Review: Genetic manipulation of the rodent placenta

The principal role of the placenta is the maintenance of pregnancy and promotion of fetal growth and viability. The use of transgenic rodents has greatly enhanced our understanding of placental development and function. However, embryonic lethality is often a confounding variable in determining whether a genetic modification adversely affected placental development. In these cases, it is beneficial to specifically manipulate the placental genome. The purpose of this review is to summarize available methodologies for specific genetic modification of the rodent placenta. By restricting genetic alterations to the trophoblast lineage, it is possible to gain a deeper understanding of placental development that perhaps will lead to gene-targeted therapies to rescue irregular placentation in transgenic animals or in women at high-risk for placenta-associated pregnancy complications

Obturations en amalgame et modifications des lymphocytes T

Dental amalgam and nickel alloys have been considered quite safe. Previous authors reported the effect of dental amalgam and nickel alloys on human T-lymphocytes modifications after amalgam dental fillings, into dose-dependence of any modifications and into possible temporary.Eight patients were subjected to dental care with amalgam dental fillings. Drawings of blood were executed at start, fifteen days after late fillings and two months later.The results about modifications of T-lymphocytes were not univocal. We believe, at now, that temporary modifications of the immunity seem to be related to a cytotoxic mechanism.Les auteurs ont étudié les modifications systémiques des lymphocytes T (T3) et des sous-populations T4 et T8 après la pose d’obturations en amalgame. Les résultats ne sont pas univoques et leur interprétation n’est pas facile.On pense que l’amalgame dentaire pourrait provoquer une modification transitoire et temporaire des défenses immunitaires par un mécanisme de cytotoxicité

Rat placentation: An experimental model for investigating the hemochorial maternal-fetal interface

The rat possesses hemochorial placentation with deep intrauterine trophoblast cell invasion and trophoblast-directed uterine spiral artery remodeling; features shared with human placentation. Recognition of these similarities spurred the establishment of in vitro and in vivo research methods using the rat as an animal model to address mechanistic questions regarding development of the hemochorial placenta. The purpose of this review is to provide the requisite background to help move the rat to the forefront in placentation research. © 2012 Elsevier Ltd. All rights reserved

Microbiological quality of some common dairy beverages available in Dhaka University campus of Bangladesh

Dairy beverages are nutritious and also highly susceptible to bacterial contamination posing a threat to human health. In recent years, production and consumption of dairy beverages are rapidly increasing in Bangladesh; however, the presence of bacteria including human pathogens in commonly consumed dairy beverages has not been evaluated before. Here, we focused on microbiological quality of some dairy beverages available in Dhaka University campus. We examined 25 samples from five different items locally named as Lassi, Labang, Borhani, Pistachio nut sherbet, and Strawberry milkshake. Non-selective medium PCA and different selective agar media such as MacConkey, SS, EMB, and TCBS, and Cooked Meat were used for isolation. Antibiotic resistance was assessed by disk diffusion method against Ampicillin, Colistin, Ciprofloxacin, Levofloxacin, Ceftriaxon, and Gentamycin. In PCA medium, Labang and Strawberry milkshake, respectively, showed the highest (3.6 × 107 CFU/mL) and the lowest (1.76 × 103 CFU/mL) bacterial count. In MacConkey and EMB media, the highest bacterial growths were, respectively, shown by Pistachio nut sherbet (1.22 × 104 CFU/mL) and Lassi (2.96 × 103 CFU/mL) whereas no growth was observed for Borhani. Strawberry milkshake was found with the highest bacterial prevalence such as E. coli, Klebsiella, Proteus, Pseudomonas Bacillus, Micrococcus, and Streptococcus whereas Borhani and Labang contained the lowest variety of bacteria. Isolates such as Shigella, Aeromonas, Micrococcus, Bacillus, Streptococcus, and Proteus were multi-drug resistant to Ampicillin and Colistin. Findings indicated that examined samples contained health risk factor. Findings may help relevant stakeholders to consider food safety issues of dairy beverages during processing, marketing, and consumption

Adaptive mechanisms controlling uterine spiral artery remodeling during the establishment of pregnancy

Implantation of the embryo into the uterus triggers the initiation of hemochorial placentation. The hemochorial placenta facilitates the acquisition of maternal resources required for embryo/fetal growth. Uterine spiral arteries form the nutrient supply line for the placenta and fetus. This vascular conduit undergoes gestation stage-specific remodeling directed by maternal natural killer cells and embryo-derived invasive trophoblast lineages. The placentation site, including remodeling of the uterine spiral arteries, is shaped by environmental challenges. In this review, we discuss the cellular participants controlling pregnancy-dependent uterine spiral artery remodeling and mechanisms responsible for their development and function. © 2014 UBC Press

Dynamics of stick-slip in peeling of an adhesive tape

We investigate the dynamics of peeling of an adhesive tape subjected to a constant pull speed. We derive the equations of motion for the angular speed of the roller tape, the peel angle and the pull force used in earlier investigations using a Lagrangian. Due to the constraint between the pull force, peel angle and the peel force, it falls into the category of differential-algebraic equations requiring an appropriate algorithm for its numerical solution. Using such a scheme, we show that stick-slip jumps emerge in a purely dynamical manner. Our detailed numerical study shows that these set of equations exhibit rich dynamics hitherto not reported. In particular, our analysis shows that inertia has considerable influence on the nature of the dynamics. Following studies in the Portevin-Le Chatelier effect, we suggest a phenomenological peel force function which includes the influence of the pull speed. This reproduces the decreasing nature of the rupture force with the pull speed observed in experiments. This rich dynamics is made transparent by using a set of approximations valid in different regimes of the parameter space. The approximate solutions capture major features of the exact numerical solutions and also produce reasonably accurate values for the various quantities of interest.Comment: 12 pages, 9 figures. Minor modifications as suggested by refere

Goat Genomic Resources: The Search for Genes Associated with Its Economic Traits

Goat plays a crucial role in human livelihoods, being a major source of meat, milk, fiber, and hides, particularly under adverse climatic conditions. The goat genomics related to the candidate gene approach is now being used to recognize molecular mechanisms that have different expressions of growth, reproductive, milk, wool, and disease resistance. The appropriate literature on this topic has been reviewed in this article. Several genetic characterization attempts of different goats have reported the existence of genotypic and morphological variations between different goat populations. As a result, different whole-genome sequences along with annotated gene sequences, gene function, and other genomic information of different goats are available in different databases. The main objective of this review is to search the genes associated with economic traits in goats. More than 271 candidate genes have been discovered in goats. Candidate genes influence the physiological pathway, metabolism, and expression of phenotypes. These genes have different functions on economically important traits. Some genes have pleiotropic effect for expression of phenotypic traits. Hence, recognizing candidate genes and their mutations that cause variations in gene expression and phenotype of an economic trait can help breeders look for genetic markers for specific economic traits. The availability of reference whole-genome assembly of goats, annotated genes, and transcriptomics makes comparative genomics a useful tool for systemic genetic upgradation. Identification and characterization of trait-associated sequence variations and gene will provide powerful means to give positive influences for future goat breeding program