Characterization of the tissue‐level Ca2+ signals in spontaneously contracting human myometrium

In the labouring uterus, millions of myocytes forming the complex geometrical structure of myometrium contract in synchrony to increase intrauterine pressure, dilate the cervix and eventually expel the foetus through the birth canal. The mechanisms underlying the precise coordination of contractions in human myometrium are not completely understood. In the present study, we have characterized the spatio‐temporal properties of tissue‐level [Ca²⁺]_i transients in thin slices of intact human myometrium. We found that the waveform of [Ca²⁺]_i transients and isotonic contractions recorded from thin slices was similar to the waveform of isometric contractions recorded from the larger strips in traditional organ bath experiments, suggesting that the spatio‐temporal information obtained from thin slices is representative of the whole tissue. By comparing the time course of [Ca²⁺]_i transients in individual cells to that recorded from the bundles of myocytes we found that the majority of myocytes produce rapidly propagating long‐lasting [Ca²⁺]_i transients accompanied by contractions. We also found a small number of cells showing desynchronized [Ca²⁺]_i oscillations that did not trigger contractions. The [Ca²⁺]_i oscillations in these cells were insensitive to nifedipine, but readily inhibited by the T‐type Ca²⁺ channel inhibitor NNC55‐0396. In conclusion, our data suggest that the spread of [Ca²⁺]_i signals in human myometrium is achieved via propagation of long‐lasting action potentials. The propagation was fast when action potentials propagated along bundles of myocytes and slower when propagating between the bundles of uterine myocytes.     

Interaction of an anticancer benzopyrane derivative with DNA: Biophysical,biochemical, and molecular modeling studies

BackgroundSIMR1281 is a potent anticancer lead candidate with multi- target activity against several proteins; however, its mechanism of action at the molecular level is not fully understood. Revealing the mechanism and the origin of multitarget activity is important for the rational identification and optimization of multitarget drugs.MethodsWe have used a variety of biophysical (circular dichroism, isothermal titration calorimetry, viscosity, and UV DNA melting), biochemical (topoisomerase I & II assays) and computational (molecular docking and MD simulations) methods to study the interaction of SIMR1281 with duplex DNA structures.ResultsThe biophysical results revealed that SIMR1281 binds to dsDNA via an intercalation-binding mode with an average binding constant of 3.1 × 10⁶ M⁻¹. This binding mode was confirmed by the topoisomerases' inhibition assays and molecular modeling simulations, which showed the intercalation of the benzopyrane moiety between DNA base pairs, while the remaining moieties (thiazole and phenyl rings) sit in the minor groove and interact with the flanking base pairs adjacent to the intercalation site.ConclusionsThe DNA binding characteristics of SIMR1281, which can disrupt/inhibit DNA function as confirmed by the topoisomerases' inhibition assays, indicate that the observed multi-target activity might originate from ligand intervention at nucleic acids level rather than due to direct interactions with multiple biological targets at the protein level.General significanceThe findings of this study could be helpful to guide future optimization of benzopyrane-based ligands for therapeutic purposes.     

A distance-type measure approach to the analysis of copy number variation in DNA sequencing data

Background

The next generation sequencing technology allows us to obtain a large amount of short DNA sequence (DNA-seq) reads at a genome-wide level. DNA-seq data have been increasingly collected during the recent years. Count-type data analysis is a widely used approach for DNA-seq data. However, the related data pre-processing is based on the moving window method, in which a window size need to be defined in order to obtain count-type data. Furthermore, useful information can be reduced after data pre-processing for count-type data.

Results

In this study, we propose to analyze DNA-seq data based on the related distance-type measure. Distances are measured in base pairs (bps) between two adjacent alignments of short reads mapped to a reference genome. Our experimental data based simulation study confirms the advantages of distance-type measure approach in both detection power and detection accuracy. Furthermore, we propose artificial censoring for the distance data so that distances larger than a given value are considered potential outliers. Our purpose is to simplify the pre-processing of DNA-seq data. Statistically, we consider a mixture of right censored geometric distributions to model the distance data. Additionally, to reduce the GC-content bias, we extend the mixture model to a mixture of generalized linear models (GLMs). The estimation of model can be achieved by the Newton-Raphson algorithm as well as the Expectation-Maximization (E-M) algorithm. We have conducted simulations to evaluate the performance of our approach. Based on the rank based inverse normal transformation of distance data, we can obtain the related z-values for a follow-up analysis. For an illustration, an application to the DNA-seq data from a pair of normal and tumor cell lines is presented with a change-point analysis of z-values to detect DNA copy number alterations.

Conclusion

Our distance-type measure approach is novel. It does not require either a fixed or a sliding window procedure for generating count-type data. Its advantages have been demonstrated by our simulation studies and its practical usefulness has been illustrated by an experimental data application.

     

Increase of myometrial activity correlated with variations in 17β-estradiol and progesterone uterine concentrations in mid-term pregnant rat: estrogen agonist effect of 4-hydroxytamoxifen

The objective of this investigation was to examine the effects of 4-hydroxytamoxifen on the uterine activity. For this, we evaluated the electrical activity of the myometrium, chronically, in conscious unrestrained rats at mid-pregnancy. We also examined the tissular progesterone and 17β-estradiol concentrations in the myometrium and uterus 6 hours after administration of 4-hydroxytamoxifen. Comparison of myometrial electrical activities recorded during the control period with those obtained during the two periods (6 and 24 hours) after administration of4-hydroxytamoxifen (80 μg.kg⁻¹, s.c.) showed an increase in simultaneity of uterine contractions (P < 0.01). Tissular steroid hormone measurement by radioimmunoassay shows a fall of progesterone in the myometrium (P < 0.001) and of 17β-estradiol in the uterus (P < 0.01), 6 hours after administration of 4-hydroxytamoxifen. In the myometrium, for 50% of animals, 17β-estradiol concentration decreased (P < 0.01) and for 50% of animals it increased (P < 0.05). The decrease in progesterone is significant in the myometrium and in the whole uterus (respectively P < 0.001 and P < 0.01), 24 hours after administration of 4-hydroxytamoxifen. The 17β-estradiol concentration significantly decreased for all animals in the myometrium (P < 0.01) and in the uterus (P < 0.01), after this time. It appears that variation in progesterone induces the activation of uterine motility and exerts an effect on some factors involved in the regulation of the rat myometrium at mid-pregnancy.     

Towards breast cancer rotational radiotherapy with synchrotron radiation

PurposeWe performed the first investigations, via measurements and Monte Carlo simulations on phantoms, of the feasibility of a new technique for synchrotron radiation rotational radiotherapy for breast cancer (SR³T).MethodsA Monte Carlo (MC) code based on Geant4 toolkit was developed in order to simulate the irradiation with the SR³T technique and to evaluate the skin sparing effect in terms of centre-to-periphery dose ratio at different energies in the range 60–175 keV. Preliminary measurements were performed at the Australian Synchrotron facility. Radial dose profiles in a 14-cm diameter polyethylene phantom were measured with a 100-mm pencil ionization chamber for different beam sizes and compared with the results of MC simulations. Finally, the dose painting feasibility was demonstrated with measurements with EBT3 radiochromic films in a phantom and collimating the SR beam at 1.5 cm in the horizontal direction.ResultsMC simulations showed that the SR³T technique assures a tumour-to-skin absorbed dose ratio from about 7:1 (at 60 keV photon energy) to about 10:1 (at 175 keV), sufficient for skin sparing during radiotherapy. The comparison between the results of MC simulations and measurements showed an agreement within 5%. Two off-centre foci were irradiated shifting the rotation centre in the horizontal direction.ConclusionsThe SR³T technique permits to obtain different dose distributions in the target with multiple rotations and can be guided via synchrotron radiation breast computed tomography imaging, in propagation based phase-contrast conditions. Use of contrast agents like iodinated solutions or gold nanoparticles for dose enhancement (DE-SR³T) is foreseen and will be investigated in future work.     

A mathematical model for the transmission of Schistosoma japonicum in consideration of seasonal water level fluctuations of Poyang Lake in Jiangxi,China

BackgroundPoyang Lake, the largest fresh water lake in China, is the major transmission site of Schistosoma japonicum in China. Epidemics of schistosomiasis japonica have threatened the health of residents and stunted social–economic development there.ObjectiveThis article aims at evaluating the effect of various control measures against schistosomiasis: selective mass treatment (ST), targeted mass treatment (TT), mass treatment for animal reservoirs (MT), and health education (HE), on reduction of the prevalence through simulations based on a mathematical model.MethodsWe proposed a mathematical model, which is a system of ordinary differential equations for the transmission of S. japonicum among humans, bovines, and snails. The model takes into account the seasonal variation of the water level of Poyang Lake that is caused by the backflow of the Yangtze River and inflow from five small rivers, which influences the transmission of S. japonicum. For the purpose of dealing with the age-specific prevalence and intensity of infection, the human population was classified into four age categories in the model. We carried out several simulations resulting from the execution of ST and TT for elementary school children (E Sch), and combinations of ST, MT, and HE.ResultsThe simulations indicated that all of the control measures only for humans had a trend of revival after interruption, and a combination of ST and MT has a significant effect on reducing human infection. Although TT and HE had a significant effect on the prevalence in the E Sch group, it had little effect on the overall human population.ConclusionThe simulations indicate that measures targeted to bovines such as chemotherapy besides humans will be vital to eliminate the transmission of S. japonicum in the Poyang Lake region. Moreover, it is desirable to improve health education for fishermen and herdsmen.     

Endopolyploidization and the interstitial invasion of the supergiant trophoblast cells of the field vole Microtus rossiaemeridionalis

The supergiant trophoblast cells characteristic of vole placenta prove to be highly invasive being found at the boundary of the decidualized endometrium and myometrium. Their size (100 μm and higher) suggests them to be highly polyploid, though their ploidy was not determined by now. We performed determination of the ploidy level of the supergiant trophoblast cells (SuGT) in order to verify whether the highly polyploid trophoblast cells are capable of deep intrauterine invasion. Anti-Cytokeratin trophoblast immunolabelling were performed to estimate the ways of the SuGT migration. DNA content measurement with help of image analysis was performed at the series of Feulgen-stained sections of the SuGT nuclei. The SuGT were observed to migrate through the endometrial stroma reaching myometrium. Most of the cells corresponded to 2048c-8192c; the maximum level was 16384c comparable to the salivary glands of Drosophila. The nuclei contained bundles of non-classic polytene chromosomes. At the final steps of differentiation when SuGT reach myometrium, the bundles of polytene chromosomes disintegrate into multiple separate endochromosomes. The supergiant trophoblast cells in Microtus rossiaemeridionalis represent an example of highly polyploid cells capable of deep intrauterine invasion.     

Predicting Liquid–Vapour Equilibria for Water Using an ab-initio Potential from Histogram Reweighting Monte Carlo Simulations

Abstract

The coexisting densities for an ab-initio model for water have been calculated using grand canonical Monte Carlo simulations with the histogram reweighting technique. Although good agreement with experimental data is found for the radial distribution function at room temperature, the predicted critical density and temperature are well below both the experimental value as well as predictions from semi-empirical potentials. Improvement in the repulsive part of the ab-initio potential is suggested as a way to obtain better agreement with experiment.     

Differential interactions of the antimicrobial peptide,RQ18, with phospholipids and cholesterol modulate its selectivity for microorganism membranes

BackgroundAntimicrobial peptides (AMPs) are molecules with potential application for the treatment of microorganism infections. We, herein, describe the structure, activity, and mechanism of action of RQ18, an α-helical AMP that displays antimicrobial activity against Gram-positive and Gram-negative bacteria, and yeasts from the Candida genus.MethodsA physicochemical-guided design assisted by computer tools was used to obtain our lead peptide candidate, named RQ18. This peptide was assayed against Gram-positive and Gram-negative bacteria, yeasts, and mammalian cells to determine its selectivity index. The secondary structure and the mechanism of action of RQ18 were investigated using circular dichroism, large unilamellar vesicles, and molecular dynamic simulations.ResultsRQ18 was not cytotoxic to human lung fibroblasts, peripheral blood mononuclear cells, red blood cells, or Vero cells at MIC values, exhibiting a high selectivity index. Circular dichroism analysis and molecular dynamic simulations revealed that RQ18 presents varying structural profiles in aqueous solution, TFE/water mixtures, SDS micelles, and lipid bilayers. The peptide was virtually unable to release carboxyfluorescein from large unilamellar vesicles composed of POPC/cholesterol, model that mimics the eukaryotic membrane, indicating that vesicles' net charges and the presence of cholesterol may be related with RQ18 selectivity for bacterial and fungal cell surfaces.ConclusionsRQ18 was characterized as a membrane-active peptide with dual antibacterial and antifungal activities, without compromising mammalian cells viability, thus reinforcing its therapeutic application.General significanceThese results provide further insight into the complex process of AMPs interaction with biological membranes, in special with systems that mimic prokaryotic and eukaryotic cell surfaces.     

Lipidomic analysis reveals prostanoid profiles in human term pregnant myometrium

Prostanoids modulate the activity of human pregnant myometrium and their functional role can be appreciated through characterisation of prostanoid receptors and tissue concentration of prostanoids. We have applied a lipidomic approach to elucidate the profile of prostanoids in human non-labouring and labouring myometrium. We have identified a total of nineteen prostanoids including prostacyclin, thromboxanes, prostaglandins and dihydro-prostaglandins. Prostacyclin was the predominant prostanoid in both non-labouring and labouring myometria, with PGD₂ and PGF_2α being the second most abundant. Although the total amount of prostanoids was increased in the labouring tissue, PGE₂ and 13,14-dihydro-15-keto-PGE₂ were the only prostanoids to increase significantly at early and late labour (p≤0.001). Our data suggest that PGF_2α plays an important role in parturition, whilst the increase in PGE₂ could occur to facilitate cervical dilation and relaxation of the lower myometrium during labour. Although the elevation in TXA₂ was less marked than expected, in terms of translation to function even a relatively small increase in the level of this potent spasmogen may have significant effects.     

Development of a deformable phantom for experimental verification of 4D Monte Carlo simulations in a deforming anatomy

PurposeTo verify the accuracy of 4D Monte Carlo (MC) simulations, using the 4DdefDOSXYZnrc user code, in a deforming anatomy. We developed a tissue-equivalent and reproducible deformable lung phantom and evaluated 4D simulations of delivered dose to the phantom by comparing calculations against measurements.MethodsA novel deformable phantom consisting of flexible foam, emulating lung tissue, inside a Lucite external body was constructed. A removable plug, containing an elastic tumor that can hold film and other dosimeters, was inserted in the phantom. Point dose and position measurements were performed inside and outside the tumor using RADPOS 4D dosimetry system. The phantom was irradiated on an Elekta Infinity linac in both stationary and moving states. The dose delivery was simulated using delivery log files and the phantom motion recorded with RADPOS.ResultsReproducibility of the phantom motion was determined to be within 1 mm. The phantom motion presented realistic features like hysteresis. MC calculations and measurements agreed within 2% at the center of tumor. Outside the tumor agreements were better than 5% which were within the positional/dose reading uncertainties at the measurement points. More than 94% of dose points from MC simulations agreed within 2%/2 mm compared to film measurements.ConclusionThe deformable lung phantom presented realistic and reproducible motion characteristics and its use for verification of 4D dose calculations was demonstrated. Our 4DMC method is capable of accurate calculations of the realistic dose delivered to a moving and deforming anatomy during static and dynamic beam delivery techniques.     

Characteristics of Bremsstrahlung emissions of 177Lu, 188Re,and 90Y for SPECT/CT quantification in radionuclide therapy

PurposeBeta particles emitted by radioisotopes used in targeted radionuclide therapies (TRT) create Bremsstrahlung (BRS) which may affect SPECT quantification when imaging these isotopes. The purpose of the current study was to investigate the characteristics of Bremsstrahlung produced in tissue by three β-emitting radioisotopes used in TRT.MethodsMonte Carlo simulations of ¹⁷⁷Lu, ¹⁸⁸Re, and ⁹⁰Y sources placed in water filled cylinders were performed. BRS yields, mean energies and energy spectra for (a) all photons generated in the decays, (b) photons that were not absorbed and leave the cylinder, and (c) photons detected by the camera were analyzed. Next, the results of simulations were compared with those from experiments performed on a clinical SPECT camera using same acquisition conditions and phantom configurations as in simulations.ResultsSimulations reproduced relatively well the shapes of the measured spectra, except for ⁹⁰Y which showed an overestimation in the low energy range. Detailed analysis of the results allowed us to suggest best collimators and imaging conditions for each of the investigated isotopes. Finally, our simulations confirmed that the BRS contribution to the energy spectra in quantitative imaging of ¹⁷⁷Lu and ¹⁸⁸Re could be ignored.ConclusionsFor ¹⁷⁷Lu and ¹⁸⁸Re, BRS contributes only marginally to the total spectra recorded by the camera. Our analysis shows that MELP and HE collimators are the best for imaging these two isotopes. For ⁹⁰Y, HE collimator should be used.     

Corticotropin-releasing hormone, its binding protein and receptors in human cervical tissue at preterm and term labor in comparison to non-pregnant state

Background  

Preterm birth is still the leading cause of neonatal morbidity and mortality. The level of corticotropin-releasing hormone (CRH) is known to be significantly elevated in the maternal plasma at preterm birth. Although, CRH, CRH-binding protein (CRH-BP), CRH-receptor 1 (CRH-R1) and CRH-R2 have been identified both at mRNA and protein level in human placenta, deciduas, fetal membranes, endometrium and myometrium, no corresponding information is yet available on cervix. Thus, the aim of this study was to compare the levels of the mRNA species coding for CRH, CRH-BP, CRH-R1 and CRH-R2 in human cervical tissue and myometrium at preterm and term labor and not in labor as well as in the non-pregnant state, and to localize the corresponding proteins employing immunohistochemical analysis.     

Synchronization by light of the circadian rhythm of motor activity in the crayfish

Abstract

We have studied the pattern for resetting the circadian rhythm in the spontaneous motor activity of the crayfish. Spontaneous motor activity was recorded continously at a constant temperature and under free running conditions in complete darkness. The effect of single light pulses applied at different circadian times, on the circadian rhythm of motor activity was measured in both transient stage and steady state. The results led us to construct a phase‐transition curve and phase‐response curve which were analyzed to obtain information about the oscillators which underlie the circadian rhythm of motor activity.     

Studies on the Pathogenic Potential and Life Cycle of Reniform Nematode on Broccoli

The significant reduction in the plant growth was observed at an initial inoculum level of 2 immature females of Rotylenchulus reniformis/g soil and hence this inoculum level was considered as the minimum damaging threshold level for broccoli. The population of reniform nematode increased with the increasing levels of inoculum. Though, the maximum nematode population was recorded at the highest level of inoculum, the rate of reproduction of nematode was found to be highest at the lowest level of initial inoculum. Symptoms like chlorosis, stunted growth, shedding of leaves, early sprouting of inflorescence and sparsely developed roots were found during the experimental studies. Rotylenchulus reniformis required 30 days to complete the life cycle on broccoli.     

Counting birds on farmland habitats in winter

Capsule Perimeter counts underestimate the number of birds using agricultural fields.

Aims To determine the degree to which farmland birds may be undercounted on field surveys and the factors influencing this.

Methods In a study of 96 fields, birds in the field were counted during a walk of the perimeter. Afterwards transects were walked across the field to determine the number of birds missed. Additionally in a national survey we looked at the birds seen in field transects expressed as a proportion of the total seen in the transect and on perimeter counts.

Results To obtain an accurate count of birds on a field requires the use of the whole-area search methodology especially for species such as Grey Partridge Perdix perdix, Snipe Gallinago gallinago, Skylark Alauda arvensis and Meadow Pipit Anthus pratensis. However, for a large number of species, including thrushes, flocking finches and buntings, over 90% of individuals can be recorded using the much less time-consuming perimeter count method.

Conclusions Perimeter counts are likely to be reliable for most species but special efforts may be required for a few cryptic species.     

Regulation of cGMP-induced relaxation and cGMP-dependent protein kinase in rat myometrium during pregnancy

Increases inguanosine 3',5'-cyclic monophosphate (cGMP) induced bynitric oxide (NO), nitrovasodilators, and atrial peptides correlatewith relaxation of vascular smooth muscle. Relaxation of myometrialsmooth muscle by increases in cGMP, however, has required unusuallyhigh concentrations of the cyclic nucleotide. We tested the hypothesisthat the sensitivity of myometrium to relaxation by cGMP is increasedduring pregnancy. Aortic smooth muscle was more sensitive to relaxationby cGMP than myometrial tissues, and, contrary to our hypothesis,myometrium from pregnant rats was least sensitive. Although levels ofcGMP were elevated after treatment with the NO donor,S-nitroso-N-acetylpenicillamine, relaxation of myometrial tissues obtained from pregnant rats occurred only at extraordinarily high concentrations. The levels ofcGMP-dependent protein kinase (PKG) were significantly decreased inmyometrium from pregnant rats compared with myometrium from nonpregnantcycling animals or aortic smooth muscle. Administration of estradiol to ovariectomized rats increased myometrial PKG expression, andprogesterone antagonized this response. We conclude that1) myometrial tissues from pregnantrats are not sensitive to relaxation by cGMP and 2) this insensitivity to cGMP isaccompanied by progesterone-mediated decreases in the level of PKGexpression.

     

URBAN NOISE PREDICTS SONG FREQUENCY IN NORTHERN CARDINALS AND AMERICAN ROBINS

ABSTRACT

We examined the extent to which acoustic noise in urban environments influences song characteristics and singing behaviour of Northern Cardinals Cardinalis cardinalis and American Robins Turdus migratorius. We predicted that, in response to loud noise, birds would improve signal transmission by (1) increasing singing rate and (2) adjusting song characteristics such as pitch and length. From May—July 2006, 42 cardinals and 53 robins were recorded in forests located within four acoustic environments in central Ohio: rural, residential, commercial, and highway. Following each recording, we measured ambient noise level and recorded information describing location, weather, habitat, and conspecific presence within 75 m. As predicted, frequency range was positively correlated with noise level for both species, but neither song length nor rate was related to noise level for either species. These data support the idea that anthropogenic noise influences avian singing behaviour and acts as a selective force in urban areas.     

Monte Carlo studies in Gold Nanoparticles enhanced radiotherapy: The impact of modelled parameters in dose enhancement

PurposeOver the last decades, Gold Nanoparticles (AuNPs) have been presented as an innovative approach in radiotherapy (RT) enhancement. Several studies have proven that the irradiation of tumors containing AuNPs could lead to more effective tumor control than irradiation alone. Studies with low kV photons and AuNPs conclude in encouraging results regarding the level of radioenhancement. However, experimental and theoretical studies with MV photons report controversial findings concerning the correlation between dose enhancement effect and tumor cell killing. The great variation in the experimental protocols and simulations complicates the comparison of their outcomes and depicts the need for limiting the variety of investigated parameters. Our purpose is to point out a possible direction for building realistic Monte Carlo (MC) models that could end up with promising results in MV photons RT enhancement.MethodsWe explored published in silico studies concerning AuNPs enhanced RT from 2010 to 2019. In this review, we discuss the different AuNPs and MV photon beams characteristics that have been reported and their effect in dose enhancement.ResultsAuNPs size, concentration, type of distribution along with photon beams energy and the presence of flattening filter in linear accelerators seem to be the major parameters that determine AuNPs radioenhancement in silico.ConclusionsPrior to AuNPs clinical translation in photon radiotherapy, in silico studies should emphasize on nanodosimetry and track structure codes than condensed history ones. Toxicity estimation and biological aspects should be implemented in MC simulations so as to achieve accurate and realistic modelling of AuNPs driven RT.