Asthma: prevalence, pathogenesis, and prospects for novel therapies

Inhibiting ATG5 mediated autophagy to regulate endoplasmic reticulum stress and CD4+ T lymphocyte differentiation: Mechanisms of acupuncture's effects on asthma

OBJECTIVE

Asthma is characterized by airway hyperresponsiveness(AHR), inflammation and remodeling. Autophagy and endoplasmic reticulum stress(ERS) are dysregulated in asthma, and ATG5 has attracted wide attentions a representative gene of autophagy. Previous evidence shows that acupuncture may treat asthma by regulating the immune environment.However,the precise mechanism involved in acupuncture's effects on asthma is unclear. Thus, we investigated the inner-relationships of acupuncture and ATG5-mediated autophagy, ERS and CD4+ T lymphocyte differentiation in asthma.

METHODS

Ovalbumin (OVA)-sensitized and challenged ATG5+/- and ATG5-/-mice with asthma were treated by acupuncture at Dazhui(GV14),Feishu(BL13) and Zusanli(ST36),and sacrificed the next day.Then blood and bronchoalveolar lavage fluid (BALF)samples were collected to determine inflammatory cell counts and cytokine levels. Lung tissue samples were obtained for histological examination, and the spleen was harvested for flow cytometry.

RESULTS

Compared with the untreated group, acupuncture decreased BALF inflammatory cell counts and AHR in OVA-induced mice.Acupuncture decreased autophagy-related protein and mRNA (ATG5,Beclin-1,p62 and LC3B)amounts and ERS-related protein (p-PERK, p-IRE-1,Grp78, and ATF6)levels as well as autophagosome formation in lung tissue, concomitant with increased IFN-γ and decreased IL-4, IL-17 and TGF-β amounts in BALF.Consistently, the imbalance of CD4+ T lymphocyte subsets(Th1/Th2 and Treg/Th17) was also corrected by acupuncture.Meanwhile, AHR and inflammation were decreased in ATG5-/- mice compared with ATG+/-animals,without affecting the therapeutic effect of acupuncture.

CONCLUSION

Acupuncture reduces airway inflammation and AHR in asthma by inhibiting ATG5-mediated autophagy to regulate endoplasmic reticulum stress and CD4+T lymphocyte differentiation.

Transcriptome analysis in Takifugu rubripes and Dicentrarchus labrax gills during Cryptocaryon irritans infection

Takifugu rubripes and Dicentrarchus labrax are important commercial fish in China that are under serious threat from Cryptocaryon irritans. C. irritans is a ciliated obligate parasite that causes marine white spot disease and leads to heavy economic losses. We analysed the transcriptome in the gills of T. rubripes and D. labrax to compare differentially expressed genes (DEGs) and pathways during infection with C. irritans. In total, we identified 6,901 and 35,736 DEGs from T. rubripes and D. labrax, respectively. All DEGs were annotated into GO terms; 6,901 DEGs from T. rubripes were assigned into 991 sub-categories, and 35,736 DEGs from D. labrax were assigned into 8,517 sub-categories. We mapped DEGs to the KEGG database and obtained 153 and 350 KEGG signalling pathways from T. rubripes and D. labrax, respectively. Immune-related categories included Toll-like receptors, MAPK, lysosome, C-type lectin receptor and NOD-like receptor signalling pathways were significantly enriched pathways. In immune-related signalling pathways, we found that AP-1, P38, IL-1β, HSP90 and PLA were significantly up-regulated DEGs in T. rubripes, but P38 and PLA were significantly down-regulated in D. labrax. In this study, transcriptome was used to analyse the difference between scaly and non-scaly fish infection by C. irritans, which not only provided a theoretical basis for the infection mechanism of C. irritans, but also laid a foundation for effectively inhibiting the occurrence of this disease. Our work provides further insight into the immune response of host resistance to C. irritans.

Bioprinting stem cells: building physiological tissues one cell at a time

Bioprinting aims to direct the spatial arrangement in three dimensions of cells, biomaterials, and growth factors. The biofabrication of clinically relevant constructs for the repair or modeling of either diseased or damaged tissues is rapidly advancing, resulting in the ability to three-dimensional (3D) print biomimetic platforms which imitate a large number of tissues in the human body. Primary tissue-specific cells are typically isolated from patients and used for the fabrication of 3D models for drug screening or tissue repair purposes. However, the lack of resilience of these platforms, due to the difficulties in harnessing, processing, and implanting patient-specific cells can limit regeneration ability. The printing of stem cells obviates these hurdles, producing functional in vitro models or implantable constructs. Advancements in biomaterial science are helping the development of inks suitable for the encapsulation and the printing of stem cells, promoting their functional growth and differentiation. This review specifically aims to investigate the most recent studies exploring innovative and functional approaches for the printing of 3D constructs to model disease or repair damaged tissues. Key concepts in tissue physiology are highlighted, reporting stem cell applications in biofabrication. Bioprinting technologies and biomaterial inks are listed and analyzed, including recent advancements in biomaterial design for bioprinting applications, commenting on the influence of biomaterial inks on the encapsulated stem cells. Ultimately, most recent successful efforts and clinical potentials for the manufacturing of functional physiological tissue substitutes are reported here, with a major focus on specific tissues, such as vasculature, heart, lung and airways, liver, bone and muscle.

The pertussis hypothesis: Bordetella pertussis colonization in the etiology of asthma and diseases of allergic sensitization

Decades of peer reviewed evidence demonstrate that: 1)Bordetellapertussisand pertussis toxin are potent adjuvants, inducing asthma and allergic sensitization in animal models of human disease, 2)Bordetella pertussisoften colonizes the human nasopharynx, and is well documented in highly pertussis-vaccinated populations and 3) in children, a history of whooping cough increases the risk of asthma and allergic sensitization disease. We build on these observations with six case studies and offer a pertussis-based explanation for the rapid rise in allergic disease in former East Germany following the fall of the Berlin Wall; the current asthma, peanut allergy, and anaphylaxis epidemics in the United States; the correlation between the risk of asthma and gross national income per capita by country; the lower risk of asthma and allergy in children raised on farms; and the reduced risk of atopy with increased family size and later sibling birth order. To organize the evidence for the pertussis hypothesis, we apply the Bradford Hill criteria to the association between Bordetella pertussisand asthma and allergicsensitization disease. We propose that, contrary to conventional wisdom that nasopharyngealBordetella pertussiscolonizing infections are harmless, subclinicalBordetella pertussiscolonization is an important cause of asthma and diseases of allergic sensitization.

The combined effect of ambient ozone exposure and toxic air releases on hospitalization for asthma among children in Harris County, Texas

This study represents an analysis of the effect of exposure to ambient ozone and toxic air releases on hospitalization for asthma among children in Harris County, Texas. Our study identified temporal and spatial variations in asthma hospitalization across the study region and explored the combined effect of exposure to ambient ozone and air toxics on asthma hospitalization. Asthma hospitalization hot spots and clusters were mostly not located on zip codes with reported high quantities of total air releases of chemical pollutants. There was no significant interaction between ambient ozone exposure and toxic air releases relative to asthma hospitalization. The major predictor of asthma hospitalization was season, with hospitalization rate per 10,000 people for asthma being highest in winter period when ozone levels are usually lowest.

Developing a tissue-engineered model of the human bronchiole

Scientists are always looking for new tools to better mimic human anatomy and physiology, especially to study chronic respiratory disease. Airway remodelling is a predominant feature in asthma and occurs in conjunction with chronic airway inflammation. Both the inflammatory and repair processes alter the airway wall which is marked by anatomical, physiological and functional changes. A tissue-engineered model of bronchiole remodelling presents a novel approach to investigating the initiation and progression of airway remodelling. By developing a unique bioreactor system, cylindrical-shaped bronchioles constructed from well-characterized human lung primary cells have been engineered and examined with a much greater control over experimental variables. We have grown human bronchioles composed of fibroblasts, airway smooth muscle cells, small airway epithelial cells and extracellular matrices. The various cell types are in close proximity to one another for cell-cell signalling and matrix interactions. The cylindrical geometry of the tissue applies radial distension for mechanotransduction and the air interface provides a natural environment for the epithelial cells. Optimal cell density, extracellular matrix concentration and media composition were determined. Immunohistochemistry verified bronchiole phenotypic stability. Quiescence was gauged by protein expression which verified a change in phenotype after the initial fabrication stage and implementation of the air interface. A fabrication timeline was devised for repeatable bronchiole fabrication and to understand tissue contraction and cell-seeding duration. The stability of the bronchiole structures and their cellular composition lends these bronchioles to study cell-cell interactions and remodelling events while maintaining in vivo geometrical dimensions and relationships.

Teachable moments: improving pediatric asthma outcomes through physician education

In light of concerns about adherence to the 1997 National Heart Lung and Blood Institute guidelines as well as the 2002 update regarding treatment of asthma, the authors evaluate educational interventions designed to have a positive impact on pediatric patient outcomes. Social cognitive theory can provide the foundation of interventions for physicians that are intended to promote self efficacy in treating asthma patients. Emphasizing the need for physician education based on principles of adult learning, the authors call for more research in this area and encourage the incorporation of distance learning techniques into educational endeavors. The purpose of this article is to review research on the impact of healthcare provider education designed to increase use of practice guidelines on the quality of pediatric asthma care as reflected in patient outcomes and, ultimately, in cost of treatment.

Expression of the Th1-specific cell-surface protein Tim-3 increases in a murine model of atopic asthma

T-cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3) is preferentially expressed on Th1-helper type T-cells and functions to repress the Th1-mediated immune response. However, the role of Tim-3 during the inflammatory pathogenesis of asthma remains unclear. This study determines the expression level of Tim-3 in CD4+ T-cells within the peripheral blood and bronchoalveolar lavage fluid (BALF) isolated from a murine model of atopic asthma and explores the potential role of Tim-3 during the inflammatory response. Mice were randomly divided into normal control, asthma day 1, and asthma day 7 groups, and peripheral blood T lymphocytes and BALF cells were collected. The ratio of Tim-3+/CD4+ cells among the total CD4+cell populations from peripheral blood and BALF was determined by flow cytometry, and the expression of the Tim-3 mRNA was determined by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). In contrast with the normal control group, the ratio of Tim-3+/CD4+:CD4+ cells and the level of Tim-3 mRNA in both the peripheral blood T lymphocytes and BALF cells among the asthma day 1 and asthma day 7 groups were significantly increased (p < 0.01), and those in the asthma day 7 group were higher than the asthma day 1 group (p < 0.05). There was also a positive correlation between the ratio of Tim-3+/CD4+:CD4+ detected in BALF and that the ratio detected in peripheral blood T lymphocytes (r = 0.84, p < 0.01). Therefore, the expression of Tim-3 is increased in CD4+ T-cells following airway challenge and likely affects asthma-induced inflammation by repressing the Th1-mediated immune response.

Dual inhibition of cathepsin G and chymase is effective in animal models of pulmonary inflammation

RATIONALE

Mast cells and neutrophils are key contributors to the pathophysiological inflammatory processes that underpin asthma and chronic obstructive pulmonary disease, partly through the release of noxious serine proteases, including cathepsin G (Cat G) and chymase. From this standpoint, a dual inhibitor of neutrophil Cat G and mast cell chymase could protect against these disease-related inflammatory responses.

OBJECTIVES

We examined the antiinflammatory pharmacology of RWJ-355871, a dual inhibitor of Cat G and chymase, in animal models of inflammation that evince pathophysiological pathways relevant to asthma and chronic obstructive pulmonary disease to determine the therapeutic potential of this compound.

METHODS

In an ovalbumin (OVA)-sensitized rat model, RWJ-355871 was administered to block the mast-cell-mediated increase in paw volume caused by OVA injection. In a sheep asthma model, antigen-induced airway responses were assessed with and without aerosol treatment with RWJ-355871. In a murine tobacco-smoke model of airway inflammation, the effect of RWJ-355871 on smoke-induced neutrophilia was determined.

MEASUREMENTS AND MAIN RESULTS

Intravenous treatment of OVA-sensitized rats with RWJ-355871 provided dose-dependent reduction in the increase in rat paw volume. In allergic sheep, aerosol pretreatment with RWJ-355871 showed dose-dependent inhibition of the antigen-induced early response, late response, and post-antigen-induced airway hyperreponsiveness. In tobacco-smoke-exposed mice, nebulized RWJ-355871 significantly reduced the smoke-induced neutrophilia from the levels observed in untreated mice.

CONCLUSIONS

The preclinical antiinflammatory effects of RWJ-355871 in these animal models of inflammation indicate that this dual inhibitor may have therapeutic utility for treating airway inflammatory diseases involving mechanisms that depend on Cat G and/or chymase.

Assessing the association between environmental impacts and health outcomes: a case study from Florida

The Centers for Disease Control and Prevention (CDC) created the Environmental Public Health Tracking (EPHT) program to integrate hazard monitoring, exposure, and health effects surveillance into a cohesive tracking network. Part of Florida's effort to move toward implementation of EPHT is to develop models of the spatial and temporal association between myocardial infarctions (MIs) and ambient ozone levels in Florida. Existing data were obtained from Florida's Agency for Health Care Administration, Florida's Department of Environmental Protection, the U.S. Census Bureau, and CDC's Behavioral Risk Factor Surveillance System. These data were linked by both ignoring spatial support and using block kriging, a support-adjusted approach. The MI data were indirectly standardized by age, race/ethnicity, and sex. The state of Florida was used as the comparison standard to compute the MI standardized event ratio (SER) for each county and each month. After the data were linked, global models were used initially to relate MIs to ambient ozone levels, adjusting for covariates. The global models provide an estimated relative MI SER for the state. Realizing that the association in MIs and ozone might change across locations, local models were used to estimate the relative MI SER for each county, again adjusting for covariates. Results differed, depending on whether the spatial support was ignored or accounted for in the models. The opportunities and challenges associated with EPHT analyses are discussed and future directions highlighted.

Infant frequent wheezing correlated to Clara cell protein 10 (CC10) polymorphism and concentration, but not allergy sensitization, in a perinatal cohort study

BACKGROUND

Wheezing episodes are common in young infants. However, the molecular mechanism of wheezing is unclear, and very few therapeutic regimens are effective.

OBJECTIVE

This study investigated the genetic and environmental factors predisposing to infant wheezing in a birth cohort study.

METHODS

A cohort of 1211 pregnant women was recruited for this study. Infant wheezing episodes during the first 18 months of life were correlated to parental atopic history, parental smoking, prematurity, CB IgE levels, and the sequence variant (G+38A) of the Clara cell protein 10 (CC10) gene encoding a secretary anti-inflammatory CC10 protein.

RESULTS

Nine hundred eighty-three infants completed umbilical cord blood collection, and 813 infants completed the 18-month postnatal follow-up. Twenty-two percent of the infants experienced at least 1 wheezing episode, and 6.6% of the infants experienced frequent wheezing (> or =3 episodes). Multivariate logistic regression showed that male sex and the CC10 G+38A polymorphism, but not prematurity, CB IgE level, passive smoking, or parental atopy, were predictors of frequent wheezing. Further studies found that infant frequent wheezing was significantly associated with the CC10 +38AA genotype and lower plasma CC10 levels at 18 months of age (P = .046), and infants with acute wheezing episodes had significantly lower CC10 levels than those without (P = .023). No association of wheezing episodes with allergic sensitization was observed in this cohort population.

CONCLUSION

Infant frequent wheezing is associated with the CC10 G+38A polymorphism and lower CC10 levels but not infant atopy.

CLINICAL IMPLICATIONS

Lower CC10 expression, but not allergy sensitization, is involved in the pathogenesis of infant frequent wheezing.

Investigation of a potential food effect on the pharmacokinetics of roflumilast, an oral, once-daily phosphodiesterase 4 inhibitor, in healthy subjects

This open, randomized, single-dose crossover study investigated effects of a high-fat meal on the pharmacokinetics of roflumilast and its major active N-oxide metabolite. Twelve healthy subjects received oral roflumilast 500 microg (2 x 250 microg) after overnight fasting and after breakfast. Blood was sampled up to 54 hours for pharmacokinetic profiling of roflumilast and N-oxide. Geometric mean ratios (fed/fasted) for point estimates (PE) and 90% confidence intervals (CI) were calculated for AUC(0-last), AUC(0-infinity), and C(max) of both compounds. After the meal, roflumilast C(max) (PE, 0.59; 90% CI, 0.49-0.70) was modestly reduced; N-oxide C(max) (PE, 0.95; 90% CI, 0.90-1.01) was unchanged. Roflumilast t(max) was delayed in fed state (2.0 +/- 0.4 hours) versus fasted state (1.0 +/- 0.2 hours); N-oxide t(max) was unaltered. No significant food effect on roflumilast AUC(0-last) (PE, 1.04; 90% CI, 0.90-1.21), AUC(0-infinity) (PE, 1.12; 90% CI, 1.00-1.25), and respective N-oxide AUCs (PE, 0.91; 90% CI, 0.79-1.04; PE, 0.99; 90% CI, 0.92-1.06) occurred. Because roflumilast N-oxide is the major contributor to roflumilast's overall pharmacologic effects, these findings suggest that roflumilast can be taken with or without food.

Adverse maternal outcomes in women with asthma: differences by race

PURPOSE

To examine the relationship between race and adverse maternal outcomes in women with asthma.

STUDY DESIGN AND METHODS

This retrospective cohort study examined 11 adverse maternal outcomes across racial groups of 13,900 pregnant women with asthma (age 13 to > or = 40) who gave birth between 1998 and 1999. The data were abstracted from a national database, The National Inpatient Sample (NIS), available through Health Care and Utilization Project (HCUP) maintained and disseminated by the Agency for Healthcare Research and Quality (AHRQ). Maternal age and comorbidities were adjusted in multivariate analysis.

RESULTS

For women with asthma, African Americans were more likely than Whites to have preterm labor and infection of the amniotic cavity; Hispanic women had comparable outcomes with the exception that postdate pregnancy was less likely to be 42 weeks; and Asian/Pacific Islander women had a higher risk of having gestational diabetes and infection of the amniotic cavity.

CLINICAL IMPLICATIONS

As adverse maternal outcomes for women with asthma were higher in minorities, and as minorities have traditionally had more barriers to healthcare, the study results indicate that more effort needs to be made to educate nurses, consumers, and government officials about the potential adverse maternal outcomes of asthma during pregnancy. Public awareness may assist in overcoming the barriers to healthcare experienced by minorities.

Sideline management of asthma

The timely, efficient, and effective sideline management of asthma must be grounded on an understanding of the disease processes, awareness of evidence-based therapeutic intervention, and thorough knowledge of the individual athlete's medical history and current physical condition. There is accumulating evidence that exercise-induced airway narrowing, if unrecognized or inadequately treated, can progress to a severe life-threatening status and should always be viewed as a potential medical emergency. A widening range of therapeutic measures is currently available to prevent and to treat exercise asthma, and treatment must be tailored to the individual circumstances to optimize response.

Sideline management of asthma

The timely, efficient, and effective sideline management of asthma must be based on an understanding of the disease processes, awareness of evidence-based therapeutic intervention, and thorough knowledge of the individual athlete's past and present medical history. There is accumulating evidence that exercise-induced airway narrowing, if unrecognized or inadequately treated, can progress to a severe life-threatening status and should always be viewed as a potential medical emergency. A widening range of therapeutic measures is currently available to prevent and treat exercise asthma, and treatment must be tailored to the individual circumstances in order to optimize response.

Measuring asthma quality in primary care: can we develop better measures?

OBJECTIVE

Asthma is common and commonly under-treated. Currently quality indicators often do not provide specific directions for areas of improvement. This work lays the foundation for a quality improvement initiative that provides practice-specific feedback related directly to clinical activities completed for individual patients with asthma.

METHODS

Medical record review using a group of quality assessment elements developed from previous medical record review studies of asthma care and the NAEPP asthma care guidelines.

RESULTS

For 500 school children ages 5-18 yr who made one or more asthma visits in the year of interest, the frequency of daytime asthma symptoms were recorded in 54% of patients' medical records at any time during a one-year period, while nighttime symptom frequency was recorded in 33%. Only 12% of medical records recorded any information on missed work, school or activity days. Nine percent recorded information or acknowledged any asthma "triggers". Asthma severity level was documented in only an additional 4% of the children's records. Most medical records documented prescribed asthma medications and dosages (85%) but few recorded the medications or dosages the patients were actually taking.

CONCLUSIONS

Many medical records do not include the basic clinical information required to assess asthma severity, adherence to asthma therapy or the response to therapy. This lack of information makes implementation of asthma care guidelines impossible. Therefore, these measures may be useful baseline quality indicators to begin the process of improving asthma care.

Effects of adenoviral gene transfer of mutated IkappaBalpha, a novel inhibitor of NF-kappaB, on human monocyte-derived dendritic cells

AIM

To investigate the effects of adenoviral gene transfer of IkappaBalpha mutant (IkappaBalphaM), a novel inhibitor of nuclear factor kappaB (NF-kappaB), on apoptosis, phenotype and function of human monocyte-derived dendritic cells (DC).

METHODS

Monocytes, cocultured with granulocyte/macrophage colony-stimulating factor (GM-CSF; 900 ng/mL) and interleukin (IL)-4 (300 ng/mL) for 5 d, followed by stimulation with lipopolysaccharide (LPS; 100 ng/mL) for 2 d differentiated into mature DC. Monocytes were either left untransfected or were transfected with AdIkappaBalphaM or AdLacZ. The transcription and expression of the IkappaBalphaM gene, and the inhibitory effect of IkappaBalphaM on tumor necrosis factor (TNF)-alpha-induced NF-kappaB activation in mature DC were detected by polymerase chain reaction (PCR), reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis, and electrophoretic mobility shift assays, respectively. The phenotype, apoptosis, IL-12 secretion level of DC, and ability to stimulate the proliferation of T cells were determined by flow cytometry, enzyme-linked immunosorbent assay and mixed leukocyte reaction.

RESULTS

PCR and RT-PCR were used to detect a unique 801 bp band in AdIkappaBalphaM-transfected mature DC, and also a dose- and time-dependent expression of the IkappaBalphaM gene, which peaked at a multiplicity of infection of 100 pfu/cell and at 48 h. Furthermore, AdIkappaBalphaM significantly suppressed the TNF-alpha-induced NF-kappaB activation, augmented apoptosis, downregulated CD80, CD83, and CD86 surface molecules, IL-12 secretion levels and the ability to stimulate the proliferation of T cells in mature DC.

CONCLUSION

AdIkappaBalphaM effectively transfected and potently inhibited NF-kappaB activation in monocyte-derived mature DC. Overexpression of the IkappaBalphaM gene in mature DC may contribute to T-cell immunosuppression through induction of DC apoptosis and downregulation of B7 molecules, providing a potential strategy for future DC-based immunotherapy of asthma.

Return to play following exercise-induced bronchoconstriction

OBJECTIVE

To review evidence-based support for return to play criteria following acute exercise-induced bronchoconstriction.

DATA SOURCES

Electronic databases Ovid Medline and PubMed were searched for papers relating to exercise related asthma and bronchoconstriction and return to play criteria. Additional references from the bibliographies of retrieved articles were also reviewed.

DATA SYNTHESIS

There is clear evidence that exercise-induced airways narrowing is increasing in prevalence among athletes from school children to Olympians to professionals, yet there have been no studies specifically addressing return to play criteria. Although deaths from exercise associated bronchoconstriction were previously thought to be rare, recent reports of such deaths call for increased awareness by physicians, athletic trainers, and coaches of the potential fatal consequences of unrecognized episodes or of inadequate treatment.

CONCLUSIONS

No agreed-upon protocol for safe return to play following an acute episode of exercise induced bronchoconstriction has been published. A specific detailed protocol for return to play would assist physicians and other heath professionals to determine with greater confidence that an athlete is fully recovered and can safely return to play.

Changing impact of gastroesophageal reflux in medical and otolaryngology practice

OBJECTIVES/HYPOTHESIS

A major trend in gastroesophageal reflux disease (GERD) is an observed increased prevalence of the problem, with an associated burden on health care resources. There are relatively few objective reports of increasing prevalence of this disease, and there are no epidemiologic reports that discuss changing practice strategies in managing the disease. The clinical problem is of critical importance to practicing otolaryngologists, who manage the impact of GERD on diseases affecting the ear, nose, and throat. The hypothesis of this thesis is that 1) GERD is an increasing problem affecting outpatient office visits over time, and 2) the disease is increasingly managed with prescription pharmacotherapy.

STUDY DESIGN

Retrospective national medical database review using the National Ambulatory Medical Care Survey.

METHODS

Twelve years of data (1990-2001) were examined with visits weighted to provide U.S. estimates of care. Average annual frequencies and visit rates were calculated for total visits and by age, sex, race, and physician specialty. Selected issues in GERD treatment were also examined, including prescriptions and physician/patient counseling regarding stress management, tobacco abuse, and diet modification. Trends were reported based on changes in care across three time periods to satisfy statistical significance: 1990 to 1993, 1994 to 1997, and 1998 to 2001.

RESULTS

Between 1990 and 1993 and 1998 and 2001, there was a significant increase in U.S. ambulatory care visits for GERD, from a rate of 1.7 per 100 to 4.7 per 100. There were no significant changes in race, although there was a small trend toward increased GERD visits in the age group over 44 years old and in the male sex. Office visits to otolaryngologists increased from 89,000 to 421,000 between the time periods of 1990 to 1993 and 1998 to 2001. This also represented a percent increase in office encounters by otolaryngologists compared with visits by all specialties from 2.9% to 4.4%. Over the three time periods, there was a fall in prescriptions for histamine (H2) blockers from 58.1% to 20.7% of total prescriptions. Over the same three time periods, prescriptions of proton pump inhibitors increased from 13.2% to 64.6%. Physician recommendations for over the counter medications fell from 18.8% to 6.6%. Average annual counseling during ambulatory care visits for GERD was assessed for the period from 1998 to 2001 as follows: diet counseling was provided at 27.2% of encounters, tobacco cessation counseling was provided at 3.9%, and stress management was discussed at 3.9%.

CONCLUSIONS

During the 1990s, there was a substantial increase in the use of ambulatory care services for GERD. Although much of this increase was among the primary care community, otolaryngologists appeared to have an increasingly prominent role in the management of this disease. There have also been dramatic changes in physician prescribing patterns for GERD, with the emergence of the predominant role of proton pump inhibitors. However, the use of physician counseling for lifestyle modification of factors known to affect GERD remains very low. The increasing impact of GERD on physician practice emphasizes the importance of both physician and patient education in the delivery of health care related to this disease.

Using the ecology model to describe the impact of asthma on patterns of health care

BACKGROUND

Asthma changes both the volume and patterns of healthcare of affected people. Most studies of asthma health care utilization have been done in selected insured populations or in a single site such as the emergency department. Asthma is an ambulatory sensitive care condition making it important to understand the relationship between care in all sites across the health service spectrum. Asthma is also more common in people with fewer economic resources making it important to include people across all types of insurance and no insurance categories. The ecology of medical care model may provide a useful framework to describe the use of health services in people with asthma compared to those without asthma and identify subgroups with apparent gaps in care.

METHODS

This is a case-control study using the 1999 U.S. Medical Expenditure Panel Survey. Cases are school-aged children (6 to 17 years) and young adults (18 to 44 years) with self-reported asthma. Controls are from the same age groups who have no self-reported asthma. Descriptive analyses and risk ratios are placed within the ecology of medical care model and used to describe and compare the healthcare contact of cases and controls across multiple settings.

RESULTS

In 1999, the presence of asthma significantly increased the likelihood of an ambulatory care visit by 20 to 30% and more than doubled the likelihood of making one or more visits to the emergency department (ED). Yet, 18.8% of children and 14.5% of adults with asthma (over a million Americans) had no ambulatory care visits for asthma. About one in 20 to 35 people with asthma (5.2% of children and 3.6% of adults) were seen in the ED or hospital but had no prior or follow-up ambulatory care visits. These Americans were more likely to be uninsured, have no usual source of care and live in metropolitan areas.

CONCLUSION

The ecology model confirmed that having asthma changes the likelihood and pattern of care for Americans. More importantly, the ecology model identified a subgroup with asthma who sought only emergent or hospital services.

Research on environmental health interventions: ethical problems and solutions

This article reviews a variety of ethical issues one must consider when conducting research on environmental health interventions on human subjects. The paper uses the Kennedy Krieger Institute lead abatement study as well as a hypothetical asthma study to discuss questions concerning benefits and risks, risk minimization, safety monitoring, the duty to warn, the duty to report, the use of control groups, informed consent, equitable subject selection, privacy, conflicts of interest, and community consultation. Research on environmental health interventions can make an important contribution to our understanding of human health and disease prevention, provided it is conducted in a manner that meets prevailing scientific, ethical, and legal standards for research on human subjects.

Asthma severity: the patient's perspective

BACKGROUND

Although asthma is a common condition, limited epidemiological data exists on the distribution or course of asthma severity. We know even less about how patients or parents rate the severity of their or their child's asthma or what factors they associate with more severe asthma. A large nationally diverse sample of asthma patients' self-assessment of severity is available but has not been analyzed to look at asthma severity from the patients' perspective.

METHOD

Data from the "household" and "event" files from the 1999 Medical Expenditure Panel Survey were combined to obtain a distribution of patient-reported asthma severity and the health care utilization, medication usage, and personal characteristics associated with different levels of self-reported severity for that subgroup that answered the chronic disease portion of the survey.

RESULTS

Almost two thirds of patients (63% of adults) or parents (65% of children) described their or their child's asthma as very or somewhat serious. Among both children and adults, more severe asthma was associated with greater numbers of missed school and workdays, and lower overall health status. The associated differences in health utilization varied by age. Models of severity based on available NAEPP criteria explained less than 10% of the participant's variation in self-reported asthma severity.

CONCLUSION

Parents and patients with asthma appear to use different metrics than physicians and researchers to define the more severe categories of asthma. This disparity suggests the need for an asthma measure that is more widely understood, and accepted by patients and clinicians to serve as a tool to improve asthma-related communications and the achievement of mutually determined therapy goals.

Outcome results of a school-based screening program for undertreated asthma

BACKGROUND

Undertreatment of asthma is associated with significant potentially preventable morbidity, including frequent school absences. Guideline dissemination and clinician education have met with variable success. School-based identification of children with potentially undertreated asthma may provide an alternative strategy for improving asthma management in children.

OBJECTIVE

To evaluate the effectiveness of school-based identification of potentially undertreated asthma.

METHODS

A controlled trial of school-based identification of children with known but symptomatic asthma using mailed parent surveys, letters recommending medical follow-up, and medical record review to evaluate changes in asthma treatment after referral.

RESULTS

Most parents (79.9%, n = 5,116 respondents) responded to the survey and 19.4% (n = 994) of children were reported to have a physician diagnosis of asthma or reactive airway disease. Letters of referral were sent to 489 children with parent-reported asthma who were identified as having potentially undertreated asthma. Approximately one-third (31.2%, n = 153) of these children had physician visits, and 92 (18.8% of all referred) had documented medication changes. In addition, there were 20 new physician diagnoses in this group of children. In the control group of 604 children with asthma, there were significantly fewer children with asthma-related visits (131, 21.7%, P = 0.0004) and children with medication changes (74, 12.3%, P = 0.002) in a comparable 6-month window.

CONCLUSIONS

School-based screening or case identification increased the number of physician asthma-related visits and changes in asthma therapy.

Extended freeze-dried Mycobacterium bovis Bacillus Calmette-Guérin induces the release of interleukin-12 but not tumour necrosis factor-alpha by alveolar macrophages, both in vitro and in vivo

BACKGROUND

Airway hyper-responsiveness (AHR), chronic airway inflammation and predominance of the T helper type-2 (Th2; IL-4, IL-5, IL-13) over the Th1 (IL-2, IFN-gamma) immune response are hallmarks of asthma. Alveolar macrophages (AM) are the most numerous cells in the airway lumen, where they represent the first immune cell population encountered by inhaled antigens. AM act as antigen-presenting cells (APC) and they release various soluble mediators and enzymes. AM thus play a prominent role in the modulation of the local immunity in airways. In allergic airways, AM have been implicated in the pathogenesis of inflammation by promoting the Th2 versus the Th1 cytokine patterns.

OBJECTIVES

Infections with attenuated bacteria or challenges with bacterial products may involve AM. Such stimuli have been shown to potentially restore the Th1/Th2 balance in asthmatic airways, but they also induce the release of inflammatory mediators. We investigated the response of AM when stimulated by two preparations of non-proliferating Bacillus Calmette-Guérin (BCG).

METHODS

We evaluated the cytokine production by AM from BP2 and C57BL/6 mice when cultured with heat-killed (HK) and extended freeze-dried (EFD) BCG. We then investigated in vivo the release of soluble factors in the airway lumen of mice after instillation of these BCG preparations. Finally, we studied the profile of cytokine transcripts in the lung of mice pre-treated with BCG and then challenged with ovalbumin (OVA).

RESULTS

HK BCG induced the production of both TNF-alpha and IL-12, and did not prevent high levels of Th2 cytokine transcripts. In contrast, EFD BCG induced a response dominated by the production of IL-12, with no later over-expression of Th2 cytokine transcripts.

CONCLUSION

Our results show that EFD BCG induce the release of the Th1-promoting cytokine IL-12 by AM, without the deleterious effects of HK BCG. These data suggest that EFD BCG may be considered as a potential novel treatment to restore the Th1/Th2 imbalance in asthma.

Therapeutic efficacy of an E coli strain carrying an ovalbumin allergenic peptide as a fused protein to OMPC in a murine model of allergic airway inflammation

An Escherichia coli strain expressing the ovalbumin (OVA) 323-329 allergenic peptide on the bacterial surface was evaluated for its ability to reduce the lung inflammatory response in mice allergic to OVA. BALB/c mice were rendered allergic by means of two intraperitoneal injections of OVA suspended in alum 5 days apart, and one intratracheal boost 1 week later. The mice were then treated with two intranasal, 1 week apart, doses of 4x10(9) E. coli-UH302 transformed with plasmids pST13 or pST13-OVA(323-339), which bear the OmpC porin from Salmonella enterica serovar Typhi or the OmpC with the OVA allergenic 323-339 amino acid sequence inserted in the external loop 5. The allergic inflammatory reaction was evaluated on day 31, finding that mice treated with E. coli-UH302-pST13-OVA reduced four to seven times perivascular and peribronchial infiltrates, mucus production, goblet cell hyperplasia and eosinophils when compared with mice treated with E. coli-UH302-pST13 or saline solution. These results were consistent with a significant decrease of IL-5 mRNA and induction of IFN-gamma mRNA in cells from bronchio-alveolar lavages (BAL). Specific serum IgE anti-OVA was also reduced, although the decrease did not reach statistical significance. These results demonstrate that the bacterial live vector bearing an allergenic peptide successfully moderated two important components of allergy, pulmonary inflammation and mucus overproduction.

Is there scientific evidence that suppression of acute diseases in childhood induce chronic diseases in the future?

Seeking to understand the individual in his symptomatic totality has been an aim of homeopathy since its beginning. Throughout its history, homeopaths have been concerned that inadequate treatment of acute diseases in childhood may lead to future chronic diseases. Hahnemann cautioned that by treating acute diseases with allopathic medicine, with strong doses of drugs, or suppressing local symptoms of those diseases, would increase the risk of future chronic diseases. Burnett proposed the theory of vaccinosis and warned of chronic manifestations subsequent to smallpox vaccination. French homeopaths, seeking the physiopathological origin of chronic diseases, correlated it to the abnormal reaction of the reticuloendothelial system (RES). Through the study of experimental pathology, Maffei attributed symptomatic manifestations to the imbalance between the immunological phenomena of allergy and immunity. He termed the sensitizing and pathogenic effects of medications and vaccines, 'metallergy' and 'parallergy', respectively. The hygiene hypothesis is based on evidence that the imbalance of immunological response in childhood, specifically among the Th1 and Th2 lymphocyte subpopulations, is responsible for the development of some allergic and chronic diseases in the future. The deranging factor for the predisposition to future allergic response (Th2) is the obstruction of natural manifestations of infectious diseases (Th1 response) in young children. Homeopathic treatment aims to equilibrate vital reaction, corresponding to an integrative physiological response, it may regulate Th1/Th2 imbalance. However, clinical trials to support this hypothesis are lacking.