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Biomedical subjects

J L Turk

Publications and source records attributed to J L Turk.

At least 19 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

Consequences of vasectomy: an immunological and histological study related to subsequent fertility.

Studies of 2 groups of patients 2 years and 8 years following vasectomy failed to demonstrate evidence of cell mediated immunity to sperm. Histological examination of testicular tissue from 11 patients undergoing reversal of vasectomy showed significant abnormalities in each. However, subsequent fertility within 15 months occurred in 7 (63.6%) of these patients. The nature of the testicular changes and the possible aetiological factors are discussed.

Adult↗
PubMed1979

Mitsuda-type lepromin reactions as a measure of host resistance in Mycobacterium lepraemurium infection.

The footpad reaction to autoclaved whole Mycobacterium lepraemurium organisms (MLM lepromin) in high-resistance (C57BL) and low-resistance (BALB/c) mice was studied. Infected C57BL mice gave a prolonged footpad response persisting for 4 weeks after skin testing with high and low doses of lepromin. This was accompanied by mononuclear cell infiltration. Uninfected C57BL mice gave no response. The majority of infected BALB/c mice gave no increase in footpad thickness. However, a high proportion of infected and control BALB/c mice tested with the high dose showed mononuclear cell infiltration which resembled that in C57BL mice. The low dose caused little infiltration in infected or control BALB/c mice. The course of infection in the two strains was different. Dissemination of organisms from the infected footpad was minimal in C57BL mice 5 months after infection. In BALB/c mice, dissemination to the draining lymph node and to some extent to the liver had occurred by 5 months. The draining lymph node of BALB/c mice showed histological evidence of local antibody formation, which uas not found in C57BL mice. On the basis of these findings, it was possible to fit murine leprosy in these two strains into a classification similar to that used for human leprosy.

Animals↗
PubMed1979

Sensitization of guinea pigs to levamisole.

Levamisole, an anti-helminthic drug used also as an immunostimulating agent, has been found to be a potent skin sensitizer in experimental animal models. Sensitization is associated with marked T-lymphocyte proliferation in the draining lymph node. It is suggested that immunostimulation through increase in the T-lymphocyte population could be a function of the strong sensitization induced by this compound.

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

Immunological unresponsiveness during induction of experimental autoimmune orchitis in guinea-pigs: studies in vivo and in vitro.

Groups of male and female guinea-pigs were immunized with homologous sperm derived from testis (TS) or epididyimis (ES) in Freund's complete adjuvant (FCA). In vivo investigations included skin tests at 2 weeks and development of aspermatogenesis (testis weight) at 4 weeks; in vitro assays were inhibition of migration of peritoneal exudate cells (PEC) and culture of blood leucocytes (lymphocyte transformation) at weekly intervals after immunization. Antigens used were heat-treated extracts of sperm used for immunization (BTS, BES); cells were also cultured simultaneously with PPD. Skin tests revealed anergy in males as compared with females: a larger quantity of antigen which caused partial unresponsiveness in females, caused profound unresponsiveness in males although the aspermatogenesis was less severe. In vitro tests also showed anergy during the active stages of the orchitis. This was non-specific for PEC (specific unresponsiveness was not excluded), but blood leucocytes showed only specific unresponsiveness (to BES). These and previous studies suggest that the unresponsiveness results from a desensitisation by sperm antigens released during the development of aspermatogenesis.

Animals↗
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↗
PubMed1978

Surface markers on lymphocytes and cells of the mononuclear phagocyte series in skin sections in leprosy.

E, EA and EAC rosetting techniques and Ig fluorescence were used in a study of receptor sites in cryostat sections of lesions through the spectrum of leprosy, and for comparison in some other mycobacterial and granulomatous lesions. Anti-C3, and trypsin were used as blocking agents. Lymphocytes in borderline lepromatous leprosy produced EA adherence and IgG fluorescence indicating B type cells. Lymphocytes in tuberculoid leprosy produced neither E or EA adherence and no fluorescence; these cells were presumed to be T cells. EAC and EA adherence was more marked in areas of macrophage infiltration, where there were few lymphocytes, than over the lympocytes themselves. Two distinct patterns emerged: (i) EA binding together with IgG fluorescence was seen in active lepromatous leprosy and could be localised to the surface of individual macrophages, and (ii) EAC binding together with IgM fluorescence was seen in the granuloma of tuberculoid leprosy and sarcoidosis, but could not be definitely related to cell surface; rather it was diffusely spread over the whole granuloma; EAC adherence was diminished by anti-C3 serum. Trypsin removed EA binding completely, but only diminished EAC adherence. It is suggested that the EA pattern indicates immunoglobulin receptors on macrophage and lymphocyte surfaces: and that the EAC binding (which is stronger than EA) involves C3 and IgM receptors at extracellular sites as well as C3 receptor sites on epithelioid cell surfaces. EA and EAC binding were enhanced in borderline tuberculoid leprosy in reaction and erythema nodosum leprosum, suggesting that immunoglobulin and complement receptor sites increase in number with enhanced hypersensitivity.

Cell Membrane↗
PubMed1978

Chronic malarial infection of mice: A comparison of single and multiple infections with Plasmodium berghei following P. yoelii.

Chronic malarial infection was induced in two groups of BALB/c mice by injection of Plasmodium yoelii followed by either one or repeated injections of P. berghei. Both groups showed a continuing but fluctuating splenomegaly, and a considerably increased reticulocyte count which also varied regularly, over a period of six months. During this time many mice had a very low grade parasitaemia demonstrable by subinoculation of blood into uninfected recipients. Mice infected with P. yoelii alone did not show any of these changes. One year after the first malarial attack all the infected mice had higher fluorescent antibody titres to P. yoelii than to P. berghei, titres against which were very low. Infected mice showed an increase in plasma cell proliferation in the red pulp of the spleen. There was a significant difference between mice which had received multiple injections of P. berghei and the other infected animals; the former had many germinal centres in the spleen, while the other infected groups did not.

Animals↗
PubMed1978

Delay in the development of the allergic response to metals following intratracheal instillation.

Intracheal intubation with the soluble metal salts potassium dichromate (K2Cr2O7) and nickel sulphate (NiSO4) causes a delay of up to 8 weeks in the development of delayed hypersensitivity to the specific agent. It is suggested that absorption of sensitizers by the respiratory route may, under certain circumstances, induce a state of specific immunological unresponsiveness, rather than necessarily lead to the development of a state of allergic sensitivity.

Animals↗