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At least 721 records · Page 40Linked to original sources
PubMed1990

In situ hybridization of semithin Epon sections with BrdU labelled oligonucleotide probes.

We recently described a nonradioactive method for in situ hybridization with 5-bromo-2-deoxyuridine (BrdU) labelled oligonucleotide probes. An antibody to BrdU and immunocytochemistry were used in order to detect the hybridization signal. We have now applied this method to semithin Epon sections, in order to hybridize consecutive sections through single cells with different probes and to stain them with antibodies to neuropeptides. It could be shown that Epon embedding reserves mRNA well. In the present study we used a BrdU labelled synthetic oligonucleotide probe complementary to a fragment of the vasopressin precursor and an antibody to Arg-vasopressin. Vasopressin mRNA was demonstrable in a fraction of the vasopressin immunoreactive neurons in the magnocellular nuclei. In addition some of the magnocellular neurons showed either hybridization or vasopressin immunostaining only, perhaps indicating different stages of synthetic and secretory activity. The method described seems to be a valuable tool for studying synthetic activity in peptidergic neurons on a single cell level. The method might also have potential for in situ hybridization on the electron-microscopical level.

Animals↗
PubMed1997

Expression and distribution of voltage-sensitive sodium channels in pyrethroid-susceptible and pyrethroid-resistant Musca domestica.

Knockdown resistance (kdr) to pyrethroid insecticides has been found in numerous insect species. kdr causes nerve insensitivity by altering the primary target of these insecticides, the voltage-sensitive sodium channel. In Musca domestica, cloning and sequencing of susceptible, kdr, and super-kdr alleles of the sodium channel gene (Msc) homologous to the Drosophila melanogaster para channel gene has revealed point mutations. The conservation of the nature and of the position of these mutations strongly suggests a role in the kdr mechanism. To determine if these mutations are associated with modifications of channel expression in adult flies, we investigated the localization of the Msc transcripts, and the size and the tissue distribution of the channel protein in pyrethroid-susceptible and super-kdr strains. Msc channels were mainly found in the cortical regions of the central nervous system with additional labeling in some neuronal processes and in the eyes. No qualitative or quantitative difference was observed between the strains. In immunoblotting experiments, anti-Msc antibodies bound to only one polypeptide of 260 kDa in adult brain. No differences were found in antibody staining between susceptible and pyrethroid-resistant strains. These results were correlated with those on Drosophila melanogaster, for which two sodium channel genes have been identified.

Age Factors↗
PubMed1996

Two- and three-dimensional demonstrations of morphological alterations of early anagen hair follicle with special reference to the bulge area.

During late telogen to early anagen secondary hair germ is newly formed by the downgrowth of a clubbed column which is indistinguishable from the bulge. Serial vertical sections demonstrated that the early anagen terminal hair follicle formed the new secondary hair germ associated with a lateral protuberance of basaloid cells which could be considered as the bulge of the new hair follicle. Interestingly, the arrector pili muscle bundle was divided into two branches, one inserted into the original clubbed end and the other into this protuberance of the secondary hair germ. CAM5.2-reactive Merkel cells were present not only in the clubbed ends of the old follicle but also in the protuberance of the new hair germ. The formation of the lateral protuberance of the new hair germ preceded the appearance of CAM5.2-reactive Merkel cells in this location. Ks19.1 immunoreactivity was observed from the clubbed end to the upper half of the new hair germ. These phenomena occurred in early anagen before the club hairs were shed. It is postulated that the early anagen hair follicle formed the area within the new hair germ equivalent to the bulge and Merkel cells either moved from the bulge of the old hair follicle or differentiated de novo from immature epithelial cells. Merkel cells or their products in the bulge may serve as attractants for the readjusting arrector pili muscle to anchor to the bulge of the new hair follicle.

Edetic Acid↗
PubMed1998

Imaging and modelling from serial microscopic sections for the study of anatomy.

A system is considered for segmenting noisy intensity images and consequent three-dimensional object reconstruction from a set of planar contours. A new semi-automatic method for the extraction of contours from a sequence of cross-sectional images based on an active contour model (ACM) is proposed. The dynamic ACM proceeds along the sequence of cross-sections following a non-rigid motion, in accordance with the organ boundary. Image texture information is also employed in the model. Problems associated with topological reconstruction from planar contours are addressed, and several criteria promoting semi-automatic topological reconstruction are introduced. The proposed system is successfully applied to the processing of real data related to animal embryonic organs, proving that the system allows detailed modelling of irregular objects. The reconstructed models can be observed in wire-frame, solid, transparent or stereoscopic semi-transparent format. The human-computer interaction implemented in the procedure assists with problems of feature identification and object manipulation about an arbitrary axis.

Anatomy↗
PubMed1975

A precision microdissection procedure for undecalcified bone thin sections.

A procedure is described for removing osteons from undecalcified, thin sections of bone. The method involves the use of a microdrilling machine in combination with a micromanipulator. The procedure allows a substantial reduction in the time required for microdissection over previously described methods while permitting the irregular contours of osteons to be followed with precision.

Bone and Bones↗
PubMed1985

An evaluation of various plastic embedding methods for preparing ground sections from calcified tissue with the Logitech system for light microscopy.

Three plastic processing methods for preparing ground sections from hard tissue applicable to light microscopy are reviewed. The requirement for production of high quality ground sections of tooth and bone for pathological diagnosis is discussed and a new machine system technology, namely the LP 30 Lapping Machine (Logitech Ltd., Dunbartonshire, Scotland) which meets these requirements is described. The new approach is justified by the results, since sections of quality are produced with increased efficiency, while the operator's working conditions are distinctly improved. Ground sections, 10-20 microns, are being produced from glycol methacrylate impregnated specimens with the employment of the Leitz diamond saw and the Logitech section grounding system. Good GMA ground sections form an invaluable aid to microscopic diagnosis of many disorders of enamel as well as metabolic bone diseases.

Acrylates↗
PubMed1989

Histomorphometry of fresh frozen iliac crest bone biopsies.

Although methods are well established for the rapid histological preparation of fresh frozen soft tissues, they remain inadequate for the preservation of hard tissues. A recent technique for sectioning fresh frozen bone, in which sections can be prepared within an hour, has been applied to undecalcified human iliac crest bone biopsies. Quantitative analysis has shown that the static remodeling variables deduced from frozen sections closely resemble those derived from plastic-embedded sections prepared for routine use by established laboratory procedures. It is concluded that the rapid method is reliable for immediate diagnostic and histomorphometric purposes.

Biopsy↗
PubMed1985

A method to prepare bone-implant specimens for laboratory analysis.

A method for the preparation of bone samples containing metallic implants is presented. Technics are detailed for samples to be analyzed by mechanical, microradiographical and microangiographical means, and by tetracycline labeled fluorescent and polarized light microscopy.

Angiography↗
PubMed1975

Demineralization of bone matrix: observations from electron microscope and electron-probe analysis.

Displacement or removal of mineral during the processing of calcified tissues for electron microscopy is a recognized phenomenon. An electron microscope analysis has been made of artefactual mineral loss during ultramicrotomy of osteogenic tissue. It is concluded from morphological investigation and the use of electron diffraction that this loss of crystalline mineral during sectioning can considerably change the morphology of calcified tissues and may lead to inaccurate interpretation of cell and matrix morphology. Electron probe X-ray microanalysis has been used to demonstrate in a semi-quantitative manner, the artefactual loss of calcium and phosphorus. Problems of specimen preparation for such analytical work are discussed.

Animals↗
PubMed1975

Frozen thin-sections of rapidly forming bone: bone cell ultrastructure.

Frozen thin-sections of fresh medullary bone, which had been calcifying for 2 to 4 days, were prepared and examined in the electron microscope. The bone was obtained from male Japanese quail treated with estradiol valerate. Large numbers of 200-800 A electron dense granules, which consisted of 50-75 A subparticles, were seen within mitochondria. A population of electron-dense particles slightly smaller than ribosomes was also observed. Most granules were not present after conventional fixation, dehydration, embedding, sectioning and staining. Oother structures which were visible, also on the basis of their intrinsic electron density, were nuclei with regions which resembled condensed chromatin, ribosomes and rough endoplasmic reticulum. By the use of osmium tetroxide vapor staining, inner and outer membranes and cristae of mitochondria were delineated. Other membranous components were not detected. Since very little loss or dislocation of cell components can occur during the preparation of frozen thin-sections, the micrographs obtained may be a more accurate representation of cell ultrastructure.

Animals↗
PubMed1990

A highly efficient method for staining ultrathin sections.

A simple and efficient staining method to handle simultaneously thirty (or even more) electron microscope grids with ultrathin sections is described. The device applied is easily constructed from inexpensive and readily available materials but can bring easily high quality staining results, and the amount of stain and washing water required is very small.

Microscopy, Electron↗
PubMed1988

Visualization of fungi in histological sections.

Deparaffinized kidney sections from mice infected with Candida albicans and lung sections from mice infected with Blastomyces dermatitides were stained with the stilbene derivative, Uvitex 2B (1%), and counterstained with haemalum and eosin. Fungi selectively stained with Uvitex 2B are visualized by blue fluorescence under incident illumination with ultraviolet light. Simultaneous or consecutive illumination with transmitted light permits the assignment of fluorescent fungi to haemalum-eosin-stained structures in the section. The most practical means of achieving a high optical contrast with Uvitex 2B in sections and good haemalum-eosin staining is to use the established haemalum-eosin technique, but with a solution containing both 1% eosin and 1% Uvitex 2B in place of eosin alone. Since Uvitex 2B stains all fungi investigated so far, it affords a simple, sensitive and inexpensive method of selectively detecting opportunistic fungal infections in conventional histopathology.

Animals↗
PubMed1991

Histogenesis of diisopropanolnitrosamine (DIPN)-induced tumors of the rat thyroid gland.

In an attempt to eludicate the histogenesis of thyroid carcinoma, histopathological and immunohistological studies were conducted on rat thyroid tumors induced by diisopropanolnitrosamine (DIPN). A total of 235 nodular lesions detected on serial sections of whole thyroid glands were classified into three types as follows: foci of cellular alteration at the single follicle level (type 1); multifollicular nodules considered to be malignant or potentially malignant (type 3); and multifollicular, proliferative nodules other than type 3, including both hyperplastic and neoplastic nodules (type 2). Analysis of the frequency of nodular lesions after various periods of time following exposure to DIPN revealed that the size of the nodules, their pattern of development, and their growth activity, as measured by the labeling index for bromodeoxyuridine (BrdU), showed sequential changes. Type 1 lesions appeared early; these lesions were the smallest and were considered to indicate the initial morphological change. Subsequently, type 2 nodules of intermediate size and labeling index, and finally type 3 nodules with the largest size and the highest labeling index developed; the latter type 3 nodules become more numerous during the latest phase following DIPN exposure. These observations support a multistage hypothesis of tumorigenesis.

Animals↗
PubMed2004

Ideal cooling process for paraffin-embedded tissues.

Back in the seventies everybody was convinced that it was no longer necessary to cool paraffinembedded tissues, because of the new advances in the production of paraffin. The reason for this assumption was the addition of plastic polymers and dimethyl sulfoxide. The quality of tissue sectioning improved because of these additives. The daily routine in the histology laboratories shows that it is impossible to produce good quality cutting without cooling. Cooling the paraffin by means of cooling plates or ice dishes creates drastic improvement; the cutting quality improves and it is much easier. Both improvements speed up the process and save time for the technicians and the physician. Long-term study indicates that not only the temperature but also the methodology of cooling and the cooling rate are playing a decisive role in the cutting quality.

Cold Temperature↗