A case of congenital factor XIII deficiency

The case of a 53 years old woman was described in whom a congenital factor XIII deficiency was suspected because of deforming scars and hemorrhagic diathesis. A thromboelastographic declination of elasticity as well as decreased factor XIII level up to 5% of normal range were only found in all hemostatic examinations. In 2 children factor XIII decreased to half of its normal level, whereas in the youngest daughter that level was 25%. Sporadically the girl had mild diathesis. No changes in thromboelastograms were observed in members of the patient's family. The platelet function was unchanged in all examined cases.     

Wrinkling instabilities for biologically relevant fiber-reinforced composite materials with a case study of Neo-Hookean/Ogden–Gasser–Holzapfel bilayer

Biomechanics and Modeling in Mechanobiology - Wrinkling is a ubiquitous surface phenomenon in many biological tissues and is believed to play an important role in arterial health. As arteries are...     

Oxidative stress in small-for-gestational age (SGA) term newborns and their mothers

This study used malondialdehyde (MDA) determination by HPLC and enzymatic assays for total serum peroxides and antioxidant capacity to evaluate oxidative stress in 47 healthy full-term small-for-gestational age (SGA) newborns vs 67 appropriate-for-gestational age (AGA) newborns. Blood samples were collected at delivery from umbilical cord artery and vein and from peripheral blood of the babies on the third day after birth. Blood samples of mothers were also collected and compared with blood of 29 normal non-pregnant women (NPW). Serum peroxide values were significantly higher in both groups of mothers than in NPW, decreasing towards the third day in AGA mothers, while persisting in SGA mothers. Antioxidant capacity of sera of both groups of mothers was lower than NPW. Both SGA mothers and babies had increased MDA at delivery, unlike AGA counterparts. MDA levels in umbilical vein were higher than in umbilical arteries, while immunohistochemistry revealed abundant presence of 4-hydroxynonenal (HNE)-protein adducts only in stroma of the SGA placenta. These results show that both mothers and babies are exposed to oxidative stress during and after delivery, which is more pronounced and persistent in the perinatal period of the SGA group, while lipid peroxidation in placenta could play a role in SGA pathophysiology.     

Real-time in vivo visualization of oxidative stress in duckweed (Lemna minor L.)

An experimental set-up which enabled non-invasive, real-time reactive oxygen species (ROS) visualization on a whole plant level was constructed. In the test organism, Lemna minor L. (common duckweed), apoplastic and symplastic oxidative stress was evaluated by exposure to menadione (50 μM), menadione (50 μM) + ascorbate (100 μM) or neither for control. Menadione (50 μM) caused a statistically significant increase in H₂DCFDA fluorescence in the apoplast after 60 minutes of exposure. The addition of ascorbate (100 μM) in the test medium significantly decreased apoplastic oxidative stress. 50 μM menadione caused an increase in symplastic H₂DCFDA fluorescence in 57% of fronds. The exposure of L. minor plants to both menadione and ascorbate decreased the rate of fluorescence intensity accumulation in the symplast to control levels. The method has proven to be quick and straightforward and could be applied to a range of chemicals in various physiological and toxicological plant studies. The advantages of the set-up and different possible artefacts are discussed.     

Highly reactive cysteine residues are part of the substrate binding site of mammalian dipeptidyl peptidases III

Dipeptidyl peptidase III (DPP III) is a cytosolic zinc-exopeptidase involved in the intracellular protein catabolism of eukaryotes. Although inhibition by thiol reagents is a general feature of DPP III originating from various species, the function of activity important sulfhydryl groups is still inadequately understood. The present study of the reactivity of these groups was undertaken in order to clarify their biological significance.The inactivation kinetics of human and rat DPP III by sulfhydryl reagent p-hydroxy-mercuribenzoate (pHMB) was monitored by determination of the enzyme's residual activity with fluorimetric detection.Inactivation of this human enzyme exhibited pseudo-first-order kinetics, suggesting that all reactive SH-groups have equivalent reactivity, and the second-order rate constant was calculated to be 3523+/-567M(-1)min(-1). Rat DPP III was hyperreactive to pHMB and showed biphasic kinetics indicating two classes of reactive SH-groups. The second-order rate constants of 3540M(-1)s(-1) for slower reacting sulfhydryl, and 21,855M(-1)s(-1) for faster reacting sulfhydryl were obtained from slopes of linear plots of pseudo-first-order constants versus reagent concentration. Peptide substrates protected both mammalian DPPs III from inactivation by pHMB. Physiological concentrations of biological thiols and H(2)O(2) inactivated the rat DPP III. Human enzyme was resistant to H(2)O(2) attack and less affected by reduced glutathione (GSH) than the rat homologue. A significantly lower DPP III level, determined by activity measurement and Western blotting, was found in the cytosols of highly oxygenated rat tissues.These results provide kinetic evidence that cysteine residues are involved in substrate binding of mammalian DPPs III.     

Vaccination of mice with bacteria carrying a cloned herpesvirus genome reconstituted in vivo

Bacterial delivery systems are gaining increasing interest as potential vaccination vectors to deliver either proteins or nucleic acids for gene expression in the recipient. Bacterial delivery systems for gene expression in vivo usually contain small multicopy plasmids. We have shown before that bacteria containing a herpesvirus bacterial artificial chromosome (BAC) can reconstitute the virus replication cycle after cocultivation with fibroblasts in vitro. In this study we addressed the question of whether bacteria containing a single plasmid with a complete viral genome can also reconstitute the viral replication process in vivo. We used a natural mouse pathogen, the murine cytomegalovirus (MCMV), whose genome has previously been cloned as a BAC in Escherichia coli. In this study, we tested a new application for BAC-cloned herpesvirus genomes. We show that the MCMV BAC can be stably maintained in certain strains of Salmonella enterica serovar Typhimurium as well and that both serovar Typhimurium and E. coli harboring the single-copy MCMV BAC can reconstitute a virus infection upon injection into mice. By this procedure, a productive virus infection is regenerated only in immunocompromised mice. Virus reconstitution in vivo causes elevated titers of specific anti-MCMV antibodies, protection against lethal MCMV challenge, and strong expression of additional genes introduced into the viral genome. Thus, the reconstitution of infectious virus from live attenuated bacteria presents a novel concept for multivalent virus vaccines launched from bacterial vectors.     

Chromophore-apoprotein interactions in Synechocystis sp. PCC6803 phytochrome Cph1

The secondary, tertiary, and quaternary structures of the Synechocystis Cph1 phytochrome were investigated by absorption and circular dichroism spectroscopy, size exclusion chromatography, and limited proteolysis. The Cph1 protein was coexpressed with a bacterial thioredoxin in Escherichia coli, reconstituted in vitro with tetrapyrrole chromophores, and purified by chitin affinity chromatography. The resultant Cph1 holoproteins were essentially pure and had the specific absorbance ratio (SAR) of 0.8-0.9. Circular dichroism spectroscopy and limited proteolysis showed that the chromophore binding induced marked conformational changes in the Cph1 protein. The alpha-helical content increased to 42-44% in the holoproteins from 37% in the apoprotein. However, no significant difference in the secondary structure was detected between the Pr and Pfr forms. The tertiary structure of the Cph1 apoprotein appeared to be relatively flexible but became more compact and resistant to tryptic digestion upon chromophore binding. Interestingly, a small chromopeptide of about 30 kDa was still predominant even after longer tryptic digestion. The N-terminal location of this chromopeptide was confirmed by expression in E. coli and in vitro reconstitution with chromophores of the 32.5 kDa N-terminal fragment of the Cph1 protein. This chromopeptide was fully photoreversible with the spectral characteristic similar to that of the full-size Cph1 protein. The Cph1 protein forms dimers through the C-terminal region. These results suggest that the prokaryotic Cph1 phytochrome shares the structural and conformational characteristics of plant phytochromes, such as the two-domain structure consisting of the relatively compact N-terminal and the relatively flexible C-terminal regions, in addition to the chromophore-induced conformational changes.     

Cognitive control in adolescence: neural underpinnings and relation to self-report behaviors

Background

Adolescence is commonly characterized by impulsivity, poor decision-making, and lack of foresight. However, the developmental neural underpinnings of these characteristics are not well established.

Methodology/Principal Findings

To test the hypothesis that these adolescent behaviors are linked to under-developed proactive control mechanisms, the present study employed a hybrid block/event-related functional Magnetic Resonance Imaging (fMRI) Stroop paradigm combined with self-report questionnaires in a large sample of adolescents and adults, ranging in age from 14 to 25. Compared to adults, adolescents under-activated a set of brain regions implicated in proactive top-down control across task blocks comprised of difficult and easy trials. Moreover, the magnitude of lateral prefrontal activity in adolescents predicted self-report measures of impulse control, foresight, and resistance to peer pressure. Consistent with reactive compensatory mechanisms to reduced proactive control, older adolescents exhibited elevated transient activity in regions implicated in response-related interference resolution.

Conclusions/Significance

Collectively, these results suggest that maturation of cognitive control may be partly mediated by earlier development of neural systems supporting reactive control and delayed development of systems supporting proactive control. Importantly, the development of these mechanisms is associated with cognitive control in real-life behaviors.