Temperature responses vary between riffle beetles from contrasting aquatic environments.

Organisms living in environmentally stable ecosystems are hypothesized to exhibit narrow environmental tolerance ranges; however, previous experiments testing this prediction with invertebrates in spring habitats are equivocal. Here we examined the effects of elevated temperatures on four riffle beetle species (family: Elmidae) native to central and west Texas, USA. Two of these, Heterelmis comalensis and Heterelmis cf. glabra are known to occupy habitats immediately adjacent to spring openings and are thought to have stenothermal tolerance profiles. The other two, Heterelmis vulnerata and Microcylloepus pusillus are surface stream species with more cosmopolitan distributions and are assumed to be less sensitive to variation in environmental conditions. We examined performance and survival of elmids in response to increasing temperatures using dynamic and static assays. Additionally, changes in metabolic rate in response to thermal stress were assessed for all four species. Our results indicated that spring-associated H. comalensis is most sensitive while the more cosmopolitan elmid M. pusillus is least sensitive to thermal stress. However, there were differences in temperature tolerances among the two spring-associated species: H. comalensis had relatively narrow thermal tolerance in comparison to H. cf. glabra. This could be due to differences in the climatic and hydrological conditions in the geographical regions which the respective riffle beetle populations reside. However, despite these differences, H. comalensis and H. cf. glabra showed a dramatic increase in their metabolic rates with increasing temperatures indicating that these species are indeed spring specialists and likely have a stenothermal profile.

Effect of trophic position on mercury concentrations in bottlenose dolphins (Tursiops truncatus) from the northern Gulf of Mexico.

Marine species from the Gulf of Mexico often have higher mercury (Hg) concentrations than conspecifics in the Atlantic Ocean. Spatial differences in Hg sources, environmental conditions, and microbial communities influence both Hg methylation rates and the bioavailability of Hg to organisms at the base of the food web. Mercury bioaccumulates within organisms and biomagnifies in marine food webs, and therefore reaches the greatest concentrations in long-lived marine carnivores, such as dolphins. In this study, we explored whether differences in trophic position and foraging habitat among bottlenose dolphins (Tursiops truncatus) from the northern Gulf of Mexico (nGoM) contributed to the observed variation in skin total Hg (THg) concentrations. Using the δ13C and δ34S values in dolphin skin, we assigned deceased stranded dolphins from Florida (FL; n = 29) and Louisiana (LA; n = 72) to habitats (estuarine, barrier island, and coastal) east and west of the Mississippi River Delta (MRD). We estimated the mean trophic position of dolphins from each habitat using δ15N values from stranded dolphin skin and tissues of primary consumers taken from the literature following a Bayesian framework. Finally, we compared trophic positions and THg concentrations among dolphins from each habitat, accounting for sex and body length. Estimated marginal mean THg concentrations (µg/g dry weight) were greatest in dolphins assigned to the coastal habitat and estuarine habitats east of the MRD (range: 2.59-4.81), and lowest in dolphins assigned to estuarine and barrier island habitats west of the MRD (range: 0.675-0.993). On average, dolphins from habitats with greater THg concentrations also had higher estimated trophic positions, except for coastal dolphins. Our results suggest that differences in trophic positions and foraging habitats contribute to spatial variability in skin THg concentrations among nGoM bottlenose dolphins, however, the relative influence of these factors on THg concentrations are not easily partitioned.

Interactions at surface-subterranean ecotones: structure and function of food webs within spring orifices.

Spring orifices are ecotones between surface and subterranean aquatic ecosystems. Invertebrates of different origins (e.g., surface, spring obligate, and subterranean) coexist in these spatially restricted environments, potentially competing for resources. However, processes that allow for population coexistence in these presumably low resource environments are not well understood. We examined invertebrate communities at two spring complexes in Texas, USA and assessed resource use and food web structure at spring orifices using stable isotopes of carbon (δ13C) and nitrogen (δ15N). Using bulk δ13C and δ15N of organisms and potential food sources, we elucidated dietary sources and found that invertebrate communities exhibited resource partitioning and contained two main food chains (periphyton versus terrestrial organic matter [OM]). In both spring complexes, several endemic spring orifice associated and subterranean taxa derived most of their diet from terrestrial OM. Analysis of compound-specific stable isotopes (i.e., δ13C of essential amino acids, EAAs) from two co-occurring elmid species indicated that the endemic spring orifice-associated species (Heterelmis comalensis) derived > 80% of its EAAs from bacteria, whereas the widespread surface species (Microcylloepus pusillus) derived its EAAs from a more equitable mix of bacteria, fungi, and algae. We additionally calculated niche overlap among of several taxonomically related groups (aquatic beetles and amphipods) that co-occur in spring ecotones and posterior probability estimates indicated little to no niche overlap among related species. Results indicate that invertebrates at subterranean-surface aquatic ecotones are partitioning food resources and highlight the importance of connections to riparian zones for persistence of several endemic invertebrates.

Chemolithoautotrophy supports macroinvertebrate food webs and affects diversity and stability in groundwater communities.

The prevailing paradigm in subterranean ecology is that below-ground food webs are simple, limited to one or two trophic levels, and composed of generalist species because of spatio-temporally patchy food resources and pervasive energy limitation. This paradigm is based on relatively few studies of easily accessible, air-filled caves. However, in some subterranean ecosystems, chemolithoautotrophy can subsidize or replace surface-based allochthonous inputs of photosynthetically derived organic matter (OM) as a basal food resource and promote niche specialization and evolution of higher trophic levels. Consequently, the current subterranean trophic paradigm fails to account for variation in resources, trophic specialization, and food chain length in some subterranean ecosystems. We reevaluated the subterranean food web paradigm by examining spatial variation in the isotopic composition of basal food resources and consumers, food web structure, stygobiont species diversity, and chromophoric organic matter (CDOM), across a geochemical gradient in a large and complex groundwater system, the Edwards Aquifer in Central Texas (USA). Mean δ13C values of stygobiont communities become increasingly more negative along the gradient of photosynthetic OM sources near the aquifer recharge zone to chemolithoautotrophic OM sources closer to the freshwater-saline water interface (FWSWI) between oxygenated freshwater and anoxic, sulfide-rich saline water. Stygobiont community species richness declined with increasing distance from the FWSWI. Bayesian mixing models were used to estimate the relative importance of photosynthetic OM and chemolithoautorophic OM for stygobiont communities at three biogeochemically distinct sites. The contribution of chemolithoautotrophic OM to consumers at these sites ranged between 25% and 69% of total OM utilized and comprised as much as 88% of the diet for one species. In addition, the food web adjacent to the FWSWI had greater trophic diversity when compared to the other two sites. Our results suggest that diverse OM sources and in situ, chemolithoautotrophic OM production can support complex groundwater food webs and increase species richness. Chemolithoautotrophy has been fundamental for the long-term maintenance of species diversity, trophic complexity, and community stability in this subterranean ecosystem, especially during periods of decreased photosynthetic production and groundwater recharge that have occurred over geologic time scales.

Prognostic utility of spontaneous erythroid colony formation and JAK2 mutational analysis for thrombotic events in essential thrombocythaemia.

BACKGROUND: Thrombotic events in essential thrombocythaemia (ET) are difficult to predict with current risk stratification based on age and prior history of thrombosis. AIMS: We aimed to assess the predictive value of the JAK2 V617F mutation (JAK2) and spontaneous erythroid colony (SEC) growth for the development of thrombotic events post diagnosis in patients with ET. METHODS: Consecutive patients with ET were retrospectively identified, and clinical and laboratory correlates were evaluated. Thrombotic events were categorized according to their occurrence at or prior to diagnosis (prior thrombosis), and any time post diagnosis of ET (subsequent thrombosis). JAK2 analysis was performed by allele-specific PCR on whole blood or bone marrow. RESULTS: A total of 62 patients was identified, median age 63 years; 67% (41/61) JAK2-positive and 47% (25/53) SEC-positive. Median follow-up was 33 months (range, 1 to 137). JAK2-positive patients showed a trend to increased prior thrombosis (27% vs 5%, P= 0.08), and a significant increase in the development of subsequent thrombosis (5-year event rate 31% vs 6%, P= 0.04), which persisted when stratified for a history of prior thrombosis (P= 0.04). Survival was not affected by JAK2 status. The SEC assay predicted an increased rate of baseline thrombosis (16% vs 0%, P= 0.04), but was not found to be predictive of any subsequent thrombotic events. CONCLUSIONS: Patients with ET who are JAK2-positive by whole blood allele-specific PCR appear to be at increased risk of thrombotic complications, which is independent of a prior history of thrombosis.

Suicide Among the Emergency Medical Systems Occupation in the United States.

INTRODUCTION: Suicide claimed 47,173 lives in 2017 and is the second leading cause of death for individuals 15-34 years old. In 2017, rates of suicide in the United States (US) were double the rates of homicide. Despite significant research funding toward suicide prevention, rates of suicide have increased 38% from 2009 to 2017. Recent data suggests that emergency medical services (EMS) workers are at a higher risk of suicidal ideation and suicide attempts compared to the general public. The objective of this study was to determine the proportionate mortality ratio (PMR) of suicide among firefighters and emergency medical technicians (EMT) compared to the general US working population. METHODS: We analyzed over five million adult decedent death records from the National Occupational Mortality Surveillance database for 26 states over a 10-year non-consecutive period including 1999, 2003-2004, and 2007-2013. Categorizing firefighters and EMTs by census industry and occupation code lists, we used the underlying cause of death to calculate the PMRs compared to the general US decedent population with a recorded occupation. RESULTS: Overall, 298 firefighter and 84 EMT suicides were identified in our study. Firefighters died in significantly greater proportion from suicide compared to the US.working population with a PMR of 172 (95% confidence interval [CI], 153-193, P<0.01). EMTs also died from suicide in greater proportion with an elevated PMR of 124 (95% CI, 99-153), but this did not reach statistical significance. Among all subgroups, firefighters ages 65-90 were found to have the highest PMR of 234 (95% CI, 186-290), P<0.01) while the highest among EMTs was in the age group 18-64 with a PMR of 126 (95% CI, 100-156, P<0.05). CONCLUSION: In this multi-state study, we found that firefighters and EMTs had significantly higher proportionate mortality ratios for suicide compared to the general US working population. Firefighters ages 65-90 had a PMR more than double that of the general working population. Development of a more robust database is needed to identify EMS workers at greatest risk of suicide during their career and lifetime.

Relationship Between Methylmercury Contamination and Proportion of Aquatic and Terrestrial Prey in Diets of Shoreline Spiders.

Terrestrial organisms such as shoreline spiders that consume prey from aquatic food webs can be contaminated with methylmercury (MeHg). However, no studies have examined the relationship between MeHg contamination of shoreline spider taxa and the proportion of aquatic and terrestrial prey in their diets. The present study had 2 objectives: 1) determine concentrations of MeHg in 7 taxa of shoreline spiders, and 2) assess the relationship between concentrations of MeHg in spiders and the proportion of aquatic and terrestrial prey in spider diets. We collected shoreline spiders, emergent aquatic insects, and terrestrial insects from in and around 10 experimental ponds. Methylmercury concentrations were greatest in spiders, intermediate in aquatic insects, and lowest in terrestrial insects. The elevated MeHg concentrations in spiders indicate that they were feeding, at least in part, on emergent aquatic insects. However, variability in MeHg concentration observed among spider taxa suggested that the proportion of aquatic and terrestrial prey in spider diets likely varied among taxa. We estimated the proportion of aquatic and terrestrial prey in the diet of each spider taxon from the nitrogen (δ15 N) and carbon (δ13 C) isotope values of spiders and their potential aquatic and terrestrial prey items. The median proportion of aquatic prey in spider diets varied by almost 2-fold, and MeHg concentrations in shoreline spiders were strongly correlated with the proportion of aquatic prey in their diet. In the present study, we demonstrate for the first time that the degree of connectivity to aquatic food webs determines MeHg contamination of shoreline spiders. Environ Toxicol Chem 2019;38:2503-2508. © 2019 SETAC.

Comparing resource pulses in aquatic and terrestrial ecosystems.

Resource pulses affect productivity and dynamics in a diversity of ecosystems, including islands, forests, streams, and lakes. Terrestrial and aquatic systems differ in food web structure and biogeochemistry; thus they may also differ in their responses to resource pulses. However, there has been a limited attempt to compare responses across ecosystem types. Here, we identify similarities and differences in the causes and consequences of resource pulses in terrestrial and aquatic systems. We propose that different patterns of food web and ecosystem structure in terrestrial and aquatic systems lead to different responses to resource pulses. Two predictions emerge from a comparison of resource pulses in the literature: (1) the bottom-up effects of resource pulses should transmit through aquatic food webs faster because of differences in the growth rates, life history, and stoichiometry of organisms in aquatic vs. terrestrial systems, and (2) the impacts of resource pulses should also persist longer in terrestrial systems because of longer generation times, the long-lived nature of many terrestrial resource pulses, and reduced top-down effects of consumers in terrestrial systems compared to aquatic systems. To examine these predictions, we use a case study of a resource pulse that affects both terrestrial and aquatic systems: the synchronous emergence of periodical cicadas (Magicicada spp.) in eastern North American forests. In general, studies that have examined the effects of periodical cicadas on terrestrial and aquatic systems support the prediction that resource pulses transmit more rapidly in aquatic systems; however, support for the prediction that resource pulse effects persist longer in terrestrial systems is equivocal. We conclude that there is a need to elucidate the indirect effects and long-term implications of resource pulses in both terrestrial and aquatic ecosystems.

Allochthonous subsidy of periodical cicadas affects the dynamics and stability of pond communities.

Periodical cicadas emerge from below ground every 13 or 17 years in North American forests, with individual broods representing the synchronous movement of trillions of individuals across geographic regions. Due to predator satiation, most individuals escape predation, die, and become deposited as detritus. Some of this emergent biomass falls into woodland aquatic habitats (small streams and woodland ponds) and serves as a high-quality allochthonous detritus pulse in early summer. We present results of a two-part study in which we (1) quantified deposition of Brood X periodical cicada detritus into woodland ponds and low-order streams in southwestern Ohio, and (2) conducted an outdoor mesocosm experiment in which we examined the effects of deposition of different amounts of cicada detritus on food webs characteristic of forest ponds. In the mesocosm experiment, we manipulated the amount of cicada detritus input to examine if food web dynamics and stability varied with the magnitude of this allochthonous resource subsidy, as predicted by numerous theoretical models. Deposition data indicate that, during years of periodical cicada emergence, cicada carcasses can represent a sizable pulse of allochthonous detritus to forest aquatic ecosystems. In the mesocosm experiment, cicada carcass deposition rapidly affected food webs, leading to substantial increases in nutrients and organism biomass, with the magnitude of increase dependent upon the amount of cicada detritus. Deposition of cicada detritus impacted the stability of organism functional groups and populations by affecting the temporal variability and biomass minima. However, contrary to theory, stability measures were not consistently related to the size of the allochthonous pulse (i.e., the amount of cicada detritus). Our study underscores the need for theory to further explore consequences of pulsed allochthonous subsidies for food web stability.

Inhibition of human leukocyte elastase. 2. Inhibition by substituted cephalosporin esters and amides.

A variety of 7 alpha-methoxycephalosporin ester and amide sulfones were prepared and tested to determine the structure-activity relations for inhibition of human leukocyte elastase (HLE), a serine protease which has been implicated in several degenerative lung and tissue diseases. The most potent IC50 values were obtained with neutral, lipophilic derivatives, with the esters being more active than the amides. However, the best time-dependent inhibition in this series was observed with the p- and m-carboxybenzyl esters 7b and 7c. These results are discussed in terms of the proposed mechanism of inhibition as well as a molecular modeling study using the recently solved X-ray crystal structure of HLE.

Inhibition of human leukocyte elastase. 3. Synthesis and activity of 3'-substituted cephalosporins.

Several 3'-substituted cephalosporin sulfones were synthesized from 3-(hydroxymethyl)cephalosporin, which was prepared by Ti(OiPr)4 hydrolysis of the corresponding acetate. A method was also developed to prepare a 3-vinylcephalosporin. Some of these compound were found to be potent time-dependent inhibitors of human leukocyte elastase (HLE). The HLE inhibitory activity was correlated with sigma 1 and it was concluded that the potency was determined by the electron-withdrawing ability as well as the size of the substituent. A mechanism for inhibition of HLE by cephalosporin sulfones is proposed.

Orally active beta-lactam inhibitors of human leukocyte elastase-1. Activity of 3,3-diethyl-2-azetidinones.

A thorough analysis of the mechanism of inhibition of human leukocyte elastase (HLE) by a monocyclic beta-lactam and the mechanism of beta-lactam hydrolysis led to the preparation of potent and highly stable inhibitors of HLE. This work led to the identification of 4-[(4-carboxyphenyl)-oxy]-3,3-diethyl-1- [[(phenylmethyl)amino]carbonyl]-2-azetidinone (2) as the first orally active inhibitor of human leukocyte elastase (HLE). Analogs of 2 with different substituents on the urea N were synthesized and evaluated for their activity in vitro against HLE as well as in vivo in a hamster lung hemorrhage model. Compounds with a methyl or a methoxy group in the para position of the benzene ring were very potent in both assays. The results are discussed on the basis of the proposed model for the binding of this class of inhibitors to HLE and a possible mechanism of inhibition is presented.

Orally active beta-lactam inhibitors of human leukocyte elastase. 2. Effect of C-4 substitution.

The effect of changing the C-4 substituent of 3,3-diethyl-1-[(benzylamino)carbonyl]-2-azetidinone on inhibition of HLE and in a model of HLE-induced lung damage in hamsters was explored. Substituents at this position do not appear to interact strongly with HLE with the most potent compounds having k(obs)/[I] = 6900 M-1 s-1. However, substituents at this position had a marked effect on in vivo activity. The greatest oral activity in the lung hemorrhage assay was achieved with C-4 aryl carboxylic acid ethers (60-85% inhibition at 30 mg/kg po). Based upon the established mechanism of inhibition by these compounds, the C-4 substituent would be released, and therefore, the pharmacological potential of these C-4 substituents was of considerable concern. Fortunately, compounds containing 4-hydroxybenzoic acid and 4-hydroxyphenylacetic acid ethers at C-4 were among the most active analogs. These phenolic acids are also found as urinary metabolites in healthy humans. Other heteroaryls at C-4 were also orally active in this model despite relatively modest enzyme activity.

Dihydropyrancarboxamides related to zanamivir: a new series of inhibitors of influenza virus sialidases. 1. Discovery, synthesis, biological activity, and structure-activity relationships of 4-guanidino- and 4-amino-4H-pyran-6-carboxamides.

4-Amino- and 4-guanidino-4H-pyran-6-carboxamides 4 and 5 related to zanamivir (GG167) are a new class of inhibitors of influenza virus sialidases. Structure--activity studies reveal that, in general, secondary amides are weak inhibitors of both influenza A and B viral sialidases. However, tertiary amides, which contain one or more small alkyl groups, show much greater inhibitory activity, particularly against the influenza A virus enzyme. The sialidase inhibitory activities of these compounds correlate well with their in vitro antiviral efficacy, and several of the most potent analogues displayed useful antiviral activity in vivo when evaluated in a mouse model of influenza A virus infection. Carboxamides which were highly active sialidase inhibitors in vitro also showed good antiviral activity in the mouse efficacy model of influenza A infection when administered intranasally but displayed modest activity when delivered by the intraperitoneal route.

Maroteaux-Lamy syndrome, mild form--MPS vi b.

Mucopolysaccharidosis VI (Maroteaux-Lamy Syndrome) form B is a rare disease occurring in siblings. It may present with radiological features like Perthes' disease or hypothyroidism. We report two such cases, and discuss the differential diagnosis of the spondylo-epiphyseal dysplasias. We stress the importance of final diagnosis by identifying a particular glycosaminoglycan excess in the urine and an enzyme deficiency in the fibroblasts aryl sulphatase B and N-acetylgalactosamine-4-sulphatase.

Public honour, private shame and HIV: issues affecting sexual health service delivery in London's South Asian communities.

Within a wider discussion of health service provision for black and minority ethnic (BME) groups, this paper considers how socio-cultural factors affect the provision of HIV and sexual health services to South Asians in London. It argues that communally held concepts of honour and shame within South Asian communities create a framework of social control with significant implications for HIV/AIDS transmission. It examines the provision of culturally sensitive services to BME communities by ethnically specific and generic service providers through a case study of the Naz Project London. Finally, it proposes an agenda for future research into BME sexual health service provision.

Enzymic detection of metachromatic leukodystrophy patients and heterozygotes.

Two unrelated families with metachromatic leukodystrophy have been examined for the leukocyte enzyme arylsufatase A. The enzyme activities clearly reflect an autosomal recessive mode of inherence. All four parents showed heterozygote enzyme levels 40-60 percent of the control range while the two affected children had less than 20 percent normal activity. The two sibs of one affected child were shown to be heterozygote carriers. A simple screening method for sulfatase activity in tears has been developed which distinguished between metachromatic leukodystrophy patients and a control population which included other neurological disorders. Enzyme screening on tears may also be used to detect other lysosomal storage diseases including Tay-Sachs and Fabry disease.

Rett syndrome: case reports and review.

Rett syndrome consists of a progressive encephalopathy and psychomotor deterioration in young females who have appeared clinically normal until between six and eighteen months of age. The syndrome has incidence similar to that of phenylketonuria and autism in females. It has been widely recognised only since 1983. After six months of age head growth decelerates associated eventually with severe dementia, and autism, apraxia, stereotypic "hand washing" movements and loss of previously acquired skills occurs. Supportive symptoms may include breathing dysfunction, seizures, EEG abnormalities, and growth retardation. Occurrence indicates sporadic new mutations as a cause. The case histories of two patients diagnosed in New Zealand are described.

Bottom-up nutrient and top-down fish impacts on insect-mediated mercury flux from aquatic ecosystems.

Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting the health of wildlife and humans. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. The authors used experimental mesocosms to test the hypothesis that insect emergence and the associated flux of MeHg from aquatic to terrestrial ecosystems is affected by both bottom-up nutrient effects and top-down fish consumer effects. In the present study, nutrient addition led to an increase in MeHg flux primarily by enhancing the biomass of emerging insects whose tissues were contaminated with MeHg, whereas fish decreased MeHg flux primarily by reducing the biomass of emerging insects. Furthermore, the authors found that these factors are interdependent such that the effects of nutrients are more pronounced when fish are absent, and the effects of fish are more pronounced when nutrient concentrations are high. The present study is the first to demonstrate that the flux of MeHg from aquatic to terrestrial ecosystems is strongly enhanced by bottom-up nutrient effects and diminished by top-down consumer effects.