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Arroyo S, Boothman BR, Brodie MJ, Duncan JS, Duncan R, Nieto M, Calandre EP, Forcadas I, Crawford PM. A randomised open-label study of tiagabine given two or three times daily in refractory epilepsy. Seizure 2005; 14:81-4. [PMID: 15694559 DOI: 10.1016/j.seizure.2004.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Efficacy and tolerability of tiagabine was evaluated in patients with non-controlled partial seizures in a multicentre, open-label, parallel group study. Tiagabine was administered either two (b.i.d.) or three times daily (t.i.d.) as adjunctive therapy and titrated stepwise to a target of 40 mg/day during a 12-week, fixed-schedule titration period; this was followed by a 12-week flexible continuation period. The primary efficacy endpoint was the proportion of patients completing the fixed-schedule titration period. A total of 243 patients were randomised and received treatment, 123 to b.i.d. and 120 to t.i.d. dosing. Fewer patients in the b.i.d. (76 and 62%) than in the t.i.d. (87 and 72%) group completed the fixed-schedule titration period (OR: 0.562; 95% CI: 0.309-1.008; P=0.0532). The median percentage decrease in all types of seizure (excluding status epilepticus) during the fixed schedule titration period was 33.4% for the b.i.d. and 23.8% for the t.i.d. groups (P=0.9634; Van Elteren's test). The proportion of responders was similar for the b.i.d. and t.i.d. groups. There were no significant differences between dosage regimens in the change in median seizure rates from baseline. Adverse events were more frequent during the titration than the continuation period. Most events were mild and related to the central nervous system. Although their incidence was similar between treatment groups, severity was more frequent in the b.i.d. group. Our results suggest that during titration tiagabine is better tolerated with t.i.d. dosing, but during long-term maintenance, a t.i.d. schedule is as effective and well tolerated as b.i.d.
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Oto M, Conway P, McGonigal A, Russell AJ, Duncan R. Gender differences in psychogenic non-epileptic seizures. Seizure 2005; 14:33-9. [PMID: 15642498 DOI: 10.1016/j.seizure.2004.02.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To determine whether male and female populations of patients with psychogenic non-epileptic seizures (PNES) are similar, in terms of demographic and social factors, aetiological factors, the clinical characteristics of events and path to diagnosis. METHODS Prospective study by semi-structured interview of 160 consecutive patients (117 female and 43 male) with video EEG confirmed diagnosis of PNES + epileptic seizures (ES). RESULTS Most parameters showed no significant differences. Males were, however, more likely to be unemployed (P = 0.028), and females were six times more likely to self-harm (P = 0.050), though the numbers were small in these categories. Men were more likely to attribute their PNES to a predisposing factor for epilepsy (P = 0.001), and women were over eight times more likely to report sexual abuse (P = 0.001). Event semiology was similar, but women were more likely to weep after events (P = 0.017). The carers and family of men with PNES were three times less likely to accept the diagnosis of PNES (P = 0.017). CONCLUSIONS Our samples showed few significant gender differences, suggesting that other male and female populations of patients with PNES are likely to be similar also. Some of the differences we found may give insight into causation of PNES.
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Hawk R, Duncan R, Rose C, Chiu C, Qian L, Mircheff A. Intracellular Traffic of Novel Candidate Autoimmune Dacryoadenitis Antigens. Ocul Surf 2005. [DOI: 10.1016/s1542-0124(12)70435-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Shapshak P, Duncan R, Torres-Munoz JE, Duran EM, Minagar A, Petito CK. Analytic approaches to differential gene expression in AIDS versus control brains. FRONT BIOSCI-LANDMRK 2004; 9:2935-46. [PMID: 15353327 DOI: 10.2741/1449] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously showed that specific strains of human immunodeficiency virus (HIV)-1 infect the brain and contribute to Neuropathology, Cognitive Distress, and Neuropsychiatric Disease. To study further brain disease that results from HIV-1 infection, we commenced analysis of changes in gene expression in brain. We analyzed RNA purified from Frontal Cortex of 5 HIV-1 infected and 4 HIV-1 negative control subjects RNA was amplified and Affymetrix technology was used to analyze gene expression using the 12,585 gene Affymetrix Human Genome U95A chip. The expressed genes showed highly significant Pearsons correlations with each other within the two groups. Expression intensities were transferred to Microsoft Excel and Spotfire was used to analyze the results. Twenty-group K-means cluster analysis was done for HIV+ and HIV- subjects. Genes that were expressed in the same cluster numbers in the two groups were removed from further analysis. Analysis of Gene expression in the top 13 HIV+ clusters showed expression in the 40 gene categories designated in our prior studies. Genes from several categories occurred in more than one K-means cluster. Genes identified in these lists included several genes that have been previously studied: MBP, Myelin-PLP, NMDA receptor, MAG, astrocytic protein, Notch 3, APP, Senescence, proteasome, Ferritin, signaling, cell cycle, iNOS, Chemokine, splicing, synapse, protein tags, and ribosomal proteins. The first (primary significant) axis of both Principal Component Analyses ordered the genes in the same patient groups as the K-means cluster analysis for the respective patient groups. PCA was thus not more informative than K-Means cluster analysis. Ratios of HIV+ to HIV- intensities were calculated for all the averaged gene expression intensities. The ratio range was 0.14 to 9.26. The genes at the extremes (ad extrema) did not correspond to the gene order by K-means clustering (or PCA). The genes in the top 13 K-means clusters showed low-level changes by expression ratio. Genes ad extrema by ratio were in clusters with very large memberships. Mann-Whitney analysis confirmed expression ratio results. Several inferences result from our preliminary study. First, study design will be different in future studies involving additional replicates. Second, ratios inform us of the extent of changes in gene expression quantitatively. Third, Cluster methodology provides us with more subtle information, how bunches (clusters) of genes behave in terms of their centroids (attractors). Fourth, genes that change extensively by ratio tend to be in the larger k-Means clusters. We conclude that ranking gene expression with the use of expression ratio or by K-means clustering, yield different representations of the data.
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Duncan R, Oto M, Russell AJC, Conway P. Pseudosleep events in patients with psychogenic non-epileptic seizures: prevalence and associations. J Neurol Neurosurg Psychiatry 2004; 75:1009-12. [PMID: 15201361 PMCID: PMC1739122 DOI: 10.1136/jnnp.2003.022632] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To determine the prevalence and clinical associations of a history of events during sleep in patients with psychogenic non-epileptic seizures (PNES, pseudoseizures), and to compare the prevalence of a history of sleep events with that in poorly controlled epilepsy. METHODS Prospective study by semistructured interview of the history of event patterns and their clinical associations in 142 patients with video EEG confirmed PNES, and 100 patients with poorly controlled epilepsy. RESULTS 84/142 patients with PNES (59%) and 47/100 with epilepsy (47%) gave a history of events during sleep (p = 0.062). In patients with PNES, significant associations were found between a history of sleep events and: convulsive clinical semiology, antiepileptic drug treatment, fatigue, suicide attempts, mood disorder, and physical abuse. A particularly strong association with social security benefit was also found (odds ratio 4.0, p<0.001). CONCLUSIONS The prevalence of a history of sleep events is similar in PNES and epilepsy, and is of no value in discriminating between the two, although a history of events occurring exclusively during sleep does suggest epileptic seizures. The clinical associations found indicate that a combination of psychopathological and external influences may be important in determining whether or not a patient with PNES gives a history of events during sleep.
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Griffiths PC, Paul A, Khayat Z, Wan KW, King SM, Grillo I, Schweins R, Ferruti P, Franchini J, Duncan R. Understanding the Mechanism of Action of Poly(amidoamine)s as Endosomolytic Polymers: Correlation of Physicochemical and Biological Properties. Biomacromolecules 2004; 5:1422-7. [PMID: 15244460 DOI: 10.1021/bm049936g] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bioresponsive poly(amidoamine)s (PAA)s are currently under development as endosomolytic polymers for intracellular delivery of proteins and genes. Here for the first time, small-angle neutron scattering (SANS) is used to systematically investigate the pH-dependent conformational change of an endosomolytic polymer, the PAA ISA 23. The radius of gyration of the ISA23 was determined as a function of pH and counterion, the aim being to correlate changes in polymer conformation with membrane activity assessed using a rat red blood cell haemolysis assay. With decreasing pH, the ISA23 radius of gyration increased to a maximum (R(g) approximately 80 A) around pH = 3, before subsequently decreasing once more. At high pH and therefore high ionic strengths, the polymer is negatively charged and adopts a rather compact structure (R(g) approximately 20 A), presumably with the dissociated carboxylic groups on the exterior of the polymer coil. At low pH, the coil again collapses (R(g) < 20 A), presumably due to the effects of the high ionic strength. It is concluded that the nature of the salt form has no direct bearing on the size of the polymer coil, but it does indirectly determine the prevailing pH and, hence, polymer conformation. Pulsed-gradient spin-echo NMR measurements were in good agreement with the SANS estimates of the radius of gyration, although ISA23 polydispersity does complicate the data interpretation/comparison. These results support the proposed mode of action of PAAs, namely a coil expansion on passing from a neutral pH (extracellular) to an acidic pH (endosomal and lysosomal) environments. The results do, however, suggest that the charge on the polymer shows a closer correlation with the haemolysis activity rather than the polymer conformation.
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McGonigal A, Russell AJC, Mallik AK, Oto M, Duncan R. Use of short term video EEG in the diagnosis of attack disorders. J Neurol Neurosurg Psychiatry 2004; 75:771-2. [PMID: 15090577 PMCID: PMC1763561 DOI: 10.1136/jnnp.2003.024893] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Distinguishing epileptic from psychogenic non-epileptic seizures (PNES) often requires video electroencephalography (EEG) recording. Inpatient recording is a limited resource; some evidence suggests that short term video EEG (SVEEG) is useful, but its role in practice has yet to be evaluated. OBJECTIVE To assess the usefulness of SVEEG in the diagnosis of attack disorders. METHODS One hundred and forty three SVEEG recordings were performed during an 18 month period. RESULTS A diagnostic event was recorded in 72 of 143 (50.3%): PNES (n = 51), epilepsy (n = 7), or other attacks, such as movement disorders (n = 14). CONCLUSIONS SVEEG is a robust and useful diagnostic technique, which complements existing resources.
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Espie CA, Watkins J, Curtice L, Espie A, Duncan R, Ryan JA, Brodie MJ, Mantala K, Sterrick M. Psychopathology in people with epilepsy and intellectual disability; an investigation of potential explanatory variables. J Neurol Neurosurg Psychiatry 2003; 74:1485-92. [PMID: 14617702 PMCID: PMC1738251 DOI: 10.1136/jnnp.74.11.1485] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES There are few studies on epilepsy and psychopathology in people with intellectual disability (mental retardation) despite epilepsy prevalence rates that are thirty times higher than in the general population. The aims of this study, therefore, were to identify reliable, epilepsy-specific predictors of psychiatric and behavioural disorder in these patients, and to investigate reliable predictors of carer stress. METHODS A database of 685 patients was compiled, from which 250 were randomly selected. Structured interviews were completed on 186 of these 250 patients (74%) (108 men, 78 women; mean age (SD) 35.5 (10.1)) comprising descriptive, clinical and functional components, and validated measures of psychopathology for which comparative data were available. Logistic and linear regression methods were used to identify predictors. RESULTS One-third of patients with epilepsy and intellectual disability met criteria for possible psychiatric disorder, particularly affective/neurotic disorder; twice the comparison rates for intellectual disability alone. Behavioural problem levels, however, were lower than population norms. Regression models explaining modest amounts of variance (R(2)< or =24%) suggested certain seizure phenomena (greater seizure severity, more seizures in past month, lesser tendency to loss of consciousness during seizures) as particular risk factors for psychiatric disorder. General disability factors such as level of intellectual, sensory or motor disability and side effects of medication, however, contributed more to explaining behavioural problems. Around half of the family carers reported significant stress, and one-third exhibited clinically significant anxiety symptoms. Younger carers were more stressed, and side effects from patients' medication also contributed to carer stress. CONCLUSIONS Although epilepsy in itself may be a risk factor for psychopathology in a minority of people with intellectual disability, some epilepsy-specific factors may predict psychiatric disorder. Behavioural problems need to be considered separately from psychiatric disorder because general factors, more closely associated with disability, are stronger predictors of their occurrence.
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Oto M, Russell AJC, McGonigal A, Duncan R. Misdiagnosis of epilepsy in patients prescribed anticonvulsant drugs for other reasons. BMJ 2003; 326:326-7. [PMID: 12574049 PMCID: PMC1125187 DOI: 10.1136/bmj.326.7384.326] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Duncan R. Many universities do teach professionalism. BRITISH JOURNAL OF NURSING (MARK ALLEN PUBLISHING) 2002; 11:1297. [PMID: 12481763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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Stephens S, Beyer B, Balthazar-Stablein U, Duncan R, Kostacos M, Lukoma M, Green GR, Poccia D. Two kinase activities are sufficient for sea urchin sperm chromatin decondensation in vitro. Mol Reprod Dev 2002; 62:496-503. [PMID: 12112583 DOI: 10.1002/mrd.90005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Decondensation of compact and inactive sperm chromatin by egg cytoplasm at fertilization is necessary to convert the male germ cell chromatin to an active somatic form. We studied decondensation of sea urchin sperm nuclei in a cell-free extract of sea urchin eggs to define conditions promoting decondensation. We find that egg cytosol specifically phosphorylates two sperm-specific (Sp) histones in vitro in the same regions as in vivo. This activity is blocked by olomoucine, an inhibitor of cdc2-like kinases, but not by chelerythrine, an inhibitor of protein kinase C (PKC). PKC phosphorylates and solubilizes the sperm nuclear lamina, one requirement for decondensation. Olomoucine, which does not inhibit lamina removal, blocks sperm nuclear decondensation in the same concentration range over which it is effective in blocking Sp histone phosphorylation. In a system free of other soluble proteins, neither PKC nor cdc2 alone elicit sperm chromatin decondensation, but the two act synergistically to decondense sperm nuclei. We conclude that two kinases activities are sufficient for sea urchin male pronuclear decondensation in vitro, a lamin kinase (PKC) and a cdc2-like Sp histone kinase.
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McGonigal A, Oto M, Russell AJC, Greene J, Duncan R. Outpatient video EEG recording in the diagnosis of non-epileptic seizures: a randomised controlled trial of simple suggestion techniques. J Neurol Neurosurg Psychiatry 2002; 72:549-51. [PMID: 11909925 PMCID: PMC1737844 DOI: 10.1136/jnnp.72.4.549] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess the yield of recorded habitual non-epileptic seizures during outpatient video EEG, using simple suggestion techniques based on hyperventilation and photic stimulation. DESIGN Randomised controlled trial of "suggestion" v "no suggestion" during outpatient video EEG recording. SETTING Regional epilepsy service (tertiary care; single centre). PARTICIPANTS 30 patients (22 female, 8 male), aged over 16 years, with a probable clinical diagnosis of non-epileptic seizures; 15 were randomised to each group. MAIN OUTCOME MEASURES Yield of habitual non-epileptic seizures recorded, and requirement for additional inpatient video EEG. RESULTS 10/15 patients had habitual non-epileptic seizures with suggestion; 5/15 had non-epileptic seizures with no suggestion (p = 0.058; NS); 8/9 patients with a history of previous events in medical settings had non-epileptic seizures recorded during study. Logistic regression analysis with an interaction clause showed a significant effect of suggestion in patients with a history of previous events in medical settings (p = 0.003). An additional inpatient video-EEG was avoided in 14 of the 30 patients (47%). CONCLUSIONS Habitual non-epileptic seizures can be recorded reliably during short outpatient video EEG in selected patients. Simple (non-invasive) suggestion techniques increase the yield at least in the subgroup with a history of previous events in medical settings. Inpatient video EEG can be avoided in some patients.
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Richardson SC, Pattrick NG, Man YK, Ferruti P, Duncan R. Poly(amidoamine)s as potential nonviral vectors: ability to form interpolyelectrolyte complexes and to mediate transfection in vitro. Biomacromolecules 2002; 2:1023-8. [PMID: 11710005 DOI: 10.1021/bm010079f] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Poly(amidoamine)s (PAAs) are water-soluble polymers that display pH-dependent membrane activity. PAAs have the potential to act as a synthetic alternative to fusogenic peptides and thus promote endosomal escape. The purpose of this study was to investigate for the first time whether PAA have the ability to complex DNA, protect it from nuclease degradation and to promote transfection in vitro. PAAs ISA 1 (Mn 6900) and ISA 23 (Mn 10,500) and their 2-phenylethylamine containing analogues ISA 4 and ISA 22 (Mn approximately 8000) were studied. All PAAs retarded the electrophoretic mobility of lambda Hind III DNA demonstrating interpolyelectrolyte complex (IPEC) formation and toroids of 80-150 nm in diameter (10:1 polymer excess) were visible using TEM. DNase II inhibition was observed. At a polymer:DNA ratio of 10:1, this was ISA 1(89.6 +/- 6.1%), ISA 4 (92.2 +/- 11.2%), ISA 22 (69.4 +/- 3.7%), and ISA 23 (58.0 +/- 10.0%). PAAs demonstrated the ability to mediate pSV beta-galactosidase transfection of HepG2 cells. At a vector:DNA mass ratio of 5:1, ISA 23 showed equivalent transfection ability compared with polyethylenimine and LipofectIN and was more effective than LipofectACE. These properties suggest that PAAs warrant further development as endosomolytic vectors.
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Lee N, Bertholet S, Debrabant A, Muller J, Duncan R, Nakhasi HL. Programmed cell death in the unicellular protozoan parasite Leishmania. Cell Death Differ 2002. [PMID: 11803374 DOI: 10.1038/sj/cdd/4400952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
In the present study we have demonstrated some features characterizing programmed cell death (PCD) in the unicellular protozoan parasite Leishmania donovani, the causative agent of visceral Leishmaniasis. We report that PCD is initiated in stationary phase cultures of promastigotes and both in actively growing cultures of axenic amastigotes and promastigotes upon treatment with anti Leishmanial drugs (Pentostam and amphotericin B). However, the two cell types respond to antileishmanial drugs differently. The features of PCD in L. donovani promastigotes are nuclear condensation, nicked DNA in the nucleus, DNA ladder formation, increase in plasma membrane permeability, decrease in the mitochondrial membrane potential (DeltaPsi m) and induction of a PhiPhiLux (PPL)-cleavage activity. PCD in both stationary phase culture and upon induction by amphotericin B resulted first in the decrease of mitochondrial membrane potential followed by simultaneous change in plasma membrane permeability and induction of PPL-cleavage activity. Of the total PPL-cleavage activity, several caspase inhibitors inhibited a significant amount (21-34%). Inhibitors of cathepsin or calpain did not inhibit PPL-cleavage activity. Taken together this study demonstrates that the characteristic features of PCD exist in unicellular protozoan Leishmania donovani. The implication of PCD on the Leishmania pathogenesis is discussed.
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Lee N, Bertholet S, Debrabant A, Muller J, Duncan R, Nakhasi HL. Programmed cell death in the unicellular protozoan parasite Leishmania. Cell Death Differ 2002; 9:53-64. [PMID: 11803374 DOI: 10.1038/sj.cdd.4400952] [Citation(s) in RCA: 211] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2001] [Revised: 07/23/2001] [Accepted: 08/31/2001] [Indexed: 11/08/2022] Open
Abstract
In the present study we have demonstrated some features characterizing programmed cell death (PCD) in the unicellular protozoan parasite Leishmania donovani, the causative agent of visceral Leishmaniasis. We report that PCD is initiated in stationary phase cultures of promastigotes and both in actively growing cultures of axenic amastigotes and promastigotes upon treatment with anti Leishmanial drugs (Pentostam and amphotericin B). However, the two cell types respond to antileishmanial drugs differently. The features of PCD in L. donovani promastigotes are nuclear condensation, nicked DNA in the nucleus, DNA ladder formation, increase in plasma membrane permeability, decrease in the mitochondrial membrane potential (DeltaPsi m) and induction of a PhiPhiLux (PPL)-cleavage activity. PCD in both stationary phase culture and upon induction by amphotericin B resulted first in the decrease of mitochondrial membrane potential followed by simultaneous change in plasma membrane permeability and induction of PPL-cleavage activity. Of the total PPL-cleavage activity, several caspase inhibitors inhibited a significant amount (21-34%). Inhibitors of cathepsin or calpain did not inhibit PPL-cleavage activity. Taken together this study demonstrates that the characteristic features of PCD exist in unicellular protozoan Leishmania donovani. The implication of PCD on the Leishmania pathogenesis is discussed.
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Pattrick NG, Richardson SC, Casolaro M, Ferruti P, Duncan R. Poly(amidoamine)-mediated intracytoplasmic delivery of ricin A-chain and gelonin. J Control Release 2001; 77:225-32. [PMID: 11733090 DOI: 10.1016/s0168-3659(01)00476-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Poly(amidoamine)s (PAAs) are water-soluble synthetic polymers designed to be biodegradable and biocompatible. Moreover, they display membrane disruptive properties in response to a decrease in pH. This attribute confers PAAs with endosomolytic properties in vitro and in vivo. A model system was developed to quantify their ability to promote the endosomal escape of macromolecules that may be interesting as therapeutic agents. Here, two PAAs (ISA 1 and 4) were incubated with B16F10 cells in vitro together with two non-permeant toxins: either ricin A-chain (RTA) or gelonin. The relatively non-toxic PAAs ISA 1 and 4 (IC50>1.5 mg/ml) restored activity to the inherently inert toxins. The IC50 values for the ISA 1/RTA and ISA 1/gelonin combinations were 0.65+/-0.05 and 0.55+/-0.12 mg/ml, respectively. Similarly, when ISA 4 was incubated with a non-toxic combination of RTA and gelonin the IC50 value decreased to 0.57+/-0.03 and 0.43+/-0.26 mg/ml, respectively. In contrast, the neutral polymer dextran and the PAA ISA 22 were unable to mediate this effect. These observations suggest that specific PAA-toxin combinations warrant further development as novel therapeutics.
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Schneider R, Agol VI, Andino R, Bayard F, Cavener DR, Chappell SA, Chen JJ, Darlix JL, Dasgupta A, Donzé O, Duncan R, Elroy-Stein O, Farabaugh PJ, Filipowicz W, Gale M, Gehrke L, Goldman E, Groner Y, Harford JB, Hatzglou M, He B, Hellen CU, Hentze MW, Hershey J, Hershey P, Hohn T, Holcik M, Hunter CP, Igarashi K, Jackson R, Jagus R, Jefferson LS, Joshi B, Kaempfer R, Katze M, Kaufman RJ, Kiledjian M, Kimball SR, Kimchi A, Kirkegaard K, Koromilas AE, Krug RM, Kruys V, Lamphear BJ, Lemon S, Lloyd RE, Maquat LE, Martinez-Salas E, Mathews MB, Mauro VP, Miyamoto S, Mohr I, Morris DR, Moss EG, Nakashima N, Palmenberg A, Parkin NT, Pe'ery T, Pelletier J, Peltz S, Pestova TV, Pilipenko EV, Prats AC, Racaniello V, Read GS, Rhoads RE, Richter JD, Rivera-Pomar R, Rouault T, Sachs A, Sarnow P, Scheper GC, Schiff L, Schoenberg DR, Semler BL, Siddiqui A, Skern T, Sonenberg N, Sossin W, Standart N, Tahara SM, Thomas AA, Toulmé JJ, Wilusz J, Wimmer E, Witherell G, Wormington M. New ways of initiating translation in eukaryotes. Mol Cell Biol 2001; 21:8238-46. [PMID: 11710333 PMCID: PMC99989 DOI: 10.1128/mcb.21.23.8238-8246.2001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Selvapandiyan A, Duncan R, Debrabant A, Bertholet S, Sreenivas G, Negi NS, Salotra P, Nakhasi HL. Expression of a mutant form of Leishmania donovani centrin reduces the growth of the parasite. J Biol Chem 2001; 276:43253-61. [PMID: 11544261 DOI: 10.1074/jbc.m106806200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leishmania donovani, a protozoan parasite, causes visceral disease in humans. To identify genes that control growth, we have isolated for the first time in the order Kinetoplastida a gene encoding for centrin from L. donovani. Centrin is a calcium-binding cytoskeletal protein essential for centrosome duplication or segregation. Protein sequence similarity and immunoreactivity confirmed that Leishmania centrin is a homolog of human centrin 2. Immunofluorescence analysis localized the protein in the basal body. Calcium binding analysis revealed that its C-terminal Ca(2+) binding domain binds 16-fold more calcium than the N-terminal domain. Electrophoretic mobility shift of centrin treated with EGTA and abrogation of the shift in its mutants lacking a Ca(2+) binding site suggest that Ca(2+) binding to these regions may have a role in the protein conformation. The levels of centrin mRNA and protein were high during the exponential growth of the parasite in culture and declined to a low level in the stationary phase. Expression of N-terminal-deleted centrin in the parasite significantly reduces its growth rate, and it was found that significantly more cells are arrested in the G(2)/M stage than in control cells. These studies indicate that centrin may have a functional role in Leishmania growth.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Blotting, Western
- Calcium/metabolism
- Calcium-Binding Proteins/chemistry
- Cell Cycle
- Chromosomal Proteins, Non-Histone/chemistry
- Cloning, Molecular
- Cytoskeleton/metabolism
- Egtazic Acid/pharmacology
- Flow Cytometry
- Gene Deletion
- Immunoblotting
- Leishmania donovani/chemistry
- Leishmania donovani/genetics
- Leishmania donovani/physiology
- Microscopy, Fluorescence
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Phylogeny
- Plasmids/metabolism
- Protein Conformation
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Messenger/metabolism
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Time Factors
- Transfection
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Pedone E, Cavallaro G, Richardson SC, Duncan R, Giammona G. alpha,beta-poly(asparthylhydrazide)-glycidyltrimethylammonium chloride copolymers (PAHy-GTA): novel polymers with potential for DNA delivery. J Control Release 2001; 77:139-53. [PMID: 11689267 DOI: 10.1016/s0168-3659(01)00459-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Hydrophilic polycations form complexes when mixed with plasmids. Following functionalisation with glycidyltrimethylammonium chloride (GTA) alpha,beta-poly(asparthylhydrazide) (PAHy), a water-soluble synthetic macromolecule, becomes polycationic and potentially useful for systemic gene delivery. Initially the biocompatibility of PAHy and PAHy-GTA derivatives with different degrees of positive charge substitution were studied and it was shown that PAHy-GTA was neither haemolytic nor cytotoxicity up to 1 mg/ml. After intravenous injection (125)I-labelled PAHy-GTA derivative containing 46 mol% (PAHy-GTA(b)) of trimethylammonium groups did not accumulate in the liver (4.1+/-0.9% of the recovered dose after 1 h) but was subjected to renal excretion (45+/-21% of the recovered dose was in the kidneys after 1 h). PAHy-GTA formed complexes with DNA (gel retardation) and they protected against degradation by DNase II. Finally the ability of the PAHy-GTA(b) derivative to mediate the transfection of HepG2 cells using the marker gene beta-galactosidase was studied. The optimum plasmid/polymer mass ratio was examined in comparison to LipofectACE, Lipofectin and polyethylenimine.
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95
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Hreczuk-Hirst D, Chicco D, German L, Duncan R. Dextrins as potential carriers for drug targeting: tailored rates of dextrin degradation by introduction of pendant groups. Int J Pharm 2001; 230:57-66. [PMID: 11672956 DOI: 10.1016/s0378-5173(01)00859-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
There is a recognised need to identify new biodegradable polymers suitable for development as targetable drug carriers. The aim of this study was to determine the rate of degradation of two dextrin fractions (Mw 15.5 and 51 KDa) by alpha-amylase and liver lysosomal enzymes (tritosomes). Also experiments were conducted to discover whether backbone modification by succinolyation (1-34 mol%) or pendant group incorporation (e.g. doxorubicin) could be used to tailor the rate of polymer degradation. Dextrin (alpha-1,4 polyglucose) is a natural polymer used clinically as a peritoneal dialysis solution and as a controlled drug delivery formulation. Size exclusion chromatography (SEC) showed that dextrin was degraded rapidly (within 20 min) by rat plasma and porcine pancreatic alpha-amylase. In contrast over 48 h no degradation was observed in the presence of tritosomes. The rate of alpha-amylase degradation of succinoylated dextrins (Mw approximately 51 KDa) was dependant on the degree of modification (dextrin >1>5>15>34 mol% succinoylation). Dextrin-doxorubicin conjugates were prepared from the 15 and 34 mol% succinoylated intermediates to have a doxorubicin loading of 8 and 12 wt.%, respectively. These doxorubicin conjugates were more stable than their parent intermediates, and SEC showed an apparently higher molecular weight. The drug conjugates did however degrade slowly over 7 days to release oligosaccharide-doxorubicin species. This fundamental study demonstrates the possibility of controlling the rate of dextrin enzymolysis by backbone modification and thus affords the potential to rationally design dextrin-drug conjugates for specific applications as targetable carriers.
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96
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Duncan R, Alvarez R, Jaffe CL, Wiese M, Klutch M, Shakarian A, Dwyer D, Nakhasi HL. Early response gene expression during differentiation of cultured Leishmania donovani. Parasitol Res 2001; 87:897-906. [PMID: 11728012 DOI: 10.1007/s004360100464] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The promastigote form of the unicellular parasite, Leishmania donovani, must differentiate into the amastigote form to establish an infection in a mammalian host. Identification of genes whose expression changes during differentiation could help reveal mechanisms of Leishmania gene regulation and identify targets for controlling the diseases caused by this human pathogen. Two genomic clones were isolated, P9 that is more highly expressed in promastigotes than in axenic amastigotes and A14 that is preferentially expressed in axenic amastigotes. Analysis of the DNA sequences revealed open reading frames that would encode 55.5 kDa and 100 kDa proteins, respectively, with no homology to known proteins. The mRNA level for these genes during 24 h time courses of parasite differentiation in culture was compared to two genes known to be differentially expressed, c-lpk2 and mkk. Changes in RNA level occurred within 2 h for each gene and continued in advance of morphological changes. The expression levels of these four genes in axenic amastigotes correlated with results from animal-derived parasites.
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97
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Hopewel JW, Duncan R, Wilding D, Chakrabarti K. Preclinical evaluation of the cardiotoxicity of PK2: a novel HPMA copolymer-doxorubicin-galactosamine conjugate antitumour agent. Hum Exp Toxicol 2001; 20:461-70. [PMID: 11776408 DOI: 10.1191/096032701682693017] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
PK2 is a polymeric anticancer conjugate composed of an N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer backbone and pendant doxorubicin (DOX) linked via a Gly-Phe-Leu-Gly peptide spacer. Additionally galactose residues are present to facilitate liver targeting. To justify clinical evaluation of PK2 it was necessary to determine its late cardiotoxicity compared to that of free DOX. A well standardised Sprague-Dawley rat model was used with either intravenous (i.v.) administration (4, 8 and 12 mg/kg DOX equivalent) or intraperitoneal (i.p.) administration (12, 18, 24 and 36 mg/kg DOX equivalent) of PK2. This variation in the route was due to the limited solubility of PK2 at higher doses. PK2 showed two to three times less acute toxicity (assessed by the maximum reduction in body weight in the first 2 weeks) than free DOX, and both compounds were less toxic when given i.p.. No animals given PK2 i.v. showed clinical signs of cardiotoxicity, the only toxicity seen was abnormal tooth growth (approximately 50% of the animals receiving 12 mg/kg, DOX equivalent). In contrast, several animals receiving free DOX (1-4 mg/kg) i.v. died due to cardiotoxicity in an approximately dose-related manner. All animals receiving free DOX (4 mg/kg) died by 12 weeks. Following i.p. administration of PKZ there were only two late deaths related to cardiotoxicity and these were in the 24 mg/kg DOX equivalent group. All animals receiving PK2 at the highest dose (36 mg/kg DOX equivalent) died within 4 weeks, cardiotoxicity was not the main contributing factor. In this study, PK2 displayed a approximately 5-fold reduction in cardiotoxicity relative to free DOX and this supported the progression of PK2 into early clinical investigation.
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98
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Satchi R, Connors TA, Duncan R. PDEPT: polymer-directed enzyme prodrug therapy. I. HPMA copolymer-cathepsin B and PK1 as a model combination. Br J Cancer 2001; 85:1070-6. [PMID: 11592781 PMCID: PMC2375098 DOI: 10.1054/bjoc.2001.2026] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Polymer-directed enzyme prodrug therapy (PDEPT) is a novel two-step antitumour approach using a combination of a polymeric prodrug and polymer-enzyme conjugate to generate cytotoxic drug selectively at the tumour site. In this study the polymeric prodrug N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-Gly-Phe-Leu-Gly-doxorubicin conjugate PK1 (currently under Phase II clinical evaluation) was selected as the model prodrug, and HPMA copolymer-cathepsin B as a model for the activating enzyme conjugate. Following polymer conjugation (yield of 30-35%) HPMA copolymer-cathepsin B retained approximately 20-25% enzymatic activity in vitro. To investigate pharmacokinetics in vivo,(125)I-labelled HPMA copolymer-cathepsin B was administered intravenously (i.v.) to B16F10 tumour-bearing mice. HPMA copolymer-cathespin B exhibited a longer plasma half-life (free cathepsin B t(1/2alpha)= 2.8 h; bound cathepsin B t(1/2alpha)= 3.2 h) and a 4.2-fold increase in tumour accumulation compared to the free enzyme. When PK1 (10 mg kg(-1)dox-equiv.) was injected i.v. into C57 mice bearing subcutaneously (s.c.) palpable B16F10 tumours followed after 5 h by HPMA copolymer-cathepsin B there was a rapid increase in the rate of dox release within the tumour (3.6-fold increase in the AUC compared to that seen for PK1 alone). When PK1 and the PDEPT combination were used to treat established B16F10 melanoma tumour (single dose; 10 mg kg(-1)dox-equiv.), the antitumour activity (T/C%) seen for the combination PDEPT was 168% compared to 152% seen for PK1 alone, and 144% for free dox. Also, the PDEPT combination showed activity against a COR-L23 xenograft whereas PK1 did not. PDEPT has certain advantages compared to ADEPT and GDEPT. The relatively short plasma residence time of the polymeric prodrug allows subsequent administration of polymer-enzyme without fear of prodrug activation in the circulation and polymer-enzyme conjugates have reduced immunogenicity. This study proves the concept of PDEPT and further optimisation is warranted.
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99
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Duncan R. Not doing nothing. AUSTRALIAN NURSING JOURNAL (JULY 1993) 2001; 9:46-7. [PMID: 11908124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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100
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Searle F, Gac-Breton S, Keane R, Dimitrijevic S, Brocchini S, Sausville EA, Duncan R. N-(2-hydroxypropyl)methacrylamide copolymer-6-(3-aminopropyl)-ellipticine conjugates. Synthesis, in vitro, and preliminary in vivo evaluation. Bioconjug Chem 2001; 12:711-8. [PMID: 11562189 DOI: 10.1021/bc0001544] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ellipticine derivatives have potential as anticancer drugs. Their clinical use has been limited, however, by poor solubility and host toxicity. As N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-anticancer conjugates are showing promise in early clinical trials, a series of novel HPMA copolymer conjugates have been prepared containing the 6-(3-aminopropyl)-ellipticine derivative (APE, NSC176328). Drug was linked to the polymer via GFLG or GG peptide side chains. To optimize biological behavior, HPMA copolymer-GFLG-APE conjugates with different drug loading (total APE: 2.3-7% w/w; free APE: <0.1% w/w) were synthesized. Conjugation of APE to HPMA copolymers considerably increased its aqueous solubility (>10-fold). HPMA copolymer-GG-APE did not liberate drug in the presence of isolated lysosomal enzymes (tritosomes), but HPMA copolymer-GFLG-APE released APE to a maximum of 60% after 5 h. The rate of drug release was influenced by drug loading; lower loading led to greater release. Whereas free APE (35 microg/mL) caused significant hemolysis (50% after 1 h), HPMA copolymer-APE conjugates were not hemolytic up to 300 microg/mL (APE-equiv). As would be expected from its cellular pharmacokinetics, HPMA copolymer-GFLG-APE was >75 times less cytotoxic than free drug (IC(50) approximately 0.4 microg/mL) against B16F10 melanoma in vitro. However, in vivo when tested in mice bearing s.c. B16F10 melanoma, HPMA copolymer-GFLG-APE (1-10 mg/kg single dose, APE-equiv) given i.p. was somewhat more active (highest T/C value of 143%) than free APE (1 mg/kg) (T/C =127%). HPMA copolymer-APE conjugates warrant further evaluation as potential anticancer agents.
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