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Biomedical subjects

R Liang

Publications and source records attributed to R Liang.

At least 181 records · Page 10Linked to original sources

Can preterm twins breast feed successfully?

AIM: To compare the success of singleton and twin preterm infants in establishing and maintaining breast feeding, and to evaluate the effectiveness of current programmes to promote breast feeding. METHODS: All infants less than 37 weeks gestation discharged in one month from the special care baby unit at National Womens Hospital were studied. Data on the infants and their in hospital course was recorded from the neonatal records. The mothers were contacted by telephone 3 to 4 months after discharge, to elicit the subsequent breast feeding rates. RESULTS: Thirty of 33 preterm infants (29 to 36 weeks gestation) were breast fed at discharge from hospital: 93% of singletons, and 89% of twins. The twins were older and heavier at discharge (p < 0.004) due to their longer hospital stays (28.4 vs 16.3 days, p < 0.05). All but 2 infants progressed to exclusive breast feeding. There was a similar rate of decline in the rates of breast feeding in singletons and twins to 68% at 8-12 weeks and 49% at 12-16 weeks after birth. CONCLUSIONS: Preterm twins can breast feed as successfully as preterm singleton infants; as with sufficient assistance and encouragement, their rates of breast feeding were comparable to those of term infants. Although the resources of this hospital do not allow preterm infants to become fully breast fed before discharge, the current programme at National Womens Hospital is effective in establishing successful breast feeding in these high risk infants.

Breast Feeding↗

Primary cardiac lymphoma.

Primary cardiac lymphoma is a rare entity. We report on the clinicopathological features of 2 patients with primary cardiac lymphomas: one involving the right atrium resulting in intractable right heart failure, and the other involving the pericardium with massive pericardial effusion. In the first patient, sternotomy and surgical biopsy of the tumor were performed to arrive at the diagnosis. In the second patient, CT thorax and transesophageal echocardiography helped to diagnose the pericardial tumor, and cytological examination of the pericardial fluid established the pathological diagnosis of lymphoma. Combination chemotherapy (COPP) was started in both patients. The first patient died on the first day of chemotherapy due to intractable heart failure, while the second attained a partial response to chemotherapy but died of progressive disease 8 weeks later. This is followed by a literature review of 21 patients with primary cardiac lymphoma. In conclusion, the prognosis of primary cardiac tumor remains poor.

Aged↗

Polycythemia vera in Chinese patients: thirty-six years of experience.

Forty-one patients with polycythemia vera (PV) according to the PVSG criteria were analysed retrospectively from January 1960 to March 1996. There were 23 male and 18 female patients with a median follow-up of 66.5 months (3-431 months). Median age was 62 (range: 37-85). The median hemoglobin level at diagnosis was 18.8 g/dl. Four patients were treated by venesection alone, 20 patients received hydroxyurea and intermittent venesection, 3 were treated with radioactive phosphorus alone, and 14 had both hydroxyurea and radioactive phosphorus. During the course of illness, 14 patients (34%) developed a total of 19 thrombotic events. Of the thrombotic events, 16 were arterial and 3 were venous. Two patients had both arterial and venous thrombosis sequentially. The probability of thrombosis-free survival after treatment was 83% at 10 years and 73% at 20 years. One patient developed post-polycythemic myeloid metaplasia 24 months after diagnosis. Of 17 patients exposed to radioactive phosphorus, only 1 developed secondary acute myeloid leukemia (AML) 9 years afterwards. Of the 20 patients treated with hydroxyurea for a median duration of 63.5 months (2-130 months), there is no case of secondary malignancy. Overall survival was 83% at 10 years and 62% at 20 years. In conclusion, PV in Chinese is a relatively benign disease with a low risk of thrombosis as compared to Caucasian patients. Hydroxyurea has a very low risk of secondary leukemia and is a safe drug to use in Chinese patients with PV.

Adult↗

Improved treatment outcome in adult acute lymphoblastic leukemia using the intensive German protocol, a preliminary report.

Thirty-nine consecutive patients with acute lymphoblastic leukemia were treated with an intensive chemotherapy protocol. There were 23 males and 16 females with a median age of 37 years (range: 15-65). Eighteen patients had common ALL, seven had pre-B ALL, three early-precursor B ALL, seven T-ALL and four had aberrant expression of myeloid antigens (c-ALL in three and pre-B ALL in one). The median initial leukocyte count was 11.8 x 10(9)/l (range: 0.65-295). Cytogenetic result of the marrow was available in 16 of 39 patients (41 per cent) and showed Philadelphia positivity in six, a normal result in six and one each of t(4,11), t(1,19), hyperdiploidy and del 12p. Hepatosplenomegaly was present in about 20 per cent of the patients. L-Asparaginase-related hepatic toxicity was the commonest toxicity (48.7 per cent) during phase I of induction. Prolonged pancytopenia and hypoplastic death were common during phase II. With the use of growth factors during the neutropenic period of phase II induction, the rate of hypoplastic death was reduced from 40 per cent to 3 per cent. Common causes of treatment failure included early hypoplastic death (27.8 per cent) and leukemia relapses (50 per cent) while primary refractory leukemia, hepatic failure and perforated peptic ulcer contributed to 11.1, 5.5 and 5.5 per cent of the other deaths. A high complete remission (CR) rate (87.4 per cent) was achieved after phase I induction. The median event-free survival (EFS) was 8 months and the 3-year event-free survival was 43 per cent. This result compared favourably to the other regimens previously employed in our institution. In conclusion, satisfactory survival can be achieved with this intensive regimen. Good supportive care was however, essential to minimize toxicities.

Adolescent↗

Lymphoma of the breast in Hong Kong Chinese.

Fourteen cases of non-Hodgkin's lymphoma presenting as breast mass from 1974 to 1996 were reviewed. The median age of presentation was 51 years. Three patients had bilateral disease and five had disseminated disease. A predominance of B cell disease of diffuse large cell histology was noted. Painless lumps were the most common presenting features and most patients were treated with excisional biopsy followed by combination chemotherapy. Radiotherapy was added to local bulky disease. Six patients, however, underwent mastectomy. The overall CR rate was 74 per cent, lasting a median of 32 months. At a median follow-up of 60 months five patients were still alive, one with relapsed disease. Salvage treatments for relapsed patients were uniformly poor. Compared to reported western series, our patients had more high grade disease, more T cell disease and more CNS relapses. Improvements in treatment may involve the use of fine needle aspiration of breast lesion prior to surgery, primary CNS prophylaxis in high grade disseminated disease and high dose chemotherapy with marrow/stem cell rescue in relapsed cases.

Adult↗

High incidence of BCL-6 gene rearrangement in diffuse large B-cell lymphoma of primary gastric origin.

The incidence of BCL-6 gene rearrangement was studied in 39 Hong Kong Chinese patients with diffuse large B-cell lymphoma. The primary site of involvement was nodal in 18 cases and gastric in 21 cases. Clonal BCL-6 gene rearrangement was found in 17% of the patients with primary nodal and 48% with primary gastric lymphoma (p = 0.05). The clinical characteristics and treatment outcome of the 21 patients with primary gastric lymphoma were analyzed according to the BCL-6 status. Significantly more patients in the germline BCL-6 gene group had advanced stage (II, III and IV) of disease. Complete remission rate following primary therapy appeared to be higher for the positive rearrangement group (70% versus 36%), but it was not statistically significant. Those with a rearranged BCL-6 gene also appeared to have better survival at 5 years (58% versus 36%) but the difference was also not statistically significant. On the other hand, patients being classified as low risk according to the International Prognostic Index had significantly better survival at 5 years (89% versus 9%, p = 0.0001). We concluded that BCL-6 gene rearrangement was more commonly found in diffuse large B-cell lymphoma of primary gastric origin than its nodal counterpart and it may be playing a more important role in the pathogenesis of gastric large B-cell lymphoma. There was a trend that the BCL-6 gene rearrangement was associated with a more favorable outcome in patients with gastric large B-cell lymphoma but the difference was not statistically significant.

Adult↗

Autologous bone marrow transplantation for primary nasal T/NK cell lymphoma.

Primary nasal T or NK cell lymphoma is rarely seen in the Western population but is more common in the Orientals. Although it often presents with localized disease, the prognosis is generally poor. Long-term remission is seen in only 50% of patients with stage I disease despite aggressive treatment with chemotherapy and radiotherapy, and is invariably fatal if disseminated. Conventional chemotherapy for relapsed disease is usually not successful. Since 1992, three patients with relapsed primary nasal T/NK cell lymphoma have received high-dose chemotherapy with autologous bone marrow rescue at Queen Mary Hospital, Hong Kong. High-dose cyclophosphamide, BCNU and etoposide were used for conditioning. Two of them had a favourable response and remained in complete remission at 12 and 44 months post-transplant. The third patient unfortunately had a systemic relapse 6 months after the transplant. It appears from this experience that, like other aggressive non-Hodgkin's lymphomas, high-dose chemotherapy and autologous bone marrow rescue is an effective treatment for relapsed primary nasal lymphoma following failure of conventional chemotherapy and radiotherapy.

Adult↗

Hepatic events after bone marrow transplantation in patients with hepatitis B infection: a case controlled study.

Hepatitis B reactivation following chemotherapy withdrawal may result in hepatitis, hepatic failure and death. We studied the clinical outcome and the causes of hepatic events of hepatitis B surface antigen positive recipients undergoing bone marrow transplantation. Twenty-four hepatitis B surface antigen patients were matched with 24 hepatitis B surface antigen negative patients for age, sex, CMV positive serology, underlying hematological disease and type of bone marrow transplantation. Post-BMT, there were 18 patients in the hepatitis B surface antigen positive group and four patients in the hepatitis B surface antigen negative group who suffered from hepatitis (P < 0.05). Thirteen of the 18 hepatitis were related to HBV reactivation in the hepatitis B surface antigen positive group and none of the four hepatitis in the hepatitis B surface antigen negative group (P = 0.01). The hepatitis B surface antigen positive group also had an increased incidence of acute graft-versus-host disease of liver (6 vs 1, P = 0.03). However, there was no significant increase in the incidence of veno-occlusive disease (10 vs 7, P = 0.40) and persistent hepatitis (3 vs 0, P = 0.07) in the hepatitis B surface antigen positive group. Using the log-rank test, there was no significant difference in survival between the hepatitis B surface antigen positive and negative recipients.

Adult↗

CD56+ NK lymphomas: clinicopathological features and prognosis.

The surface molecule CD56 marks a category of malignant lymphoma of putative natural killer (NK) cell origin. We conducted a retrospective analysis of 24 cases of CD56+ NK lymphoma/leukaemia to define the clinicopathologic and prognostic features of this specific group of lymphomas. 56 cases of nasal lymphomas and 204 cases with an initial diagnosis of peripheral T-cell lymphoma were retrospectively analysed. To specifically examine lymphomas of putative NK origin, only those that were negative for surface expression of CD3 but positive for CD56 were analysed. 24 cases were identified. The initial predominant sites of involvement were nasal (n = 18), palate (n = 1), nodal (n = 1) and multi-organ (n = 4). Clinically, in patients with disease localized to one anatomical site (n = 20), most had symptoms confined to the nose, with a high percentage in early stage (I: 91%; IV: 9%). The marrow was not involved in any of these cases. However, patients with multi-organ involvement at presentation (n = 4) behaved differently. All presented acutely with pancytopenia, hepatosplenomegaly, and marrow infiltration with haemophagocytosis. A leukaemic phase was observed in one case. Anthracycline containing combination chemotherapy resulted in complete remission in 75% of patients with localized disease, but only in 25% with multi-organ involvement. The median survival of patients with localized disease was 12 months, compared with 2 months in the multi-organ group (P = 0.06); the disease-free survival was significantly better in the former (P < 0.01). The overall median survival of all patients was still poor at 11 months. We conclude that CD56+ NK lymphomas could be divided into two main patterns of disease presentations: localized (predominantly nasal), and multi-organ involvement. Each has different clinicopathologic and prognostic features. Conventional chemotherapy appeared ineffective for the majority of patients, and innovative treatment modalities are needed to improve outcome.

Adolescent↗

Bcl-6 gene hypermutations in diffuse large B-cell lymphoma of primary gastric origin.

The presence of the bcl-6 gene hypermutation was studied in 40 Hong Kong Chinese patients with diffuse large B-cell lymphoma. The primary sites of involvement were nodal in 18 cases and gastric in 22. Hypermutations at the E1.11 segment of bcl-6 gene were detectable in 16/22 (73%) primary gastric and 4/18 (22%) primary nodal lymphoma (P<0.01). Three of the 22 cases of primary gastric but none of the nodal lymphoma had mutations at E1.12. The proportion of hypermutated cases in the group with bcl-6 gene rearrangement was similar to that of the germ-line group (70% v 75%). High frequency of bcl-6 gene hypermutations was found in diffuse large B-cell lymphoma of the stomach and they were independent of rearrangement of the gene as detected by Southern analysis. Unlike gene rearrangement, hypermutations of the bcl-6 gene did not appear to carry any prognostic significance clinically.

Adult↗

Persistence of hepatic hepatitis B virus after serological clearance of HBsAg with autologous peripheral stem cell transplantation.

Delayed clearance of hepatitis B surface antigen was previously reported in a 38 year old woman after high dose chemotherapy with autologous peripheral blood stem cell rescue. Sixteen months later, this patient remained hepatitis B surface antigen negative, hepatitis B surface antibody positive, and serum hepatitis B DNA negative by polymerase chain reaction. Serial liver biopsies (one at hepatitis B e antigen positive stage, one at hepatitis B e antibody positive stage, and one at hepatitis B surface antigen negative and hepatitis B surface antibody positive stage) showed a gradual resolution of the inflammatory activity with loss of hepatitis B e antigen and then hepatitis B surface antigen in the serum. However, the degree of fibrosis, though mild, remained the same. With the serological clearance of hepatitis B surface antigen, a small amount of hepatitis B virus DNA was still detectable in the nuclei of liver cells.

Adult↗

Molecular detection of minimal residual disease for patients with leukaemia and lymphoma.

Although a complete clinical remission can often be achieved with chemotherapy for patients with leukaemia and lymphoma, relapses still occur. Residual tumour cells probably have survived therapy and account for subsequent disease relapse. The sensitivity of conventioned ways of detecting residual tumour cells, such as morphological studies, immunophenotyping, and cytogenetics, is only about 1% to 5% and may be inadequate. Polymerase chain reaction technology has provided a simple and highly sensitive means for the detection of minimal residual disease. The technology has been successfully applied to study biopsy samples obtained from patients with leukaemia and lymphpma. Its clinical usefulness, however, requires further evaluation by prospective clinical studies.

Journal Article↗

Detection of T-cell receptor delta gene rearrangement by clonal specific polymerase chain reaction.

A sensitive and specific technique to detect minimal residual disease for T-cell malignancies was explored. Southern analysis and polymerase chain reaction (PCR) were used to detect the rearranged V-D-J segment of T-cell receptor delta (TCR delta) gene from malignant cell specimens of patients with leukemia and lymphoma of T-cell lineage. The PCR product was sequenced and from the DNA sequences of the V-D-J region, a 3' antisense primer was designed and synthesized for clonal specific PCR (CS-PCR). Seven of the 22 T-ALL (32%) and 5 of 18 (28%) T-cell lymphoma showed clonal rearrangement by Southern analysis. Six of the 7 (86%) T-ALL and 4 of the 5 (80%) T-cell lymphoma which were Southern positive were also positive by TCR delta PCR. The PCR products of four cases of T-ALL showing clonal pattern by TCR delta PCR amplification were successfully sequenced and CS-PCR amplification performed. CS-PCR detected with confidence specific clonal rearrangement in a mixture containing 0.003% of malignant cells. Marrow specimens obtained at diagnosis and subsequent follow-ups from the 4 T-ALL patients were studied by Southern analysis, TCR delta PCR and CS-PCR. The first patient was in continuous morphological complete remission for more than 3 years and had persistently negative Southern, TCR delta PCR and CS-PCR results on follow-up. Initial follow-up marrow samples from the second patient had persistently positive CS-PCR results while they were still morphologically and TCR delta PCR negative and the patient had a frank leukemic relapse at 18 months. The other two patients had persistent disease by conventional morphological examination, Southern analysis, TCR delta PCR and CS-PCR studies were all positive as expected. CS-PCR is a highly specific and sensitive technique in detecting minimal residual disease for T-cell malignancies. Its potential applications warrant further clinical evaluation and correlation.

Base Sequence↗

Parallel synthesis and screening of a solid phase carbohydrate library.

A solid phase carbohydrate library was synthesized and screened against Bauhinia purpurea lectin. The library, which contains approximately 1300 di- and trisaccharides, was synthesized with chemical encoding on TentaGel resin so that each bead contained a single carbohydrate. Two ligands that bind more tightly to the lectin than Gal-beta-1,3-GalNAc (the known ligand) have been identified. The strategy outlined can be used to identify carbohydrate-based ligands for any receptor; however, because the derivatized beads mimic the polyvalent presentation of cell surface carbohydrates, the screen may prove especially valuable for discovering new compounds that bind to proteins participating in cell adhesion.

Acylation↗