The quandary of sources and sinks of CO2 efflux in tree stems-new insights and future directions.

Stem respiration (RS) substantially contributes to the return of photo assimilated carbon to the atmosphere and, thus, to the tree and ecosystem carbon balance. Stem CO2 efflux (ECO2) is often used as a proxy for RS. However, this metric has often been challenged because of the uncertain origin of CO2 emitted from the stem due to post-respiratory processes.

Carbon dynamics during long-term starving poplar trees-the importance of older carbohydrates and a shift to lipids during survival.

Carbon (C) assimilation can be severely impaired during periods of environmental stress like drought or defoliation, making trees heavily dependent on the use of C reserve pools for survival; yet, dynamics of reserve use during periods of reduced C supply are still poorly understood. We used stem girdling in mature poplar trees (Populus tremula L. hybrids), a lipid-storing species, to permanently interrupt phloem C transport and induced C shortage in the isolated stem section below the girdle and monitored metabolic activity during three campaigns in the growing seasons of 2018, 2019, and 2021.

Differences between tree stem CO efflux and O influx rates cannot be explained by internal CO transport or storage in large beech trees.

Tree stem respiration (R ) is a substantial component of the forest carbon balance. The mass balance approach uses stem CO efflux and internal xylem fluxes to sum up R , while the oxygen-based method assumes O influx as a proxy of R . So far, both approaches have yielded inconsistent results regarding the fate of respired CO in tree stems, a major challenge for quantifying forest carbon dynamics.

Low-cost chamber design for simultaneous CO2 and O2 flux measurements between tree stems and the atmosphere.

Tree stem CO2 efflux is an important component of ecosystem carbon fluxes and has been the focus of many studies. While CO2 efflux can easily be measured, a growing number of studies have shown that it is not identical with actual in situ respiration. Complementing measurements of CO2 flux with simultaneous measurements of O2 flux provides an additional proxy for respiration, and the combination of both fluxes can potentially help getting closer to actual measures of respiratory fluxes.

Measuring the ratio of CO2 efflux to O2 influx in tree stem respiration.

In recent studies, the ratio of tree stem CO efflux to O influx has been defined as the apparent respiratory quotient (ARQ). The metabolism of carbohydrates, the putative respiratory substrate in trees, is expected to yield an ARQ of 1.0.

An official American Thoracic Society clinical practice guideline: classification, evaluation, and management of childhood interstitial lung disease in infancy.

Background: There is growing recognition and understanding of the entities that cause interstitial lung disease (ILD) in infants. These entities are distinct from those that cause ILD in older children and adults.

Methods: A multidisciplinary panel was convened to develop evidence-based guidelines on the classification, diagnosis, and management of ILD in children, focusing on neonates and infants under 2 years of age.

The 2006 ACR Forum: cardiovascular imaging: learning from the past, strategies for the future.

This paper summarizes the 2006 ACR Forum, which explored the history of the relationship between radiology and cardiovascular imaging and sought to explore strategies by which radiology could cope with similar challenges in the future. Key topics include: competition between radiology and other medical specialties, the importance of cardiac imaging, the relative merits of cardiologists and radiologists as cardiovascular imagers, and specific recommendations for radiology leaders in the areas of education, research, clinical practice, and policy.

Diagnosis of interstitial lung disease in children.

Chronic interstitial lung disease (ILD) in infants and children is a challenging diagnostic clinical problem. There are many unresolved and controversial issues in the diagnosis of this heterogeneous group of uncommon disorders in children. Diagnosis requires a high index of suspicion as the initial clinical manifestations are subtle, highly variable and non-specific.

A comparison of microbiologic flora of the sinuses and airway among cystic fibrosis patients with maxillary antrostomies.

The placement of maxillary antrostomies among cystic fibrosis (CF) patients has been used as a treatment to allow localized antibiotic lavage of infected sinus passages. This procedure is increasingly recommended by lung transplantation centers as a prerequisite prior to accepting a CF patient as a candidate for transplantation. Our study attempts to define the degree of identity between sinus, endotracheal and sputum cultures from 35 patients.

Comparison of a beta-lactam alone versus beta-lactam and an aminoglycoside for pulmonary exacerbation in cystic fibrosis.

Unlabelled: We determined whether a beta-lactam and an aminoglycoside have efficacy greater than a beta-lactam alone in the management of a pulmonary exacerbation in patients with cystic fibrosis.

Study Design: Azlocillin and placebo or azlocillin and tobramycin were administered to 76 patients with a pulmonary exacerbation caused by Pseudomonas aeruginosa in a randomized double-blind, third-party monitored protocol. Improvement was assessed by standardized clinical evaluation, pulmonary function testing, sputum bacterial density, sputum DNA content, and time to the next pulmonary exacerbation requiring hospitalization.

Pediatric tuberculosis: problems in diagnosis and issues in management.

The diagnosis of infection and disease due to Mycobacterium tuberculosis in infants and children presents many clinical challenges. The distinction of infection from disease (tuberculosis) in children is often unclear. There is difficulty in obtaining positive microbiological confirmation of infection in sputum, gastric, tracheal, or bronchial aspirates and in other body fluids in infants and children.

Genetic and immunologic aspects of cystic fibrosis.

Learning Objectives: Reading this article will enable the readers to reinforce their knowledge of the pathophysiology of cystic fibrosis (CF), the pathogenesis of the lung disease, the criteria for diagnosis, and CF genotype/phenotype relationships. The focus of this review is on the genetic and immunologic aspects of CF.

Data Source: Relevant articles, current texts, data presented at the annual North American Cystic Fibrosis Conferences and distributed to the Directors of CF Centers by the CF Foundation were reviewed.

Identification of common cystic fibrosis mutations in African-Americans with cystic fibrosis increases the detection rate to 75%.

Cystic fibrosis (CF)--an autosomal recessive disorder caused by mutations in CF transmembrane conductance regulator (CFTR) and characterized by abnormal chloride conduction across epithelial membranes, leading to chronic lung and exocrine pancreatic disease--is less common in African-Americans than in Caucasians. No large-scale studies of mutation identification and screening in African-American CF patients have been reported, to date. In this study, the entire coding and flanking intronic sequence of the CFTR gene was analyzed by denaturing gradient-gel electrophoresis and sequencing in an index group of 82 African-American CF chromosomes to identify mutations.

Flexible fiberoptic rhinoscopy in the diagnosis of nasal polyps in cystic fibrosis.

The incidence of nasal polyps in patients with CF in various studies varies from 6.7% to 48%. Fiberoptic rhinoscopy, a safe and minimally invasive diagnostic procedure, has the major advantage over routine physical examination of the nares because of the ability to examine the nose beyond the nasal vestibule.

Pregnancy in patients with cystic fibrosis.

With increasing life span of patients with CF, more women with CF are becoming pregnant and others are seeking information about the risks involved during pregnancy and delivery. A striking limitation of the available information is the lack of large prospective studies of pregnant patients with CF matched for age and disease severity compared with their non-pregnant cohorts. A study investigating the effect of pregnancy on morbidity and mortality is being completed by the Cystic Fibrosis Foundation.

Successful prenatal management of hydrops, caused by congenital cystic adenomatoid malformation, using serial aspirations.

Congenital cystic adenomatoid malformation (CCAM) is a lung lesion that is now commonly diagnosed in utero with fetal ultrasonography. The described treatment of this lesion includes observation with treatment delivery, a single aspiration, thoraco-amniotic shunts, and fetal resection. This patient had an in utero diagnosis of a Stocker type I CCAM associated with hydrops.