Cryo-EM structure of amyloid fibril formed by α-synuclein hereditary A53E mutation reveals a distinct protofilament interface.

Synucleinopathies like Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple systems atrophy (MSA), have the same pathologic feature of misfolded α-synuclein protein (α-syn) accumulation in the brain. PD patients who carry α-syn hereditary mutations tend to have earlier onset and more severe clinical symptoms than sporadic PD patients. Therefore, revealing the effect of hereditary mutations to the α-syn fibril structure can help us understand these synucleinopathies' structural basis.

A phage parasite deploys a nicking nuclease effector to inhibit viral host replication.

PLEs (phage-inducible chromosomal island-like elements) are phage parasites integrated into the chromosome of epidemic Vibrio cholerae. In response to infection by its viral host ICP1, PLE excises, replicates and hijacks ICP1 structural components for transduction. Through an unknown mechanism, PLE prevents ICP1 from transitioning to rolling circle replication (RCR), a prerequisite for efficient packaging of the viral genome.

An Enzyme-Mediated Amplification Strategy Enables Detection of β-Lactamase Activity Directly in Unprocessed Clinical Samples for Phenotypic Detection of β-Lactam Resistance.

Biochemical assays that can identify β-lactamase activity directly from patient samples have the potential to significantly improve the treatment of bacterial infections. However, current β-lactamase probes do not have the sensitivity needed to measure β-lactam resistance directly from patient samples. Here, we report the development of an instrument-free signal amplification technology, DETECT, that connects the activity of two enzymes in series to effectively amplify the activity of β-lactamase 40 000-fold, compared to the standard β-lactamase probe nitrocefin.

Dietary models for root caries.

A stepwise multiple logistic regression was computed to assess which of the nutritional variables differentiate the healthy and diseased group of participants in the Forsyth Specialized Caries Center (n = 275). Variables considered as candidates for the model included the consumption per week of sugars, starch, cheese, fruits and fruit juices, noncariogenic foods, and dairy products. Two variables--sugars and cheese--were statistically significant by the stepwise procedure.

Using a fluoride-releasing resin to reduce cervical sensitivity.

Significant research indicates that dental hypersensitivity is caused by open dentinal tubules. A review of such research is presented as well as results of a study using fluoride resin in a composite restoration to reduce sensitivity.

Gingival recession: intra-oral distribution and associated factors.

This study assesses the role of poor oral hygiene and forceful toothbrushing as risk factors for recession. As part of a cross-sectional root surface caries study, 298 subjects, 42 to 67 years of age, with at least one exposed root surface, were examined. Since 66% of the root surface exposure and practically all the abrasion was on buccal surfaces, the analyses focused only on the buccal surface.

The relative anticaries effectiveness of sodium monofluorophosphate and sodium fluoride as contained in currently available dentifrice formulations.

A 36-month double-blind clinical caries study was conducted to determine the comparative anticaries efficacy of sodium monofluorophosphate (MFP) and sodium fluoride (NaF) as incorporated in dentifrice formulations. The test dentifrices which were utilized are commercially available in the United States and all have been granted the American Dental Association Seal of Acceptance for anticaries efficacy. The study was conducted in accordance with the 1988 Guidelines of the American Dental Association Council on Dental Therapeutics.

Clinical studies on MFP/calcium containing abrasive.

Monofluorophosphate (MFP) is unique in that its calcium salt is relatively soluble. Because of this property MFP can be combined with a dicalcium dihydrate (dical) abrasive in a dentifrice formulation without loss of efficacy. It has been reported that fluoride uptake by artificial lesions in enamel and dentine is significantly greater from an MFP formulation containing dical than from an equivalent calcium-free formulation.

A critical review of the relative anticaries efficacy of sodium fluoride and sodium monofluorophosphate dentifrices.

While there is broad consensus in the research community that fluoride dentifrices provide important anticaries benefits, debate still remains as to the most efficient form of fluoride used in toothpastes. Recently, the authors of this paper collaborated as part of a scientific advisory group whose objective was to comprehensively review all clinical information available comparing the anticaries efficacy of the two agents most widely used in fluoridated toothpastes, sodium fluoride (NaF) and sodium monofluorophosphate (SMFP). This review included a detailed analysis of each published study pertinent to the question, a comprehensive meta-analysis of all available clinical findings, and an epidemiological assessment of how anticaries benefits of dentifrices may be anticipated to propagate with time.

The prevalence of root caries in a diabetic population.

The objective of this study was to assess the level of root caries in a population of diabetic adults. Diabetics are of special interest because they are alleged to be periodontally compromised and have atypical patterns of refined carbohydrate ingestion. Diabetic subjects were patients of the Joslin Diabetic Center in Boston and had significantly elevated blood glucose and glycosylated hemoglobin levels over at least a ten-year period.

CaF2 in enamel biopsies 6 weeks and 18 months after fluoride treatment.

Fluoride concentrations were studied in enamel biopsies from maxillary central incisors 6 weeks and 18 months after fluoride treatment. In the short-term study biopsies were obtained prior to and after treatment with acidic sodium or ammonium fluoride. The findings showed that large amounts of fluoride were deposited in enamel from NH4F treatment (mean concentration 84,723 ppm), indicating substantial CaF2 formation.

Reaction paper: the use of topical and systemic fluorides in the present era.

Systemic fluoride may enhance the resistance of the tooth by way of (1) an alteration in tooth morphology, and (2) a conversion of the hydroxyapatitic mineral to a fluoridated state with an attendant reduction in solubility and an enhancement of the remineralization phase of the caries process. It has been reported by a number of investigators, although it is not universally accepted, that the posterior teeth from fluoridated areas have a distinct morphology that is less susceptible to caries attack. Fluorapatite and hydroxyapatite do not differ appreciably with respect to the amount of mineral that dissolves at a specified concentration of acid.

The efficacy of a novel toothbrush design.

The single-blind study compared a novel toothbrush design (Aquafresh Flex soft, medium, and firm bristle versions) to a widely-available, standard brush with soft bristles. Subjects (n = 32-35/group, mean age = 46 yrs) were randomly assigned to the four groups and instructed to maintain their normal oral hygiene routine. Safety, as well as plaque (Turesky et al.

Association of the microbial flora of dental plaque and saliva with human root-surface caries.

Dental plaque was obtained from one or two sound root surfaces of subjects with different degrees of root-surface caries experience. From subjects with root-surface caries, plaque samples were also obtained from either one incipient or one more advanced lesion. Proportions of the total flora were determined for total streptococci and different streptococcal species, total and different Actinomyces species, and lactobacilli.

In vivo study of slow-release fluoride resin and enamel uptake.

The purpose of this study was to investigate in vivo enamel fluoride uptake of a slow-release boron trifluoride BIS-GMA resin material. Study subjects were orthodontic patients with at least one pair of permanent bicuspid teeth indicated for extraction. The material was applied to the buccal surface of the test tooth 1 month prior to extraction; the contralateral tooth served as the control tooth.

Severity of nursing-bottle syndrome and feeding patterns in Kuwait.

On the basis of extensive clinical experience, a classification scheme for nursing-bottle syndrome (NBS) has been empirically constructed to reflect the progression and severity of the disease. Patients who do not have NBS are assigned a score of zero. Patients with NBS are given a score of 1 if they have caries on the facial or lingual surface of at least one of the primary maxillary incisors and optionally the primary maxillary first molars, a 2 if the buccal surface of one or both of the primary mandibular first molars are also involved, or a 3 if specific multiple surfaces are involved.

Clinical profiles of individuals with and without root surface caries.

As part of a collaborative multidisciplinary investigation of root surface caries (RSC), 273 subjects (median age = 57) were clinically evaluated for coronal caries, debris, calculus, gingivitis, periodontal pocketing, recession, abrasion, as well as RSC. The entire study group was divided into three subgroups: (1) subjects whose exposed root surface were without lesions or restorations (non-diseased individuals, n = 43); (2) subjects whose exposed root surfaces had one or more lesions and may or may not have had restorations (diseased individuals, n = 110); (3) subjects with one or more restorations but no lesions, since it was not known whether these restorations were preceded by RSC or abrasion the disease status of these individuals was unclear (n = 120). A comparison of Subgroup 1 (unequivocally non-diseased) and Subgroup 2 (unequivocally diseased) revealed that subjects without RSC had more teeth, less coronal caries, less recession, less debris, less calculus, less gingivitis, and more abrasion.

Methodological issues relative to the quantification of root surface caries.

The purpose of this study was to assess the effect upon the quantification of root surface caries (RSC) of (1) the separation of the disease into its discrete clinical phases, (2) the confounding caused by the presence of restored abraded surfaces, and (3) the decision rule formulated for dealing with lesions and restorations which involve both crown and root. It was found that the apparent prevalence of RSC varied widely depending upon arbitrary decisions as to what stages of the disease were included in the measurement scheme. The addition of restorations (confined to the root) greatly enlarged the various disease measures, but probably also introduced some degree of error since there are several indications from the data and the clinical patterns of affected surfaces which suggest that some of the restored surfaces were formerly abraded rather than carious.

The reliability of the iodide permeability test applied to the natural dentition.

The purpose of this study was to assess the reliability of the iodide permeability test when applied to the human dentition. Twenty-two subjects were seen once a week for three weeks. At each visit, consecutive iodide permeability measurements were obtained: four from the right central incisor and four from the left.