Conservation of thermal physiology in tropical intertidal snails following an evolutionary transition to a cooler ecosystem: climate change implications

Predictions for animal responses to climate warming usually assume that thermal physiology is adapted to present-day environments, and seldom consider the influence of evolutionary background. Little is known about the conservation of warm-adapted physiology following an evolutionary transition to a cooler environment. We used cardiac thermal performance curves (cTPCs) of six neritid gastropod species to study physiological thermal trait variation associated with a lineage transition from warmer rocky shores to cooler mangroves. We distinguished between functional thermal performance traits, related to energy homeostasis (slope gradient, slope curvature, HRmax, maximum cardiac activity and Topt, the temperature that maximizes cardiac activity) and a trait that limits performance (ULT, the upper lethal temperature). Considering the theory of optimal thermal performance, we predicted that the functional traits should be under greater selective pressure to change directionally and in magnitude than the thermal limit, which is redundant in the cooler environment. We found little variation in all traits across species, habitats and ecosystems, despite a ~20°C reduction in maximum habitat temperature in the mangrove species over 50 million years. While slope gradient was significantly lowered in the mangrove species, the effect difference was negated by greater thermal plasticity in the rocky shore species. ULT showed the least variation and suggested thermal specialization in the warmest habitat studied. The observed muted variation of the functional traits among the species may be explained by their limited role in energy acquisition and rather their association with heat tolerance adaptation, which is redundant in the mangrove species. These findings have implications for the conservation of habitat of intertidal gastropods that transition to cooler environments. Furthermore, they highlight the significance of evolutionary history and physiological conservation when predicting species responses to climate change.

Tracking coastal acidification from erosion of gastropod shells: spatial sensitivity and organism size effect

The rapidly changing marine environmental chemistry associated with growing industrialisation, urban population expansion, and the unabated rise in atmospheric CO₂ necessitates monitoring. Traditional approaches using metres, dataloggers, and buoys to monitor marine acidification have limited application in coastal oceans and intertidal zones subjected to direct wave action. The present study trialled a system to biomonitor coastal acidification (carbonate ion and pH) based on the dissolution of living gastropod shells. We extended on an approach that ranked shell erosion (SER) in Nerita chamaeleon (Nc) in environments where such erosion was found to correlate with exposure to acidified water. We assessed the spatial scale at which the Nc-SER marker could detect change in acidification along rocky shores, and whether snail body size affected this marker. We found that proportional and unique Nc-SERs not only varied between acidified and non-acidified reference shores at a coarse spatial scale (10 km), but also in predictable ways at fine scales (metres), vertically and horizontally within a shore. Differences between acidified and reference shores in the relationship for snail size and Nc-SER were accentuated by less weathered shells at reference localities, highlighting the value of including small, juvenile snails in monitoring protocols. Gastropod shells are shown to be useful for assessing point sources of acidification and the spatial area of affected coastal zones. This cost-effective and easy-to-use approach (potentially even by citizen-scientists) offers an early warning system of acidification of rocky shore ecosystems, where the deployment of instruments is precluded.

The neritid snails of Brunei Darussalam: their geographical, ecological and conservation significance

Neritid snails are diverse and conspicuous in tropical coastal environments. They can serve as indicators of environmental change and can provide conservation information. In the present review of the neritid species of Brunei Darussalam, we report sixteen species, including seven new records from estuarine, mangrove and rocky-shore habitats. These records update distributions across the Central Indo-Pacific realm, specifically the Palawan/North Borneo ecoregion. Under-sampling, species misidentifications and locally-rare species undermine the accuracy of records in previous studies for the region. Three of the rocky-shore and two of the mangrove species collected here are represented by single specimens; these rocky-shore species are possible colonizers from neighbouring regions and the scarcity of the mangrove species likely refers to under-sampling. We present novel shell characteristics that readily distinguish between Neripteron violaceum and Nerip. cornucopia. We describe the ecology and habitat use of the Brunei species and discuss conservation issues.

Evaluating Postgraduate Surgical Education Experience, Professional Satisfaction and Personal Well-Being: A Cross-Sectional Survey of Trainees in A Low-Middle Income Country in Sub-Saharan Africa

BACKGROUND

Education at the postgraduate level is important in grooming competent specialists in different fields of surgical care. This study aimed to evaluate the training experience, professional satisfaction, and personal well-being of postgraduate surgical residents in northern Nigeria.

SUBJECTS, MATERIALS AND METHODS

It was a cross-sectional survey of 157 medical doctors enrolled for a minimum of 6 months in surgical residency training in tertiary hospitals in the northern zone of the country. All participants filled a pre-tested questionnaire and their responses were analyzed using Statistical Package for the Social Sciences version 20.

RESULTS

The respondents had a mean age of 34.4 ± 4.8 years. Thirty-two (20.5%) agreed that there was a balance between their training needs and rotation for clinical services. There was a marked disparity between the median time allocated for non-ward-based training activities (4.0 hours each per week) and the average time allocated for research activities (1.0 hours per week). Although 89 (57.4%) and 82 (53.3%) reported fair satisfaction in their professional role and private life respectively, a larger proportion expressed poor satisfaction with their participation in recreational (107 [68.6%]) and social activities (90 [58.4%]). One hundred and seventeen (74.5%) stated that a high level of stress was associated with their training.

CONCLUSIONS

The surgical residents experienced relatively more training on patient management than on research work. Although their educational experience was associated with a high level of stress in majority of them, most of the trainees expressed fair satisfaction with activities in their professional role and private life.

Efficacy of leflunomide in the treatment of vasculitis

OBJECTIVES

Only a few small case series, case reports, and one small clinical trial suggested some benefit of leflunomide (LEF) in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and other vasculitides. We analysed the clinical efficacy and tolerability of LEF in a large cohort of patients with various vasculitides.

METHODS

This was a retrospective analysis of patients who received LEF for treatment of their vasculitis enrolled in the Vasculitis Clinical Research Consortium (VCRC) Longitudinal Study and in 3 additional centres from the Canadian vasculitis research network (CanVasc).

RESULTS

Data for 93 patients were analysed: 45 had granulomatosis with polyangiitis (GPA), 8 microscopic polyangiitis (MPA), 12 eosinophilic granulomatosis with polyangiitis (EGPA), 14 giant-cell arteritis (GCA), 9 Takayasu's arteritis (TAK), and 5 polyarteritis nodosa (PAN). The main reason for initiation of LEF was active disease (89%). LEF was efficacious for remission induction or maintenance at 6 months for 62 (67%) patients (64% with GCA, 89% with TAK, 80% with PAN, 69% with GPA, 75% with MPA, 33% with EGPA); 20% discontinued LEF before achieving remission because of persistent disease activity. Overall, 22 adverse events (gastrointestinal symptoms being the most common) led to drug discontinuation in 18 (19%) patients, of which 12 stopped LEF before month 6, before showing any benefit in 8/12 of these patients.

CONCLUSIONS

Leflunomide can be an effective therapeutic option for various vasculitides, especially for non-severe refractory or relapsing ANCA-associated vasculitis or large-vessel vasculitis. No new safety signals for LEF were identified in this population.

Biomonitoring acidification using marine gastropods

Ocean acidification is mainly being monitored using data loggers which currently offer limited coverage of marine ecosystems. Here, we trial the use of gastropod shells to monitor acidification on rocky shores. Animals living in areas with highly variable pH (8.6-5.9) were compared with those from sites with more stable pH (8.6-7.9). Differences in site pH were reflected in size, shape and erosion patterns in Nerita chamaeleon and Planaxis sulcatus. Shells from acidified sites were shorter, more globular and more eroded, with both of these species proving to be good biomonitors. After an assessment of baseline weathering, shell erosion can be used to indicate the level of exposure of organisms to corrosive water, providing a tool for biomonitoring acidification in heterogeneous intertidal systems. A shell erosion ranking system was found to clearly discriminate between acidified and reference sites. Being spatially-extensive, this approach can identify coastal areas of greater or lesser acidification. Cost-effective and simple shell erosion ranking is amenable to citizen science projects and could serve as an early-warning-signal for natural or anthropogenic acidification of coastal waters.

Non-reversible and Reversible Heat Tolerance Plasticity in Tropical Intertidal Animals: Responding to Habitat Temperature Heterogeneity

The theory for thermal plasticity of tropical ectotherms has centered on terrestrial and open-water marine animals which experience reduced variation in diurnal and seasonal temperatures, conditions constraining plasticity selection. Tropical marine intertidal animals, however, experience complex habitat thermal heterogeneity, circumstances encouraging thermal plasticity selection. Using the tropical rocky-intertidal gastropod, Echinolittorina malaccana, we investigated heat tolerance plasticity in terms of laboratory acclimation and natural acclimatization of populations from thermally-dissimilar nearby shorelines. Laboratory treatments yielded similar capacities of snails from either population to acclimate their lethal thermal limit (LT50 variation was ∼2°C). However, the populations differed in the temperature range over which acclimatory adjustments could be made; LT50 plasticity occurred over a higher temperature range in the warm-shore snails compared to the cool-shore snails, giving an overall acclimation capacity for the populations combined of 2.9°C. In addition to confirming significant heat tolerance plasticity in tropical intertidal animals, these findings reveal two plasticity forms, reversible (laboratory acclimation) and non-reversible (population or shoreline specific) plasticity. The plasticity forms should account for different spatiotemporal scales of the environmental temperature variation; reversible plasticity for daily and tidal variations in microhabitat temperature and non-reversible plasticity for lifelong, shoreline temperature conditions. Non-reversible heat tolerance plasticity, likely established after larvae settle on the shore, should be energetically beneficial in preventing heat shock protein overexpression, but also should facilitate widespread colonization of coasts that support thermally-diverse shorelines. This first demonstration of different plasticity forms in benthic intertidal animals supports the hypothesis that habitat heterogeneity (irrespective of latitude) drives thermal plasticity selection. It further suggests that studies not making reference to different spatial scales of thermal heterogeneity, nor seeking how these may drive different thermal plasticity forms, risk misinterpreting ectothermic responses to environmental warming.

Substantial heat tolerance acclimation capacity in tropical thermophilic snails, but to what benefit?

The theory for thermal acclimation of ectotherms suggests that (1) heat tolerance is traded off for thermal acclimation in thermophilic species and that (2) plasticity is constrained in tropically distributed ectotherms, which commonly experience relatively thermally stable environments. We observed substantial heat tolerance plasticity in a test of this theory using tropical, thermophilic marine intertidal snails that inhabit extremely hot and highly variable thermal environments. The implication of these results is that plasticity selection is largely driven by habitat temperature conditions irrespective of basal heat tolerance or latitude. However, heat tolerance of field-fresh snails was comparable with that of laboratory warm-acclimated snails, suggesting that snails in the field may often be unable to improve heat hardening with further environmental warming. These findings suggest that field referencing is crucial to using laboratory-measured acclimation capacity when inferring climate warming vulnerability in ectotherms, and overall they question how well current thermal biology theory predicts the outcomes of global change in intertidal environments.

Cytotoxic, genotoxic and antigenotoxic potencies of oligorutins

Rutin has been enzymatically oligomerized by laccase from Trametes versicolor. Five fractions of oligomers were obtained from the monomers having high solubility in water, which can reach 351-times that of rutin. Cytotoxicity of rutin and oligorutin fractions was evaluated towards K562 cells. Oligorutin fractions showed a lower antiproliferative effect compared with its monomer. The genotoxic potential of rutin and oligorutin fractions was assessed, at the limit of the solubility of each molecule, using the comet test. None of the tested concentrations of either rutin or oligorutin fractions has showed a genotoxic effect. Similarly, the antigenotoxic effect of these flavonoids was tested using the same assay. The obtained results showed a higher ability of oligorutin fractions to reduce the genotoxicity induced by hydrogen peroxide compared with monomeric rutin.

Health care for the disadvantaged: some preliminary observations of health centres in Trinidad and Tobago

This study seeks to identify background characteristics of the people who utilise health centre services in Trinidad and Tobago and to investigate their perceptions of the services offered. Data were obtained through a survey of health centre users distributed throughout Trinidad and Tobago. Multi-stage sampling was used to select 1500 health centre users and structured interviews were conducted on regular clinic days by trained personnel. Results indicate that there are fairly high levels of patient satisfaction with health centres in Trinidad and Tobago and that the more disadvantaged groups (the elderly, women and the unemployed) utilise these services more frequently. Results also show variations with respect to care received, frequency of attendance, amount willing to pay, services that need improving and doctor's willingness to listen to problems.

Patients' perception and satisfaction with health care professionals at primary care facilities in Trinidad and Tobago

This paper endeavours to identify the background characteristics of health centre users in Trinidad and Tobago and their perceptions of the efficiency of the services provided. Multistage sampling was employed to select 1451 users. Data were obtained during structured interviews on regular clinic days. Of the people using the health centres, 80.4% were unemployed and 75.9% were women. People aged over 60 accounted for 25.4% of the sample. Users included a disproportionately high number of persons from the lower socioeconomic categories. The proportions of persons of different ethnic and religious groups closely reflected those in the country's general population. Approximately 74% of the interviewees were satisfied with the performance of the doctors in the health centres. For nurses the satisfaction rating was about 10% higher. The greatest needs for improvement were perceived to be in pharmacists' and doctors' services, with particular reference to waiting times.

Patient satisfaction at health centres in Trinidad and Tobago

The aim of this paper is to identify background characteristics of health centre users in Trinidad and Tobago and their perceptions of the services provided. Multi-staged sampling was used to select 1,500 health centre users throughout the country. Data were obtained using structured interviews conducted on regular clinic days. Results show that there is an overwhelmingly large percentage of unemployed persons (80.4%) and women (75.9%) among the users of health centres. The elderly is well represented, with 25.4 percent of the sample being over 60 years of age. Also, occupational status of family wage earners and educational attainment levels of respondents reflect a disproportionately higher number from lower socio-economic groupings among health centre users. On the other hand, proportions of different ethnic and religious groups among the respondents bear a striking similarity to the general population of Trinidad and Tobago. Respondents appear to be generally satisfied with the services of the health centres. When the categories for "satisfied' and "very satisfied' were combined, results show that 73.0% of respondents were satisfied with the comfort of the health centre, 81.7% with the ease and convenience of getting to the health centre and 67.4% with the medical care received at the health centre. According to respondents' opinions, the services in greatest need of improvement are the pharmacy and doctor services, especially through reducing the long waiting period. When the doctors, nurses and pharmacists were compared with respect to "courtesy and consideration', "Skills and Competence' and "advice provided', results show that the generally high levels of satisfaction are remarkably similar in all three cases.

Some factors associated with substance abuse among secondary school students in Trinidad and Tobago

This study attempts to investigate factors associated with involvement in substance abuse in Trinidad and Tobago, through a survey of 1603 secondary school students, aged fourteen to eighteen years. Analysis of the data using the Chi-square test indicates a significant association (p < .001) between involvement in substance abuse and the following factors: grades at school, importance of religious involvement, amount of spending money obtained, confidence placed in parents/peers, parental involvement in alcohol consumption and educational expectations. Generally, the study indicates that youth less committed to traditional values, show a greater tendency to be involved in substance abuse. Involvement also appears to be associated with low self esteem and low educational expectations.

A clinical experience with a hierarchically controlled myoelectric hand prosthesis with vibro-tactile feedback

Improved performance of externally powered myoelectric hands is possible when the direct control of the digit flexion and grip force are given over to an electronic controller which frees the operator to concentrate on other demands.

DESIGN

A commercial myoelectric hand was modified to take the new touch and slip sensors and novel control method.

SUBJECT

An adult male with a traumatic mid-forearm amputation.

OUTCOME MEASURE

The range and ease of use of the prosthetics system.

RESULT

The hand was easily and usefully operated in the home and work environment.

CONCLUSION

Hierarchical control of a hand is possible using sensory feedback to a sophisticated electronic controller. Such a control method reduces the demands on the user's concentration and enhances the hand's range.

Ileal urinary diversion in patients with Renal transplants

Ileal urinary diversion has been carried out on 8 occasions in 7/215 kidney transplant patients. In six instances the diversion was required either because the bladder had previously been removed or there was gross abnormality of the outflow tract: in 2 it was successfully employed to deal with difficult post-transplantation urinary fistulae. 4 patients died: 3 within 2 months and 1 at 9 months after the operation. Infection with organisms indistinguishable from those cultured from the ileal loop, was a common complication and, although there were other significant factors which contributed to the mortality, retrospective consideration suggests that energetic prophylactic antibacterial therapy should be instituted when kidney transplantation with ileal urinary diversion is undertaken.