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Biomedical subjects

E Chiu

Publications and source records attributed to E Chiu.

At least 91 records · Page 5Linked to original sources
PubMed1991

Combined chemotherapy and radiotherapy for lymphomas of Waldeyer's ring.

The management of 47 patients with stage I and II Waldeyer's ring lymphomas was reviewed. Twenty-one of them received radiotherapy only, and the other 26 received combined chemotherapy and radiotherapy. Patients with primary disease in the nasopharynx, high-grade histology or advanced age were associated with poorer survival. Although the complete response rates were similar, the patients receiving combined chemotherapy and radiotherapy had significantly fewer relapses and a better disease-free survival. However, their survivals were similar. The lack of improvement in the overall survival might be due to the effectiveness of salvage chemotherapy in treating some of the radiotherapy failures and the occasional chemotherapy-related mortality.

Adult↗
PubMed1991

A clinico-pathological analysis of seventeen cases of non-Hodgkin's lymphoma involving the orbit.

Seventeen patients with non-Hodgkin's lymphoma involving the orbit were studied. There were 12 males and 5 females and their median age was 53 years. Three cases were classified as stage I, two as stage II and 12 as stage IV. The histology was small lymphocytic type in 4 of the 5 stage I and II cases, and immunophenotyping, confirming their B-cell origin, was performed in two of these cases. All stage I and II patients responded favourably to local radiotherapy alone. The 12 stage IV patients had a marked male predominance and more commonly an intermediate grade histology and T-immunophenotype. Several of the orbital lesions seemed to represent extension of nasal lymphomas. The stage IV patients had a poorer survival than the stage I and II patients but the difference was not statistically significant, probably due to the small number of patients.

Adolescent↗
PubMed1990

Nasal lymphoma. A retrospective analysis of 60 cases.

Sixty cases of nasal lymphomas were reviewed. There were 42 men and 18 women. The median age was 49 years. The histologic types were low grade in four cases, intermediate grade in 33, high grade in seven, and unclassifiable in 16. Thirteen cases had features of polymorphic reticulosis. The immunophenotype was available in 18 cases and a majority of 67% of them were T-cell. Forty-one of them (68%) had clinically localized (Stage I and II) disease which often spread locally to neighboring tissues and they presented predominantly with nasal symptoms. Nasal lymphoma appeared to carry a poor prognosis. Although our patients with clinically localized disease had significantly better prognosis than those with advanced disease, the 5-year survival of Stage I and II patients was only 55%. Chemotherapy did not appear to be more effective than radiotherapy alone in preventing relapses but the patient number was too small to allow a firm conclusion to be made. Patients with advanced disease had even poorer prognosis with a 5-year survival of only 17%. Innovative therapy has to be developed for these patients.

Adolescent↗
PubMed1990

Rearrangement of immunoglobulin, T-cell receptor, and bcl-2 genes in malignant lymphomas in Hong Kong.

The pattern of malignant lymphomas in the Hong Kong Chinese population is characterized by a low incidence of Hodgkin's disease and follicular lymphomas. The authors studied the immunoglobulin (Ig), T-cell receptor (TCR), and bcl-2 gene rearrangement in 62 cases of malignant lymphoma in this population by Southern blot hybridization. Two cases of Hodgkin's disease showed no rearrangement of the Ig and TCR genes. All 42 cases of B-cell lymphoma had Ig heavy chain (JH) rearrangement with or without additional rearrangement of the light chains (C kappa and C lambda). One case of diffuse B-cell lymphoma had additional T-cell receptor beta-chain (C beta) rearrangement. Sixteen of 18 cases of T-cell lymphoma had C beta rearrangement, and one case of T-lymphoblastic lymphoma had additional JH rearrangement. Two of eight (25%) cases of follicular lymphoma but only one of the 34 (2.9%) cases of diffuse B-cell lymphoma had bcl-2 rearrangement that was detected by pFL-1 probe. None of the 62 cases showed bcl-2 rearrangement using the pFL-2 probe. In conclusion, the Ig and TCR gene rearrangement pattern of the lymphomas found in Hong Kong correlates well with the T-cell and B-cell lineage, which is similar to reports in the white population. However, the incidence of bcl-2 gene rearrangement in follicular B-cell lymphoma is lower than that reported in the US but comparable with that in Japan.

Chromosomes, Human, Pair 18↗
PubMed1990

Histologic subtypes and survival of Chinese patients with non-Hodgkin's lymphomas.

The histologic subtypes and survival of 840 Chinese patients with non-Hodgkin's lymphoma (NHL) were reviewed. All cases were classified according to the Rappaport and Kiel systems and the Working Formulation (WF). A low incidence of nodular/follicular lymphomas (12%) was observed. The most common histologic subtypes were diffuse histiocytic, diffuse centroblastic, and diffuse large cell lymphomas, according to Rappaport, Kiel, and the WF, respectively. A high proportion (24%) of the cases were unclassifiable, according to Kiel, because of the precise terms of the classification. The "favorable"-prognosis NHL, according to Rappaport, or the low-grade NHL, according to Kiel and the WF, had a more indolent clinical course. However, except for the nodular mixed (Rappaport) or follicular mixed (WF) lymphomas which appeared to behave like the more aggressive NHL, a plateau was not seen in the survival curves of our patients with other kinds of favorable-prognosis or low-grade NHL, indicating the lack of curative potential of these tumors. The lymphoplasmacytoid lymphoma, according to Kiel, also appeared to have a more aggressive clinical course. A plateau was seen in most of the other survival curves of patients with the more aggressive tumors, indicating the prospect of cure. However, the prognosis of the very aggressive tumors such as the diffuse lymphoblastic and diffuse small noncleaved cell lymphomas, according to the WF, remains very poor with a median survival of less than 10 months.

Adolescent↗
PubMed1990

A unique mental health network for Victorian aboriginal people.

The Victorian Aboriginal Mental Health Network (VAMHN) is a unique mental health programme for Aboriginal people in Australia. The network was set up in 1987. The services and programmes developed include a community consultation service, a psychiatric inpatient unit; and educational, evaluative and research programmes. Utilisation of the network has steadily increased and the demand for both primary and secondary consultations continues to grow.

Adult↗
PubMed1990

Molecular bases of dominant negative and loss of function mutations at the murine c-kit/white spotting locus: W37, Wv, W41 and W.

The proto-oncogene c-kit encodes a transmembrane tyrosine protein kinase receptor for an unknown ligand and is allelic with the murine white-spotting locus (W). Mutations at the W locus affect various aspects of hematopoiesis, the proliferation and migration of primordial germ cells and melanoblasts during development. The original W mutation and W37 are severe lethal mutations when homozygous. In the heterozygous state the W mutation has a weak phenotype while W37 has dominant characteristics. Wv and W41 are weak W mutations with dominant characteristics. We have characterized the molecular basis of these four W mutations and determined their effects on mast cell differentiation by using a fibroblast/mast cell co-culture assay. We show that W37, Wv and W41 are the result of missense mutations in the kinase domain of the c-kit coding sequence (W37 E----K at position 582; Wv T----M position 660 and W41 V----M position 831), which affect the c-kit associated tyrosine kinase to varying degrees. The c-kit protein products in homozygous mutant mast cells are expressed normally, although the 160 kd cell membrane form of the c-kitW37 protein displays accelerated turnover characteristics. The W mutation is the result of a 78 amino acid deletion which includes the transmembrane domain of the c-kit protein. A 125 kd c-kit protein was detected in homozygous W/W mast cells which lacks kinase activity and is not expressed on the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1990

Induction chemotherapy for newly diagnosed acute myeloid leukaemia using a regime containing cytosine arabinoside, daunorubicin and etoposide.

A total of 46 patients with previously untreated acute myeloid leukaemia were treated with an induction regimen consisting of 100 mg/m2 cytosine arabinoside given daily by 18-h i.v. infusion for 7 days, 50 mg/m2 daunorubicin given daily by i.v. bolus injection for 3 days and 75 mg/m2 etoposide given daily by 1-h i.v. infusion for 7 days. In all, 30 patients (67%) went into complete remission and were given further consolidation and maintenance chemotherapy. Of the 31 complete responders, 15 (48%) relapsed. The median disease-free survival of the 31 complete responders and the median overall survival of all 46 patients were 25 and 14 months, respectively. None of the clinical characteristics, which included sex, age, FAB morphology, extramedullary disease and initial WBC count, predicted the clinical response. Myelosuppression was the major toxicity and non-haematological side effects were acceptable. The regimen appeared to have acceptable toxicity, and its efficacy was comparable with that of standard regimens.

Adolescent↗
PubMed1990

Ceftazidime versus imipenem-cilastatin as initial monotherapy for febrile neutropenic patients.

One hundred febrile episodes in 89 neutropenic patients after cytotoxic chemotherapy were randomized to be treated with either ceftazidime or imipenem as initial monotherapy. The clinical characteristics of the two groups of patients were comparable. The response of the fever in patients who received imipenem was significantly better than that in those who received ceftazidime (77 versus 56%, respectively; P = 0.04), especially in those with microbiologically documented infection (81 versus 33%, respectively; P = 0.02). The in vitro susceptibilities and the clinical responses suggested that, with the possible exception of Pseudomonas spp., imipenem was more effective than ceftazidime in treating neutropenic infections caused by both gram-positive and -negative organisms. An additional 23 and 21% of the patients in the ceftazidime and imipenem groups, respectively, responded to the addition of cloxacillin and amikacin following failure of monotherapy. The majority of the treatment failures, relapses, and superinfections were related to resistant infective organisms such as methicillin-resistant Staphylococcus spp. and Pseudomonas spp. or disseminated fungal infections.

Adolescent↗
PubMed1990

Depression in the elderly.

Depression in the elderly is an eminently treatable disease. It may masquerade as a pseudo dementia--a reversible condition with proper treatment. The need for an eclectic approach to management is emphasised and the special needs of the elderly outlined.

Aged↗
PubMed1989

The relationship of human platelet density to platelet age: platelet population labeling by monoamine oxidase inhibition.

The relationship between platelet density and platelet age appears to vary between species with relatively few labeling studies in humans reported. In this study, irreversible monoamine oxidase (MAO) inhibitors were used to biochemically label the circulating platelet population in 15 humans. Platelet samples were then isolated during the 15 days after drug ingestion. The platelets were separated by density on continuous linear Percoll gradients and the density distributions were divided into five fractions containing approximately equal numbers of platelets. Baseline MAO activity was strongly correlated with platelet density. Twenty-four hours after a single dose of tranylcypromine, platelet MAO activities in the density subpopulations were reduced to 14% to 17% of the baseline values. During the first five days after inhibition, the rates of recovery of MAO activity (percentage per day) were inversely proportional to platelet density. The recovery rates in the two most dense fractions were initially slow but increased after five days. Percentage recovery of MAO activity in the least dense fraction was significantly greater than the percentage recovery in the most dense fraction on days 2, 3, 5, and 8 (P less than .01, sign test). These results support the hypothesis that normal human platelets show a small increase in density with age, but they do not exclude the additional possibility that human platelet lifespan is positively correlated with platelet density.

Adult↗
PubMed1988

The use of monoamine oxidase inhibition to estimate megakaryocyte-platelet regeneration time (MPRT).

The megakaryocyte-platelet regeneration time (MPRT) was measured in 16 normal subjects after irreversible monoamine oxidase (MAO) inhibition. When ten subjects were given a single 20 mg dose of Parnate (tranylcypromine) the mean MPRT was 242 +/- 20 hours (linear model) or 212 +/- 22 hours (weighted mean model) with a mean %-linearity of 75 +/- 22%. The renewal of platelet MAO activity was initially retarded for about 2 days, suggesting that inhibition of megakaryocyte MAO had occurred. Six subjects who had taken MAO inhibitors daily for 1-6 months gave longer MPRT values (274 +/- 57 hours (lin.) or 246 +/- 67 hours (w. m.)), but the differences between the groups were not statistically significant. The single-dose MPRT results agree well with those obtained using the irreversible inhibition of cyclo-oxygenase by aspirin, but exceed the platelet life-spans estimated using radiochemical methods by about 24-36 hours. Platelet serotonin levels did not change significantly after a single dose of Parnate, but supine systolic blood pressure rose by 9 +/- 7 mm Hg (p less than 0.01) 24 hours after the dose. Estimation of MPRT by MAO inhibition is a useful alternative to the aspirin method but screening of subjects and clinical supervision is needed to avoid hypertensive complications.

Administration, Oral↗
PubMed1987

Single oral dose pharmacokinetics of tiapride in patients with Huntington's disease.

The pharmacokinetic properties of a single oral dose of 100 mg of tiapride were studied in six patients with Huntington's disease. The results for five patients were consistent with a two compartment open model. Peak plasma concentrations were observed within 2 h following drug administration with a mean value of 0.92 micrograms/ml being recorded. The drug was rapidly eliminated as unmetabolised tiapride in the urine, 51% of the dose was recovered in 24 h. The plasma elimination half-life was 5.3 h and the average apparent plasma clearance was 16.6 l/h.

Administration, Oral↗
PubMed1987

Platelet monoamine oxidase activity in patients with Huntington's disease.

1. Platelet monoamine oxidase (MAO) activity was investigated in 30 patients with Huntington's disease and compared with the activity in a control group. 2. Significantly elevated activity was found in the patients (P less than 0.05; t-test) when same sex contrasts were carried out to account for the well known influence of sex on MAO activity. 3. The mean MAO activity in male patients was 23.5 +/- 6.0 nmol/mg protein per h and female patients was 29.5 +/- 8.9 nmol/mg protein per h using tyramine as the substrate. 4. The possible influence of environmental factors on the results is discussed.

Adolescent↗
PubMed1985

Failure of an alkalophilic bacterium to synthesize ATP in response to a valinomycin-induced potassium diffusion potential at high pH.

Starved whole cells of the obligately alkalophilic Bacillus firmus RAB synthesize ATP upon addition of L-malate at pH 9.0 as expected of an aerobic organism that grows oxidatively on nonfermentable carbon sources at pH values as high as 11.0. The current study was a detailed examination of the perplexing inability of such cells to exhibit ATP synthesis in response to a valinomycin-mediated potassium diffusion potential at pH 9.0. While there were minor differences in the patterns of generation of the potential and the proton influx that accompanies its generation in the three different buffering systems employed, the magnitude of the transmembrane electro-chemical potential of protons was at least as high as pH 9.0 as at pH 7.0. Nevertheless, a diffusion potential consistently energized ATP synthesis at pH 7.0 but not at 9.0; these findings were independent of the presence or absence of Tris or of Na+. By contrast, the artificial electron donor ascorbate, in the presence of phenazine methosulfate, energized ATP synthesis by the starved whole cells at both pH values. The same phenomenon, i.e., efficacy of a respiration-derived potential but not of a diffusion potential at pH 9.0, was demonstrated in ADP + Pi-loaded membrane vesicles. On the other hand, electrogenic Na+-coupled solute transport could be energized by both ascorbate/phenazine and methosulfate and a diffusion potential in the vesicles at pH 9.0. The results are discussed in connection with models of a localized path of proton flow between proton pumps and the ATP synthase.

Adenosine Diphosphate↗