Toxicity and toxicokinetics of cadmium in \u3ci\u3eCapitella\u3c/i\u3e sp. I: Relative importance of water and sediment as routes of cadmium uptake

The importance of dissolved versus sediment-bound cadmium as uptake routes for the deposit-feeding polychaete Capitella species I and the toxicity and toxicokinetics of cadmium from these exposure routes were investigated. Effects were reported as changes in worm growth rate, egestion rate and allometry. Radioactive cadmium (109Cd) was used as a tracer to examine the uptake (5 d) and subsequent depuration (6 d) of cadmium. Both effects and kinetics were investigated in systems with and without sediment. Individual Capitella sp. I were exposed to (1) dissolved (i.e. –1). Worms in water-only treatments showed negative growth rates, which decreased linearly from –5 to –10% d–1 with increasing cadmium concentration. Cadmium had no detectable effect on egestion rate or growth in the presence of sediment in either sediment-bound only (ca 36% d–1) or porewater & sediment (ca 30% d–1) treatments. Cadmium exposure had no detectable effect on the allometric exponent (i. e. area-length relation) in any of the treatments; however, worms in water-only treatments were relatively thinner than in the 2 treatments with sediment. Worms in porewater & sediment treatments took up ca 50-fold more cadmium (ca 195 ng Cd worm–1) than worms in water-only treatments (3.9 ng Cd worm–1) during 5 d of exposure. Sediment-bound cadmium was calculated to contribute 95 % of the total amount taken up by feeding worms. Starving worms retained all of the cadmium during the subsequent depuration period (6 d), and exhibited an increased weight-specific body burden (μg Cd g–1 dry wt worm) due to shrinkage. In feeding worms, the decrease in weight-specific body burden was faster (T½ = 3 d) than the decrease in total body burden (μg Cd worm–1; T½ = 11 d), indicating that both active excretion and dilution of cadmium body burden as a result of growth contributed to the change in cadmium tissue concentration during the depuration period. Thus, our results indicate that in Capitella sp. I sediment-bound cadmium is the major route of uptake. We found that cadmium affects starving but not fed worms, despite the fact that fed worms took up considerably more cadmium than starving worms. Our results suggest that stress associated with food limitation increases the susceptibility of worms to cadmium stress

Toxicity and toxicokinetics of cadmium in \u3ci\u3eCapitella\u3c/i\u3e sp. I: Relative importance of water and sediment as routes of cadmium uptake

The importance of dissolved versus sediment-bound cadmium as uptake routes for the deposit-feeding polychaete Capitella species I and the toxicity and toxicokinetics of cadmium from these exposure routes were investigated. Effects were reported as changes in worm growth rate, egestion rate and allometry. Radioactive cadmium (109Cd) was used as a tracer to examine the uptake (5 d) and subsequent depuration (6 d) of cadmium. Both effects and kinetics were investigated in systems with and without sediment. Individual Capitella sp. I were exposed to (1) dissolved (i.e. –1). Worms in water-only treatments showed negative growth rates, which decreased linearly from –5 to –10% d–1 with increasing cadmium concentration. Cadmium had no detectable effect on egestion rate or growth in the presence of sediment in either sediment-bound only (ca 36% d–1) or porewater & sediment (ca 30% d–1) treatments. Cadmium exposure had no detectable effect on the allometric exponent (i. e. area-length relation) in any of the treatments; however, worms in water-only treatments were relatively thinner than in the 2 treatments with sediment. Worms in porewater & sediment treatments took up ca 50-fold more cadmium (ca 195 ng Cd worm–1) than worms in water-only treatments (3.9 ng Cd worm–1) during 5 d of exposure. Sediment-bound cadmium was calculated to contribute 95 % of the total amount taken up by feeding worms. Starving worms retained all of the cadmium during the subsequent depuration period (6 d), and exhibited an increased weight-specific body burden (μg Cd g–1 dry wt worm) due to shrinkage. In feeding worms, the decrease in weight-specific body burden was faster (T½ = 3 d) than the decrease in total body burden (μg Cd worm–1; T½ = 11 d), indicating that both active excretion and dilution of cadmium body burden as a result of growth contributed to the change in cadmium tissue concentration during the depuration period. Thus, our results indicate that in Capitella sp. I sediment-bound cadmium is the major route of uptake. We found that cadmium affects starving but not fed worms, despite the fact that fed worms took up considerably more cadmium than starving worms. Our results suggest that stress associated with food limitation increases the susceptibility of worms to cadmium stress

Individual physiological responses to environmental hypoxia and organic enrichment: Implications for early soft-bottom community succession

Infaunal inhabitants of coastal marine sediments occupy environments along a continuum from extremely food-rich, low-oxygen regions to food-poor habitats with relatively high levels of available oxygen. In organic-rich sediments, efficient utilization of available organic matter by deposit-feeding macrofauna may often be limited by the supply of oxygen. Specific feeding rate, growth, and production efficiency were measured on single individuals of the polychaete Capitella species 1 to determine whether previously measured declines in growth rates in response to hypoxia were due to decreased feeding, decreased conversion efficiency, or both. Under otherwise constant conditions, feeding rate was determined by the nitrogen content of the sediment, with a greater nitrogen content generally leading to higher specific feeding rates in a manner consistent with recent interpretations of optimal foraging theory. However, the relationship between feeding rate and growth was influenced by oxygen concentration such that in relatively nitrogen-poor sediment, greater growth rates were observed at the lower oxygen level. Simultaneous measurement of growth and feeding rates indicated that the effect of oxygen was due to a decrease in the efficiency with which ingested sediment was converted to tissue under low nitrogen, high oxygen conditions. We suggest that the decreased conversion rate of ingested sediment to body volume under the higher oxygen regime reflected an aerobic metabolic system poised to rapidly exploit available oxygen supplies. The physiological responses measured in our experiments are consistent with the classical faunal successional sequence occurring in a deposit following organic enrichment. When viewed temporally, these faunal changes parallel geochemical changes such that high organic matter, low oxygen conditions give way to higher oxygen levels and decreased concentrations of organic matter. Thus environmental conditions typically change toward those under which Capitella sp. 1 would be expected to perform most poorly. We suggest that an underlying physiological mechanism in Capitella spp. may strongly influence the early successional changes observed following the organic enrichment of soft-bottom benthic environments

Aortic dilatation after endovascular repair of blunt traumatic thoracic aortic injuries

ObjectiveEndovascular repair of blunt traumatic thoracic aortic injuries (BTAI) has become routine at many trauma centers despite concerns regarding durability and aortic dilatation in these predominantly young patients. These concerns prompted this examination of thoracic aortic expansion after endovascular repair of a BTAI.MethodsThe immediate postoperative and most recent computed tomography (CT) scans of patients who had undergone urgent endovascular repair of a BTAI and had at least 1 year of follow-up were reviewed. Diameter measurements were made at four predetermined sites: immediately proximal to the left subclavian artery (D1), immediately distal to the left subclavian artery (D2), distal extent of the endograft (D3), and 15 mm beyond the distal end of the endograft (D4). Split screens permitted direct comparison of measurements between CTs at the corresponding levels.ResultsDuring a 6-year period (2001-2007), 21 patients (mean age, 42.9 years; range, 19-81 years) underwent endovascular repair of a BTAI, 17 with at least 1 year of follow-up (mean, 2.6 years; range, 1-5.5 years). No patients required reintervention during this period. The mean rate of dilatation for each level of the thoracic aorta in mm/year was: D1, 0.74 (95% confidence interval [CI], 0.42-1.06); D2, 0.83 (95% CI, 0.55-1.11); D3, 0.63 (95% CI, 0.37-0.89); D4, 0.47 (95% CI, 0.27-0.67). The rate of expansion of D2 differed significantly vs D4 (P = .025).ConclusionsDuring the first several years of follow-up, the proximal thoracic aorta dilates minimally after endovascular repair of BTAIs, with the segment just distal to the left subclavian artery expanding at a slightly greater rate. Longer-term follow-up is necessary to determine whether this expansion continues and becomes clinically significant

Effectiveness of herpes zoster vaccination in an older United Kingdom population.

BACKGROUND: Vaccination against herpes zoster was introduced in the United Kingdom in 2013 for individuals aged 70 years, with a phased catch-up campaign for 71-79 year olds. Vaccine introduction has resulted in a marked fall in incident herpes zoster and in post-herpetic neuralgia (PHN), but formal evaluation of vaccine effectiveness is needed. METHODS: In a population-based cohort study of older individuals born between 1933 and 1946, we used linked UK anonymised primary care health records for the first three years of the vaccination programme (01/09/2013-31/08/2016) and multivariable Poisson regression to obtain incidence rates and vaccine effectiveness (VE) against zoster and PHN. RESULTS: Among 516,547 individuals, 21% were vaccinated. Incidence of zoster was 3.15/1000 person-years in vaccinees and 8.80/1000 person-years in unvaccinated individuals. After adjustment, VE was 64% (95%CI = 60-68%) against incident zoster and 81% (95%CI = 61-91%) against PHN, with very similar VE estimates in the routine and catch-up cohorts. VE against zoster was lower in those with a previous history of zoster: 47% (95%CI = 31-58%) versus 64% (95%CI = 60-68%) in those without previous zoster. There was evidence of waning VE over time, from 69% (95%CI = 65-74%) in the first year after vaccination to 45% (95%CI = 29-57%) by the third year. CONCLUSION: This first formal assessment of VE in the UK zoster vaccination programme demonstrates good effectiveness of zoster vaccine, and very good protection against PHN. The findings provide evidence that VE is similar across the age groups targeted for vaccination in the UK, and on duration of protection of the vaccine in public health use. The study provides key information for decision-makers about the future direction of UK zoster vaccination programme, indicating that the live zoster vaccine may be more cost-effective than estimated previously. It also supports efforts to communicate the benefits of zoster vaccination to address the declining coverage observed across the UK