Rectal culture screening for vancomycin-resistant enterococcus in chronic haemodialysis patients: false-negative rates and duration of colonisation

Infection or colonisation with vancomycin-resistant enterococci (VRE) is common in chronic haemodialysis (HD) patients. However, there is limited information on the duration of VRE colonisation or on the reliability of consecutive negative rectal cultures to determine the clearance of VRE in chronic HD patients. Chronic HD patients from whom VRE was isolated were examined retrospectively. Rectal cultures were collected more than three times, at least one week apart, between 1 June 2003 and 1 March 2010. The results of the sequential VRE cultures and patients' data were analysed. Among 812 patients from whom VRE was isolated, 89 were chronic HD patients and 92 had three consecutive negative cultures. It took 60.7 ± 183.9 and 111.4 ± 155.4 days to collect three consecutive negative cultures in the 83 non-chronic haemodialysis patients and nine chronic HD patients, respectively (P = 0.011). The independent risk factors for more than three negative sequential rectal cultures were glycopeptide usage [odds ratio (OR): 2.155; P = 0.003] and length of hospital stay (OR: 1.009; P = 0.001). After three consecutive negative rectal cultures, two of six chronic HD patients and 10 of 36 non-HD patients were culture positive again. In conclusion, a significant proportion of patients colonised with VRE cannot be detected by three-weekly rectal cultures, and the duration of VRE colonisation in chronic haemodialysis patients tends to be prolonged. These results may be contributing to the continued increase in the prevalence of VRE.

Prognostic factors and survial of advanced renal cell carcinoma with predominant sarcomatoid histology

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Background: Sarcomatoid renal cell carcinoma (SRCC) is known to have aggressive clinical course and poor response to treatment. Very limited data of clinical feature, prognostic factor, and survival are available for advanced disease with predominant sarcomatoid histology. We evaluated clinical features, response to treatment, and prognostic factors for survival.

Methods: Between 2001 and 2010, 30 patients with metastatic or recurrent RCC with predominant sarcomatoid histology (sarcomatoid component 30% or more for resected kidney or exclusive sarcomatoid carcinoma on needle biopsy) were treated at our institution. We reviewed these patients' records to identify clinical and pathologic features which could affect survival. The role of nephrectomy and systemic therapy on patient outcome was also investigated.

Results: There were 20 male and 10 female patients with a median age of 58 years (range, 43–83). Twenty patients had initially metastatic disease and 16 patients (53%) had ECOG performance status (PS) of 0–1. The most frequent metastatic site was lung (57%) followed by bone (43%) and distant lymph nodes (23%). Fourteen (70%) out of 20 patients with initially metastatic disease underwent primary nephrectomy and six patients also underwent metastasectomy. The median % of sarcomatoid component was 80% (range, 30–100%). All patients (N=10) who received immunotherapy had progressive disease as their best response and only one out of 5 patients treated with sunitinib or everolimus had a partial response. With a median follow-up duration of 22 months, the median survival was 3.6 months (95% CI, 0∼7.5) with 6-month survival rate of 43%. Only ECOG PS had impact on survival (P<0.001: ECOG=0, 14.1 months; ECOG=1, 7.4 months; ECOG=2, 3.2 months, and ECOG=3, 1.64 months). Survivals for initially metastatic disease were not significantly different whether patients underwent nephrectomy or not (2.0 months vs. 3.4 months, HR=0.62, 95% CI, 0.16–2.44 after correcting for potential prognostic factors).

Conclusions: Patients with SRCC have a fulminant clinical course and the majority of patients had disease progression irrespective of any treatment. Only performance status dose have impact on overall survival.

No significant financial relationships to disclose.

Does hepatorenal syndrome affect the result of liver transplantation? Clinical observations

Hepatorenal syndrome (HRS) is a reversible, functional renal failure that occurs in patients with advanced hepatic failure. However, the reported rates of complete recovery of renal function and patient survivals after orthotopic liver transplantation (OLT) are variable. The aim of this study was to compare the outcomes after OLT between patients with HRS and those without HRS (no-HRS). We established exclusion criteria to select study patients who underwent OLT in a single center between January 2005 and October 2008. The exclusion criteria included the following: (1) malignancy, (2) <18 years of age, (3) other than primary OLT, (4) ABO mismatch or hemophilia, (5) no liver cirrhosis, and (6) survival >1 month after OLT. We selected 71 subjects, including 8 HRS and 63 no-HRS patients. No significant differences were observed in the estimated glomerular filtration rate (eGFR) between the 2 groups except for a lower eGFR on the day of and 1 month after OLT in the HRS group: 108.3 ± 40.5 versus 31.4 ± 14.1 mL/min and 85.4 ± 15.0 versus 57.3 ± 12.1 mL/min (P = .000 and P = .014, respectively). The renal function of 6/7 HRS patients who survived >1 year improved. The 1-year patient survival rate after OLT in HRS patients was similar to that without HRS: 95% versus 86% (P = .37). We concluded that HRS had minimal effects on patient survival and return of acceptable renal function.

Significance of Viral Reactivation in Hepatitis B Virus Carriers with Early Breast Cancer Receiving Anthracycline- or Taxane-Containing Chemotherapy

Background :It is known that cancer patients in healthy hepatitis B viral (HBV) carrier status are prone to develop hepatic dysfunction during cytotoxic chemotherapy. The objectives of this study were to determine the frequency of healthy HBV carrier status and subsequent viral reactivation resulting in hepatic dysfunction during cytotoxic chemotherapy, and its significance in early breast cancer patients.Methods :Among 3,433 patients with operable breast cancer diagnosed at the National Cancer Center, Korea between January 2001 and March 2009, 3,337 patients were tested for HBsAg. Retrospectively, medical records were reviewed for 139 (4.2%) patients who were positive for HBs Ag.Results :Of 139 patients, 112 patients received anthracycline or taxane based neoadjuvant (n=25) or adjuvant (n=87) combination chemotherapy. Prophylactic lamivudine therapy was administered in 33 patients (29.5%).Thirty of 112 (26.8%) patients developed reactivation of HBV with deterioration of hepatic function during chemotherapy. The rate of reactivaton was not different with or without further taxane therapy (43% vs. 44%, p=0.408).Although there was no significant difference in the rate of chemotherapy delay between two groups, the incidence of early termination of planned chemotherapy was higher in B viral reactivation group (23.3% vs. 4.9%, p=0.008). Within a median follow-up duration of 39 mo (range 1 mo to 95 mo), the rate of disease recurrence was comparable between two groups (10% vs. 18.3%, p=0.390).Lamivudine prophylaxis decreased the rate of HBV reactivation without statistical significance (15.1% vs. 35.4%, p=0.101). Despite more patients without prophylaxis developed G 3/4 AST/ALT elevation (40% vs. 84%, p=0.068), the majority of patients recovered to G 1/2 AST/ALT level within 12 months with anti-viral or supportive treatment (0% vs. 14.3%, p=1.00). One patient without lamivudine prophylaxis developed fulminant hepatic failure after 3rd cycles of neo-adjuvant chemotherapy and received living donor liver transplantation. After that, she received radical mastectomy and maintained adjuvant anti-hormonal therapy.Conclusions :Although lamivudine prophylaxis in HBV healthy carrier decreased the rate of viral reactivation during neo- or adjuvant chemotherapy, the majority of patients irrespective of prophylaxis recovered hepatic function in a year with conservative treatment. Early detection and intensive supportive care are as important as anti-viral prophylaxis in HBV healthy carrier when treated with cytotoxic chemotherapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1113.

Prognostic Factors for Locoregional Recurrence in Operable Breast Cancer Patients Treated with Preoperative Systemic Chemotherapy

Background: We aimed to evaluate the clinicopathologic factors affecting locoregional recurrence (LRR) in potentially operable breast cancer patients receiving preoperative systemic chemotherapy (PST).Methods: We reviewed the records of 316 breast cancer patients treated with PST (doxorubicin/cyclophosphamide, 101; docetaxel /capecitabine, 103; paclitaxel/gemcitabine, 43; doxorubicin/docetaxel, 69) followed by surgery and adjuvant radiotherapy between 2002 and 2006. The majority of patients had clinical positive axillary lymph nodes. To define the prognostic factors for LRR, age, clinical stage, hormone receptor (HR) and HER2 status, clinical and pathologic response, type of operation, pathological characteristics including tumor size, tumor grade, nodal status, number of positive axillary nodes, size of metastatic lymph node and status of resection margin and tumor multiplicity before and after PST were analyzed.Results: Overall 52 patients (16.5%) in the primary tumor and 87 patients (27.5%) in the axillary nodes achieved a pathologic complete response (pCR), and 206 patients (65.2%) underwent breast conserving surgery (BCS). With a median follow-up of 52.4 month (range: 4.7 - 89.4), total 18 (5.7%) patients developed LRR; 2 of 110 (1.8%) patients with mastectomy vs. 16 of 206 (7.7%) patients with BCS (p=0.04). Other significant factors in the univariate analysis were clinical T stage, HR status, clinical response and tumor multiplicity. A pCR in the primary tumor or node was not a prognostic factor for LRR in this study. In multivariate analysis, clinical T stage (T3/4, HR 7.8; 95% CI, 2.33-26.24; P=0.001), hormone receptor status (negative, HR 6.2; 95% CI, 1.91-20.22; P=0.002) and type of surgery (BCS, HR 9.5; 95% CI, 1.97-46.37; P=0.005) were independent prognostic factors. Among patients with BCS, advanced clinical T stage (HR 12.4; 95% CI, 3.45-44.56; P&lt;0.001), negative hormone receptor (HR 4.74; 95% CI, 1.33-16.96; P=0.02), non-responding disease (HR 6.54; 95% CI, 1.07-40.12; P=0.04) and multiple tumors (HR 4.36; 95% CI, 1.06-17.90; P=0.04) developed more frequent LRR.Conclusions: Significantly more patients with advanced clinical T stage, negative HR status and BCS developed LRR in operable breast cancer treated with PST. Moreover, in patients with BCS after PST, clinically non-responding disease and multiple tumors showed unfavorable prognosis besides the larger tumors and negative hormone receptor.Partly supported by NCC Grant No 0610240

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1095.

New HER2 Assay Using Trastuzumab for the Selection of Trastuzumab Responding Breast Cancer: The Positivity Is Significantly Associated with Pathologic Complete Response after Preoperative Chemotherapy

Background:The evaluation of HER2 status is required for trastuzumab therapy in breast cancer. Although there are a few methods for an evaluation of HER2 status, theoretically the better method would be to check trastuzumab uptake itself in the tumor after trastuzumab administration. Therefore, we developed a different HER2 test (QHerceptest) using trastuzumab to improve an accuracy in the selection of patient for trastuzumab therapy.Patients and Methods:31 patients with HER2 positive (IHC 3+: 19 and IHC 2+ with FISH positive: 12) early breast cancer who were enrolled in a phase II preoperative paclitaxel, gemcitabin and trastuzumab (PGH) combination chemotherapy trial were evaluated. The pre-chemotherapy tumor specimens were obtained from the breast mass (n=24) or metastatic lymph nodes (n=7). After completing 6 cycles of PGH therapy, all patients underwent breast conserving surgery or mastectomy. We applied trastuzumab and Quantum dot conjugated goat anti-human IgG (QD-IgG, 655nm, Invitrogen) in the process of immunuhistochemistry for HER2 using formalin-fixed paraffin embedded specimen. After antigen retrieval, trastuzuamb was applied followed by QD-IgG. The result of QHerceptest was scored as negative, weak positive, moderate positive, or strong positive, and its relative uptake (RU) were quantified by imaging analysis program (Q-IHC, http://www.bio-miblab.org).Results:The uptake of trastuzumab by QHerceptest was heterogenous, varying between 1.3% to 193.7%. Twenty one of 31 (67.7%) patients achieved pathologic complete response (pCR): 11 of 12 patients (91.7%) with QHerceptest strong positive tumors, 6 of 9 patients (66.7%) with QHerceptest moderate positive tumors, and 4 of 7 patients (57.1%) with QHerceptest weak positive tumors, and none of 3 patients (9.4%) with QHerceptest negative tumors (p=0.0203). Besides, RU was significantly different between non-pCR and pCR groups (43.9±38.3, 80.8±47.1, p=0.0396)Conclusion:We developed a new HER2 assay using trastuzumab and applied to clinical specimen. This assay showed heterogenous trastuzumab uptake in this patient population. Although the data need to be verified by further study, the assay could possibly eliminate patients among HER2 positive breast cancer who will not get benefit by trastuzumab .This study was supported by NCC Grant No 0710292-2 and NCC Grant No 0610240.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6050.

Prognosis of Metaplastic Breast Cancer: Poorer Than the Rest of Triple-Negative Breast Cancer

Background: The biologic behavior of metaplastic breast cancer (MBC) has not been well elucidated due to its rarity and heterogeneity. This study was designed to assess the clinical and tumor characteristics and outcomes of MBC patients as compared with invasive ductal carcinoma (IDC) in general and the triple-negative (TN) subtype.Materials and methods: This study included 35 MBC and 2,839 IDC patients diagnosed at the National Cancer Center, Korea between 2000 and 2008. We, retrospectively, reviewed the clinicopathologic characteristics and clinical outcomes.Results: The mean age was 47.4 years for MBC group and 48.3 years for IDC group. The MBC group presented with larger tumors (≥ T2, 78.8% vs 41.0%; P&lt;0.001), higher histologic grade (grade 3, 92.0% vs 44.6%; P&lt;0.001), fewer ER and PgR positivity (ER+, 14.3% vs 69.0% ; P&lt;0.001 and PgR+, 25.7% vs 66.1%; P&lt;0.001), higher Ki-67 expression (35.5%±26.2% vs 20.6% ±19.8%; P=0.024) and more TN subtypes (48.6% vs 11.9%; P&lt;0.001) than IDC group. Excluding de novo stage IV patients, 14 of 32 (43.7%) MBC patients and 260 of 2782 (9.4%) IDC patents developed disease recurrence with a median follow-up of 36.2 months (range, 4.9-117.8 months). MBC was a poor prognostic factor for disease recurrence in univariate and multivariate analysis (HR 5.19; 95% CI, 2.04-13.18; P=0.001). MBC patients demonstrated aggressive pathologic features and experienced more disease recurrence (HR 4.77; 95% CI, 1.99-11.44; P=0.001) even when compared with 330 patients with TN subtype.Conclusions:Patients with metaplastic breast carcinoma appeared to have inherent aggressive tumor biology with poorer clinical outcomes than those with IDC in general and TN subtype.Partly supported by NCC Grant No 0610240

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4057.

Single Nucleotide Polymorphisms of CYP19A1, rs10459592 and rs4775936 Predict Clinical Benefit of Letrozole in Patients with Metastatic Breast Cancer

BackgroundThe CYP19A1 gene encodes the enzyme aromatase, which is involved in the production of estrogen in various tissues. We evaluated the efficacy of an aromatase inhibitor, letrozole in metastatic breast cancer patients according to DNA polymorphisms of the aromatase gene CYP19A1.Patients and methodsPatients (n=113) with hormone receptor positive metastatic breast cancer were treated with letrozole. Monthly GnRH agonist was added in premenopausal patients. DNA was isolated from peripheral blood samples and was genotyped for 50 polymorphisms of CYP19A1 by iPLEX Gold assay based on matrix-associated laser desorptional ionization, time-of-flight mass spectrometry.ResultsAmong 50 examined single nucleotide polymorphisms (SNP), 10 SNPs were revealed as monomorphic for Korean population. After trimming of the data using HWE test, rs10459592 (T/G) and rs4775936 (C/T), which were located in exon I.6 of CYP19A, were significantly associated in an over-dominant model with higher disease control rate (CR+PR+SD≥ 6months) (HR=2.82 [95% CI 1.21-6.59], p=0.0149; HR=2.62 [95% CI 1.12-6.10], p=0.0238, respectively). In linkage disequilibrium analysis, these were strongly linked (D'=1.0, r2=0.936), and subsequent haplotype analysis showed a statistical significance with regard to higher disease control rate (HR=2.61 [95% CI 1.12-6.1], p=0.0238). Median time to progression (TTP) with a median follow-up of 85.7 months (range 9.7-107.4 months) was improved in patients having over-dominant form of rs10459592 without statistical significance (median 7.74 months [95% CI 6.48-9.00] vs. median 12.07 months [95% CI 8.87-15.26], p=0.147). In multivariate analysis, rs10459592 (HR=2.81 [95% CI 1.12-7.06], p=0.027) was an independent factor affecting disease control rate besides age (HR=1.06 [95% CI 1.01-1.12], p=0.019) and HER2 positivity (HR=0.25 [95% CI 1.12-7.06], p=0.027).ConclusionIn patients with hormone responsive metastatic breast cancer treated with aromatase inhibitor, letrozole, the presence of SNPs in the exon I.6 of CYP19A1, rs10459592 and rs4775936 were significantly associated with improved treatment efficacy. Although further study is needed, our data present possible candidate markers for the letrozole treatment in metastatic breast cancer. (NCC grant number 0910320-1)

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2117.

Single Nucleotide Polymorphism (SNP) in RASSF1 and Clinical Outcomes of Breast Cancer Patients Treated with Neoadjuvant Docetaxel/Doxorubicin Chemotherapy

PurposeThe tumor suppressor gene RASSF1 (Ras association domain family member 1) regulates cell cycle, progression, apoptosis, and microtubule stability, and is inactivated by promoter hypermethylation in breast cancer. We analyzed the SNPs in RASSF1 and their predictive and prognostic value in stage II or III breast cancer patients who received neoadjuvant docetaxel/doxorubicin chemotherapyMethodsA total of 139 stage II or III breast cancer patients who received neoadjuvant docetaxel/doxorubicin chemotherapy were enrolled in this study. The patients received three cycles of neoadjuvant chemotherapy followed by curative surgery, and received additional three cycles of docetaxel/doxorubicin chemotherapy as an adjuvant. Germline DNA from peripheral blood mononuclear cells was extracted. The genotypes were performed using Illumina GoldenGate® Assay. We analyzed 3 SNPs in RASSF1 genes: rs3213621 T&gt;C in 3'UTR, rs2073499 G&gt;A in intron, and rs2073498 C&gt;A in exon 3 Ala133Ser.ResultsThe overall radiologic response rate (RR) for neoadjuvant chemotherapy was 79.8% and 10 patients (7.2%) achieved a pathologic complete remission (pCR). None of the SNPs were correlated with radiologic RR or pCR rate. SNP in intron of RASSF1 (rs2073499) was associated with relapse free survival (RFS). RFS was longer in GA/AA genotype than GG genotype (Hazard ratio [HR]=0.374, p=0.034) After adjusting age and hormone status, prognostic value of RASSF1 SNP remained significant (HR=0.393, p=0.050). Other two SNPs were not significantly associated with RFS.ConclusionsThe GA/AA genotype in SNP of RASSF1 (rs2073499) is associated with significantly longer RFS than the GG genotype. Further research is warranted to identify the biologic characteristics of RASSF1.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6061.

Perceptions of the effectiveness of ethical guidelines: an international study of physicians

The intent of ethics is to establish a set of standards that will provide a framework to modify, regulate, and possibly enhance moral behaviour. Eleven focus groups were conducted with physicians from six culturally distinct countries to explore their perception of formalized, written ethical guidelines (i.e., codes of ethics, credos, value and mission statements) that attempt to direct their ethical practice. Six themes emerged from the data: lack of awareness, no impact, marginal impact, other codes or value statements supersede, personal codes or values dictate, and ethical guidelines are useful. Overall, codes were valued only when they were congruent with existing personal morality. The findings suggest the need to re-evaluate the purpose, content, and delivery of codes for them to improve their function in promoting ethical conduct.

Imaging considerations for in vivo 13C metabolic mapping using hyperpolarized 13C-pyruvate

One of the challenges of optimizing signal-to-noise ratio (SNR) and image quality in (13)C metabolic imaging using hyperpolarized (13)C-pyruvate is associated with the different MR signal time-courses for pyruvate and its metabolic products, lactate and alanine. The impact of the acquisition time window, variation of flip angles, and order of phase encoding on SNR and image quality were evaluated in mathematical simulations and rat experiments, based on multishot fast chemical shift imaging (CSI) and three-dimensional echo-planar spectroscopic imaging (3DEPSI) sequences. The image timing was set to coincide with the peak production of lactate. The strategy of combining variable flip angles and centric phase encoding (cPE) improved image quality while retaining good SNR. In addition, two aspects of EPSI sampling strategies were explored: waveform design (flyback vs. symmetric EPSI) and spectral bandwidth (BW = 500 Hz vs. 267 Hz). Both symmetric EPSI and reduced BW trended toward increased SNR. The imaging strategies reported here can serve as guidance to other multishot spectroscopic imaging protocols for (13)C metabolic imaging applications.

Association between P53 expression or TP53 codon 72 polymorphism and prognosis in patients with operated invasive breast cancer

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Background: The present study analyzed the impact of p53 expression and TP53 codon 72 polymorphism on the prognosis in patients with operated invasive breast cancer. Methods: Two hundred thirty-four patients with ductal breast cancer who underwent surgery with curative intent were enrolled in the present study. The tumor expressions of p53, ER, PR, and HER2 were graded immunohistochemically and TP53 codon 72 polymorphism was determined by a PCR-RFLP assay using genomic DNA extracted from paraffin-embedded tissue. Results: The median age was 49 (range, 24–82) years, and 134 (57.3%) patients were premenopause at the time of diagnosis. Pathologic stages after surgery were as follows: stage I (n=77, 32.9%), stage II (n=110, 47.0%), and stage III (n=47, 20.1%). Tumor overexpression of p53 protein was observed in 59 (25.2%) patients and was associated with an unfavorable relapse-free survival (RFS) in an univariate analysis adjusted to age, stage, and menstrual status. In a multivariate analysis, p53 overexpression was an independent prognostic factor for RFS (HR=2.36; 95% CI=1.09–5.13; p=0.030). However, no associations were observed between the genotype of TP53 codon 72 polymorphism and survival or clinicopathologic characteristics. Conclusions: Overexpression of p53 protein can be considered as a prognostic factor for RFS in the breast cancer patients after surgery.

No significant financial relationships to disclose.

Randomized phase II study of gefitinib alone or with simvastatin in previously treated advanced non-small cell lung cancer (NSCLC)

8057

Background: Statins reduce not only serum cholesterol levels but also mevalonate synthesis by inhibiting HMG-CoA reductase. Mevalonate is a precursor of several cellular major products including dolichol, geranylpyrophosphate (GPP) and farnesyl-pyrophosphate (FPP). Dolichol has a stimulatory effect on DNA synthesis and is linked to several tumor cell proteins. GPP and FPP cause isoprenylation of Ras and Rho those regulate signal transduction of several membrane receptors crucial for cell proliferation, differentiation, and apoptosis, which result in resistance to gefitinib. Thus depletion of mevalonate metabolites may enhance gefitinib activity in NSCLC. This study compared gefitinib alone with gefitinib plus simvastatin in patients with recurrent NSCLC after at least one chemotherapy. Methods: Between May 2006 and September 2008, 107 patients (51% male, 74% adenocarcinoma, 50% never-smoker, 54% more than two prior regimens) were randomly assigned to gefitinib alone (250 mg/d orally, n=53) or gefitinib plus simvastatin (250mg/d and 40 mg/d orally, respectively, n=54). A cycle was considered as 4 weeks of treatment. Therapy was continued until disease progression or intolerable toxicities. The primary end point was to assess response rate. Secondary end points included time to progression and survival. Median follow-up was 10.1 months. Results: Efficacy was similar for gefitinib and gefitinib plus simvastatin groups. Objective tumor response rates (RR) were 31.5% (95% CI, 19.1 to 43.9) and 32.1% (95% CI, 19.5 to 44.7); median PFS were 1.9 and 2.0 months; and median OS were 9.5 and 12.7 months, respectively. In subgroup analysis, gefitinib plus simvastatin showed a trend for higher RR than gefitinib alone in non-adenocarcinoma group (38.5% vs. 7.7%, p=0.08). Adverse events at both arms were generally mild (grade 1 or 2) and consisted mainly of skin reactions. Conclusions: Gefitinib combined with simvastatin did not improved efficacy compared to gefitinib alone in this unselected patient population, but showed a trend for higher efficacy in non-adenocarcinoma patients. Although it is preliminary, gefitinib combined with simvastatin showed slightly increased OS. Updated survival data will be presented.

No significant financial relationships to disclose.

Prognostic significance of preoperative serum tumor markers in the patients with curatively resected advanced gastric cancers

e15515

Background: We evaluated the prognostic significance of preoperative tumor markers, carcinoembryonic antigen (CEA), carbohydrate antigen 19–9 (CA19–9), and carbohydrate antigen 72–4 (CA72–4), in the patients with curatively resected advanced gastric cancers (AGC). Methods: Preoperative serum tumor markers were available for 667 patients who had been enrolled in a phase III trial of adjuvant chemotherapy (AMC0201). We compared the relapse free survival (RFS) and overall survival (OS) according to patient's pre-treatment clinical characteristics and serum tumor markers by using log rank test and Cox proportional hazard model. Results: Of total 667 patients, 3 year RFS rate and OS rate were 67.4% and 75.0%, respectively. Postoperative pathologic stage was II in 353 (52.9%), IIIA in 202 (30.3%), IIIB in 61 (9.1%), and IV (M0) in 51 (7.6%). CEA, CA19–9, CA72–4 were elevated pre-operatively in 64 of 665 patients (9.6%), 75 of 664 patients (11.3%), and 121 of 639 patients (18.9%), respectively. After the median follow-up of 38.4 months, 209 patients (31.3%) had recurrence, and 164 patients (24.6%) died. In the univariate analysis, location of tumor, type of surgery, Borrmann type, TNM stage, the elevation of CEA and CA72–4 level were significant prognostic factors for RFS and OS. In the multivariate analysis, serum CA72–4 was independent significant prognostic factor for RFS and OS as well as tumor location, Borrmann type, and stage Conclusions: Pre-operative serum CEA and CA72–4 levels were independent prognostic factors as well as clinical characteristics of pathologic stage, tumor location and Borrmann type in patients with curatively resected AGC.

No significant financial relationships to disclose.

Deformation of a LCD glass-panel by alignment process in nanoimprint lithography

Deformation of a LCD glass-panel during the alignment is analyzed for a UV-nanoimprint lithography process. In UV-nanoimprint processes for manufacturing LCD panels, a glass-panel should be aligned with respect to the position of fiducial marks on imprint mold and the target glass. The alignment process will place the nano-patterns on the mold into the designated position in the glass-panel. Usually, viscoelastic resin is laminated between the mold and glass-panel. The resin is solidified by ultra-violet light and is designed to be nano-patterns. Thus, shear force would be induced on the panel during alignment process. The shear force can cause deformation of glass-panel, which ultimately causes misalignment of nano-patterns. Thus, deformation analysis for the glass-panel in the alignment process is essential to enhance the accuracy and to reduce alignment cost in nano-imprint. In this work, deformation of the glass panel from the viscous force is calculated by using 'ALGOR' package. The mechanism of misalignment of nano-patterns due to the deformation is analyzed. Finally, the effect of misalignment is discussed, and the experimental results are also presented.

Triple negative phenotype: not affecting survival in young patients with operable breast cancer

Abstract #1083

Purpose: To investigate the clinicopathological characteristics and outcomes of triple negative breast cancer in young patients.&#x2028; Experimental Design: We analyzed 1,498 patients with primary invasive breast cancer who underwent surgery between January 2000 and December 2003. Patients were divided into those &lt; 40 and ≥ 40 years old and into triple negative and non-triple negative groups.&#x2028; Results: A total of 326 (21.8%) were aged &lt; 40; relative to patients ≥ 40 years old, the younger group showed larger tumor size, higher lymph node positivity, and elevated Ki-67 index. Recurrence-free survival (RFS; P = 0.0002) and overall survival (OS; P = 0.0483) were significantly lower in the younger group. Three hundred seventy four patients (25.0%) had the triple negative phenotype, and of which 93 (24.9%) were &lt; 40 years old. Univariate survival analysis showed that the triple negative phenotype was not a prognostic factor for either RFS or OS in the younger group. In the older group, however, the triple negative phenotype was a significant prognostic factor for both RFS (P = 0.0103) and OS (P = 0.0081) by univariate analysis, and it remained a significant prognostic factor for OS by multivariate analysis (hazard ratio, 1.9; 95% confidence interval, 1.09-3.44; P = 0.025). When the non-triple negative group was subdivided into luminal and HER2 subtypes, the HER2 subtype showed the worst OS in both age groups (P &lt; 0.001), followed by the triple negative group. However, the difference between the HER2 subtype and the triple negative group was significant only in the younger group (P = 0.0064), but not in the older group (P = 0.1446).&#x2028; Conclusions: Triple negative phenotype did not affect survival in patients &lt; 40 years old, because of the markedly poorer survival of non-triple negative tumors of the HER2 subtype in this age group.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1083.

Metaplastic breast carcinoma: clinicopathologic features and prognostic value of triple-negativity

Abstract #1085

Backgroud Metaplastic breast carcinomas (MBC) are a rare type of breast cancer comprising &lt;1% of all invasive breast cancers and are generally characterized by hormone receptor and human epidermal growth factor receptor 2 (HER2) negativity. There is a paucity of information on prognosis according to hormone receptor and HER2 expression for these rare tumors. The aim of this study was to compare the clinical features and prognosis, between triple negative metaplastic carcinoma (TNMC) and non-triple negative metaplastic carcinoma (NTNMC).&#x2028; Material and Methods We retrospectively analyzed MBC patients treated at Seoul National University Hospital between 1996 and 2006. Pathologic, immunohistochemical findings and clinical outcome information were reviewed.&#x2028; Results fifty-one patients were identified. The median age at presentation was 45.8 years (range: 27.3-83.8). Median tumor size at diagnosis was 3.0 cm (range: 0.8-12.0). 34 cases (66.7%) were node-negative, 16 (31.4%) node-positive, and 1 (2.0%) were missing. Estrogen receptor (ER)/progesterone receptor (PR) yielded negative results in 49 cases (96.1%) and 48 cases (94.1%), respectively. HER2 overexpression by immunohistochemistry was negative in 41 of 51 (80.4%). At median follow-up of 40.8 months, the 5-year overall survival rate and disease free survival were 73.9% and 64.9%, respectively. Non-triple negativity (p=0.031) correlated significant with overall survival in multivariate analysis.&#x2028; Of the 51 patients, 39 (76.5%) were TNMC, and 12 (23.5%) were NTNMC. In TNMC and NTNMC group, median ages were 45.6 and 51.5 years and tumor sizes were 3.0 cm and 3.0 cm, respectively. There were 12 patients (30.8%) in TNMC and 4 patients (33.3%) in NTNMC for lymph node metastasis. Two groups did not differ significantly by age, tumor size, or nodal status. Positive rates for ER, PR and HER2 were 16.7%, 25% and 83.3% in NTNMC. The 3-year overall survival rates in TNMC and NTNMC were 91.4% and 61.9%, respectively (p=0.029). As regards to 3-years disease-free survival, there was no statistically significant difference between TNMC and NTNMC (p=0.694, 75.8% versus 75.0%).&#x2028; Discussion MBC mainly has triple negative features. However, in subgroup analysis of MBC, non-triple negative group displayed a poor prognosis compared with triple negative group, which is contrary to the case of invasive ductal carcinoma of breast. Further research exploring mechanism of this result.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1085.

Remarkable complete pathologic response rate after preoperative paclitaxel, gemcitabine, and trastuzumab chemotherapy in HER2 positive stage II/III breast cancer: a phase II multicenter study

Abstract #5105

Background: Preoperative paclitaxel (P) and gemcitabine (G) combination therapy given on D1/D8 every 3 weeks (wks) for 4 cycles was well tolerated and effective in stage II/III breast cancer (BC) in our previous phase II study, with an 18% pathological complete response (pCR) rate. Adding trastuzumab (H) to the preoperative chemotherapy increases both of the clinical and pathological response rates in HER2 positive BC patients (pts). Thus far, the highest pCR rate reported in the literature was obtained with anthracycline-based regimens in combination with trastuzumab. This study evaluated whether non-anthracycline combination chemotherapy with PGH could improve the pCR rate in HER2 positive BC. Methods: HER2 positive, stage II/III BC pts with cytologically confirmed axillary lymph node (LN), ≥ 18 years of age, with adequate organ function, and good performance status were eligible. No prior therapy was allowed. Pts received H intravenously (iv) at 4 mg/kg on D1 of the first cycle with subsequent weekly doses of 2 mg/kg in combination with P 80 mg/m2 and G 1,200 mg/m2, iv, on D1/D8 every 3 wks for 6 cycles. Within 2 wks postoperatively, patients received H 6 mg/kg every 3 wks for 11 cycles with tamoxifen or an aromatase inhibitor for 5 years if indicated. All pts received postoperative radiation therapy. Initial evaluation included sonogram and MRI of the breast, MUGA scan, or echocardiogram, and PET-CT. Results: All 53 planned pts were enrolled between April 2007 and February 2008. The median age was 43 years (range, 26–61 years), the median primary tumor size by sonogram was 5.3 cm (range, 2.0 to &gt; 12 cm) with 89 % ≥ stage IIIA, 42% T3/T4, and 28% N3. Twenty four tumors (45%) were multiple and 20 tumors (38%) were ER positive. By May 2008, 47 patients completed surgery with a 74% breast conservation rate. Twenty-eight of 47 (60%; 95% CI, 45-72) patients achieved pCR in both the tumor and lymph node, with 68% (32/47; 95% CI, 54-80) pCR in the primary tumor, and 77% (36/47; 95% CI, 63-86) pCR in the axillary LN. Median metastatic focus in 21 positive LNs (n=11 pts) was 1 mm (range, &lt;1–13mm). Grade III/IV adverse events (AE) were neutropenia (53%), febrile neutropenia (4%), and transient elevation of AST/ALT (9%). After 6 cycles of PGH chemotherapy, all patients maintained above normal LVEF. Conclusions: A remarkably high pCR was obtained by non-anthracyline based PGH combination therapy for HER2 positive stage II/III breast cancer. This combination is well tolerated with mild degree of AEs.&#x2028; Supported by NCC Grant No 0610240-3. Trastuzumab, paclitaxel, and gemcitabine were supplied by Roche, CJ Cheiljedang CO., and Eli Lilly and CO., respectively.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5105.

Ki-67 gives additional prognostic information on St Gallen 2007 and Adjuvant! Online risk categories in early breast cancer

Abstract #1086

Purpose: We sought to determine the significance of Ki-67, one of the tumor cell proliferation indexes, as a useful prognostic factor in early breast cancer.&#x2028; Patients and Methods: 1,080 consecutive patients with stage I or II breast cancer operated between 1998 and 2003 were enrolled. Patients were categorized based on the 2007 St. Gallen consensus and Adjuvant! Online. The expression of Ki-67 in the tumor was assayed using immunohistochemistry (cut-off value: 10%).&#x2028; Results: Univariate analysis revealed that tumor size, lymph node involvement, histologic grade, estrogen receptor, progesterone receptor, bcl-2, and Ki-67 (≥10%) were significant for both overall survival (OS) and distant metastasis-free survival (DFS). Of them, lymph node involvement and high Ki-67 expression were identified as independent prognostic factors for OS at multivariate analysis. The survivals of intermediate- and high-risk groups according to 2007 St Gallen consensus were further separated by Ki-67 expression level (5-yr DFS rate=93.3% vs 86.6% for Ki-67&lt;10% and ≥10%, respectively in intermediate-risk group (p=.001); 5-yr DFS rate=83.1% vs 61.5% for Ki-67&lt;10% and ≥10%, respectively in high-risk group (p=.006)). The survivals of low- and high-risk groups according to Adjuvant! Online were further separated by Ki-67 expression level [5-yr DFS rate=97.8% vs 89.5% for Ki-67&lt;10% and ≥10%, respectively in low-risk group (p=.010); 5-yr DFS rate=90.4% vs 82.6% for Ki-67&lt;10% and ≥10% in high-risk group (p=.005)).&#x2028; Conclusion: Ki-67 was an independent prognostic factor for DFS and OS in early breast cancer, and could give additional prognostic information on the risk grouping by 2007 St Gallen consensus and Adjuvant! Online.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1086.

Comparable efficacies between premenopausal and postmenopausal metastatic breast cancer patients by letrozole with and without goserelin as first line hormone therapy: a phase II parallel group study

Abstract #6134

Background: The use of goserelin in premenopausal patients(pts) is to produce castrated level of estradiol (E2), and the remaining peripheral E2 production is inhibited by letrozole, which would accomplish comparable clinical outcomes as in postmenopausal metastatic breast cancer (MBC) pts by letrozole alone.&#x2028; Methods: Hormone receptor positive pre- and postmenopausal pts with MBC were eligible. Letrozole 2.5 mg once a day was administered with goserelin 3.6 mg every 4 weeks in premenopausal pts and serial serum E2, FSH, LH were measured. Bone mineral density (BMD) and serum bone turnover markers were also checked (n=34).&#x2028; Results: Among total 78 pts enrolled, 32 pre- and 38 postmenopausal pts were assessed for efficacy and adverse events (AE). The median age was 42 years (range, 32–52) for pre- and 53 years (range, 33–70) for postmenopausal pts. Baseline characteristics were similar in the two groups, except for significantly longer disease free interval in postmenopausal pts (22.2 months vs. 41.2 months, P=0.01). Clinical benefit (CR+ PR+ SD ≥ 24 weeks) rates (62.5% vs. 68.4%, P=0.62), and objective response (CR + PR) rates (28.1 % vs. 23.7%, P=0.79) were comparable between the two groups. Median TTP was 8.6 months vs. 9.6 months (P=0.61) with a median follow-up of 11.6 months and 14.6 months, respectively. In multivariate analysis, strong ER status was significantly associated with clinical benefit rate (P=0.01), and HER2 positivity (P&lt;0.001) and stage IV presentation (P=0.05) with shorter TTP. In premenopausal pts, the mean E2 level was dropped from 62.3 ± 81.8 pg/mL at baseline to 12.3 ± 2.2 pg/mL at week 2. AEs were mild with significantly more hot flushes in premenopausal pts. In premenopausal pts without bisphosphonate treatment, there was a trend of rising serum levels of osteocalcin (OC) (0% vs. 165%, P=0.065), bone alkaline phosphatase (bALP) (0% vs. 28%, P=0.055), and C-telopeptide (CTx) (0% vs. 108%, P=0.095), as well as a significant reduction in both lumbar spine (P=0.044) and femur (P=0.027) BMD. In contrast, in premenopausal pts with bone metastasis on bisphosphonate, there was no significant change in OC, bALP, CTx, and both BMD. In postmenopausal pts without bisphosphonate treatment, no significant change in OC, bALP, CTx, and femur BMD, while in pts with bone metastasis on bisphosphonate treatment, a significant decrease in OC (0% vs. -22%, P=0.050) and CTx (0% vs. -41%, P=0.020) and increase in both BMD (P=0.044, P=0.038 respectively) were observed.&#x2028; Conclusions: Clinical efficacies by letrozole and goserelin therapy in premenopausal MBC pts were comparable to those in postmenopausal pts by letrozole with mild AEs. While a modest increase in both bone formation and resorption especially in premenopausal pts, concurrent bisphosphonate therapy could stabilize bone metabolism in patients even with bone metastasis.&#x2028; Supported by NCC Grant No NCS-0610240-3. Letrozole for premenopausal group was supplied by Novartis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6134.

Does triple-negative breast cancer (TNBC) have distinct clinicopathologic characteristics and prognostic significance?

21088

Background: Studies have suggested that TNBC, defined by estrogen receptor-negative, progesterone receptor-negative, and HER2-negative, may represent the subset of breast cancer(BC) with different biologic behavior. Here we investigated the clinicopathologic characteristics of TNBC and its prognostic significance in Korean BC patients. Methods: Patients diagnosed as invasive BC and underwent curative surgery at Seoul National University Hospital between Jan. 2000 and Jun. 2003, were reviewed, retrospectively. We excluded the patients whose immunohistochemistry for hormone receptor nor HER2 status had not been evaluated, and who had been treated with adjuvant trastuzumab or neoadjuvant chemotherapy (CT). Clinicopathologic variables (age, T and N stage, endovascular or lymphatic tumor emboli, nuclear and histologic grade, p53, bcl2, Ki67) and 3 year relapse free survival (3YRFS) rate of TNBC were compared with those of non- TNBC. Results: 1,136 patients were eligible for analysis. The median follow-up was 48.7 months. 341 patients underwent breast conserving surgery followed by adjuvant radiotherapy. 249 patients were TNBC and 62.1% of those were node negative. 86.4% of node negative TNBC, 88.3% of node positive TNBC, 53.9% of node negative non-TNBC, and 90.2% of node positive non-TNBC received adjuvant CT. Compared with non-TNBC, TNBC was correlated with younger age (age<35,14.1% vs. 8.2%, p=0.013), higher nuclear and histologic grade(62.2% vs. 23.6%, p=0.001;60.2% vs. 24.6%, p=0.001, respectively); positive staining for p53 (p=0.001) and higher positivity for Ki67 (p=0.001), suggesting the biologic aggressiveness of TNBC. During the follow-up periods, 17.3% of TNBC were relapsed. In particular, 3YRFS in node negative TNBC and non-TNBC were 86% and 96%, respectively (p<0.001). But, in node positive BC, 3YRFS was not different between TNBC and non-TNBC (80.6% vs. 83%, p=0.99). Conclusions: We confirm that TNBC shows more aggressive clinicopathologic characteristics and in particular, higher relapse in node negative BC. Thus, triple-negativity(TN) may be integrated into risk factor analysis in node negative BC. Final results of more detailed molecular analysis for TNBC would be available in the meeting.

No significant financial relationships to disclose.

Inductively-coupled control unit for fully implantable middle ear hearing devices

Recently, fully-implantable middle ear hearing devices (F-IMEHD) to enhance the hearing ability of auditory impaired persons have been developed in several countries. The implantable hearing device requires an external controller and a non-invasive power transmitter for recharging an internal battery of the device. This study shows the implementation of an inductively coupled control unit to be able to recharge the battery and transmit a control signal to the implanted device by designing the structure of coupled antennas and the data protocol using an on-off keying modulation. The implemented control unit has the advantages that it makes the implanted device reduce the power consumption and increase a recharging interval by externally supplying the power of a control signal receiver instead of using an internal battery. Through the experimental results, it has been verified that the implemented control unit has the performance of transmitting power and control signal to a F-IMEHD.

Implementation of a transcutaneous charger for fully implantable middle ear hearing device

A transcutaneous charger for the fully implantable middle ear hearing device (F-IMEHD), which can monitor the charging level of battery, has been designed and implemented. In order to recharge the battery of F-IMEHD, the electromagnetic coupling between primary coil at outer body and secondary coil at inner body has been used. Considering the implant condition of the F-IMEHD, the primary coil and the secondary coil have been designed. Using the resonance of LC tank circuit at each coil, transmission efficiency was increased. Since the primary and the secondary coil are magnetically coupled, the current variation of the primary coil is related with the impedance of internal resonant circuit. Using the principle mentioned above, the implanted module could transmit outward the information about charging state of battery or coupling between two coils by the changing internal impedance. As in the demonstrated results of experiment, the implemented charger has supplied the sufficient operating voltage for the implanted battery within about 10 mm distance. And also, it has been confirmed that the implanted module can transmit information outward by control of internal impedance.

Electromyography as a measure of peak and cumulative workload in intermediate care and its relationship to musculoskeletal injury: an exploratory ergonomic study

Injury rates in Intermediate Care (IC) facilities are high and the factors related to these injuries are unclear. The objectives of this exploratory sub-study, which is part of a large multi-faceted study in 8 IC facilities are to: (1) evaluate EMG measured over a full-shift in the back and shoulders of 32 care aides (CAs) as an indicator of peak and cumulative workload (n = 4 x 8 facilities); investigate the relationship between EMG measures and injury indicators; and explore the relationship between EMG measures and other workload measurements. Lumbar EMG was converted to predicted cumulative spinal compression and ranged in CAs from 11.7 to 22.8 MNs with a mean of 16.4 MNs. Average compression was significantly different during different periods of the day (p < 0.001) with highest compression during pre-breakfast when CAs assist most with activities of daily living. Significant differences were found in average compression between low and high injury facilities for 3 of 5 periods of the day (p < 0.010). Peak compressions exceeding 3400 N occurred for very little of the workday (e.g. 11.25s during the 75 min period pre-breakfast). Peak neck/shoulder muscle activity is low (99% APDF ranged from 8.33% to 28% MVC). Peak and cumulative spinal compression were significantly correlated with lost-time and musculoskeletal injury rates as well as with total tasks observed in the CAs (p < 0.01). Perceived exertion was only correlated with peak compressions (p < 0.01). Facilities with low injury rates provided significantly more CAs (p < 0.01) to meet resident needs, and subsequently CAs performed fewer tasks, resulting in less peak and cumulative spinal loading over the day.

Finite element contact stress analysis of the RPD abutment tooth and periodontal ligament

OBJECTIVES

The purpose of this study was to determine the influence of the occlusal rest position in removable partial dentures on the displacement of the abutment tooth and the stress distribution in the periodontal ligament (PL).

METHODS

We constructed three-dimensional finite element models of the mandibular first and second premolars. A layer of the PL and a mesial or distal occlusal rest were produced on the second premolar as an abutment. A zero displacement was prescribed on the outer surface of the PL and the first premolar. In each simulation, the rest was moved 0.05 mm vertically to the apical direction, with or without restriction of horizontal movements. We simulated the contact phenomena on the abutment surfaces, and calculated the movements of the abutment and stress distributions in the PL.

RESULTS

We observed a maximum distal displacement of 42 microm at the buccal cusp of the abutment and a principal compressive stress of 0.35 MPa in the PL when the abutment was vertically loaded by a distal rest that was allowed to move horizontally. However, the displacements and stresses were relatively small, and were all within the physiological limitations of the tissues. The restriction of the horizontal movement of the rests was effective in reducing the horizontal displacements of the abutment, regardless of the rest position.

CONCLUSIONS

The single vertical load exerted from either the mesial or distal rest on the abutment was unlikely to cause any mechanical damage to its supporting tissues.

Work organization and patient care staff injuries: the impact of different care models for "alternate level of care" patients

BACKGROUND

The number of elderly patients who do not have acute-care needs has increased in many North American hospitals. These alternate level care (ALC) patients are often cognitively impaired or physically dependent. The physical and psychosocial demands on caregivers may be growing with the increased presence of ALC patients leading to greater risk for injury among staff.

METHODS

This prospective cohort study characterized several models for ALC care in four acute-care hospitals in British Columbia, Canada. A cohort of 2,854 patient care staff was identified and followed for 6 months. The association between ALC model of care and type and severity of injury was examined using multinomial and ordinal logistic regression.

RESULTS

Regression models demonstrated that the workers on ALC/medical nursing units with "high" ALC patient loads and specialized geriatric assessment units had the greatest risk for injury and the greatest risk for incurring serious injury. Among staff caring for ALC patients, those on dedicated ALC units had the least risk for injury and the least risk for incurring serious injury.

CONCLUSIONS

The way in which ALC care is organized in hospitals affects the risk and severity of injuries among patient care staff.

Purification, characterization, and molecular cloning of a novel amine:pyruvate transaminase from Vibrio fluvialis JS17

A transaminase from Vibrio fluvialis JS17 showing activity toward chiral amines was purified to homogeneity and its enzymatic properties were characterized. The transaminase showed an apparent molecular mass of 100 kDa as determined by gel filtration chromatography and a subunit mass of 50 kDa by MALDI-TOF mass spectrometry, suggesting a dimeric structure. The enzyme had an isoelectric point of 5.4 and its absorption spectrum exhibited maxima at 320 and 405 nm. The optimal pH and temperature for enzyme activity were 9.2 and 37 degrees C, respectively. Pyruvate and pyridoxal 5'-phosphate increased enzyme stability whereas (S)-alpha-methylbenzylamine reversibly inactivated the enzyme. The transaminase gene was cloned from a V. fluvialis JS17 genomic library. The deduced amino acid sequence (453 residues) showed significant homology with omega-amino acid:pyruvate transaminases (omega-APT) from various bacterial strains (80 identical residues with four omega-APTs). However, of 159 conserved residues in the four omega-APTs, 79 were not conserved in the transaminase from V. fluvialis JS17. Taken together with the sequence homology results, and the lack of activity toward beta-alanine (a typical amino donor for the omega-APT), the results suggest that the transaminase is a novel amine:pyruvate transaminase that has not been reported to date.

Dynamic retentive force of a mandibular unilateral removable partial denture framework with a back-action clasp

PURPOSE

The purpose of this study was to investigate the dynamic retentive force of a mandibular unilateral distal-extension partial denture framework with a back-action clasp that was designed in a buccally tilted cast on a dental surveyor. The retention mechanism of this framework was analyzed in comparison with other typical unilateral and bilateral frameworks for the mandibular Kennedy class II case.

MATERIALS AND METHODS

Experimental gold alloy frameworks of three designs were repositioned to the master cast, and lifted upward to the vertical direction to the occlusal plane. The load required to dislodge each framework was recorded. The retentive force of each framework was determined by the maximum load in a dislodgment cycle. The bending strength of a plain clasp pattern of the same length as the clasp arm used in each framework was also measured by cantilever beam test.

RESULTS

The mean retentive force of the unilateral framework with a back-action clasp of relatively low bending strength was significantly higher (P < 0.01) than that of the unilateral framework with two Akers clasps of relatively high bending strength, and 70 to 80% of the bilateral framework with two Akers clasps on the edentulous side and a double Akers clasp on the contralateral side. The unilateral framework with a back-action clasp showed the greatest early load resistance in the dislodgment cycle among the three designs.

CONCLUSION

The reasonable retention mechanism was demonstrated by the unilateral framework with a back-action clasp.

Identification of a structural motif of 23S rRNA interacting with 5S rRNA

To identify RNA motifs interacting with 5S rRNA, a systematic evolution of ligands by exponential enrichment experiment was applied. Some of the resulting RNA aptamers contained a consensus sequence similar to the sequence in the loop region of helix 89 of 23S rRNA. We show that the synthetic helix 89 RNA motif indeed interacted with 5S rRNA and that the region around loop B of 5S rRNA was involved in this interaction. These results suggest the presence of a novel RNA-RNA interaction between 23S rRNA and 5S rRNA which may play an important role in the ribosome function.

Rat embryo fibroblasts require both the cell-binding and the heparin-binding domains of fibronectin for survival

Fibronectin (FN) is known to transduce signal(s) to rescue cells from detachment-induced apoptosis (anoikis) through an integrin-mediated survival pathway. However, the functions of individual FN domains have not been studied in detail. In the present study we investigated whether the interaction of the cell-binding domain of FN with integrin is sufficient to rescue rat embryo fibroblasts (REFs) from detachment-induced apoptosis. REFs attached and spread normally after plating on substrates coated with either intact FN or a FN fragment, FN120, that contains the cell-binding domain but lacks the C-terminal heparin-binding domain, HepII. REFs on FN maintained a well-spread fibroblastic shape and even proliferated in serum-free medium at 20 h after plating. In contrast, previously well-spread REFs on FN120 started losing fibroblastic shape with time and detached from FN120-coated plates after approx. 8 h. Nuclear condensation indicated apototic cell death. This was due to the decreased activity/stability of focal adhesion kinase (pp125FAK) in the absence of HepII domain. A peptide in the HepII domain [peptide V, WQPPRARI (single-letter amino acid codes)], which has previously been implicated in cytoskeletal organization, rescued apoptotic changes. Consistently, pp125FAK phosphorylation was increased, and both cleavage of pp125FAK and activation of caspase 3 on FN120 were partly blocked by peptide V. Thus the interaction of the cell-binding domain with integrin has a major role in cell survival but is itself not sufficient for cell survival. One or more additional survival signals come from the HepII domain to regulate pp125FAK activity/stability.

Activity of the APC(Cdh1) form of the anaphase-promoting complex persists until S phase and prevents the premature expression of Cdc20p

Cell cycle progression is driven by waves of cyclin expression coupled with regulated protein degradation. An essential step for initiating mitosis is the inactivation of proteolysis mediated by the anaphase-promoting complex/cyclosome (APC/C) bound to its regulator Cdh1p/Hct1p. Yeast APC(Cdh1) was proposed previously to be inactivated at Start by G1 cyclin/cyclin-dependent kinase (CDK). Here, we demonstrate that in a normal cell cycle APC(Cdh1) is inactivated in a graded manner and is not extinguished until S phase. Complete inactivation of APC(Cdh1) requires S phase cyclins. Further, persistent APC(Cdh1) activity throughout G1 helps to ensure the proper timing of Cdc20p expression. This suggests that S phase cyclins have an important role in allowing the accumulation of mitotic cyclins and further suggests a regulatory loop among S phase cyclins, APC(Cdh1), and APC(Cdc20).

Five cases of ocular toxocariasis confirmed by serology

We report 5 cases of ocular toxocariasis in Korean adults complaining of visual impairment along with floating or bubbling sensation. Fundoscopic examination revealed a retinal detachment along with exudate in 4 cases. They all showed typical reaction by ELISA and immunoblot against Toxocra excretory-secretory antigen. One case showed high level of anti-Toxocara IgE antibodies (34,000 Toxocara units/L) as well as increased level of serum total IgE antibodies and the specific IgE antibodies for 3 inhalant antigens, suggesting that high level of anti-Toxocara IgE antibodies was associated with an atopic status. Clinical manifestations were improved after the sequential use of steroids then mebendazole. We also suggest that ocular toxocariasis should be thoroughly investigated even when an evocative uniocular inflammatory lesion is encountered in peripheral retina without a systematic disease.

Tumor suppressor p53 is required to modulate BRCA1 expression

Individuals carrying mutations in BRCA1 or p53 genes are predisposed to a variety of cancers, and both tumor suppressor genes have been implicated in DNA damage response pathways. We have analyzed a possible functional link between p53 and BRCA1 genes. Here we show that BRCA1 expression levels are down-regulated in response to p53 induction in cells that undergo either growth arrest, senescence, or apoptosis. Physiological stimuli, such as exposure to DNA-damaging agents, also result in negative regulation of BRCA1 levels in a p53-dependent manner prior to causing cell cycle arrest. Nuclear run-on experiments and luciferase reporter assays demonstrate that the changes in BRCA1 expression are mainly due to transcriptional repression induced by p53. In conclusion, the data show that BRCA1 expression levels are controlled by the presence and activity of wild-type p53 and suggest the existence of an intracellular p53/BRCA1 pathway in the response of cells to stress conditions.