Biomedical subjects

Tae Hyun Kim

Publications and source records attributed to Tae Hyun Kim.

At least 19 recordsLinked to original sources

PubMed2006

zVAD-fmk, unlike BocD-fmk, does not inhibit caspase-6 acting on 14-3-3/Bad pathway in apoptosis of p815 mastocytoma cells.

In a preliminary study, we found that benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD- fmk), unlike Boc-aspartyl(OMe)-fluoromethylketone (BocD-fmk), at usual dosage could not prevent genistein-induced apoptosis of p815 mastocytoma cells. This study was undertaken to reveal the mechanism underlying the incapability of zVAD-fmk in preventing this type of apoptosis. We observed that 14-3-3 protein level was reduced in genistein-treated cells and that BocD-fmk but not zVAD-fmk prevented the reduction of 14-3-3 protein level and the release of Bad from 14-3-3. We also demonstrated that truncated Bad to Bcl-xL interaction in genistein- treated cells was prevented by BocD-fmk but not by zVAD-fmk treatment. Our data indicate that BocD- fmk, compared to zVAD-fmk, has a certain preference for inhibiting 14-3-3/Bad signalling pathway. We also elucidated that this differential efficacy of BocD-fmk and zVAD-fmk resulted from the different effect in inhibiting caspase-6 and that co-treatment of zVAD-fmk and caspase-6 specific inhibitor substantially prevented genistein-induced apoptosis. Our data shows that caspase-6 plays a role on Bad/14-3-3 pathway in genistein-induced apoptosis of p815 cells, and that the usual dose of zVAD-fmk, in contrast to BocD-fmk, did not prevent caspase-6 acting on 14-3-3/Bad-mediated event.

14-3-3 Proteins↗

PubMed2006

A purified extract from Clematis mandshurica prevents staurosporin-induced downregulation of 14-3-3 and subsequent apoptosis on rat chondrocytes.

OBJECTIVE: To dissect the mechanism of the protection of staurosporin-induced apoptosis on rat chondrocytes by a purified extract from Clematis mandshurica. DESIGN: Primary cultured rat articular chondrocytes as well as RCJ3.1C.18 cells were incubated with 1 microM staurosporin and 300 microg/ml purified extract from Clematis mandshurica. Western blot assay, silencing 14-3-3 gene and immunoprecipitation were conducted. RESULTS: Clematis mandshurica prevented staurosporin-induced downregulation of several antiapoptotic bcl-2 family proteins Bcl-xL and Bcl-2, and staurosporin-induced upregulation of an apoptotic bcl-2 family protein Bax. Clematis mandshurica also prevented staurosporin-induced downregulation of a premitochondrial antiapoptotic protein 14-3-3. It is noticeable that siRNA to 14-3-3 abolished the prevention of caspase-3 activation by Clematis mandshurica. Furthermore viability assay corroborated that silencing of 14-3-3 gene abolished this apoptosis protection efficacy by Clematis mandshurica. Immunoprecipitation assay elucidated that Clematis mandshurica prevented the staurosporin-induced reduction of the interactions between 14-3-3 with phospho-ser112-Bad and Bcl-xL to phospho-ser155-Bad. CONCLUSIONS: Clematis mandshurica prevents staurosporin-induced apoptosis of rat chondrocytes via 14-3-3.

14-3-3 Proteins↗

PubMed2006

Comparison of 5-fluorouracil/leucovorin and capecitabine in preoperative chemoradiotherapy for locally advanced rectal cancer.

PURPOSE: To describe our experience with a bolus injection of 5-fluorouracil and leucovorin (FL) vs. capecitabine in terms of radiologic and pathologic findings in preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer. METHODS: The study enrolled 278 patients scheduled for preoperative CRT using two protocols with different chemotherapeutic regimens. Pelvic radiotherapy (50.4 Gy) was delivered concurrently with FL (n = 145) or capecitabine (n = 133). Surgery was performed 6 weeks after CRT completion. Tumor responses to CRT were measured using both radiologic and pathologic examination. Magnetic resonance volumetry was performed at the initial workup and just before surgery after completion of preoperative CRT. Post-CRT pathology tests were used to determine tumor stage and regression. RESULTS: Radiologic examination showed that tumor volume decreased by 68.2% +/- 20.5% in the FL group and 68.3% +/- 22.3% in the capecitabine group (p = 0.970). Postoperative pathologic T stage determination showed that downstaging occurred in 44.3% of FL and 49.9% of capecitabine patients (p = 0.571). The tumor regression grades after CRT were Grade 1 (minimal response) in 22.6% and 21.0%, Grade 2 (moderate response) in 53.2% and 50.0%, Grade 3 (near-complete response) in 12.9% and 12.9%, and Grade 4 (complete response) in 11.3% and 16.1% of the FL and capecitabine groups, respectively (p = 0.758). CONCLUSION: In the present study, the radiologic and pathologic findings did not reveal significant differences in short-term tumor responses between preoperative FL and capecitabine CRT for locally advanced rectal cancer. Long-term results and a prospective randomized trial are needed.

Adult↗

PubMed2006

Structure-selective recognition by voltammetry: enantiomeric determination of amines using azophenolic crowns in aprotic solvent.

The enantiomeric recognition of amines by voltammetry using electroactive macrocyclic molecules, nitroazophenolic crown ethers, is reported. The oxidation potential of the nitroazophenol moiety in nitroazophenols with 18-crown-6 sensitively depends on the structure of alkyl amines. Based on this phenomenon, enantiomeric amines and even the quantitative assay of the R/S ratio in enantiomeric mixtures can be selectively recognized by using 18-crown-6 azophenol (3-H) with chiral centers. In the case of phenylglycinol, the association constants (K) of 3-H for the R and S forms have an R/S value of 3.5. The peak potential of the R form in square-wave voltammograms reproducibly differs from that of the S form by 32 mV, within which the peak potential linearly varies with the enantiomeric ratio. Free energy perturbation and molecular dynamics simulation provide deeper understanding of the enantiomeric recognition in this system. The theoretical analysis indicates that the free energy difference between diastereomeric complexes agrees well with the experimental results, and the pi-pi or charge-charge interaction plays a key role in enantiomeric recognition.

Amines↗

PubMed2006

Dose-volumetric parameters predicting radiation-induced hepatic toxicity in unresectable hepatocellular carcinoma patients treated with three-dimensional conformal radiotherapy.

PURPOSE: To identify the dose-volumetric parameters associated with the risk of radiation-induced hepatic toxicity (RIHT) in hepatocellular carcinoma patients treated with three-dimensional conformal radiotherapy. METHODS AND MATERIALS: A total of 105 hepatocellular carcinoma patients underwent three-dimensional conformal radiotherapy (total dose range, 44-58.5 Gy; median, 54). RIHT was scored within 4 months of completing three-dimensional conformal radiotherapy. The dose-volume parameters analyzed were the gross tumor volume; normal liver volume; total liver volume; radiation dose; mean dose to the normal liver; percentage of the normal liver volume receiving > or =20, > or =25, > or =30, > or =35, and > or =40 Gy; percentage of the total liver volume receiving > or =20, > or =25, > or =30, > or =35, and > or =40 Gy; and the normal tissue complication probability. RESULTS: Of the 105 patients, Grade 1 RIHT was observed in 21 (20.0%), Grade 2 in 7 (6.7%), Grade 3 in 5 (4.8%), and Grade 4 in 1 (1.0%) patient. No fatal Grade 5 RIHT developed. On multivariate analysis for predicting Grade 2 or worse RIHT, the total liver volume receiving > or =30 Gy was the only significant parameter (p < 0.001). Grade 2 or worse RIHT was observed in only 2 (2.4%) of 85 patients with a total liver volume receiving 30 Gy of < or =60% and in 11 (55.0%) of 20 patients with >60% (p < 0.001). CONCLUSION: The total liver volume receiving > or =30 Gy appears to be a useful dose-volumetric parameter for predicting the risk of RIHT. This volume should be limited to < or =60% whenever possible to minimize the risk of Grade 2 or worse RIHT.

Adult↗

PubMed2006

Expression of rice acyl-CoA oxidase isoenzymes in response to wounding.

To elucidate the role of acyl-CoA oxidase (ACX; EC 1.3.3.6) in plants, the expression patterns of rice ACXs in response to wounding were characterized. Three isogenes of ACX were identified in the rice genome. The deduced proteins of OsACX1, OsACX2 and OsACX3 consist of 669, 699 and 685 amino acid residues, respectively. The results from reverse transcriptase-PCR indicate that OsACX1 is expressed in leaves, stems, and roots, but was barely detectable in germinating seeds. OsACX2 was expressed predominantly in seeds. Only OsACX1 was upregulated by wounding, both locally and systemically. The expression of OsACX2 and OsACX3 remained unchanged. It is suggested that OsACX2 is involved in providing germinating seeds with sugar and energy, while OsACX1 plays a role in the synthesis of jasmonic acid in response to wounding.

Acetates↗

PubMed2006

Intensity-modulated radiotherapy with a belly board for rectal cancer.

BACKGROUND AND AIM: Intensity-modulated radiotherapy (IMRT) techniques can reduce the irradiated small bowel volume in rectal cancer patients, but combined use of IMRT and a belly board is yet to be reported on for rectal cancer patients. The aim of this study was to determine whether additional use of a belly board reduced the irradiated small bowel volume observed using IMRT alone in rectal cancer patients. MATERIALS AND METHODS: Twenty patients scheduled to receive preoperative radiotherapy for rectal cancer underwent two series of CT scans, with and without a belly board. IMRT planning was performed using 6-MV photon beams and seven equispaced fields. The bladder, small bowel, and planning target volume (PTV) were analyzed for doses between 10% and 100% of the prescribed dose at 10% intervals. Data were analyzed using Wilcoxon signed rank tests. RESULTS: There were no significant differences between patients undergoing IMRT with a belly board and those without a belly board in terms of total small bowel volumes, bladder, and PTV (p=0.571, p=0.841, and p=0.870, respectively). Statistical analysis showed that the irradiated small bowel volume with a belly board was smaller than that without a belly board (p<0.05 at 20-100% dose levels), with the mean relative reduction in the irradiated small bowel volume being 37.8+/-32.8%. CONCLUSION: IMRT with a belly board is more effective than IMRT alone in reducing the irradiated small bowel volume. These findings suggest that the use of a belly board with IMRT may reduce small bowel complications in preoperative radiotherapy.

Adult↗

PubMed2006

Geometric shifting of the porta hepatis during posthepatectomy radiotherapy for biliary tract cancer.

PURPOSE: To evaluate geometric shifting of the porta hepatis induced by liver regeneration during radiotherapy (RT) after partial hepatectomy for biliary tract cancer. METHODS AND MATERIALS: Between August 2004 and August 2005, the study enrolled 10 biliary tract cancer patients who underwent hemihepatectomy or more extensive surgery and were scheduled to receive postoperative RT. All patients received 4500 cGy RT in 25 fractions with concurrent 5-fluorouracil. Before RT and in the third and fifth weeks during RT, the liver volume was determined using CT, and geometric location of the porta hepatis was determined using a conventional simulator. RESULTS: The liver volume increase during RT was 246.6 +/- 118.2 cm(3). The overall actual shifting length of the porta hepatis was 9.8 +/- 2.5 mm, with right and left hepatectomy causing a 10.1 +/- 1.7 mm shift to the right or 9.2 +/- 4.3 mm shift to the left, respectively. The actual shifting length of the porta hepatis was proportional to the increase in liver volume during RT (r = 0.742, p = 0.014). CONCLUSION: The results of this study have demonstrated that the porta hepatis can be shifted by liver regeneration after partial hepatectomy. We recommend an additional RT margin or adaptive RT (repeat planning at several intervals during the treatment course) to avoid exclusion of the porta hepatis from the RT target volume after partial hepatectomy for biliary tract cancer.

Adenocarcinoma↗

PubMed2006

Is T classification still correlated with lymph node status after preoperative chemoradiotherapy for rectal cancer?

BACKGROUND: It is well known that the risk of lymph node involvement increases according to pathologic T classification in rectal cancers, but to the authors' knowledge, the correlation between risk of lymph node involvement and ypT classification in rectal cancers treated with preoperative chemoradiotherapy (CRT) remains unclear. The current study investigated the correlation between tumor involvement in regional lymph nodes and rectal mural tumor status in patients who underwent preoperative CRT for rectal cancer. METHODS: Between October 2001 and February 2005, 282 patients underwent preoperative CRT followed by proctectomy for locally advanced rectal adenocarcinoma. Correlations between lymph node status and ypT classification, Dworak regression grade, and magnetic resonance (MR) volumetry findings were explored. RESULTS: Lymph nodes harboring tumors were found in 87 of 282 (30.9%) patients. The rate of lymph node involvement was found to be correlated with ypT-classification (P < .001); positive lymph nodes were detected in 1 of 45 (2.2%) ypT0 patients, 1 of 13 (7.7%) ypT1 patients, 13 of 77 (16.9%) ypT2 patients, 69 of 140 (49.3%) ypT3 patients, and 3 of 7 (42.9%) ypT4 patients. The rate of lymph node involvement decreased as Dworak regression grade increased (P < .001); tumor-harboring lymph nodes were found in 62.3% of Grade 1 patients, 31.4% of Grade 2 patients, 16.1% of Grade 3 patients, and 2.2% of Grade 4 patients. There were no differences noted with regard to MR volumetry findings, including mean volume of pre- or post-CRT tumor and the tumor volume reduction rate between lymph node-negative and lymph node-positive patients. CONCLUSIONS: Pathologic T classification is still the most reliable predictor of lymph node metastasis in rectal cancer patients who have undergone preoperative CRT. The risk of lymph node metastasis was found to be 3.4% in rectal cancer that had regressed to ypT0 or ypT1.

Adenocarcinoma↗

PubMed2006

Clinical impact of FDG-PET imaging in post-therapy surveillance of uterine cervical cancer: from diagnosis to prognosis.

OBJECTIVES: To evaluate the ability of whole-body 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scan to detect recurrent cervical cancer in women during follow-up after definitive treatment. METHODS: We retrospectively reviewed the whole-body FDG-PET scan of the women who had reached complete response after primary treatment for detection of recurrent cervical cancer between September 1, 2001 and October 31, 2004. RESULTS: One hundred twenty-one consecutive patients were registered for the current study and seventy-six women were diagnosed as recurrence, twenty of which were asymptomatic. The FDG-PET scan detected 73 (96.1%) patients among 76 patients with recurrent disease and discriminated 38 (84.4%) patients among 45 patients without recurrence. The sensitivity, specificity and accuracy of the FDG-PET scan in assessment of recurrence among patients with cervical cancer were 96.1%, 84.4% and 91.7% respectively. Sixteen patients with no evidence of distant metastasis on FDG-PET scan received pelvic exenteration; complete response was achieved in 6 (37.5%) patients, and all are alive with no evidence of disease. The FDG-PET scan detected FDG-avid lesions in 17 (85.0%) of the 20 asymptomatic patients with recurrent disease, and 8 (40.0%) patients received therapy with curative intent; complete response was achieved in five (25.0%) patients and all are alive with no evidence of disease. Three-year overall survival of this study was 85.6%. CONCLUSIONS: The whole-body FDG-PET scan is a sensitive post-therapy surveillance modality for detection of recurrent cervical cancer even in asymptomatic patients and aids in deciding treatment plans and, eventually, may have favorable impact on prognosis and survival.

Adult↗

PubMed2006

Preoperative chemoradiotherapy with concomitant small field boost irradiation for locally advanced rectal cancer: a multi-institutional phase II study (KROG 04-01).

PURPOSE: This study was designed to determine the effect of concomitant small field boost irradiation given during preoperative chemoradiotherapy for patients with locally advanced rectal cancer. METHODS: The study prospectively enrolled 38 patients scheduled for preoperative chemoradiotherapy. Pelvic radiotherapy of 43.2 Gy/24 fractions was delivered and boost radiotherapy of 7.2 Gy/12 fractions was concomitantly administered during the latter half of the pelvic radiotherapy treatment period. Two cycles of a bolus 5-fluorouracil and leucovorin injection in the first and fifth weeks of radiotherapy were administered. The median time to surgery after completion of chemoradiotherapy was six weeks. Tumor responses to chemoradiotherapy were assessed by using magnetic resonance volumetry and post-chemoradiotherapy pathology tests to determine tumor downstaging and tumor regression rate. RESULTS: Thirty-six of 38 patients (94.7 percent) underwent the scheduled surgery. The mean tumor volume reduction rate was 70.3 percent, and the clinical response rate was 66.7 percent. The downstaging rates were 41.7 percent for T classification, 85.2 percent for N classification, and 72.2 percent for stage. Tumor regression grades after preoperative chemoradiotherapy were Grade 1 in 5 patients (13.9 percent), Grade 2 in 24 patients (66.7 percent), Grade 3 in 3 patients (8.3 percent), and Grade 4 in 4 patients (11.1 percent). Ten patients (26.3 percent) experienced > or = Grade 3 acute toxicity. CONCLUSIONS: Our data suggest that concomitant boost irradiation does not improve clinical outcomes compared with other published preoperative chemoradiotherapy regimens. In addition, the clinicians choosing to use concomitant small field boost irradiation should be cautious to minimize the risk of unplanned sphincter ablation.

Adult↗

PubMed2006

The effect of belly board location in rectal cancer patients treated with preoperative radiotherapy.

AIMS: To evaluate the effect of the belly board aperture location on the irradiated small bowel volume in rectal cancer patients treated with preoperative pelvic radiotherapy. MATERIALS AND METHODS: Twenty patients with rectal cancer scheduled to receive preoperative pelvic radiotherapy were evaluated prospectively. Each patient underwent computed tomography with the belly board aperture lower border at three different locations relative to patient anatomy: the lumbosacral junction (location I), the lower end of the sacroiliac joint (location II) and the upper end of the symphysis pubis (location III). The irradiated small bowel volume was calculated for doses between 10 and 100% of the prescribed dose at 10% intervals. For each 10% dose increment, the effect of the belly board aperture at the three different locations on the irradiated small bowel volume was analysed using Wilcoxon signed rank and Wilcoxon rank sum tests. RESULTS: At 10-20% dose levels, the irradiated small bowel volume increased in the order of locations I, II and III, and the differences between each location were significant. At > or = 30% dose levels, the irradiated small bowel volume increased in the order of locations III, II and I, and the differences between locations I and II were significant, but the differences between locations II and III were not significant. CONCLUSION: The belly board aperture location can influence the irradiated small bowel volume differently at each dose level. When considering the use of a belly board in routine clinical practice, we recommend that the clinician take into account the patterns of irradiated small bowel volume according to belly board aperture location.

Adult↗

PubMed2006

Three-dimensional conformal radiotherapy of unresectable hepatocellular carcinoma patients for whom transcatheter arterial chemoembolization was ineffective or unsuitable.

OBJECTIVES: To evaluate 3-dimensional conformal radiotherapy (3D-CRT) of unresectable hepatocellular carcinoma (HCC) patients for whom transcatheter arterial chemoembolization (TACE) was ineffective or unsuitable, and to determine whether tumor response and portal vein thrombosis (PVT) response to treatment were prognostic factors for overall survival. METHODS: From July 2001 to June 2005, 70 unresectable HCC patients were treated with 3D-CRT; PVT was present in 41 patients. A daily radiation dose ranging from 2 to 3 Gy was administered using 6 or 15 MV x-rays to deliver a total dose between 44 and 54 Gy. RESULTS: Of 70 patients, follow-up computed tomography showed that primary tumor responses were complete response (CR) in 4 (5.7%) patients, partial response (PR) in 34 (48.6%), no response (NR) in 28 (37.1%), and progressive disease (PD) in 4 (8.6%). Of 41 patients with PVT, PVT responses were CR in 4 (9.7%) patients, PR in 12 (29.3%), NR in 20 (48.8%), and PD in 5 (12.2%). The median survival times were 18.0 and 20.1 month in the primary tumor and the PVT responders (CR + PR), respectively, which were longer than the 6.8 and 7.2 months in the primary tumor and the PVT nonresponders (NR + PD), respectively. CONCLUSIONS: 3D-CRT was associated with a 54.3% objective response rate for primary tumors and a 39.0% objective response rate for PVT. Both primary tumor and PVT responses were found to be prognostic factors for overall survival. The present results suggest 3D-CRT is a practical treatment option in HCC patients for whom TACE is ineffective or unsuitable.

Adult↗

PubMed2006

Amniotic membrane corrects surgically induced astigmatism.

Human amniotic membrane (AM) has been widely used for the reconstruction of ocular surface. We conducted this study to investigate whether AM shows efficacy in maintaining the correction of astigmatism or not. We performed photoastigmatic refractive keratectomy (PARK) on rabbits and grafted AM on the cornea. The effect of AM on the degree of astigmatism was evaluated by topography and cycloplegic refraction. As will be shown, AM did not show any efficacy in maintaining the correction of astigmatism. On the contrary, AM not only eliminated PARK-induced astigmatism but prevented surgically induced astigmatism. We suggest that AM could be a useful tool for controlling the astigmatism induced by laser refractive surgery. Further clinical study is still left to be elucidated.

Amnion↗

PubMed2006

Enzymatic production of xylooligosaccharides from corn stover and corn cobs treated with aqueous ammonia.

A novel method of producing food-grade xylooligosaccharides from corn stover and corn cobs was investigated. The process starts with pretreatment of feedstock in aqueous ammonia, which results delignified and xylan-rich substrate. The pretreated substrates are subjected to enzymatic hydrolysis of xylan using endoxylanase for production of xylooligosaccharides. The conventional enzyme-based method involves extraction of xylan with a strong alkaline solution to form a liquid intermediate containing soluble xylan. This intermediate is heavily contaminated with various extraneous components. A costly purification step is therefore required before enzymatic hydrolysis. In the present method, xylan is obtained in solid form after pretreatment. Water-washing is all that is required for enzymatic hydrolysis of this material. The complex step of purifying soluble xylan from contaminant is essentially eliminated. Refining of xylooligosaccharides to food-grade is accomplished by charcoal adsorption followed by ethanol elution. Xylanlytic hydrolysis of the pretreated corn stover yielded glucan-rich residue that is easily digestible by cellulase enzyme. The digestibility of the residue reached 86% with enzyme loading of 10 filter paper units/g-glucan. As a feedstock for xylooligosaccharides production, corn cobs are superior to corn stover because of high xylan content and high packing density. The high packing density of corn cobs reduces water input and eventually raises the product concentration.

Ammonia↗

PubMed2006

Pretreatment of corn stover by low-liquid ammonia recycle percolation process.

A pretreatment method using aqueous ammonia was investigated with the intent of minimizing the liquid throughput. This process uses a flowthrough packed column reactor (or percolation reactor). In comparison to the ammonia recycle percolation (ARP) process developed previously in our laboratory, this process significantly reduces the liquid throughput to one reactor void volume in packed bed (2.0-4.7 mL of liquid/g of corn stover) and, thus, is termed low-liquid ARP (LLARP). In addition to attaining short residence time and reduced energy input, this process achieves 59-70% of lignin removal and 48-57% of xylan retention. With optimum operation of the LLARP to corn stover, enzymatic digestibilities of 95, 90, and 86% were achieved with 60, 15, and 7.5 filter paper units/g of glucan, respectively. In the simultaneous saccharification and fermentation test of the LLARP samples using Saccharomyces cerevisiae (NREL-D5A), an ethanol yield of 84% of the theoretical maximum was achieved with 6% (w/v) glucan loading. In the simultaneous saccharification and cofermentation (SSCF) test using recombinant Escherichia coli (KO11), both the glucan and xylan in the solid were effectively utilized, giving an overall ethanol yield of 109% of the theoretical maximum based on glucan, a clear indication that the xylan content was converted into ethanol. The xylooligomers existing in the LLARP effluent were not effectively hydrolyzed by cellulase enzyme, achieving only 60% of digestibility. SSCF of the treated corn stover was severely hampered when the substrate was supplemented with the LLARP effluent, giving only 56% the overall yield of ethanol. The effluent appears to significantly inhibit cellulase and microbial activities.

Ammonia↗

PubMed2005

Application of newly developed amniotic membrane ointment for photorefractive keratectomy in rabbits.

We developed amniotic membrane ointment (AMO), and the effect of instilling the AMO after photorefractive keratectomy (PRK) was investigated with respect to inflammatory cell infiltration into the corneal stroma, apoptosis of keratocytes, and suppression of lipid peroxidation of cellular walls. The PRK procedure was performed on both eyes of 10 white rabbits. One eye of each rabbit (the experimental eye) was instilled with the AMO and the other eye of the rabbit (the control eye) with a base ointment 0, 8 and 16 h after the PRK procedure. Corneal specimens were collected 24 h after the PRK procedure. Hematoxylin-eosin stain and TUNEL assay were conducted to demonstrate polymorphonuclear and apoptotic cells, respectively. To assess lipid peroxidation, immunohistochemical staining with an antibody to malondialdehyde was undertaken. Compared to the control, the cornea instilled with the AMO had significantly less polymorphonuclear cells infiltrating into the corneal stroma as well as keratocytes subjected to apoptosis. These corneas also showed a significantly less extent of lipid peroxidation than the control. These data support that instillation of the AMO effectively reduced the recruitment of polymorphonuclear cells, the induction of apoptosis in keratocytes, and lipid peroxidation induced by PRK. Thus, this study could provide basic data on the clinical application of the AMO in the days ahead.

Amnion↗

PubMed2005

CT-guided intracavitary radiotherapy for cervical cancer: Comparison of conventional point A plan with clinical target volume-based three-dimensional plan using dose-volume parameters.

PURPOSE: To perform an intracavitary radiotherapy (ICR) plan comparison between the conventional point A plan (conventional plan) and computed tomography (CT)-guided clinical target volume-based plan (CTV plan) by analysis of the quantitative dose-volume parameters and irradiated volumes of organs at risk in patients with cervical cancer. METHODS AND MATERIALS: Thirty plans for 192Ir high-dose-rate ICR after 30-40-Gy external beam radiotherapy were investigated. CT images were acquired at the first ICR session with artifact-free applicators in place. The gross tumor volume, clinical target volume (CTV), point A, and International Commission on Radiation Units and Measurements Report 38 rectal and bladder points were defined on reconstructed CT images. A fractional 100% dose was prescribed to point A in the conventional plan and to the outermost point to cover all CTVs in the CTV plan. The reference volume receiving 100% of the prescribed dose (V(ref)), and the dose-volume parameters of the coverage index, conformal index, and external volume index were calculated from the dose-volume histogram. The bladder, rectal point doses, and percentage of volumes receiving 50%, 80%, and 100% of the prescribed dose were also analyzed. RESULTS: Conventional plans were performed, and patients were categorized on the basis of whether the 100% isodose line of point A prescription dose fully encompassed the CTV (Group 1, n = 20) or not (Group 2, n = 10). The mean gross tumor volume (11.6 cm3) and CTV (24.9 cm3) of Group 1 were smaller than the corresponding values (23.7 and 44.7 cm3, respectively) for Group 2 (p = 0.003). The mean V(ref) for all patients was 129.6 cm(3) for the conventional plan and 97.0 cm3 for the CTV plan (p = 0.003). The mean V(ref) in Group 1 decreased markedly with the CTV plan (p < 0.001). For the conventional and CTV plans in all patients, the mean coverage index, conformal index, and external volume index were 0.98 and 1.0, 0.23 and 0.34, and 3.86 and 2.15, respectively. Statistical analysis showed that the conformal index and external volume index improved significantly with the CTV plan, and this improvement was more marked in Group 1. The mean values of the bladder and rectal point doses and volume fractions receiving 50%, 80%, and 100% of the reference dose did not differ between plans for all patients. The reduction in the mean rectal and bladder point doses and irradiated volumes for the CTV plan was statistically significant in Group 1. CONCLUSION: Computed tomography-guided CTV planning of ICR is superior to conventional point A planning in terms of conformity of target coverage and avoidance of overdosed normal tissue volume. To ascertain the potential benefit of treatment outcome, ICR with image-guided three-dimensional plans will be pursued and correlated with the dose-volume parameters.

Antineoplastic Agents↗