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1.
Hong Kong Med J ; 28(6): 475-481, 2022 12.
Article in English | MEDLINE | ID: mdl-35815480

ABSTRACT

INTRODUCTION: Kidney cancer, primarily renal cell carcinoma (RCC), ranks among the top 10 most common malignancies in the male population of Hong Kong. In 2019, members of two medical societies in Hong Kong formed an expert panel to establish a set of consensus statements for the management of metastatic RCC. On 22 June 2021, the same panel met to review recent evidence and reassess their positions regarding the management of advanced and metastatic RCC, with the aim of providing recommendations for physicians in Hong Kong. PARTICIPANTS: The panel included 12 experts (6 clinical oncologists and 6 urologists) who had extensive experience managing patients with RCC in Hong Kong. EVIDENCE: The panel reviewed randomised controlled trials, observational studies, systematic reviews/meta-analyses, and international clinical guidelines to address key clinical questions that were identified before the meeting. CONSENSUS PROCESS: In total, 15 key clinical questions were identified before the meeting, covering the surgical and systemic treatment of advanced or metastatic clear cell, sarcomatoid, and non-clear cell RCCs. At the meeting, the panellists voted on these questions, then discussed relevant evidence and practical considerations. CONCLUSIONS: The treatment landscape for advanced and metastatic RCC continues to evolve. More immune checkpoint inhibitor (ICI)-based combination regimens will be indicated for the treatment of metastatic clear cell RCC. There is increasing evidence concerning the benefit of adjuvant ICI treatment for resected advanced RCC. This article summarises recent evidence and expert insights regarding a series of key clinical questions about the management of advanced and metastatic RCC.


Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Humans , Male , Carcinoma, Renal Cell/therapy , Kidney Neoplasms/therapy , Hong Kong/epidemiology , Consensus , Societies, Medical
2.
Ann Oncol ; 31(6): 769-779, 2020 06.
Article in English | MEDLINE | ID: mdl-32217076

ABSTRACT

BACKGROUND: After curative radiotherapy (RT) or chemoradiation (CRT), there is no validated tool to accurately identify patients for adjuvant therapy in nasopharyngeal carcinoma (NPC). Post-RT circulating plasma Epstein-Barr virus (EBV) DNA can detect minimal residual disease and is associated with recurrence and survival independent of TNM (tumor-lymph node-metastasis) stage. We aimed to develop and validate a risk model for stratification of NPC patients after completion of RT/CRT to observation or adjuvant therapy. PATIENTS AND METHODS: The prospective multicenter 0502 EBV DNA screening cohort (Hong Kong NPC Study Group 0502 trial) enrolled from 2006 to 2015 (n = 745) was used for model development. For internal validation, we pooled independent patient cohorts from prospective clinical studies enrolled from 1997 to 2006 (n = 340). For external validation, we used retrospective cohort of NPC patients treated at Sun Yat-sen University Cancer Center from 2009 to 2012 (n = 837). Eligible patients had histologically confirmed NPC of Union for International Cancer Control (UICC) 7th Edition stage II-IVB who completed curative RT/CRT with or without neoadjuvant chemotherapy, had post-RT EBV DNA tested within 120 days after RT and received no adjuvant therapy. The primary end point was overall survival (OS). We used recursive-partitioning analysis (RPA) to classify patients into groups of low, intermediate, and high risk of death. RESULTS: Combining post-RT EBV DNA level (0, 1-49, 50-499, and ≥500 copies/ml) and TNM stage (II, III, IVAB), RPA model classified patients into low-, intermediate-, and high-risk groups with 5-year OS of 89.4%, 78.5% and 37.2%, respectively. The RPA low-risk group had comparable OS to TNM stage II (5-year OS 88.5%) but identified more patients (64.8% versus stage II 28.1%) that could potentially be spared adjuvant therapy toxicity. The RPA model (c-index 0.712) showed better risk discrimination than either the TNM stage (0.604) or post-RT EBV DNA alone (0.675) with improved calibration and consistence. These results were validated in both internal and external cohorts. CONCLUSION: Combining post-RT EBV DNA and TNM stage improved risk stratification in NPC.


Subject(s)
Epstein-Barr Virus Infections , Nasopharyngeal Neoplasms , DNA, Viral/genetics , Epstein-Barr Virus Infections/pathology , Herpesvirus 4, Human/genetics , Humans , Nasopharyngeal Carcinoma/therapy , Nasopharyngeal Neoplasms/radiotherapy , Neoplasm Recurrence, Local , Neoplasm Staging , Plasma , Prognosis , Prospective Studies , Retrospective Studies , Risk Assessment
3.
J Environ Manage ; 244: 462-471, 2019 Aug 15.
Article in English | MEDLINE | ID: mdl-31154109

ABSTRACT

Urban centres acquire and accumulate many materials from their hinterland, among these are nutrient elements such as nitrogen (N). The popular North American vision of a peri-urban setting is one where urban food production, composting and re-cycling are assumed to limit urban accumulation of nutrients. This study quantifies this assumption using the Lower Fraser Valley (LFV) of British Columbia as an example, ideal because it is surrounded by mountains, ocean and an international border which collectively delimit the peri-urban boundaries. Nitrogen influxes are dominated by livestock feed imports to support dairy and poultry production (18000 tonnes N), followed by human food imports (9210 tonnes N), as well as 5410 tonnes N as fertilizer and 4690 tonnes N in atmospheric deposition. There is a transfer of 6700 tonnes N from agricultural to urban ecosystems displacing food imports, but food production contributes to the N footprint of the LFV. Nitrogen effluxes are dominated by sewage disposal (10400 tonnes N), solid waste disposal (7020 tonnes N) and atmospheric emissions (9460 tonnes N). The total influx is 15 kg N per person, the net influx is 3.1 kg N per person. Per unit land area, these are a total influx of 24 kg N/ha and a net influx of 4.7 kg N/ha. The atmospheric emissions are 4.7 kg N per person and 7.2 kg/ha. The N in soil is mobile and it is assumed soil N is at a steady state concentration, thus the surplus N is lost from the soil, probably by leaching and runoff. The Fraser River is estimated to acquire and transport 5230 tonnes N from the region into the ocean each year, in addition to 10300 tonnes N from sewage outfall. This is coupled with effluxes of phosphorus (estimated previously), and the result probably has an impact on the coastal waters. There is little reuse of imported N and current waste management practices including composting and combustion do little to improve N efficiency.


Subject(s)
Ecosystem , Nitrogen Cycle , Animals , British Columbia , Fertilizers , Humans , Nitrogen
4.
Clin Radiol ; 73(7): 640-646, 2018 07.
Article in English | MEDLINE | ID: mdl-29636188

ABSTRACT

AIM: To investigate four methods to measure the maximum dimension (MD) of metastatic neck nodes and correlate with clinical outcome in nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Magnetic resonance imaging (MRI) examinations of 712 NPC patients were analysed. MD measurements using methods 1, 2, 3, and 4 were obtained from a single node in the axial plane; a single node in the axial/coronal plane; a single and/or confluent nodes in the axial/coronal plane; and a single and/or confluent and/or contiguous nodes in the axial/coronal plane, respectively. MDs obtained from the four methods were correlated with nodal volume (NV) using Pearson's correlation test. MDs obtained from the four methods, T and N stages, age, gender, and treatment were correlated with overall survival (OS), disease-specific survival (DSS), distant metastases free survival (DMFS), and regional relapse-free survival (RRFS) using cox regression. RESULTS: Method 4 (R: 0.84) had the strongest correlation with NV followed by method 3 (R: 0.77), method 2 (R: 0.70) and method 1(R: 0.69). Method 4 was the only independent nodal measurement of OS, DSS, and DMFS (p-values = 0.008, <0.001 and <0.001, respectively). None of the MD methods was an independent measurement of RRFS. CONCLUSIONS: The best method to obtain the MD for staging incorporates not only single and confluent, but also contiguous metastatic nodes measured in the plane with the MD.


Subject(s)
Lymphatic Metastasis/diagnostic imaging , Lymphatic Metastasis/pathology , Magnetic Resonance Imaging/methods , Nasopharyngeal Carcinoma/pathology , Nasopharyngeal Neoplasms/pathology , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Lymph Nodes/diagnostic imaging , Lymph Nodes/pathology , Male , Middle Aged , Neck , Neoplasm Staging , Reproducibility of Results , Retrospective Studies , Young Adult
5.
Hong Kong Med J ; 23(2): 134-9, 2017 Apr.
Article in English | MEDLINE | ID: mdl-27909268

ABSTRACT

INTRODUCTION: Surgical resection used to be the mainstay of treatment for glioma. In the last decade, however, opinion has changed about the goal of surgical resection in treating glioma. Ample evidence shows that maximum safe resection in glioblastoma improves survival. Neurosurgeons have therefore revised their objective of surgery from diagnostic biopsy or limited debulking to maximum safe resection. Given these changes in the management of glioma, we compared the survival of local Chinese patients with glioblastoma multiforme over a period of 10 years. METHODS: We retrospectively reviewed the data of the brain tumour registry of the CUHK Otto Wong Brain Tumour Centre in Hong Kong. Data of patients with glioblastoma multiforme were reviewed for two periods, during 1 January 2003 to 31 December 2005 and 1 January 2010 to 31 December 2012. Overall survival during these two periods of time was assessed by Kaplan-Meier survival estimates. Risk factors including age, type and extent of resection, use of chemotherapy, and methylation status of O6-methylguanine-DNA methyltransferase were also assessed. RESULTS: There were 26 patients with glioblastoma multiforme with a mean age of 52.2 years during 2003 to 2005, and 42 patients with a mean age of 55.1 years during 2010 to 2012. The mean overall survival during these two periods was 7.4 months and 12.7 months, respectively (P<0.001). The proportion of patients who underwent surgical resection was similar: 69.2% in 2003 to 2005 versus 78.6% in 2010 to 2012 (P=0.404). There was a higher proportion of patients in whom surgery achieved total removal in 2010 to 2012 than in 2003 to 2005 (35.7% and 7.7%, respectively; P=0.015). During 2010 to 2012, patients who were given concomitant chemoradiotherapy showed definitively longer survival than those who were not (17.9 months vs 4.5 months; P=0.001). The proportion of patients who survived 2 years after surgery increased from 11.5% in 2003 to 2005 to 21.4% in 2010 to 2012. CONCLUSIONS: Hong Kong has made substantial improvements in the management of glioblastoma multiforme over the last decade with corresponding improved survival outcomes. The combination of an aggressive surgical strategy and concomitant chemoradiotherapy are probably the driving force for the improvement.


Subject(s)
Brain Neoplasms/mortality , Brain Neoplasms/therapy , Glioblastoma/mortality , Glioblastoma/therapy , Brain Neoplasms/genetics , Combined Modality Therapy/methods , DNA Methylation , Disease-Free Survival , Female , Glioblastoma/genetics , Hong Kong , Humans , Kaplan-Meier Estimate , Male , Middle Aged , O(6)-Methylguanine-DNA Methyltransferase/genetics , Registries , Retrospective Studies
6.
Hong Kong Med J ; 23(6): 599-608, 2017 Dec.
Article in English | MEDLINE | ID: mdl-29125123

ABSTRACT

INTRODUCTION: Stereotactic brain radiosurgery provides good local control in patients with limited brain metastases. A newly developed frameless system allows pain-free treatment. We reviewed the effectiveness of this frameless stereotactic brain radiosurgery and identified prognostic factors that may aid better patient selection. METHODS: Medical records of patients with brain metastases treated with linear accelerator-based frameless stereotactic brain radiosurgery between January 2010 and July 2015 in a university affiliated hospital in Hong Kong were reviewed. Outcomes including local and distant brain control rate, progression-free survival, and overall survival were analysed. Prognostic factors were identified by univariable and multivariable analyses. Association of outcomes with four common prognostic scores was performed. RESULTS: In this study, 64 patients with 94 lesions were treated with a median dose of 18 Gy (range, 12-22 Gy) in a single fraction. The median follow-up was 11.5 months. One-year actuarial local and distant brain control rates were 72% and 71%, respectively. The median overall survival was 13.0 months. On multivariable analysis, Karnofsky performance status score (>50 vs ≤50) and number of lesions (1-2 vs ≥3) were found to associate significantly with distinct brain progression-free survival (P=0.022, hazard ratio=0.20, 95% confidence interval 0.05-0.80 and P=0.003, hazard ratio=0.31, 95% confidence interval 0.14-0.68, respectively). Overall survival was associated significantly with Basic Score for Brain Metastases (P=0.031), Score Index for Radiosurgery in Brain Metastases (P=0.007), and Graded Prognostic Assessment (P=0.003). Improvement in overall survival was observed in all groups of different prognostic scores. CONCLUSION: Frameless stereotactic brain radiosurgery is effective in patients with oligo-metastases of brain and should be increasingly considered in patients with favourable prognostic scoring.


Subject(s)
Brain Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Brain Neoplasms/mortality , Brain Neoplasms/secondary , Disease-Free Survival , Female , Hong Kong , Humans , Karnofsky Performance Status , Lung Neoplasms/pathology , Male , Middle Aged , Neoplasm Metastasis , Prognosis , Radiosurgery , Radiotherapy Dosage , Treatment Outcome , Young Adult
7.
Hong Kong Med J ; 23(6): 594-8, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28798282

ABSTRACT

INTRODUCTION: Temozolomide is the first chemotherapeutic agent proven effective for patients with newly diagnosed glioblastoma. The drug is well tolerated for its low toxicity. The current standard practice is concomitant chemoradiotherapy for 6 weeks followed by 6 cycles of adjuvant temozolomide. Some Caucasian studies have suggested that patients might benefit from extended adjuvant cycles of temozolomide (>6 cycles) to lengthen both progression-free survival and overall survival. In the present study, we compared differences in survival and toxicity profile between patients who received conventional 6-cycle temozolomide and those who received more than 6 cycles of temozolomide. METHODS: Patients with newly diagnosed glioblastoma without progressive disease and completed concomitant chemoradiotherapy during a 4-year period were studied. Progression-free survival was compared using Kaplan-Meier survival curves. t Test, U test, and correlation were chosen accordingly to examine the impact of age, extent of resection, MGMT promoter methylation status and adjuvant cycles on progression-free survival. For factors with a P value of <0.05 in univariate analyses, Cox regression hazard model was adopted to determine the strongest factors related to progression-free survival. RESULTS: The median progression-free survival was 17.0 months for patients who received 6 cycles of temozolomide (n=7) and 43.4 months for those who received more than 6 cycles (n=7) [P=0.007, log-rank test]. Two patients in the former group and one in the latter group encountered grade 1 toxicity and recovered following dose adjustment. Cycles of adjuvant temozolomide were correlated with progression-free survival (P=0.016, hazard ratio=0.68). CONCLUSION: Extended cycles of temozolomide are safe and feasible for Chinese patients with disease responsive to temozolomide.


Subject(s)
Antineoplastic Agents, Alkylating/therapeutic use , Brain Neoplasms/drug therapy , Dacarbazine/analogs & derivatives , Glioblastoma/drug therapy , Adult , Aged , Antineoplastic Agents, Alkylating/administration & dosage , Brain Neoplasms/mortality , Brain Neoplasms/radiotherapy , Chemoradiotherapy , Chemotherapy, Adjuvant , Dacarbazine/administration & dosage , Dacarbazine/therapeutic use , Disease-Free Survival , Drug Administration Schedule , Feasibility Studies , Female , Glioblastoma/mortality , Glioblastoma/radiotherapy , Hong Kong , Humans , Male , Middle Aged , Registries , Retrospective Studies , Temozolomide
8.
J Environ Manage ; 187: 286-297, 2017 Feb 01.
Article in English | MEDLINE | ID: mdl-27914350

ABSTRACT

Excess phosphorus (P) in peri-urban regions is an emerging issue, whereas there is global depletion of quality mined supplies of P. The flow of P across the landscape leading to regional surpluses and deficits is not well understood. We computed a regional P budget with internal P flows in a fairly discreet peri-urban region (Lower Fraser Valley, BC) with closely juxtaposed agricultural and non-agricultural urban ecosystems, in order to clarify the relationship between food production, food consumption and other activities involving use of P (e.g. keeping pets and horses and using soaps). We hypothesized changes that might notably improve P efficiency in peri-urban settings and wider regions. Livestock feed for the dairy and poultry sectors was the largest influx of P: the peri-urban land is too limited to grow feed grains and they are imported from outside the region. Fertilizer and import of food were the next largest influxes of P and a similar amount of P flows as food from the agricultural to urban ecosystems. Export of horticultural crops (berries and greenhouse crops) and poultry represented agricultural effluxes that partially offset the influxes. P efficiency was lower for horticultural production (21%) than animal production (32%), the latter benefited from importing feed crops, suggesting a regional advantage for animal products. There was 2.0, 3.8, 5.7 and 5.6 tonnes imported P per $ million farm cash receipts for horticulture, dairy, poultry meat and eggs. Eliminating fertilizer for corn and grass would reduce the ratio for the dairy industry. The net influx, dominated by fertilizer, animal feed and food was 8470 tonnes P per year or 3.2 kg P per person per year, and of this the addition to agricultural soils was 3650 tonnes P. The efflux in sewage effluent to the sea was 1150 tonnes P and exported sewage solids was 450 tonnes P. Municipal solid waste disposal was most difficult to quantify and was about 1800 tonnes P, 80% of which was partly reused in the urban regions and partly sequestered in landfill, which may be considered an efflux or a surplus. Reuse of rendering waste for feeding poultry significantly reduced P importation, but no rendering waste is used for cattle due to health concerns. Sensitivity analysis showed that variation in human population and the amount of P consumed per person in chicken and dairy products had the most influence on the total movement of P from agricultural to urban-ecosystems. There are current farm practices that mitigate P surpluses and new technologies are being developed to further reduce farm imbalances. However, current waste management policies that promote practices such composting of home wastes and exporting of poultry manure and biosolids to semiarid rangeland do little to enhance overall P cycling because the P is not returned to the farms producing feed and food for the peri-urban region. Sequestering in landfills may be a better solution until better ways are found to return surplus P.


Subject(s)
Food Industry , Phosphorus/analysis , Agriculture , Animal Feed/analysis , Animals , Cattle , Crops, Agricultural , Ecosystem , Environment , Fertilizers , Geography , Humans , Industrial Waste , Manure , Poultry , Refuse Disposal , Sewage , Soil , Waste Disposal Facilities , Waste Management
9.
Hong Kong Med J ; 19(5): 407-15, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23784530

ABSTRACT

OBJECTIVE: To report the treatment efficacy and toxicity profile of intensitymodulated radiation therapy in Chinese patients with clinically localised prostate cancer. DESIGN: Historical cohort study. SETTING: Oncology unit in a university teaching hospital in Hong Kong. PATIENTS: Patients with clinically localised prostate cancer undergoing intensity-modulated radiation therapy in our institution between May 2001 and November 2009 were reviewed. MAIN OUTCOME MEASURES: The 5-year biochemical failure­free survival, 5-year overall survival, as well as acute/late gastro-intestinal toxicities and genito-urinary toxicities. RESULTS: A total of 182 patients were treated with prostate intensitymodulated radiation therapy with or without whole-pelvic radiotherapy. The median follow-up was 44 months. The median patient age was 72 years. Overall survival of the cohort was 92% after 5 years. The favourable, intermediate, and unfavourable risk category distributions of the National Comprehensive Cancer Network were 21 (12%), 42 (23%), and 119 (65%), respectively. The 5-year actuarial biochemical failure­free survival rates for patients in these categories were 95%, 82%, and 80%, respectively. Multivariate analysis identified early tumour stage, low pre-treatment prostate-specific antigen levels, and the use of adjuvant androgen deprivation as independent prognostic factors for better biochemical failure­free survival. Grade 2 and 3 late gastro-intestinal/genito-urinary toxicities occurred in 8%/3% and 4%/3% of the patients, respectively. CONCLUSION: Intensity-modulated radiation therapy for prostate cancer is feasible and safe in the Chinese population. These data are consistent with the results of other series in Caucasian populations.


Subject(s)
Prostate-Specific Antigen/blood , Prostatic Neoplasms/radiotherapy , Radiotherapy, Intensity-Modulated/methods , Aged , Aged, 80 and over , Disease-Free Survival , Feasibility Studies , Follow-Up Studies , Gastrointestinal Diseases/epidemiology , Gastrointestinal Diseases/etiology , Hong Kong , Hospitals, University , Humans , Male , Middle Aged , Multivariate Analysis , Prognosis , Prostatic Neoplasms/pathology , Radiotherapy, Intensity-Modulated/adverse effects , Retrospective Studies , Survival Rate , Time Factors , Treatment Outcome , Urogenital System/radiation effects
11.
AJNR Am J Neuroradiol ; 41(12): 2339-2344, 2020 12.
Article in English | MEDLINE | ID: mdl-33122214

ABSTRACT

BACKGROUND AND PURPOSE: T1ρ imaging is a new quantitative MR imaging pulse sequence with the potential to discriminate between malignant and benign tissue. In this study, we evaluated the capability of T1ρ imaging to characterize tissue by applying T1ρ imaging to malignant and benign tissue in the nasopharynx and to normal tissue in the head and neck. MATERIALS AND METHODS: Participants with undifferentiated nasopharyngeal carcinoma and benign hyperplasia of the nasopharynx prospectively underwent T1ρ imaging. T1ρ measurements obtained from the histogram analysis for nasopharyngeal carcinoma in 43 participants were compared with those for benign hyperplasia and for normal tissue (brain, muscle, and parotid glands) in 41 participants using the Mann-Whitney U test. The area under the curve of significant T1ρ measurements was calculated and compared using receiver operating characteristic analysis and the Delong test, respectively. A P < . 05 indicated statistical significance. RESULTS: There were significant differences in T1ρ measurements between nasopharyngeal carcinoma and benign hyperplasia and between nasopharyngeal carcinoma and normal tissue (all, P < . 05). Compared with benign hyperplasia, nasopharyngeal carcinoma showed a lower T1ρ mean (62.14 versus 65.45 × ms), SD (12.60 versus 17.73 × ms), and skewness (0.61 versus 0.76) (all P < .05), but no difference in kurtosis (P = . 18). The T1ρ SD showed the highest area under the curve of 0.95 compared with the T1ρ mean (area under the curve = 0.72) and T1ρ skewness (area under the curve = 0.72) for discriminating nasopharyngeal carcinoma and benign hyperplasia (all, P < .05). CONCLUSIONS: Quantitative T1ρ imaging has the potential to discriminate malignant from benign and normal tissue in the head and neck.


Subject(s)
Magnetic Resonance Imaging/methods , Nasopharyngeal Carcinoma/diagnostic imaging , Nasopharyngeal Neoplasms/diagnostic imaging , Nasopharynx/diagnostic imaging , Nasopharynx/pathology , Adult , Aged , Aged, 80 and over , Female , Head/diagnostic imaging , Humans , Hyperplasia/diagnostic imaging , Image Interpretation, Computer-Assisted/methods , Male , Middle Aged , Neck/diagnostic imaging , ROC Curve , Statistics, Nonparametric
12.
Mol Cell Biol ; 9(8): 3253-9, 1989 Aug.
Article in English | MEDLINE | ID: mdl-2552288

ABSTRACT

The insulin gene is expressed almost exclusively in pancreatic beta-cells. The DNA sequences that control cell-specific expression are located upstream of the transcription initiation site. To identify the cis-acting transcriptional control regions within the rat insulin II gene that are responsible for this tissue-specific expression pattern, we constructed a series of 5'-flanking deletion mutants and analyzed their expression in vivo in transfected insulin-producing and -nonproducing cell lines. Pancreatic beta-cell-specific expression was shown to be controlled by enhancer sequences lying between nucleotides -342 and -91 relative to the transcription start site. The rat insulin II enhancer appears to be a chimera, composed of a number of distinct cis-acting DNA elements. Both positive and negative transcriptional regulatory elements appear to be responsible for this cell-type-specific expression. We have shown that expression from one element within the enhancer, which is found between nucleotides -100 and -91, is regulated by both positive- and negative-acting cellular transcription factors. Expression from chimeras containing only the enhancer element sequences from -100 to -91 were active only in insulin-producing cells, indicating that the positive-acting factor(s) required for this activity may be active only in beta-cells. In contrast to the enhancer region, the rat insulin II gene promoter did not appear to require cell-specific transcription factors. Promoter mutants with 5'-flanking sequences extending to nucleotides -90 and -73 were constitutively active in both insulin-producing and -nonproducing cells. These results suggest that rat insulin II gene transcription in pancreatic beta-cells is imparted by a combination of both negative- and positive-acting cellular factors interacting with the gene enhancer.


Subject(s)
Gene Expression Regulation , Insulin/genetics , Islets of Langerhans/metabolism , Regulatory Sequences, Nucleic Acid , Animals , Cell Line , Cricetinae , DNA Mutational Analysis , DNA Restriction Enzymes , Genetic Vectors , Promoter Regions, Genetic , Rats , Ribonucleases
13.
Mol Cell Biol ; 9(5): 1929-39, 1989 May.
Article in English | MEDLINE | ID: mdl-2546054

ABSTRACT

The internal enhancer binding factor (IBF) that specifically binds sequences within the gag gene internal enhancer of Rous sarcoma virus Schmidt-Ruppin A was purified to near homogeneity from BHK cells. The polypeptides that constituted IBF DNA-binding activity were identified by sodium dodecyl sulfate-polyacrylamide gel analysis. As isolated from BHK cells, IBF consisted of two different but related polypeptides. One (IBF alpha) had a molecular weight of 40,000; the other (IBF beta) had a molecular weight of 20,000 and appeared to be a proteolytic product of IBF alpha. The site within the gag gene to which IBF bounds in vitro (internal enhancer site 2; nucleotides 856 to 878 of the Rous sarcoma virus genome) were demonstrated to function as a cis-acting transcriptional stimulatory element both in vivo and in vitro. By using HeLa cell nuclear transcription extracts, purified IBF was found to function as a trans-acting transcription factor that stimulated transcription in vitro. Purified IBF was also demonstrated to be very similar to EBP20 (K. Carlberg, T. A. Ryden, and K. Beemon, J. Virol. 62:1617-1624, 1988), and it may well belong to the same family of DNA-binding proteins.


Subject(s)
Avian Sarcoma Viruses/metabolism , Transcription Factors/isolation & purification , Animals , Avian Sarcoma Viruses/genetics , Base Sequence , Binding Sites , DNA/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/isolation & purification , Enhancer Elements, Genetic , Molecular Weight , Protein Conformation , RNA Polymerase II/genetics , Transcription Factors/genetics , Transcription, Genetic
14.
Mol Cell Biol ; 10(7): 3770-81, 1990 Jul.
Article in English | MEDLINE | ID: mdl-2355922

ABSTRACT

We have previously identified a series of five DNase-I hypersensitive (HS) sites within and around the rat phosphoenolpyruvate carboxykinase (PEPCK) gene. The far upstream region has now been sequenced, and the tissue-specific HS site has been mapped more precisely at 4,800 base pairs upstream of the transcription start site of the PEPCK gene. DNA fragments that include the HS site were cloned upstream of various promoters to test whether these regions modulate transcription of the chloramphenicol acetyltransferase reporter gene. Chloramphenicol acetyltransferase activity was enhanced when the DNA fragment encompassing the upstream HS site was linked to various lengths of the PEPCK promoter or to the heterologous simian virus 40 promoter. This upstream region in conjunction with the proximal promoter, which may contain a tissue-specific element, conferred maximum activation in H4IIE hepatoma cells, which express the endogenous PEPCK gene. When these experiments were performed in XC cells, in which the gene is not expressed, transcriptional activation by the upstream element was still significant. Evidence of a specific protein-DNA interaction, using DNA mobility shift and DNase I footprinting assays, was obtained only when using H4IIE cell nuclear extracts. Competition assay showed that the interacting factor may be similar or identical to the liver-specific factor HNF3. We suggest that this protein factor binds to DNA within the HS site and interacts with the proximal promoter region to control tissue-specific high-level expression of the PEPCK gene.


Subject(s)
DNA-Binding Proteins/metabolism , Enhancer Elements, Genetic , Genes , Phosphoenolpyruvate Carboxykinase (GTP)/genetics , Promoter Regions, Genetic , Transcription, Genetic , Animals , Base Sequence , Cell Line , Cell Nucleus/metabolism , Chloramphenicol O-Acetyltransferase/genetics , Chromatin/physiology , Cloning, Molecular , Deoxyribonuclease I , Gene Expression Regulation , Liver/enzymology , Liver Neoplasms, Experimental , Molecular Sequence Data , Rats , Restriction Mapping
15.
Mol Cell Biol ; 11(10): 4809-21, 1991 Oct.
Article in English | MEDLINE | ID: mdl-1922021

ABSTRACT

We have examined the structure-function relationships of TFIID through in vivo complementation tests. A yeast strain was constructed which lacked the chromosomal copy of SPT15, the gene encoding TFIID, and was therefore dependent on a functional plasmid-borne wild-type copy of this gene for viability. By using the plasmid shuffle technique, the plasmid-borne wild-type TFIID gene was replaced with a family of plasmids containing a series of systematically mutated TFIID genes. These various forms of TFIID were expressed from three different promoter contexts of different strengths, and the ability of each mutant form of TFIID to complement our chromosomal TFIID null allele was assessed. We found that the first 61 amino acid residues of TFIID are totally dispensable for vegetative cell growth, since yeast strains containing this deleted form of TFIID grow at wild-type rates. Amino-terminally deleted TFIID was further shown to be able to function normally in vivo by virtue of its ability both to promote accurate transcription initiation from a large number of different genes and to interact efficiently with the Gal4 protein to activate transcription of GAL1 with essentially wild-type kinetics. Any deletion removing sequences from within the conserved carboxy-terminal region of S. cerevisiae TFIID was lethal. Further, the exact sequence of the conserved carboxy-terminal portion of the molecule is critical for function, since of several heterologous TFIID homologs tested, only the highly related Schizosaccharomyces pombe gene could complement our S. cerevisiae TFIID null mutant. Taken together, these data indicate that all important functional domains of TFIID appear to lie in its carboxy-terminal 179 amino acid residues. The significance of these findings regarding TFIID function are discussed.


Subject(s)
Saccharomyces cerevisiae/genetics , Transcription Factors/physiology , Amino Acid Sequence , Base Sequence , DNA Mutational Analysis , Genetic Complementation Test , Immunoblotting , Kinetics , Molecular Sequence Data , Plasmids/genetics , Promoter Regions, Genetic/genetics , Saccharomyces cerevisiae/growth & development , Structure-Activity Relationship , Transcription Factor TFIID , Transcription Factors/genetics
16.
Ann Acad Med Singap ; 35(1): 33-7, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16470272

ABSTRACT

INTRODUCTION: The aim of this study was to assess toxicity and response in the sequential administration of gemcitabine followed by cisplatin in unresectable or metastatic non-small cell lung cancer. MATERIALS AND METHODS: Twenty-three patients were enrolled in this study. Gemcitabine was given at 1,250 mg/m2 on days 1 and 8, for four 21-day cycles. RESULTS: There were 4 patients with partial responses. 5 patients with stable disease and 10 patients with progressive disease, giving a response rate of 21%. The median time to disease progression was 3.3 months. The median overall survival was 14.6 months. Toxicities graded 3 or 4 included anaemia (13.0%), neutropaenia (13.0%), supraventricular tachycardia (4.3%), and nausea and vomiting (4.3%). CONCLUSION: Although these results show similar efficacy to single-agent treatment regimens, the low toxicity profile and promising survival outcome with this regimen are important points for consideration.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Carcinoma, Non-Small-Cell Lung/drug therapy , Lung Neoplasms/drug therapy , Carcinoma, Non-Small-Cell Lung/physiopathology , Cisplatin/administration & dosage , Cisplatin/therapeutic use , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Deoxycytidine/therapeutic use , Disease Progression , Female , Humans , Lung Neoplasms/physiopathology , Male , Middle Aged , Singapore , Gemcitabine
17.
Hong Kong Med J ; 11(5): 342-50, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16219953

ABSTRACT

OBJECTIVES: To study children with cerebral palsy in Hong Kong, their neuroimpairment, activity limitation, and participation restriction in society. Parents' opinion on current medical and rehabilitation services was also sought. DESIGN: Systematic survey using questionnaires. SETTING: Four associations in Hong Kong: Child Assessment Service, Hong Kong Association for Parents of Children with Physical Disabilities, Association of Parents of the Severely Mentally Handicapped, and Hong Kong Physically Handicapped and Able-Bodied Association. PARTICIPANTS: Parents of children with cerebral palsy. MAIN OUTCOME MEASURES: Neuroimpairment, activity limitation, and participation restriction. RESULTS: Information from 181 children with cerebral palsy was analysed. Among them, 56% were boys. The mean age was 7 years 6 months (standard deviation, 3 years 11 months). The most common diagnostic type was spastic cerebral palsy. Co-morbidities in children with cerebral palsy were common. Limitation in daily activities including mobility and self-care tasks was considerable and this posed great stress to parents when taking care of their children. Children's participation in both social and leisure activities was regarded as a low priority. A high percentage (70%) of parents reported difficulty in travelling. The reasons involved problems in transportation, building access (entry and exit), and attitudes of the general public. These environmental factors restricted the social participation of the children and their families. Over 75% of parents were satisfied with the current medical and rehabilitation services. CONCLUSIONS: Children with cerebral palsy have multiple and complex needs. The findings of this study may serve as a reference for parents, service providers, and policy makers to work in partnership to achieve a more comprehensive health-care service for children with cerebral palsy and to facilitate better integration into the community.


Subject(s)
Activities of Daily Living , Cerebral Palsy/physiopathology , Disabled Children/statistics & numerical data , Adolescent , Adult , Cerebral Palsy/epidemiology , Child , Child, Preschool , Female , Hong Kong/epidemiology , Humans , Infant , Male , Motor Activity , Surveys and Questionnaires
18.
Ann Acad Med Singap ; 34(5): 369-75, 2005 Jun.
Article in English | MEDLINE | ID: mdl-16021227

ABSTRACT

INTRODUCTION: Data on combined modality treatment for locally advanced squamous cell carcinoma of the oesophagus involving Asian patients are limited. MATERIALS AND METHODS: A retrospective study of 56 consecutive patients with this condition treated with concurrent chemoradiotherapy followed by surgery in a single tertiary institution in Singapore was performed. RESULTS: The median overall survival of the entire cohort was 14.1 months [95% confidence interval (CI); range, 8.6 to 19.6 months]. In patients who underwent successful oesophagectomy after chemoradiotherapy (n = 17), the median survival was 27.8 months compared to 9.8 months for those who did not have surgery (n = 39) (P = 0.046, log-rank test). The median time to first relapse for the entire cohort was 16.1 months (95% CI, 7.7 to 24.5 months). The time to first relapse was 23.9 months in the subgroup of patients with successful surgery and 12.1 months in the group which did not (P = 0.147, log-rank test). The high proportion of patients who were medically unfit for surgery or declined surgery may have conferred a selection bias. CONCLUSION: Concurrent chemoradiotherapy followed by surgery is feasible in selected patients. The benefit of adding of surgery to chemoradiotherapy is still controversial and we await the results of randomised controlled trials comparing chemoradiotherapy with surgery versus chemoradiotherapy alone.


Subject(s)
Carcinoma, Squamous Cell/surgery , Esophageal Neoplasms/surgery , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/mortality , Carcinoma, Squamous Cell/radiotherapy , Combined Modality Therapy , Esophageal Neoplasms/drug therapy , Esophageal Neoplasms/mortality , Esophageal Neoplasms/radiotherapy , Esophagectomy , Humans , Retrospective Studies
20.
J Med Microbiol ; 31(1): 21-6, 1990 Jan.
Article in English | MEDLINE | ID: mdl-2296039

ABSTRACT

A chemical marker of bacterial meningitis was sought by comparing derivatives of sterile cerebrospinal fluid (CSF) with cultures of organisms in spinal fluid and artificial media. The technique of gas chromatography-mass spectrometry with selected ion monitoring (GC-MS-SIM) was used, optimised for the analysis of fatty acids. Twenty candidate ions were screened, and an ion of mass: charge ratio (m/e) 268 was chosen for detection in clinical specimens. The origin of this marker is unknown, but it is probably the molecular ion of a C16:1 fatty acid. In 135 clinical specimens of CSF examined, the m/e 268 ion was found to be a useful marker for the common organisms that cause bacterial meningitis, giving a sensitivity of 88% and a specificity of 98%. The method was more rapid and more sensitive than conventional microscopy and culture, but CSF containing coagulase-negative staphylococci, Mycobacterium tuberculosis, Cryptococcus neoformans and some other uncommon pathogens gave inconsistent results. Many organisms produced characteristic ion profiles with multiple-ion monitoring, and this method of chemical analysis holds promise for the rapid diagnosis of bacterial infections to genus or species level.


Subject(s)
Fatty Acids/cerebrospinal fluid , Meningitis/cerebrospinal fluid , Biomarkers/cerebrospinal fluid , Cryptococcosis/cerebrospinal fluid , Cryptococcosis/diagnosis , Gas Chromatography-Mass Spectrometry , Gram-Negative Bacteria/analysis , Gram-Positive Bacteria/analysis , Humans , Meningitis/diagnosis , Mycobacterium Infections/cerebrospinal fluid , Mycobacterium Infections/diagnosis , Staphylococcal Infections/cerebrospinal fluid , Staphylococcal Infections/diagnosis
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