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Wong RW, Chan SY. Epidermal growth factor receptor: a transcription factor? Trends Biochem Sci 2001; 26:645-6. [PMID: 11701312 DOI: 10.1016/s0968-0004(01)02009-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Vaddi HK, Wang LZ, Ho PC, Chan YW, Chan SY. Effect of cetrimide and ascorbic acid on in vitro human skin permeation of haloperidol. Chem Pharm Bull (Tokyo) 2001; 49:1395-400. [PMID: 11724228 DOI: 10.1248/cpb.49.1395] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Permeation of haloperidol through the human skin in vitro was studied with two enhancers, cetrimide and ascorbic acid, at various concentrations. Amber glass Franz-type diffusion cells were used for the permeation studies and haloperidol was made soluble in aqueous solution with the aid of lactic acid. Donor solutions were prepared by adding excess of haloperidol to 0.03% (v/v) lactic acid solution with or without enhancers at concentrations 0.1, 0.3 and 0.6% (w/v) and stirred for 36 h at 32 degrees C before filtering. Ascorbic acid gradually increased the solubility of the haloperidol from that of the control where as cetrimide did not show any effect. Cetrimide concentration dependent increase in the permeability coefficient of haloperidol was observed. Mechanism of enhancement by cetrimide was probed with the diffusion profile kinetics and Fourier transform infrared (FT-IR) spectroscopy. Cetrimide was found to increase the thermodynamic activity of the drug in the skin. IR spectra of the stratum corneum treated with cetrimide showed time-dependent decrease in the intensity of the spectrum and dose-dependent decrease of lipid band but no change in the protein conformation. Cetrimide appears to interact with both the dermal keratin and lipids and this interaction was found to be irreversible. Ascorbic acid although increased the flux of haloperidol to the same extent at all concentrations from that of the control, decreased the permeability coefficient and enhancer index in a concentration dependent manner and this is due to the increased solubility of the drug in the vehicle. Both the enhancers did not change the lag time from that of the control.
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Phan TT, See P, Lee ST, Chan SY. Protective effects of curcumin against oxidative damage on skin cells in vitro: its implication for wound healing. THE JOURNAL OF TRAUMA 2001; 51:927-31. [PMID: 11706342 DOI: 10.1097/00005373-200111000-00017] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Curcumin, isolated from turmeric, has been known to possess many pharmacologic properties. It has been proven to exhibit remarkable anticarcinogenic, anti-inflammatory, and antioxidant properties. Turmeric curcumin may be a good potential agent for wound healing. METHODS To further understand its therapeutic mechanisms on wound healing, the antioxidant effects of curcumin on hydrogen peroxide (H2O2) and hypoxanthine-xanthine oxidase induced damage to cultured human keratinocytes and fibroblasts were investigated. Cell viability was assessed by colorimetric assay and quantification of lactate dehydrogenase release. RESULTS Exposure of human keratinocytes to curcumin at 10 microg/mL showed significant protective effect against hydrogen peroxide. Interestingly, exposure of human dermal fibroblasts to curcumin at 2.5 microg/mL showed significant protective effects against hydrogen peroxide. No protective effects of curcumin on either fibroblasts or keratinocytes against hypoxanthine-xanthine oxidase induced damage were found in our present studies. CONCLUSION The findings indicate that curcumin indeed possessed powerful inhibition against hydrogen peroxide damage in human keratinocytes and fibroblasts.
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Ma SK, Wan TS, Cheuk AT, Fung LF, Chan GC, Chan SY, Ha SY, Chan LC. Characterization of additional genetic events in childhood acute lymphoblastic leukemia with TEL/AML1 gene fusion: a molecular cytogenetics study. Leukemia 2001; 15:1442-7. [PMID: 11516105 DOI: 10.1038/sj.leu.2402202] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2000] [Accepted: 05/02/2001] [Indexed: 11/09/2022]
Abstract
TEL/AML1 gene fusion that results from a cryptic t(12;21) is the most common genetic aberration in childhood B-lineage acute lymphoblastic leukemia (ALL). While the translocation may initiate the leukemic process, critical secondary genetic events are currently believed to be pivotal for leukemogenesis. We investigated 12 cases of childhood ALL with TEL/AML1 gene fusion by fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) and documented additional or secondary genetic changes in seven patients (58%). Three patients showed extra copies of chromosome 21 including a case in which the trisomy 21 (+21) clone was distinct from the one harboring TEL/AML1 gene fusion. Interestingly, one patient without +21 showed amplification of the AML1 gene on chromosome 21q, supporting the contention that AML1 amplification may be an important additional genetic event. Gene expression study by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) in two of these four patients showed an increase in AML1 transcripts that paralleled the increase in gene copy number. Deletion of the normal TEL allele was detected in two patients, with one of them showing loss of chromosome 12 together with duplication of the der(12)t(12;21). Finally, one patient showed duplication of the fusion signal. Our findings confirm that additional or secondary genetic changes including AML1 amplification are commonly encountered in childhood ALL with TEL/AML1 gene fusion, which are envisaged to play significant roles in disease progression.
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Chan SY, Empig CJ, Welte FJ, Speck RF, Schmaljohn A, Kreisberg JF, Goldsmith MA. Folate receptor-alpha is a cofactor for cellular entry by Marburg and Ebola viruses. Cell 2001; 106:117-26. [PMID: 11461707 DOI: 10.1016/s0092-8674(01)00418-4] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human infections by Marburg (MBG) and Ebola (EBO) viruses result in lethal hemorrhagic fever. To identify cellular entry factors employed by MBG virus, noninfectible cells transduced with an expression library were challenged with a selectable pseudotype virus packaged by MBG glycoproteins (GP). A cDNA encoding the folate receptor-alpha (FR-alpha) was recovered from cells exhibiting reconstitution of viral entry. A FR-alpha cDNA was recovered in a similar strategy employing EBO pseudotypes. FR-alpha expression in Jurkat cells facilitated MBG or EBO entry, and FR-blocking reagents inhibited infection by MBG or EBO. Finally, FR-alpha bound cells expressing MBG or EBO GP and mediated syncytia formation triggered by MBG GP. Thus, FR-alpha is a significant cofactor for cellular entry for MBG and EBO viruses.
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Chan SY, Berry MG, Engledow AH, Perry NM, Wells CA, Carpenter R. Audit of a one-stop breast clinic--revisited. Breast Cancer 2001; 7:191-4. [PMID: 11029797 DOI: 10.1007/bf02967459] [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: 10/21/2022]
Abstract
BACKGROUND A one-stop diagnostic service has been available for women with symptomatic breast disease at St Bartholomew's Hospital for 5 years and was originally audited in May 1993. In re-auditing the one-stop service our aim was to see if our practice had improved following the original audit and to look at the impact which these changes in practice had made to the service offered to the patient. METHODS A prospective audit of 4 consecutive clinics was undertaken in November 1997. A total of 300 patients (59 new and 241 follow up) were seen in clinic in this time. The primary outcome measure concerned the completeness of triple assessment in the 40 patients who required one stop investigations, including mammography, ultrasonography and fine-needle aspiration cytology. In addition, mean time to initial consultation and level of awareness of the one-stop facility and its attendant time delay were measured. RESULTS Of the 300 clinic attendees 40 (38 new, 2 follow-up) had one-stop investigations. As a result of the one-stop service being in practice, 36 patients (90%) had a definitive management decision made at their first outpatient visit. Of these 2 were symptomatic cancers, forming 5% of the workload. A total of 86% of the workload was benign. Four patients (10%) had equivocal results. The mean waiting time from designated appointment until surgical consultation was 36.7 minutes and was disappointingly unchanged from that of the previous audit. However this does not take into account the significant reduction in staffing levels which has occurred between the two periods of assessment. CONCLUSIONS The initial audit identified a significant problem with time constraints, necessitating that a large number of patients with carcinomas return at a later date for further investigations. Booking only new patients at the beginning of clinic has provided a solution. Disappointingly, our figures do not show a significant improvement in mean waiting time compared with the previous audit, despite allowing GPs greater access of referral. Encouragingly, we have been able to maintain a similar standard of provision of care despite lower staffing levels and to implement the changes suggested by the original audit (thereby closing the audit loop).
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Lo KW, Kwong J, Hui AB, Chan SY, To KF, Chan AS, Chow LS, Teo PM, Johnson PJ, Huang DP. High frequency of promoter hypermethylation of RASSF1A in nasopharyngeal carcinoma. Cancer Res 2001; 61:3877-81. [PMID: 11358799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
We have investigated the genetic and epigenetic changes of a newly isolated tumor suppressor gene on 3p21.3, RASSF1A, in nasopharyngeal carcinoma (NPC). Four xenografts, four cell lines and 21 primary tumors were examined. Promoter hypermethylation of the 5'CpG island of RASSF1A was detected in 4 of 4 (100%) xenografts, in 3 of 4 (75%) cell lines, and in 14 of 21 (66.7%) primary tumors but not in the normal nasopharyngeal epithelia. Mutations were found in 2 of 21 (9.5%) primary tumors. In the cell lines and xenografts with extensive methylation, no RASSF1A gene expression was found. After treatment with 5'-aza-2'deoxycytidine, reexpression and demethylation of the RASSF1A gene were detected in a NPC cell line. These findings suggest that promoter hypermethylation may participate in the transcriptional inactivation of the RASSF1A gene in NPC. The high incidence of RASSF1A alterations suggest that it is the critical target gene on chromosome 3p21.3 involved in the development of NPC.
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Wong SS, Tan KC, Goh CL, Chan SY, Bernard HU. No association between human herpesvirus 8 and arsenical skin cancers. Int J Dermatol 2001; 40:303-4. [PMID: 11454097 DOI: 10.1046/j.1365-4362.2001.00895-4.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kearns PJ, Wang CC, Morris WJ, Low DG, Deacon AS, Chan SY, Jensen WA. Hospital care by hospital-based and clinic-based faculty: a prospective, controlled trial. ARCHIVES OF INTERNAL MEDICINE 2001; 161:235-41. [PMID: 11176737 DOI: 10.1001/archinte.161.2.235] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND The hospital length of stay decreases and clinical outcomes are maintained when teaching hospitals involve hospital-based attending physicians in comparison with traditional attending physicians. The attending physician's time commitment, including the number of hours per day and months per year, required to achieve this result is unknown. This study compared the clinical outcomes and cost of care for patients treated by hospital-based and clinic-based attending physicians devoting dramatically different amounts of time to supervising residents on the medical wards of a suburban county hospital. METHODS Patients were alternately admitted to 2 groups of ward teams. Faculty who attended 10 months of the year supervised one group. The comparison group's attending physicians were on service for 2 months or less and maintained clinic responsibilities while on service. The cost of patient care was compared by means of the length of stay, total hospital costs, and costs for ancillary services. Hospital mortality and readmission rates compared clinical outcomes. RESULTS There were 4456 patients hospitalized on the medical wards of a teaching service. No differences were detected in the length of stay (4.37 +/- 0.1 days for hospital-based and 4.39 +/- 0.1 days for clinic-based attending physicians). Hospital cost was observed to be similar (average cost, $5989 and $5977 per patient, respectively). The clinical outcomes were equivalent, with adjusted mortality rates for hospital-based attending physicians of 3.2% vs 3.9% for clinic-based attending physicians (P =.28). CONCLUSION An increase of faculty time and involvement for supervision of resident-managed hospital care did not improve clinical outcomes or decrease costs during the 1-year study period.
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Vaddi HK, Wang LZ, Ho PC, Chan SY. Effect of some enhancers on the permeation of haloperidol through rat skin in vitro. Int J Pharm 2001; 212:247-55. [PMID: 11165082 DOI: 10.1016/s0378-5173(00)00616-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The objective of this work is to enhance the permeation of haloperidol through the rat skin in vitro by using various enhancers at a concentration of 1 mg/ml in the saturated drug solution and analysing the dose-dependent diffusion profile for the enhancers which significantly increased permeation at this concentration compared with the control. Enhancers belonging to various chemical classes like the vitamins (ascorbic acid), surfactants (cetrimide, polysorbate 20), sulfoxides (dimethyl sulfoxide), glycols (polyethylene glycol 400, propylene glycol) and amides (urea) were used. Amber glass Franz-type diffusion cells were used for the permeation studies and haloperidol was made soluble in aqueous solution with the aid of lactic acid. Ascorbic acid and cetrimide increased flux and permeability coefficient significantly. From the dose-dependent permeation studies, it was concluded that ascorbic acid enhanced the permeation by increasing the solubility of the drug in the vehicle thus providing a high concentration gradient across the skin, whereas cetrimide enhanced the permeation by increasing the thermodynamic activity which may be due to solubilization of skin lipids by micelles. Polysorbate 20 decreased the enhancer index by decreasing the thermodynamic activity. None of the enhancers changed the lag time except for urea which decreased the lag time probably by its binding with keratin. Dimethyl sulfoxide, polyethylene glycol 400 and propylene glycol did not have a significant effect on haloperidol permeation compared with control.
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Chan SY, Wong RW. Expression of epidermal growth factor in transgenic mice causes growth retardation. J Biol Chem 2000; 275:38693-8. [PMID: 11001946 DOI: 10.1074/jbc.m004189200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The epidermal growth factor (EGF) family of peptides signals through the erbB family of receptor tyrosine kinases and plays important roles in development and tumorigenesis. Both EGF and transforming growth factor (TGF)-alpha only bind to erbB1 and activate it. The precursor of EGF is distinct from that of TGF-alpha in having eight additional EGF-like repeats. We have recently shown that the EGF precursor without these repeats is biologically active and leads to hypospermatogenesis in transgenic mice. Here we present evidence that the growth of transgenic mice widely expressing this engineered EGF precursor is also stunted. These mice were consistently born at half the normal weight and reached almost 80% of normal weight at adulthood. The mechanism involved a reduction of serum insulin-like growth factor-binding protein-3. Chondrocyte development in the growth plate was affected, and osteoblasts accumulated in the endosteum and periosteum. Besides these novel findings on the in vivo effects of EGF on bone development, we observed no sign of tumor formation in our transgenic animals. In contrast to previous reports on TGF-alpha transgenic mice, we show that the biological functions of EGF and TGF-alpha are clearly distinct.
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Sam WJ, Aw M, Quak SH, Lim SM, Charles BG, Chan SY, Ho PC. Population pharmacokinetics of tacrolimus in Asian paediatric liver transplant patients. Br J Clin Pharmacol 2000; 50:531-41. [PMID: 11136292 PMCID: PMC2015016 DOI: 10.1046/j.1365-2125.2000.00288.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS The purpose of this study was to describe the population pharmacokinetics of intravenous and oral tacrolimus (FK506) in 20 Asian paediatric patients, aged 1-14 years, following liver transplantation and to identify possible relationships between clinical covariates and population parameter estimates. METHODS Details of drug dosage histories, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data accumulated for at least 4 days after surgery. Before analysis, patients were randomly allocated to either the population data set (n = 16) or a validation data set (n = 4). The population data set was comprised of 771 concentration measurements of patients admitted over the last 3 years. Population modelling using the nonlinear mixed-effects model (NONMEM) program was performed on the population data set, using a one-compartment model with first-order absorption and elimination. Population average parameter estimates of clearance (CL), volume of distribution (V) and oral bioavailability (F) were sought; a number of clinical and demographic variables were tested for their influence on these parameters. RESULTS The final optimal population models related clearance to age, volume of distribution to body surface area and bioavailability to body weight and total bilirubin concentration. Predictive performance of this model evaluated using the validation data set, which comprised 86 concentrations, showed insignificant bias between observed and model-predicted blood tacrolimus concentrations. A final analysis performed in all 20 patients identified the following relationships: CL (l h-1) = 1.46 *[1 + 0. 339 * (AGE (years) -2.25)]; V (l) = 39.1 *[1 + 4.57 * (BSA (m2)-0. 49)]; F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] and F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] * [1.61], if the total bilirubin > or = 200 micromol l-1. The interpatient variabilities (CV%) in CL, V and F were 33.5%, 33.0% and 24.1%, respectively. The intrapatient variability (s.d.) among observed and model-predicted blood concentrations was 5.79 ng ml-1. CONCLUSIONS In this study, the estimates of the pharmacokinetic parameters of tacrolimus agreed with those obtained from conventional pharmacokinetic studies. It also identified significant relationships in Asian paediatric liver transplant patients between the pharmacokinetics of tacrolimus and developmental characteristics of the patients.
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Chan SY, Goodman RE, Szmuszkovicz JR, Roessler B, Eichwald EJ, Bishop DK. DNA-liposome versus adenoviral mediated gene transfer of transforming growth factor beta1 in vascularized cardiac allografts: differential sensitivity of CD4+ and CD8+ T cells to transforming growth factor beta1. Transplantation 2000; 70:1292-301. [PMID: 11087143 DOI: 10.1097/00007890-200011150-00006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have developed a model of transforming growth factor (TGF)beta1 gene transfer into mouse vascularized cardiac allografts to study the use of gene transfer as an immunosuppressive therapy in transplantation. Donor hearts were perfused with either DNA-liposome complexes or adenoviral vectors that encode the active form of human TGFbeta1. DNA-liposome mediated transfection prolonged allograft survival in approximately two-thirds of transplant recipients, while adenoviral delivery of TGFbeta1 was not protective. Protective TGFbeta1 gene transfer was associated with reduced Th1 responses and an inhibition of the alloantibody isotype switch. The protective effects of TGFbeta1 gene transfer were overridden by exogenous interleukin-12 administration. Interestingly, alloreactive CD4+ and CD8+ cells exhibited distinct sensitivities to TGFbeta1 gene transfer: CD4+ Th1 function was abrogated by this modality, although CD8+ Th1 function was not. Transient depletion of recipient CD8+ cells markedly prolonged the survival of grafts transfected with either DNA-liposome complexes or adenoviral vectors. Transgene expression persisted for at least 60 days, and Th1 responses were not detectable until CD8+ T cells repopulated the periphery. However, long-term transfected allografts appeared to exhibit exacerbated fibrosis and neointimal development. These manifestations of chronic rejection were absent in long-term transfected isografts, suggesting that long-term expression of active TGFbeta1 alone is not sufficient to induce fibrosis of the grafts. Collectively, these data illustrate the utility of immunosuppressive gene therapy as a treatment for transplantation when combined with additional conditioning regimens. Further, they illustrate that alloreactive CD4+ and CD8+ cells may be differentially influenced by cytokine manipulation strategies.
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O'Brien DW, Fu Y, Parker HR, Chan SY, Idikio H, Scott PG, Jugdutt BI. Differential morphometric and ultrastructural remodelling in the left atrium and left ventricle in rapid ventricular pacing-induced heart failure. Can J Cardiol 2000; 16:1411-9. [PMID: 11109038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
BACKGROUND Heart failure induced by rapid ventricular pacing (RVP) is associated with left atrial (LA) but not left ventricular (LV) hypertrophy. OBJECTIVE To determine whether differences in wall tension correlate with the differential ultrastructural remodelling in the LA and LV chambers, changes in ultrastructure, systolic function and wall tension (an index of wall stress) were compared in dogs after RVP (n=7) and with no RVP (n=9). RESULTS Compared with dogs with no RVP (controls), dogs with RVP had increased collagen volume fraction (5.3% versus 8.3%), myocyte cross-sectional area (245 versus 366 microm(2)) and hydroxyproline (222 versus 323 microg/mg protein) in the LA (all P<0.05), but not in the LV. The increase in systolic wall tension produced by RVP was greater in the LA (five versus 43 units, P<0.0004) than in the LV (227 versus 290 units, P<0.01) chambers and correlated closely with the collagen volume fraction (r=0.87), which in turn correlated with myocyte cross-sectional area (r=0.98). In the left atrium, wall tension correlated with wall stress (r=0.99). CONCLUSIONS The results suggest that differential wall tension may provide the stimulus for differential ultrastructural remodelling (with more hypertrophy and collagen) between LA and LV chambers in RVP-induced cardiomyopathy.
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Chan SY, Osborne AW, Purkiss SF. Cholelithoptysis: an unusual complication following laparoscopic cholecystectomy. Dig Surg 2000; 15:707-8. [PMID: 9845642 DOI: 10.1159/000018663] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
A 75-year old lady underwent a routine laparoscopic cholecystectomy during which stones were spilled into the peritoneal cavity. Despite peritoneal lavage the patient developed chronic right upper quadrant discomfort and a pleural effusion over several months. Following the production of a pigmented bilirubin stone in her sputum the patient's symptoms resolved. Cholelithoptysis is a rare complication of laparoscopic cholecystectomy, the diagnosis should be considered in patients with prolonged chest symptoms after surgery.
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Lin HS, Chean CS, Ng YY, Chan SY, Ho PC. 2-hydroxypropyl-beta-cyclodextrin increases aqueous solubility and photostability of all-trans-retinoic acid. J Clin Pharm Ther 2000; 25:265-9. [PMID: 10971776 DOI: 10.1046/j.1365-2710.2000.00285.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND All-trans-retinoic acid (ATRA, vitamin A acid or tretinoin) is effective in the treatment of acute promyelocytic leukaemia (APL). Unfortunately, the oral absorption of ATRA is highly variable. Its poor aqueous solubility also makes it difficult to be formulated into parenteral formulation. To date, there is no parenteral formulation of ATRA available commercially. OBJECTIVE To undertake the preformulation work necessary for developing such a product. METHOD We investigated the solubility and stability profile of ATRA in various formulations. RESULTS The aqueous solubility of ATRA could be greatly increased by the inclusion of ATRA in 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). Adjusting the pH value further improved the water solubility of ATRA. The photostability of HP-beta-CD-based formulation of ATRA was evaluated and it was found that inclusion ATRA into HP-beta-CD did improve the photostability of ATRA. CONCLUSION These results showed that it is possible to develop a parenteral formulation and/or an aqueous oral formulation of all-trans-retinoic acid by using 2-hydroxypropyl-beta-cyclodextrin. However, the biopharmaceutical properties of such a formulation would be necessary before its use.
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Ip WK, Lau YL, Chan SY, Mok CC, Chan D, Tong KK, Lau CS. Mannose-binding lectin and rheumatoid arthritis in southern Chinese. ARTHRITIS AND RHEUMATISM 2000; 43:1679-87. [PMID: 10943857 DOI: 10.1002/1529-0131(200008)43:8<1679::aid-anr3>3.0.co;2-d] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Insufficiency of mannose-binding lectin (MBL) is associated with recurrent infections. Rheumatoid arthritis (RA) may represent an aberrant immune response to infections. This study examined the phenotypic expression and variant alleles of the MBL gene and its etiologic role in Chinese with RA. METHODS We studied 211 RA patients and 196 healthy subjects. Serum MBL concentrations and codon-54 mutation of the MBL gene and its promoter polymorphisms were analyzed. Clinical characteristics and disease activity were also examined. RESULTS Patients with RA had significantly lower serum MBL levels and higher frequency of codon-54 mutation of the MBL gene compared with controls. Additionally, there was a significant difference in the distribution of promoter polymorphisms, H/L, between RA patients and controls, although the frequencies of Y/X and those of nonstructural polymorphisms, P/Q, did not differ between the 2 groups. Furthermore, patients with RA had a lower incidence of the highest-producing haplotype HY and a higher incidence of the lowest-producing haplotype LX compared with controls. Serum MBL levels did not correlate with drug treatment or with disease activity. However, patients with erosive and serious extraarticular disease had significantly lower serum MBL levels than those without these disease manifestations at the time of study. Also, significantly more patients with erosive disease had a codon-54 mutation of the MBL gene compared with those with nonerosive disease. CONCLUSION The codon-54 mutation and low-producing promoter polymorphisms of the MBL gene are associated with RA. A low serum level of MBL predisposes to the development of RA and is a risk factor for severe disease in southern Chinese.
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Wong MP, Chan SY, Fu KH, Leung SY, Cheung N, Yuen ST, Chung LP. The angiopoietins, tie2 and vascular endothelial growth factor are differentially expressed in the transformation of normal lung to non-small cell lung carcinomas. Lung Cancer 2000; 29:11-22. [PMID: 10880843 DOI: 10.1016/s0169-5002(00)00118-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The successful establishment of angiogenesis depends on a complex process of endothelial proliferation and organization. The angiopoietins (Ang-1 and Ang-2) and Tie2 ligand-receptor system is essential for the regulation of vascular maturation and stability during embryonic development. Together with the vascular endothelial growth factor (VEGF)-mediated pathway, they have been implicated in the control of normal physiological angiogenesis. We investigated their potential role and interaction in the development of lung cancers by comparing the expression pattern and inter-relationship of Ang-1 and 2, Tie2 and VEGF levels in 28 pairs of primary non-small cell lung cancers (NSCLC) and normal lung. Using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and in-situ hybridization (ISH), we showed that in NSCLC, there was significantly up-regulated VEGF expression by the tumour cells and an increased intensity of Ang-2 expression in the tumour vessels. The number of Ang-2-expressing vessels also correlated with the grades of tumour cell expression of VEGF. On the other hand, normal lung expressed constitutively high and correlated levels of Ang-1 and Tie2, which were significantly reduced in the carcinomas. The findings suggested a role of the Ang-1/Tie2 pathway in the maintenance of the complex vasculature in normal lung, while collaborative activities between the Ang-2 and VEGF pathways might be important in promoting tumour angiogenesis in NSCLC.
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Lo KW, Teo PM, Hui AB, To KF, Tsang YS, Chan SY, Mak KF, Lee JC, Huang DP. High resolution allelotype of microdissected primary nasopharyngeal carcinoma. Cancer Res 2000; 60:3348-53. [PMID: 10910036] [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
Nasopharyngeal carcinoma (NPC) is a common cancer in South China but is rare in other parts of the world. To better understand the molecular basis of this cancer, we performed high-resolution allelotyping on 27 microdissected primary tumors using 382 microsatellite markers. We have detected high frequencies of allelic imbalance on 3p (96.3%), 9p (85.2%), 9q (88.9%), 11q (74.1%), 12q (70.4%), 13q (55.6%), 14q (85.2%), and 16q (55.6%). Nonrandom allelic changes of 12q and 16q were revealed for the first time. In addition, loss of heterozygosity on chromosomal arms 1p (37.0%), 5q (44.4%), and 12p (44.4%) were also common in NPC. Multiple minimally deleted regions, 7-40 cM, were identified at 3p14-24.2, 11q21-23, 13q12-14, 13q31-32, 14q24-32, and 16q22-23. Frequent deletions of these minimally deleted regions implied the presence of tumor suppressor genes that may be involved in the development of NPC. Consistent loss of heterozygosity on 3p, 9p, and 14q in almost all tumors suggested that such changes are critical events in NPC tumorigenesis.
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MESH Headings
- Alleles
- Biopsy
- Chromosome Mapping
- Chromosomes, Human, Pair 11
- Chromosomes, Human, Pair 12
- Chromosomes, Human, Pair 13
- Chromosomes, Human, Pair 14
- Chromosomes, Human, Pair 16
- Chromosomes, Human, Pair 3
- Chromosomes, Human, Pair 9
- Dissection
- Genetic Markers
- Humans
- Loss of Heterozygosity
- Microsatellite Repeats
- Nasopharyngeal Neoplasms/genetics
- Nasopharyngeal Neoplasms/pathology
- Nasopharyngeal Neoplasms/surgery
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Wong RW, Kwan RW, Mak PH, Mak KK, Sham MH, Chan SY. Overexpression of epidermal growth factor induced hypospermatogenesis in transgenic mice. J Biol Chem 2000; 275:18297-301. [PMID: 10748057 DOI: 10.1074/jbc.m001965200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The in vivo role of epidermal growth factor (EGF) is not well defined even though its effects on culture cells were well studied. To understand the developmental, physiological, and pathological roles of EGF, we have generated transgenic mice widely expressing human EGF with the use of the beta-actin promoter. EGF and transforming growth factor alpha (TGFalpha) bind with equal affinity to the EGF receptor, a transmembrane tyrosine kinase, to trigger various biological responses. EGF and TGFalpha signaling are implicated in the development of the reproductive system. EGF also plays a physiological role in reproduction. Removal of the salivary gland in rodents, which reduces circulating EGF, reduces spermatogenesis, which can be corrected by EGF replacement. Here we show that in our transgenic males, only few post-meiosis II gametes were found, and the mice were sterile. This resembles a common cause of infertility in humans. Furthermore, the transgenic males had reduced serum testosterone. Our findings contrast the previous report on transgenic mice overexpressing TGFalpha in testis, which showed normal spermatogenesis. These data suggest that EGF is the active ligand for EGF receptor reported in germ cells, and proper EGF expression is important for completion of spermatogenesis.
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121
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Gillespie AM, Broadhead TJ, Chan SY, Owen J, Farnsworth AP, Sopwith M, Coleman RE. Phase I open study of the effects of ascending doses of the cytotoxic immunoconjugate CMB-401 (hCTMO1-calicheamicin) in patients with epithelial ovarian cancer. Ann Oncol 2000; 11:735-41. [PMID: 10942064 DOI: 10.1023/a:1008349300781] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE We have performed a phase I study of the cytotoxic immunoconjugate CMB-401 in women with epithelial ovarian cancer (EOC). CMB-401 is a directed chemotherapy that comprises a genetically engineered human antibody against polymorphic epithelial mucin, to which is attached covalently two to three molecules, on average, of the cytotoxic antibiotic calicheamicin. The primary objectives of this two-centre study were to identify end-organ toxicities and to establish the maximum tolerated dose (MTD). PATIENTS AND METHODS Thirty-four patients aged 37-75 years with progressive EOC not amenable to platinum/standard therapy, and with satisfactory WHO performance status (0-2) were recruited. Patients had received a mean of 3.2 previous chemotherapeutic regimens with a median interval since last chemotherapy of 182 days (range 34-1217). Patients received up to four cycles of a dual infusion of 35 mg/m2 hCTMO1 'predose' followed by doses of CMB-401 which were increased for each cohort--a regimen which minimises drug uptake in normal tissues whilst enhancing delivery to the ovarian tumour. CMB-401 dosing commenced at 2 mg/m2 and progressed via seven cohorts to 16 mg/m2. RESULTS CMB-401 was generally well tolerated. However, transient fever and emesis occurred, necessitating routine prophylaxis, and increasingly significant malaise was reported as the dose increased. WHO grade 3-4 toxicities, irrespective of causality, included: anaemia 21%, granulocytopenia 9%, thrombocytopenia 9%, liver transaminases 3%, sepsis 3%, haemorrhage 6%, nausea/vomiting 76%; pulmonary 6%, and conscious state/somnolence 6%. The MTD was reached at 16 mg/m2. During the study four patients had a greater than 50% reduction in CA125, and three patients had radiological evidence of reduction in tumour bulk. CONCLUSIONS CMB-401 appears to have an acceptable toxicity profile with demonstrable activity against EOC.
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Wong RW, Sham MH, Lau YL, Chan SY. An efficient method of generating transgenic mice by pronuclear microinjection. Mol Biotechnol 2000; 15:155-9. [PMID: 10949829 DOI: 10.1385/mb:15:2:155] [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: 11/11/2022]
Abstract
Genetic transformation of mice using pronuclear microinjection was demonstrated by a number of groups in rapid succession in the early 1980's. Since that time, studies using transgenic animals have produced major advances in biomedical sciences and molecular genetics. More important, it is possible to study the molecular basis for tissue and stage-specific expression of genes. We recently used this method to generate transgenic mice. DNA fragment (transgene) was injected into the pronucleus of one-cell embryos. We describe this simplified protocol, which is reliable. With the use of buffered medium M2 for the whole process, it is not mandatory to have a CO2 incubator.
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123
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Chan SY, Speck RF, Ma MC, Goldsmith MA. Distinct mechanisms of entry by envelope glycoproteins of Marburg and Ebola (Zaire) viruses. J Virol 2000; 74:4933-7. [PMID: 10775638 PMCID: PMC112022 DOI: 10.1128/jvi.74.10.4933-4937.2000] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since the Marburg (MBG) and Ebola (EBO) viruses have sequence homology and cause similar diseases, we hypothesized that they associate with target cells by similar mechanisms. Pseudotype viruses prepared with a luciferase-containing human immunodeficiency virus type 1 backbone and packaged by the MBG virus or the Zaire subtype EBO virus glycoproteins (GP) mediated infection of a comparable wide range of mammalian cell types, and both were inhibited by ammonium chloride. In contrast, they exhibited differential sensitivities to treatment of target cells with tunicamycin, endoglycosidase H, or protease (pronase). Therefore, while they exhibit certain functional similarities, the MBG and EBO virus GP interact with target cells by distinct processes.
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124
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Wong RW, Chan SY. Semiquantitative immunoblots of membrane protein-epidermal growth factor. Mol Biotechnol 2000; 15:65-7. [PMID: 10911623 DOI: 10.1385/mb:15:1:65] [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: 11/11/2022]
Abstract
Membrane proteins or cytokines are sometimes difficult to isolate and purify. Our group recently concentrated on epidermal growth factor (EGF) protein expression studies. Mature EGF was initially identified from mouse submaxillary gland extract as a stimulator of eyelid opening and incisor eruption when injected into newborn mice and rats. The EGF precursor is a transmembrane protein with eight additional EGF-like repeats. Our previous study has shown that the EGF precursor without these eight EGF-like repeats (hEGF) was biologically active. Here, we introduce a modified method for rapid detection of hEGF. The membranous protein was directly extracted from various organs of transgenic mice (including the submandibular gland, kidney, liver, heart, and testis) with two different buffers and easily detected by semiquantitative immunoblotting.
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Abstract
Bruton's tyrosine kinase (BTK) is involved in B-cell development. Mutation of BTK results in X-linked agammaglobulinemia (XLA). BTK is expressed in most haemopoietic lineages except mature T cells and plasma cells. We identified six novel and two known mutations of BTK in 11 Chinese XLA patients from 8 families. Family 1 had a novel point mutation at the start codon (135G-->T) in exon 2. Family 2 had known mutation of single A insertion in a stretch of 7 A residues (341-347insA) recognized as mutation hotspot in exon 3. Family 3 had a novel point mutation in exon 11 (1074A-->G) which led to aberrant splicing. Family 4 had known mutation in exon 19 (2053C-->T) in CpG mutation hotspot. The novel mutation of family 5 was an A deleted in a run of three As (1017-1019delA) in exon 10. In family 6, exons 2 and 3 were lost in BTK mRNA, a novel deletion. Family 7 had a novel substitution in exon 2 (227T-->C) which led to change of a conserved leucine to serine. Family 8 had a novel point mutation at beginning of intron 14 (IVS14+ 6 T-->G) resulting in aberrant splicing. Hum Mutat 15:385, 2000.
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