Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 27
Filter
1.
BMC Pediatr ; 23(1): 573, 2023 11 17.
Article in English | MEDLINE | ID: mdl-37978460

ABSTRACT

BACKGROUND: Neonatal near-miss (NNM) can be considered as an end of a spectrum that includes stillbirths and neonatal deaths. Clinical audits of NNM might reduce perinatal adverse outcomes. The aim of this review is to evaluate the effectiveness of NNM audits for reducing perinatal mortality and morbidity and explore related contextual factors. METHODS: PubMed, Embase, Scopus, CINAHL, LILACS and SciELO were searched in February/2023. Randomized and observational studies of NNM clinical audits were included without restrictions on setting, publication date or language. PRIMARY OUTCOMES: perinatal mortality, morbidity and NNM. SECONDARY OUTCOMES: factors contributing to NNM and measures of quality of care. Study characteristics, methodological quality and outcome were extracted and assessed by two independent reviewers. Narrative synthesis was performed. RESULTS: Of 3081 titles and abstracts screened, 36 articles had full-text review. Two studies identified, rated, and classified contributing care factors and generated recommendations to improve the quality of care. No study reported the primary outcomes for the review (change in perinatal mortality, morbidity and NNM rates resulting from an audit process), thus precluding meta-analysis. Three studies were multidisciplinary NNM audits and were assessed for additional contextual factors. CONCLUSION: There was little data available to determine the effectiveness of clinical audits of NNM. While trials randomised at patient level to test our research question would be difficult or unethical for both NNM and perinatal death audits, other strategies such as large, well-designed before-and-after studies within services or comparisons between services could contribute evidence. This review supports a Call to Action for NNM audits. Adoption of formal audit methodology, standardised NNM definitions, evaluation of parent's engagement and measurement of the effectiveness of quality improvement cycles for improving outcomes are needed.


Subject(s)
Near Miss, Healthcare , Perinatal Death , Female , Humans , Infant, Newborn , Pregnancy , Clinical Audit , Perinatal Death/prevention & control , Perinatal Mortality , Stillbirth
2.
Resuscitation ; 191: 109934, 2023 10.
Article in English | MEDLINE | ID: mdl-37597649

ABSTRACT

AIM: To evaluate delivery room (DR) interventions to prevent hypothermia and improve outcomes in preterm newborn infants <34 weeks' gestation. METHODS: Medline, Embase, CINAHL and CENTRAL were searched till 22nd July 2022. Randomized controlled trials (RCTs), non-RCTs and quality improvement studies were considered. A random effects meta-analysis was performed, and the certainty of evidence was evaluated using GRADE guidelines. RESULTS: DR temperature of ≥23 °C compared to standard care improved temperature outcomes without an increased risk of hyperthermia (low certainty), whereas radiant warmer in servo mode compared to manual mode decreased mean body temperature (MBT) (moderate certainty). Use of a plastic bag or wrap (PBW) improved normothermia (low certainty), but with an increased risk of hyperthermia (moderate certainty). Plastic cap improved normothermia (moderate certainty) and when combined with PBW improved MBT (low certainty). Use of a cloth cap decreased moderate hypothermia (low certainty). Though thermal mattress (TM) improved MBT, it increased risk of hyperthermia (low certainty). Heated-humidified gases (HHG) for resuscitation decreased the risk of moderate hypothermia and severe intraventricular hemorrhage (very low to low certainty). None of the interventions was shown to improve survival, but sample sizes were insufficient. CONCLUSIONS: DR temperature of ≥23 °C, radiant warmer in manual mode, use of a PBW and a head covering is suggested for preterm newborn infants <34 weeks' gestation. HHG and TM could be considered in addition to PBW provided resources allow, in settings where hypothermia incidence is high. Careful monitoring to avoid hyperthermia is needed.


Subject(s)
Hypothermia , Infant, Premature, Diseases , Infant, Newborn , Infant , Humans , Pregnancy , Female , Hypothermia/prevention & control , Hypothermia/complications , Infant, Premature , Gestational Age , Resuscitation/adverse effects
3.
Resuscitation ; 180: 81-98, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36174764

ABSTRACT

AIM: Prevention of hypothermia after birth is a global problem in late preterm and term neonates. The aim of this systematic review and meta-analysis was to evaluate delivery room strategies to maintain normothermia and improve survival in late preterm and term neonates (≥34 weeks' gestation). METHODS: Medline, Embase, CINAHL, CENTRAL and international clinical trial registries were searched. Randomized controlled trials (RCTs), quasi-RCTs and observational studies were eligible for inclusion. Risk of bias for each study and GRADE certainty of evidence for each outcome were assessed. RESULTS: 25 RCTs and 10 non-RCTs were included. Room temperature of 23 °C compared to 20 °C improved normothermia [Risk Ratio (RR), 95% Confidence Interval (CI): 1.26, 1.11-1.42)] and body temperature [Mean Difference (MD), 95% CI: 0.30 °C, 0.23-0.37 °C), and decreased moderate hypothermia (RR, 95% CI: 0.26, 0.16-0.42). Skin to skin care (SSC) compared to no SSC increased body temperature (MD, 95% CI: 0.32, 0.10-0.52), reduced hypoglycemia (RR, 95% CI: 0.16, 0.05-0.53) and hospital admission (RR, 95% CI: 0.34, 0.14-0.83). Though plastic bag or wrap (PBW) alone or when combined with SSC compared to SSC alone improved temperatures, the risk-benefit balance is uncertain. Clinical benefit or harm could not be excluded for the primary outcome of survival for any of the interventions. Certainty of evidence was low to very low for all outcomes. CONCLUSIONS: Room temperature of 23 °C and SSC soon after birth may prevent hypothermia in late preterm and term neonates. Though PBW may be an effective adjunct intervention, the risk-benefit balance needs further investigation.

4.
Sci Rep ; 8(1): 15112, 2018 10 11.
Article in English | MEDLINE | ID: mdl-30310099

ABSTRACT

Neonates are exposed to microbes in utero and at birth, thereby establishing their microbiota (healthy microbial colonisers). Previously, we reported significant differences in the neonatal oral microbiota of breast-fed and formula-fed babies after first discovering a primal metabolic mechanism that occurs when breastmilk (containing the enzyme xanthine oxidase) and neonatal saliva (containing highly elevated concentrations of the substrates for xanthine oxidase: xanthine and hypoxanthine). The interaction of neonatal saliva and breast milk releases antibacterial compounds including hydrogen peroxide, and regulates the growth of bacteria. Using a novel in vitro experimental approach, the current study compared the effects of this unique metabolic pathway on a range of bacterial species and determined the period of time that microbial growth was affected. We demonstrated that microbial growth was inhibited predominately, immediately and for up to 24 hr following breastmilk and saliva mixing; however, some microorganisms were able to recover and continue to grow following exposure to these micromolar amounts of hydrogen peroxide. Interestingly, growth inhibition was independent of whether the organisms possessed a catalase enzyme. This study further confirms that this is one mechanism that contributes to the significant differences in the neonatal oral microbiota of breast-fed and formula-fed babies.


Subject(s)
Bacteria/growth & development , Microbiota , Milk, Human , Mouth/microbiology , Saliva , Adult , Female , Humans , Hydrogen Peroxide/pharmacology
5.
Transfus Med ; 28(2): 117-131, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29667253

ABSTRACT

Patient blood management (PBM) refers to an evidence-based package of care that aims to improve patient outcomes by optimal use of transfusion therapy, including managing anaemia, preventing blood loss and improving anaemia tolerance in surgical and other patients who may need transfusion. In adults, PBM programmes are well established, yet the definition and implementation of PBM in neonates and children lags behind. Neonates and infants are frequently transfused, yet they are often under-represented in transfusion trials. Adult PBM programmes may not be directly applicable to these populations. We review the literature in neonatal (and applicable paediatric) transfusion medicine and propose specific neonatal PBM definitions and elements.


Subject(s)
Anemia/therapy , Blood Loss, Surgical/prevention & control , Blood Transfusion/methods , Delivery of Health Care , Female , Humans , Infant , Infant, Newborn , Male
6.
J Perinatol ; 37(4): 387-393, 2017 04.
Article in English | MEDLINE | ID: mdl-28005065

ABSTRACT

OBJECTIVE: The International Liaison Committee on Resuscitation (ILCOR) provides recommendations on neonatal resuscitation training and practice, which includes a template for a decision-making algorithm. We evaluated the design properties of the ILCOR algorithm and four adaptations by member resuscitation organizations using the validated Cognitive Aids in Medicine Assessment Tool (CMAT). STUDY DESIGN: Two experts rated five neonatal resuscitation algorithms against the CMAT and against medical device design criteria. RESULTS: The ILCOR algorithm scored 32 of a possible 60 CMAT points, showing an adherence rate to CMAT of 53%. The ILCOR algorithm scored higher than the design variations by member organizations. Nonetheless, there are design limitations in the ILCOR algorithm. CONCLUSION: In principle, cognitive aids can improve neonatal resuscitation team performance; however, a considered design process that incorporates the full complexity of the 'procedure as performed' is needed to improve future versions of the algorithm for incorporation in international guidelines.


Subject(s)
Cardiopulmonary Resuscitation/standards , Cognition , Guideline Adherence/statistics & numerical data , Neonatology/standards , Algorithms , Cardiopulmonary Resuscitation/education , Humans , Infant, Newborn , Neonatology/education , Practice Guidelines as Topic
7.
Sci Rep ; 6: 38309, 2016 12 06.
Article in English | MEDLINE | ID: mdl-27922070

ABSTRACT

In utero and upon delivery, neonates are exposed to a wide array of microorganisms from various sources, including maternal bacteria. Prior studies have proposed that the mode of feeding shapes the gut microbiota and, subsequently the child's health. However, the effect of the mode of feeding and its influence on the development of the neonatal oral microbiota in early infancy has not yet been reported. The aim of this study was to compare the oral microbiota of healthy infants that were exclusively breast-fed or formula-fed using 16S-rRNA gene sequencing. We demonstrated that the oral bacterial communities were dominated by the phylum Firmicutes, in both groups. There was a higher prevalence of the phylum Bacteroidetes in the mouths of formula-fed infants than in breast-fed infants (p = 0.01), but in contrast Actinobacteria were more prevalent in breast-fed babies; Proteobacteria was more prevalent in saliva of breast-fed babies than in formula-fed neonates (p = 0.04). We also found evidence suggesting that the oral microbiota composition changed over time, particularly Streptococcus species, which had an increasing trend between 4-8 weeks in both groups. This study findings confirmed that the mode of feeding influences the development of oral microbiota, and this may have implications for long-term human health.


Subject(s)
Breast Feeding , Infant Formula/microbiology , Microbiota/genetics , Milk, Human/microbiology , Mouth/microbiology , Saliva/microbiology , Actinobacteria/classification , Actinobacteria/genetics , Actinobacteria/isolation & purification , Bacteroidetes/classification , Bacteroidetes/genetics , Bacteroidetes/isolation & purification , Female , Firmicutes/classification , Firmicutes/genetics , Firmicutes/isolation & purification , Gestational Age , High-Throughput Nucleotide Sequencing , Humans , Infant , Infant, Newborn , Male , Phylogeny , Proteobacteria/classification , Proteobacteria/genetics , Proteobacteria/isolation & purification , RNA, Ribosomal, 16S/genetics , Streptococcus/classification , Streptococcus/genetics , Streptococcus/isolation & purification
8.
Article in English | MEDLINE | ID: mdl-23792366

ABSTRACT

Saliva contains a number of biochemical components which may be useful for diagnosis/monitoring of metabolic disorders, and as markers of cancer or heart disease. Saliva collection is attractive as a non-invasive sampling method for infants and elderly patients. We present a method suitable for saliva collection from neonates. We have applied this technique for the determination of salivary nucleotide metabolites. Saliva was collected from 10 healthy neonates using washed cotton swabs, and directly from 10 adults. Two methods for saliva extraction from oral swabs were evaluated. The analytes were then separated using high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS). The limits of detection for 14 purine/pyrimidine metabolites were variable, ranging from 0.01 to 1.0µM. Recovery of hydrophobic purine/pyrimidine metabolites from cotton tips was consistently high using water/acetonitrile extraction (92.7-111%) compared with water extraction alone. The concentrations of these metabolites were significantly higher in neonatal saliva than in adults. Preliminary ranges for nucleotide metabolites in neonatal and adult saliva are reported. Hypoxanthine and xanthine were grossly raised in neonates (49.3±25.4; 30.9±19.5µM respectively) compared to adults (4.3±3.3; 4.6±4.5µM); nucleosides were also markedly raised in neonates. This study focuses on three essential details: contamination of oral swabs during manufacturing and how to overcome this; weighing swabs to accurately measure small saliva volumes; and methods for extracting saliva metabolites of interest from cotton swabs. A method is described for determining nucleotide metabolites using HPLC with photodiode array or MS/MS. The advantages of utilising saliva are highlighted. Nucleotide metabolites were not simply in equilibrium with plasma, but may be actively secreted into saliva, and this process is more active in neonates than adults.


Subject(s)
Chromatography, High Pressure Liquid/methods , Nucleotides/analysis , Purines/analysis , Pyrimidines/analysis , Saliva/chemistry , Tandem Mass Spectrometry/methods , Adult , Female , Humans , Infant, Newborn , Limit of Detection , Linear Models , Male , Middle Aged , Nucleotides/metabolism , Reproducibility of Results
9.
Eur J Clin Microbiol Infect Dis ; 29(10): 1311-4, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20549528

ABSTRACT

The purpose of this brief report is to describe the first outbreak of a community-associated nonmultiresistant and PVL-positive MRSA strain (CC30) in a neonatal intensive care unit in Australia. The utility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) for microbial typing is compared with single nucleotide polymorphism (SNP) plus binary gene analysis. The composite correlation index analysis of the MALDI-TOF-MS data demonstrated the similar inter-strain relatedness found with the SNP-plus-binary gene typing used to confirm the outbreak. The evolving spread of MRSA emphasizes the importance of surveillance, infection control vigilance and the ongoing investigation of rapid typing methods for MRSA.


Subject(s)
Bacterial Toxins/biosynthesis , Bacterial Typing Techniques/methods , Community-Acquired Infections/epidemiology , Disease Outbreaks , Exotoxins/biosynthesis , Leukocidins/biosynthesis , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Staphylococcal Infections/epidemiology , Australia/epidemiology , Community-Acquired Infections/microbiology , DNA Fingerprinting/methods , Drug Resistance, Bacterial , Genotype , Humans , Infant , Intensive Care Units, Neonatal , Male , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/pathogenicity , Molecular Epidemiology/methods , Polymorphism, Single Nucleotide , Staphylococcal Infections/microbiology
10.
Cochrane Database Syst Rev ; (3): CD004452, 2005 Jul 20.
Article in English | MEDLINE | ID: mdl-16034931

ABSTRACT

BACKGROUND: Preterm birth, defined as birth before 37 completed weeks, is the single most important cause of perinatal mortality and morbidity in high-income countries. Oxytocin receptor antagonists have been proposed as effective tocolytic agents for women in preterm labour to postpone the birth, with fewer side-effects than other tocolytic agents. OBJECTIVES: To assess the effects on maternal, fetal and neonatal outcomes of tocolysis with oxytocin receptor antagonists for women with preterm labour compared with placebo or no intervention and compared with any other tocolytic agent. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2004), CENTRAL (The Cochrane Library, Issue 3, 2004), MEDLINE (1965 to June 2004), EMBASE (1988 to June 2004). SELECTION CRITERIA: Randomised trials of oxytocin receptor antagonists for tocolysis in the management of women in labour between 20 and 36 weeks' gestation. DATA COLLECTION AND ANALYSIS: Two authors independently evaluated methodological quality and extracted trial data. We sought additional information from trial authors. MAIN RESULTS: Six trials (1695 women) were included. Compared with placebo, atosiban did not reduce incidence of preterm birth or improve neonatal outcome. In one trial (583 infants), atosiban was associated with an increase in infant deaths at 12 months of age compared with placebo (relative risk (RR) 6.15; 95% confidence intervals (CI) 1.39 to 27.22). However, this trial randomised significantly more women to atosiban before 26 weeks' gestation. Use of atosiban resulted in lower infant birthweight (weighted mean difference -138.31 gm; 95% CI -248.76 to -27.86) and more maternal adverse drug reactions (RR 4.02; 95% CI 2.05 to 7.85, 2 trials, 613 women).Compared with betamimetics, atosiban increased the numbers of infants born under 1500 gm (RR 1.96; 95% CI 1.15 to 3.35, 2 trials, 575 infants). Atosiban was associated with fewer maternal drug reactions requiring treatment cessation (RR 0.04; 95% CI 0.02 to 0.11, number needed to treat 6; 95% CI 5 to 7, 4 trials, 1035 women). AUTHORS' CONCLUSIONS: This review failed to demonstrate the superiority of atosiban over betamimetics or placebo in terms of tocolytic efficacy or infant outcomes. The finding of an increase in infant deaths in one placebo controlled trial warrants caution. A recent Cochrane review suggests that calcium channel blockers (mainly nifedipine) are associated with better neonatal outcome and fewer maternal side-effects than betamimetics. However, a randomised comparison of nifedipine with placebo is not available. Further well-designed randomised controlled trials of tocolytic therapy are needed. Such trials should incorporate a placebo arm.


Subject(s)
Obstetric Labor, Premature/drug therapy , Receptors, Oxytocin/antagonists & inhibitors , Tocolytic Agents/therapeutic use , Albuterol/therapeutic use , Female , Humans , Pregnancy , Randomized Controlled Trials as Topic , Ritodrine/therapeutic use , Terbutaline/therapeutic use , Vasotocin/adverse effects , Vasotocin/analogs & derivatives , Vasotocin/therapeutic use
12.
Curr Drug Targets ; 5(1): 89-105, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14738220

ABSTRACT

Vaccines have been described as "weapons of mass protection". The eradication of many diseases is testament to their utility and effectiveness. Nevertheless, many vaccine preventable diseases remain prevalent because of political and economic barriers. Additionally, the effects of immaturity and old age, therapies that incapacitate the adaptive immune system and the multitude of strategies evolved by pathogens to evade immediate or sustained recognition by the mammalian immune system are barriers to the effectiveness of existing vaccines or development of new vaccines. In the front line of defence against the pervasiness of infection are the elements of the innate immune system. Innate immunity is under studied and poorly appreciated. However, in the first days after entry of a pathogen into the body, our entire protective response is dependant upon the various elements of our innate immune repertoire. In spite of its place as our initial defence against infection, attention is only now turning to strategies which enhance or supplement innate immunity. This review examines the need for and potential of innate immune therapies.


Subject(s)
Immunity, Innate , Vaccines/immunology , Humans , Immunotherapy , Infection Control , Infections/epidemiology , Infections/immunology , Infections/therapy
13.
Cochrane Database Syst Rev ; (3): CD003313, 2002.
Article in English | MEDLINE | ID: mdl-12137687

ABSTRACT

BACKGROUND: Exchange transfusion and phototherapy have traditionally been used to treat jaundice and avoid the associated neurological complications. Exchange transfusion is not without risk and intravenous immunoglobulin has been suggested as an alternative therapy for isoimmune haemolytic jaundice to reduce the need for exchange transfusion. OBJECTIVES: To assess whether the use of intravenous immunoglobulin, in newborn infants with isoimmune haemolytic jaundice, is effective in reducing the need for exchange transfusion. SEARCH STRATEGY: The search strategy of the Cochrane Neonatal Review group was used. Searches were made of MEDLINE 1966-2002, EMBASE Drugs and Pharmacology 1990-2002, Cochrane Controlled Trials Register, The Cochrane Library, Issue 1, 2002, expert informants, review articles, cross references, and hand searching of abstracts and conference proceedings of the annual meetings of The Society for Pediatric Research 1990-2001 and The European Society for Paediatric Research 1990-2001. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials of the use of intravenous immunoglobulin in the treatment of isoimmune haemolytic disease were considered. DATA COLLECTION AND ANALYSIS: The standard methods of the Cochrane Collaboration and its Neonatal Review Group were used. Studies were assessed for inclusion and quality by two reviewers working independently, with the second reviewer blinded to trial author, institution and journal of publication. Data were extracted independently by the two reviewers. Any differences of opinion were discussed and a consensus reached. Investigators were contacted for additional or missing information. For categorical outcomes, the relative risk (RR), risk difference (RD) and the number needed to treat (NNT) were calculated. For continuous variables, the weighted mean difference (WMD) was calculated. MAIN RESULTS: Seven studies were identified. Three of these fulfilled the inclusion criteria and included a total of 189 infants. Term and preterm infants and infants with rhesus and ABO incompatibility were included. The use of exchange transfusion decreased significantly in the immunoglobulin treated group (typical RR 0.28, 95% CI 0.17, 0.47; typical RD -0.37, 95% CI -0.49, -0.26; NNT 2.7). The mean number of exchange transfusions per infant was also significantly lower in the immunoglobulin treated group (WMD -0.52, 95% CI -0.70, -0.35). None of the studies assessed long term outcomes. REVIEWER'S CONCLUSIONS: Although the results show a significant reduction in the need for exchange transfusion in those treated with intravenous immunoglobulin, the applicability of the results is limited. The number of studies and infants included is small and none of the three included studies was of high quality. The protocols of two of the studies mandated the use of early exchange transfusion, limiting the generalizability of the results. Further well designed studies are needed before routine use of intravenous immunoglobulin can be recommended for the treatment of isoimmune haemolytic jaundice.


Subject(s)
Anemia, Hemolytic/therapy , Anemia, Neonatal/therapy , Immunoglobulins, Intravenous , Jaundice, Neonatal/therapy , Anemia, Hemolytic/immunology , Anemia, Neonatal/immunology , Humans , Infant, Newborn , Jaundice, Neonatal/immunology , Randomized Controlled Trials as Topic
16.
Exp Cell Res ; 224(1): 116-22, 1996 Apr 10.
Article in English | MEDLINE | ID: mdl-8612675

ABSTRACT

Extracellular matrix (ECM) molecules, such as fibronectin (FN), regulate fibroblast sensitivity to soluble growth factors, in part, by controlling cellular levels of phosphatidylinositol bis-phosphate (PIP2), the substrate for phospholipase C-gamma (McNamee et al., 1993, J. Cell Biol. 121, 673-678). In the present study, we extended these investigations by exploring whether cells of the vascular wall also exhibit this response and analyzing the mechanism by which adhesion to ECM regulates intracellular PIP2 mass. Capillary endothelial cells, pulmonary vascular smooth muscle cells, and C3H 101/2 fibroblasts were all found to exhibit a similar two- to threefold increase in PIP2 mass within 3 h after binding to dishes coated with FN. Furthermore, similar effects were observed using dishes coated with a variety of different ECM molecules, including collagen types I and IV as well as a synthetic RGD-containing peptide. An increase in PIP2 mass also was produced when suspended cells bound to microbeads (4.5 micron diameter; coated with RGD-peptide or anti-integrin beta 1 antibody) that induce local integrin clustering and focal adhesion formation, independently of cell spreading. In contrast, neither binding of soluble FN nor binding of microbeads coated with ligands for other transmembrane surface receptors (e.g., acetylated low-density lipoprotein, antibodies against heparan sulfate) had any effect on PIP2 mass. While these results suggest that integrin clustering stimulates PIP2 synthesis, no change in total cellular or cytoskeletal-associated phosphatidylinositol-4-phosphate kinase (PIP kinase) activity could be detected when cells bound to immobilized integrin ligands. However, when focal adhesion complexes were isolated from these cells using a magnetic procedure (G. Plopper and D. E. Ingber, 1993, Biochem. Biophys. Res. Commun. 193, 571-578), this subfraction of the cytoskeleton was found to be enriched for PIP kinase activity by more than twofold relative to the whole cytoskeleton. These data suggest that ECM binding may increase PIP2 mass in vascular cells by clustering cell surface integrin receptors and activating cytoskeletal-associated PIP kinases locally within the focal adhesion complex.


Subject(s)
Endothelium, Vascular/growth & development , Integrin beta1/metabolism , Muscle Development , Muscle, Smooth/growth & development , Phosphatidylinositol Phosphates/biosynthesis , Signal Transduction , Animals , Cattle , Cell Adhesion , Endothelium, Vascular/cytology , Extracellular Matrix Proteins/metabolism , Mice , Muscle, Smooth/cytology , Phosphatidylinositol 4,5-Diphosphate
17.
Pediatr Res ; 38(5): 668-75, 1995 Nov.
Article in English | MEDLINE | ID: mdl-8552432

ABSTRACT

Pulmonary surfactant protein B (SP-B) enhances phospholipid film formation in vitro and is essential for normal surfactant function in vivo. We examined human fetal lung before and during explant culture for content and cellular localization of SP-B mRNA and protein. SP-B mRNA was low in preculture specimens (18-20 wk) but hybridization signal increased over epithelial cells during culture and was enhanced by dexamethasone treatment (10 nM). SP-B immunofluorescence was very low in preculture specimens, increased during culture, and was uniformly intense in epithelial cells of dexamethasone-treated tissue. With a newly developed immunoassay, SP-B protein was undetectable in preculture lung (< 2% of adult), appeared during culture (26% of adult), and was further increased approximately 3-fold by dexamethasone treatment (86% of adult); lung tissue of two newborn infants contained 7-9-fold more SP-B than is found in the adult. Using Western blot with enhanced chemiluminescence, mature SP-B was undetectable in 16-wk specimens but was present in 19-24-wk preculture tissue at 0.2-2.9% of the adult level. By comparison, SP-B mRNA content is 14 and 50% of adult level in 19- and 24-wk lung tissue, respectively; levels increase 3-fold during culture and a further 3-fold with dexamethasone. Based on these observed differences between mRNA and protein content, we conclude that basal SP-B gene expression in epithelial cells of human fetal lung is regulated primarily at the level of translation or protein stability, whereas glucocorticoids act transcriptionally. We speculate that SP-B protein accumulates only as type II cells differentiate and acquire lamellar bodies for processing and storage of SP-B.


Subject(s)
Dexamethasone/pharmacology , Lung/metabolism , Proteolipids/metabolism , Pulmonary Surfactants/metabolism , Adult , Blotting, Western , Glucocorticoids/pharmacology , Humans , Immunoblotting , In Situ Hybridization , Lung/embryology , Lung/surgery , Proteolipids/genetics , Pulmonary Surfactants/genetics , RNA, Messenger , Staining and Labeling
20.
Am J Respir Cell Mol Biol ; 2(2): 137-43, 1990 Feb.
Article in English | MEDLINE | ID: mdl-2106332

ABSTRACT

We examined the effects of interferon-gamma (IFN-gamma) on development of the surfactant system in alveolar epithelial cells of fetal lung. Explants of second-trimester human fetal lung were cultured for 1 to 6 days in serum-free medium containing recombinant human IFN-gamma (0.03 to 30 ng/ml) and/or dexamethasone (10 or 100 nM). Treatment for 3 days with IFN-gamma alone, dexamethasone alone, and IFN plus dexamethasone increased the content of surfactant protein A (SP-A, 28 to 36 kD) by approximately 3-, 2.5-, and 10-fold, respectively. The biphasic response pattern of SP-A to dexamethasone (stimulation initially and inhibition with continued culture) was not altered by the presence of IFN-gamma. IFN-gamma also stimulated accumulation of SP-A mRNA (2.7-fold at 24 h) but did not affect the levels of mRNAs for surfactant protein B (18 kD) and surfactant protein C (5 kD). To assess the effect of IFN-gamma on synthesis of surfactant lipids, we determined the content of phosphatidylcholine, the rate of labeled choline incorporation into phosphatidylcholine, saturation of newly synthesized phosphatidylcholine, and the activity of fatty acid synthetase, a glucocorticoid-inducible enzyme. Treatment of explants for 5 days with IFN-gamma had no effect on these parameters. Studies by light and electron microscopy revealed little difference between control and IFN-treated explants with regard to cell viability and epithelial cell differentiation. We conclude that IFN-gamma has a selective stimulatory effect on SP-A among surfactant components.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Interferon-gamma/pharmacology , Proteolipids/biosynthesis , Pulmonary Alveoli/metabolism , Pulmonary Surfactants/biosynthesis , Choline/metabolism , Culture Techniques , Dexamethasone/pharmacology , Fatty Acid Synthases/metabolism , Humans , Microscopy, Electron , Phosphatidylcholines/biosynthesis , Proteolipids/genetics , Pulmonary Alveoli/drug effects , Pulmonary Alveoli/embryology , Pulmonary Alveoli/ultrastructure , Pulmonary Surfactant-Associated Protein A , Pulmonary Surfactant-Associated Proteins , Pulmonary Surfactants/genetics , RNA, Messenger/analysis , Recombinant Proteins , Time Factors
SELECTION OF CITATIONS
SEARCH DETAIL
...