression of p53, Bcl2, Bax and FasLmRNA was similar in vitrified and non-vitrified groups; however,Fas mRNAs were more strongly expressed in the antral folliclesof the vitrified group than of the control group (P < 0.05).The expression of survivin 140 was lower in the antral folliclesof the vitrified group than of the control group (P < 0.05).FACS analysis showed that the percentage of intact cells waslower in the vitrified group than in the non-vitrified group(P < 0.05). This study demonstrated no signs of apoptosisultrastructurally in cultured follicles; however, vitrificationwas shown to affect the expression of some genes related toapoptosis.     

The interest of 18FDG-PET in the management of testicular cancer

The key to prognosis. Initial staging and early recurrence diagnosis are key parameters in the treatment and outcome of testicular cancer. Initial staging. It is difficult using conventional modalities, which can miss node involvement and are non-specific since enlargement does not rhyme with involvement. 18FDG PET improves the accuracy of initial staging. Residual mass and recurrences. Existence of residual mass or enhancement of its Volume in the presence of an otherwise beneficial chemotherapy is difficult to manage. Several studies have demonstrated the value of 18FDG imaging in such cases. As for follow-up whole body 18FDG can prevent multiple diagnostic imaging and can diagnose recurrences with greater diagnostic accuracy than with other imaging modalities.