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A low quadriceps slow-twitch (ST), oxidative (relative to fast-twitch) fiber proportion is prevalent in chronic diseases such Chronic Obstructive Pulmonary Disease (COPD) and is associated with exercise limitation and poor outcomes. Benefits of an increased ST fiber proportion are demonstrated in genetically modified animals. Pathway analysis of published data of differentially expressed genes in mouse ST and FT fibers, mining of our microarray data and a qPCR analysis of quadriceps specimens from COPD patients and controls were performed. ST markers were quantified in C2C12 myotubes with EGF-neutralizing antibody, EGFR inhibitor or an EGFR-silencing RNA added. A zebrafish egfra mutant was generated by genome editing and ST fibers counted. EGF signaling was (negatively) associated with the ST muscle phenotype in mice and humans, and muscle EGF transcript levels were raised in COPD. In C2C12 myotubes, EGFR inhibition/silencing increased ST, including mitochondrial, markers. In zebrafish, egfra depletion increased ST fibers and mitochondrial content. EGF is negatively associated with ST muscle phenotype in mice, healthy humans and COPD patients. EGFR blockade promotes the ST phenotype in myotubes and zebrafish embryos. EGF signaling suppresses the ST phenotype, therefore EGFR inhibitors may be potential treatments for COPD-related muscle ST fiber loss.

Skeletal muscle dysfunction is a frequent extra-pulmonary manifestation of Chronic Obstructive Pulmonary Disease (COPD) with implications for both quality of life and survival. The underlying biology nevertheless remains poorly understood. We measured global gene transcription in the quadriceps using Affymetrix HuGene1.1ST arrays in an unselected cohort of 79 stable COPD patients in secondary care and 16 healthy age- and gender-matched controls. We detected 1,826 transcripts showing COPD-related variation. Eighteen exhibited ≥2fold changes (SLC22A3, FAM184B, CDKN1A, FST, LINC01405, MUSK, PANX1, ANKRD1, C12orf75, MYH1, POSTN, FRZB, TNC, ACTC1, LINC00310, MYH3, MYBPH and AREG). Thirty-one transcripts possessed previous reported evidence of involvement in COPD through genome-wide association, including FAM13A. Network analysis revealed a substructure comprising 6 modules of co-expressed genes. We identified modules with mitochondrial and extracellular matrix features, of which IDH2, a central component of the mitochondrial antioxidant pathway, and ABI3BP, a proposed switch between proliferation and differentiation, represent hubs respectively. COPD is accompanied by coordinated patterns of transcription in the quadriceps involving the mitochondria and extracellular matrix and including genes previously implicated in primary disease processes.

Human pain models invoking central sensitization, one of the key mechanisms of chronic pain, may be useful for characterizing new analgesics. A new model of electrical hyperalgesia can detect the efficacy of several analgesic mechanisms. Because IV adenosine can alleviate neuropathic pain, we investigated its effect on experimental sensitization. This was a double-blinded, randomized, two-period crossover study in 20 healthy volunteers. Current pulses (0.5 ms; 1 Hz) were applied intracutaneously to achieve pain rating of approximately 5 on a 0-10 numeric rating scale. Pain, areas of pinprick hyperalgesia, and tactile allodynia were assessed during the 2.5-h stimulation period. Adenosine (50 microg. kg(-1). min(-1)) and placebo were infused IV over 60 min. Additional testing was performed 24 h after each treatment. Adenosine reduced the area of pinprick hyperalgesia during the infusion compared with placebo; there was no significant effect on tactile allodynia or pain rating. The effect on hyperalgesia developed over 15 min and was significant (P < or = 0.05) for the rest of the infusion period. There was no difference between treatments at 24 h. Thus, in accordance with reports on neuropathic pain, adenosine reduced central sensitization in the human model of electrical hyperalgesia. However, adenosine did not have the long-term effects seen in patients. The model can investigate mechanisms of drugs for the treatment of chronic pain.

BACKGROUND Tumour necrosis factor (TNF) is a potent pro-inflammatory cytokine which is prominent in asthmatic airways. TNF shows genetic variations in secretion which are linked to polymorphisms in the TNF gene complex and the surrounding major histocompatibility (MHC) locus. These polymorphisms do not seem to be themselves functionally important. In these circumstances, the identification of disease associated haplotypes (combination of alleles on individual chromosomes) may narrow the search for polymorphisms which alter gene function. METHODS TNF-308, LTα Nco I, and HLA-DRB1 polymorphisms were investigated for association with asthma, bronchial responsiveness, and medication use in 1004 subjects in 230 families from a general population sample. RESULTS The common LTα Nco I*1/TNF-308*2/HLA-DRB1*03 haplotype, which was present in 11% of unrelated individuals, was weakly associated with asthma (OR = 1.38, p = 0.016, corrected for familial correlation). The rarer LTα Nco I*1/TNF-308*2/HLA-DRB1*02 haplotype, which was found in 0.6% of unrelated subjects, was more strongly associated with asthma (OR = 6.68, p = 0.002). This haplotype also showed association with bronchial hyperresponsiveness (OR = 21.9, p = 0.0000) and the use of inhaled or oral steroids (OR 8.0, p = 0.04). CONCLUSIONS The results of this study show only two extended TNF/HLA-DR haplotypes to be associated with asthma. The search for functional alleles responsible for an increased risk of asthma should concentrate on the LTα Nco I*1/TNF-308*2/HLA-DRB1*02 haplotype.

NIDDM has a strong genetic component, as evidenced by the high level of concordance between identical twins. The nature of the genetic predisposition has remained largely unknown. Recently, the glucokinase gene locus on chromosome 7p has been shown to be linked to a subtype of NIDDM known as MODY in French and British pedigrees, and glucokinase mutations have been identified. To study the relationship between the glucokinase gene and NIDDM, we performed a linkage analysis in 12 Caucasian pedigrees ascertained through a proband with classical NIDDM. The LINKAGE program was used under four models, including autosomal dominant and recessive, with individuals with glucose intolerance counted as either affected or of unknown status. Linkage was significantly rejected with the dominant models (LOD scores −4.65, −4.25), and was unlikely with the recessive model when glucose intolerance was considered as affected (LOD score −1.38). These findings suggest that mutations in or near the glucokinase gene are unlikely to be the major cause of the inherited predisposition to NIDDM in Caucasian pedigrees, but do not exclude a role for this locus wit a polygenic model, or a major role in some pedigrees.

Background: Initial studies by positional cloning have identified the genes encoding the plant homeodomain zinc finger protein 11 (PHF11) and dipeptidyl-peptidase 10 (DPP10) as asthma susceptibility genes. The variants in the two genes have been associated with asthma in several populations of European or Latin American origin. Objective: The aim of this study was to assess the common PHF11 and DPP10 polymorphisms for associations to asthma and asthma-related traits in a Han Chinese population. Methods: We genotyped six polymorphic markers in PHF11 and five polymorphic markers in DPP10 in a Han Chinese case-control cohort consisting of 408 asthma patients and 288 unrelated disease-free controls recruited from the Northern region of China. We analyzed the association between these markers and asthma as well as a number of intermediate, asthma-related traits. Linkage disequilibrium and haplotype patterns were also evaluated. Results: Significant associations were identified between two makers in PHF11 (rs1046295 and rs16659) and asthma susceptibility (odds ratio, OR = 1.32, 95% con fidence interval, CI = 1.06–1.65, p = 0.0096, for rs1046295, and OR = 1.41, 95% CI = 1.12–1.75, p = 0.0026, for rs16659). A strong association was observed between an SNP in DPP10 (rs10208402) and loge-transformed total IgE (p = 0.0003) and the percentage of peripheral blood eosinophils (p = 0.0023). A weak association between rs1430090 in DPP10 and forced expiratory volume in 1 s was also observed (p = 0.048). Haplotype analysis revealed two protective haplotypes in PHF11 against asthma. Conclusion: The results provide supporting evidence for genetic variants in PHF11 and DPP10 genes underlying asthma susceptibility and asthma-related quantitative traits in a Han Chinese population.

The Class II genes of the MHC represent a major locus with quantified effects on atopic (allergic) phenotypes in many studies of westernized Caucasians. Although asthma is considered a disease of western societies, typical components of the asthma phenotype, such as elevations of the IgE, are seen with parasitic infestation. We have therefore investigated the effects of the HLA-DRB1 locus on asthma and its intermediate phenotypes in Aboriginal people from the Kimberly region of Australia who were suffering from endemic hookworm infection. Recognizable correlates of allergic asthma were present in the subjects, including skin test positivity to house dust mite (HDM), specific IgE responses to HDM, and the total serum IgE. HLA-DRB1 alleles did not predict the presence of asthma, but multi-allelic tests of association showed the locus accounted for approximately 33% of the variance of the total serum IgE concentration and 17% of the variance of the specific IgE titres to HDM. Genetic admixture was excluded as a cause of the results. These effects of the MHC on IgE levels were an order of magnitude greater than that seen in Caucasians, consistent with the hypothesis that the genetic predisposition to allergic disease may be driven by adaptation to helminth infection. The results further suggest that parasitism per se is not protective against asthma.

Polymorphisms within the beta subunit of the high-affinity receptor for IgE (Fc epsilon R1-beta ) on chromosome 11q13 have been related to atopy and asthma and the lymphotoxin alpha (LT alpha) gene on chromosome 6 is implicated in asthma.To elucidate the association of polymorphisms in the Fc epsilon R1-beta and LT alpha genes to IgE responses and asthma in a family-orientated rural population.A total of 461 adult farmers, who participated in an epidemiological follow-up study on respiratory symptoms among farmers on the Swedish island of Gotland, were examined. The traits assessed included serum total IgE, IgE antibody responses to 21 common inhalant allergens and asthma.The 237G mutation was only detected in seven persons. Atopy was found to be associated with the RsaI-ex7 AB-genotype (OR = 1.9; P = 0.04). The RsaI-ex7 B allele had a significant influence on IgE responses to pollens and dust mites (OR = 5.5; P = 0.03 and OR = 5.2; P = 0.049, respectively). The influence of this allele was stronger when the association towards single dust mite species (Lepidoglyphus destructor) was estimated (OR = 7.1, P = 0.03) and the association increased even more when the major allergen of L. destructor (rLep d 2) was analysed (OR = 11.2, P = 0.02). These associations were independent of sex, age and smoking, and the estimates of RsaI-in2 independent of RsaI-ex7. RsaI-in2, RsaI-ex7 and LT alpha genotypes were unassociated with total serum IgE. No significant difference in the distribution of RsaI-in2, RsaI-ex7 and LT alpha genotypes was found among subjects with atopy or asthma compared to healthy controls.This study supports the notion that polymorphisms in the Fc epsilon R1-beta gene have significant effects on IgE responsiveness. Secondly, dust mites in rural populations influence the expression of genes on chromosome 11q13.

Malignant neoplasia of the lung or pleura is a com mon and serious complication of exposure to asbes tos1 and necessitates careful surveillance of those at risk. The assessment of a pulmonary mass lesion after exposure to asbestos is complicated by the occurrence of pulmonary "pseudotumours." These result from pleural fibrosis and entrapment of the lung parenchyma (Blesovsky's syndrome.23). We report asymmetric rapidly progressive fibrosis of the upper lobe of the lung as another cause of apparent lung malignancy after exposure to asbestos.

The alveolar accumulation of protein and angiotensin converting enzyme activity was compared with the development of right ventricular hypertrophy in male rats after different periods of monocrotaline exposure. Total doses of monocrotaline were varied by dividing the animals into three groups in which ingestion was limited to three, seven, and 15 days. These groups were studied 21 days after the start of monocrotaline exposure and compared with a group treated continuously for 28 days. The total lung weight increased after three or more days of treatment, while after seven days there was significant alveolar accumulation of protein, which was paralleled by an increase in angiotensin converting enzyme activity in alveolar lavage fluid. Identical changes also occurred after 15 and 28 days of exposure to monocrotaline. Lung angiotensin converting enzyme activity was decreased after three days' ingestion of monocrotaline and did not alter further with longer periods of exposure. None of these effects of monocrotaline in the three and seven day treatment groups was associated with right ventricular hypertrophy, which occurred only in animals treated for 15 or more days. The effects of monocrotaline ingestion on the lung were dose related and had no causal relationship to the development of right ventricular hypertrophy.

Acute pulmonary oedema can be induced by intraperitoneal injection of Escherichia coli endotoxin in the mouse. A fall in serum angiotensin converting enzyme activity is found in mice given endotoxin and in patients with septic adult respiratory distress syndrome, and has been proposed as an indicator of lung microvascular injury. Protein concentration and angiotensin converting enzyme activity in serum, lung, and bronchoalveolar lavage fluid were determined in male mice up to eight hours after injection of endotoxin. By six hours the serum protein concentration had increased and the bronchoalveolar lavage fluid protein concentration had fallen, suggesting fluid shift into the lung. Angiotensin converting enzyme activity fell in serum and lung but increased in bronchoalveolar lavage fluid. As these changes in enzyme activity were not paralleled by changes in protein concentration they are unlikely to be a result of fluid shift or protein leak, and may indicate an active role of the enzyme in the response to sepsis.

Peripheral eosinophil counts were measured at intervals before and after control and allergen inhalation in 14 asthmatic subjects. A relative fall in eosinophil counts was noted 9 h after allergen challenge, in contrast to the diurnal increase seen on the control day (p = 0.005). This fall in eosinophil count correlated strongly with the magnitude of the late asthmatic response (r = -0.72, p = 0.003) and with the changes in bronchial responsiveness to histamine at 3 and 24 h after allergen was given (r = 0.54, p = 0.044 and r = 0.82, p less than 0.001, respectively). The findings demonstrate eosinophil kinetics are related to the occurrence of late-phase reactions and to the associated worsening of bronchial hyperreactivity.

In 105 subjects taken from a student population and aged between 15 and 30 there was a strong positive association between the presence of the atopic state, defined by skin tests, and a high level of non-specific bronchial responsiveness to methacholine (chi 2 = 10.5, d.f. = 2, P = 0.01). Regression analysis showed a history of asthma, and the symptom of wheeze, to be predominantly predicted by the degree of bronchial responsiveness (R2 = 31%), with only a minor independent contribution from the degree of atopy (R2 a further 5%). The genetic or other reasons for the association between bronchial responsiveness and atopy may have importance in understanding the aetiology of allergic asthma.

Changes in airway responsiveness to histamine after allergen inhalation challenge were studied in 14 nonsmoking atopic adult subjects with asthma. Inhalation challenges with allergen and with phosphate-buffered saline (control challenge) were performed single blind in random order, with an interval of 14 days. The development of a late asthmatic response was accompanied by an increase in airway histamine responsiveness that was significant when it was compared with the airway histamine responsiveness after the control challenge at 3 hours (p less than 0.01), 24 hours (p less than 0.01), and 48 hours (p less than 0.02), with recovery at 2 weeks after allergen inhalation. The 3-hour changes in airway responsiveness occurred independently of changes in airway caliber and correlated with the magnitude of the subsequent late response (r = 0.86; p less than 0.001). These results suggest that the tissue events (possibly airway inflammation) that underlie the late asthmatic response may occur before this response becomes clinically apparent.