How bifurcation angle impacts the fate of side branch after main vessel stenting: a retrospective analysis of 1,200 consecutive bifurcation lesions in a single center

OBJECTIVES

We aimed to investigate the effect of bifurcation angle (BA) on side branch (SB) occlusion after main vessel (MV) stenting.

BACKGROUND

BA is thought to impact the risk of SB occlusion in coronary bifurcation patients undergoing percutaneous coronary intervention (PCI).

METHODS

A total of 1,171 consecutive patients with 1,200 bifurcation lesions undergoing one stent or provisional two stent techniques were studied. The lesions were divided into low angle and high angle groups using the median BA (52°). Multivariate logistic regression analysis was performed to identify independent predictors of SB occlusion.

RESULTS

SB occlusion occurred in 88 (7.33%) of 1,200 bifurcation lesions treated with the one stent technique or MV stenting first strategy. The rate of SB occlusion was significantly higher in the high angle group (63/600, 10.5%) than the low angle group (25/600, 4.2%) (P < 0.001). The rate of SB occlusion increased significantly across quartiles of BA as follows: from 3.63% in the first quartile of BA, to 4.71% in quartile II, to 8.14% in quartile III to 12.97% in quartile IV (P < 0.001). Multivariable analysis showed that high angle was an independent predictor of SB occlusion (odds ratio: 1.026, 95% confidence intervals: 1.014-1.037, P < 0.001). Plaque distribution at the same side of SB, MV Thrombolysis in Myocardial Infarction flow grade before stenting, pre-procedural diameter stenosis of bifurcation core, diameter ratio between MV/SB and diameter stenosis of SB before MV stenting were also independent predictors of SB occlusion.

CONCLUSIONS

High BA was an independent predictor of SB occlusion after MV stenting. The occlusion risk of SB with a high BA should not be ignored.

Analysis of underlying causes of inter-expert disagreement in retinopathy of prematurity diagnosis. Application of machine learning principles

OBJECTIVE

Inter-expert variability in image-based clinical diagnosis has been demonstrated in many diseases including retinopathy of prematurity (ROP), which is a disease affecting low birth weight infants and is a major cause of childhood blindness. In order to better understand the underlying causes of variability among experts, we propose a method to quantify the variability of expert decisions and analyze the relationship between expert diagnoses and features computed from the images. Identification of these features is relevant for development of computer-based decision support systems and educational systems in ROP, and these methods may be applicable to other diseases where inter-expert variability is observed.

METHODS

The experiments were carried out on a dataset of 34 retinal images, each with diagnoses provided independently by 22 experts. Analysis was performed using concepts of Mutual Information (MI) and Kernel Density Estimation. A large set of structural features (a total of 66) were extracted from retinal images. Feature selection was utilized to identify the most important features that correlated to actual clinical decisions by the 22 study experts. The best three features for each observer were selected by an exhaustive search on all possible feature subsets and considering joint MI as a relevance criterion. We also compared our results with the results of Cohen's Kappa [36] as an inter-rater reliability measure.

RESULTS

The results demonstrate that a group of observers (17 among 22) decide consistently with each other. Mean and second central moment of arteriolar tortuosity is among the reasons of disagreement between this group and the rest of the observers, meaning that the group of experts consider amount of tortuosity as well as the variation of tortuosity in the image.

CONCLUSION

Given a set of image-based features, the proposed analysis method can identify critical image-based features that lead to expert agreement and disagreement in diagnosis of ROP. Although tree-based features and various statistics such as central moment are not popular in the literature, our results suggest that they are important for diagnosis.

Reduced expression of regeneration associated genes in chronically axotomized facial motoneurons

Chronically axotomized motoneurons progressively fail to regenerate their axons. Since axonal regeneration is associated with the increased expression of tubulin, actin and GAP-43, we examined whether the regenerative failure is due to failure of chronically axotomized motoneurons to express and sustain the expression of these regeneration associated genes (RAGs). Chronically axotomized facial motoneurons were subjected to a second axotomy to mimic the clinical surgical procedure of refreshing the proximal nerve stump prior to nerve repair. Expression of α1-tubulin, actin and GAP-43 was analyzed in axotomized motoneurons using in situ hybridization followed by autoradiography and silver grain quantification. The expression of these RAGs by acutely axotomized motoneurons declined over several months. The chronically injured motoneurons responded to a refreshment axotomy with a re-increase in RAG expression. However, this response to a refreshment axotomy of chronically injured facial motoneurons was less than that seen in acutely axotomized facial motoneurons. These data demonstrate that the neuronal RAG expression can be induced by injury-related signals and does not require acute deprivation of target derived factors. The transient expression is consistent with a transient inflammatory response to the injury. We conclude that transient RAG expression in chronically axotomized motoneurons and the weak response of the chronically axotomized motoneurons to a refreshment axotomy provides a plausible explanation for the progressive decline in regenerative capacity of chronically axotomized motoneurons.

Comparison of procedural and long-term outcomes between transradial and transfemoral approach in one-stage intervention for triple vessel coronary artery disease

OBJECTIVES

The aim of the present study was to evaluate the safety, feasibility, procedural, and long-term outcomes by the transradial (TR) approach as compared to transfemoral (TF) approach in patients with triple vessel coronary artery disease undergoing one-stage percutaneous coronary intervention.

BACKGROUND

The feasibility, safety, and efficacy between the TR and TF approach for coronary interventional treatment have been compared in some complex situations including AMI and unprotected left main disease. However, in terms of triple vessel disease (3VD) intervention, there has been no comparison regarding procedural and long-term outcomes between the TR and TF approach.

METHODS

A total of 4,974 consecutive patients (TR n = 3,856, TF n = 1,118), who were diagnosed with 3VD without LM disease and underwent one-stage percutaneous revascularization, were enrolled in the study. Procedural results and clinical outcomes were obtained through database and follow-up. We used the propensity score matching method and obtained 930 pairs of patients with comparable baseline data in order to compare the procedural and long-term outcome between TR and TF groups. In the study cohort, risk reduction of all the clinical outcomes were evaluated with Cox's proportional-hazards models. Cumulative incidences concerning safety and efficacy of the cohort were estimated by the Kaplan-Meier method and a comparison was made utilizing the log-rank test.

RESULTS

After propensity score matching, the baseline clinical and angiographic characteristics were similar between the 2 groups. Regarding procedural results, no significant differences were observed between the 2 groups, with the exception of a decreased hospital stay (TR 7.49 ± 4.46 days vs. TF 8.63 ± 6.23 days, P < 0.0001) and fewer bleedings (TR 1.0% vs. TF 2.9, P = 0.003) in the TRI group. After an average 21-month follow-up, the all-cause mortality (TR 1.7% vs. TF 4.2%, P = 0.0014; HR 0.44, 0.25-0.79) was significantly lower with TRI patients. Other clinical outcomes were comparable between the 2 groups.

CONCLUSIONS

As compared to TFI, TRI for 3VD intervention is feasible, safe, and associated with similar procedural success, shorter hospitalization, reduced bleeding, lower incidence of death, and comparable long-term efficacy.

Melanocyte-specific CD8+ T cells are associated with epidermal depigmentation in a novel mouse model of vitiligo

In the present study, we established a novel murine model of vitiligo by sequential prime/boost immunizations into the hind footpad and tail dermis with tyrosinase-related protein 2 (TRP2)-180 (SVYDFFVWL) peptide, lipopolysaccharides and cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides. Immunized mice developed epidermal depigmentation in the tail skin without hair depigmentation, thereby differentiating this approach from established models of vitiligo. Following intradermal tail immunization, activated CD8(+) interferon (IFN)-γ(+) T cells were recruited locally to the tail skin. In-vivo cytotoxicity assays demonstrated specific lysis of TRP2-180-presenting cells in immunized mice. Furthermore, the extent of skin depigmentation correlated with the frequency of TRP2-180-specific splenic CD8(+) T cells, as determined by IFN-γ and tumour necrosis factor (TNF)-α production, and cytotoxic degranulation evidenced by CD107a staining. These findings suggest a correlation between the presence of TRP2-180-specific CD8(+) effector T cells and the development of depigmented skin lesions in our vitiligo model. This new model of vitiligo, characterized by skin depigmentation without hair depigmentation, is more similar to human disease than previous murine models. Therefore, this model is well suited to future studies on the pathogenesis of vitiligo and the development of novel therapeutics for vitiligo.

Forward osmosis with a novel thin-film inorganic membrane

Forward osmosis (FO) represents a new promising membrane technology for liquid separation driven by the osmotic pressure of aqueous solution. Organic polymeric FO membranes are subject to severe internal concentration polarization due to asymmetric membrane structure, and low stability due to inherent chemical composition. To address these limitations, this study focuses on the development of a new kind of thin-film inorganic (TFI) membrane made of microporous silica xerogels immobilized onto a stainless steel mesh (SSM) substrate. The FO performances of the TFI membrane were evaluated upon a lab-scale cell-type FO reactor using deionized water as feed solution and sodium chloride (NaCl) as draw solution. The results demonstrated that the TFI membrane could achieve transmembrane water flux of 60.3 L m(-2) h(-1) driven by 2.0 mol L(-1) NaCl draw solution at ambient temperature. Meanwhile, its specific solute flux, i.e. the solute flux normalized by the water flux (0.19 g L(-1)), was 58.7% lower than that obained for a commercial cellulose triacetate (CTA) membrane (0.46 g L(-1)). The quasi-symmetry thin-film microporous structure of the silica membrane is responsible for low-level internal concentration polarization, and thus enhanced water flux during FO process. Moreover, the TFI membrne demonstrated a substantially improved stability in terms of mechanical strength, and resistance to thermal and chemical stimulation. This study not only provides a new method for fabricating quasi-symmetry thin-film inorganic silica membrane, but also suggests an effective strategy using this alternative membrane to achieve improved FO performances for scale-up applications.

Delayed anti-CD3 therapy results in depletion of alloreactive T cells and the dominance of Foxp3+ CD4+ graft infiltrating cells

The engineered Fc-nonbinding (crystallizable fragment-nonbinding) CD3 antibody has lower mitogenicity and a precise therapeutic window for disease remission in patients with type 1 diabetes. Before anti-CD3 can be considered for use in transplantation, the most effective timing of treatment relative to transplantation needs to be elucidated. In this study anti-CD3F(ab')2 fragments or saline were administered intravenously for 5 consecutive days (early: d1-3 or delayed: d3-7) to mice transplanted with a cardiac allograft (H2(b)-to-H2(k); d0). Survival of allografts was prolonged in mice treated with the early protocol (MST = 48 days), but most were rejected by d100. In contrast, in mice treated with the delayed protocol allografts continued to survive long term. The delayed protocol significantly inhibited donor alloreactivity at d30 as compared to the early protocol. A marked increase in Foxp3(+) T cells (50.3 ± 1.6%) infiltrating the allografts in mice treated with the delayed protocol was observed (p < 0.0001 vs. early (24.9 ± 2.1%)) at d10; a finding that was maintained in the accepted cardiac allografts at d100. We conclude that the timing of treatment with anti-CD3 therapy is critical for inducing long-term graft survival. Delaying administration effectively inhibits the alloreactivity and promotes the dominance of intragraft Foxp3(+) T cells allowing long-term graft acceptance.

Induction of allograft tolerance by monoclonal CD3 antibodies: a matter of timing

Despite remarkable progress in organ transplantation through the development of a wealth of immunosuppressive drugs highly effective at controlling acute rejection, two major problems still remain, the loss of transplants due to chronic rejection and the growing number of sensitized recipients due to previous transplants, transfusions or pregnancies. Induction of immune tolerance appears to be the only way to curb this complex situation. Here we describe that a therapy, already successfully used to restore immune tolerance to self-antigens in overt autoimmunity, is effective at promoting transplant tolerance. We demonstrate that a short low-dose course with CD3 antibodies started after transplantation, at the time of effector T cell priming to alloantigens, induces permanent acceptance of fully mismatched islet allografts. Mechanistic studies revealed that antigen-specific regulatory and effector T cells are differentially affected by the treatment. CD3 antibody treatment preferentially induces apoptosis of activated alloreactive T cells which is mandatory for tolerance induction. In contrast, regulatory T cells are relatively spared from CD3 antibody-induced depletion and can transfer antigen-specific tolerance thus arguing for their prominent role in sustaining long-term graft survival.

OBSERVER AND FEATURE ANALYSIS ON DIAGNOSIS OF RETINOPATHY OF PREMATURITY

Retinopathy of prematurity (ROP) is a disease affecting low-birth weight infants and is a major cause of childhood blindness. However, human diagnoses is often subjective and qualitative. We propose a method to analyze the variability of expert decisions and the relationship between the expert diagnoses and features. The analysis is based on Mutual Information and Kernel Density Estimation on features. The experiments are carried out on a dataset of 34 retinal images diagnosed by 22 experts. The results show that a group of observers decide consistently with each other and there are popular features that have a high correlation with labels.

Principal curve based semi-automatic segmentation of organs in 3D-CT

Radiation therapy plays an important and effective role in the treatment of cancer. A main goal in radiation therapy is to deliver high radiation doses to the perceived tumors while minimizing radiation to surrounding normal tissues. Manual delineation of tumors and organs-at-risk(OARs) on three-dimensional computed tomography (3D-CT) is both a time-consuming and labor intensive task, and there maybe variability between manual delineations by different radiation oncologists. In this paper, we present a semi-supervised method to segment the contours of organs represented by piecewise linear segments connected with a small number of points given the user's input in one or more slices as an approximate initialization. This method detects ridge samples from the kernel interpolation of the edge map and approximates the shape of organs using piecewise linear segments among those sample points based on the principal curve score. Results are provided in two 3D-CT scans. Evaluation of the efficacy of our semiautomatic segmentation method is based on the overlapping ratio between the manually delineated contours and the semiautomatic segmented contours represented by a small number of points. The preserved points can be as low as 10 percent of the initial manual points, and the Dice Coefficients are approximately 0.93 for lung segmentation.

In vitro study of enhanced osteogenesis induced by HIF-1α-transduced bone marrow stem cells

OBJECTIVES

Hypoxia-inducible factor 1α (HIF-1α) is a pivotal regulator of hypoxic and ischaemic vascular responses that drives transcriptional activation of hundreds of genes involved in vascular reactivity, angiogenesis and arteriogenesis. Previous reports based on gene knockout technology have demonstrated that HIF-1α can promote osteogenesis. However, this protein is easily degraded in a normoxic state, which makes in vitro studies of HIF-1α-induced mesenchymal stem cell (MSC) osteogenesis difficult. For better understanding of HIF-1α promoting osteogenesis, the role of HIF-1α-induced MSC osteogenesis in the normoxic state has been investigated here.

MATERIALS AND METHODS

HIF-1α was made to overexpress using a lentiviral vector, and its effects on bone marrow-derived mesenchymal stem cell (BMSC) osteogenesis were investigated. Real-time quantitative and western blotting (to assess expression levels of angiogenic and osteogenic related genes regulated by Lenti-HIF-1α), alkaline phosphatase (ALP) and alizarin red-S staining analyses, were performed.

RESULTS

In HIF-1α gene-transfected BMSCs, expression levels of angiogenic, cartilaginous and osteogenic genes were all increased significantly compared to Lenti LacZ-transfected cells, at both mRNA and protein levels. ALP activity and alizarin red-S staining were significantly enhanced in HIF-1α transduced cells compared to control cells, on day 21.

CONCLUSIONS

These results indicate that Lenti-HIF-1α can induce BMSC overexpression levels of angiogenic and osteogenic genes in vitro in the normoxic state. Further study will be focused on whether HIF-1α can also improve bone repair in vivo.

Bioaugmentation of a biological contact oxidation ditch with indigenous nitrifying bacteria for in situ remediation of nitrogen-rich stream water

In this study, specialized bacteria were domesticated and cultivated with polluted stream water. The bioaugmentation of specialized bacteria would significantly enhance the removal efficiency of TN and NH4+-N from 25.9% to 50.3%, and from 34.5% to 60.1%, respectively. Concomitant increases in the number of microbial communities and the proportion of nitrifying bacteria were also identified by the most probable number (MPN) method. PCR-DGGE profiles revealed that the bacterial community could be successfully enriched and the ammonia-oxidizing bacteria communities were shown predominant by the species of Nitrosomonas. The biological contact oxidation ditch (BCOD) system augmented with specialized bacteria can be a viable alternative for treating polluted stream water to achieve improved nitrogen removal.

Extraction of samples from airway and vessel trees in 3D lung CT based on a multi-scale principal curve tracing algorithm

The extraction of airway and vessel trees plays an important role in the diagnosis and treatment planning of lung diseases. However, this is a challenging task due to the small size of the anatomical structures, noise, or artifacts in the image. The similar intensity values between the lung parenchyma and airway lumen, the airway wall and the blood vessels make extraction particularly difficult. Our method detailed herein presents an automatic extraction of samples of both the airways and vessels from the three-dimensional computed tomography (3D-CT) based on the multi-scale principal curve algorithm. The image is first thresholded to find airway or vessel candidates according to their corresponding Hounsfield units (HU). The Frangi filter is then used to extract the tubular structures and remove background noise. Finally, a multi-scale principal curve projection and tracing algorithm is applied on the filtered image to identify the centerlines of the airway and vessel trees.

Follow-up by cardiac magnetic resonance imaging in patients with hypertrophic cardiomyopathy who underwent percutaneous ventricular septal ablation

To evaluate myocardial infarction and describe the early to mid-term changes induced by percutaneous ventricular septal ablation (PVSA) in symptomatic patients with hypertrophic cardiomyopathy using cardiac magnetic resonance imaging. Cardiac magnetic resonance imaging was performed before and 1 week and 1 year after PVSA in 52 patients. The relation between the infarction size and other factors was determined. At 1 week after PVSA, regional hyperenhancement was visualized in the basal interventricular septum in all patients. The mean infarction size was 29.5 ± 15.9 g. The infarction size correlated well with the ethanol volume. The left ventricular myocardial mass decreased significantly from 196.1 ± 65.9 g at baseline to 183.4 ± 63.6 g 1 week after PVSA (p <0.001) and 164.1 ± 60.9 g within the 1-year follow-up period (p <0.001). In conclusion, cardiac magnetic resonance imaging allowed a detailed evaluation of the size and location of septal myocardial infarction induced by PVSA. The left ventricular myocardial mass decreased significantly during the follow-up period.