Nematode community structure as a bioindicator in environmental monitoring

Four of every five multicellular animals on the planet are nematodes. They occupy any niche that provides an available source of organic carbon in marine, freshwater and terrestrial environments. Nematodes vary in sensitivity to pollutants and environmental disturbance. Recent development of indices that integrate the responses of different taxa and trophic groups to perturbation provides a powerful basis for analysis of faunal assemblages in soil as in situ environmental assessment systems.

Fatty acid composition and dynamics of selected fungal-feeding nematodes and fungi

Fatty acid profiles of fungal-feeding nematodes, Aphelenchus avenae and Aphelenchoides composticola, and selected fungi were determined in microcosm cultures of agar, broth, or sand amended with organic matter. Fatty acids of A. avenae and A. composticola included 16:0 18:0, 18:1omega7, 18:1omega9, 18:2, 20:0, 20:1, 20:2, 20:3 and 20:4 phospholipid fatty acids (PLFAs) and neutral lipid fatty acids (NLFAs). The nematodes differed in relative amounts of saturated and C(18) fatty acids. Similar C(16) and C(18) PLFAs and whole-cell fatty acids were found in Rhizoctonia solani, Fusarium oxysporum and Trichoderma sp. with 18:2omega6 as the major component. The C(20) fatty acids were not found in these fungi. Although only present in the nematodes, C(20) PLFAs were only detected when nematode population levels were > or =22 per gram of sand, suggesting that there is a detection threshold that might limit their use as biomarkers in the soil community. After removal of nematodes from a food source, the relative amount of C(20) PLFAs (structural components of nematode cell membranes) decreased more slowly than the C(16) and C(18) PLFAs, which may have reflected ingested fungal cytoplasm in the nematode intestine. In the early stage of organic matter decomposition, total and fungal PLFAs were lower in the presence of A. composticola then in its absence at C:N ratios > or =30:1.

Trends in hip fracture care in the Republic of Ireland from 2013 to 2018: results from the Irish Hip Fracture Database

Hip fractures continue to be one of the most serious and costly injuries suffered by older people globally. This paper describes the development of a national hip fracture audit and summarises the first 6 years of data from the Republic of Ireland. This can help inform care, standards and outcomes of hip fracture patients.

INTRODUCTION

Ireland has one of the highest standardised rates of hip fracture in the world behind northern European countries. The Irish Hip Fracture Database (IHFD) was established in 2012 to drive clinical and organisational improvements in quality and effectiveness of hip fracture care. This paper describes the progression of the IHFD between 2013 and 2018 and identifies trends and areas for improvement.

METHODS

The IHFD is a clinically led, web-based audit, with data collected through the national Hospital Inpatient Enquiry (HIPE) electronic system, the principal source of information from publicly funded acute hospitals in Ireland. Eligible cases are aged ≥ 60 years with hip fracture as defined by IHFD or with other specified hip fracture excluding periprosthetic fractures. As of 2015, all 16 trauma-receiving hospitals within Ireland submitted data. Demographics and adherence to six national quality standards are described.

RESULTS

A total of 17,983 cases were included in the analysis. National coverage has increased from 63% in 2013 to 99% in 2018. Demographic characteristics are unchanged, but higher levels of comorbidity are seen. Internal fixation and hemiarthroplasty are the most common modes of surgical repair with two-thirds of cases receiving spinal rather than general anaesthesia. Increasingly patients are being assessed by a geriatrician (11% in 2013 to 69% in 2018) and receive a bone health assessment (65% in 2013 to 84% in 2018).

CONCLUSION

While some hip fracture standards have improved, further improvements are required to compare favourably internationally. Reduction of surgical delay and ensuring early mobilisation post-operatively are immediate priorities for the IHFD.

Cost of hospitalisation for hip fracture-findings from the Irish hip fracture database

The authors utilised the Irish Hip Fracture Database (IHFD) to quantify the impact of hip fracture on the health service in terms of incidence, bed days and financial costs. The absolute number of hip fracture cases recorded by the IHFD has increased, as has the associated costs of hospitalisation.

INTRODUCTION

Hip fracture places a considerable clinical and financial burden on the healthcare system, with acute hospitalisation accounting for a substantial proportion of the costs incurred. This paper aimed to quantify the cost of hospitalisation for hip fracture in Ireland in terms of bed days and direct hospital costs.

METHODS

The authors analysed 23,494 cases in the Irish Hip Fracture Database (IHFD) from 2014 to 2020. Case numbers and length of stay were analysed annually. Hospital costs for hip fracture were described using the 2020 Activity-Based Funding Price List, which outlines the fees paid to public hospitals for inpatient activity.

RESULTS

For the time period 2014-2020, the total cost of hospitalisation for hip fracture was approximately €296 million, equating to approximately €11,700 per episode of care. The annual cost of hospitalisation increased from approximately €34 million in 2014 to €44 million in 2020. In 2020, the mean length of stay for hip fracture was 17 days accounting for > 62,600 acute hospital bed days.

CONCLUSION

The absolute number of hip fracture cases recorded by the IHFD has increased, as has the cost of hospitalisation. Given the current capacity issues and economic constraints, there is a growing need to prioritise time spent in the most expensive acute hospital setting to the immediate perioperative period and maximise the use of community services and early supportive discharge for the rehabilitation phase.

Nematode-trapping fungi in organic and conventional cropping systems

ABSTRACT Nematode-trapping fungi, nematodes, and microbial biomass were quantified in conventionally and organically managed field plots in the Sustainable Agriculture Farming Systems Project at the University of California at Davis. There were four replicate plots (0.135 ha per plot) for each management system, and plots were sampled three times each year for 2 years. The hypothesis that nematode-trapping fungi would be more abundant in organically managed plots was partially supported: the number of species of nematode-trapping fungi was slightly but significantly greater in organic than in conventional plots, two species (Arthrobotrys dactyloides and Nematoctonus leiosporus) were detected more frequently in organic plots, and the population densities of A. dactyloides and N. leiosporus were greater in organic than in conventional plots. Two other species (A. haptotyla and A. thaumasia), however, tended to be more numerous in conventional than in organic plots, and the total density of nematode-trapping fungi was similar in organic and conventional plots. Bacterivorous nematodes were more abundant and microbial biomass (substrate-induced respiration) was greater in organic than in conventional plots. Suppression of the root-knot nematode Meloidogyne javanica, as measured in a bioassay, was not related to management system or population density of nematode-trapping fungi but was positively related to microbial biomass.

Neutrophil Enzyme Myeloperoxidase Modulates Neuronal Response in a Model of Subarachnoid Hemorrhage by Venous Injury

[Figure: see text].

Sensitivity of Meloidogyne javanica and Tylenchulus semipenetrans to Isothiocyanates in Laboratory Assays

ABSTRACT Isothiocyanates are released through enzymatic degradation of glucosinolates produced by plants in the family Brassicaceae. Glucosinolate profiles differ among plant species and the isothiocyanate derivatives differ in their toxicity to nematodes. Control of plant-parasitic nematodes in soil by isothiocyanates released from incorporated brassicaceous plant material has been inconsistent. Success might be improved with knowledge of the relative toxicities of various isothiocyanates against nematodes. Laboratory assays were conducted to determine lethal concentration (LC) values in sand of seven commercially available isothiocyanates against Tylenchulus semipenetrans and Meloidogyne javanica. The LC(90) values were 0.01 and 0.03 mumol/ml for 2-phenylethyl isothiocyanate and 0.48 and 0.35 mumol/ml for phenyl isothiocyanate for T. semipenetrans and M. javanica, respectively. Brassicaceous sources of benzyl or 2-phenylethyl isothiocyanate and, to a lesser extent allyl isothiocyanate, are the most promising candidates for plant-parasitic nematode management. The broader context of this research is the development of approaches for consistent and reliable use of plant-derived chemicals for nematode management. The strategy is to select plants in the family Brassicaceae based on their glucosinolate profiles and the sensitivity of the target nematode species to the associated isothiocyanates.

Comparative demography of isogenic populations of Caenorhabditis elegans

Demographic characteristics of the bacterial-feeding nematode Caenorhabditis elegans were determined in two long-lived mutant strains, TJ1052 (age-1), CB4876 (clk-1), and a wild-type strain, N2. Within each strain, there was little correlation between longevity and reproduction for individuals that lived longer than 10days. Long-lived mutant strains produced fewer eggs than the wild type. Mean total life spans were 13.2days for the wild type, 21.9days for age-1, and 15.8days for clk-1; maximum life spans were 24days for the wild type, 47days for age-1, and 32days for clk-1. Differences in total life span resulted primarily from longer post-reproductive survival. The mean post-reproductive life spans were longer than the wild type by 183% in age-1 and 60% in clk-1. We conclude that (i) post-reproductive survival is not correlated with egg production within isogenic populations of C. elegans, and (ii) the relationship between reproduction and longevity differs among isogenic populations with specific longevity genes.

Density-dependent parasitism of the soil-borne nematodeCriconemella xenoplax by the nematophagous fungusHirsutella rhossiliensis

Spatial sampling was used to investigate temporal density-dependent parasitism of the plant-parasitic nematodeCriconemella xenoplax byHirsutella rhossiliensis in three peach orchards on eight sample dates. The patches of soil in which the nematode and fungus interacted were assumed to possess similar density-dependent dynamics and to be small, independent, and asynchronous. Furthermore, sampling of separate patches was assumed to provide similar information with respect to density dependence as would temporal (repeated) sampling of the same patch. Percent parasitism was dependent on the number ofC. xenoplax/100 cm(3) soil (P=0.0001). The slope was unaffected by orchard or date but ranged from 0.0001 to 0.0043 depending on distance from the irrigation furrow. The relative shallowness of the slope and the large variation in percent parasitism not explained by nematode density suggest thatH. rhossiliensis is a weak regulator ofC. xenoplax population density.

Decline in the incidence of late diagnosed congenital dislocation of the hip

INTRODUCTION

We reviewed the incidence of early and late diagnosed CDH over a 13 yr period in a single maternity with a well established follow-up program and a stable population base. In March 1991, all newborn infants were nursed in the lateral or supine position, having previously been nursed prone. In addition, a dedicated hip screener was appointed in October 1992. We wished to determine whether these changes could have led to a reduction in late diagnosed CDH.

METHODS

Babies with suspected CDH were seen by a single consultant orthopaedic surgeon within 1 week of birth. Splints were not applied until diagnosis was confirmed by the orthopaedic surgeon. The study period was from January 1983 to December 1995, inclusive.

RESULTS

37,383 babies were born during the study period, an average of 2,876 births per annum. The average rate of babies referred to the orthopaedic surgeon was 12.8 per 1,000 (range 5.5-28.2 per 1,000). The average incidence of babies splinted early was 7.19 per 1,000 (range 4.0-14.1 per 1,000) with no discernible increase or decrease over the yrs. In contrast, there was a clear reduction in the incidence of late diagnosed CDH; 42/24,713 births (January 1983-February 1992) compared to only 2/12,673 births (March 1992-December 1995; p < 0.0001. Twelve of the 44 infants (27 per cent) diagnosed with late diagnosed CDH were discovered by the policy of routine hip radiographs at 6 months of age of all babies born by breech presentation (2/12) or those with a positive family history of CDH in a first degree relative (10/12). Six others had a diagnosis of CDH confirmed by X-rays done at 6 months of age because of doubts about their examination in the newborn period.

CONCLUSIONS

Nursing infants in the supine or lateral position and the introduction of a single hip screener were associated with a reduction in the incidence of late diagnosed CDH. Routine hip radiographs of high risk infants at 6 months of age proved to be a valuable safety net in detecting a significant proportion of previously undetected infants with CDH.

Development and testing of an assay for soil ecosystem health using the bacterial-feeding nematode Cruznema tripartitum

Survival and respiration rates of the bacterial-feeding nematode Cruznema tripartitum after incubation in soil for 48 hr provided a useful bioassay of the presence and concentration level of biologically active toxicants. The assay provided an indication of toxicant activity at sublethal levels, and a means of determining when the toxicant had declined to levels not deleterious to physiological function. Assays of soil contaminants based on the community structure of resident soil nematodes were more useful in undisturbed soils than in agricultural soils where the range of taxa was relatively narrow. Assays involving measurement of survival and respiration rates of nematodes after immersion in an aqueous extract of contaminated soils were not useful due to degradation and loss of contaminant during the extraction process.

Discharge destination after hip fracture: findings from the Irish hip fracture database

PURPOSE

Although home continues to be the place from which the majority of patients are admitted, less than one third of patients are Discharged Directly Home (DDH) following hip fracture. Once ready for discharge, DDH as opposed to Discharge to an Alternative Location (DAL), i.e., community care, rehabilitation facility or long-term care, is a high priority for patients and clinicians alike. Not only is DDH integral to the quality of life of patients, it is also an essential driver of the socioeconomic cost of hip fracture care.

METHODS

We analysed 21,819 cases in the Irish Hip Fracture Database from 2013 to 2019. Descriptive and analytical statistics were conducted.

RESULTS

29% (n = 6476) of patients were DDH during the study period. On multivariate analysis, the odds of DDH decreased as age increased (OR 0.28, p < 0.01, 95% CI 0.24-0.34). Patients who were independently mobile prior to fracture were 47% more likely to be DDH (OR 1.47, p < 0.01, 95% CI 1.29-1.68). Those mobilised early post operatively were 24% more likely to be DDH (OR 1.24, p < 0.01, 95% CI 1.06-1.45). Patients who waited > 72 h prior to surgery were 30% less likely to be DDH (OR 0.70, p < 0.01, 95% CI 0.56-0.88).

CONCLUSION

The authors identified patient characteristics that increased the likelihood of DDH, i.e., younger patients independently mobile prior to fracture, who received timely surgery and early post-operative mobilisation. The Irish Hip Fracture Standards (IHFS) incorporate 2 out the 3 modifiable factors identified, which reinforces the importance of the IHFS in improving patient outcomes.

Relationship between crop losses and initial population densities of Meloidogyne arenaria in winter-grown oriental melon in Korea

To determine the economic threshold level, oriental melon (Cucumis melo L. cv. Geumssaragi-euncheon) grafted on Shintozoa (Cucurbita maxima x Cu. moschata) was planted in plots (2 x 3 m) under a plastic film in February with a range of initial population densities (Pi) of Meloidogyne arenaria. The relationships of early, late, and total yield to Pi measured in September and January were adequately described by both linear regression and the Seinhorst damage model. Initial nematode densities in September in excess of 14 second-stage juveniles (J2)/100 cm(3) soil caused losses in total yields that exceeded the economic threshold and indicate the need for fosthiazate nematicide treatment at current costs. Differences in yield-loss relationships to Pi between early- and late-season harvests enhance the resolution of the management decision and suggest approaches for optimizing returns. Determination of population levels for advisory purposes can be based on assay samples taken several months before planting, which allows time for implementation of management procedures. We introduce (i) an amendment of the economic threshold definition to reflect efficacy of the nematode management procedure under consideration, and (ii) the concept of profit limit as the nematode population at which net returns from the system will become negative.

Response of Soybean to Heterodera glycines Races 1 and 2 in Different Soil Types

Experiments were conducted for 3 years at four locations and 1 year with six soil types at a common location in North Carolina to determine damage and control-cost functions for Heterodera glycines races 1 and 2 on soybean. In the experiments on native loamy sand and sandy soils, tolerance limits for initial population densities were 0 or very low, whereas in a muck, the tolerance limit was 315 eggs/500 cm(3) soil. The aggressive race 2 was more damaging than race 1 in Lakeland sand and Norfolk loamy sand. The crop response was not different between races in the Appling sandy clay loam and Belhaven muck. Soybean yield responses to H. glycines were linear in six soil types in microplots at a common site. The amount of damage varied among these soil types, with lowest yields in the muck because of severe drought stress in this soil. An exponential function adequately described soybean yield response relative to nematode control with increasing rates of aldicarb in Norfolk loamy sand. Treatment with aldicarb in the Lakeland sand decreased the effective egg population of H. glycines but had only a minor effect in the muck.

Plant Sources of Chinese Herbal Remedies: Effects on Pratylenchus vulnus and Meloidogyne javanica

More than 500 plant species, used alone or in combination, are documented in Chinese traditional medicine to have activity against helminth and micro-invertebrate pests of humans. We subjected 153 candidate medicines or their plant sources to multilevel screening for effectiveness against plant-parasitic nematodes. For extracts effective in preliminary screens, we determined time-course and concentration-response relationships. Seventy-three of the aqueous extracts of medicines or their plant sources killed either Meloidogyne javanica juveniles or Pratylenchus vulnus (mixed stages), or both, within a 24-hour exposure period. Of 64 remedies reported as antihelminthics, 36 were effective; of 21 classi- fied as purgatives, 13 killed the nematodes; of 29 indicated as generally effective against pests, 13 killed the nematodes. Sources of extracts effective against one or both species of plant-parasitic nematodes are either the whole plant or vegetative, storage or reproductive components of the plants. Effective plants include both annuals and perennials, range from grasses and herbs to woody trees, and represent 46 plant families.

Influence of Environmental Factors on the Hatch and Survival of Meloidogyne incognita

The influence of soil temperature and moisture on Meloidogyne incognita (Kofoid and White) Chitwood was examined in relation to hatching and survival of second-stage juveniles (J2). Nematodes were cultured on cotton (Gossypium hirsutum L. cv. Acala SJ2) under field conditions to provide populations similar to those found in the field in late autumn. Egg masses were placed in a temperature range (9-12 C and 21 C), and hatch was measured over a period equivalent to 20 degree days > 10 C (DD10). Hatch occurred below the reported 18 C activity threshold, was restricted below 12 C, and was inhibited below 10 C. Soil moisture influence on hatch was measured by placing egg masses in Hesperia sandy loam and subjecting them to suction pressures ranging from -1.1 bars to -4 .5 bars. Suction potentials of less than -2 bars reduced hatch and less than -3 bars inhibited hatch. J2 were placed in sandy loam soil with soil moisture near field capacity, and their motility was measured over a period of 500 DD10. In the absence of a host, more than 90% of J2 became nonmotile over this period.

Density-dependent nematode seasonal multiplication rates and overwinter survivorship: a critical point model

Nematode multiplication rates Pf/Pi and overwinter survivorship (Pi2/Pfl) for Meloidogyne incognita were both adequately described by negative exponential models, indicating density dependence in each case. Density dependence of the multiplication rates is mediated by resource limitation and host damage; in survivorship rates it may be mediated by limitation of stored reserves or prevalence of antagonists. Parameters of multiplication rate models were crop specific and varied with host status and environmental suitability. Maximum multiplication rates (a) of nearly 1,000 were measured for tomatoes. Equilibrium densities were sensitive to tolerance of the nematode by the crop. Overwinter survival rates varied among locations where cultural practices and length of infestation time differed.

Validation of a model for prediction of host damage by two nematode species

PLANT ROOTS WERE MECHANICALLY INJURED OR SUBJECTED TO NEMATODE PARASITISM TO TEST THE MODEL OF HOST DAMAGE BY TWO NEMATODE SPECIES: y = m' + (l - m')c'z(P)z(P) for y </= 1.0 and y = 1.0 for y > 1.0, where m' = m + (m - m) (1 - y)/[(1 - y) + (l - y)] and c' = (z(-T) + z(-T))/2. Damage functions for greenhouse-grown radish plants (cv. Cherry Belle) mechanically injured with small or large steel needles were used to predict growth of plants injured by both needles. Growth predictions accounted for 94%, 87%, and 82% of mean treatment variation in plant height, stem weight, and root weight, respectively. Cowpea (cv. California Blackeye No. 5) damage functions, based on preplant population levels of Meloidogyne incognita and M. javanica, were used to predict seed yield of plants concomitantly infected with various levels of each species. Single species damage functions and population growth curves indicated significant host resistance to M. incognita and significantly lower virulence of that species compared to M. javanica. Model predictions accounted for 88% of mean seed yield variation in two-species treatments. In a separate experiment, mean top weights of 30-day-old cowpea plants, nniformly inoculated with 20,000 M. javanica eggs, increased with increasing levels of concomitantly inoculated M. incognita eggs. It is speculated that competitive interactions between M. incognita and M. javanica mitigated host damage by the more virulent species.

Development of a computer-simulation model for a plant-nematode system

A computer-simulation model (MELSIM) of a Meloidogyne-grapevine system is developed. The objective is to attempt a holistic approach to the study of nematode population dynamics by using experimental data from controlled environmental conditions. A simulator with predictive ability would be useful in considering pest management alternatives and in teaching. Rates of flow and interaction between the components of the system are governed by environmental conditions. Equations for these rates are determined by fitting curves to data from controlled environment studies. Development of the model and trial simulations have revealed deficiencies in understanding of the system and identified areas where further research is necessary.