Biomedical subjects

N Y Lee

Publications and source records attributed to N Y Lee.

At least 19 recordsLinked to original sources

PubMed2006

Rapid helper T-cell recovery above 200 x 10 6/l at 3 months correlates to successful transplant outcomes after allogeneic stem cell transplantation.

The current study evaluates the role of quantitative measurement of peripheral lymphocyte subsets, especially CD4+ helper T-cell recovery, in predicting transplant outcomes including overall survival (OS) and non-relapse mortality (NRM) after allogeneic stem cell transplantation. A total of 69 allogeneic recipients were included with following diagnoses: acute myeloid leukemia 42, acute lymphoblastic leukemia 5, chronic myeloid leukemia 15, non-Hodgkin's lymphoma 5 and high-risk myelodysplastic syndrome 2. The peripheral lymphocyte subset counts (CD3+ T cells, CD3+4+ helper T cells, CD3+8+ cytotoxic T cells, CD19+ B cells, and CD56+ natural killer cells) were measured at 3, 6 and 12 months. The CD4+ helper T-cell reconstitution at 3 months was strongly correlated with OS (P<0.0001), NRM (P=0.0007), and opportunistic infections (P=0.0108) at the cutoff value of 200 x 10(6)/l CD4(+) helper T cells. Rapid CD4+ helper T-cell recovery was also associated with a higher CD4+ helper T-cell transplant dose (P=0.006) and donor type (P<0.001). An early CD4+ helper T-cell recovery at 3 months correlated with a subsequent faster helper T-cell recovery until 12 months, yet not with B-cell recovery. In a multivariate analysis, rapid recovery of CD4+ helper T cells at 3 months was a favorable prognostic factor together with higher CD34+ cell transplant dose in terms of OS (P=0.001) and NRM (P=0.005).

Adolescent↗

PubMed2006

Prognostic significance of platelet recovery pattern after allogeneic HLA-identical sibling transplantation and its association with severe acute GVHD.

Thrombocytopenia (TP) is a frequent complication after allogeneic stem cell transplantation (SCT) and regarded as a poor prognostic factor when assessed beyond day 100. However, little is known about the clinical significance of the platelet recovery pattern before chronic graft-versus-host disease (GVHD) develops. Eighty-five patients undergoing HLA-identical sibling SCT were stratified according to their platelet recovery pattern between day +30 and +90 and the transplant outcomes analyzed, along with the association of each component of the acute GVHD grading system. Fifteen patients (18%) were classified with persistent TP, 33 patients (39%) with unstable TP, and 37 patients (43%) as non-TP. Persistent TP, which was strongly associated with severe acute GVHD (P<0.001), exhibited the worst 2-year OS (P<0.0001) and highest NRM (P<0.0001) and opportunistic infection rates (P<0.0001). In multivariate analyses, the platelet recovery pattern was identified as an independent prognostic factor (P=0.02) together with the disease risk (P=0.02) in terms of OS, and the only independent prognostic factor in terms of NRM (P=0.005) and the incidence of infectious events (P<0.001). Persistent TP was strongly associated with the development of extensive chronic GVHD (P=0.03). The platelet recovery pattern between day +30 and +90 can be used to predict the prognosis of SCT recipients.

Adolescent↗

PubMed2006

Pulmonary TB and NTM lung disease: comparison of characteristics in patients with AFB smear-positive sputum.

OBJECTIVE: To compare the clinical and radiographic features of pulmonary tuberculosis (PTB) and non-tuberculous mycobacteria (NTM) lung disease in patients with acid-fast bacilli (AFB) positive sputum specimens. DESIGN: The initial clinical and radiographic features of 229 PTB patients were compared with those of 70 patients with NTM lung disease. The most commonly involved organisms in the NTM lung disease cases were Mycobacterium avium complex (n = 38, 54%) and M. abscessus (n = 26, 37%). RESULTS: Clinical and radiographic findings that were more common in patients with NTM lung disease than in PTB patients were: older age (P < 0.001), non-smoker (P < 0.001), history of previous TB treatment (P < 0.001), absence of pleural effusion (P = 0.017), involvement of middle and/or lower lung zones (P = 0.007), and bilateral disease (P = 0.005). Multivariate analysis showed that older age (> or = 40 years), non-smoker, previous TB treatment, absence of pleural effusion and involvement of middle and/or lower lung zones were significant independent predictors for NTM lung disease. CONCLUSIONS: There is considerable overlap in the clinical and radiographic appearances of PTB and NTM lung disease. The isolation and identification of causative organisms are mandatory for a correct diagnosis in patients with AFB-positive sputum specimens.

Coloring Agents↗

PubMed2005

Protective role of interleukin-10 promoter gene polymorphism in the pathogenesis of invasive pulmonary aspergillosis after allogeneic stem cell transplantation.

The current study attempted to evaluate the association between the IL-10 promoter gene single nucleotide polymorphism (SNP) and invasive pulmonary aspergillosis (IPA) after allogeneic stem cell transplantation (SCT) in 105 patients. Three single-nucleotide polymorphisms were investigated in the proximal region of the IL-10 promoter gene (-1082/-819/-592). Two haplotypes (1082*A/819*T/592*A [ATA] and 1082*A/819*C/592*C [ACC]) were found in the current study. The overall incidence of IPA was estimated as 14.1+/-4.5% with a median onset at 186 days post-transplant (62 approximately 405 days). An increased occurrence of IPA was noted dependent on the IL-10 haplotype (0% vs 11.5+/-6.4% vs 19.7+/-7.7% for ACC/ACC vs ATA/ACC vs ATA/ATA haplotype, P=0.0307 when comparing ACC with non-ACC haplotype). In a multivariate survival analysis using Cox's proportional hazard model, the IL-10 promoter gene SNPs were identified as an independent predictive factor for the development of IPA (P=0.012, hazard ratio (HR) 9.3), along with an histocompatibility leukocyte antigen (HLA)-identical donor (P=0.005, HR 16.3), the CD34+ cell dose transplanted (P=0.004, HR 26.5), and time-dependent chronic graft-versus-host disease (GVHD; P=0.049, HR 16.0). The IL-10 ACC haplotype was found to have an apparent protective role in the development of IPA after allogeneic transplantation, regardless of HLA-disparity or chronic GVHD.

Adolescent↗

PubMed2005

Recovery rate of NTM from AFB smear-positive sputum specimens at a medical centre in South Korea.

OBJECTIVE: To investigate the recovery rate of non-tuberculous mycobacteria (NTM) from acid-fast bacilli (AFB) smear-positive sputum specimens at a tertiary care medical centre in South Korea with a high pulmonary tuberculosis (PTB) burden. DESIGN: Retrospective analysis of data from AFB smear- and culture-positive sputum specimens collected between January 1998 and December 2001. RESULTS: Over 4 years, 1328 sputum specimens collected from 616 patients were AFB smear- and culture-positive. NTM were recovered from 9.1% (121/1328) of the smear-positive sputum specimens, and from 8.1% (50/616) of patients with smear-positive sputum. NTM were isolated at least twice in 94% (47/50) of the patients from whom NTM was recovered. The most common organism found was Mycobacterium avium complex, followed by M. abscessus. CONCLUSION: These results suggest that a substantial proportion of patients at a tertiary care medical centre in South Korea with AFB smear-positive sputum specimens may have NTM lung disease rather than PTB.

Adult↗

PubMed2004

A pilot study of cytoreductive chemotherapy combined with infusion of additional peripheral blood stem cells reserved at time of harvest for transplantation in case of relapsed hematologic malignancies after allogeneic peripheral blood stem cell transplant.

Reharvesting leukocytes from donors for a donor leukocyte infusion (DLI) is inconvenient and occasionally impossible in case of unrelated donors. It is well known that the effect of a growth factor-primed DLI is comparable to that of a nonprimed DLI. In total, 42 patients with hematologic malignancies and a high risk of relapse were allocated, on an intent-to-treat basis, a peripheral blood stem cell transplantation (PBSCT) from HLA-matched sibling donors, and then at the time of harvest, additional peripheral blood stem cells (PBSCs) were also reserved for a therapeutic primed DLI in case of relapse. In all, 12 patients who relapsed after allogeneic PBSCT were treated with mainly cytarabine-based chemotherapy followed by a cryopreserved PBSC infusion. The median dose of CD3+ and CD34+ cells for the primed DLIs was 1.43 x 10(8)/kg and 4.75 x 10(6)/kg, respectively. Six of the 12 relapsed patients exhibited a complete response after the primed DLI, plus their 1-year survival rate was 33%. The new development or progression of graft-versus-host disease after a primed DLI was observed in 50% of the patients. Overall, the survival at 1 year was 16.7%. Accordingly, the induction of a graft-versus-leukemia effect through a primed DLI, using additional PBSCs reserved at the original time of harvest, would appear to be feasible for patients with relapsed hematologic malignancies. Furthermore, this approach is also more convenient for donors.

Adoptive Transfer↗

PubMed2004

Risk factors for late cytomegalovirus infection after allogeneic stem cell transplantation using HLA-matched sibling donor: donor lymphocyte infusion and previous history of early CMV infection.

An increased incidence of late cytomegalovirus (CMV) infection has been reported during the last decade since the introduction of ganciclovir (GCV) prophylaxis or GCV pre-emptive therapy. Given that a donor lymphocyte infusion (DLI) can induce more severe GVHD, this may predispose a patient to late CMV infection. In all, 64 patients (median age 36, M/F 38/26) underwent allogeneic stem cell transplantation (SCT) using a matched sibling donor with bone marrow (n=9) or peripheral blood stem cells (n=55). The overall incidence of CMV infection, early and late CMV infection was 46.9 (30/64), 42.2 (27/64), and 16.4% (9/55), respectively. Early CMV infection was treated with GCV pre-emptive therapy that produced a 92.6% success rate. Among the 20 patients who received 35 DLIs, late CMV infection developed in eight (42.1%) of 19 evaluable cases with a median onset at 127 days post transplant. Risk factors for late CMV infection in a logistic regression analysis included DLIs (P=0.001) and a previous history of CMV infection (P=0.006). In conclusion, late CMV infection was strongly associated with DLIs and a previous history of early CMV infection. Accordingly, extended surveillance of CMV antigenemia is recommended for patients receiving DLIs or who have a previous history of CMV infection.

Adult↗

PubMed2003

Effect of infusing lactoferrin hydrolysate into bovine mammary glands with subclinical mastitis.

The therapeutic effect of administering lactoferrin hydrolysate (LFH) into the mammary glands of cows with subclinical mastitis was evaluated. Seven millilitres of a preparation of LFH (7% protein) was infused into 35 quarters of 25 cows with subclinical mastitis. The numbers of bacteria in the milk from infected quarters decreased, and bacteria disappeared by the 14th day after the administration of LFH. The mean somatic cell counts (SCC) peaked one day after administration of LFH and the counts were significantly p < 0.01) decreased on days 7, 14 and 21 compared to those before the administration of LFH. The mean lactoferrin concentration in the milk peaked on days 2 or 3 and then gradually decreased to day 14, returning to the level before the administration of LFH. It appears that administration of LFH may have a therapeutic effect when infused into the quarters of cows with subclinical mastitis.

Animals↗

PubMed2003

Impact of transplanted CD34+ cell dose in allogeneic unmanipulated peripheral blood stem cell transplantation.

The impact of the CD34+ cell dose on chronic graft-versus-host disease (cGVHD) and the clinical outcome was analyzed in 41 consecutive adult patients submitted to allogeneic peripheral blood stem cell transplantation from HLA-identical siblings. The patients were classified into 'low' or 'high' CD34+ cell dose groups based on whether they received less or more than a median CD34+ cell dose of 10.5 x 10(6)/kg, respectively. There was a significant difference in the incidence of extensive cGVHD (low vs high group, 25.0 vs 66.7%, P=0.021) and relapse (47.6 vs 20.0%, P=0.049) between the two groups. With a median follow-up of 335 days, the 3-year survival estimate for the whole population was 47.9%, while that for the low and high groups was 29.9 and 67.8%, respectively (P=0.0434). An inverse relation was noted between the relapse rate and the incidence of extensive cGVHD (P=0.043). It would appear reasonable that the optimal dose of CD34+ cells should be determined based on the disease status or aggressiveness of the malignant cells in each patient. Yet, in the case of patients with a high risk of relapse, transplantation with a CD34+ cell dose of >10.5 x 10(6)/kg would seem to be acceptable to minimize the risk of relapse.

Adolescent↗

PubMed2001

Carriage of antibiotic-resistant pneumococci among Asian children: a multinational surveillance by the Asian Network for Surveillance of Resistant Pathogens (ANSORP).

To investigate the nasal carriage of antibiotic-resistant pneumococci by children, anterior nasal swabs were done for 4963 children <5 years old in 11 countries in Asia and the Middle East. In total, 1105 pneumococci isolates (carriage rate, 22.3%) were collected, 35.8% of which were found to be nonsusceptible to penicillin. Prevalence of penicillin nonsusceptibility was highest in Taiwan (91.3%), followed by Korea (85.8%), Sri Lanka (76.5%), and Vietnam (70.4%). Penicillin resistance was related to residence in urban areas, enrollment in day care, and a history of otitis media. The most common serogroups were 6 (21.5%), 23 (16.5%), and 19 (15.7%). The most common clone, as assessed by pulsed-field gel electrophoresis, was identical to the Spanish 23F clone and to strains of invasive isolates from adult patients. Data in this study documented the high rate of penicillin or multidrug resistance among isolates of pneumococci carried nasally in children in Asia and the Middle East and showed that this is due to the spread of a few predominant clones in the region.

Anti-Bacterial Agents↗

PubMed2001

Production of recombinant bovine lactoferrin N-lobe in insect cells and its antimicrobial activity.

Lactoferrin is a multifunctional, iron-binding glycoprotein found in physiological fluids of mammals. In the present study, a gene encoding the N-terminal half (N-lobe) of bovine lactoferrin was cloned and expressed in cultured insect cells using a baculovirus expression system. One mutation was found in the lactoferrin N-lobe gene, but it resulted in no amino acid substitution. The recombinant lactoferrin N-lobe was secreted into the culture medium and partially purified by means of an immobilized heparin column. The recombinant lactoferrin N-lobe secreted was not glycosylated, but it possessed antimicrobial activity toward Escherichia coli O111. The recombinant product synthesized and accumulated in the host cells exhibited greater electrophoretic mobility on SDS-PAGE than the secreted product and showed no potency to inhibit the growth of bacteria. It is thought that the product accumulated intracellularly lacks antimicrobial ability due to its degradation in the host cells or due to disruption of the active conformation.

Animals↗

PubMed2001

Image reconstruction using the wavelet transform for positron emission tomography.

We conducted positron emission tomography (PET) image reconstruction experiments using the wavelet transform. The Wavelet-Vaguelette decomposition was used as a framework from which expressions for the necessary wavelet coefficients might be derived, and then the wavelet shrinkage was applied to the wavelet coefficients for the reconstruction (WVS). The performances of WVS were evaluated and compared with those of the filtered back-projection (FBP) using software phantoms, physical phantoms, and human PET studies. The results demonstrated that WVS gave stable reconstruction over the range of shrinkage parameters and provided better noise and spatial resolution characteristics than FBP.

Algorithms↗

PubMed2001

Epidemiological usefulness of anti-opacity factor antibody screening in schoolchildren.

The presence of the anti-opacity factor (anti-OF) antibody (Ab) in the serum used for identifying the OF antigen (Ag) type represents previous or current infection with group A streptococci (GAS) of the OF Ag type. Throat cultures were taken from 172 elementary schoolchildren in Chinju, Korea, and venous blood samples were collected at the same time to screen for the frequency of the anti-OF Ab. After isolation of GAS, the OF Ag of each GAS was identified by inhibition of the opacity reaction with recognized anti-OF sera. The anti-OF Abs in the sera were screened with the six most common OF Ag types. OF22 and OF28 were high in prevalence (28.2 and 20.5%, respectively) among OF Ag types, while anti-OF types 4, 28, and 22 were frequently identified (39.5, 29.7, and 15.7%, respectively) in the sera. Thirty-two of 39 (82.1%) OF Ag-producing GAS carriers, 25 of 34 (73.5%) GAS carriers not producing OF Ag, and 72 of 99 (72.7%) throat culture-negative children harbored the anti-OF Ab. Forty-five (26.2%) of 172 children had two different anti-OF Abs, and 11 (6.4%) had more than three anti-OF Abs. Seventy-five percent of 172 elementary schoolchildren were shown to be previously or currently infected with GAS. The percentages of children positive for the anti-OF Ab were very high regardless of the result of throat culture or OF Ag production of GAS. We could also demonstrate (i) that the prevalent strains of GAS changed according to the time span by determining the difference between the frequencies of OF Ag and anti-OF Ab and (ii) that repeated infections were not uncommon in schoolchildren, as one-third had more than two different anti-OF Abs.

Antibodies, Bacterial↗

PubMed2001

Pseudomonas aeruginosa as a potential cause of antibiotic-associated diarrhea.

Although Pseudomonas aeruginosa is not generally considered as a cause of antibiotic-associated diarrhea, several cases of diarrhea caused by P. aeruginosa have been reported. We experienced seven cases of nosocomial diarrhea presumably caused by P. aeruginosa, which was the predominant organism isolated from stool cultures. Clostridium difficile toxin was also positive in one patient. No other potential or recognized enteropathogens were identified from stools. All patients had underlying diseases and had been receiving antibiotics before the diarrheal onset. All of the seven P. aeruginosa isolates were resistant to previously given antibiotics. Diarrhea stopped three days after withdrawal of probable offending antibiotics without specific treatment in two patients. The other five patients having continuous diarrhea despite withdrawal of probable offending antibiotics, were successfully treated with antipseudomonal agents. The median duration of diarrhea after the initiation of treatment was 6.3 days. These data suggest that P. aeruginosa can be a potential cause of antibiotic-associated diarrhea. Further investigations are warranted to evaluate the possible etiologic role of P. aeruginosa in antibiotic-associated diarrhea.

Adult↗

PubMed2000

Skin temperature and skin blood flow affect bioelectric impedance study of female fat-free mass.

PURPOSE: This study examined the effects of skin temperature (Ts) and skin blood flow (SKBF) on bioelectrical impedance (BIA) measurements of body composition in healthy young females. METHODS: The Lukaski (FFM(LUK)) and Guo (FFM(GUO)) BIA equations for measuring female fat-free mass (FFM) were used. All subjects (N = 20, age = 18-22 yr) underwent the following measurements under three ambient temperatures (T(amb)): Ts and SKBF for the calf, thigh, biceps, and chest; oral temperature (T(OR)); and the BIA measures of resistance (R) and reactance (Xc). The three T(amb) were 17, 25, and 35 degrees C which were considered as cold (CT), neutral (NT), and hot (HT) conditions, respectively. Their underwater weighing (UWW), lung residual volume, and skinfold thickness were measured in the NT. Data were analyzed using repeated measures of ANOVA and Tukey post-hoc test. RESULTS: We observed that in the CT mean SKBF and Ts decreased (P < 0.05) and R and Xc increased (P < 0.05), compared with those in both NT and HT. However, in the HT both SKBF and Ts increased and R deceased, but Xc remained unchanged relative to the NT. In these subjects, a net change in Ts of 17 degrees C resulted in a net change in the BIA measure of R of 46 ohms or 2.5 ohms per degree C. These changes affected the estimate of FFM(LUK) between CT, NT, and HT, but not the estimate of FFM(GUO) Regarding the two BIA equations for estimating FFM, the Guo equation underestimated FFM(UWW) (P < 0.05) in the CT, NT, and HT, and the Lukaski equation underestimated FFM(UWW) (P < 0.05) only in the CT, compared with that in the UWW technique. CONCLUSIONS: Ambient temperature affects Ts and SKBF which in turn influence the BIA measures of R and Xc, especially in the cold ambient temperature; the Guo BIA equation consistently underestimated FFM of young nonobese Chinese women in all temperatures; and the Lukaski equation closely approximates the FFM in the neutral and hot conditions compared with the FFM(UWW).

Adipose Tissue↗

PubMed2000

Molecular characterization of multidrug-resistant Streptococcus pneumoniae isolates in Korea. The Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study Group.

Pulsed-field gel electrophoresis, ribotyping, and fingerprinting analysis of 22 invasive isolates of multidrug-resistant (MDR) pneumococci from Korea showed that 59 to 82% were genetically related. DNA sequencing of the PBP 2B gene showed relatively uniform alterations in nucleotides (5.4 to 7.8%) and amino acids (3.0 to 4. 3%), while Asn-276-->Lys, Arg-285-->Cys and Ser-305-->Phe substitutions were unique to Korean MDR strains, suggesting the spread of a few epidemic clones of resistant pneumococci within Korea.

Anti-Bacterial Agents↗

PubMed2000

Korean Nationwide Surveillance of Antimicrobial Resistance of Bacteria in 1998.

Antimicrobial resistance surveillance can provide information needed for empirical therapy of antimicrobial agents and for control of resistance. To determine the trend of antimicrobial resistance in Korea, in vitro susceptibility data in 1998 were collected from 25 hospitals participating to a program of Korean Nationwide Surveillance of Antimicrobial Resistance (KONSAR). The data were analyzed based upon hospital location and bed capacity. The results showed that cefoxitin-resistant E. coli and K. pneumoniae and 3rd-generation cephalosporin-resistant K. pneumoniae were prevalent, that 3rd-generation cephalosporin-resistant E. cloacae, S. marcesens and A. baumannii had increased, and ampicillin-resistant S. enterica were not rare. Oxacillin-resistant S. aureus, penicillin-non-susceptible pneumococci and beta-lactamase-producing H. influenzae were prevalent even smaller hospitals surveyed, and an increase of imipenem-resistant P. aeruginosa and vancomycin-resistant E. faecium is a new obvious threat. In general, resistance rates to some old antimicrobial agents, i.e., E. coli to ampicillin and S. aureus to oxacillin were high and did not vary greatly between the different levels of hospitals, while the rates to some of the newer ones, i.e., P. aeruginosa to imipenem, was quite variable and depended on the hospitals, probably reflecting difference in selective pressure.

Ampicillin↗

PubMed2000

Biological deodorization of hydrogen sulfide using porous lava as a carrier of Thiobacillus thiooxidans.

Biological deodorization of hydrogen sulfide (H2S) was studied using porous lava as a carrier of Thiobacillus thiooxidans in a laboratory-scale biofilter. Three different samples of porous lava, A, B, and C, which were obtained from Cheju Island in Korea, were used. The water-holding capacities of samples A, B and C were 0.38, 0.25, and 0.47 g-H2O/g-lava, respectively. The pHs and densities of the lava samples ranged from 8.25-9.24 and 920-1190 kg/m3, respectively. The buffering capacities, expressed as the amount of sulfate added to lower the pH to 4, were 60 g-SO4(2-)/kg-lava for sample A, 50 g-SO4(2-)/kg-lava for B, and 90 g-SO4(2-)/kg-lava for C. To investigate the removal characteristics of H2S by the lava biofilters, T. thiooxidans was immobilized on the lava samples. Biofilters A and C showed a removal capacity of 428 g-S.m(-3).h(-1) when H2S was supplied with 428 g-S.m(-3).h(-1) of inlet load at a space velocity (SV) of 300 h(-1). At the same inlet load and SV, the removal capacity of biofilter B was 396 g-S.m(-3).h(-1). The H2S critical loads of biofilters A, B and C at a SV of 400 h(-1) were 396, 157 and 342 g-S.m(-3).h(-1), respectively. It is suggested that natural, porous lava is a promising candidate as a carrier of microorganisms in biofiltration.

Journal Article↗