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Biomedical subjects

S J Challacombe

Publications and source records attributed to S J Challacombe.

At least 109 records · Page 6Linked to original sources
PubMed1990

Humoral immunity in root caries in an elderly population. 2.

Saliva specimens stored for 18 months at -20 degrees C with or without glycerol and the anti-protease benzamidine-HCl, lost all antibody activity for S. mutans. IgA activity in processed whole saliva decreased significantly after one week when stored either at 4 degrees C or -20 degrees C with or without glycerol, although it was stable in parotid saliva for at least 40 days. Loss of activity prior to processing was significant in the first 24 h, and the addition of 50% glycerol and storage at -70 degrees after processing, prevented loss of antibody activity in both whole and parotid saliva. Diurnal variations in IgA, lactoferrin and the IgA secretion rate were insignificant in parotid saliva but showed some fluctuations in whole saliva. Albumin and lactoferrin levels exhibited the greatest fluctuation in whole saliva specimens although IgA and IgA antibody levels were still more characteristic of the patient than the time of sampling. Monthly variations in IgA, IgA antibody activity and other parameters were least in parotid saliva and e.g., values for parameters that were high in patients samples on the first month, remained high during the 4-month study period. Statistical analyses showed a high correlation between values obtained for most of the 15 parameters that were measured in parotid and whole saliva specimens collected from greater than 20 patients during 2 successive visits. Whole saliva values for albumin, lactoferrin and albumin levels in parotid saliva, were most variable but differences were not significant. Hence, patients with very low or very high values, even in whole saliva, can be identified within the population on the basis of specimens collected at a single time.

Aged↗
PubMed1990

Association of selected bacteria with the lesions of root surface caries.

Plaque from the root surfaces of 165 subjects (mean age 65.5 years, 22-26 teeth/subject) was analysed for specific bacteria. Five subject groups were defined: A (DMFS 16.4), B (DMFS 55.9), C1 (DMFS 55.6), C2 (DMFS 57.0) and C3 (DMFS 48.1). Groups C1 and C2 had unrestored root surface lesions; Group A, B and C3 were free of unrestored root caries and differed in their coronal caries experience. Streptococcus mutans was isolated more frequently from the root lesions in Groups C1 and C2 than from intact root surfaces in Group A. Streptococcus oralis, Streptococcus mitis 1 and Streptococcus sanguis were isolated more frequently from Group A. The percentage contribution that S. mutans made to plaque from lesions in Groups C1 and C2 was higher than that from plaque in Group A and Actinomyces viscosus serovar 2 contributed more to plaque in Group C1 than in samples from Group A. The percentage counts of Lactobacillus in plaque from lesions in Groups C1 and C2 were higher than those from intact roots in Groups A, B, and C3. Subjects were also grouped on the presence of Lactobacillus and S. mutans in plaque samples. Samples with both organisms (n = 17) showed significantly higher isolation frequencies of specific strains of S. mitis 1 and also A. viscosus serovar 2 compared with samples of plaque containing S. mutans or Lactobacillus. Actinomyces naeslundii serovar 1 was not isolated from samples containing both S. mutans and Lactobacillus. The results confirm an association of S. mutans and Lactobacillus with root surface lesions and suggest a relationship between lesions and A. viscosus serovar 2.

Actinomyces↗
PubMed1990

A method for the identification of Streptococcus mutans in gingival margin plaque by immunofluorescence.

A method was developed to identify Streptococcus mutans in natural dental plaque by indirect immunofluorescence staining, using a high-titred polyclonal antiserum raised against a serotype c strain of S. mutans followed by an FITC conjugate. Specificity was determined by staining 45 representative strains of plaque organisms, which demonstrated minimal cross-reactions. In vitro incubation of S. mutans NCTC 10449 films with a human serum containing antibodies to S. mutans and the presence of extracellular polysaccharide did not inhibit staining. The staining method enabled 98% of the streptococci to be detected in mixtures of S. mutans NCTC 10449 and Lactobacillus casei NCTC 10302. S. mutans was detected at a ratio of 1:100,000 in mixtures of pure cultures. In plaque samples, S. mutans could be distinguished from other organisms, including an unidentified cross-reacting bacillus found in some gingival plaque samples. The results suggest that immunofluorescence is a fast, practical method for identifying specific bacteria in plaque and, therefore, could be of use in microbiological studies of caries.

Animals↗
PubMed1989

Preliminary characterization and distribution of vicia villosa binding cells in human tonsils.

The lectin Vicia villosa (VV) has been used for the separation of human and murine contrasuppressor T cells. These cells were characterized in cryostat sections of human palatine tonsils by double staining with VV lectin and monoclonal antibodies to macrophages, lymphocytes and their subsets using a fluorescein-rhodamine technique. VV lectin had an affinity for the CD8+ subset of lymphocytes and for a subset of macrophages within the germinal centre. The number and distribution of VV lectin binding cells was studied in paraffin sections of formalin fixed tonsils by the avidin-biotin-peroxidase technique. Positive cells in the germinal centres, mantle, interfollicular zones and fibrous connective tissue septa were quantified using an image analyser. These were found in greatest density in the interfollicular zone, correlating with the known distribution of T cells in human palatine tonsils. The binding of VV lectin to a subset of macrophages appears not to have previously been described nor have VV lectin binding CD8+ lymphocytes been demonstrated in sections of human tissues.

Antibodies, Monoclonal↗
PubMed1989

Ultrastructure and possible processes involved in the invasion of host epithelial cells by Candida albicans in vaginal candidosis.

Ultrastructural studies of Candida albicans in its invasive form obtained from lesions of patients with vaginal candidosis confirm that growth is intracellular. The invading hyphae show well defined organelles including a denticulate double-layered plasma membrane, nuclei, cristate mitochondria, endoplasmic reticulum and storage granules, especially when osmium tetroxide was used as the sole fixative for electron microscopy. The invasion of host epithelial cells is probably brought about by a combination of enzymatic, physical and mechanical processes.

Candida albicans↗
PubMed1988

Intracytoplasmic membrane configurations, vesicles and vesicular inclusions in Candida albicans.

Ultrastructural studies of Candida albicans in its invasive form obtained from oral lesions of patients with acute chronic candidosis, candidal infection on chorio-allantoic membrane of chick embryo, and of organisms grown artificially, have demonstrated the presence of an intracytoplasmic membrane system, vesicles and vesicular inclusions, in varying degrees. These variations appear to be attributed to the environment, cultural conditions and the age of the organism. Their origin, structure and distribution are described.

Animals↗
PubMed1987

A comparison of IgA in portal and peripheral venous blood.

A comparison of IgA in portal and peripheral venous blood was made to elucidate further any possible role of the liver in IgA functions in man. Over fifty paired samples of portal and peripheral blood were obtained from patients undergoing abdominal surgery. The samples were examined for total IgA and secretory IgA content, IgA immune complexes, and the proportion of polymeric IgA and IgA antibodies to Streptococcus mutans and Escherichia coli. No significant differences in the overall IgA concentration in portal and peripheral venous blood were found, but the concentration of secretory IgA was raised in portal blood (P less than 0.02). The IgA content of immune complexes (PEG precipitates) was significantly raised in portal sera compared with peripheral sera. Antibody levels to S. mutans or E. coli were not significantly different in the paired samples. A mean of 18.1% of the IgA in portal blood was greater than 7S in size compared with a mean of 15.3% in peripheral blood (P less than 0.01). Detectable differences between IgA in portal and peripheral venous blood could indicate some role of the liver in the transport of polymeric IgA and IgA complexes from serum to bile in man, but could represent increased production of these types of IgA in tissues drained by the portal vein.

Adolescent↗
PubMed1986

ELISA detection of human IgG subclass antibodies to Streptococcus mutans.

A sensitive enzyme-linked immunosorbent assay (ELISA) has been developed to measure IgG subclass antibodies against whole cells of Streptococcus mutans and to a purified streptococcal antigen (SA I/II). Bacterial cells were bound to the solid phase using methyl glyoxal and mouse monoclonal antisera against IgG and each IgG subclass were used to detect antibodies. Natural antibodies to S. mutans were predominantly of the IgG1 and IgG2 subclasses, though IgG3 and IgG4 antibodies were detectable in most subjects, and were the majority response in a few subjects. Antibodies to SA I/II were predominantly of the IgG1 subclass with virtually no activity detectable in the IgG3 and IgG4 subclasses. Inhibition studies suggested some restriction of IgG subclass responses to bacterial antigens since SA I/II and c polysaccharide could inhibit binding of all subclasses to whole cells of S. mutans equally, whereas glucosyltransferase, lipoteichoic acid and dextran showed greatest inhibition of the IgG3 and IgG4 subclasses.

Antibodies, Bacterial↗
PubMed1986

Haematological abnormalities in oral lichen planus, candidiasis, leukoplakia and non-specific stomatitis.

A series of 322 patients presenting with non-ulcerative conditions of the oral mucosa was examined for haematological abnormalities. The series was divided into 5 major groups--lichen planus (103 patients), candidiasis (50), leukoplakia (30), stomatitis or glossitis (66), and a miscellaneous group (73). The prevalence of anaemia, and deficiences in iron, folate and vitamin B12 in each group were compared with that found in 100 controls. The prevalence of anaemia in the series as a whole was not significantly increased, but the prevalences of sideropenia (14.0%), folate deficiency (4.7%) and vitamin B12 deficiency (3.1%) were increased as compared with controls. The prevalence of a haematological abnormality was increased in patients with lichen planus (18/103 p less than 0.05), stomatitis (15/66 p less than 0.01) and particularly in patients with Candidiasis (18/50 p less than 0.001). In the stomatitis group, approximately 45% of the male patients were found to have some haematological deficiency compared with less than 20% of the female patients. The increased prevalence of haematological deficiences suggests that patients presenting with non-ulcerative conditions of the oral mucosa (particularly candidiasis and non-specific stomatitis) should be screened haematologically and that, in some patients with candidiasis, haematological deficiencies may predispose towards candidal infection.

Adolescent↗
PubMed1985

The accessory cell function of murine Peyer's patches.

The cellular composition and certain functional characteristics of murine Peyer's patches (PP) were examined and compared with other lymphoid tissues. The composition of PP resembled most closely that of the spleen with the exception of a significant decrease in the number of adherent and phagocytic cells. Very few cells with dendritic morphology could be identified in Peyer's patches. Whole PP (and the nonadherent population) were capable of presenting antigen ovalbumin, human gammaglobulin, and purified protein derivative in a T proliferative assay to sensitized lymph node cells and to an antigen-specific T-cell clone. The antigen-presenting cell in both the spleen and PP was concentrated in the low-density population which floated on 1.080 bovine plasma albumin. However, equal numbers of whole and PP floaters were deficient in their capacity to present antigen compared with similar populations from spleen. Moreover, in PP the antigen-presenting cell appeared in the nonadherent rather than the adherent population as found with other lymphoid tissues. Similar results were obtained with (B6A)F1, CBA, A.TFR-1 and B10.S (12R) mice, suggesting that the inability of adherent cells from PP to present antigen effectively was not genetically determined. Whole and nonadherent PP contained cells capable of stimulating an allogeneic MLR, although again they were generally inferior to those of the spleen when comparable numbers of cells were employed. The adherent population of PP did not elicit an MLR. However, whole PP contained accessory cells needed for mitogen-induced proliferation since passage over nylon-wool columns resulted in a nonadherent fraction which did not respond to concanavalin A or phytohemagglutinin and the addition of adherent peritoneal exudate cells restored the lectin response. The differences noted in the accessory cell function in PP and other lymphoid tissues suggest the possibility that quantitative or qualitative differences in the function of these cells may explain some of the previously observed characteristics of PP, such as the inability to detect a primary antibody response in this tissue. The possibility that the development of gut-associated suppressor cells and their migration to peripheral tissues may be involved in the systemic tolerance that follows oral immunization and that these may be related to numerical and/or functional differences in macrophages or accessory cells is discussed.

Animals↗
PubMed1984

Natural antibodies in man to a protein antigen from the bacterium Streptococcus mutans related to dental caries experience.

Serum antibodies to a cell-wall protein antigen derived from Streptococcus mutans (SA I/II) were examined in 108 subjects by a solid-phase radioimmunoassay. As a control, antibodies to lipoteichoic acid and to Strep. mutans whole cells were examined and the relationship to dental caries of isotype-specific antibodies to both antigens determined. Serum-IgG antibodies to SA I/II and to Strep. mutans were significantly greater in subjects of low caries experience than in subjects of high caries experience, whereas serum-IgG antibodies to LTA showed no relationship. Serum-IgM antibodies to SA I/II were depressed in subjects with carious lesions, whereas IgM antibodies to Strep. mutans in the same subjects were raised. IgA antibodies against any antigen were not related to caries. Serum antibodies of each isotype to SA I/II were generally positively-correlated with antibodies to LTA but inhibition experiments demonstrated specificity of antibodies for each antigen. The relationship between antibodies to SA I/II and dental caries are consistent with those reported with antibodies to whole cells of Strep. mutans and suggest that high-serum IgG antibodies to SA I/II may be associated with protection against dental caries in man.

Adolescent↗
PubMed1984

Natural antibodies in man to Streptococcus mutans: specificity and quantification.

Antibodies to whole cells of Streptococcus mutans were examined in 108 subjects by a solid-phase radioimmunoassay and quantified by reference to isotype-specific affinity-purified antibodies. Serum antibodies of each isotype were present in all subjects examined. The mean concentration of serum antibodies to S. mutans was calculated as about 84 micrograms/ml of IgG (range 33-140 micrograms/ml), 26 micrograms/ml of IgA (range 12-43 micrograms/ml) and 9 micrograms/ml of IgM (range 4-15 micrograms/ml). The mean antibody values accounted for about 0.7, 1 and 0.8% of the total IgG, IgA, and IgM, respectively. Overall the antibody binding to whole cells of S. mutans accounted for about 0.8% of the total immunoglobulin. Inhibition experiments using a variety of purified cell wall antigens revealed that the binding of antibodies to whole cells could be inhibited by about 30% with a purified protein antigen (SA I/II) and with glucosyltransferase (GTF), by 25% with c polysaccharide and by 16% with lipoteichoic acid. The protein antigens GTF and SA I/II appear to be major immunogenic cell wall antigens, but natural antibodies in man that bind to S. mutans whole cells have been induced by several antigens, some of which are specific to S. mutans and some of which are shared with other Gram-positive bacteria.

Adolescent↗
PubMed1983

Oral tolerance and accessory-cell function of Peyer's patches.

Whole and nonadherent Peyer's patch cells were shown to present antigen to cloned antigen specific T-cells, albeit less efficiently than spleen cells. Unlike spleen cells, adherent PP cells did not present antigen, and PP lacked cells with classical dendritic morphology. The antigen presenting and MLR-stimulating cell in both spleen and PP were concentrated in the low density (BPA floaters) population. Soluble antigens (OVA, HGG, HSA, and KLH) are poorly presented by PP and do not elicit a T-cell proliferative response in PP when fed orally. These antigens induce oral tolerance and Ts cells in PP, MLN, and spleen. As with systemic tolerance, however, Ts (as measured by adoptive transfer) are not necessary for the induction of tolerance and can be eliminated by colchicine and Cytoxan without a significant effect on the initiation of tolerance. Evidence from studies in various inbred strains of mice suggests that oral tolerance is dependent on genetic factors, but the susceptibility of the strain is different from that induced by the systemic injection of the same antigen. Data are also presented that suggest that in studies of oral tolerance to various antigens, care must be exercised in excluding the effect of diet.

Animals↗
PubMed1983

Serum ferritin in recurrent oral ulceration.

A sensitive radio-assay for ferritin was developed and used to examine serum ferritin levels in 105 patients with recurrent oral ulceration (ROU), 41 patients with Behçet's syndrome (BS), 42 with other ulcerative oral lesions, 35 patients with non-ulcerative oral lesions and in 78 controls. Ferritin levels increased with age and were significantly higher in males than females. The mean ferritin concentrations in male patients with ROU, BS or with other oral ulcers were significantly reduced in comparison with controls, and in female patients were significantly reduced in those with major aphthous ulcers. The prevalence of low serum ferritin levels was about 8% in patients with ROU, 15% in BS and 9.5% in patients with other ulcerative oral lesions, compared with less than 3% in patients with non-ulcerative oral disorders and in controls. Most of the iron-deficient patients were female. Serum ferritin levels did not directly correlate with serum iron levels and may be a more accurate indicator of iron deficiency. Furthermore, serum ferritin can distinguish between patients with true iron deficiency and those with secondary sideropenia. It is suggested that in a small number of patients, oral ulceration may be a presenting sign of iron deficiency, and that in a further small proportion of patients, ROU already present will be exacerbated by concurrent iron deficiency. Both groups will show a therapeutic response to correction of the iron deficiency. The results suggest that serum ferritin levels are a useful part of the haematological investigations in patients with ROU.

Adult↗