Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field.

We present the design and operation of a fiber-based cryogenic confocal microscope. It is designed as a compact cold-finger that fits inside the bore of a superconducting magnet, and which is a modular unit that can be easily swapped between use in a dilution refrigerator and other cryostats. We aimed at application in quantum optical experiments with electron spins in semiconductors and the design has been optimized for driving with and detection of optical fields with well-defined polarizations. This was implemented with optical access via a polarization maintaining fiber together with Voigt geometry at the cold finger, which circumvents Faraday rotations in the optical components in high magnetic fields. Our unit is versatile for use in experiments that measure photoluminescence, reflection, or transmission, as we demonstrate with a quantum optical experiment with an ensemble of donor-bound electrons in a thin GaAs film.

QTL mapping of 1000-kernel weight, kernel length, and kernel width in bread wheat (Triticum aestivum L.).

Kernel size and morphology influence the market value and milling yield of bread wheat (Triticum aestivum L.). The objective of this study was to identify quantitative trait loci (QTLs) controlling kernel traits in hexaploid wheat. We recorded 1000-kernel weight, kernel length, and kernel width for 185 recombinant inbred lines from the cross Rye Selection 111 × Chinese Spring grown in 2 agro-climatic regions in India for many years. Composite interval mapping (CIM) was employed for QTL detection using a linkage map with 169 simple sequence repeat (SSR) markers. For 1000-kernel weight, 10 QTLs were identified on wheat chromosomes 1A, 1D, 2B, 2D, 4B, 5B, and 6B, whereas 6 QTLs for kernel length were detected on 1A, 2B, 2D, 5A, 5B and 5D. Chromosomes 1D, 2B, 2D, 4B, 5B and 5D had 9 QTLs for kernel width. Chromosomal regions with QTLs detected consistently for multiple year-location combinations were identified for each trait. Pleiotropic QTLs were found on chromosomes 2B, 2D, 4B, and 5B. The identified genomic regions controlling wheat kernel size and shape can be targeted during further studies for their genetic dissection.

Cellular fixation. A study of CytoRich Red and Cytospin Collection Fluid.

OBJECTIVE: To test a new fixative system (Roche Image Analysis System, Inc. [RIAS]) that may create a background free of blood and blood products, and to determine if the CytoRich Red system has a potential for automation of nongynecologic cytology. We compared the amount of red blood cells, background material and diagnostic ability in 40 bloody specimens prepared using the CytoRich Red system and our routine fixative, Cytospin Collection Fluid (Shandon, Inc.). STUDY DESIGN: Thirty bloody, nongynecologic specimens and 10 fresh FNA surgical specimens were prepared by adding specimen to equal volumes (10 mL) of CytoRich Red Fixative and Cytospin Collection Fluid. After initial centrifugation, the specimens were resuspended and cytocentrifuged using the Cytospin III (Shandon, Inc.) and the Hettich Universal cytocentrifuge. To test system dependency, specimens from each fixative were prepared using the alternate method of cytocentrifugation. Slides from both fixatives were stained, coverslipped and reviewed for the presence of red blood cells, background and diagnostic ability. RESULTS: Of the 40 CytoRich Red specimens, 92.5% (37) had little or no red blood cells as compared to 22.5% (9) of the 40 Cytospin Collection Fluid specimens. Seventy five percent (30) of the 40 CytoRich Red specimens showed reduction of background material in contrast to 15% (6) of the 40 Cytospin Collection Fluid specimens. Diagnostic ability using CytoRich Red was enhanced by the reduction of red blood cells and background material. CytoRich Red performed equally as well with each cytocentrifugation device. CONCLUSION: CytoRich Red reduces red blood cells and background. Nuclear and cytoplasmic stain appear improved. This allows better evaluation of the cytologic features and interpretation of bloody specimens. It is non-system dependent and can be used with any method of preparation. Also, the reduction of background and blood lends itself to adaptation in the automation of nongynecologic cytology.

CD34 immunoreactivity in nervous system tumors.

CD34 is a sialylated transmembrane glycoprotein of unknown function that is present in myeloid progenitor cells, endothelial cells, and some fibroblast-related mesenchymal cells. However, its tissue distribution is still incompletely characterized. In this study we evaluated the distribution of CD34 antigen in tumors of the central and peripheral nervous system. For comparison the tumors were also stained for CD31, also known as platelet-endothelium cell adhesion molecule (PECAM-1), a transmembrane glycoprotein so far considered to be endothelium specific beyond its reactivity with certain hematopoietic cells. Neurofibromas showed consistently high numbers of CD34-positive spindle cells, whereas peripheral and acoustic schwannomas were negative. A subset of meningiomas (15%) showed CD34-positive tumor cells, and some were also weakly positive for CD31. Gliomas were negative. Meningeal hemangiopericytomas were consistently CD34 positive, but CD31 negative. These results indicate a moderately widespread distribution of the CD34 antigen in nervous system tumors, and necessitate caution in making conclusions regarding endothelial cell differentiation of nervous system tumors on the basis of CD34 immunoreactivity.

Endothelial cell markers CD31, CD34, and BNH9 antibody to H- and Y-antigens--evaluation of their specificity and sensitivity in the diagnosis of vascular tumors and comparison with von Willebrand factor.

Sixty vascular tumors including 23 angiosarcomas, 300 nonvascular tumors, and selected normal tissues were immunohistochemically evaluated with antibodies to CD31, CD34, and von Willebrand factor (vWF), and monoclonal antibody BNH9, to test the sensitivity and specificity of these markers in the identification of endothelial cells and vascular tumors. Formaldehyde-fixed paraffin-embedded tissues and avidin biotin complex immunostaining were used. All markers labeled normal vascular and lymphatic endothelial cells approximately equally with the exception of CD34 which showed inconsistent expression within the lymphatics. In addition, antibody to CD31 reacted with platelets and megakaryocytes, CD34 with fibroblasts and aortic smooth muscle cells, and BNH9 with many epithelial cells including squamous and gastrointestinal epithelia. Antibody to vWF often showed significant stromal background staining which made the staining occasionally uninterpretable. Benign vascular tumors showed rather uniform staining with all antibodies. However, angiosarcomas were heterogeneous; CD31 was positive in 21/27, CD34 in 25/27 cases, BNH9 in 22/25, and vWF in 18/27 cases. Epithelioid hemangioendotheliomas showed consistent labeling for vWF, but were inconsistently labeled with antibodies to the other markers. Kaposi's sarcoma was positive for both CD31 and CD34. In addition, antibody to CD34 labeled the tumor cells in hemangiopericytoma, cerebellar hemangioblastoma, meningioma, most epithelioid sarcomas, dermatofibrosarcomas, and in a few other sarcomas. CD31, in turn, was not found in sarcomas other than angiosarcomas, but labeled weakly occasional carcinomas and mesotheliomas. Many adenocarcinomas and the glandular component of synovial sarcoma were BNH9 positive.(ABSTRACT TRUNCATED AT 250 WORDS)