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A F Rowley

Publications and source records attributed to A F Rowley.

50 records · Page 3Linked to original sources
PubMed1986

Preliminary studies on the chemotactic potential of dogfish (Scyliorhinus canicula) leucocytes using the bipolar shape formation assay.

The bipolar shape formation assay, previously used to determine the chemotactic potential of various factors for mammalian leucocytes, was tested in the present study with granulocytes of the lesser spotted dogfish, Scyliorhinus canicula. Bipolar shape formation was found to be a temperature dependent process with maximal formation observed at 30 degrees C. Addition of the formyl peptide, N-formyl-methionyl-phenylalanine failed to induce any bipolar forms at all temperatures and concentrations tested.

Animals↗
PubMed1986

Leukotriene B4 induces enhanced migration of fish leucocytes in vitro.

Leukotriene B4 (LTB4) was found to induce enhanced migration of the eosinophilic G1 granulocyte of the dogfish Scyliorhinus canicula in the migration under agarose assay. Higher levels of LTB4, however, were required to produce this effect than with mammalian neutrophils under similar conditions. It is postulated that this may be due to the dogfish granulocytes possessing fewer receptors for LTB4 than their mammalian counterparts. The eosinophilic G3 granulocyte was also tested using the same assay but results were inconclusive. The effect of LTB4 on dogfish G1 and G3 granulocytes was also monitored with the bipolar shape formation (BSF) assay. LTB4 induced BSF in both granulocyte types, and this method appeared to be more sensitive than the migration under agarose assay. Whether the enhanced migration observed is a result of chemotaxis or chemokinesis is not determined. This present study represents the first known report of the function of LTB4 in a non-mammalian vertebrate.

Animals↗
PubMed1985

Separation of leucocytes in the dogfish (Scyliorhinus canicula) using density gradient centrifugation and differential adhesion to glass coverslips.

The blood of the dogfish, S. canicula, contains several types of leucocytes, namely thrombocytes, monocytes, lymphocytes and four populations of granulocytes. Three of these granulocyte types, G1, G3 and G4, are eosinophilic while G2 is heterophilic/neutrophilic. All of the leucocyte types, with the exception of G2 granulocytes and monocytes, can be separated by means of their differential adherent properties to glass and by density gradient centrifugation. Thrombocytes, G3 and G4 granulocytes can be separated in good purity by single-step methods while G1 granulocytes and lymphocytes require a combination of density gradient centrifugation followed by adherence to glass to remove contaminating thrombocytes. Depending on the cell type, between 11-45% of cells with consistently high viability can be recovered after separation. Separated populations of the thrombocytes and granulocytes will be especially useful for studies on the role of such cell types in inflammation.

Animals↗
PubMed1985

The effect of anticoagulants on Blennius pholis L. Leucocytes.

The effects of ethylenediamine-tetraacetic acid (EDTA), heparin and tri-sodium citrate (TSC) on various haematological parameters in the blenny, Blennius pholis, were investigated. EDTA and heparin, at the concentrations tested, proved adequate in preventing coagulation although leucocyte viability was reduced when the higher levels were used. TSC failed to prevent coagulation at all concentrations tested. Short (5 min) and long (20 min) term contact of these anticoagulants with blood did not produce any significant changes in leucocyte proportions. Heparin is regarded as the most suitable anticoagulant for use with B. pholis blood.

Animals↗
PubMed1982

Ultrastructural and cytochemical studies on the blood cells of the sea squirt, Ciona intestinalis. I. Stem cells and amoebocytes.

The ultrastructure and cytochemistry of the stem cell and amoebocytic blood cells of the sea squirt, Ciona intestinalis, are described. The stem cells are characterised by a high nuclear: cytoplasmic ratio and on undifferentiated cytoplasm. In thin sections, four types of amoebocytes can be demonstrated: non-vacuolar and vacuolar hyaline amoebocytes, granular amoebocytes, and refractile amoebocytes. The cytoplasm of non-vacuolar amoebocytes contains many vesicles, which although structurally similar to primary lysosomes are in most cases acid phosphatase-negative. The granular amoebocytes enclose several microtubule-containing granules and vacuoles with electron-dense vanadium deposits, while the refractive amoebocytes are characterised by their pleomorphic inclusions and spike-like pseudopodia. Both the granules and inclusions of these amoebocyte types are peroxidase- and acid phosphatase-negative indicating that they are probably not lysosomes. The possible interrelationships of the four amoebocyte types are discussed, and it is suggested that the vacuolar hyaline amoebocytes may differentiate into granular amoebocytes.

Acid Phosphatase↗
PubMed1980

Insect erythrocyte agglutinins. In vitro opsonization experiments with Clitumnus extradentatus and Periplaneta americana haemocytes.

The effect of naturally occurring haemagglutinins on the in vitro phagocytosis of sheep erythrocytes by the blood cells (haemocytes) of Clitumnus extradentatus and Periplaneta americana was studied. The results showed that the haemagglutinins in both species failed to act as opsonins. Indeed, in some instances, incubation of erythrocytes in haemolymph resulted in less avid ingestion as compared with the saline-incubated controls. This reduced phagocytosis was probably caused by the clumping of erythrocytes on the haemocyte monolayers, leaving fewer single red cells available for uptake. The possible roles of these erythrocyte agglutinins in the host defence systems of insects are discussed.

Animals↗
PubMed1979

An ultrastructural and cytochemical study of the interaction between latex particles and the haemocytes of the wax moth Galleria mellonella in vitro.

The plasmatocytes are the major phagocytic blood-cell type in the haemolymph of the wax-moth, Galleria mellonella. In the present study, these cells were allowed to attach to tissue culture dishes for 1 h, rinsed and then incubated with latex beads for up to 72 h. These cells were then fixed for routine transmission electron microscopy and acid phosphatase cytochemistry. Intracellular latex particles were found in tight, ill-defined phagosomes, which were often clearly associated with the Golgi complexes of the plasmatocytes. Fusion of both primary lysosomes and multivesicular bodies with the phagosomes occasionally occurred and this resulted in the accumulation of an acid phosphatase positive reaction product around the test particles. Subsequent experiments showed that this acid phosphatase activity was mainly associated with the primary lysosomes. The results of the lysosome/latex interactions are compared with those obtained from similar studies on the digestive mechanisms in other phagocytes.

Acid Phosphatase↗
PubMed1977

The role of the haemocytes of Clitumnus extradentatus in haemolymph coagulation.

Light and electron-microscopic observations of the blood cells (haemocytes) of the stick insect Clitummus extradentatus in vitro showed that two morphologically distinct cell types, the cystocytes and granular cells are involved in haemolymph coagulation. Both these cell types contain a variable number of electron-dense granules which upon release cause progressive coagulation and precipitation of the haemolymph. In the cystocytes this release is extremely rapid (30-60s) while in the granular cells it only occurs after 1-2 min in vitro. The role of these cells in haemostasis is discussed together with the possible significance of the involvement of two cell types in the coagulation process.

Animals↗
PubMed1976

The granular cells of Galleria mellonella during clotting and phagocytic reactions in vitro.

Light and electron-microscopic observations of the blood-cells (hemocytes) of the wax-moth Galleria mellonella showed that hemolymph coagulation was initiated by the rapid release of material from the granular cells. During incubation for short terms in vitro these cells showed progressive degranulation as material derived from the granules was discharged into the hemolymph. Attempts to determine the nature of this material by staining with ruthenium red proved mainly unsuccessful. When challenged with bacteria in vitro the granular cells failed to phagocytose these particles and instead the bacteria became embedded in the granular material surrounding these cells. The mode of coagulation reported here is compared with previous reports of the role of invertebrate hemocytes in hemolymph clotting.

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