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Biomedical subjects

S J Challacombe

Publications and source records attributed to S J Challacombe.

At least 73 records · Page 4Linked to original sources
PubMed1996

Serum antibodies to commensal oral and gut bacteria vary with age.

This study examined the relationship between serum antibody levels to selected bacteria from the commensal oral and gut flora with increased age in a healthy adult population. A total of 116 healthy subjects were studied consisting of the following age groups: 20-39 years (group A), 40-59 years (group B), 60-79 years (group C) and 80+ years (group D). Only significantly lower mean IgM antibody levels to Streptococcus mutans strain Guy's serotype c were observed in older age groups (P < 0.001). With Actinomyces viscosus NCTC 10951 significantly reduced IgM levels (P < 0.02) and significantly elevated IgA levels were observed with increased age (P < 0.05). IgA and IgG antibodies to Escherichia coli NCTC 10418 were increased significantly in the older age groups (P < 0.001), whilst a trend toward lower levels of IgM antibodies was recorded with age. No changes in IgA antibodies to Streptococcus faecalis NCTC 775 were observed but the lowest level of IgM antibodies were detected in the oldest age group (P < 0.05). Mean specific activity was decreased with age with IgM antibodies to the oral bacteria and increased with age with IgG and IgA antibodies to E. coli. Overall, our results suggest a general reduction in serum IgM antibody responses. This impairment in the circulatory IgM immune response may contribute to the increased occurrence of infections in the elderly.

Actinomyces viscosus↗
PubMed1996

The periodontal health of homosexual men with HIV infection: a controlled study.

OBJECTIVE: Identify types, prevalence and severity of periodontal changes associated with HIV infection. DESIGN: Cross-sectional controlled blinded study. SETTING: Open access genito-urinary medicine clinic. PARTICIPANTS: Convenience sample of 794 homosexual men aged 18-65. OUTCOME MEASURES: Prevalence, extent and severity of probing attachment loss (PAL), pocketing, gingival ulceration, gingivitis, bleeding on probing (BOP), gingival red bands and diffuse and punctate erythema of the attached gingiva (selected a priori). RESULTS: Prevalences in men with (n = 312) and without HIV (n = 260) were: PAL (> or = 1 site > or = 4mm), 59.6% and 28.5% respectively (P < 0.001, chi 2); pocketing (> or = 1 site > or = 4mm) 51.0% and 31.9% (P < 0.001); BOP, 96.5% and 92.3% (P = 0.038); gingival ulceration, 3.2% and 1.0% (P = 0.031), red banding, 12.2% and 10.0% (P = 0.410); diffuse erythema, 12.5% and 3.1% (P < 0.001) and punctate erythema, 9.6% and 1.1% (P < 0.001). Decreased CD4 lymphocyte counts predicted the presence, extent and severity of PAL (P = 0.023, 0.027 and 0.060) but not pocketing. Oral candidiasis predicted the extent and severity of gingivitis and the presence of diffuse and punctate erythema. (P = 0.037, 0.011, 0.002 and < 0.001). CONCLUSIONS: Destruction of periodontal attachment is associated with progression of HIV disease whereas pocketing is associated with HIV infection but not disease progression. Gingival ulceration is associated with HIV but gingivitis and erythema of the attached gingiva are most strongly associated with oral candidiasis. Gingival red bands were not associated with HIV infection.

Adolescent↗
PubMed1996

Aetiological factors for oral manifestations of HIV.

OBJECTIVES: Describe the oral diseases in HIV-infected individuals in London, UK and identify social and medical factors related to the presence of specific oral diseases. DESIGN: Dental clinics. SUBJECTS: Consecutive sample of 456 patients with HIV infection. METHODS: Social and medical history and clinical examinations. Univariate and logistic regression analysis. OUTCOMES: Presence of HIV-associated oral disease. RESULTS: 80% of patients with AIDS and 50% of patients with HIV had a specific oral disease. The most common diseases were hairy leukoplakia (30%), erythematous candidiasis (24%), pseudomembranous candidiasis (14%), angular chielitis (6%), necrotising periodontal disease (8%) and non-recurrent ulceration (6%). CONCLUSIONS: The presence of erythematous candidiasis was not related to advanced HIV disease. Pseudo-membranous candidiasis, hairy leukoplakia and mucosal ulceration were significantly associated with advanced HIV disease. Smoking was also identified as a strong aetiological factor in oral diseases. Longitudinal studies are required to further explore the prognostic significance of oral diseases in HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Does fluoridation harm immune function?

There have been suggestions, mainly in the lay press, that fluoridation might affect immunity. Careful examination of various studies on fluoride and immune function do not support this suggestion. Whilst fluoride at high concentrations can have inhibitory effects on lymphocyte and polymorphonuclear leucocyte function, these concentrations are many times higher than levels which would be expected from fluoridation. Fluoride can act as an immunological adjuvant. There is no evidence of any deleterious effect on specific immunity following fluoridation nor any confirmed reports of allergic reactions.

Adjuvants, Immunologic↗
PubMed1995

Candida albicans isolates from HIV-infected and AIDS patients exhibit enhanced adherence to epithelial cells.

The increased prevalence of oral candidosis associated with HIV infection must be intrinsically related to immunological changes in the host, but might also involve alterations to the infecting strains of yeast. This study aimed to determine if strains of Candida albicans isolated from asymptomatic HIV-infected individuals or AIDS patients possessed altered adherence properties in an in-vitro buccal epithelial cell (BEC) adherence assay. C. albicans isolates from 49 patients with HIV infection or AIDS adhered to BEC in significantly higher numbers than isolates from 49 control subjects (p < 0.001). No significant differences in adherence were detected between strains isolated from HIV-infected or AIDS subjects, or between strains isolated from C. Albicans carriers (low salivary C. albicans counts) or subjects with oral candidosis. The presence of whole saliva significantly inhibited the binding of candida to BEC (p < 0.001), but the significant difference in adherence between the HIV/AIDS and control isolates was maintained. The effect of saliva was independent of salivary candida antibodies and was abolished by treatment with protease or neuraminidase, suggesting the involvement of salivary mucins. The results of this study suggest that HIV infection is associated with the selection of strains of C. albicans with and increased ability to adhere to oral mucosa.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Age-related changes in immunoglobulin isotypes in whole and parotid saliva and serum in healthy individuals.

Mucosal infections account for the majority of infections seen in elderly people, but little is known of whether mucosal immunity decreases with age. The objective of this study was to investigate the effect of age on the levels of salivary and serum immunoglobulins and the salivary immunoglobulin secretion rates in a healthy adult population. Healthy subjects (116 total) were divided into the following age groups: 20-39; 40-59; 60-79 and >80 years. Unstimulated (resting) whole and stimulated parotid saliva and serum were collected from all participants. Salivary and serum immunoglobulins were quantified by enzyme-linked immunosorbent capture assays. The levels of serum immunoglobulin G (IgG) and IgM were significantly reduced in the oldest age group, whereas no significant reduction in the level of IgA with age was observed. The IgG and IgA levels in whole saliva increased significantly in the oldest age group D, but no changes were detected in IgM levels. No significant changes in any immunoglobulin levels with age were found in parotid saliva. However, significant reductions in the secretion rates of IgA and IgM, but not IgG, in whole saliva were detected in the oldest age group. No significant changes in the secretion rates in parotid saliva were found with age. Our results demonstrate a decline in immunoglobulin concentrations with increased age, which may contribute to the increased susceptibility of elderly individuals to infectious diseases.

Adult↗
PubMed1995

Detecting Legionella pneumophila in water systems: a comparison of various dental units.

The authors sampled 194 dental units over a 44-month period to detect the presence of Legionella pneumophila. They found L. pneumophila, usually in very low numbers, in 25 percent of the units over this time. However, higher counts were collected from 4 percent of the units, primarily from one model. The authors document colony counts collected from nine different models and those collected from air/water syringes vs. high-speed outlets, and they describe the effectiveness of disinfection.

Colony Count, Microbial↗
PubMed1995

Omeprazole and dry mouth.

BACKGROUND: Omeprazole causes irreversible inhibition of the hydrogen/potassium adenosine triphosphatase enzyme, leading to a marked reduction in both acid secretion and volume of gastric juice. Reported side-effects include nausea, vomiting, diarrhoea, constipation, and headache. We report the development of dry mouth during omeprazole therapy. METHODS: We have identified six patients taking omeprazole for more than 6 weeks who complained of a dry mouth. Salivary production was measured as whole salivary flow produced over a 10-min period spat into a collecting vessel and as 5% citric acid-stimulated parotid salivary flow collected with a Lashley cup device placed over the parotid duct. Flow rates were evaluated both during and after cessation of treatment. Saliva produced was then cultured for microbes. RESULTS: Four of the six had subnormal parotid or whole salivary flow rates on treatment that recovered after stopping treatment. The increase after treatment was marked in four. Significant amounts of Candida albicans grew from the saliva of the three patients with the lowest salivary flows; one saliva also grew Staphylococcus aureus. CONCLUSION: Salivary flow is reduced in some patients treated with omeprazole, returning to normal after cessation of treatment. This reduction may predispose to opportunistic infection, particularly in the edentulous.

Aged↗
PubMed1995

IgA subclasses in HIV disease: dichotomy between raised levels in serum and decreased secretion rates in saliva.

This study sought to determine IgA, IgA1 and IgA2 concentrations and secretion rates in unstimulated whole saliva and stimulated parotid saliva and IgA, IgA1 and IgA2 concentrations in serum from asymptomatic human immunodeficiency virus (HIV)-infected, acquired immune deficiency syndrome (AIDS) and control subjects. In whole and parotid saliva the mean IgA, IgA1 and IgA2 concentrations in the HIV and AIDS groups were lower than the control group (P < 0.05). Unstimulated whole and stimulated parotid saliva flow rates were lower in the HIV and AIDS groups compared with the control group, and reached statistical significance with respect to the mean parotid saliva flow rate in the AIDS group (P < 0.05). Mean IgA, IgA1 and IgA2 secretion rates in both the HIV and AIDS groups were significantly less than the controls (P < 0.05). In contrast, serum IgA, IgA1 and IgA2 concentrations were markedly raised in the HIV and AIDS groups compared with the control group (P < 0.001). There was no correlation between saliva and serum IgA concentrations within individuals. This study suggests that, in spite of the raised, polyclonally activated serum IgA concentrations associated with HIV infection, salivary IgA concentrations and secretion rates are reduced, emphasizing the dichotomy between systemic and secretory immunity.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Immunologic aspects of oral candidiasis.

Immunity to Candida infections in human beings is complex because of the different types of candidiasis, the different forms of Candida itself, and the interrelationships between the mucosal and systemic immune systems. Mucosal infection is by far the most common type of candidiasis, but systemic infection can also occur and the mechanisms for each may be quite different. In the oral cavity there are four main types of candidiasis, and hyphal and yeast forms of Candida may be present with both common and unique antigens. Humoral immunity is represented by salivary antibodies of the mucosal immune system and serum antibodies in the mucosa. Cell-mediated immunity may play a role particularly in chronic hyperplastic candidiasis. Salivary antibodies have been shown to inhibit adherence of Candida to buccal epithelial cells and to be protective in animal models. Serum antibodies against a 47kD antigen have been shown to correlate with protection and recovery from systemic candidiasis, but there is little evidence for a role of serum antibody in protection against infection of the oral cavity. In in vitro studies, both macrophages and polymorphonuclear leukocytes can kill yeast forms and inhibit hyphal forms of Candida and because chronic hyperplastic candidiasis is associated with intraepithelial polymorphonuclear leukocytes, these cells could be operative in vivo. Saliva contains a number of antifungal proteins including histatins and calprotectin that could act synergistically with specific factors. It is possible that cellular factors provide the main form of defense against mucocutaneous infection, whereas humoral factors play a larger role in the prevention of dissemination of Candida infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A scanning electronmicroscopy investigation of the structure of colonies of different morphologies produced by phenotypic switching of Candida albicans.

Variant colony formation by Candida albicans has been described and the phenomenon of phenotypic switching has been studied extensively. Whereas the microstructure of non-variant colonies has been investigated by scanning electronmicroscopy (SEM), the relationship between switched variant colonies and microstructure has not been described. The object of this study was to investigate and compared by SEM the microstructure of the normal colony type and five common variant colony types of C. albicans and to determine whether a pattern of dimorphic growth could account for the characteristic colony morphologies. A general relationship between colony type and structure was observed; smooth colonies consisted entirely of blastospores whereas regular, irregular-wrinkled and semi-rough colonies consisted of different proportion of true hyphae and blastospores. Regular extreme-jagged shaped colonies consisted of an almost pure culture of pseudohyphae, and colonies producing aerial hyphae were composed of pseudo- and true hyphae, as well as blastospores. These results show a clear relationship between colony morphology and development of particular cell types.

Candida albicans↗
PubMed1994

A comparison of salivary immunoglobulin A (IgA) and IgA subclass concentrations in predentate and dentate children and adults.

Local immune factors may play a role in the protection against oral disease and defences against microflora may be related to immunoglobulin A (IgA) subclass responses. The objectives of this study were to determine the concentrations and ratios of salivary IgA and IgA subclasses in predentate and dentate children and adults and to compare the levels in breastfed and bottle-fed infants. Whole saliva samples were collected from: a) 44 predentate children (mean age 4 months), b) 29 dentate children (1.5 years) and c) 28 adults (29.5 years). Immunoglobulin levels were assayed by enzyne-linked immunosorbent assay using colostral IgA standard. In the predentate children, the mean IgA, IgA1 and IgA2 levels were lower than in the dentate group but the difference reached statistical significance with IgA2 levels only. The comparative concentrations in the adult group were significantly higher than that in both children's groups. The IgA1:IgA2 ratio was similar in all 3 groups, at approximately 58:42. No significant differences were found in the concentration of salivary IgA and IgA subclasses in the breastfed infants compared with the bottle-fed ones. The results of this investigation confirm other studies suggesting that the concentration of salivary IgA subclasses are not significantly different between predentate and dentate children and that they do not reach adult levels until well after 2 years of age.

Adult↗
PubMed1994

Immunoglobulin A (IgA), IgA1, and IgA2 antibodies to Candida albicans in whole and parotid saliva in human immunodeficiency virus infection and AIDS.

Human immunodeficiency virus (HIV)-infected individuals are predisposed to recurrent oral candidiasis, and, although it has been assumed that this is because of deficient mucosal immune responses, this has not been properly established. The present study aimed to compare the concentrations and secretion rates of immunoglobulin A (IgA) and IgA subclass antibodies to Candida albicans in whole and parotid saliva samples from HIV-infected patients, AIDS patients, and control subjects. Levels of IgA antibody to Candida species in whole saliva were higher in the HIV group than in the controls and were highest in the AIDS group (P < 0.05). In parotid saliva, the mean antibody levels were significantly greater in HIV-positive patients than in controls (P < 0.05) but fell to lower levels in the AIDS group. The secretion rates of Candida antibodies in parotid saliva were reduced in AIDS patients compared with HIV patients. The specific activities of the IgA antibodies and both subclasses were significantly higher in the HIV and AIDS patients than in the controls in both whole and parotid saliva (P < 0.05). Antibody levels were significantly correlated with the numbers of Candida organisms isolated from saliva (P < 0.05). These results suggest clear differences in salivary antibody profiles among HIV-infected. AIDS, and control subjects and are indicative of a response to antigenic challenge by infecting Candida species. No obvious defect in the mucosal immune response in the HIV or AIDS groups that might account for the increased prevalence of candidiasis was apparent.

AIDS-Related Opportunistic Infections↗