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Biomedical subjects

S Patterson

Publications and source records attributed to S Patterson.

At least 91 records · Page 5Linked to original sources
PubMed1982

Effect of iron saturation on transferrin uptake by reticulocytes. A morphological study.

The presence of iron on the transferrin molecule increases its affinity for and sojourn time on the reticulocyte. This could be due to selective internalization of iron-containing transferrin molecules. This possibility was investigated by electron microscopic autoradiography. Rabbit reticulocytes were incubated with rabbit transferrin at 6, 33, and 72% iron saturations, and the distribution of transferrin molecules at membrane and intracellular locations was assessed by grain counting. The results showed that (1) both apotransferrin and iron transferrin enter the cell interior and (2) the amount of intracellular transferrin was primarily controlled by the concentration of membrane-bound transferrin and not by its iron saturation.

Animals↗
PubMed1981

The interaction of influenza virus haemagglutinin with phospholipid vesicles - morphological and immunological studies.

HA-lipid spheres or "virosomes' were prepared using neutral or negatively charged, but not positively charged, phospholipids. Virosomes were similar in size and shape to native virus particles although the HA subunites were at least twofold less numerous on the virosomes. The HA subunites were attached by their narrow end to the lipid bilayer, and could be removed by digestion with bromelain. However, HA subunits released from intact virus by digestion with bromelain, which removed the hydrophobic tail of the molecule, could not attach to liposomes. Measurements of HA spikes before (mean length 14.2 +/- 0.9 nm) and after attachment to liposomes (mean length 13.3 +/-0.7 nm) and examination of freeze-fractured virosomes indicated that the HA did not penetrate deeply into the lipid bilayer. Similarly, HA subunits did not penetrate deeply into the lipid of virus particles. NP and M proteins could be attached to liposomes but could not be visualized by electron microscopy. Virosomes were taken up by Vero cells by viropexis with no evidence of fusion. Incorporation of HA or NP on to virosomes resulted in increased immunogenicity compared to free HA subunits or NP respectively. This adjuvant activity was not apparent in simple mixtures of HA liposomes. The antibody induced by HA subunits, virions and virosomes reacted similarly with strain-specific (SS) antigenic determinants of the haemagglutinin.

Animals↗
PubMed1981

The distribution of human coronavirus strain 229E on the surface of human diploid cells.

The distribution of human coronavirus strain 229E (HCV 229E) particles on the surface of human diploid (MRCc) cells was examined. Virus particles showed a totally random distribution on fixed cells and on cells to which virus had been adsorbed in the cold. A marked redistribution of virus particles was observed on warming virus-cell preparations to 33 degrees C for 20 min, the peripheral areas of the cell becoming relatively devoid of virus particles while the majority of particles were now located some distance from the edge of the cell. Redistribution did not occur in the presence of metabolic inhibitors.

Azides↗
PubMed1981

The effect of pneumatic tourniquets on skeletal muscle physiology.

The effect of 3- and 5-hour pneumatic tourniquets on skeletal muscle physiology was investigated. Maximum isometric tension development, contraction and half relaxation times were measured in the muscles lying immediately under and distal to the tourniquet. On release of the tourniquet no consistent difference between control and experimental muscles was observed with respect to contraction and half relaxation times; however, there was a marked reduction in maximum isometric tension development. On the sixth day after release of a 5-hour tourniquet, isometric tension was reduced to 2--20 per cent of the control value in the distal muscle and to 40--60 per cent of the control value in the compressed muscle. Six days after a 3-hour tourniquet the compressed muscle tension was reduced to approximately 80 per cent of the control value whilst in the distal muscle, tension development varied from normal to 64 per cent of the control value. Thus it is shown that the effect on muscle contraction after a 3-hour tourniquet is not immediately reversed by the restoration of the blood supply. A reduction in muscle strength follows which may take a week or more to recover.

Animals↗
PubMed1980

Infectivity of human coronavirus strain 229E.

The replication of human coronavirus strain 229E was observed by using indirect immunofluorescence in infected monolayers of MRC continuous cells. By 8 h after infection, bright cytoplasmic fluorescence was detected in cells infected with human coronavirus 229E. Discrete foci of infection were observed from 8 to 16 h after infection in cells infected with high dilutions of human coronavirus 229E; each fluorescent focus corresponded to a single virus infection. A fluorescent focus assay is described, using indirect immunofluorescence, which is more sensitive than the established techniques of tube titration and plaque assay. Particle/infectivity ratios for unpurified and purified virus preparations revealed a considerable drop in infectivity on purification.

Cell Line↗
PubMed1979

Studies on the mechanism of influenza virus entry into cells.

Inhibitors of glycolysis, oxidative phosphorylation, protein synthesis, membrane Na&-K& transport and microfilament and microtubule function have been employed to elucidate the mechanism of influenza virus uptake by CAM and CEF cells. Electron microscopy demonstrated uptake of virus by viropexis in the presence of all these inhibitors. Utilizing a pulse labelling technique, virus entering CEF cells in the presence of inhibitors was shown to initiate specific virus polypeptide synthesis after neutralization of remaining extracellular virus and removal of the inhibitors. As a consequence of these findings an energy independent mechanism of viropexis has been proposed.

Animals↗
PubMed1979

The effect of pneumatic tourniquets on the ultrastructure of skeletal muscle.

Experiments have been carried out on rhesus monkeys to determine the effect of the application of a pneumatic tourniquet on the ultrastructure of the muscles of the lower limb. Tourniquets were applied for periods lasting between one and five hours. The changes in the muscle lying immediately under the cuff of the tourniquet were more marked than those observed in muscle distal to the cuff. Three hours appears to be close to the limit of the time that a muscle can resist the sustained compression of a tourniquet.

Animals↗
PubMed1976

Electron microscope observations on the entry of avian infectious bronchitis virus into susceptible cells.

Infectious bronchitis virus was observed to enter cells of chicken chorioallantoic membrane by viropexis. There was no support for the suggestion that entry took place by fusion of viral and plasma membranes. The results of electron microscopy showed that virus attachment occurred both at 4 degrees and at 37 degrees C. Viropexis was not observed until the preparations were warmed. Similar results were obtained using chicken kidney cells. Quantitative data obtained from a plaque counting system employing chicken kidney cells indicated that attachment was the same at both temperatures and that some virus particles were taken up at 4 degrees C. Virus uptake was triggered by attachment of the virus to the cell membrane and the subsequent process of virus entry visualised by E. M. appeared to proceed without the involvement of lysosomal enzymes. No intracellular virus was located by electron microscopy in warmed preparations when virus was treated with specific antiserum, either before or after adsorption to the cells.

Adsorption↗
PubMed1976

Mechanism of myofibril growth and proliferation in fish muscle.

The mechanisms of myofibril growth proliferation were investigated in the red and white muscles of fish. In both types of muscle the ratio of lattice filament spacings between the Z disk and M line was found to be greater than that required for perfect transformation of a square into a hexagonal lattice. This mismatch was considered to result in the thin filaments being pulled obliquely instead of at right angles to the Z disk. The angle of pull of the thin filaments was measured in longitudinal sections. The splitting process was found to decrease the degree of pull. Splitting was also observed in transverse sections of the peripheral myofibrils. In both red and white fibres these myofibrils were found to commence splitting when they reached a size of approximately 1-2 mum diameter. Evidence from ultrastructural and autoradiographical studies suggested that growth of the myofibrils within the fibres is centrifugal. The outermost myofibrils appear to be the ones which are being built up and which split. The data indicated that in fish muscle a considerable number of filaments may be added to the daughter regions whilst splitting of the myofibril is still continuing.

Animals↗