A non-uniform expansion mechanical safety model of the stent

Stents have a serial unstable structure that readily leads to non-uniform expansion. Non-uniform expansion in turn creates a stent safety problem. We explain how a stent may be simplified to a serial unstable structure, and present a method to calculate the non-uniform expansion of the stent on the basis of the serial unstable structure. We propose a safety criterion based on the expansion displacement instead of the strain, and explain that the parameter Rd, the ratio of the maximum displacement of the elements to normal displacement, is meaningful to assess the safety level of the stent. We also examine how laser cutting influences non-uniform expansion. The examples illustrate how to calculate the parameter Rd to assess non-uniform expansion of the stent, and demonstrate how the laser cutting offset and strengthening coefficient of the material influence the stent expansion behaviour. The methods are valuable for assessing stent safety due to non-uniform expansion.

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.

Genetic evolution of EGFR and the clonal origin of adenocarcinomas exhibiting various degrees of bronchioloalveolar carcinoma

e22050

Background: EGFR mutations may accumulate during multistage progression of bronchioloalveolar carcinoma (BAC), leading to heterogeneity within the tumor. Moreover, intrapulmonary emersions are the predominant sites of BAC progression in the absence of other distant metastases. In cases of emerging bilateral lung lesions during the follow-up to complete resection, the issue of how to differentiate between lesions originating from multifocal BACs or distant metastases/local recurrence is an important and unresolved issue. This study was performed to determine whether sequential adenocarcinoma with BAC features emerges in the lung field arises from a single clone or multiple clones in the same individual. Methods: Samples of adenocarcinomas exhibiting various degrees of BAC were obtained by thoracotomy. Sequential specimens were obtained on detection of novel lesions in the lung field. Genomic DNA was extracted from the specimens, and the presence of activating mutations in EGFR was analyzed by direct sequencing. Our pathological findings, sequential imaging, and EGFR sequence data were compared to monitor evidence of cancer evolution. Results: Based on an analysis of EGFR in tumor specimens from 428 lung cancer patients, fifteen cases of sequential BAC-related adenocarcinoma obtained by thoracotomy were identified. Together with alterations in BAC/adenocarcinoma components, the EGFR-TKI untreated series with at least one episode of EGFR-activating mutations represented three typical models: no significant EGFR evolution for a single clone, genetic alterations from mutant to wild-type EGFR for multifocal lesions, and a switch from wild-type to mutant EGFR, which might exhibit uncertain circumstances of cancer progression. Conclusions: Genetic analysis in conjunction with pathological and radiological diagnoses can be used to explore the origin of multifocal BAC. The single clone model indicates subsequent disease progression, whereas genetic alterations from mutations to wild-type EGFR are suggestive of secondary primary carcinoma. When additional lesions emerge after radical resection of BAC-related lung cancer, sequential tumor samples should be obtained for further evaluation.

No significant financial relationships to disclose.

Detection of human papillomavirus DNA from the breast carcinomas and the cervix: Are they correlated?

1544

Background: The association between human papillomavirus (HPV) and cervical cancer is well known. However, it remains unclear whether there is also a correlation between HPV infection and human breast cancer. The aim of this study is to investigate the hypothetic association between HPV infection and breast carcinoma through the comparison of the type of HPV infection in the breast and cervix. Methods: From April to December 2008, 106 patients who were diagnosed as breast cancer and underwent mastectomy were analyzed. Their breast tissue (tumor, normal parenchyme, and nipple-areolar complex) and cervix smear were analyzed for HPV infection with DNA chip microarray method. Results: 24 patients (23.1%) showed HPV infection in their cervix smear; high-risk type of HPV was found in 12 patients. But only six patients (5.8%) revealed the HPV infection in breast cancer; half of them were high-risk group (HPV-16, 31); the same types of HPV was found at the normal breast tissue in two patients of them. However, there were no patients with HPV infection in both breast and cervix concurrently. Conclusions: There were no positive results for HPV infection of cervix in HPV-infected breast cancer patients. Also, we cannot find that the presence of high-risk HPV in the breast might be related to the breast carcinogenesis. We concluded that HPV infection is not correlated to the carcinogenesis of breast.

No significant financial relationships to disclose.

Prognostic impact of polymorphisms of caspase genes on survival in patients with operated invasive ductal breast cancer

e22020

Background: Since the apoptosis induced by caspases may play a role in the prognosis of breast cancer, the present study analyzed the polymorphisms of caspase genes and their impact on the survival in patients with operated invasive ductal breast cancer. Methods: Two hundred eighty patients with breast cancer who underwent surgery with curative intent were enrolled in the present study. The genomic DNA was extracted from paraffin-embedded tissue, and 7 single nucleotide polymorphisms (SNPs) of 6 caspase genes were determined using a PCR-RFLP assay. Results: The median age was 49 (range, 24–82) years, and 157 (56.1%) patients were premenopause at the time of diagnosis. Thirty-six (12.9%) patients underwent breast-conserving surgery. Pathologic stages after surgery were as follows: stage I (n=86, 30.7%), stage II (n=129, 46.1%), and stage III (n=63, 22.5%). Among the target SNPs, CASP6 (rs2301717, +5095G>T) and CASP7 (rs11593766, +11G>T) were found to correlate with relapse-free survival (RFS) after curative surgery in an univariate analysis adjusted to age, stage, histological grade, and the immunohistochemical expression of estrogen receptor and HER2. Meanwhile, multivariate analysis showed that the combined GT and TT genotype of CASP6 (rs2301717) was associated with a better RFS than the GG genotype (HR=0.39; 95% CI=0.19–0.79; p=0.009). However, there was no significant association with overall survival. Conclusions: The CASP6 (rs2301717) polymorphism may be considered as a possible prognostic factor for survival in patients with operated invasive breast cancer.

No significant financial relationships to disclose.

Triple detection method for sentinel lymph node detection

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Background: Sentinel lymph node biopsy is widely accepted method to determine nodal stage of breast cancer. There are several reported method for detecting sentinel lymph node. The aim of this study was to show the new detection method of sentinel lymph node and show the effectiveness of this method. Methods: We did prospective study and enrolled 25 patients who underwent partial mastectomy and sentinel lymph node biopsy. We injected indigocyanine green (green dye) at peritumoral lesion, indigocarmine dye (blue dye) in subareolar area and radioisotope (Tc-99m) injection. Sentinel lymph nodes are identified by color change or radioisotope uptake, and classified by each color (blue or green) and radioisotope uptake. We compared the detection rate from our study with that from the previous studies. Results: Sentinel lymph nodes were detected in all patients (25/25). Green color stained sentinel lymph nodes were identified in 18 patients (18/25), blue color stained sentinel lymph nodes were identified in 15 patients (15/25) and radioactive lymph nodes were identified in 19 patients (19/25). Conclusions: The triple mapping method showed higher detection rate than the previous studies and this method is recommendable to detect sentinel lymph node.

No significant financial relationships to disclose.

Risk stratification by hormonal receptor (ER, PgR) and HER2 status in small (≤1cm) invasive breast cancer: Who might be a possible candidate for adjuvant treatment?

564

Background: With the increasing use of screening mammography, the proportion of ≤ 1 cm invasive breast cancer is increasing. Identification of breast cancer molecular subtypes has resulted in a better appreciation of the biologic heterogeneity, which is not fully explained by clinicopathologic features including staging system. The aims of this study were: 1) to identify the risk factors of systemic metastases in patients with ≤ 1 cm invasive breast cancer and 2) to investigate the patients group at greatest risk of such failure even in these small tumors. Method: Data were collected retrospectively in the breast cancer registry of our institution for patients with invasive breast cancer from October 1994 to December 2004. Results: Of 4,036 patients who received curative breast cancer surgery, 466 patients who had T1a or T1b breast cancer were identified. 39 patients who received neoadjuvant chemotherapy were excluded in this study. Ipsilateral axillary lymph node involvement was found in 13% (57/427) at the time of surgery. Axillary lymph node involvement was much more common in HER-2 positive group (33% vs 11%, p < 0.0001) and triple negative (TN) group (24% vs 11%, p = 0.002) than in hormone receptor positive group. During median 61 months of follow-up, overall 10 year estimated distant relapse-free survival (DRFS) and overall survival (OS) were 95% and 92%, respectively. Multivariate analysis was conducted in 370 (T1aN0, T1bN0) patients, who had no lymph node involvement. In Cox-regression model, HER-2 positivity and triple negativity were identified as independent prognostic factors to predict DRFS [Hazard ratio (HR) 8.8, p = 0.003 for HER-2 positive group; HR 5.1, p = 0.026 for TN group] and OS (HR 5.0, p = 0.067 for HER-2 positive group; HR 11.1, p = 0.017 for TN group) in T1bN0 tumors. Limiting to T1aN0 tumors, statistical significance was not maintained. Conclusions: Even though T1aN0 and T1bN0 tumors have been known to have a relative low risk of systemic failure, anti-HER-2 directed therapy for HER-2 positive group and new innovative adjuvant systemic treatment for TN group in patients with T1bN0 tumor should be considered. Prospective adjuvant trials should be warranted in these subgroups of patients.

No significant financial relationships to disclose.

HMPS (2-hydroxy-4-methoxyphenylstilbene), a stilbene derivative of rhapontigenin, and cell death by mitochondrial apoptotic pathway in breast cancer cells

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Background: Breast cancer with resistance to clinical therapy is a significant threat to live of recurrent breast cancer patients, and chemo-resistant breast cancer is increasing rapidly. During last several decades, natural stilbenoids have been studied on anticancer effects in vitro and in vivo, and resveratrol is the most famous stilbene as a leading compound in the studies of anticancer compounds derived from plants. HMPS (2-hydroxy-4-methoxyphenylstilbene) is an analogue derived from rhapontigenin (3,5,3'-trihydroxy-4'-methoxy-trans-stilbene), which is a stilbene of herbal plant Rheum undulatum. TMS (2,3',4,5'-tetramethoxystilbene), an another stilbene analogue from rhapontigenin, was reported potent anticancer effect on tamoxifen-resistant MCF-7 cells. In this study we investigated inhibitory effect of HMPS on proliferation of breast cancer and a potential for a new therapeutic candidate. Methods: We examined cell viability of MCF-7 and MDA-MB-231 by MTT assay after exposure to various concentrations of HMPS. Apoptotic cell death induced by HMPS was investigated by florescence microscopy, cell cycle analysis and western blotting. Results: Cell viability of breast cancer cells after 24 h exposure to HMPS decreased significantly, and both ER-positive and ER-negative breast cancer cells responded to HMPS. HMPS induced nucleus fragmentation and G2/M arrest followed by sub-G1 accumulation of apoptotic cells in time- and dose-dependent manner. During the process of cell death induced by HMPS, mitochondrial membrane potential was disturbed and caspase-3 and PARP cleavage were observed. Moreover, HMPS decreased cell number of LTED MCF-7 cells(Long term estradiol deprived cell) effectively. Conclusions: Our results demonstrates that proliferation inhibitory effect of HMPS is about 50-fold more potent than those of rhapontigenin and furthermore HMPS also inhibits cell growth of LTED cells which are difficult to treat therapeutic agents. Therefore, HMPS may be a potential therapeutic candidate to treat the recurrent breast cancer by alone or combination with other conventional anticancer agents.

No significant financial relationships to disclose.

Increased phonon scattering by nanograins and point defects in nanostructured silicon with a low concentration of germanium

The mechanism for phonon scattering by nanostructures and by point defects in nanostructured silicon (Si) and the silicon germanium (Ge) alloy and their thermoelectric properties are investigated. We found that the thermal conductivity is reduced by a factor of 10 in nanostructured Si in comparison with bulk crystalline Si. However, nanosize interfaces are not as effective as point defects in scattering phonons with wavelengths shorter than 1 nm. We further found that a 5 at. % Ge replacing Si is very efficient in scattering phonons shorter than 1 nm, resulting in a further thermal conductivity reduction by a factor of 2, thereby leading to a thermoelectric figure of merit 0.95 for Si95Ge5, similar to that of large grained Si80Ge20 alloys.

Optical spectroscopy of superconducting Ba0.55K0.45Fe2As2: evidence for strong coupling to low-energy bosons

Normal state optical spectroscopy on single crystals of the new iron arsenide superconductor Ba0.55K0.45Fe2As2 shows that the infrared spectrum consists of two major components: a strong metallic Drude band and a well-separated midinfrared absorption centered at 0.7 eV. It is difficult to separate the two components unambiguously but several fits using Lorentzian peaks suggest a model with a Drude peak having a plasma frequency of 1.6 to 2.1 eV and a midinfrared peak with a plasma frequency of 2.5 eV. Detailed analysis of the frequency dependent scattering rate shows that the charge carriers interact with a broad bosonic spectrum extending beyond 100 meV with a very large coupling constant lambda=3.4 at low temperature. As the temperature increases this coupling weakens to lambda=0.78 at ambient temperature. This suggests a bosonic spectrum that is similar to what is seen in the lower Tc cuprates.

Mechanisms that limit the light stimulus frequency following through the DL-2-amino-4-phosphonobutyric acid sensitive and insensitive rod Off-pathways

In the retina, rod signal pathways process scotopic visual information. Light decrements are mediated by two distinct groups of rod pathways in the dark-adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist dl-2-amino-4-phosphonobutyric acid (APB). We have found that the APB sensitive and insensitive rod Off-pathways signal different light decrement information: the APB sensitive rod Off-pathway conveys slow and low frequency light signals, whereas the APB insensitive rod Off-pathways mediate fast and high frequency light signals [Wang GY (2006) Unique functional properties of the APB sensitive and insensitive rod pathways signaling light decrements in mouse retinal ganglion cells. Vis Neurosci 23:127-135]. However, the mechanisms which limit the frequency following through the APB sensitive and insensitive rod Off-pathways remain unknown. In the current study, whole-cell patch-clamp recordings were made from ganglion cells in dark and light adapted mouse retina to identify the mechanisms that limit the frequency following through the APB sensitive and insensitive rod Off-pathways. The results showed that the sites from AII amacrine cells to Off cone bipolar cells are the major mechanisms that limit the frequency following through the APB sensitive rod Off-pathway. In the APB insensitive rod Off-pathways, rods themselves limited the frequency following through these pathways. Moreover, ganglion cells were able to follow higher frequencies under photopic conditions than under scotopic conditions. The Off responses followed lower frequencies than On responses under photopic conditions. This finding was observed in cells that yielded On or Off responses only as well as in On-Off cells.

Coiled-Coil Hydrogels. Effect of Grafted Copolymer Composition and Cyclization on Gelation

A mean-field theoretical approach was developed to model gelation of solutions of hydrophilic polymers with grafted peptide motifs capable of forming associates of coiled-coil type. The model addresses the competition between associates engaged in branching and cyclization. It results in relative concentrations of intra- and intermolecular associates in dependence on associate strength and motif concentration. The cyclization probability is derived from the model of equivalent Gaussian chain and takes into account all possible paths connecting the interacting motifs. Examination of the association-dissociation equilibria, controlled by the equilibrium constant for association taken as input information, determines the fractions of inter- and intramolecularly associated motifs. The gelation model is based on the statistical theory of branching processes and in combination with the cyclization model predicts the critical concentration delimiting the regions of gelled and liquid states of the system. A comparison between predictions of the model and experimental data available for aqueous solutions of poly[N-(2-hydroxypropyl)methacrylamide] grafted with oppositely charged pentaheptad peptides, CCE and CCK, indicates that the association constant of grafted motifs by four orders of magnitude lower than that of free motifs. It is predicted that at the critical concentration of each motif of about 6×10(-7) mol/cm(3), about half of motifs in associated state is engaged in intramolecular bonds.