Differential effects of photoactive furanyl compounds on virus functions.
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Alkaloids↗
Biomedical subjects
G C Chan
Publications and source records attributed to G C Chan.
Non-use and cessation of cannabis use: neglected foci of drug education.
Analysis of responses from a large sample of students (grades 7-13) indicated that a large proportion of students reported never having tried cannabis, and the majority of those who had tried the drug reported no longer using it. Multivariate analyses, employing Multiple Classification Analysis procedures, identified those variables most strongly associated with initially trying cannabis and with discontinuing its use. These results indicated that some variables had a similar relationship to these two aspects of cannabis use, but other variables were related exclusively either to trying cannabis or to continuing its use. Implications for education and other preventive interventions are highlighted.
Adolescent↗
Developmental and generational trends in alcohol, cannabis and tobacco use--a ten year cohort analysis.
Six surveys of drug use (including alcohol) among Ontario (Canada) students (grades 7-13) were conducted between 1968-1979. Cohort analyses identified significant increases in the prevalence and incidence of alcohol and cannabis use for all cohorts with, however, some moderation of cannabis use in recent years within the oldest cohort. Recent tobacco use has shown a reduction in the earlier strong trends towards increased use. Developmental influences on drug use were stronger than generational influences. Implications for preventive intervention are discussed.
Adolescent↗
An evaluation of two school-based alcohol education programs.
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Adolescent↗
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↗
Refractory anemia with ringed sideroblasts in children: two diseases with a similar phenotype?
Three pediatric patients with refractory anemia with ringed sideroblasts (RARS) are presented. Bone marrow aspirates were examined using Romanowsky and Prussian blue iron stains in all three patients, and electron microscopic analysis was performed in one patient. All three patients had cytogenetic analysis of the bone marrow. Other studies included analysis of serum iron, total iron-binding capacity, ferritin, copper, vitamins B6 and B12, and folate levels. Antibody titers to Parvovirus, HIV, and other viruses were measured. The patients had contrasting clinical courses. Patients 1 and 2 had dysplastic hematopoietic features and cytogenetic findings (with either partial or one allele loss of chromosome 7), suggestive of myelodysplastic syndrome. Patient 1 experienced acute myeloid leukemia (AML) and had a good response to AML-directed therapy. Patient 2 had prolonged cytopenias and underwent bone marrow transplantation (BMT). Patient 3 had features suggestive of refractory anemia associated with mitochondrial cytopathy, including normal cytogenetics with pronounced vacuolization of marrow precursors. His anemia regressed spontaneously a few months after diagnosis. These patients represent two subgroups of pediatric RARS. Patients with the myelodysplastic syndrome (MDS) type may progress to cytopenias or leukemia and may require aggressive therapy; the type is characterized by clonal cytogenetic findings. The non-MDS type, which may relate to mitochondrial cytopathy, often shows spontaneous regression and requires only supportive treatment; it has normal cytogenetic findings.
Adolescent↗
Prevalence of hepatitis C infection in Hong Kong.
A study of a cross-section of the Hong Kong Chinese population was done to investigate the seroprevalence of hepatitis C. Healthy subjects were random visitors of a health exhibition, while clinical subjects were recruited from an outpatient liver disease clinic, sexually transmitted disease clinics, dialysis centres and drug rehabilitation centres. A total of 910 subjects were tested. The assay kits were from Abbott and Ortho laboratories. Of the general population, 0.5% was found to be positive for antibody to hepatitis C (anti-HCV). Suspected chronic non-A non-B patients, parenteral drug abusers and haemophiliacs shared a common high (up to 70%) prevalence of anti-HCV. Sexual partners of index patients, homosexuals and female prostitutes as well as hepatitis B carriers had 0% prevalence. It was concluded that parenteral and blood product exposures were the two main risk factors for hepatitis C.
Adolescent↗
Mono-arthritis in a chronic hepatitis B patient after alpha-interferon treatment.
A 28 year old woman with hepatitis B (HB) related chronic active hepatitis was treated with a 12 week course of alpha-interferon (alpha-IFN). She developed acute mono-arthritis 1 week after completion of treatment. Her rheumatoid factor (RF) was positive before alpha-IFN and fell steadily during therapy. This was followed by a rebound of RF level with the associated arthritis occurring 1 week after completion of the course of alpha-IFN. In absence of any medication RF gradually fell and became negative at the end of 1 year. This observation is thought to be related to the immunomodulatory effect of alpha-IFN either directly on RF production or indirectly through the control of hepatitis.
Adult↗
Multidisciplinary management of osteosarcoma: experience in Hong Kong.
All pediatric osteosarcomas treated in our hospital between 1985 and 1995 were reviewed. There were 26 patients, 15 males and 11 females, aged 20 or less at diagnosis. All had limb primaries. Nineteen patients had localized disease and seven presented with metastases. Intensive multiagent chemotherapy was given both pre- and postoperatively. Most patients were treated with the Rosen T10 regimen or its modifications. Only one patient had limb salvage surgery; all others had amputation. With a median follow-up of 74 months, the 5-year disease-free survival among patients with localized disease was 65.2%. Being female and having a high 6-hour postinfusion methotrexate level with a median level greater than 700 mumol/L were good prognostic factors. Three of the seven patients with metastatic disease were alive at 21, 26, and 140 months after diagnosis. All of them had lung secondaries. Survival rates achieved in our center were comparable to those reported in literature. However, our amputation rate was high and further development in expertise for limb salvage treatment is a goal.
Adolescent↗
Prevention of beta-thalassemia major by antenatal screening in Hong Kong.
The thalassemias are common in Hong Kong. One of the severe forms, beta-thalassemia major, has been preventable locally by antenatal screening since 1983. Yet new patients are still being diagnosed. In this retrospective study, 34 children with severe beta-thalassemia syndromes were diagnosed in two major public hospitals between 1990 and 1996. They included one pair of identical twins and two pairs of siblings. Twenty-seven (79%) had homozygous beta-thalassemia and seven (21%) had beta E thalassemia. All but four (12%) were transfusion dependent. Fifty-five (89%) parents had been evaluated for their thalassemia status. Forty-eight had beta-thalassemia traits and seven were hemoglobin E carriers. The reasons for the birth of these children with severe beta-thalassemia syndromes were (1) late or no antenatal visit (n = 8, 24.2%), including three cross-border deliveries in which the pregnant mothers came from mainland China to Hong Kong for confinement, (2) lack of maternal screening (n = 13, 39.4%), (3) lack of paternal screening (n = 7, 21.2%), (4) parental refusal (n = 3, 9.1%), and (5) unknown (n = 2, 6.1%). These findings suggest that several factors undermine the effectiveness of antenatal screening for prevention of thalassemias. Many medical practitioners and the general public are still not aware of the screening procedures. The migration of population from mainland China to Hong Kong may result in the birth of many more children with beta-thalassemia major.
Female↗
Enhanced hippocampal CA1 LTP but normal spatial learning in inositol 1,4,5-trisphosphate 3-kinase(A)-deficient mice.
To define the physiological role of IP(3)3-kinase(A) in vivo, we have generated a mouse strain with a null mutation of the IP(3)3-kinase(A) locus by gene targeting. Homozygous mutant mice were fully viable, fertile, apparently normal, and did not show any morphological anomaly in brain sections. In the mutant brain, the IP4 level was significantly decreased whereas the IP3 level did not change, demonstrating a major role of IP(3)3-kinase(A) in the generation of IP4. Nevertheless, no significant difference was detected in the hippocampal neuronal cells of the wild-type and the mutant mice in the kinetics of Ca2+ regulation after glutamate stimulation. Electrophysiological analyses carried out in hippocampal slices showed that the mutation significantly enhanced the LTP in the hippocampal CA1 region, but had no effect on the LTP in dentate gyrus (DG). No difference was noted, however, between the mutant and the wild-type mice in the Morris water maze task. Our results indicate that IP(3)3-kinase(A) may play an important role in the regulation of LTP in hippocampal CA1 region through the generation of IP4, but the enhanced LTP in the hippocampal CA1 does not affect spatial learning and memory.
Animals↗
Consistencies in self-reported drug use among students in Ontario (Canada).
A survey of drug use, carried out in 1981 by means of a self-reported anonymous questionnaire administered to a stratified probability sample of 4,306 school students in grades 5, 7, 9, 11 and 13 in Ontario, Canada, found consistent patterns in the use of drugs, including infrequently used illegal drugs such as heroin. Consistency of drug use was more apparent in the school grades with greater prevalence rates of drug use. Drug use was unevenly distributed and was localized within a relatively small proportion of all schools and geographical areas covered. Among the 17 categories of substances studied, the least frequently used substances were most localized. The study shows a general absence of misrepresentation of drug use by students, which corroborates findings reported by other researchers who have indicated that the problems of reliability and validity of self-reported drug use appear to be more related to difficulties in recalling and self-defining drug use than to its deliberate misrepresentation. The evidence presented in the article suggests that data on self-reported student drug use, as found in this and similar surveys, can be accepted with reasonable confidence.
Adolescent↗
Trends in the prevalence of alcohol and other drug use among Ontario students: 1977-1983.
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Adolescent↗