Structural snapshots of base excision by the cancer-associated variant MutY N146S reveal a retaining mechanism.

DNA glycosylase MutY plays a critical role in suppression of mutations resulted from oxidative damage, as highlighted by cancer-association of the human enzyme. MutY requires a highly conserved catalytic Asp residue for excision of adenines misinserted opposite 8-oxo-7,8-dihydroguanine (OG). A nearby Asn residue hydrogen bonds to the catalytic Asp in structures of MutY and its mutation to Ser is an inherited variant in human MUTYH associated with colorectal cancer. We captured structural snapshots of N146S Geobacillus stearothermophilus MutY bound to DNA containing a substrate, a transition state analog and enzyme-catalyzed abasic site products to provide insight into the base excision mechanism of MutY and the role of Asn. Surprisingly, despite the ability of N146S to excise adenine and purine (P) in vitro, albeit at slow rates, N146S-OG:P complex showed a calcium coordinated to the purine base altering its conformation to inhibit hydrolysis. We obtained crystal structures of N146S Gs MutY bound to its abasic site product by removing the calcium from crystals of N146S-OG:P complex to initiate catalysis in crystallo or by crystallization in the absence of calcium. The product structures of N146S feature enzyme-generated ß-anomer abasic sites that support a retaining mechanism for MutY-catalyzed base excision.

Effect of Body Mass Index on Effectiveness of CT versus Invasive Coronary Angiography in Stable Chest Pain: The DISCHARGE Trial.

Background Recent trials support the role of cardiac CT in the evaluation of symptomatic patients suspected of having coronary artery disease (CAD); however, body mass index (BMI) has been reported to negatively impact CT image quality. Purpose To compare initial use of CT versus invasive coronary angiography (ICA) on clinical outcomes in patients with stable chest pain stratified by BMI category. Materials and Methods This prospective study represents a prespecified BMI subgroup analysis of the multicenter Diagnostic Imaging Strategies for Patients with Stable Chest Pain and Intermediate Risk of Coronary Artery Disease (DISCHARGE) trial conducted between October 2015 and April 2019. Adult patients with stable chest pain and a CAD pretest probability of 10%-60% were randomly assigned to undergo initial CT or ICA. The primary end point was major adverse cardiovascular events (MACE), including cardiovascular death, nonfatal myocardial infarction, or stroke. The secondary end point was an expanded MACE composite, including transient ischemic attack, and major procedure-related complications. Competing risk analyses were performed using the Fine and Gray subdistribution Cox proportional hazard model to assess the impact of the relationship between BMI and initial management with CT or ICA on the study outcomes, whereas noncardiovascular death and unknown causes of death were considered competing risk events. Results Among the 3457 participants included, 831 (24.0%), 1358 (39.3%), and 1268 (36.7%) had a BMI of less than 25, between 25 and 30, and greater than 30 kg/m2, respectively. No interaction was found between CT or ICA and BMI for MACE (P = .29), the expanded MACE composite (P = .38), or major procedure-related complications (P = .49). Across all BMI subgroups, expanded MACE composite events (CT, 10 of 409 [2.4%] to 23 of 697 [3.3%]; ICA, 26 of 661 [3.9%] to 21 of 422 [5.1%]) and major procedure-related complications during initial management (CT, one of 638 [0.2%] to five of 697 [0.7%]; ICA, nine of 630 [1.4%] to 12 of 422 [2.9%]) were less frequent in the CT versus ICA group. Participants with a BMI exceeding 30 kg/m² exhibited a higher nondiagnostic CT rate (7.1%, P = .044) compared to participants with lower BMI. Conclusion There was no evidence of a difference in outcomes between CT and ICA across the three BMI subgroups. Clinical trial registration no. NCT02400229 © RSNA, 2024 Supplemental material is available for this article.

Carotid artery plaque composition and distribution: near-infrared spectroscopy and intravascular ultrasound analysis.

Most atherosclerotic plaques (APs) form in typical predilection areas of low endothelial shear stress (ESS). On the contrary, previous data hinted that plaques rupture in their proximal parts where accelerated blood flow causes high ESS. It was postulated that high ESS plays an important role in the latter stages of AP formation and in its destabilization. Here, we used near-infrared spectroscopy (NIRS) to analyse the distribution of lipid core based on the presumed exposure to ESS. A total of 117 carotid arteries were evaluated using NIRS and intravascular ultrasound (IVUS) prior to carotid artery stenting. The point of minimal luminal area (MLA) was determined using IVUS. A stepwise analysis of the presence of lipid core was then performed using NIRS. The lipid core presence was quantified as the lipid core burden index (LCBI) within 2 mm wide segments both proximally and distally to the MLA. The analysed vessel was then divided into three 20 mm long thirds (proximal, middle, and distal) for further analysis. The maximal value of LCBI (231.9 ± 245.7) was noted in the segment localized just 2 mm proximally to MLA. The mean LCBI in the middle third was significantly higher than both the proximal (121.4 ± 185.6 vs. 47.0 ± 96.5, P < 0.01) and distal regions (121.4 ± 185.6 vs. 32.4 ± 89.6, P < 0.01). Lipid core was more common in the proximal region when compared with the distal region (mean LCBI 47.0 ± 96.5 vs. 32.4 ± 89.6, P < 0.01).

RPE65 has an additional function as the lutein to meso-zeaxanthin isomerase in the vertebrate eye.

Carotenoids are plant-derived pigment molecules that vertebrates cannot synthesize de novo that protect the fovea of the primate retina from oxidative stress and light damage. meso-Zeaxanthin is an ocular-specific carotenoid for which there are no common dietary sources. It is one of the three major carotenoids present at the foveal center, but the mechanism by which it is produced in the eye is unknown. An isomerase enzyme is thought to be responsible for the transformation of lutein to meso-zeaxanthin by a double-bond shift mechanism, but its identity has been elusive. We previously found that meso-zeaxanthin is produced in a developmentally regulated manner in chicken embryonic retinal pigment epithelium (RPE)/choroid in the absence of light. In the present study, we show that RPE65, the isomerohydrolase enzyme of the vertebrate visual cycle that catalyzes the isomerization of all-trans-retinyl esters to 11-cis-retinol, is also the isomerase enzyme responsible for the production of meso-zeaxanthin in vertebrates. Its RNA is up-regulated 23-fold at the time of meso-zeaxanthin production during chicken eye development, and we present evidence that overexpression of either chicken or human RPE65 in cell culture leads to the production of meso-zeaxanthin from lutein. Pharmacologic inhibition of RPE65 function resulted in significant inhibition of meso-zeaxanthin biosynthesis during chicken eye development. Structural docking experiments revealed that the epsilon ring of lutein fits into the active site of RPE65 close to the nonheme iron center. This report describes a previously unrecognized additional activity of RPE65 in ocular carotenoid metabolism.

Structure and stereochemistry of the base excision repair glycosylase MutY reveal a mechanism similar to retaining glycosidases.

MutY adenine glycosylases prevent DNA mutations by excising adenine from promutagenic 8-oxo-7,8-dihydroguanine (OG):A mismatches. Here, we describe structural features of the MutY active site bound to an azaribose transition state analog which indicate a catalytic role for Tyr126 and approach of the water nucleophile on the same side as the departing adenine base. The idea that Tyr126 participates in catalysis, recently predicted by modeling calculations, is strongly supported by mutagenesis and by seeing close contact between the hydroxyl group of this residue and the azaribose moiety of the transition state analog. NMR analysis of MutY methanolysis products corroborates a mechanism for adenine removal with retention of stereochemistry. Based on these results, we propose a revised mechanism for MutY that involves two nucleophilic displacement steps akin to the mechanisms accepted for 'retaining' O-glycosidases. This new-for-MutY yet familiar mechanism may also be operative in related base excision repair glycosylases and provides a critical framework for analysis of human MutY (MUTYH) variants associated with inherited colorectal cancer.

Classifying neuronal subclasses of the cerebellum through constellation pharmacology.

A pressing need in neurobiology is the comprehensive identification and characterization of neuronal subclasses within the mammalian nervous system. To this end, we used constellation pharmacology as a method to interrogate the neuronal and glial subclasses of the mouse cerebellum individually and simultaneously. We then evaluated the data obtained from constellation-pharmacology experiments by cluster analysis to classify cells into neuronal and glial subclasses, based on their functional expression of glutamate, acetylcholine, and GABA receptors, among other ion channels. Conantokin peptides were used to identify N-methyl-d-aspartate (NMDA) receptor subtypes, which revealed that neurons of the young mouse cerebellum expressed NR2A and NR2B NMDA receptor subunits. Additional pharmacological tools disclosed differential expression of α-amino-3-hydroxy-5-methyl-4-isoxazloepropionic, nicotinic acetylcholine, and muscarinic acetylcholine receptors in different neuronal and glial subclasses. Certain cell subclasses correlated with known attributes of granule cells, and we combined constellation pharmacology with genetically labeled neurons to identify and characterize Purkinje cells. This study illustrates the utility of applying constellation pharmacology to classify neuronal and glial subclasses in specific anatomical regions of the brain.

Convergent Evolution of Head Crests in Two Domesticated Columbids Is Associated with Different Missense Mutations in EphB2.

Head crests are important display structures in wild bird species and are also common in domesticated lineages. Many breeds of domestic rock pigeon (Columba livia) have crests of reversed occipital feathers, and this recessive trait is associated with a nonsynonymous coding mutation in the intracellular kinase domain of EphB2 (Ephrin receptor B2). The domestic ringneck dove (Streptopelia risoria) also has a recessive crested morph with reversed occipital feathers, and interspecific crosses between crested doves and pigeons produce crested offspring, suggesting a similar genetic basis for this trait in both species. We therefore investigated EphB2 as a candidate for the head crest phenotype of ringneck doves and identified a nonsynonymous coding mutation in the intracellular kinase domain that is significantly associated with the crested morph. This mutation is over 100 amino acid positions away from the crest mutation found in rock pigeons, yet both mutations are predicted to negatively affect the function of ATP-binding pocket. Furthermore, bacterial toxicity assays suggest that "crest" mutations in both species severely impact kinase activity. We conclude that head crests are associated with different mutations in the same functional domain of the same gene in two different columbid species, thereby representing striking evolutionary convergence in morphology and molecules.

Prey-Capture Strategies of Fish-Hunting Cone Snails: Behavior, Neurobiology and Evolution.

The venomous fish-hunting cone snails (Conus) comprise eight distinct lineages evolved from ancestors that preyed on worms. In this article, we attempt to reconstruct events resulting in this shift in food resource by closely examining patterns of behavior, biochemical agents (toxins) that facilitate prey capture and the combinations of toxins present in extant species. The first sections introduce three different hunting behaviors associated with piscivory: 'taser-and-tether', 'net-engulfment' and 'strike-and-stalk'. The first two fish-hunting behaviors are clearly associated with distinct groups of venom components, called cabals, which act in concert to modify the behavior of prey in a specific manner. Derived fish-hunting behavior clearly also correlates with physical features of the radular tooth, the device that injects these biochemical components. Mapping behavior, biochemical components and radular tooth features onto phylogenetic trees shows that fish-hunting behavior emerged at least twice during evolution. The system presented here may be one of the best examples where diversity in structure, physiology and molecular features were initially driven by particular pathways selected through behavior.

[Detection of vulnerable atherosclerotic plaque with near-infrared spectroscopy: a systematic review]. / Význam vulnerabilních aterosklerotických plátu a moznosti jejich detekce pomocí intravaskulární spektroskopie.

The term vulnerable atherosclerotic plaque is used to describe an atherosclerotic lesion with a high probability of rupture and thrombosis causing an acute coronary event or stroke. Pathogenesis of the vulnerable plaque has been well described pathologically and on experimental models. Detection of vulnerable plaques in vivo has been limited so far. There has been lack of methods able to predict future event from certain lesion characteristics that were rigorously validated on prospective clinical trials. Intravascular near-infrared spectroscopy is a novel technique that has been intentionally developed for the identification of a lipid core within a plaque. Results from recent clinical trials seem promising. This review briefly summarizes current knowledge in the field of near-infrared spectroscopy.

Structural anatomy of telomere OB proteins.

Telomere DNA-binding proteins protect the ends of chromosomes in eukaryotes. A subset of these proteins are constructed with one or more OB folds and bind with G+T-rich single-stranded DNA found at the extreme termini. The resulting DNA-OB protein complex interacts with other telomere components to coordinate critical telomere functions of DNA protection and DNA synthesis. While the first crystal and NMR structures readily explained protection of telomere ends, the picture of how single-stranded DNA becomes available to serve as primer and template for synthesis of new telomere DNA is only recently coming into focus. New structures of telomere OB fold proteins alongside insights from genetic and biochemical experiments have made significant contributions towards understanding how protein-binding OB proteins collaborate with DNA-binding OB proteins to recruit telomerase and DNA polymerase for telomere homeostasis. This review surveys telomere OB protein structures alongside highly comparable structures derived from replication protein A (RPA) components, with the goal of providing a molecular context for understanding telomere OB protein evolution and mechanism of action in protection and synthesis of telomere DNA.

Metagenome mining and functional analysis reveal oxidized guanine DNA repair at the Lost City Hydrothermal Field.

The GO DNA repair system protects against GC → TA mutations by finding and removing oxidized guanine. The system is mechanistically well understood but its origins are unknown. We searched metagenomes and abundantly found the genes encoding GO DNA repair at the Lost City Hydrothermal Field (LCHF). We recombinantly expressed the final enzyme in the system to show MutY homologs function to suppress mutations. Microbes at the LCHF thrive without sunlight, fueled by the products of geochemical transformations of seafloor rocks, under conditions believed to resemble a young Earth. High levels of the reductant H2 and low levels of O2 in this environment raise the question, why are resident microbes equipped to repair damage caused by oxidative stress? MutY genes could be assigned to metagenome-assembled genomes (MAGs), and thereby associate GO DNA repair with metabolic pathways that generate reactive oxygen, nitrogen and sulfur species. Our results indicate that cell-based life was under evolutionary pressure to cope with oxidized guanine well before O2 levels rose following the great oxidation event.

Increased cardiovascular mortality in patients with mechanically expandable transcatheter aortic valve and without permanent pacemaker.

INTRODUCTION: Use of the mechanically expandable transcatheter aortic valve (MEV) has been recently linked to increased risks of valve dysfunction and cardiovascular mortality. The risk of developing conduction disturbance with the MEV valve is well known, and the negative prognostic impact of permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation is another consideration. AIM: This study aimed to compare the mid-term survival of patients with MEV and self-expandable valves (SEV), and to examine survival of both groups according to the presence or absence of PPI. METHODS: This single-centre, retrospective, observational study examined data from MEV and SEV groups comprising 92 and 373 patients, respectively. The mean clinical follow-up was 2.5±1.7 years. Mortality information was obtained from the National Institutes of Health Information and Statistics. RESULTS: Baseline characteristics were comparable between the groups. The log-rank test showed higher cardiovascular mortality in the MEV group (p=0.042; the relative risk (RR) 1.594 (95% CI 1.013 to 2.508)). The Cox proportional hazards model identified MEV implantation as an independent predictor of cardiovascular mortality. The rate of PPI was twice as high in the MEV vs SEV group (33.7% vs 16.1%; p<0.001). We compared the survival of both groups according to the presence or absence of PPI and found higher mortality in the MEV group without PPI versus the SEV group without PPI (p=0.007; RR 2.156 (95% CI 1.213 to 3.831)). Survival did not differ in the groups with PPI. CONCLUSIONS: A higher mid-term cardiovascular mortality rate was observed with MEV versus SEV implants. Comparing both groups according to the presence or absence of PPI, we observed a higher mortality risk in patients with MEV without PPI than in SEV without PPI. In contrast, mortality did not differ between the groups when PPI was implanted.

Computed Tomography Versus Invasive Coronary Angiography in Patients With Diabetes and Suspected Coronary Artery Disease.

OBJECTIVE: To compare cardiac computed tomography (CT) with invasive coronary angiography (ICA) as the initial strategy in patients with diabetes and stable chest pain. RESEARCH DESIGN AND METHODS: This prespecified analysis of the multicenter DISCHARGE trial in 16 European countries was performed in patients with stable chest pain and intermediate pretest probability of coronary artery disease. The primary end point was a major adverse cardiac event (MACE) (cardiovascular death, nonfatal myocardial infarction, or stroke), and the secondary end point was expanded MACE (including transient ischemic attacks and major procedure-related complications). RESULTS: Follow-up at a median of 3.5 years was available in 3,541 patients of whom 557 (CT group n = 263 vs. ICA group n = 294) had diabetes and 2,984 (CT group n = 1,536 vs. ICA group n = 1,448) did not. No statistically significant diabetes interaction was found for MACE (P = 0.45), expanded MACE (P = 0.35), or major procedure-related complications (P = 0.49). In both patients with and without diabetes, the rate of MACE did not differ between CT and ICA groups. In patients with diabetes, the expanded MACE end point occurred less frequently in the CT group than in the ICA group (3.8% [10 of 263] vs. 8.2% [24 of 294], hazard ratio [HR] 0.45 [95% CI 0.22-0.95]), as did the major procedure-related complication rate (0.4% [1 of 263] vs. 2.7% [8 of 294], HR 0.30 [95% CI 0.13 - 0.63]). CONCLUSIONS: In patients with diabetes referred for ICA for the investigation of stable chest pain, a CT-first strategy compared with an ICA-first strategy showed no difference in MACE and may potentially be associated with a lower rate of expanded MACE and major procedure-related complications.

Structure of a serine protease poised to resynthesize a peptide bond.

The serine proteases are among the most thoroughly studied enzymes, and numerous crystal structures representing the enzyme-substrate complex and intermediates in the hydrolysis reactions have been reported. Some aspects of the catalytic mechanism remain controversial, however, especially the role of conformational changes in the reaction. We describe here a high-resolution (1.46 A) crystal structure of a complex formed between a cleaved form of bovine pancreatic trypsin inhibitor (BPTI) and a catalytically inactive trypsin variant with the BPTI cleavage site ideally positioned in the active site for resynthesis of the peptide bond. This structure defines the positions of the newly generated amino and carboxyl groups following the 2 steps in the hydrolytic reaction. Comparison of this structure with those representing other intermediates in the reaction demonstrates that the residues of the catalytic triad are positioned to promote each step of both the forward and reverse reaction with remarkably little motion and with conservation of hydrogen-bonding interactions. The results also provide insights into the mechanism by which inhibitors like BPTI normally resist hydrolysis when bound to their target proteases.

Mid-term outcomes of patients with Lotus and Evolut transcatheter valves.

Introduction: Long-term data on the Lotus® (Boston Scientific, USA) valve are lacking. Aim: To evaluate mid-term outcomes of aortic stenosis patients treated with either Lotus or Evolut R® valves (Medtronic, USA). Material and methods: Our study sample comprised 190 patients (71 Lotus and 119 Evolut valves). The mean clinical follow-up was 2.0 ±0.9 years. Information on mortality was obtained from the National Institutes of Health Information and Statistics. Results: No significant differences existed in baseline characteristics between the groups. The rate of procedural complications was low and without significant differences between groups. The log rank test showed higher mortality in the Lotus group for cardiovascular mortality (p = 0.02; RR = 2.4, 95% CI: 1.123-5.075). Multivariable analysis revealed that the Lotus valve was independently associated with cardiovascular mortality (p = 0.03). At the end of echocardiography follow-up (4.1 ±0.9 years), we found a significantly higher mean aortic valve gradient (AVGm) in the Lotus group than in the Evolut group (17.9 ±9.5 vs. 10.2 ±3.5 mm Hg; p = 0.0006), and 3 (10%) patients from the Lotus group suffered from symptomatic re-stenosis requiering re-intervention. Conclusions: The results of our study suggest that higher cardiovascular mortality rates during mid-term follow-up were associated with Lotus compared with Evolut valves. Higher AVGm in the Lotus valves suggests the possibility of accelerated prosthesis degeneration.

Screening and Risk Stratification Strategy Reduced Decompression Sickness Occurrence in Divers With Patent Foramen Ovale.

OBJECTIVES: This paper sought to evaluate the occurrence of decompression sickness (DCS) after the application of a patent foramen ovale (PFO) screening and risk stratification strategy. BACKGROUND: PFO is associated with an increased risk of DCS. Recently, transcatheter closure was reported to reduce DCS occurrence in divers with a high-grade shunt. However, to date, there are no data regarding the effectiveness of any PFO screening and risk stratification strategy for divers. METHODS: A total of 829 consecutive divers (age 35.4 ± 10.0 years, 81.5% men) were screened for PFO by means of transcranial color-coded sonography in the DIVE-PFO (Decompression Illness Prevention in Divers with a Patent Foramen Ovale) registry. Divers with a high-grade PFO were offered either catheter-based PFO closure (the closure group) or advised conservative diving (high grades). Divers with a low-grade shunt were advised conservative diving (low grades), whereas those with no PFO continued unrestricted diving (controls). A telephone follow-up was performed. To study the effect of the screening and risk stratification strategy, DCS occurrence before enrollment and during the follow-up was compared. RESULTS: Follow-up was available for 748 (90%) divers. Seven hundred and 2 divers continued diving and were included in the analysis (mean follow-up 6.5 ± 3.5 years). The DCS incidence decreased significantly in all groups, except the controls. During follow-up, there were no DCS events in the closure group; DCS incidence was similar to the controls in the low-grade group (HR: 3.965; 95% CI: 0.558-28.18; P = 0.169) but remained higher in the high-grade group (HR: 26.170; 95% CI: 5.797-118.160; P < 0.0001). CONCLUSIONS: The screening and risk stratification strategy using transcranial color-coded sonography was associated with a decrease in DCS occurrence in divers with PFO. Catheter-based PFO closure was associated with a DCS occurrence similar to the controls; the conservative strategy had a similar effect in the low-grade group, but in the high-grade group the DCS incidence remained higher than in all other groups.

Long-term changes after carotid stenting assessed by intravascular ultrasound and near-infrared spectroscopy.

BACKGROUND: Long-term effect of carotid stenting (CAS) on the stabilization of the plaque is almost unrecognized. Vascular healing and remodeling might seal the atherosclerotic plaque with neointimal hyperplasia decreasing the vulnerability. We aimed to assess long-term change in the lipid signal, stent and luminal dimensions and restenosis after CAS with the intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. METHODS: We performed follow-up angiography and NIRS-IVUS imaging of 58 carotid stents in 52 patients. Median time from CAS to the follow-up examination was 31 months (range, 5-56). The lipid signal of the stented segment was calculated from a NIRS-derived chemogram (a spectroscopic map) as the lipid core burden index (LCBI, a dimensionless number from 0 to 1,000). Planimetric and volumetric measurements from IVUS were performed to assess change in minimal stent area (MSA), minimal luminal area (MLA), stent and luminal volume, late stent expansion and percentage in-stent restenosis (ISR) volume. RESULTS: During the follow-up period, the mean (±SD) LCBI significantly decreased from 32±56 to 17±27 (P=0.002). The mean stent volume significantly increased from 717±302 to 1,019±429 mm3 (P<0.001) with mean stent expansion 43%±24%. The mean luminal volume increased from 717±302 to 760±359 mm3 (P=0.025) due to ISR encroaching 26%±15% of the stent volume. CONCLUSIONS: Lipid signal decreased during the follow-up period suggesting stabilization of the plaque. Late stent expansion was balanced with neointimal hyperplasia. TRIAL REGISTRATION: The trial is registered under clinicaltrials.gov NCT03141580.

Long-term survival of carotid stenting patients with regard to single- or double-vessel carotid artery disease: a propensity score matching analysis.

INTRODUCTION: There is lack of long-term data outside of controlled clinical trials in carotid artery stenting (CAS). In this study, we compared the short-term outcome, long-term survival, and rate of re-interventions for restenosis in patients after CAS, related to the extent of carotid atherosclerosis classified as single-vessel (unilateral) or double-vessel (bilateral) carotid artery disease. MATERIAL AND METHODS: We retrospectively evaluated 599 patients with significant carotid artery stenosis, who underwent 763 CAS procedures, and used the propensity score to match 226 pairs (452 patients) in the single- or double-vessel carotid disease. RESULTS: There was no significant difference in the occurrence of in-hospital major adverse events (3.5% vs. 3.1% of patients in the double-vessel carotid group vs. the single-vessel carotid group; p = 1) The mean follow-up was 6.1 ±4.0 years, and a total of 181 (40%) deaths occurred during 2759 patient-years, which translates into 7.8 and 5.3 deaths per 100 patient-years in the double-vessel carotid group and the single-vessel carotid group, respectively (p < 0.01). The survival in the double-vessel carotid group vs. the single-vessel carotid group at 10 years was 46% (95% CI: 38-54%) vs. 55% (95% CI: 47-63%) (p < 0.01). Twenty-four (11%) patients and 6 (3%) patients underwent re-interventions for restenosis in the double-vessel and the single-vessel carotid disease group, respectively (p < 0.01). CONCLUSIONS: Patients with CAS and significant double-vessel carotid artery disease had similar peri-procedural risk, but had a worse long-term survival, and a higher rate of re-interventions for restenosis compared to the single-vessel carotid artery disease patients.

MicroRNA-331 and microRNA-151-3p as biomarkers in patients with ST-segment elevation myocardial infarction.

We sought to analyse plasma levels of peripheral blood microRNAs (miRs) as biomarkers of ST-segment-elevation myocardial infarction (STEMI) due to type-1 myocardial infarction as a model situation of vulnerable plaque (VP) rupture. Samples of 20 patients with STEMI were compared both with a group of patients without angina pectoris in whom coronary angiogram did not reveal coronary atherosclerotic disease (no coronary atherosclerosis-NCA) and a group of patients with stable angina pectoris and at least one significant coronary artery stenosis (stable coronary artery disease-SCAD). This study design allowed us to identify miRs deregulated in the setting of acute coronary artery occlusion due to VP rupture. Based on an initial large scale miR assay screening, we selected a total of 12 miRs (three study miRs and nine controls) that were tested in the study. Two of the study miRs (miR-331 and miR-151-3p) significantly distinguished STEMI patients from the control groups, while ROC analysis confirmed their suitability as biomarkers. Importantly, this was observed in patients presenting early with STEMI, even before the markers of myocardial necrosis (cardiac troponin I, miR-208 and miR-499) were elevated, which suggests that the origin of miR-331 and miR-151-3p might be in the VP. In conclusion, the study provides two novel biomarkers observed in STEMI, which may be associated with plaque rupture.

Structural Basis for Finding OG Lesions and Avoiding Undamaged G by the DNA Glycosylase MutY.

The adenine glycosylase MutY selectively initiates repair of OG:A lesions and, by comparison, avoids G:A mispairs. The ability to distinguish these closely related substrates relies on the C-terminal domain of MutY, which structurally resembles MutT. To understand the mechanism for substrate specificity, we crystallized MutY in complex with DNA containing G across from the high-affinity azaribose transition state analogue. Our structure shows that G is accommodated by the OG site and highlights the role of a serine residue in OG versus G discrimination. The functional significance of Ser308 and its neighboring residues was evaluated by mutational analysis, revealing the critical importance of a ß loop in the C-terminal domain for mutation suppression in cells, and biochemical performance in vitro. This loop comprising residues Phe307, Ser308, and His309 (Geobacillus stearothermophilus sequence positions) is conserved in MutY but absent in MutT and other DNA repair enzymes and may therefore serve as a MutY-specific target exploitable by chemical biological probes.