Background Preterm birth and respiratory support with invasive mechanical ventilation frequently leads to bronchopulmonary dysplasia (BPD). A hallmark feature of BPD is alveolar simplification. For our preterm lamb model of BPD, invasive mechanical ventilation is associated with postnatal feeding intolerance (reduced nutrition) and sedation. In contrast, preterm lambs managed by non-invasive support (NIS) have normal alveolar formation, appropriate postnatal nutrition, and require little sedation. We used the latter, positive-outcome group to discriminate the contribution of reduced nutrition versus sedation on alveolar simplification. We hypothesized that, restricted nutrition, but not sedation, contributes to impaired indices of alveolar formation in preterm lambs managed by NIS. Methods Preterm lambs managed by NIS for 21d were randomized into three groups: NIS control, NIS plus restricted nutrition, and NIS plus excess sedation. We quantified morphological and biochemical indices of alveolar formation, as well as mesenchymal cell apoptosis and proliferation. Results Restricted nutrition impaired morphological and biochemical indices of alveolar formation, and reduced mesenchymal cell apoptosis and proliferation. Excess sedation did not alter these indices, although mesenchymal cell apoptosis was less. Conclusions Our results demonstrate that restricted nutrition, but not excess sedation, contributes to impaired alveolar formation during the evolution of BPD in chronically ventilated preterm lambs.

Background Prematurity is often complicated by respiratory support, including invasive mechanical ventilation (IMV) and non-invasive support (NIS). Compared to IMV, NIS reduces injury to the lung and brain. Prematurity may also disrupt glomerular architecture. Whether NIS differentially affects glomerular architecture is incompletely understood. We hypothesized that IMV would lead to greater disruption of glomerular architecture than NIS. Methods This is a secondary analysis of kidneys from moderately preterm lambs delivered at ∼131d gestation (term ∼150d) that had antenatal steroid exposure and surfactant treatment before resuscitation by IMV. At ∼3h of age, half of the lambs were switched to NIS. Support was for 3d or 21d. Structural indices of glomerular architecture were quantified. Results The number of glomerular generations was unaffected by moderate preterm birth and respiratory support, either IMV or NIS. At 3d and 21d of IMV or NIS, glomerular capillary surface density was not different. Glomerular capillary surface density was significantly lower in the inner and outer cortex compared to unventilated gestation age-matched or postnatal age-matched reference lambs. Conclusion Moderate preterm birth and invasive or non-invasive respiratory support decreases glomerular capillarisation in the lamb kidney. This adverse effect on glomerular development may contribute to increased risk for adult-onset hypertension and renal dysfunction.

Introduction: Asian Americans make up a sizable minority in the US, with Chinese currently making up the largest subgroup. However, despite this fact, the majority of Chinese women in North America underutilize Pap testing and carry a disproportionately higher rate of invasive cervical cancer. It has been suggested that certain cultural beliefs and practices can interfere with Western health care utilization among newly arrived immigrant communities. Methods: Fifteen hundred thirty-two women ages 20 to 69 from Seattle, Washington and Vancouver, BC were interviewed in person in 1999, and data from 993 participants were analyzed. Results: Women who observed postpartum rituals or who believed that certain aspects of their rituals help prevent them from obtaining cervical cancer did not show an underutilization of Pap testing. However, other factors, such as having a car in the household, speaking English, or being married, were highly predictive of Chinese women's Pap test utilizations. Discussion: Based on these findings, postpartum practices do not seem to negatively influence Pap test utilization among Chinese women in North America. Instead, clinicians serving Chinese in North America should focus more on economic, language, and acculturation as potential barriers for their patients' health care utilization.

No abstract

BackgroundIn 1877, Paul Ehrlich devised a system that identified hematopoietic stem cells (HSCs). A century later, a system for the in vitro culture of HSCs was devised. Over the past four decades, great progress in HSC biology has resulted from murine models. Unfortunately, human HSC differentiation models have been difficult to produce. Specifically, the in vitro culture of polymorphonuclear leukocytes (PMNs) from human HSCs has been difficult, and to date, specific methods for this culture have not been defined. Here we describe a precise model for reliable differentiation of PMNs from human umbilical cord blood stem cells.MethodsHSCs were isolated from human umbilical cord blood from full-term neonates. The cord blood underwent magnetic bead-mediated positive selection for CD34 HSCs. HSCs were cultured in X-Vivo 20 with 10% PHS for 16 days. The media was augmented with SCF 100 ng/mL and IL-3 10 ng/mL for the initial 8 days, and G-CSF 20 ng/mL for the entire culture. The cell population was purified by magnetically selecting CD16 cells. Cell morphology was verified with Wright-Giemsa staining and immunocytochemistry (ICC). Cell surface markers were verified with flow cytometry. Functional assay of respiratory burst was performed using dihydrorhodamine (DHR) and phorbol myristate acetate (PMA) to determine stimulation index. Finally, adhesion characteristics were verified with a P-selectin-mediated cell adhesion assay.ResultsMorphologic evaluation demonstrated cultures with a high percentage of leukocytes with multilobed nuclei, consistent with mature PMNs. ICC probing for CD18 confirmed the presence of this PMN-specific adhesion molecule. Flow cytometric analysis indicated that the cultured cells express CD16 and CD18, indicating the presence of mature neutrophils. Respiratory burst activity following DHR/PMA assay indicated intact free radical production. Adhesion of cells to P-selectin-coated plates demonstrated integrity of P-selectin/PSGL-1 adhesion.ConclusionsThese results demonstrate that mature and functional PMNs can be efficiently cultured from human umbilical cord blood stem cells. Although HSC culture of mature human PMNs has been difficult for a generation of cell biologists, this investigation demonstrates detailed methodology for consistent culturing of PMNs from human HSCs. The utility of this model to delineate ontogenic events in PMN differentiation will afford greater understanding of variable phenotypes encountered in human disease.