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Biomedical subjects

R Wong

Publications and source records attributed to R Wong.

At least 55 records · Page 3Linked to original sources
PubMed2001

Effects of walnut consumption on plasma fatty acids and lipoproteins in combined hyperlipidemia.

BACKGROUND: Epidemiologic studies show an inverse relation between nut consumption and coronary heart disease. OBJECTIVE: We determined the effects of walnut intake on plasma fatty acids, lipoproteins, and lipoprotein subclasses in patients with combined hyperlipidemia. DESIGN: Participants sequentially adhered to the following diets: 1) a habitual diet (HD), 2) a habitual diet plus walnuts (HD+W), 3) a low-fat diet (LFD), and 4) a low-fat diet plus walnuts (LFD+W). RESULTS: In 13 postmenopausal women and 5 men ( +/- SD age 60 +/- 8 y), walnut supplementation did not increase body weight despite increased energy intake and the LFD caused weight loss (1.3 +/- 0.5 kg; P < 0.01). When comparing the HD with the HD+W, linoleic acid concentrations increased from 29.94 +/- 1.14% to 36.85 +/- 1.13% and alpha-linolenic acid concentrations increased from 0.78 +/- 0.04% to 1.56 +/- 0.11%. During the LFD+W, plasma total cholesterol concentrations decreased by 0.58 +/- 0.16 mmol/L when compared with the HD and by 0.46 +/- 0.14 mmol/L when compared with the LFD. LDL-cholesterol concentrations decreased by 0.46 +/- 0.15 mmol/L when compared with the LFD. Measurements of lipoprotein subclasses and particle size suggested that walnut supplementation lowered cholesterol preferentially in small LDL (46.1 +/- 1.9% compared with 33.4 +/- 4.3%, HD compared with HD+W, respectively; P < 0.01). HDL-cholesterol concentrations decreased from 1.27 +/- 0.07 mmol/L during the HD to 1.14 +/- 0.07 mmol/L during the HD+W and to 1.11 +/- 0.08 mmol/L during the LFD. The decrease was seen primarily in the large HDL particles. CONCLUSIONS: Walnut supplementation may beneficially alter lipid distribution among various lipoprotein subclasses even when total plasma lipids do not change. This may be an additional mechanism underlying the antiatherogenic properties of nut intake.

Coronary Disease↗
PubMed2001

The NH(2)-terminal coiled-coil domain and tyrosine 177 play important roles in induction of a myeloproliferative disease in mice by Bcr-Abl.

Bcr-Abl, a fusion protein generated by t(9;22)(q34;q11) translocation, plays a critical role in the pathogenesis of chronic myelogenous leukemia (CML). It has been shown that Bcr-Abl contains multiple functional domains and motifs and can disrupt regulation of many signaling pathways and cellular functions. However, the role of specific domains and motifs of Bcr-Abl or of specific signaling pathways in the complex in vivo pathogenesis of CML is not completely known. We have previously shown that expression of Bcr-Abl in bone marrow cells by retroviral transduction efficiently induces a myeloproliferative disorder (MPD) in mice resembling human CML. We have also shown that the Abl kinase activity within Bcr-Abl is essential for Bcr-Abl leukemogenesis, yet activation of the Abl kinase without Bcr sequences is not sufficient to induce MPD in mice. In this study we investigated the role of Bcr sequences within Bcr-Abl in inducing MPD using this murine model for CML. We found that the NH(2)-terminal coiled-coil (CC) domain was both essential and sufficient, even though not efficient, to activate Abl to induce an MPD in mice. Interestingly, deletion of the Src homology 3 domain complemented the deficiencies of the CC-deleted Bcr-Abl in inducing MPD in mice. We further demonstrated that the Grb2 binding site at Y177 played an important role in efficient induction of MPD. These studies directly demonstrated the important roles of Bcr sequences in induction of MPD by Bcr-Abl.

3T3 Cells↗
PubMed2001

Provision of phenotype-matched blood units: no need for pre-transfusion antibody screening.

BACKGROUND AND OBJECTIVES: The Hong Kong government is planning to introduce an electronic smart identity card for all seven million citizens in 2003. If the smart card contains the full red cell phenotype/genotype of the individual, it may be possible to transfuse phenotype-matched blood units without pre-transfusion antibody screening. We conducted a feasibility study. DESIGN AND METHODS: Red cell phenotype was determined for 407 donor blood units and 493 patients for whom an antibody screen had been ordered. The computer program selected phenotype-matched blood from the donor stock for the patients according to actual transfusion request. For patients with a positive antibody screen, full crossmatching was carried out with the computer-selected phenotype units. The frequencies of the various red cell phenotypes in the population were calculated from Red Cross data of antigen frequencies. The probabilities of finding at least one unit of phenotype-matched blood from a 300-unit hospital stock and a 4,000-unit Red Cross stock were determined for each phenotype. Cost analysis was performed. RESULTS: Ninety-two out of 493 patients received a total of 395 blood units. The required number of phenotype-matched blood units could be found for 92 patients using a 300-unit pool and for all patients using a 4,000-unit pool. We calculated that phenotype-matched blood could be provided for more than 98% of patients without antibody screening. The total cost of the project is US$ 98 million with potential savings of US$ 14 million per year. INTERPRETATION AND CONCLUSIONS: It is feasible and cost-effective to transfuse patients with phenotype-matched blood without antibody screening using a smart card system.

Blood Group Antigens↗
PubMed2000

Cost effectiveness analysis of intravenous ketorolac and morphine for treating pain after limb injury: double blind randomised controlled trial.

OBJECTIVES: To investigate the cost effectiveness of intravenous ketorolac compared with intravenous morphine in relieving pain after blunt limb injury in an accident and emergency department. DESIGN: Double blind, randomised, controlled study and cost consequences analysis. SETTING: Emergency department of a university hospital in the New Territories of Hong Kong. PARTICIPANTS: 148 adult patients with painful isolated limb injuries (limb injuries without other injuries). MAIN OUTCOME MEASURES: Primary outcome measure was a cost consequences analysis comparing the use of ketorolac with morphine; secondary outcome measures were pain relief at rest and with limb movement, adverse events, patients' satisfaction, and time spent in the emergency department. RESULTS: No difference was found in the median time taken to achieve pain relief at rest between the group receiving ketorolac and the group receiving morphine, but with movement the median reduction in pain score in the ketorolac group was 1.09 per hour (95% confidence interval 1.05 to 2.02) compared with 0.87 (0.84 to 1.06) in the morphine group (P=0.003). The odds of experiencing adverse events was 144.2 (41.5 to 501.6) times more likely with morphine than with ketorolac. The median time from the initial delivery of analgesia to the participant leaving the department was 20 (4.0 to 39.0) minutes shorter in the ketorolac group than in the morphine group (P=0.02). The mean cost per person was $HK44 ( pound4; $5.6) in the ketorolac group and $HK229 in the morphine group (P<0.0001). The median score for patients' satisfaction was 6.0 for ketorolac and 5.0 for morphine (P<0.0001). CONCLUSION: Intravenous ketorolac is a more cost effective analgesic than intravenous morphine in the management of isolated limb injury in an emergency department in Hong Kong, and its use may be considered as the dominant strategy.

Adolescent↗
PubMed2000

Changes in human immunodeficiency virus type 1 virus load during mobilization and harvesting of hemopoietic progenitor cells. Adult AIDS Clinical Trials Group 285 Study Team.

Genetic modification of hemopoietic progenitor cells ex vivo, followed by the infusion of the genetically modified cells into the human immunodeficiency virus-1 (HIV-1) infected donor, has been proposed as a treatment for HIV-1 infection. The current study was undertaken to evaluate the effect of hemopoietic stem cell mobilization and harvesting on HIV-1 replication in persons with HIV-1 infection. Eighteen HIV-1-infected persons received recombinant granulocyte colony-stimulating factor (G-CSF; Filgrastim) 10 microg/kg per day, for 7 days. On days 4 and 5, peripheral blood mononuclear cells were harvested by leukapheresis. The CD4+ lymphocyte count at entry was >500/microL for 6 subjects, 200 to 500/microL for 6 subjects, and <200/microL for 6 subjects. For 9 of 18 subjects, plasma HIV-1 RNA levels increased 4- to 100-fold (>0.6 log(10)) above baseline between days 4 and 7 and returned to baseline by day 27. Significant increases of plasma HIV-1 RNA levels occurred in 5 subjects despite 3-drug antiretroviral therapy. Changes in CD4+ and CD34+ cells during mobilization and harvesting were similar in all subjects whether they had or did not have increased plasma HIV-1 RNA levels. Thus, mobilization and harvesting of bone marrow progenitor cells from persons infected with HIV-1 induced a transient increase in viral replication in some patients but was not associated with adverse effects. (Blood. 2000;95: 48-55)

Adult↗
PubMed2000

Referring physicians' satisfaction with the rapid response radiotherapy programme. Survey results at the Toronto-Sunnybrook Regional Cancer Centre.

For patients with advanced incurable cancer, radiotherapy provides effective palliation and improved quality of life. At the Toronto-Sunnybrook Regional Cancer Centre, the Rapid Response Radiotherapy Programme, a pilot programme in Ontario, was started in 1996 to provide timely palliative radiotherapy. Over 200 patients have been seen annually since 1996. Of the patients referred to the clinic, 90% were treated by palliative radiotherapy. Of those requiring radiotherapy, 80% received treatment on the day of their initial visits, and 90% of the irradiated patients received one to five treatments. The programme has been warmly welcomed by many community medical oncologists and palliative care consultants. Other centres in Canada have followed our example and set up similar clinics. We sent out a survey to all referring physicians to explore the strengths and weaknesses of our programme so as to improve our services. There has been an increase in the utilization of palliative radiotherapy because of the availability of our programme. As a result of this survey we corrected some of our deficiencies. We plan to survey our patients' needs and satisfaction to further improve our programme, since the patients are the ultimate consumers of the service.

Adult↗
PubMed2000

Palliation of bone metastases: a survey of patterns of practice among Canadian radiation oncologists.

BACKGROUND: Palliative radiotherapy constitutes nearly 50% of the workload in radiotherapy. Surveys on the patterns of practice in radiotherapy have been published from North America and Europe. Our objective was to determine the current pattern of practice of radiation oncologists in Canada for the palliation of bone metastases. METHOD: A survey was sent to 300 practicing radiation oncologists in Canada. Five case scenarios were presented. The first three were patients with a single symptomatic site: breast cancer patient with pelvic metastasis, lung cancer male with metastasis to L3 and L1, respectively. The last two were breast and prostate cancer patients with multiple symptomatic bone metastases. RESULTS: A total of 172 questionnaires were returned (57%) for a total of 860 responses. For the three cases with a single painful bone metastasis, over 98% would prescribe radiotherapy. The doses ranged from a single 8 to 30 Gy in ten fractions. Of the 172 respondents, 117 (68%) would use the same dose fractionation for all three cases, suggesting that they had a standard dose fractionation for palliative radiotherapy. The most common dose fractionation was 20 Gy in five fractions used by 84/117 (72%), and 8 Gy in one fraction by 19/117 (16%). In all five case scenarios, 81% would use a short course of radiotherapy (single 8 Gy, 17%; 20 Gy in five fractions, 64%), while 10% would prescribe 30 Gy in ten fractions. For the two cases with diffuse symptomatic bone metastases, half body irradiation (HBI) and radionuclides were recommended more frequently in prostate cancer than in breast cancer (46/172 vs. 4/172, P<0. 0001; and 93/172 vs. 10/172, P<0.0001, respectively). Strontium was the most commonly recommended radionuclide (98/103=95%). Since systemic radionuclides are not readily available in our health care system, 41/98 (42%) of radiation oncologists who would recommend strontium were not familiar with the dose. Bisphosphonates were recommended more frequently in breast cancer than in prostate cancer 13/172 (8%) vs. 1/172 (0.6%), P=0.001. CONCLUSION: Local field external radiotherapy remains the mainstay of therapy, and the most common fractionation for bone metastases in Canada is 20 Gy in five fractions compared with 30 Gy in ten fractions in the US. Despite randomized trials showing similar results for single compared with fractionated radiotherapy, the majority of us still advocate five fractions. The frequency of employing a single fractionation has not changed since the last national survey in 1992. Nearly 70% use a standard dose fractionation to palliate localized painful metastasis by radiotherapy, independent of the site of involvement or tumor type. The pattern of practice of palliative radiotherapy for bone metastases in Canada is different to that reported previously from the US. The reasons why the results of randomized studies on bone metastases have no impact on the patterns of practice are worth exploring.

Bone Neoplasms↗
PubMed2000

High-dose therapy with hematopoietic cell transplantation for patients with central nervous system involvement by non-Hodgkin's lymphoma.

Central nervous system (CNS) involvement by non-Hodgkin's lymphoma (NHL) carries a poor patient prognosis whether it occurs as a primary site of disease or secondarily in patients with systemic disease. In a group of 481 patients undergoing high-dose therapy with hematopoietic cell transplantation (HCT) for NHL, 15 patients (3.1%) were identified with CNS involvement. Two patients had primary CNS lymphoma, and 13 had secondary disease. All patients received intrathecal chemotherapy, and 13 received CNS radiotherapy before transplantation. Fourteen patients received systemic chemotherapy. At the time of transplantation, both patients with primary CNS lymphoma and 8 patients with secondary disease had achieved a complete response, 3 patients had achieved a partial response, 1 had failed induction therapy, and 1 had progression of CNS disease before high-dose therapy. Fourteen patients received carmustine, etoposide, and cyclophosphamide as the preparative regimen, and 1 patient received fractionated total body irradiation instead of carmustine. The 2 patients with primary CNS lymphoma were alive and free of disease, 1 at 1,085 days after HCT and 1 at 3,704 days after HCT. The actuarial 5-year event-free survival (EFS) was 46% +/- 26%, and overall survival (OS) was 41% +/- 28%. The median EFS and OS were 2.2 and 1.5 years, respectively. Three patients experienced symptomatic memory loss or intellectual decline after therapy, 1 patient developed paraplegia, and 1 patient had a thrombotic stroke 20 months after HCT. Despite treatment-related toxicities, 7 patients responding to quality-of-life questions at approximately 1 year after HCT gave their overall quality of life a median rating of 9 out of a possible 10 (range, 6-10). High-dose therapy with autologous HCT can produce extended EFS in patients with secondary CNS lymphoma and possibly in those with primary CNS NHL.

Actuarial Analysis↗
PubMed2000

Identification of three triterpenoids in almond hulls.

Three triterpenoids, betulinic acid, oleanolic acid, and ursolic acid, were isolated as their methyl esters (treatment with diazomethane) from diethyl ether extracts of almond hulls (Nonpareil variety) using flash chromatography and preparative high-performance liquid chromatography. The triterpenoids, which comprised approximately 1% of the hulls, were characterized using chromatographic and spectroscopic methods. These studies demonstrate that almond hulls are a rich source of these triterpenoids, which have reported anti-inflammatory, anti-HIV, and anti-cancer activities.

Chromatography, Gas↗
PubMed2000

Improvement in transfusion safety using a specially designed transfusion wristband.

Fatal haemolytic transfusion reaction due to ABO incompatibility occurs mainly as a result of clerical error. A blood sample drawn from the wrong patient and labelled as another patient's will not be detected by the blood bank unless there is a previous ABO grouping result. We report here the detection of such clerical error by the use of a specially designed transfusion wristband. The wristband has the following special features: (i) once attached, it cannot be removed except by cutting; (ii) it has a pocket containing a transfusion label; (iii) a unique transfusion barcode is printed on each transfusion label and the corresponding wristband simultaneously by computer technology; (iv) a transfusion label removed from the wristband after attachment to the patient has a characteristic tear-mark distinguishing it from one removed prior to attachment. The blood bank only accepted those specimens bearing the tear-marked transfusion labels. All blood units for this patient were labelled with this unique transfusion code together with the patient's details. The nurses counter-checked the transfusion code on the blood units against the transfusion code on the patient's transfusion wristband prior to transfusion. If the blood sample for compatibility testing was drawn from the 'wrong' patient, the intended patient either did not carry a wristband or the transfusion codes did not match at all. Pretransfusion compatibility tests were performed on 2189 patient samples using this procedure. It was well accepted by both ward and blood bank staff. Two potential mismatched transfusions were avoided. These two clerical errors would not have been detected because neither patient had previous ABO grouping results.

Blood Banks↗
PubMed2000

Risk-adapted therapy for clinical stage I-II Hodgkin's disease: 7-years results of radiotherapy alone for low-risk disease, and ABVD and radiotherapy for high-risk disease.

Treatment outcomes were documented for 204 adult patients with clinical Stage I-II Hodgkin's disease who were treated with risk-adapted ABVD (doxorubicin, bleomycin, vinblastine and dacarbazine) and radiotherapy (RT) at the Toronto-Sunnybrook Regional Cancer Centre between 1984 and 1994. Forty-nine patients with clinical Stage I disease (excluding bulky mediastinal presentations) and 50 patients with a combination of clinical Stage IIA disease, age 50 years or less, and favourable pathology (lymphocyte predominant or nodular sclerosing histology) were identified as low risk and treated with RT alone to 35 Gy. One hundred and five high-risk patients were treated with chemotherapy (86 with ABVD) followed by RT to 25 Gy. The 7-year cause-specific, overall and disease-free survivals were 95%, 90% and 75% respectively for the low-risk cohort, and 91%, 90% and 88% respectively for the high-risk cohort. In-field relapses accounted for 50% of the failures in both groups. Sixteen of 24 (67%) patients with RT failure and 6/14 (43%) with combined modality therapy (CMT) failure were salvaged. Twenty-eight per cent of the patients treated with RT and 21% of those treated with CMT developed hypothyroidism by 7 years. Fatal complications were recorded in 6% of the low-risk patients managed with RT and 8% of high-risk patients managed with CMT. Septic death and second malignancy accounted for the majority of treatment-related fatalities. Risk-adapted therapy emphasizing RT alone for selected patients with favourable prognostic factors and CMT based on ABVD provides excellent long-term disease control. Further treatment refinements, including the wider application of CMT with lower doses of chemotherapy and RT, will be required to reduce the rate of fatal complications to more acceptable levels.

Adult↗
PubMed2000

Chinese tonal language rehabilitation following cochlear implantation in children.

Cantonese language rehabilitation in 28 prelingually deaf children who underwent cochlear implantation was evaluated. All patients were implanted with multichannel devices and the operations went smoothly. They all had improved scores on audiological assessments and speech perception tests. The speech evaluation tests included the recognition of sounds, vowels, consonants and tone. Sentence recognition and story comprehension were both improved after training for 2 years. Cochlear implantation is a useful measure for the speech rehabilitation of prelingually profound deaf children when hearing aids are of no benefit. The multichannel implant device is of clinical significance in the rehabilitation of those patients using tonal language.

Child↗
PubMed2000

Reduced mobilization of CD34+ stem cells in advanced human immunodeficiency virus type 1 disease.

Granulocyte colony-stimulating factor (r-met Hu G-CSF; filgrastim; 10 microgram/kg/day for 7 days) was used to mobilize CD34+stem cells into the peripheral blood of human immunodeficiency virus type 1 (HIV-1)-infected individuals and a group of HIV-1-uninfected donors as a measure of immunologic reserve in HIV-1-infected people. G-CSF mobilized CD34+ cells of HIV-1-infected individuals with cell counts >500 CD4+ cells/mm3, as well as in HIV-1-uninfected donors. In contrast, CD34 cell mobilization was significantly blunted in HIV-1-infected individuals with cell counts <500 CD4+ cells/mm3 (<200 cell days vs. >650 cell days, P<.0005, compared with the >500 CD4+ cell cohort). At least 1.75x10(7) CD34 cells were harvested by leukapheresis from patients in each study cohort. CD34+ cell viability and the ability to differentiate precursor cells into myeloid and erythroid progenitor cells were not affected by HIV-1 infection.

Adult↗
PubMed2000

(+)-Catechin in human plasma after ingestion of a single serving of reconstituted red wine.

BACKGROUND: Red wine consumption may decrease the risk of coronary heart disease through the actions of its constituent flavonoids. (+)-Catechin is an abundant flavonoid in red wine. OBJECTIVE: The objective was to determine changes in plasma (+)-catechin concentrations after ingestion of a single, moderate serving of dealcoholized red wine reconstituted with either water (DRW) or water and alcohol (ARW). DESIGN: Nine subjects (5 men, 4 women) ingested, in random order, 120 mL DRW on one day and 120 mL ARW on another day. Both the DRW and ARW contained 35 mg (121 micromol) free (+)-catechin. Blood samples were collected at 0, 0.5, 1, 2, 3, 4, and 8 h. Plasma was analyzed by gas chromatography-mass spectrometry for (+)-catechin after enzymatic release of sulfate and glucuronide conjugates. RESULTS: Calcium ions were needed to effectively hydrolyze (+)-catechin conjugates in plasma containing EDTA. Neither the ARW or DRW nor sex affected the area under the curve at 8 h, the maximum concentration (c(max)), or the time it took for plasma total (+)-catechin to reach maximum concentration (t(max)). Pooled mean (+/-SEM) values for the ARW and DRW were as follows: area under the curve, 306.1 +/- 29.5 nmol*h/L; c(max), 76.7 +/- 7.5 nmol/L; and t(max), 1.44 +/- 0.13 h. The half-life of (+)-catechin in plasma was significantly less (P = 0.038) after ingestion of the ARW (3.17 h) than after ingestion of the DRW (4.08 h). CONCLUSIONS: Increases in plasma total (+)-catechin concentrations were not significantly different after single moderate servings of either the ARW or DRW. Alcohol in the ARW hastened the elimination of (+)-catechin from the plasma compartment. (+)-Catechin elimination may represent excretion or conversion to methylated derivatives.

Adult↗
PubMed2000

Use of the phenylalanine:tyrosine ratio to test newborns for phenylketonuria in a large public health screening programme.

OBJECTIVE: To assess the benefits of using the phenylalanine:tyrosine ratio to screen newborns for phenylketonuria (PKU). SETTING: Data were collected from all newborns in California during a ten month period (n = 404,381). METHODS: Dried blood spot specimens were analysed at nine laboratories. To assure that the results reported from multiple sites were matched accurately, an automated methodology was chosen that included sample processing, analysis, telecommunications, reporting, and information technology. Phenylalanine and tyrosine concentrations were measured independently by continuous flow fluorometry, for which precision, recovery, detection limits, carryover, chemical specificity, reportable range, and number of repeats are reported. RESULTS: In this study, 37% of the newborns were tested at less than 24 hours of age. For this population, using a phenylalanine only cut off of 200 mumol/l, there were 48 recalled infants per case of classic PKU. Using the phenylalanine:tyrosine ratio with a cut off of 1.50, screen positives could be reported with phenylalanine as low as 150 mumol/l and with only 12 recalls per case. CONCLUSIONS: The phenylalanine:tyrosine ratio can be measured accurately at multiple laboratories using two channel chemical analyses. Having applied the methods to the routine clinical screening of a large population, it was confirmed that the clinical sensitivity and specificity of the PKU screening test are higher when the phenylalanine:tyrosine ratio is incorporated into the cut off than when the cut off is based on the phenylalanine concentration alone.

California↗
PubMed2000

Dexamethasone for the prophylaxis of radiation-induced emesis: a National Cancer Institute of Canada Clinical Trials Group phase III study.

PURPOSE: To investigate the efficacy of dexamethasone as a prophylactic antiemetic for patients receiving fractionated radiotherapy to the upper abdomen in a randomized controlled trial. PATIENTS AND METHODS: One hundred fifty-four patients planned to receive fractionated radiotherapy to fields involving the upper abdomen (minimum total dose, 20 Gy; minimum number of fractions, five) were randomized to receive prophylactic dexamethasone (2 mg orally three times a day [tid], starting in the morning of first treatment and continuing until after their fifth treatment) or placebo. The primary end point of the study was the proportion of patients free from emesis during the study period. Secondary end points included a quality-of-life assessment using the core questionnaire of the European Organization for Research and Treatment of Cancer and side effects of dexamethasone therapy in this population of patients. RESULTS: Fifty-four (70%) out of 75 patients receiving dexamethasone had complete protection versus 37 (49%) out of 75 patients on placebo (P = .025). Most emetic episodes occurred during the initial phase of treatment. Although there was no difference in global quality of life between the two sets of patients, patients receiving dexamethasone had less nausea and vomiting and less loss of appetite but more insomnia. CONCLUSION: Dexamethasone 2 mg tid seems to be an effective prophylactic antiemetic in this situation. Side effects were acceptable, but there seemed to be no overall effect on global quality of life.

Abdomen↗