Precursor ion scanning for detection and structural characterization of heterogeneous glycopeptide mixtures

AbstractThe structure of N-linked glycans is determined by a complex, anabolic, intracellular pathway but the exact role of individual glycans is not always clear. Characterization of carbohydrates attached to glycoproteins is essential to aid understanding of this complex area of biology. Specific mass spectral detection of glycopeptides from protein digests may be achieved by on-line HPLC-MS, with selected ion monitoring (SIM) for diagnostic product ions generated by cone voltage fragmentation, or by precursor ion scanning for terminal saccharide product ions, which can yield the same information more rapidly. When glycosylation is heterogeneous, however, these approaches can result in spectra that are complex and poorly resolved. We have developed methodology, based around precursor ion scanning for ions of high m/z, that allows site specific detection and structural characterization of glycans at high sensitivity and resolution. These methods have been developed using the standard glycoprotein, fetuin, and subsequently applied to the analysis of the N-linked glycans attached to the scrapie-associated prion protein, PrPSc. These glycans are highly heterogeneous and over 30 structures have been identified and characterized site specifically. Product ion spectra have been obtained on many glycopeptides confirming structure assignments. The glycans are highly fucosylated and carry Lewis X or sialyl Lewis X epitopes and the structures are in-line with previous results. [Abbreviations: Hex–Hexose, C6H12O6 carbohydrates, including mannnose and galactose; HexNAc—N-acetylhexosamine, C8H15NO6 carbohydrates, including N-acetylglucosamine and N-acetylgalactosamine; GlcNAc—N-acetylglucosamine; GalNAc—N-acetylgalactosamine; Fuc–Fucose; NeuAC—N-acetylneuraminic acid or sialic acid; TSE—Transmissible Spongiform Encephalopathy.

Caries associated with orthodontic care part 1: aetiology, prevalence and prevention

The prevalence of demineralization, or enamel caries which is the first clinically recognizable stage of caries, has been reported to be as high as 73% during fixed appliance treatment. It is recognized that wearing an orthodontic appliance increases the caries risk of the individual. The orthodontist can effectively reduce demineralization by applying fluoride varnish at each visit. Selecting patients on their oral hygiene clearly is one factor which can prevent patients suffering from demineralization. Excellent home care with optimal use of fluoride will also help prevent the condition. There is little evidence that fluoride-releasing materials used for bonding orthodontic appliances offer protection from demineralization. The first of these two papers describes the aetiology, prevalence and prevention of demineralization associated with orthodontic care. The second paper will describe the treatments available to manage caries focusing on demineralization post orthodontic treatment. CPD/Clinical Relevance: Demineralization is the most common complication of orthodontic care. The clinician should understand how to prevent this

What are the health impacts of nicotine and tobacco products on young people?

Design Narrative review. Review question What are the implications of new nicotine and tobacco products on adolescent health? Products E-cigarettes and oral nicotine products such as pouches, lozenges, tablets, gum, and gummies. Results These products can be addictive and can cause respiratory, cardiovascular and oral potential health problems. They also have effects on brain development. Products are attractive to adolescents, with more than 1:10 American adolescents uses them. Conclusions The use of nicotine and tobacco products by adolescents puts their health at risk and may, in some instances, lead to nicotine addiction. Those providing healthcare for adolescents have an opportunity to provide advice and signpost people to resources to help them stop using such products. There is also a need for legislation to restrict the sale of e-cigarettes and tobacco products

Should we splint traumatised primary teeth?

Design Systematic review. Review question Does splinting of traumatised primary teeth improve clinical outcomes? Case selection Clinical studies published after 2003 reporting trauma (luxation, root fracture or alveolar fracture) to primary teeth, with a minimum follow-up of 6 months, were eligible for inclusion. Case reports were excluded, but case series were included. Studies reporting the outcome of splinting following avulsion injuries were excluded, as current guidance does not recommend re-implantation of teeth for these injuries. Data analysis Two researchers independently assessed the risk of bias in the included studies, with a third researcher resolving any disagreements. The same two independent researchers conducted a quality assessment of the included studies. Results Three retrospective studies met the inclusion criteria. Only one of these studies had a control group. High success rates were reported for the management of teeth with root fractures. A benefit for splinting teeth with lateral luxation was not identified. No alveolar fractures were included. Conclusions This review suggests that the outcome of the management of root fractures in primary teeth may benefit from flexible splinting. However, the evidence base is low

In-vivo validity of proximal caries detection in primary teeth, with histological validation.

BACKGROUND: Detection and diagnosis of proximal caries in primary molars is challenging. AIM: The aim of this in-vivo study was to assess the validity and reproducibility of four methods of proximal caries detection in primary molar teeth. DESIGN: Eighty-two children (5-10 yrs) were recruited. Initially 1030 proximal surfaces were examined using meticulous visual examination (ICDAS) (VE1), bitewing radiographs (RE), and a laser fluorescence pen device (LF1). Temporary tooth separation (TTS) was achieved for 447 surfaces and these were re-examined visually (VE2) and using the LF-pen (LF2). Three hundred and fifty-six teeth (542 surfaces) were subsequently extracted and provided histological validation. RESULTS: At D1 (enamel and dentine caries) diagnostic threshold, the sensitivity of VE1, RE, VE2, LF1 and LF2 examination were 0.52, 0.14, 0.75, 0.58, 0.60 and the specificity values were 0.89, 0.97, 0.88, 0.85, 0.77 respectively. At D3 (dentine caries) threshold, the sensitivity values were 0.42, 0.71, 0.49, 0.63, 0.65 respectively, while specificity was 0.93 for VE1 and VE2, and 0.98, 0.87 and 0.88 for RE, LF1 and LF2 examinations respectively. ROC analysis showed radiographic examination to be superior at D3 . CONCLUSION: Meticulous caries diagnosis (ICDAS) should be supported by radiographs for detection of dentinal proximal caries in primary molars

Esthetic judgments of palatally displaced canines 3 months postdebond after surgical exposure with either a closed or an open technique.

The aim of this study was to compare the esthetic judgments of orthodontists and laypeople regarding the appearance of palatally displaced canines 3 months after treatment with either a closed or an open surgical exposure and orthodontic alignment

The impact of dental caries on children and young people: What they have to say?

Background: Dental caries affects 60-90% of children across the world and is associated with a variety of negative impacts. Despite its ubiquity, there has been surprisingly little exploration of these impacts from the child's perspective. Aim: The aim was to allow children to describe the impact of dental caries on their daily lives and to describe the terminology they used. Design: Children, aged 5-15 years, with caries experience were purposively sampled from primary and secondary care dental clinics. Focus groups (n = 5) and in-depth interviews (n = 16) were recorded and transcribed verbatim. Data analysis took a narrative approach, and themes were derived from the data using framework analysis. Results: Pain was the main theme to emerge. Within this, three subthemes were identified: impacts related to pain, strategies adopted to reduce pain, and emotional aspects resulting from pain. A second theme was also identified relating to the aesthetic aspects of caries. Conclusion: Children as young as 5 years of age were able to competently discuss their experiences of dental caries. Participants reported a number of impacts affecting various aspects of their lives. These will be incorporated into the future development of a caries-specific measure of oral health-related quality of life