Sublethal effects of abamectin on the biological performance of the predatory mite, <Emphasis Type="Italic">Phytoseius plumifer</Emphasis> (Acari: Phytoseiidae)

Traditionally estimating pesticide effects by measuring only lethal effect may underestimate the total negative effect on beneficial arthropods and sublethal effects should be assessed to estimate the total effect of their applications. In this study, sublethal effect of the acaricide abamectin (Vermectin^® 1.8% EC, Giah, Iran) on the predatory mite Phytoseius plumifer (Canestrini &; Fanzago) (Acari: Phytoseiidae) fed on Tetranychus urticae Koch was assessed in laboratory conditions. The adult predators were exposed to the residues of the acaricide on fig leaves and the LC₅₀ value was determined based on a concentration–response analysis. The results showed that sublethal concentrations (LC₁₀, LC₂₀ and LC₃₀) of abamectin severely affected the fecundity and longevity of the treated females of P. plumifer. Furthermore, reproductive and life table parameters of the subsequent generation were affected. The results indicated that adverse effects of abamectin on population growth of P. plumifer were significant, so the results from this study can be used to develop approximate guidelines for the use of abamectin in order to minimize their impact on P. plumifer and related natural enemies.     

The role of nodules in the tolerance of common bean to iron deficiency

Iron is vital for the establishment and function of symbiotic root nodules of legumes. Although abundant in the environment, Fe is often a limiting nutrient for plant growth due to its low solubility and availability in some soils. We have studied the mechanism of iron uptake in the root nodules of common bean to evaluate the role of nodules in physiological responses to iron deficiency. Based on experiments using full or partial submergence of nodulated roots in the nutrient solution, our results show that the nodules were affected only slightly under iron deficiency, especially when the nodules were submerged in nutrient solution in the tolerant cultivar. In addition, fully submerged root nodules showed enhanced acidification of the nutrient solution and showed higher ferric chelate reductase activity than that of partially submerged roots in plants cultivated under Fe deficiency. The main results obtained in this work suggest that in addition to preferential Fe allocation from the root system to the nodules, this symbiotic organ probably develops some mechanisms to respond to iron deficiency. These mechanisms were implied especially in nodule Fe absorption efficiency and in the ability of this organ to take up Fe directly from the medium.     

Ameliorative Effect of Bone Marrow-Derived Stem Cells on Injured Liver of Mice Infected with Schistosoma mansoni

The technique of stem cells or hepatocytes transplantation has recently improved in order to bridge the time before whole-organ liver transplantation. In the present study, unfractionated bone marrow stem cells (BMSCs) were harvested from the tibial and femoral marrow compartments of male mice, which were cultured in Dulbecco''s modified Eagle''s medium (DMEM) with and without hepatocyte growth factor (HGF), and then transplanted into Schistosoma mansoni-infected female mice on their 8th week post-infection. Mice were sacrificed monthly until the third month of bone marrow transplantation, serum was collected, and albumin concentration, ALT, AST, and alkaline phosphatase (ALP) activities were assayed. On the other hand, immunohistopathological and immunohistochemical changes of granuloma size and number, collagen content, and cells expressing OV-6 were detected for identification of liver fibrosis. BMSCs were shown to differentiate into hepatocyte-like cells. Serum ALT, AST, and ALP were markedly reduced in the group of mice treated with BMSCs than in the untreated control group. Also, granuloma showed a marked decrease in size and number as compared to the BMSCs untreated group. Collagen content showed marked decrease after the third month of treatment with BMSCs. On the other hand, the expression of OV-6 increased detecting the presence of newly formed hepatocytes after BMSCs treatment. BMSCs with or without HGF infusion significantly enhanced hepatic regeneration in S. mansoni-induced fibrotic liver model and have pathologic and immunohistopathologic therapeutic effects. Also, this new therapeutic trend could generate new hepatocytes to improve the overall liver functions.     

Impact of Protein Domains on PE_PGRS30 Polar Localization in Mycobacteria

PE_PGRS proteins are unique to the Mycobacterium tuberculosis complex and a number of other pathogenic mycobacteria. PE_PGRS30, which is required for the full virulence of M. tuberculosis (Mtb), has three main domains, i.e. an N-terminal PE domain, repetitive PGRS domain and the unique C-terminal domain. To investigate the role of these domains, we expressed a GFP-tagged PE_PGRS30 protein and a series of its functional deletion mutants in different mycobacterial species (Mtb, Mycobacterium bovis BCG and Mycobacterium smegmatis) and analysed protein localization by confocal microscopy. We show that PE_PGRS30 localizes at the mycobacterial cell poles in Mtb and M. bovis BCG but not in M. smegmatis and that the PGRS domain of the protein strongly contributes to protein cellular localization in Mtb. Immunofluorescence studies further showed that the unique C-terminal domain of PE_PGRS30 is not available on the surface, except when the PGRS domain is missing. Immunoblot demonstrated that the PGRS domain is required to maintain the protein strongly associated with the non-soluble cellular fraction. These results suggest that the repetitive GGA-GGN repeats of the PGRS domain contain specific sequences that contribute to protein cellular localization and that polar localization might be a key step in the PE_PGRS30-dependent virulence mechanism.     

Highlighting Levels of Indoxyl Sulphate among Critically Ill Patients with Acute Nephrotoxicity; Correlations Between Indoxyl Sulphate Levels and Patients’ Characteristics

Background:Many animal studies suggested that the uremic toxin indoxyl sulphate can add to renal damage following induced nephrotoxicity and this effect has not been proved in patients with such complication. Methods:This is a prospective, case-control, and an observational study conducted on 74 critically ill patients with acute nephrotoxicity. It was designed to measure serum levels of indoxyl sulphate on the day of enrollment and over the course of their illness using high performance liquid chromatography (HPLC-UV) and to test the correlation between these levels and patient’s demographics, clinical characteristics, physiological variables, and their outcomes.Results:Critically ill patients with acute nephrotoxicity had significantly higher total (tIS) and free (fIS) indoxyl sulphate than healthy controls and significantly lower than patients with end-stage renal disease (ESRD). Although, no correlation was found between tIS or fIS and mortality, among survivors, tIS, fIS, creatinine and eGFR were independently associated with no renal recovery.Conclusion:Serum indoxyl sulphate levels were elevated in critically ill patients with acute nephrotoxicity. There is an association between high levels of indoxyl sulphate and no renal-recovery outcome among survivors of acute nephrotoxicity. Early removal of indoxyl sulphate from patients’ blood may improve their outcomes.Key Words: HPLC, Indoxyl sulphate, Mortality, Prognosis, Toxic acute kidney injury     

FDTD analysis of a noninvasive hyperthermia system for brain tumors

ABSTRACT: BACKGROUND: Hyperthermia is considered one of the new therapeutic modalities for cancer treatment and is based on the difference in thermal sensitivity between healthy tissues and tumors. During hyperthermia treatment, the temperature of the tumor is raised to 40--4[DEGREE SIGN]C for a definite period resulting in the destruction of cancer cells. This paper investigates design, modeling and simulation of a new non-invasive hyperthermia applicator system capable of effectively heating deep seated as well as superficial brain tumors using inexpensive, simple, and easy to fabricate components without harming surrounding healthy brain tissues. METHODS: The proposed hyperthermia applicator system is composed of an air filled partial half ellipsoidal chamber, a patch antenna, and a head model with an embedded tumor at an arbitrary location. The irradiating antenna is placed at one of the foci of the hyperthermia chamber while the center of the brain tumor is placed at the other focus. The finite difference time domain (FDTD) method is used to compute both the SAR patterns and the temperature distribution in three different head models due to two different patch antennas at a frequency of 915 MHz. RESULTS: The obtained results suggest that by using the proposed noninvasive hyperthermia system it is feasible to achieve sufficient and focused energy deposition and temperature rise to therapeutic values in deep seated as well as superficial brain tumors without harming surrounding healthy tissue. CONCLUSIONS: The proposed noninvasive hyperthermia system proved suitable for raising the temperature in tumors embedded in the brain to therapeutic values by carefully selecting the systems components. The operator of the system only needs to place the center of the brain tumor at a pre-specified location and excite the antenna at a single frequency of 915 MHz. Our study may provide a basis for a clinical applicator prototype capable of heating brain tumors.     

Enhanced Thermal Stability and Biocompatibility of Gold Nanorods by Graphene Oxide

In the present study, the effect of nanosized graphene oxide layer on thermal stability and biocompatibility of gold nanorods has been examined. The graphene oxide-wrapped gold nanorods were prepared by electrostatic interaction between negatively charged graphene oxide and positively charged nanorods. The resulting nanohybrids were then heated at different time intervals to 95 °C in a water bath to assess the effect of heat on the rods morphology. The structural changes in gold nanorods were monitored via UV-Vis spectroscopy measurements and transmission electron microscopy images. In similar experiments, the graphene oxide used to wrap gold nanorods was reduced by ascorbic acid in a 95 °C water bath. Our results indicate that while bare gold nanorods are highly vulnerable to elevated temperatures, graphene oxide and reduced graphene oxide-coated gold nanorods remain thermally stable with no structural changes. We also confirmed that the enhanced thermal stability is highly dependent on the concentration of deposited graphene oxide available on the surface of the gold nanorods. In addition, we performed an MTT (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazoliumbromide) assay to make a comparison between the cytotoxicity of the nanohybrids and their primary building blocks on human dermal fibroblast cells as a normal cell line. We found evidence that graphene oxide can enhance the biocompatibility of the rods through covering toxic chemicals on the surface of them.

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Molecular diagnosis of Helicobacter pylori antibiotic resistance in the Taif region,Saudi Arabia

Success in eradication of Helicobacter pylori is declining globally because H. pylori has developed resistance against most of the antibiotics proposed for eradication regimens, mainly through point mutations. The present study included 200 patients with dyspepsia attending Taif Hospital. Gastric biopsies were obtained during gastroscopy and subjected to rapid urease testing. Molecular methods were used to confirm diagnoses of H. pylori infection and to identify resistance gene variants of four antibiotics; namely, clarithromycin, metronidazole, fluoroquinolones and tetracycline (23S rRNA, gyrA, rdxA and 16S rRNA respectively). Of all investigated patients, Molecular diagnoses were made in 143 of all investigated patients; thus, the prevalence was .5%. The overall rate of resistance to clarithromycin among the H. pylori‐positive patients was high (39.9%) and the rate of resistance significantly greater (48.2%) among the secondary resistance group, secondary resistance being defined as resistance as a result of previous exposure to the relevant antibiotic. The rate of resistance to fluoroquinolones was considered moderate; the difference in rate of resistance between the primary and secondary resistance groups (8.4% and 9.5%, respectively) was not significant Also, there was a low prevalence of both primary and the secondary tetracycline resistance in the study cohort. In contrast, the prevalence of metronidazole resistance was considered high with no significant difference between the two resistance groups. H. pylori showed an increased prevalence of resistance to all four of the commonly used therapeutic agents. Thus, eradication therapy should be based on the regional results of susceptibility testing. Moreover, treatment tailored according to individually determined H. pylori susceptibility may be a reasonable future goal.