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Biomedical subjects

W T Daems

Publications and source records attributed to W T Daems.

At least 73 records · Page 4Linked to original sources
PubMed1978

Are Langhans giant cells precursors of foreign-body giant cells?

Granulomas were induced in rats by subcutaneous implantation of pieces of Melinex plastic into the dorsum. The pieces of Melinex were removed at intervals varying from 16h to 14 days, and the adherent cells were studied morphologically and quantitatively. Giant cell formation started about 32h after implantation. The first giant cells to appear were of the Langerhans type. Two days after implantation, most of the giant cells are still Langhans-type cells. A few giant cells of the foreign-body type and transition forms between the Langhans and foreign-body types are also present. From the third day on, the foreign-body type gradually becomes predominant. Independent of the duration of implantation, giant cells with 3, 4, or 5 nuclei are virtually without exception of the Langhans type. The higher the number of nuclei between 6 and 30, the more cells are of the foreign-body type. Giant cells with 30 or more nuclei are all foreign-body type. The findings are discussed in the light of current knowledge concerning giant cell formation. It is concluded that under the present experimental conditions, Langhans-type giant cells are the precursors of foreign-body-type giant cells.

Animals↗
PubMed1978

The effects of various stimuli on the cellular composition of peritoneal exudates in the mouse.

A comparative study on the composition of cell populations collected from the unstimulated mouse peritoneal cavity and at various intervals after the intraperitoneal injection of glycerol trioleate, casein, paraffin oil, glycogen, sodium chloride, and proteose peptone, was carried out. The cellular composition of the peritoneal exudates, especially with respect to the ratio of monocytes to resident macrophages, was shown to be dependent on the nature of the stimulus and interval after stimulation.

Animals↗
PubMed1978

Peroxidase activity in monocytes and tissue macrophages of mice.

A description is given of the distribution of peroxidatic (PO) activity in murine monocytes of blood and peritoneal cavity, and in murine macrophages residing in the unstimulated peritoneal cavity as well as in liver, spleen, bone marrow, and small intestine. In the monocytes, PO activity is restricted to some of the cytoplasmic granules; in the tissue (or resident) macrophages present in peritoneal cavity, liver, spleen, and small intestine, the PO activity is located in the nuclear envelope and the rough endoplasmic reticulum. Macrophages in the bone marrow are PO-negative. In the spleen and bone marrow, reticulum cells show PO activity in the nuclear envelope and the RER. Transitional forms between monocytes and tissue macrophages were not observed.

Animals↗
PubMed1978

A new dynamic model system for the study of capture reactions for diffusable compounds in cytochemistry. I. Description of the model with special attention to phosphate capture in acid phosphatase cytochemistry.

A model system is described for the investigation of the dynamics of precipitation processes in a matrix. In this system a solution containing the molecular species to be precipitated and the precipitating medium are pumped along opposite sides of a polyacrylamide film. The solutions flowing continuously along the film, interact and can form a precipitate inside the film. The applicability of the model was tested on the capture reaction for phosphate ions by the Gomori type medium for acid phosphatase. Precipitation of lead phosphate in the film occurred only at a phosphate concentration above a certain value. The dependence of this minimal phosphate concentration on various parameters was studied and the results were compared with values found in earlier model studies and calculations concerning phosphate concentrations that can be built up in lysosomes during the Gomori reaction. The system seems promising for obtaining fundamental data about other cytochemical enzyme trapping reactions as well as for the matrix facotrs involved in bone calcification and shell formation.

Acid Phosphatase↗
PubMed1978

Are Langhans giant cells precursors of foreign-body giant cells?

Granulomas were induced in rats by subcutaneous implantation of pieces of Melinex plastic into the dorsum. The pieces of Melinex were removed at intervals varying from 16 h to 14 days, and the adherent cells were studied morphologically and quantitatively. Giant cell formation started about 32 h after implantation. The first giant cells to appear were of the Langhans type. Two days after implantation, most of the giant cells are still Langhans-type cells. A few giant cells of the foreign-body type and transition forms between the Langhans and foreign-body types are also present. From the third day on, the foreign-body type gradually becomes predominant. Independent of the duration of implantation, giant cells with 3, 4, or 5 nuclei are virtually without exception of the Langhans type. The higher the number of nuclei between 6 and 30, the more cells are of the foreign-body type. Giant cells with 30 or more nuclei are all foreign-body type. The findings are discussed in the light of current knowledge concerning giant cell formation. It is concluded that under the present experimental conditions, Langhans-type giant cells are the precursors of foreign-body-type giant cells.

Animals↗
PubMed1978

Accumulation and localization of gallium-67 in various types of primary lung carcinoma.

The uptake and location of Ga-67 were investigated in 15 primary pulmonary carcinomas. The accumulation in the tumor was determined by scintigraphy of the patient, grain counts over fields of tumor cells in autoradiographs of tumor-tissue samples, and gamma counts in specimens of the tumor. Good correlation was found between the results obtained with these three methods. The relationship between accumulation of Ga-67 in the tumor and the histologic type of tumor was also studied. Undifferentiated carcinomas, and tumor cells in squamous-cell carcinomas showed significantly more Ga-67 than tumor cells in adenocarcinomas. No correlation was found between the presence of inflammatory infiltrates in or around the tumor and the grade of the scintigraphic images. In the autoradiograms, lymphocytes, plasma cells, granulocytes, and macrophages showed less radioactivity than the tumor cells--or none at all. Collagen fibers appeared to have bound some Ga-67, but necrotic areas showed no uptake.

Aged↗
PubMed1977

Fine structure and peroxidatic activity of rat blood monocytes.

Rat blood monocytes contain granules of two types, primary and secondary granules, which can be distinguished on morphological grounds. Secondary granules have a halo between the limiting membrane and the matrix; primary granules have no halo and are generally more elongate than the secondary granules. In addition, there are differences in the distribution of the diameters of these two types of granules. The cytochemical characteristics of the peroxidatic activity of these granules were investigated by using different prefixation conditions in combination with a number of DAB media differing in pH and H2O2 concentration. Prolongation of the prefixation and increasing the pH of the incubation medium increased the staining intensity of the secondary granules and decreased the staining intensity of the primary granules. In unfixed cells peroxidatic activity could be demonstrated only in the primary granules. It is concluded from the present findings that peroxidase occurs in primary granules and not in secondary granules, whereas catalase is present in secondary granules but probably not in primary granules. No evidence was found for the presence of microperoxisomes in rat blood monocytes.

Animals↗
PubMed1977

Qualitative and quantitative preservation of the fine structure of absorptive cells in cultured biopsies of human small-intestine.

The fine structure of the absorptive cells in human small-intestinal biopsies cultured for 6, 24, and 48 h was analyzed qualitatively and quantitatively. The findings show generally good preservation of the cultured absorptive cells and a normal distribution, size, and relative volume of their cell organelles, but there was a systematic decrease in the apical cell surface and an increase in the number of apical vesicles and tubules after culturing. Since the apical vesicles and tubules are thought to have a function in the transport of cell-coat material from the Golgi apparatus to the cell surface, these findings raise the question of whether a delayed transport or extrusion of cell surface material occurs. The diminished relative volume of the mitochondria and the increased signs of autophagy in some poorly preserved absorptive cells, are assumed to be an adaption to less favourable culture conditions.

Biopsy↗
PubMed1977

A new type of primary granule in guinea pig heterophil granulocytes.

Guinea pig heterophil granulocytes were found to have three types of granules which are formed sequentially during the development of the cells in the bone marrow and differ in shape and electron density: nucleated, azurophil and specific granules. Early promyelocytes proved to synthesize nucleated granules of medium electron density prior to the formation of azurophil granules which are highly electron dense, by late promyelocytes. Since the formation of nucleated granules and azurophil granules is restricted to promyelocytes, both can be considered to be primary granules. The moderately dense specific granules (secondary granules) appear later during granulopoiesis and are firstly present in the myelocyte.

Animals↗
PubMed1976

The relation between cell proliferation, differentiation and ultrastructural development in rat intestinal epithelium.

The ultrastructural development of the principal cells in rat small intestine was studied by morphometric analyses in relation to the exact cell position along crypt and villus. From the bottom to the tip of the crypt, a gradual increase occurred in absolute size of the total cell, the cytoplasm, the terminal web and of nearly all cell organelles. Also, the relative size of the cytoplasm, mitochondria, microvilli and endoplasmic reticulum increased during crypt cell differentiation. No sudden changes in ultrastructure were observed in the so-called "critical decision zone", normally located halfway up the crypt where the proliferative activity ceases. At the crypt-villous junction a 1.4-3 fold increase in cell size, cytoplasm, terminal web and of most organelles was noted. Expansion of the proliferative cell compartment over the total length of the crypt as occurs during recovery after a low X-irradiation dose (72 h after 400 R) does not affect the normal development of cellular ultrastructure. These findings are discussed in relation to biochemical and cell kinetic data.

Animals↗
PubMed1976

The pit cell: description of a new type of cell occurring in rat liver sinusoids and peripheral blood.

Pit cells--a new type of cell first described here and so named because they contain highly characteristic granules--are situated in the wall of rat liver sinusoids, and have hyaloplasmic pseudopodia intermingling with the microvilli of the parenchymal cells. The characteristic granules are mainly situated at one side of the nucleus, the other side showing organelle-free hyaloplasm. Pit cells are also found in portal tracts and in granuloma-like cellular aggregates. They also occur in rat peripheral blood, although there are morphological differences between cells in these two sites. Pit cells can be regarded as regular inhabitants of the sinusoidal wall, and therefore belong to the series of sinusoidal cells, i.e., the endothelial (Wisse, 1972), Kupffer (Widmann et al., 1972; Wisse and Daems, 1970; Wisse, 1974a, b), and fat-storing cells (Ito, 1973). Pit cells do not phagocytose and do not react to a great number of experimental conditions, to which endothelial and Kupffer cells do react (Wisse, 1972, 1974b). Mitosis has been observed in a pit cell. The function of pit cells remains obscure, but an endocrine function is suggested by the morphology of their highly characteristic granules.

Animals↗
PubMed1976

Cytochemical model system for microsomal rat liver glucose-6-phosphate.

A method is described for the incorporation of a microsomal rat liver fraction into polyacrylamide films without significant loss of its glucose-6-phosphatase activity. The enzymatic activity was completely lost when the films were prepared with ammonium persulfate as initiator of the polymerization as previously described for alkaline phosphatase, but modification of this method showed that about 90% of the glucose-6-phosphatase activity could be retained. The enzyme in the films prepared with the new method was completely inhibited by alloxan, HgCl2, and preincubation in 0.05 M acetate buffer (pH 5.0) at 37 degrees C, as determined biochemically. Similar results were obtained for the enzyme in films determined histochemically according to the lead method of Wachstein and Meisel. In this respect the behavior of the incorporated enzyme is similar to that in suspension. Films fixed with 1.5% glutaraldehyde showed rapid inactivation of glucose-6-phosphatase. There was good correlation between the biochemical and histochemical activity determined after fixation. A method to embed polyacrylamide films in Epon for electron-microscopical investigation is also described. Dimethyl sulfoxide was used as the dehydrating agent instead of ethanol/acetone.

Acrylamides↗