We conclude that low tracheal aspirate levels of TIMPs, with a high MMP-9/TIMP-1 ratio early in life, are associated with subsequent development of CLD.

No abstract

The risk for rehospitalization for infants requiring tracheostomy and ventilator support was affected by prolonged oxygen use, prolonged ventilator dependence, inhaled steroid use and equipment malfunction, and was equally distributed throughout the first 2 years of life.

Although the skeletal muscles of different vertebrate species have been assumed to be generally similar, recent X-ray diffraction and mechanical studies have demonstrated differences in the responses of these muscles to changes in physiological conditions. X-ray diffraction studies have indicated that lowering the temperature and lowering ionic strength may affect the crossbridge arrangement of rabbit thick filaments. Similar X-ray diffraction studies on the structural effects of lowering ionic strength in frog and fish muscles are less clear in interpretation, while lowering the temperature appears to have little effect in these muscles. In the present study we have compared the effects of lowering the temperature or ionic strength on the crossbridge order of isolated rabbit and fish thick filaments as observed in the electron microscope. In agreement with the X-ray results, rabbit filaments show a distinct loss of crossbridge order when stained at 4 degrees C compared to 25 degrees C, whereas fish thick filaments appear similar at both temperatures. Rabbit thick filaments, when diluted to one-fourth of the normal ionic strength (while maintaining constant EGTA and ATP concentration), showed a strong tendency to bind to actin filaments, while similarly-treated fish filaments showed little tendency to aggregate or become disordered. These results appear to support the X-ray diffraction results of other investigators, and the idea that effects of ionic strength or temperature on muscle may vary with species.

Clinical criteria independently associated with neurogenic claudication due to LSS were identified. The use of these symptom and physical variables as a classification score for clinical research could improve homogeneity among enrolled patients.

Microvascular development is critical for normal lung maturation. The aims of this study were (1) to quantitatively and qualitatively assess lung microvascular growth in the human fetus, from 22 to 40 weeks’ gestation, and (2) to compare development in these infants to those with mild, moderate and severe chronic lung disease (CLD). Using 1- and 4-µm thick sections and electron microscopy, lungs were morphometrically assessed for surface density of distal air spaces; volume density of parenchymal vessels having an air-blood barrier (ABB); percent of distal air space wall having an ABB, and capillary loading, defined as ABB/mm² of epithelial surface area. The percent of vessels with ABB increased in controls during development in parallel with increasing lung parenchyma. Infants with severe CLD had fewer ABBs and less capillary loading than controls up to 34 weeks’ post-conceptional age (PCA), but by 36–40 weeks, showed catch-up growth. Microvasculature vessel diameter, septal thickness, and air sac diameter at 36–40 weeks’ PCA were increased with severe CLD, and vessels were more distant from the air surface. We conclude that infants with severe CLD have both stunted secondary septation and microvascular development, but over time, the primary septal wall adapts by thinning and increasing the number of ABBs, thereby taking on the function of secondary septa.

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Adding an exercise programme after functional multidisciplinary rehabilitation compared with usual care does not offer significant long-term benefits in quality of life and direct and indirect costs.