How cells (might) sense microgravity. (1/414)

This article is a summary of a lecture presented at an ESA/NASA Workshop on Cell and Molecular Biology Research in Space that convened in Leuven, Belgium, in June 1998. Recent studies are reviewed which suggest that cells may sense mechanical stresses, including those due to gravity, through changes in the balance of forces that are transmitted across transmembrane adhesion receptors that link the cytoskeleton to the extracellular matrix and to other cells (e.g., integrins, cadherins, selectins). The mechanism by which these mechanical signals are transduced and converted into a biochemical response appears to be based, in part, on the finding that living cells use a tension-dependent form of architecture, known as tensegrity, to organize and stabilize their cytoskeleton. Because of tensegrity, the cellular response to stress differs depending on the level of pre-stress (pre-existing tension) in the cytoskeleton and it involves all three cytoskeletal filament systems as well as nuclear scaffolds. Recent studies confirm that alterations in the cellular force balance can influence intracellular biochemistry within focal adhesion complexes that form at the site of integrin binding as well as gene expression in the nucleus. These results suggest that gravity sensation may not result from direct activation of any single gravioreceptor molecule. Instead, gravitational forces may be experienced by individual cells in the living organism as a result of stress-dependent changes in cell, tissue, or organ structure that, in turn, alter extracellular matrix mechanics, cell shape, cytoskeletal organization, or internal pre-stress in the cell-tissue matrix.--Ingber, D. How cells (might) sense microgravity.  (+info)

Mapping the literature of cytotechnology. (2/414)

The major purpose of this study was to identify and assess indexing coverage of core journals in cytotechnology. It was part of a larger project sponsored by the Nursing and Allied Health Resources Section of the Medical Library Association to map the literature of allied health. Three representative journals in cytotechnology were selected and subjected to citation analysis to determine what journals, other publication types, and years were cited and how often. Bradford's Law of Scattering was applied to the resulting list of cited journals to identify core titles in the discipline, and five indexes were searched to assess coverage of these core titles. Results indicated that the cytotechnology journal literature had a small core but wide dispersion: one third of the 21,021 journal citations appeared in only 3 titles; another third appeared in an additional 26 titles; the remaining third were scattered in 1,069 different titles. Science Citation Index Expanded rated highest in indexing coverage of the core titles, followed by MEDLINE, EMBASE/Excerpta Medica, HealthSTAR, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). The study's results also showed that journals were the predominantly cited format and that citing authors relied strongly on more recent literature.  (+info)

Antibodies and sperm survival in the female tract of the mouse and rabbit. (3/414)

Rabbit and mouse spermatozoa from male and female tracts have been examined for their species-antigenic surface character, and for adherent antibodies, by double immunofluorescence techniques. Mouse spermatozoa from the ductus deferens showed an area over the acrosome which was positive to anti-mouse serum that had been absorbed with some male mouse somatic tissues including blood, but those from the uterus and oviduct were not stained. Spermatozoa from the uterus were shown to have an antibody coat on the acrosome, with anti-mouse IgG, but those from the ductus deferens and oviduct did not. Rabbit spermatozoa were more variable but their activity was similar: ejaculated spermatozoa sometimes already had antibody of male origin; the majority of the spermatozoa arriving early in the uterus were coated, but in general those that attained the oviducts were not coated. The results are interpreted as evidence for selection by the female tract of a small antigenically different population; the majority of spermatozoa are rejected and/or destroyed.  (+info)

A new miniature hydrostatic pressure chamber for microscopy. Strain-free optical glass windows facilitate phase-contrast and polarized-light microscopy of living cells. Optional fixture permits simultaneous control of pressure and temperature. (4/414)

This paper describes the development of a miniature, temperature-controlled, stainless steel pressure chamber which uses strain-free optical glass for windows. It is directly adaptable to standard phase-contrast and polarized-light microscopes and requires a minimum amount of equipment to generate and measure pressure. Birefringence retardation (BR) og 0.1 nm up to 3,000 psi, 0.4 nm up to 5,000 psi and 1.0 nm up to 10,000 psi can be detected over a 0.75-mm central field with two strain-free Leitz 20 times UM objectives, one used as a condenser. In phase-contrast studies a Nikon DML 40 times phase objective and Zeiss model IS long working-distance phase condenser were used, with little deterioration of image quality or contrast at pressures as high as 12,000 psi. The actual design process required a synthesis of various criteria which may be categorized under four main areas of consideration: (a) specimen physiology; (b) constraints imposed by available optical equipment and standard microscope systems; (c) mechanical strength and methods for generating pressure; and (d) optical requirements of the chamber windows. Procedures for using the chambers, as well as methods for shifting and controlling the temperature within the chamber, are included.  (+info)

Prototype Web-based continuing medical education using FlashPix images. (5/414)

Continuing Medical Education (CME) is a requirement among practicing physicians to promote continuous enhancement of clinical knowledge to reflect new developments in medical care. Previous research has harnessed the Web to disseminate complete pathology CME case studies including history, images, diagnoses, and discussions to the medical community. Users submit real-time diagnoses and receive instantaneous feedback, eliminating the need for hard copies of case material and case evaluation forms. This project extends the Web-based CME paradigm with the incorporation of multi-resolution FlashPix images and an intuitive, interactive user interface. The FlashPix file format combines a high-resolution version of an image with a hierarchy of several lower resolution copies, providing real-time magnification via a single image file. The Web interface was designed specifically to simulate microscopic analysis, using the latest Javascript, Java and Common Gateway Interface tools. As the project progresses to the evaluation stage, it is hoped that this active learning format will provide a practical and efficacious environment for continuing medical education with additional application potential in classroom demonstrations, proficiency testing, and telepathology. Using Microsoft Internet Explorer 4.0 and above, the working prototype Web-based CME environment is accessible at http://telepathology.upmc.edu/WebInterface/NewInterface/welcome.html.  (+info)

A brief history of the Japan Society for Cell Biology. (6/414)

The Japan Society for Cell Biology (JSCB) was first founded in 1950 as the Japan Society for Cellular Chemistry under the vigorous leadership of Seizo Katsunuma, in collaboration with Shigeyasu Amano and Satimaru Seno. The Society was provisionally named as above simply because cell biology had not yet been coined at that time in Japan, although in prospect and reality the Society was in fact for the purpose of pursuing cell biology. Later in 1964, the Society was properly renamed as the Japan Society for Cell Biology. After this renaming, the JSCB made great efforts to adapt itself to the rapid progress being made in cell biology. For this purpose the Society's constitution was created in 1966 and revised in 1969. According to the revised constitution, the President, Executive Committee and Councils were to be determined by ballot vote. The style of the annual meetings was gradually modified to incorporate general oral and poster presentations in addition to Symposia (1969-1974). The publication of annual periodicals in Japanese called Symposia of the Japan Society for Cellular Chemistry (1951-1967) and later Symposia of the Japan Society for Cell Biology (1968-1974) was replaced by a new international journal called Cell Structure and Function initiated in 1975. This reformation made it possible for the Society to participate in the Science Council of Japan in 1975 and finally in 1993 to acquire its own study section of Cell Biology with grants-in-aid from the Ministry of Education and Science, Japan. The JSCB hosted the 3rd International Congress on Cell Biology (ICCB) in 1984 and the 3rd Asian-Pacific Organization for Cell Biology (APOCB) Congress in 1998, thus contributing to the international advancement of cell biology. Now the membership of JSCB stands at approximately 1,800 and the number of presentations per meeting is 300 to 400 annually. Although a good number of interesting and important findings in cell biology have been reported from Japan, the general academic activity of the JSCB is far less than one might expect. This is simply due the fact that academic activity in the field of cell biology in Japan is divided among several other related societies such as the Japan Society for Molecular Biology and the Japan Society for Developmental Biology, among others.  (+info)

Myocardial lysis in acute rheumatic fever followed by regeneration of cardiac muscle and origin of Aschoff bodies. (7/414)

In acute rheumatic heart disease, lysis of cardiac muscle fibres with or without retention of sarcolemma is found to be the most damaging feature in many cases. In deeper myocardium the cellular lysis often forms anastomosing clefts or sinus-like spaces between surviving muscle bundles and in the outer portion of myocardium cellular lysis may leave the sarcolemma more or less intact. From lysing cardiac muscle fibres there arise dedifferentiated cells with remarkable potentiality for regeneration. For the origin of these dedifferentiated cells, which are often indistinguishable from lymphocytes, no mitosis is seen in cardiac muscle cells. The successive stages of development of muscle cell from these dedifferentiated cells within the remaining or newly formed sarcolemma have been observed in this study. This study infers that the increased number of fibrous septa, when seen, denotes the tracks of previous muscle degeneration and subsequent replacement of it with incomplete muscle regeneration and fibrous tissue formation. In an area of muscle lysis the origin of Aschoff bodies from these dedifferentiated cells has been followed. Ashoff bodies arising in this was behave as an abortive and atypical growth of muscle fibres in a nodular fashion specific to rheumatic fever.  (+info)

Papanicolaou tests diagnosed as atypical by a cytotechnologist and downgraded to benign by a pathologist: a measure of laboratory quality. (8/414)

Follow-up of Papanicolaou (Pap) tests diagnosed as atypical squamous cells of undetermined significance (ASCUS) or atypical glandular cells of undetermined significance (AGUS) by a cytotechnologist and downgraded to benign by a pathologist has not been measured. Squamous intraepithelial lesion (SIL) follow-up rates were obtained for Pap tests diagnosed as ASCUS (288) or AGUS (94) and downgraded to benign and for Pap tests diagnosed as repair (231). Statistically significant associations were seen between 7 cytotechnologists and between 7 pathologists and ASCUS, AGUS, downgraded ASCUS, and downgraded AGUS rates. The percentage of downgraded ASCUS cases compared with all ASCUS cases per pathologist ranged from 4.8% to 43.7%. Statistically significant associations between pathologists and SIL follow-up rates for downgraded ASCUS diagnoses were seen. The SIL follow-up rate for repair (7.9%) was similar to that for a downgraded ASCUS (11.0%) or AGUS (7.3%). The parameters of downgraded ASCU and AGUS Pap test interpretations are good quality indicators of individual performance and overall laboratory quality.  (+info)