Scanning Electron Microscopy of Black Stain on Human Permanent Teeth

Black stain may develop on the coronal surfaces of human teeth, and this type of stain is common in the Hong Kong Chinese population. The present study was undertaken to ascertain if the deposit conforms in composition to the black stain found elsewhere, and to describe its ultrastructure using the scanning electron microscope. Gram-stained smears were made from black stain on the teeth of 11 adult Hong Kong Chinese and studied microscopically. From another 15 persons extracted teeth exhibiting black stain were obtained and fixed. Two ground sections were made from each tooth, one was stained with toluidine blue, the other was dried and prepared for scanning electron microscopy. The gram-stained smears demonstrated predominantly gram-positive filamentous microorganisms with an admixture of gram-positive cocci and rods. The ground sections revealed a deposit on the outer surface of the enamel, which was clearly divided into two distinctly different layers: an inner yellow opaque layer, and an outer layer of microorganisms. Scanning electron microscopy demonstrated that the deposit consisted entirely of microorganisms, and that in portions close to the enamel they were often obscured by a substance indicative of calcification. Thus the black stain found on the teeth of Hong Kong Chinese is similar in composition and structure to that reported to occur in other populations. The black stain is a special type of dental plaque characterized by its simple flora and its tendency to calcify

Community assessment of tropical tree biomass:challenges and opportunities for REDD+

BACKGROUND: REDD+ programs rely on accurate forest carbon monitoring. Several REDD+ projects have recently shown that local communities can monitor above ground biomass as well as external professionals, but at lower costs. However, the precision and accuracy of carbon monitoring conducted by local communities have rarely been assessed in the tropics. The aim of this study was to investigate different sources of error in tree biomass measurements conducted by community monitors and determine the effect on biomass estimates. Furthermore, we explored the potential of local ecological knowledge to assess wood density and botanical identification of trees. RESULTS: Community monitors were able to measure tree DBH accurately, but some large errors were found in girth measurements of large and odd-shaped trees. Monitors with experience from the logging industry performed better than monitors without previous experience. Indeed, only experienced monitors were able to discriminate trees with low wood densities. Local ecological knowledge did not allow consistent tree identification across monitors. CONCLUSION: Future REDD+ programmes may benefit from the systematic training of local monitors in tree DBH measurement, with special attention given to large and odd-shaped trees. A better understanding of traditional classification systems and concepts is required for local tree identifications and wood density estimates to become useful in monitoring of biomass and tree diversity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13021-015-0028-3) contains supplementary material, which is available to authorized users

The Microvasculature of Human Oral Mucosa Using Vascular Corrosion Casts and India Ink Injection I. Tongue Papillae

The microvasculature of human tongue papillae originating from 9 males and 6 females, aged 0.5 to 2 years was studied by scanning electron microscopy (SEM) of vascular corrosion casts and by light microscopy (LM) of India ink injected specimens. All papillae showed a microvasculature characterized by primary, secondary and tertiary capillary loops. In the filiform papillae the loops were generally arranged in a corolla-like pattern with the tertiary loops demonstrating a hair-pin shape. The fungiform papillae showed basically a similar architectural pattern although the loops were somewhat more compact and complex in structure. A small, shallow depression of the tertiary loops at the top of these papillae was found to be occupied by a prominent rete ridge of the surface epithelium. There was a gradual transition from filiform to foliate papillae, the latter appearing as rows of coalesced filiform papillae. The circumvallate papillae easily identified by the surrounding furrow showed a rather complex and compact pattern of capillary loops of which typical hair-pin shaped tertiary loops dominated the periphery of the papilla. Small grooves or depressions in the vascular network were found to be occupied by rete ridges of the overlying mucosal epithelium

Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data

OBJECTIVE: A retrospective analysis of laboratory data to investigate the isolation of Staphylococcus aureus from the oral cavity and facial area in specimens submitted to a regional diagnostic oral microbiology laboratory. METHODS: A hand search of laboratory records for a three-year period (1998-2000) was performed for specimens submitted to the regional diagnostic oral microbiology laboratory based at Glasgow Dental Hospital and School. Data were collected from forms where S. aureus was isolated. These data included demographics, referral source, specimen type, methicillin susceptibility and clinical details. RESULTS: For the period 1998-2000, there were 5,005 specimens submitted to the laboratory. S. aureus was isolated from 1,017 specimens, of which 967 (95%) were sensitive to methicillin (MSSA) and 50 (5%) were resistant to methicillin (MRSA). The 1,017 specimens were provided from 615 patients. MRSA was isolated from 37 (6%) of patients. There was an increasing incidence of S. aureus with age, particularly in the greater than 70 years age group. The most common specimen from which MSSA was isolated was an oral rinse (38%) whilst for MRSA isolates this was a tongue swab (28%). The clinical condition most commonly reported for MSSA isolates was angular cheilitis (22%). Erythema, swelling, pain or burning of the oral mucosa was the clinical condition most commonly reported for MRSA isolates (16%). Patients from whom the MSSA isolates were recovered were most commonly (55%) seen in the oral medicine clinic at the dental hospital, whilst patients with MRSA were more commonly seen in primary care settings such as nursing homes, hospices and general dental practice (51%). CONCLUSION: In line with more recent surveys, this retrospective study suggests that S. aureus may be a more frequent isolate from the oral cavity than hitherto suspected. A small proportion of the S. aureus isolates were MRSA. There were insufficient data available to determine whether the S. aureus isolates were colonising or infecting the oral cavity. However, the role of S. aureus in several diseases of the oral mucosa merits further investigation

The value and opportunities of community-and citizen-based approaches to tropical forest biodiversity monitoring

The biodiversity sourcebook is accessible in pdf format for free from:•GOFC-GOLD Land Cover Office website: http://www.gofcgold.wur.nl/sites/gofcgold-geobon_biodiversitysourcebook.php•GEO BON website:http://geobon.org

Dental plaque as a biofilm and a microbial community – implications for health and disease

Dental plaque is a structurally- and functionally-organized biofilm. Plaque forms in an ordered way and has a diverse microbial composition that, in health, remains relatively stable over time (microbial homeostasis). The predominant species from diseased sites are different from those found in healthy sites, although the putative pathogens can often be detected in low numbers at normal sites. In dental caries, there is a shift toward community dominance by acidogenic and acid-tolerating species such as mutans streptococci and lactobacilli, although other species with relevant traits may be involved. Strategies to control caries could include inhibition of biofilm development (e.g. prevention of attachment of cariogenic bacteria, manipulation of cell signaling mechanisms, delivery of effective antimicrobials, etc.), or enhancement of the host defenses. Additionally, these more conventional approaches could be augmented by interference with the factors that enable the cariogenic bacteria to escape from the normal homeostatic mechanisms that restrict their growth in plaque and out compete the organisms associated with health. Evidence suggests that regular conditions of low pH in plaque select for mutans streptococci and lactobacilli. Therefore, the suppression of sugar catabolism and acid production by the use of metabolic inhibitors and non-fermentable artificial sweeteners in snacks, or the stimulation of saliva flow, could assist in the maintenance of homeostasis in plaque. Arguments will be presented that an appreciation of ecological principles will enable a more holistic approach to be taken in caries control

Respiratory disease and the role of oral bacteria

The relationship between oral health and systemic conditions, including the association between poor oral hygiene, periodontal disease, and respiratory disease, has been increasingly debated over recent decades. A considerable number of hypotheses have sought to explain the possible role of oral bacteria in the pathogenesis of respiratory diseases, and some clinical and epidemiological studies have found results favoring such an association. This review discusses the effect of oral bacteria on respiratory disease, briefly introduces the putative biological mechanisms involved, and the main factors that could contribute to this relationship. It also describes the role of oral care for individuals who are vulnerable to respiratory infections

Ageing exacerbates damage of systemic and salivary neutrophils from patients presenting Candida-related denture stomatitis

<p>Abstract</p> <p>Background</p> <p>Ageing leads to a decline in the function of the immune system, increasing the body's susceptibility to infections through the impairment of T-cells, macrophages, neutrophils and dendritic cells Denture stomatitis is a primary oral disease affecting elderly denture wearers. The major etiologic factor involved in this pathology is the infection by <it>Candida albicans</it>, an opportunistic pathogen that causes local and disseminated diseases in immunosuppressed humans. Neutrophils play a critical role in the immune response against <it>C. albicans </it>and are continually present in the salivary fluid and in the blood. The aim of this study was to determine ageing-related changes in salivary and blood neutrophils and their potential implications in <it>Candida</it>-related denture stomatitis.</p> <p>Results</p> <p>Our results showed a lower number of neutrophils in the saliva from patients presenting <it>Candida</it>-related denture stomatitis in comparison to their matched controls. Furthermore, fewer neutrophils were isolated from the saliva of aged control individuals in comparison to matched younger subjects. CXCR1, CD62L and CD11b expression were significantly greater on systemic neutrophils from younger control individuals. Elderly individuals showed more apoptotic salivary neutrophils and lower GM-CSF levels than younger ones, regardless of the occurrence of <it>Candida </it>infection. On the other hand, CXCL-8 concentrations were higher in the saliva from elderly individuals. Besides, TNF-α was detected at elevated levels in the saliva from infected elderly subjects. Salivary neutrophils from elderly and young patients presented impaired phagocytic activity against <it>C. albicans</it>. However, just systemic neutrophils from elderly showed decreased phagocytosis when compared to the younger ones, regardless of the occurrence of infection. In addition, neutrophils from aged individuals and young patients presented low fungicidal activity.</p> <p>Conclusion</p> <p>The data suggests that the <it>Candida </it>related-denture stomatitis is associated to neutrophils function deficiency, and ageing drastically appears to alter important characteristics of such cells, facilitating the establishment of this infection.</p