Massively Parallel Sequencing of Esophageal Brushings Enables an Aneuploidy-Based Classification of Patients With Barrett’s Esophagus

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Percutaneous coronary angioplasty in 1,001 multivessel coronary disease patients: an analysis of different patient subsets

The prospectively collected data of 1,001 multivessel coronary disease patients who underwent percutaneous transluminal angioplasty (PTCA) was analyzed after categorization into single vessel angioplasty (SVA; group I) and multiple vessel angioplasty (MVA; group II) PTCA groups, which were each compartmentalized into "simple" (group A) and "complex" (group B) cohorts. Patients were assigned to the SVA or MVA group according to the physician's pre-PTCA assessment of how many lesions would be attempted (intention to treat) and not the number of lesions actually attempted. A "simple" patient was more likely than a "complex" patient to be clinically improved after PTCA whether or not the patient had a single dilatation (90% vs 78%; P less than 0.05) or multiple dilatations (97% vs 94%; P<0.05). Similarly, a lesion(s) was more likely to be successfully dilated in the "simple" than in the "complex" group (SVA: 90% vs 82%, P less than 0.05; MVA: 97% vs 91%, P<0.05). In addition, occluded vessels in the MVA group were more likely to be recanalized than in the SVA group (73% vs 44%, P less than 0.05). Group I-A patients had a significantly increased (10%) incidence of emergency bypass surgery. Follow-up, at 84 months, showed that "simple" cohorts had a better survival than the "complex" cohorts (MVA: 95% vs 71%, P less than 0.05; SVA: 90% vs 72%, P less than 0.05); and, nearly two thirds of all successful PTCA patients were angina free.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of direct-acting oral anticoagulants (DOACs) on bleeding and blood product usage in cardiac surgery compared to warfarin and controls

In this retrospective, single-centre, observational study, we assessed (i) use of anticoagulant and antiplatelet (AP) therapy, (ii) the duration of direct-acting oral anticoagulant (DOAC) discontinuation, (iii) renal function and (iv) PT and APTT as predictors of bleeding and blood product usage; in adults (>18 years) undergoing major cardiac surgery from 01.01.2015 to 31.12.2018. Comparisons were made between each treatment group (warfarin, DOAC and DOAC + AP) and untreated controls, and between warfarin and DOAC. A total of 2928 patients were included for analysis. Median (range) of DOAC discontinuation prior to surgery was five days (1–22) for DOAC and five days (2–7) for DOAC + AP. There were no differences in bleeding between anticoagulant groups versus control, or DOAC versus warfarin. There were no differences in blood product use between DOAC and warfarin patients. The duration of DOAC discontinuation but not the creatinine clearance influenced bleeding and blood products use. Thrombosis occurred in 0·7% and 3·1% in controls and patients on warfarin respectively (P = 0·099) with none among patients on DOAC or DOAC + AP. The PT/APTT had no predictive value. Median five-day discontinuation of DOAC +/− AP irrespective of renal function prevents an increase in bleeding compared to patients on warfarin or controls with no increase in thrombosis.     

Apoptotic pore formation is associated with in-plane insertion of Bak or Bax central helices into the mitochondrial outer membrane

The pivotal step on the mitochondrial pathway to apoptosis is permeabilization of the mitochondrial outer membrane (MOM) by oligomers of the B-cell lymphoma-2 (Bcl-2) family members Bak or Bax. However, how they disrupt MOM integrity is unknown. A longstanding model is that activated Bak and Bax insert two α-helices, α5 and α6, as a hairpin across the MOM, but recent insights on the oligomer structures question this model. We have clarified how these helices contribute to MOM perforation by determining that, in the oligomers, Bak α5 (like Bax α5) remains part of the protein core and that a membrane-impermeable cysteine reagent can label cysteines placed at many positions in α5 and α6 of both Bak and Bax. The results are inconsistent with the hairpin insertion model but support an in-plane model in which α5 and α6 collapse onto the membrane and insert shallowly to drive formation of proteolipidic pores.Commitment of cells to apoptosis is determined primarily by interactions within the B-cell lymphoma-2 (Bcl-2) protein family on the mitochondrial outer membrane (MOM) (1–4). The proapoptotic members Bcl-2 antagonist/killer (Bak) and Bcl-2–associated X protein (Bax) mediate the pivotal step of MOM permeabilization, which releases proteins, such as cytochrome c, that promote the proteolytic demolition by caspases. Two other Bcl-2 subfamilies tightly control Bak and Bax activation. Their activation is promoted by the Bcl-2 homology domain 3 (BH3)-only proteins, such as BH3-interacting domain death agonist (Bid), the truncated form of which (tBid) can directly bind both. Conversely, prosurvival family members can bind and inhibit activated Bak and Bax, as well as the BH3-only proteins.Like their prosurvival relatives, Bak and Bax in healthy cells are globular monomers, comprising similar helical bundles with a hydrophobic α-helix (α5) surrounded by amphipathic helices (5, 6). Their C-terminal helix (α9) is a hydrophobic transmembrane (TM) domain that anchors them in the MOM. In healthy cells Bak is already anchored there, presumably solely by α9, whereas Bax is primarily cytosolic (5), accumulating at the MOM after an apoptotic signal and inserting its α9. Other major conformational changes in both Bak and Bax, reviewed in ref 4, include exposure of their BH3 (α2) and its reburial within the surface groove of another activated Bak or Bax molecule (7–10). These novel “symmetric” homo-dimers can multimerize via association of α6 helices (8, 11, 12).Although oligomeric Bak and Bax are highly implicated in MOM permeabilization, how they interact with the membrane to form pores remains a mystery. The first structure of a Bcl-2 family member, the prosurvival protein Bcl-x_L (13), and later those of Bax (5) and Bak (6), provided a tantalizing clue: similarities with the pore-forming domains of bacterial toxins, such as diphtheria toxin or colicin A. To form pores, these toxins are thought to insert their two hydrophobic core helices as a hairpin across the membrane (14), suggesting that the central helices of Bak and Bax (α5 and α6) might penetrate the MOM similarly (reviewed in refs 3, 15, and 16). Consistent with this hairpin insertion model, α5 and α6 peptides can permeabilize membranes (17–19). More pertinently, Bax α5 and α6 were reported to insert into and span the MOM as a hairpin before oligomerization (20).This longstanding model, however, does not fit well with recent evidence on the structure of Bak and Bax oligomers, as recently reviewed (2, 4). Analysis of Bak oligomers in liposomes by electron paramagnetic resonance (EPR) suggests that α6 inserts only shallowly in the lipid bilayer (21). Additionaly, the first 3D structures of activated forms of Bax (10) suggest that, early in its activation, α5 and α6 separate. Moreover, a Bax core domain containing only helices α2 to α5 generated a BH3:groove symmetric dimer in which two α4 and two α5 helices form an aromatic face that might sit on the bilayer (10). These findings fit better with an “in-plane model” in which only α9 is a TM domain and other helices (including α5 and α6) insert only shallowly into the bilayer.The nature of the apoptotic pores remains uncertain. Some findings favor a proteinaceous pore (22), but studies with model membranes suggest that Bax oligomers can perturb the bilayer and produce lipidic pores (i.e., pores not bounded entirely by protein) (23–26).These important unresolved questions about the pivotal event in apoptosis prompted us to explore the membrane topology of Bak, before, during, and after an apoptotic signal, and to reinvestigate that of Bax. In accord with recent Bax structures (10) and recent EPR studies on Bak (21, 27), the results show that neither oligomeric Bak nor Bax inserts an α5–α6 hairpin across the MOM. We propose instead that the α5 and α6 helices lie in the bilayer plane and disrupt membrane integrity by imposing tension and curvature to the membrane that provoke its permeabilization.     

Angiographic follow-up and clinical outcome of 126 patients after percutaneous directional atherectomy (Simpson AtheroCath) for occlusive peripheral vascular disease

Angiographic and clinical follow-up data were obtained in 115/126 patients who underwent directional atherectomy for peripheral vascular disease; of the 126, ten were excluded for appropriate reasons and one was lost to follow-up. Thus, 115/116 successful atherectomy patients (99%) had follow-up of 182/213 lesions (86%): 74 patients (64%) with angiography (mean time 5.4 mon), and 41 patients (36%) clinically. One hundred twenty-eight of 183 lesions (70%) had angiographic follow-up; the lesion recurrence as a stenosis or as an occlusion was 53%. Lesion distribution did not differ between angiography and clinical follow-up groups: nearly 85% were within the superficial femoral or popliteal arteries. Despite data stratification, angiographic follow-up indicated that patients after successful directional atherectomy, at a mean follow-up time of 5 mos, have more than a 50% lesion recurrence rate. Although directional atherectomy (Simpson AtheroCath) utilizing present techniques has excellent primary success and acceptable complication rates, angiographic follow-up statistics are bothersome.     

Comparison of screening for gestational diabetes mellitus by oral glucose tolerance tests done in the non-fasting (random) and fasting states

Aim

The Diabetes in Pregnancy Study Group of India (DIPSI) guidelines recommend the non-fasting 75-g oral glucose tolerance test (OGTT) as a single-step screening and diagnostic test for gestational diabetes mellitus (GDM). The aim of this study was to compare the DIPSI criteria with the World Health Organization (WHO) 1999 and the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria for GDM.

Methods

A total of 1,031 pregnant women attending antenatal clinics in urban and rural Tamil Nadu, India, underwent a 75-g OGTT in both non-fasting and fasting states, 2–3 days apart. Venous plasma glucose was measured using an autoanalyser, and GDM was diagnosed by DIPSI, WHO 1999 and IADPSG criteria.

Results

Of the 83 women identified to have GDM by WHO 1999 criteria, only 23 were diagnosed by DIPSI criteria. Of the 106 women diagnosed to have GDM by the IADPSG criteria, only 24 were diagnosed by DIPSI. The DIPSI non-fasting OGTT 2-h VPG cut point of 140 mg/dl (7.8 mmol/l) had a very low sensitivity when compared to the WHO 1999 criteria (sensitivity 27.7 %, specificity 97.7 %) and IADPSG criteria (sensitivity 22.6 %, specificity 97.8 %).

Conclusions

The DIPSI non-fasting OGTT criteria cannot be recommended for diagnosis of GDM due to its low sensitivity. Thus, as a single-step diagnostic test for GDM, the fasting OGTT needs to be done. When this is not possible, the well-established two-step procedure using the 50-g glucose challenge test as an initial screening test, followed by the diagnostic fasting OGTT, can be continued.     

Successful rotational coronary ablation following failed balloon angioplasty

Rotational coronary ablation was utilized in two cases in which balloon angioplasty initially failed. In both cases, the balloon could not be fully expanded despite using high (18 Bar) inflation pressure. Rotational coronary ablation debulked the lesion, in each instance, and permitted successful balloon angioplasty to be accomplished without difficulty. These cases illustrate the point that complementary deployment of devices may not only improve the primary success of percutaneous coronary interventions, but also may widen its scope.     

Angiographic follow-up and clinical outcome of 126 patients after percutaneous directional atherectomy (simpson atherocath™) for occlusive peripheral vascular disease

Angiographic and clinical follow-up data were obtained in 115/126 patients who underwent directional atherectomy for peripheral vascular disease; of the 126, ten were excluded for appropriate reasons and one was lost to follow-up. Thus, 115/116 successful atherectomy patients (99%) had follow-up of 182/213 lesions (86%): 74 patients (64%) with angiography (mean time 5.4 mon), and 41 patients (36%) clinically. One hundred twenty-eight of 183 lesions (70%) had angiographic follow-up; the lesion recurrence as a stenosis or as an occlusion was 53%. Lesion distribution did not differ between angiography and clinical follow-up groups: nearly 85% were within the superficial femoral or popliteal arteries. Despite data stratification, angiographic follow-up indicated that patients after successful directional atherectomy, at a mean follow-up time of >5 mos, have more than a 50% lesion recurrence rate. Although directional atherectomy (Simpson AtheroCath?) utilizing present techniques has excellent primary success and acceptable complication rates, angiographic follow-up statistics are bothersome.     

Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.