Subcutaneous administration of levothyroxine: a novel approach to refractory hypothyroidism - A review and a case report.

Treatment-refractory hypothyroidism is a common clinical finding. Substantial causes include poor compliance and intake failure as well as gastrointestinal diseases, such as inflammatory bowel disease and short bowel syndromes. Increasing oral dosage of levothyroxine (LT4) is not always effective. Therefore, alternative routes of administration are necessary. In this report, we evaluate alternative treatment modalities for refractory hypothyroidism and present a 28-year-old woman with intestinal drug malabsorption successfully treated by subcutaneous LT4 administration. In this patient, a parenteral form of LT4, 500 µg/5 ml, was administered subcutaneously in a split dosage regimen. Blood hormone levels returned to normal within a few days and remained stable over an 8-month follow-up period.

Subcutaneous administration of levothyroxine: a novel approach to refractory hypothyroidism - A review and a case report

SUMMARY Treatment-refractory hypothyroidism is a common clinical finding. Substantial causes include poor compliance and intake failure as well as gastrointestinal diseases, such as inflammatory bowel disease and short bowel syndromes. Increasing oral dosage of levothyroxine (LT4) is not always effective. Therefore, alternative routes of administration are necessary. In this report, we evaluate alternative treatment modalities for refractory hypothyroidism and present a 28-year-old woman with intestinal drug malabsorption successfully treated by subcutaneous LT4 administration. In this patient, a parenteral form of LT4, 500 μg/5 ml, was administered subcutaneously in a split dosage regimen. Blood hormone levels returned to normal within a few days and remained stable over an 8-month follow-up period.

Why is Amazonia a 'source' of biodiversity? Climate-mediated dispersal and synchronous speciation across the Andes in an avian group (Tityrinae).

Amazonia is a 'source' of biodiversity for other Neotropical ecosystems, but which conditions trigger in situ speciation and emigration is contentious. Three hypotheses for how communities have assembled include (1) a stochastic model wherein chance dispersal events lead to gradual emigration and species accumulation, (2) diversity-dependence wherein successful dispersal events decline through time due to ecological limits, and (3) barrier displacement wherein environmental change facilitates dispersal to other biomes via transient habitat corridors. We sequenced thousands of molecular markers for the Neotropical Tityrinae (Aves) and applied a novel filtering protocol to identify loci with high utility for dated phylogenomics. We used these loci to estimate divergence times and model Tityrinae's evolutionary history. We detected a prominent role for speciation driven by barriers including synchronous speciation across the Andes and found that dispersal increased toward the present. Because diversification was continuous but dispersal was non-random over time, we show that barrier displacement better explains Tityrinae's history than stochasticity or diversity-dependence. We propose that Amazonia is a source of biodiversity because (1) it is a relic of a biome that was once more extensive, (2) environmentally mediated corridors facilitated emigration and (3) constant diversification is attributed to a spatially heterogeneous landscape that is perpetually dynamic through time.

Phylogenomics and species delimitation of a complex radiation of Neotropical suboscine birds (Pachyramphus).

Phylogeographic studies within the Neotropics continue to uncover hidden diversity, the extent of which remains poorly known. In birds, molecular studies are producing evidence that species-level diversity is substantially underestimated. Many avian taxa comprise large complexes of subspecies that often represent species-level taxa by various criteria. One such group of Neotropical suboscine birds, the becards (Pachyramphus), ranges from Argentina through northern Mexico. Their taxonomic limits have been complex and controversial as the genus has bounced around a number of suboscine families. Additionally, the phylogenetic relationships within Pachyramphus are unresolved due to insufficient sampling of taxa and populations across species' ranges. We used target capture of ultraconserved elements for 62 individuals representing 42 taxa, and sequenced two mitochondrial genes and two nuclear introns covering 265 individuals of 51 taxa, including all recognized species, resulting in the most densely and completely sampled phylogenetic hypothesis for Pachyramphus to date. We delimited species using a traditional taxonomic approach and then tested them under a Bayesian multi-species coalescent framework. In doing so, we provide evidence for multiple young, previously undetected evolutionary lineages within Pachyramphus. Deep, well-supported branches and a high number of intraspecific lineages across the tree suggest that at least 50% of species diversity may be unrecognized.