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Mathurin P, Deng QG, Keshavarzian A, Choudhary S, Holmes EW, Tsukamoto H. Exacerbation of alcoholic liver injury by enteral endotoxin in rats. Hepatology 2000; 32:1008-17. [PMID: 11050051 DOI: 10.1053/jhep.2000.19621] [Citation(s) in RCA: 232] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Increased gut permeability (leaky gut) and endotoxin-mediated Kupffer cell activation are proposed as the mechanisms of alcoholic liver injury. Although ethanol feeding is shown to sensitize the liver for injury induced by parental administration of lipopolysaccharide (LPS), how enteral LPS loading affects alcoholic liver injury is yet to be tested. The present study provides direct evidence for enhanced entrance to portal circulation of LPS enterally administered to the intragastric ethanol infusion model. Portal and systemic blood endotoxin levels increased to 43.0 +/- 4.1 and 6.2 +/- 4.3 pg/mL at 2 hours following enteral LPS administration (5 mg/kg) in alcohol-fed animals, while no such increases were observed in pair-fed controls. However, endotoxin levels in systemic blood of alcohol-fed rats were reduced to 0 to 1. 5 pg/mL 16 hours after LPS administration. Weekly enteral administration of LPS to the model for 9 weeks exacerbated an increase in plasma alanine transaminase (ALT) levels (227 +/- 75 vs. 140 +/- 70; P <.01), mononuclear infiltration (25 +/- 22 vs. 6.4 +/- 4.4/10 mm(2); P =.02), sinusoidal congestion, and spotty necrosis, and induced diffuse coagulative necrosis and centrilobular fibrosis in some animals. Reverse-transcription polymerase chain reaction (RT-PCR) analysis confirmed the LPS effect at the tissue level by demonstrating accentuated induction of tumor necrosis factor alpha (TNF-alpha) and Cox-2 mRNA. In conclusion, enteral LPS administration potentiates alcoholic liver necrosis, inflammation, and fibrosis despite efficient endotoxin clearance by the liver and mild systemic endotoxemia that occurs episodically following enteral LPS challenge.
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Dubey JP, Velmurugan GV, Rajendran C, Yabsley MJ, Thomas NJ, Beckmen KB, Sinnett D, Ruid D, Hart J, Fair PA, McFee WE, Shearn-Bochsler V, Kwok OCH, Ferreira LR, Choudhary S, Faria EB, Zhou H, Felix TA, Su C. Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type. Int J Parasitol 2011; 41:1139-47. [PMID: 21802422 DOI: 10.1016/j.ijpara.2011.06.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 10/17/2022]
Abstract
Little is known of the genetic diversity of Toxoplasma gondii circulating in wildlife. In the present study wild animals, from the USA were examined for T. gondii infection. Tissues of naturally exposed animals were bioassayed in mice for isolation of viable parasites. Viable T. gondii was isolated from 31 animals including, to our knowledge for the first time, from a bald eagle (Haliaeetus leucocephalus), five gray wolves (Canis lupus), a woodrat (Neotoma micropus), and five Arctic foxes (Alopex lagopus). Additionally, 66 T. gondii isolates obtained previously, but not genetically characterised, were revived in mice. Toxoplasma gondii DNA isolated from these 97 samples (31+66) was characterised using 11 PCR-restriction fragment length polymorphism (RFLP) markers (SAG1, 5'- and 3'-SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). A total of 95 isolates were successfully genotyped. In addition to clonal Types II, and III, 12 different genotypes were found. These genotype data were combined with 74 T. gondii isolates previously characterised from wildlife from North America and a composite data set of 169 isolates comprised 22 genotypes, including clonal Types II, III and 20 atypical genotypes. Phylogenetic network analysis showed limited diversity with dominance of a recently designated fourth clonal type (Type 12) in North America, followed by the Type II and III lineages. These three major lineages together accounted for 85% of strains in North America. The Type 12 lineage includes previously identified Type A and X strains from sea otters. This study revealed that the Type 12 lineage accounts for 46.7% (79/169) of isolates and is dominant in wildlife of North America. No clonal Type I strain was identified among these wildlife isolates. These results suggest that T. gondii strains in wildlife from North America have limited diversity, with the occurrence of only a few major clonal types.
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Choudhary S, Rajesh A, Mayer NJ, Mulcahy KA, Haroon A. Renal oncocytoma: CT features cannot reliably distinguish oncocytoma from other renal neoplasms. Clin Radiol 2009; 64:517-22. [PMID: 19348848 DOI: 10.1016/j.crad.2008.12.011] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 12/04/2008] [Accepted: 12/15/2008] [Indexed: 12/22/2022]
Abstract
AIM To retrospectively review the computed tomography (CT) imaging features of a series of histologically confirmed renal oncocytomas and to determine whether imaging features are predictive of this subtype of benign renal epithelial tumour. MATERIALS AND METHODS From May 2001 to October 2007, 21 patients with 28 renal masses, confirmed as renal oncocytoma on histological examination of the resection specimen, were identified from the pathology database at our institution. The preoperative imaging findings were retrospectively analysed to determine characteristic features, if any, to predict this rare subtype of benign renal tumour. RESULTS There were 11 female and 10 male patients and the age at presentation ranged from 40-80 years (mean age 65.9 years). The size of the masses ranged from 1.2-12 cm in diameter (mean diameter 4.9 cm). All masses showed contrast enhancement. In 18 (64.3%) lesions the enhancement of the tumour was isodense to renal cortex. Ten (35.7%) lesions were hypodense to renal cortex. In three (10.7%) lesions, a well-defined stellate central scar was seen at CT and confirmed pathologically. In two (7.1%) lesions, a central scar was identified pathologically, but not seen on CT. The size of the central scars ranged from 10-29 mm diameter on CT. Twenty-two (78.6%) lesions did not demonstrate a scar on CT or pathologically. None of the patients had regional lymphadenopathy or distant metastasis. CONCLUSION Renal oncocytoma is typically described as being hypervascular and homogeneous, with a characteristic central stellate scar on CT. The present study demonstrates that these imaging features are found in only a small proportion of these tumours. Therefore, imaging characteristics alone are unreliable when differentiating between oncocytoma and renal cell carcinoma, and histopathological diagnosis remains the reference standard.
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Journal Article |
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Epstein DM, Choudhary S, Churchill MR, Keil KM, Eliseev AV, Morrow JR. Chloroform-soluble schiff-base Zn(II) or Cd(II) complexes from a dynamic combinatorial library. Inorg Chem 2001; 40:1591-6. [PMID: 11261969 DOI: 10.1021/ic000938t] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A dynamic combinatorial library of metal ion Schiff-base complexes have been studied for the extraction of Zn(II) or Cd(II) from aqueous solution into chloroform. Library components consist of different aminophenols and 2-pyridinecarboxaldehyde. Extraction of both Zn(II) and Cd(II) into chloroform was observed from aqueous solutions containing 0.0500 mM M(NO3)2, 0.100 M aminophenol, 0.100 M 2-pyridinecarboxaldehyde, 0.100 M NaCl, and 5.00 mM buffer at pH 8.5. Extraction was dependent on pH but not on counterions including Cl-, Br-, or NO3-. Studies showed that equilibrium was attained between the Schiff-base complexes across the two-phase chloroform-water system after 24 h of stirring. Analysis of the extracted species by use of 1H NMR spectroscopy and mass spectrometry as well as solubility studies on characterized complexes suggested that the major extracted species is the neutral bis-Schiff-base metal ion complex. In libraries containing mixtures of two different aminophenols and 2-pyridinecarboxaldehyde, an enhanced extent of extraction of Zn(II) into chloroform is observed. Studies suggest that a Zn(II) complex, which is likely the mixed Schiff-base complex, has superior extraction properties compared to simple libraries with a single aminophenol component. The structures of two bis-Schiff-base complexes of Zn(II) and one of Cd(II) have been determined by X-ray crystallography. The geometries of the two Zn(II) complexes, which differ only by a methyl substituent on the Schiff-base ligand, are markedly different, supporting the use of combinatorial methods in coordination chemistry. Zn(SB14)2 crystallized as the sesquihydrate (C24H18N4O2Zn.1.5 H2O) in the space group C2/c, with cell dimensions a = 23.219(15) A, b = 11.299(7) A, c = 16.822(11) A, beta = 102.91(5) degrees, V = 4302(5) A3, and Z = 8. Zn(SB15)2 crystallized as a 1:1 methanol solvate (C26H22N4O2Zn.CH3OH) in the space group P2(1)/c with cell dimensions a = 13.981(5) A, b = 7.978(3) A, c = 22.568(8) A, beta = 104.53(3) degrees, V = 2436.8(15) A3, and Z = 4. Cd(SB14)2 crystallized as a 1:1 ethanol solvate (C24H18N4O2Cd.CH3CH2OH) in the space group R3 with unit cell dimensions of a = 36.423(2) A, c = 9.2930(10) A, V = 10678(2) A3, and Z = 18.
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Choudhary S, Gupta L, Rani S, Dave K, Gupta U. Impact of Dendrimers on Solubility of Hydrophobic Drug Molecules. Front Pharmacol 2017; 8:261. [PMID: 28559844 PMCID: PMC5432624 DOI: 10.3389/fphar.2017.00261] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 04/26/2017] [Indexed: 12/31/2022] Open
Abstract
Adequate aqueous solubility has been one of the desired properties while selecting drug molecules and other bio-actives for product development. Often solubility of a drug determines its pharmaceutical and therapeutic performance. Majority of newly synthesized drug molecules fail or are rejected during the early phases of drug discovery and development due to their limited solubility. Sufficient permeability, aqueous solubility and physicochemical stability of the drug are important for achieving adequate bioavailability and therapeutic outcome. A number of different approaches including co-solvency, micellar solubilization, micronization, pH adjustment, chemical modification, and solid dispersion have been explored toward improving the solubility of various poorly aqueous-soluble drugs. Dendrimers, a new class of polymers, possess great potential for drug solubility improvement, by virtue of their unique properties. These hyper-branched, mono-dispersed molecules have the distinct ability to bind the drug molecules on periphery as well as to encapsulate these molecules within the dendritic structure. There are numerous reported studies which have successfully used dendrimers to enhance the solubilization of poorly soluble drugs. These promising outcomes have encouraged the researchers to design, synthesize, and evaluate various dendritic polymers for their use in drug delivery and product development. This review will discuss the aspects and role of dendrimers in the solubility enhancement of poorly soluble drugs. The review will also highlight the important and relevant properties of dendrimers which contribute toward drug solubilization. Finally, hydrophobic drugs which have been explored for dendrimer assisted solubilization, and the current marketing status of dendrimers will be discussed.
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Review |
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Banan A, Choudhary S, Zhang Y, Fields JZ, Keshavarzian A. Oxidant-induced intestinal barrier disruption and its prevention by growth factors in a human colonic cell line: role of the microtubule cytoskeleton. Free Radic Biol Med 2000; 28:727-38. [PMID: 10754268 DOI: 10.1016/s0891-5849(00)00160-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Reactive oxygen metabolites (ROM) are increased in the inflamed mucosa of inflammatory bowel disease (IBD) and may contribute to loss of intestinal barrier function in this disorder. Growth factors (GF) are protective. But the mechanisms of disruption and protection remain elusive. In the present investigation, we hypothesized that the microtubules (a critical cytoskeletal element) play a key role in the molecular mechanism of intestinal barrier dysfunction induced by ROM and in GF-mediated protection. Utilizing monolayers of a human colonic cell line (Caco-2), we evaluated the effects of ROM (H(2)O(2) or HOCl), in the presence or absence of GF (epidermal growth factor [EGF]; transforming growth factor-alpha [TGF-alpha]), on intestinal barrier function, tubulin (microtubule structural protein), and microtubule stability. Monolayers were also processed for two highly sensitive western immunoblots: fractionated polymerized tubulin (S2; an index of stability); monomeric tubulin (S1; an index of disruption) to detect the oxidation and disassembly/assembly of tubulin. ROM exposure led to a significant increase in the oxidation of tubulin, decrease in the stable S2 polymerized tubulin, and increase in the unstable S1 monomeric tubulin. In concert, each ROM in a dose dependent manner damaged the microtubule cytoskeleton and disrupted barrier function. GF pretreatment not only increased the S2 stable tubulin and decreased tubulin oxidation but also, concomitantly, prevented the disruption of microtubules and loss of barrier function in monolayers exposed to ROM. Antibody against the GF-receptor and inhibitors of GF-receptor tyrosine kinase abolished GF protection, indicating the involvement of epidermal growth factor receptor (EGFR) signaling pathway. As predicted, colchicine, an inhibitor of microtubule assembly, caused barrier dysfunction and prevented GF protection whereas taxol, a microtubule-stabilizing agent, mimicked the protective effects of GF. Thus, organization and stability of the microtubule cytoskeleton appears to be critical to both oxidant-induced mucosal barrier dysfunction and protection of intestinal barrier mediated by GF. Therefore, microtubules may be useful targets for development of drugs for the treatment of IBD.
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Kennedy M, Bruninga K, Mutlu EA, Losurdo J, Choudhary S, Keshavarzian A. Successful and sustained treatment of chronic radiation proctitis with antioxidant vitamins E and C. Am J Gastroenterol 2001; 96:1080-4. [PMID: 11316150 DOI: 10.1111/j.1572-0241.2001.03742.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Chronic radiation proctitis, a common sequelae of pelvic radiation, is characterized by obliteration of the submucosal vasculature with subsequent ischemia and reperfusion injury. Oxidative stress is thought to be a major mechanism in radiation proctitis. Therefore, antioxidants (vitamins E and C) may be beneficial. METHODS Twenty consecutive symptomatic outpatients with endoscopically documented radiation proctitis seen in a single gastroenterology clinic were given a combination of vitamin E (400 IU tid) and vitamin C (500 mg tid). Previous radiation therapy was given for prostatic (n = 10) or gynecological (n = 10) malignancies. These patients presented with one or more of the following symptoms: rectal bleeding, rectal pain, diarrhea, or fecal urgency. Using a questionnaire, these symptoms were rated by the patients in terms of their severity (grade 0-4) and frequency (grade 0-4) before and after treatment with vitamins E and C. A symptom index was calculated by the addition of the severity and frequency scores (8 = most symptomatic). The lifestyle impact of the symptoms was also assessed by questionnaire grading from 0 (no effect on daily activity) to 4 (afraid to leave home). Among these 20 patients, 10 patients who received vitamins E and C for 1 yr were assessed again to determine whether their initial responses were sustained. RESULTS There was a significant (p < 0.05; Wilcoxon rank) improvement in the symptom index (before treatment vs after treatment with vitamins E and C) for bleeding (median score: 4 vs 0), diarrhea (median score: 5 vs 0), and urgency (median score: 6 vs 3). Patients with rectal pain did not improve significantly. Bleeding resolved in four of 11 patients, diarrhea resolved in eight of 16 patients, fecal urgency resolved in three of 16 patients, and rectal pain resolved in two of six patients. Lifestyle improved in 13 patients, including seven patients who reported a return to normal. Two of the patients with no improvement in their daily symptoms also had radiation ileitis. All 10 patients who underwent a second follow-up interview reported sustained improvement in their symptoms 1 yr later. CONCLUSION A substantial number of patients with radiation proctitis seem to benefit from antioxidant therapy. A double-blind placebo-controlled trial is needed to confirm this open-labeled pilot study.
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Clinical Trial |
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Choudhary S, Xiao T, Srivastava S, Zhang W, Chan LL, Vergara LA, Van Kuijk FJGM, Ansari NH. Toxicity and detoxification of lipid-derived aldehydes in cultured retinal pigmented epithelial cells. Toxicol Appl Pharmacol 2005; 204:122-34. [PMID: 15808518 DOI: 10.1016/j.taap.2004.08.023] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 08/30/2004] [Indexed: 11/22/2022]
Abstract
Age-related macular degeneration (ARMD) is the leading cause of blindness in the developed world and yet its pathogenesis remains poorly understood. Retina has high levels of polyunsaturated fatty acids (PUFAs) and functions under conditions of oxidative stress. To investigate whether peroxidative products of PUFAs induce apoptosis in retinal pigmented epithelial (RPE) cells and possibly contribute to ARMD, human retinal pigmented epithelial cells (ARPE-19) were exposed to micromolar concentrations of H2O2, 4-hydroxynonenal (HNE) and 4-hydroxyhexenal (HHE). A concentration- and time-dependent increase in H2O2-, HNE-, and HHE-induced apoptosis was observed when monitored by quantifying DNA fragmentation as determined by ELISA, flow cytometry, and Hoechst staining. The broad-spectrum inhibitor of apoptosis Z-VAD inhibited apoptosis. Treatment of RPE cells with a thionein peptide prior to exposure to H2O2 or HNE reduced the formation of protein-HNE adducts as well as alteration in mitochondrial membrane potential and apoptosis. Using 3H-HNE, various metabolic pathways to detoxify HNE by ARPE-19 cells were studied. The metabolites were separated by HPLC and characterized by ElectroSpray Ionization-Mass Spectrometry (ESI-MS) and gas chromatography-MS. Three main metabolic routes of HNE detoxification were detected: (1) conjugation with glutathione (GSH) to form GS-HNE, catalyzed by glutathione-S-transferase (GST), (2) reduction of GS-HNE catalyzed by aldose reductase, and (3) oxidation of HNE catalyzed by aldehyde dehydrogenase (ALDH). Preventing HNE formation by a combined strategy of antioxidants, scavenging HNE by thionein peptide, and inhibiting apoptosis by caspase inhibitors may offer a potential therapy to limit retinal degeneration in ARMD.
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Banan A, Zhang LJ, Shaikh M, Fields JZ, Choudhary S, Forsyth CB, Farhadi A, Keshavarzian A. theta Isoform of protein kinase C alters barrier function in intestinal epithelium through modulation of distinct claudin isotypes: a novel mechanism for regulation of permeability. J Pharmacol Exp Ther 2005. [PMID: 15900076 DOI: 10.1124/jpet.105.083428] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Using monolayers of intestinal Caco-2 cells, we discovered that the isoform of protein kinase C (PKC), a member of the "novel" subfamily of PKC isoforms, is required for monolayer barrier function. However, the mechanisms underlying this novel effect remain largely unknown. Here, we sought to determine whether the mechanism by which PKC- disrupts monolayer permeability and dynamics in intestinal epithelium involves PKC--induced alterations in claudin isotypes. We used cell clones that we recently developed, clones that were transfected with varying levels of plasmid to either stably suppress endogenous PKC- activity (antisense, dominant-negative constructs) or to ectopically express PKC- activity (sense constructs). We then determined barrier function, claudin isotype integrity, PKC- subcellular activity, claudin isotype subcellular pools, and claudin phosphorylation. Antisense transfection to underexpress the PKC- led to monolayer instability as shown by reduced 1) endogenous PKC- activity, 2) claudin isotypes in the membrane and cytoskeletal pools ( downward arrowclaud-1, downward arrowclaud-4 assembly), 3) claudin isotype phosphorylation ( downward arrow phospho-serine, downward arrow phospho-threonine), 4) architectural stability of the claudin-1 and claudin-4 rings, and 5) monolayer barrier function. In these antisense clones, PKC- activity was also substantially reduced in the membrane and cytoskeletal cell fractions. In wild-type (WT) cells, PKC- (82 kDa) was both constitutively active and coassociated with claudin-1 (22 kDa) and claudin-4 (25 kDa), forming endogenous PKC-/claudin complexes. In a second series of studies, dominant-negative inhibition of the endogenous PKC- caused similar destabilizing effects on monolayer barrier dynamics, including claudin-1 and -4 hypophosphorylation, disassembly, and architectural instability as well as monolayer disruption. In a third series of studies, sense overexpression of the PKC- caused not only a mostly cytosolic distribution of this isoform (i.e., <12% in the membrane + cytoskeletal fractions, indicating PKC- inactivity) but also led to disruption of claudin assembly and barrier function of the monolayer. The conclusions of this study are that PKC- activity is required for normal claudin assembly and the integrity of the intestinal epithelial barrier. These effects of PKC- are mediated at the molecular level by changes in phosphorylation, membrane assembly, and/or organization of the subunit components of two barrier function proteins: claudin-1 and claudin-4 isotypes. The ability of PKC- to alter the dynamics of permeability protein claudins is a new function not previously ascribed to the novel subfamily of PKC isoforms.
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Research Support, U.S. Gov't, P.H.S. |
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Kini A, Marmur JD, Duvvuri S, Dangas G, Choudhary S, Sharma SK. Rotational atherectomy: improved procedural outcome with evolution of technique and equipment. Single-center results of first 1,000 patients. Catheter Cardiovasc Interv 1999; 46:305-11. [PMID: 10348127 DOI: 10.1002/(sici)1522-726x(199903)46:3<305::aid-ccd9>3.0.co;2-u] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present our single-center experience of rotational atherectomy (RA) in the first 1,000 consecutive patients divided arbitrarily into three different time periods corresponding to significant changes in technique or equipment for RA. Period I (August 1994 to April 1995; 172 cases) is characterized by early experience, longer ablation, and frequent use of intra-aortic balloon pump; period II (May 1995 to January 1996; 254 cases) is characterized by short ablation runs (20-30 sec) and use of rotaflush; period III (February 1996 to February 1997; 574 cases) is characterized by ReoPro use, neosynephrine boluses to avoid hypotension, and rota floppy wire and flexible shaft burrs. The procedural success rate has improved and complication rates have progressively declined over these three time periods. The incidence of lesion complexity (long and type C lesions) and patients with unstable rest angina have increased over these time periods of RA. Therefore, modification in procedural techniques and equipment over time have made RA a safe technique despite its use in very complex lesion subsets.
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Choudhary S, Zhang W, Zhou F, Campbell GA, Chan LL, Thompson EB, Ansari NH. Cellular lipid peroxidation end-products induce apoptosis in human lens epithelial cells. Free Radic Biol Med 2002; 32:360-9. [PMID: 11841926 DOI: 10.1016/s0891-5849(01)00810-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Hydrogen peroxide (H(2)O(2)), an oxidant present in high concentrations in the aqueous humor of the elderly eyes, is known to impart toxicity to the lens---apoptosis being one of the toxic events. Since H(2)O(2) causes lipid peroxidation leading to the formation of reactive end-products, it is important to investigate whether the end-products of lipid peroxidation are involved in the oxidation-induced apoptosis in the lens. 4-Hydroxynonenal (HNE), a major cytotoxic end product of lipid peroxidation, has been shown to mediate oxidative stress-induced cell death in many cell types. It has been shown that HNE is cataractogenic in micromolar concentrations in vitro, however, the underlying mechanism is not yet clearly understood. In the present study we have demonstrated that H(2)O(2) and the lipid derived aldehydes, HNE and 4-hydroxyhexenal (HHE), can induce dose- and time-dependent loss of cell viability and a simultaneous increase in apoptosis involving activation of caspases such as caspase-1, -2, -3, and -8 in the cultured human lens epithelial cells. Interestingly, we observed that Z-VAD, a broad range inhibitor of caspases, conferred protection against H(2)O(2)- and HNE-induced apoptosis, suggesting the involvement of caspases in this apoptotic system. Using the cationic dye JC-1, early apoptotic changes were assessed following 5 h of HNE and H(2)O(2) insult. Though HNE exposure resulted in approximately 50% cells to undergo early apoptotic changes, no such changes were observed in H(2)O(2) treated cells during this period. Furthermore, apoptosis, as determined by quantifying the DNA fragmentation, was apparent at a much earlier time period by HNE as opposed to H(2)O(2). Taken together, the results demonstrate the apoptotic potential of the lipid peroxidation end-products and suggest that H(2)O(2)-induced apoptosis may be mediated by these end-products in the lens epithelium.
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Gupta AK, Blondel D, Choudhary S, Banerjee AK. The phosphoprotein of rabies virus is phosphorylated by a unique cellular protein kinase and specific isomers of protein kinase C. J Virol 2000; 74:91-8. [PMID: 10590095 PMCID: PMC111517 DOI: 10.1128/jvi.74.1.91-98.2000] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The phosphoprotein (P) gene of rabies virus (CVS strain) was cloned and expressed in bacteria. The purified protein was used as the substrate for phosphorylation by the protein kinase(s) present in cell extract prepared from rat brain. Two distinct types of protein kinases, staurosporin sensitive and heparin sensitive, were found to phosphorylate the P protein in vitro by the cell extract. Interestingly, the heparin-sensitive kinase was not the ubiquitous casein kinase II present in a variety of cell types. Further purification of the cell fractions revealed that the protein kinase C (PKC) isomers constitute the staurosporin-sensitive kinases alpha, beta, gamma, and zeta, with the PKCgamma isomer being the most effective in phosphorylating the P protein. A unique heparin-sensitive kinase was characterized as a 71-kDa protein with biochemical properties not demonstrated by any known protein kinases stored in the protein data bank. This protein kinase, designated RVPK (rabies virus protein kinase), phosphorylates P protein (36 kDa) and alters its mobility in gel to migrate at 40 kDa. In contrast, the PKC isoforms do not change the mobility of unphosphorylated P protein. RVPK appears to be packaged in the purified virions, to display biochemical characteristics similar to those of the cell-purified RVPK, and to similarly alter the mobility of endogenous P protein upon phosphorylation. By site-directed mutagenesis, the sites of phosphorylation of RVPK were mapped at S(63) and S(64), whereas PKC isomers phosphorylated at S(162), S(210), and S(271). Involvement of a unique protein kinase in phosphorylating rabies virus P protein indicates its important role in the structure and function of the protein and consequently in the life cycle of the virus.
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research-article |
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Sengwa RJ, Choudhary S, Sankhla S. Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone)−ethylene glycol blends. EXPRESS POLYM LETT 2008. [DOI: 10.3144/expresspolymlett.2008.93] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Choudhary S, Keshavarzian A, Yong S, Wade M, Bocckino S, Day BJ, Banan A. Novel antioxidants zolimid and AEOL11201 ameliorate colitis in rats. Dig Dis Sci 2001; 46:2222-30. [PMID: 11680601 DOI: 10.1023/a:1011975218006] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mechanism of tissue damage in ulcerative colitis (UC) is unknown. However, recent evidence suggests that reactive oxygen species (ROS) are critical mediators of inflammation, and tissue damage in UC and antioxidants could be beneficial in the treatment of UC. Our aim was to evaluate the effects of two new antioxidants, Zolimid and AEOL11201 on experimental colitis. Antioxidants or vehicle were given to rats for five days after induction of colitis by intrarectal administration of 4% acetic acid. Severity of colitis was assessed on day 5. Zolimid and AEOL11201 significantly improved acetic acid-induced colitis. Both Zolimid and AEOL11201 significantly decreased the severity of diarrhea, and severity of macroscopic and histological changes in the colon. Both agents also significantly decreased colonic MPO levels. In conclusion, Zolimid and AEOL11201 are effective antiinflammatory agents in an animal model of colitis. Further studies are needed to evaluate their beneficial therapeutic effects in patients with UC.
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Xiao T, Choudhary S, Zhang W, Ansari NH, Salahudeen A. Possible involvement of oxidative stress in cisplatin-induced apoptosis in LLC-PK1 cells. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2003; 66:469-479. [PMID: 12712633 DOI: 10.1080/15287390306449] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Use of cisplatin, a chemotherapeutic agent, is associated with toxicity as a significant number of patients develop a decline in renal function. The mechanisms by which cisplatin produces renal injury are not well understood. It has been suggested that free radical-catalyzed lipid peroxidation can induce apoptosis or necrosis leading to renal injury. This study examined whether low concentrations of cisplatin induce apoptosis in LLC-PK1 cells and whether caspases 1, 2, 3, 8, and 9 are activated during this event. Our results show a dose- and time-dependent induction of apoptosis by micromolar concentrations of cisplatin. Expression of oncogenes c-myc and p53 was induced, and except for caspase 1, all the other caspases tested were activated. Z-VAD, the broad-spectrum inhibitor of caspases, prevented caspase activation and apoptosis, but not c-myc and p53 induction. On the other hand, N-acetylcysteine prevented cisplatin-induced apoptosis as well as c-myc induction but not p53 induction. The antioxidant trolox also prevented cisplatin-induced apoptosis. The results suggest that antioxidants and caspase inhibitors may alleviate cisplatin-associated nephrotoxicity.
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Dubey J, Hill D, Rozeboom D, Rajendran C, Choudhary S, Ferreira L, Kwok O, Su C. High prevalence and genotypes of Toxoplasma gondii isolated from organic pigs in northern USA. Vet Parasitol 2012; 188:14-8. [DOI: 10.1016/j.vetpar.2012.03.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 10/28/2022]
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Abstract
OBJECTIVE Delusional parasitosis is a form of monohypochondriacal psychosis, a condition sometimes encountered in psychiatric or primary care practice. The outcome of this condition is not well known. METHOD In the present study, a series of fifty-two consecutive cases of delusional parasitosis is reported. RESULTS A majority of cases (92%) had insidious onset. The duration of symptoms in all but two cases was six months or more. Twenty-six cases presented with a delusion of infestation by insects over the body and twenty-three cases with a delusion of insects crawling over the scalp. Three cases had associated diabetes mellitus, five cases had leprosy, five cases dementia, four cases had depression, and three cases presented with trichotillomania. Pimozide was used in forty-six cases, amitriptyline and fluoxetine in three cases each. Twenty-eight cases (54%) showed complete remission while receiving pharmacotherapy, eighteen cases showed partial improvement, and six cases did not respond to treatment. CONCLUSION Further studies are warranted to study the treatment and outcome of this important psychiatric disorder.
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Dubey JP, Van Why K, Verma SK, Choudhary S, Kwok OCH, Khan A, Behinke MS, Sibley LD, Ferreira LR, Oliveira S, Weaver M, Stewart R, Su C. Genotyping Toxoplasma gondii from wildlife in Pennsylvania and identification of natural recombinants virulent to mice. Vet Parasitol 2013; 200:74-84. [PMID: 24332401 DOI: 10.1016/j.vetpar.2013.11.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/30/2013] [Accepted: 11/01/2013] [Indexed: 11/24/2022]
Abstract
Recent studies indicated the predominance of Toxoplasma gondii haplogroup 12 in wildlife in the USA. However, still little is known of the genetic diversity of this parasite circulating in wildlife. In the present study, we tested coyotes (Canis latrans), red foxes (Vulpes vulpes), white-tailed deer (Odocoileus virginianus), and geese (Branta canadensis) from the state of Pennsylvania for T. gondii infection. Antibodies to T. gondii were found in 160 of 367 animals, including 92 (34.5%) of 266 coyotes, 49 (62.0%) of 79 white-tailed deer, 17 (85.0%) of 20 red fox, and two of two Canada geese tested by the modified agglutination test (cut off titer 1:25). Tissues from 105 seropositive animals were bioassayed in mice, and viable T. gondii was isolated from 29 animals, including 10 of 53 coyotes, 11 of 16 foxes, 7 of 49 deer, and one of one goose. DNA isolated from culture-derived tachyzoites of these isolates was characterized initially using multilocus PCR-RFLP markers. Nine genotypes were revealed, including ToxoDB PCR-RFLP #1 (4 isolates), #2 (2 isolates), #3 (4 isolates), #4 (6 isolates), #5 (4 isolates), #54 (1 isolate), #141 (1 isolate), #143 (1 isolate), and #216 (6 isolates), indicating high genetic diversity of T. gondii in wildlife in Pennsylvania. Pathogenicity of six T. gondii isolates (5 of #216 and #141) was determined in outbred Swiss Webster mice. Three of #216 and the #141 isolates were acute virulent to mice, and the other 2 #216 isolates were intermediate virulent. To determine the extent of genetic variation of these as well as a few recently reported virulent isolates from wildlife in North America, intron sequences were generated. Analysis of intron sequences and PCR-RFLP genotyping results indicated that the #216 isolates are likely derived from recombination of the clonal type I and III lineages. To determine if T. gondii virulence can be predicted by typing, we genotyped a collection of strains using PCR-RFLP markers for polymorphic genes ROP5, ROP16, ROP18 and GRA15, which are known to interact with host immune response. The results showed that there is an association of genotypes of ROP5 and ROP18 with mouse-virulence, however, additional gene(s) may also contribute to virulence in distinct T. gondii genotypes.
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Research Support, N.I.H., Extramural |
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Choudhary S, Singh P, Sundar E, Kumar S, Sahai A. A comparison of sonourethrography and retrograde urethrography in evaluation of anterior urethral strictures. Clin Radiol 2004; 59:736-42. [PMID: 15262549 DOI: 10.1016/j.crad.2004.01.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Revised: 01/21/2004] [Accepted: 01/27/2004] [Indexed: 10/26/2022]
Abstract
AIM This prospective study was undertaken to evaluate the abnormalities of the male anterior urethra using high-resolution ultrasound (sonourethrography) and to compare the efficacy with that of retrograde urethrography (RGU) using operative findings as the gold standard. MATERIALS AND METHODS Seventy patients with symptoms of lower urinary tract obstruction underwent RGU followed by sonourethrography. The sonologist was blinded to the findings of RGU. The parameters studied were compared with the intra-operative findings as gold standard, and the sensitivity, specificity and overall accuracy for the procedures were calculated. Chi-square test and kappa statistics were used where appropriate. RESULTS All patients found to have urethral stricture disease by RGU were also detected by sonourethrography and confirmed intra-operatively. In the estimation of stricture length, RGU showed a lower sensitivity (60-80%) for lengths 1-4 cm, compared with sonourethrography (73.3-100%). Spongiofibrosis was detected by sonourethrography with a sensitivity of 77.3-83.3%. All the false tracts and calculi detected at sonourethrography were confirmed at surgery, whereas RGU showed a low sensitivity in their detection. The complications encountered during the procedures were pain, urethral bleeding and contrast intravasation. The frequency of pain during RGU was greater (p < 0.001); however, the difference in frequency of bleeding after the two procedures was not significant (p < 0.5). CONCLUSION RGU and sonourethrography are equally efficacious in detection of anterior urethral strictures. Further characterization of strictures in terms of length, diameter and periurethral pathologies, like spongiofibrosis and false tracts, is done with greater sensitivity using sonourethrography as compared with RGU, with the added benefit of lower incidence of complications.
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Choudhary S, Taams KO. Umbilicosculpture: a concept revisited. BRITISH JOURNAL OF PLASTIC SURGERY 1998; 51:538-41. [PMID: 9924408 DOI: 10.1054/bjps.1998.0051] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
After birth the umbilicus is the only naturally formed visible scar on the body. To reconstruct a neo-umbilicus following abdominoplasty various local interposition flaps have been described to circumvent a circular scar contracture and to recreate a superior hood. The additional scarring with these techniques can give an operated look to the neo-umbilicus. The importance of gravity in the formation of a superior hood is highlighted and the issue of circular scar contractures is addressed. Emphasis is placed on sculpturing the peri-umbilical fat to enhance contour and on placing the circular scar deep in the neo-umbilicus.
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Sengwa RJ, Choudhary S. Investigation of correlation between dielectric parameters and nanostructures in aqueous solution grown poly(vinyl alcohol)-montmorillonite clay nanocomposites by dielectric relaxation spectroscopy. EXPRESS POLYM LETT 2010. [DOI: 10.3144/expresspolymlett.2010.70] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Arora A, Kannan S, Gowri S, Choudhary S, Sudarasanan S, Khosla PP. Substance abuse amongst the medical graduate students in a developing country. Indian J Med Res 2017; 143:101-3. [PMID: 26997021 PMCID: PMC4822348 DOI: 10.4103/0971-5916.178617] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background & objectives: Substance abuse is found worldwide including among students. We carried out this study to estimate the prevalence of substance abuse among medical student studying in a medical college in north India. Methods: Using a validated questionnaire a cross-sectional survey was conducted among 230 undergraduate and postgraduate medical students in a private medical college. Results: The prevalence of substance abuse was 20.43 per cent (47/230) among medical students. An increase in substance abuse was observed in the latter years of medical education. A total of 43 of 47 (91.7%) students using these substances were aware of the ill effects. The most common reasons for substance use were relief from psychological stress (34/47, 72.4%) and occasional celebration (34/47, 72.4%). Of the 47 substance users, 28 (59.6%) made past attempts to quit the substance abuse. Interpretation & conclusions: Nearly one-fifth of medical students abuse at least one substance despite knowing the ill effects with the main predisposing factor being the psychological stress.
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Research Support, Non-U.S. Gov't |
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De BP, Hoffman MA, Choudhary S, Huntley CC, Banerjee AK. Role of NH(2)- and COOH-terminal domains of the P protein of human parainfluenza virus type 3 in transcription and replication. J Virol 2000; 74:5886-95. [PMID: 10846069 PMCID: PMC112084 DOI: 10.1128/jvi.74.13.5886-5895.2000] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The phosphoproteins (P proteins) of paramyxoviruses play a central role in transcription and replication of the viruses by forming the RNA polymerase complex L-P and encapsidation complex (N-P) with nucleocapsid protein (N) and binding to N protein-encapsidated genome RNA template (N-RNA template). We have analyzed the human parainfluenza virus type 3 (HPIV3) P protein and deletion mutants thereof in an in vitro transcription and in vivo replication system. The in vitro system utilizes purified N-RNA template and cell extract containing L and P proteins coexpressed via plasmids using a recombinant vaccinia virus expression system. The in vivo system takes advantage of minigenome replication, which measures luciferase reporter gene expression from HPIV3 minigenomes by viral proteins in a recombinant vaccinia virus expression system. These studies revealed that the C-terminal 20-amino-acid region of P is absolutely required for transcription in vitro and luciferase expression in vivo, suggesting its critical role in viral RNA synthesis. The N-terminal 40-amino-acid region, on the other hand, is essential for luciferase expression but dispensable for transcription in vitro. Consistent with these findings, the C-terminal domain is required for binding of P protein to the N-RNA template involved in both transcription and replication, whereas the N-terminal domain is required for the formation of soluble N-P complex involved in encapsidation of nascent RNA chains during replication. Coimmunoprecipitation analysis showed that the P protein forms a stable homooligomer (perhaps a trimer) that is present in L-P and N-P complexes in the higher oligomeric forms (at least a pentamer). Interestingly, coexpression of a large excess of N- or C-terminally deleted P with wild-type P had no effect on minigenome replication in vivo, notwithstanding the formation of heterooligomeric complexes. These data indicate that P protein with a deleted terminal domain can function normally within the P heterooligomeric complex to carry out transcription and replication in vivo.
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Alvarado-Esquivel C, Rajendran C, Ferreira LR, Kwok OCH, Choudhary S, Alvarado-Esquivel D, Rodríguez-Peña S, Villena I, Dubey JP. Prevalence of Toxoplasma gondii Infection in Wild Birds in Durango, Mexico. J Parasitol 2011; 97:809-12. [DOI: 10.1645/ge-2844.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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