Nitric oxide regulates interleukin-8 gene expression in activated endothelium by inhibiting NF-kappaB binding to DNA: effects on endothelial function.

Nuclear factor-kappaB (NF-kappaB) binds to nucleotide sequences between -80 and -70 bp upstream of the transcriptional start site in the interleukin-8 (IL-8) promoter and is crucial for transcription of the IL-8 gene. We showed that exogenous nitric oxide in the form of a nitric oxide donor significantly reduced IL-8 mRNA in cytokine-activated ECV304. Similarly, nitric oxide significantly reduced migration of polymorphonuclear neutrophils through cytokine-activated ECV304 monolayers, an IL-8-dependent process. Using a luciferase reporter construct containing the NF-kappaB site of the IL-8 gene, we showed that exposing cytokine-activated ECV304 to exogenous nitric oxide resulted in significant reduction of NF-kappaB binding. Follow-up studies using a luciferase reporter construct possessing a mutated NF-kappaB site confirmed that the luciferase activity observed in the NF-kappaB reporter resulted from NF-kappaB binding. These studies demonstrate that nitric oxide, supplied exogenously into reactions containing activated endothelium, down-regulates pro-inflammatory activity, such as the secretion of chemokines, and functional activity, such as transendothelial migration of neutrophils.

Delayed administration of inhaled nitric oxide preserves alveolar-capillary membrane integrity in porcine gram-negative sepsis.

OBJECTIVE: To determine the effect of delayed administration of inhaled nitric oxide (NO) on acute lung injury after the onset of gram-negative sepsis. DESIGN: Nonrandomized controlled study. SETTING: University medical center laboratory. SUBJECTS: Yorkshire swine. INTERVENTIONS: Five groups of swine were anesthetized, mechanically ventilated, and studied for 5 hours. After surgical preparation, control (n = 10) and NO-treated control (n = 6) animals received a 1-hour infusion of sterile saline solution. Sepsis was induced with a 1-hour intravenous infusion of live Pseudomonas aeruginosa. Untreated animals with sepsis (n = 10) received no treatment. Inhaled NO at 20 ppm was administered to NO30-treated animals with sepsis (n = 7) and NO60-treated animals with sepsis (n = 8) beginning at 30 and 60 minutes after bacterial infusion was begun, respectively. MAIN OUTCOME MEASURES: Systemic and pulmonary hemodynamics, arterial blood gas determination, bronchoalveolar lavage protein and neutrophil content, neutrophil oxidant burst, lung myeloperoxidase content, and scanning electron micrographic studies. RESULTS: A progressive, significant (P < .05) decline in PaO2 developed in untreated animals with sepsis, which was prevented in NO30- and NO60-treated animals with sepsis. A significant (P < .05) increase in bronchoalveolar lavage protein and neutrophil counts compared with baseline values was observed in untreated animals with sepsis, indicating acute lung injury. These variables exhibited no notable increase in NO30- and NO60-treated animals with sepsis and were significantly (P < .05) reduced compared with untreated animals with sepsis. The lung myeloperoxidase content was significantly (P < .05) elevated at 5 hours in all groups with sepsis compared with baseline values and the control and NO-treated control groups. The total phorbol myristate acetate-induced polymorphonuclear leukocyte oxidant burst at 5 hours was significantly (P < .05) decreased in the NO30- and NO60-treated animals with sepsis compared with untreated animals with sepsis. Untreated and NO30- and NO60-treated animals with sepsis showed a significant (P < .05) increase in pulmonary artery pressure at 30 minutes, followed by a progressive decline. These changes were significant (P < .05) compared with baseline values and the control groups. No significant (P < .05) difference in pulmonary artery pressure or systemic arterial pressure was found at any time between untreated and NO30- and NO60-treated animals with sepsis. CONCLUSIONS: The delayed administration of inhaled NO preserves alveolar-capillary membrane integrity in this porcine model of gram-negative sepsis. The inhibition of neutrophil transendothelial migration, rather than neutrophil rolling or tight adhesion, may be a critical mechanism by which inhaled NO produces this effect. Decreased oxidant production by activated neutrophils may be a secondary mechanism by which inhaled NO reduces acute lung injury.

Infantile apnea monitoring and SIDS.

Primary care practitioners are presented with many concerns and questions from families about Sudden Infant Death Syndrome (SIDS), apnea, and monitors. Clinicians need to know which symptoms are of concern, when to ask for consultation from an apnea center, and how to refer the parent for support and counseling. This article reviews the current knowledge of infantile apnea, monitoring, and SIDS. An approach to evaluation and management is presented.

Apnea of infancy--a clinical problem.

Of 569 infants referred to the Children's Orthopedic Hospital and Medical Center Apnea Program (Seattle) for evaluation between 1978 and 1983, a total of 232 were discharged with cardiopulmonary monitors. Of these, 164 (71%) were at 38 weeks' gestation or more (term). In all, 203 (88%) presented with an episode in which vigorous stimulation or resuscitation was used to terminate the event. The mean age of the infants at first episode was 43 days. In 226 (97%) of the infants there was resolution of apnea symptoms by 1 year of age. During this interval, five infants died. Those infants who presented with severe episodes continued to have severe episodes at home and had a longer mean duration of monitoring than those presenting with milder symptoms.