Biomedical subjects

Eun-A Kim

Publications and source records attributed to Eun-A Kim.

11 recordsLinked to original sources

PubMed2006

Compact soft x-ray transmission microscopy with sub-50 nm spatial resolution.

In this paper, the development of compact transmission soft x-ray microscopy (XM) with sub-50 nm spatial resolution for biomedical applications is described. The compact transmission soft x-ray microscope operates at lambda = 2.88 nm (430 eV) and is based on a tabletop regenerative x-ray source in combination with a tandem ellipsoidal condenser mirror for sample illumination, an objective micro zone plate and a thinned back-illuminated charge coupled device to record an x-ray image. The new, compact x-ray microscope system requires the fabrication of proper x-ray optical devices in order to obtain high-quality images. For an application-oriented microscope, the alignment procedure is fully automated via computer control through a graphic user interface. In imaging studies using our compact XM system, a gold mesh image was obtained with 45 nm resolution at x580 magnification and 1 min exposure. Images of a biological sample (Coscinodiscus oculoides) were recorded.

Diatoms↗

PubMed2005

Phase II study of irinotecan plus cisplatin induction followed by concurrent twice-daily thoracic irradiation with etoposide plus cisplatin chemotherapy for limited-disease small-cell lung cancer.

PURPOSE: Irinotecan plus cisplatin (IP) chemotherapy demonstrated a promising outcome with a high complete response (CR) rate in chemotherapy-naïve patients with extensive small-cell lung cancer (SCLC). We evaluated the efficacy of induction IP chemotherapy followed by concurrent etoposide plus cisplatin (EP) chemotherapy with twice-daily thoracic radiotherapy (TDTRT) in limited-disease SCLC (LD-SCLC). PATIENTS AND METHODS: Between November 2001 and May 2003, 35 chemotherapy-naïve patients with LD-SCLC were enrolled. Thirty-three patients (94%) were male, and 29 (83%) had an Eastern Cooperative Oncology Group performance status of 0 or 1. The median age was 63 years. Treatment consisted of two 21-day cycles of cisplatin 40 mg/m2 and irinotecan 80 mg/m2 intravenously (i.v.) on days 1 and 8 followed by two 21-day cycles of cisplatin 60 mg/m2 i.v. on days 43 and 64, and etoposide 100 mg/m2 i.v. on days 43 to 45 and 64 to 66, with concurrent TDTRT of total 45 Gy beginning on day 43. RESULTS: All 35 patients were assessable for response. The objective response rate was 97% (CR, 3; partial response [PR], 31) after induction chemotherapy and 100% (CR, 15; PR, 20) after concurrent chemoradiotherapy (CCRT). After a median follow-up of 26.5 months, the median survival was 25.0 months (95% CI, 19.0 to 30.9) with 1- and 2-year overall survival rates of 85.7% and 53.9%, respectively. Median progression-free survival (PFS) was 12.9 months with a 1- and 2-year PFS of 58.5% and 36.1%, respectively. The most common toxicities were grade 3 or 4 neutropenia in 68% of patients during induction chemotherapy and 100% during CCRT. Febrile neutropenia occurred in 20% of patients during induction chemotherapy and 60% during CCRT. CONCLUSION: IP induction chemotherapy followed by concurrent TDTRT with EP chemotherapy showed a promising activity with favorable 1- and 2-year survival rates. Based on the favorable outcome in this trial, this regimen should be evaluated in a large phase III trial.

Adult↗

PubMed2005

Phosphorylation by the DHIPK2 protein kinase modulates the corepressor activity of Groucho.

Groucho function is essential for Drosophila development, acting as a corepressor for specific transcription factors that are downstream targets of various signaling pathways. Here we provide evidence that Groucho is phosphorylated by the DHIPK2 protein kinase. Phosphorylation modulates Groucho corepressor activity by attenuating its protein-protein interaction with a DNA-bound transcription factor. During eye development, DHIPK2 modifies Groucho activity, and eye phenotypes generated by overexpression of Groucho differ depending on its phosphorylation state. Moreover, analysis of nuclear extracts fractionated by column chromatography further shows that phospho-Groucho associates poorly with the corepressor complex, whereas the unphosphorylated form binds tightly. We propose that Groucho phosphorylation by DHIPK2 and its subsequent dissociation from the corepressor complex play a key role in relieving the transcriptional repression of target genes regulated by Groucho, thereby controlling cell fate determination during development.

Amino Acid Sequence↗

PubMed2005

A phase II study of dose-intensified weekly concomitant administration of cisplatin and irinotecan in chemonaive patients with extensive-disease small-cell lung cancer.

Irinotecan/cisplatin (IP) is an active regimen for extensive-disease small-cell lung cancer (ED-SCLC). However, the optimal dose/schedule is unsettled. To evaluate the efficacy and safety of a dose-intensified, weekly concomitant administration of IP, we conducted a phase II study in chemo-naive patients with ED-SCLC. Between October 2001 and February 2004, 37 patients were enrolled. Twenty-nine (78%) were male, 21 (57%) had ECOG PS 0 or 1, and the median age was 62 yr. The initial six patients received cisplatin 50 mg/m2 followed by irinotecan 90 mg/m2 iv on d 1 and 8 of a 21-d cycle (dose level I), with one treatment-related death, three febrile neutropenias. Thereafter, the doses of cisplatin and irinotecan were reduced to 40 mg/m2 and 80 mg/m2, respectively (dose level II). The treatment was continued for up to six cycles. The overall response rate was 97%, with a complete response (CR) rate of 26%. The median duration of response was 6.4 mo (range, 1.6-13.1 mo). At a median follow-up of 27.3 mo, the median survival time was 11.1 mo and 1- and 2-yr survival rates were 44.1% and 11.8%, respectively. The median progression-free survival (PFS) was 6.0 mo (range, 1.5-13.1 mo) and 1-year PFS rate was 7%. Major grade 3 or 4 toxicities included neutropenia (89%), anemia (59%), and diarrhea (27%). Despite of significant myelosuppresion, this dose-intensified weekly concomitant administration of cisplatin and irinotecan was feasible. This dose-schedule showed promising activity with high rate of complete remission in patients with ED-SCLC.

Adult↗

PubMed2004

Iron chelator triggers inflammatory signals in human intestinal epithelial cells: involvement of p38 and extracellular signal-regulated kinase signaling pathways.

Competition for cellular iron (Fe) is a vital component of the interaction between host and pathogen. Most bacteria have an obligate requirement for Fe to sustain infection, growth, and survival in host. To obtain iron required for growth, many bacteria secrete iron chelators (siderophores). This study was undertaken to test whether a bacterial siderophore, deferoxamine (DFO), could trigger inflammatory signals in human intestinal epithelial cells as a single stimulus. Incubation of human intestinal epithelial HT-29 cells with DFO increased the expression of IL-8 mRNA, as well as the release of IL-8 protein. The signal transduction study revealed that both p38 and extracellular signal-regulated kinase-1/2 were significantly activated in response to DFO. Accordingly, the selective inhibitors for both kinases, either alone or in combination, completely abolished DFO-induced IL-8 secretion, indicating an importance of mitogen-activated protein kinases pathway. These proinflammatory effects of DFO were, in large part, mediated by activation of Na(+)/H(+) exchangers, because selective blockade of Na(+)/H(+) exchangers prevented the DFO-induced IL-8 production. Interestingly, however, DFO neither induced NF-kappaB activation by itself nor affected IL-1beta- or TNF-alpha-mediated NF-kappaB activation, suggesting a NF-kappaB-independent mechanism in DFO-induced IL-8 production. Global gene expression profiling revealed that DFO significantly up-regulates inflammation-related genes including proinflammatory genes, and that many of those genes are down-modulated by the selective mitogen-activated protein kinase inhibitors. Collectively, these results demonstrate that, in addition to bacterial products or cell wall components, direct chelation of host Fe by infected bacteria may also contribute to the evocation of host inflammatory responses.

Deferoxamine↗

PubMed2004

Proteomic analysis of Acinetobacter lwoffii K24 by 2-D gel electrophoresis and electrospray ionization quadrupole-time of flight mass spectrometry.

The MS/MS analysis by Electrospray ionization quadrupole-time of flight mass spectrometry (ESI-Q-TOF MS) was applied to identify proteins in proteome analysis of bacteria whose genomes are not known. The protein identification by ESI-Q-TOF MS was performed sequentially by database search and then de novo sequencing using MS/MS spectra. Soil bacteria having unanalyzed genome, Acinetobacter lwoffii K24 is an aniline degrading bacterium. In this report, we present the results of a comparison between the proteome profile of A. lwoffii K24 cultured in aniline- or succinate-containing media. Protein analysis was performed using two-dimensional gel electrophoresis (2-DE) with pH 3-10 immobilized pH gradient (IPG) strips followed by ESI-Q-TOF MS. More than 780 protein spots were detected by 2-DE from the soluble proteome. Forty-eight of these proteins were expressed exclusively in aniline cultured bacteria, and 81 proteins increased and 162 proteins decreased in aniline-cultured versus succinate cultured A. lwoffii K24. Internal amino acid sequences of 43 major protein spots were successfully determined by ESI-Q-TOF MS to try to identify the bacterial proteins responding to aniline culture condition. Since the A. lwoffii K24 genome is not yet sequenced, many proteins were found to be hypothetical. Comparative proteome analysis of the insoluble protein fractions showed that one novel protein that was strongly induced by succinate-cultured A. lwoffii K24 was repressed under aniline culture conditions. These results suggest that comprehensive analysis of bacterial proteomes by 2-DE and amino acid sequence analysis by ESI-Q-TOF MS is useful for understanding induced novel proteins of biodegrading bacteria.

Acinetobacter↗

PubMed2004

Imaging findings of hepatic paragonimiasis : a case report.

Hepatic paragonimiasis is a rare form of ectopic infestation caused by Paragonimus. We experienced a case of hepatic paragonimiasis that showed characteristic imaging findings. CT and MR images showed a cluster of small cysts with rim enhancement in the subcapsular area of the liver. This finding seems to be characteristic for hepatic paragonimiasis, considering imaging findings in paragonimiasis involving other organs.

Adult↗

PubMed2003

A Phase II study of weekly irinotecan and capecitabine in patients with previously treated non-small cell lung cancer.

PURPOSE: Irinotecan and capecitabine have synergistic antitumor activity with distinct mechanisms of action but without overlapping major toxicity. We conducted a Phase II study to evaluate the efficacy of weekly irinotecan plus capecitabine in patients with previously treated non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Eligible patients had received at least one prior chemotherapy regimen. The treatment consisted of irinotecan (90-100 mg/m2 i.v.) on days 1 and 8 plus capecitabine (1000 mg/m2 p.o. b.i.d.) on days 1-14 of a 21-day cycle. Treatment was given until disease progression or unacceptable toxicity. RESULTS: Thirty-seven patients with median age of 59 years were enrolled. Eighteen (49%) patients had received one prior regimen, and 19 (51%) patients had received two or more prior regimens. The Initial 5 patients received 100 mg/m2 irinotecan with grade 3 diarrhea seen in 3 of 5 patients, and subsequent 32 patients received 90 mg/m2 irinotecan. Four (11.4%) of 35 evaluable patients had partial response and 12 (34.3%) had stable disease. There was no complete response. All responses were noted in patients who had received one prior regimen (4 of 18, 22%), but there was no response among the patients who had received two or more regimens. Median duration of response was 5.6 months (range, 5-8.7 months). At a median follow-up of 6 months, median survival was 7.4 months (95% confidence interval, 3.6-9.0). Grade 3 or 4 toxicities were neutropenia (12%), anemia (13%), and diarrhea (12%) at the dose level of 90 mg/m2. CONCLUSIONS: Weekly irinotecan plus capecitabine had favorable antitumor activity and toxicity profile as a second-line treatment for recurrent NSCLC. This regimen may provide an additional treatment option for patients with advanced NSCLC.

Adenocarcinoma↗

PubMed2002

Involvement of p38 MAP kinase during iron chelator-mediated apoptotic cell death.

Iron is an essential element for the neoplastic cell growth, and iron chelators have been tested for their potential anti-proliferative and cytotoxic effects. To determine the mechanism of cell death induced by iron chelators, we explored the pathways of the three structurally related mitogen-activated protein (MAP) kinase subfamilies during apoptosis induced by iron chelators. We report that the chelator deferoxamine (DFO) strongly activates both p38 MAP kinase and extracellular signal-regulated kinase (ERK) at an early stage of incubation, but slightly activates c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) at a late stage of incubation. Among three MAP kinase blockers used, however, the selective p38 MAP kinase inhibitor SB203580 could only protect HL-60 cells from chelator-induced cell death, indicating that p38 MAP kinase serves as a major mediator of apoptosis induced by iron chelator. DFO also caused release of cytochrome c from mitochondria and induced activation of caspase 3 and caspase 8. Interestingly, treatment of HL-60 cells with SB203580 greatly abolished cytochrome c release, and activation of caspase 3 and caspase 8. Collectively, the current study reveals that p38 MAP kinase plays an important role in iron chelator-mediated cell death of HL-60 cells by activating downstream apoptotic cascade that executes cell death pathway.

Animals↗

PubMed2002

Prognostic value of CT before thrombolytic therapy in iliofemoral deep venous thrombosis.

PURPOSE: To prospectively assess the computed tomographic (CT) findings of iliofemoral deep venous thrombosis (DVT) and evaluate their relevance to the treatment of DVT with catheter-directed thrombolysis. MATERIALS AND METHODS: Twenty-four consecutive patients with symptomatic iliofemoral DVT were studied with both nonenhanced and contrast-enhanced CT before thrombolytic therapy. Mean duration of clinical symptom was 15.8 days +/- 20.8 (range, 1-90 d). Selected CT findings were prospectively evaluated and correlated with duration of symptoms and outcome of thrombolytic therapy, including attenuation number of the thrombus on nonenhanced CT (in HU), presence of venous distention (distention ratio: vein diameter divided by the diameter of corresponding normal contralateral vein), and poor venous wall demarcation. The following threshold variables were also evaluated: attenuation > or =60 HU and distention ratio > or =1.5. RESULTS: CT was suggestive of DVT in all patients, although different patterns were present. Higher attenuation on noncontrast CT was seen in patients who had favorable outcome of thrombolytic therapy compared to poor responders (66.1 +/- 8.7 vs 45.9 +/- 9.6; P <.0001). Distention ratio was also significantly higher in the good response group (2.6 +/- 1.4 vs 1.4 +/- 0.7; P <.05). Recent onset of clinical symptoms was associated with better outcome (9.4 d +/- 8.9 vs 28.6 d +/- 31.2; P <.03). Multiple-stepwise regression analysis of these variable produce the results of "attenuation >60" as the most predictive variable of favorable outcome of thrombolysis, followed by "distention ratio >1.5" and poor demarcation. CONCLUSION: Selected CT findings are better predictors of a favorable outcome of thrombolytic therapy than duration of clinical symptoms alone.

Adult↗

PubMedDate not supplied

Focal hepatic lesions: contrast-enhancement patterns at pulse-inversion harmonic US using a microbubble contrast agent.

OBJECTIVE: To analyze the contrast-enhancement patterns obtained at pulse-inversion harmonic imaging (PIHI) of focal hepatic lesions, and to thus determine tumor vascularity and the acoustic emission effect. MATERIALS AND METHODS: We reviewed pulse-inversion images in 90 consecutive patients with focal hepatic lesions, namely hepatocellular carcinoma (HCC) (n=43), metastases (n=30), and hemangioma (n=17). Vascular and delayed phase images were obtained immediately and five minutes following the injection of a microbubble contrast agent. Tumoral vascularity at vascular phase imaging and the acoustic emission effect at delayed phase imaging were each classified as one of four patterns. RESULTS: Vascular phase images depicted internal vessels in 93% of HCCs, marginal vessels in 83% of metastases, and peripheral nodular enhancement in 71% of hemangiomas. Delayed phase images showed inhomogeneous enhancement in 86% of HCCs; hypoechoic, decreased enhancement in 93% of metastases; and hypoechoic and reversed echogenicity in 65% of hemangiomas. Vascular and delayed phase enhancement patterns were associated with a specificity of 91% or greater, and 92% or greater, respectively, and with positive predictive values of 71% or greater, and 85% or greater, respectively. CONCLUSION: Contrast-enhancement patterns depicting tumoral vascularity and the acoustic emission effect at PIHI can help differentiate focal hepatic lesions.

Adult↗