Profile of gene expression in a murine model of allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) results from the interactions of the Aspergillus allergens and immune system of the patients. We studied the gene expression profile in a mouse model of ABPA. Of the 12,000 genes studied, 1,300 genes showed enhanced expression and represent chemokine, cytokine, growth factor, signal transduction, and transmembrane receptor genes as well as genes related to arginine metabolism.     

Voice abnormality in adults with congenital and adult-acquired growth hormone deficiency

CONTEXT: Adult males with congenital, untreated, severe GH deficiency (GHD) due to genetic GHRH receptor deficiency exhibit distinctive, high-pitched, and raspy voice characteristics. OBJECTIVE/DESIGN: To determine the physical underpinning of this phenomenon, we performed voice recordings, translarynx impedance measurements, spectral analysis, and estimates of spectral complexity [approximate entropy (ApEn)] in four affected men. Results were compared with those obtained in four men with untreated adult-onset GHD and a normal male population. RESULTS: Congenital GHD subjects had a high-pitched voice with a fundamental frequency typical of normal females (174-266 Hz). Their frequency spectra were characterized by abnormal harmonics, with reversal/interruption of the normal amplitude decay among higher-order harmonics, findings consistent with a creaky quality of the voice. Patients with adult-onset GHD, acquired at ages 31, 38, and 40 yr, had a normal male pitch (fundamental frequency, 117-154 Hz) but pathologically low ApEn values, corresponding to a breathy quality of the voice and suggesting abnormal vocal fold function. A fourth patient who acquired GHD at age 22 yr had a pitch intermediate between male and female, high ApEn, and a spectral pattern similar to the congenital GHD patients. CONCLUSIONS: This study demonstrates an effect of GH on laryngeal size and vocal fold compliance that results in a high pitch and disordered spectral quality. The time of onset of GHD determines which type of abnormality predominates.     

Stimulus-controlled delivery of drugs and genes

Macromolecular and colloidal systems used for the systemic delivery of drugs and genes promise to improve the way we treat and prevent numerous diseases. New generations of drug and gene delivery systems (DGDS) are being designed to enhance further efficiency by using a range of endogenous and external stimuli. This review focuses on three qualitatively distinct ways a stimulus can improve the efficiency of DGDS; namely, by selectively triggering release of the therapeutic agent from the DGDS, by modulating physical properties of DGDS and by favourably altering physiological properties of tissues to enhance DGDS transport. Recent developments in these areas are discussed to illustrate the potential of stimulus-controlled DGDS in the development of new generations of therapeutics.     

Preserved or slightly depressed ejection fraction and outcomes after myocardial infarction

BACKGROUND Left ventricular ejection fraction (EF) in post-myocardial infarction (MI) patients is a strong predictor of adverse cardiovascular events. Although resting EF as measured by transthoracic echocardiography (TTE), contrast ventriculography (CNV), and radionuclide angiography (RNA) exhibit high correlation, there is only modest agreement between these modalities. This study sought to explore whether modality of EF assessment influences prognostication of post-MI patients with normal or slightly reduced EF. METHODS AND RESULTS The National Heart, Lung, and Blood Institute (NHLBI) limited access dataset of the Prevention of Events with Angiotensin Converting Enzyme Inhibition (PEACE) Trial (1996-2003, n=8290) comparing trandolapril versus placebo was used. The cohort was partitioned into TTE (n=2582), RNA (n=816), and CNV (n=1155) groups based on modality of EF assessment. EF was a significant predictor of cardiovascular mortality (HR 0.97, 95% CI 0.95 to 0.98; p<0.005) and all cause mortality (HR 0.98, 95% CI 0.97 to 0.99; p=0.0002) on multivariate analysis in this population with preserved or mildly depressed EF. Although CNV, TTE, and RNA groups differed significantly in terms of baseline variables, no appreciable differences were noted between RNA (HR 1.13, 95% CI 0.85 to 1.50; ns) and CNV (HR 1.13, 95% CI 0.99 to 1.27; ns) groups, compared with TTE for all cause mortality. Similarly, no significant differences were observed for cardiovascular mortality between RNA (HR 1.23, 95% CI 0.82 to 1.84; p=0.31) and CNV (HR 1.14, 95% CI 0.78 to 1.67, p=0.49) versus TTE. CONCLUSION EF is a significant predictor of all-cause mortality and cardiovascular mortality in patients with preserved or mildly depressed EF. Modalities of EF measurement are interchangeable and do not play a significant role in prognostication in a post-MI population.     

Nitration of N-methyl-D-aspartate receptor subunits following in vitro dephosphorylation of cerebral cortical membranes of newborn piglets.

Previous studies have shown that activity of the cerebral N-methyl-D-aspartate (NMDA) receptor is modified by receptor nitration and phosphorylation. Since the sites for tyrosine phosphorylation and nitration are on adjacent carbon atoms, the present study tested the hypothesis that in vitro dephosphorylation of the NR1, NR2A and NR2B subunits of the NMDA receptor increases receptor nitration by peroxynitrite in cortical membranes of newborn piglets. To test this hypothesis, cerebral cortical P(2) membranes were prepared from normoxic and hypoxic newborn piglets and divided into dephosphorylated and non-dephosphorylated control groups. Dephosphorylation was performed in vitro by incubation with protein tyrosine phosphatase 1B and confirmed by immunoprecipitation with antiphosphotyrosine antibody. Dephosphorylated and non-dephosphorylated samples were nitrated with 0.5 mM peroxynitrite. Nitration was measured by immunoprecipitating with agarose-conjugated anti-nitrotyrosine antibody followed by Western blot analysis using specific anti -NR1, -NR2A and -NR2B primary antibodies. The data demonstrate that nitration of the NR1, NR2A and NR2B subunits of the NMDA receptor increases following dephosphorylation in both normoxic and hypoxic animals, however increase is much higher in hypoxic animals. We conclude that dephosphorylation at the site adjacent to the nitration site (ortho-position) on tyrosine residues of the NMDA receptor enhances nitration. Since in vitro nitration of the NMDA receptor increases the affinity of the glutamate recognition site and the receptor ion channel, we speculate that tyrosine dephosphorylation of the NMDA receptor will remove steric hindrance and facilitate nitration of tyrosine residues resulting in increased ion-channel activation in the hypoxic newborn brain.     

DNA polymerase β deficiency is linked to aggressive breast cancer: A comprehensive analysis of gene copy number,mRNA and protein expression in multiple cohorts

Short arm of chromosome 8 is a hot spot for chromosomal breaks, losses and amplifications in breast cancer. Although such genetic changes may have phenotypic consequences, the identity of candidate gene(s) remains to be clearly defined. Pol β gene is localized to chromosome 8p12‐p11 and encodes a key DNA base excision repair protein. Pol β may be a tumour suppressor and involved in breast cancer pathogenesis. We conducted the first and the largest study to comprehensively evaluate pol β in breast cancer. We investigated pol β gene copy number changes in two cohorts (n = 128 & n = 1952), pol β mRNA expression in two cohorts (n = 249 & n = 1952) and pol β protein expression in two cohorts (n = 1406 & n = 252). Artificial neural network analysis for pol β interacting genes was performed in 249 tumours. For mechanistic insights, pol β gene copy number changes, mRNA and protein levels were investigated together in 128 tumours and validated in 1952 tumours. Low pol β mRNA expression as well as low pol β protein expression was associated high grade, lymph node positivity, pleomorphism, triple negative, basal‐like phenotypes and poor survival (ps < 0.001). In oestrogen receptor (ER) positive sub‐group that received tamoxifen, low pol β protein remains associated with aggressive phenotype and poor survival (ps < 0.001). Artificial neural network analysis revealed ER as a top pol β interacting gene. Mechanistically, there was strong positive correlation between pol β gene copy number changes and pol β mRNA expression (p < 0.0000001) and between pol β mRNA and pol β protein expression (p < 0.0000001). This is the first study to provide evidence that pol β deficiency is linked to aggressive breast cancer and may have prognostic and predictive significance in patients.     

Overexpression of Bcl-2 as a proxy redox stimulus to enhance activity of non-viral redox-responsive delivery vectors

Redox-sensitive non-viral delivery systems exploit intracellular reducing environment to improve the efficacy of the delivery of nucleic acids by selectively releasing the cargo in the subcellular space. Bcl-2 overexpression is frequently observed in human cancers and is closely associated with increased resistance to chemotherapy and radiotherapy. One of the biochemical alterations accompanying Bcl-2 overexpression is the increase in cellular glutathione (GSH) levels. In this study, we hypothesize that such increase of GSH concentration will selectively enhance the transfection activity of redox-sensitive delivery systems in cells overexpressing Bcl-2. Transfection studies were conducted in MCF-7 mammary carcinoma cells and MCF-7 clones overexpressing Bcl-2. It was confirmed that Bcl-2 overexpression resulted in the expected increase in GSH concentration. Redox-sensitive complexes containing plasmid DNA, mRNA, antisense oligodeoxynucleotides, and siRNA exhibited selectively increased activity in cells overexpressing Bcl-2 compared to non-redox complexes. The effect of Bcl-2 overexpression on the selective enhancement of transfection was highly dependent on the type of the delivered nucleic acid, and was most pronounced for mRNA. This study shows that Bcl-2 overexpression can serve as a proxy redox stimulus to enhance the activity of all major classes of potential nucleic acid therapeutics, when delivered using redox-sensitive vectors.     

A118G mu opioid receptor polymorphism among drug addicts in Malaysia

Drug addiction is an important social problem in many countries. Genetic and environmental factors contribute to the predisposition of drug addiction. Genetic variations at the μ opioid receptor (OPRM1) gene locus have been associated with opiate addiction. The present study aims to delineate the frequency of A118G allele of OPRM1 among Malaysian subjects. The frequency of A allele and G allele were 51% and 49%, respectively for addicts and about 73% and 27% respectively for healthy volunteers. The frequency of G allele was 1.77-fold higher in addicts by odds ratio calculation at 95% Cl, which indicate the G allele to be strongly associated with addiction X(2) = 15.31,P < 0.0001; odds ratio 2.51; 95% Cl (1.575-3.994), compared to healthy volunteers. A significant association was observed between A118G polymorphism in μ opioid receptor gene and drug addiction.