The role of tooth enamel mechanical properties in primate dietary adaptation

Primate teeth adapt to the physical properties of foods in a variety of ways including changes in occlusal morphology, enamel thickness, and overall size. We conducted a comparative study of extant primates to examine whether their teeth also adapt to foods through variation in the mechanical properties of the enamel. Nanoindentation techniques were used to map profiles of elastic modulus and hardness across tooth sections from the enamel-dentin junction to the outer enamel surface in a broad sample of primates including apes, Old World monkeys, New World monkeys, and lemurs. The measured data profiles feature considerable overlap among species, indicating a high degree of commonality in mechanical properties. These results suggest that differences in the load-bearing capacity of primate molar teeth are more a function of morphology-particularly tooth size and enamel thickness-than of underlying mechanical properties.     

Fatal toxoplasmosis in a southern muriqui (Brachyteles arachnoides) from São Paulo state,Brazil: Pathological,immunohistochemical, and molecular characterization

We report the pathological, immunohistochemical, and molecular features of fatal acute systemic toxoplasmosis in an adult, female, free‐living southern muriqui (Brachyteles arachnoides) from São Paulo state, Brazil. PCR‐RFLP genotyping analysis identified the #21 genotype of Toxoplasma gondii. This represents the first report of acute toxoplasmosis involving this genotype in humans and animals.     

Frequency of antibiotic resistance in <Emphasis Type="Italic">Helicobacter pylori</Emphasis> strains isolated from the northern population of Iran

The purpose of this study was to evaluate the primary resistance rates of recent clinical Helicobacter pylori isolates to the most commonly used antibiotics in Iran. Two hundreds and ten patients presenting with gastric maladies between January and July of 2009 were enrolled in this study. Endoscopy was performed, and biopsy specimens were collected from each patient for subsequent bacterial culture of H. pylori. Single colony isolates from each patient were then used for antimicrobial susceptibility testing. The disk diffusion method was used to determine susceptibility patterns. One hundred and ninety-seven of the patients were H. pylori positive (93.8%). The rates of resistance to tetracycline, amoxicillin, ciprofloxacin, metronidazole, clarithromycin, and furizoladone were 37.1%, 23.9%, 34.5%, 65.5%, 45.2%, and 61.4%, respectively. A significant association between amoxicillin resistance and disease state (P<0.05) was identified. Furthermore, some double, triple, quadruple, and quintuple combinations of antibiotic resistance were found to be associated with disease state. This study evaluated the prevalence of H. pylori resistance to the most commonly prescribed antibiotics used in Iran and showed that resistance rates were generally higher than previously reported. This data adds to the growing body of evidence that suggests there is increasing antibiotic resistance among H. pylori isolates, which likely is responsible for the decreasing efficacy of anti-H. pylori therapy at the local and global level. Hence, there is a need for continued monitoring of resistance patterns, especially at the local level, and for incorporation of that information into treatment regimens for H. pylori infections.     

An improved heuristic for haplotype inference

Haplotypes include essential SNP information used for a variety of purposes such as investigating potential links between certain diseases and genetic variations. Given a set of genotypes, the haplotype inference problem based on pure parsimony is the problem of finding a minimum set of haplotypes that explains all the given genotypes. The problem is especially important because, while it is fairly inexpensive to obtain genotypes, other approaches to obtaining haplotypes are significantly expensive. There are two types of methods proposed for the problem, namely exact and inexact methods. Existing exact methods guarantee obtaining purely parsimonious solutions but have exponential time-complexities and are not practical for large number or length of genotypes. However, inexact methods are relatively fast but do not always obtain optimum solutions. In this paper, an improved heuristic is proposed, based on which new inexact and exact methods are provided. Experimental results indicate that the proposed methods replace the state-of-the-art inexact and exact methods for the problem.     

Transplantation of stem cells from human exfoliated deciduous teeth for bone regeneration in the dog mandibular defect

AIM: To investigate the effect of stem cells from human exfoliated deciduous teeth(SHED) transplanted for bone regeneration in the dog mandibular defect.METHODS: In this prospective comparative study, SHEDs had been isolated 5 years ago from human exfoliated deciduous teeth. The undifferentiated stem cells were seeded into mandibular bone through-andthrough defects of 4 dogs. Similar defects in control group were filled with cell-free collagen scaffold. After 12 wk, biopsies were taken and morphometric analysis was performed. The percentage of new bone formation and foreign body reaction were measured in each case. The data were subject to statistical analysis using the Mann-Whitney U and Kruskalwalis statistical tests. Differences at P 0.05 was considered as significant level.RESULTS: There were no significant differences between control and SHED-seeded groups in connective tissue(P = 0.248), woven bone(P = 0.248) and compact bone(P = 0.082). There were not any side effects in transplanted SHED group such as teratoma or malignancy and abnormalities in this period.CONCLUSION: SHEDs which had been isolated and characterized 5 years ago and stored with cryopreservation banking were capable of proliferation and osteogenesis after 5 years, and no immune response was observed after three months of seeded SHEDs.     

SARS-CoV-2 outbreak in a tri-national urban area is dominated by a B.1 lineage variant linked to a mass gathering event

The first case of SARS-CoV-2 in Basel, Switzerland was detected on February 26^th 2020. We present a phylogenetic study to explore viral introduction and evolution during the exponential early phase of the local COVID-19 outbreak from February 26^th until March 23^rd. We sequenced SARS-CoV-2 naso-oropharyngeal swabs from 746 positive tests that were performed at the University Hospital Basel during the study period. We successfully generated 468 high quality genomes from unique patients and called variants with our COVID-19 Pipeline (COVGAP), and analysed viral genetic diversity using PANGOLIN taxonomic lineages. To identify introduction and dissemination events we incorporated global SARS-CoV-2 genomes and inferred a time-calibrated phylogeny. Epidemiological data from patient questionnaires was used to facilitate the interpretation of phylogenetic observations. The early outbreak in Basel was dominated by lineage B.1 (83·6%), detected first on March 2^nd, although the first sample identified belonged to B.1.1. Within B.1, 68·2% of our samples fall within a clade defined by the SNP C15324T (‘Basel cluster’), including 157 identical sequences at the root of the ‘Basel cluster’, some of which we can specifically trace to regional spreading events. We infer the origin of B.1-C15324T to mid-February in our tri-national region. The other genomes map broadly over the global phylogenetic tree, showing several introduction events from and/or dissemination to other regions of the world via travellers. Family transmissions can also be traced in our data. A single lineage variant dominated the outbreak in the Basel area while other lineages, such as the first (B.1.1), did not propagate. A mass gathering event was the predominant initial source of cases, with travel returners and family transmissions to a lesser extent. We highlight the importance of adding specific questions to epidemiological questionnaires, to obtain data on attendance of large gatherings and their locations, as well as travel history, to effectively identify routes of transmissions in up-coming outbreaks. This phylogenetic analysis in concert with epidemiological and contact tracing data, allows connection and interpretation of events, and can inform public health interventions.Trial Registration: ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT04351503","term_id":"NCT04351503"}}NCT04351503.