Bronchial and pulmonary arterial and venous interventions

With advancement of interventional techniques and increasing complexity of patients, the involvement of interventional radiologists in the pulmonary critical care (PCC) setting has increased in recent years. Particularly, interventional radiologists have evolved to play a significant role in treating patients with vascular pathologies such as massive pulmonary embolism. In this article, we discuss management of these critically ill patients using four pulmonary and bronchial vascular interventional procedures: bronchial artery embolization in the setting of hemoptysis; pulmonary artery embolization in the setting of the treatment of AVM; thrombectomy and thrombolysis of the pulmonary arteries for the treatment of pulmonary embolism; and catheter-directed stent placement in the treatment of superior vena cava syndrome.     

Incidence, predictors at admission, and impact of worsening renal function among patients hospitalized with heart failure

OBJECTIVES: The goal of this study was to determine the prevalence of worsening renal function (WRF) among hospitalized heart failure (HF) patients, clinical predictors of WRF, and hospital outcomes associated with WRF. BACKGROUND: Impaired renal function is associated with poor outcomes among chronic HF patients. METHODS: Chart reviews were performed on 1,004 consecutive patients admitted for a primary diagnosis of HF from 11 geographically diverse hospitals. Cox regression model analysis was used to identify independent predictors for WRF, defined as a rise in serum creatinine of >0.3 mg/dl (26.5 micromol/l). Bivariate analysis was used to determine associations of development of WRF with outcomes (in-hospital death, in-hospital complications, and length of stay). RESULTS: Among 1,004 HF patients studied, WRF developed in 27%. In the majority of cases, WRF occurred within three days of admission. History of HF or diabetes mellitus, admission creatinine > or =1.5 mg/dl (132.6 micromol/l), and systolic blood pressure >160 mm Hg were independently associated with higher risk of WRF. A point score based on these characteristics and their relative risk ratios predicted those at risk for WRF. Hospital deaths (adjusted risk ratio [ARR] 7.5; 95% confidence intervals [CI] 2.9, 19.3), complications (ARR 2.1; CI 1.5, 3.0), and length of hospitalizations >10 days (ARR 3.2, CI 2.2, 4.9) were greater among patients with WRF. CONCLUSIONS: Worsening renal function occurs frequently among hospitalized HF patients and is associated with significantly worse outcomes. Clinical characteristics available at hospital admission can be used to identify patients at increased risk for developing WRF.     

Comparison of biodegradable and newer generation durable polymer drug-eluting stents with short-term dual antiplatelet therapy: a systematic review and Bayesian network meta-analysis of randomized trials comprising of 43,875 patients

Journal of Thrombosis and Thrombolysis - Newer generation durable polymer drug-eluting stents (DP-DES) and biodegradable polymer DES (BP-DES) have similar efficacy with dual-antiplatelet therapy...     

Structure and stability of a second molten globule intermediate in the apomyoglobin folding pathway.

Apomyoglobin folding proceeds through a molten globule intermediate (low-salt form; I1) that has been characterized by equilibrium (pH 4) and kinetic (pH 6) folding experiments. Of the eight alpha-helices in myoglobin, three (A, G, and H) are structured in I1, while the rest appear to be unfolded. Here we report on the structure and stability of a second intermediate, the trichloroacetate form of the molten globule intermediate (I2), which is induced either from the acid-unfolded protein or from I1 by > or = 5 mM sodium trichloroacetate. Circular dichroism measurements monitoring urea- and acid-induced unfolding indicate that I2 is more highly structured and more stable than I1. Although I2 exhibits properties closer to those of the native protein, one-dimensional NMR spectra show that it maintains the lack of fixed side-chain structure that is the hallmark of a molten globule. Amide proton exchange and 1H-15N two-dimensional NMR experiments are used to identify the source of the extra helicity observed in I2. The results reveal that the existing A, G, and H helices present in I1 have become more stable in I2 and that a fourth helix--the B helix--has been incorporated into the molten globule. Available evidence is consistent with I2 being an on-pathway intermediate. The data support the view that apomyoglobin folds in a sequential fashion through a single pathway populated by intermediates of increasing structure and stability.     

Strain and screening effects on field emission properties of armchair graphene nanoribbon arrays: a first-principles study

The field screening effect on the field-emission properties of armchair graphene nanoribbons (AGNRs) under strain has been studied using first-principles calculations with local density approximation (LDA). Using the zone folding method with the effect of a dipole barrier along with the work function of strained graphene, we can obtain the work function of AGNR of any width under strain, confirmed with the LDA calculations. We have systematically investigated the effects of inter-ribbon distance and ribbon width on the work function of AGNR arrays. It is found that the work function of AGNR arrays increases rapidly as the inter-ribbon distance D_x increases, which is caused by the positive dipole at the edge of the ribbon. Using a simple linear interpolation model, we can obtain the work function of AGNRs of any ribbon-width and inter-ribbon distance. The dependences of the inter-ribbon distance and strain on the field enhancement factor have been determined. The enhancement factor reaches about 90% of its saturated value as the inter-ribbon distance approaches two times the ribbon-width. For a tensile strain, the field enhancement factor increases with applied strain while for a compressive one, the field enhancement factor is nearly independent. The effects of inter-ribbon distance and strain on the enhancement factor can be explained by the interlayer and intralayer screening effects, respectively.

The field screening effect on the field-emission properties of armchair graphene nanoribbons (AGNRs) under strain has been studied using first-principles calculations with local density approximation (LDA).     

The prognostic importance of different definitions of worsening renal function in congestive heart failure

BACKGROUND: Worsening renal function in patients hospitalized for heart failure portends a poor prognosis. However, criteria used to define worsening renal function are arbitrary, and the implications of different definitions remain unclear. We therefore compared the prognostic importance of various definitions of worsening renal function in 1,002 patients hospitalized for congestive heart failure (CHF). METHODS AND RESULTS: The patient population was 49% female, aged 67 +/- 15 years. Twenty-three percent had a prior history of renal failure, 73% had known depressed ejection fraction, and 63% had known CHF. On admission to the hospital, 47% were receiving ACE inhibitors, 22% beta-blockers, 70% diuretics and 6% NAID's. 72% developed increased serum creatinine during the hospitalization, with 20% developing an increase of > or = 0.5 mg/dL. Worsening renal function predicted both in-hospital mortality and length of stay > 10 days. Even an increased creatinine of 0.1 mg/dL was associated with worse outcome. Sensitivity for death decreased from 92% to 65% as the threshold for increased creatinine was raised from 0.1 to 0.5 mg/dL, with specificity increasing from 28% to 81%. At a threshold of a 0.3 mg/dL increase, sensitivity was 81% and specificity was 62% for death and 64% and 65% for length of stay >10 days. Adding a requirement of final creatinine of > or = 1.5 mg/dL improved specificity. CONCLUSIONS: This analysis demonstrates that any detectable decrease in renal function is associated with increased mortality and prolonged hospital stay. This suggests that therapeutic interventions which improve renal function might be beneficial.     

Reengineered salivary glands are stable endogenous bioreactors for systemic gene therapeutics

The use of critical-for-life organs (e.g., liver or lung) for systemic gene therapeutics can lead to serious safety concerns. To circumvent such issues, we have considered salivary glands (SGs) as an alternative gene therapeutics target tissue. Given the high secretory abilities of SGs, we hypothesized that administration of low doses of recombinant adeno-associated virus (AAV) vectors would allow for therapeutic levels of transgene-encoded secretory proteins in the bloodstream. We administered 10(9) particles of an AAV vector encoding human erythropoietin (hEPO) directly to individual mouse submandibular SGs. Serum hEPO reached maximum levels 8-12 weeks after gene delivery and remained relatively stable for 54 weeks (longest time studied). Hematocrit levels were similarly increased. Moreover, these effects proved to be vector dose-dependent, and even a dosage as low as 10(8) particles per animal led to significant increases in hEPO and hematocrit levels. Vector DNA was detected only within the targeted SGs, and levels of AAV copies within SGs were highly correlated with serum hEPO levels (r = 0.98). These results show that SGs appear to be promising targets with potential clinical applicability for systemic gene therapeutics.     

Effects of therapy with cholestyramine on progression of coronary arteriosclerosis: results of the NHLBI Type II Coronary Intervention Study

In the National Heart, Lung and Blood Institute Type II Coronary Intervention Study, patients with Type II hyperlipoproteinemia and coronary artery disease (CAD) were placed on a low-fat, low-cholesterol diet and then were randomly allocated to receive either 6 g cholestyramine four times daily or placebo. This double-blind study evaluated the effects of cholestyramine on the progression of CAD as assessed by angiography. Diet alone reduced the low-density lipoprotein cholesterol 6% in both groups. After randomization, low-density lipoprotein cholesterol decreased another 5% in the placebo group and 26% in the cholestyramine-treated group. Coronary angiography was performed in 116 patients before and after 5 years of treatment. CAD progressed in 49% (28 of 57) of the placebo-treated patients vs 32% (19 of 59) of the cholestyramine-treated patients (p less than .05). When only definite progression was considered, 35% (20 of 57) of the placebo-treated patients vs 25% (15 of 59) of the cholestyramine-treated patients exhibited definite progression; the difference was not statistically significant. However, when this analysis was performed with adjustment for baseline inequalities of risk factors, effect of treatment was more pronounced. Of lesions causing 50% or greater stenosis at baseline, 33% of placebo-treated and 12% of cholestyramine-treated patients manifested lesion progression (p less than .05). Similar analyses with other end points (percent of baseline lesions that progressed, lesions that progressed to occlusion, lesions that regressed, size of lesion change, and all cardiovascular end points) all favored the cholestyramine-treated group, but were not statistically significant. Thus, although the sample size does not allow a definitive conclusion to be drawn, this study suggests that cholestyramine treatment retards the rate of progression of CAD in patients with Type II hyperlipoproteinemia.