Nonlinearity of respiratory mechanics during bronchoconstriction in mice with airway inflammation.

Respiratory system resistance (R) and elastance (E) are commonly estimated by fitting the linear equation of motion P = EV + RV + P0 (Eq. 1) to measurements of respiratory pressure (P), lung volume (V), and flow (V). However, the respiratory system is unlikely to behave linearly under many circumstances.

Rapid activation of nuclear factor-kappaB in airway epithelium in a murine model of allergic airway inflammation.

Bronchiolar epithelium is postulated to play a critical role in the orchestration of responses to inhaled allergens, and may contribute to the pathogenesis of asthma. Using a murine model of allergic airway inflammation and hyperresponsiveness, we demonstrate in mice sensitized with ovalbumin (OVA) that following a single challenge with nebulized OVA, a rapid and protracted activation of inhibitor of kappa B kinase (IKK) occurred in lung tissue. IKK activation was followed by nuclear localization of nuclear factor (NF)-kappaB within the bronchiolar epithelium and increased luciferase activity in lungs of mice containing a NF-kappaB-dependent reporter gene.

Strain dependence of airway hyperresponsiveness reflects differences in eosinophil localization in the lung.

Different strains of mice exhibit different degrees of airway hyperresponsiveness after sensitization to and airway challenge with ovalbumin. Antibody responses in BALB/c mice far exceeded those in C57BL/6 mice; in contrast, although responsiveness to methacholine was much higher in the BALB/c mice, the number of eosinophils in the bronchoalveolar lavage fluid was higher in C57BL/6 animals. Sensitized and challenged BALB/c mice developed increases in lung resistance and decreases in dynamic compliance after methacholine or 5-hydroxytryptamine inhalation.

Distal lung dysfunction at night in nocturnal asthma.

We have previously shown that patients with nocturnal worsening of asthma (nocturnal asthma) exhibit increased parenchymal inflammation at night. To evaluate the functional significance of this parenchymal inflammation, 10 subjects with nocturnal asthma (NA), four subjects with non-nocturnal asthma (NNA), and four normal control subjects underwent bronchoscopy with measurement of peripheral airways resistance (Rp) at 4:00 P.M.

Airway responses to a diluent used in the methacholine challenge test.

Background: Inhalation of diluent is often used in performing methacholine challenge tests, but its elimination has been suggested because marked falls in FEV1 after diluent inhalation have not been documented and performing this step is time-consuming.

Objective: We investigated the frequency and magnitude of response to the inhalation of diluent, and if there were any systematic effects in determining the PC20 using the baseline and postdiluent spirometric measurements.

Methods: All methacholine challenges performed during a 6-year period (N = 3,902) were reviewed retrospectively.

Central line mechanical complication rate in emergency medicine patients.

Unlabelled: Central line (CL) placement in the emergency department (ED) is a common practice. Previously published small-scale studies have quoted mechanical complication rates in emergency medicine patients of 10-15%.

Objective: To determine the mechanical complication rate of central venous catheterization in a large (65,000 visits/year) academic urban ED.

Overexpression of tumor necrosis factor-alpha produces an increase in lung volumes and pulmonary hypertension.

Tumor necrosis factor (TNF)-alpha is a key proinflammatory cytokine that is thought to be important in the development of pulmonary fibrosis, whereas its role in pulmonary emphysema has not been as thoroughly documented. In the present study, TNF-alpha was overexpressed in alveolar type II cells under the control of the human surfactant protein C promoter. In this report, we further characterized the pulmonary abnormalities and provided a physiological assessment of these mice.

Compliance with emergency department prior authorization requirements under EMTALA.

Published in: Ann Emerg Med. 1999; 34(4 pt 2):S70.

Retrospective evaluation of potential medicare admission denials using interqual and millman and roberts admission criteria.

Published in: Acad Emerg Med. 2000; 7: 543.

Accuracy of interqual criteria in determining the hospitalization need in medicare patients with gastrointestinal bleeding.

Published in: Acad Emerg Med. 2000; 7: 552-3.

Timing of administration of anti-VLA-4 differentiates airway hyperresponsiveness in the central and peripheral airways in mice.

The development of airway hyperresponsiveness (AHR) is correlated with the infiltration into the lungs of activated eosinophils and T lymphocytes. In large part, influx of eosinophils into the lung is dependent on very late activating antigen-4 (VLA-4) expression. However, the kinetics of eosinophil recruitment and the development of AHR are not fully delineated.

Effects of cool, dry air stimulation on peripheral lung mechanics in asthma.

We have previously demonstrated that peripheral airway resistance (Rp) rises more in asthmatics than in nonasthmatic control subjects after segmental challenge with cool, dry air. To better understand this rise in Rp, we used a stop-flow method to measure the decay of segment pressure with time that yielded information on airway resistance (Raw), final plateau pressure (Pp), and peripheral lung compliance (Cp). After stop-flow maneuvers in all seven asthmatics and all seven normal subjects, pressure decayed smoothly without an initial sudden drop.

Smooth muscle cell matrix metalloproteinase production is stimulated via alpha(v)beta(3) integrin.

This study tests the hypothesis that alpha(v)beta(3) integrin receptors play a critical role in smooth muscle cell (SMC) migration after arterial injury and facilitate migration through the upregulation of matrix metalloproteinase (MMP) activity. We showed that beta(3) integrin mRNA was upregulated by SMCs in the balloon-injured rat carotid artery in coincidence with MMP-1 expression and early SMC migration. Treatment with the beta(3) integrin-blocking antibody F11 significantly decreased SMC migration into the intima at 4 days after injury, from 110.

CD23 exhibits negative regulatory effects on allergic sensitization and airway hyperresponsiveness.

The effects of an anti-CD23 monoclonal antibody (B3B4) in CD23-deficient and CD23-overexpressing mice were compared in a murine model of allergic sensitization. After sensitization and challenge with OA, mice developed increased serum levels of OA-specific IgE and IgG(1) with airway eosinophilia and AHR when compared with nonsensitized animals. Anti-CD23 treatment was studied under two protocols: 10-d OA aerosol exposure and intraperitoneal sensitization followed by aerosol challenge.

Reimbursement impact of medicaid managed care organizations replacing standard medicaid.

Study Objective: To evaluate the reimbursement difference for Medicaid managed care organization (MMCO) enrollees compared with Medicaid enrollees for emergency department patients with disease conditions that appear to meet the "prudent layperson" definition of an emergency medical condition.

Methods: This study used a retrospective reimbursement review of computerized billing data of reimbursement denials for 4 procedures (using Current Procedural Terminology codes for endotracheal intubation, cardiopulmonary resuscitation, central line placement, and lumbar puncture) and 1 International Classification of Diseases, ninth revision condition (chest pain) on MMCO patients from 7 MMCOs compared with standard Medicaid patients presenting to 4 EDs during a 6-month period (January through June 1998). Exclusion criteria were late bills that did not allow at least 90 days for payment and bills submitted on behalf of patients that were not covered at the time of service by Medicaid or MMCO.

Effect of a state definition of an "emergency medical condition" legislation on medicaid managed care organization reimbursement.

Study Objective: The state of Michigan passed Public Act 136 of 1997 requiring Medicaid managed care organizations (MMCOs) to pay for emergency services whenever presenting symptoms constituted an "emergency medical condition." The objective of this study was to evaluate MMCO reimbursement before and after enactment of this state law.

Methods: We conducted a retrospective comparison of reimbursement for lacerations needing repair (identified using Current Procedural Terminology codes from computerized billing data) for 2 time periods (before the state law was applicable [January through March 1998] and after the state law was applicable [April through June 1998]) from MMCO enrollees in 7 different MMCOs presenting to 4 urban emergency departments.

The invaluable pressure-volume curve.

We present a case in which the pressure-volume (P-V) curve proved invaluable in the diagnostic workup of a patient. The patient was a 43-year-old man who presented with progressive dyspnea on exertion, restrictive spirometry, exercise desaturation, and an unremarkable CT scan. Because of the unexpected finding of an unremarkable CT scan, we wanted more data assuring the presence of an indication for lung biopsy.

Interaction between the growing lung and asthma: role of early intervention.

Asthma is a syndrome where an imbalance exists between the forces that maintain airway patency and the forces that act to narrow, or close, airways. The child with asthma is a particular problem because of the rapid growth of the lung during growth that leaves it vulnerable. There is some evidence that asthma leads to impaired lung function in children because those children with untreated asthma show a loss of lung growth velocity.

Airway-parenchyma uncoupling in nocturnal asthma.

Airway flow resistance is well known to be dependent upon lung volume. The rise in lung volume that occurs in asthma is therefore thought to be an important mechanism that defends airway patency. The purpose of the current study was to investigate the interdependence or mechanical coupling between airways and lung parenchyma during the inflammatory processes that occur in the patient with nocturnal asthma.

The pharmacology of aerosolized airway challenge.

Clinicians who perform and interpret airway challenge tests must understand the pharmacology involved. This knowledge helps one appreciate the need for certain procedures and the importance of proper technique. Methacholine and histamine are the most commonly used airway challenge agents.

Development of eosinophilic airway inflammation and airway hyperresponsiveness requires interleukin-5 but not immunoglobulin E or B lymphocytes.

We previously defined a role for B cells and allergen-specific immunoglobulins in the development of allergic sensitization, airway inflammation, and airway hyperresponsiveness (AHR), using a 10-d protocol in which allergen exposure occurred exclusively via the airways, without adjuvant. In the present protocol, normal and B-cell-deficient (microMt(-/-)) mice were sensitized intraperitoneally to ovalbumin (OVA) and challenged with OVA via the airways in order to examine the requirements for AHR with this protocol. T-cell activation (antigen-specific proliferative responses and Th2-type cytokine production) and eosinophil infiltration in the peribronchial regions of the airways, with signs of eosinophil activation and degranulation, occurred in both experimental groups.

The late, but not early, asthmatic response is dependent on IL-5 and correlates with eosinophil infiltration.

Early-phase reactions (EPRs) and late-phase reactions (LPRs) are characteristic features of bronchial asthma, although the pathogenetic mechanisms responsible for each of the responses are not fully defined. A murine model of EPRs and LPRs was developed to investigate the role of IL-5 and eosinophils in development of both responses. After initial intraperitoneal sensitization and airway challenge to ovalbumin (OVA), mice were provoked by additional exposure to OVA.

Access for low-income children: is health insurance enough?

Objective: The Balanced Budget Act of 1997 authorizes $20 billion for states to expand health insurance coverage among uninsured low-income children. This study identifies lessons learned from the Medicaid Extension Demonstration, which was authorized by Congress to experiment with innovative approaches to providing health care coverage for low-income children. The three programs compare and contrast a variety of features that may enhance or detract from access, including a traditional Medicaid expansion, a private indemnity model, and a comprehensive managed care delivery system.