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Biomedical subjects

S K Ma

Publications and source records attributed to S K Ma.

At least 55 records · Page 3Linked to original sources
PubMed2001

Derivative (1;18)(q10;q10): a recurrent and novel unbalanced translocation involving 1q in myeloid disorders.

We report two cases of hematological malignancies, comprising a case of myelodysplastic syndrome (MDS) that rapidly evolved into acute myeloid leukemia, and a case of myeloproliferative disorder (MPD), in which der(1;18)(q10;q10) was found as the sole acquired karyotypic abnormality. This observation indicates that the unbalanced translocation is a recurrent aberration in myeloid disorders. To the best of our knowledge, centromeric fusion between long arms of chromosomes 1 and 18, leading to a normal chromosome 18 substituted with a der(1;18) chromosome, is novel and has not been described in cancer. Mechanistically, either trisomy 1q or monosomy 18p that results from the translocation may potentially contribute to leukemogenesis. Finally, chromosomes with large constitutive heterochromatin bands such as chromosome 1 may be at risk of centromeric instability and be predisposed to centromeric fusion with other chromosomes.

Acute Disease↗
PubMed2001

Primary CD56 positive lymphomas of the gastrointestinal tract.

BACKGROUND: Primary CD56 positive lymphoma of the gastrointestinal (GI) tract is rare. Genotypically, these tumors can be classified into natural killer (NK)-like T-cell lymphoma or NK cell lymphoma by the presence or absence of T-cell receptor (TCR) gene rearrangement. However, they have a considerable degree of morphologic and immunophenotypic overlap, making a definitive diagnosis difficult. METHODS: The clinicopathologic features of three patients with primary CD56 positive lymphoma of the small and large bowel are presented. This is followed by a review of the English literature from 1966 to the present. RESULTS: All patients had CD56 positive/CD3epsilon positive disease on paraffin section. Two patients were positive for Epstein-Barr virus-encoded early nuclear RNAs (EBER) according to in situ histochemistry results and were negative for TCR gene rearrangement, consistent with primary NK lymphoma of the GI tract. The other patient was EBER negative with rearranged TCR, consistent with NK-like T-cell lymphoma. There was no clinical or histologic evidence of enteropathy in any of the patients. The major presenting symptoms included fever, weight loss, and intestinal perforation. All patients died between 1 week and 6 months after diagnosis despite undergoing surgery and intensive chemotherapy. CONCLUSIONS: These results, together with a literature review, suggest that primary NK cell lymphoma of the GI tract may be considered a distinct clinicopathologic entity. Both primary NK and NK-like T-cell lymphoma pursue an aggressive clinical course. EBER and TCR gene rearrangement are useful in distinguishing NK cell lymphoma from NK-like T-cell lymphoma, particularly when frozen tissue is not available for immunophenotyping.

Adult↗
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

Norepinephrine transporter (NET) is expressed in cardiac sympathetic ganglia of adult rat.

The sympathetic nervous system plays a cardinal role in regulating cardiac function through releasing the neurotransmitter norepinephrine (NE). In comparison with central nervous system, the molecular mechanism of NE uptake in myocardium is not clear. In present study, we proved that in rat the CNS type of NE transporter (NET) was also expressed in middle cervical-stellate ganglion complex (MC-SG complex) which is considered to control the activity of heart, but not expressed in myocardium. The results also showed that NET expression level in right ganglion was significantly higher than in the left, rendering the greater capacity of NE uptake in right ventricle, a fact which may contribute to the maintenance of right ventricular function under pathologic state.

Animals↗
PubMed2001

Characterization of additional genetic events in childhood acute lymphoblastic leukemia with TEL/AML1 gene fusion: a molecular cytogenetics study.

TEL/AML1 gene fusion that results from a cryptic t(12;21) is the most common genetic aberration in childhood B-lineage acute lymphoblastic leukemia (ALL). While the translocation may initiate the leukemic process, critical secondary genetic events are currently believed to be pivotal for leukemogenesis. We investigated 12 cases of childhood ALL with TEL/AML1 gene fusion by fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) and documented additional or secondary genetic changes in seven patients (58%). Three patients showed extra copies of chromosome 21 including a case in which the trisomy 21 (+21) clone was distinct from the one harboring TEL/AML1 gene fusion. Interestingly, one patient without +21 showed amplification of the AML1 gene on chromosome 21q, supporting the contention that AML1 amplification may be an important additional genetic event. Gene expression study by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) in two of these four patients showed an increase in AML1 transcripts that paralleled the increase in gene copy number. Deletion of the normal TEL allele was detected in two patients, with one of them showing loss of chromosome 12 together with duplication of the der(12)t(12;21). Finally, one patient showed duplication of the fusion signal. Our findings confirm that additional or secondary genetic changes including AML1 amplification are commonly encountered in childhood ALL with TEL/AML1 gene fusion, which are envisaged to play significant roles in disease progression.

Adolescent↗
PubMed2001

Therapy-related myelodysplastic syndrome of recipient origin after allogeneic bone marrow transplantation for acute lymphoblastic leukaemia.

Therapy-related myelodysplastic syndrome (t-MDS) is a very rare complication of allogeneic bone marrow transplantation (BMT). A woman with T acute lymphoblastic leukaemia (T-ALL) received an allogeneic BMT from a donor with the beta-thalassaemic trait. Five years after BMT, the red cell indices returned to normal after an initial conversion to microcytosis, implying autologous haematopoietic regeneration. Seven years after BMT, thrombocytopenia developed and marrow examination confirmed t-MDS, with a characteristic karyotype 46,XX,inv(3)(q21;q26), del(5)(q13),add(17)(p11). Retrospective molecular analysis of donor/recipient chimaerism showed gradual regeneration of recipient cells after BMT, culminating at the time of t-MDS. Our findings illustrate the unusual occurrence of t-MDS after allogeneic BMT. Re-emergence of recipient haematopoesis may herald the development of a haematological malignancy different from the original neoplastic clone for which the BMT was performed.

Adolescent↗
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

Haemoglobin Q-Thailand and hereditary spherocytosis in a Chinese family.

A Chinese family with concurrent hereditary spherocytosis (HS) and haemoglobin (Hb) Q-Thailand is described. The Hb Q-Thailand mutation was found on the remaining alpha1 globin gene on a chromosome 16 containing the (-alpha 4.2) deletion. Active haemolysis in members of this family is segregated with the HS phenotype, and the Hb Q-Thailand in the heterozygous state does not seem to show any modulating effect on HS.

Adult↗
PubMed2001

Haemoglobin H disease due to (--SEA) alpha-globin gene deletion and alpha2-codon 30 (DeltaGAG) mutation: a family study.

A Chinese family in which two siblings suffer from haemogloblin (Hb) H disease due to (--SEA) alpha-globin gene deletion and alpha2-codon 30 (DeltaGAG) mutation is described. Both siblings are transfusion-independent and have survived to adulthood. In contrast to previous report of hydrops fetalis associated with zeta-alpha-thal-1 and alpha2-codon 30 (DeltaGAG) mutation, the zeta-globin genes are intact in the two siblings, which most probably alleviates the gamma-chain excess and protects the fetus from severe anaemia. Correlation of genotype with phenotype in Hb H disease is important for genetic counselling, especially in the antenatal setting.

Adult↗
PubMed2001

Should we screen for globin gene mutations in blood samples with mean corpuscular volume (MCV) greater than 80 fL in areas with a high prevalence of thalassaemia?

AIMS: To investigate whether it is worthwhile, in areas where thalassaemia is common, to screen for globin gene mutations in subjects with a mean corpuscular volume (MCV) above 80 fL, especially in partners of known thalassaemia carriers. METHODS: Blood samples from 95 subjects with MCV between 80 and 85 fL were screened for the presence of alpha globin gene mutations and the haemoglobin (Hb) E mutation. RESULTS: Thirty four subjects harboured globin gene mutations. Of these, 31 had deletions of one alpha globin gene, one had Hb Constant Spring, and three had Hb E mutations. CONCLUSION: Based on the above figures and known prevalence rates of thalassaemia carriers, it would seem worthwhile to screen for globin gene mutations in partners of known thalassaemia carriers, regardless of MCV, to identify pregnancies at risk of Hb H disease or Hb E/beta thalassaemia.

China↗
PubMed2001

Nodal plasmacytoma with significant paraproteinaemia.

We present a case of primary nodal plasmacytoma in an elderly Chinese woman that was associated with significant paraproteinaemia and paraproteinuria. Clinical and laboratory features of the patient satisfied Durie's criteria for the diagnosis of multiple myeloma. The present case was unusual in two aspects. Firstly, there was no evidence of clonal plasma cell proliferation elsewhere in the body after extensive radiological investigations, repeated bone marrow examinations, and polymerase chain reaction for immunoglobulin gene rearrangement study. Secondly, the clinical behaviour was indolent despite the large amount of paraprotein production, and showed satisfactory disease control with local radiotherapy. The differential diagnoses of plasmacytosis in the lymph node are also discussed.

Aged↗
PubMed2001

Disseminated hepatosplenic mycobacterial infection masking myeloproliferative diseases as leukemoid reaction: a diagnostic pitfall.

The distinction of myeloproliferative disease (MPD) from leukemoid reactions due to reactive causes can be difficult. In the presence of simultaneous occurrence of MPD and an established infection, only the demonstration of a clonal marker or prolonged observation can substantiate the diagnosis. We present three cases of MPD presenting as leukemoid reaction due to disseminated hepatosplenic mycobacterial sepsis. There appeared to be an association between MPD and reduced resistance to mycobacterial infection. Clinicians and hematologist should be aware of such a predisposition and possible dual pathology for proper diagnosis, therapy and monitoring of both the infection and the myeloproliferation.

Adult↗
PubMed2001

The predictive parameters of erythropoietin hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis.

BACKGROUND: The present study was aimed at investigating the predictive parameters of erythropoietin (epoetin) hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis (CAPD). METHODS: We studied 40 patients with end-stage renal disease who had been receiving CAPD for at least 6 months and epoetin therapy for at least more than 2 months. Pearson's simple correlation and multiple stepwise linear regression analysis was used to discover what parameter can predict epoetin resistance. We expressed epoetin resistance index (ERI) as weekly epoetin dose/hematocrit/body weight'. The dose of epoetin is titrated by about 25% every 2 to 4 weeks to maintain a target hematocrit level between 33% and 36%. RESULTS: We analyzed the relationship between ERI and other predictive parameters by Pearson's correlation. These results showed ERI has a statistically significant correlation with transferrin saturation (TS) (r = -0.327, p = 0.042), total weekly Kt/Vurea (r = -0.423, p = 0.018), serum albumin level (r = -0.458, p = 0.003), normalized protein catabolic rate (nPCR) (r = -0.479, p = 0.006), normalized protein equivalent of total nitrogen appearance (nPNA) (r = -0.488, p = 0.005) and serum C-reactive protein (CRP) (r = 0.332, p = 0.036). Regression analysis was performed using stepwise linear regression for multiple variables to discover the most independent variable which is correlated with ERI. ERI was entered as a dependent variable, whereas the other parameters (age, duration of peritoneal dialysis, serum albumin level, CRP, serum ferritin, total weekly Kt/Vurea, nPCR, nPNA, serum iPTH, serum aluminium, TS) were entered as independent variables. This analysis showed CRP is the most significant variable and, if CRP is excluded, nPNA is the significant variable. CRP has a statistically significant correlation with serum albumin level (r = -0.418, p = 0.007) and total weekly Kt/Vurea (r = -0.366, p = 0.043). High CRP group has more increased level of ERI (p < 0.05), age (p < 0.05) and serum creatinine level (p < 0.05) than normal control, but more decreased level of serum albumin (p < 0.01) and serum iron levels (p < 0.05). CONCLUSION: These results indicate that CRP is the most important predictor of epoetin hyporesponsiveness.

Adult↗
PubMed2001

Percutaneous catheterization of the internal jugular vein for hemodialysis.

OBJECTIVES: The present study was aimed at evaluating the clinical experiences in the internal jugular venous catheterization for hemodialysis. METHODS: We retrospectively analyzed the data on internal jugular venous catheterization at Chonnam National University Hospital from May 2000 to February 2001. RESULTS: There were 132 uremic patients with a total of 150 attempts of internal jugular cannulation. Overall success rate was 90.9% with average puncture trials of 2.3 +/- 2.1. 124 (82.7%) of the catheterization attempts were made on the right side and 26 (17.3%) were made on the left. The catheters were left in place from 2 to 87 days with an average of 19.5 +/- 15.3 days per catheter. The dialysis sessions per catheter were from 2 to 58 with an average of 11.3 +/- 6.8. The mean blood flow during hemodialysis immediately after catheterization was 213.4 +/- 42.2 ml/min. Thirty two (21.3%) patients had early complications. These included carotid artery puncture (11.3%), local bleeding (4.7%), local pain (3.3%), neck hematoma (0.7%) and malposition of the catheter (1.3%). Seventeen (11.3%) patients had late complications. These included fever or infection (11.3%), inadequate blood flow rate (3.3%) and inadvertent withdrawal (2.0%). There was no catheter-related mortality. CONCLUSIONS: Our experiences revealed that the internal jugular vein catheterization is relatively safe and efficient for temporary vascular access for hemodialysis.

Adolescent↗