Nd:YAG laser penetration into cast titanium and gold alloy with different surface preparations

This study investigated the effect of surface preparation on the Nd:YAG laser penetration into cast titanium and gold alloy. Cast blocks of each metal were given four different surface preparations: (i) coloured with black marker; (ii) air-abraded with 50 microm Al2O3; (iii) ground with SiC points and (iv) polished with 1 microm Al2O3 (mirror-polished). Two blocks with each of the surface preparations were abutted and laser-welded at their interface using the voltages of 210-260 V in increments of 10 V. After the welded blocks were mechanically separated, the laser penetration was measured using computer graphics. Regardless of the surface preparation, an increase in voltage increased the laser penetration for both metals. The laser penetration into titanium prepared with black marker and air-abrasion was significantly deeper than into the titanium ground with SiC points and mirror-polished. Although there were no statistical differences in penetration among the surface preparations for the gold alloy, the penetration in the mirror-polished specimens was shallower than any of the other preparation methods at higher voltages of 240-260 V. The results obtained in this study suggested that broken metal frameworks with finished surfaces should be painted with black marker or air-abraded before laser welding.

Autoantibody against beta1-adrenergic receptor and left ventricular remodeling changes in response to metoprolol treatment

Autoantibodies specific for the beta(1)-adrenoceptor (beta(1)-AR) have been implicated in the pathology of congestive heart failure (CHF). We hypothesized that the presence of autoantibodies against beta(1)-AR (anti-beta(1)-AR) is associated with left ventricular (LV) remodelling in response to metoprolol. Synthetic beta(1)-AR peptides served as the target antigen in an ELISA (enzyme-linked immunosorbent assay) were used to screen the sera of 106 CHF patients. Patients were separated into positive (+) anti-beta(1)-AR or negative (-) anti-beta(1)-AR groups according to their anti-beta(1)-AR reactivity. Echocardiography (ECG) was performed at baseline and after one year of metoprolol therapy in combination with standard treatment regime for CHF, that is, digoxin, diuretics and an ACEI (angiotensin-converting enzyme inhibitor). The dose of metoprolol was doubled on a biweekly basis up to 50 mg x 2 daily (b.i.d./day) or attainment of maximum tolerated dose. Ninety-six patients completed final data analysis. Fifty-four patients with (+) anti-beta(1)-AR had greater improvements than 42 patients with (-) anti-beta(1)-AR in LVEDD (left ventricular end-diastolic dimension) (P < 0.01, from 69 +/- 0.8 to 58.0 +/- 0.5 mm vs. 69.0 +/- 0.8-63.6 +/- 0.9 mm) and LVESD (left ventricular end-systolic dimension) (P < 0.01, from 57.1 +/- 1.4 to 43.9 +/- 0.8 mm vs. 56.2 +/- 0.9-48.6 +/- 1.0 mm), and LVEF (left ventricular ejection fraction) (P < 0.01, from 35.4 +/- 1.3 to 49.8 +/- 0.6% vs. 34.4 +/- 1.0-44.3 +/- 1.1%) by metoprolol therapy in combination with standard treatment regime for one year. Of the CHF patients with (+) anti-beta(1)-AR, 65.4% responded to target metoprolol dose as compared to 21.4% of CHF patients without anti-beta(1)-AR (P < 0.01). Response to target metoprolol dose occurred more rapidly in (+) anti-beta(1)-AR than (-) anti-beta(1)-AR of CHF patients (67.5 +/- 2.4 vs. 100.8 +/- 3.0 days, P < 0.01). These results demonstrated that CHF patients with (+) anti-beta(1)-AR had greater improvements in LV remodelling and heart function by metoprolol as compared to (-) anti-beta(1)-AR patients. Moreover, patients with (+) anti-beta(1)-AR have better tolerance to metoprolol therapy than patients without anti-beta(1)-AR.

Suppression of EGFR expression by antisense or small interference RNA inhibits U251 glioma cell growth in vitro and in vivo

Epidermal growth factor receptor (EGFR) had been reported as one of the major responsible genes for malignant progression and phenotype reversion of gliomas, and has been used as one of the most important therapeutic targets. In the present study, small interference RNA (siRNA) and antisense EGFR expression constructs, which target sequences of human EGFR catalytic domain (2400-2420) and the 3'-coding region, respectively, were used to examine the growth inhibition effects on U251 glioma cells. Cell growth was significantly inhibited and G2/M arrest was observed in antisense- and siRNA-treated groups. Matrigel matrix demonstrated spotted cell clustering pattern in antisense- and siRNA-transfected U251 cells, indicating poor cell growth activities. In addition, the tumor volumes in U251 subcutaneous mice model treated with antisense and siRNA were significantly smaller than those treated with control siRNA and phosphate-buffered saline. Also, glial fibrillary acidic protein expression was upregulated in antisense- and siRNA-treated groups than the control groups. Our results demonstrated that antisense- or siRNA-targeting intracellular region of EGFR can inhibit EGFR expression, exerted growth inhibition effect on U251 glioma cells in vitro and in vivo. Consequently, siRNA expression plasmid-mediated gene therapy would be a new strategy in treatment of gliomas.

High level analysis of genomic data reveals complex predictors of response to trastuzumab (T) and chemotherapy for early stage breast cancer

544

Background: Trastuzumab (T) with chemotherapy has been shown to improve survival in breast cancer patients but de novo resistance is common. Identifying predictors of response to T in primary cancers may lead to an understanding of mechanisms of resistance. We investigated whether combined microarray datasets from patients with early breast cancer treated with preoperative T and chemotherapy could predict for response to therapy. Methods: Two cohorts of patients with HER2 3+/FISH+, stage II-III breast cancer were included in this analysis: trial 1- T and docetaxel (n=38), trial 2 -T and vinorelbine (n=48), both for 12 weeks. Frozen tissue core biopsies were available and successfully amplified in 41 patients (trial 1: 20, trial 2: 21 patients), with standard sample processing, RNA extraction, amplification and hybridization to Affymetrix U133 chips. Differential expression of genes and chromosomal regions, (defined as >10 genes in a given chromosomal cytoband), between patients with pathologic complete response (pCR) vs. those with residual invasive disease were examined. A measure of total functional aneuploidy (tFA) was calculated by summing net deviation in expression of all chromosomal regions and a gene expression signature of genomic instability (CIN) was derived by the identification of genes showing a high level of correlation with tFA . Results: By unsupervised hierarchical analysis, both datasets interdigitated suggesting no inherent bias. Gene expression patterns of individual genes showed weak associations with pCR. However, distinct statistically significant chromosomal regions, Chr2p23 Chr6q24 Chr7q33 Chr2p2 Chr12q21.31 Chr14q32.2 Chr1p34.2 Chr8q21.3, were associated with pCR to T therapy (p<0.005), and were confirmed in more than 50% samples by SNP analysis. In addition, resistant tumors showed higher levels of the CIN signature (p<0.005). Conclusions: We have shown that gene expression data can be merged and used for discovery predictive chromosomal regions associated T response. In addition, chromosomal instability was associated with T resistance. If validated, these distinct dysregulated chromosomal regions may serve as predictive markers of response to trastuzumab therapy.

[Table: see text]

Enhanced diagnosis in suggested malignant pleural effusion using combined modality of genetic and biochemical tumor markers

17137

Background: Cancer is influenced by oncogenes and tumor suppressor genes. Several tumor markers have been applied clinically in malignancy. A malignant pleural effusion may be an initial presentation of cancer and the presence of malignancy is confirmed by pleural cytology and biopsy. However, other diagnostic modalities are limited and not defined clearly, especially in cases of negative results from traditional diagnostic tool. Here, I investigated p53 and FHIT mutations and microsatellite alterations(MA) in the pleural effusion associated with malignancy(ME). Also, the diagnostic values of CEA, NSE, and CYFRA 21–1 as markers of malignant pleural effusion in lung cancer were assessed together. Methods: The genetic analyses of pleural fluid were done in 40 patients with ME and in the pleural fluid of 17 patients with tuberculous pleurisy(TB) as a control group. Levels of CEA, NSE, and CYFRA 21–1 were measured by immunoassay in the serum and pleural fluid of 34 patients with primary lung cancer and of 16 patients with TB. Results: p53 mutations were detected in 13% of ME and 0% of TB, and FHIT mutations were detected in 18% of ME and 12% of TB. Among 4 microsatellite markers; D3S1234, D3S1285, D9S171, and TP53, loss of heterozygosity(LOH) and microsatellite instability(MI) were observed for each group. MA including LOH and MI in at least one marker was seen 63% of ME cases vs. 35% of TB cases. Patients with lung cancer were found to have significantly higher serum and pleural fluid levels of CEA and CYFRA 21–1 than patients with tuberculous pleurisy. Using cut-off values of 5 ng/ml, 20 ng/ml, and 45 ng/ml for pleural fluid CEA, NSE, and CYFRA 21–1, the sensitivities and specificities were as follows: CEA; 82% and 94%, NSE; 36% and 94%, and CYFRA 21–1; 61% and 81%. A combination of pleural fluid CEA and NSE increased sensitivity and specificity. Conclusions: Although still limited in terms of sensitivity and specificity, this study shows that the determinations of CEA and NSE in pleural fluid enhance diagnostic yield better than all the other combination of tumor markers in malignant pleural effusion, especially in lung cancer and molecular diagnostic strategies including microsatellite alterations are possibly applied for the diagnosis of malignant effusion.

No significant financial relationships to disclose.

A phase II trial of stereotactic radiosurgery boost following surgical resection for solitary brain metastases

1552

Background: At present there is no standard of care for adjuvant therapy following resection of solitary brain metastases. The objective of this study was to determine the local control, survival, patterns of relapse and the incidence of brain injury following a surgery-stereotactic radiosurgery (SRS) combined therapy approach while avoiding upfront whole brain radiation therapy (WBRT). Methods: The eligibility criteria included radiologically proven solitary brain metastases, KPS≥70 and a neurologic function score of 0–2. Following the surgical resection, SRS was delivered to the surgical cavity 4–8 weeks later to a dose of 15–22 Gy in a single fraction using the BrainLAB linear accelerator system. Patients were followed with neurological examination and serial MRI images done every 3 months following the procedure. Results: 25 out of 50 patients needed for the study have been accrued since it opened in August 2004. Four patients have failed locally, with a median time to local failure of 9.5 months. The one year local control at the site of original disease was 35%. Two of the four patients who had local recurrence at the time of relapse also had evidence of leptomeningeal disease. Six additional patients developed new brain metastases, resulting in a 1 year brain relapse free survival of 38% following the combined approach. The median overall survival was 12 months. One patient (4%) developed radiation necrosis that required surgical intervention 6 months following the procedure. Six patients (24%) needed WBRT, two patients (8%) needed further SRS and one patient (4%) needed surgery as salvage following development of new brain lesions with this approach. Conclusions: The preliminary results of surgery-SRS approach appear inferior to surgery-WBRT data for solitary brain metastases in terms of local control and development of new brain metastases. However, relapses can be subsequently managed with WBRT without adversely affecting the overall survival and the morbidity.

No significant financial relationships to disclose.

Adenosine triphosphate-based chemotherapy response assay (ATP-CRA)-guided cisplatin-based two-drug chemotherapy in unresectable non-small cell lung cancer

7118

Background: Heterogeneity of tumor response to chemotherapy is a big obstacle in cancer treatment. The aim of this study was to investigate correlations of ATP-CRA and clinical outcome after ATP-TCA-guided cisplatin-based chemotherapy in unresectable NSCLC. Methods: From Sep. 2003 to Oct. 2005, ATP-CRA was done in tumor tissue specimen obtained from patients with suspected lung malignancy. ATP-CRA tested sensitivities of anticancer drugs used widely in advanced NSCLC such as cisplatin, carboplatin, paclitaxel, docetaxel, gemcitabin, and vinorelbine. The cell death rate was determined by measuring the intracellular ATP levels of untreated controls and drug exposed cells. A sensitive drug was defined as a drug producing 30% or more reduction of ATP compared to untreated controls. Test-guided cisplatin-based two-drug chemotherapy was given to pathologically confirmed NSCLC. Results: 31 patients were enrolled and their median follow-up duration was 13.3 months. Response rate was 48.3%. Median progression-free and overall survivals were 4.4 months and 11.2 months, respectively. Patients were dichotomized into platinum-sensitive (S) and resistant (R) groups. S-group (19) contained cases sensitive to platinum alone (6) or both drugs (13). R-group (12) contained cases sensitive to none (9) or the other drug alone (3). Clinical response rate was higher in S-group (75.0% vs 35.3% in R-group; p = 0.0635). Considering correlations of test results and clinical response, positive/negative predictive values were 64.7% / 75.0% with the predictive accuracy of 69.0%. Although without significant differences in histology, stage, and performance status, S-group had longer progression-free (5.0 vs 2.4 months in R-group; p = 0.056) and overall (21.8 vs 9.7 months in R-group; p = 0.018) survivals. Conclusions: In vitro chemosensitivity test, ATP-CRA results and clinical outcome were correlated well after test-guided cisplatin-based two-drug chemotherapy in unresectable NSCLC, presenting favorable response and survival in platinum-sensitive versus resistant group.

[Table: see text]

Birth and morphological evolution of step bunches under electromigration

We analyze the dynamics of electromigration-induced step bunching in the absence of desorption. We show that, even when the instability occurs at long wavelength, hinting to a smooth morphology, the surface suddenly splits into bunches escorted with wide terraces, in agreement with several observations. As the size of the bunches increases, a nonstandard regime is exhibited, namely, the bunches do not match tangentially to the facet, as would the classical Pokrosvky-Talapov shape dictate. This Letter presents a complete scenario of evolution of bunches from their birth up to their ultimate stage.

Intraocular pressure alterations following intravitreal triamcinolone acetonide

AIMS

To determine the prevalence of intraocular pressure (IOP) alterations following intravitreal injection of triamcinolone acetonide (IVTA) and to assess possible risk factors of IOP elevation in eyes receiving single and/or repeat injections.

METHODS

Retrospective, consecutive case series. 570 consecutive eyes of 536 patients who received a single IVTA injection (4 mg/0.1 ml) and a second set of 43 eyes of 40 patients who received a second injection. Retrospective review of all IVTA cases performed by three vitreoretinal surgeons over a 42 month period beginning in 2000. The main outcome measure was change in IOP defined as absolute value of IOP elevation (5 mm Hg or higher, 10 mm Hg or higher), and percentage of baseline (30% or higher increase from baseline IOP).

RESULTS

Of the 528 eyes receiving single injections, 281 (53.2%) had an IOP elevation; 267 eyes (50.6%) experienced an elevation of IOP of at least 30%, and 245 (45.8%) and 75 (14.2%) eyes had an increase of 5 mm Hg or 10 mm Hg or more, respectively. Baseline IOP greater than 16 mm Hg is a risk factor for post-injection IOP elevation. Of the 43 eyes which received a second injection, 28 (65.1%) experienced an increase in IOP of at least 30% of baseline. Filtering surgery was required in five (0.094%) of the single and one (2.3%) of repeat injection eyes.

CONCLUSIONS

Elevated IOP after IVTA is common and patients should be monitored beyond 6 months post-injection. Patients with a baseline IOP more than 16 mm Hg or receiving a second injection should be carefully monitored for an elevated IOP.

Patterning to enhance activity of cultured neuronal networks

Embryonic rat hippocampal neurons were cultured in order to gain insights into how small networks of neurons interact. The principal observations are the electrical activities recorded with the electrode arrays, primarily action potentials both spontaneous and evoked. Several lithographic techniques were developed for controlling with micrometer precision the patterns of surface molecules in order to control neuronal attachment and growth. Cytophilic polylysine against protein repellent and hence cytophobic polyethylene glycol were used. By combining the cellular lithography with the microelectrode arrays it was possible to guide neurons preferentially to electrodes and to begin to investigate the question as to whether the geometric pattern of a neuronal network influences the patterns of its neuroelectric activity. It is clear that the techniques are adequate to ensure contact of neurons to electrodes but not to ensure the recording of signals, even when neurons lie directly on top of electrodes. The maturation of neuroelectric activity depends on the growth of glia within the culture, such that spontaneous activity appears to become robust when the number of glia is roughly the same as the number of neurons.

Decontamination assessment of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surfaces using a hydrogen peroxide gas generator

AIMS

To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas.

METHODS AND RESULTS

Bacillus anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to > or =1000 ppm hydrogen peroxide gas for 20 min. Hydrogen peroxide exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials except G. stearothermophilus on industrial carpet. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with both surrogates. The effectiveness of gaseous hydrogen peroxide on the growth of biological indicators and spore strips was evaluated in parallel as a qualitative assessment of decontamination. At 1 and 7 days postexposure, decontaminated biological indicators and spore strips exhibited no growth, while the nondecontaminated samples displayed growth.

CONCLUSIONS

Significant differences in decontamination efficacy of hydrogen peroxide gas on porous and nonporous surfaces were observed when comparing the mean log reduction in B. anthracis spores with B. subtilis and G. stearothermophilus spores.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results provide comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using hydrogen peroxide gas.