When R > 0.8 R0: fluorescence anisotropy, non-additive intensity, and cluster size

Assembly and clustering feature in many biological processes and homo-FRET and fluorescence anisotropy can assist in estimating the aggregation state of a system. The distance dependence of resonance energy transfer is well described and tested. Similarly, assessment of cluster size using steady state anisotropy is well described for non-oriented systems when R 0.8 R0. Fused trimeric DNA clusters labelled with fluorescein were engineered to provide inter-fluorophore distances from 0.7 to 1.6 R/R0 and intensity and anisotropy were measured. These constructs cover a range where anisotropy effects depend on distance. Analytical expressions were derived for fully labelled and fractionally labelled clusters and the experimental results analysed. The experimental results showed that: 1) the system underwent distance dependent quenching; 2) when incompletely labelled both doubly and triply labelled forms could be assessed to obtain distance dependent intensity factors; 3) the anisotropy behaviour of a multiply labelled cluster of a particular size depends on the behaviour of the fluorophores and their distance in a cluster. This work establishes that when emission intensity data are available the analytically useful range for investigating clusters does not have to be restricted to R < 0.8 R0 and is applicable to cases where the anisotropy of a cluster of N fluorophores is not well approximated by r1/N

Short communication: Cadmium determination in two flat fishes from two fishery regions in north of the Persian Gulf

Heavy metals are natural trace components of the aquatic environment, but their levels have increased due to industrial agriculture, mining activities, industrial activity, shipping accident. Pollution studies in the ROPME area including the Persian Gulf and the Oman Sea are extremely important because this region is shallow, semi-enclosed, and has a very high evaporation rate and poor flushing characteristics. Other Iranian scientists reported the pollution from inland water but our study was the first on evaluation of Cadmium pollution from northern coastal waters of the Persian Gulf, belonging to the Iranian coastlines. The aim of this study was to examine the quality of local seafood in terms of heavy metal contamination by examining the two commercial fish species, Euryglossa orientalis and Psettodes erumei through the determination of Cd concentration levels in the muscle and liver tissues of the fish, monitoring the ROPME region, and investigating the relationship between fish size and metal concentration in the different tissues of these two flat fishes

Theoretical and lab based studies of fluorescence anisotropy toward the analysis of multiple homo-FRET pairs

Many biological functions, involve assembly of proteins. Protein clustering has an important role in signal transduction through the cell membrane. Model systems that simulate receptor aggregation can be used to monitor oligomerization. Techniques based on homo-FRET can reveal the aggregation state of receptor proteins because homo-FRET causes the fluorescence anisotropy of the system to decrease when the number of identical fluorophores within energy transfer distance increases. Theories that describe these systems apply an assumption of equal fluorescence efficiency for all sites [1, 2], that means emission intensity of fluorophores do not change when in close proximity with each other in a cluster. However, most fluorophores in close proximity show either self-quenching or emission enhancement. Previous theories that were devised to study fractional labelling of proteins were only applicable to cases where the distances between the labels were less than 0.8Ro, while in practice the distances between the dyes are more in protein aggregates. Three different systems were chosen to mimic aggregation of fluorescently labelled receptor proteins and analytical expressions were presented for fully labelled and fractionally labelled clusters and the experimental results from the three systems were analyzed. The systems were: a)stochastically labelled BSA containing up to 24 FITC, b) DNA fused trimeric clusters of fluorescein (stochastically labelled), and c)DNA Holliday junctions labelled with fluorescein (in a range of sizes). The inter-probe distances on the DNA constructs were designed to be up to 1.5 Ro to cover cluster sizes of larger protein clusters. The experimental results showed that: 1) none of the clustered species followed the assumption of equal fluorescence efficiency, 2) by applying the assumption of equal fluorescence efficiency, anisotropies were under-predicted and cluster sizes were under-estimated in systems that show quenching and 3) anisotropy behaviour of a multiply labelled cluster of a particular size depends on the behaviour of the fluorophores and their distance in a cluster. As a result of the theory presented here, the size of larger clusters than currently considered possible can be determined; if they are strongly quenched and their fractional labelling is carefully selected

Diagnosis of premature rupture of membranes by the detection of thyroid hormones in vaginal secretions

Background: Premature rupture of membranes (PROM) and preterm PROM (PPROM) are the rupture of the fetal chorioamniotic membranes before the onset of labor contractions. Objectives: To evaluate whether detection of thyroid hormones in vaginal washouts can be used to diagnose premature rupture of membranes (PROM). Patients and Methods: Total T4 (thyroxin), total T3 (triiodothyronine), and free T4 concentrations in vaginal washouts were analyzed in 45 women with the diagnosis of PROM and compared with 45 normal pregnancies (controls). A Student�s t-test was used for comparison of thyroid hormone values and a ROC curve was used for analyzing the diagnostic accuracy Results: There were no differences between the patients with PROM and the control women regarding maternal age, gestational age, and parity. The mean concentration of total T4 in the PROM group and the control subjects were 2.1 ± 1.3 jig/mL and 1.55 ± 0.58 jig/, respectively (P = 0.01). Total T3 concentration in the PROM group was significantly higher compared to the controls (1.28 ± 0.42 ng/ vs. 0.8 ± 0.26 ng/, P < 0.0001). Also, free T4 concentration was significantly higher in the PROM group as compared with the controls (0.026 ± 0.034 ng/ vs.0.007 ± 0.004 ng/, P < 0.0001). The ROC curve analysis showed that total T4=1.685 jig/ had a sensitivity of 62, specificity of 76, positive predictive value (PPV) of 71.8, and negative predictive value (NPV) of 66.7. Total T3 = 0.82 ng/ gave a sensitivity of 91, specificity of 64, PPV of 72, and NPV of 87.8. Free T4 = 0.01 ng/ gave a sensitivity of 51, specificity of 82, PPV of 74.2, and NPV of 62.7. The best cutoff values were total T4 = 1.685 ng/, total T3 = 0.82 ng/, and free T4 = 0.01 ng/. Conclusions: Detecting total T4, total T3, and free T4 in vaginal washouts of patients suspected of PROM suspected is a simple, available, rapid, and inexpensive method for the diagnosis of PROM. However, a combination of three tests is recommended. © 2015, Shiraz University of Medical Sciences

Methyl Mercury Induced Changes in the Serum Proteins of Bluegills – Lepomis Macrochirus (Teleostei)

Author Institution: Department of Biological Sciences, Kent State UniversityThere were qualitative and quantitative changes in the serum proteins of bluegills, Lepomis macrochirus, exposed to 8.728 X 10~4 ppb (W/V) of methyl mercury (MeHg) for 24, 48, and 72 hr. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of serum proteins revealed significant changes in the qualitative and quantitative profiles at 24 and 48 hr. However, at 72 hr a trend to return to control levels was noted. The data suggest that at the dose tested, MeHg produced repairable lesions in certain tissues or organs of bluegills

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

Risk factors and consequent outcomes of placenta previa: Report from a referral center

Because of an unknown factor, the frequency of complicated pregnancy with placenta previa has been raised during past decade. This study was designed to deepen our understanding of risk factors and outcomes of placenta previa in our country. This study investigated 694 cases of placenta previa comparing with 600 healthy pregnant women with not overlie placenta in two referral and tertiary Obstetrics and Gynecological Hospital in Iran on the basis of the clinical and para-clinical analysis, in order to find the probable risk factors for occurrence of placenta previa and its effect on maternal and neonatal complications. The most important risk factor for the occurrence of placenta previa was advanced maternal age (P<0.001) and history of stillbirth (OR=117.2, CI=58.3-236.0). In the other hand, the most substantial outcome of this disorder was a reduction of gestational age (P<0.001) and low birth weight neonatally (P<0.001). The conservative follow-up should be programmed for women with placenta previa based on the type of risk factors which can provide the best possible management to decrease the morbidity and mortality of their related complications. © 2016 Tehran University of Medical Sciences. All rights reserved

Assessment of subclinical left ventricular dysfunction in patients with chronic mitral regurgitation using torsional parameters described by tissue doppler imaging

Background: Left ventricular (LV) twist is due to oppositely directed apical and basal rotation and has been proposed as a sensitive marker of LV function. We sought to assess the impact of chronic pure mitral regurgitation (MR) on the torsional mechanics of the left human ventricle using tissue Doppler imaging. Methods: Nineteen severe MR patients with a normal LV ejection fraction and 16 non-MR controls underwent conventional echocardiography and apical and basal short-axis color Doppler myocardial imaging (CDMI). LV rotation at the apical and basal short-axis levels was calculated from the averaged tangential velocities of the septal and lateral regions, corrected for the LV radius over time. LV twist was defined as the difference in LV rotation between the two levels, and the LV twist and twisting/untwisting rate profiles were analyzed throughout the cardiac cycle. Results: LV twist and LV torsion were significantly lower in the MR group than in the non-MR group (10.38 ° ± 4.04 ° vs. 13.95 ° ± 4.27 °; p value = 0.020; and 1.29 ± 0.54 °/cm vs. 1.76 ± 0.56 °/cm; p value = 0.021, respectively), both suggesting incipient LV dysfunction in the MR group. Similarly, the untwisting rate was lower in the MR group (-79.74 ± 35.97 °/s vs.-110.96 ± 34.65 °/s; p value = 0.020), but there was statistically no significant difference in the LV twist rate. Conclusion: The evaluation of LV torsional parameters in MR patients with a normal LV ejection fraction suggests the potential role of these sensitive variables in assessing the early signs of ventricular dysfunction in asymptomatic patients