Successful biodegradable stent insertion in an infant with severe bronchomalacia and cystic fibrosis.

We report the first case of biodegradable airway stent insertion for a patient with bronchomalacia and cystic fibrosis (CF). This female infant with antenatally diagnosed cystic fibrosis developed respiratory distress by three weeks of age. On lower airway examination she was found to have severe left main stem bronchomalacia causing left upper lobe hyperinflation and subsequent right upper lobe collapse. By eight weeks of age she developed life-threatening respiratory failure requiring high pressure invasive ventilation. A biodegradable bronchial stent was inserted to the left main bronchus at thirteen weeks of age with successful extubation from invasive respiratory support four days later. A second biodegradable stent was inserted nine weeks later, due to persistent bronchomalacia following stent degradation and redevelopment of oxygen requirement. She was discharged home off all respiratory support eight weeks later and has remained well, requiring no further surgical intervention for bronchomalacia to date, now age three years.

The impact of altered herbicide residues in transgenic herbicide-resistant crops on standard setting for herbicide residues.

The global area covered with transgenic (genetically modified) crops has rapidly increased since their introduction in the mid-1990s. Most of these crops have been rendered herbicide resistant, for which it can be envisaged that the modification has an impact on the profile and level of herbicide residues within these crops. In this article, the four main categories of herbicide resistance, including resistance to acetolactate-synthase inhibitors, bromoxynil, glufosinate and glyphosate, are reviewed. The topics considered are the molecular mechanism underlying the herbicide resistance, the nature and levels of the residues formed and their impact on the residue definition and maximum residue limits (MRLs) defined by the Codex Alimentarius Commission and national authorities. No general conclusions can be drawn concerning the nature and level of residues, which has to be done on a case-by-case basis. International residue definitions and MRLs are still lacking for some herbicide-crop combinations, and harmonisation is therefore recommended.

Altered pesticide use on transgenic crops and the associated general impact from an environmental perspective.

The large-scale commercial cultivation of transgenic crops has undergone a steady increase since their introduction 10 years ago. Most of these crops bear introduced traits that are of agronomic importance, such as herbicide or insect resistance. These traits are likely to impact upon the use of pesticides on these crops, as well as the pesticide market as a whole. Organizations like USDA-ERS and NCFAP monitor the changes in crop pest management associated with the adoption of transgenic crops. As part of an IUPAC project on this topic, recent data are reviewed regarding the alterations in pesticide use that have been observed in practice. Most results indicate a decrease in the amounts of active ingredients applied to transgenic crops compared with conventional crops. In addition, a generic environmental indicator -- the environmental impact quotient (EIQ) -- has been applied by these authors and others to estimate the environmental consequences of the altered pesticide use on transgenic crops. The results show that the predicted environmental impact decreases in transgenic crops. With the advent of new types of agronomic trait and crops that have been genetically modified, it is useful to take also their potential environmental impacts into account.

Organochlorine pesticide residues in breastmilk: difficulties in sample collection and in assessing intakes.

Organochlorine pesticides are highly lipophilic and stable resulting both in their persistence in the environment and their tendency to pass up the food chain. Residues of these compounds are detectable in breastmilk and have been monitored since the 1950s. Samples can be collected using non-invasive techniques and the results are frequently used to assess degradation in the environment as well as risks to recipient infants. As a food, breastmilk is unique. It is manufactured entirely for an individual consumer with some of its constituents driven by its recipient. It can form the sole source of nutrition for a considerable period of an infant's life. Standard calculations of exposure to residues rely on consumption of 750-850 ml breastmilk day(-1) containing 3.5% fat for a 5-kg infant. The fat content of breastmilk, however, is highly variable, which means that that using fixed breastmilk volumes and fat can lead to an imprecise calculation of individual risk. The fat concentration of breastmilk changes throughout a single feed, between feeds and as lactation progresses. This variation therefore raises the methodological problem of how to secure a representative sample of breastmilk. Furthermore, maternal factors such as age and parity also affect concentrations because of the persistence of organochlorine pesticide residues in maternal fat stores. It is therefore critical that samples are collected in a systematic manner taking account of these variables, particularly if the results not only are to be used for risk assessment, but also in comparing changes in environmental concentrations. Reviews of the literature have shown that these variables have often been disregarded in drawing up sampling strategies and methodologies are poorly reported in publications. The paper discusses the literature currently available on monitoring organochlorine pesticide residues in breastmilk and presents an overview of some of the factors that need to be taken into account when collecting samples and assessing infant exposure.