OBJECTIVE: Central lines in NICUs have long dwell times. Success in reducing central line-associated bloodstream infections (CLABSIs) requires a multidisciplinary team approach to line maintenance and insertion. The Perinatal Quality Collaborative of North Carolina (PQCNC) CLABSI project supported the development of NICU teams including parents, the implementation of an action plan with unique bundle elements and a rigorous reporting schedule. The goal was to reduce CLABSI rates by 75%. METHODS:Thirteen NICUs participated in an initiative developed over 3 months and deployed over 9 months. Teams participated in monthly webinars and quarterly face-to-face learning sessions. NICUs reported on bundle compliance and National Health Surveillance Network infection rates at baseline, during the intervention, and 3 and 12 months after the intervention. Process and outcome indicators were analyzed using statistical process control methods (SPC). RESULTS:Near-daily maintenance observations were requested for all lines with a 68% response rate. SPC analysis revealed a trend to an increase in bundle compliance. We also report significant adoption of a new maintenance bundle element, central line removal when enteral feedings reached 120 ml/kg per day. The PQCNC CLABSI rate decreased 71%, from 3.94 infections per 1000 line days to 1.16 infections per 1000 line days with sustainment 1 year later (P 5 .01). CONCLUSIONS:A collaborative structure targeting team development, family partnership, unique bundle elements and strict reporting on line care produced the largest reduction in CLABSI rates for any multiinstitutional NICU collaborative.

Transverse sections of immature and mature sugarcane internodes were investigated anatomically with white and fluorescence light microscopy. The pattern of lignification and suberization was tested histo‐chemically. Lignification began in the xylem of vascular bundles and progressed through the sclerenchymatic bundle sheath into the storage parenchyma. Suberization began in parenchyma cells adjacent to vascular bundle sheaths and spread to the storage parenchyma and outer sheath cells. In mature internodes most of the storage parenchyma was lignified and suberized to a significant degree, except in portions of walls of isolated cells. The pattern of increasing lignification and suberization in maturing internodes more or less paralleled an increase of sucrose in stem tissue. In mature internodes having a high sucrose concentration, the vascular tissue was surrounded by thick‐walled, lignified and suberized sclerenchyma cells. The apoplastic tracer dyes triso‐dium 3‐hydroxy‐5,8,10‐pyrenetrisulfonate (PTS) and amido black 10 B, fed into cut ends of the stalk, wereconfined to the vascular bundles in all internodes above the one that was cut — with no dye apparently in storage parenchyma tissue. Thus both structural and experimental evidence is consistent with vascular tissue being increasingly isolated from the storage parenchyma as maturation of the tissue proceeds. We conclude that in mature internodes the pathway for sugars from the phloem to the storage parenchyma is symplastic. The data suggest that an increasingly greater role for a symplastic pathway of sugar transfer occurs as the tissue undergoes lignification/suberization.

Both the mesophyll and bundle-sheath cells associated with the minor veins in the leaf of Amaranthus retroflexus L. contain abundant tubular endoplasmic reticulum, which is continuous between the two cell types via numerous plasmodesmata in their common walls. In bundle-sheath cells, the tubular endoplasmic reticulum forms an extensive network that permeates the cytoplasm, and is closely associated, if not continuous, with the delimiting membranes of the chloroplasts, mitochondria, and microbodies. Both the number and frequency of plasmodesmata between various cell types decrease markedly from the bundle-sheath - vascular-parenchyma cell interface to the sicve-tube member - companion-cell interface. For plants taken directly from lighted growth chambers, a stronger mannitol solution (1.4 M) was required to plasmolyze the companion cells and sieve-tube members than that (0.6 M) necessary to plasmolyze the mesophyll, bundle-sheath, and vascular-parenchyma cells. Placing plants in the dark for 48 h reduced the solute concentration in all cell types. Judging from the frequency of plasmodesmata between the various cell types of the vascular bundles, and from the solute concentrations of the various cell types, it appears that assimilates are actively accumulated by the sieve-tube - companion-cell complex from the apoplast.

No abstract