Mini-extracorporeal circulation minimizes coagulation abnormalities and ameliorates pulmonary outcome in coronary artery bypass grafting surgery

Hemostasis is impaired during CABG and coagulation abnormalities often result in clinically relevant organ dysfunctions, eventually increasing morbidity and mortality rates. Fifteen consecutive patients with coronary artery disease submitted to conventional extracorporeal circulation (cECC) have been compared with 15 matched patients, using mini-ECC (MECC). Postoperative lung function was evaluated according to gas exchange, intubation time and lung injury score. In the MECC group, thrombin-antithrombin complex levels (TaTc), prothrombin fragments (PF1+2) formation and thromboelastography (TEG) clotting times were lower compared to the cECC group (p=0.002 and p<0.001, respectively) whereas postoperative blood loss was higher in the cECC group (p=0.030) and more patients required blood transfusion (p=0.020). In the MECC group, postoperative gas exchange values were better, intubation time shorter and lung injury score lower (p<0.001 for all comparisons). Our study suggests that MECC induces less coagulation disorders, leading to lower postoperative blood loss and better postoperative lung function. This approach may be advantageous in high-risk patients. © The Author(s) 2013

Polymer physics of chromosome large-scale 3D organisation

Chromosomes have a complex architecture in the cell nucleus, which serves vital functional purposes, yet its structure and folding mechanisms remain still incompletely understood. Here we show that genome-wide chromatin architecture data, as mapped by Hi-C methods across mammalian cell types and chromosomes, are well described by classical scaling concepts of polymer physics, from the sub-Mb to chromosomal scales. Chromatin is a complex mixture of di erent regions, folded in the conformational classes predicted by polymer thermodynamics. The contact matrix of the Sox9 locus, a region linked to severe human congenital diseases, is derived with high accuracy in mESCs and its molecular determinants identi ed by the theory; Sox9 self-assembles hierarchically in higher-order domains, involving abundant many-body contacts. Our approach is also applied to the Bmp7 locus. Finally, the model predictions on the e ects of mutations on folding are tested against available data on a deletion in the Xist locus. Our results can help progressing new diagnostic tools for diseases linked to chromatin misfolding

Early and long-term results of pectoralis muscle flap reconstruction vs sternal rewiring following failed sternal closure.

OBJECTIVES: The aim of the study was to compare early and long-term results of pectoralis muscle flap reconstruction with those of sternal rewiring following failed sternal closure. Primary outcomes of the study were survival and failure rate. Respiratory function, chronic pain and quality of life were also evaluated. METHODS: In a propensity-score matching analysis, of 94 patients who underwent sternal reconstruction, 40 were selected; 20 underwent sternal reconstruction with bilateral pectoralis muscle flaps (Group 1) and 20 underwent sternal rewiring (Group 2). Survival and failure rates were evaluated by in-hospital records and at follow-up. Respiratory function measures, including vital capacity (VC), were evaluated both by spirometry and computed tomography (CT) volumetry. Chronic pain was evaluated by the visual analogue pain scale. RESULTS: At 85 ± 24 months of follow-up, survival and procedure failure were 95 and 90% in Group 1 and 60 and 55% in Group 2, respectively (P < 0.01, for both comparisons). Based on CT-scan volumetry, in Group 1, severe non-union and hemisternal paradoxical movement occurred less frequently (2 vs 7, P = 0.01). At spirometry assessment, postoperative VC was greater in Group 1 (3220 ± 290 vs 3070 ± 290 ml, P = 0.04). The same trend was detected by CT-scan in-expiratory measures (4034 ± 1800 vs 3182 ± 862 mm3, P < 0.05). Correspondingly, in Group 1, less patients presented in NYHA Class III (P < 0.05), and both chronic persistent pain score and physical health quality-of-life score were significantly better in the same group. CONCLUSIONS: In our study, muscle flap reconstruction guaranteed better early and late-term results as shown by lower rates of mortality, procedure failure and hemisternum stability. Moreover, Group 1 patients had greater postoperative VC, lower NYHA class and better quality of life. These results suggest that, in patients with multiple bone fracture, the rewiring approach does not promote physiological bone consolidation, whereas the muscle flap reconstruction can assure more physiological ventilatory dynamics

Polymer physics indicates chromatin folding variability across single-cells results from state degeneracy in phase separation

The spatial organization of chromosomes has key functional roles, yet how chromosomes fold remains poorly understood at the single-molecule level. Here, we employ models of polymer physics to investigate DNA loci in human HCT116 and IMR90 wild-type and cohesin depleted cells. Model predictions on single-molecule structures are validated against single-cell imaging data, providing evidence that chromosomal architecture is controlled by a thermodynamics mechanism of polymer phase separation whereby chromatin self-assembles in segregated globules by combinatorial interactions of chromatin factors that include CTCF and cohesin. The thermodynamics degeneracy of single-molecule conformations results in broad structural and temporal variability of TAD-like contact patterns. Globules establish stable environments where specific contacts are highly favored over stochastic encounters. Cohesin depletion reverses phase separation into randomly folded states, erasing average interaction patterns. Overall, globule phase separation appears to be a robust yet reversible mechanism of chromatin organization where stochasticity and specificity coexist

Sex-dependent differences in left ventricular function and structure in chronic pressure overload

To evaluate gender-related differences in left ventricular (LV) structure and function in aortic stenosis, LV biplane cineangiography, micromanometry and endomyocardial biopsies were carried out in 56 patients with aortic stenosis and normal coronary arteries. Patients were divided into males (M: n= θ35), and females (F: n= θ21). Sixteen normal subjects 8 M, 8 F) served as haemodynamic controls. Control biopsy data were obtained from six pre-transplantation donor hearts (3 M and 3 F). LV systolic function was evaluated by ejection fraction and its relationship to mean systolic circumferential wall stress, diastolic function by the time constant of LV pressure decay, peak filling rates and passive myocardial stiffness constant. Biopsy samples were evaluated for interstitial fibrosis, muscle fibre diameter and volume fraction of myofibrils. In a subset of 27 consecutive patients, biopsy samples were evaluated with a morphometric-morphological method, for total collagen volume fraction, endocardial fibrosis and the extension and thickness of orthogonal collagen fibres (cross-hatching). In patients with aortic stenosis, aortic valve area, aortic valve resistance and mean aortic pressure gradient were comparable in males and females, whereas end-systolic and end-diastolic volumes were larger in males than females. Ejection fraction was lower (56%) in males than females (64%) (P 1.5 grade) was present in 11 males and four females with aortic stenosis (P<0.0I). An abnormal collagen architecture was present in 13114 males and 5113 females (V<0.002). In aortic stenosis, males have a depressed systolic function and abnormal passive elastic properties when compared to females with valve lesions of similar severity. Changes in collagen architecture may account, at least in part, for these difference

Effects of balloon injury on neointimal hyperplasia in steptozotocin-induced diabetes and in hyperinsulinemic nondiabetic pancreatic islet-transplanted rats.

BACKGROUND: The mechanisms of increased neointimal hyperplasia after coronary interventions in diabetic patients are still unknown. METHODS AND RESULTS: Glucose and insulin effects on in vitro vascular smooth muscle cell (VSMC) proliferation and migration were assessed. The effect of balloon injury on neointimal hyperplasia was studied in streptozotocin-induced diabetic rats with or without adjunct insulin therapy. To study the effect of balloon injury in nondiabetic rats with hyperinsulinemia, pancreatic islets were transplanted under the kidney capsule in normal rats. Glucose did not increase VSMC proliferation and migration in vitro. In contrast, insulin induced a significant increase in VSMC proliferation and migration in cell cultures. Furthermore, in VSMC culture, insulin increased MAPK activation. A reduction in neointimal hyperplasia was consistently documented after vascular injury in hyperglycemic streptozotocin-induced diabetic rats. Insulin therapy significantly increased neointimal hyperplasia in these rats. This effect of hyperinsulinemia was totally abolished by transfection on the arterial wall of the N17H-ras-negative mutant gene. Finally, after experimental balloon angioplasty in hyperinsulinemic nondiabetic islet-transplanted rats, a significant increase in neointimal hyperplasia was observed. CONCLUSIONS: In rats with streptozotocin-induced diabetes, balloon injury was not associated with an increase in neointimal formation. Exogenous insulin administration in diabetic rats and islet transplantation in nondiabetic rats increased both blood insulin levels and neointimal hyperplasia after balloon injury. Hyperinsulinemia through activation of the ras/MAPK pathway, rather than hyperglycemia per se, seems to be of crucial importance in determining the exaggerated neointimal hyperplasia after balloon angioplasty in diabetic animals

Heart rate, pr, and qt intervals in normal children: A 24‐hour holter monitoring study

A dynamic electrocardiographic Holter monitoring study was performed in 32 healthy children (20 males and 12 females, age range 6-11 years old), without heart disease, according to clinical and noninvasive instrumental examination. We evaluated atrioventricular conduction time (PR), heart rate (HR), and QT interval patterns defining the range of normality of these electrocardiographic parameters. The PR interval ranged from 154 +/- 10 ms (mean +/- SD) for HR less than or equal to 60 to 102 +/- 12 ms for HR greater than or equal to 120 (range 85-180). The absolute mean HR was 87 +/- 10 beats/min (range 72-104), the minimum observed HR being 61 +/- 10 (range 51-79), the maximum 160 +/- 20 beats/min (range 129-186). Daytime mean HR gave a mean value of 93 +/- 10 (range 71-148), while during night hours it was 74 +/- 11 (range 54-98). The minimum QT interval averaged 261 +/- 10 ms for HR greater than 120 and the maximum 389 +/- 9 ms for HR less than or equal to 60; the corresponding mean value of QTc (i.e., QT corrected for HR) ranged from 388 +/- 8 for HR less than or equal to 60 beats/min to 403 +/- 14 ms for HR greater than 120 beats/min. The results of the present study provide data of normal children which can be readily compared against those of subjects in whom cardiac abnormalities are suspect or patient.(ABSTRACT TRUNCATED AT 250 WORDS

Polymer models of chromatin organization

This is an invited commentary on the research field concerning the modelling of chromosome organization in the cell nucleus of eukaryotes

Alterations of autophagy in the peripheral neuropathy Charcot-Marie-Tooth type 2B

Charcot-Marie-Tooth type 2B (CMT2B) disease is a dominant axonal peripheral neuropathy caused by 5 mutations in the RAB7A gene, a ubiquitously expressed GTPase controlling late endocytic trafficking. In neurons, RAB7A also controls neuronal-specific processes such as NTF (neurotrophin) trafficking and signaling, neurite outgrowth and neuronal migration. Given the involvement of macroautophagy/autophagy in several neurodegenerative diseases and considering that RAB7A is fundamental for autophagosome maturation, we investigated whether CMT2B-causing mutants affect the ability of this gene to regulate autophagy. In HeLa cells, we observed a reduced localization of all CMT2B-causing RAB7A mutants on autophagic compartments. Furthermore, compared to expression of RAB7AWT, expression of these mutants caused a reduced autophagic flux, similar to what happens in cells expressing the dominant negative RAB7AT22N mutant. Consistently, both basal and starvation-induced autophagy were strongly inhibited in skin fibroblasts from a CMT2B patient carrying the RAB7AV162M mutation, suggesting that alteration of the autophagic flux could be responsible for neurodegeneration.Peer reviewe

Physical mechanisms of chromatin spatial organization

In higher eukaryotes, chromosomes have a complex three-dimensional (3D) conformation in the cell nucleus serving vital functional purposes, yet their folding principles remain poorly understood at the single-molecule level. Here, we summarize recent approaches from polymer physics to comprehend the physical mechanisms underlying chromatin architecture. In particular, we focus on two models that have been supported by recent, growing experimental evidence, the Loop Extrusion model and the Strings&Binders phase separation model. We discuss their key ingredients, how they compare to experimental data and some insight they provide on chromatin architecture and gene regulation. Progresses in that research field are opening the possibility to predict how genomic mutations alter the network of contacts between genes and their regulators and how that is linked to genetic diseases, such as congenital disorders and cancer