Biomedical subjects

R Liang

Publications and source records attributed to R Liang.

322 records · Page 18Linked to original sources

PubMedDate not supplied

Follicular non-Hodgkin's lymphoma in Hong Kong Chinese: a retrospective analysis.

Follicular lymphoma is relatively rare in Hong Kong Chinese. Fifty-two patients with follicular lymphoma were reviewed. The histology was nodular lymphocytic poorly differentiated (NLPD) in 75 per cent, nodular mixed (NM) in 21 per cent and nodular histiocytic (NH) in 4 per cent. Our patients appeared to have a higher proportion of NLPD and a lower proportion of NM lymphoma than the western series. Fifty patients were analysed excluding the two patients with NH lymphoma. They had a median age of 50 and a male to female ratio of 0.92. Seventy-two per cent of them presented with asymptomatic lymph node enlargement. Twenty per cent had B symptoms and 32 per cent bulky tumour. Twelve per cent had stage I disease, 2 per cent stage II, 30 per cent stage III and 56 per cent stage IV. A high incidence of bone marrow involvement (48 per cent of all patients) was found. All seven stage I-II patients responded to involved-field radiotherapy alone and none of them has relapsed. The 43 stage III-IV patients were treated with chemotherapy without deferral and a majority of them received CVP (51.1 per cent) or chlorambucil alone (34.9 per cent). The complete response rate of stage III-IV patients was 81 per cent and 26 per cent of the complete responders relapsed. The 5-years disease-free survival (DFS) and overall survival of all patients (stage III and IV) were 50 per cent and 65 per cent respectively. The DFS curve showed a pattern of continuous relapses. Stage III patients appeared to have a better complete response rate, a lower relapse rate and superior disease-free survival than stage IV patients but the differences did not reach statistical significance. However, the overall survival of stage III patients was significantly better than stage IV patients (p less than 0.02). Other factors including sex, age, presence of bulky tumour, B symptoms, histologic subtypes and the chemotherapeutic regimes did not significantly affect their prognosis.

Adolescent↗

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Hodgkin's disease in Hong Kong Chinese.

A lower incidence of Hodgkin's disease in Orientals has been recognized. Although most Hong Kong Chinese came from the Guandong province of China, the incidence of Hodgkin's disease in Hong Kong Chinese is 9.2 per cent which is more comparable to the low figure of 6 per cent in Japan than the 32 per cent incidence in Guangdong. If this discrepancy in the ethnically similar populations is confirmed, other etiological or promoting factors must be considered. Ninety-two Hong Kong Chinese patients (54 males and 38 females) with Hodgkin's disease were reviewed. The median age was 34 years (range 5-79 years). The histology was lymphocyte predominant in nine (10 per cent), nodular sclerosing in 34 (37 per cent), mixed cellularity in 29 (31 per cent), lymphocyte depleted in nine (10 per cent) and unclassified in 11 (12 per cent). Seventeen per cent had stage Ia disease, 2 per cent Ib, 15 per cent IIa, 11 per cent IIb, 11 per cent IIIa, 9 per cent IIIb, 11 per cent IVa and 24 per cent IVb. Twenty-five of them (27 per cent) were staged by laparotomy. Twelve patients (13 per cent) had bulky disease. Identical to the pattern observed in Caucasians, our patients had an apparent biomodal age distribution, a male predominance and similar distribution of histological subtypes according to the Rye classification. The absence of an early peak in young adulthood and the lower incidence of the nodular sclerosing subtype reported in the Japanese was not observed in our patients. A variety of treatments were given to the 92 patients. Most of the patients with stage I-II disease received radiotherapy except for those with B symptoms, bulky disease or lymphocyte depleted histology, who received chemotherapy with or without radiotherapy. All patients with stage III-IV disease received chemotherapy with or without radiotherapy except for two patients with stage IIIa disease who had total nodal irradiation only. The multivariate analysis revealed that Ann Arbor staging was a significant independent factor determining the disease-free survival of patients in complete remission and the overall survival of all patients. Age was the other independent variable significantly determining the overall survival.

Adolescent↗

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Secondary central nervous system involvement by non-Hodgkin's lymphoma: the risk factors.

The risk of secondary central nervous system (CNS) was estimated in 833 cases of non-Hodgkin's lymphoma diagnosed between January 1975 and December 1988. Fifty-one of them had CNS disease (51/833, 6.1 per cent). No case of low grade lymphoma developed CNS disease. However, 6.5 per cent and 16.7 per cent of patients with intermediate and high grade lymphomas, respectively, had secondary CNS involvement. Stage IV disease and the presence of B symptoms were also associated with an increased risk of CNS disease. Significantly higher incidence of CNS disease was seen in patients with lymphoma involving orbit (43 per cent), testis (40 per cent), peripheral blood (33 per cent), bone (29 per cent), nasal/paranasal sinuses region (23 per cent) and bone marrow (20 per cent). CNS prophylaxis is recommended to patients with an increased risk of CNS disease.

Brain Neoplasms↗

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Presence of Epstein-Barr virus DNA in nasal lymphomas of B and 'T' cell type.

We studied 12 tumours from 11 Chinese patients with primary nasal lymphoma for presence of Epstein-Barr Virus (EBV) DNA, using Southern-blot analysis. These results were correlated with immunophenotype and T-cell receptor (TcR) or immunoglobulin gene rearrangement patterns. EBV DNA was detected in all nine tumours with a 'T' phenotype, in both primary and secondary sites. When the structure of the viral genomic termini was studied using the EcoRI-Dhet probe, a single clonal episomal band was demonstrated in five tumour samples, with one other case showing a biclonal pattern. However, none of these cases showed clonal rearrangement of TcR beta chain gene, and TcR gamma rearrangement was found only in one. The lineage of these phenotypic 'T' lymphomas therefore require further studies for confirmation. Two out of three B-lymphomas were also EBV DNA+; clonal EBV DNA was found in one. Their B-lineage was confirmed by detection of clonal immunoglobulin gene rearrangements. The association of EBV with an increasing number of lymphomas of different types highlights the need for continued study into its role in oncogenesis.

Blotting, Southern↗

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Non-Hodgkin's lymphomas involving the female genital tract.

Thirteen female patients with lymphomas involving the genital tract were studied. Their median age was 50 years. There were three cases of stage I disease, one stage II and nine stage IV. The gastrointestinal tract was commonly involved in patients with disease in the ovary. The histology was mostly intermediate or high grade according to the Working Formulation. Immunophenotyping was performed in six patients and they were all B-cell tumours. There appeared to have a strong association between gastrointestinal involvement and ovarian disease. All patients received combination chemotherapy with or without additional radiotherapy and the survival of patients with stage I and II disease appeared to be superior to those with stage IV disease. However, the difference observed did not reach statistical significance because of small patient number. It remains uncertain whether lymphomas of the female genital tract by itself carries a poorer prognosis than the nodal lymphomas of comparable stage and histology.

Adult↗

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Primary and secondary cutaneous lymphomas in Hong Kong Chinese.

Sixty-eight Hong Kong Chinese patients with cutaneous lymphomas were studied. There were 38 males and 30 females and their median age was 52 years. According to a staging system as proposed by the Mycosis Fungoides Cooperative Group, 48 (71 per cent) of the patients had disseminated stage IV disease. There were nine (13 per cent) cases of mycosis fungoides. The remaining cases were mostly intermediate or high grade non-Hodgkin's lymphomas according to the Working Formulation. Immunophenotyping was performed in 23 cases and in 17 cases (74 per cent), T-cell tumours were identified. Many of these T-cell lymphomas were unclassifiable according to the Working Formulation and were either pleomorphic or immunoblastic-lymphadenopathy-like T-cell lymphoma according to a modified system of the Japanese Lymphoma Study Group. A variety of therapies were given to these patients and those with stage IV disease had a significantly poorer survival. On the other hand, the histology, and immunophenotype did not appear to be useful in predicting prognosis.

Adolescent↗

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The prognostic factors for peripheral T-cell lymphomas.

The peripheral T-cell lymphomas of 50 patients were classified by histological type and tumour cell size, the latter as described by the Nebraska Group. There was no difference in the pattern of their clinical features among the various histological subtypes and their clinical outcome was similar. Cell size and other factors including sex, age, presence of B symptoms, sites of primary disease, histological subtypes according to the Japanese classification, lactate dehydrogenase level and presence of bulky disease did not appear to correlate with clinical outcome. However, patients with stage IV disease had significantly lower CR rate (9/29 versus 16/21, p = 0.01) and poorer survival at 3 years (p = 0.05) than those with stage I, II and III disease. Patients receiving COPP, the less intensive chemotherapy regimen, appeared to have poorer clinical outcome but the difference observed was not statistically significant because of the number of patients in each subgroup.

Age Factors↗

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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↗

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Intensive chemotherapy for peripheral T-cell lymphomas.

Forty-two patients with previously untreated peripheral T-cell lymphomas (PTCL) were treated with an intensive chemotherapy protocol. Either the BACOP or the m-BACOD regimen was used for induction. Patients achieving complete clinical remission after three courses were given intensive consolidation and maintenance chemotherapy similar to the L10/L17M protocol designed by the Memorial Sloan-Kettering Group for acute lymphoblastic leukemia and lymphoblastic lymphoma. There were 27 (64 per cent) males and 15 (36 per cent) females. The median age was 54 years (mean 53, range 15 to 68). Seven of them (17 per cent) had stage I disease, four (10 per cent) stage II, seven (17 per cent) stage III and 24 (57 per cent) stage IV. Eighteen patients (43 per cent) had B symptoms and four (10 per cent) had bulky disease. According to the Working Formulation, the histology was diffuse mixed in 16 patients (38 per cent), diffuse large cell in 18 (43 per cent), diffuse immunoblastic in four (10 per cent) and unclassifiable in four (10 per cent). According to a modified Japanese Lymphoma Study Group's classification, the histology in 24 patients (57 per cent) was the pleomorphic type, in 13 (31 per cent) immunoblastic-lymphadenopathy-like (IBL-like), and in five (12 per cent) unclassifiable. The overall complete remission rate was 67 per cent. Twenty-five per cent of the complete responders relapsed and the DFS of the CR patients was 62 per cent at three years. The overall survival of all patients at three years was 52 per cent. Patients with stage I, II and III disease had significantly better CR rate (100 per cent versus 42 per cent, p = 0.001) and overall survival (82 per cent versus 35 per cent at three years, p = 0.01) than those with stage IV disease but the relapse rate and DFS of CR patients were similar. This study shows that the prognosis of patients with PTCL can be improved by intensive therapy.

Adolescent↗

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COPP chemotherapy for elderly patients with intermediate and high grade non-Hodgkin's lymphoma.

One hundred and forty-one consecutive patients above and 231 below the age of 60 years with previously untreated intermediate or high grade non-Hodgkin's lymphoma were included in this study. Patients above the age of 60 years were treated with the COPP chemotherapy regimen. The younger patients, at or below the age of 60, received a doxorubicin-containing regimen (119 had CHOP, 65 had BACOP and 47 had m-BACOD). For stage I patients, the clinical results were similar but for stage II, III or IV disease, those receiving COPP had significantly worse CR rate and survival than those who had a doxorubicin-containing regimen. Multivariate analysis on patients receiving the COPP chemotherapy revealed that the independent prognostic variables significantly determining CR rate and survival included clinical stage (p = 0.04) and serum lactate dehydrogenase level (p = 0.001). Myelosuppression was the major toxicity following COPP chemotherapy in this group of patients. There were 10 (7 per cent) treatment-related deaths. Compared to the reported results using doxorubicin-containing regimens to treat elderly patients with aggressive NHL in the literature, the more aggressive treatment does not appear to improve significantly the clinical outcome of this group of patients and seems to produce treatment results very much similar to COPP. However, accurate comparison is difficult because of the variation in the patient characteristics. Further prospective controlled randomized trials will be necessary to determine the optimal therapy for these patients.

Adolescent↗

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Prognostic factors for primary gastrointestinal lymphoma.

The gastrointestinal tract is a common primary extranodal site for non-Hodgkin's lymphoma. There is however no uniform consensus on its pathological classification, clinical staging system and management. This paper reports the experience in the management of 425 Chinese patients with primary gastrointestinal lymphoma in Hong Kong from January 1975 to June 1993. There were 230 (54 per cent) males and 195 (46 per cent) females. Their median age was 53 years. The primary sites were: the esophagus in three (1 per cent), stomach in 238 (56 per cent), small intestine in 131 (31 per cent) and large intestine in 53 (12 per cent). According to the Working Formulation, there were 20 (4.7 per cent) small lymphocytic, 10 (2.4 per cent) follicular small cleaved cell, 15 (3.5 per cent) follicular mixed, five (1.2 per cent) follicular large cell, 40 (9.4 per cent) diffuse small cleaved cell, 50 (12 per cent) diffuse mixed, 181 (43 per cent) diffuse large cell, 30 (7.1 per cent) immunoblastic, five (1.2 per cent) lymphoblastic, 10 (2.4 per cent) diffuse small non-cleaved cell and 50 (14 per cent) unclassifiable lymphoma. Immunophenotyping was performed in 199 (47 per cent) patients: 90 per cent B-cell, 7 per cent T-cell and 3 per cent uncertain. According to a Manchester system, 81 (19 per cent) patients had stage I disease, 44 (10 per cent) stage II, 85 (20 per cent) stage III and 215 (51 per cent) stage IV. B symptoms were present in 275 (65 per cent) patients and bulky disease in 104 (25 per cent). Surgery followed by chemotherapy was the mainstay of treatment. Of the 408 patients treated, 63 per cent had a complete remission with relapse rate of 42 per cent. For those with complete remission, 47 per cent were free from disease at 5 years. The overall median survival of all patients was 45 per cent at 5 years. Multivariate analysis revealed that significant independent prognostic factors predicting better survival were young age of < 60 years, low grade histology, stage I and II disease and absence of bulky tumour. For gastric lymphoma, aggressive surgery did not significantly improve their outcome. Chemotherapy appears to play an important role in the management of gastrointestinal lymphoma. Better classification of the primary gastrointestinal lymphoma and more refined stratification of the patients according to the prognostic variables may allow individualization of treatment. Prospective randomized studies are essential to define the relative roles of surgery, chemotherapy and radiotherapy.

Adult↗

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Hepatitis B virus (HBV) reactivation after cytotoxic or immunosuppressive therapy--pathogenesis and management.

In an endemic area for chronic hepatitis B infection, reactivation of this virus is a serious cause of morbidity and mortality in patients undergoing cytotoxic or immunosuppressive therapy. Careful prospective serological testing has shown that hepatitis B virus reactivation is a two-staged process. The initial stage occurs during intense cytotoxic or immunosuppressive therapy and is characterised by enhanced viral replication, as reflected by increases in the serum levels of hepatitis B virus DNA, hepatitis B e antigen, hepatitis B virus DNA polymerase and infection of naïve hepatocytes with hepatitis B virus. The second stage is related to restoration of immune function following withdrawal of cytotoxic or immunosuppressive therapy, which causes rapid immune-mediated destruction of infected hepatocytes. Clinically, this can lead to hepatitis, hepatic failure and even death. The occurrence and severity of hepatitis B virus reactivation after various cytotoxic or immunosuppressive therapy is unpredictable and treatment has been disappointing, largely due to the late administration of therapy. Recently, pre-emptive treatment of chronic hepatitis B patients undergoing cytotoxic or immunosuppressive therapy, with potent nucleoside analogues has shown some promising results. Further controlled studies are needed to define the incidence and risk factors of hepatitis B reactivation so that pre-emptive treatment with nucleoside analogues could be administered to those patients at high risk of disease.

Antineoplastic Agents↗

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High efficient encapsulation of plasmid DNA in PLGA microparticles by organic phase self-emulsification.

To overcome the drawbacks of encapsulating plasmid DNA (pDNA) in poly (D,L-lactic-co-glycolic acid) (PLGA) by water-in-oil-in-water double-emulsion solvent-evaporation method, we have developed a novel procedure for encapsulating pDNA in PLGA microparticles called DNA organic phase self-emulsification (DOPSM). This method was based on both the extraction plasmid DNA from aqueous phase into organic phase and the spontaneous emulsification DNA in organic phase by solvent diffusion method. The efficiency of extraction plasmid DNA into organic phase is 99% and the concentration of pDNA in organic phase is up to 2.4 mg/ml. The efficiency of microencapsulation of plasmid DNA in PLGA is up to 76% and can be enhanced by lowering the pH of aqueous solution of emulsion. The microparticles size of PLGA of pDNA is in a narrow range of 1-2 microm. This procedure does not involve the high mechanical energy to emulsify which may damage the integrity of pDNA. This method can be applied to encapsulate the pDNA into microparticles of other biocompatible polymers with high efficiency.

Coated Materials, Biocompatible↗

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A limit on spin-charge separation in high-Tc superconductors from the absence of a vortex-memory effect.

There is a long-standing debate about whether spin-charge separation is the root cause of the peculiar normal-state properties and high superconducting transition temperatures of the high-Tc materials. In the proposed state of matter, the elementary excitations are not electron-like, as in conventional metals, but rather the electron 'fractionalizes' to give excitations that are chargeless spin-1/2 fermions (spinons) and charge +e bosons (chargons). Although spin-charge separation has been well established in one dimension, the theoretical situation for two dimensions is controversial and experimental evidence for it in the high-Tc materials is indirect. A model with sharp experimental tests for a particular type of separation in two dimensions has recently been proposed. Here we report the results of those experimental tests, placing a conservative upper limit of 190 K on the energy of the proposed topological defects known as visons. There is still debate about the extent to which this experiment can settle the issue of spin-charge separation in the high-Tc copper oxides, because some forms of the separation are able to avoid the need for visons. But at least one class of theories that all predict a vortex-memory effect now are unlikely models for the copper oxides.

Journal Article↗

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A prospective study of symptomatic bacteremia following platelet transfusion and of its management.

BACKGROUND: The danger of bacteremia due to contaminated platelets is not well known. There are also no established guidelines for the management of febrile reactions after platelet transfusion. STUDY DESIGN AND METHODS: To determine the risk of symptomatic bacteremia after platelet transfusion, 3584 platelet transfusions given to 161 patients after bone marrow transplantation were prospectively studied. Platelet bags were routinely refrigerated for 24 hours after transfusion. Septic work-up was initiated for a temperature rise of more than 2 degrees C above the pretransfusion value within 24 hours of platelet transfusion or a temperature rise of more than 1 degree C that was associated with chills and rigor. Diagnosis of bacteremia after platelet transfusion was made only when the pairs of isolates from the blood and the platelet bags were identical with respect to their biochemical profile, antibiotic sensitivity, serotyping, or ribotyping. RESULTS: Thirty-seven febrile reactions, as defined above, occurred. Bacteremia subsequent to platelet transfusion was diagnosed in 10 cases. There was a 27-percent chance (95% CI, 15-43%) that these febrile reactions represented bacteremia that resulted from platelet transfusion. For a subgroup of 19 patients with a temperature rise of more than 2 degrees C, the risk of bacteremia was 42 percent (95% CI, 23-64%). Septic shock occurred in 4 of the 10 bacteremic patients. A rapid diagnosis was possible because the involved bacteria were demonstrated by direct Gram stain of the samples taken from the platelet bags of all 10 patients. CONCLUSION: Significant febrile reactions after platelet transfusion are highly likely to be indicative of bacteremia. Routine retention of platelet bags for subsequent microbiologic study was useful in the investigation of these febrile reactions. Empiric antibiotic therapy is indicated.

Bacteremia↗

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Evaluation of ibuprofen for pressure ulcer prevention: application of a rat pressure ulcer model.

This blinded study describes the effect of ibuprofen (IBU) on experimental pressure ulcers (PU) induced in the fuzzy rat model. Ibuprofen's fibrinolytic activity has been found effective in preserving dermal vasculature in rats following burn injury. Experimental pressure ulcers were generated on the hips of fuzzy rats with the aid of computer control, using five daily, 6-hour pressure sessions. In the first study, 17 rats received intraperitoneal (I.P.) injection of IBU or saline control after each pressure session. In the second study, 44 rats received IBU or control, before, during, and after application of pressure by I.P. or intramuscular (I.M.) injections. Quantitation of histology is based on five prominent lesions, including: ulceration, infarction, panniculus carnosus necrosis, fat atrophy, and deep muscle necrosis. The following hypothesis was tested: Reperfusion injury and vascular occlusion in pressure ulcers may be similar to that which occurs in burns and, therefore, is responsive to IBU intervention. The results indicate that IBU does not have significant effects on the development of pressure ulcers. The mechanisms of IBU action in other organ and tissue systems are discussed in relation to the effect of IBU on the pressure ulcer model.

Animals↗