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Biomedical subjects

K Park

Publications and source records attributed to K Park.

At least 19 recordsLinked to original sources
PubMed2006

Three-week schedule of irinotecan plus cisplatin in patients with previously untreated extensive-stage small-cell lung cancer.

Irinotecan and cisplatin demonstrated promising outcomes in extensive-stage small-cell lung cancer. According to the dosage and schedule of irinotecan, efficacy and toxicity profiles showed subtle differences. This study was designed to evaluate efficacy and toxicity of 3-week schedule of irinotecan/cisplatin in patients with previously untreated extensive-stage small-cell lung cancer. The primary objective was to evaluate response rate and secondary objectives were overall survival and progression-free survival. Patients with previously untreated extensive-stage small-cell lung cancer were enrolled. Irinotecan 65 mg m-2 was administered on days 1 and 8 and cisplatin 60 mg m-2 on day 1. Treatment was repeated every 3 weeks. Seven out of 54 patients (13.0%) had complete response, and partial response was observed in 33 (61.1%). The overall response rate was 74.1% (95% CI; 62.0-82.2%). Stable disease was observed in eight (14.8%) and no progressive disease was observed. After a median follow-up duration of 28.7 months, the median overall survival and progressive-free survival were 13.6 and 6.5 months, respectively. Major grade 3/4 toxicities were neutropenia (50.0%), anorexia (42.6%), diarrhoea (29.6%), fatigue (29.6%) and vomiting (13.0%). There was one treatment-related death owing to pneumonia. Three-week schedule of irinotecan/cisplatin showed effective antitumour activity and moderate toxicities in patients with previously untreated extensive-stage small-cell lung cancer.

Aged↗
PubMed2006

Frequency and prognosis of delayed facial palsy after microvascular decompression for hemifacial spasm.

BACKGROUND: Microvascular decompression (MVD) for hemifacial spasm (HFS) provides a long-term cure rate. Delayed facial palsy (DFP) is not an unusual complication, but it has only been sporadically described in the literature. The purpose of this report is to evaluate the incidence of delayed facial palsy after MVD and its clinical course and final results. METHODS: From January, 1998 to April, 2004, 410 patients underwent microvascular decompression for hemifacial spasm at our Institute. During this time, 21 patients (5.4%) developed delayed facial weakness; eighteen of them were given steroid medication and they were followed up in the out-patient clinic. FINDINGS: Twenty-one patients developed DFP after microvascular decompression an incidence of 5.4%. There were seventeen women (81.0%) among the 21 patients with DFP who were included in this study. In twenty of them, the symptoms of HFS improved completely after the operation, but the spasm remained with one of them. The onset of palsy occurred between postoperative day 7 and 23 (average: 12.1 days). The palsy was at least Grade II or worse on the House-Brackmann (HB) scale. The time to recovery averaged 5.7 weeks (range: 25 days-17 weeks); 20 patients improved to complete recovery and 1 patient remained with minimal weakness, as Grade II on the HB scale, at the follow-up examination. CONCLUSION: Our findings demonstrated that the incidence of DFP was not so low as has been reported the literature, and it did not have any striking predisposing factors. Even though the degree of facial palsy was variable, almost all patients exhibited a complete recovery without any further special treatment. The etiology of DFP and its association with herpes infection should be further clarified.

Adult↗
PubMed2006

Cox-2 expression on tissue microarray of breast cancer.

AIM: To measure cyclooxygenase-2 (Cox-2) expression in a series of breast cancers and evaluate its potential as a predictive marker for doxorubicin chemotherapy. PATIENTS AND METHODS: Cox-2 expression was analyzed in 178 node-positive patients treated with doxorubicin-based adjuvant chemotherapy by immunohistochemistry on tissue microarray (TMA). RESULTS: Cox-2 was over-expressed in 70 out of the 178 invasive breast cancers. Cox-2 expression was significantly increased in undifferentiated tumors. There was no significant association between Cox-2 over-expression and tumor size, histologic grade, and estrogen receptor expression. Disease-free survival and overall survival of the patients having Cox-2 expressing tumor were significantly decreased when compared with the patients having Cox-2 negative tumor (p=0.009 for DFS, p=0.011 for OS). CONCLUSION: Cox-2 expression may represent an aggressive phenotype of breast cancer which is resistant to doxorubicin.

Antibiotics, Antineoplastic↗
PubMed2006

Comparison of an aprepitant regimen with a multiple-day ondansetron regimen, both with dexamethasone, for antiemetic efficacy in high-dose cisplatin treatment.

BACKGROUND: We compared an aprepitant regimen with a control regimen of ondansetron + dexamethasone given for 4 days. PATIENTS AND METHODS: Patients scheduled to receive cisplatin > or =70 mg/m(2) were randomized to either the aprepitant regimen (aprepitant, ondansetron and dexamethasone on day 1; aprepitant and dexamethasone on days 2-3; dexamethasone on day 4) or control regimen (ondansetron + dexamethasone on days 1-4). Patients recorded vomiting, nausea and rescue therapy use. The primary end point was complete response (no vomiting and no use of rescue therapy) in the overall phase (days 1-5 post-cisplatin). RESULTS: Complete response rates were higher in the aprepitant than control group in the overall (72% versus 61%; P = 0.003), acute (day 1; 88% versus 79%; P = 0.005) and delayed phases (days 2-5; 74% versus 63%; P = 0.004), as were rates of no vomiting (overall 77% versus 62%, P < or = 0.001; acute 89% versus 81%, P = 0.004; delayed 79% versus 64%, P < or = 0.001). Rates of no rescue therapy were similar between groups. CONCLUSIONS: Compared with an antiemetic regimen in which ondansetron + dexamethasone were given for 4 days, the aprepitant regimen was superior in the acute, delayed and overall phases of chemotherapy-induced nausea and vomiting. The aprepitant regimen should be considered a new standard of antiemetic therapy for cisplatin-treated patients. www.ClinicalTrials.gov Identifier: NTC00090207.

Adult↗
PubMed2006

Rare cases of Ménière's disease in children.

Classical Ménière's disease is rarely found in children and literature regarding it is scarce. In general, the frequency of Ménière's disease in children is only 0.4-7.0 per cent of that in adults. The progression pattern of Ménière's disease in children is not known well. Here, we report three cases of Ménière's disease in children less than 15 years old, treated over nine years. The three cases comprise 14- and 13-year-old boys and a nine-year-old girl. Two of the three patients initially complained only of recurrent bouts of vertigo, without any tinnitus, ear fullness or hearing impairment. In all three cases, the early pure tone audiograms showed only high tone frequency loss, regardless of subjective hearing loss, and the decrease in the hearing threshold was observed one to eight years after the dizziness attacks began. The hearing threshold was usually decreased to a level of mild or moderate hearing impairment. After diuretic treatment, vertigo was generally well controlled, and some cases showed improvement in hearing. Of the total number of patients with Ménière's disease who visited our department over nine years, 2.6 per cent (3/114) were children, and the overall incidence of Ménière's disease in children with vertigo was 2.0 per cent (3/147). In conclusion, Ménière's disease in children rarely develops and may have characteristics of high tone loss in initial audiograms.

Adolescent↗
PubMed2006

High-dose chemotherapy with autologous stem cell transplantation in extranodal NK/T-cell lymphoma: a retrospective comparison with non-transplantation cases.

To determine the role of high-dose chemotherapy and autologous stem cell transplantation (HDC/ASCT) in extranodal NK/T-cell lymphoma patients, we conducted a retrospective analysis. In our previous study, we searched for patients who had received HDC/ASCT and identified 16 eligible patients and compared the treatment outcome with historical control group (n=246). Nine patients received HDC/ASCT in the first (CR1) or second complete remission (CR2), while seven patients received HDC/ASCT as salvage. Twelve of 16 patients achieved or maintained CR after HDC/ASCT. Among the 12 patients, five patients relapsed. Estimated 2-year overall survival (OS) and relapse-free survival (RFS) rates were 71.3+/-12.4% and 25.8+/-14.3%, respectively. There was a tendency of better survival in patients who received HDC/ASCT as compared to those who did not (P=0.091). In subset analysis, patients who underwent HDC/ASCT at CR (P=0.049) and patients with stage III or IV (P=0.001) had a favorable outcome. Patients with NKIPI 3,4 or EUNKTL, who underwent HDC/ASCT had more prolonged survival without statistical significance (P=0.055 and 0.056). In conclusion, HDC/ASCT may be considered as a treatment option for patients with extranodal NK/T-cell lymphoma, especially those in CR, with advanced disease (stage III/IV or EUNKTL) and high NKIPI scores.

Adolescent↗
PubMed2006

HER2 status in pure ductal carcinoma in situ and in the intraductal and invasive components of invasive ductal carcinoma determined by fluorescence in situ hybridization and immunohistochemistry.

AIM: To determine the HER2 status of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) of the breast. The increased prevalence of HER2 amplification and overexpression in DCIS is considered to be maintained in the intraductal component of IDC; however, HER2 amplification and overexpression are detected much less in IDC. METHODS AND RESULTS: Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) were performed to detect HER2 in 270 IDCs with an intraductal component and in 50 pure DCIS samples; IHC was also performed in 116 metastatic nodes. HER2 was found to be amplified in 77 cases (28.5%) and overexpressed in 79 (29.3%) of the 270 IDCs. HER2 amplification was similar between intraductal and invasive components of the same tumour. The concordance for HER2 status between invasive and intraductal components of individual tumours was 98.5% and 99.3% by FISH and IHC, respectively. HER2 was amplified in 25 (50%) of the 50 pure DCIS samples. HER2 overexpression in metastatic nodes resembled the HER2 status in the primary tumour for 108 (93.1%) of 116 cases (kappa =0.831). CONCLUSION: Our study indicates that the intraductal component of IDC may differ biologically when compared with pure DCIS. HER2 appears to lack a critical role in the progression from DCIS to IDC and HER2 status is maintained in metastatic lesions.

Adult↗
PubMed2006

Desipramine inhibits Na+/H+ exchanger in human submandibular cells.

A common and significant side-effect of the antidepressant desipramine is xerostomia (dry mouth). We investigated the effect of desipramine on Na(+)/H(+) exchanger, which is an important modulator of salivary secretion. In dissociated human submandibular acinar cells, desipramine inhibited intracellular pH recovery in a concentration-dependent manner. Likewise, 5-(N-ethyl-N-isopropyl)amiloride (EIPA), a Na(+)/H(+) exchanger inhibitor, had the same effect as desipramine, whereas the effect of 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS), a Na(+)/HCO(3)(-) co-transporter inhibitor, was not dramatic. Although desipramine is known to inhibit catecholamine re-uptake, desipramine also inhibited pH recovery in the human submandibular gland cell line, HSG cells, which lack nerve inputs. Our results suggest that desipramine directly inhibits Na(+)/H(+) exchange in human submandibular glands without the involvement of catecholamine re-uptake, revealing the cellular mechanism of desipramine-evoked xerostomia.

Adult↗
PubMed2006

Eugenol inhibits sodium currents in dental afferent neurons.

Although eugenol is widely used in dentistry, little is known about the molecular mechanisms responsible for its anesthetic properties. In addition to calcium channels, recently demonstrated by our group, there could be another molecular target for eugenol. Using a whole-cell patch-clamp technique, we investigated the effect of eugenol on voltage-gated sodium channel currents (I(Na)) in rat dental primary afferent neurons identified by retrograde labeling with a fluorescent dye in maxillary molars. Eugenol inhibited action potentials and I(Na) in both capsaicin-sensitive and capsaicin-insensitive neurons. The pre-treatment with capsazepine, a competitive antagonist of transient receptor potential vanilloid 1 (TRPV1), failed to block the inhibitory effect of eugenol on I(Na), suggesting no involvement of TRPV1. Two types of I(Na), tetrodotoxin (TTX)-resistant and TTX-sensitive I(Na), were inhibited by eugenol. Our results demonstrated that eugenol inhibits I(Na) in a TRPV1-independent manner. We suggest that I(Na) inhibition by eugenol contributes to its analgesic effect.

Action Potentials↗
PubMed2005

Theoretical evidence for equivalence between the ground states of the strong coupling BCS Hamiltonian and the antiferromagnetic Heisenberg model.

By explicitly computing wave function overlap via exact diagonalization in finite systems, we provide evidence indicating that, in the limit of strong coupling, i.e., Delta/t--> infinity the ground state of the Gutzwiller-projected BCS Hamiltonian (accompanied by proper particle-number projection) is identical to the exact ground state of the 2D antiferromagnetic Heisenberg model on the square lattice. This identity is adiabatically connected to a very high overlap between the ground states of the projected BCS Hamiltonian and the t-J model at moderate doping.

Journal Article↗
PubMed2005

Salvage chemotherapy with irinotecan, 5-fluorouracil and leucovorin for taxane- and cisplatin-refractory, metastatic gastric cancer.

We performed a phase II study of combination chemotherapy with irinotecan, 5-fluorouracil (5-FU) and leucovorin in metastatic gastric cancer patients who were previously treated with taxane and cisplatin, to evaluate the antitumour activity and toxicity of the combination chemotherapy. The metastatic gastric adenocarcinoma patients who were previously treated with taxane and cisplatin combination as first line, and had at least one measurable lesion, 0-2 ECOG performance status and adequate organ functions, were considered eligible. They received irinotecan (150 mg m(-2), day 1) and leucovorin (100 mg m(-2), day 1), followed by continuous infusion of 5-FU (1000 mg m(-2) day(-1), days 1 and 2) every 2 weeks. Treatment was continued until progression of disease was observed. In all, 64 patients were treated with this combination chemotherapy. The median age of the patients was 55 years (range, 33-74 years), and the median ECOG performance status was 1 (0-1, 61 (95%)). Out of 64 patients, 57 were assessable for response. Among 57 assessable patients, no complete response and 12 partial responses were observed (overall response rate, 21%; 95% confidence interval (CI), 10-32%). Stable disease was observed in 14 patients (25%) and progressive disease in 31 patients (54%). The median time to progression was 2.5 months (95% CI, 1.6-3.4) and the median overall survival since the start of the second-line modified FOLFIRI was 7.6 months (95% CI, 6.5-8.7). Grade 3-4 haematologic toxicities included neutropenia in seven patients (11%) and thrombocytopenia in five patients (8%). Grade 3-4 nonhaematologic toxicities included diarrhoea in two patients (3%) and vomiting in two patients (3%). There were no treatment-related deaths. The combination of irinotecan, 5-FU and leucovorin showed moderate activity and favourable toxicity profile as a second-line treatment in metastatic gastric cancer patients, who were previously treated with taxane and cisplatin.

Adenocarcinoma↗
PubMed2005

Size-resolved kinetic measurements of aluminum nanoparticle oxidation with single particle mass spectrometry.

Aluminum nanoparticles are being considered as a possible fuel in advanced energetic materials application. Of considerable interest therefore is a knowledge of just how reactive these materials are, and what the effect of size on reactivity is. In this paper we describe results of size resolved oxidation rate using a recently developed quantitative single particle mass spectrometer (SPMS). Aluminum nanoparticles used were either generated by DC Arc discharge or laser ablation, or by use of commercial aluminum nanopowders. These particles were oxidized in an aerosol flow reactor in air for specified various temperatures (25-1100 degrees C), and subsequently sampled by the SPMS. The mass spectra obtained were used to quantitatively determine the elemental composition of individual particles and their size. We found that the reactivity of aluminum nanoparticles is enhanced with decreasing primary particle size. Aluminum nanoparticles produced from the DC Arc, which produced the smallest primary particle size (approximately 19 nm), were found to be the most reactive (approximately 68% aluminum nanoparticles completely oxidized to aluminum oxide at 900 degrees C). In contrast, nanopowders with primary particle size greater than approximately 50 nm were not fully oxidized even at 1100 degrees C (approximately 4%). The absolute rates observed were found to be consistent with an oxide diffusion controlled rate-limiting step. We also determined the size-dependent diffusion-limited rate constants and Arrehenius parameters (activation energy and pre-exponential factor). We found that as the particle size decreases, the rate constant increases and the activation energy decreases. This work provides a quantification of the known pyrophoric nature of fine metal particles.

Journal Article↗
PubMed2005

Nasal-type NK/T cell lymphoma: clinical features and treatment outcome.

Nasal-type NK/T cell lymphoma is an increasingly recognised disease entity of aggressive clinical behaviour. The objective of this study was to investigate clinical features and treatment outcomes in patients with nasal-type NK/T cell lymphoma. From January 1991 to December 2003, 26 patients diagnosed as nasal-type NK/T cell lymphoma were included in the analysis. One half of patients presented with poor performance status (ECOG > or =2); 46% of patients were categorised as high intermediate or high-risk group according to IPI; and 46% of patients were diagnosed at advanced stage. The median survival for 26 patients with nasal-type NK/T cell lymphoma was 7.4 months (95% CI, 0.1, 16.9). The treatment outcome of primary anthracycline-based chemotherapy was poor: 60% CR rate in localised disease and 0% CR rate in advanced disease. After a median follow-up of 24.4 months (range 3.1-99.0) in patients with localised disease who had achieved a CR (range 29.6-165.7), three patients (50.0%) developed disease recurrence at 6.1, 21.8, and 52.1 months, respectively, and all patients presented with locoregional failure. The predictive factors for poor survival were of age greater than 60, advanced stage and poor performance in multivariate analysis. In conclusion, Nasal-type NK/T cell lymphomas showed a poor response to the conventional anthracycline-based chemotherapy, and thus an investigation for an innovative therapy is urgently needed to improve survival in these patients.

Adult↗
PubMed2005

IMVP-16/Pd followed by high-dose chemotherapy and autologous stem cell transplantation as a salvage therapy for refractory or relapsed peripheral T-cell lymphomas.

The present study aimed to analyse the treatment outcome of IMVP-16/Pd (ifosfamide, methotrexate, etoposide and prednisone) followed by high-dose chemotherapy and autologous stem cell transplantation (HDC/ASCT) for patients with peripheral T-cell lymphomas (PTCLs) who were previously treated with CHOP. Since 1995, 32 PTCL patients were treated with IMPV-16/Pd. Nine of 32 patients achieved a response (5 demonstrating complete response (CR) and 4 partial response), with an overall response rate of 28.1% (95% onfidence interval 0.12-0.45). Considering histopathologic subtypes, 3 of 4 relapsed natural killer (NK)/T-cell lymphoma patients (75%) achieved CR, but only 1 of 6 in non-NK/T-cell lymphoma patients (16.7%) achieved CR (P = 0.19). Six of 9 IMVP-16/Pd sensitive patients underwent HDC/ASCT. Three of them relapsed after 3, 4 and 15 months, respectively, of HDC/ASCT. Estimated 3-year overall survival and progression-free survival rates were 14.2% and 12.2%, respectively. Multivariate analysis revealed that responsiveness to first-line CHOP was a significant prognostic factor (P < 0.05). These results indicate that IMVP-16/Pd followed by HDC/ASCT appears to be an effective salvage regimen, especially for NK/T-cell lymphoma.

Adolescent↗
PubMed2005

Eugenol inhibits calcium currents in dental afferent neurons.

UNLABELLED: Eugenol is a topical analgesic agent widely used in the dental clinic. To elucidate the molecular mechanism underlying its analgesic action, we investigated the effect of eugenol on high-voltage-activated calcium channel (HVACC) currents in dental primary afferent neurons, and with a heterologous expression system. Dental primary afferent neurons were identified by retrograde labeling with a fluorescent dye, DiI. Eugenol inhibited HVACC currents in both capsaicin-sensitive and capsaicin-insensitive dental primary afferent neurons. The HVACC inhibition by eugenol was not blocked by capsazepine, a competitive transient receptor potential vanilloid 1 (TRPV1) antagonist. Eugenol inhibited N-type calcium currents in the cell line C2D7, stably expressing the human N-type calcium channels, where TRPV1 was not endogenously expressed. Our results suggest that the HVACC inhibition by eugenol in dental primary afferent neurons, which is not mediated by TRPV1 activation, might contribute to eugenol's analgesic effect. ABBREVIATIONS: high-voltage-activated calcium channel, HVACC; transient receptor potential vanilloid 1, TRPV1; trigeminal ganglion, TG; dorsal root ganglion, DRG; capsazepine, CZP.

Anesthetics, Local↗
PubMed2005

Simple compressive method for treatment of auricular haematoma using dental silicone material.

Most of the previous treatment methods for auricular haematoma are inconvenient for both patients and doctors because they are time-consuming and complex and must be performed under sterile conditions. The purpose of this study was to evaluate the effectiveness of a simple compressive method using a dental (silicone) impression material and comparing it with other methods for treatment of auricular haematomas. The authors aspirated a haematoma and then placed a mixed base and catalyst of silicone putty material on the anterior and posterior surfaces of the auricle in the shape of an inverted U for seven days. From the 24 cases managed with this method, 23 cases (95.8 per cent) were successfully healed. Eight patients were treated with a collodion-cotton wool cast and 16 of 19 patients were successfully treated with dental cotton-wool rolls. The average number of those visiting the hospital was 2.7 for the collodion-cotton wool cast, 6.9 for the dental cotton-wool roll, and 3.1 for dental silicone. The mean treatment durations were 8.1 days for the collodion-cotton wool cast, 13.8 days for the dental cotton-wool roll, and 8.6 days for dental silicone. The authors believe that this compressive method using dental silicone material is simple and appropriate for the treatment of auricular haematoma.

Adolescent↗
PubMed2004

Chirality in quantum computation with spin cluster qubits.

We study corrections to the Heisenberg interaction between several lateral, single-electron quantum dots. We show, using exact diagonalization, that three-body chiral terms couple triangular configurations to external sources of flux rather strongly. The chiral corrections impact single-qubit encodings utilizing loops of three or more Heisenberg coupled quantum dots.

Journal Article↗