Severe hypercalcemia and a pelvic brown tumor in an adolescent with primary hyperparathyroidism: a case report.

BACKGROUND: Primary hyperparathyroidism may present in a myriad of manners, varying from an incidental asymptomatic biochemical finding to gastrointestinal, psychiatric, renal, and bone manifestations. While hyperparathyroidism remains a rare diagnosis in the pediatric population, the initial approach to diagnosis and management of hypercalcemia in children is imperative for the general pediatrician. Herein, we describe an adolescent who presented with a lytic bone lesion and severe, symptomatic hypercalcemia due to primary hyperparathyroidism. CASE PRESENTATION: A 14-year-old male presented with vomiting, constipation, abdominal pain, and lethargy. He had an elevated total corrected calcium of 4.3 mmol/L. He was found to have a large pelvic lytic tumor consistent with a brown tumor due to primary hyperparathyroidism. He received pharmacologic therapy for stabilization of his hypercalcemia, including intravenous saline, intravenous bisphosphonates, and calcitonin. He subsequently received definitive therapy via parathyroidectomy and his post-operative course was complicated by hungry bone syndrome. Long-term follow-up has found full resolution of the lytic lesion and restored calcium homeostasis. CONCLUSIONS: We present this case to highlight the possible presentations of hypercalcemia and hyperparathyroidism that are essential for a general pediatrician to recognize to ensure prompt diagnosis and management. Evaluation for hypercalcemia should be considered in patients with suggestive symptoms and physical exam findings. To our knowledge, this patient represents the first reported pediatric case of a pelvic brown tumor in an adolescent. While the multi-systemic complications of hyperparathyroidism may be quite severe, swift and appropriate management may mitigate these clinical outcomes.

A pathogenic role for tumor necrosis factor-related apoptosis-inducing ligand in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a life-threatening inflammatory respiratory disorder, often induced by cigarette smoke (CS) exposure. The development of effective therapies is impaired by a lack of understanding of the underlining mechanisms. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a cytokine with inflammatory and apoptotic properties. We interrogated a mouse model of CS-induced experimental COPD and human tissues to identify a novel role for TRAIL in COPD pathogenesis. CS exposure of wild-type mice increased TRAIL and its receptor messenger RNA (mRNA) expression and protein levels, as well as the number of TRAIL(+)CD11b(+) monocytes in the lung. TRAIL and its receptor mRNA were also increased in human COPD. CS-exposed TRAIL-deficient mice had decreased pulmonary inflammation, pro-inflammatory mediators, emphysema-like alveolar enlargement, and improved lung function. TRAIL-deficient mice also developed spontaneous small airway changes with increased epithelial cell thickness and collagen deposition, independent of CS exposure. Importantly, therapeutic neutralization of TRAIL, after the establishment of early-stage experimental COPD, reduced pulmonary inflammation, emphysema-like alveolar enlargement, and small airway changes. These data provide further evidence for TRAIL being a pivotal inflammatory factor in respiratory diseases, and the first preclinical evidence to suggest that therapeutic agents that target TRAIL may be effective in COPD therapy.

T regulatory cell phenotypes in peripheral blood and bronchoalveolar lavage from non-asthmatic and asthmatic subjects.

BACKGROUND: An unresolved issue in T regulatory cells' cell biology is the lack of consensus on phenotypic markers that accurately define the natural Treg (nTreg) population. OBJECTIVES: To examine nTreg frequency and functional capacity in healthy controls and their frequency in asthmatic subjects using three different phenotypic strategies. We hypothesized that phenotypically different nTreg are quantitatively and functionally different. METHODS: Thirty-four healthy, non-asthmatic and 17 asthmatic subjects were studied. Three nTreg phenotypes were defined as follows: nTreg1 (CD4(+) CD25(+) Foxp3(+) ), nTreg2 (CD4(+) CD25(+) CD127(low) Foxp3(+) ), and nTreg3 (CD4(+) CD25(high) Foxp3(+) ). The flow cytometric determination of nTreg frequency in peripheral blood (PB) and bronchoalveolar lavage (BAL) was performed using fluorescently labelled antibodies. Peripheral blood nTreg functional capacity was assessed using a CFSE-based suppression assay. RESULTS: There was a significantly lower frequency of PB nTreg3 compared to nTreg2 and nTreg1 (P < 0.05). Both nTreg2 and nTreg3 had a significantly greater suppressive capacity than nTreg1 at T responder (Tresp) to nTreg ratios of 16 : 1 up to 1 : 1 (P < 0.01). Asthmatics exhibited a significantly lower PB nTreg3 and nTreg1 frequency than healthy controls (P < 0.05). There were no differences between healthy controls and asthmatic subjects when comparing BAL nTreg frequency. CONCLUSIONS AND CLINICAL RELEVANCE: Phenotypically different nTreg subsets are quantitatively and functionally different and are variably observed in asthma. The CD4(+) CD25(high) Foxp3(+) phenotype was the least frequent, but demonstrated the greatest suppression, and was significantly lower in PB of asthmatic subjects. Consequently, it is imperative that nTreg phenotypes be clearly defined and that the interpretation of their frequency and function be phenotype specific.

Amelioration of ovalbumin-induced allergic airway disease following Der p 1 peptide immunotherapy is not associated with induction of IL-35.

In the present study, we show therapeutic amelioration of established ovalbumin (OVA)-induced allergic airway disease following house dust mite (HDM) peptide therapy. Mice were sensitized and challenged with OVA and HDM protein extract (Dermatophagoides species) to induce dual allergen sensitization and allergic airway disease. Treatment of allergic mice with peptides derived from the major allergen Der p 1 suppressed OVA-induced airway hyperresponsiveness, tissue eosinophilia, and goblet cell hyperplasia upon rechallenge with allergen. Peptide treatment also suppressed OVA-specific T-cell proliferation. Resolution of airway pathophysiology was associated with a reduction in recruitment, proliferation, and effector function of T(H)2 cells and decreased interleukin (IL)-17⁺ T cells. Furthermore, peptide immunotherapy induced the regulatory cytokine IL-10 and increased the proportion of Fox p3⁺ cells among those expressing IL-10. Tolerance to OVA was not associated with increased IL-35. In conclusion, our results provide in vivo evidence for the creation of a tolerogenic environment following HDM peptide immunotherapy, leading to the therapeutic amelioration of established OVA-induced allergic airway disease.

Appropriateness of in vitro potency tests as a measure of vaccine or reference stability.

A proposed definition of a stability indicating assay is "a validated quantitative analytical procedure that can detect changes over time in the pertinent properties of the product" (Federal Register/Vol. 75 No. 180/Friday, September 17, 2010/Proposed Rules). In vaccines intended for veterinary usage, the potency assay has traditionally been used as a measure of stability. Some potency assays may be acceptable as stability indicating assays, whereas other potency assay will not meet the criteria for stability indicating assays. For example, an ELISA potency test may or may not detect degradation products depending on the specificity of the antisera. With time, the ELISA may overestimate the antigen as partial degradation occurs or if an aggregated or particulate antigen dissociates. Specific assays parameters and attributes that are required for a potency assay to be indicative of serial or reference stability are discussed.

Reverse-mode NCX current in mouse airway smooth muscle: Na(+) and voltage dependence, contributions to Ca(2+) influx and contraction, and altered expression in a model of allergen-induced hyperresponsiveness.

AIM: We examined the electrophysiological properties of reverse-mode Na(+) /Ca(2+) exchange (NCX) in mouse airway smooth muscle (ASM), assessing its contributions to regulation of [Ca(2+) ], and its expression in acute and chronic airway hyperresponsiveness (AHR). METHODS: Membrane currents were studied in single murine ASM cells under voltage clamp at -60 mV using ramp depolarizing commands to +80 mV. Confocal fluorimetric and RT-PCR techniques were used to monitor changes in cytosolic [Ca(2+) ] and NCX expression, respectively. RESULTS: With standard KCl-containing electrode, 30 µm KB-R7943 (an inhibitor of reverse-mode NCX activity) exhibited variable effects on membrane current, indicating modulation of more than one conductance. KB-R7943 activated outwardly rectifying current that was inhibited by 100 µm iberiotoxin (blocker of large-conductance Ca(2+) -dependent K(+) channels), indicating a direct enhancing effect of KB-R7943 on those K(+) channels. After obviating K(+) currents, we found that a current sensitive to 4-4'-diisothiocyanostilbene-2,2'-disulfonic acid (blocker of Ca(2+) -dependent Cl- channels) was markedly increased by elevating [Na(+) ] in the electrode solution to 13, 15.5 and 18 mm and suppressed by KB-R7943, indicating Ca(2+) influx via reverse-mode NCX activity. With conditions preventing Ca(2+) influx through voltage-dependent Ca(2+) channels but promoting that through NCX, we found that introduction of Ca(2+) led to marked but transient KB-R7943-sensitive elevation of [Ca(2+) ]. Additionally, KB-R7943 suppressed cholinergically evoked Ca(2+) waves. Finally, NCX1 expression was not significantly changed in allergen-induced AHR acute model but increased approx. 2.5-fold in a chronic model. CONCLUSION: Reverse-mode NCX activity leads to a physiologically relevant increase in [Ca(2+) ] even under control conditions, and this may be exaggerated in allergen-induced AHR and asthma.

First Report of Boxwood Blight Caused by Cylindrocladium pseudonaviculatum in the United States.

In September and October 2011, a new disease was observed on Buxus spp. in North Carolina and Connecticut, respectively. In North Carolina, over 10,000 containerized Buxus sempervirens (American boxwood) were affected at one location. A few weeks later, the disease was found in Connecticut on entire plantings of B. sempervirens 'Suffruticosa' (English boxwood) at two residential properties, and shortly thereafter on over 150,000 plants at two production nurseries. Initial foliar symptoms appeared as light to dark brown spots, often with dark borders. Spots enlarged and coalesced, often with a concentric pattern, and black streaks or cankers developed on stems. Infected leaves became brown or straw colored and dropped quickly after foliar symptoms were visible. Branch dieback and plant death were also observed in Connecticut. Cultures were isolated from symptomatic leaves and stems and identified as Cylindrocladium pseudonaviculatum Crous, Groenewald & Hill 2002 (1) (syn. Cylindrocladium buxicola Henricot 2002 [2]) on the basis of morphological characteristics. Macroconidiophores were single or in groups of up to three and comprised a stipe, stipe extension, and a penicillate arrangement of fertile branches. The stipe extension was septate, hyaline (89 to 170 × 2 to 4.5 µm), and terminated in an ellipsoidal vesicle (6 to 11 µm diameter) with a papillate or pointed apex. Conidia were cylindrical, straight, hyaline, and one septate (48 to 62 × 4 to 6 µm), occurring in slimy clusters. No microconidiophores were observed. Chlamydospores were medium to dark brown, thick walled, and smooth to rough. Microsclerotia were observed on PDA (1). A portion of ß-tubulin gene sequence from two Connecticut (Genbank Accession Nos. JQ866628 and JQ866629) and two North Carolina isolates showed 100% similarity with only C. pseudonaviculatum strains. USDA-APHIS-PPQ confirmed this new United States record on October 24, 2011. Pathogenicity was confirmed by inoculating three 1-gallon container plants of B. sempervirens 'Suffruticosa' in North Carolina and four liners of B. sinica var. insularis × B. sempervirens 'Green Velvet' in Connecticut with a spore suspension of approximately 5.0 × 106 conidia (North Carolina) or 1.0 × 106 conidia (Connecticut) on the foliage of each plant; untreated control plants were sprayed with water. After incubation at ambient temperature, all inoculated plants developed foliar and stem lesions within 3 to 4 days and blighting occurred within 2 weeks; control plants remained asymptomatic. C. pseudonaviculatum was reisolated from inoculated plants. To our knowledge, this is the first report of C. pseudonaviculatum in the United States. C. pseudonaviculatum causes a serious disease of Buxus spp. in the United Kingdom and several other European countries as well as New Zealand (1). Confirmation of boxwood blight in the United States is significant because of the popularity of boxwood as a landscape plant, and because of the potential economic impact this disease may have on commercial growers; boxwood production in the United States has an annual wholesale market value of approximately $103 million (3). References: (1) P. Crous, et al. Sydowia 54:23, 2002. (2) B. Henricot and A. Culham Mycologia 94: 980, 2002. (3) USDA-NASS, Census of Horticulture, 2010.

Effects of furosemide on allergic asthmatic responses in mice.

BACKGROUND: The syndrome of allergic asthma features reversible bronchoconstriction, airway inflammation and hyperresponsiveness as well as airway remodelling, including goblet cell hyperplasia. Managing severe asthma is still a clinical challenge. Numerous studies report that furosemide, an inhibitor of Na(+)-K(+)-Cl(-) cotransporter (NKCC) reduces airway hyperresponsiveness (AHR) in asthmatic patients. However, the mechanism by which furosemide exerts anti-asthmatic action remains unclear. OBJECTIVE: This study sought to investigate the cellular profile of NKCC1 expression in the lung and examine the effects of furosemide on several outcome measurements in a mouse model of allergic asthma. METHODS: Mice were sensitized and challenged with ovalbumin (OVA). Before challenge, the OVA-sensitized mice were treated with furosemide (4.0 mg/kg/day, via daily intraperitoneal injection for 5 days). Outcome measurements in naïve, OVA-exposure, furosemide-treated naïve and furosemide-treated OVA-exposed mice included the slope of the relationship between inhaled methacholine (MCh) concentration and respiratory system resistance (Slope·R(RS)), bronchoalveolar lavage (BAL) cell counts and immunohistochemical and immunoblotting assays of lung tissues. RESULTS: NKCC1 immunoreactivity was observed in airway epithelial cells (AECs) and alveolar type II (ATII) cells of the control mice. OVA exposure enhanced the expression of NKCC1 in AECs and ATII cells, and increased the infiltration of NKCC1-expressing T lymphocytes in the lung. NKCC1 immunoreactivity was not detected in the airway smooth muscle (ASM) cells. Furosemide treatment reduced the Slope·R(RS) in both naïve and OVA-exposed mice by about 50%. Furosemide treatment also increased T lymphocyte infiltration to the lung in OVA-exposed mice by approximately 53%, but had no effect on pulmonary goblet cell hyperplasia. CONCLUSIONS AND CLINICAL RELEVANCE: Furosemide decreases basal airway responsiveness, thereby reducing the extent of allergen-induced AHR. However, the same treatment also increases T lymphocytes infiltration in the course of allergic asthma. Further studies are necessary to address the usefulness of furosemide in the clinical treatment of asthma.

Modulating progenitor accumulation attenuates lung angiogenesis in a mouse model of asthma.

Asthmatic responses are associated with the lung homing of bone marrow (BM)-derived progenitors implicated as effectors of disease pathology. Studies have shown that increases in lung extracted vascular endothelial progenitor cells (VEPCs) correlate with airway angiogenesis and declining lung function. We investigated the effect of modulating lung homing of VEPCs on tissue remodelling and airway hyperresponsiveness (AHR). BALB/c mice were sensitised to ovalbumin, subjected to a chronic exposure protocol and given early concurrent or delayed treatment with a modulator of progenitor traffic, AMD3100 (CXC chemokine receptor 4 antagonist; inhibits chemotactic activity of stromal-derived factor-1α on VEPCs). After ovalbumin challenge, early haemopoietic stem cells (HSCs) and VEPCs were enumerated along with indices of airway inflammation, lung morphometry and AHR. Following ovalbumin challenge, there was a decrease in BM and an associated increase in the lung tissue-extracted HSCs and VEPCs, together with increases in airway eosinophilia, microvessel density and AHR. These outcomes were significantly inhibited by early concurrent treatment with AMD3100. Where lung disease was established, delayed treatment with AMD3100 significantly attenuated HSC numbers and lung angiogenesis but only partially reversed sustained AHR compared with untreated ovalbumin-exposed mice. Progenitor lung homing is associated with the development of asthma pathology, and early modulation of this accumulation can prevent airway remodelling and lung dysfunction.

The effects of inhaled house dust mite on airway barrier function and sensitivity to inhaled methacholine in mice.

Asthma is functionally characterized by increased airway sensitivity and reactivity. Multiple mechanisms are believed to underlie these functional disorders, including impairment of airway wall barrier function. One proposed mechanism of impaired barrier function is through the direct consequence of proteolytic properties of inhaled allergens, including house dust mite (HDM). Here, we have observed the direct effects of HDM on airway barrier function and response to nebulized or intravenous methacholine. HDM naïve BALB/c mice were anesthetized, exposed to intranasal or intratracheal HDM (15 or 100 µg), and allowed to recover for 30 min or 2 h before methacholine challenge. A separate group of mice was exposed to intratracheal poly-L-lysine (PLL; 100 µg) for a duration of 30 min. This group served as a positive control for the presence of impaired barrier function and airway hypersensitivity. Negative control mice received saline challenges. Outcomes included assessment of lung mechanics in response to nebulized or intravenous methacholine as well as clearance of intratracheally instilled technetium-labeled ((99m)Tc) DTPA to evaluate airway epithelial barrier function. We found that PLL produced a leftward shift in the dose-response curve following nebulized but not intravenous methacholine challenge. This was associated with a significantly faster clearance of (99m)Tc-DTPA, indicating impairment in airway barrier function. However, HDM exposure did not produce changes in these outcomes when compared with saline-exposed mice. These findings suggest that direct impact on airway barrier function does not appear to be a mechanism by which HDM produces altered airway sensitivity in airway disease.

SIGNAL REGULARITY-BASED AUTOMATED SEIZURE DETECTION SYSTEM FOR SCALP EEG MONITORING.

The purpose of the present study was to build a clinically useful automated seizure detection system for scalp EEG recordings. To achieve this, a computer algorithm was designed to translate complex multichannel scalp EEG signals into several dynamical descriptors, followed by the investigations of their spatiotemporal properties that relate to the ictal (seizure) EEG patterns as well as to normal physiologic and artifact signals. This paper describes in detail this novel seizure detection algorithm and reports its performance in a large clinical dataset.

Effect of asthma treatment on fitness, daily activity and body composition in children with asthma.

BACKGROUND: Although several cross-sectional studies have assessed the daily physical activity in children with asthma, the impact of the level of asthma control remains unknown. AIM: To assess the influence of asthma treatment-induced changes in asthma control on daily physical activity, cardiovascular fitness and body composition in children with asthma. METHODS: Daily accelerometer-measured physical activity, cardiovascular fitness, body composition (percent fat, percent lean tissue and bone mineral density) and a variety of asthma outcomes (to assess the level of asthma control) were measured over 4 weeks in 55 children with newly diagnosed untreated asthma and 154 healthy, sex and age-matched controls. Treatment with inhaled corticosteroids was initiated after the baseline period. All outcome measurements were repeated after 1 year and some also during the year of treatment. RESULTS: Asthma control improved markedly during the year of treatment. The improvement in control was associated with a significant increase in total daily activity of 2.8 h/week compared with the healthy controls (P < 0.001). In addition, significant increases were seen in moderate-vigorous activity (33 min/week; P = 0.01) and in cardiovascular fitness (1.2 ml O2/min*kg) compared with the healthy controls. The improvement in activity was mainly seen during the last 6 month of the study. No difference was seen between the two groups in changes in percent body fat. CONCLUSION: Poorly controlled asthma is associated with reduced physical activity and cardiovascular fitness. Improvement in asthma control is associated with a clinically relevant increase in daily physical activity and cardiovascular fitness.

The role of interleukin-4Ralpha in the induction of glutamic acid decarboxylase in airway epithelium following acute house dust mite exposure.

Background Asthma is a disease characterized by airway inflammation, remodelling and dysfunction. Airway inflammation contributes to remodelling, a term that is used to describe structural changes including goblet cell metaplasia (GCM), matrix deposition, and smooth muscle hyperplasia/hypertrophy. GCM has been implicated in asthma mortality by contributing to mucus plugs and leading to asphyxiation. In animal models, this process is highly dependent on IL-13. Recently, we have described an IL-13-dependent up-regulation of a GABAergic signalling system in airway epithelium that contributes to GCM. The mechanism by which IL-13 up-regulates GABA signalling in airway epithelium is unknown. Objectives To test the hypothesis that IL-4Ralpha signalling is required for allergen induced up-regulation of GABAergic signalling and GCM. Methods BALB/c mice were exposed to an acute house dust mite (HDM) protocol and received vehicle, anti-IL-4Ralpha-monoclonal antibody, or control antibody. Outcomes included airway responses to inhaled methacholine (MCh), histology for eosinophilia and GCM, phosphorylated STAT6 levels using immunohistochemistry and immunoblot, and glutamic acid decarboxylase (GAD) 65/67 and GABA(A)beta(2/3) receptor subunit expression using confocal microscopy. Results Acute HDM exposure resulted in increased airway responses to MCh, lung eosinophilia, STAT6 phosphorylation, elevations in GAD65/67 and GABA(A)beta(2/3) receptor expression, and GCM that were inhibited with anti-IL-4Ralpha-monoclonal treatment. Control antibody had no effect. Conclusion The IL-4Ralpha is required for allergen-induced up-regulation of a GABAergic system in airway epithelium implicated in GCM following acute HDM exposure.

Gamma-aminobutyric acid nurtures allergic asthma.

Asthma often occurs as a result of immune-based inflammatory responses, which consequently cause pathological changes in airway structural cells. However, the underlying mechanisms of airway pathology in asthma are still not fully understood. Our recent studies revealed a critical role of gamma-aminobutyric acid (GABA) signalling pathway in the airway epithelium of allergic asthma through its ability to stimulate mucus production. This review briefly describes the GABAergic signalling system and its role in the regulation of mucus protein production in bronchial airway epithelial cells.

Role of STAT6 and SMAD2 in a model of chronic allergen exposure: a mouse strain comparison study.

BACKGROUND: Asthma is a disease characterized by variable and reversible airway obstruction and is associated with airway inflammation, airway remodelling (including goblet cell hyperplasia, increased collagen deposition and increased smooth muscle mass) and increased airway responsiveness. It is believed that airway inflammation plays a critical role in the development of airway remodelling, with IL-13 and TGF-beta1 pathways being strongly associated with the disease progression. Mouse models of asthma are capable of recapitulating some components of asthma and have been used to look at both IL-13 and TGF-beta1 pathways, which use STAT6 and SMAD2 signalling molecules, respectively. OBJECTIVES: Using brief and chronic models of allergen exposure, we utilized BALB/c and C57Bl/6 to explore the hypothesis that observed differences in responses to allergen between these mouse strains will involve fundamental differences in IL-13 and TGF-beta1 responses. METHODS: The following outcome measurements were performed: airway physiology, bronchoalveolar lavage cell counts/cytokine analysis, histology, immunoblots and gene expression assays. RESULTS: We demonstrate in BALB/c mice an IL-13-dependent phosphorylation of STAT6, nuclear localized in inflammatory cells, which is associated with indices of airway remodelling and development of airway dysfunction. In BALB/c mice, phosphorylation of SMAD2 is delayed relative to STAT6 activation and also involves an IL-13-dependent mechanism. In contrast, despite an allergen-induced increase in IL-4, IL-13 and eosinophils, C57Bl/6 demonstrates a reduced and distinct pattern of phosphorylated STAT6, no SMAD2 phosphorylation changes and fail to develop indices of remodelling or changes in airway function. CONCLUSION: The activation of signalling pathways and nuclear translocation of signalling molecules downstream of IL-13 and TGF-beta1 further support the central role of these molecules in the pathology and dysfunction in animal models of asthma. Activation of signalling pathways downstream from IL-13 and TGF-beta1 may be more relevant in disease progression than elevations in airway inflammation alone.

Budesonide prevents but does not reverse sustained airway hyperresponsiveness in mice.

Despite the effectiveness of corticosteroids at resolving airway inflammation, they are only moderately effective at attenuating airway hyperresponsiveness (AHR). The extent to which corticosteroids are able to reverse or inhibit the development of sustained AHR is not known. The present study aimed to determine whether budesonide can resolve and or prevent the development of sustained AHR in mice. Mice were chronically exposed to allergen and treated with budesonide either: 1) briefly during the final weeks of exposure to allergen; 2) prolonged concurrently throughout exposure to allergen; or 3) delayed following final exposure to allergen. AHR was assessed 24 h (brief treatment) or 4 weeks (prolonged concurrent and delayed treatments) following final exposure to allergen. Brief budesonide intervention significantly attenuated the inflammation-associated AHR assessed immediately following final exposure to allergen. Similarly, prolonged concurrent budesonide treatment prevented the development of sustained AHR. Delayed budesonide intervention, however, did not resolve sustained AHR. In conclusion, the early introduction and, importantly, the persistence of corticosteroid treatment prevented the development of sustained airway hyperresponsiveness; however, the inability of corticosteroids to reverse established airway dysfunction indicates a limitation in their use for the complete, long-term management of airway hyperresponsiveness.

Effects of allergen on airway narrowing dynamics as assessed by lung-slice technique.

Asthma is characterised by an excessive airway narrowing in response to a variety of stimuli, called airway hyperresponsiveness (AHR). Previous comparisons between mouse strains have shown that increased velocity of airway narrowing correlates with baseline airway responsiveness. These data prompted the investigation into models of induced AHR to see whether airway narrowing dynamics correlated with in vivo responsiveness. In an attempt to reproduce some of the features of asthma, BALB/c mice were sensitised and subjected to either brief or chronic periods of allergen exposure. Brief exposure involved two challenges with intranasal chicken egg ovalbumin (OVA(in)). Chronic exposure involved six 2-day periods of OVA(in) challenges, each separated by 12 days. Control mice received intranasal saline challenges. Outcomes included videomicrometry of lung slices (magnitude and velocity of airway narrowing), in vivo respiratory physiology measurements and histological staining with morphometric analysis. Neither brief nor chronic allergen exposure resulted in greater airway narrowing and increased velocity compared with saline controls. Structural changes in the airway, such as goblet cell hyperplasia, subepithelial fibrosis and increased contractile tissue, were detected in mice chronically challenged with allergen. In conclusion, increased responsiveness to methacholine following allergen challenge may not be due to an intrinsic change to the smooth muscle per se, but rather to other changes in the lung, which ultimately manifest as an increase in respiratory resistance.

Three-dimensional computed tomography imaging in an animal model of emphysema.

Emphysema is a major health problem and novel drugs are needed. Animal disease models are pivotal in their development, but the validity and sensitivity of current tools for the evaluation of drug efficacy is limited. The usefulness of micro computed tomography (CT) as an innovative tool to assess emphysema in a mouse model was investigated. Serial CT scans were performed in bi-weekly intervals in Smad3 knockout (KO) mice, which spontaneously develop airspace enlargement. Lung density was quantified in two- and three-dimensional images and correlated to mean linear intercept and lung compliance. CT scans of Smad3 KO lungs revealed a significant decrease in lung density at age 8 weeks and a further progression at age 14 weeks with respect to age-matched wild-type (WT) animals. Emphysema could be reliably assessed with both the two- and three-dimensional approach, but the three-dimensional approach was superior, due to normalisation to lung volumes and less variability. Lung compliance by week 14 was 0.053+/-0.005 and 0.034+/-0.002% of maximum volume.cmH(2)O(-1) for KO and WT mice, respectively, reflecting significant physiologically relevant emphysema. Small animal computed tomography imaging and density quantification in a reconstructed three-dimensional image is a useful tool for quantifying emphysematous changes in an animal disease model. It adds significant information to conventional assessment.