Biomedical subjects

Chang-Ki Min

Publications and source records attributed to Chang-Ki Min.

5 recordsLinked to original sources

PubMed2003

Excitation energy transport processes of porphyrin monomer, dimer, cyclic trimer, and hexamer probed by ultrafast fluorescence anisotropy decay.

Femtosecond fluorescence anisotropy measurements for a variety of cyclic porphyrin arrays such as Zn(II)porphyrin m-trimer and hexamer are reported along with o-dimer and monomer as reference molecules. In the porphyrin arrays, a pair of porphyrin moieties are joined together via triphenyl linkage to ensure cyclic and rigid structures. Anisotropy decay times of the porphyrin arrays can be well described by the Förster incoherent excitation hopping process between the porphyrin units. Exciton coupling strengths of 74 and 264 cm(-1) for the m-trimer and hexamer estimated from the observed excitation energy hopping rates are close to those of B800 and B850, respectively, in the LH2 bacterial light-harvesting antenna. Thus, these cyclic porphyrin array systems have proven to be useful in understanding energy migration processes in a relatively weak interaction regime in light of the similarity in overall structures and constituent chromophores to natural light-harvesting arrays.

Biomimetic Materials↗

PubMed2002

Supplemental peripheral blood stem cells to decrease marrow rejection in adult patients with severe aplastic anemia.

Twenty-two multi-transfused patients with a long duration of severe aplastic anemia (SAA) received a transplant from an HLA-matched donor after cyclophosphamide (CY) plus antithymocyte globulin plus procarbazine using CD34(+) enriched blood stem cells + fresh marrow. Peripheral blood stem cells (PBSC) were collected on days 5 and 6 of G-CSF (10 microg/kg/day), and T cells were depleted using an immunoadsorption column (n = 15) or magnetic cell sorting (n = 7). Marrow harvesting was performed 48 hr after the last leukapheresis. Two patients (9.1%) that developed graft failure had a successful engraftment again using unpurged PBSC. Median time to neutrophils > or = 0.5 x 10(9)/l and platelets > or = 20 x 10(9)/l without platelet transfusions were 12 days and 17 days, respectively. Acute graft-versus-host disease (GVHD) grade II occurred in four of 22 patients. No patient developed grade III or IV acute GVHD. Four of the evaluable 21 patients had chronic GVHD. One patient developed extensive disease. Three patients (13.6%) died from CY-induced heart failure, extensive-type chronic GVHD, and sepsis of unknown cause. The Kaplan-Meier estimate of survival was 83.9% (95% CI, 70.1-95.2%) with a median follow-up duration of 33.5 (6-44) months. CD34(+)-enriched PBSC in combination with unmanipulated marrow seem to play a role in overcoming the sensitization to histocompatibility antigens without an apparent increase in GVHD. The stem cell component therapy may be feasible for the high-risk SAA adult patients.

Adolescent↗

PubMed2002

Comprehensive comparison of FISH, RT-PCR, and RQ-PCR for monitoring the BCR-ABL gene after hematopoietic stem cell transplantation in CML.

The reverse transcriptase-polymerase chain reaction (RT-PCR) was compared with fluorescence in situ hybridization (FISH) and real-time quantitative RT-PCR (RQ-PCR) for minimal residual disease (MRD) monitoring in 266 post-transplant bone marrow samples from 78 patients with chronic myelogenous leukemia (CML). The sensitivities of FISH to BCR-ABL positive samples determined by first-round (1st) RT-PCR, second-round (2nd) RT-PCR, and RQ-PCR were 64.2%, 25.8%, and 20.7%, respectively. The BCR-ABL/ABL ratio by RQ-PCR had a mean of 0.000 13 in the 1st RT-PCR-negative samples and 1.42 in the 1st RT-PCR-positive samples (P<0.001), and means of 0.000 39 and 0.51 in the 2nd RT-PCR-negative and -positive samples (P< 0.001). The mean ratios of BCR-ABL/ABL by RQ-PCR were significantly different in N/N (1st/2nd RT-PCR) or N/P and P/P (P<0.001), but not in N/N and N/P, which showed that the discriminative power of RQ-PCR is confined to the 1st RT-PCR level. In this respect, monitoring of the 1st RT-PCR might be useful for estimating normalized BCR-ABL levels after transplantation. Nested RT-PCR was of limited use, as RQ-PCR quantified the BCR-ABL transcripts in 60 (91%) of 66 samples determined to be negative by 2nd RT-PCR. FISH was significantly correlated with RQ-PCR in FISH-positive samples (n=24, r=0.79, P=0.001). An increase of FISH preceded that of RQ-PCR in a few cases with molecular relapse. By analyzing a large number of samples post-transplant, we found that RQ-PCR might be the most useful assay for MRD monitoring; however, FISH and RT-PCR were found to be useful complementary tools.

Bone Marrow↗

PubMed2002

Influence of karyotype on outcome of allogeneic bone marrow transplantation for adults with precursor B-lineage acute lymphoblastic leukaemia in first or second remission.

The prognostic relevance of karyotype has been established in adult acute lymphoblastic leukaemia (ALL) patients treated with chemotherapy but not definitively evaluated in an allogeneic bone marrow transplantation (BMT) setting. To determine the factors affecting the outcome of allogeneic BMT for adults with precursor B-lineage ALL in first or second complete remission (CR), a total of 41 consecutive patients with a successful karyotype were enrolled in this study. There were 21 men and 20 women with a median age of 27 (15-43) years. The distribution of French-American-British (FAB) subtypes was as follows: L1 (n = 26), L2 (n = 15). Unfavourable karyotypes (n = 12) were defined as Ph+ or t(4;11). Disease status at the time of transplant was first CR (n = 35) or second CR (n = 6). With a median follow-up of 36 months, the 3-year probabilities of relapse and disease-free survival (DFS) were 36.3 +/- 8.4% and 57.3 +/- 8.4% respectively. Potential variables predicting worse relapse and DFS were FAB subtype (L2), extramedullary involvement, pre-BMT status (second CR), unfavourable karyotype and type of graft-versus-host disease (GVHD). Further multivariate analysis showed that karyotype and pre-BMT status were independently associated with relapse and DFS. In addition, chronic GVHD was found to be significantly associated with a lower relapse rate.

Adolescent↗

PubMed2002

Two cases of disseminated mucormycosis in patients following allogeneic bone marrow transplantation.

We describe two cases of disseminated mucormycosis following allogeneic bone marrow transplantation (BMT). Both patients were suffering from chronic graft-ver-sus-host disease (GVHD) and treated with prolonged administration of corticosteroid. In both cases, the initial symptoms were high fever and left flank pain. Involved organs were the spleen, right kidney and the right lung in one case, and the spleen and the brain in the other. The diagnosis was confirmed by pathology after splenectomy. One patient, in whom the immunosuppressants could be discontinued, was treated with prolonged conventional and liposomal amphotericin B and 5-fluorocytosine. The other, in whom the immunosuppressants could not be discontinued due to extensive GVHD, was unresponsive to amphotericin B, and eventually died from the fungal infection. Although mucormycosis, especially the disseminated form thereof is infrequent, it should be considered in high-risk patients because early diagnosis and timely therapy combining antifungal drug or surgery and reduction of immunosuppression appear to improve the prognosis.

Adult↗