A comprehensive assessment of environmental exposures and the medical history guides multidisciplinary discussion in interstitial lung disease.

BACKGROUND: Multidisciplinary discussion (MDD) is widely recommended for patients with interstitial lung disease (ILD), but published primary data from MDD has been scarce, and factors influencing MDD other than chest computed tomography (CT) and lung histopathology interpretations have not been well-described. METHODS: Single institution MDD of 179 patients with ILD. RESULTS: MDD consensus clinical diagnoses included autoimmune-related ILD, chronic hypersensitivity pneumonitis, smoking-related ILD, idiopathic pulmonary fibrosis, medication-induced ILD, occupation-related ILD, unclassifiable ILD, and a few less common pulmonary disorders. In 168 of 179 patients, one or more environmental exposures or pertinent features of the medical history were identified, including recreational/avocational, residential, and occupational exposures, systemic autoimmune disease, malignancy, medication use, and family history. The MDD process demonstrated the importance of comprehensively assessing these exposures and features, beyond merely noting their presence, for rendering consensus clinical diagnoses. Precise, well-defined chest CT and lung histopathology interpretations were rendered at MDD, including usual interstitial pneumonia, nonspecific interstitial pneumonia, and organizing pneumonia, but these interpretations were associated with a variety of MDD consensus clinical diagnoses, demonstrating their nonspecific nature in many instances. In 77 patients in which MDD consensus diagnosis differed from referring diagnosis, assessment of environmental exposures and medical history was found retrospectively to be the most impactful factor. CONCLUSIONS: A comprehensive assessment of environmental exposures and pertinent features of the medical history guided MDD. In addition to rendering consensus clinical diagnoses, MDD presented clinicians with opportunities to initiate environmental remediation, behavior modification, or medication alteration likely to benefit individual patients with ILD.

Fluorescent enzyme-coupled activity assay for phenylalanine ammonia-lyases.

Phenylalanine ammonia-lyases (PALs) catalyse the non-oxidative deamination of L-phenylalanine to trans-cinnamic acid, while in the presence of high ammonia concentration the reverse reaction occurs. PALs have been intensively studied, however, their industrial applications for amino acids synthesis remained limited, mainly due to their decreased operational stability or limited substrate specificity. The application of extensive directed evolution procedures to improve their stability, activity or selectivity, is hindered by the lack of reliable activity assays allowing facile screening of PAL-activity within large-sized mutant libraries. Herein, we describe the development of an enzyme-coupled fluorescent assay applicable for PAL-activity screens at whole cell level, involving decarboxylation of trans-cinnamic acid (the product of the PAL reaction) by ferulic acid decarboxylase (FDC1) and a photochemical reaction of the produced styrene with a diaryltetrazole, that generates a detectable, fluorescent pyrazoline product. The general applicability of the fluorescent assay for PALs of different origin, as well as its versatility for the detection of tyrosine ammonia-lyase (TAL) activity have been also demonstrated. Accordingly, the developed procedure provides a facile tool for the efficient activity screens of large mutant libraries of PALs in presence of non-natural substrates of interest, being essential for the substrate-specificity modifications/tailoring of PALs through directed evolution-based protein engineering.

A Survey of Academic Intensivists' Use of Neuromuscular Blockade in Subjects With ARDS.

BACKGROUND: Our Cooling to Help Injured Lungs (CHILL) trial of therapeutic hypothermia in ARDS includes neuromuscular blockade (NMB) as an inclusion criterion to avoid shivering. NMB has been used to facilitate mechanical ventilation in ARDS and was shown to reduce mortality in the ACURASYS trial. To assess the feasibility of a multi-center CHILL trial, we conducted a survey of academic intensivists about their NMB use in patients with ARDS. METHODS: We distributed via email a 16-question survey about NMB use in patients with ARDS including frequency, indications, and dosing strategy. RESULTS: 212 (24.3%) of 871 respondents completed the survey: 94.7% were board-certified in internal medicine, 88% in pulmonary and critical care; 90.3% practiced in academic medical centers, with 87% working in medical ICUs; 96.6% of respondents who treat ARDS use NMB, and 39.7% use NMB in ≥ 50% of these patients. Of 4 listed indications for initiating NMB in ARDS, allowing adherence with lung-protective ventilator strategies and patient-ventilator synchrony were cited as the most important reasons, followed by the results of the ACURASYS trial and facilitating prone positioning. CONCLUSIONS: We conclude that NMB is frequently used by academic intensivists to facilitate mechanical ventilation in patients with moderate to severe ARDS.

Combined Pulmonary Fibrosis and Emphysema: Pulmonary Function Testing and a Pathophysiology Perspective.

Combined pulmonary fibrosis and emphysema (CPFE) has been increasingly recognized over the past 10-15 years as a clinical entity characterized by rather severe imaging and gas exchange abnormalities, but often only mild impairment in spirometric and lung volume indices. In this review, we explore the gas exchange and mechanical pathophysiologic abnormalities of pulmonary emphysema, pulmonary fibrosis, and combined emphysema and fibrosis with the goal of understanding how individual pathophysiologic observations in emphysema and fibrosis alone may impact clinical observations on pulmonary function testing (PFT) patterns in patients with CPFE. Lung elastance and lung compliance in patients with CPFE are likely intermediate between those of patients with emphysema and fibrosis alone, suggesting a counter-balancing effect of each individual process. The outcome of combined emphysema and fibrosis results in higher lung volumes overall on PFTs compared to patients with pulmonary fibrosis alone, and the forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio in CPFE patients is generally preserved despite the presence of emphysema on chest computed tomography (CT) imaging. Conversely, there appears to be an additive deleterious effect on gas exchange properties of the lungs, reflecting a loss of normally functioning alveolar capillary units and effective surface area available for gas exchange, and manifested by a uniformly observed severe reduction in the diffusing capacity for carbon monoxide (DLCO). Despite normal or only mildly impaired spirometric and lung volume indices, patients with CPFE are often severely functionally impaired with an overall rather poor prognosis. As chest CT imaging continues to be a frequent imaging modality in patients with cardiopulmonary disease, we expect that patients with a combination of pulmonary emphysema and pulmonary fibrosis will continue to be observed. Understanding the pathophysiology of this combined process and the abnormalities that manifest on PFT testing will likely be helpful to clinicians involved with the care of patients with CPFE.

Intrapleural Alteplase and Dornase in a Pregnant Woman With Complicated Parapneumonic Effusion.

The use of intrapleural alteplase and dornase in pregnant patients remains an uncertain practice because bleeding complications in these cases could be devastating. We present a case in which we successfully used a modified protocol safely.

The role of statins in chronic obstructive pulmonary disease: is cardiovascular disease the common denominator?

PURPOSE OF REVIEW: The pleiotropic anti-inflammatory effects of statins that have proven to improve outcomes in cardiovascular disease have also been of interest in the treatment of COPD, a disease with considerable morbidity and little available treatment that improves mortality. In-vitro and animal studies have supported biologic plausibility of statin therapy for lung health and function. Retrospective observational studies in humans have echoed this potential as well but confirmatory data from randomized studies are limited and somewhat disappointing. RECENT FINDINGS: Despite discouraging clinical trial results, the possibility remains that statins can help patients with COPD characterized by systemic inflammation. At the same time, increasing recognition of the considerable cardiovascular disease burden and its suboptimal treatment in patients with COPD has also contributed to continued enthusiasm for statin use in COPD. SUMMARY: When it comes to defining the role for statins as a disease-modifying therapy, the jury is still out; however, the importance of more careful cardiovascular risk stratification that includes assessing levels of inflammatory markers in patients with COPD and the benefit of statins in those with increased risk is gaining increasing recognition.

Troubleshooting a dialysis line: when blue runs red.

We present the case of a critically ill woman whose dialysis line was noted to be circulating bright red blood. Located in the right internal jugular vein, the line had previously been working normally with the change occurring shortly after the patient was liberated from positive pressure mechanical ventilation. An arterial malposition was ruled out and subsequent investigations revealed the presence of a left-sided partial anomalous pulmonary venous connection (PAPVC) that had been previously undiagnosed. The identification of a left-sided PAPVC from blood gas measurements taken from a right internal jugular vein dialysis catheter in this case provides an informative opportunity to consider the intricate physiological relationship between the respiratory and cardiovascular systems in critically ill patients requiring invasive procedures and treatments.

The high affinity of small-molecule antioxidants for hemoglobin.

Hemoglobin has previously been shown to display ascorbate peroxidase and urate peroxidase activity, with measurable Michaelis-Menten parameters that reveal a particularly low Km for ascorbate as well as for urate - lower than the respective in vivo concentrations of these antioxidants in blood. Also, direct detection of a hemoglobin-ascorbate interaction was possible by monitoring the 1H-NMR spectrum of ascorbate in the presence of hemoglobin. The relative difference in structures between ascorbate and urate may raise the question as to exactly what the defining structural features would be, for a substrate that binds to hemoglobin with high affinity. Reported here are Michaelis-Menten parameters for hemoglobin acting as peroxidase against a number of other substrates of varying structures - gallate, caffeate, rutin, 3-hydroxyflavone, 3,6-dihydroxyflavone, quercetin, epicatechin, luteolin - all with high affinities (some higher than those of physiologically-relevant redox partners of Hb - ascorbate and urate). Moreover, this high affinity appears general to animal hemoglobins. 1H-NMR and 13C-NMR spectra reveal a general pattern wherein small hydrophilic antioxidants appear to all have their signals affected, presumably due to binding to hemoglobin. Fluorescence and calorimetry measurements confirm these conclusions. Docking calculations confirm the existence of binding sites on hemoglobin and on myoglobin for ascorbate as well as for other antioxidants. Support is found for involvement of Tyr42 in binding of three out of the four substrates investigated in the case of hemoglobin (including ascorbate and urate, as blood-contained relevant substrates), but also for Tyr145 (with urate and caffeate) and Tyr35 (with gallate).

Intravenous Immunoglobulin as Potential Adjunct Therapy for Interstitial Lung Disease.

Intravenous Ig (IVIg) is a pooled plasma product consisting primarily of monomeric IgG. For the past several decades, the use of IVIg has expanded to include the treatment of various autoimmune and inflammatory disorders, including Kawasaki's disease, antineutrophil cytoplasmic antibody-associated vasculitis, systemic lupus erythematosis, and the inflammatory myopathies. IVIg is thought to exert its immunomodulatory effects through a variety of mechanisms: neutralization of pathogenic autoantibodies; alteration of immune cell effector function; suppression of cytokine and chemokine activity; and interference with complement activation. Interstitial lung disease (ILD) is a frequent complication of autoimmune disorders and connective tissue diseases, and the presence of ILD is associated with significant morbidity and mortality. Although there are currently no large studies to support the use of IVIg in the treatment of ILD, it is being used off-label with increasing frequency for refractory cases that have failed to respond to standard immunosuppression. Although associated with less systemic toxicity and global immunosuppression than traditional agents, IVIg is much more costly. Therefore, although the routine use of IVIg to treat ILD is not currently recommended, future studies to determine its role in pulmonary disease are warranted.

Treating orthostatic hypotension in patients with Parkinson's disease and atypical Parkinsonism improves function.

BACKGROUND: Patients with idiopathic Parkinson's disease (PD) or atypical Parkinsonism (AP) often present with orthostatic hypotension (OH) as a result of the dysautonomia associated with the disease or as a side effect of the dopaminergic medications used to treat it. Our recent study suggested that OH negatively impacts gross motor, balance, and cognitive functions in patients with PD. OBJECTIVE: To determine if correcting the orthostatic hypotension (OH) of patients with PD or AP improves their gross motor, balance, and cognitive functions. METHODS: Forty patients with PD or AP were assessed before and after correcting their OH using a staged approach with a goal of SBP >80 when standing and SBP <180 when laying. Step 1 of treatment included reducing antihypertensive medications, as possible, maintaining hydration with 1500cc/day, decreasing dietary salt, wearing high compression stockings, and keeping the head of bed elevated at 30 degrees when supine. If SBP <80 with standing after step 1, then treatment was started with fludrocortisone and/or midodrine. RESULTS: Patients' OH was managed as part of a rehabilitation program. Tests such as the Motor and Cognitive Functional Independence Measures, Berg Balance Scale, Two Minute Walking test, and the Finger Tapping test showed significant improvements (p < 0.05) in their gross motor, walking, balance and cognitive function with our OH management plan. No significant differences between admission and discharge were found in the Timed Up and Go test. CONCLUSION: Our data suggest that monitoring and correcting the OH of patients with PD or AP improves their gross motor, balance, and cognitive function.

Kinetic analysis of GTP hydrolysis catalysed by the Arf1-GTP-ASAP1 complex.

Arf (ADP-ribosylation factor) GAPs (GTPase-activating proteins) are enzymes that catalyse the hydrolysis of GTP bound to the small GTP-binding protein Arf. They have also been proposed to function as Arf effectors and oncogenes. We have set out to characterize the kinetics of the GAP-induced GTP hydrolysis using a truncated form of ASAP1 [Arf GAP with SH3 (Src homology 3) domain, ankyrin repeats and PH (pleckstrin homology) domains 1] as a model. We found that ASAP1 used Arf1-GTP as a substrate with a k(cat) of 57+/-5 s(-1) and a K(m) of 2.2+/-0.5 microM determined by steady-state kinetics and a kcat of 56+/-7 s(-1) determined by single-turnover kinetics. Tetrafluoroaluminate (AlF4-), which stabilizes complexes of other Ras family members with their cognate GAPs, also stabilized a complex of Arf1-GDP with ASAP1. As anticipated, mutation of Arg-497 to a lysine residue affected kcat to a much greater extent than K(m). Changing Trp-479, Iso-490, Arg-505, Leu-511 or Asp-512 was predicted, based on previous studies, to affect affinity for Arf1-GTP. Instead, these mutations primarily affected the k(cat). Mutants that lacked activity in vitro similarly lacked activity in an in vivo assay of ASAP1 function, the inhibition of dorsal ruffle formation. Our results support the conclusion that the Arf GAP ASAP1 functions in binary complex with Arf1-GTP to induce a transition state towards GTP hydrolysis. The results have led us to speculate that Arf1-GTP-ASAP1 undergoes a significant conformational change when transitioning from the ground to catalytically active state. The ramifications for the putative effector function of ASAP1 are discussed.