Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Microtomy”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1979

Microphotometric determination of enzyme activities in cryostat sections by the gel film technique.

Use of the gel film technique in microphotometric determinations of enzyme activity is described. The microscope photometer is computer-controlled. It is programmed to deal with repetitive measurements at up to 12 selected positions within a tissue section and to evaluate recorded reaction rates statistically. Films of polyacrylamide gel with entrapped glucose-6-phosphate dehydrogenase are used as a model to demonstrate the correlation between local enzyme activity and the microphotometrically determined reaction rate. Enzyme activities at different positions in the same tissue section are determined and compared. Activity profiles of five enzymes (glutamate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, NAD-dependent tetrazolium reductase) in the liver are presented and show non-uniform intra-acinar distribution patterns. These results are interpreted in the light of the metabolic zonation of the hepatic acinus. Further applications of the method are discussed.

Animals↗
PubMed1979

Three-dimensional architecture of the golgi apparatus in Sertoli cells of the rat.

Glutaraldehyde-fixed testes were stained "en bloc" with the Ur-Pb-Cu technique of Thiéry and Rambourg ('76) or post-fixed and stained with the osmium tetroxide-potassium ferrocyanide method of Karnovsky ('71). Thin or thick (up to 3 micron) sections were examined with the Philips (301 or 400) EM or the high voltage EM. Stereopairs were prepared with photographs of tilted specimens (+/- 7 degrees). At low magnification, in thick sections (0.5-3 micron) stained with Ur-Pb-Cu, the whole Golgi apparatus formed a single network of interconnected wavy ribbon or platelike structures extending from the juxtanuclear region toward the apex of the cell. At higher magnifications, with the two staining techniques, this Golgi network showed two distinct types of regions: the "saccular region" corresponding to the conventional stack of saccules and the "intersaccular connecting region" made up of anastomotic tubules which bridge adjacent stacks. In the saccurlar regions, there was, on the cis-face of the stack, a tight polygonal meshwork of anastomotic tubules (osmiophilic element). Underlying it there were three to seven closely apposed saccules perforated with pores of various diameters, and finally, on the trans-face, a network of tubules was usually connected to the last saccule of the stack, which seemed to peel off" from the pile. The intersaccular connecting regions showed proximal and distal zones with regard to the associated stacks. The proximal zone was made up of superimposed and parallel polygonal networks of membranous tubules which were continuous with corresponding saccules of the stack. In the distal zone they interdigitated, intertwined, anastomosed and bridged adjacent saccular regions; others turned at right angles and established connections with tubular extensions arising at various levels of the same stack. While cisternae of endoplasmic reticulum were contiguous with tubules or saccules located on the transface of the Golgi apparatus, a close association between the ER cisternae and the cis-face of the stacks was not usually observed.

Animals↗
PubMed1979

Morphogenesis of the truncus arteriosus of the chick embryo heart: the formation and migration of mesenchymal tissue.

The appearance and migration of mesenchymal cushion tissue within the truncus arteriosus of the normal 2.5 to 6-day chick embryo heart was surveyed systemically with the light microscope. Series of cross-sections taken from replicate hearts at successive developmental stages allowed comparison of the following qualitative and quantitative aspects of early truncal morphogenesis. Mesenchyme within the truncus was derived from two distinct sources. The first mesenchyme appeared to migrate caudally into the cardiac jelly of the distal truncus from the nearby aortic arch region, coincident with slowing of the anterior elongation of the heart tube (Hamburger-Hamilton Stage 17-18). A second, separate mesenchymal population, derived from endocardium, began to fill the conus and proximal truncus in a radial direction, coicident with expansion of the bulbs cordis (Stage 12-19). The measured kinetics of relative cell numbers, distributions, and mitotic indices suggest substantial contributions from both sources. By Stage 26, the conotruncal region was filled with mesenchyme, which then condensed to form the anlagen of three future structures: the semilunar valves, the aorticopulmonary septum, and the tunica media of the great arteries.

Animals↗
PubMed1989

Postnatal growth of pulmonary acini and alveoli in normal and oxygen-exposed rats studied by serial section reconstructions.

Three-dimensional reconstructions from serial sections were used to examine postnatal lung development of rats reared in air (control) or oxygen. From birth to age 21 days, control lung volume increased ninefold, and the average volume of each ventilatory unit (all airspaces distal to a single respiratory bronchiole) increased seven times. There were approximately 5,000 ventilatory units at birth and on day 21, indicating that the lung grew by enlargement and subdivision of ventilatory units and not by their multiplication. Growth in hyperoxia (greater than 97%) for 7 days had no effect on the number of ventilatory units but, compared to controls, total lung volume and ventilatory unit volume were reduced 32% and 16%, respectively. At birth there were 0.6 x 10(6) alveoli, and at age 7 days in controls alveolar number increased 16-fold while the average volume of a single alveolus fell to one-sixth that at birth. Exposure to hyperoxia for 7 days stopped alveolarization; the surface area to volume ratio (Sa/V) of the ventilatory unit was lower, alveolar number was the same as at birth, and the alveoli present were large. At age 21 days, after 14 days of recovery in air, lung volume and ventilatory unit volume were greater than in controls but the Sa/V of the ventilatory unit was still depressed 20%. Alveoli from oxygen-exposed lungs were larger than in controls, and a greater size distribution coefficient showed them to be more variable. A shape coefficient for alveoli did not change as a function of the animal's age or oxygen treatment; it demonstrated proportional growth of alveolar height and diameter.

Animals↗
PubMed1986

The distribution of lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin in normal hematopoietic cells and in myeloid leukemias: an immunoperoxidase study on cytocentrifuge preparations, smears, and paraffin sections.

Blood and bone marrow samples from 20 individuals with reactive conditions and 26 cases of acute and chronic myeloid leukemias were tested for the presence of lysozyme, alpha-1-antitrypsin (alpha-1-AT), and alpha-1-antichymotrypsin (alpha-1-ACT). We compared the reactivity of samples in smears, cytocentrifuge preparations, and paraffin sections. Lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin were found only in polymorphonuclear leukocytes and monocytes and their precursors. Lymphocytes, E-rosetting cells, Con A-activated lymphocytes, natural killer (NK) cells, red blood cells, erythroblasts, and megakaryocytes were consistently negative. Leukemic myeloblasts showed definite reactivity for both alpha-1-antitrypsin and alpha-1-ACT, but not for lysozyme. By contrast, lysozyme was present in poorly differentiated leukemic monoblasts, while alpha-1-antitrypsin and alpha-1-antichymotrypsin showed only weak reactivity. More mature myeloid and moncytic cells showed positive staining for all three antigens tested with differences in staining distribution and intensity. In four cases of chronic myeloid leukemia (CML), circulating mature polymorphonuclear leukocytes were deficient in both lysozymne and alpha-1-antitrypsin. The use of lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin identifies normal and leukemic cells of the myeloid-monocytic series at all stages of maturation and is applicable to a variety of sample preparations.

Bone Marrow↗
PubMed1992

Application of immunocryoultramicrotomy to free cells: ultrastructural localization of myeloperoxidase in neutrophils of human peripheral blood.

Immunocryoultramicrotomy is generally considered the most suitable method for observing the immunostainings by monoclonal antibodies to intracellular antigens by electron microscopy. However, this procedure with the free cells such as peripheral blood cells or cultured cells is not widely used because of the difficulty in preparing ultrathin frozen sections. We report here a new technique for making ultrathin frozen sections of peripheral blood cells by positioning the cell in a semigelatinized medium for ultrasectioning. Monoclonal antibody against myeloperoxidase (MPO) was reacted with the ultrathin sections made with this new technique to observe the ultrastructural localization of intracellular MPO. MPO was observed in the primary granules of the neutrophils.

Antibodies, Monoclonal↗
PubMed2002

Methodologies in cancer cytogenetics and molecular cytogenetics.

Various types of cytogenetic and molecular cytogenetic approaches, including conventional banding, fluorescence in situ hybridization (FISH), fiber-FISH, comparative genomic hybridization (CGH), matrix array CGH, chromosome microdissection, and microcell-mediated chromosome transfer are summarized. The rationale, advantage, and limitations of each approach are discussed with respect to research and clinical applications in human neoplasia.

Chromosome Banding↗
PubMed1980

Immunocytochemical method to identify myelin basic protein in oligodendroglia and myelin sheaths of the human nervous system.

To study the distribution of basic protein (BP) and other myelin constituents immunocytochemically in human nervous tissue, we modified the unlabeled antibody enzyme (peroxidase-antiperoxidase) method. The technique is described here. Because the availability of unfixed tissue from human central nervous system is limited, we tested the method on blocks that had been fixed in formalin and embedded in paraffin, fixed and stored in 4% formalin, or frozen at autopsy and stored. We obtained the best results with paraffin blocks. BP antiserum stained oligodendroglia and myelin sheaths in the developing human nervous system. In the adult, myelin sheaths were well stained. Also, abnormalities associated with myelin breakdown could be identified in multiple sclerosis lesions. The results suggest that this method will be useful in studying the cellular distribution of myelin components in human demyelinating diseases.

Adolescent↗
PubMed2001

Effects of brefeldin-A: potent inhibitor of intracellular protein transport on ultrastructure and resorptive function of cultured osteoclasts.

Brefeldin-A (BFA) is a specific and potent inhibitor of the intracellular transport of clathlin-uncoated transitional vesicles from the cisterns of rough-surfaced endoplasmic reticulum (RER) to the Golgi lamellae. This study was designed to clarify the effects of BFA on ultrastructure, subcellular localization of vacuolar-type H+-ATPase and a lysosomal cysteine proteinase, cathepsin K, in cultured osteoclasts and their resorptive function. H+-ATPase and cathepsin K are the most important enzymes for decalcification of apatite crystals and degradation of type-I collagen, respectively. In control cultures without BFA, osteoclasts were structurally characterized by the development of broad ruffled borders and clear zones, and formed many resorption lacunae in cocultured dentine slices. In BFA-treated cultures, osteoclasts lacked ruffled borders, and the cytoplasm was filled with regular-size and extremely large pale vacuoles over 2 microm in diameter, which were produced by fusion of adjacent vacuoles. BFA did not, however, inhibit clear zone formation and adhesion of osteoclasts to dentine slices. Resorption lacuna formation was markedly diminished by BFA treatment. Although H+-ATPase and cathepsin K were strongly expressed in osteoclast ruffled borders in control cultures, BFA treatment altered the subcellular localization and decreased the expression of these molecules. In BFA-treated cultures, H+-ATPase immunoreaction in osteoclasts was observed along the limiting membranes of some, but not all, regular-size pale vacuoles, but neither in extremely large vacuoles nor along the smooth plasma membranes facing the dentine slices. Similarly, cathepsin K was localized within lysosomes and some regular-size pale vacuoles, but its secretion toward the dentine slices through the ruffled borders was strongly inhibited by BFA treatment. These results suggest that 1.) formation of the osteoclast ruffled borders and their resorptive function are closely associated with the intracellular transport of these molecules from the RER cisterns and the Golgi lamellae to the ruffled borders, and 2.) both H+-ATPase and cathepsin K are selectively transported to the ruffled border membranes by pale vacuoles.

Animals↗