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At least 613 records · Page 34Linked to original sources

A method for determining reference points in celloidin specimens for computer graphic reconstruction.

For three-dimensional computer graphic reconstruction of histological sections, it is important to determine reference points. We have developed a machine that makes reference points in a celloidin block for this purpose by drilling holes straight into the block. A sliding microtome is placed under the machine, which consists of a worktable, a stand, and a motor-driven unit. The celloidin block is sectioned on a microtome to determine a plane for serial sectioning. Several holes are then drilled in the block vertical to the plane selected. Serially sectioned specimens are next stained with hematoxylin and eosin and are mounted in the usual manner. Three-dimensional reconstructions of the specimens were next done using a PC-9801 computer and CosmoZone-S software. As an example, the reconstruction of a guinea pig stapes is described.

Animals↗

Histochemical and X-ray microanalytical investigations of defined organs and cells in their true position within whole-body cryosections.

Large cryosections (up to 45 x 15 cm) have been made from an entire rat or hamster or from a large human organ such as a cross section of a leg obtained from amputation operations. The quality of the sections was found to be sufficient for a histochemical and a X-ray microanalytical characterization of individual cells in the tissues of interest. When histochemical stainings were applied on sections from a human leg, different muscle groups were analysed simultaneously for pathological changes and at the same time bone tissue, nerves and blood vessels could be investigated. It was possible to study pathological changes in relation to histochemical muscle fibre type and describe the dispersion of changes within a certain muscle. Analytical scanning electron microscopy (X-ray microanalysis) was useful for the description of the elemental composition of different organs on longitudinal sections of small animals and of different muscle fibres in the leg cross sections. The X-ray emission could be related to histochemical muscle fibre type and other parameters such as the degree of fibre atrophy.

Animals↗

Studies on 5'-nucleotidase histochemistry. III. 5'-Nucleotidase activity in smooth muscle cells of the rat's gastrointestinal tube.

The distribution pattern of histochemically detectable 5'-nucleotidase (5'-Nase) activity is described in smooth muscle cells of the rat's gastrointestinal tube (esophagus, stomach, small intestine, large intestine). Both, light and electron microscopic methods are used. Faint positive 5'-Nase activity is observed on smooth muscle cells of the lamina muscularis mucosae in the thoracal esophagus whereas it is completely absent from smooth muscle cells of the abdominal esophagus and the stomach. In the small and large intestine strong positive 5'-Nase reaction is found on smooth muscle cells of the lamina muscularis mucosae and the innermost part of the lamina muscularis externa. In the circular and longitudinal layer of the lamina muscularis externa a slight increase in 5'-Nase activity is observed from the proximal to the distal segments. The reaction product is restricted to the outer cell surface of smooth muscle cells. In the small intestine the strong enzymatic activity in the innermost part of the muscularis externa is found to be localized at small and dense muscle cells (sd-cells). Common morphological and histochemical characteristics of sd-cells and smooth muscle cells of the lamina muscularis mucosae are emphasized. Hypothetical functions e.g. uptake of precursors of nucleosidephosphates, possible functional connection to a high glycogen content, correlation between 5'-Nase activity and proliferation capacity and local vasodilatory effect are discussed.

Adenosine Diphosphate↗

Combined visualization of central catecholamine- and acetylcholinesterase-containing neurons: application of the glyoxylic acid and thiocholine histochemical methods to the same Vibratome section.

This paper describes a procedure for demonstration of catecholamine- and acetylcholinesterase-containing neurons in the same section of central nervous tissue. The brains are first processed according to the glyoxylic acid (GA) fluorescence method for catecholamine neurons, i.e. perfused with an ice-cold GA solution, sectioned on a Vibratome instrument, immersed in a GA solution and dried under a stream of warm air. The unmounted sections are examined and photographed in the fluorescence microscope, and then stained for acetylcholinesterse according to Holmstedt's modification of the Koelle thiocholine method (incubation for 4-6 h with acetylthiocholine as substrate and Mipafox as inhibitor of non-specific cholinesterases). the sections are then examined in the light microscope, rephotographed, and the picture compared with that following the GA reaction. The present technique makes possible, for the first time, detailed light microscopical studies of themorphological relations between central catecholamine-and acetylcholinesterase-containing neurons in the same section.

Acetylcholinesterase↗

Bone alkaline phosphatase kinetics studied by a new method.

Studies of enzyme kinetics by histochemical methods has been seriously impaired by available methods. This study combines two newer methods, i.e., sectioning undecalcified bone from glycol methacrylate and the use of atomic absorpton spectrophotometry for photographic densitometry. The results indicate that the substrate concentration for zero order kinetics of the alkaline phosphatase reaction in bone is 0.5 mg/ml of substrate; and the Km of the same reaction is estimated to be 0.25 mg/ml or 0.56 mM of substrate.

Alkaline Phosphatase↗

A new integrated concept for the improved preparation of sections of fresh or frozen tissue for light microscope histochemistry.

In order to obtain thin sections of plant tissues which combined good morphological preservation and the preservation of the substances and enzyme activities in the tissues, a concept of section preparation by external stabilization was developed. The main components are as follows: appropriate supporting medium; surface coating before each sectioning process, the coating being either non-permanent, permanent, or semi-permanent; suitable techniques for affixing the coated sections to the slides using either pressure-sensitive adhesive or solvent-based adhesive; and mounting media with defined refractive indices (preferably UV-curable, water-soluble monomers). By this approach, sections exhibiting excellent morphological and physiological preservation were obtained using either a cryostat at -30 degrees C or a rotary microtome at room temperature.

Adhesives↗

Effect of tissue processing on the immunostaining of inflammatory cell surface epitopes identified by monoclonal antibodies.

Optimal tissue processing conditions were defined for the immunohistochemical detection of inflammatory cell surface epitopes identified by OKT3, OKT4, OKT6, OKT8, OKIa1, OKM1, Leu7 and pan B cell antibodies. Snap-freezing in isopentan was superior to liquid nitrogen in preservation of morphology. Embedding of the tissues in Tissue-Tek II O.C.T. Compound diminished the intensity of immunostaining with all antibodies studied; however, the embedded tissues tolerated longer storage without drying. Optimal fixation with satisfactory preservation of morphology and immunogenicity was achieved with fixation of the frozen sections in acetone at 4 degrees C for 5 min. Blocking of the endogenous peroxidase with methanol-H2O2 treatment destroyed all epitopes studied except those identified with OKIa1, OKT6 and Leu7.

Antibodies, Monoclonal↗

Conditions for the immunohistochemical demonstration of complement factor C3 in formaldehyde-fixed and paraffin-embedded renal tissues.

Paraffin sections of formaldehyde-fixed renal biopsies were labeled for complement C3 by a polyclonal rabbit antibody to human complement C3, by the peroxidase-antiperoxidase complex (PAP) and the avidin-biotin peroxidase complex (ABC) techniques, respectively. All tissues had C3 deposits according to direct immunofluorescence on fresh frozen sections. Staining for muramidase was introduced as an intrinsic control for the degree of tissue proteolysis after the necessary trypsin digestion prior to the immunoenzyme labeling. The results indicated that even minute deposits of C3 could be detected in paraffin sections by the ABC method, which was more sensitive than the PAP technique; the ABC method allowed a maximal dilution of 1:2,400 of the primary antibody as compared to 1:800 for the PAP technique.

Animals↗

The influence of freezing and freeze-drying of tissue specimens on enzyme activity.

In the presented study the influence of freezing and freeze-drying on enzyme activity is described. Attention is paid to 16 enzymes which can be used for quantitative enzyme histochemical techniques. With the exception of succinate dehydrogenase only, no significant inactivation during freezing and freeze-drying procedures could be demonstrated with lactate dehydrogenase, malate dehydrogenase (NAD+), malate dehydrogenase (decarboxylating) (NADP+), isocitrate dehydrogenase (NADP+), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, NADH-oxydoreductase, mitochondrial glycerol-3-phosphate dehydrogenase, cytochrome c oxidase, phosphoglucomutase, glucosephosphate isomerase, glucose-6-phosphatase, acid phosphatase, beta-glucuronidase and non specific aryl esterase. Therefore, the results supply a sound foundation for those quantitative enzyme histochemical techniques in which tissue specimens are frozen or frozen-dried before enzyme estimations are performed.

Animals↗

The influence of tissue section thickness on the study of collagen by the Picrosirius-polarization method.

The influence of tissue section thickness on the color and intensity of birefringence displayed by collagen in tissue sections studied by means of the Picrosirius-polarization method, is reported in this paper. When dermal collagen sections of different thicknesses (ranging from 0.25 to 11 micrometers) were studied by this method, it became evident that not only did the intensity of birefringence increase proportionally to tissue section thickness, as was to be expected, but also a gradual shift in color from green through a yellow to red could be observed as tissue section thickness increased. The limitations of the Picrosirius-polarization method for the localization of collagen types I, II, and III in routinely used histological slides is discussed, showing that this method is useful for the study of the distribution of the different types of interstitial collagen in normal adult vertebrate organs.

Animals↗

The use of ultrathin cryosections for localisation of influenza virus antigens in infected vero cell cultures.

The localisation of influenza virus antigens in infected Vero cell monolayer cultures by post embedding immunoelectron microscopy requires both good resolution and the retention of antigenicity in the tissue sections. Ultrathin cryosections are superior to ultrathin resin sections for this purpose. The colloidal gold probe was used in conjunction with specific antibody preparations to localise three viral proteins. Antibody raised against haemagglutinin glycoproteins labelled the host cell membrane and the virus fringe without contamination of the host cell nucleus, whereas antibody raised against viral nuclear protein labelled throughout the host cell cytoplasm and nucleus. Matrix protein was localised within the nucleus and was associated with the host cell membrane of the infected cell. The appearance of all these proteins was maximal 24 h post infection.

Animals↗

A method for studying glyoxylic acid induced fluorescence and ultrastructure of monoamine neurons.

Inasmuch as precise correlations of light- and electronmicroscopy are crucial for understanding biostructure, it seemed necessary to bring together the advantages of the glyoxylic acid (GA) method (for inducing monoamine fluorescence) and electron microscopy. A combined fluorescence and electron microscope method using GA is introduced. The brain is perfused by 2% GA in Krebs-Ringer bicarbonate buffer (pH 7.0) and this solution is followed by 4% paraformaldehyde containing 0.5% glutaraldehyde in Sorensen's phosphate buffer (pH 7.4). Sections are cut by cryostat or by vitratome and incubated in 2% GA in phosphate buffer (pH 7.0). Using fluorescence microscopy, features of interest are sketched and/or photographed. Afterwards, the same or subsequent section is processed for electron microscopy. Since axons of catecholamine-containing neurons (as well as their perikarya and terminals) are visualized by GA, the recommended procedure expands the range of studies concerning monoamine neurons that can now be carried out effectively.

Animals↗