Jitakshi De

In Saccharomyces cerevisiae chromosomal DNA replication initiates at intervals of approximately 40 kb and depends upon the activity of autonomously replicating sequence (ARS) elements. The identification of ARS elements and analysis of their function as chromosomal replication origins requires the use of functional assays because they are not sufficiently similar to identify by DNA sequence analysis. To complete the systematic identification of ARS elements on S. cerevisiae chromosome III, overlapping clones covering 140 kb of the right arm were tested for their ability to promote extrachromosomal maintenance of plasmids. Examination of chromosomal replication intermediates of each of the seven ARS elements identified revealed that their efficiencies of use as chromosomal replication origins varied widely, with four ARS elements active in < or = 10% of cells in the population and two ARS elements active in > or = 90% of the population. Together with our previous analysis of a 200-kb region of chromosome III, these data provide the first complete analysis of ARS elements and DNA replication origins on an entire eukaryotic chromosome.

Flow cytometry and other technologies of cell-based fluorescence assays are as a matter of good laboratory practice required to validate all assays, which when in clinical practice may pass through regulatory review processes using criteria often defined with a soluble analyte in plasma or serum samples in mind. Recently the U.S. Food and Drug Administration (FDA) has entered into a public dialogue in the U.S. regarding their regulatory interest in laboratory developed tests (LDTs) or so-called home brew assays performed in clinical laboratories. The absence of well-defined guidelines for validation of cell-based assays using fluorescence detection has thus become a subject of concern for the International Council for Standardization of Haematology (ICSH) and International Clinical Cytometry Society (ICCS). Accordingly, a group of over 40 international experts in the areas of test development, test validation, and clinical practice of a variety of assay types using flow cytometry and/or morphologic image analysis were invited to develop a set of practical guidelines useful to in vitro diagnostic (IVD) innovators, clinical laboratories, regulatory scientists, and laboratory inspectors. The focus of the group was restricted to fluorescence reporter reagents, although some common principles are shared by immunohistochemistry or immunocytochemistry techniques and noted where appropriate. The work product of this two year effort is the content of this special issue of this journal, which is published as 5 separate articles, this being Validation of Cell-based Fluorescence Assays: Practice Guidelines from the ICSH and ICCS - Part IV - Postanalytic considerations.

Unilateral Agenesis of Internal Carotid Artery with Ophthalmic Artery Arising from Posterior Communicating ArteryRamin M. Naeini1, Jitakshi De2, Tetsu Satow1 and Goetz Benndorf1Audio Available | Share

Anaplastic large cell lymphoma (ALCL) is a distinct type of T/null-cell non-Hodgkin lymphoma that commonly involves nodal and extranodal sites. The World Health Organization of lymphoid neoplasms recognizes two types: anaplastic lymphoma kinase (ALK) positive or ALK negative, the former as a result of abnormalities involving the ALK gene at chromosome 2p23. Patients with ALCL rarely develop a leukemic phase of disease, either at the time of initial presentation or during the clinical course. Described herein is a patient with ALK+ ALCL, small cell variant, associated with the t(2;5)(p23;q35), who initially presented with leukemic involvement and an extraordinarily high leukocyte count of 529 x 10(9)/L, which subsequently peaked at 587 x 10(9)/L. Despite chemotherapy the patient died 2(1/2) months after diagnosis. In the literature review 20 well-documented cases are identified of ALCL in leukemic phase reported previously, with a WBC ranging from 15 to 151 x 10(9)/L. Leukemic phase of ALCL occurs almost exclusively in patients with ALK+ ALCL, most often associated with the small cell variant and the t(2;5)(p23;q35), similar to the present case. Patients with leukemic phase ALK+ ALCL appear to have a poorer prognosis than most patients with ALK+ ALCL.