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At least 37 records · Page 2Linked to original sources
PubMed1978

Substructure of inner mitochondrial membranes of myocardial cells as shown by cryo-ultramicrotomy.

The substructure of the inner mitochondrial membranes has been studied by cryo-ultramicrotomy under conditions during which denaturation of proteins by treatment with chemical solutes has been totally avoided. In such preparations, the inner membrane has a substructure consisting of globular subunits. These subunits have an average diameter of ca. 20 A-ca. 62 A and are fairly regularly spaced. Intracristal space is absent in the unstained, freeze-dried preparations, whereas a space of ca 40 A is seen in preparations lightly treated by OsO4-vapour. It is concluded that the subunits of the inner mitochondrial membranes probably consist either of single protein molecules or of complexes of protein molecules.

Animals↗
PubMed1977

Electron microprobe investigations into the process of hard tissue formation.

The electron microprobe microanalyser has been used to measure the concentrations of Ca, P and S in the predentine of young rat incisors. The specimens were prepared as alcohol embedded ultrathin sections, unfixed vacuum embedded dry cut ultrathin sections and as thin cryostat sections. The results show the influence of preparation on the measured compositions and indicate that Ca is tightly bound to the matrix, whereas P can be easily washed out. Measurements along the dentine-predentine border demonstrated zones of Ca enrichment, the average size of which suggests that the zones could be the prestages of calcospherites. A mineralisation mechanism is discussed in which the high Ca concentration activates pyrophosphosphatase or ATPase before the onset of nucleation.

Animals↗
PubMed1975

Tubular structures associated with intracytoplasmic spirochetes.

When tissues of spirochete-infected brine shrimp (Artemia salina) were examined by electron microscopy, tubular structures were often seen closely associated with intracytoplasmic spirochete profiles. These tubules were never observed in association with spirochetes found in the haemocoeal or other extracellular spaces. Since the trilaminar layer comprising the wall of the tubules was identical in ultrastructure to the outer envelope of the spirochete, these structures were interpreted to be finger-like extensions of the spirochete outer envelope.

Animals↗
PubMed1992

A new histological embedding method by low-temperature polymerisation of methyl methacrylate allowing immuno- and enzyme histochemical studies on semi-thin sections of undecalcified bone marrow biopsies.

A new procedure of embedding in methyl methacrylate (MMA) is introduced, which enables immunostaining by preservation of cellular epitopes. This could be achieved by reduction of polymerisation temperature from ca. 60 degrees C to 22 degrees C within the core of tissue blocks. Reduction of the polymerisation temperature is due to destabilisation of acrylate monomer, reduction of catalyst, exclusion of molecular oxygen, chemical initiation and reduction of environmental temperature. This results in good preservation of antigens and enzymes in the haematopoietic and lymphatic tissue of bone marrow as well as lymphoid, epithelial and mesenchymal markers in other tissues, comparable to paraffin embedding. Results are demonstrated by application of monoclonal and polyclonal antibodies and by demonstration of enzyme activity conventionally used in haematology.

Biopsy↗
PubMed1975

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↗
PubMed1977

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↗
PubMed1977

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↗
PubMed1977

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↗
PubMed1976

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↗
PubMed1975

Observations on the selective demonstration of nucleolar material by protein staining techniques in epon thick sections.

The effect of different protein stainings on thick sections of Epon embedded salivary glands of Chironomus pallidivittatus is described. Pretreatment of sections with several metallic salts affected the affinity for aniline blue black in different structures. The uranyl and aluminium ions followed by aniline blue black resulted in a highly selective nucleolar staining which proved also efficient in Allium cepa meristematic cells and which seems useful for the preferential demonstration of nucleolar material in thick sections.

Animals↗
PubMed1975

[Determination of intracapillary HbO2 saturation with a cryo-microphotometric method, applied to the rabbit myocardium (author's transl)].

We succeeded in determining the O2 saturation of Hb in capillaries of the rabbit myocardium with a cryo-microphotometric method. Myocardial samples (2-3 mm) were removed in situ with a pair of nitrogin-cooled copper tongs, and rapidly frozen in Freon 13. The samples were sectioned into 10-12 mum slices in a cryotome at about minus 60 degrees C. Hemoglobin absorption spectra were measured on the capillary sections of the frozen slices at minus 100 degrees C in a vacumm-isolated microscope cooling chamber which we developed for the UMSP 1 (C. Zeiss, Oberkochen). The spectra were subdivided into three basic components (oxygenated Hb, desoxygenated Gb, and desoxygenated dehydrated Hb) with a weighted multi-component analysis (Lübbers and Wodick, 1969). The basic components were measured in Hb solutions. The accuracy of the method was tested both with Hb solutions inserted into glass capillaries, and Hb droplets. O2 saturations of the Hb solutions were measured at room temperature. Subsequently, both test solutions were frozen, HbO2 saturation measured in the glass capillaries at low temperatures agreed well with those recorded at room temperature. HbO2 saturation of the sectioned hemoglobin droplets was found to be systematically increased with low Hb32 saturations as compared with the records made at room temperature. The systematic error was determined and the intracapillary HbO2 saturations were corrected accordingly. Measurements on samples of the rabbit myocardium showed that the histogram of capillary HbO2 saturations has a maximum at saturations of 20-30%. The lowest saturation values were found to be between 0 and 10%, but these values were recorded less frequently. The arterial HbO2 saturation in the femoral artery was about 98%.

Animals↗
PubMed1978

Thickness measurements of skeletal muscle sections using the light microscope.

A new device is described for improving the accuracy of measuring the thickness of cryostat sections by the focusing technique in the light microscope. The necessity of such measurements is demonstrated by the great variation (range 2.55 micrometer--11.93 micrometer) in the thickness of serial cross-sections of frozen muscle biopsies from 12 healthy men. The final dehydration of the sections was found to reduce the thickenss of fresh sections by 47%. However, dehydration caused the cross-sectional area to be reduced by only 2.8%.

Adenosine Triphosphatases↗
PubMed1978

Fine structural analysis of the morphological changes involved in the blanching, cooking, dehydration and rehydration of green bean pod tissue.

The influence of blanching and cooking on green bean pod tissue (Phaseolus vulgaris var.nanus L.) was studied by transmission electron microscopy and characteristic histological and cytological effects were recorded. The analysis of dehydraded and rehydrated samples (dehydration by hot air, rehydration by boiling) showed that much of the shrinkage after dehydration can be compensated by water absorption during rehydration. The morphological appearance of boiled raw tissue, however, is not reached.

Cooking↗