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Biomedical subjects

H Fung

Publications and source records attributed to H Fung.

At least 37 records · Page 2Linked to original sources
PubMed1998

Evaluation of glucose intolerance in pregnancy using biochemical markers of fetal hyperinsulinemia.

We aimed to evaluate gestational impaired glucose tolerance (GIGT) in untreated patients using umbilical cord blood insulin and connecting peptide (C-peptide) concentrations to indicate fetal hyperinsulinemia. A 75 g, 2-hour oral glucose tolerance test, evaluated using WHO criteria, was performed in 722 antenatal patients. Cord C-peptide (p = 0.001) and insulin (p = 0.008) concentrations were significantly higher in patients with GIGT in comparison to those with normal glucose tolerance. The WHO test failed to identify abnormal C-peptide concentrations (p = 0.057), but did identify abnormal insulin concentrations (p = 0.006) and cases where either or both were raised (p = 0.002), with a low Youden's index (range 8.1-11.3) in all 3 cases. A significant biochemical difference exists in patients with GIGT. The WHO criteria for GIGT predict abnormal biochemical outcomes, but they do so poorly.

Biomarkers↗
PubMed1997

Results of high-dose therapy and autologous bone marrow/stem cell transplantation during remission in poor-risk intermediate- and high-grade lymphoma: international index high and high-intermediate risk group.

We have conducted a pilot study to investigate the role of high-dose therapy and autologous bone marrow/stem cell transplantation (ASCT) during first complete or partial remission in 52 patients with poor-risk aggressive lymphoma. There were 42 patients with intermediate-grade or immunoblastic lymphoma who were considered to be high (60%) and high-intermediate risk (40%) groups at diagnosis based on the age-adjusted International Prognostic Index (IPI) and 10 patients with high-grade, SNCCL (small non-cleaved cell, Burkitt's, and non-Burkitt's), who at presentation had poor-risk features defined as elevated serum lactate dehydrogenase level, stage IV, and bulky mass >/=10 cm. The median age was 34 years (range, 16 to 56 years). Thirty-nine were transplanted in first complete remission and 13 in first partial remission after conventional therapy. Conditioning regimens consisted of total body irradiation (TBI) administered as a single fraction 750 cGy in 3 patients and in fractionated doses for a total of 1,200 cGy in 44 patients, in combination with 60 mg/kg etoposide and 100 mg/kg cyclophosphamide. Five patients with prior radiotherapy received 450 mg/m2 carmustine instead of TBI. Stem cell sources were either bone marrow and/or peripheral blood. No in vitro purging was used. All patients engrafted. Two SNCCL patients died of venoocclusive disease at 25 days and acute leukemia at 27 months posttransplantation. There were six relapses at 1.5 to 12.8 months posttransplantation. At a median follow-up of 44 months (range, 1 to 113 months), the estimated 3-year overall survival (OS) and disease-free survival (DFS) for all patients was 84% (95% confidence interval [CI], 70% to 92%) and 82% (95% CI, 68% to 91%), respectively. In the subset of patients with intermediate-grade and immunoblastic lymphoma, the 3-year DFS was 89% (95% CI, 74% to 96%) for all patients, 87% (95% CI, 67% to 96%) for high-risk patients, and 92% (95 CI, 61% to 99%) for high-intermediate risk patients. The 3-year OS and DFS for SNCCL patients were identical at 60% (95% CI, 30% to 84%). These results suggest that high-dose therapy and ASCT during first remission may improve the survival and prognosis of patients with poor-risk intermediate- and high-grade lymphoma. A prospective randomized study comparing high-dose therapy and ASCT with conventional chemotherapy in IPI high-risk patients with aggressive non-Hodgkin's lymphoma should be undertaken.

Adolescent↗
PubMed1997

Inhibition of protein kinase C prevents asbestos-induced c-fos and c-jun proto-oncogene expression in mesothelial cells.

Asbestos and the phorbol ester tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), increase c-fos and c-jun mRNA levels and AP-1 DNA binding activity in rat pleural mesothelial (RPM) cells, a target cell of asbestos-induced mesotheliomas (N. H. Heintz et al., Proc. Natl. Acad. Sci. USA, 90: 3299-3303, 1993). Because protein kinase C (PKC) is the intracellular receptor of phorbol ester tumor promoters and asbestos is a putative tumor promoter in the respiratory tract, we hypothesized that PKC might play a critical role in asbestos-induced cell signaling pathways associated with regulation of proto-oncogenes. Using a panel of PKC antibodies, we identified PKC alpha as the major PKC isozyme in RPM cells. We then pretreated cells with phorbol ester dibutyrate to down-modulate PKC or with calphostin C, a specific PKC inhibitor, to determine if depletion of PKC alpha could block asbestos-induced c-fos/c-jun expression. Quantitation of Northern blots showed that fiber-associated c-fos/c-jun mRNA levels were significantly lower either after PKC alpha down-modulation or pretreatment with calphostin C. In addition, to determine whether tyrosine kinases also were involved in proto-oncogene activation by asbestos, tyrphostin AG82 or herbimycin A was added to RPM cells before exposure to asbestos. These inhibitors decreased crocidolite-induced c-fos but not c-jun levels, suggesting that tyrosine kinases have different regulatory roles in asbestos-induced c-fos versus c-jun signaling pathways. The ability to block induction of asbestos-induced proto-oncogene expression using pharmacological intervention may be important in prevention and treatment of asbestos-induced proliferative diseases including lung cancers, mesothelioma, and pulmonary fibrosis.

Animals↗
PubMed1997

Patterns of 8-hydroxydeoxyguanosine formation in DNA and indications of oxidative stress in rat and human pleural mesothelial cells after exposure to crocidolite asbestos.

Oxidative damage is a proposed mechanism of asbestos-induced carcinogenesis, but the detection of oxidative DNA lesions in target cells of asbestos-induced mesothelioma has not been examined. In studies here, DNA was isolated from both rat pleural mesothelial (RPM) cells and a human mesothelial cell line (MET5A) after exposure in vitro to crocidolite asbestos at various concentrations. DNA was then examined for formation of 8-hydroxydeoxyguanosine (8-OHdG) at 24, 48 and 72 h using HPLC with electrochemical detection. In addition, steady-state mRNA levels of manganese-containing superoxide dismutase (MnSOD) were assessed as an indication of oxidative stress. Whereas RPM cells showed dose-dependent and significant increases in 8-OHdG formation in response to crocidolite asbestos or iron-chelated crocidolite fibers (but not after exposure to glass beads), MET5A cells showed decreases in 8-OHdG. Both cell types exhibited elevations in message levels of MnSOD. In comparison with human MET5A cells, RPM cells exhibited increased cytotoxicity and apoptosis in response to asbestos, as documented by cell viability assays and flow cytometry analysis using propidium iodide. Results in RPM cells indicate that asbestos causes oxidative damage that may result in potentially mutagenic lesions in DNA and/or apoptosis, despite compensatory increases in expression of an antioxidant enzyme.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1997

Dietary patterns amongst ethnic Chinese pregnant women in Hong Kong.

OBJECTIVE: To provide baseline data on the food consumption pattern of ethnic Chinese women in Hong Kong during pregnancy, in order to identify any risk of nutritional imbalance in this population. SUBJECTS AND OUTCOME MEASURES: One hundred and sixty-seven primagravid ethnic Chinese women attending the antenatal booking clinic at the Prince of Wales Hospital in the New Territories region were recruited. Among the study sample, subjects with less than 7 years of residence in Hong Kong were identified as recent immigrants (n = 25), while the remainder (n = 142) were classified as local. Half of the recent immigrants originated on the Chinese mainland and half from Indonesia. The eating patterns of the entire sample were compared with intake recommended in the Taiwan Food Guide. Comparisons were made between local and immigrant regarding age, educational standard and consumption of food from each food group. RESULTS: The median intake of meat and meat substitutes was significantly higher than recommendation. There was no significant difference between actual and recommended intake of fruit but the consumption of dairy products, bread and cereals, and vegetables were all significantly below minimum recommendation. CONCLUSION: The unfavorable dietary pattern reflected that many Chinese pregnant women are still not aware of dietary guidelines and the necessity of modifying their dietary practices in order to achieve the optimal maternal nutrition status. This lack of awareness is more prominently exhibited among the Asian Chinese immigrants.

Adolescent↗
PubMed1997

Role of extracellular signal-regulated protein kinases in apoptosis by asbestos and H2O2.

Stimulation of cell signaling cascades by oxidants may be important in the pathogenesis of pulmonary and pleural diseases. Here, we demonstrate in rat pleural mesothelial cells that apoptotic concentrations of crocidolite asbestos and H2O2 induce phosphorylation and activation of extracellular signal-regulated protein kinases (ERK). Activation of c-jun-NH2-terminal protein kinases (JNK)/stress-activated protein kinases was also observed in response to H2O2. In contrast, asbestos caused more protracted activation of ERK without JNK activation. Both H2O2- and asbestos-induced activation of ERK was abolished by catalase. Moreover, chelation of surface iron from crocidolite fibers or addition of N-acetyl-L-cysteine prevented ERK activation and apoptosis by crocidolite, indicating an oxidative mechanism of cell signaling. The MEK1 inhibitor PD-98059 abrogated asbestos-induced apoptosis, confirming a causal relationship between ERK activation and apoptosis. These results suggest that distinct cell-signaling cascades may be important in phenotypic responses elicited by oxidant stresses.

Acetylcysteine↗
PubMed1997

Personal storytelling as a medium of socialization in Chinese and American families.

The goal of this study was to determine how personal storytelling functions as a socializing practice within the family context in middle-class Taiwanese and middle-class European American families. The data consist of more than 200 naturally occurring stories in which the past experiences of the focal child, aged 2,6, were narrated. These stories were analyzed at 3 levels: content, function, and structure. Findings converged across these analytic levels, indicating that personal storytelling served overlapping yet distinct socializing functions in the 2 cultural cases. In keeping with the high value placed on didactic narrative within the Confucian tradition, Chinese families were more likely to use personal storytelling to convey moral and social standards. European American families did not treat stories of young children's past experiences as a didactic resource but instead employed stories as a medium of entertainment and affirmation. These findings suggest not only that personal storytelling operates as a routine socializing practice in widely different cultures but also that it is already functionally differentiated by 2,6.

Child↗
PubMed1996

Time studies in A&E departments--a useful tool for management.

A time and motion study was conducted in an accident and emergency (A&E) department in a Hong Kong Government hospital in order to suggest solutions for severe queuing problems found in A&E. The study provided useful information about the patterns of arrival and service; the throughput; and the factors that influence the length of the queue at the A&E department. Plans for building a computerized simulation model were dropped as new intelligence generated by the study enabled problem solving using simple statistical analysis and common sense. Demonstrates some potential benefits for management in applying operations research methods in busy clinical working environments. The implementation of the recommendations made by this study successfully eliminated queues in A&E.

Appointments and Schedules↗
PubMed1996

Apoptosis is observed in mesothelial cells after exposure to crocidolite asbestos.

Asbestos causes protracted, dose-dependent increases in steady-state mRNA levels of the proto-oncogenes c-fos and c-jun, and AP-1 DNA-binding activity in normal rat pleural mesothelial (RPM) cells (1). To determine the phenotypic end points of overexpression of these early response genes by asbestos, both cell proliferation and apoptosis were examined in confluent RPM cells exposed to a range of concentrations (1.25 to 10 micrograms/cm2 dish) of crocidolite asbestos for 24 and 48 h. Quantitation of RPM cells pulsed with 5-bromo-2'-deoxyuridine revealed that asbestos caused dose-dependent decreases in cells undergoing DNA synthesis. Decreases in cell proliferation were accompanied by dose-related increases in apoptosis using (1) terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (i.e., ApopTag technique), (2) 4',6-diamidino-2-phenylindole cell staining, and (3) fluorescent-activated cell sorter after incorporation of propidium iodide. Less striking but significant dose-related increases in apoptosis were observed in RPM cells exposed to H2O2 (300 microM), and no apoptosis was seen after exposure of cells to high concentrations (10 micrograms/cm2 dish) of glass beads. Our results are unique in that they demonstrate that asbestos induces apoptosis in mesothelial cells at concentrations eliciting increased expression of the proto-oncogenes c-fos and c-jun.

Animals↗
PubMed1995

Acute monocytic leukemia: a single institution experience.

Using strict FAB criteria, 39 cases of monocytic leukemia were identified in 463 consecutive cases of AML. Patients had a median age of 49 with no sex predominance. Extramedullary disease and hyperleukocytosis were common (54% and 36% of patients respectively). Cytogenetic analysis was successful in 38 of 39 patients; 71% had a cytogenetic abnormality and 42% of these involved chromosome 11; 14 of 16 chromosome 11 abnormalities involved the region of 11q23. Non-chromosome 11 abnormalities tended to occur in older patients and to be associated with a lower platelet count; patients with the translocation 9;11 tended to have a lower white count and a higher incidence of therapy-related leukemia. 35 patients were treated with induction therapy including intensive chemotherapy (n = 33) and allogeneic BMT at presentation (n = 2). Patients who entered remission underwent consolidation chemotherapy, autologous BMT, or allogeneic BMT depending on policies at the time of diagnosis. Of 6 patients who underwent further intensive chemotherapy there is 1 long-term disease-free survivor. 3 of 8 patients undergoing autologous BMT and 2 of 3 patients undergoing allogeneic BMT are long-term disease-free survivors. We conclude that this specific subtype of AML, relatively rare when strict criteria are applied, is associated with unique biologic and clinical features and that the high relapse rate associated with conventional therapy makes new treatment approaches involving stem cell transplantation or immunomodulation necessary.

Adult↗
PubMed1994

Hypothalamo-pituitary effects of RU486: inhibition of progesterone-induced hyperprolactinaemia.

Monkeys given oestrogen priming at physiological levels for at least 1 week become hyperprolactinaemic upon the addition of physiological progesterone administration. Here, using RU486, we test whether that this oestrogen/progestin-induced hyperprolactinaemia results from classical progesterone actions at the hypothalamo-pituitary level. Blood samples were collected daily from study day 1-67. Each monkey (n = 2) received daily injections of 25 micrograms/kg oestradiol benzoate, i.m., on study days 5-60. Progesterone-filled silastic capsules (3 cm) were inserted on study day 14 and removed on day 53. On study days 39-45, each monkey received RU486 (25 mg/day, p.o.). Serum samples were stored at -20 degrees C until assayed for prolactin, oestradiol, progesterone and RU486 by radioimmunoassay. Hyperprolactinaemia was induced in all three monkeys upon insertion of progesterone capsules. Prolactin concentrations fell sharply during RU486 treatment to nadirs some 10-fold less than prior to RU486 treatment. The time series was modelled by the Box-Jenkins autoregressive-integrated moving average (ARIMA) method with progesterone producing a gradual increase in prolactin concentrations and RU486 producing a sudden decrease. Statistically significant effects of progesterone and RU486 were found. Thus, the addition of progesterone to an oestrogenized milieu significantly increased prolactin concentrations, and RU486 fully reversed this effect. This evidence indicates that the progesterone-induced hyperprolactinemia in an oestrogenized milieu results from classical progesterone effects.

Animals↗
PubMed1993

The influence of a glucose load on subsequent carbohydrate metabolism in pregnancy.

Two separate independent exercises comparing 50 g with 75 g and 100 g oral glucose tolerance tests (OGTT) were performed in Chinese pregnant women. We found a significant difference in fasting values between the paired OGTTs when the 100 g test preceded the 50 g test. The fasting glucose levels on the second occasion of testing were significantly lower than on the first testing. The difference was less pronounced when the first glucose load was 75 g and was insignificant when the 50 g test was given first. The blood glucose response to glucose loads was also significantly altered on the second occasion of testing, again in proportion to the size of the first glucose load. We postulate that this influence of glucose tolerance testing on subsequent carbohydrate metabolism results either from sensitization of the pancreatic islet cells or from sensitization of tissues, resulting in increased rate of glucose utilization. We also suggest that an 1,800 Kcal diet represents an increase in carbohydrate load over their normal diet for many of our patients. In patients with mildly deranged OGTT, improvement in the glucose profile on diet may be due to this phenomenon rather than to a decrease in carbohydrate as is believed.

Asian People↗
PubMed1990

A long-term follow-up of postpartum thyroiditis.

To investigate the long-term outcome of postpartum thyroiditis (PPT), 43 patients with PPT and 171 control women were evaluated 3.5 (range 2-4) years postpartum. Ten (23%) PPT patients were hypothyroid compared to none of the controls (P less than 0.001). Factors associated with the development of hypothyroidism were high antimicrosomal antibody titre measured at 16 weeks gestation (P less than 0.01), severity of hypothyroid phase of PPT, multiparity, and a previous history of spontaneous abortion. The presence of microsomal antibody but no PPT in one pregnancy did not prevent the occurrence of PPT in the next pregnancy in two patients and a further five patients had PPT in two successive pregnancies. There was no association between HLA haplotype, family history of thyroid disease, smoking or frequency of oral contraception, and the development of long-term hypothyroidism after PPT. It is concluded that permanent hypothyroidism is an important sequel to PPT and patients with PPT should be followed up appropriately.

Adult↗
PubMed1990

Postpartum thyroid dysfunction and HLA status.

Nine-hundred-and-one women presenting in an antenatal clinic at the 60th week of pregnancy were tested for antithyroid antibodies. A group of 113 antibody-positive women and 108 antibody-negative age-matched controls were HLA typed and followed prospectively at 6-weekly intervals through pregnancy and for 12 months postpartum. Forty-five of the women developed biochemical evidence of postpartum thyroid dysfunction (PPTD) of whom 36 were antibody positive. Compared with a local control population (n = 600), and using multiplex analysis, there was a significant increase in the combinations HLA B8, DR3 and HLA A1, B8, DR3 from 22.5% to 40.0% (P less than 0.02) and from 18.6% to 35.6% (P less than 0.01) respectively in the women who developed PPTD. The well-recognized association of these haplotypes with other organ-specific autoimmune diseases provides further support for autoimmune events being implicated in the development of PPTD.

Autoantibodies↗
PubMed1989

The hormonal environment of post-natal depression.

The incidence of post-natal depression is high, and dramatic changes in steroid hormones and prolactin occur in the post-partum period. In an attempt to correlate these events, 147 mothers, six to eight weeks after delivery of a healthy infant, completed standard psychological tests, including the Edinburgh, Montgomery-Asberg, and Raskin scales. They also provided matched samples of plasma for assay of cortisol, oestradiol, progesterone and prolactin, and saliva for assay of cortisol and progesterone. All steroid concentrations were within the appropriate normal ranges. Of the mothers, 14.9% were depressed on all three scales. Significant correlations were seen between depression ratings and salivary progesterone and prolactin. In bottle-feeders, salivary progesterone was positively associated with depression, whereas in breast-feeders it was negatively associated. Plasma prolactin levels were inappropriately low in depressed breast-feeders. These data indicate that differing therapies may be appropriate for depression in breast- and bottle-feeders.

Adolescent↗
PubMed1989

The use of rating scales to identify post-natal depression.

One hundred and forty-seven mothers were screened for major depression at six to eight weeks post-partum. Using predetermined cut-off points, the Edinburgh Postnatal Depression Scale and the Beck scale were compared in their abilities to identify the 15% of subjects who had major depression according to DSM-III criteria. The sensitivity of Edinburgh scale was 95% and its specificity 93%. The performance of the Beck scale was markedly inferior, with a sensitivity of 68% and specificity of 88%.

Adult↗
PubMed1988

Targeting of porin to the outer membrane of Escherichia coli. Rate of trimer assembly and identification of a dimer intermediate.

Porin, a transmembrane protein in the outer membrane of Escherichia coli, exists in a trimeric structure which is not dissociated during sodium dodecyl sulfate-polyacrylamide gel electrophoresis at 25 degrees C. This unusual stability was utilized in the study of the conformational changes which accompany the targeting of porin to the outer membrane. A delay of 16-44 s between completion of synthesis of a monomer and its assembly into a trimer was found from the ratio of monomers to trimers found in exponentially growing cells. Pulse-chase experiments showed that rapid processing of precursor OmpF molecules was followed by assembly into sodium dodecyl sulfate-resistant oligomers with a half-time of 20 s at 30 degrees C. An intermediate in assembly was isolated by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis below 10 degrees C and was identified as a metastable dimer.

Bacterial Outer Membrane Proteins↗