Search

Abstract: This study investigated the internal osmotic regulatory capabilities of the Manila clam (Ruditapes philippinarum) following in vivo exposure to a range of salinities. A second objective was to measure the health status of the Manila clam following exposure to different salinities using the neutral red retention (NRR) assay, and to compare results using a range of physiological saline solutions (PSS). On exposure to seawater of differing salinities, the Manila clam followed a pattern of an osmoconformer, although they seemed to partially regulate their circulatory haemolytic fluids to be hyperosmotic to the surrounding aqueous environment. Significant differences were found when different PSS were used, emphasizing the importance of using a suitable PSS to reduce additional osmotic stress. Using PSS in the NRR assay that do not exert additional damage to lysosomal membrane integrity will help to more accurately quantify the effects of exposure to pollutants on the organism(s) under investigation. [Copyright &y& Elsevier]

Abstract: Microcystins are produced by bloom-forming cyanobacteria and pose significant health and ecological problems. To investigate the impacts of these biotoxins on the physiology of the zebra mussels, Dreissena polymorpha, a series of short-term feeding experiments were conducted in the laboratory. We used five microalgal diets consisting of single-cell suspensions of the green algae, Chlorella vulgaris, the diatom, Asterionella formosa, the cryptophyte, Cryptomonas sp. and two strains of the toxic cyanobacterium, Microcystis aeruginosa (strains CCAP 1450/06 and CCAP 1450/10). A sixth diet was a mixture of the diatom and the CCAP 1450/10 cyanobacterial strain. The low-toxicity strain CCAP 1450/06 contained 7.4μgl−1 of the MC-LR variant while the very toxic strain CCAP 1450/10 contained 23.8μgl−1 of MC-LR and 82.9μgl−1 of MC-LF. A flow-through system was designed to measure the following feeding parameters: clearance, filtration, ingestion and absorption rates. Ultimately the scope for growth (SFG) was determined as a net energy balance. We observed that mussels cleared the cyanobacterial species containing MC-LF (mean±95% confidence interval) at a significant lower rate (498±82mlh−1 g−1 for the single cell suspension and 663±100mlh−1 g−1 for the mixture diet) than all of the non-toxic species and the cyanobacterium containing MC-LR (all above 1lh−1 g−1). The same pattern was observed with all the feeding parameters, particularly absorption rates. Furthermore, MC-LF caused an acute irritant response manifested by the production of ‘pseudodiarrhoea’, unusually fluid pseudofaeces, rich in mucus and MC-LF-producing Microcystis cells, ejected through the pedal gape of the mussels. This overall response therefore demonstrates selective rejection of MC-LF-producing cyanobacteria by zebra mussels, enhancing the presence of the very toxic MC-LF-producing M. aeruginosa in mixed cyanobacterial blooms and in the benthos. Finally, we observed that the SFG (mean±95% confidence interval) of mussels feeding on M. aeruginosa containing MC-LF was significantly lower (34.0±18.8Jh−1 g−1 for the single cell suspension and 83.1±53.0Jh−1 g−1 for the mixture diet) than for mussels ingesting non-toxic diets, except for C. vulgaris (all above 200Jh−1 g−1). This reveals a sublethal, stressful effect of microcystins (particularly MC-LF) on the feeding behaviour and energy balance of the zebra mussel. [Copyright &y& Elsevier]

Tissue fluid osmolarity of flatworms kept with moist bark was 243±4 S.E.M. mOsm kg−1. Tissue fluid osmolarity of those kept with water-saturated tissue paper was 205±5 S.E.M. mOsm kg−1. Flatworms placed in water of 300 and 400 mOsm kg−1 lost weight. Those placed in water of 0, 100 and 200 mOsm kg−1 gained weight. This suggests that body tissue fluids were approximately 260 mOsm kg−1. Tissue fluids were slightly hyperosmotic in external media of 200, 300 and 400 mOsm kg−1, and strongly hyperosmotic at 0 and 100 mOsm kg−1. The highest measured value of tissue osmolarity was 457 mOsm kg−1 from a specimen in a medium of 400 mOsm kg−1. The lowest value was 145 mOsm kg−1 from a specimen in pure water. Transverse sections of flatworms from different media concentrations suggest that fluids are absorbed into or removed from all tissues. [Copyright &y& Elsevier]

Background & Aims: Simultaneous agonism of the μ-opioid receptor and antagonism of the δ-opioid receptor can reduce abdominal pain and diarrhea in patients with irritable bowel syndrome with diarrhea (IBS-D) without constipating side effects. We evaluated the efficacy and safety of a minimally absorbed, μ-opioid receptor agonist and δ-opioid receptor antagonist (eluxadoline) in a phase 2 study in patients with IBS-D. Methods: We randomly assigned 807 patients to groups that received oral placebo twice daily or 5, 25, 100, or 200 mg oral eluxadoline for 12 weeks. The primary end point was clinical response at week 4, defined by a mean reduction in daily pain score from baseline of ≥30%, and of at least 2 points on 0−10 scale, as well as a stool consistency score of 3 or 4 on the Bristol Stool Scale (1–7) for at least 66% of daily diary entries during that week. Results: Significantly more patients receiving 25 mg (12.0%) or 200 mg (13.8%) eluxadoline met the primary end point of clinical response than patients given placebo (5.7%; P < .05). Patients receiving eluxadoline at 100 mg and 200 mg also had greater improvements in bowel movement frequency and urgency, global symptoms, quality of life, and adequate relief assessments (P < .05). Additionally, patients receiving 100 mg (28.0%) or 200 mg (28.5%) eluxadoline were significantly more likely than those receiving placebo (13.8%; P < .005) to meet the US Food and Drug Administration response end point during the full 12 weeks of the study. Eluxadoline was well tolerated with a low incidence of constipation. Conclusions: In a phase 2 study of the mixed μ-opioid receptor agonist/δ-opioid receptor antagonist eluxadoline vs placebo in patients with IBS-D, patients given eluxadoline were significantly more likely to be clinical responders, based on a composite of improvement in abdominal pain and stool consistency. Further study of eluxadoline is warranted to assess its potential as a treatment for IBS-D. ClinicalTrials.gov number, NCT01130272 [Copyright &y& Elsevier]

Most orthopaedic procedures involve high-speed tools, which can cause thermal necrosis of bone. Blunt instruments are likely to generate more heat, thereby increasing the chances of thermal necrosis. This could greatly compromise the outcome of even the best prosthesis in good surgical hands. In today's age a lot of emphasis is laid on high performance and longevity of the implant. Therefore, it is worthwhile that we consider the relevance and importance of instrument sharpening. We carried out a survey across hospitals in UK to find out whether they follow any guidelines or protocol with regards to instrument sharpening. Upto 75% of hospitals did not follow any guideline or policy, while 20% of hospitals carried out some sort of quality checks on instruments. This implies that there could be a significant risk of suboptimal outcome due to unnecessary osteonecrosis that can affect most operative orthopaedic interventions, particularly joint arthroplasties. Blunt instruments are too common in orthopaedic theatres and this problem needs to be addressed. Our study brings to light the fact that there seems to be no consensus on this issue and there is theoretically a significant risk of suboptimal outcome because of unnecessary osteonecrosis. This potentially may affect the long and short-term results even in good hands and with excellent prosthesis (cemented or uncemented). [ABSTRACT FROM AUTHOR]

Abstract: In this laboratory study, dogwhelks (Nucella lapillus) were collected from the intertidal zone and exposed to 16 °C (ambient), 26.5 °C and 30 °C under normal and hyperoxic conditions respectively. It was shown that there was no thermally induced mortality at 26.5 °C, but that the mortality rate was 40–50% in 30 °C. This mortality rate was reduced to 10% if extra oxygen was provided, indicating that oxygen supply was setting the limit for whole organism thermal tolerance. Tissue samples were then analysed for protein features using two-dimensional gel electrophoresis, and both up and down regulation of proteins were visualised by silver staining and crosswise comparisons of gels from control vs. treated animals. The results clearly show that the protein profiles from dogwhelks exposed to increased water temperatures differ from those of the control, but that increased oxygen availability alleviates these differences thus increasing the similarity between heat-shocked and control animal protein pattern. This implies a more stable protein metabolism and might explain the increased survival of heat-shocked individuals when extra oxygen is supplied. [Copyright &y& Elsevier]

A sample of 166 conger eel, Conger conger (Linnaeus, 1758) were captured between August 1998 and June 1999, from the inshore south coastal waters of Ireland using demersal trawl, longlines, lobster and shrimp pots. The range in length was 33–159 cm and weight was 0.05–12.0 kg. Age, determined from vertebrae and sagittal otoliths, ranged from 4 to 20 years. Vertebrae were found to be the most effective tool for ageing. A linear relationship was found between total length and otolith radius. A curvilinear model best described the relationship between total length and vertebral radius. Both otoliths and vertebrae were used in the back-calculation technique and the von Bertalanffy growth function was fitted. Population growth curves were constructed from both vertebral and otolith measurements. Growth parameters, L∞ and k were estimated for individual fish showing large ranges in values. L∞ from otoliths ranged from 170 to 320 m, and k from 0.01 to 0.09. From vertebrae, L∞ ranged from 130 to 390 m and k from 0.01 to 0.13. Population estimates from otoliths gave results of L∞=271 cm, k=0.037, t0=−1.396 and from vertebrae gave results of L∞=214 cm, k=0.059, t0=−1.960. Condition factor ranged from 0.03 to 1.73 and gonadosomatic index from 0.53 to 7.05. The greatest increase in condition occurred between summer and autumn, while the greatest increase in gonadosomatic index occurred between autumn and winter. It was not possible to determine the sex of the eels from gross gonad appearance. Histological analysis of the gonads revealed that all conger eels were female. The absence of males and of ripe or spent females in the inshore south coastal inshore waters suggests that conger eels leave this region to spawn. This study has provided the first published data on age, growth and gonad development of a population of the species in the Northeast Atlantic. [Copyright &y& Elsevier]