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Molecular Examination (molecular + examination)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Diffuse large B-cell lymphoma arising independently to lymphoplasmacytic lymphoma: a case of two lymphomas

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 3 2007
Tetsuaki Sekikawa
Abstract Richter's syndrome occurs in 5,10% of patients with chronic lymphocytic leukemia, either by transformation of the primary neoplastic lymphocyte, or as a distinct B-cell neoplasm. We report a Japanese patient with lymphoplasmacytic lymphoma in whom a diffuse large B-cell lymphoma developed after treatment with rituximab. Molecular examination on immunoglobulin VH genes revealed that the lymphomas had arisen in two separate clones. We reviewed clinical case reports in literature, and found 30,40% of cases with Richter's syndrome and composite lymphoma had a second B-cell lymphoma of a different origin. [source]

Monochorionic-diamniotic twins discordant in gender from a naturally conceived pregnancy through postzygotic sex chromosome loss in a 47,XXY zygote

PRENATAL DIAGNOSIS, Issue 8 2008
Nicolas H. Zech
Abstract Objective It is generally believed that monochorionic-diamniotic twin pregnancies result from one fertilized oocyte with both siblings having the same genotype and phenotype. In rare instances, due to somatic mutations or chromosome aberrations, the karyotypes and phenotypes of the two twins can differ. Method We report cytogenetic, molecular genetic and clinical examinations in monochorionic-diamniotic twins discordant in gender. Results The monochorionic-diamniotic status of the twins was diagnosed by ultrasound and histologic examination of the placenta. Prenatal chromosome examination performed on amniocytes revealed a normal female karyotype in one and a 46,XX(26)/46,XY(3) karyotype in the other twin. Molecular examinations confirmed monozygosity despite discordant sex. Based on the cytogenetic and molecular results of lymphocytes and placental cells, the only explanation for gender discordance was that the conceptus originally had a 47,XXY chromosome complement. Conclusion A 47,XXY zygote appears to have undergone a twinning process. A postzygotic loss of the X chromosome in some cells and the Y chromosome in other cells, either before or after twinning, resulted in 46,XX/46,XY mosaicism in both monozygotic (MZ) twins. The sex discordance of the MZ twins can be explained by different proportions of the 46,XX and 46,XY cell lines in the gonads and other tissues. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Morphological and molecular examination of relationships and epitype establishment of Phacus pleuronectes, Phacus orbicularis, and Phacus hamelii,

JOURNAL OF PHYCOLOGY, Issue 5 2007
Sylwia Kosmala
Verification of morphological diagnostic features and the establishment of three epitypes for three species of Phacus Dujardin,Phacus pleuronectes (O. F. Müll.) Dujardin, Phacus orbicularis Hübner, and Phacus hamelii Allorge et Lefèvre,was performed based on literature studies and analysis of morphological (cell shape, cell size, and periplast ornamentation) as well as molecular (18S rDNA) characters. Periplast ornamentation was recognized as a main diagnostic character, distinguishing P. orbicularis from P. pleuronectes and P. hamelii. Phacus orbicularis has struts running perpendicular to the longitudinal axis of the strips, while P. pleuronectes and P. hamelii do not. On the SSU rDNA tree, obtained by the Bayesian method, P. orbicularis, P. pleuronectes, and P. hamelii belong to three distinct clades. Some of the phylogenetic relationships are not resolved, but there are at least three Phacus species (P. hamatus, P. platyaulax, P. longicauda; for taxonomic authors, see Introduction) that are more closely related to P. orbicularis than is P. pleuronectes. Phacus hamelii is more closely related to P. ranula and the assemblage of several species of Phacus, which have small cells, than to P. orbicularis or P. pleuronectes. [source]

Expression of Angiogenic Growth Factors in Paragangliomas,

THE LARYNGOSCOPE, Issue 1 2000
Robert W. Jyung MD
Abstract Objective/Hypothesis: To determine if angiogenic growth factors including vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF) are expressed in human paragangliomas. Study Design: A histopathologic and molecular examination of paraganglioma specimens obtained from surgical cases or retrieved from the Pathology Department of the Massachusetts Eye and Ear Infirmary. Methods: Fresh tumor or archival, paraffin-embedded paraganglioma specimens were analyzed by immunohistochemistry, Western blotting, and ELISA. Results: Positive immunohistochemical staining for VEGF was observed in five of nine surgical specimens and in six of eight archival specimens (11/17, or 65%). PD-ECGF immunoreactivity was detected in four of five surgical specimens and six of eight archival specimens (10/13, or 77%). The presence of PD-ECGF was confirmed by Western blot assay and ELISA confirmed the presence of VEGF in tumor extract. Conclusions: Both VEGF and PD-ECGF are expressed in paragangliomas and may contribute to the extreme vascularity of these tumors. [source]