PubMed Health⌕ Search

Biomedical subjects

N L King

Publications and source records attributed to N L King.

14 recordsLinked to original sources
PubMed1990

Collagen crosslinks and their relationship to the thermal properties of calf tendons.

The hydrothermal isometric tension and thermal transition temperature of collagen were determined in tendons from three different calf muscles. The levels of the nonreducible collagen crosslink, pyridinoline, and the collagen-associated Ehrlich chromogen were also measured in the three tendons. The reducible collagen crosslinks, hydroxylysinonorleucine, dihydroxylysinonorleucine, and histidinohydroxymerodesmosine were measured in two tendons. The thermal properties and levels of crosslinks were found to vary considerably between the different tendons, and also at different sites in two of the tendons. A strong correlation was observed between the thermal transition temperatures and the hydrothermal isometric tensions of the nine tendon sites examined. Both thermal properties correlated with the concentration of both pyridinoline and Ehrlich chromogen. The analogous behavior of the collagen-associated Ehrlich chromogen and the pyridinoline crosslink supports the role of the Ehrlich chromogen as a nonreducible crosslink.

Amino Acids↗
PubMed1982

Studies on the structure of connectin in muscle.

Enzymic hydrolysis, followed by amino acid analysis, provided no evidence for the presence of epsilon-(gamma-glutamyl) lysine or other isopeptide crosslinks in connectin. Gel elecrrophoresis in the presence of sodium dodecyl sulphate did not reveal any difference in connectin between normal and lathyritic muscle, indicating that lysyl oxidase does not initiate cross-link formation in connectin. Although connectin may be covalently crosslinked by some unknown mechanism, the available evidence suggests that the subunit of MW approximately to 900 000 is synthesised as a single polypeptide chain. In developing fetal muscle, myosin heavy chains are apparent some weeks earlier than connectin. This, together with the known susceptibility of connectin to hydrolysis, suggests that connectin exists in an exposed environment rather than as a core to the thick filament.

Amino Acids↗
PubMed1977

Deficiency of serum bactericidal activity against Salmonella typhimurium in sickle cell anaemia.

Systemic salmonellosis is a recognized complication of sickle cell anemia (SCA). In our initial study of SCA host defences against salmonella, we evaluated the bactericidal activity of serum against Salmonella typhimurium. When compared to controls, sera from eight out of nineteen SCA patients were deficient in bactericidal function. Levels of factor B, haemolytic complement and agglutinating antibody were similar in SCA and control sera. However, abnormalities that might theoretically account for the decreased antibacterial activity were observed in many SCA sera. These abnormal findings included: (a) defective function of the alternative complement pathway (decreased bacterial killing in the presence of Mg EGTA); (b) low serum C3 concentration; and (c) decreased total iron-binding capacity (TIBC), with a resultant increase in per cent saturation of iron-binding capacity. Of these deficiencies only the abnormal alternative pathway function was significantly associated with decreased serum bactericidal activity. A suggested function of serum bactericidal activity is prevention of bacteraemia by susceptible organisms. Thus diminished serum bactericidal capacity may increase the risk of Salmonella bacteraemia in some individuals with sickle cell disease.

Adolescent↗
PubMed1975

Activation of alveolar macrophages after lower respiratory tract infection.

Alveolar macrophage function has been studied in relation to bacterial infection of the lower respiratory tract. First, LRT macrophages were examined after exposure of rabbits to Listeria monocytogenes aerosols. Macrophages obtained from the LRT of animals 10 to 48 days after infection were activated, as evidenced by greater adherence to culture dishes and increased ability to ingest and kill both the original infecting organism and unrelated organisms, when compared to normal alveolar macrophages. Next, the in vitro effects on normal alveolar macrophages of incubation supernatants of control and antigen-stimulated lymphocytes (LRT and lymph node) from animals infected with L. monocytogenes or Streptococcus pneumoniae were evaluated. As manifested by increased adherence and phagocytosis, and an enhanced nonspecific bactericidal activity, alveolar macrophages were activated by the antigen-stimulated supernatants. These stimulated lymphocyte supernatants contain lymphokines (MIF), but the exact nature of the alveolar macrophage activating factor(s) remains to be determined. These observations, together with recent evidence that alveolar macrophages respond to lymphokines (MIF), suggest that the effector mechanism for cell-mediated immunity in the LRT is intact.

Aerosols↗