P1-12-15: Adjuvant Trastuzumab Effect on HER2−Positive Breast Cancers According to Hormonal Receptor (HR) Status: Crosstalk between ER and EGFR/HER2 Pathway May Prevent Trastuzumab from Improving Outcomes in HER2−Positive and HR-Positive Breast Cancers

Background: Crosstalk between growth factor receptor, especially the EGFR/HER2 pathway, and ER pathways has been associated with endocrine resistance. Thus, combination therapy targeting both ER and EGFR/HER2 signaling to block the crosstalk between these pathways and eliminate escape routes have been proven effective in both preclinical and clinical models. Anti-HER2 directed therapy has been reported to restore hormone sensitivity in HER2−positive breast cancers. Adding trastuzumab to conventional treatment has been a standard treatment of choice in HER2−positive breast cancer irrespective of hormonal receptor (HR) status. The purpose of the study is to evaluate adding effect of 1 year of trastuzumab to conventional adjuvant treatment in patients with HER2−positive breast cancer who received surgery according to HR status.

Patients and Methods: We retrospectively analyzed the clinicopathologic characteristics and outcomes of 618 postoperative HER2−positive breast cancer patients between 2001 and 2008 at the Samsung Medical Center. Most of HER2−positive patients in our institute were treated with 1 year of trastuzumab as a part of adjuvant therapy since 2007 (post-trastuzumab era) compared with 2000–2006 (pre-trastuzumab era). Clinical outcomes including recurrence-free survival (RFS) were analyzed between pre-trastuzumab and post-trastuzumab era according to HR status. We performed Cox regression multivariate analysis for relapse using variables from univariate analysis by log-rank test for relapse. Clinical presentations and clinicopathologic characteristics were evaluated at the time of recurrence between both eras.

Results: The median age at diagnosis was 46 years (range, 22–79). During the median 60.0 months of follow-up, the 5-year recurrence rate was 20.2%. The 618 patients were divided into two groups (patients who received (n=175) and did not receive (n=443) adjuvant trastuzumab). Recurrence rate was much lower in post-trastuzumab era than in pre-trastuzumab era (13.6% vs. 32.3%, p<0.0001). Improving outcomes due to adding trastuzumab in patients with HER2+ve/HR-ve patients showed significant benefit from trastuzumab throughout the follow-up period (p=0.004). However, this improving effect appeared not to be consistent with statistical significance in HER2+ve/HR+ve patients (p=0.135). The analyses were performed according to quantitative ER Allred scores in HER2+ve/ER+ve patients, the effect of adding trastuzumab appeared to be mitigated as time over without any statistical significance (p=0.975). Young age (≤35) (hazard ratio (HR) 2.4, p<0.0001), trastuzumab use (HR 0.4, p=0.001), and node positivity (HR 2.8, p<0.0001) were identified as independent prognostic factors for recurrence in Cox-regression multivariate analysis. Limiting to HER2+ve/ER+ve patients, the statistical significances of trastuzumab use as independent factors were not maintained in Cox-regression models (p=0.074 for trastuzumab use).

Conclusion: Cross-talk between ER and EGFR/HER2 pathways may mitigate trastuzumab effect in HER2+ve/ER+ve breast cancers. Further study is warranted.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-15.

P2-12-19: Nomogram To Predict Recurrence and To Avoid Unnecessary Adjuvant Chemotherapy Based on Ki67 Index and ER Status in Hormone Receptor (HR)-Positive Breast Cancers with Low Number of Nodal Metastases (≤3) (NCT01273415)

Background

Hormone receptor (HR) positive breast cancers characterized with ER-associated genes are differentiated luminal B from luminal A tumors mainly by proliferation genes. According to NCCN guideline 2011, node positivity has been a main determinant to decide adjuvant chemotherapy with category 1. However, the experts’ panel at the St. Gallen Consensus in 2009 do not provides definite indications to give or withhold chemotherapy in patient group with intermediate criteria including low numbers (1-3, N1) of involved lymph nodes. Thus, in cases of limited number of nodal metastases, the role of biologic factors including Ki67 index needs to be defined. The aims of this study are to evaluate of Ki67 index as a useful surrogate marker to predict recurrence and to avoid unnecessary adjuvant chemotherapy and to develop nomogram based on Ki67 index to determine adjuvant therapeutic options in HR-positive in N0 and N1 breast cancers.

Patients and Methods

We retrospectively analyzed the clinicopathologic characteristics and outcomes of 953 postoperative HR-positive N0 and N1 breast cancer patients between 2004 and 2007 at the Samsung Medical Center. We constructed nomogram based on Cox regression model using independent factors demonstrated in multivariate analysis and validated externally in a cohort of 895 patients treated at Seoul National University Hospital.

Results: In Cox regression multivariate analysis, ER-ve/PgR+ve and Ki67 index were identified as independent factors.

Catastrophic massive intracardiac thrombus in a 40-year-old patient with dilated cardiomyopathy

Dilated cardiomyopathy has been associated with left ventricular (LV) thrombosis which leads to substantial morbidity and mortality as a site for systemic emboli. We report an interesting case of a stroke and acute limb ischemia secondary to a large mobile pedunculated LV thrombus in 40-year-old patient with dilated cardiomyopathy.

Characterization of nalidixic acid-resistant and fluoroquinolone-reduced susceptible Salmonella Typhimurium in swine

From 2001 to 2008, a total of 27 isolates of Salmonella enterica serovar Typhimurium were obtained from 930 swine. All 27 isolates were resistant to streptomycin and tetracycline. Seventeen isolates were multidrug resistant to more than three antimicrobial agents. Seven of these multidrug-resistant isolates were pentaresistant to ampicillin, chloramphenicol, streptomycin, tetracycline, and nalidixic acid. Among 27 isolates, 14 isolates (51.8 %) were nalidixic acid resistant (MIC, ≥128 μg/ml) and had reduced susceptibility to various quinolones (MIC, 0.125 to 2 μg/ml). When quinolone resistance-determining regions in the gyrA and gyrB genes of these isolates were sequenced, 13 isolates had Asp87→Tyr mutations and 1 isolate had Asp87→Gly mutation in the quinolone resistance-determining region of gyrA, whereas no mutation was found in gyrB. Genes for qnrA, qnrB, and qnrS were not detected by PCR with specific primers. Pulsed-field gel electrophoresis of genomic DNA digested with Xba I showed two patterns suggesting a clonal spread of Salmonella Typhimurium in swine in Korea.

Abstract P2-06-01: Ki67 Proliferative Index as an Invaluable Biomarker in Hormone Receptor (HR)-Positive Breast Cancer: Ki67 Labelling Index Can Reflect the Differences between Luminal A and B Subtypes Better Than HER2 Expression

Background: Differentiation by multigene signatures with excellent performance of hormone receptor (HR)-positive BC largely related to their proliferation genes. Despite questions about its usefulness, there is increasing evidence that Ki67 is a valuable prognostic marker. Standardization of Ki67 pathological assessment is the main problem to interpret reported trials.

The aims of the study are to evaluate the role Ki67 as prognostic marker to predict relapse in HR-positive BC patients (luminal A and B) in adjuvant setting using prospective patients’ cohort. In addition, cut-off value and significant level of Ki67 were investigated comparing with other biomarkers including HER2 in luminal BCs.

Method: We retrospectively analyzed the clinicopathologic characteristics of 1,070 postoperative breast cancer patients including Ki67 and clinical outcomes in terms of relapse free survival (RFS) between 2004 and 2007 at the Samsung Medical Center. Ki67 labelling index was measured in quantitative and semiquantitative method, independently. The percentage of positive nuclei stained for Ki67 was calculated each section based on the approximately 1,000 carcinoma cell nuclei. In addition, Ki67 was graded on a scale from 0 to 4, where 0 = staining of 0-4% of tumor cells, 1 = staining of 5-25% of tumor cells, 2 = 26-50% of tumor cells, 3 = staining of 51-75% of tumor cells, and 4 = staining of more than 76% of tumor cells. ROC curve was drawn to evaluate the usefulness of Ki67 index to get AUC then, find out the proper cut-off value of Ki67 to predict relapse. Multivariate analyses with Cox-regression model were performed. Results: Among 1,564 patients who received curative surgery for invasive breast cancer from January 2004 to June 2007, 1,070 patients with HR-positive were included in this analysis excluding 494 with HER2-enriched or triple negative breast cancer patients. Median follow-up duration was 56.9 months (range 36-77 months). Median age was 46 years (range 22-83 years). Ki67 threshold >19.5%, corresponding to a sensitivity 78.3%, a specificity 51.6% was chosen as cut-off value for relapse in adjuvant patients’ cohort. The AUC was 0.689 (P<0.0001 by Mann-Whitney U test). Overall relapse rate was 5.6%. In univariate analysis by log-rank test for relapse, ER negativity (p=0.010), HER2 positivity (p=0.017), histologic (p=0.001), and nuclear grade (p=0.012), lymphovascular invasion (P<0.0001), TNM stage (0.001), and Ki67 (P<0.0001) were identified risk factors to predict relapse. However, ER negativity, Ki67, and stage were identified as independent risk factors for relapse (Hazard Ratio (HR) 2.7, p=0.031 for ER negativity, HR 3.4, p <0.0001 for Ki67, HR 1.6, p=0.017 for stage) in Cox-regression multivariate analysis. Conclusion: Ki67 could strongly predict clinical outcomes for patients with luminal. 19.5% may be useful cut-off value of Ki67 labelling index. Ki67 may be a better biomarker to predict clinical outcomes than HER2 expression in luminal BCs. ER-/PR+ subset probably has different biology with other luminal BCs. Prospective clinical trials to choose therapeutic option using Ki67 are warranted.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-01.

Abstract P5-05-13: HER2-Induced MMP-1 Expression Is Mediated by HER1 Though AR, EGF, and TGF Independent of HER3 through HRG in Breast Cancer Cells

introduction. However, one of plausible explanation for resistance to trastuzumab is associated with HER dimerization. Furthermore, HER3 seems to be the preferred dimerization partner when signaling occurs through the PI3K pathway and, as such, is emerging as a key target for inhibition of HER signaling. Recently, we reported that HER2 could induce enhanced MMP-1 expression. In addition, this up-regulation of MMP1 expression was shown to be mediated MAPK pathway synergized with ER. Heregulin (HRG) acts as a preferential ligand for HER3 and/or HER4 receptors. Upon binding, HRG activates the EGFR/HER2 receptors via dimerization with HER3 and/or HER4. In the other words, HRG-β was reported to promote MMP-7 expression via HER2-mediated AP-1 activation in MCF-7 cells. In addition, MMP-9 is associated with HRG-≥1/HER2 aggressive phenotype of breast cancer.

Based on these backgrounds, we conducted this study to test the role of HER3 in breast cancer cells in relation to the expression of HER2 and MMP-1.

Our result showed that MMP-1 and MMP-13 expressions were up-regulated via EGF and amphiregulin (AR) independent of HRG in HER2 transfected MCF-7 and SK-BR-3 breast cancer cells through Western immunoblotting and quantitative RT-PCR. Enhanced MMP-1 and MMP-13 expressions were markedly decreased by treating HER2 targeting agents in AR, EGF, and TGF-β stimulating cell lines, while these findings were not observed in HRG1-β and HRG1-β stimulating cell lines in quantitative RT-PCR. In addition, these findings were reversed by treating siEGFR and siHER2, not by siHER3. Consequently, we could confirm the downstream pathways were mediated by MMP-1 AP-1 not by HRG1-β, nor HRG1-β with EMSA.

This study showed that HER2-induced MMP-1 expression was mediated by HER1 though AR, EGF, and TGF independent of HER3 through HRG in breast cancer cells. This result implies that the dimerization responsible for MMP-1 up-regulation by HER2 is HER1/HER2, not HER2/HER3. Further implications of MMP-1 in HER2 overexpressing breast cancer through HER1 are going to following.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-13.

Abstract P6-13-05: Differences of Clinical Manifestations and Therapeutic Outcomes in Leptomeningeal Metastases (LM) According to Breast Cancer Subtypes

Backgrounds: Breast cancer is the solid tumor most commonly associated with leptomeningeal metastases (LM). Therapeutic modalities include intrathecal and systemic chemotherapy, radiotherapy and other palliative modality including placement of a ventricular reservoir. The aim of this study is to characterize clinical feature and outcomes of LM according to breast cancer subtypes in conjunction with whole CNS metastases.

Methods: A retrospective study was performed on breast cancer patients with LM who received palliative management at Samsung Medical Center between 1994 and 2008. Among 281 metastatic breast cancer patients, 71 breast cancer patients with LM were identified. They were divided into three biological subgroups. The propensity of biological subtypes for LM, clinical manifestation including recursive partitioning analysis of Radiation Therapy Oncology Group (RPA RTOG) prognostic class, and therapeutic outcomes were assessed.

Results: The median age was 48 (range 26-70) years. The rates of the patients with triple negative breast cancer (TNBC), human epidermal growth factor receptors 2 (HER2)-positive and hormone receptor (HR)- positive subtype breast cancer were 26 (44%), 15 (25%) and 18 (31%), respectively. Sixty-four patients (90%) had metastatic disease at sites other than LM. TNBC were more common in RPA RTOG prognostic class III than those in HER2 and HR-positive subtypes (61% vs 39% vs 0%, P<0.0001). CNS including LM was the first site of distant metastasis in 65% of the TNBC patients. Treatment includes intrathecal chemotherapy (IT), whole brain radiotherapy (WBRT), and systemic chemotherapy. The median survival duration from the diagnosis of LM to death (OS-LM) was 4.5 months (range 0.2-26.4 months). Main causes of death were deterioration of neurologic sequelae associated with LM (55%), systemic disease progression (27%), and et cetera (18%). Death rates related with LM at each subtype were 64% for TNBC, 36% for HER2-positive, and 0% for HR-positive patients (p=0.060). In the univariate analysis, RPA RTOG classification (p=0.003), systemic disease control at LM (p=0.041), cytologic negative conversion to IT (p=0.001), systemic chemotherapy after LM diagnosis (p=0.002), and combined modality for LM treatment (p=0.005) were singled out as having prognostic value for OS-LM. Cox-regression multivariate analysis showed that RPA class (HR (Hazard Ratio) 1.8, p=0.022), cytologic negative conversion to IT (HR 0.4, p=0.043), and systemic chemotherapy (HR 0.24, p=0.004) are identified as independent prognostic factors.

Conclusion: TNBC and HER2-positive breast cancer appeared to have special predilection for LM as well as brain parenchymal metastases. High RPA class of TNBC may reflect more aggressive tumor biology in this sanctuary area. OS-LM depended on RPA class, cytologic negative conversion, and the use of systemic chemotherapy. The role of systemic chemotherapy and active local treatment modalities according to subtypes should be defined to improve dismal prognosis.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-13-05.

The CT and F-FDG PET/CT appearance of primary renal malignant fibrous histiocytoma

Renal malignant fibrous histiocytoma (MFH) is a rare, primary renal tumour. Imaging findings of renal MFH, including ultrasound, CT and MRI, have, however, been reported. As to the best of our knowledge (18)F-FDG PET/CT imaging of renal MFH has not been previously reported, we present the CT and (18)F-FDG PET/CT appearance of a pathologically proven primary renal MFH.

In vitro antimicrobial effect and in vivo preventive and therapeutic effects of partially purified lantibiotic lacticin NK34 against infection by Staphylococcus species isolated from bovine mastitis

Lantibiotics are small (<5 kDa), polycyclic peptides produced by gram-positive bacteria; they are also known as gram-positive bacteriocins. The high antimicrobial activity of lacticins and the continuing appearance of antibiotic-resistant bacteria in recent years have resulted in a renewed interest in lantibiotics. A partially purified form of lacticin NK34 (a Lactococcus lactis product isolated from the Korean fermented fish jeotgal) was tested to determine its antimicrobial effects against Staphylococcus aureus (n=20) and coagulase-negative Staphylococcus (CNS, n=20) strains isolated from the raw milk of cows with subclinical bovine mastitis in the present study. The spot-on-lawn assay was used to identify the 2 strains from each group with the greatest lacticin NK34 susceptibility, and the minimal lethal dose (MLD) was measured in ICR (imprinting control region) mice. The preventive and therapeutic effects of lacticin NK34 on the mouse infection model were determined for the first time. Lacticin NK34 demonstrated antimicrobial effects in 14 of 20 (70%) S. aureus indicator strains and in 18 of 20 (90%) CNS strains. Staphylococcus aureus 69 and S. simulans 55 demonstrated the greatest susceptibility to lacticin NK34 in the spot-on-lawn assay. The S. aureus 69 MLD was measured at 1.53 x 10(9) cfu/mouse, whereas the S. simulans 55 MLD was 3.59 x 10(9) cfu/mouse. Mice infected experimentally with S. aureus 69 MLD or S. simulans 55 MLD were treated with lacticin NK34. Treated mice demonstrated an 80% survival rate (48 of 60 mice) compared with a survival rate of 7.5% (3 of 40 mice) in control mice treated with distilled water. These data suggest that lacticin NK34 might be useful in the control of bovine mastitis and systemic bacterial infection.

Fabrication of Coaxial Si(1-x)Ge(x) Heterostructure Nanowires by O(2) Flow-Induced Bifurcate Reactions

We report on bifurcate reactions on the surface of well-aligned Si(1-x)Ge(x) nanowires that enable fabrication of two different coaxial heterostructure nanowires. The Si(1-x)Ge(x) nanowires were grown in a chemical vapor transport process using SiCl(4) gas and Ge powder as a source. After the growth of nanowires, SiCl(4) flow was terminated while O(2) gas flow was introduced under vacuum. On the surface of nanowires was deposited Ge by the vapor from the Ge powder or oxidized into SiO(2) by the O(2) gas. The transition from deposition to oxidation occurred abruptly at 2 torr of O(2) pressure without any intermediate region and enables selectively fabricated Ge/Si(1-x)Ge(x) or SiO(2)/Si(1-x)Ge(x) coaxial heterostructure nanowires. The rate of deposition and oxidation was dominated by interfacial reaction and diffusion of oxygen through the oxide layer, respectively.

Distribution of streptogramin resistance genes and genetic relatedness among quinupristin/dalfopristin-resistant Enterococcus faecium recovered from pigs and chickens in Korea

Fifty-four quinupristin/dalfopristin-resistant Enterococcus faecium (QDREF) isolated from chickens and pigs during 2002-2003 in Korea were screened by PCR for the presence of streptogramin resistance genes vatD, vatE, and vgbA, and macrolide resistance gene ermB. None of the QDREF isolates carried vgbA and vatD genes, while vatE and ermB were detected in 9.2% and 74% of the isolates, respectively. Twenty-six percent (14/54) of the QDREF isolates contained none of the resistance determinants tested. Pulsed-field gel electrophoresis (PFGE) patterns revealed high heterogeneity: 47 different patterns for 54 QDREF evaluated. Identical PFGE types were observed in two pairs of chicken isolates and a pair of pig isolates, respectively, but chicken isolates did not share PFGE pattern with pig isolates, suggesting clonal spread of QDREF strain between the same species of animals but not between different species of animals. This is the first report, to our knowledge, of vatE-positive E. faecium isolates and also the first evidence of clonal spread of QDREF strain between animals in Korea.

Palliative atrial switch operation in a 22-year-old patient with transposition of the great arteries

A 2-year-old boy was diagnosed as having transposition of the great arteries (TGA) and ventricular septal defect (VSD) and underwent pulmonary artery banding. The patient showed slow progression of cyanosis and dyspnea on exertion. Oxygen saturation was 70-75 % and cardiac catheterization showed severe pulmonary hypertension. At the age of 22, the patient underwent a palliative atrial switch operation; oxygen saturation increased to around 95 % and the patient experienced relief of symptoms. Atrial fibrillation and right side pleural effusion occurred but resolved and the patient was discharged.

Platinum assisted vapor-liquid-solid growth of er-si nanowires and their optical properties

We report the optical activation of erbium coated silicon nanowires (Er-SiNWs) grown with the assist of platinum (Pt) and gold (Au), respectively. The NWs were grown on Si substrates by using a chemical vapor transport process using SiCl4 and ErCl4 as precursors. Pt as well as Au worked successfully as vapor-liquid-solid (VLS) catalysts for growing SiNWs with diameters of ~100 nm and length of several micrometers, respectively. The SiNWs have core-shell structures where the Er-crystalline layer is sandwiched between silica layers. Photoluminescence spectra analyses showed the optical activity of SiNWs from both Pt and Au. A stronger Er3+ luminescence of 1,534 nm was observed from the SiNWs with Pt at room- and low-temperature (25 K) using the 488- and/or 477-nm line of an Ar laser that may be due to the uniform incorporation of more Er ions into NWs with the exclusion of the formation of catalyst-induced deep levels in the band-gap. Pt would be used as a VLS catalyst for high performance optically active Er-SiNWs.

Vector prime protein boost vaccination in the setting of myeloablative-induced lymphopenia suppresses growth of leukemia and solid tumors

We have developed a vaccine, which is designed to induce tumor-associated antigen (TAA)-specific T cells and antibodies in the setting of profound lymphopenia induced by myeloablative therapy and T-cell-depleted bone marrow transplantation. Test mice were injected subcutaneously (sc) with the 32DP210Bcr-Abl cell line, which is positive for the p210Bcr-Abl protein (Group 1). In Group 2, 7 days after injection of the 32DP210Bcr-Abl positive cell line, the mice received 900 cGy total body irradiation (TBI) followed in 1 h by the intravenous infusion of 10 million T-cell-depleted syngeneic bone marrow cells (TCDBMT) (Group 2). The leukemia-bearing group received an intravenous injection of 10 million spleen cells (donor lymphocyte infusions) from unvaccinated (Group 3) and TAA/ecdCD40L-vaccinated (Group 4) syngeneic mice 3 days after completion of the TBI and TCDBMT. Groups 3 and 4 mice received three additional sc vaccinations at 7-day intervals with the TAA/ecdCD40L vaccine, in which the TAA was taken from the junctional peptide of the P210bcr-Abl protein. The survival of Groups 3 and 4 mice was significantly longer than that in Groups 1 and 2 mice. Vaccinated mice from Group 4, which developed complete responses, survived up to 350 days post-injection of the leukemia cells without any evidence of leukemia regrowth.

Improved islet yields after purification following the novel endogenous trypsin inhibitor and histidine-tryptophan-ketoglutarate treatment in pigs

BACKGROUND

Adult porcine islet xenotransplantation into humans is greatly diminished by the difficulty to isolate islets because of their fragility. The goal of this study was to improve the efficacy of islet yields using endogenous trypsin inhibitor and histidine-tryptophan-ketoglutarate (HTK) perfusate.

METHOD

We compared two porcine islet isolation protocols: Eurocollins solution for in situ pancreas perfusion without use of an endogenous trypsin inhibitor versus HTK solution including endogenous trypsin inhibitor for pancreas perfusion.

RESULTS

Endogenous trypsin inhibitor and HTK strategies significantly improved total islet yield, recovery, and islet index after purification (P < .05), whereas unpurified islet yield did not increase. An average of 228,000 +/- 95,000 islet equivalents (IEQ) (n = 20) purified islets were obtained in the first group compared with 115,000 +/- 56,000 IEQ (n = 18) in the second group. The average islet index was significantly increased in the first group compared with the second group before and after purification: before: 0.28 versus 0.49 versus after: 0.25 versus 0.4 (P < .05). At this time, islet purity, viability, and stimulation index did not show a significant difference between groups.

CONCLUSION

Our study showed that endogenous trypsin inhibitor and HTK strategies significantly improved purified islet isolation efficacy because of reduction of islet fragility.

Experimental microencapsulation of porcine and rat pancreatic islet cells with air-driven droplet generator and alginate

Transplantation of microencapsulated islets is proposed as an ideal therapy for the treatment of type 1 diabetes mellitus without immunosuppression. This strategy is based on the principle that foreign cells are protected from the host immune system by an artificial membrane. The aim of this study was to establish an ideal condition of microencapsulation using an air-driven droplet generator and alginate in vitro. The optimal conditions for islet encapsulation were an alginate inflow rate of 10 mL/h, CO2 flow rate of 2.0 L/min in a concentration of 2% alginate. For 2.5% alginate, the alginate inflow rate of 20 mL/h, CO2 flow rate 3.0 L/min was ideal; alginate inflow rate of 40 mL/h, CO2 flow rate of 4.0 L/min showed good microcapsules at 3% alginate. Viability of encapsulated islets was greater than 90%. In terms of insulin secretion, encapsulated islets secreted insulin in response to glucose in static culture medium. However, there was no normal response to low or high glucose challenge with a stimulation index less than 2.0. Microencapsulation of pig islets was successfully performed with air-driven droplet generator and alginate in vitro. Further studies about biocompatibility and glucose control in vivo may provide a useful tool for treatment of patients with diabetes mellitus.

Sterilization effect of atmospheric plasma on Escherichia coli and Bacillus subtilis endospores

AIMS

Escherichia coli and Bacillus subtilis spores were treated with an atmospheric plasma mixture created by the ionization of helium and oxygen to investigate the inactivation efficiency of a low-temperature plasma below 70 degrees C.

METHODS AND RESULTS

An electrical discharge plasma was produced at a radio frequency (RF) of 13.56 MHz, connected to a perforated circular electrode with a discharge spacing of 1-15 mm. The discharge gas was helium with 0-2% oxygen. For the plasma treatment, a dried E. coli cell or B. subtilis endospore suspension on a cover-glass was exposed to oxygen downstream of the plasma from holes in an RF-powered electrode. The sterilization effect of the RF plasma was highest with 0.2% oxygen, corresponding to the maximum production of oxygen radicals.

CONCLUSIONS

Oxygen radicals generated by RF plasma are effective for the destruction of bacterial cells and endospores.

SIGNIFICANCE AND IMPACT OF THE STUDY

Low-temperature atmospheric plasma can be used for the disinfection of diverse objects, especially for the inactivation of bacterial endospores.

Antibiogram and coagulase diversity in staphylococcal enterotoxin-producing Staphylococcus aureus from bovine mastitis

We investigated antibiogram and coagulase gene diversity in staphylococcal enterotoxin (StE)-producing Staphylococcus aureus isolated from raw milk samples of cows infected with mastitis from 140 dairy farms in Korea between 1997 and 2004. Of the 696 Staph. aureus isolates collected in this study, 164 isolates (23.6%) produced one or more staphylococcal enterotoxins (A to D), and 19 isolates (2.7%) were methicillin-resistant. The percentage of StE-producing Staph. aureus (SES) isolates resistant to methicillin, kanamycin, neomycin, amikacin, and tetracycline was greater than that of non-SES. Ten coagulase genotype patterns were observed, including 4 main types comprising I (25.4%), II (13.9%), VII (13.2%), and VIII (17.8%). More than 4 Staph. aureus types were isolated from each of 82 dairy farms in different geographic locations, and only 1 coagulase genotype pattern was observed in 39 of the herds (47.6%). There was no significant correlation between coagulase genotypes harbored by Staph. aureus and their specific StE type. The percentage of isolates producing major StE types (A, B, AC, and ABCD) and being resistant to cephalothin and methicillin was greater among the Staph. aureus isolates with the 4 predominant coagulase genotypes (I, II, VII, and VIII) than among the isolates harboring the 6 rare coagulase types (III, IV, V, VI, IX, and X). Based on coagulase gene polymorphisms, our data indicate that a broad distribution of identical or closely related enterotoxin-producing Staph. aureus strains seem to contribute to bovine mastitis in the Republic of Korea.

Phenotypic and genetic antibiogram of methicillin-resistant staphylococci isolated from bovine mastitis in Korea

Staphylococcus aureus belongs to the group of major contagious mastitis pathogens, whereas the coagulase-negative staphylococci (CNS) are also capable of causing opportunistic bovine mastitis. Many of these strains are resistant to penicillin or ampicillin because of the long-term use of beta-lactam antibiotics in agricultural and healthcare settings. Based on the simple and highly specific coagulase genotyping by PCR-RFLP used for discriminating among Staph. aureus strains, the relationship between phenotypic antibiogram and the polymorphism of coagulase gene was determined in this study. The staphylococci strains (835 Staph. aureus and 763 CNS) were isolated from 3,047 bovine mastitic milk samples from 153 dairy farms in 8 provinces from 1997 to 2004 in the Republic of Korea. Twenty-one (2.5%) Staph. aureus and 19 (2.4%) CNS strains were resistant to methicillin [oxacillin minimum inhibitory concentration (MIC) > or = 4 microg/mL]. The mecA gene was also found in 13 methicillin-resistant Staph. aureus (MRSA) and 12 methicillin-resistant CNS (MRCNS) isolates with a significantly higher detection rate of the mecA gene in MRSA with high MIC (> or = 16 microg/mL) compared with those with MIC < or = 8 microg/mL. Methicillin-resistant Staph. aureus and MRCNS were also more resistant to other antibiotics (ampicillin, cephalothin, kanamycin, and gentamicin) than methicillin-susceptible staphylococci. Among 10 different coa PCR-RFLP patterns (A to J) in 706 Staph. aureus strains, the main types were A (26.9%), B (17.0%), G (10.5%), and H (15.4%), with the frequent observation of the A and H types (6 and 10 isolates) in MRSA. This study indicates that major epidemic Staph. aureus clones may be spread between different dairy farms, and the profile of coa genotype can be applied for epidemiological investigations and control of bovine mastitis, particularly one caused by MRSA with specific prevalent coa types.

The analysis of milk components and pathogenic bacteria isolated from bovine raw milk in Korea

Bovine mastitis can be diagnosed by abnormalities in milk components and somatic cell count (SCC), as well as by clinical signs. We examined raw milk in Korea by analyzing SCC, milk urea nitrogen (MUN), and the percentages of milk components (milk fat, protein, and lactose). The associations between SCC or MUN and other milk components were investigated, as well as the relationships between the bacterial species isolated from milk. Somatic cell counts, MUN, and the percentages of milk fat, protein, and lactose were analyzed in 30,019 raw milk samples collected from 2003 to 2006. The regression coefficients of natural logarithmic-transformed SCC (SCCt) on milk fat (-0.0149), lactose (-0.8910), and MUN (-0.0096), and those of MUN on milk fat (-0.3125), protein (-0.8012), and SCCt (-0.0671) were negative, whereas the regression coefficient of SCCt on protein was positive (0.3023). When the data were categorized by the presence or absence of bacterial infection in raw milk, SCCt was negatively associated with milk fat (-0.0172), protein (-0.2693), and lactose (-0.4108). The SCCt values were significantly affected by bacterial species. In particular, 104 milk samples infected with Staphylococcus aureus had the highest SCCt (1.67) compared with milk containing other mastitis-causing bacteria: coagulase-negative staphylococci (n = 755, 1.50), coagulase-positive staphylococci (except Staphylococcus aureus; n = 77, 1.59), Streptococcus spp. (Streptococcus dysgalactiae, n = 37; Streptococcus uberis, n = 12, 0.83), Enterococcus spp. (n = 46, 1.04), Escherichia coli (n = 705, 1.56), Pseudomonas spp. (n = 456, 1.59), and yeast (n = 189, 1.52). These results show that high SCC and MUN negatively affect milk components and that a statistical approach associating SCC, MUN, and milk components by bacterial infection can explain the patterns among them. Bacterial species present in raw milk are an important influence on SCC in Korea.

Prognostic significance of p53 gene mutations and protein overexpression in localized gastrointestinal stromal tumours

AIMS

Mutation of c-kit is a relatively early event in the tumorigenesis of gastrointestinal stromal tumours (GISTs). The aim was to determine the prognostic significance of p53 alterations as an additional genetic change in GISTs.

METHODS AND RESULTS

We reviewed 125 patients with localized GISTs subjected to complete resection between 1990 and 2002. Mutational analyses of c-kit exons 9, 11, 13 and 17, p53 exons 4-8 and immunohistochemistry for p53 protein were conducted using paraffin-embedded tissues. Alterations of p53 were observed in 50 patients (40.0%). Based on the National Institutes of Health's risk category, p53 alterations were noted more frequently in the higher risk categories (P = 0.041). With a median follow-up of 56.5 months (range: 2.3-126.8), 5-year relapse-free survival (RFS) rates were 61.7% without p53 alterations, compared with only 40.2% with p53 alterations (P = 0.009). Multivariate analysis indicated that p53 alterations comprised an independent, poor prognostic factor for RFS, in addition to c-kit mutations, large size, a high mitotic count and non-gastric primary sites.

CONCLUSIONS

Alterations in p53 were more commonly observed in localized GISTs at higher risk of relapse. This suggests that they are significant as an independent, poor prognostic factor.

Varying degrees of FDG uptake in multiple benign neurofibromas on PET/CT

We report fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings of three neurofibromas in the mediastinum and neck in a 26-year-old woman with neurofibromatosis type 1. PET/CT scans demonstrated varying degrees of FDG uptake with maximum standard uptake values (SUV(max)) of 5.3, 1.8 and 3.2 for left lower neck, left paratracheal and right paravertebral masses, respectively. Surgical resections were carried out and histopathology confirmed three benign neurofibromas with various tissue components and cellularities.