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Biomedical subjects

S K Ma

Publications and source records attributed to S K Ma.

At least 109 records · Page 6Linked to original sources
PubMed1999

Tetraploid acute promyelocytic leukemia with large bizarre blast cell morphology.

We describe a case of atypical acute promyelocytic leukemia (APL) with a tetraploid clone and multiple karyotypic abnormalities in addition to the translocation (15;17)(q22;q21). Microscopically, the leukemic cells were highly heterogeneous in morphology and granularity, being bizarre and large in size compared with classical APL blasts. The patient responded to treatment with chemotherapy and all-trans-retinoic acid, at diagnosis and at relapse 10 months later. He is currently in clinical and molecular remission, 3 years after initial diagnosis. Tetraploidy in association with large and bizarre blasts has not been previously reported in APL. Although tetraploidy and complex karyotypic aberrations confer a poor prognosis in other types of acute myeloid leukemia, in the presence of t(15;17) they did not appear to affect the prognosis, inasmuch as the clinical features and treatment outcome in our case followed those of APL in general.

Adult↗
PubMed1999

Acute myeloid leukemia relapsing as gynecomastia.

Granulocytic sarcoma (GS) is an increasingly common relapse feature of acute myeloid leukemia (AML), late in the disease course or post bone marrow transplantation (BMT). Any solid organ can be affected, and there have been a number of reports of GS in breast tissue in female patients. We present a unique case of GS in a male AML patient, presenting as painless gynecomastia immediately before BMT at advanced disease. Aberrant expression of CD56 was found in the relapsed GS tissue but not in the original AML clone. Twelve months after allogeneic BMT, leukemia relapsed again in the same breast, with normal marrow morphology and full donor chimerism. The lesion failed to respond to donor lymphocyte infusion, chemotherapy and radiotherapy, and disseminated to other subcutaneous tissues.

Adult↗
PubMed1998

Nuclear proteins from liver and kidney bind a 37 bp sequence in the 5' upstream region of the mGAT1 gene.

The mouse GABA transporter (mGAT1) gene has been shown to be exclusively expressed in brain by Northern and Western blot analyses. The interactions between the 5' flanking region of the mGAT1 gene and nuclear proteins from different mouse tissues were studied by means of gel-shift assay. Our results show that nuclear protein factors from non-nervous tissues can specifically recognize a 37 bp sequence that is conserved in the 5' flanking region between the human and mouse GAT1 genes. Similar nuclear protein factors were also found to exist in rat, rabbit and pig.

Animals↗
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

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

Trisomy 5 in two cases of acute monocytic leukemia with hyperdiploid clones.

Although numerical chromosomal aberrations are commonly seen in acute myeloid leukemia (AML), trisomy 5 (+ 5) is very rarely detected. We report two patients, both of whom suffered from acute monocytic leukemia, in which + 5 was found in hyperdiploid clones. A review of the English literature shows 17 additional cases of AML with + 5 in at least one of the abnormal clones, making a total of 19 such cases including ours. Trisomy 5 has been reported in all FAB subtypes of AML except acute promyelocytic leukemia. In the 19 cases identified in this report, + 5 was found in association with other numerical changes (four cases), structural changes (five cases) or both (eight cases). Trisomy 5 as a sole karyotypic abnormality was exceedingly rare (two cases). Its biologic and prognostic significance remains to be determined.

Adult↗
PubMed1998

Analysis of the 5' flanking sequence of the human norepinephrine transporter gene.

The human norepinephrine transporter (NET) gene was cloned and structurally analyzed. The far 5' fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in human brain stem tissue was determined by primer extension analysis. It was found that the gene could be transcribed from multiple starting points. The 5' flanking sequence contains a proximal G-C rich region, one possible GSG element and several SP1 sites. However it does not contain TATA box and CAAT box motifs. Gel shift analysis with nuclear extracts from different tissues of mouse shows that the G-C rich region may be involved in tissue specific expression of the gene.

Animals↗
PubMed1998

Bone marrow necrosis in bone marrow transplantation: the role of MR imaging.

We describe an ALL patient who developed extensive bone marrow necrosis at the time of relapse 2 months after allogeneic bone marrow transplantation from an HLA-identical sibling. The excruciating and diffuse bone pain, fever and precipitous drop in peripheral blood counts were characteristic. This case illustrates the importance of repeat bone marrow biopsies for the diagnosis of disease relapse and the potential application of MR imaging in the assessment of patients with bone marrow necrosis.

Adult↗
PubMed1998

Near-haploid common acute lymphoblastic leukaemia of childhood with a second hyperdiploid line: a DNA ploidy and fluorescence in-situ hybridization study.

Near-haploidy is a rare cytogenetic finding in childhood acute lymphoblastic leukaemia (ALL) and is associated with a poor prognosis. A second hyperdiploid line, occurring presumably by endoreduplication of the near-haploid stemline, is often observed. We present a case of common ALL in relapse characterized morphologically by a dual population of small and large lymphoblasts. Cytogenetic analysis supplemented with fluorescence in-situ hybridization (FISH) studies localized near-haploidy and hyperdiploidy to the small and large blast population respectively. DNA ploidy determination confirmed two abnormal clones with near-haploidy as the predominant one. A novel t(9;12)(q11;q13) was present in the near-haploid clone and was duplicated in the hyperdiploid clone. This finding identified cells bearing near-haploidy to be the clonogenic population following malignant transformation and confirmed endoreduplication as the mechanism for the presence of associated hyperdiploidy.

Child↗
PubMed1998

Malignant lymphoma masquerading as multiple myeloma.

A case of non-Hodgkin's lymphoma with features mimicking that of multiple myeloma is reported. A 67-year-old man presented with lymphadenopathy and the classic constellation of symptoms and signs of multiple myeloma, including generalised bone pain, hypercalcemia and multiple osteolytic lesions on the skeletal survey. However, cervical lymph node biopsy showed diffuse large cell lymphoma and marrow aspirate showed infiltration with lymphoma cells different in both morphology and surface markers to myeloma cells.

Aged↗