Breeding strategies for late blight resistance in potato crop: recent developments.

Late blight (LB) is a serious disease that affects potato crop and is caused by Phytophthora infestans. Fungicides are commonly used to manage this disease, but this practice has led to the development of resistant strains and it also poses serious environmental and health risks. Therefore, breeding for resistance development can be the most effective strategies to control late blight. Various Solanum species have been utilized as a source of resistance genes to combat late blight disease. Several potential resistance genes and quantitative resistance loci (QRLs) have been identified and mapped through the application of molecular techniques. Furthermore, molecular markers closely linked to resistance genes or QRLs have been utilized to hasten the breeding process. However, the use of single-gene resistance can lead to the breakdown of resistance within a short period. To address this, breeding programs are now being focused on development of durable and broad-spectrum resistant cultivars by combining multiple resistant genes and QRLs using advanced molecular breeding tools such as marker-assisted selection (MAS) and cis-genic approaches. In addition to the strategies mentioned earlier, somatic hybridization has been utilized for the development and characterization of interspecific somatic hybrids. To further broaden the scope of late blight resistance breeding, approaches such as genomic selection, RNAi silencing, and various genome editing techniques can be employed. This study provides an overview of recent advances in various breeding strategies and their applications in improving the late blight resistance breeding program.

Genetic diversity and interrelationship among Indian and exotic melons based on fruit morphology, quality components and microsatellite markers.

Seventy melon (Cucumis melo L.) accessions comprising of landraces, inbred lines, cultivars, wild relatives and exotic populations were characterized using fifteen fruit traits and 30 SSR markers. Overall, aim of this study was to investigate the genetic relatedness across origins, horticultural groups and accession categories. Significant differences were observed for days to first fruit maturity, fruit weight, fruits per vine, yield per plant, flesh thickness, fruit shape index, total soluble solids, ß-carotene, ascorbic acid and titrable acidity. Twenty-four polymorphic SSRs detected 67 distinct alleles with moderate polymorphic information content (0.43) and genetic diversity (0.44). Observed heterozygosity (0.53) was higher than expected heterozygosity (0.48) which can be attributed to out-cross nature of melons. Neighbor joining tree based on SSRs diverged 70 accessions into six clusters independent of geographic sites of collections. Momordica and inodorus accessions formed distinct clusters, with some exceptions. Intermixing of landraces, modern cultivars and exotic accessions belonging to different taxa and geographic regions indicated genetic resemblance with each other. Hybridization among exotic and indigenous genetic resources can be utilized for genetic enhancement and introgression of new traits in modern melon cultivars.

In vitro induction and selection of mutants obtained through gamma irradiation with improved processing traits in potato (Solanum tuberosum L.).

PURPOSE: This manuscript aimed for the generation of γ-irradiation derived mutants of potato genotype PAU/RR-1501 possessing desirable processing traits. MATERIALS AND METHODS: Nodal cuttings from virus-free explants were established on basal MS medium and irradiated with different doses (0, 5, 10 and 20 Gy) of γ-irradiation. The 5 and 10 Gy treated plantlets were multiplied and used for micro-tuber induction. Harvested micro-tubers were planted in pots for the selection and evaluation of mutants in M1V2 generation. RESULTS: Four weeks post-treatment, plantlets (5 Gy) showed enhanced growth as compared to the control while 20 Gy treatment exhibited completely ceased shoot growth. The highest number and weight of mini-tubers per plant was recorded for 10 Gy followed by 5 Gy treatment as compared to control. The γ-irradiation treatments caused changes in the skin color and shape of M1V2 tubers. CONCLUSION: Under the 5 Gy treatment 49.9% of clones produced exhibited cream and 8.53% brown skin color. Nine putative mutants were identified in genotype PAU/RR-1501 exhibiting promising processing traits.

In-Silico Identification, Characterization and Expression Analysis of Genes Involved in Resistant Starch Biosynthesis in Potato (Solanum tuberosum L.) Varieties.

Potato (Solanum tuberosum L.), an important horticultural crop is a member of the family Solanaceae and is mainly grown for consumption at global level. Starch, the principal component of tubers, is one of the significant elements for food and non-food-based applications. The genes associated with biosynthesis of starch have been investigated extensively over the last few decades. However, a complete regulation pathway of constituent of amylose and amylopectin are still not deeply explored. The current in-silico study of genes related to amylose and amylopectin synthesis and their genomic organization in potato is still lacking. In the current study, the nucleotide and amino acid arrangement in genome and twenty-two genes linked to starch biosynthesis pathway in potato were analysed. The genomic structure analysis was also performed to find out the structural pattern and phylogenetic relationship of genes. The genome mining and structure analysis identified ten specific motifs and phylogenetic analysis of starch biosynthesis genes divided them into three different clades on the basis of their functioning and phylogeny. Quantitative real-time PCR (qRT-PCR) of amylose biosynthesis pathway genes in three contrast genotypes revealed the down-gene expression that leads to identify potential cultivar for functional genomic approaches. These potential lines may help to achieve higher content of resistant starch.

The impact of repeated marathon running on cardiovascular function in the aging population.

BACKGROUND: Several studies have correlated elevations in cardiac biomarkers of injury post marathon with transient and reversible right ventricular (RV) systolic dysfunction as assessed by both transthoracic echocardiography (TTE) and cardiovascular magnetic resonance (CMR). Whether or not permanent myocardial injury occurs due to repeated marathon running in the aging population remains controversial. OBJECTIVES: To assess the extent and severity of cardiac dysfunction after the completion of full marathon running in individuals greater than 50 years of age using cardiac biomarkers, TTE, cardiac computed tomography (CCT), and CMR. METHODS: A total of 25 healthy volunteers (21 males, 55 ± 4 years old) from the 2010 and 2011 Manitoba Full Marathons (26.2 miles) were included in the study. Cardiac biomarkers and TTE were performed one week prior to the marathon, immediately after completing the race and at one-week follow-up. CMR was performed at baseline and within 24 hours of completion of the marathon, followed by CCT within 3 months of the marathon. RESULTS: All participants demonstrated an elevated cTnT post marathon. Right atrial and ventricular volumes increased, while RV systolic function decreased significantly immediately post marathon, returning to baseline values one week later. Of the entire study population, only two individuals demonstrated late gadolinium enhancement of the subendocardium in the anterior wall of the left ventricle, with evidence of stenosis of the left anterior descending artery on CCT. CONCLUSIONS: Marathon running in individuals over the age of 50 is associated with a transient, yet reversible increase in cardiac biomarkers and RV systolic dysfunction. The presence of myocardial fibrosis in older marathon athletes is infrequent, but when present, may be due to underlying occult coronary artery disease.

Multi-Wall Carbon Nanotubes, Metal Oxide and Hydroxy-Apatite Nanoparticles Enhanced Plant Growth Promoting Capabilities of Root Endosymbionts of Cowpea (Vigna unguiculata (L.) Walp.).

The present study was aimed to evaluate the effect of three different nanomaterials (NMs) on the growth, physiology and protein profile of the endosymbiotic bacteria isolated from the root nodules of vegetable cowpea. The alterations in growth and viability of the bacterial cells, their indole-acetic acid (IAA) and siderophore production abilities, phosphate solubilization potential and total protein content were assessed. Further, the isolates were also analyzed for changes in their exopolysaccharide (EPS) production and secretion behavior with exposure to different concentrations of the NMs. The NM supplementation of the broth improved the growth, viable cell count, IAA content, siderophore production and potential to solubilize tri-calcium phosphate (TCP) as sole phosphorus (P)-source. The NMs also improved the total protein content of the bacterial cells indicating the improved physiology and biochemistry of the treated bacterial cells. The treated cells produced significantly high EPS compared to untreated control cultures. The present investigation revealed that the NMs improved plant growth abilities of cowpea root endosymbiotic bacteria, though the impact varied across various isolates as well as NM concentrations.

Chitosan-Urea Nanocomposite for Improved Fertilizer Applications: The Effect on the Soil Enzymatic Activities and Microflora Dynamics in N Cycle of Potatoes (Solanum tuberosum L.).

The impact of polymer-based slow-release urea formulations on soil microbial N dynamics in potatoes has been sparingly deciphered. The present study investigated the effect of a biodegradable nano-polymer urea formulation on soil enzymatic activities and microflora involved in the N cycling of potato (Solanum tuberosum L.). The nano-chitosan-urea composite (NCUC) treatment significantly increased the soil dehydrogenase activity, organic carbon content and available potassium compared to the conventional urea (CU) treatment. The soil ammonical nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) contents and urease activity were significantly decreased in the NCUC-amended soil. The slow urea hydrolysis rate led to low concentrations of NH4+-N and NO3--N in the tested potato soil. Furthermore, these results corroborate the low count of ammonia oxidizer and nitrate reducer populations. Quantitative PCR (q-PCR) studies revealed that the relative abundance of eubacterial (AOB) and archaeal ammonia-oxidizing (AOA) populations was reduced in the NCUC-treated soil compared to CU. The abundance of AOA was particularly lower than AOB, probably due to the more neutral and alkaline conditions of the tested soil. Our results suggest that the biodegradable polymer urea composite had a significant effect on the microbiota associated with soil N dynamics. Therefore, the developed NCUC could be used as a slow N-release fertilizer for enhanced growth and crop yields of potato.

Cardiac imaging in myocardial sarcoidosis and other cardiomyopathies.

PURPOSE OF REVIEW: The clinical role of emerging imaging technologies for diagnosing cardiac sarcoidosis and other cardiomyopathies is evolving. An up-to-date review of the role of various imaging modalities in the evaluation of cardiac sarcoidosis and other cardiomyopathies is presented. RECENT FINDINGS: No study prospectively established the accuracy of each of the various techniques for diagnosing myocardial involvement in patients with suspected cardiac sarcoidosis. Cardiac magnetic resonance imaging (CMR) is demonstrated to have a sensitivity of 100% and specificity of approximately 80%, and positive predictive value of approximately 55% in diagnosing cardiac sarcoidosis. Recent studies have shown that 18F-2-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) has 100% sensitivity of detecting earlier stages of sarcoidosis. Both the FDG-PET and CMR may provide complementary information for the diagnosis and assessment of efficacy of therapy in patients with cardiac involvement from sarcoidosis. SUMMARY: Clinical and subclinical cardiac involvement is common among patients with sarcoidosis. A structured clinical assessment incorporating advanced cardiac imaging with CMR and FDG-PET scanning is more sensitive than the established clinical criteria. CMR is an established imaging modality in the diagnosis of various other cardiomyopathies. Well designed prospective clinical trials are awaited to define the exact role of these imaging studies in the diagnosis and guidance of therapy.

Critically ill patients with 2009 influenza A(H1N1) infection in Canada.

CONTEXT: Between March and July 2009, the largest number of confirmed cases of 2009 influenza A(H1N1) infection occurred in North America. OBJECTIVE: To describe characteristics, treatment, and outcomes of critically ill patients in Canada with 2009 influenza A(H1N1) infection. DESIGN, SETTING, AND PATIENTS: A prospective observational study of 168 critically ill patients with 2009 influenza A(H1N1) infection in 38 adult and pediatric intensive care units (ICUs) in Canada between April 16 and August 12, 2009. MAIN OUTCOME MEASURES: The primary outcome measures were 28-day and 90-day mortality. Secondary outcomes included frequency and duration of mechanical ventilation and duration of ICU stay. RESULTS: Critical illness occurred in 215 patients with confirmed (n = 162), probable (n = 6), or suspected (n = 47) community-acquired 2009 influenza A(H1N1) infection. Among the 168 patients with confirmed or probable 2009 influenza A(H1N1), the mean (SD) age was 32.3 (21.4) years; 113 were female (67.3%) and 50 were children (29.8%). Overall mortality among critically ill patients at 28 days was 14.3% (95% confidence interval, 9.5%-20.7%). There were 43 patients who were aboriginal Canadians (25.6%). The median time from symptom onset to hospital admission was 4 days (interquartile range [IQR], 2-7 days) and from hospitalization to ICU admission was 1 day (IQR, 0-2 days). Shock and nonpulmonary acute organ dysfunction was common (Sequential Organ Failure Assessment mean [SD] score of 6.8 [3.6] on day 1). Neuraminidase inhibitors were administered to 152 patients (90.5%). All patients were severely hypoxemic (mean [SD] ratio of Pao(2) to fraction of inspired oxygen [Fio(2)] of 147 [128] mm Hg) at ICU admission. Mechanical ventilation was received by 136 patients (81.0%). The median duration of ventilation was 12 days (IQR, 6-20 days) and ICU stay was 12 days (IQR, 5-20 days). Lung rescue therapies included neuromuscular blockade (28% of patients), inhaled nitric oxide (13.7%), high-frequency oscillatory ventilation (11.9%), extracorporeal membrane oxygenation (4.2%), and prone positioning ventilation (3.0%). Overall mortality among critically ill patients at 90 days was 17.3% (95% confidence interval, 12.0%-24.0%; n = 29). CONCLUSION: Critical illness due to 2009 influenza A(H1N1) in Canada occurred rapidly after hospital admission, often in young adults, and was associated with severe hypoxemia, multisystem organ failure, a requirement for prolonged mechanical ventilation, and the frequent use of rescue therapies.

Overdiagnosis of asthma in obese and nonobese adults.

BACKGROUND: It is unclear whether asthma is overdiagnosed in developed countries, particularly among obese individuals, who may be more likely than nonobese people to experience dyspnea. METHODS: We conducted a longitudinal study involving nonobese (body mass index 20-25) and obese (body mass index >/= 30) individuals with asthma that had been diagnosed by a physician. Participants were recruited from 8 Canadian cities by means of random-digit dialing. A diagnosis of current asthma was excluded in those who did not have evidence of acute worsening of asthma symptoms, reversible airflow obstruction or bronchial hyperresponsiveness, despite being weaned off asthma medications. We stopped asthma medications in those in whom a diagnosis of asthma was excluded and assessed their clinical outcomes over 6 months. RESULTS: Of 540 individuals with physician-diagnosed asthma who participated in the study, 496 (242 obese and 254 nonobese) could be conclusively assessed for a diagnosis of asthma. Asthma was ultimately excluded in 31.8% (95% confidence interval [CI] 26.3%-37.9%) in the obese group and in 28.7% (95% CI 23.5%-34.6%) in the nonobese group. Overdiagnosis of asthma was no more likely to occur among obese individuals than among nonobese individuals (p = 0.46). Of those in whom asthma was excluded, 65.5% did not need to take asthma medication or seek health care services because of asthma symptoms during a 6-month follow-up period. INTERPRETATION: About one-third of obese and nonobese individuals with physician-diagnosed asthma did not have asthma when objectively assessed. This finding suggests that, in developed countries such as Canada, asthma is overdiagnosed.

Tiotropium in combination with placebo, salmeterol, or fluticasone-salmeterol for treatment of chronic obstructive pulmonary disease: a randomized trial.

BACKGROUND: Treatment of moderate or severe chronic obstructive pulmonary disease (COPD) with combinations of inhaled corticosteroids, long-acting beta-agonists, and long-acting anticholinergic bronchodilators is common but unstudied. OBJECTIVE: To determine whether combining tiotropium with salmeterol or fluticasone-salmeterol improves clinical outcomes in adults with moderate to severe COPD compared with tiotropium alone. DESIGN: Randomized, double-blind, placebo-controlled trial conducted from October 2003 to January 2006. SETTING: 27 academic and community medical centers in Canada. PATIENTS: 449 patients with moderate or severe COPD. INTERVENTION: 1 year of treatment with tiotropium plus placebo, tiotropium plus salmeterol, or tiotropium plus fluticasone-salmeterol. MEASUREMENTS: The primary end point was the proportion of patients who experienced an exacerbation of COPD that required treatment with systemic steroids or antibiotics. RESULTS: The proportion of patients in the tiotropium plus placebo group who experienced an exacerbation (62.8%) did not differ from that in the tiotropium plus salmeterol group (64.8%; difference, -2.0 percentage points [95% CI, -12.8 to 8.8 percentage points]) or in the tiotropium plus fluticasone-salmeterol group (60.0%; difference, 2.8 percentage points [CI, -8.2 to 13.8 percentage points]). In sensitivity analyses, the point estimates and 95% confidence bounds shifted in the direction favoring tiotropium plus salmeterol and tiotropium plus fluticasone-salmeterol. Tiotropium plus fluticasone-salmeterol improved lung function (P = 0.049) and disease-specific quality of life (P = 0.01) and reduced the number of hospitalizations for COPD exacerbation (incidence rate ratio, 0.53 [CI, 0.33 to 0.86]) and all-cause hospitalizations (incidence rate ratio, 0.67 [CI, 0.45 to 0.99]) compared with tiotropium plus placebo. In contrast, tiotropium plus salmeterol did not statistically improve lung function or hospitalization rates compared with tiotropium plus placebo. LIMITATIONS: More than 40% of patients who received tiotropium plus placebo and tiotropium plus salmeterol discontinued therapy prematurely, and many crossed over to treatment with open-label inhaled steroids or long-acting beta-agonists. CONCLUSIONS: Addition of fluticasone-salmeterol to tiotropium therapy did not statistically influence rates of COPD exacerbation but did improve lung function, quality of life, and hospitalization rates in patients with moderate to severe COPD. International Standard Randomised Controlled Trial registration number: ISRCTN29870041.

Is obesity associated with an increased risk for airway hyperresponsiveness and development of asthma?

: We investigated the association between airway hyperresponsiveness (AHR) and obesity in adults referred for confirmation of asthma diagnosis. Data were analyzed for obesity class I (body mass index [BMI] 30-34.9 kg/m2), class II (BMI >/= 35-39.9 kg/m2), and class III (BMI >/= 40 kg/m2). Of 861 subjects, 401 demonstrated AHR; the mean dose of methacholine was 4.16 +/- 2.55 mg/mL. A significant association between obesity and AHR was evident for all subjects: the odds ratio was 1.37 (95% CI 1.02-1.82; p = .0317). One unit of increased BMI (1 kg/m2) was associated with a 3.1% increase in AHR risk (95% CI 1.01-1.05, p < .005). The odds ratio increased from 1.86 (95% CI 1.27-1.76; p = .0012) for class I to 2.61 (95% CI 1.48-4.60; p = .0006) for class III. Obesity was found to be associated with AHR and appears to be a risk factor for asthma.

Has mediastinoscopy still a role in suspected stage I sarcoidosis?

INTRODUCTION: Whether diagnostic mediastinoscopy is needed for confirmation of diagnosis in patients who present with clinical stage I sarcoidosis and no lung lesions on CT scan, is not known. METHODS: A retrospectively review of all mediastinoscopies performed from 1992 to 2003 at Health Sciences center, Winnipeg, Canada yielded 55 patients with hilar and mediastinal lymphadenopathy and normal lung parenchyma on thoracic computerized axial Scan. RESULTS: Out of a total of 1462 procedures, 55 patients with a presumptive diagnosis of Stage I sarcoidosis underwent mediastinoscopy. Median age at presentation was 47.4 +/- 12.8 years (range 24-77). The patients had mild symptoms of cough (30.9%), dyspnea (20.0%), chest pain (14.6%), malaise in (20.0%), erythema nodosum (3.6%) and uveitis (3.6%). Thoracic CT scan revealed bilateral hilar lymphadenopathy in 9 (16%), bilateral hilar lymphadenopathy plus right paratracheal lymphadenopathy in 35 (63%), right paratracheal lymphadenopathy in 7 (12%) and unilateral hilar lymphadenopathy in 4 (7.1%) subjects. Pathology revealed noncaseating granuloma, suggestive of sarcoidosis in 49 (89.1%), reactive lymph nodes in 5 (9.1%) and was nondiagnostic in 1 (1.8%). Only 2 out of these 6 non-sarcoid patients had bilateral hilar lymphadenopathy. Biopsy cultures were negative for fungus and mycobacterium in all patients. CONCLUSION: Clinical presentation of minimal symptoms, mediastinal lymphadenopathy (especially bilateral hilar and right paratracheal lymphadenopathy) with normal parenchyma on CT scan strongly suggests a diagnosis of sarcoidosis. In these cases, confirmation of the diagnosis by mediastinoscopy and lymph node biopsy is unwarranted.

Role of antimicrobial agents in the management of exacerbations of COPD.

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a common occurrence and characterize the natural history of the disease. Over the past decade, new knowledge has substantially enhanced our understanding of the pathogenesis, outcome and natural history of AECOPD. The exacerbations not only greatly reduce the quality of life of these patients, but also result in hospitalization, respiratory failure, and death. The exacerbations are the major cost drivers in consumption of healthcare resources by COPD patients. Although bacterial infections are the most common etiologic agents, the role of viruses in COPD exacerbations is being increasingly recognized. The efficacy of antimicrobial therapy in acute exacerbations has established a causative role for bacterial infections. Recent molecular typing of sputum isolates further supports the role of bacteria in AECOPD. Isolation of a new strain of Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae was associated with a considerable risk of an exacerbation. Lower airway bacterial colonization in stable patients with COPD instigates airway inflammation, which leads to a protracted self-perpetuating vicious circle of progressive lung damage and disease progression. A significant proportion of patients treated for COPD exacerbation demonstrate incomplete recovery, and frequent exacerbations contribute to decline in lung function. The predictors of poor outcome include advanced age, significant impairment of lung function, poor performance status, comorbid conditions and history of previous frequent exacerbations requiring antibacterials or systemic corticosteroids. These high-risk patients, who are likely to harbor organisms resistant to commonly used antimicrobials, should be identified and treated with antimicrobials with a low potential for failure. An aggressive management approach in complicated exacerbations may reduce costs by reducing healthcare utilization and hospitalization.

Hepatic hydrothorax -- how would you manage it?

A 53-year-old woman with a history of chronic alcoholism presented with symptomatic large right-sided pleural effusion with no evidence of ascites. After a diagnosis of hepatic hydrothorax was established, her symptoms improved with therapeutic thoracentesis. She required multiple emergency department visits for recurrent right-sided pleural effusion treated with urgent therapeutic taps. Hepatic hydrothorax is a relatively infrequent but potentially serious complication of liver cirrhosis. The management of hepatic hydrothorax, usually required in symptomatic patients, is controversial and contradictory. The case summary is followed by a question regarding available management options. The pathophysiology of hepatic hydrothorax, the role of various therapeutic options and the current favoured therapy for this not so uncommon disorder are reviewed.

Secondary pulmonary arterial hypertension: treated with endothelin receptor blockade.

Secondary pulmonary arterial hypertension (SPAH) is an adverse outcome of a variety of systemic disorders. These include collagen vascular diseases, chronic thromboembolism, human immunodeficiency virus, portopulmonary hypertension, and other diseases. Progression of SPAH may persist despite stabilization of the causative disease, thereby contributing to the poor quality of life and unfavorable survival in these patients. Treatment of the underlying cause and oxygen supplementation may alleviate symptoms, but no specific therapy to treat SPAH currently exists. Endothelin receptor blockade with bosentan has been shown to be beneficial in the treatment of primary pulmonary hypertension, but efficacy of this therapy in SPAH has not been established. We describe a case series of 6 patients with disparate causes of SPAH, who benefited from endothelin receptor blockade therapy. The causes of SPAH included collagen vascular disease (scleroderma) (1); systemic lupus erythematosus (2); chronic thromboembolic disease (2); and granulomatous vasculitis from sarcoidosis (1). Therapy with bosentan led to improvements in symptoms, New York Heart Association functional class, and walking distance in all patients. Distance walked in 6 minutes increased from a mean of 151.67 +/- 69.30 m at baseline to 314.83 +/- 89.09 m after an average of 14 months of bosentan treatment. Pulmonary arterial pressure decreased in most but not all 6 patients on follow-up echocardiography. This case series suggests a role for endothelin receptor blockade therapy in SPAH and should generate further interest in pharmacologic management of SPAH. A prospective controlled clinical trial of bosentan in SPAH is urgently needed.

Pulmonary interstitial fibrosis as a presenting manifestation in perinuclear antineutrophilic cytoplasmic antibody microscopic polyangiitis.

Microscopic polyangiitis (MPA) is one of the vasculitides that is included in the pulmonary renal syndromes. Pathologically, MPA has been defined as necrotizing vasculitis with few or no immune deposits, primarily affecting small vessels including arterioles, venules, or capillaries. Pulmonary interstitial fibrosis (PIF) as an accompanying manifestation in MPA has not been widely appreciated. In the present study, we report six cases of MPA at our institution with radiographic evidence of PIF that was apparent before any treatment was administered. All had biopsy evidence of renal disease that was consistent with MPA as well as positive serum perinuclear antineutrophilic cytoplasmic antibody titers. Hemoptysis was observed in approximately one half of the patients. As determined by CT of the chest, PIF was detected in all of the patients and was often present years before a diagnosis of MPA was made. We conclude that PIF may occur as a pulmonary manifestation of MPA. Further appreciation of this finding may lead to more data with respect to the incidence of PIF in MPA, and to a better understanding of the mechanisms that are involved in the development of this finding.

Outcome of patients admitted to the intensive care unit for acute exacerbation of idiopathic pulmonary fibrosis.

RATIONALE: The aim of this study was to evaluate the outcome of intensive care unit (ICU) admission in patients with idiopathic pulmonary fibrosis (IPF) who develop acute respiratory failure of unknown etiology. METHODS: A retrospective study at University of Manitoba hospitals reviewed all patients admitted to the ICU from November 1988 to December 2000 with IPF requiring mechanical ventilation for unknown causes of acute respiratory failure. Survival at hospital discharge was assessed as the primary end point and ICU length of stay as a secondary end point. In the absence of open lung biopsy, major and minor clinical criteria (as per American Thoracic Society statements) were used for the diagnosis of IPF. Infections were ruled out by extensive surveillance cultures and/or bronchoscopy with bronchoalveolar lavage. RESULTS: Eighty-eight charts were reviewed and 25 patients met the inclusion criteria. The mean (+/- SD) age was 69+/-11 years (range 42 to 96 years) and 23 patients were male. With the exception of one survivor who was discharged home, 21 patients died while receiving mechanical ventilation, and three patients died in hospital shortly after ICU discharge (one day, 22 days and 67 days). Intubation and mechanical ventilation were administered to 21 patients, with a mean duration of 11+/-6 days (range two to 27 days); the other four patients were treated with noninvasive ventilation. The average duration of symptoms before ICU admission was 22+/-26 days. All patients were treated with systemic corticosteroids, while eight patients received additional chemotherapy. CONCLUSIONS: In the absence of a reversible cause, patients with IPF who develop acute exacerbation of IPF may not benefit from ICU admission and mechanical ventilation. However, it is imperative that a diagnostic workup be performed to rule out an infectious or other reversible cause of respiratory failure before admission to the ICU is denied.