The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)

The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here

Effect of Anti-Tuberculous Therapy on Uveitis Associated with Latent Tuberculosis

PURPOSE: To describe the clinical features of patients with uveitis associated with latent tuberculosis (TB) and examine the effect of anti-TB treatment (ATT) on uveitis outcome. DESIGN: Retrospective cohort study METHODS: 199 eyes of 129 patients diagnosed with uveitis associated with latent TB were evaluated for recurrence of disease following treatment. Eighty nine of the patients (69%) received ATT and information was gathered retrospectively regarding clinical outcome, vision and treatment. Outcome measures included: best corrected visual acuity (BCVA) and rate of disease recurrence. RESULTS: This study included eighty-nine patients (69%) received ATT and 40 patients who did not. The uveitis was treated with local and systemic anti-inflammatory and immunosuppressive therapy in all patients. The mean change in BCVA following treatment was 4.5±1.4 letters over the follow-up period, with no difference between eyes of patients receiving ATT and those who did not. Sixty-eight eyes (34.9%) had a recurrence of uveitis (0.64±0.08 recurrences per-year), with eyes of patients receiving ATT less likely to develop a recurrence compared to those not receiving ATT (29.5% vs. 48.2%, OR 0.47, 95% CI 0.29-0.77, p=0.003). Eyes treated with ATT recurred at an estimated median of 120 months compared with 51 months in eyes with no treatment (p=0.005). CONCLUSIONS: Treatment with ATT halved the risk of uveitis recurrence and delayed the onset of the first recurrence in eyes with uveitis associated with latent TB