Social and biological early life influences on the prevalence of open bite in Brazilian 6-year-olds

OBJECTIVE: Little is known about the effects of social and biological risk factors for open bite on the primary dentition. The aim of this study was to assess the early-life risk factors affecting anterior open bite. METHODS: A cross-sectional study using a birth cohort was carried out in Pelotas, Brazil. A sample of 400, 6-year-old children was employed. The Foster and Hamilton criteria were used to classify open bite. Data concerning social conditions, and perinatal and childhood health and behaviour were obtained from birth to 12 months of age and during the fifth year of the children's lives. Unconditional bivariate and multiple logistic regression analysis were performed. RESULTS: The prevalence of anterior open bite was 46.3%. Risk factors included: a maternal age of between 30 and 39 years, as compared with children whose mothers were younger; breast-feeding for < 9 months; dental caries experience; pacifier sucking between 12 months and 5 years, as compared to no sucking or a shorter duration of sucking; and the presence of finger-sucking at 6 years of age. CONCLUSION: Open bite in the primary dentition was associated with older mothers, early weaning, dental caries occurrence, long-term use of a pacifier and finger-sucking at 6 years of age. These findings support the common risk approach for intervention to prevent open bite in the primary dentition.     

Population Pharmacokinetic/ Pharmacodynamic Modelling of Auditory‐Evoked Event‐Related Potentials with Lorazepam

Event‐related potentials (ERPs) are commonly used in Neuroscience research, particularly the P3 waveform because it is associated with cognitive brain functions and is easily elicited by auditory or sensory inputs. ERPs are affected by drugs such as lorazepam, which increase the latency and decrease the amplitude of the P3 wave. In this study, auditory‐evoked ERPs were generated in 13 older healthy volunteers using an oddball tone paradigm, after administration of single 0.5 and 2 mg doses of lorazepam. Population pharmacokinetics (PK)/pharmacodynamics (PD) models were developed using nonlinear mixed‐effects methods in order to assess the effect of lorazepam on the latency and amplitude of the P3 waveforms. The PK/PD models showed that doses of 0.3 mg of lorazepam achieved approximately half of the maximum effect on the latency of the P3 waveform. For P3 amplitude, half the maximum effect was achieved with a dose of 1.2 mg of lorazepam. The PK/PD models also predicted an efficacious dose range of lorazepam, which was close to the recommended therapeutic range. The use of longitudinal P3 latency data allowed better predictions of the lorazepam efficacious dose range than P3 amplitude or aggregate exposure–response data, suggesting that latency could be a more sensitive parameter for drugs with similar mechanisms of action as lorazepam and that time course rather than single time‐point ERP data should be collected. Overall, the results suggest that P3 ERP waveforms could be used as potential non‐specific biomarkers for functional target engagement for drugs with brain activity, and PK/PD models can aid trial design and choice of doses for development of new drugs with ERP activity.     

Analgesic and antiinflammatory activities of the ethyl acetate fraction of Bidens pilosa (Asteraceae)

Bidens pilosa is an Asteraceae widely used in traditional medicine for the treatment of various ailments including pain and inflammation. The present work was undertaken to assess the analgesic and antiinflammatory properties of the ethyl acetate fraction of methylene chloride/methanol (1:1) extract of leaves of Bidens pilosa at the gradual doses of 50, 100 and 200 mg/kg in mice and rats, respectively. The analgesic properties of Bidens pilosa were investigated using the acetic acid writhing, hot plate, capsaicin and formalin-induced pain models. This was followed by a study of the antiinflammatory properties using carrageenan, dextran, histamine and serotonin to induce acute inflammation in rat hind paw. The extract provided a significant (p < 0.01) reduction in pain induced by all four models of nociception. It also presented significant (p < 0.05) antiinflammatory activity in all four models of acute inflammation. These results show that the ethyl acetate fraction of methylene chloride/methanol (1:1) of Bidens pilosa has both analgesic and antiinflammatory properties. The qualitative analysis of the fraction by the high-performance liquid chromatography (HPLC) fingerprint revealed the presence of two flavonoids, namely quercetin and iso-okanin, known to have antiinflammatory and antinociceptive properties, which could be responsible for the analgesic and antiinflammatory effects observed.     

Peak Cough Flow Fails to Detect Upper Airway Collapse During Negative Pressure Titration for Cough-Assist

ObjectiveTo study the ability of peak cough flow (PCF) and effective cough volume, defined as the volume exsufflated >3 L/s, to detect upper airway collapse during mechanical insufflation-exsufflation (MI-E) titration in neuromuscular patients.DesignProspective observational study.SettingRehabilitation hospital.ParticipantsPatients (N=27) with neuromuscular disease causing significant impairment of chest wall and/or diaphragmatic movement.InterventionsThe lowest insufflation pressure producing the highest inspiratory capacity was used. Exsufflation pressure was decreased from ?20 cm H₂O to ?60/?70 cm H₂O, in 10-cm H₂O decrements, until upper airway collapse was detected using the reference standard of flow-volume curve analysis (after PCF, abrupt flattening or flow decrease vs previous less negative exsufflation pressure).Main Outcome MeasuresPCF and effective cough volume profiles during expiration with MI-E.ResultsUpper airway collapse occurred in 10 patients during titration. Effective cough volume increased with decreasing expiratory pressure then decreased upon upper airway collapse occurrence. PCF continued to increase after upper airway collapse occurrence. In 5 other patients, upper airway collapse occurred at the initial ?20 cm H₂O exsufflation pressure, and during titration, PCF increased and effective cough volume remained unchanged at <200 mL. PCF had 0% sensitivity for upper airway collapse, whereas effective cough volume had 100% sensitivity and specificity.ConclusionOf 27 patients, 15 experienced upper airway collapse during MI-E titration. Upper airway collapse was associated with an effective cough volume decrease or plateau and with increasing PCF. Accordingly, effective cough volume, but not PCF, can detect upper airway collapse.     

High-order mutants reveal an essential requirement for peroxidases but not laccases in Casparian strip lignification

Lignin has enabled plants to colonize land, grow tall, transport water within their bodies, and protect themselves against various stresses. Consequently, this polyphenolic polymer, impregnating cellulosic plant cell walls, is the second most abundant polymer on Earth. Yet, despite its great physiological, ecological, and economical importance, our knowledge of lignin biosynthesis in vivo, especially the polymerization steps within the cell wall, remains vague—specifically, the respective roles of the two polymerizing enzymes classes, laccases and peroxidases. One reason for this lies in the very high numbers of laccases and peroxidases encoded by 17 and 73 homologous genes, respectively, in Arabidopsis. Here, we have focused on a specific lignin structure, the ring-like Casparian strips (CSs) within the root endodermis. By reducing candidate numbers using cellular resolution expression and localization data and by boosting stacking of mutants using CRISPR-Cas9, we mutated the majority of laccases in Arabidopsis in a nonuple mutant—essentially abolishing laccases with detectable endodermal expression. Yet, we were unable to detect even slight defects in CS formation. By contrast, we were able to induce a complete absence of CS formation in a quintuple peroxidase mutant. Our findings are in stark contrast to the strong requirement of xylem vessels for laccase action and indicate that lignin in different cell types can be polymerized in very distinct ways. We speculate that cells lignify differently depending on whether lignin is localized or ubiquitous and whether cells stay alive during and after lignification, as well as the composition of the cell wall.

Casparian strips (CSs) are highly conserved structures that are a defining feature of the root endodermis in higher plants. That CSs are of a lignin-like nature had been proposed repeatedly since their discovery in the 19th century and was firmly established by modern histological and genetic analyses in the model plant Arabidopsis (1, 2). CSs are strictly localized cell wall impregnations, forming as longitudinal, centrally located belts between endodermal cells. Their highly coordinated and simultaneous appearance in endodermal neighbors leads to the fusion of these belts into a supracellular structure that takes the appearance of a delicate network, due to the very thin primary cell walls of young endodermal cell (100 to 200 nm in width). Using lignin stains, this fine network can be easily overlooked, next to the much more pronounced lignification occurring at the same time in the thick secondary cell walls of protoxylem vessels, only two cell layers below within the vasculature. The CSs therefore represent only a minor fraction of the overall lignin content of a root and are always found in close association to the xylem, making it very difficult to use the classical chemical methods of lignin analysis that are central to the field. Yet, CSs are very attractive for cell biological and genetic analyses for a number of reasons. The endodermis can be observed in very young, 5-d-old seedlings, and it is a relatively peripheral, large cell type that is more easily observed than cell types in the vasculature. Moreover, its highly predictable and restricted lignification allows for meaningful spatial correlations between protein localization and lignin deposition. Finally, the endodermis stays alive during and after the entire process of lignification (3). Using the endodermis as a model, we were able to establish a strong requirement for reactive oxygen species (ROS) production in CS lignification. Knockouts of a single NADPH oxidase, respiratory burst oxidase homolog F (RBOHF), led to a near absence of lignification in the endodermis, as did inhibitor treatments interfering with ROS production or accumulation (2). Intriguingly, RBOHF specifically accumulates at the site of CS formation, which is initiated by the accumulation of CASPARIAN STRIP MEMBRANE DOMAIN PROTEINS (CASPs), small transmembrane scaffold proteins that are thought to recruit RBOHF and other proteins to their site of action. Another class of proteins that appear to be localized by CASPs is type III peroxidases (PER). Among those, PER64 showed an especially strict colocalization with CASP1. Indeed, transfer DNA (T-DNA) insertion- and artificial microRNA (amiRNA)-driven knockout/knockdown of multiple endodermis-expressed and CS-localized peroxidases led to a delay of barrier formation (2), although the severity and nature of lignin defects were not assessed at that time. These findings led to a model whereby CASPs are acting to bring together NADPH oxidase and peroxidase, effectively allowing channel-localized ROS production toward peroxidases, thus ensuring localized and efficient lignification (2). Clearly, localized presence of RBOHF and peroxidases is sufficient for localizing lignification since complementation of monolignol-deficient plants with large amounts of external monolignols did not affect localization of CS formation (1). More recently, we showed that a dedicated receptor pathway in the endodermis can detect defects in the CS diffusion barrier and initiate compensatory, ectopic lignification in cell corners, both by enhancing ROS production from RBOHF and RBOHD and inducing expression of genes, including additional peroxidases and laccases (LAC) (4–6). Our findings demonstrating a strong requirement for ROS production and a partial genetic requirement for peroxidases was in contrast with the finding that LACCASES (LACs) are necessary for lignification of xylem vessels, fibers, and other cell types. LACs are glycosylated, multicopper enzymes that catalyze the oxidation of various phenolic substrates using O₂ as final electron acceptor, not requiring H₂O₂ (7, 8). LAC15 was found to express in seed coats, its loss-of-function mutant displaying a 30% reduction of lignin in seeds (9, 10). LAC4, also called IRREGULAR XYLEM 12 (11), and LAC17 are expressed in vessels and xylary fibers in the stem (12). LAC4 localizes to secondary cell wall domains of proto- and metaxylem vessels, as well as vessels, xylary, and interfascicular fibers of inflorescence stems (12–15). Mutant lines of lac4 and lac4 lac17 have collapsed xylem vessels and reduced lignin content in total stem biomass (12). The reduction in lignin content of the double mutant was further enhanced in the presence of an lac11 mutant, which showed severe developmental defects and stopped growing after developing the two first pair of leaves (16). Finally, LAC15 and LAC7 are expressed in lignifying cells in the context of floral organ abscission, although it was not demonstrated whether mutations of both LACs affected lignin deposition in this context (17). More recently, LAC2 was found to negatively regulate overlignification in the root vasculature upon phosphate and water deficiency. Nevertheless, the exact role of LAC2 in such context was not determined (18).Yet, numerous studies have also provided evidence for participation of PERs in lignification outside of the endodermis. In the Arabidopsis stem xylem vessels, mutations of PERs partially impact lignification (19, 20). It was proposed that both enzymes act sequentially in the lignin polymerization of a same cell type, although it has not been excluded that they individually lignify different cell types (8, 15, 21). Cell cultures of the gymnosperm Norway spruce release lignin polymers into the growth medium (22). Scavenging of H₂O₂ prevents production of this extracellular lignin, and phenolic profiling of the culture media of scavenger-treated cell cultures revealed the accumulation of specific oligolignols (21). This led the authors to propose that H₂O₂-independent enzymes, such as laccases, mediate formation of oligolignols, while peroxidases would be required for further polymerization. However, the authors could not exclude the possibility that in their treatment to scavenge H₂O₂, a residual PERs activity was present (21). Unfortunately, participation of PER in lignification in planta has often been inferred from the use of inhibitors of PERs or H₂O₂ production (2, 23), while genetic evidence could reveal only weak, partial effects on lignification, allowing for the possibility that peroxidases are only peripheral actors of lignification in planta.In addition to PERs, data of cell type-specific gene expression have revealed that LACs are expressed in the endodermis (24–27). Considering the evidence on the role of LACs in lignification, we took advantage of the experimental setup offered by the endodermis to conduct a genetic analysis of LACs in order to determine whether they contribute to lignin polymerization in the CS.In this work, we set out to determine whether one given lignin structure in a cell requires either laccases or peroxidases exclusively or whether its formation requires a combination of both enzyme classes. Using the endodermal CS as a model, we demonstrate that a number of laccases show specific expression in the endodermis and localization to the CS, yet generation of a nonuple mutant, mutating the vast majority of laccases with detectable endodermal expression, had no discernable effect on CS lignification or formation of the endodermal barrier. By contrast, generating a quintuple mutant of endodermis-enriched peroxidases led to a complete absence of CS lignification. Abrogating the compensatory lignification by the SCHENGEN pathway even led to a complete absence of any lignification in young endodermal cells.Based on this, it is most parsimonious to conclude that, despite their strong presence, laccases are fully replaceable for lignification of CS, while peroxidases are absolutely required.     

Impact of front line relative dose intensity for methotrexate and comorbidities in immunocompetent elderly patients with primary central nervous system lymphoma

Primary central nervous system lymphomas (PCNSL) are non-Hodgkin lymphomas strictly localized to the CNS, occurring mainly in elderly patients with comorbidities. Current treatment in fit patients relies on high-dose methotrexate and high-dose cytarabine. The aim of this study was to evaluate the efficacy and feasibility of this treatment in elderly patients and to assess potential prognostic factors associated with survival. We conducted a retrospective study in two centers between January 2008 and September 2015 including 35 elderly immunocompetent patients who received first-line treatment with high-dose methotrexate. With a median follow-up of 19.8 months (range: 1.7–73.4 months), median overall survival (OS) was 39.5 months (95% confidence interval (95% CI): 18.3–60.7) and median progression-free survival (PFS) was 25.8 months (95% CI: 5.2–46.4). In univariate analysis, administration of high-dose cytarabine and achieving a relative dose intensity for methotrexate >?75% were associated with increased OS (p?=?0.006 and p?=?0.003, respectively) and PFS (p?=?0.003 and p?=?0.04, respectively) whereas comorbidities, defined by a CIRS-G score ≥?8, were associated with decreased OS and PFS (p?=?0.02 and p?=?0.04, respectively). A high MSKCC score was associated with decreased OS (p?=?0.02). In multivariate analysis, administration of high-dose cytarabine was associated with increased OS and PFS (p?=?0.02 and p?=?0.007, respectively). Comorbidities and relative dose intensity for methotrexate are important for the prognosis of elderly patients with PCNSL. These results must be confirmed in prospective trials.