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Biomedical subjects

R Liang

Publications and source records attributed to R Liang.

At least 91 records · Page 5Linked to original sources
PubMed2001

Giant enhancement of the thermal Hall conductivity kappa(xy) in the superconductor YBa(2)Cu(3)O(7).

In high-purity YBa(2)Cu(3)O(7), the (weak-field) thermal Hall conductivity kappa(xy) is observed to increase a thousand-fold between 90 and 30 K. The inferred quasiparticle lifetime tau increases a hundred-fold starting below 90 K, in disagreement with a recent photoemission experiment. We show that kappa(xy) exhibits a specific scaling behavior below approximately 30 K. This scaling may bear on the issue of whether Landau quantization of the quasiparticle states occurs.

Journal Article↗
PubMed2001

Arsenic trioxide- and idarubicin-induced remissions in relapsed acute promyelocytic leukaemia: clinicopathological and molecular features of a pilot study.

Arsenic trioxide (As2O3) effectively induces remissions in relapsed acute promyelocytic leukaemia (APL), but the safety of its long-term administration is unknown. The anthracycline idarubicin is highly active alone or in combination chemotherapy for the treatment of APL. To minimize arsenic exposure and based on the high sensitivity of APL cells to anthracyclines, we conducted a prospective study to evaluate induction with As2O3 followed by consolidation with idarubicin in the treatment of APL in relapse. Eight patients were treated with As2O3 at a daily dose of 10 mg until remission, followed by three monthly courses of idarubicin, at 6 mg/m(2)/day for 5 days in the first course and 6 mg/m(2)/day for 2 days in the subsequent two courses. All patients achieved morphological but not molecular remission after As2O3 treatment. During As2O3 therapy, an increase in white cell count peaking at a median of 17 days occurred in all the cases. Serial flow cytometric analysis of apoptosis, with mitochondrial APO2.7 antigen expression and the sub-G1 cell fraction on DNA histogram as markers, showed induction of apoptosis of APL cells in vivo. With both qualitative and real-time quantitative polymerase chain reaction, all patients were shown to attain molecular remission after subsequent idarubicin treatment. With a median follow up of 13 months, seven of eight patients have remained in complete clinical remission, with six patients in molecular remission as well. One patient who was in third remission became PCR-positive after being transiently negative. One patient died from an intracranial extramedullary relapse after achieving marrow molecular remission. We conclude that As2O3 induction followed by idarubicin consolidation is an effective therapy for APL in relapse. This regimen avoids the possible long-term toxicities of As2O3 and mutagenicity of combination chemotherapy, a strategy that might be suitable for this potentially curable leukaemia.

Adult↗
PubMed2001

Clinicopathologic and prognostic features of chronic idiopathic thrombocytopenic purpura in adult Chinese patients: an analysis of 220 cases.

To determine the clinicopathologic and prognostic features of chronic idiopathic thrombocytopenic purpura (ITP) in adult Chinese patients, we conducted a retrospective analysis of 220 patients seen at a single center over a 40-year period. The female-to-male ratio was 4:1, with a mean age of 42.1 +/- 1.3 years, a mean platelet count of 33.7 +/- 2.3x10(9)/l, and a mean follow-up of 116 +/- 7 months. Initial steroid treatment was required in 142 patients, 67 of whom (47.2%) achieved complete remission (CR). At 470 months, 46% patients remained in CR. Splenectomy was performed in 37 patients: in 23 patients due to primary steroid refractoriness and in 7 patients due to disease relapse following initial CR with steroids. In seven patients, data on response to steroids prior to splenectomy were not available. Splenectomy for steroid nonresponders resulted in an inferior CR rate (13 of 23, 56%) as compared with that for relapses after steroid treatment (7 of 7, 100%) (P<0.05). Compared with patients with negative antinuclear antibody (ANA), those who were ANA positive had similar responses to steroids, but significantly shorter remission after splenectomy (P<0.01). In conclusion, Chinese patients with ITP could maintain long-term remission after steroid therapy and splenectomy. In addition, primary steroid refractoriness and positive ANA were bad prognostic factors of the subsequent response to splenectomy.

Adolescent↗
PubMed2001

Respiratory ciliary function in bone marrow recipients.

Bone marrow transplantation (BMT) recipients, particularly those with chronic graft-versus-host disease (GVHD), suffer from respiratory tract problems, including bronchiolitis obliterans (BO) and recurrent lower respiratory tract infections. Minute cilia beat continuously on the surface of respiratory mucosa, and this beating maintains the sterility of the lower respiratory tract. Dysfunction of respiratory cilia could lead to development of recurrent respiratory tract infections, which are also features of BMT recipients, although ciliary function has not been systematically studied among these subjects. We have, therefore, investigated the ciliary beat frequency (CBF) of 36 Chinese patients who had undergone allogeneic BMT. The CBF was significantly lower in the BMT group compared to controls (P < 0.001). The reduction in CBF was more severe in patients with cGVHD and BO compared with their counterparts (P = 0.048 and P = 0.077, respectively). There was a correlation between CBF with forced expiratory flow rate FEF (P = 0.024) and forced expiratory volume FEV (P = 0.044). We conclude that abnormal ciliary clearance is a common feature after allogeneic BMT, particularly among patients with BO and cGVHD. Further studies are indicated to evaluate this important phenomenon, which could be an important cause of the susceptibility for BMT recipients to respiratory infections.

Adolescent↗
PubMed2001

Late onset post-transplantation lymphoproliferative disease of recipient origin following cytogenetic relapse and occult autologous haematopoietic regeneration after allogeneic bone marrow transplantation for acute myeloid leukaemia.

A post-transplantation lymphoproliferative disease (PTLD) of recipient origin was identified in one of 376 consecutive cases of allogeneic bone marrow transplantation (BMT). This occurred in a 36-year-old woman who received an allogeneic BMT for acute myeloid leukaemia in relapse. At 15 months after BMT, recipient haematopietic and leukaemic cells were found in the bone marrow, which disappeared on withdrawal of immunosuppression. However, severe graft-versus-host disease (GVHD) necessitated the continuation of immunosuppression, leading to the occurrence of PTLD in the liver and lung 12 months afterwards. Fluorescence in situ hybridisation showed that the neoplastic cells were of recipient origin. Although the PTLD also responded completely to withdrawal of immunosuppression, the patient finally died from the complications of GVHD. This case of late onset PTLD post-BMT showed features similar to those in solid organ transplantation, in that the tumour was of recipient origin and responded well to the withdrawal of immunosuppression. Of further interest is that recipient lymphoid regeneration had accompanied autologous haematopoietic regeneration and become a target for subsequent neoplastic transformation.

Acute Disease↗
PubMed2001

Philadelphia (Ph) chromosome-positive chronic myeloid leukaemia relapsing as Ph-negative leukaemia after allogeneic bone marrow transplantation.

Two patients with Philadelphia chromosome-positive (Ph(+)) chronic myeloid leukaemia (CML) relapsed 1.5 and 5 years after allogeneic bone marrow transplantation (BMT). Although the leukaemias were of recipient origin, t(9;22) could no longer be detected using conventional cytogenetics/fluorescence in situ hybridization or molecularly. Both patients responded to immunotherapy with donor lymphocytes/peripheral blood stem cells, although one patient ultimately relapsed again. These patients were similar to the occurrence of Ph(-) leukaemias previously described in Ph(+) CML after treatment with interferon or autologous BMT, and might be relevant in the pathogenesis and monitoring of treatment after BMT in CML.

Adult↗
PubMed2001

Risk of haematological malignancies in HLA-B27 carriers.

Human leucocyte antigen (HLA)-B27 carriers are predisposed to inflammatory and autoimmune diseases. Among 1137 patients with haematological diseases, 59 HLA-B27 carriers were identified. Compared with 18 774 volunteers, the incidence of HLA-B27 was increased in patients with acute leukaemia (relative risk RR = 1.67, P = 0.002), for both acute myeloid leukaemia (AML) (RR) = 1.67, P = 0.007) and acute lymphoblastic leukaemia (ALL) (RR = 1.68, P = 0.094). Of all the HLA-B27 carriers, four patients had ankylosing spondylitis (AS), all with lymphoid malignancies (three ALL, one Hodgkin's disease), whereas no HLA-B27 carriers with myeloid leukaemia had AS symptoms (P = 0.006). This suggests that HLA-B27 carriers may have an increased risk of acute leukaemia and those with concomitant AS may be predisposed to lymphoid malignancies.

Acute Disease↗
PubMed2001

Association of the HLA A2-B46-DR9 haplotype with autoimmune thyroid dysfunction after bone marrow transplantation in Chinese patients.

Autoimmune thyroid disease (AITD) may occur in patients after bone marrow transplantation (BMT). At a median follow-up of 4 years, among 194 allografts and 28 autografts, four patients (three allografts, one autograft) developed AITD. All carried the human leucocyte antigen (HLA) A2-B46-DR9 haplotype, strongly associated with AITD in the Chinese population. No significant thyroid disorder was detected in 190 patients without this haplotype. The frequency of AITD in BMT patients with the HLA A2-B46-DR9 haplotype was 12.5%, with a relative risk of 7.8 times that of non-carriers (P < 0.001). The risk of AITD should be recognized in recipients with high-risk HLA haplotypes, and regular screening might be warranted.

Adult↗
PubMed2001

Primary hepatic lymphoma.

We report the histologic and CT imaging findings of a patient with primary Burkitt's lymphoma of the liver. She presented with a massive, painless abdominal mass. The tumor responded to chemotherapy but the patient died of neutropenic sepsis.

Aged↗
PubMed2001

Primary extramedullary plasmacytoma of the lacrimal gland.

Primary extramedullary plasmacytoma (EMP) of the lacrimal gland is rare. Here we describe the histopathologic and imaging findings in a 77-year-old patient with primary extramedullary plasmacytoma of the lacrimal gland. The usefulness of CD79a in the diagnosis of plasmacytoma and the good response of the tumor to combined surgery and radiotherapy are illustrated. Plamacytoma should be included in the differential diagnosis of lacrimal tumors.

Aged↗
PubMed2001

Presence of potential nickel-responsive element(s) in the mouse MTH1 promoter.

The murine MTH1 gene codes for MTH1, an 8-oxo-2'-deoxyguanosine 5'-triphosphate pyrophosphohydrolase (8-oxo-dGTPase) which hydrolyzes 8-oxo-dGTP, a promutagenic product of reactive oxygen species' attack on the nucleotide pool. This gene is regulated by oxidative stress. Therefore, we hypothesized that MTH1 expression can be affected by carcinogenic nickel(II), known to induce such stress. Three plasmid constructs, carrying different upstream regions of the mouse MTH1 and the chloramphenicol acetyltransferase (CAT) reporter gene, were transiently transfected into NIH 3T3 cells and the CAT protein was measured in nickel(II) acetate-treated and untreated cells. Nickel concentration-dependent increase of CAT protein level was observed for low Ni(II) concentrations, up to 400 microM Ni(II), in cells transfected with pHI103 plasmid (-5969 to +530 of the MTH1 sequence) only. Cells transfected with the pHI104 (-1331 to +530) or pHI108 (-151 to +530) plasmids did not respond to nickel(II) whatsoever. This finding demonstrated that the MTH1 sequence between -5969 and -1331 contained element(s) responsive to nickel(II) treatment. DNA sequencing revealed the presence of AP-1, NF-kappaB, and ATF-1 binding sites in both the -5969 to -1331 and -1331 to +530 regions. In contrast, two (CA)n repeats (-5642 to -5582 and -2078 to -2031), a family of B2 (-5428 to -5247) and B1 (-4559 to -4420) short interspersed repeated elements, and an (AT)n repeat (-5243 to -5230) were identified only in the -5969 to -1331 sequence. The results suggest that up-regulation of murine MTH1 expression by nickel(II) is controlled by the repeat sequences, potential candidates for nickel-responsive elements.

3T3 Cells↗
PubMed2001

Unmanipulated bone marrow transplantation from one-HLA locus mismatched siblings carries high transplant-related mortality in Chinese patients.

BACKGROUND AND OBJECTIVES: We compared the outcome of bone marrow transplantation (BMT) from HLA-identical siblings (MSD) and one HLA-locus mismatched siblings (PMSD) in Chinese patients with hematologic malignancies in terms of transplant-related mortality (TRM) and disease relapse to see whether PMSD can feasibly increase the availability of donors in our population. DESIGN AND METHODS: Medical records of patients who had received a BMT from sibling donors in the Queen Mary Hospital, Hong Kong, from March 1990 to February 2000 were reviewed (MSD 326, PMSD 20). Patients and their donors were matched for HLA-A, -B and DRB1 loci using standard serologic methods as well as polymerase chain reaction-sequence specific primers. All patients received standard anti-microbials and graft -versus host disease (GVHD) prophylaxis including cyclosporin A and a short course of methotrexate. RESULTS: A total of 346 BMT patients were analyzed of whom 326 and 20 patients had received transplants from matched and one locus mismatched siblings, respectively. Patients receiving BMT from PMSD had a significantly higher TRM than those receiving their BMT from MSD (p=0.0016). Six patients received BMT from HLA-DR PMSD: one died 2 months post-BMT as a result of post-transplantation-related lymphoproliferative disease. Fourteen patients received BMT from HLA-A or -B PMSD: 11 of these patients died after a median of 5.6 months (range 0.6-13.7 months) due to severe GVHD (n=5), graft failure (n=2), bleeding (n=1), leukemic relapse (n=2) and thrombotic thrombocytopenic purpura (n=1). Two out of the three survivors had primary graft failure: one of these two required infusion of back-up marrow and the other had autologous regeneration. Patients in the PMSD group were at greater risk of developing severe GVHD than their MSD-recipient counterparts (p<0.001). There was no significant difference in the probability of disease relapse between patients who received BMT from MSD or PMSD. INTERPRETATION AND CONCLUSIONS: BMT from PMSD (especially those with mismatches at HLA class I loci) carried a higher risk of TRM and morbidity than BMT from MSD in our population.

Adolescent↗
PubMed2001

Helper T-lymphocyte precursor frequency predicts the occurrence of graft-versus-host disease and disease relapse after allogeneic bone marrow transplantation from HLA-identical siblings.

BACKGROUND AND OBJECTIVES: Donor helper T-lymphocytes may be involved in graft-versus-host disease (GVHD) and a graft-versus-leukemia effect after bone marrow transplantation (BMT). We assayed donor helper T-lymphocyte precursor frequencies (HTLP(f)) to see whether they could predict the severity of GVHD and disease relapse after transplantation, thereby facilitating donor selection, pre-transplant counselling and modification of GVHD prophylaxis after BMT. DESIGN AND METHODS: Thirty-six consecutive adult BMT recipients and their HLA-identical sibling donors were recruited. HTLP((f)) was measured as a function of interleukin-2 secretion by alloreactive donor T-cells using a limiting dilution assay. Patients were followed prospectively to assess the severity of GVHD and the status of the primary disease after BMT. RESULTS: Eight donors had HTLP((f)) less than or equal to 10(-6); no recipients of these grafts developed severe GVHD after transplantation. Twenty-eight donors had HTLP(f) greater than 10(-6) and 18 recipients of these grafts developed severe GVHD (> or = grade 2) (chi(2) test, p<0.01). Seven donors had HTLP(f) greater than 10(-5) and no recipient had disease relapse. Twenty-nine donors had HTLP(f) less than or equal to 10(-5), 11 recipients of these grafts developed disease relapse (chi(2) test, p=0.08). INTERPRETATION AND CONCLUSIONS: BMT recipients from HLA-identical sibling donors with low (<10(-6)) and high (>10(-5)) HTLP(f) may have a low risk of acute GVHD and disease relapse after transplantation.

Adolescent↗
PubMed2001

Plasma nitric oxide is associated with the occurrence of moderate to severe acute graft-versus-host disease in haemopoietic stem cell transplant recipients.

BACKGROUND AND OBJECTIVES: Nitric oxide (NO) has been implicated as one of the mediators of acute graft-versus-host disease (GVHD) but reports on its measurement during haemopoietic stem cell transplantation (HSCT) in human are scarce. The present study was conducted to measure the plasma NO in HSCT recipients in order to delineate its relationships with acute GVHD. DESIGN AND METHODS: Thirty-nine randomly selected patients undergoing HSCT were recruited. Thirty-one patients received allogeneic transplants (ALLO) from HLA-identical siblings (n=20), haploidentical parent (n=1) and matched unrelated donors (n=10). Eight patients received autologous (AUTO) HSCT. Plasma levels of nitrite/nitrate (NO(2)(-)/NO(3)(-)), the end-product of NO, were measured by chemiluminescence and the results were correlated with the occurrence and severity of acute GVHD. RESULTS: Baseline NO(2)(-)/NO(3)(-) levels before HSCT were similar in the ALLO and AUTO patients (17.4 vs 21.1 microL, p>0.05). Significant increases in plasma NO(2)(-)/NO(3)(-) (> 2 times the baseline level) were found in all 13 patients with acute GVHD > or = grade 2, in 15 out of 18 patients with acute GVHD grade < or = 1 and 3 out of 8 patients receiving autologous HSCT. The increase in NO(2)(-)/NO(3)(-) among the three groups of patients was significantly different (135.5 vs 56.3 vs 36.6 micromol/L, p < 0.001). The average NO production, calculated as the area under the curve, was also significantly differently among the three groups of patients (44.5 vs 30.0 vs 23.8 micromol/L, p < 0.001). INTERPRETATION AND CONCLUSIONS: Plasma NO in HSCT recipients is quantitatively associated with the occurrence of acute GVHD and its role remains to be determined.

Adolescent↗
PubMed2001

[Identification of Amomum villosum, Amomum villosum var. xanthioides and Amomum longiligulare on ITS-1 sequence].

OBJECTIVE: To identify Amomum villosum Lour. and some their adulterants on molecular biology. METHOD: The DNA of Amomum villosum Lour. and some their adulterants were extracted, and amplified using ITS-1 primer. The amplificed DNA were purified and then sequenced by direct PCR sequencing method. RESULT: The ITS-sequence of all of the samples are 248 bp in size. But there are 7 bases in Amomum villosum Lour var. xanthioides (Wall.ex Bak) T.L. Wu et Senjen and 12 hases in Amomum longiligulare T.L. Wu. differing from Amomum villosum Lour. CONCLUSION: The ITS-1 sequence can be used to identify effectively Amomum villosum Lour. and their adulterants.

Amomum↗
PubMed2001

[Clinical application of ultrasonographic indexes for assessment of amniotic fluid volume].

OBJECTIVE: To find the favorable interval of assessment of amniotic fluid volume and the optimal standard for oligohydramnios. METHODS: To determine actual amniotic fluid volume (AAFV) by collecting amniotic fluid during cesarean section and compare it with maximum vertical pocket (MVP) and amniotic fluid index (AFI) in different interval between cesarean section and measurement and test the sensitivity and specificity of MVP and AFI of different standard. RESULTS: The ultrasonographic results were divided into three groups according to the interval between measurement and delivery: within 24 hours group, 24-96 hours group and longer than 96 over hours group. The results of the within 24 hours and 24-96 hours groups were positively correlated with AAFV, while the results of the group longer than 96 hours were not statistically significant. The correlation coefficients were 0.840 and 0.869 for MVP, 0.789 and 0.874 for AFI respectively. The receiver-operator characteristic curve showed that MVP < 4 cm and AFI < 10 cm were superior to any other standards to scan oligohydramnios. The sensitivity of these standards was 0.76 and 0.61, and the specificity was 0.83 and 0.91. CONCLUSION: It is highly recommended to estimate the amniotic fluid of high risk pregnant women, women with MVP < 4 cm or AFI < 10 cm and with a pregnancy week > 40 weeks should be monitered by ultrasonography every four days.

Amniotic Fluid↗