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Biomedical subjects

V Chan

Publications and source records attributed to V Chan.

205 records · Page 12Linked to original sources
PubMedDate not supplied

Detection of immunoglobulin gene rearrangement in B-cell lymphomas by polymerase chain reaction gene amplification.

This is a report on our attempt to use polymerase chain reaction (PCR) to detect rearrangement of the immunoglobulin gene in the tissue specimens obtained from 30 patients with non-Hodgkin's lymphomas. There were 20 B-cell lymphomas and 10 T-cell. All 20 B-cell lymphomas but none of the 10 T-cell lymphomas had JH rearrangement by Southern analysis. Two pairs of primers (V670/OL-4 and VH26/OL-4) were designed to amplify the CDR3 region of the immunoglobulin gene heavy chain. The PCR analysis was positive using either one or both pairs of primers in 11 of the the 20 cases (55 per cent) of B-cell lymphomas which all had positive rearrangement by Southern analysis. The two pairs of primers seemed to produce complementary results as the specimens may be positive to one pair but negative to the other. The false negative rate of 45 per cent is however much higher than the respective figures of 18 per cent and 0 per cent observed in our patients with acute lymphoblastic leukemia and chronic lymphocytic leukemia in a previous study. Peripheral blood and bone marrow biopsy specimens obtained at the time of initial diagnosis were available from 10 patients with B-cell lymphomas whose lymph node biopsy specimens at the time of diagnosis were positive by both Southern analysis and PCR. All these peripheral blood and marrow specimens had no microscopic evidence of involvement by lymphoma cells and JH rearrangement was not detected by Southern analysis. However, rearranged bands identical to that of the lymph node biopsy specimen were detected by PCR in the peripheral and marrow blood of one of them. This PCR technique has been shown to have a sensitivity of 0.1 per cent in our previous report and may be more useful than morphology alone or Southern analysis in detecting minimal lymphomatous involvement in the peripheral blood and bone marrow at the time of initial diagnosis. Further clinical correlation is required to confirm the finding.

Base Sequence↗
PubMedDate not supplied

Evaluation of a prenatal screening procedure for beta-thalassaemia carriers in a Chinese population based on the mean corpuscular volume (MCV).

Haemoglobin A2 (HbA2) levels were determined on 25 beta-thalassaemia carriers by the microcolumn method and were found to range from 4.5-7.2 per cent (mean 5.2 +/- 0.82 S.D.). The haemoglobin level (Hb), mean corpuscular volume (MCV), plasma ferritin and HbA2 levels were measured on a further 299 consecutive Chinese pregnant women at a gestation of less than 24 weeks. 18 patients (6 per cent) had HbA2 level greater than 4.5 per cent and were diagnosed to be beta-thalassaemic carriers. It was observed that all these patients had a MCV below 75 fl. If this level is selected in a screening procedure based on measurement of MCV alone all beta-thalassaemia carriers could be detected and 11 per cent of the population screened would require HbA2 estimation. At a lower cut-off level of 70 fl, 8 per cent of the population screened would require HbA2 measurement (a decrease of 27 per cent) but the detection rate will be lowered considerably (83 per cent). The high false positive rate at all cut-off levels of MCV was largely due to the prevalence of iron deficiency anaemia in the population. Estimation of plasma ferritin level in patients with low MCV will reduce this false positive rate, but there will be a considerable delay in diagnosis in patients with concomitant iron deficiency and beta-thalassaemia. The presence of iron deficiency in beta-thalassaemia carriers did not reduce their HbA2 level below the diagnostic range in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocyte Indices↗
PubMedDate not supplied

Sibling HLA-matched cord blood transplant for beta-thalassemia: report of two cases, expression of fetal hemoglobin, and review of the literature.

PURPOSE: A program of cord blood stem cell (CBSC) transplants for patients with beta-thalassemia major was initiated in conjunction with the prenatal diagnostic service in 1994. Two patients who received HLA-matched related CBSC transplants with posttransplant fetal hemoglobin (HbF) expression are described and the literature is reviewed. PATIENTS AND METHODS: After screening 12 pregnancies, matched sibling CBSC transplants were performed for 2 girls with beta-thalassemia major when they were 3.8 and 2.2 years old, respectively. Their HbF was assayed serially. RESULTS: The nucleated cell counts/kg were 11.4 x 10(7) and 6.2 x 10(7), which engrafted on days 19 and 24, respectively. The children are now transfusion-independent at 3 years and 1.2 years posttransplant. Their HbF levels showed a rapid rise posttransplant and reached peak levels of 37.2% and 42.2% on day 83 and day 88, respectively. The HbF levels declined to 1.0% and 3.8% on day 581 and day 305, respectively. Nine other sibling CBSC transplants for thalassemias have been reported with an engraftment rate of approximately 50%. Graft rejection was related to insufficient CBSC number in one. CONCLUSIONS: HbF levels in patients with beta-thalassemia major after CBSC transplants could be influenced by many factors, including reactivation of HbF synthesis, intrinsic rate of Hb switching of CBSC, and mixed chimerism.

Female↗
PubMedDate not supplied

Valve replacement surgery complicated by acute renal failure--predictors of early mortality.

BACKGROUND: Acute renal failure (ARF) is a serious complication of valve replacement surgery. The aim of this study was to determine the predictors of early mortality and if causative factors are preventable. METHODS: In the 25-year period between 1977 and 2002, 255 (2.6%) of 9721 patients (11,007 operations), who had valve replacement surgery, were managed for ARF with dialysis. The mean age of the patient population was 67.1 +/- 11.6 years (range 24 to 87 years, median 70.3 years). Fifty preoperative, operative, and postoperative risk factors were assessed as predictors of early mortality by univariate and multivariate modeling. RESULTS: The early mortality was 25.1% (64 patients). The predictors by univariate analysis were: New York Heart Association class (p = 0.001); ASA within 5 days (p = 0.030); cardiogenic shock (p = 0.010); infection--perioperative sepsis and preoperative endocarditis (p = 0.000); intraoperative stroke (p = 0.003); status--emergent (p = 0.000); mitral valve replacement (p = 0.040); ischemic (X-clamp) time >120 minutes (p = 0.020); cardiopulmonary bypass time >180 minutes (p = 0.000); surgical time >360 minutes (p = 0.000); surgical hemorrhage (p = 0.020); acute respiratory distress syndrome (ARDS) (p = 0.040). Multivariate predictors were urgent status of operation, odds ratio (OR) 0.3 (p = 0.029); emergent status of operation, OR 5.8 (p = 0.034); ischemic (X-clamp) time >120 minutes, OR 4.4 (p = 0.030); surgical time >360 minutes, OR 6.3 (p = 0.019); surgical hemorrhage, OR 5.1 (p = 0.003); perioperative nosocomial sepsis, OR 3.8 (p = 0.006); and preoperative endocarditis, OR 4.4 (p = 0.004). CONCLUSIONS: Early mortality from ARF in valve replacement surgery is related to emergent status, ischemic and surgical times, surgical hemorrhage, and nosocomial infection/preoperative endocarditis. Among the variables assessed, preoperative renal insufficiency, unstable angina/recent myocardial infarction <6 weeks, and concomitant coronary artery bypass were not predictive. The evaluation of predictors of ARF requires further extensive assessment.

Acute Kidney Injury↗
PubMedDate not supplied

Implementing nursing diagnoses within the context of King's conceptual framework.

The use of nursing conceptual frameworks and nursing diagnoses is generally acknowledged to hold immense promise for the further development of nursing's scientific base. The nursing profession to date has failed to link the two, thus diminishing their impact. A large community hospital in Canada adopted King's Conceptual Framework for Nursing Practice and advocated the use of NANDA's nursing diagnostic statements as the manner by which patient needs or problems would be identified. Nurses, however, required assistance in identifying more clearly the connection between the theoretical base and nursing diagnoses. During stage one of this project a tool was designed that categorized NANDA's nursing diagnoses according to the concepts and systems of King's conceptual framework. The difficulties encountered in categorizing the nursing diagnoses are discussed and the categorization system is outlined. The utility of the tool was tested during stage two. A total of 25 nurses were asked to describe how they arrived at a particular nursing diagnosis before and after using the categorization tool. Criteria were used to indicate whether a connection had been made between the formulation of the nursing diagnosis and King's conceptual framework throughout the nurse's thought processes. The results indicated that nurses could make a connection between NANDA's nursing diagnoses and King's framework with the assistance of the categorization tool.

Classification↗
PubMedDate not supplied

Closed-circuit TV: an effective patient education tool.

Patient education is well accepted to be an integral component of professional nursing practice. Although most nurses value patient teaching, the reality of the nursing shortage demands that innovative strategies be utilized to plan, implement and evaluate in-hospital patient education programs. Advances in computer technology have made closed-circuit television (CCTV) an attractive option for hospitals to fulfil their patient education mandate. As a delivery system, CCTV can be of considerable value. But as is true of other instructional media used to supplement educational efforts, CCTV also provides many traps that can limit its effectiveness. The biggest danger is the misuse of the tool by attempting to replace rather than supplement human interaction during the education process. This paper provides practical suggestions for the creative use of CCTV as a teaching tool to enhance patient education efforts. Pitfalls inherent in planning and implementing a CCTV system will be discussed.

Humans↗