Discrimination of Entamoeba spp. in children with dysentery

Aim: The present study was performed in order to differentiate E. histolytica and E. dispar in children from Gorgan city, using a PCR method. Background: Differential detection of two morphologically indistinguishable protozoan parasites Entamoeba histolytica and E. dispar has a great clinical and epidemiological importance because of potential invasive pathogenic E. histolytica and non-invasive parasite E. dispar. Patients and methods: One hundred and five dysentery samples were collected from children hospitalized in Taleghani hospital in Gorgan city. The fecal specimens were examined by light microscopy (10X then 40X) to distinguish Entamoeba complex. A single round PCR amplifying partial small-subunit rRNA gene was performed on positive microscopy samples to differentiate E. histolytica/ E. dispar and E. moshkovskii from each other. Results: Twenty-five specimens (23.8%) were positive for Enramoeba complex in direct microscopic examination. PCR using positive controls indicated E. histolytica and E. dispar in two (2/25, 8%) and three (3/25, 12%) samples, respectively. Conclusion: There is a warrant to performing molecular diagnosis for stool examination at least in hospitalized children in order to prevent incorrect reports from laboratories and consequently mistreating by physicians. © 2014 RIGLD, Research Institute for Gastroenterology and Liver Diseases

Prevalence and genetic characterization of Cryptosporidium spp. In diarrheic children from Gonbad Kavoos city, Iran

Background: Cryptosporidium is an intestinal protozean parasite causing water-borne and foodborne outbreaks of diarrheal diseases. The present study was per-formed in order to find prevalence and subtypes of Cryptosporidium among children with diarrhea in Gonbad Kavoos City, Northern Iran. Methods: Diarrheic samples were collected from 547 children. The initial parasi-tological diagnosis was made based on detection of oocysts using the modified Ziehl-Neelsen acid-fast staining method. The positive microscopically samples were selected for sequence analysis of partial 60 kDa glycoprotein (gp60) gene. Results: Out of 547 collected samples, 27 (4.94) were positive for Cryptosporid-ium oocysts. Fifteen from 27 positive samples successfully amplified in PCR. Se-quences analysis of gp60 gene in 15 Cryptosporidium isolates revealed that all of them (100) were C. parvum. The results showed three subtypes of IIa subtype family (7 cases) including IIaA16G2R1, IIaA17G1R1, IIaA22G3R1 and one subtype of IId subtype family (8 cases). The most common allele was IId A17G1d (53.3). Conclusion: The predominance of zoonotic subtype families of C. parvum species (IIa, IId) in the present study is in concordance with previous studies in Iran and emphasizes the significance of zoonotic transmission of cryptosporidiosis in the country. © 2015, Tehran University of Medical Sciences (TUMS). All rights Reserved

Tailoring the excitation of localized surface plasmon-polariton resonances by focusing radially-polarized beams

We study the interaction of focused radially-polarized light with metal nanospheres. By expanding the electromagnetic field in terms of multipoles, we gain insight on the excitation of localized surface plasmon-polariton resonances in the nanoparticle. We show that focused radially-polarized beams offer more opportunities than a focused plane wave or a Gaussian beam for tuning the near- and far-field system response. These results find applications in nano-optics, optical tweezers, and optical data storage.Comment: 4 pages, 3 figure

The effect of quinapril on the aortic contractile response of streptozotocin-diabetic rats

Angiotensin-converting enzyme (ACE) inhibitors appear to correct many of the abnormalities associated with the vascular dysfunction found in diabetic patients. In this respect, quinapril is a unique ACE inhibitor with multiple protective effects. The present study was carried out to investigate the effect of intraperitoneal administration of quinapril on the aortic reactivity of streptozotocin (STZ)-diabetic rats. For this purpose, male Wistar rats received one injection of streptozotocin (STZ), 60 mg/kg, to induce diabetes. Three days after STZ injection, rats were treated with quinapril (2 mg/kg/day) for 4 weeks, after that aortic reactivity to vasoactive agents were compared with those of untreated diabetic rats or non-diabetic control rats. For this purpose, contractile response to phenylephrine (PE) was obtained from aortic rings. Concentration-response curves from quinapril-treated diabetic rats to PE in the presence and absence of endothelium were attenuated as compared to vehicle-treated diabetics. Therefore, the 4-week treatment of diabetic rats with quinapril could prevent the functional changes in vascular reactivity in diabetic rats

Plasmon spectra of nanospheres under a tightly focused beam

We study the modification of the far-field cross sections and the near-field enhancement for gold and silver nanospheres illuminated by a tightly focused beam. Using a multipole-expansion approach we obtain an analytical solution to the scattering problem and provide insight on the effects of focusing on the optical response. Large differences with respect to Mie theory are found especially when the nanoparticle supports quadrupole or higher-order resonances.Comment: 19 pages, 7 figure

Light scattering by an oscillating dipole in a focused beam

The interaction between a focused beam and a single classical oscillating dipole or a two-level system located at the focal spot is investigated. In particular, the ratio of the scattered to incident power is studied in terms of the oscillator's scattering cross section and the effective focal area. Debye diffraction integrals are applied to calculate it and results are reported for a directional dipolar wave. Multipole expansion of the incident beam is then considered and the equivalence between this and the Debye diffraction approach is discussed. Finally, the phase change of the electric field upon the interaction with a single oscillator is studied.Comment: 9 pages, 6 figure

The Association Between Borna Disease Virus and Chronic Fatigue Syndrome: A Systematic Review and Meta-Analysis

Context: Several studies have controversial results regarding the association between Borna disease virus (BDV) and chronic fatigue syndrome (CFS). The present systematic review and meta-analysis investigated the association between CFS and BDV. Evidence Acquisition: The present study was conducted based on the PRISMA guidelines for systematic review and meta-analysis studies. To avoid bias, all procedures of the study were performed by two researchers independently. A comprehensive search was performed using online databases, including PubMed, Scopus, Embase, PsycINFO, science Direct, Cochrane Library, web of science, and Google scholar using the MeSH keywords until December 12th, 2016. Heterogeneity among studies was evaluated using Cochran's Q test I-2 Index. Finally, the random effect model was used for combined Odds Ratio (OR) using Review Manger software version 5.3.5. Results: Among 9 eligible studies comprising 610 cases and 2176 controls, the total OR for association between BDV and CFS was estimated to be 10.41 (95 confidence interval CI: 4.24 - 25.55, P < 0.0001). For subgroup analysis by the diagnostic methods (ELISA, RT-PCR, and Western blot), OR was 2.47 (95% CI: 0.77 - 7.96, P=0.13), 12.20 (95% CI: 1.66 - 89.57, P=0.01), and 28.36 (95% CI: 3.76- 213.85, P=0.001), respectively (test for subgroup differences: P=0.08; I-2=59.5). Subgroup analysis for BDV and CFS association by antigens and antibodies had an OR of 12.20 (1.66, 89.57) and 8.20 (3.32, 20.22), respectively (test for subgroup differences: P=0.72; I-2=0). Conclusions: This study supports the association between BDV and CFS and shows the role of viral agents in etiology of CFS. Therefore, viral agents may play a role in the etiology of neuropsychiatric disorders

First Report of Vannellidae Amoebae (Vannella Spp.) Isolated From Biofilm Source

Background: Members of the Vannellidae family are free-living amoebae (FLA) distributed mainly in water and soil sources. The present study reports the first isolation of this genus in the biofilm source from hospital environment in Tehran, Iran.Methods: Biofilm samples were collected from hospital environment. Cultivation was performed in non-nutrient agar covered with a heat-killed Escherichia coli. Cloning of the suspected amoe­bae was done. PCR amplification and Homology analysis using the Basic Local Alignment Search Tool (BLASTn) was performed to search for the most similar reference sequences.Results: Microscopic examination showed numerous fan-shaped amoebae and peculiar cysts differ­ent to the usual shape of typical FLA. Sequence analysis of the PCR- product revealed that the suspected amoebae are highly homologous with Vannella spp. gene (99% identity and 100% query coverage) available in the gene bank database.Conclusion: Although Vannella spp. is not proved to be pathogenic itself, but they are capable of har­boring pathogenic intracellular organisms such as Microsporidian parasites. Thus, identifica­tion of such amoebae can be of clinical importance, as they could lead to transmission of other pathogens to human

Perfect Reflection of Light by an Oscillating Dipole

We show theoretically that a directional dipole wave can be perfectly reflected by a single point-like oscillating dipole. Furthermore, we find that in the case of a strongly focused plane wave up to 85 % of the incident light can be reflected by the dipole. Our results hold for the full spectrum of the electromagnetic interactions and have immediate implications for achieving strong coupling between a single propagating photon and a single quantum emitter.Comment: 3 figure