Aortic arch mechanics measured with two-dimensional speckle tracking echocardiography.

PURPOSE: To study the feasibility of vascular mechanics at the aortic arch with two-dimensional speckle tracking echocardiography, as well as to define normal values and to compare results between hypertensive patients and healthy patients. METHODS: We included 107 patients (61 healthy patients and 46 hypertensive patients) who underwent a complete echocardiographic exam, including a short-axis view of the aortic arch. The speckle tracking methodology was used to calculate aortic arch mechanics offline (EchoPAC; GE Healthcare). The analysis was performed for circumferential aortic strain and for the early circumferential aortic strain rate, and we used an average result of the six equidistant segments of the arterial wall. We also assessed the aortic pulse wave velocity with the Complior method. RESULTS: The 61 healthy patients had a mean age of 33 ±â€Š9 years, and 59% were women. Of the total 366 aortic arch wall segments, 344 (94%) had adequate waveforms for the speckle tracking analysis. The hypertensive patients had a mean age of 45 ±â€Š12 years, and 54% were women. Of the total 276 aortic wall segments, 261 (95%) had adequate waveforms for analysis. Aortic arch strain and strain rate were lower in the hypertensive patients group than in the healthy patients group (6.3 ±â€Š2.0 vs. 11.2 ±â€Š3.2% and 1.0 ±â€Š0.3 vs. 1.5 ±â€Š0.4 s(-1), respectively, both P < 0.01). Aortic arch strain and strain were correlated with age (r = -0.62, r = -0.54; P < 0.01), pulse pressure (r = -0.48, r = -0.39; P < 0.01) and the pulse wave velocity (r = -0.57, r = -0.54; P < 0.01). After adjustments for age, sex and BMI, strain was significantly lower in hypertensive patients, when compared with healthy patients. CONCLUSION: Speckle tracking analysis of aortic arch images is feasible and might serve as a new approach to evaluate arterial function.

The monoheme cytochrome c subunit of Alternative Complex III is a direct electron donor to caa3 oxygen reductase in Rhodothermus marinus.

Alternative Complex III (ACIII) is an example of the robustness and flexibility of prokaryotic respiratory chains. It performs quinol:cytochrome c oxidoreductase activity, being functionally equivalent to the bc1 complex but structurally unrelated. In this work we further explored ACIII investigating the role of its monoheme cytochrome c subunit (ActE). We expressed and characterized the individually isolated ActE, which allowed us to suggest that ActE is a lipoprotein and to show its function as a direct electron donor to the caa3 oxygen reductase.

Changes in Peripheral Refractive Profile after Orthokeratology for Different Degrees of Myopia.

PURPOSE: The purpose of this study was to evaluate the effect of orthokeratology for different degrees of myopia correction in the relative location of tangential (F(T)) and sagittal (F(S)) power errors across the central 70° of the visual field in the horizontal meridian. METHODS: Thirty-four right eyes of 34 patients with a mean age of 25.2 ± 6.4 years were fitted with Paragon CRT (Mesa, AZ) rigid gas permeable contact lenses to treat myopia (-2.15 ± 1.26D, range: -0.88 to -5.25D). Axial and peripheral refraction were measured along the central 70° of the horizontal visual field with the Grand Seiko WAM5500 open-field auto-refractor. Spherical equivalent (M), as well as tangential (FT) and sagittal power errors (FS) were obtained. Analysis was stratified in three groups according to baseline spherical equivalent: Group 1 [M(Baseline) = -0.88 to -1.50D; n = 11], Group 2 [M(Baseline) = -1.51 to -2.49D; n = 11], and Group 3 [M(Baseline) = -2.50 to -5.25D; n = 12]. RESULTS: Spherical equivalent was significantly more myopic after treatment beyond the central 40° of the visual field (p < 0.001). FT became significantly more myopic for all groups in the nasal and temporal retina with 25° (p ≤ 0.017), 30° (p ≤ 0.007) and 35° (p ≤ 0.004) of eye rotation. Myopic change in FS was less consistent, achieving only statistical significance for all groups at 35° in the nasal and temporal retina (p ≤ 0.045). CONCLUSIONS: Orthokeratology changes significantly FT in the myopic direction beyond the central 40° of the visual field for all degrees of myopia. Changes induced by orthokeratology in relative peripheral M, FT and FS with 35° of eye rotation were significantly correlated with axial myopia at baseline.

Stabilization in early adult-onset myopia with corneal refractive therapy.

PURPOSE: To describe the stabilization of early adult-onset myopia in three university students after initiating orthokeratology treatment with corneal refractive therapy contact lenses. METHODS: Three Caucasian early adult-onset progressing myopic subjects (1 male, 2 females) were fitted with corneal refractive therapy lenses to correct myopia between -1.50 and -2.50 D of sphere using Paragon CRT (Paragon Vision Sciences, Mesa, AZ) lenses for overnight orthokeratology. The pre-treatment refractive history from 2005 as well as refraction and axial length after treatment onset are reported over a period of 3 years between December 2009 and January 2013 with an additional year of follow-up after treatment discontinuation (January-December 2013). The peripheral refractive patterns and topographic changes are also reported individually. RESULTS: Treatment was successful in all three subjects achieving uncorrected visual acuity of 20/20 or better monocularly. During a period of 3 years of follow-up the subjects did not experience progression in their refractive error, nor in their axial length (measured during the last 2 years of treatment and 1 year after discontinuation). Furthermore, the subjects recovered to their baseline refraction and did not progressed further over the following year after lens wear discontinuation. CONCLUSIONS: We cannot attribute a causative effect to the orthokeratology treatment alone as underlying mechanism for myopia stabilization in this 3 patients. However, the present report points to the possibility of stabilization of early adult-onset myopia progression in young adults using corneal refractive therapy treatment.

Prognosis following acute coronary syndromes according to prior coronary artery bypass grafting: Meta-analysis.

PURPOSE: Conduct a meta-analysis to study the prognostic influence of a previous coronary artery bypass grafting (CABG) in patients admitted for an acute coronary syndrome (ACS). METHODS: A systematic review of the literature was performed using electronic reference databases through January 2013 (MEDLINE, Cochrane Library, Web of Knowledge, Google Scholar and references cited in other studies). Studies in which ACS outcomes with a previous history of CABG were compared with ACS outcomes with no history of previous CABG were considered for inclusion. The main endpoints of interest were mortality and non-fatal acute myocardial infarction. Data was aggregated at three follow-up times using random-effects meta-analysis models. RESULTS: Twenty-four studies were included which provided 387,181 patients for analysis. Previous CABG ACS patients were older, more diabetic and had a more frequent history of a previous myocardial infarction. Pooled in-hospital mortality was higher for the previous CABG ACS patients (OR 1.22 [1.04-1.44], p<0.01, I(2) 88%). The pooled adjusted OR showed no significant differences for the two groups (adjusted OR 1.13 [0.93-1.37], p=0.22, I(2) 92%). Previous CABG ACS patient had a higher pooled 30-day mortality (OR 1.28 [1.05-1.55], p=0.02, I(2) 74%); a higher non-adjusted (OR 1.61 [1.38-1.88], p<0.01, I(2) 70%) and adjusted (adjusted OR 1.37 [1.15-1.65], p<0.01, I(2) 0%) long-term mortality. Both the in-hospital and the long-term re-infarction rates were higher for the previous CABG ACS patients. CONCLUSIONS: According to our data, ACS patients with previous CABG history had a higher risk for short- and long-term adverse events.

Structural composition of alternative complex III: variations on the same theme.

Alternative complex III forms a recently identified family of enzymes with quinol:electron acceptor oxidoreductase activity. First biochemical and genomic analyses showed that ACIII is composed of six to eight subunits, most of which homologous to different proteins or domains already observed in other known enzymatic complexes. The increasing number of completely sequenced genomes led us to perform a new search for the genes coding for the different ACIII subunits. We have identified a larger number of gene clusters coding for ACIII, still confined to the bacterial domain, but extended to classes in which it was not observed before. We also found an unanticipated diversity in gene clusters, both in terms of its constitution and organization. The several unexpected gene arrangements brought new perspectives to the role of the different subunits of ACIII, namely in quinone binding and in proton translocation. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.

The superfamily of heme-copper oxygen reductases: types and evolutionary considerations.

Heme-copper oxygen reductases (HCO) reduce O(2) to water being the last enzymatic complexes of most aerobic respiratory chains. These enzymes promote energy conservation coupling the catalytic reaction to charge separation and charge translocation across the prokaryotic cytoplasmatic or mitochondrial membrane. In this way they contribute to the establishment and maintenance of the transmembrane difference of electrochemical potential, which is vital for solute/nutrient cell import, synthesis of ATP and motility. The HCO enzymes most probably share with the nitric oxide reductases, NORs, a common ancestor. We have proposed the classification of HCOs into three different types, A, B and C; based on the constituents of their proton channels (Pereira, Santana and Teixeira (2001) Biochim Biophys Acta, 1505, 185-208). This classification was recently challenged by the suggestion of other different types of HCOs. Using an enlarged sampling we performed an exhaustive bioinformatic reanalysis of HCOs family. Our results strengthened our previously proposed classification and showed no need for the existence of more divisions. Now, we analyze the taxonomic distribution of HCOs and NORs and the congruence of their sequence trees with the 16S rRNA tree. We observed that HCOs are widely distributed in the two prokaryotic domains and that the different types of enzymes are not confined to a specific taxonomic group or environmental niche.