Selenium Inhibits Proliferation Signaling and Restores Sodium/Potassium Pump Function of Diabetic Rat Aorta

Diabetes is characterized with increased oxidant stress, vasculopathy, and neuropathy. In diabetic vasculopathy, the observed thickening of the media and intima is not only a result of vascular smooth muscle cell proliferation but also due to modification of the extracellular matrix by these cells. Also, there is hampered membrane function and a reduction in sodium pump expression in the vessels of the diabetic animals. Selenium, being a trace element, has both insulinomimetic and antioxidant effects. Thus, we hypothesized that selenium treatment will reduce proliferation, restore physiology, and correct increased proliferation signaling of diabetic aorta. Diabetes was induced by streptozotocin (50 mg/kg body weight), and rats were then treated with sodium selenate (15 mumol/kg body weight/day) for 4 weeks. Our data from diabetic rats showed an increase in proliferation rate and matrix metalloproteinase activity in aortic cell cultures. We observed marked increases in MAPK phosphorylation and caveolin 1 expression but a decrease in Na(+)/K(+) ATPase activity in diabetic rat aorta homogenates. Selenium treatment resulted in complete normalization of the above parameters to control level, while it increased Na(+)/K(+) pump activity by 40%. Our results suggest that selenium treatment of diabetics can play beneficial role in protecting vascular architecture and function against diabetes-induced pathology.     

Oxidant and antioxidant status of Turkish marasmic children: A single center study

The aim of this study was to investigate plasma oxidant and antioxidant status in Turkish marasmic children. The study population consisted of 38 marasmic children (group I) and 28 age-matched children (group II) who were apparently well, with weight-forage >80% of the standards in the same region. After overnight fasting, venous blood samples were drawn and immediately transferred to heparinized and normal tubes. Plasma antioxidant potential (AOP), and malondialdehyde (MDA) levels were measured in both groups. The plasma MDA levels were found to be higher in group I than in group II. However, plasma AOP values were lower in group I than in group II. The present study suggests that AOP is reduced due to an impaired antioxidant system in the plasma of malnourished patients. This oxidant stress causes significant peroxidation. Also, the antioxidant defense system of the patients is deteriorated in marasmus.     

The antioxidant function of Sco proteins depends on a critical surface-exposed residue

BackgroundBesides their role in copper metabolism, Sco proteins from different organisms have been shown to play a defensive role against oxidative stress. In the present study, we set out to identify crucial amino acid residues for the antioxidant activity.MethodsNative and mutated Sco proteins from human, Arabidopsis thaliana and the yeast Kluyveromyces lactis were expressed in the model organism Saccharomyces cerevisiae. The oxidative stress resistance of the respective transformants was determined by growth and lipid peroxidation assays.ResultsA functionally important site, located 15 amino acids downstream of the well-conserved copper binding CxxxC motif, was identified. Mutational analysis revealed that a positive charge at this position has a detrimental effect on the antioxidant capacity. Bioinformatic analysis predicts that this site is surface-exposed, and according to Co-IP data it is required for binding of proteins that are connected to known antioxidant pathways.ConclusionThis study shows that the antioxidant capacity of eukaryotic Sco proteins is conserved and depends on the presence of functional site(s) rather than the extent of overall sequence homology.General significanceThese findings provide an insight into the conserved functional sites of eukaryotic Sco proteins that are crucial for combating oxidative stress. This capacity is probably not due to an enzymatic activity but rather is indirectly mediated by interaction with other proteins.     

DNA analysis in Turkish Duchenne/Becker muscular dystrophy families

Summary The molecular genetics of Duchenne/Becker muscular dystrophy was investigated in 81 affected Turkish families. Deletions were detected by multiplex polymerase chain reaction assays and cDNA Southern analyses. The distribution of the deletions along the gene and their correlation to clinical phenotype were different from the studies reported on other populations. Moreover, DNA polymorphisms in mothers were determined using 8 DNA probes and three CA repeat sequences, and a high degree of informativeness was observed.     

Dinucleotide repeat polymorphism at 11q23

A highly polymorphic CA repeat sequence was identified near the NCAM gene on chromosome 11q23. It should be a useful marker in the localization of genes responsible for neurological disorders that are known to map to this region.     

Methionine-enkephalin peptides in human teeth

The presence of the free opioid pentapeptide methionine enkephalin (ME) and of ME-containing peptide(s) was established firmly in decalcified, depulped human teeth by using a combination of methods including RP-HPLC, radioimmunoassay, radioreceptorassay, trypsin, carboxypeptidase B, fast atom bombardment mass spectrometry, and MS/MS methodology. Positive structural identification of ME was made with mass spectrometry. Those data demonstrate the presence of the preproenkephalinergic A system in the human trigeminal sensory termini.     

Separation of the minimal replication region of the F plasmid into a replication origin segment and a trans-acting segment

Summary An analysis was carried out on the replication functions within a 2.3 kilobase (kb) segment of the F plasmid which contains an origin (ori S) of replication and is capable of autonomous replication inEscherichia coli. Two separable regions were delineated for this segment: an origin region of approximately 1,140 bp in length and a segment of approximately 1,400 bp that functionsin trans to support replication of the origin region. The trans-acting segment is functional as part of an F replicon or when inserted into theE. coli chromosome. A prominent feature of the trans-acting segment is a coding sequence for a 29 K protein (Murotsu et al. 1981).     

Serotonin Receptor 6 Mediates Defective Brain Development in Monoamine Oxidase A-deficient Mouse Embryos

Monoamine oxidases A and B (MAO-A and MAO-B) are enzymes of the outer mitochondrial membrane that metabolize biogenic amines. In the adult central nervous system, MAOs have important functions for neurotransmitter homeostasis. Expression of MAO isoforms has been detected in the developing embryo. However, suppression of MAO-B does not induce developmental alterations. In contrast, targeted inhibition and knockdown of MAO-A expression (E7.5–E10.5) caused structural abnormalities in the brain. Here we explored the molecular mechanisms underlying defective brain development induced by MAO-A knockdown during in vitro embryogenesis. The developmental alterations were paralleled by diminished apoptotic activity in the affected neuronal structures. Moreover, dysfunctional MAO-A expression led to elevated levels of embryonic serotonin (5-hydroxytryptamine (5-HT)), and we found that knockdown of serotonin receptor-6 (5-Htr6) expression or pharmacologic inhibition of 5-Htr6 activity rescued the MAO-A knockdown phenotype and restored apoptotic activity in the developing brain. Our data suggest that excessive 5-Htr6 activation reduces activation of caspase-3 and -9 of the intrinsic apoptotic pathway and enhances expression of antiapoptotic proteins Bcl-2 and Bcl-XL. Moreover, we found that elevated 5-HT levels in MAO-A knockdown embryos coincided with an enhanced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and a reduction of proliferating cell numbers. In summary, our findings suggest that excessive 5-HT in MAO-A-deficient mouse embryos triggers cellular signaling cascades via 5-Htr6, which suppresses developmental apoptosis in the brain and thus induces developmental retardations.     

The killing of African trypanosomes by ethidium bromide

Introduced in the 1950s, ethidium bromide (EB) is still used as an anti-trypanosomal drug for African cattle although its mechanism of killing has been unclear and controversial. EB has long been known to cause loss of the mitochondrial genome, named kinetoplast DNA (kDNA), a giant network of interlocked minicircles and maxicircles. However, the existence of viable parasites lacking kDNA (dyskinetoplastic) led many to think that kDNA loss could not be the mechanism of killing. When recent studies indicated that kDNA is indeed essential in bloodstream trypanosomes and that dyskinetoplastic cells survive only if they have a compensating mutation in the nuclear genome, we investigated the effect of EB on kDNA and its replication. We here report some remarkable effects of EB. Using EM and other techniques, we found that binding of EB to network minicircles is low, probably because of their association with proteins that prevent helix unwinding. In contrast, covalently-closed minicircles that had been released from the network for replication bind EB extensively, causing them, after isolation, to become highly supertwisted and to develop regions of left-handed Z-DNA (without EB, these circles are fully relaxed). In vivo, EB causes helix distortion of free minicircles, preventing replication initiation and resulting in kDNA loss and cell death. Unexpectedly, EB also kills dyskinetoplastic trypanosomes, lacking kDNA, by inhibiting nuclear replication. Since the effect on kDNA occurs at a >10-fold lower EB concentration than that on nuclear DNA, we conclude that minicircle replication initiation is likely EB's most vulnerable target, but the effect on nuclear replication may also contribute to cell killing.     

Informed Consent Prior to Coronary Angiography in a Real World Scenario: What Do Patients Remember?

Background

Patients'' informed consent is legally essential before elective invasive cardiac angiography (CA) and successive intervention can be done. It is unknown to what extent patients can remember previous detailed information given by a specially trained doctor in an optimal scenario as compared to standard care.

Methodology/Principal Findings

In this prospective cohort study 150 consecutive in-patients and 50 out-patients were included before elective CA was initiated. The informed consent was provided and documented in in-patients by trained and instructed physicians the day before CA. In contrast, out-patients received standard information by different not trained physicians, who did not know about this investigation. All patients had to sign a form stating that enough information had been given and all questions had been answered sufficiently. One hour before CA an assessment of the patients'' knowledge about CA was performed using a standard point-by-point questionnaire by another independent physician. The supplied information was composed of 12 potential complications, 3 general, 4 periprocedural and 4 procedural aspects.95% of the patients felt that they had been well and sufficiently informed. Less than half of the potential complications could be remembered by the patients and more patients could remember less serious than life-threatening complications (27.9±8.8% vs. 47.1±11.0%; p<0.001). Even obvious complications like local bleeding could not be remembered by 35% of in-patients and 36% of out-patients (p = 0.87). Surprisingly, there were only a few knowledge differences between in- and out-patients.

Conclusions

The knowledge about CA of patients is vague when they give their informed consent. Even structured information given by a specially trained physician did not increase this knowledge.