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author:("Das, allan")
1.  A qualitative study of the attitudes of patients in an early intervention service towards antipsychotic long-acting injections 
The objective of this study was to investigate attitudinal themes to antipsychotic long-acting injections (LAIs) in patients in an early intervention team (EIT).
Interviews were carried out with outpatients purposively sampled from an EIT to represent patients currently prescribed antipsychotic LAIs, oral antipsychotics and those not prescribed antipsychotic medication. Interviews were conducted and analysed according to grounded theory. Recruitment stopped when saturation of themes was reached.
Interviews from 11 patients were analysed (median age 24 years). Attitudes to LAIs were condensed into three key categories: therapeutic alliance and the psychiatrists’ recommendation of antipsychotic medication; patients’ knowledge and beliefs about LAIs; and patients’ views regarding the appropriateness of LAIs. Participants valued their psychiatrist’s recommendation as to the most appropriate antipsychotic. Attitudes to LAIs varied but were most positive among those currently receiving a LAI. Among those not prescribed LAIs, some were open to considering a LAI if their clinician recommended it but others were opposed to such treatment and preferred tables. There was a lack of awareness of LAIs as a treatment option among those not prescribed a LAI. Delay in being offered a LAI was reported in the group currently prescribed a LAI. Several participants associated oral antipsychotics, LAIs and mental illness with stigma. Some not prescribed a LAI had misperceptions about the nature of this treatment. Participants regarded the advantages of LAIs as convenience and avoiding forgetting to take tablets, while disadvantages included injection pain, fear of needles and coercion.
Lack of knowledge, misperceptions and stigma related to LAIs and other treatment options should be addressed by providing patients with accurate information. This will facilitate patients being involved in choices about treatment, and should they decide to accept medication, which drug and formulation is most appropriate for their needs. Clinicians should avoid making assumptions about patients’ attitudes to LAIs; attitudes vary but some early intervention patients not prescribed LAIs are open to considering this treatment. Antipsychotic prescribing should result from a shared decision-making process in which clinicians and patients openly discuss the pros and cons of different formulations and drugs. The themes identified in this qualitative study require further exploration using quantitative methodology.
PMCID: PMC4212491  PMID: 25360242
adherence; antipsychotics; attitudes; depot; first-episode psychosis; long-acting injection; schizophrenia
3.  Inhibition of ROS-induced apoptosis in endothelial cells by nitrone spin traps via induction of phase II enzymes and suppression of mitochondria-dependent pro-apoptotic signaling 
Biochemical Pharmacology  2012;84(4):486-497.
Oxidative stress is the main etiological factor behind the pathogenesis of various diseases including inflammation, cancer, cardiovascular and neurodegenerative disorders. Due to the spin trapping abilities and various pharmacological properties of nitrones, their application as therapeutic agent has been gaining attention. Though the antioxidant properties of the nitrones are well known, the mechanisms by which they modulate the cellular defense machinery against oxidative stress is not well investigated and requires further elucidation. Here, we have investigated the mechanisms of cytoprotection of the nitrone spin traps against oxidative stress in bovine aortic endothelial cells (BAEC). Cytoprotective properties of both the cyclic nitrone 5,5-dimethyl-pyrroline N-oxide (DMPO) and linear nitrone alpha-phenyl N-tert-butyl nitrone (PBN) against H2O2-induced cytoxicity were investigated. Preincubation of BAEC with PBN or DMPO resulted in the inhibition of H2O2–mediated cytotoxicity and apoptosis. Nitrone-treatment resulted in the induction and restoration of phase II antioxidant enzymes via nuclear translocation of NF-E2-related factor 2 (Nrf-2) in oxidatively-challenged cells. Furthermore, the nitrones were found to inhibit the mitochondrial depolarization and subsequent activation of caspase-3 induced by H2O2. Significant down-regulation of the pro-apoptotic proteins p53 and Bax, and up-regulation of the anti-apoptotic proteins Bcl-2 and p-Bad were observed when the cells were preincubated with the nitrones prior to H2O2–treatment. It was also observed that Nrf-2 silencing completely abolished the protective effects of nitrones. Hence, these findings suggest that nitrones confer protection to the endothelial cells against oxidative stress by modulating phase II antioxidant enzymes and subsequently inhibiting mitochondria-dependent apoptotic cascade.
PMCID: PMC3402614  PMID: 22580046
nitrones; spin traps; oxidative stress; endothelial dysfunction; Nrf-2
4.  Smokeless Tobacco Extract (STE)-Induced Toxicity in Mammalian Cells is Mediated by the Disruption of Cellular Microtubule Network: A Key Mechanism of Cytotoxicity 
PLoS ONE  2013;8(7):e68224.
Smokeless tobacco usage is a growing public health problem worldwide. The molecular mechanism(s) underlying smokeless tobacco associated tissue damage remain largely unidentified. In the present study we have tried to explore the effects of aqueous extract of smokeless tobacco (STE) on tubulin-microtubule, the major cytoskeleton protein that maintains cells morphology and participates in cell division. Exposure to STE resulted in dose-dependent cytotoxicity in a variety of mammalian transformed cell lines such as human lung epithelial cells A549, human liver epithelial cells HepG2, and mouse squamous epithelial cells HCC7, as well as non-tumorogenic human peripheral blood mononuclear cells PBMC. Cellular morphology of STE-treated cells was altered and the associated disruption of microtubule network indicates that STE targets tubulin-microtubule system in both cell lines. Furthermore it was also observed that STE-treatment resulted in the selective degradation of cellular tubulin, whereas actin remains unaltered. In vitro, polymerization of purified tubulin was inhibited by STE with the IC50 value∼150 µg/ml and this is associated with the loss of reactive cysteine residues of tubulin. Application of thiol-based antioxidant N-acetyl cysteine (NAC) significantly abrogates STE-mediated microtubule damage and associated cytotoxicity in both A549 and HepG2 cells. These results suggest that microtubule damage is one of the key mechanisms of STE-induced cytotoxity in mammalian cells.
PMCID: PMC3708936  PMID: 23874548
5.  Rabs and the Exocyst in Ciliogenesis, Tubulogenesis, and Beyond 
Trends in cell biology  2011;21(7):383-386.
The exocyst -- an octameric protein complex mediating vesicle tethering at the plasma membrane for exocytosis -- is a downstream effector of the Rab proteins Rab8 and Rab11, which are key regulators of membrane trafficking from the trans-Golgi network and recycling endosome to the plasma membrane. Rab11 and Rab8 coordinate their actions via Rabin8, the guanine nucleotide exchange factor of Rab8. A cascade of protein-protein interactions involving the Rabs and the exocyst complex couples the generation of secretory vesicles at donor compartments to their docking and fusion at the plasma membrane. Here, we discuss recent work implicating Rab proteins and the exocyst in primary ciliogenesis and epithelial lumenogenesis. In addition, we discuss early work in the budding yeast Saccharomyces cerevisiae, which provided initial insight into the molecular mechanisms of polarized exocytosis.
PMCID: PMC3128673  PMID: 21550243
6.  Transgene Rescue Identifies an Essential Function for Drosophila β Spectrin in the Nervous System and a Selective Requirement for Ankyrin-2–binding Activity 
Molecular Biology of the Cell  2010;21(16):2860-2868.
The Gal4-UAS system was used to overexpress or knock down β spectrin with dsRNA in a variety of Drosophila tissues. Unexpectedly, overexpression in most tissues tested was lethal, whereas knockdown failed to produce a detectable phenotype in the same tissues. The lethality of a β spectrin mutation was rescued by expression of β spectrin in neurons.
The protein spectrin is ubiquitous in animal cells and is believed to play important roles in cell shape and membrane stability, cell polarity, and endomembrane traffic. Experiments here were undertaken to identify sites of essential β spectrin function in Drosophila and to determine whether spectrin and ankyrin function are strictly linked to one another. The Gal4-UAS system was used to drive tissue-specific overexpression of a β spectrin transgene or to knock down β spectrin expression with dsRNA. The results show that 1) overexpression of β spectrin in most of the cell types studied was lethal; 2) knockdown of β spectrin in most tissues had no detectable effect on growth or viability of the organism; and 3) nervous system-specific expression of a UAS-β spectrin transgene was sufficient to overcome the lethality of a loss-of-function β spectrin mutation. Thus β spectrin expression in other cells was not required for development of fertile adult males, although females lacking nonneuronal spectrin were sterile. Previous data indicated that binding of the DAnk1 isoform of ankyrin to spectrin was partially dispensable for viability. Domain swap experiments here uncovered a different requirement for neuronal DAnk2 binding to spectrin and establish that DAnk2-binding is critical for β spectrin function in vivo.
PMCID: PMC2921109  PMID: 20573981
7.  The Drosophila Anion Exchanger (DAE) lacks a detectable interaction with the spectrin cytoskeleton 
Current models suggest that the spectrin cytoskeleton stabilizes interacting ion transport proteins at the plasma membrane. The human erythrocyte anion exchanger (AE1) was the first membrane transport protein found to be associated with the spectrin cytoskeleton. Here we evaluated a conserved anion exchanger from Drosophila (DAE) as a marker for studies of the downstream effects of spectrin cytoskeleton mutations.
Sequence comparisons established that DAE belongs to the SLC4A1-3 subfamily of anion exchangers that includes human AE1. Striking sequence conservation was observed in the C-terminal membrane transport domain and parts of the N-terminal cytoplasmic domain, but not in the proposed ankyrin-binding site. Using an antibody raised against DAE and a recombinant transgene expressed in Drosophila S2 cells DAE was shown to be a 136 kd plasma membrane protein. A major site of expression was found in the stomach acid-secreting region of the larval midgut. DAE codistributed with an infolded subcompartment of the basal plasma membrane of interstitial cells. However, spectrin did not codistribute with DAE at this site or in anterior midgut cells that abundantly expressed both spectrin and DAE. Ubiquitous knockdown of DAE with dsRNA eliminated antibody staining and was lethal, indicating that DAE is an essential gene product in Drosophila.
Based on the lack of colocalization and the lack of sequence conservation at the ankyrin-binding site, it appears that the well-characterized interaction between AE1 and the spectrin cytoskeleton in erythrocytes is not conserved in Drosophila. The results establish a pattern in which most of the known interactions between the spectrin cytoskeleton and the plasma membrane in mammals do not appear to be conserved in Drosophila.
PMCID: PMC2901199  PMID: 20573195
8.  Spectrin functions upstream of ankyrin in a spectrin cytoskeleton assembly pathway 
The Journal of Cell Biology  2006;175(2):325-335.
Prevailing models place spectrin downstream of ankyrin in a pathway of assembly and function in polarized cells. We used a transgene rescue strategy in Drosophila melanogaster to test contributions of four specific functional sites in β spectrin to its assembly and function. (1) Removal of the pleckstrin homology domain blocked polarized spectrin assembly in midgut epithelial cells and was usually lethal. (2) A point mutation in the tetramer formation site, modeled after a hereditary elliptocytosis mutation in human erythrocyte spectrin, had no detectable effect on function. (3) Replacement of repetitive segments 4–11 of β spectrin with repeats 2–9 of α spectrin abolished function but did not prevent polarized assembly. (4) Removal of the putative ankyrin-binding site had an unexpectedly mild phenotype with no detectable effect on spectrin targeting to the plasma membrane. The results suggest an alternate pathway in which spectrin directs ankyrin assembly and in which some important functions of spectrin are independent of ankyrin.
PMCID: PMC2064573  PMID: 17060500

Results 1-8 (8)