A novel whole "Joint-in-Motion" device reveals a permissive effect of high glucose levels and mechanical stress on joint destruction.

OBJECTIVE: Osteoarthritis (OA) has recently been suggested to be associated with diabetes. However, this association often disappears when accounting for body mass index (BMI), suggesting that mechanical stress may be a confounding factor. We investigated the combined influence of glucose level and loading stress on OA progression using a novel whole joint-in-motion (JM) culture system. DESIGN: Whole mouse knee joints were placed in an enclosed chamber with culture media and actuated to recapitulate leg movement, with a dynamic stress regimen of 0.5 Hz, 8 h/day for 7 days. These joints were treated with varying levels of glucose and controlled for osmolarity and diffusion. Joint movement and joint space were examined by X-ray fluoroscopy and microCT. Cartilage matrix levels were quantified by blinded Mankin scoring and immunohistochemistry. RESULTS: Culturing in the JM device facilitated proper leg extension and flexion movements, and adequate mass transport for analyzing the effect of glucose on cartilage. Treatment with higher levels of glucose either via media supplementation or intra-articular injection caused a significant decrease in levels of glycosaminoglycan (GAG) and an increase in aggrecan neoepitope in articular cartilage, but only under dynamic stress. Additionally, collagen II level was slightly reduced by high glucose levels. CONCLUSIONS: High levels of glucose and dynamic stress have permissive effects on articular cartilage GAG loss and aggrecan degradation, implicating that mechanical stress confounds the association of diabetes with OA. The JM device supports novel investigation of mechanical stress on the integrity of an intact living mouse joint to provide insights into OA pathogenesis.

On the Emergence Mechanism of Carrot Sprites.

We investigate the launch of negative upward streamers from sprite glows. This phenomenon is readily observed in high-speed observations of sprites and underlies the classification of sprites into carrot or column types. First, we describe how an attachment instability leads to a sharply defined region in the upper part of the streamer channel. This region has an enhanced electric field, low conductivity and strongly emits in the first positive system of molecular nitrogen. We identify it as the sprite glow. We then show how, in the most common configuration of a carrot sprite, several upward streamers emerge close to the lower boundary of the glow, where negative charge gets trapped and the lateral electric field is high enough. These streamers cut off the current flowing toward the glow and lead to the optical deactivation of the glow above. Finally, we discuss how our results naturally explain angel sprites.

The p66Shc adapter protein regulates the morphogenesis and epithelial maturation of fetal mouse lungs.

Many signaling pathways are mediated by Shc adapter proteins that, in turn, are expressed as three isoforms with distinct functions. The p66(Shc) isoform antagonizes proliferation, regulates oxidative stress, and mediates apoptosis. It is highly expressed in the canalicular but not the later stages of mouse lung development, and its expression persists in bronchopulmonary dysplasia, a chronic disease associated with premature birth. These observations suggest that p66(Shc) has a developmental function. However, constitutive p66(Shc) deletion yields no morphological phenotype, and the structure of the Shc gene precludes its inducible deletion. To elucidate its function in lung development, we transfected p66(Shc) or nonsilencing small-interfering RNA (siRNA) into the epithelia of embryonic day 11 mouse lungs that were then cultured for 3 days and analyzed morphometrically. To assess cellular proliferation and epithelial differentiation, lung explants were immunostained and immunoblotted for p66(Shc), proliferating cell nuclear antigen (PCNA), the proximal airway differentiation antigens Clara cell 10-kDa protein (CC10) and thyroid transcription factor (TTF)-1, and the alveolar surfactant proteins (SP)-A, -B, and -C. Explants transfected with nonsilencing siRNA demonstrated specific epithelial uptake and normal morphological development relative to uninjected controls. In contrast, transfection with p66(Shc) siRNA significantly increased lumenal cross-sectional areas, decreased branching, and increased epithelial proliferation (P < 0.05 for all). Relative to controls, the expression of SP-B, SP-C, CC10, and TTF-1 was decreased by p66(Shc) knockdown. SP-A was not expressed in either control or treated lungs. These data suggest that p66(Shc) attenuates epithelial proliferation while promoting both distal and proximal epithelial maturation.

Androgen receptors influence the production of pulmonary surfactant in the testicular feminization mouse fetus.

A sexual dimorphism in fetal pulmonary maturation has been described in which the female fetal lung produces surfactant earlier in gestation than the male fetal lung. This is felt to be related to the increased incidence in male newborns of the Respiratory Distress Syndrome. Dihydrotestosterone will delay surfactant production in the female fetus, and a relationship between fetal sexual differentiation and fetal lung maturation has been proposed. We hypothesized that the dimorphism in fetal surfactant production is dependent on androgen receptor function. We measured phosphatidylcholine (PC), saturated phosphatidylcholine (SPC), and sphingomyelin (S) in the amniotic fluid of fetal mice of the mouse model of testicular feminization (Tfm mouse). In this model, male carriers of the X-linked Tfm gene have no functional androgen receptors. The mean amniotic fluid phosphatidylcholine to sphingomyelin ratio (PC/S ratio) was 28% higher in females than in normal males, and the amniotic fluid PC/S ratio of the Tfm male fetuses was the same as the females. The ratio of amniotic fluid saturated phosphatidylcholine to sphingomyelin (SPC/S ratio) was lowest in males, intermediate in females, and highest in Tfm males. A significant relationship between the fetal groups and the amniotic fluid SPC/S ratio was identified by analysis of variance. There were no differences in the whole lung phospholipid content between the three groups. To substantiate the effect of androgen receptors, dihydrotestosterone was injected into pregnant carriers of the Tfm mutation, 2.5 mg/d from day 10 of gestation through the day of sacrifice. The amniotic fluid PC/S ratio was decreased in the female fetuses (consisting of both homozygous normal and heterozygous carriers of the Tfm gene), but not in the Tfm male fetuses. The overall result was no significant difference between the male and female amniotic fluid PC/S ratio while the Tfm amniotic fluid PC/S ratio remained at the level of the untreated females. We conclude that androgens affect fetal lung development via a mechanism dependent on the presence of androgen receptors.

Androgen regulation of epidermal growth factor receptor binding activity during fetal rabbit lung development.

Fetal lung development progresses in a sex-specific manner with male fetuses exhibiting delayed maturation. Androgens, both exogenous and endogenous, inhibit while epidermal growth factor (EGF) enhances fetal lung development. We hypothesized that one mechanism responsible for the delay in male fetal lung development is an androgen-induced delay in EGF receptor binding activity. We measured EGF binding in sex-specific fetal rabbit lung plasma membranes isolated from control fetuses (days 21, 23, 25, 27, 29, and 30 of gestation) and from androgen-treated fetuses (days 21, 23, and 27 of gestation) that had been continuously exposed in vivo to exogenous 5 alpha-dihydrotestosterone from day 12 through 27 of gestation. Specific binding of EGF was significantly lower in male than in female fetal lung tissue isolated from controls at day 21 of gestation. Scatchard analysis revealed that this decrease in EGF binding was associated with decreased EGF receptor density without any significant change in affinity. Prenatal exogenous androgen treatment led to decreased EGF binding in fetal rabbit lung tissue from both sexes secondary to a decrease in EGF receptor density. These findings suggest that one mechanism responsible for the delay in male fetal lung maturation is an androgen-induced delay in EGF receptor binding activity during fetal lung development.

Dihydrotestosterone inhibits fetal rabbit pulmonary surfactant production.

Males have a higher morbidity and mortality for neonatal respiratory distress syndrome (RDS) than females, and respond less well to hormone therapy designed to prevent RDS by stimulating fetal pulmonary surfactant production. We have shown that male fetuses exhibit delayed production of pulmonary surfactant. We tested the hypothesis that the sex difference in fetal pulmonary surfactant production is under hormonal control. Pulmonary surfactant was measured as the saturated phosphatidylcholine/sphingomyelin ratio (SPC/S) in the lung lavage of fetal rabbits at 26 d gestation. There was an association between the sex of neighboring fetuses and the SPC/S ratio of the female fetuses, such that with one or two male neighbors, respectively, females had decreasing SPC/S ratios (P < 0.05). We injected dihydrotestosterone (DHT) into pregnant does from day 12 through day 26 of gestation in doses of 0.1, 1.0, 10, and 25 mg/d, and measured the SPC/S ratio in fetal lung lavage on day 26. In groups with the normal sex difference in fetal serum androgen levels (controls, 0.1 mg DHT/d) the normal sex difference in the SPC/S ratio was also present (females > males, P = 0.03). In the 1-mg/d group there was no sex difference in androgen levels and the sex difference in the SPC/S ratio was also eliminated as the female values were lowered to the male level. Higher doses of DHT (10, 25 mg/d) further reduced the SPC/S ratios. We injected the anti-androgen Flutamide (25 mg/d) from day 12 through day 26 of gestation. This treatment eliminated the normal sex difference in the lung lavage SPC/S ratio by increasing the male ratios to that of the females. We conclude that androgens inhibit fetal pulmonary surfactant production. An understanding of the mechanism of the sex difference in surfactant production may allow development of therapy that is as effective in males as in females for preventing RDS.

The development of surfactant synthesis in fetal rabbit lung organ culture exhibits a sex dimorphism.

Sex differences in amniotic fluid and lung lavage surfactant have been found. Although these studies suggest that augmented fetal surfactant synthesis occurs earlier in the female fetus, there is little direct evidence for a sex difference in fetal surfactant synthesis. We studied the synthesis of surfactant by evaluating the appearance of labelled phospholipids in lamellar bodies recovered from sex-specific organ culture of fetal rabbit lungs. Furthermore, we studied the ability of dexamethasone to stimulate surfactant synthesis in male and female fetal lungs. Organ culture was begun on day 21 of gestation. After 5 days the incorporation of [1,3-14C]glycerol into phosphatidylcholine (PC), disaturated phosphatidylcholine, phosphatidylinositol (PI), and phosphatidylglycerol was studied. Female lungs in organ culture synthesized more disaturated PC per milligram protein than male lungs. In the presence of dexamethasone (10(-8) M) and dihydrotestosterone (10(-8) M) an increased synthesis was noted in the female cultures of PC (270%), disaturated PC (234%), PI (281%), and phosphatidylglycerol (754%). No significant increase in the synthesis of PC or disaturated PC was observed in the male cultures. However in the male cultures smaller increases in the synthesis of PI (193%) and of phosphatidylglycerol (360%) were observed. Overall, dexamethasone stimulated synthesis in females but not in males such that significant differences in the synthesis of all phospholipids were found in the presence of 10(-8) M dexamethasone. These studies show that the synthesis of surfactant in the fetal lung is sexually dimorphic, as is the ability of dexamethasone to regulate synthesis. An understanding of the mechanism which causes these differences may provide important insight into the control of the developmental clock which regulates the orderly progression of development.

Epidermal growth factor influences the developmental clock regulating maturation of the fetal lung fibroblast.

Growth factors may play a significant role in regulating the orderly progression of organ growth and differentiation during fetal development. We hypothesized that epidermal growth factor (EGF) would help regulate the development of surfactant synthesis in the fetal lung by influencing fibroblast-epithelial cell interactions. The effect of EGF (10 ng per ml) on the ability of the fetal lung fibroblast to produce fibroblast pneumonocyte factor (FPF) was studied in sex-specific fibroblasts cultured from day 16, day 17 or day 18 fetal mouse lungs. FPF which is normally not produced by day 16 fibroblasts, is found only in female fibroblasts on day 17, and then in both males and females on day 18. EGF advanced this pattern such that female fibroblasts produced activity on day 16 and fibroblasts from both sexes produced FPF activity on day 17 and day 18. Fibroblasts from an androgen receptor-deficient mouse model confirmed that the effect of EGF was sex-specific and related to the state of development of the fetal lung. We conclude that EGF advances the fetal lung fibroblast through specific stages of development. It appears, therefore, to help control the timing of the clock regulating fetal lung maturation.

Sex-specific differences in rabbit fetal lung maturation in response to epidermal growth factor.

Males and females exhibit different stages of lung development at the same gestation with males lagging behind. We hypothesized that one of the mechanisms responsible for the sex-specific difference in fetal lung maturation is a delay in the onset of epidermal growth factor (EGF) activity in the male fetal lung. EGF influences growth and differentiation during development. We studied the effects of EGF on the incorporation of glycerol into lamellar body disaturated phosphatidylcholine (DSPC) in sex-specific fetal rabbit lung explants prepared at 21 and 24 days gestation (term 31 days). The explants were maintained in Waymouth's media + 10% stripped fetal calf serum with or without EGF (10 ng/ml). The incorporation of [1,3-14C]glycerol into lamellar body DSPC was assessed after 3, 5, or 7 days of culture. Female lung explants prepared at 21 days of gestation had increased incorporation of glycerol into DSPC over time in response to EGF treatment. Male lung explants prepared at 21 days did not respond to EGF treatment. In explants prepared at 24 days gestation, baseline glycerol incorporation into DSPC was higher in female as compared to male fetal lung explants. EGF-responsiveness was also sex-specific in these more mature explants, with the male explants now responding to EGF with a consistent increase in the incorporation of glycerol into lamellar body DSPC. We conclude that one of the mechanisms responsible for the lag in male fetal lung development is a delay in the onset of EGF activity.

Development of fibroblast-type-II cell communications in fetal rabbit lung organ culture.

The development of the fetal lung is regulated by fibroblast-type-II cell communications which involve fibroblast pneumonocyte factor (FPF). FPF production is positively regulated by glucocorticoids and negatively regulated by dihydrotestosterone (DHT) and transforming growth-factor beta (TGF-beta). We studied whether DHT or TGF-beta affected other steps in the process of lung maturation, by studying how the developing lung in organ culture would respond to exogenously supplied FPF after DHT or TGF-beta exposure. Fetal rabbit (day 19 of gestation) lung organ cultures were prepared and cultured in the presence of cortisol, DHT or TGF-beta. After seven days, the media were replaced with serum-free medium containing either cortisol or FPF conditioned medium. The incorporation of [14C]glycerol into surfactant lamellar body DSPC was studied over 24 h as the index of surfactant synthesis. Results were compared to simultaneous control cultures. Treatment had no significant effect on tissue protein concentration or on the efficiency of lamellar body recovery. Cortisol stimulated baseline incorporation of glycerol into DSPC. This was inhibited by DHT, such that DHT plus cortisol treatment was no different from untreated controls. FPF stimulated the incorporation of glycerol into DSPC, and did so even after culture treatment with DHT. Cultures treated with TGF-beta exhibited glycerol incorporation similar to untreated controls. After TGF-beta exposure, FPF did not stimulate glycerol incorporation into DSPC. We conclude that DHT interferes with progression of lung development by delaying the appearance of FPF production by the fibroblast. TGF-beta, on the other hand, inhibits other elements of lung maturation besides FPF production. We speculate that TGF-beta interferes with type-II cell development such that the cell cannot respond to FPF.

Hoxb-5 control of early airway formation during branching morphogenesis in the developing mouse lung.

Hox proteins control structural morphogenesis, pattern formation and cell fate in the developing embryo. To determine if Hoxb-5 participates in patterning of early airway branching during lung morphogenesis, gestational day 11.5 embryonic lung cultures were treated with retinoic acid (RA) to up-regulate and antisense oligonucleotides to down-regulate Hoxb-5 protein expression. RA (10(-6) M) and Hoxb-5 antisense oligonucleotide (20 microM) treatment each significantly decreased branching morphogenesis (P<0. 001), but the morphology of branching under these conditions was very different. RA-treated lungs had elongated primary branches but decreased further branching with increased Hoxb-5 immunostaining in subepithelial regions underlying these elongated airways. Western blots confirmed that Hoxb-5 protein was increased by 189+/-20% (mean+/-S.E.M., P<0.05) in RA-treated lungs compared to controls. In contrast, lungs treated with Hoxb-5 antisense oligos plus RA had foreshortened primary branches with rudimentary distal clefts resulting in decreased numbers of primary and subsequent branches. Immunohistochemistry confirmed that Hoxb-5 antisense oligos inhibited Hoxb-5 protein expression even in the presence of RA. We conclude that regional and quantitative changes in Hoxb-5 protein expression influence morphogenesis of the first airway divisions from the mainstem bronchi. RA-induced alterations in branching are mediated in part through regulated Hoxb-5 expression.

Uptake of the 35 kDa major surfactant apoprotein (SP-A) by neonatal rabbit lung tissue.

Secreted surfactant is made up of both phospholipid and protein components. Therefore, we investigated the possibility that surfactant apoproteins might be taken up by the alveolar type II cell in a manner similar to the uptake of surfactant phosphatidylcholines. Day 2 neonatal rabbits were infused via the trachea with a solution of carrier surfactant and 125I-labelled surfactant apoprotein (SP-A, Mr approx. 35,000). Most of the 125I-SP-A remained within the alveolus; however, a fraction of the 125I-SP-A was taken up by the lung tissue from the alveolus in a time-dependent manner. The small amount of radiolabeled material detected in blood, liver or kidney tissues of 125I-SP-A-infused animals was not trichloroacetic acid (TCA) precipitable, i.e., probably represented degradation products. In contrast, the proportion of TCA-precipitable 125I-SP-A in lung tissue or lavage samples did not change as function of time after tracheal administration. Two-dimensional gel electrophoresis of the 125I-SP-A present in the lavage samples or associated with lung tissue was used to show that a small proportion of the 125I-SP-A was partially degraded in the lung tissue and alveolus. These data are suggestive that the SP-A is taken up by lung tissue, perhaps in a manner similar to the uptake of surfactant phospholipid by the alveolar type II cell.

Regulation of the epidermal growth factor receptor in fetal rat lung fibroblasts during late gestation.

Lung epithelial cell differentiation is predominantly regulated by mesenchymal-epithelial cell communication. We have previously shown that epidermal growth factor (EGF) positively influences this process, and that EGF receptor (EGF-R) binding in fetal rat lung fibroblasts peaks on d18-19 of gestation, just before the onset of augmented surfactant synthesis. This regulation of EGF-R in late gestation fetal lung fibroblasts may control the timing of mesenchymal-epithelial cell communication leading to surfactant synthesis. Hormones and growth factors exert positive and negative influences on lung development, but whether they regulate the EGF-R is unknown. We hypothesized that positive [EGF, cortisol, retinoic acid (RA)] and negative [transforming growth-factor-beta1 (TGF-beta1), dihydrotestosterone (DHT)] regulators of lung cell development regulate the EGF-R in the fetal lung. We studied EGF-R binding and protein abundance in sex-specific fetal rat lung fibroblasts cultured at d17, d19, and d21. EGF-R binding was significantly elevated after RA (both sexes d17 and d19, females d21) and after DHT (females d19) treatment. EGF and cortisol had minimal or inhibitory effects on EGF-R binding. Western blot analysis showed that the observed changes in EGF-R binding were associated with similar changes in EGF-R protein. We conclude that factors that affect lung maturation continue to regulate EGF-R in a developmental, sex-specific manner during late gestation.

Sex differences in avian embryo pulmonary surfactant production: evidence for sex chromosome involvement.

Sex differences in fetal pulmonary surfactant production have been shown in mammalian species, with the female at an advantage. A relationship between fetal sexual differentiation and the development of pulmonary surfactant production has been proposed. We hypothesized that if sex chromosomal factors play a role in causing the surfactant sex difference, then a reversal in the sex karyotype would be associated with a reversal in the surfactant sex difference and in some sex-specific responses to hormonal regulators of fetal surfactant production. To test this, we measured the surfactant-related phospholipids phosphatidylcholine and saturated phosphatidylcholine (SPC) in lung homogenates of avian embryos in which the male sex karyotype is homozygous (ZZ) and the female heterozygous (ZW). The following experimental groups were monitored: untreated controls on days 15 through 21 of gestation; embryos injected with 250 micrograms 17 beta-estradiol or of the antiestrogen CI 628; embryos injected with 250 micrograms testosterone or of the antiandrogen Flutamide; and embryos injected with 0.75 micrograms dexamethasone or 100 micrograms 11-deoxycortisol. Untreated controls exhibited significantly higher PC/milligram lung weight and SPC/milligram lung weight ratios in male embryos at gestation days 15 through 19. Hormone treatments also produced sex-specific effects. Dexamethasone significantly accelerated the male lung SPC concentration (35% over control) without affecting that of females. Glucocorticoid inhibition with 11-deoxycortisol significantly reduced the lung SPC concentration of both males and females, each by 19%. Testosterone significantly increased the female lung SPC concentration by 23%, and Flutamide significantly lowered this in the females by 24%. Estrogen reversed the sex difference by producing a relatively small (16%) decrease in the male lung SPC content while significantly increasing that of the females by 32%. CI 628 produced a modest and proportionate reduction of the lung SPC content in both sexes. These data provide evidence for a male advantage in fetal pulmonary surfactant production in the avian system, the reverse to that observed in humans, rabbits, rats, and mice. The known sex-specific responses of the developing surfactant system to glucocorticoids and to androgens are also reversed in the chick embryo as compared to the mammal. This gives additional support to the proposed link between the process of fetal sexual differentiation and the dimorphism in fetal pulmonary surfactant production and suggests that the sex chromosomes play an important regulatory role in the dimorphism of fetal surfactant production.

Androgen regulation of signaling pathways in late fetal mouse lung development.

During lung development there is tension between positive and negative regulators of fibroblast-epithelial communication controlling type II cell differentiation. A clinical consequence of imbalance of this tension is the increased risk for respiratory distress syndrome in male infants. We hypothesized that chronic intrauterine androgen exposure alters fetal lung fibroblast maturation by down-regulating epidermal growth factor receptor (EGF-R) activity and by up-regulating transforming growth factor-beta receptor (TGFbeta-R) activity, leading to an inhibition of surfactant protein B (SP-B) and -C (SP-C) gene expression in type II cells. We treated pregnant mice with dihydrotestosterone (DHT; 2 mg/day) or vehicle for 7 days, starting on gestational day 11. On day 18, EGF binding, EGF-R phosphorylation, TGFbeta-R binding, and TGFbeta1-induced cell proliferation were studied in sex-specific fibroblast cultures. SP-B and -C messenger RNA levels were measured in whole lungs. Chronic DHT treatment reduced both EGF binding (females to 78+/-8% and males to 65+/-9% of controls) and EGF-induced EGF-R phosphorylation. TGFbeta-R binding was increased (females to 173+/-39% and males to 280+/-64% of controls), and TGFbeta-induced cell proliferation was increased in female cells (231+/-57% of controls). SP-B and -C messenger RNA expression was reduced to 55+/-10% and 75+/-4%, respectively. We conclude that chronic DHT exposure beginning early in lung development alters the balance of growth factor signaling that regulates lung maturation.

Evaluation of the Porta-Warm mattress as a source of heat for neonatal transport.

One risk of transport of newborns to referral centers is hypothermia. Modern transport incubators have limitations in their ability to keep infants euthermic. As tested in the laboratory and during actual transport the Porta-Warm mattress extends the capability of the transport incubator to keep neonates euthermic by (1) reducing the time required to warm the incubator and (2) warming the incubator in cooler environements. The mattress is an effective adjunct to the transport incubator for keeping newborns warm during transport.

Effects of epidermal growth factor (EGF) on the development of EGF-receptor (EGF-R) binding in fetal rabbit lung organ culture.

Epidermal growth factor (EGF) causes gender- and development-specific changes in fetal lung surfactant synthesis. We hypothesized that the effects of EGF on development of surfactant synthesis are related to effects on EGF receptor (EGF-R) expression. We prepared sex-specific fetal rabbit lung organ cultures on gestational days 21 and 24 (term = 31 days) in Waymouth's medium + 10% charcoal-stripped fetal calf serum as control or with added EGF (10 ng/mL). After 3, 5, and 7 days of culture, we measured specific EGF-R binding in fetal lung plasma membrane preparations. Analysis of variance (ANOVA) revealed significant effects of fetal gender (P = 0.0003), time in culture (P = 0.01), and EGF treatment (P = 0. 0003) on EGF specific binding. In control cultures from days 21 and 24 (both male and female), EGF specific binding tended to decrease with time in culture. Specific binding in EGF-treated female 21-day cultures was significantly higher than in controls, both after 5 days (184% of control, P = 0.007) and after 7 days (151% of control, P = 0.01; Bonferroni multiple comparisons) of treatment, whereas males exhibited no response to EGF treatment. As opposed to these effects in 21-day cultures, EGF had little effect on 24-day cultures. We conclude that EGF affects the expression of the EGF-R on EGF specific binding in the fetal lung. The development of surfactant synthesis in the fetal lung may be controlled by upregulation of the EGF-R.

Pulse oximetry: what's normal in the newborn nursery?

The objective of this study was to establish normal values for pulse oximetry saturation (POS) in healthy newborn infants in the nursery. POS values were obtained from the right (R) hand and R foot at admission, 24 hr, and at discharge. The following information was recorded: postnatal age, activity state, gender, gestational age (GA), birth weight (BW), mode of delivery (MOD), and Apgar scores. Charts were reviewed and follow-up information was obtained for newborns with measurements < or =92%. The study group consisted of a convenience sample of newborn infants, excluding those on supplemental oxygen. Seven hundred eighteen patients were studied: 51% males, 28% cesarean sections, gestational age 39.3+/-1.6 weeks (mean +/- SD), birth weight 3370+/-550 g, and median Apgar scores 8 and 9. The mean POS was 97.2 +/-1.6%, and the median value was 97%. Only postnatal age and activity state affected POS significantly. POS increased 0.17% per 24 hr in the nursery (P = 0. 0001). POS values obtained while the infants were fussy and crying were lower compared to measurements obtained while sleeping [mean decreases: 0.44% while fussy (P = 0.001), 0.98% while crying (P = 0.0001)]. We conclude that newborns in the nursery have an overall mean POS of 97.2% (+/-2 SD: 94-100%). Mean POS values increase to a small degree with increasing postnatal age. Fussy and crying newborns have lower POS values compared to quiet and sleeping newborns. These reference data can be used in the evaluation of POS measurements in symptomatic newborn infants.

Effects of early inhaled beclomethasone therapy on tracheal aspirate inflammatory mediators IL-8 and IL-1ra in ventilated preterm infants at risk for bronchopulmonary dysplasia.

We tested the hypothesis that inhaled beclomethasone therapy for prevention of bronchopulmonary dysplasia (BPD) reduces pulmonary inflammation. As part of a randomized, placebo-controlled trial, interleukin-8 (IL-8) and interleukin-1 receptor antagonist (IL-1ra) concentrations in tracheal aspirates were measured as markers of pulmonary inflammation. On study days 1 (baseline), 8, 15, and day 28 of age, samples were obtained from enrolled infants (birth weights <1,251 g, gestational age <33 week, 3 to 14 days of age) who remained ventilated and had not received systemic glucocorticoid therapy. Cytokine levels (pg/microg of free secretory component of immunoglobulin A) were compared between groups. We determined whether baseline cytokine levels modified treatment effect regarding subsequent need for systemic glucocorticoid therapy or occurrence of BPD (age 28 days). Tracheal aspirates were obtained from 161 infants (77 receiving beclomethasone, 84 receiving placebo). Median IL-8 levels were lower in beclomethasone versus placebo infants on study days 8 (82.9 vs. 209.2, P < 0.01) and 15 (37.4 vs. 77.4, P < 0.03) after controlling for antenatal glucocorticoid therapy and maternal race. Median IL-1ra levels were lower in beclomethasone versus placebo infants only on study day 8 (86.5 vs. 153.3, P < 0.01). Fewer beclomethasone infants with baseline IL-8 levels in the interquartile range required systemic glucocorticoid therapy (beclomethasone 30.6% vs. placebo 65.8%, P < 0.01) or developed BPD (beclomethasone 42.4% vs. placebo 69.4%, P < 0.03). We conclude that early-inhaled beclomethasone therapy was associated with a reduction in pulmonary inflammation after 1 week of therapy. Beclomethasone-treated infants with moderately elevated baseline IL-8 levels received less subsequent systemic glucocorticoid therapy and had a lower incidence of BPD than nontreated infants.

Association of bronchopulmonary sequestration with expression of the homeobox protein Hoxb-5.

Bronchopulmonary sequestration (BPS) is caused by the abnormal development of an accessory lung diverticulum from the foregut very early in embryogenesis. The developmental abnormalities seen with BPS suggest that this anomaly is caused by abnormal expression of homeobox genes, which control axial identity and organ-specific patterning during embryogenesis. The authors previously have shown that the homeobox gene Hoxb-5 is necessary for normal airway branching during lung development. The authors now report that BPS is associated with aberrant developmental expression of Hoxb-5 protein, suggesting that this Hox gene is involved in the development of BPS.