martes, 23 de mayo de 2017

The ultrastructure of subgingival dental plaque, revealed by high-resolution field emission scanning electron microscopy


  • BDJ Open 1, Article number: 15003 (2015)


OBJECTIVES/AIMS: To explore the ultrastructure of subgingival dental plaque using high-resolution field emission scanning electron microscopy (FE-SEM) and to investigate whether extracellular DNA (eDNA) could be visualised in ex vivo samples. 
MATERIALS AND METHODS: Ten patients were recruited who fulfilled the inclusion criteria (teeth requiring extraction with radiographic horizontal bone loss of over 50% and grade II/III mobility). In total, 12 teeth were extracted using a minimally traumatic technique. Roots were sectioned using a dental air turbine handpiece, under water cooling to produce 21 samples. Standard fixation and dehydration protocols were followed. For some samples, gold-labelled anti-DNA antibodies were applied before visualising biofilms by FE-SEM. 
RESULTS: High-resolution FE-SEMs of subgingival biofilm were obtained in 90% of the samples. The sectioning technique left dental plaque biofilms undisturbed. Copious amounts of extracellular material were observed in the plaque, which may have been eDNA as they had a similar appearance to labelled eDNA from in vitro studies. There was also evidence of membrane vesicles and open-ended tubular structures. Efforts to label eDNA with immune-gold antibodies were unsuccessful and eDNA was not clearly labelled. 
CONCLUSIONS: High-resolution FE-SEM images were obtained of undisturbed subgingival ex vivo dental plaque biofilms. Important structural features were observed including extracellular polymeric material, vesicles and unusual open tubule structures that may be remnants of lysed cells. The application of an eDNA immune-gold-labelling technique, previously used successfully in in vitro samples, did not clearly identify eDNA in ex vivo samples. Further studies are needed to characterise the molecular composition of the observed extracellular matrix material.

jueves, 18 de mayo de 2017






miércoles, 17 de mayo de 2017

Nail involvement in systemic sclerosis

Journal of the American Academy of Dermatology;

volume 76, Issue 6, 1115 - 1123

Background

Nail involvement has rarely been recognized in systemic sclerosis (SSc). Indeed, only a few small series have assessed nail changes in SSc, most of which are case reports.

Objective

The aims of the current case-control study were to: (1) determine the prevalence of fingernail changes in SSc; and (2) evaluate the correlation between fingernail changes and other features of SSc.

Methods

In all, 129 patients with SSc and 80 healthy control subjects underwent routine fingernail examination.

Results

The prevalence of fingernail changes was 80.6% in SSc. Patients with SSc more frequently exhibited: trachyonychia (P = .006), scleronychia (P < .0001), thickened nails (P < .0001), brachyonychia (P = .0004), parrot beaking (P < .0001), pterygium inversum unguis (P < .0001), splinter hemorrhages (P < .0001), and cuticle abnormalities (P < .0001) than healthy control subjects. The presence of fingernail changes was associated with digital ulcers (P < .0001), calcinosis cutis (P = .004), and higher values of mean nailfold videocapillaroscopy score (P = .0009).

Limitations

The cohort originated from a single center.

Conclusion

This study underlines that fingernail changes are correlated with more severe forms of SSc characterized by digital microangiopathy, including digital ulcers and calcinosis cutis. Nail changes should be systematically checked in all patients with SSc, and may be included in the American College of Rheumatology/European League Against Rheumatism classification criteria for SSc.