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Tsang S, Holt AM, Azevedo E. An assessment of the barriers to accessing food among food-insecure people in Cobourg, Ontario. ACTA ACUST UNITED AC 2011. [DOI: 10.24095/hpcdp.31.3.06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Introduction
Low-income people are most vulnerable to food insecurity; many turn to community and/or charitable food programs to receive free or low-cost food. This needs assessment aims to collect information on the barriers to accessing food programs, the opportunities for improving food access, the barriers to eating fresh vegetables and fruit, and the opportunities to increasing their consumption among food-insecure people in Cobourg, Ontario.
Methods
We interviewed food program clients using structured individual interviews consisting of mostly opened-ended questions.
Results
Food program clients identified barriers to using food programs as lack of transportation and the food programs having insufficient quantities of food or inconvenient operating hours. They also stated a lack of available vegetables and fruit at home, and income as barriers to eating more vegetables and fruit, but suggested a local fresh fruit and vegetable bulk-buying program called “Good Food Box” and community gardens as opportunities to help increase their vegetable and fruit intake.
Discussion
Many of the barriers and opportunities identified can be addressed by working with community partners to help low-income individuals become more food secure.
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Tsang S, Holt AM, Azevedo E. An assessment of the barriers to accessing food among food-insecure people in Cobourg, Ontario. CHRONIC DISEASES AND INJURIES IN CANADA 2011; 31:121-128. [PMID: 21733349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
INTRODUCTION Low-income people are most vulnerable to food insecurity; many turn to community and/or charitable food programs to receive free or low-cost food. This needs assessment aims to collect information on the barriers to accessing food programs, the opportunities for improving food access, the barriers to eating fresh vegetables and fruit, and the opportunities to increasing their consumption among food-insecure people in Cobourg, Ontario. METHODS We interviewed food program clients using structured individual interviews consisting of mostly opened-ended questions. RESULTS Food program clients identified barriers to using food programs as lack of transportation and the food programs having insufficient quantities of food or inconvenient operating hours. They also stated a lack of available vegetables and fruit at home, and income as barriers to eating more vegetables and fruit, but suggested a local fresh fruit and vegetable bulk-buying program called "Good Food Box" and community gardens as opportunities to help increase their vegetable and fruit intake. DISCUSSION Many of the barriers and opportunities identified can be addressed by working with community partners to help low-income individuals become more food secure.
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Pun F, Zhao C, Lo W, Ng S, Tsang S, Nimgaonkar V, Chung W, Ungvari G, Xue H. Imprinting in the schizophrenia candidate gene GABRB2. Eur Psychiatry 2011. [DOI: 10.1016/s0924-9338(11)72528-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Imprinting, characterized by unequal expression of the offspring's genes in a parent-of-origin dependent manner, has been functionally implicated in brain development and in psychiatric disorders. In this study, unambiguous distortion in paternal but not maternal transmission of the disease-associated single-nucleotide polymorphism (SNP) rs6556547 (T/G) clearly indicated the presence of parent-of-origin effect (POE) in the GABAA receptor β2 subunit gene (GABRB2). ‘Flipping’ of allelic mRNA expression in heterozygotes of SNP rs2229944 (C/T) and the observed two-tiered distribution of mRNA expression levels in heterozygotes of the disease-associated SNP rs1816071 (G/A) furnished important support for the occurrence of imprinting at GABRB2. Imprinting in effect introduced heterozygotes from different parents-of-origin endowed with dissimilar mRNA expression capabilities. The deficit of upper-tiered expressions accounted for the lowered mRNA expression levels in the schizophrenic heterozygotes. This pointed to the necessity of differentiating between two kinds of heterozygotes of different parental origins in disease association studies on GABRB2. Bisulfite sequencing revealed hypermethylation in the neighborhood of SNP rs1816071, and methylation differences between controls and schizophrenia patients. Notably, allele-specific methylation was observed at the disease-associated SNPs rs6556547 and rs1816071. These findings raised the possibility that CpG methylation status of these sites could have an impact on the expression of GABRB2 and the risk of schizophrenia. Furthermore, the occurrence of imprinting and allele-specific methylation in the schizophrenia candidate gene GABRB2 was compatible with the epigenetic hypothesis for schizophrenia pathophysiology, thereby calling for the need to explore the role of epigenetic factors in mediating susceptibility to schizophrenia.
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Doolittle RF, Feng DF, Tsang S, Cho G, Little E. Response: dating the cenancester of organisms. Science 2010; 274:1751-3. [PMID: 17842248 DOI: 10.1126/science.274.5293.1751] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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480
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Morley L, Tsang S, Bayley A, Cho J, Cummings B, Dawson L, Hope A, O'Sullivan B, Ringash J, Waldron J, Breen S, Kim J. 195 EVALUATION OF INFRA-HYOID MIDLINE NORMAL STRUCTURE DOSES IN OROPHARYNX SQUAMOUS CELL CANCER TREATED WITH IMRT. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(12)72582-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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481
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Stork LC, Buchanan N, Maloney K, Tsang S, Neglia JP, Kadan-Lottick NS. Impairments in social and adaptive functioning one month after diagnosis in children with standard risk ALL on COG AALL0331. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.10034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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482
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Buchanan N, Maloney K, Tsang S, Stork LC, Neglia JP, Kadan-Lottick NS. Risk of depression, anxiety, and somatization one month after diagnosis in children with standard risk ALL on COG AALL0331. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.10052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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483
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Tsang S, Wu S, Liu J, Wong TM. Testosterone protects rat hearts against ischaemic insults by enhancing the effects of alpha(1)-adrenoceptor stimulation. Br J Pharmacol 2007; 153:693-709. [PMID: 18157169 DOI: 10.1038/sj.bjp.0707624] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Testosterone alleviates symptoms in patients with ischaemic heart disease. Androgen receptors are present in the heart, and testosterone upregulates gene expression of cardiac beta(1)-adrenoceptors. We hypothesize that testosterone may confer cardioprotection by interacting with adrenoceptors. EXPERIMENTAL APPROACH In isolated perfused hearts and ventricular myocytes from orchidectomized rats without or with testosterone (200 microg/100 g) replacement, we first determined the effect of ischaemia/reperfusion in the presence of noradrenaline (10(-7) M). Then we determined the contribution of interactions between testosterone and alpha(1)- or beta(1)-adrenoceptors in cardiac injury/protection (infarct size, release of lactate dehydrogenase, viability of myocytes, recovery of contractile function and incidence of arrhythmias) upon ischaemia/reperfusion by pharmacological manipulation using selective adrenoceptor agonists (alpha(1)-adrenoceptor agonist: phenylephrine 10(-6) M; non-selective beta-adrenoceptor agonist: isoprenaline 10(-7) M) and antagonists (alpha(1): prazosin or benoxathian 10(-6) M; beta(1): CGP 20712A 5 x 10(-7) M). We also determined the expression of alpha(1) and beta(1)-adrenoceptor in the hearts from rats with and without testosterone. KEY RESULTS Testosterone reduced injury induced by ischaemia/reperfusion and noradrenaline. This was achieved by enhancing the beneficial effect of alpha(1)-adrenoceptor stimulation, which was greater than the deleterious effect of beta(1)-adrenoceptor stimulation (also enhanced by testosterone). The effects of testosterone were abolished or attenuated by blockade of androgen receptors. Testosterone also enhanced the expression of alpha(1A) and beta(1)-adrenoceptor. CONCLUSIONS AND IMPLICATIONS Testosterone conferred cardioprotection by upregulating the cardiac alpha(1)-adrenoceptor and enhancing the effects of stimulation of this adrenoceptor. The effect of testosterone was at least partly mediated by androgen receptors.
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484
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Vu C, Tsang S, Doig L, Meenan J. The preferred choice for radial endosonographic staging of esophageal cancer: standard echoendoscope or nonoptic esophagoprobe? Surg Endosc 2007; 21:1617-22. [PMID: 17342557 DOI: 10.1007/s00464-007-9206-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Accepted: 12/12/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND The nonoptic esophagoprobe has been reported to be comparable to the standard echoendoscope in esophageal cancer staging, with a superior advantage of traversing more stenotic tumors because of its smaller diameter. The aim of this study was to see whether its use in a general population of esophageal cancer patients confers any significant clinical benefit. METHODS Five hundred seventy-seven consecutive patients referred for initial locoregional staging of esophageal cancer were analyzed retrospectively. Comparisons were made between the standard echoendoscope and the esophagoprobe. RESULTS Complete staging (95.2% vs 77.5%; p < 0.001) was significantly higher in the esophagoprobe group compared with that of the standard echoendoscope group (315 and 262 patients, respectively). In 146 patients with histopathologic verification without prior chemotherapy or radiotherapy, the esophagoprobe was comparable in T-staging accuracy to the standard echoendoscope in those with traversable tumors (89.2% vs. 82.8%; p = 0.213). However, the presence of a nontraversable stricture significantly decreased standard echoendoscope T-staging accuracy compared with a traversable stricture (33.3% vs. 82.8%, respectively; p < 0.001). The esophagoprobe also picked more advanced tumors and distal nodes. CONCLUSIONS The esophagoprobe is more accurate than the standard echoendoscope in the T staging of esophageal cancer because of its higher likelihood of traversing tumor stenosis. It can potentially reduce the necessity for dilation in stenotic tumors by four to five times. We propose using the esophagoprobe as the first choice for radial endoscopic ultrasound staging of esophageal cancer.
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485
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Knosalla C, Clark AL, Birks E, Loebe M, Davos CH, Tsang S, Yacoub M, Hetzer R, Coats AJ, Anker SD. Heart transplantation in heart failure: the prognostic importance of body mass index at time of surgery and subsequent weight changes. Thorac Cardiovasc Surg 2007. [DOI: 10.1055/s-2007-967486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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486
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Chan H, Wong V, Hui A, Tsang S, Chan J, Wong G, Sung J. P.121 Severe acute exacerbation of HBeAg-negative chronic hepatitis B has good maintained response to lamivudine treatment. J Clin Virol 2006. [DOI: 10.1016/s1386-6532(06)80301-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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487
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Mathews BW, Carpenter JR, Sollenberger LE, Tsang S. Phosphorus in Hawaiian kikuyugrass pastures and potential phosphorus release to water. JOURNAL OF ENVIRONMENTAL QUALITY 2005; 34:1214-23. [PMID: 15942040 DOI: 10.2134/jeq2004.0393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Pasture systems in Hawaii are based primarily on kikuyugrass (Pennisetum clandestinum Hochst. ex Chiov.). Relationships among kikuyugrass P concentration, animal P requirements, and various soil P determinations are needed to help identify source areas for implementing pasture management strategies to limit P loss via overland flow. A total of 51 rotationally stocked kikuyugrass pastures (>20 yr old) with contrasting soil chemical properties were sampled. A satisfactory predictive relationship between modified-Truog (MT)-extractable phosphorus (P(MT)) and dissolved (<0.45-mum pore diameter), molybdate-reactive phosphorus (DRP) desorbed from soil in a water extract (DRP(WE)) was found when 0- to 4-cm-depth data for the soil orders with medium to high DRP(WE) (two Mollisols and an Inceptisol) were pooled separately from those with low DRP(WE) (five Andisols, three Ultisols, and an Oxisol). The oxalate phosphorus saturation index (PSI(ox)) procedure was the best predictor of DRP(WE) across soil orders when oxalate-extractable molybdate-reactive phosphorus (RP(ox)) was used to calculate PSI(ox) (PSI(ox)RP) rather than when total oxalate-extractable phosphorus (TP(ox)) was used (PSI(ox)TP). There was little DRP(WE) until PSI(ox)RP exceeded 6% or PSI(ox)TP exceeded 8%. A more empirical dilute-acid phosphorus saturation index (PSI(MT)) was also calculated using P(MT) and MT-extractable iron (Fe(MT)) and aluminum (Al(MT)). The PSI(MT) procedure showed some utility in predicting DRP(WE), was positively related to the PSI(ox) procedures, and can be more readily performed in agronomic soil testing laboratories than PSI(ox). The present research suggests that while Hawaiian kikuyugrass pastures tend to be sufficient to high in forage P, potential soil P release to water only appeared to be a possible environmental concern for the Mollisol and Inceptisol sites.
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Landi MT, Goldstein AM, Tsang S, Munroe D, Modi W, Ter-Minassian M, Steighner R, Dean M, Metheny N, Staats B, Agatep R, Hogg D, Calista D. Genetic susceptibility in familial melanoma from northeastern Italy. J Med Genet 2004; 41:557-66. [PMID: 15235029 PMCID: PMC1735833 DOI: 10.1136/jmg.2003.016907] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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489
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Meenan J, Anderson S, Tsang S, Reffitt D, Prasad P, Doig L. Training in radial EUS: what is the best approach and is there a role for the nurse endoscopist? Endoscopy 2003; 35:1020-3. [PMID: 14648414 DOI: 10.1055/s-2003-44587] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND STUDY AIMS The aim of this study was to determine the relative contribution of previous endoscopic experience, case observation, and hands-on experience to skill acquisition in radial EUS. METHODS In EUS trainees, four senior gastroenterology fellows, and a nurse endoscopist, the ability to reproduce set views from the mediastinum, stomach, and duodenum was assessed. Points were ascribed to static and dynamic stations and to the use of console controls. RESULTS Trainees observed 55 - 170 cases and conducted 25 - 124 examinations. Competence was demonstrated after performing approximately 25 examinations in the mediastinum, 35 examinations in the stomach, and 78 examinations in the duodenum. The number of previous examinations conducted correlated with the ability to scan the duodenum ( P < 0.01). Observation of 100 or more further procedures early in training did not accelerate learning. The nurse endoscopist showed a comparable degree of competence in mediastinal scanning to that of the other trainees after performing a similar number of examinations. CONCLUSIONS Proficiency in radial endosonography is greatly influenced by the numbers of examinations performed. Observing large numbers of cases early in training does not appear to translate into competence. A background in advanced therapeutic endoscopy is not a prerequisite for acquiring endoscopic ultrasound skills. Nurse endoscopists may be expected to train successfully in mediastinal imaging at the same pace as senior gastroenterology fellows.
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490
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Baden LR, Katz JT, Franck L, Tsang S, Hall M, Rubin RH, Jarcho J. Successful toxoplasmosis prophylaxis after orthotopic cardiac transplantation with trimethoprim-sulfamethoxazole. Transplantation 2003; 75:339-43. [PMID: 12589155 DOI: 10.1097/01.tp.0000044864.99398.f1] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The efficacy of trimethoprim-sulfamethoxazole (TMP/SMX) in the prevention of toxoplasmosis after orthotopic cardiac transplantation has been the subject of some controversy, with many transplant groups preferring to use the combination of pyrimethamine and sulfadiazine. Although effective, this latter regimen does not offer equal protection against other pathogens, such as or. To assess the value of TMP/SMX, we reviewed the experience in our heart transplant patients, all of whom received TMP/SMX (160/800 mg) three times weekly for approximately 8 months after transplantation. METHODS We report on 417 orthotopic cardiac transplants during a 17-year period. We have 100% one-year patient follow-up after transplantation. Data was collected on pretransplantation donor and recipient anti- serology, immunosuppression, allograft rejection, survival, yearly posttransplantation anti- serology, development of acute toxoplasmosis, and the occurrence of other infections. RESULTS In this cohort, acute toxoplasmosis developed after transplantation in one case (0.2%). Among the highest risk patients (D+R-) who were treated for at least one episode of rejection, the risk of acute toxoplasmosis was 5% (1 of 22 patients). No change in survival was found between the different anti- IgG serogroups (D-R-, D-R+, D+R-, or D+R+). Anti- IgG seroconversion occurred in eight -seronegative recipients after transplantation; all patients, except the case already noted, were asymptomatic and required no specific anti- therapy. No cases of, or infections were identified. Five proven and two suspected cases of pneumonia were found (only 2 of these 7 patients were receiving TMP/SMX at the time of pneumonia diagnosis). CONCLUSIONS These data demonstrate that TMP/SMX prophylaxis (160/800 mg) three times per week is effective prophylaxis after orthotopic cardiac transplantation and has prophylactic benefits against other posttransplantation opportunistic pathogens.
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491
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Ju H, Gros R, You X, Tsang S, Husain M, Rabinovitch M. Conditional and targeted overexpression of vascular chymase causes hypertension in transgenic mice. Proc Natl Acad Sci U S A 2001; 98:7469-74. [PMID: 11416217 PMCID: PMC34692 DOI: 10.1073/pnas.131147598] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We cloned a rat vascular chymase (RVCH) from smooth muscle cells (SMCs) that converts angiotensin I to II and is up-regulated in SMC from spontaneously hypertensive vs. normotensive rats. To determine whether increased activity of RVCH is sufficient to cause hypertension, transgenic mice were generated with targeted conditional expression of RVCH to SMC, with the use of the tetracycline-controlled transactivator (tTA). We confirmed conditional expression of RVCH by mRNA, protein, and chymase activity in the absence, but not in the presence, of dietary doxycycline. The systolic blood pressure (mmHg), measured by carotid artery cannulation at 10-12 weeks of age, was higher in tTA+/RVCH+ mice than in nonbinary transgenic littermates (136 +/- 4 vs. 109 +/- 3) (P < 0.05), as were the diastolic and mean pressures. Hypertension was completely reversed by doxycycline, suggesting a causal link with chymase expression. Medial thickening of mesenteric arteries from tTA+/RVCH+ mice vs. littermates (0.82 +/- 0.1 vs. 0.42 +/- 0.02) (P < 0.05) was associated with increased SMC proliferation, as judged by positive immunoreactivity, with the use of an antibody to the proliferating cell nuclear antigen. These structural changes were prevented by doxycycline. Perfusion myography of mesenteric arteries from tTA+/RVCH+ mice also revealed increased vasoconstriction in response to phenylephrine and impaired metacholine-induced vasodilatation when compared with littermate controls or with the doxycyline-treated group. Our studies suggest that up-regulation of this vascular chymase is sufficient to cause a hypertensive arteriopathy, and that RVCH may be a candidate gene and a therapeutic target in patients with high blood pressure.
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492
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Li AS, Bandy B, Tsang S, Davison AJ. DNA breakage induced by 1,2,4-benzenetriol: relative contributions of oxygen-derived active species and transition metal ions. Free Radic Biol Med 2001; 30:943-56. [PMID: 11316574 DOI: 10.1016/s0891-5849(01)00478-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report here the relative roles of metals and selected reactive oxygen species in DNA damage by the genotoxic benzene metabolite 1,2,4-benzenetriol, and the interactions of antioxidants in affording protection. 1,2,4-Benzenetriol induces scission in supercoiled phage DNA in neutral aqueous solution with an effective dose (ED(50)) of 6.7 microM for 50% cleavage of 2.05 microg/ml supercoiled PM2 DNA. In decreasing order of effectiveness: catalase (20 U/ml), formate (25 mM), superoxide dismutase (20 U/ml), and mannitol (50 mM) protected, from 85 to 28%. Evidently, H(2)O(2) is the dominant active species, with O(2)(*)(-) and *OH playing subordinate roles. Desferrioxamine or EDTA inhibited DNA breakage by 81-85%, despite accelerating 1,2,4-benzenetriol autoxidation. Consistent with this suggestion of a crucial role for metals, addition of cupric, cuprous, ferric, or ferrous ions enhanced DNA breakage, with copper being more active than iron. Combinations of scavengers protected more effectively than any single scavenger alone, with implications for antioxidants acting in concert in living cells. Synergistic combinations were superoxide dismutase with *OH scavengers, superoxide dismutase with desferrioxamine, and catalase with desferrioxamine. Antagonistic (preemptive) combinations were catalase with superoxide dismutase, desferrioxamine with *OH scavengers, and catalase with *OH scavengers. The most striking aspect of synergism was the extent to which metal chelation (desferrioxamine) acted synergistically with either catalase or superoxide dismutase to provide virtually complete protection. Concluding, 1,2,4-benzenetriol-induced DNA damage occurs mainly by site-specific, Fenton-type mechanisms, involving synergism between several reactive intermediates. Multiple antioxidant actions are needed for effective protection.
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493
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Kleiber J, Walter T, Haberhausen G, Tsang S, Babiel R, Rosenstraus M. Performance characteristics of a quantitative, homogeneous TaqMan RT-PCR test for HCV RNA. J Mol Diagn 2000; 2:158-66. [PMID: 11229521 PMCID: PMC1906908 DOI: 10.1016/s1525-1578(10)60632-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We developed a homogeneous format reverse transcription-polymerase chain reaction assay for quantitating hepatitis C virus (HCV) RNA based on the TaqMan principle, in which signal is generated by cleaving a target-specific probe during amplification. The test uses two probes, one specific for HCV and one specific for an internal control, containing fluorophores with different emission spectra. Titers are calculated in international units (IU)/ml by comparing the HCV signal generated by test samples to that generated by a set of external standards. Endpoint titration experiments demonstrated that samples containing 28 IU/ml give positive results 95% of the time. Based on these data, the limit of detection was set conservatively at 40 IU/ml. All HCV genotypes were amplified with equal efficiency and accurately quantitated: when equal quantities of RNA were tested, each genotype produced virtually identical fluorescent signals. The test exhibited a linear range extending from 64 to 4,180,000 IU/ml and excellent reproducibility, with coefficients of variation ranging from 21.6 to 30.4%, which implies that titers that differ by a factor of twofold (0.3 log10) are statistically significant (P = 0.005). The test did not react with other organisms likely to co-infect patients with hepatitis C and exhibited a specificity of 99% when evaluated on a set of samples from HCV seronegative blood donors. In interferon-treated patients, the patterns of viral load changes revealed by the TaqMan HCV quantitative test distinguished responders from nonresponders and responder-relapsers. These data indicate that the TaqMan quantitative HCV test provides an attractive alternative for measuring HCV viral load and should prove useful for prognosis and for monitoring the efficacy of antiviral treatments.
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494
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Tang SG, See LC, Chen WC, Tsang S, Chang JT, Hong JH. The effect of nodal status on determinants of initial treatment response and patterns of relapse-free survival in nasopharyngeal carcinoma. Int J Radiat Oncol Biol Phys 2000; 47:867-73. [PMID: 10863054 DOI: 10.1016/s0360-3016(00)00490-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To study the effect of regional nodal status on predictors of treatment response, failure patterns, and the time-dependent nature of the various pattern of relapse via a hazard function analysis. METHODS AND MATERIALS We reviews tumor control data of 496 patients with nasopharyngeal carcinoma (NPC) to whom a radical course of radiotherapy (RT) with or without induction chemotherapy (CT) was given. All alive patients had a median follow-up period of 131 months. Primary tumor (T) and nodal (N) status were staged according to the TNM system of the American Joint Committee. Remote after-loading brachytherapy may be added to teletherapy in T1-2 lesions while induction CT could be given for N3 and/or T4 lesions. Hazard function analysis over 1-year interval was carried out for locoregional or distant relapse. RESULTS T stage and brachytherapy were two independent predictors for complete response (CR) at the primary site irrespective of nodal status, whereas N stage and brachytherapy are major determinants for regional CR in node (+) patients. Multivariate analysis revealed that contributors to a relatively long disease-free interval in (1) node (-) patients were for locoregional relapse, induction CT(-) (p = 0.0062) or brachytherapy (+) (p = 0.0268) and for distant relapse, none; (2) node (+) patients were for locoregional relapse, early T stage (p = 0.0377) or regional CR (p = 0.0075) and for distant relapse, induction CT(-) (p = 0.0001) or regional CR (p = 0.0001). In node (-) or (+) patients, primary CR rate yield no independent prognostic value on various types of disease-free survival. Hazard function analysis for relapse revealed that hazard rates are in general negatively correlated with time, being highest at the first year post-treatment, decreasing from time to time, and approaching zero after a longer follow-up period in patients with locoregional CR than in patients without. CONCLUSION Nodal status had no significant impact on predictors of primary CR, whereas in node (+) patients regional CR rate had an independent value in predicting disease-free survival to locoregional and distant relapse. Hazard function analysis revealed a decreasing hazard rate over a protracted post-treatment time in primary and regional CR patients. This indicates the continued risk of late recurrence in this subset of patients for whom long-term observation is recommended.
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495
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Tong TY, Goh VH, Tain CF, Mok H, Tsang S. Direct effects of varying doses of oestradiol on early embryonic development in in vitro culture of rat's two-cell embryos. Can J Physiol Pharmacol 2000; 78:453-6. [PMID: 10914633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Hyperstimulation in the rat using pregnant mares' serum gonadotrophin (PMSG) has been known to cause death in pre-implantation embryos, as well as enhancement of oestradiol production. This study examines the effect of oestradiol, in levels that are found in hyperstimulated pregnant rats, on pre-implantation embryonic development. Using a simplified in vitro system, 2-cell embryos retrieved from rats on the 2nd day of pregnancy were cultured in rat two-cell embryo culture medium (R2ECM) containing pharmacological doses of oestradiol for 96 h and scored daily in the morning. Three ngxmL(-1) oestradiol reduced the incidence of >8-cell embryos to morulae on the 5th day and blastocysts on the 6th day of development. Most embryos were retarded at the lower cell stages on the 5th day and degenerated by the 6th day. None of the blastocysts expanded on the last day of culture. Fifteen ngxmL(-1) oestradiol accelerated embryo development on the 3rd day but retarded development on the 4th day, and increased the incidence of degenerated embryos by the 5th and 6th day of development. These results suggest that the elevated oestradiol may constitute a mechanism by which PMSG induces death in pre-implantation rat embryos, possibly via a direct action on the embryos.
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496
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Tsang S, Hayashi M, Zheng X, Campbell A, Schellenberg RR. Simplified purification of human basophils. J Immunol Methods 2000; 233:13-20. [PMID: 10648851 DOI: 10.1016/s0022-1759(99)00182-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studies of human basophils have been limited by the low number present in peripheral blood and the difficulties of purification to homogeneity with reasonable yield and functional status. Reproducible purification of human basophils to 96.5+/-0.5% with a yield of 40.8+/-5.3% was obtained by negative selection using immunomagnetic beads following initial separation by density gradient centrifugation. Isolated cells demonstrated complete viability by vital dye exclusion and spontaneous histamine release following incubation of <5%. Stimulation with anti-IgE or calcium ionophore A23187 caused histamine release and leukotriene C(4) production. Basophils demonstrated dose-dependent chemotaxis to monocyte chemotactic protein-3. This simplified methodology results in fully functional basophils in very high purity and good yield.
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497
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Tang S, Chang T, Tsang S, Hong J, Liang W. Temporal relationship between serologic Epstein-Barr (EB) viral antibodies and treatment outcome in nasopharyngeal carcinoma. Eur J Cancer 1999. [DOI: 10.1016/s0959-8049(99)81049-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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498
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Hayashi M, Schellenberg RR, Tsang S, Roberts CR. Matrix metalloproteinase-9 in myeloid cells: implications for allergic inflammation. Int Arch Allergy Immunol 1999; 118:429-32. [PMID: 10224466 DOI: 10.1159/000024155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Matrix metalloproteinase-9 (MMP-9; 92 kDa gelatinase) is utilized by myeloid and lymphoid cells for migration across basement membranes. Although eosinophils are commonly seen infiltrating asthmatic airways, the role of basophils in allergic inflammation is debated. This study was undertaken to evaluate the content of MMP-9 in purified basophils compared with eosinophils and neutrophils. Peripheral blood basophils were isolated to greater than 95% purity using negative selection with antibody-coated magnetic beads using a 12-antibody cocktail. Eosinophils of greater than 98% purity were obtained by negative selection and neutrophils by positive selection using anti-CD16 magnetic beads. MMP-9 activity was assessed by gelatin zymography of cell lysates. Under parallel conditions, neutrophils contained 1,000-fold more MMP-9 than eosinophils. No activity was detected from 2x10(5) basophils. Immunocytochemistry with an anti-MMP-9 antibody showed bright staining of all neutrophils, lesser staining of eosinophils and no detectable staining of basophils. The failure to find MMP-9 in basophils may explain their paucity in asthmatic airway inflammation or suggest they secrete other enzymes capable of degrading type IV collagen.
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499
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Türeci O, Chen YT, Sahin U, Güre AO, Zwick C, Villena C, Tsang S, Seitz G, Old LJ, Pfreundschuh M. Expression of SSX genes in human tumors. Int J Cancer 1998. [PMID: 9639388 DOI: 10.1002/(sici)1097-0215(19980703)77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The HOM-MEL-40 antigen which is encoded by the SSX-2 gene was originally detected as a tumor antigen recognized by autologous IgG antibodies in a melanoma patient. Expression analysis demonstrated that SSX-2 is a member of the recently described cancer/testis antigen (CTA) class as it is expressed in a variety of different human neoplasms, but not in normal tissues with the exception of testis and a weak expression in the thyroid. Further studies demonstrated that SSX-2 belongs to a gene family consisting of at least 5 homologous genes. We now report the analysis of the expression of all 5 SSX genes in 325 specimens of human neoplasms from various histological origins, using reverse transcription polymerase chain reaction (RT-PCR). SSX-1, -2, and -4 were found to be expressed in 8%, 15% and 15%, of the tumors, respectively, while the expression of the SSX-5 gene was rare (7/325), and SSX-3 expression was not detected. For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.
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500
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Türeci O, Chen YT, Sahin U, Güre AO, Zwick C, Villena C, Tsang S, Seitz G, Old LJ, Pfreundschuh M. Expression of SSX genes in human tumors. Int J Cancer 1998. [PMID: 9639388 DOI: 10.1002/(sici)1097-0215(19980703)77:1<19::aid-ijc4>3.0.co;2-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The HOM-MEL-40 antigen which is encoded by the SSX-2 gene was originally detected as a tumor antigen recognized by autologous IgG antibodies in a melanoma patient. Expression analysis demonstrated that SSX-2 is a member of the recently described cancer/testis antigen (CTA) class as it is expressed in a variety of different human neoplasms, but not in normal tissues with the exception of testis and a weak expression in the thyroid. Further studies demonstrated that SSX-2 belongs to a gene family consisting of at least 5 homologous genes. We now report the analysis of the expression of all 5 SSX genes in 325 specimens of human neoplasms from various histological origins, using reverse transcription polymerase chain reaction (RT-PCR). SSX-1, -2, and -4 were found to be expressed in 8%, 15% and 15%, of the tumors, respectively, while the expression of the SSX-5 gene was rare (7/325), and SSX-3 expression was not detected. For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.
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