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Tan E, Hsu A, Eng P, Tan K, Lee P, Raghuram J, Lo C, Loo C, Cheah F, Toh C, Leong S, Lim W, Lau J, Hui K. P-123 Molecular profiling of lung cancers: Can it be used as a clinicaltool? Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)80617-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Togasaki DM, Hsu A, Samant M, Farzan B, DeLanney LE, Langston JW, Di Monte DA, Quik M. The Webcam system: a simple, automated, computer-based video system for quantitative measurement of movement in nonhuman primates. J Neurosci Methods 2005; 145:159-66. [PMID: 15922034 DOI: 10.1016/j.jneumeth.2004.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 11/01/2004] [Accepted: 12/22/2004] [Indexed: 11/26/2022]
Abstract
Investigations using models of neurologic disease frequently involve quantifying animal motor activity. We developed a simple method for measuring motor activity using a computer-based video system (the Webcam system) consisting of an inexpensive video camera connected to a personal computer running customized software. Images of the animals are captured at half-second intervals and movement is quantified as the number of pixel changes between consecutive images. The Webcam system allows measurement of motor activity of the animals in their home cages, without devices affixed to their bodies. Webcam quantification of movement was validated by correlation with measures simultaneously obtained by two other methods: measurement of locomotion by interruption of infrared beams; and measurement of general motor activity using portable accelerometers. In untreated squirrel monkeys, correlations of Webcam and locomotor activity exceeded 0.79, and correlations with general activity counts exceeded 0.65. Webcam activity decreased after the monkeys were rendered parkinsonian by treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), but the correlations with the other measures of motor activity were maintained. Webcam activity also correlated with clinical ratings of parkinsonism. These results indicate that the Webcam system is reliable under both untreated and experimental conditions and is an excellent method for quantifying motor activity in animals.
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Hsu A, Miller NR, Evans PM, Bamber JC, Webb S. Feasibility of using ultrasound for real-time tracking during radiotherapy. Med Phys 2005; 32:1500-12. [PMID: 16013706 DOI: 10.1118/1.1915934] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
This study was designed to examine the feasibility of utilizing transabdominal ultrasound for real-time monitoring of target motion during a radiotherapy fraction. A clinical Acuson 128/XP ultrasound scanner was used to image various stationary and moving phantoms while an Elekta SL25 linear accelerator radiotherapy treatment machine was operating. The ultrasound transducer was positioned to image from the outer edge of the treatment field at all times. Images were acquired to videotape and analyzed using in-house motion tracking algorithms to determine the effect of the SL25 on the quality of the displacement measurements. To determine the effect on the dosimetry of the presence of the transducer, dose distributions were examined using thermoluminescent dosimeters loaded into an Alderson Rando phantom and exposed to a 10 x 10 cm2 treatment field with and without the ultrasound transducer mounted 2.5 cm outside the field edge. The ultrasound images acquired a periodic noise that was shown to occur at the pulsing frequency of the treatment machine. Images of moving tissue were analyzed and the standard deviation on the displacement estimates within the tissue was identical with the SL25 on and off. This implies that the periodic noise did not significantly degrade the precision of the tracking algorithm (which was better than 0.01 mm). The presence of the transducer at the surface of the phantom presented only a 2.6% change to the dose distribution to the volume of the phantom. The feasibility of ultrasonic motion tracking during radiotherapy treatment is demonstrated. This presents the possibility of developing a noninvasive, real-time and low-cost method of tracking target motion during a treatment fraction.
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Stone GW, Walker ND, Hsu A, Babin A, Liu B, Keim BD, Teague W, Mitchell D, Leben R. Hurricane Ivan's Impact along the northern Gulf Of Mexico. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005eo480001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
This study investigated the use of interventional bronchoscopic techniques in the management of patients with symptomatic tracheobronchial stenosis from tuberculosis. The current authors evaluated their experience with interventional bronchoscopic techniques in 21 consecutive patients at the Singapore General Hospital, Singapore, from November 1994 to March 2001. All patients underwent rigid bronchocopy using the Dumon rigid ventilating bronchosope under general anaesthesia. A combination of techniques was used (mechanical or balloon dilatation, Nd-YAG laser and stenting using the Dumon stent). The mean+/-SD increase in luminal diameter of the tracheal lesions was from 4.5+/-2.5 mm pre-procedure to 11.9+/-1.7 mm post-procedure, whereas that for the mainstem bronchi stenosis was from 2.6+/-1.0 mm to 8.3+/-2.4 mm. All patients had immediate relief of symptoms post-intervention. Two patients who presented with acute respiratory failure could be weaned off mechanical ventilation immediately post-procedure. At the end of the study period, 52% (11 out of 21) remained asymptomatic. Bronchoscopic intervention provided immediate symptomatic relief in all of the studied patients. However, repeated sessions may be required to maintain this improvement. It is concluded that interventional bronchoscopic techniques are useful in the management of patients with tracheobronchial stenosis from tuberculosis.
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Dyer LA, Letourneau DK, Dodson CD, Tobler MA, Stireman JO, Hsu A. ECOLOGICAL CAUSES AND CONSEQUENCES OF VARIATION IN DEFENSIVE CHEMISTRY OF A NEOTROPICAL SHRUB. Ecology 2004. [DOI: 10.1890/03-0233] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Hsu A, Togasaki DM, Bezard E, Sokoloff P, Langston JW, Di Monte DA, Quik M. Effect of the D3 dopamine receptor partial agonist BP897 [N-[4-(4-(2-methoxyphenyl)piperazinyl)butyl]-2-naphthamide] on L-3,4-dihydroxyphenylalanine-induced dyskinesias and parkinsonism in squirrel monkeys. J Pharmacol Exp Ther 2004; 311:770-7. [PMID: 15226382 DOI: 10.1124/jpet.104.071142] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although l-3,4-dihydroxyphenylalanine (L-dopa) is one of the most effective therapies for Parkinson's disease, continued treatment may result in excessive involuntary movements known as L-dopa-induced dyskinesias (LIDs). Because LIDs can become dose-limiting, there is great interest in finding ways to ameliorate or prevent this troubling side effect of L-dopa therapy. It was recently reported that the D3 receptor partial agonist BP897 [N-[4-(4-(2-methoxyphenyl)piperazinyl)butyl]-2-naphthamide] reduces LIDs without diminishing antiparkinsonian effects of L-dopa in macaques. In the present study, we tested the effects of BP897 on LIDs in squirrel monkeys, a nonhuman primate particularly prone to dyskinesias. Parkinsonism was induced using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Animals were then gavaged with L-dopa/carbidopa (7.5 or 15 mg/kg/dose) without and with BP897. The effects of BP897 treatment were evaluated on several components of LIDs, including time course, peak dyskinesias, and area under the curve (AUC), a measure that encompasses both peak and duration of the response. Analyses of the time course and overall dyskinetic response (AUC) showed that BP897 significantly reduced LIDs but at the expense of the antiparkinsonian effect of L-dopa. BP897 had no significant effect on peak dyskinesias. Correlation studies showed that beneficial effects of BP897 on dyskinesias were linked to a decline in the antiparkinsonian action of L-dopa. Analyses of a subgroup of animals with mild/moderate parkinsonism yielded comparable results. Thus, in squirrel monkeys in contrast to macaques, BP897 fails to exert an antidyskinetic effect without diminishing the antiparkinsonian effects of L-dopa. These results suggest that BP897 may be less effective than originally anticipated for treating LIDs in Parkinson's disease.
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Hsu A. Through the Student's Eyes: Fighting Medical School Tuition Hikes in New York. AMA J Ethics 2002; 4:virtualmentor.2002.4.6.prsp3-0206. [PMID: 23269191 DOI: 10.1001/virtualmentor.2002.4.6.prsp3-0206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Buss N, Snell P, Bock J, Hsu A, Jorga K. Saquinavir and ritonavir pharmacokinetics following combined ritonavir and saquinavir (soft gelatin capsules) administration. Br J Clin Pharmacol 2001; 52:255-64. [PMID: 11560557 PMCID: PMC2014551 DOI: 10.1046/j.0306-5251.2001.01452.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To investigate the influence of combined ritonavir (RTV) and saquinavir (soft-gelatin capsule formulation; SQV) on systemic exposure to SQV with a view to optimizing the dosing regimen of combined RTV and SQV antiretroviral therapy. METHODS In this open labelled, randomized, parallel group study, SQV and RTV were administered twice daily for 14 days to groups of eight healthy subjects. The two antiretrovirals were either administered alone (800 mg SQV, regimen A, and 400 mg RTV, B) or in combination at various dose levels (RTV : SQV: 400 : 400 mg, C; 300 : 600 mg, D; 200 : 800 mg, E; 300 : 800 mg, F; 400 : 800 mg, G; and 400 : 600 mg, H). Pharmacokinetic parameters of saquinavir and ritonavir were determined and adverse events, vital signs, and clinical laboratory variables recorded. RESULTS RTV substantially increased the plasma concentration of saquinavir for all dose combinations, compared with SQV alone. Based on the primary statistical analysis there was an overall 17-, 22-, and 23-fold increase in saquinavir AUC(0,24 h) on day 14 with regimens E, F, and G, respectively (with confidence intervals of 10-30, 13-37, and 13-39). The lowest combination dose of RTV (200 : 800 mg; E) significantly increased the saquinavir AUC(0,24 h) from below 5 to 57 microg ml(-1) h, which was higher than the exposure obtained with the 400 : 400 mg twice daily regimen (i.e. 36 microg ml(-1) h). RTV also reduced intersubject variability in AUC(0,24 h) for saquinavir from 105% to 32-68%, and C(max)(0,24 h) from 124% to 30-49%. In contrast, SQV showed no clinically significant effect on the pharmacokinetics of ritonavir. The combination regimens were well tolerated, with the least number of adverse events recorded for the 200 : 800 mg (RTV : SQV) combination regimen. CONCLUSIONS RTV significantly increases saquinavir exposure as a consequence of inhibiting SQV metabolism and possibly P-glycoprotein efflux. Pharmacokinetic and safety profiles obtained in the current study indicate that the use of a combination with a lower dose of RTV and a higher dose of SQV than the 400 : 400 mg combination frequently used in clinical practice should be further explored.
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Theunissen FE, David SV, Singh NC, Hsu A, Vinje WE, Gallant JL. Estimating spatio-temporal receptive fields of auditory and visual neurons from their responses to natural stimuli. NETWORK (BRISTOL, ENGLAND) 2001; 12:289-316. [PMID: 11563531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present a generalized reverse correlation technique that can be used to estimate the spatio-temporal receptive fields (STRFs) of sensory neurons from their responses to arbitrary stimuli such as auditory vocalizations or natural visual scenes. The general solution for STRF estimation requires normalization of the stimulus-response cross-correlation by the stimulus autocorrelation matrix. When the second-order stimulus statistics are stationary, normalization involves only the diagonal elements of the Fourier-transformed auto-correlation matrix (the power spectrum). In the non-stationary case normalization requires the entire auto-correlation matrix. We present modelling studies that demonstrate the feasibility and accuracy of this method as well as neurophysiological data comparing STRFs estimated using natural versus synthetic stimulus ensembles. For both auditory and visual neurons, STRFs obtained with these different stimuli are similar, but exhibit systematic differences that may be functionally significant. This method should be useful for determining what aspects of natural signals are represented by sensory neurons and may reveal novel response properties of these neurons.
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Geoffroy JM, Leblond D, Poska R, Brinker D, Hsu A. Unit dose sampling and final product performance: an alternative approach. Drug Dev Ind Pharm 2001; 27:731-43. [PMID: 11694021 DOI: 10.1081/ddc-100107330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This article documents a proposed plan for validation testing for the content uniformity for final blends and finished solid oral dosage forms (SODFs). The testing logic and statistical justification of the plan are presented. The plan provides good assurance that a passing lot will perforin well against the USP tablet content uniformity test. The operating characteristics of the test and the probability of needing to test for blend sampling bias are reported. A case study is presented.
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Patel HH, Hsu A, Moore J, Gross GJ. BW373U86, a delta opioid agonist, partially mediates delayed cardioprotection via a free radical mechanism that is independent of opioid receptor stimulation. J Mol Cell Cardiol 2001; 33:1455-65. [PMID: 11448134 DOI: 10.1006/jmcc.2001.1408] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Opioids have been shown to produce both an early and delayed phase of cardioprotection; however, the signaling pathways involved, particularly in the delayed response, have not been well defined. Therefore, we investigated the potential of BW373U86 (BW), a potent delta opioid agonist, to produce delayed cardioprotection and characterized the role of opioid receptors and oxygen-derived free radicals (OFRs) in this delayed response. All rats underwent 30 min of ischemia followed by 2 h of reperfusion. The rats were divided into four groups. First, rats were pretreated with selective opioid receptor antagonists or the antioxidant, 2-mercaptopropionyl glycine (2-MPG), in the presence of BW and allowed to recover for 24 h before the ischemia-reperfusion protocol. Second, rats were pretreated with BW, allowed to recover for 24 h, and subsequently treated with either opioid antagonists or 2-MPG, 10 min prior to the ischemia-reperfusion protocol. Third, rats underwent ischemic preconditioning (IPC) (1x5 min occlusion) both with and without 2-MPG to determine the role of OFRs in acute cardioprotection. Fourth, rats were pretreated with TAN-67, an opioid agonist known to signal through the delta1 opioid receptor in the presence and absence of 2-MPG. Control rats were injected with saline and allowed to recover for 24 h. BW produced a bell-shaped dose-related reduction in infarct size with a maximal reduction observed at 0.1 mg/kg v control (16+/-3%v 60+/-3%, P<0.001). Surprisingly, the delayed protection induced by BW was only partially blocked by pretreatment with the delta1-selective antagonist, BNTX; however, it was completely blocked by pretreatment with 2-MPG (47+/-5%, P<0.001). Only naloxone given acutely inhibited the protective effects of BW; however, at the dose used, 2-MPG partially reduced the protective effect of acute IPC. TAN-67 (0.1 mg/kg) also produced a significant reduction in infarct size compared to control (18+/-4%v 60+/-3%, P<0.001). This protection was blocked by pretreatment with 2-MPG (42+/-4%, P<0.001). These data suggest that BW and TAN-67 mediate delayed cardioprotection via a free radical mechanism that appears to be only partially dependent on delta opioid receptor stimulation. Furthermore, it is the early burst in OFRs that is crucial to initiating the protective effect.
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Johnson AJ, song X, Hsu A, Chen C. Apoptosis signaling pathways mediated by cyclooxygenase-2 inhibitors in prostate cancer cells. ADVANCES IN ENZYME REGULATION 2001; 41:221-35. [PMID: 11384747 DOI: 10.1016/s0065-2571(00)00015-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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115
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Hussain I, Randolph D, Brody SL, Song SK, Hsu A, Kahn AM, Chaplin DD, Hamilos DL. Induction, distribution and modulation of upper airway allergic inflammation in mice. Clin Exp Allergy 2001; 31:1048-59. [PMID: 11467996 DOI: 10.1046/j.1365-2222.2001.01129.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND To further elucidate mechanisms of human allergic rhinosinusitis, we studied the induction, distribution and modulation of allergen-induced upper airway inflammation in a BALB/c mouse model. METHODS Allergic inflammation induced with ovalbumin (OVA) by intraperitoneal (IP) injection in alum was compared to repeated intranasal instillation. The type and distribution of inflammatory cells was compared in the respiratory and olfactory epithelial compartments. Eosinophil distribution was assessed using Scarlet Red stain and a polyclonal antibody recognizing eosinophil major basic protein (MBP). The role of interleukin (IL)-5 in upper airway inflammation was tested by administration of polyclonal anti-IL-5 antibody during the sensitization protocol. RESULTS Unsensitized control mice receiving saline failed to develop upper airway eosinophil infiltration. IP OVA-sensitized mice developed marked upper airway mucosal eosinophil infiltration after aerosol OVA challenge, whereas repeated intranasal instillation of OVA produced qualitatively similar, but less intense eosinophil infiltration. Using either sensitization protocol, eosinophil infiltration was seen in areas of the lower portion of the nasal septum, the floor and the lower lateral walls of the mid-caudal region of the nasal cavity. Immunofluorescence staining for MBP confirmed this distribution of eosinophils but also demonstrated some eosinophils in the maxillary sinuses and in circumscribed regions of the ethmoturbinates. All areas of eosinophil infiltration were lined by respiratory epithelium. The selective infiltration of respiratory but not olfactory epithelium by eosinophils was unassociated with a measurable induction of epithelial ICAM-1 or eotaxin expression. OVA-induced upper airway eosinophil infiltration was found to be IL-5 dependent, since administration of a polyclonal anti-IL-5 antibody (TRFK-5) during OVA sensitization resulted in a marked modulation (80% decrease) in eosinophil infiltration in response to subsequent OVA challenge. CONCLUSION The mouse upper airway, specifically in areas containing respiratory epithelium, is a target for OVA-induced allergic inflammation. This selective infiltration of respiratory, but not olfactory, epithelium is, in part, dependent upon IL-5. This model is useful for further dissection of the inflammatory response with genetic manipulations and targeted immunological approaches.
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Gerber JG, Rosenkranz S, Segal Y, Aberg J, D'Amico R, Mildvan D, Gulick R, Hughes V, Flexner C, Aweeka F, Hsu A, Gal J. Effect of ritonavir/saquinavir on stereoselective pharmacokinetics of methadone: results of AIDS Clinical Trials Group (ACTG) 401. J Acquir Immune Defic Syndr 2001; 27:153-60. [PMID: 11404537 DOI: 10.1097/00126334-200106010-00010] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED The effect of ritonavir 400 mg/saquinavir 400 mg twice daily on the stereoselective pharmacokinetics of methadone was examined in 12 HIV-infected, methadone-using study subjects. DESIGN A 24-hour methadone pharmacokinetic study was performed before antiretroviral therapy was begun and after 15 days of therapy. Methadone concentration was measured by a chiral plasma assay because the drug is administered as a racemic mixture of R- and S-methadone, but only the R-isomer is active. Both changes in plasma protein binding and changes in objective and subjective opioid effect were monitored. RESULTS Ritonavir/saquinavir administration was associated with 40% decrease in total S-methadone AUC0-24hr and 32% decrease in R-methadone area under the curve (AUC)0-24hr, and both changes were statistically significant (p =.001 for both). When AUC was corrected for the changes in protein binding induced by ritonavir/saquinavir, R-methadone free AUC0-24hr decreased 19.6% whereas the S-methadone decreased 24.6%, neither of these changes was statistically significant (p =.129 and p =.0537, respectively). This change in methadone exposure was not associated with any evidence of withdrawal from narcotics and no modification of methadone dose was required. CONCLUSIONS Our data indicate that ritonavir/saquinavir administration is associated with induction of metabolism of methadone but this is greater for the inactive S-methadone. However, approximately 37% of the decrease in the total R-methadone exposure can be explained by protein binding displacement. Ritonavir/saquinavir can be used in HIV-infected people taking methadone without routine dose adjustments.
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Patel HH, Hsu A, Gross GJ. Cardioprotection is strain dependent in rat in response to whole body hyperthermia. Am J Physiol Heart Circ Physiol 2001; 280:H1208-14. [PMID: 11179065 DOI: 10.1152/ajpheart.2001.280.3.h1208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous results showed a genetic component to cardioprotection. Therefore, we investigated the heat shock response in Wistar and Sprague-Dawley (SD) rats at 24 and 48 h. Rats were subjected to whole body hyperthermia achieving colonic temperatures of 40 or 42 degrees C for 20 min. After recovery hearts were excised for protein measurements or were subjected to 30 min of ischemia and then 2 h of reperfusion. Heat shock protein (HSP) expression was determined by Western blotting and infarct size was determined by triphenyltetrazolium staining. All groups of SD and Wistar rats demonstrated HSP72 and HSP90 induction at both time points in response to a heat stress of 42 degrees C. At 24 h there was only a significant reduction in infarct size seen in control vs. small SD (60.0 +/- 4.8 vs. 26.5 +/- 2.3) rats. However, at 48 h control versus small SD (60.0 +/- 4.8 vs. 17.6 +/- 3.8) and Wistar (59.4 +/- 4.3 vs. 29.8 +/- 6.0) and control versus large SD (53.7 +/- 2.6 vs. 19.8 +/- 4.7) and Wistar (57.3 +/- 1.6 vs. 34.5 +/- 2.8) rats demonstrated a significant reduction in infarct size with a greater reduction observed in SD rats. We conclude that heat shock-induced cardioprotection in rats is dependent on strain, temperature, time after stress, and size.
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Murphy RL, Brun S, Hicks C, Eron JJ, Gulick R, King M, White AC, Benson C, Thompson M, Kessler HA, Hammer S, Bertz R, Hsu A, Japour A, Sun E. ABT-378/ritonavir plus stavudine and lamivudine for the treatment of antiretroviral-naive adults with HIV-1 infection: 48-week results. AIDS 2001; 15:F1-9. [PMID: 11192874 DOI: 10.1097/00002030-200101050-00002] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To evaluate the safety and antiviral activity of different dose levels of the HIV protease inhibitor ABT-378 combined with low-dose ritonavir, plus stavudine and lamivudine in antiretroviral-naive individuals. DESIGN Prospective, randomized, double-blind, multicenter. METHODS Eligible patients with plasma HIV-1 RNA > 5000 copies/ml received ABT-378 200 or 400 mg with ritonavir 100 mg every 12 h; after 3 weeks stavudine 40 mg and lamivudine 150 mg every 12 h were added (group I, n = 32). A second group initiated treatment with ABT-378 400 mg and ritonavir 100 or 200 mg plus stavudine and lamivudine every 12 h (group II, n = 68). RESULTS Mean baseline HIV-1 RNA was 4.9 log10 copies/ml in both groups and CD4 cell count was 398 x 10(6)/l and 310 x 10(6)/l in Groups I and II respectively. In the intent-to-treat (ITT; missing value = failure) analysis at 48 weeks, HIV-1 RNA was < 400 copies/ml for 91% (< 50 copies/ml, 75%) and 82% (< 50 copies/ml, 79%) of patients in groups I and II respectively. Mean steady-state ABT-378 trough concentrations exceeded the wild-type HIV-1 EC50 (effective concentration to inhibit 50%) by 50-100-fold. The most common adverse events were abnormal stools, diarrhea and nausea. No patient discontinued before 48 weeks because of treatment-related toxicity or virologic rebound. CONCLUSIONS ABT-378 is a potent, well-tolerated protease inhibitor. The activity and durable suppression of HIV-1 observed in this study is probably attributable to the observed tolerability profile and the achievement of high ABT-378 plasma concentrations.
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Chotani G, Dodge T, Hsu A, Kumar M, LaDuca R, Trimbur D, Weyler W, Sanford K. The commercial production of chemicals using pathway engineering. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1543:434-455. [PMID: 11150618 DOI: 10.1016/s0167-4838(00)00234-x] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Integration of metabolic pathway engineering and fermentation production technologies is necessary for the successful commercial production of chemicals. The 'toolbox' to do pathway engineering is ever expanding to enable mining of biodiversity, to maximize productivity, enhance carbon efficiency, improve product purity, expand product lines, and broaden markets. Functional genomics, proteomics, fluxomics, and physiomics are complementary to pathway engineering, and their successful applications are bound to multiply product turnover per cell, channel carbon efficiently, shrink the size of factories (i.e., reduce steel in the ground), and minimize product development cycle times to bring products to market.
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Shashidharan P, Good PF, Hsu A, Perl DP, Brin MF, Olanow CW. TorsinA accumulation in Lewy bodies in sporadic Parkinson's disease. Brain Res 2000; 877:379-81. [PMID: 10986355 DOI: 10.1016/s0006-8993(00)02702-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Parkinson's disease (PD) is a neurodegnerative disorder that is pathologically characterized by the presence of Lewy bodies in the brain. We show that Lewy bodies in PD are strongly immunoreactive for torsinA, the protein product of the DYT1 gene, which is associated with primary generalized dystonia. In the substantia nigra, torsinA immunoreactivity is localized to the periphery of Lewy bodies, whereas, in cortical Lewy bodies it is uniformly distributed. The significance of this finding is unknown, but may implicate torsinA in neuronal dysfunction that occurs in PD as well as in primary dystonia.
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Kilani AF, Trang P, Jo S, Hsu A, Kim J, Nepomuceno E, Liou K, Liu F. RNase P ribozymes selected in vitro to cleave a viral mRNA effectively inhibit its expression in cell culture. J Biol Chem 2000; 275:10611-22. [PMID: 10744757 DOI: 10.1074/jbc.275.14.10611] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An in vitro selection procedure was used to select RNase P ribozyme variants that efficiently cleaved the sequence of the mRNA encoding thymidine kinase of herpes simplex virus 1. Of the 45 selected variants sequenced, 25 ribozymes carried a common mutation at nucleotides 224 and 225 of RNase P catalytic RNA from Escherichia coli (G(224)G(225) --> AA). These selected ribozymes exhibited at least 10 times higher cleavage efficiency (k(cat)/K(m)) than that derived from the wild type ribozyme. Our results suggest that the mutated A(224)A(225) are in close proximity to the substrate and enhance substrate binding of the ribozyme. When these ribozyme variants were expressed in herpes simplex virus 1-infected cells, the levels of thymidine kinase mRNA and protein were reduced by 95-99%. Our study provides the first direct evidence that RNase P ribozyme variants isolated by the selection procedure can be used for the construction of gene-targeting ribozymes that are highly effective in tissue culture. These results demonstrate the potential for using RNase P ribozymes as gene-targeting agents against any mRNA sequences, and using the selection procedure as a general approach for the engineering of RNase P ribozymes.
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MESH Headings
- Animals
- Base Sequence
- Clone Cells
- Endoribonucleases/chemistry
- Endoribonucleases/genetics
- Endoribonucleases/metabolism
- Escherichia coli Proteins
- Genetic Engineering
- Genetic Variation
- Herpesvirus 1, Human/enzymology
- Herpesvirus 1, Human/genetics
- Kinetics
- Molecular Sequence Data
- Mutagenesis
- Nucleic Acid Conformation
- Oligodeoxyribonucleotides
- RNA, Catalytic/chemistry
- RNA, Catalytic/genetics
- RNA, Catalytic/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Recombinant Proteins/metabolism
- Ribonuclease P
- Sequence Alignment
- Thymidine Kinase/genetics
- Transcription, Genetic
- Transfection
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Hsu A, Smith RG, Buchsbaum G, Sterling P. Cost of cone coupling to trichromacy in primate fovea. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2000; 17:635-640. [PMID: 10708045 DOI: 10.1364/josaa.17.000635] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cone synaptic terminals couple electrically to their neighbors. This reduces the amplitude of temporally uncorrelated voltage differences between neighbors. For an achromatic stimulus coarser than the cone mosaic, the uncorrelated voltage difference between neighbors represents mostly noise; so noise is reduced more than the signal. Here coupling improves signal-to-noise ratio and enhances contrast sensitivity. But for a chromatic stimulus the uncorrelated voltage difference between neighbors of different spectral type represents mostly signal; so signal would be reduced more than the noise. This cost of cone coupling to encoding chromatic signals was evaluated using a compartmental model of the foveal cone array. When cones sensitive to middle (M) and long (L) wavelengths alternated regularly, and the conductance between a cone and all of its immediate neighbors was 1,000 pS (approximately 2 connexons/cone pair), coupling reduced the difference between the L and M action spectra by nearly fivefold, from about 38% to 8%. However, L and M cones distribute randomly in the mosaic, forming small patches of like type, and within a patch the responses to a chromatic stimulus are correlated. In such a mosaic, coupling still reduced the difference between the L and M action spectra, but only by 2.4-fold, to about 18%. This result is independent of the L/M ratio. Thus "patchiness" of the L/M mosaic allows cone coupling to improve achromatic contrast sensitivity while minimizing the cost to chromatic sensitivity.
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123
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Tan EH, Wee J, Ang PT, Fong KW, Leong SS, Khoo KS, Tan T, Lee KS, Eng P, Hsu A, Tan YK, Chua EJ, Ong YY. Induction chemotherapy followed by concurrent chemoradiotherapy in stage III unresectable non-small cell lung cancer. Acta Oncol 2000; 38:1005-9. [PMID: 10665753 DOI: 10.1080/028418699432266] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The favourable experience with the combination regimen of vinorelbine, ifosfamide and cisplatin (NIP) in patients with metastatic non-small cell lung cancer (NSCLC) has led to a protocol assessing this regimen as an induction treatment in patients with stage III unresectable NSCLC, followed by thoracic radiotherapy with concurrent daily cisplatin as a radiosensitizer. Two cycles of NIP were administered 21 days apart; each cycle comprised i.v. vinorelbine 25 mg/m2 on days 1 and 8, i.v. ifosfamide 3 g/m2 on day 1 with MESNA as uroprotection, and i.v. cisplatin 50 mg/m2 on day 1. Radical thoracic radiotherapy commenced on day 43 to a total dose of 64 Gy and i.v. cisplatin 6 mg/m2 was given concurrently prior to each fraction of radiation as a sensitiser. Two more cycles of NIP were given to patients who responded favourably to the induction treatment about 2 weeks after completion of radiation. Between July 1995 and July 1997, 44 patients were treated with this protocol. This treatment schedule was generally well tolerated. Grade 3-4 neutropenia occurred in 50% of the patients and neutropenic sepsis was seen in 8. Grade 3-4 oesophagitis was uncommon. Most of the patients were able to complete the induction and concurrent chemoradiotherapy phase. Major response occurred in 75% of the patients with 2 (4.5%) complete responses (CR). A total of 6 patients achieved CR after chemoradiotherapy. At a median follow-up of 35 months, the median overall survival for all patients was 15 months with a 3-year survival rate of 24%. The median overall survival for stage IIIA patients was 19 months with a 3-year survival rate of 39% in contrast to 13 months' median overall survival and only 15% 3-year survival rate for stage IIIB. The NIP regimen results in a high response rate in NSCLC and this treatment programme seems to benefit selected patients with stage III disease.
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124
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van Heeswijk RP, Veldkamp AI, Hoetelmans RM, Mulder JW, Schreij G, Hsu A, Lange JM, Beijnen JH, Meenhorst PL. The steady-state plasma pharmacokinetics of indinavir alone and in combination with a low dose of ritonavir in twice daily dosing regimens in HIV-1-infected individuals. AIDS 1999; 13:F95-9. [PMID: 10513637 DOI: 10.1097/00002030-199910010-00001] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To explore the steady-state plasma pharmacokinetics of indinavir in twice daily dosing regimens with and without the co-administration of 100 mg ritonavir. DESIGN Observational pharmacokinetic study. PATIENTS HIV-1-infected individuals who use indinavir alone (1200 mg twice daily, n = 6), or the combination of 100 mg ritonavir twice daily plus either 800 mg (n = 6), or 1200 mg indinavir twice daily (n = 2). METHODS Steady-state pharmacokinetics of indinavir and ritonavir were assessed by drawing 12 blood samples during an 8-h period after ingestion of the medication. RESULTS Significant differences were observed for indinavir pharmacokinetics between the dosing regimens indinavir 1200 mg twice daily alone and indinavir/ ritonavir 800/100 mg twice daily with respect to the mean trough concentration (0.21 and 0.99 microg/ml, respectively, P = 0.002), the mean maximum concentration (13.79 and 8.74 microg/ml, respectively, P = 0.028), and for the mean plasma elimination half-life (1.6 and 3.2 h, respectively, P = 0.001). The combination indinavir/ritonavir 1200/100 mg twice daily led to very high exposure to indinavir and was not well tolerated. However, the combination indinavir/ritonavir 800/100 mg twice daily was well tolerated and resulted in therapeutic concentrations of indinavir with improved trough concentrations and similar maximum concentrations as observed with the licensed dosage of 800 mg three times daily. CONCLUSION Combination of indinavir and 100 mg ritonavir in twice daily dosing regimens significantly affects the pharmacokinetic profile of indinavir. The results of this observational study provide a pharmacologic basis for the combination of indinavir (800 mg) and ritonavir (100 mg) in twice daily dosing regimens.
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125
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See HT, Hsu A. A breathless lady with lumpy kidneys. Singapore Med J 1999; 40:477-9. [PMID: 10560275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Tuberous sclerosis complex (TSC) is now known to be associated with pulmonary lymphangiomyomatosis (PLAM). Patients with either isolated PLAM or pulmonary involvement in TSC suffer from progressive respiratory failure and death within ten years of diagnosis. We report a case of TSC with PLAM, and a short review of recent literature regarding the conditions.
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