A Computer Controlled Scanning Transmission Electron Microscope Equipped with an Energy Analyzer for Special Investigations on Electron Diffraction- and Channeling Patterns

A scanning electron microscope was equipped with a double tilting stage, driven by stepping motors, to investigate electron channeling patterns (ECPs) and large angle convergent beam patterns (LACBPs) of single crystals. Transmitted electrons may be energy-selected by a magnetic sector-field energy analyzer. The recording of experimental data and the experimental arrangement are controlled by a microprocessor system, including a picture storage unit of 512 x 512 pixels of 16 bit. Recorded patterns can be stored on 1 Megabyte floppies. A set of useful programs allows one to perform calculations with stored patter ns, e.g., contrast enhancement or -inversion, noise reduction, difference or quotient of two patterns etc. The possibility of background subtraction (e.g., in patterns recorded with characteristic energy loss electrons) allows one to get true K-loss convergent beam patterns. Other recording modes allow one to get two CBPs simultaneously recorded with electrons of different energy losses, to measure angle dependences of energy selected electrons, or to take electron energy loss spectra. A special processor program generates a theoretically calculated CBP or ECP on the TV screen and prints out a list of all band edges up to a chosen limit of Miller indices (hkl). The program requires the coordinates of two known poles and some crystallographic properties of the investigated material. Thus complete indexing of recorded diffraction patterns is easily possible. The system has been applied, e.g., to investigate localization effects of electron Bloch-waves in graphite

Ki67, chemotherapy response, and prognosis in breast cancer patients receiving neoadjuvant treatment

<p>Abstract</p> <p>Background</p> <p>The pathological complete response (pCR) after neoadjuvant chemotherapy is a surrogate marker for a favorable prognosis in breast cancer patients. Factors capable of predicting a pCR, such as the proliferation marker Ki67, may therefore help improve our understanding of the drug response and its effect on the prognosis. This study investigated the predictive and prognostic value of Ki67 in patients with invasive breast cancer receiving neoadjuvant treatment for breast cancer.</p> <p>Methods</p> <p>Ki67 was stained routinely from core biopsies in 552 patients directly after the fixation and embedding process. HER2/neu, estrogen and progesterone receptors, and grading were also assessed before treatment. These data were used to construct univariate and multivariate models for predicting pCR and prognosis. The tumors were also classified by molecular phenotype to identify subgroups in which predicting pCR and prognosis with Ki67 might be feasible.</p> <p>Results</p> <p>Using a cut-off value of > 13% positively stained cancer cells, Ki67 was found to be an independent predictor for pCR (OR 3.5; 95% CI, 1.4, 10.1) and for overall survival (HR 8.1; 95% CI, 3.3 to 20.4) and distant disease-free survival (HR 3.2; 95% CI, 1.8 to 5.9). The mean Ki67 value was 50.6 ± 23.4% in patients with pCR. Patients without a pCR had an average of 26.7 ± 22.9% positively stained cancer cells.</p> <p>Conclusions</p> <p>Ki67 has predictive and prognostic value and is a feasible marker for clinical practice. It independently improved the prediction of treatment response and prognosis in a group of breast cancer patients receiving neoadjuvant treatment. As mean Ki67 values in patients with a pCR were very high, cut-off values in a high range above which the prognosis may be better than in patients with lower Ki67 values may be hypothesized. Larger studies will be needed in order to investigate these findings further.</p

Vacuum-assisted breast biopsy: A comparison of 11-gauge and 8-gauge needles in benign breast disease

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