Search PubMed⌕ Search

Biomedical subjects

R Liang

Publications and source records attributed to R Liang.

At least 163 records · Page 9Linked to original sources
PubMed1998

Mutation of the 5' noncoding region of the BCL-6 gene in low-grade gastric lymphoma of the mucosa-associated lymphoid tissue.

BCL-6 gene rearrangement and hypermutations were investigated in four Hong Kong Chinese patients with low-grade gastric lymphoma of the mucosa-associated lymphoid tissue (MALToma). The former was studied by Southern analysis and the latter by the technique of polymerase chain reaction and denaturing gradient gel electrophoresis. BCL-6 gene rearrangement was not detectable in any of the four cases. However, mutations at both the E1.11 and E1.12 segments of the 5' noncoding region of the BCL-6 gene were found in two patients. This preliminary observation suggests that the mutations of the 5' noncoding region of the BCL-6 gene rather than gene rearrangement may be playing a more important role in the tumorigenesis of low-grade gastric MALToma. Further confirmation of this finding by studying a larger number of patients will be required.

Aged↗
PubMed1998

Near tetraploidy in three cases of acute myeloid leukemia associated with mediastinal granulocytic sarcoma.

Granulocytic sarcoma (GS) is a rare manifestation of acute myeloid leukemia (AML), blastic transformation of chronic myeloid leukemia, and the myelodysplastic syndromes. The mediastinum is an unusual site of presentation. We report a series of three female patients with mediastinal GS. They were characterized by the presence of large and bizarre blast cells and near tetraploidy on cytogenetic analysis. All three patients responded poorly to chemotherapy. Near tetraploid AML is a rare entity, usually present in male patients, and has not been associated with GS. The clinical and pathological similarities in these three cases suggest a distinct category of poor-risk AML for which more intensive treatment is needed.

Adult↗
PubMed1998

A novel mutation of Arg306 of factor V gene in Hong Kong Chinese.

We have analyzed 83 unrelated Hong Kong Chinese for the presence of genetic variants of factor V gene. Forty-three of them had a history of deep vein thrombosis. The DNA sequence variations of exons 7, 10, and 13, where the codons for Arg306, Arg506, and Arg679 are located, respectively, were studied by denaturing gradient gel electrophoresis. The G1691-->A (Arg 506-->Gln) mutation in exon 10 was not detectable in any of the 83 subjects. However, a high allelic frequency for the G1628-->A (Arg 485-->Lys) substitution was detectable in the same exon. We have also identified a novel DNA sequence mutation (A1090-->G) in exon 7 that resulted in Arg 306-->Gly substitution in 2 thrombotic patients and 1 nonthrombotic subject. Fresh blood samples were available from one of them for analysis of activated protein C resistance and the result was negative. Variation of DNA sequence was not found in exon 13 in any of our 83 subjects. The results of this study showed that, although the Arg 506-->Gln mutation was rarely found in the Hong Kong Chinese population, a different mutation site such as A 1090-->G in exon 7 of the factor V gene (Arg 306) may be of clinical importance.

Arginine↗
PubMed1998

Mantle cell lymphoma in the Chinese: clinicopathological features and treatment outcome.

We report the clinical, molecular, and immunohistological findings of 20 Chinese patients with mantle cell lymphoma diagnosed over a 10-year period. The disease affected mainly elderly patients (median age, 65.5 years) with a male predominance (M/F, 3/1). Eighty percent presented with advanced stage III/IV disease but only 25% had B symptoms. Eighty-five percent had extranodal disease at presentation. Complete remission (CR) and partial remission (PR) were achieved in 45% and 40% of the patients, respectively. There was no difference in the CR rate for patients treated with anthracycline-containing or nonanthracycline-containing regimens (43% and 50%, P = 0.67). Disease progression or relapse was observed after a median of 26 months in patients who initially responded to treatment. Extranodal relapse occurred in the central nervous system (n = 1), bone marrow (n = 1), pleura (n = 2), orbit (n = 2), and the gastrointestinal tract (n = 3). The median overall survival (OS) was 52 months but there were no long-term survivors. This was not different from the median OS of 53 months of patients with diffuse large cell (DLC) lymphoma treated in the same center over the same period (log rank, P = 0.76). Of the 12 patients who were tested for bcl-1 rearrangement by polymerase chain reaction (PCR), five (42%) were positive for rearrangement in the major translocation cluster (MTC) region. The median OS rates were 45 months and 63 months for PCR positive and negative patients, respectively (P = 0.97). In conclusion, MCL is a disease mainly of the elderly in the Chinese with a male predominance and most had advanced-stage disease and extranodal involvement at presentation. Clinicopathologic features and treatment outcome were similar to Caucasian patients, in that the disease combined the aggressive nature of DLC lymphoma and the incurability of low-grade lymphoma.

Aged↗
PubMed1998

Allogeneic bone marrow transplantation for severe aplastic anemia: the Hong Kong scenario.

Severe aplastic anemia (SAA) is a disease associated with high mortality. For young patients with HLA identical siblings, allogeneic bone marrow transplantation (BMT) offers the best chance of cure. Favourable results have also been reported using immunosuppressive therapy (IST). Transplantation is usually favoured for patients below 45 years of age. We report our experience of 11 allogeneic and one syngeneic BMT for adult Chinese patients with SAA, over a 4-year period from 1991 to 1995. Ten of the 12 (83 per cent) patients had received and failed prior IST including anti-thymocyte globulin (ATG) before being referred for BMT. Neutrophil and platelet engraftment was successful in 11 of them (92 per cent) and nine were completely transfusion independent after transplantation. Their overall 3-year survival was 67 per cent. The compromised overall result was due to a number of cases transplanted after a long time delay. No patient transplanted beyond 3 years from the initial time of diagnosis of SAA achieved long-term marrow engraftment, and they all eventually succumbed. On univariate analysis, a longer time delay and hence a larger amount of blood products exposure, were highly significantly statistically associated with inferior marrow engraftment and patient survival. Other factors including age, iron status, infused cell dose and the conditioning protocol were not found to significantly affect engraftment and survival. Graft versus host disease was clinically mild or absent in most patients. This may be related to ethnicity or previous ATG exposure. In conclusion, early allogeneic BMT was a safe and effective treatment in our small series of patients with SAA failing IST.

Adolescent↗
PubMed1998

CEOP treatment results and validity of the International Prognostic Index in Chinese patients with aggressive non-Hodgkin's lymphoma.

From 1991 to 1997, we have treated 78 newly diagnosed patients with aggressive non-Hodgkin's lymphoma with a modified CHOP regimen in which epirubicin (60 mg/m2) was used in place of doxorubicin (50 mg/m2), i.e. CEOP (cyclophosphamide, epirubicin, vincristine and prednisolone). The median age was 41 years (range: 17 to 67). Sixty-four (82 per cent) had diffuse large cell (Working Formulation category G) histology. The median LDH level was 453 u/l. Thirty-three (42.3 per cent) and 45 (57.7 per cent) had stage I/II and stage III/IV disease, respectively. Fifty-five of 78 (71 per cent) CEOP-treated patients achieved CR, and the projected DFS and OS were both 65 per cent. In an earlier cohort of patients (from 1985-1991) treated with second or third-generation chemotherapy regimens (m-BACOD, MACOP-B, ProMACE-CytaBOM), CR was achieved in 95/123 (77 per cent) patients and the projected DFS and OS were 62 per cent and 55 per cent. There was no significant difference in the clinical characteristics, CR rates (p = 0.26), DFS (p = 0.38) or OS (p = 0.68) between patients who received CEOP or second/third-generation chemotherapy regimens. Of the patients treated with CEOP, 37.9 per cent, 28.8 per cent, 24.2 per cent and 9.1 per cent were in the age-adjusted International Index L, LI, HI and H risk groups, with CR rates of 82 per cent and 57 per cent in the L/LI and HI/H risk groups (p = 0.03). Moreover, patients in the L, LI and HI/H risk groups had significantly different projected DFS (87 per cent, 62 per cent and 39 per cent, p = 0.02) and OS (85 per cent, 80 per cent and 36 per cent, p = 0.006). In conclusion, CEOP is an effective regimen and the age-adjusted International Index is valid for Chinese patients with aggressive NHL.

Adolescent↗
PubMed1998

Allogeneic bone marrow transplantation for adult acute lymphoblastic leukemia: a single-centre experience.

Between 1990 and 1997, we performed 29 allogeneic BMTs for acute lymphoblastic leukemia (ALL) patients with HLA-identical sibs. Their median age was 31 years (range 15 to 43); there were 15 males and 14 females. The conditioning protocol was Cy-TBI (n = 15), VP16-Cy-TBI(n = 12), CBV (n = 1) and Bu-Cy (n = 1). Cyclosporin and methotrexate were used for GVHD prophylaxis. The median disease-free survival (DFS) was 12 months (range 1 to 92) with an actuarial 4-years DFS of 42.3 per cent. Three patients died of transplant-related complications before 100 days. Relapse occurred in 11 cases at a median time of 5 months (range 3 to 14). All nine patients relapsing within one year died form resistant leukemia. Three patients died of late treatment-related complications. There were 13 survivors (median follow-up 38 months, range 12-98), with 12 in remission. Only four had limited cGVHD, and all had 100 per cent performance scores. One patient also cleared her chronic hepatitis B carrier status due to acquired immunity. The DFS rates amongst CR1 cases and R1/CR2 cases were comparable (p = 0.39). No long-term DFS is obtained from patients with resistant disease (n = 4). The survival results for BMT at CR1 were superior to those using intensive chemotherapy consolidation (p = 0.29), mainly due to poor late results in the chemotherapy arm. For young ALL patients with HLA-matched siblings, the option of BMT should be considered in light of local consolidation survival results.

Adolescent↗
PubMed1998

Use of famciclovir to prevent HBV reactivation in HBsAg-positive recipients after allogeneic bone marrow transplantation.

BACKGROUND/AIMS: Reactivation of chronic hepatitis B viral infection causes significant morbidity and mortality after bone marrow transplantation. Recently, nucleoside analogues, such as famciclovir, were found to have a direct suppressive effect on hepatitis B virus replication in both in vitro and in vivo studies. We have studied the effect of famciclovir on the incidence of hepatitis B virus reactivation and hepatitis after allogeneic bone marrow transplantation. METHODS: Eight hepatitis B surface antigen (HBsAg)-positive patients who received allogeneic bone marrow transplantation were given oral famciclovir 250 mg three times daily, starting at least 1 week prior to bone marrow transplantation and continuing for 24 weeks after transplantation. Clinical and serological outcomes in these patients were compared with 24 HBsAg-positive recipients of allogeneic bone marrow transplantation who did not receive famciclovir (historical controls). RESULTS: After bone marrow transplantation, there were five patients with hepatitis B virus reactivation among those who received famciclovir 250 mg three times daily. Four of these patients responded to increased dosages of 500 mg three times daily and did not develop hepatitis. The remaining patient suffered from hepatitis related to hepatitis B virus reactivation. Compared to historical controls, there were fewer cases of hepatitis due to hepatitis B virus reactivation and veno-occlusive disease. The median follow-up was 701.6 days (range: 50-2346 days) with ten deaths (three due to hepatic failure related to HBV reactivation) in those who did not receive famciclovir and one death (due to hepatic failure related to graft-versus-host disease) in those who received famciclovir. CONCLUSIONS: Use of famciclovir significantly reduced hepatitis due to hepatitis B virus reactivation in HBsAg-positive recipients after allogeneic bone marrow transplantation.

2-Aminopurine↗
PubMed1998

Detoxification of aflatoxin B1 by enzymes isolated from Armillariella tabescens.

Detoxification of aflatoxin B1 (AFB1) by Armillariella tabescens multienzyme, which was isolated from mycelium pellets of A. tabescens, was confirmed by thin-layer chromatography (TLC) and rat assay. The results of toxicology and pathology studies showed that toxicity of AFB1 was minimized after treatment with A. tabescens multienzyme. The result of the Ames test indicated that the mutagenic activity of multienzyme-treated AFB1 was greatly reduced (or inactivated) compared with that of untreated controls. TLC determinations showed that AFB1 at an initial concentration of 16 microM was completely detoxified (100%) by the fungal multienzyme. The infrared spectrum suggests that the multienzyme is responsible for opening the difuran ring of AFB1.

Aflatoxin B1↗
PubMed1998

Recurrent isolated extramedullary relapses as granulocytic sarcomas following allogeneic bone marrow transplantation for acute myeloid leukemia.

Isolated extramedullary relapses as granulocytic sarcomas (GS) following allogeneic bone marrow transplantation (BMT) for acute myeloid leukemia (AML) are rare events. We describe three such patients who presented with a unique pattern of GS relapse post-BMT. The clinical features included repeated relapses in multiple sites, absence of marrow involvement, and prolonged survival. Fluorescence in situ hybridization (FISH) demonstrated persistence of donor hematopoiesis despite disseminated GS. The findings indicated that a graft-versus-leukemia (GVL) effect might operate more strongly in the marrow than in peripheral sites. Finally, our observations suggest that isolated GS relapses after BMT might be compatible with long survivals, and that in patients with marrow hematopoiesis of donor origin, augmentation of the GVL effect might be of use.

Adult↗
PubMed1998

Unique risk factors for bacteraemia in allogeneic bone marrow transplant recipients before and after engraftment.

A study of the risk factors associated with bacteraemia in 191 allogeneic bone marrow transplant (BMT) recipients (1991-1996) was performed. In contrast to risk factors commonly cited for cancer chemotherapy, mucositis, degree of conditioning toxicity of the gut and lungs, duration of neutropenia, and severity of neutropenia and monocytopenia were not associated with bacteraemia in the pre-engraftment period, during which the only significant risk factor was late stage underlying disease (P < 0.05). After engraftment, Hickman catheter infection, and severe acute and chronic graft-versus-host disease (GVHD) were found to be independently associated with bacteraemia by multivariate analysis (P < 0.001, <0.05 and <0.05, respectively). This might be explained by intense antimicrobial prophylaxis, early empirical treatment, and non-routine use of haemopoietic growth factors. No significant difference in mortality was detected between bacteraemic and non-bacteraemic patients in both periods. Allogeneic BMT recipients are therefore a group of patients distinct from other cancer patients receiving chemotherapy at risk of developing bacteraemia. The study findings prompt consideration of a management protocol incorporating early and routine use of haemopoietic growth factors before engraftment in high-risk patients with late stage underlying malignancies, routine antimicrobial prophylaxis for acute GVHD with intense immunosuppression, and intravenous immunoglobulin therapy for chronic GVHD. Further cost-benefit analyses are warranted.

Adolescent↗
PubMed1998

Isolated extramedullary relapse after allogeneic bone marrow transplantation for chronic myeloid leukemia.

Relapse of chronic myeloid leukemia (CML) as extramedullary granulocytic sarcoma (GS) after allogeneic bone marrow transplantation (BMT) is a rare occurrence. We report two patients who developed spinal GS as the first indication of relapse after allogeneic BMT for CML. In both cases, the marrow was in morphologic and karyotypic remission. However, fluorescence in situ hybridization (FISH) successfully demonstrated the presence of a minor Ph-positive clone in the marrow, as well as an occult clone with an additional Ph chromosome detected in one case. The results indicated a stronger graft-versus-leukemia effect in the marrow than in the peripheral tissues.

Adult↗
PubMed1998

Clearance of persistent hepatitis B virus infection in Chinese bone marrow transplant recipients whose donors were anti-hepatitis B core- and anti-hepatitis B surface antibody-positive.

Thirteen hepatitis B surface antigen-positive Chinese patients who received hepatitis B surface antibody-positive marrow (hepatitis B core antibody-positive or -negative: 6 and 7, respectively) via allogeneic bone marrow transplantation (BMT) were studied. After BMT, 4 recipients had serologic clearance of hepatitis B surface antigen from hepatitis B core antibody-positive marrow, but none of the recipients of hepatitis B core antibody-negative marrow had serologic clearance (P=.02). There was no significant difference in the donors' hepatitis B surface antibody titer before BMT for patients with or without serologic clearance of hepatitis B surface antigen (2255.2+/-4244.0 vs. 854.2+/-2306.7 mIU/mL; P=not significant). Adoptive immunity clearance of hepatitis B surface antigen was favored by hepatitis B core antibody positive-donor marrow and was not related to donor pre-BMT hepatitis B surface antibody titer.

Adolescent↗
PubMed1998

[Cloning and orientation of cefoperazone resistance gene on plasmid pFC in E. coli HX88108].

Cefoperazone resistance gene (CPZr) has been cloned from plasmid pFC of E. coli HX88108 using the vector pMB9 (TCr, 5.3 kb). The plasmid pFC DNA was partially digested with Sau3A I, and its 1-2 kb fragments were ligated into BamH I site of vector plasmid pMB9. The recombinant DNA was then transformed into E. coli DH5 prepared using calcium chloride. CPZ resistant bacterial colonies were selected on the agar SOB plates containing CPZ (40 micrograms/ml). The resistance to CPZ could be stably reserved in generation after generation. The recombinant plasmids which encoded CPZ resistance were designated pFL11, pFL25, pFL33, pFL82, pFL86 and pFL102. Rapid small-scale preparation of plasmid and DNA restrication enzyme analysis were used for identification of bacterial colonies. Five plasmids DNA physical maps have been established. Comparison of recombinant plasmids maps with pFC map confirmed that the CPZr gene was oriented between nucleotide no. 3200 bp and no. 4800 + 40 bp of plasmid pFC total sequence. Its molecular weight was about 1.6 kb. There were EcoR I, Sma I and Pvu II sites within CPZr gene.

Cefoperazone↗
PubMed1998

[Analysis of 196 cases of trial of labor with borderline oligohydramnios assessed by ultrasound].

OBJECTIVE: To determine the effect of borderline oligohydramnios on perinatal outcome. METHOD: Patients admitted for delivery had an amniotic fluid index (AFI) assessment. Color Doppler was used to examine the systolic/diastolic ratio of the blood flow velocity in fetal umbilical arteries. Normal amniotic fluid volume was defined as an AFI of 8.1-18 cm (n = 200), and borderline oligohydramnios as 5.1-8.0 cm (n = 196). The two groups were compared on perinatal outcomes as all of the patients had trial of labor. RESULTS: There was no difference in the incidence of fetal distress and neonatal mortality between the two groups. The incidence of emergency section in borderline oligohydramnios group was significantly higher. CONCLUSION: The patients with borderline oligohydramnios may have a trial of labor under proper intensive care.

Female↗
PubMed1998

[Dynamic effect of tifukang on brain proopiomelanocortin gene expression of exercise-induced fatigue rat].

OBJECTIVE: To study the mechanism of exercise-induced fatigue (EIF) and effect of Tifukang (TFK) from the gene transcription level. METHODS: In situ hybridization was adopted, using biotin-labelled proopiomelanocortin (POMC) cRNA probe and integrating with image pattern analysis, to observe the effect of TFK on changes of POMC mRNA expression in different areas of EIF rat's brain. RESULTS: TFK could significantly strengthen POMC mRNA expression in hippocampal CA1 and hypothalamus and inhibit obviously that in frontal cortex of chronic fatigue rats. In rats managed with long term (7 weeks in total) and high intensity exercise with the speed increased from 15 m/min gradually to 35 m/min, 20 to 25 min/d, after the final exercise, the POMC mRNA expression in frontal cortex and hippocampal CA1 decreased (the latter recovered at 30 minutes after ending exercise but the former was not recovered yet 3 hours after the ending of exercise), while that in hypthalamus increased. TFK could remarkably increase POMC gene expression in the above-mentioned three areas after the final exercise especially prominent at the time of 3 hours after the ending of exercise. CONCLUSION: The dynamic changes of POMC gene expression in different areas of EIF rat's brain were not the same, and TFK displayed an important dynamic regulating effect on it.

Animals↗
PubMed1997

Polyvalent binding to carbohydrates immobilized on an insoluble resin.

Numerous studies have established that polyvalency is a critical feature of cell surface carbohydrate recognition. Nevertheless, carbohydrate-protein interactions are typically evaluated by using assays that focus on the behavior of monovalent carbohydrate ligands in solution. It has generally been assumed that the relative affinities of monovalent carbohydrate ligands in solution correlate with their polyvalent avidities. In this paper we show that carbohydrate ligands synthesized directly on TentaGel beads interact with carbohydrate-binding proteins in a polyvalent manner. The carbohydrate-derivatized beads can, therefore, be used as model systems for cell surfaces to evaluate polyvalent carbohydrate-protein interactions. By using a combinatorial approach to synthesize solid-phase libraries of polyvalent carbohydrates, one can rapidly address key issues in the area of cell surface carbohydrate recognition. For example, studies reported herein demonstrate that there is an unanticipated degree of specificity in recognition processes involving polyvalent carbohydrates. However, the correlation between polyvalent avidities and solution affinities is poor. Apparently, the presentation of carbohydrates on the polymer surface has a profound influence on the interaction of the ligand with the protein receptor. These findings have implications for how carbohydrates function as recognition signals in nature, as well as for how polyvalent carbohydrate-protein interactions should be studied.

Carbohydrate Metabolism↗