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Biomedical subjects

T A Ryder

Publications and source records attributed to T A Ryder.

54 records · Page 3Linked to original sources
PubMed1978

Obstructive azoospermia: respiratory function tests, electron microscopy and the results of surgery.

Forty-five patients have been treated surgically for obstructive azoospermia. Fifteen underwent reversal of vasectomy and 40% of the wives became pregnant. Thirty had epididymovasostomy, and in only 2 (6.5%) did the sperm count become normal, although a few poorly motile sperms appeared in the ejaculate in a further 4 patients. Congenital abnormalities of the vasa in 7 cases and post-inflammatory blocks in 4 cases were examples of obstructive azoospermia due to well defined causes. However, in half of the patients (15 cases) the cause was obscure although it was associated with sinusitis, bronchitis or bronchiectasis (Young's syndrome). The results of pulmonary function tests in 30 cases, and electron microscopic studies of cilia from epididymes (10 cases) and bronchial mucosa (2 cases) indicated that the basic abnormality might be malfunction of the microtubules which appeared to be ultrastructurally normal in most cases. One case appeared to be associated with dietary deficiency, and correction of diet coincided with a successful result of surgery.

Adult↗
PubMed1977

Studies on transmembrane and paracellular phenomena in the foot of the slug agriolimax reticulatus (Mü).

Using the enzyme peroxidase and ionic lanthanum as tracers, paracellular uptake has been demonstrated in the foot of the slug Agriolimax reticulatus (Mü). Both tracers appeared to pass between adjacent foot epithelial cells and were demonstrated in the zonula adhaerens, the septate desmosomes, and the intercellular spaces which occur beneath the septate junctions. Ferritin, a somewhat larger tracer, was excluded from all these sites. Ionic lanthanum was not normally pinocytosed in short incubation times. The epithelial cells could be induced to endocytose this marker, however, when combined with a variety of proteins. The implications these findings have on the uptake of molluscicides is discussed.

Animals↗
PubMed1977

Endocytosis and aspects of autophagy in the foot epithelium of the slug Agriolimax reticulatus (Müller).

The foot epithelium of the slug Agriolimax reticulatus (M) can function as a digestive epithelium and possesses a vacuolar system in which heterophagic and autophagic material is hydrolysed. Using ferritin and peroxidase as markers, the process of endocytosis has been demonstrated at the level of the electron microscopy. The mechanisms involved with the uptake of each marker differed in that ferritin was confined to fairly large vacuoles, while peroxidase was present in smaller pinocytotic vesicles which ultimately fused to form larger vacuoles or multivesicular bodies. Cytochemical tests for acid phosphatase revealed that the latter bodies acquired hydrolytic enzyme to become secondary lysosomes. Acid phosphatase was also localized in the Golgi apparatus of the epithelial cells. In addition to the endocytotic activity, evidence of autophagy was found in the epithelial cells and this process was apparently enhanced during starvation.

Acid Phosphatase↗
PubMed1977

The use of X-ray microanalysis to demonstrate the uptake of the molluscicide copper sulphate by slug eggs.

Copper has been localized in copper sulphate treated eggs of the slug Agriolimax reticulatus (Mü). This has been accomplished using a freeze-fracture technique, the freeze-dried halves of the fractured eggs being analysed in the scanning electron microscope, using both energy dispersive and wavelength dispersive X-ray microanalysis systems. The distribution of copper obtained using these methods has been compared with that achieved using a standard histochemical technique. Both techniques revealed that the copper is initially retained in the perivitelline membranes. The application of X-ray microanalysis to such studies is discussed.

Animals↗
PubMed1976

An X-ray microanalytical azo dye technique for the localization of acid phosphatase activity.

A new method is described for the histochemical localization of acid phosphatase. Naphthol AS BI, enzymatically released from naphthyl AS BI phosphoric acid, is coupled with diazotized 2,5-dibromoaniline to produce a fine insoluble red azo dye. The histochemical and cytochemical localization of this final reaction product in rat liver is described. In the electron microscope, sites of the azo dye can be detected by X-ray microanalysis of ultrathin cryosections of reactive tissue.

Acid Phosphatase↗
PubMed1976

The effects of starvation on the planarian worm Polycelis tenuis Iijima.

Employing a combination of microscopical, biochemical and autoradiographic techniques, the primary effects of starvation on adult polycelis tenuis have been studied. Over a five week period of starvation there is on average a 32% decrease in the size of the organism. This decrease is contributed to by a reduction in mitosis and an increase in cell shrinkage autolysis and death. During starvation (following a sharp rise in RNA synthesis) there is a distinct sequence of events; four peaks of acid phosphatase activity can be resolved. The first is associated with the immediate response of the gastrodermis to feeding; the second (after 6 to 7 days) with increased autophagy and dedifferentiation in the gland cells and with muscle lysis of cells. The third peak (after 14 to 15 days) is contributed to largely by the lysis of cells in the gut and the fourth peak (after 25 to 26 days) is caused by an extensive lysis of the reproductive system. Fine structural changes involving increased intracellular vacuolation, autophagy, crinophagy, atrophy of muscle, increased intercellular space and loss of basement membrane matrix have been related to changes in enzyme pattern. Nerve cells appear unchanged throughout the first five weeks of starvation. Pigment and gland cells loose their characteristic granules, dedifferentiate and become morphologically similar to the undifferentiatied neoblasts. Dedifferentiation and the mechanisms involved in the survival of starvation are discussed.

Acid Phosphatase↗
PubMed1976

Use of the p-nitrophenyl phosphate method for the demonstration of acid phosphatase during starvation and cell autolysis in the planarian Polycelis tenuis Iijima.

Acid phosphatase activity is demonstrated employing p-nitrophenyl phosphate as substrate and lead acetate as coupler. The fine structural localization of the enzyme in starved planarian tissues is described. The method is used to pin-point starvation - induced acid phosphatase activity in relation to autophagy and crinophagy in the gland cells; autophagy, autolysis and cell death in parenchymal and gastrodermal cells and basement membrane lysis. Attention is also payed to the demonstration of muscle lysis. The histochemical implications of the method are discussed.

4-Nitrophenylphosphatase↗
PubMed1975

The distribution of oxidizable mucosubstances and polysaccharides in the planarian Polycelis tenuis Iijima.

A chromic acid oxidation-silver technique was used to localize polysaccharide material in Polycelis tenuis at the electron microscope level. In the epithelium, staining was observed within apical vacuoles and on the free surfaces of the cells. A similar staining was observed in relation to the glycocalyx of the pharyngeal epithelia and that of the flame cells. Silver was deposited in the basement membrane. In the parenchyma, the major components giving a positive reaction were the cyanophil and mucous gland cells. Particularly strong silver staining (confirmed by X-ray microanalysis) was observed in the granules and Golgi apparatus of the cyanophil cells. IDPase activity was also found in relation to the Golgi apparatus and its secretory products. The overall distribution of mucopolysaccharide material was confirmed with the PAS and Alcian blue techniques. The fine structural localization of the Alcian blue was also determined using electron microscopy and X-ray microanalysis.

Animals↗
PubMedDate not supplied

Ultrastructural changes and immunocytochemical analysis of human placental trophoblast during short-term culture.

Trophoblastic cells, of at least 95 per cent purity by immunofluorescence and morphological criteria, were obtained from human term placenta by a simple trypsinisation method without the additional purification steps or complex culture conditions used by others. The differentiation of these cells was followed over four days in culture by fluorescence immunocytochemistry, by scanning and transmission electron microscopy and by light microscopy. The results support the idea that the isolated cells are cytotrophoblast and that these differentiate during this time into cells with characteristics of villous syncytiotrophoblast. This process involved first the formation of a multicellular layer of mononucleated cells, then the development of a syncytium of multinucleated cells and, not necessarily concurrently, functional differentiation. This may be a useful model for the study of syncytiotrophoblast function.

Antibodies, Monoclonal↗
PubMedDate not supplied

Two-sided culture of human placental trophoblast. Morphology, immunocytochemistry and permeability properties.

We describe the culture of human term placental trophoblast cells on cell-free amniotic membrane, with medium on both sides. Over the course of 2 days, the isolated cells, initially simple, mononucleated and probably cytotrophoblast, form a confluent layer of multinucleated syncytial cells with morphological and immunocytochemical properties of syncytiotrophoblast. This layer becomes polarized with respect to morphology, alkaline phosphatase distribution and hCG secretion. Contamination with amnion cells, and with other cell types that are present in placental tissue, was less than 1 per cent. A preliminary investigation of the permeability properties of the preparation showed that the trophoblast cell layer, rather than the amniotic membrane, was rate-limiting to transtrophoblast transfer, but that possible effects of the supporting membrane should be considered. The transtrophoblast transfer of D-glucose and the non-metabolisable analogue, 3-O-methyl-D-glucose (3OMG), had saturable and non-saturable/leak components in both directions, indicating that carrier-mediated processes were involved. The non-metabolisable amino acid 2-aminoisobutyrate (AIB) was both accumulated within the trophoblast cells, and transferred by saturable and non-saturable processes from the microvillous side, but no saturable accumulation or transfer was observed from the basal side, at the concentrations tried. The results suggest that this model may prove suitable for studies of transtrophoblast transfer.

3-O-Methylglucose↗
PubMedDate not supplied

Epithelial cell morphology and airspace size in hypoplastic human fetal lungs associated with oligohydramnios.

The relative frequency of different types of respiratory epithelial cells in normal fetal lungs (control, CON) and hypoplastic lungs associated with oligohydramnios (OH) was determined at the electron microscopic level and airspace size was measured. At 24+ weeks CON lungs had 82.4 +/- 1.2% undifferentiated cells, 15.9 +/- 1.2% type II cells, and 1.7 +/- 0.4% type I cells (n = 3), whereas OH lungs had 94.6 +/- 2.1% undifferentiated cells, 5.4 +/- 2.1% type II cells, and no type I cells (n = 3). At 36+ weeks CON lungs had 7.8 +/- 3.4% undifferentiated cells, 46.1 +/- 3.1% type II cells, and 46.1 +/- 1.4% type I cells (n = 3), whereas OH lungs had 37.7 +/- 1.2% undifferentiated cells, 42.5 +/- 1.7% type II cells, and 19.8 +/- 0.8% type I cells (n = 3). Differences between CON and OH lungs in the proportions of undifferentiated and type I cells at 36+ weeks were highly significant (p less than .001), whereas type II cell proportions did not differ significantly in either age group. The proportion of lung occupied by airspaces increased from 38.3% at 24+ weeks to 68.7% at 36+ weeks in CON lungs but only from 26.7% to 35.7% in OH lungs. The differences between the groups were significant at both 24+ weeks (p less than .01) and 36+ weeks (p less than .001). Mean airspace size in CON lungs varied from 2.8 x 10(-6) mm2 at 24+ weeks to 4.4 x 10(-6) mm2 at 36+ weeks and in OH lungs from 1.7 x 10(-6) mm2 at 24+ weeks to 2.7 x 10(-6) mm2 at 36+ weeks. These results give quantitative expression to the severity of impaired morphologic maturation in OH lungs.

Cell Differentiation↗
PubMedDate not supplied

Some scanning electron microscopic features of human cervical epithelium in cell culture.

Human cervical epithelial cells, growing out in confluent monolayers from small explants, develop cytoplasmic extensions from the margins of the growth, extending out and terminating on the glass substrate. The marginal fibrils are particularly frequent on the edges of cellular lamellipodia, protruding in advance of the growing edges. Marginal cells with microvilli tend to have more marginal fibrils on their leading edges than smooth more differentiated cells, and occasionally there is continuity between microvilli and marginal fibrils. Where there is cellular overlap, marginal fibrils extending over the surface of another cell can be seen; where these is an intercellular cleft, cytoplasmic bridges have the same appearance as marginal fibrils. Colchicine (10-6 M) did not affect marginal fibril formation.

Cells, Cultured↗