The sensitivity to apo-lactoferrin (apo-LF) of two oral isolates each of Candida albicans and C. krusei preincubated in either sucrose- or tunicamycin-supplemented media was investigated. Known apo-LF-sensitive isolates of both C. albicans and C. krusei demonstrated significantly increased resistance to apo-LF when preincubated in sucrose-supplemented media, but such preincubation had no effect on an apo-LF-resistant isolate of C. albicans, irrespective of the sugar concentration in the medium. Surprisingly, an apo-LF-resistant isolate of C. krusei demonstrated increased susceptibility to apo-LF when preincubated in sucrose. Further, when preincubated with tunicamycin, a chemical that interferes with candidal cell-wall formation, the susceptibility to apo-LF of the resistant isolates increased significantly. These results, when extrapolated in vivo, imply that dietary sucrose may diminish the anticandidal potency of salivary lactoferrin. However, the aberrant behaviour of a single isolate of C. krusei under these circumstances is possibly due to the different cell-wall structure of this yeast and needs to be further investigated.

Apoproteins↗

PubMed1995

Oral Candida albicans biotypes in Chinese patients with and without oral candidosis.

A total of 53 oral Candida albicans isolates from Chinese patients with clinically diagnosed oral candidosis (27 patients) or without overt signs and mycological manifestations of infection (26) were biotyped using two commercially available API micromethod kits and a boric acid-resistance test. There were no significant differences in the biotypes in health and disease, although the biotype A1R was present only in diseased individuals. The biotype A1S accounted for 21% of the total isolates, as in a number of other previous studies from the West. However, 14 of the 27 biotypes characterized were new biotypes that have not been described before. These preliminary data indicate that biotypic profile of C. albicans may bear no relation to the virulence of the isolates, and that diverse subtypes of the fungus are globally prevalent.

Boric Acids↗

PubMed1995

A novel method to study the hyphal phase of Candida albicans and to evaluate its hydrophobicity.

As little is known about the surface properties of the hyphal phase of the dimorphic fungus Candida albicans due to the difficulty in examining the latter phase in isolation, a novel method was designed to compartmentalize the two phases of the yeast using a commercially available filter-type device-Chemotaxicell. When yeast cells in the blastospore phase were incubated in filter chambers of Chemotaxicell submerged in hyphal-induction media, hyphae traversed through the pores of the filter into the exterior of the chamber enmeshing the entire outer filter surface, after 72 h of incubation. However, the inner or the chamber surface of the filter comprised mainly blastospores. The hydrophobicity of the two morphologic phases of the yeast was then compared using this method, by contact angle measurement. When the 72-h specimens with matted hyphal elements were evaluated, the contact angles varied depending on the incubation medium (such as TC 199 or serum), and in each case hydrophobicity of the hyphal phase was significantly higher than the blastopore phase yeasts. This simple, reproducible method should help not only in evaluating the properties of the hyphal elements of C. albicans but also in studying parameters such as saliva and serum, which are known to affect hyphal formation in vivo.

Analysis of Variance↗

PubMed1995

Attitudes and knowledge of Indian dental professionals about HIV infection and AIDS.

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Acquired Immunodeficiency Syndrome↗

PubMed1995

Biotypes of oral Candida albicans isolates in human immunodeficiency virus-infected patients from diverse geographic locations.

Oral Candida albicans isolates from HIV-infected individuals in Hong Kong, Australia, Germany and England were characterised using a biotyping system based on enzyme profiles, carbohydrate assimilation patterns and boric acid resistance of the yeasts. A total of 44 biotypes were found amongst the 117 oral C. albicans isolates examined. The major biotype A1R accounted for 17.9% of all isolates while the second commonest biotype was A1S (11.1% of isolates). Whereas these two biotypes were isolated from all the regions studied, there were a number of other biotypes unique to individual countries. The data indicate that there are many different sub-strains of oral C. albicans in HIV-infected patients, some of which are globally prevalent. However, further work is required to ascertain the diversity of oral C. albicans biotypes, if any, in health and disease.

AIDS-Related Opportunistic Infections↗

PubMed1995

Pseudomembranous oral candidiasis in HIV infection: ultrastructural findings.

A light and electron microscopic investigation of pseudomembranous candidiasis in HIV infection was undertaken as there is little data available on the ultrastructural features of the invasive phase of Candida in this disease. On examination of biopsy specimens of four patients, histopathology revealed the classic features of superficial candidiasis, including hyphal penetration down to the spinous cell layer, parakeratosis, acanthosis and spongiosis of the infected, superficial epithelium. However, in one case, hyphae traversed the entire epithelium and crossed the basal membrane, invading the adjacent connective tissue. Ultrastructural investigations revealed initial hyphal penetration through the intercellular spaces, possibly demonstrating thigmotropism. However, hyphal penetration was not solely confined to intercellular spaces, as some specimens demonstrated hyphal elements traversing both the cytoplasm and the nuclei of the spinous cells. In these areas of the epithelium appressoria-like appendages were often found at the hyphal tip. These phenomena, commonly described in plant fungi, have rarely been described in human material. Pools of desmosomes were seen in the vicinity of the hyphal pathways, implying that the penetration procedure is associated with detachment and congregation of desmosomes, possibly by enzymatic means. Interestingly, the host immune response to fungal invasion appeared to be minimal, as no immune-effector cells were seen closely associated with either the blastospores or the hyphae in any of the tissues examined. Whether the foregoing events are exaggerated by the abortive immune response seen in HIV-infected patients, or common in immunocompetent individuals during candidal invasion of epithelia, needs to be ascertained by further studies.

AIDS-Related Opportunistic Infections↗

PubMed1995

Association between carriage of oral yeasts and malnutrition among Tanzanian infants aged 6-24 months.

OBJECTIVE: To determine if there is an association between carriage of oral yeasts and malnutrition in infants. DESIGN: A case-control study within a cross-sectional study. The dependent variable was carriage of oral yeasts. The exposure variable was malnutrition and confounders to be adjusted for were age, sex, and breast-feeding. SETTING: A maternal and child health clinic in Dar-es-Salaam, Tanzania that offers routine medical check-ups to all expectant mothers and children aged between 0 and 5 years in its catchment areas. SUBJECTS AND METHODS: 972 infants aged 6-24 months participated. Smears from the tongue and cheek mucosa were examined for candidal hyphae and blastospores. Malnutrition was categorized according to Tanzanian standards (weight-for-age) and World Health Organization (WHO) standards (weight-for-height and height-for-age). MAIN OUTCOME MEASURE: Carriage of oral yeasts (hyphae and blastospores). RESULTS: Carriage of oral yeasts was significantly higher in the 227 malnourished compared with the 745 well nourished adjusted for confounders. Odds ratio for presence of hyphae in smears from the severely malnourished (weight-for-age) was 4.5 (90% CI: 2.0-10.0). Odds ratio for presence of hyphae was 2.3 (90% CI: 1.1-4.8) when weight-for-height were used to categorize for malnutrition. CONCLUSION: The study tends to confirm the generally held view that malnutrition may predispose to carriage of oral yeasts and subsequent oral candidiasis.

Candida↗

PubMed1995

Clinical, microbiological and ultrastructural features of angular cheilitis lesions in Southern Chinese.

OBJECTIVE: To obtain baseline data on angular cheilitis in Southern Chinese. DESIGN: A cross-sectional investigation of the clinical, microbiological and ultrastructural features of the condition. SUBJECTS AND METHOD: Thirty six Chinese adults with angular cheilitis; 28 controls matched for age and sex, with no inflammation. Clinical examination, swabs of lesions for microbiology, impressions of lesions for ultrastructure, using replica technique. MAIN OUTCOME MEASURES: Severity of lesions, associated signs and symptoms, incidence and type of microorganisms, ultrastructural features. RESULTS: Of a total 68 lesions 32 were bilateral and four unilateral. Forty four (65%) were mild (Type I) and the remaining 24 (35%) moderate (Type II). Infective agents were isolated from 37 (54%) lesions; pure growth of Candida spp and Staph. aureus was noted in nine lesions each; a mixed growth of the two in II, beta-haemolytic streptococci in three and a mixed flora including coliforms in the other five. Candida spp were present in one control, beta-haemolytic streptococci in two and coliforms in four others. Scanning electron microscopy revealed natural topography of the angular skin with sparse colonisation by bacteria and yeasts. CONCLUSIONS: Angular cheilitis in Southern Chinese seems to be characterised by a milder clinical presentation and classic infective agents of the disease: Candida spp and Staph. aureus.

Adult↗

PubMed1995

Newer saliva collection methods and saliva composition: a study of two Salivette kits.

UNLABELLED: Saliva is frequently used as a diagnostic fluid and several collection devices have been developed. OBJECTIVE: The aim of the present study was to investigate the validity and reliability of two types of Salivette collection kits (non-covered cotton roll and polypropylene covered polyether roll) relative to conventional collection of saliva using paraffin wax chewing stimulation. MATERIALS AND METHODS: Whole saliva samples were collected from 16 healthy volunteers. Following a cross-over design saliva was collected in a standardized way. The flow rate was determined and saliva samples were analyzed for pH, buffer capacity, electrolytes and protein/glycoprotein content. RESULTS: We find that Salivette methods do not allow evaluation of flow rate. pH was unaffected but buffer capacity was lower in Salivette collected than in paraffin wax-stimulated saliva. The non-covered cotton rolls reduced the content of Na+, K+, Cl-, as well as glycoprotein markers (hexosamines, fucose, sialic acid), lysozyme, lactoferrin, salivary- and myeloperoxidase but increased the concentrations of Ca2+, PO4(3)- and SCN-. Polypropylene covered polyether rolls affected saliva composition less than the non-covered cotton rolls. Thus, SCN- and sIgA concentrations were higher and lysozyme activity lower in the former (covered roll) saliva than in paraffin wax saliva. The reliability of the Salivette kits was good. CONCLUSION: We conclude that the Salivette method generates data significantly different from conventional paraffin wax-stimulated saliva such as buffer capacity and several electrolytes and organic components. Care should be taken in interpreting the results when such methods are employed.

Adult↗

PubMed1995

Oral disease in the elderly in long-term hospital care.

OBJECTIVE: To obtain baseline information on the prevalence of oral problems and disease in institutionalized elderly in a Scottish hospital. DESIGN: A cross-sectional clinical investigation with complementary microbiological studies as appropriate. SUBJECTS AND METHODS: A cohort of 147 elderly in five long-term care wards; collection of demographic data; clinical examination to determine: i) the dental and denture status and associated lesions such as Candida-associated denture stomatitis and angular cheilitis, ii) oral mucosal disease; swabs as appropriate for microbiology. MAIN OUTCOME MEASURES: Dental status, root caries prevalence; denture status and hygiene, and associated disease; oral mucosal health. RESULTS: Median period of institutionalization of 147 patients was 15 months and 65% were aged 80 years or more; the majority were significantly mentally impaired; 52% wore complete dentures, 9% were partially dentate, 19% possessed partial or incomplete dentures; 20% were neither dentate nor had dentures. Of 80 patients who verbalised their complaints, 35% complained of dry mouth and 45% had denture-related problems, principally discomfort. The commonest oral finding was a coated tongue (56%); angular cheilitis was present in 25%, and Candida-associated denture stomatitis in 19%; none had oral ulcers. CONCLUSIONS: There was considerable unmet dental need with significant oral disease and poor levels of oral and denture hygiene in this target group; both dental and medical professionals should act in concert to deliver curative as well as preventative dental care for the elderly living in institutions to improve their quality of life.

Aged↗

PubMed1995

The knowledge and attitude of Hong Kong secondary school teachers and students towards HIV infection and dentistry.

Although human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) are firmly entrenched in Hong Kong no data are available on the knowledge and attitudes of Hong Kong secondary school teachers and teenage children towards this infection, and their perception of infection control measures currently undertaken by the dental profession to prevent such infectious diseases. Hence a postal questionnaire survey of a total of 2,886 teenagers and 372 school teachers of 21 secondary schools in Hong Kong was conducted. The questionnaire comprised a total of 13 questions divided into two categories; the first, aimed at assessing the respondents' general knowledge and attitudes towards AIDS, and the second related to AIDS, dentistry and infection control. More than half of the students and one quarter of the teachers surmised that HIV infection is equivalent to developing AIDS. Although the great majority of the respondents (85-97 per cent) were aware that HIV can not be transmitted through sharing combs and meals, one in two teachers and one in three students thought that the virus could be transmitted through saliva. A large majority of respondents believed television to be the most, and dentists the least, informative source on AIDS out of a list of eight options. Approximately one half of both groups were concerned about contracting HIV infection during dental treatment and 65 per cent of students and 57 per cent of teachers thought that dentists did not have sufficient knowledge to identify AIDS patients. Finally, more than three quarters of the respondents thought that it would be ill-advised to visit a dentist treating HIV-infected patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗

PubMed1995

Relationship between the cell surface hydrophobicity and adherence of Candida krusei and Candida albicans to epithelial and denture acrylic surfaces.

C. krusei is an emerging pathogen, especially in immunocompromised hosts, and is implicated, together with Candida albicans, as an etiological agent of oral candidoses. As the cell surface hydrophobicity of these yeasts appears to be important in the pathogenesis of superficial candidoses, 20 oral isolates of C. krusei and 5 oral isolates of C. albicans were investigated using a biphasic (hydrocarbon/aqueous) separation hydrophobicity assay. All the C. krusei isolates demonstrated significantly greater hydrophobicity than the C. albicans isolates (p < 0.001). Further, there were significant intraspecies differences in cell surface hydrophobicity amongst C. krusei isolates. When hydrophobicity and adhesion to surfaces were compared using data from a previous study, there was a positive correlation between the cell surface hydrophobicity and adhesion of C. krusei isolates to HeLa surfaces (r = 0.53, p < 0.05), but not to acrylic surfaces. The current data, while confirming the inter- and intraspecies differences in cell surface hydrophobicity of Candida species, indicate that this attribute together with other cell surface features may determine the hierarchy of virulence amongst the different Candida species.

Candida↗

PubMed1995

Clinical predictors of HIV-1 infection among preschool children in Dar es Salaam, Tanzania.

Seroprevalence of HIV-1 infection was determined in children aged between eighteen months and five years, attending maternal and child health (MCH) clinics in Dar es Salaam, Tanzania. A total of 889 children were eligible for the study, however seven children could not be enrolled because their mothers/guardians absconded and blood could not be drawn from 21 children due to refusal of mothers/guardians and from another 12 children due to technical reasons. Therefore, the participation rate was 95.5%. Of the 849 children screened, 14 (1.65%) were found to have IgG anti HIV-1 antibodies in their sera. The main clinical features found in children with symptomatic HIV-1 disease were weight loss, generalized lymphadenopathy, recurrent fevers, and prolonged diarrhoea. The utility of clinical features suggestive of HIV-1 infection (according to CDC classification) in identifying HIV-1 infection in children was evaluated and found to have high sensitivity (100%), specificity (96.9%) and negative predictive value (100%), but a low positive predictive value (35%). Marked variations in progression to symptomatic phase were noted, whereby some relatively young children had progressed to symptomatic phase (CDC class P-2A), while some older children were still in the asymptomatic stage (CDC class P-1 C). None of the symptomatic HIV-1 infected children presented with neurological disease, severe opportunistic infections, or malignancies. Although reduced mid-upper arm circumference and weight-for-age were associated with HIV seropositivity, these clinical parameters had low positive predictive values compared to the CDC classification.

Child, Preschool↗

PubMed1994

'Inoculation injuries in the Lothian region'.

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Health Policy↗