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Biomedical subjects

S Patterson

Publications and source records attributed to S Patterson.

At least 73 records · Page 4Linked to original sources
PubMed1985

Relationship between large granular lymphocytes and NK-1.2+ cells from normal and poly(inosinic:cytidylic acid) (poly(I:C]-treated mice.

The present work analyzes the relationship between large granular lymphocytes (LGL), NK-1.2+ cells, and natural killer (NK) activity of C3H/HeN mice. Different hematic cell fractions were obtained according to their nylon-wool adherence and density on Percoll gradients. NK-1.2+ cells (8% of nucleated cells) were more numerous than LGL (3% of nucleated cells) in the input blood population. Eighty-five percent of LGL were recovered from the sorted NK-1.2+ cell fraction. After incubation on nylon-wool column, 63% of LGL and 36% of NK-1.2+ were eluted in the nonadherent fraction. Eighteen percent of NK-1.2+ cells were recovered from the most adherent elutable cell fraction. After the discontinuous Percoll gradient most LGL were present in the low-density fractions while 20% of NK-1.2+ cells were recovered from the highest-density fraction. NK activity was significant both in the nylon-wool-nonadherent and -adherent fractions. After the Percoll gradient most NK activity was present in the low-density fractions. In the present experimental conditions treatment poly(inosinic:cytidylic acid) (poly(I:C] did not increase the numbers of LGL and NK-1.2+ cells either in the blood or in the spleen. However it increased significantly the NK activity of the input cell populations and of the nonadherent and low-density fractions. Similarly, exposure of specific pathogen-free (SPF) mice to non-SPF conditions stimulated NK cytotoxicity but did not alter the percentage of LGL in the blood or in the spleen. Poly(I:C) treatment induced a shift of LGL and NK-1.2+ cells toward the low-density fractions. In poly(I:C)-treated mice images of granule secretion from LGL were detected. Taken together, the present results indicate that LGL and NK-1.2+ cell populations do not totally overlap. Moreover subpopulations of LGL and NK-1.2+ cells can differ in NK activity, morphology, density, adherence to nylon wool, and response to poly(I:C).

Animals↗
PubMed1985

Infection of cultured human muscle cells by influenza virus.

In a search for myotropic viruses with a potential to initiate muscle autoimmunity, we found that two strains of influenza A virus, A/England/863/78 (H3N2) and the reassortant virus X-47 (H3N2), could infect human syncytial myotubes lytically. The X-47 strain could, in addition, infect unicellular precursor myoblasts. Intracellular viral protein synthesis was demonstrated by pulse-labelling studies in both cell types with both virus strains. By immunofluorescence and immunoelectron microscopy, viral antigens were demonstrated in infected muscle cells specifically identified by double staining with monoclonal antibodies to either of two independent muscle-specific antigens. However, using 'co-capping' techniques in conjunction with electron microscopy, there was no evidence of association between viral haemagglutinin and the acetylcholine receptor (one major target of autoimmunity to muscle cells) on the infected cell membrane.

Antigens, Viral↗
PubMed1985

Biology of cloned cytotoxic T lymphocytes specific for lymphocytic choriomeningitis virus: clearance of virus and in vitro properties.

We have generated lymphocytic choriomeningitis virus-specific, H-2-restricted cytotoxic thymus-derived lymphocyte (CTL) clones. By using these reagents in several in vitro assays with infected target cells, we show that CTLs by themselves prevent the release of infectious virus into culture fluids and significantly lower the titers of infectious virus previously produced. This ability of cloned CTLs is not influenced by monensin. However, monensin does abrogate the ability of CTLs from spleens of mice primed 6 to 8 days previously with virus to kill virus-infected syngeneic targets. When tested for the participation of lymphokines in this system, the CTLs proliferate when reacted with syngeneic lymphocytic choriomeningitis virus-infected macrophages but fail to make interleukin-2. These CTLs make gamma interferon when reacted with syngeneic virus-infected targets. However, the production of interferon does not directly correlate with CTL-mediated killing. The number of H-2K and D molecules expressed on the target cell surface is not altered during the course of lymphocytic choriomeningitis virus infection. Electron microscopy shows finger-like projections of the CTL clone thrust into the infected cell and lesions bearing an internal diameter of approximately 15 nm in those membranes, illustrating the lytic process.

Animals↗
PubMed1985

The structure and biosynthesis of epidermal growth factor precursor.

The structure of mouse submaxillary gland epidermal growth factor (EGF) precursor has been deduced from complementary DNAs. The mRNA is approximately 4800 bases and predicts prepro EGF to be a protein of 1217 amino acid residues (133 X 10 Mr). EGF (53 amino acid residues) is flanked by polypeptides of 188 and 976 residues at its carboxy and amino termini, respectively. The amino terminus of the precursor contains seven cysteine-rich peptides that resemble EGF. Towards the carboxy terminus is a 20-residue hydrophobic membrane spanning domain. The mild portion of the EGF precursor shares a 33% homology with the low density lipoprotein receptor, which extends over 400 amino acid residues. These features suggest that EGF precursor could function as a membrane-bound receptor. RNA dot-blot analysis and in situ hybridization show EGF mRNA to be abundant in the submaxillary gland, kidney and incisor tooth buds. Lower EGF mRNA levels were found in the lactating breast, pancreas, small intestine, ovary, spleen, lung, pituitary and liver. In the kidney EGF mRNA was most abundant in the distal convoluted tubules. Analysis of EGF precursor biosynthesis in organ culture of the submaxillary gland and kidney showed differential processing of the precursor in the two tissues. In the submaxillary gland immunoreactive low molecular weight EGF was produced, but in the kidney the high molecular weight precursor was not processed. In the distal convoluted tubule of the kidney EGF precursor may act as a receptor that is involved in ion transport.

Amino Acids↗
PubMed1984

The plasma protease inhibitor system (Pi) of Standardbred horses.

The plasma protease inhibitor system (Pi) of Standardbred horses was studied by thin-layer, high-voltage, acid polyacrylamide gel electrophoresis (pH 4.6) followed by protein staining and staining for trypsin and chymotrypsin inhibition. In addition to the eight Thoroughbred alleles (PiF, G, I, L, N, S1, S2, U), another 10 alleles, designated PiH, J, K, O, P, Q, R, V, X, Z, were postulated to account for the 98 Pi types which were observed in Standardbreds. Detailed inhibitory spectra of the 'new' alleles were determined and further exceptions to the Pi1, Pi2 classification of Juneja et al. (1979) were found. Limited family data demonstrated the genetic nature of the 'new' variants and confirmed the allelic inheritance of the 'new' Pi variants.

Alleles↗
PubMed1983

Ultrastructural and immunofluorescence studies of early events in adenovirus-HeLa cell interactions.

Scanning electron microscopy and immunofluorescence techniques show that the attachment of adenovirus type 5 to HeLa cells is followed by a temperature-dependent redistribution of virus particles on the cell surface. Metabolic inhibitors and cytochalasin B, a drug that impairs microfilament function, blocked this redistribution. Transmission electron microscopy studies demonstrated that inhibition of redistribution was paralleled by an inhibition of virus internalization. In further experiments virus and cells were incubated at 4 degrees C and then treated with adenovirus 'soluble' antigens to block unoccupied virus receptors. On warming these preparations to 37 degrees C, the internalization of attached virions was found to be impaired. It is proposed that energy-dependent redistribution of attached adenovirus particles on the cell surface facilitates entry by bringing virions into contact with sufficient receptors to allow internalization.

Adenoviruses, Human↗
PubMed1982

Thiourea prevents cytotoxicity and mutagenicity, but not sister-chromated exchanges in V79 cells treated with cis-diaminedichloroplatinum (II).

This work shows that cis-diaminedichloroplatinum(II)'s (cis-DDP) mutagenicity, as well as its cytotoxicity, can be prevented by subsequent treatment with thiourea. Sister-chromatid exchanges (SCE) induced by cis-DDP are only partially prevented by thiourea under conditions where mutagenicity is totally inhibited. A 4.5-h delay in the addition of thiourea following cis-DDP treatment results in an almost complete loss of its ability to prevent mutagenicity, but only a partial loss of its ability to prevent cytotoxicity and sister-chromatid exchanges.

Animals↗
PubMed1982

Evidence of diffusion artefacts in diaminobenzidine immunocytochemistry revealed during immune electron microscope studies of the early interactions between influenza virus and cells.

Anti-haemagglutinin-labelled antibodies have been used to search for influenza entry into cells by fusion of viral and plasma membranes. The plasma membranes of infected cells were stained by immunoperoxidase but not by immunoferritin reagents. It is suggested that the staining obtained with the peroxidase conjugate was due to diffusion of the diaminobenzidine reaction product away from the enzymic site. Immunoferritin labelling provided no evidence for entry of influenza by fusion of viral and plasma membranes under conditions of physiological pH.

3,3'-Diaminobenzidine↗
PubMed1982

Replication of human respiratory coronavirus strain 229E in human macrophages.

Evidence for the replication of human coronavirus strain 229E (HCV 229E) in macrophages is presented. Virus antigen was detected in macrophages by an immunofluorescent technique 24 h after infection and virus particles were observed in the cisternae of the endoplasmic reticulum by electron microscopy. Giant cells were observed by light and scanning electron microscopy, and large multinucleate cells were seen by thin-section electron microscopy, suggesting that HCV 229E can induce syncytial formation in cultured human macrophages. Furthermore, the production of infectious virus by macrophages was demonstrated by an infectious centre assay.

Antigens, Viral↗
PubMed1982

Polymorphism of the NS1 proteins of type A influenza virus.

The type-specific non-structural protein 1 (NS1) of influenza A viruses was found to be heterogeneous with respect to charge, varying in pI by more than two orders of magnitude, and to phosphorylation. Phosphorylation was strain-specific, variable in extent between strains, and in some strains NS1 proteins were not detectably phosphorylated. Phosphorylation was not responsible for the major variations in charge as, paradoxically, the most acidic NS1 proteins were not phosphorylated. Cytoplasmic inclusions, which are formed between NS1 proteins and cellular RNA in infections with a number of human strains, were absent from A/FP/Rostock-infected cells and do not, therefore, appear to be essential in virus multiplication. We suggest that the acidic nature of the NS1 of A/FP/Rostock may prevent it from binding RNA and hence from forming inclusions. The variation in charge of NS1 proteins which we determined experimentally correlates with the overall differences in charge adduced from published amino acid sequence and implications of this variability to the biological role of NS1 are discussed.

Animals↗
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↗