University of Amsterdam

About: University of Amsterdam is a education organization based out in Amsterdam, Noord-Holland, Netherlands. It is known for research contribution in the topics: Population & Randomized controlled trial. The organization has 59309 authors who have published 140894 publications receiving 5984137 citations. The organization is also known as: UvA & Universiteit van Amsterdam.

Cell wall construction in Saccharomyces cerevisiae.

Abstract: In this review, we discuss new insights in cell wall architecture and cell wall construction in the ascomycetous yeast Saccharomyces cerevisiae. Transcriptional profiling studies combined with biochemical work have provided ample evidence that the cell wall is a highly adaptable organelle. In particular, the protein population that is anchored to the stress-bearing polysaccharides of the cell wall, and forms the interface with the outside world, is highly diverse. This diversity is believed to play an important role in adaptation of the cell to environmental conditions, in growth mode and in survival. Cell wall construction is tightly controlled and strictly coordinated with progression of the cell cycle. This is reflected in the usage of specific cell wall proteins during consecutive phases of the cell cycle and in the recent discovery of a cell wall integrity checkpoint. When the cell is challenged with stress conditions that affect the cell wall, a specific transcriptional response is observed that includes the general stress response, the cell wall integrity pathway and the calcineurin pathway. This salvage mechanism includes increased expression of putative cell wall assemblases and some potential cross-linking cell wall proteins, and crucial changes in cell wall architecture. We discuss some more enzymes involved in cell wall construction and also potential inhibitors of these enzymes. Finally, we use both biochemical and genomic data to infer that the architectural principles used by S. cerevisiae to build its cell wall are also used by many other ascomycetous yeasts and also by some mycelial ascomycetous fungi.

Sentinel Lymph Node Biopsy in Breast Cancer: Guidelines and Pitfalls of Lymphoscintigraphy and Gamma Probe Detection

Abstract: Background: Sentinel node (SN) biopsy appears to offer an alternative to routine axillary lymph node dissection (ALND) for staging patients with breast cancer Various techniques have been studied for identifying the SN, using vital blue dye or radioactive colloid, and initial reports are promising The inherent limitations and pitfalls must be clearly understood before SN biopsy can be implemented in clinical practice Study Design: In a prospective trial, the feasibility of using lymphoscintigraphy and gamma probe detection for performing SN biopsy was studied In 130 consecutive patients with T1–T2, N0 breast cancer, preoperative lymphoscintigraphy was performed with technetium 99m-colloidal albumin During ALND, the radioactive axillary SNs were localized by the gamma probe Histopathologic examination of the harvested SNs was compared with the status of the axillary lymph nodes Results: Axillary focal accumulations were clearly identified on lymphoscintigraphy in 116 patients (89%) The failure rate was significantly higher in patients who had a previous excision biopsy (36%) than in those with a palpable tumor in situ (4%) Using the gamma probe, radiolabeled axillary SNs were successfully biopsied in 122 patients (94%) Because 18 of these patients did not undergo formal lymphadenectomy, the predictive accuracy of SN biopsy was analyzed in 104 patients Radioactive nodes revealed metastases in 44 of 104 patients (42%); in 26 of them (59%), these were the only involved axillary nodes The SN was negative in 60 patients (58%); in one patient the ALND was found to contain metastatic disease (17% false negatives) Biopsy of the SN was 98% accurate in predicting the absence of nodal metastases Conclusions: There are certain guidelines for performing SN biopsy by lymphoscintigraphy and gamma probe detection Success depends primarily on an adequate functional capacity of the SN, necessary for sufficient nodal uptake to ensure accurate identification Lymphoscintigraphy defines the pattern of lymph flow and may prevent failure or false-negative biopsies Biopsy of the SN is a highly accurate, minimally invasive method of staging patients with breast cancer and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary ALND in the majority of patients

Kernel Codebooks for Scene Categorization

Abstract: This paper introduces a method for scene categorization by modeling ambiguity in the popular codebook approach. The codebook approach describes an image as a bag of discrete visual codewords, where the frequency distributions of these words are used for image categorization. There are two drawbacks to the traditional codebook model: codeword uncertainty and codeword plausibility. Both of these drawbacks stem from the hard assignment of visual features to a single codeword. We show that allowing a degree of ambiguity in assigning codewords improves categorization performance for three state-of-the-art datasets.