Postnatal maturation in nitric oxide-induced pulmonary artery relaxation involving cyclooxygenase-1 activity

The maturation in the vasodilator response to nitric oxide (NO) in isolated intrapulmonary arteries was analyzed in newborns and 15- to 20-day-old piglets. The vasodilator responses to NO gas but not to the NO donor sodium nitroprusside increased with age. The inhibitory effects of the superoxide dismutase inhibitor diethyldithiocarbamate and xanthine oxidase plus hypoxanthine and the potentiation induced by superoxide dismutase and MnCl(2) of NO-induced vasodilatation were similar in the two age groups. Diphenyleneiodonium (NADPH oxidase inhibitor) potentiated the response to NO, and this effect was more pronounced in the older animals. The nonselective cyclooxygenase inhibitors indomethacin and meclofenamate and the preferential cyclooxygenase-1 inhibitor aspirin augmented NO-induced relaxation specifically in newborns, whereas the selective cycloxygenase-2 inhibitor NS-398 had no effect. The expressions of alpha-actin, cycloxygenase-1, and cycloxygenase-2 proteins were similar, whereas Cu,Zn-superoxide dismutase decreased with age. Therefore, the present data suggest that the maturational increase in the vasodilatation of NO in the pulmonary arteries during the first days of extrauterine life involves a cycloxygenase-dependent inhibition of neonatal NO activity.     

Activity of prostaglandin E, F, A and B on sphincter, dilator and ciliary muscle preparations of the cat eye

Both sphincter and dilator muscle preparations of the cat iris contract to prostaglandins; F_2α and E₂ are the most potent and A₁ and B₁ the least. Ciliary muscle strips relax to PG's provided that the strips are precontracted. E₁, E₂ and often F_2α are more potent relaxants than the remaining PG's. The effects of PG's are not altered by α or β blockade nor by atropine; however, propranolol blocks the PG induced relaxation of the ciliary muscle. The effects of PG's on the sphincter are antagonized by catecholamines; but the latter act synergistically in contracting the dilator and in relaxing the ciliary muscle. Indomethacin markedly potentiates the effects of PG's on all three muscle preparations.     

The Impact of the West Africa Ebola Outbreak on Obstetric Health Care in Sierra Leone

Background

As Sierra Leone celebrates the end of the Ebola Virus Disease (EVD) outbreak, we can begin to fully grasp its impact on already weak health systems. The EVD outbreak in West Africa forced many hospitals to close down or reduce their activity, either to prevent nosocomial transmission or because of staff shortages. The aim of this study is to assess the potential impact of EVD on nationwide access to obstetric care in Sierra Leone.

Methods and Findings

Community health officers collected weekly data between January 2014—May 2015 on in-hospital deliveries and caesarean sections (C-sections) from all open facilities (public, private for-profit and private non-profit sectors) offering emergency obstetrics in Sierra Leone. This was compared to official data of EVD cases per district. Logistic and Poisson regression analyses were used to compute risk and rate estimates. Nationwide, the number of in-hospital deliveries and C-sections decreased by over 20% during the EVD outbreak. The decline occurred early on in the EVD outbreak and was mainly attributable to the closing of private not-for-profit hospitals rather than government facilities. Due to difficulties in collecting data in the midst of an epidemic, limitations of this study include some missing data points.

Conclusions

Both the number of in-hospital deliveries and C-sections substantially declined shortly after the onset of the EVD outbreak. Since access to emergency obstetric care, like C-sections, is associated with decreased maternal mortality, many women are likely to have died due to the reduced access to appropriate care during childbirth. Future research on indirect health effects of health system breakdown should ideally be nationwide and continue also into the recovery phase. It is also important to understand the mechanisms behind the deterioration so that important health services can be reestablished.     

Characterization of Bacterial Communities in Selected Smokeless Tobacco Products Using 16S rDNA Analysis

The bacterial communities present in smokeless tobacco (ST) products have not previously reported. In this study, we used Next Generation Sequencing to study the bacteria present in U.S.-made dry snuff, moist snuff and Sudanese toombak. Sample diversity and taxonomic abundances were investigated in these products. A total of 33 bacterial families from four phyla, Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes, were identified. U.S.-produced dry snuff products contained a diverse distribution of all four phyla. Moist snuff products were dominated by Firmicutes. Toombak samples contained mainly Actinobacteria and Firmicutes (Aerococcaceae, Enterococcaceae, and Staphylococcaceae). The program PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) was used to impute the prevalence of genes encoding selected bacterial toxins, antibiotic resistance genes and other pro-inflammatory molecules. PICRUSt also predicted the presence of specific nitrate reductase genes, whose products can contribute to the formation of carcinogenic nitrosamines. Characterization of microbial community abundances and their associated genomes gives us an indication of the presence or absence of pathways of interest and can be used as a foundation for further investigation into the unique microbiological and chemical environments of smokeless tobacco products.     

Differential regulation of the postsynaptic clustering of γ-aminobutyric acid type A (GABAA) receptors by collybistin isoforms

Collybistin promotes submembrane clustering of gephyrin and is essential for the postsynaptic localization of gephyrin and γ-aminobutyric acid type A (GABA(A)) receptors at GABAergic synapses in hippocampus and amygdala. Four collybistin isoforms are expressed in brain neurons; CB2 and CB3 differ in the C terminus and occur with and without the Src homology 3 (SH3) domain. We have found that in transfected hippocampal neurons, all collybistin isoforms (CB2(SH3+), CB2(SH3-), CB3(SH3+), and CB3(SH3-)) target to and concentrate at GABAergic postsynapses. Moreover, in non-transfected neurons, collybistin concentrates at GABAergic synapses. Hippocampal neurons co-transfected with CB2(SH3-) and gephyrin developed very large postsynaptic gephyrin and GABA(A) receptor clusters (superclusters). This effect was accompanied by a significant increase in the amplitude of miniature inhibitory postsynaptic currents. Co-transfection with CB2(SH3+) and gephyrin induced the formation of many (supernumerary) non-synaptic clusters. Transfection with gephyrin alone did not affect cluster number or size, but gephyrin potentiated the clustering effect of CB2(SH3-) or CB2(SH3+). Co-transfection with CB2(SH3-) or CB2(SH3+) and gephyrin did not affect the density of presynaptic GABAergic terminals contacting the transfected cells, indicating that collybistin is not synaptogenic. Nevertheless, the synaptic superclusters induced by CB2(SH3-) and gephyrin were accompanied by enlarged presynaptic GABAergic terminals. The enhanced clustering of gephyrin and GABA(A) receptors induced by collybistin isoforms was not accompanied by enhanced clustering of neuroligin 2. Moreover, during the development of GABAergic synapses, the clustering of gephyrin and GABA(A) receptors preceded the clustering of neuroligin 2. We propose a model in which the SH3- isoforms play a major role in the postsynaptic accumulation of GABA(A) receptors and in GABAergic synaptic strength.     

The multicompartmental p32/gClqR as a new target for antibody-based tumor targeting strategies

Tumor-associated cell surface antigens and tumor-associated vascular markers have been used as a target for cancer intervention strategies. However, both types of targets have limitations due to accessibility, low and/or heterogeneous expression, and presence of tumor-associated serum antigen. It has been previously reported that a mitochondrial/cell surface protein, p32/gC1qR, is the receptor for a tumor-homing peptide, LyP-1, which specifically recognizes an epitope in tumor cells, tumor lymphatics, and tumor-associated macrophages/myeloid cells. Using antibody phage technology, we have generated an anti-p32 human monoclonal antibody (2.15). The 2.15 antibody, expressed in single-chain fragment variable and in trimerbody format, was then characterized in vivo using mice grafted subcutaneously with MDA-MB-231 human breast cancers cells, revealing a highly selective tumor uptake. The intratumoral distribution of the antibody was consistent with the expression pattern of p32 in the surface of some clusters of cells. These results demonstrate the potential of p32 for antibody-based tumor targeting strategies and the utility of the 2.15 antibody as targeting moiety for the selective delivery of imaging and therapeutic agents to tumors.     

Conformational Dynamics and Structural Plasticity Play Critical Roles in the Ubiquitin Recognition of a UIM Domain

Ubiquitin-interacting motifs (UIMs) are an important class of protein domains that interact with ubiquitin or ubiquitin-like proteins. These approximately 20-residue-long domains are found in a variety of ubiquitin receptor proteins and serve as recognition modules towards intracellular targets, which may be individual ubiquitin subunits or polyubiquitin chains attached to a variety of proteins. Previous structural studies of interactions between UIMs and ubiquitin have shown that UIMs adopt an extended structure of a single α-helix, containing a hydrophobic surface with a conserved sequence pattern that interacts with key hydrophobic residues on ubiquitin. In light of this large body of structural studies, details regarding the presence and the roles of structural dynamics and plasticity are surprisingly lacking. In order to better understand the structural basis of ubiquitin-UIM recognition, we have characterized changes in the structure and dynamics of ubiquitin upon binding of a UIM domain from the yeast Vps27 protein. The solution structure of a ubiquitin-UIM fusion protein designed to study these interactions is reported here and found to consist of a well-defined ubiquitin core and a bipartite UIM helix. Moreover, we have studied the plasticity of the docking interface, as well as global changes in ubiquitin due to UIM binding at the picoseconds-to-nanoseconds and microseconds-to-milliseconds protein motions by nuclear magnetic resonance relaxation. Changes in generalized-order parameters of amide groups show a distinct trend towards increased structural rigidity at the UIM-ubiquitin interface relative to values determined in unbound ubiquitin. Analysis of ¹⁵N Carr-Purcell-Meiboom-Gill relaxation dispersion measurements suggests the presence of two types of motions: one directly related to the UIM-binding interface and the other induced to distal parts of the protein. This study demonstrates a case where localized interactions among protein domains have global effects on protein motions at timescales ranging from picoseconds to milliseconds.     

Genetic and epigenetic relationship in rye, Secale cereale L., somaclonal variation within somatic embryo-derived plants

In vitro regenerated plants of rye, Secale cereale L., Ailés and Merced cultivars, were studied to verify if genetic and/or epigenetic changes were promoted by in vitro conditions. Inter-simple sequence repeat (ISSR) fingerprints on HpaII/MspI-digested and uncut DNA were generated. DNA digested with methylation-sensitive isoschizomers revealed epigenetic modifications, while modification of ISSR patterns obtained with undigested DNA indicated genetic changes. With this technique, it was possible to study both genetic and/or epigenetic changes within the same DNA sequences. The frequency of plants with at least one variation was high: 73% and 30% of rye plants showed at least one genetic change, and 50% and 73% carried at least one methylation change, in the Ailés and Merced cultivars, respectively. Further analyses revealed that a considerable number of variable markers showed both types of modifications, indicative of both genetic and epigenetic changes. Moreover, genetic variation was related to the presence of the CCGG target in the analyzed bands. These results indicate the possible existence of a common mechanism connecting both types of variation.