The use of environmental DNA (eDNA) to monitor rare and elusive species has great potential for conservation biology. Traditional surveying methods can be time-consuming, labour-intensive, subject to ...error or can be invasive and potentially damaging to habitat. The Trinidad golden treefrog (Phytotriades auratus) is one such species that would benefit from such an approach. This species inhabits the giant bromeliad (Glomeropitcairnia erectiflora) on two peaks on the Caribbean island of Trinidad. Traditional survey methods for this species have required the destruction of the giant bromeliad, which is the only known habitat of this frog. Here we described the development of an eDNA PCR-based assay that uses water drawn from the water-filled phytotelmata of the giant bromeliad along with the use of a synthetic DNA positive control that can be easily amplified in the bacterium Escherichia coli. The assay can detect to a DNA concentration of 1.4ng. Sampling of 142 bromeliads using this method revealed 9% were positive for P. auratus DNA. These data suggest that eDNA methods also have great potential for revealing the presence of elusive species in arboreal habitats.
Recent reviews on sexual dichromatism in frogs included Mannophryne trinitatis as the only example they could find of dynamic dichromatism (males turn black when calling) within the family ...Aromobatidae and found no example of ontogenetic dichromatism in this group. We demonstrate ontogenetic dichromatism in M. trinitatis by rearing post-metamorphic froglets to near maturity: the throats of all individuals started as grey coloured; at around seven weeks, the throat became pale yellow in some, and more strongly yellow as development proceeded; the throats of adults are grey in males and variably bright yellow in females, backed by a dark collar. We demonstrated the degree of throat colour variability by analysing a large sample of females. The red: green (R:G) ratio ranged from ~1.1 to 1.4, reflecting variation from yellow to yellow/orange, and there was also variation in the tone and width of the dark collar, and in the extent to which the yellow colouration occurred posterior to the collar. Female M. trinitatis are known to be territorial in behaviour. We show a positive relationship between throat colour (R:G ratio) and escape performance, as a proxy for quality. Our field observations on Tobago's M. olmonae showed variability in female throat colour and confirmed that males in this species also turn black when calling. Our literature review of the 20 Mannophryne species so far named showed that all females have yellow throats with dark collars, and that male colour change to black when calling has been reported in eight species; in the remaining 12 species, descriptions of males calling are usually lacking so far. We predict that both dynamic and ontogenetic sexual dichromatism are universal in this genus and provide discussion of the ecological role of dichromatism in this genus of predominantly diurnal, non-toxic frogs, with strong paternal care of offspring.
Abstract Wildlife diseases are contributing to the current Earth’s sixth mass extinction; one disease, chytridiomycosis, has caused mass amphibian die-offs. While global spread of a hypervirulent ...lineage of the fungus Batrachochytrium dendrobatidis ( Bd GPL) causes unprecedented loss of vertebrate diversity by decimating amphibian populations, its impact on amphibian communities is highly variable across regions. Here, we combine field data with in vitro and in vivo trials that demonstrate the presence of a markedly diverse variety of low virulence isolates of Bd GPL in northern European amphibian communities. Pre-exposure to some of these low virulence isolates protects against disease following subsequent exposure to highly virulent Bd GPL in midwife toads ( Alytes obstetricans ) and alters infection dynamics of its sister species B. salamandrivorans in newts ( Triturus marmoratus ), but not in salamanders ( Salamandra salamandra ). The key role of pathogen virulence in the complex host-pathogen-environment interaction supports efforts to limit pathogen pollution in a globalized world.
Abstract
Background
Patients requiring optimization of therapy for suboptimal response and/or targeting more robust outcomes may eventually reach high serum levels. Data evaluating the relationship ...between infliximab concentration and toxicity are limited. The aim of this study was to evaluate the frequency of adverse events (AEs) in inflammatory bowel disease (IBD) patients with infliximab higher-range (HR) and lower-range (LR) trough levels.
Methods
We performed a retrospective analysis of 180 patients with at least 1 measurement of serum infliximab from 2012 to 2016. The cohort was divided according to an infliximab level cutoff of 15 µg/mL (HR and LR). The primary outcome was frequency of AEs, including infections, dermatological manifestations, and infusion reactions, between the 2 groups. The secondary outcomes included frequencies of all AEs (dermatological manifestations, infusion reactions, autoimmune reactions, and opportunistic and serious infections) in both groups. AEs were also compared against observed infliximab level quartiles using logistic regression analysis.
Results
A total of 53 AEs in 47 patients were reported in the overall cohort. In the LR group, there were 36 AEs recorded in 30 patients, whereas in the HR group, 17 AEs were experienced by 17 patients. Patients with HR levels did not have a higher prevalence of infections in comparison with patients with LR levels (12.2% vs 18.8%; P = 0.3). Stratification of infliximab levels by quartiles showed a comparable frequency of infection.
Conclusions
Our findings indicate that higher infliximab serum concentrations are not associated with a higher frequency of infections.
Background and Aim
Crohn's disease (CD) patients who previously failed anti‐tumor necrosis factor (TNF) therapy are at higher risk of treatment failure with subsequent biologics. This study aims to ...determine the effectiveness and safety of higher maintenance dose regimens of adalimumab compared with standard doses in CD patients who failed anti‐TNF.
Methods
In this retrospective observational study, CD patients who failed anti‐TNF and received adalimumab were categorized according to their post‐induction maintenance regimen; 40 mg subcutaneous (sc) weekly or 80 mg sc every other week were defined as a high‐dose (HD) maintenance regimen, and 40 mg sc every other week was defined as a standard‐dose (SD) maintenance regimen. The primary outcome was time to treatment failure. Cox proportional hazards regression was used to adjust for confounders. Sensitivity analysis was conducted using propensity scores to create a cohort of matched participants with similar distribution of baseline covariates.
Results
Forty patients started on HD regimens following induction, and 77 patients received the SD regimen. The median time to failure in the HD group was 6.6 years (interquartile range IQR 4.0–9.6) and 3.0 years (IQR 0.9–9.4) in the SD group (log‐rank test P = 0.006). Patients on HD adalimumab had a lower hazard rate of treatment failure (hazard ratio: 0.27; 95% confidence interval 0.12, 0.62; P = 0.002) compared with SD patients. No difference in adverse events was identified between groups (30% vs 31.2%, P = 1.0). Results were similar in the propensity score‐matched cohort.
Conclusions
High‐dose maintenance regimens were associated with longer time‐to‐failure as compared with SD regimens in CD patient who failed anti‐TNF.
Abstract
Introduction
Golimumab is approved as a therapy for ulcerative colitis (UC) patients. Recent data also demonstrate efficacy in Crohn’s disease (CD); however, little is known about target ...drug levels to achieve endoscopic remission.
Methods
We performed a retrospective analysis of IBD patients on maintenance golimumab. Median trough levels were compared using Kruskal-Wallis test, and logistic regression was used to construct a probabilistic model to determine sensitivity and specificity of levels predicting mucosal healing.
Results
Fifty-eight patients on maintenance golimumab were included (n = 39 CD, n = 19 UC/IBD-unclassified IBDU). Forty percent (n = 23) were cotreated with an immunomodulator, 95% (n = 55) of patients were anti-TNF experienced, and 15.5% (n = 9) had 3 or more prior biologic therapies. Forty-four percent of patients achieved mucosal healing with endoscopic response in a further 26% of patients. Clinical remission was recorded in 41% of patients, and 82% had clinical response. Patients were treated with doses generally higher than the approved maintenance dose. In CD patients, median golimumab trough levels were higher in patients with mucosal healing (8.8 μg/mL vs 5.08 μg/mL, P = 0.03). After calculation of a receiver operating characteristic (ROC) curve for mucosal healing vs nonresponse, a trough level >8 μg/mL was associated with mucosal healing, with 67% sensitivity, 88% specificity, and a likelihood ratio of 3:4.
Conclusion
Treatment with golimumab was associated with mucosal healing in 44% of all IBD patients. Higher golimumab levels were associated with mucosal healing in CD. These findings support the need for prospective studies to determine target golimumab levels in IBD, which may impact current clinical practices in relation to selection of maintenance dosing.
Recent data have outlined the potential of golimumab to achieve mucosal healing in Crohn’s disease and ulcerative colitis, but drug monitoring targets are lacking. We have identified golimumab trough levels associated with mucosal healing in a largely anti-TNF experienced patient population.
Trinidad and Tobago are home to three endemic species in the anuran genus Pristimantis, of which two (Pristimantis charlottevillensis and Pristimantis turpinorum) occur in Tobago alone and the third ...(Pristimantis urichi) is present on both islands. Earlier, the IUCN assessed the conservation status of these species as: P. urichi, Endangered (EN); P. charlottevillensis, Least Concern (LC); P. turpinorum, Vulnerable (VU). However, these assessments were based on very little field‐based evidence. Here, we present survey results which contributed to reassessments as LC, VU and Data Deficient for these three species, respectively. Despite the close proximity of Trinidad to northern Venezuela, the islands do not share any Pristimantis species with the mainland, which holds a rich endemicity of Pristimantis regionally. In this study, we used genetic sequencing from several island populations and compared them to northern Venezuelan endemics to assess genetic divergence for the first time. The time tree analyses found that only the northern Tobago species P. turpinorum is closely related to mainland Pristimantis, with a genetic split dating to the Late Miocene, suggesting a vicariant event of mainland and island species. Pristimantis urichi, although identical between the two islands, remains highly divergent from the mainland species. Similar results were found for P. charlottevillensis. In addition, there was a high level of divergence between P. urichi and P. charlottevillensis. These findings indicate different island colonization events by different lineages. Sequencing other Venezuelan species remains pivotal to unravel the complexity of the colonization episodes in the region, likely influenced by the changing topography and multiple connection and isolation episodes of the islands by eustatic sea‐level changes.
Surveys made from 2012 to 2020 for the three Pristimantis species endemic to Trinidad and Tobago, assessment of their conservation status, distribution, and genetic affinities.
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