Cyclic 3',5'-adenosine monophosphate-dependent kinase and phosphoproteins in human amnion

3',5'-Cyclic adenosine monophosphate (cAMP) modulates prostaglandin production in human amnion membranes. The major effects of cAMP are presumably mediated through the phosphorylation of specific regulatory phosphoproteins following cAMP activation of cAMP-dependent protein kinase. Cyclic AMP-dependent protein kinase and phosphoproteins have not previously been characterized in human amnion. Total homogenates, cytosol, and membrane fractions from human amnion were examined for [3H]cAMP binding activity and cAMP-dependent kinase activity. cAMP-dependent kinase activity was barely detectable in crude amnion fractions. Cytosol was therefore partially purified by DEAE column chromatography for further examination. Two peaks of coincident [3H]cAMP binding and cAMP-dependent kinase activity were demonstrated at 70 and 140 mM NaCl, characteristic of the Type I and Type II cAMP-dependent protein kinase isozymes. [3H]cAMP binding to the material from both peak fractions was saturable and reversible. Scatchard analysis of [3H]cAMP binding to the peak fractions was linear for peak I and curvilinear for peak II. Assuming a one-site model, [3H]cAMP binding to the Type I isozyme showed a KD = 4.17 x 10(-8) M and Bmax = 73 pmole/mg protein; using a two-site model, [3H]cAMP binding to the high-affinity site for the Type II isozyme had a KD = 3.94 x 10(-8) M and Bmax = 6.3 pmole/mg protein. Other cyclic nucleotides competed for these [3H]cAMP binding sites with a potency order of cAMP much greater than cGMP greater than (BU)2cAMP.cAMP caused a dose-dependent increase in cAMP-dependent kinase activity in the peak fractions; half-maximal activation was observed with 5.0 x 10(-8) M cAMP. The ability of cAMP to increase phosphorylation of endogenous proteins in both crude amnion cytosol and cytosol from cultures of amnion epithelial cells was assessed using [32P]ATP, SDS-polyacrylamide gel electrophoresis and autoradiography. cAMP stimulated 32P incorporation into three proteins having Mr = 80,000, 54,000, and 43,000 (P less than .01). Half-maximal 32P incorporation into these proteins occurred at 1.0 x 10(-7) M cAMP. cAMP-dependent kinase is present in human amnion; specific cAMP-enhanced phosphoproteins are also present. Hormones elevating cAMP levels in amnion may exert their effects by activating cAMP-dependent kinase and phosphorylating these phosphoproteins.     

Einschlußkörper in den Epidermiszellen vonChlorophytum comosum

Zusammenfassung Iu den Epidermiszelien vonChlorophytum cornosum (und auchChlorophytum elatum) kommen in den Vakuolen Kristalldrusen vor. deren chemische Natur noch nicht eindeutig festgestellt werden konnte. Da neben den Drusen auch noch lebhaft bewegliche Cytoplasmaballen. die als x-Bodies angesehen werden und auch fibrilläre Eiweißspindeln beobachtet wurden, wird angenommen, daß die erwähnten Kristalldrusen ebenfalls Stoffwechselprodukte virusinfizierter Zellen sind. Auch polsterartige Kallosebildungen an den Zellwänden dieser Zellen sowie die Übertragbarkeit durch Einreihen von Preßsaft verstärken die Vermutung, daß alle diese Inhaltskörper als Folge einer Virusinfektion in den Zellen entstanden sind.Dem Andenken meines unvergeßlichen Lehrers Professor Friedl Weber gewidmet.     

Increase in β-1,4-Galactosyltransferase Activity During PC12 Cell Differentiation Induced by Forskolin and 2-Chloroadenosine

Galactosyltransferase (GALTase) activity was measured in differentiating PC12 cells induced by either forskolin or 2-chloroadenosine. The specific activity of GALTase in whole cells and isolated Golgi membranes increased as early as 3 h after initiating treatment with 2-chloroadenosine, and maximal activity was reached at approximately 12 h. In two mutant PC12 cell lines deficient in protein kinase A, both forskolin and 2-chloroadenosine failed to increase GALTase activity. The adenosine A2 receptor antagonist, xanthine amine congener, prevented 2-chloroadenosine stimulation of GALTase, demonstrating that this adenosine derivative was mediating its effect via the A2 receptor. These data suggest that GALTase activity during PC12 cell differentiation is regulated by cyclic AMP (cAMP)- and protein kinase A-dependent processes. In support of the role of cAMP in regulating GALTase activity were studies with murine PC carcinoma cells demonstrating that the greatest stimulation of GALTase activity occurred with cells treated with both retinoic acid and dibutyryl cAMP.     

Complex Patterns of Chromosome 11 Aberrations in Myeloid Malignancies Target CBL,MLL, DDB1 and LMO2

Exome sequencing of primary tumors identifies complex somatic mutation patterns. Assignment of relevance of individual somatic mutations is difficult and poses the next challenge for interpretation of next generation sequencing data. Here we present an approach how exome sequencing in combination with SNP microarray data may identify targets of chromosomal aberrations in myeloid malignancies. The rationale of this approach is that hotspots of chromosomal aberrations might also harbor point mutations in the target genes of deletions, gains or uniparental disomies (UPDs). Chromosome 11 is a frequent target of lesions in myeloid malignancies. Therefore, we studied chromosome 11 in a total of 813 samples from 773 individual patients with different myeloid malignancies by SNP microarrays and complemented the data with exome sequencing in selected cases exhibiting chromosome 11 defects. We found gains, losses and UPDs of chromosome 11 in 52 of the 813 samples (6.4%). Chromosome 11q UPDs frequently associated with mutations of CBL. In one patient the 11qUPD amplified somatic mutations in both CBL and the DNA repair gene DDB1. A duplication within MLL exon 3 was detected in another patient with 11qUPD. We identified several common deleted regions (CDR) on chromosome 11. One of the CDRs associated with de novo acute myeloid leukemia (P=0.013). One patient with a deletion at the LMO2 locus harbored an additional point mutation on the other allele indicating that LMO2 might be a tumor suppressor frequently targeted by 11p deletions. Our chromosome-centered analysis indicates that chromosome 11 contains a number of tumor suppressor genes and that the role of this chromosome in myeloid malignancies is more complex than previously recognized.     

Improving Education in Medical Statistics: Implementing a Blended Learning Model in the Existing Curriculum

Background

Although recent studies report on the benefits of blended learning in improving medical student education, there is still no empirical evidence on the relative effectiveness of blended over traditional learning approaches in medical statistics. We implemented blended along with on-site (i.e. face-to-face) learning to further assess the potential value of web-based learning in medical statistics.

Methods

This was a prospective study conducted with third year medical undergraduate students attending the Faculty of Medicine, University of Belgrade, who passed (440 of 545) the final exam of the obligatory introductory statistics course during 2013–14. Student statistics achievements were stratified based on the two methods of education delivery: blended learning and on-site learning. Blended learning included a combination of face-to-face and distance learning methodologies integrated into a single course.

Results

Mean exam scores for the blended learning student group were higher than for the on-site student group for both final statistics score (89.36±6.60 vs. 86.06±8.48; p = 0.001) and knowledge test score (7.88±1.30 vs. 7.51±1.36; p = 0.023) with a medium effect size. There were no differences in sex or study duration between the groups. Current grade point average (GPA) was higher in the blended group. In a multivariable regression model, current GPA and knowledge test scores were associated with the final statistics score after adjusting for study duration and learning modality (p<0.001).

Conclusion

This study provides empirical evidence to support educator decisions to implement different learning environments for teaching medical statistics to undergraduate medical students. Blended and on-site training formats led to similar knowledge acquisition; however, students with higher GPA preferred the technology assisted learning format. Implementation of blended learning approaches can be considered an attractive, cost-effective, and efficient alternative to traditional classroom training in medical statistics.     

Support for Kurdish language rights in Turkey: the roles of ethnic group,group identifications,contact, and intergroup perceptions

The question of Kurdish language rights has been a central issue in the Turkish–Kurdish conflict. The current study examined endorsement of Kurdish language rights in relation to intergroup factors (i.e. group identifications, cross-group friendships, perceived discrimination, and perceived out-group beliefs about state unity) among self-identified Turkish and Kurdish participants. The results indicate that Turks were much less in favour of these rights than the Kurds. In addition, for the Turks, higher national and ethnic identification were associated with lower support for Kurdish language rights, while cross-group friendship, perceived discrimination of Kurds and the belief that Kurds endorse national unity were associated with more support for rights. For the Kurdish participants, stronger national identification seems to undermine the mobilizing meaning that Kurdish group identification has for language rights support. Furthermore, friendship with Turks can undermine the support for rights because it strengthens national identification and reduces ethnic identification.     

A computer-based simulation of childbirth using the partial Dirichlet–Neumann contact method with total Lagrangian explicit dynamics on the GPU

During physiological or ‘natural’ childbirth, the fetal head follows a distinct motion pattern—often referred to as the cardinal movements or ‘mechanisms’ of childbirth—due to the biomechanical interaction between the fetus and maternal pelvic anatomy. The research presented in this paper introduces a virtual reality-based simulation of physiological childbirth. The underpinning science is based on two numerical algorithms including the total Lagrangian explicit dynamics method to calculate soft tissue deformation and the partial Dirichlet–Neumann contact method to calculate the mechanical contact interaction between the fetal head and maternal pelvic anatomy. The paper describes the underlying mathematics and algorithms of the solution and their combination into a computer-based implementation. The experimental section covers first a number of validation experiments on simple contact mechanical problems which is followed by the main experiment of running a virtual reality childbirth. Realistic mesh models of the fetus, bony pelvis and pelvic floor muscles were subjected to the intra-uterine expulsion forces which aim to propel the virtual fetus through the virtual birth canal. Following a series of simulations, taking variations in the shape and size of the geometric models into account, we consistently observed the cardinal movements in the simulator just as they happen in physiological childbirth. The results confirm the potential of the simulator as a predictive tool for problematic childbirths subject to patient-specific adaptations.

     

Steroid structural requirements for interaction of ostreolysin, a lipid-raft binding cytolysin, with lipid monolayers and bilayers

Ostreolysin, a cytolytic protein from the edible oyster mushroom (Pleurotus ostreatus), recognizes and binds specifically to membrane domains enriched in cholesterol and sphingomyelin (or saturated phosphatidylcholine). These events, leading to permeabilization of the membrane, suggest that a cholesterol-rich liquid-ordered membrane phase, which is characteristic of lipid rafts, could be its possible binding site. In this work, we present effects of ostreolysin on membranes containing various steroids. Binding and membrane permeabilizing activity of ostreolysin was studied using lipid mono- and bilayers composed of sphingomyelin combined, in a 1/1 molar ratio, with natural and synthetic steroids (cholesterol, ergosterol, beta-sitosterol, stigmasterol, lanosterol, 7-dehydrocholesterol, cholesteryl acetate, and 5-cholesten-3-one). Binding to membranes and lytic activity of the protein are both shown to be dependent on the intact sterol 3beta-OH group, and are decreased by introducing additional double bonds and methylation of the steroid skeleton or C17-isooctyl chain. The activity of ostreolysin mainly correlates with the ability of the steroids to promote formation of liquid-ordered membrane domains, and is the highest with cholesterol-containing membranes. Furthermore, increasing the cholesterol concentration enhanced ostreolysin binding in a highly cooperative manner, suggesting that the membrane lateral distribution and accessibility of the sterols are crucial for the activity of this new member of cholesterol-dependent cytolysins.     

Diversity of halophilic archaea in the crystallizers of an Adriatic solar saltern

Haloarchaeal diversity in the crystallizers of Adriatic Secovlje salterns was investigated using gene fragments encoding 16S rRNA and bacteriorhodopsin as molecular markers. Screening of 180 clones from five gene libraries constructed for each gene targeted revealed 15 different 16S rRNA and 10 different bacteriorhodopsin phylotypes, indicating higher haloarchaeal diversity than previously reported in such hypersaline environments. Furthermore, results of rarefaction analysis indicated that analysis of an increasing number of clones would have revealed additional diversity. Finally, most sequences from the crystallizers grouped within the Halorubrum branch, whereas square-shaped 'Haloquadratum' relatives, repeatedly reported to dominate crystallizer communities, were rare. Presence of such special and diverse haloarchaeal community could be attributed to the Secovlje salterns rare continuous short-cycling salt production mechanism.