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Biomedical subjects

P Badenoch-Jones

Publications and source records attributed to P Badenoch-Jones.

9 recordsLinked to original sources
PubMed1979

In-vitro modification of membrane receptors on cells of the mononuclear phagocyte system.

EA and EAC receptors have been studied on non-elicited and paraffin-induced macrophages, under a variety of culture conditions in vitro, for up to 7 days. A large decrease in the number of macrophages showing EAC receptors was found after treatment of the cells with BCG, but not "inert" particles such as latex and zymosan. This was reversible by 7 days. In the presence of a toxic material, Al(OH)3, both EA and EAC receptors were partially lost. The results obtained have been related to previous results obtained with cryostat sections of human leprosy skin lesions.

Animals↗
PubMed1979

Studies on the mechanism of macrophage aggregation induced by lymphokines.

Macrophage aggregation (measured by a light-scattering technique) induced by unpurified lymphokine preparations has been investigated. This has been shown to be Ca2+ or Mg2+ dependent and to be inhibited by a number of agents known to affect cellular physiology and biochemistry. The divalent cation ionophore A23187 causes a macrophage aggregation superficially similar to that induced by lymphokines, although differences were found. It is suggested that a biochemical response by the macrophage is required for aggregation induced by lymphokines, and thus measurements of macrophage aggregation allow a study of the early events in the response of macrophages to lymphokines.

Animals↗
PubMed1979

A sensitive technique for measuring specific macrophage aggregation: a comparison with macrophage migration inhibition, for the detection of lymphokine activity.

A new quantitative method for the measurement of macrophage aggregation, induced by lymphokine preparations, is described. This involves the continuous measurement of the light absorbance of stirred macrophage suspensions. The results have been compared with those obtained by measuring macrophage migration inhibition activity for the detection of lymphokine activity. Separation of crude lymphocyte culture supernatants by Sephadex G-200 shows that the material with aggregating activity is heterogeneous. The greater amount of this activity is not separated from macrophage migration inhibition activity, and has a molecular weight of 35,000--70,000. A comparison has been made with other published methods for measuring macrophage aggregation.

Cell Aggregation↗
PubMed1979

Complement activation by aluminium and zirconium compounds.

The activation of complement by a number of metal compounds, previously found to induce chronic inflammation, was investigated. Results obtained were compared with complement activation by inulin and zymosan. It was shown that complement activation by these metal compounds did not necessarily involve either the classical or the alternative pathways. Some of these compounds were unable to activate complement in the absence of detectable plasminogen. The results obtained indicate a relationship between the ability of these compounds to induce chronic inflammation in the guinea-pig and to activate complement.

Aluminum↗
PubMed1978

Ultrastructural observations on epithelioid cell granulomas induced by zirconium in the guinea-pig.

An ultrastructural study has been made of the allergic-type nodular granulomas that can be induced in guinea-pigs sensitised to sodium zirconium lactate. Lesions taken at the peak of granuloma development 7 days after skin testing contained epithelioid cells which could be recognised particularly by their content of rough endoplasmic reticulum, fimbriated cell membrane and typical nuclear appearance. Multinucleate giant cells were also seen. These cells were characterised by their large number of lysosome-like dense bodies and phagocytic structures. Both epithelioid cells and multinucleate giant cells were similar to those described in zirconium granulomas in man. However, these cells differed in a number of respects from similar cells observed in human sarcoidosis. A constant feature of the guinea-pig lesions was the presence of large numbers of apparently active fibroblasts.

Animals↗
PubMed1978

The effects of some aluminium and zirconium compounds on guinea-pig peritoneal macrophages and skin fibroblasts in culture.

The damaging effects of some industrially important Aluminium and Zirconium compounds on guinea-pig macrophages and skin fibroblasts have been investigated. Cell death was measured by the release of lactate dehydrogenase activity. The haemolytic properties of these compounds has also been investigated. There is a correlation between the ability of these compounds to form granulomas after intradermal injection in the guinea-pig, their toxic effects on macrophages and fibroblasts and their haemolytic properties. A possible mechanism of toxicity of these compounds towards macrophages and fibroblasts is suggested.

Aluminum↗
PubMed1976

The effects of added purines on urate and purine synthesis de novo by isolated chick liver, kidney and lymphoid cells.

1. Isolated chick lymphoid cells, together with isolated chick liver and kidney cells, incorporate [1-14C]glycine or [14C]formate into urate. 2. Of the cell types used, bursal cells incorporate 14C into urate at the fastest rate, although the output of total urate by bursal cells is only 10% that of liver cells. 3. When suspended in Eagle's medium the incorporation of 14C into urate is inhibited by adenine and guanine up to 1 mM. In contrast, the addition of 1 mM-AMP or -GMP results in a relatively large stimulation of this incorporation. 4. Added adenine is rapidly taken up by liver cells and then released in an unmetabolized form; AMP is taken up more slowly and is rapidly metabolized. The metabolites (possibly including adenine) are then released. 5. Intracellular liver 5-phosphoribosyl 1-pyrophosphate is approx. 0.7mM and remains constant or falls slightly during a 3 h incubation of the cells. 6. The addition of adenine or guanine, AMP or GMP, does not alter liver intracellular 5-phosphoribosyl 1-pyrophosphate concentrations. Added 5-phosphoribosyl 1-pyrophosphate is not taken up by liver cells. 7. The results are discussed in the context of the control of urate and purine synthesis de novo in the chick.

Adenine↗