Production and properties of adhesin-free gingipain proteinase RgpA.

The Arg-specific gingipains of Porphyromonas gingivalis RgpA and RgpB have 97% identical sequences in their catalytic domains yet their propeptides are only 76% identical. RgpA isolates as a proteinase-adhesin complex (HRgpA) which hinders direct kinetic comparison of RgpAcat as a monomer with monomeric RgpB. We tested modifications of rgpA identifying a variant that enabled us to isolate histidine-tagged monomeric RgpA (rRgpAH). Kinetic comparisons between rRgpAH and RgpB used benzoyl-L-Arg-4-nitroanilide with and without cysteine and glycylglycine acceptor molecules. With no glycylglycine, values of Km, Vmax, kcat and kcat/Km for each enzyme were similar, but with glycylglycine Km decreased, Vmax increased and kcat increased ~ twofold for RgpB but ~ sixfold for rRgpAH. The kcat/Km for rRgpAH was unchanged whereas that of RgpB more than halved. Recombinant RgpA propeptide inhibited rRgpAH and RgpB with Ki 13 nM and 15 nM Ki respectively slightly more effectively than RgpB propeptide which inhibited rRgpAH and RgpB with Ki 22 nM and 29 nM respectively (p < 0.0001); a result that may be attributable to the divergent propeptide sequences. Overall, the data for rRgpAH reflected observations previously made by others using HRgpA, indicating rRgpAH fidelity and confirming the first production and isolation of functional affinity tagged RgpA.

Psychoacoustic Similarity Judgments in Expert Rappers and Laypersons.

This study sought to determine whether rap expertise is associated with enhanced knowledge of psychoacoustic similarity. Using a stimulus composed of pseudo-word assonantal half-rhyme triplets (e.g., freet/speet//yeek), expert improvisational rap lyricists were compared to laypersons (non-lyricists) in their judgments of half-rhyme acceptability. According to both a perception-based and a linguistic feature-based measure of psychoacoustic similarity, lyricists were distinct from non-lyricists in the rates at which they found half-rhymes acceptable, and in how group responses were correlated with the similarity measures. Data indicate that, compared to non-lyricists, lyricists' half-rhyme acceptance rates are more highly correlated with linguistic features that have more robust perceptual cues. Evidence suggests that lyricists and non-lyricists employ different strategies for determining the acceptability of half-rhymes, and that lyricists might be more sensitive or attuned to similar aspects of speech sounds.

National Survey to Describe the Current Patterns of Procedural Sedation Practices Among Pediatric Emergency Medicine Practitioners in the United States.

OBJECTIVE: Pediatric procedural sedation (PPS) is used to maintain children's safety, comfort, and cooperation during emergency department procedures. Our objective was to gather data describing PPS practice across the United States to highlight the variations in practice and adherence to National Guidelines. METHODS: We performed a nationwide survey of PPS practitioners using a secure web-based software program. A link to the survey was sent to all subscribers of a pediatric emergency medicine listserv. We collected participant demographics, their PPS approach for personnel, monitoring, equipment, postsedation observation, and side effects, as well as providers' medication preferences for 3 common PPS scenarios. RESULTS: We received 211 completed surveys from 34 States. There were 20.6% respondents that were based in New York, 83.4% were pediatric emergency medicine attendings, and 91.7% were based in the United States teaching hospitals. Our participants learned PPS by various methods, most commonly: observation of at least 10 PPS (29.9%); self-study (24.8%); and classroom lectures (24.5%). Seventy-seven percent of our participants reported no body mass index cutoff to do PPS. There were 31.5% of our participants that observe children after PPS up to 1 hour, 30.1% up to 2 hours. There were 67.7% of the PPS providers that were a separate person from the practitioner doing the procedure, and 98.2% required a separate trained nurse to be present for monitoring. There were 92.6% of PPS providers that measure end-tidal carbon dioxide (ETCO2) during the sedation. Most PPS providers reported having no reversal agents (71.4%) and no defibrillator (65.9%) at bedside. For the abscess drainage scenario, 22% of participants preferred local anesthetic alone, and 22.5% preferred utilizing local anesthetic in combination with intravenous ketamine. For a forearm fracture reduction scenario, 62.8% of participants would choose intravenous ketamine alone. For the laceration repair scenario, the most favored drug combination was local anesthesia + intranasal midazolam by 39.8% of participants. CONCLUSIONS: Our study demonstrates a wide variability in several aspects of PPS and low adherence to national PPS guidelines.

Prehospital Disaster Triage Does Not Predict Pediatric Outcomes: Comparing the Criteria Outcomes Tool to Three Mass-Casualty Incident Triage Algorithms.

INTRODUCTION: It remains unclear which mass-casualty incident (MCI) triage tool best predicts outcomes for child disaster victims. STUDY OBJECTIVES: The primary objective of this study was to compare triage outcomes of Simple Triage and Rapid Treatment (START), modified START, and CareFlight in pediatric patients to an outcomes-based gold standard using the Criteria Outcomes Tool (COT). The secondary outcomes were sensitivity, specificity, under-triage, over-triage, and overall accuracy at each level for each MCI triage algorithm. METHODS: Singleton trauma patients under 16 years of age with complete prehospital, emergency department (ED), and in-patient data were identified in the 2007-2009 National Trauma Data Bank (NTDB). The COT outcomes and procedures were translated into ICD-9 procedure codes with added timing criteria. Gold standard triage levels were assigned using the COT based on outcomes, including mortality, injury type, admission to the hospital, and surgical procedures. Comparison triage levels were determined based on algorithmic depictions of the three MCI triage tools. RESULTS: A total of 31,093 patients with complete data were identified from the NTDB. The COT was applied to these patients, and the breakdown of gold standard triage levels, based on their actual clinical outcomes, was: 17,333 (55.7%) GREEN; 11,587 (37.3%) YELLOW; 1,572 (5.1%) RED; and 601 (1.9%) BLACK. CareFlight had the best sensitivity for predicting COT outcomes for BLACK (83% [95% confidence interval, 80%-86%]) and GREEN patients (79% [95% CI, 79%-80%]) and the best specificity for RED patients (89% [95% CI, 89%-90%]). CONCLUSION: Among three prehospital MCI triage tools, CareFlight had the best performance for correlating with outcomes in the COT. Overall, none of three tools had good test characteristics for predicting pediatric patient needs for surgical procedures or hospital admission.

Porphyromonas gingivalis laboratory strains and clinical isolates exhibit different distribution of cell surface and secreted gingipains.

Background: The cell-surface cysteine proteinases RgpA, RgpB (Arg-gingipain), and Kgp (Lys-gingipain) are major virulence factors of P. gingivalis, a keystone pathogen in the development of destructive periodontal disease. The gingipains function as proteinases and transpeptidases utilising small peptides such as glycylglycine as acceptor molecules. However, the characteristics of the gingipains from most P. gingivalis strains have not been determined. Methods: We determined the phenotypes of a panel of P. gingivalis laboratory strains and global clinical isolates with respect to growth on blood agar plus whole-cell and vesicle-free culture supernatant (VFSN) Arg- and Lys-specific proteinase activities. Results: The P. gingivalis isolates exhibited different growth characteristics and hydrolysis of haemoglobin in solid media. Whole-cell Arg-gingipain Vmax varied 5.8-fold and the whole cell Lys-gingipain Vmax varied 2.1-fold across the strains. Furthermore, the P. gingivalis strains showed more than 107-fold variance in soluble Arg-gingipain activity in VFSN and more than 371-fold variance in soluble Lys-gingipain activity in VFSN. Glycylglycine and cysteine stimulated Arg- and Lys-specific cleavage activities of all strains. The stimulation by cysteine was in addition to its redox effect consistent with both glycylglycine and cysteine promoting transpeptidation. Conclusion: The global P. gingivalis clinical isolates exhibit different Arg- and Lys­gingipain activities with substantial variability in the level of soluble proteinases released into the environment.

Auditory rhyme processing in expert freestyle rap lyricists and novices: An ERP study.

Music and language processing share and sometimes compete for brain resources. An extreme case of such shared processing occurs in improvised rap music, in which performers, or 'lyricists', combine rhyming, rhythmic, and semantic structures of language with musical rhythm, harmony, and phrasing to create integrally meaningful musical expressions. We used event-related potentials (ERPs) to investigate how auditory rhyme sequence processing differed between expert lyricists and non-lyricists. Participants listened to rhythmically presented pseudo-word triplets each of which terminated in a full-rhyme (e.g., STEEK, PREEK; FLEEK), half-rhyme (e.g., STEEK, PREEK; FREET), or non-rhyme (e.g., STEEK, PREEK; YAME), then judged each sequence in its aesthetic (Do you 'like' the rhyme?) or technical (Is the rhyme 'perfect'?) aspect. Phonological N450 showed rhyming effects between conditions (i.e., non vs. full; half vs. full; non vs. half) similarly across groups in parietal electrodes. However, concurrent activity in frontocentral electrodes showed left-laterality in non-lyricists, but not lyricists. Furthermore, non-lyricists' responses to the three conditions were distinct in morphology and amplitude at left-hemisphere electrodes with no condition difference at right-hemisphere electrodes, while lyricists' responses to half-rhymes they deemed unsatisfactory were similar to full-rhyme at left-hemisphere electrodes, and similar to non-rhyme at right-hemisphere electrodes. The CNV response observed while waiting for the second and third pseudo-word in the sequence was more enhanced to aesthetic rhyme judgments tasks than to technical rhyme judgment tasks in non-lyricists, suggesting their investment of greater effort for aesthetic rhyme judgments. No task effects were observed in lyricists, suggesting that aesthetic and technical rhyme judgments may engage the same processes for experts. Overall, our findings suggest that extensive practice of improvised lyricism may uniquely encourage the neuroplasticity of integrated linguistic and musical feature processing in the brain.

A novel streamlined trauma response team training improves imaging efficiency for pediatric blunt abdominal trauma patients.

BACKGROUND/PURPOSE: The morbidity and mortality of children with traumatic injuries are directly related to the time to definitive management of their injuries. Imaging studies are used in the trauma evaluation to determine the injury type and severity. The goal of this project is to determine if a formal streamlined trauma response improves efficiency in pediatric blunt trauma by evaluating time to acquisition of imaging studies and definitive management. METHODS: This study is a chart review of patients <18 years who presented to a pediatric trauma center following blunt trauma requiring trauma team activation. 413 records were reviewed to determine if training changed the efficiency of CT acquisition and 652 were evaluated for FAST efficiency. The metrics used for comparison were time from ED arrival to CT image, FAST, and disposition. RESULTS: Time from arrival to CT acquisition decreased from 37 (SD 23) to 28 (SD27) min (p < 0.05) after implementation. The proportion of FAST scans increased from 315 (63.5%) to 337 (80.8%) and the time to FAST decreased from 18 (SD15) to 8 (SD10) min (p < 0.05). The time to operating room (OR) decreased after implementation. CONCLUSION: The implementation of a streamlined trauma team approach is associated with both decreased time to CT, FAST, OR, and an increased proportion of FAST scans in the pediatric trauma evaluation. This could result in the rapid identification of injuries, faster disposition from the ED, and potentially improve outcomes in bluntly injured children. TYPE OF STUDY: Therapeutic LEVEL OF EVIDENCE: Level III.

Porphyromonas gingivalis Gingipains Display Transpeptidation Activity.

Porphyromonas gingivalis is a keystone periodontal pathogen that has been associated with autoimmune disorders. The cell surface proteases Lys-gingipain (Kgp) and Arg-gingipains (RgpA and RgpB) are major virulence factors, and their proteolytic activity is enhanced by small peptides such as glycylglycine (GlyGly). The reaction kinetics suggested that GlyGly may function as an acceptor molecule for gingipain-catalyzed transpeptidation. Purified gingipains and P. gingivalis whole cells were used to digest selected substrates including human hemoglobin in the presence or absence of peptide acceptors. Mass spectrometric analysis of the substrates digested with gingipains in the presence of GlyGly showed that transpeptidation outcompeted hydrolysis, whereas the trypsin-digested controls exhibited predominantly hydrolysis activity. The transpeptidation levels increased with increasing concentration of GlyGly. Purified gingipains and whole cells exhibited extensive transpeptidation activities on human hemoglobin. All hemoglobin cleavage sites were found to be suitable for GlyGly transpeptidation, and this transpeptidation enhanced hemoglobin digestion. The transpeptidation products were often more abundant than the corresponding hydrolysis products. In the absence of GlyGly, hemoglobin peptides produced during digestion were utilized as acceptors leading to the detection of up to 116 different transpeptidation products in a single reaction. P. gingivalis cells were able to digest hemoglobin faster when acceptor peptides derived from human serum albumin were included in the reaction, suggesting that gingipain-catalyzed transpeptidation may be relevant for substrates encountered in vivo. The transpeptidation of host proteins in vivo may potentially lead to the breakdown of immunological tolerance, culminating in autoimmune reactions.

A Systematic Review and Meta-analysis of Thrombotic Events Following Endovenous Thermal Ablation of the Great Saphenous Vein.

OBJECTIVES: A systematic review and meta-analysis was performed to determine the incidence of thrombotic events following great saphenous vein (GSV) endovenous thermal ablation (EVTA). METHODS: MEDLINE, Embase and conference abstracts were searched. Eligible studies were randomised controlled trials and case series that included at least 100 patients who underwent GSV EVTA (laser ablation or radiofrequency ablation [RFA]) with duplex ultrasound (DUS) within 30 days. The systematic review focused on the complications of endovenous heat induced thrombosis (EHIT), deep venous thrombosis (DVT), and pulmonary embolism (PE). The primary outcome for the meta-analysis was deep venous thrombotic events which were defined as DVT or EHIT Type 2, 3, or 4. Secondary outcomes for the meta-analysis were EHIT Type 2, 3, or 4, DVT and PE. Subgroup analyses were performed for both the RFA and EVLA groups. Pooled proportions were calculated using random effects modelling. RESULTS: Fifty-two studies (16,398 patients) were included. Thrombotic complications occurred infrequently. Deep venous thrombotic events occurred in 1.7% of cases (95% CI 0.9-2.7%) (25 studies; 10,012 patients; 274 events). EHIT Type 2, 3, or 4 occurred in 1.4% of cases (95% CI 0.8-2.3%) (26 studies; 10,225 patients; 249 events). DVT occurred in 0.3% of cases (95% CI = 0.2%-0.5%) (49 studies; 15,676 patients; 48 events). PE occurred in 0.1% of cases (95% CI = 0.1-0.2%) (29 studies; 8223 patients; 3 events). Similar results were found when the RFA and EVLA groups were analysed separately. CONCLUSION: Thrombotic events occur infrequently following GSV EVTA. Given the large numbers of procedures worldwide and the potential for serious consequences, further research is needed on the burden of these complications and their management.

Devil within: an incidental and rare finding of an extragonandal retroperitoneal germ cell teratoma carcinoid tumour.

Extragonadal germ cell tumours (GCTs) are uncommon neoplasms comprising approximately 2%-5% of all GCTs. Of these, approximately 30%-40% occurs as primary retroperitoneal GCTs. This case report details the presentation, diagnosis and management of a 53-year-old man presenting with an incidental finding of a primary extragonadal retroperitoneal teratoma with carcinoid transformation.

Analysis of Patient Visits and Collections After Opening a Satellite Pediatric Emergency Department.

OBJECTIVE: Satellite pediatric emergency departments (PEDs) have emerged as a strategy to increase patient capacity. We sought to determine the impact on patient visits, physician fee collections, and value of emergency department (ED) time at the primary PED after opening a nearby satellite PED. We also illustrate the spatial distribution of patient demographics and overlapping catchment areas for the primary and satellite PEDs using geographical information system. METHODS: A structured, financial retrospective review was conducted. Aggregate patient demographic data and billing data were collected regarding physician fee charges, collections, and patient visits for both PEDs. All ED visits from January 2009 to December 2013 were analyzed. Geographical information system mapping using ArcGIS mapped ED patient visits. RESULTS: Patient visits at the primary PED were 53,050 in 2009 before the satellite PED opened. The primary PED visits increased after opening the satellite PED to 55,932 in 2013. The satellite PED visits increased to 21,590 in 2013. Collections per visit at the primary PED decreased from $105.13 per visit in 2011 to $86.91 per visit in 2013. Total collections at the satellite PED decreased per visit from $155.41 per visit in 2011 to $128.53 per visit in 2013. CONCLUSIONS: After opening a nearby satellite PED, patient visits at the primary PED did not substantially decrease, suggesting that there was a previously unrecognized demand for PED services. The collections per ED visit were greater at the satellite ED, likely due to a higher collection rate.

Cost-effectiveness of Strategies for Offering Influenza Vaccine in the Pediatric Emergency Department.

Importance: Influenza is a significant public health burden, causing morbidity and mortality in children, yet vaccination rates remain low. Vaccination in the pediatric emergency department (PED) setting may be beneficial but, to date, has not been proven to be cost-effective. Objective: To compare the cost-effectiveness of 4 strategies for PED-based influenza vaccine: offering vaccine to all patients, only to patients younger than 5 years, only to high-risk patients (all ages), or to no patients. Design, Setting, and Participants: Using commercial decision analysis software, a cost-effectiveness analysis was performed from January 1, 2016, to June 1, 2017, to compare influenza vaccine strategies at a tertiary, urban, freestanding PED with an estimated 60 000 visits per year among a hypothetical cohort of children visiting the above PED during influenza season. Sensitivity analyses estimated the effect of uncertainties across a variety of input variables (eg, influenza prevalence, vaccine price and effectiveness, and costs of complications). Main Outcomes and Measures: The primary outcomes were cost and incremental cost-effectiveness ratio in dollars per influenza case averted. Secondary outcomes included total societal costs, hospitalizations and deaths averted, and quality-adjusted life-years gained. Results: Offering influenza vaccine to all eligible patients has the lowest cost, at $114.45 (95% CI, $55.48-$245.45) per case of influenza averted. This strategy saves $33.51 (95% CI, $18-$62) per case averted compared with no vaccination, and averages 27 fewer cases of influenza per 1000 patients. Offering vaccine to all patients resulted in 0.72 days (95% CI, 0.18-1.78 days) of quality-adjusted life-years lost, whereas offering to none resulted in 0.91 days (95% CI, 0.25-2.2 days) of quality-adjusted life-years lost. In sensitivity analyses, this strategy remains robustly cost-effective across a wide range of assumptions. In addition to being the most cost-effective strategy regardless of age or risk status, routine vaccination in the PED results in a net societal monetary benefit under many circumstances. In Monte Carlo analysis, offering vaccine to all patients was superior to other strategies in at least 99.8% of cases. Conclusions and Relevance: Although few PEDs routinely offer influenza vaccination, doing so appears to be cost-effective, with the potential to significantly reduce the economic (and patient) burden of pediatric influenza.

Porphyromonas gingivalis Uses Specific Domain Rearrangements and Allelic Exchange to Generate Diversity in Surface Virulence Factors.

Porphyromonas gingivalis is a keystone pathogen of chronic periodontitis. The virulence of P. gingivalis is reported to be strain related and there are currently a number of strain typing schemes based on variation in capsular polysaccharide, the major and minor fimbriae and adhesin domains of Lys-gingipain (Kgp), amongst other surface proteins. P. gingivalis can exchange chromosomal DNA between strains by natural competence and conjugation. The aim of this study was to determine the genetic variability of P. gingivalis strains sourced from international locations over a 25-year period and to determine if variability in surface virulence factors has a phylogenetic basis. Whole genome sequencing was performed on 13 strains and comparison made to 10 previously sequenced strains. A single nucleotide polymorphism-based phylogenetic analysis demonstrated a shallow tri-lobed phylogeny. There was a high level of reticulation in the phylogenetic network, demonstrating extensive horizontal gene transfer between the strains. Two highly conserved variants of the catalytic domain of the major virulence factor the Kgp proteinase (KgpcatI and KgpcatII) were found. There were three variants of the fourth Kgp C-terminal cleaved adhesin domain. Specific variants of the cell surface proteins FimA, FimCDE, MfaI, RagAB, Tpr, and PrtT were also identified. The occurrence of all these variants in the P. gingivalis strains formed a mosaic that was not related to the SNP-based phylogeny. In conclusion P. gingivalis uses domain rearrangements and genetic exchange to generate diversity in specific surface virulence factors.

The Twin Evils of Concomitant Rare Pathology with Variant Anatomy: Superior Mesenteric Artery Aneurysm and a Replaced Right Hepatic Artery.

Aneurysmal degeneration of the superior mesenteric artery (SMA) is a rare clinical finding, estimated to affect <1% of the general population in postmortem studies. Due to the rare prevalence of aneurysms affecting the SMA, there are no clear or definitive published consensus guidelines for its management at presentation, with both surgical and endovascular options described. An aberrant or replaced right hepatic artery (RRHA) is thought to affect 10-15% of the population. The prevalence of both conditions presenting concomitantly is unknown, but undoubtedly even rarer. We describe the successful management of a symptomatic SMA aneurysm with an RRHA emerging from the aneurysmal sac presenting to our vascular unit. This was repaired via an open surgical approach with SMA aneurysmectomy and interposition grafting using reversed vein with preservation of RHA liver perfusion via a novel reconstruction option. This case highlights the challenge that visceral aneurysms pose, especially when simple or orthodox reconstruction options are limited due to rare or unusual anatomy.

PG1058 Is a Novel Multidomain Protein Component of the Bacterial Type IX Secretion System.

Porphyromonas gingivalis utilises the Bacteroidetes-specific type IX secretion system (T9SS) to export proteins across the outer membrane (OM), including virulence factors such as the gingipains. The secreted proteins have a conserved carboxy-terminal domain essential for type IX secretion that is cleaved upon export. In P. gingivalis the T9SS substrates undergo glycosylation with anionic lipopolysaccharide (A-LPS) and are attached to the OM. In this study, comparative analyses of 24 Bacteroidetes genomes identified ten putative novel components of the T9SS in P. gingivalis, one of which was PG1058. Computer modelling of the PG1058 structure predicted a novel N- to C-terminal architecture comprising a tetratricopeptide repeat (TPR) domain, a ß-propeller domain, a carboxypeptidase regulatory domain-like fold (CRD) and an OmpA_C-like putative peptidoglycan binding domain. Inactivation of pg1058 in P. gingivalis resulted in loss of both colonial pigmentation and surface-associated proteolytic activity; a phenotype common to T9SS mutants. Immunoblot and LC-MS/MS analyses of subcellular fractions revealed T9SS substrates accumulated within the pg1058 mutant periplasm whilst whole-cell ELISA showed the Kgp gingipain was absent from the cell surface, confirming perturbed T9SS function. Immunoblot, TEM and whole-cell ELISA analyses indicated A-LPS was produced and present on the pg1058 mutant cell surface although it was not linked to T9SS substrate proteins. This indicated that PG1058 is crucial for export of T9SS substrates but not for the translocation of A-LPS. PG1058 is a predicted lipoprotein and was localised to the periplasmic side of the OM using whole-cell ELISA, immunoblot and LC-MS/MS analyses of subcellular fractions. The structural prediction and localisation of PG1058 suggests that it may have a role as an essential scaffold linking the periplasmic and OM components of the T9SS.

Casein Phosphopeptide-Amorphous Calcium Phosphate Nanocomplexes: A Structural Model.

Tryptic digestion of the calcium-sensitive caseins yields casein phosphopeptides (CPP) that contain clusters of phosphorylated seryl residues. The CPP stabilize calcium and phosphate ions through the formation of complexes. The calcium phosphate in these complexes is biologically available for intestinal absorption and remineralization of subsurface lesions in tooth enamel. We have studied the structure of the complexes formed by the CPP with calcium phosphate using a variety of nuclear magnetic resonance (NMR) techniques. Translational diffusion measurements indicated that the ß-CN(1-25)-ACP nanocomplex has a hydrodynamic radius of 1.526 ± 0.044 nm at pH 6.0, which increases to 1.923 ± 0.082 nm at pH 9.0. (1)H NMR spectra were well resolved, and (3)JH(N)-H(α) measurements ranged from a low of 5.5 Hz to a high of 8.1 Hz. Total correlation spectroscopy and nuclear Overhauser effect spectroscopy spectra were acquired and sequentially assigned. Experiments described in this paper have allowed the development of a structural model of the ß-CN(1-25)-amorphous calcium phosphate nanocomplex.

The Interactions of CPP-ACP with Saliva.

The repair of early dental caries lesions has been demonstrated by the application of the remineralisation technology based on casein phosphopeptide-stabilised amorphous calcium phosphate complexes (CPP-ACP). These complexes consist of an amorphous calcium phosphate mineral phase stabilised and encapsulated by the self-assembly of milk-derived phosphopeptides. During topical application of CPP-ACP complexes in the oral cavity, the CPP encounters the enamel pellicle consisting of salivary proteins and peptides. However the interactions of the CPP with the enamel salivary pellicle are not known. The studies presented here reveal that the predominant peptides of CPP-ACP complexes do interact with specific salivary proteins and peptides of the enamel pellicle, and provide a mechanism by which the CPP-ACP complexes are localised at the tooth surface to promote remineralisation.

Influence of a low-carbohydrate diet on endothelial microvesicles in overweight women.

Low-carbohydrate diets (LCD) are increasing in popularity, but their effect on vascular health has been questioned. Endothelial microvesicles (EMV) are membrane-derived vesicles with the potential to act as a sensitive prognostic biomarker of vascular health and endothelial function. The aim of this study was to examine the influence of a LCD on EMV and other endothelial biomarkers of protein origin. Twenty-four overweight women (age, 48.4 ± 0.6 years; height, 1.60 ± 0.07 m; body mass, 76.5 ± 9.1 kg; body mass index, 28.1 ± 2.7 kg·m(-2); waist circumference, 84.1 ± 7.4 cm; mean ± standard deviation) were randomised to either 24 weeks on their normal diet (ND) or a LCD, after which they crossed over to 24 weeks on the alternative diet. Participants were assisted in reducing carbohydrate intake, but not below 40 g·day(-1). Body composition and endothelial biomarkers were assessed at the crossover point and at the end of the study. Daily carbohydrate intake (87 ± 7 versus 179 ± 11 g) and the percentage of energy derived from carbohydrate (29% versus 44%) were lower (p < 0.05) on the LCD compared to the ND, but absolute fat and saturated fat intake were unchanged. Body mass and waist circumference were 3.7 ± 0.8 kg and 3.5 ± 1.0 cm lower (p < 0.05), respectively, after the LCD compared with the ND phases. CD31(+)CD41(-)EMV, soluble (s) thrombomodulin, sE-selectin, sP-selectin, serum amyloid A and C-reactive protein were lower (p < 0.05) after the LCD compared to the ND, but serum lipids and apolipoproteins were not different. EMV along with a range of endothelial and inflammatory biomarkers are reduced by a LCD that involves modest weight loss.

A therapeutic Porphyromonas gingivalis gingipain vaccine induces neutralising IgG1 antibodies that protect against experimental periodontitis.

Porphyromonas gingivalis infected mice with an established P. gingivalis-specific inflammatory immune response were protected from developing alveolar bone resorption by therapeutic vaccination with a chimera (KAS2-A1) immunogen targeting the major virulence factors of the bacterium, the gingipain proteinases. Protection was characterised by an antigen-specific IgG1 isotype antibody and Th2 cell response. Adoptive transfer of KAS2-A1-specific IgG1 or IgG2 expressing B cells confirmed that IgG1-mediated protection. Furthermore, parenteral or intraoral administration of KAS2-A1-specific polyclonal antibodies protected against the development of P. gingivalis-induced bone resorption. The KAS2-A1-specific antibodies neutralised the gingipains by inhibiting: proteolytic activity, binding to host cells/proteins and co-aggregation with other periodontal bacteria. Combining key gingipain sequences into a chimera vaccine produced an effective therapeutic intervention that protected against P. gingivalis-induced periodontitis.