Vulnerability of Aquatic Insect Species to Insecticides, Depending on Their Flight Period and Adult Life Span

Effects of insecticides on terrestrial adult life stages of otherwise aquatic insects, such as mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera), are largely unknown. In the present study, a risk model was used to pinpoint the species most likely to experience effects due to spray drift exposure during the adult life stage. Using data from an earlier case study with lambda-cyhalothrin, 6 species with different life cycle traits were used to explore how life cycle characteristics may influence vulnerability. In addition, we performed a generic calculation of the potential effect on the terrestrial life stages of 53 species (including 47 species with unknown sensitivity). Our approach incorporated temporal and spatial distribution of both the insect and the insecticide, creating different exposure conditions among species due to variation in the relative proportion of the populations present at the time of insecticide spraying. The Ephemeroptera species represented were least vulnerable due to their extremely short adult life span and relatively short flight period. Based on their life cycle characteristics, Plecoptera and Trichoptera species were more vulnerable. These vulnerable species segregated into 2 distinct groups; one with a long adult life span to emergent period ratio and another with a high overlap between emergent period and spraying season. We therefore recommend that future ecotoxicological tests be done on species with these life cycle characteristics. Environ Toxicol Chem 2021;40:1778-1787. © 2021 SETAC.

Terrestrial adult stages of freshwater insects are sensitive to insecticides

Terrestrial adult stages of freshwater insects may be exposed to pesticides by wind drift, over-spray, contact or feeding. However, studies addressing insecticide effects on freshwater invertebrates focus primarily on the impact of pesticides reaching the streams and potentially harming the aquatic juvenile stages. This is also reflected in the current risk assessment procedures, which do not include testing of adult freshwater insects. In order to assess the potential impact of insecticides on adult stages of freshwater insects, we exposed six common species to the insecticides Karate (lambda-cyhalothrin) and Confidor (imidacloprid). Dose-response relations were established, and LD₅₀ estimates were compared to those of the honey bee, Apis mellifera L. (Hymenoptera: Apidae), which is the standard terrestrial test insect when pesticides are evaluated prior to commercial release. Generally, the tested species were more sensitive to the studied insecticides than the honey bee. In order to examine whether the sensitivity of adult stages of freshwater insects corresponds with the sensitivity of the juvenile stages of the same species, the ranking of the two life stages with respect to the toxicity of Karate was compared, revealing some correspondence, but also some dissimilarities. Our results strongly indicate that terrestrial adult stages of aquatic insects are not adequately protected by current risk assessment procedures.

Slow-release vaginal insert of misoprostol versus orally administrated solution of misoprostol for the induction of labour in primiparous term pregnant women: a randomised controlled trial

OBJECTIVE

To compare the World Health Organization (WHO) recommended orally administrated dosage of misoprostol (25 μg) with a vaginal slow-release (7 μg/hour) insert of misoprostol regarding time from induction to delivery and safety of the method.

DESIGN

Open label, Randomised controlled trial (RCT).

SETTING

Delivery ward at a secondary referral hospital in Stockholm, Sweden, from 1 October 2016 to 21 February 2018.

POPULATION

One hundred and ninety-six primiparous women with singletons in cephalic presentation at ≥37 weeks of gestation and with a Bishop score of ≤4.

METHODS

Women were randomised to an oral solution of misoprostol (Cytotec^® n = 99) or vaginal slow-release misoprostol (Misodel^® [MVI] n = 97).

MAIN OUTCOME MEASURES

Primary outcome: time from induction to vaginal delivery.

SECONDARY OUTCOMES

mode of delivery; proportion of vaginal deliveries within 24 hours (VD24); neonates with an Apgar score of <7 at 5 minutes; pH < 7.10; postpartum haemorrhage (PPH) of >1000 ml; hyperstimulation; and women's delivery experience (VAS).

RESULTS

There was no difference in the time to delivery [corrected] (median 21.1 hours in the MVI group and 23.2 hours in the oral group; Kaplan-Mayer log rank P = 0.31). There was no difference regarding the proportion of VD24 (50.5 versus 55.7%, P = 0.16). Hyperstimulation with non-reassuring cardiotocography (CTG) was more common in the MVI group (14.4 versus 3.0%, P < 0.01). Terbutaline (Bricanyl^® ) was used more often for hyperstimulation in the MVI group (22.7 versus 4.0%, P < 0.01). There was no difference in the numbers of children admitted to the neonatal intensive care unit (NICU).

CONCLUSIONS

Vaginal delivery after induction of labour (IOL) with slow-release misoprostol did not result in a shorter time from induction to vaginal delivery, compared with oral misoprostol solution, but was associated with a higher risk for hyperstimulation and fetal distress. There were no differences in mode of delivery or neonatal outcome.

TWEETABLE ABSTRACT

IOL with MVI was similar to oral solution of misoprostol but hyperstimulation and fetal distress were more common.

Preoperative myocardial troponin T elevation is associated with the fracture type in patients with proximal femoral fracture

BACKGROUND AND AIMS

Cardiovascular complications are common in hip fracture patients but the role of fracture type and operative method in these is unclear. This prospective cohort study aimed to evaluate the impact of fracture- and operative characteristics on perioperative cardiovascular complications and prognosis in unselected hip fracture patients.

MATERIAL AND METHODS

During a 7-month trial registration period, a population of 197 consecutive hip fracture patients (median age 84 years) diagnosed with femoral neck or pertrochanteric fracture was formed. The exclusion criteria were patient refusal, subtrochanteric fracture, or death preoperatively. Pre- and postoperative troponin T (TnT) elevation, perioperative N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) level, perioperative cardiovascular adverse events, and all-cause 30-day and 2- and 5-year mortalities were studied.

RESULTS

Femoral neck fracture was independently associated with preoperative myocardial injury witnessed by TnT elevation (HR 2.95, 95% confidence interval 1.21-7.19, p = 0.018). The fracture type, surgery delay, or operative method were not significantly associated with NT-proBNP levels, cardiovascular adverse event diagnoses, or prognosis. Cardiovascular adverse events were clinically diagnosed in 28 (14%) participants, and these had a higher mortality compared to participants without such diagnosis (at 30 days, 32% vs 5%; 2 years, 71% vs 31%; and 5 years, 86% vs 59%; p < 0.001).

CONCLUSION

While the femoral neck fracture independently predicts preoperative cardiovascular morbidity, the operative method does not affect perioperative cardiovascular complications or the prognosis, and it may be selected by the treating clinician based on other criteria.

Is Erica tetralix abundance on wet heathlands controlled by nitrogen deposition or soil acidification?

Erica tetralix is the key species on NW European wet heathlands, where it is often found to be the dominating plant species. Consequently, it is of considerable concern that the species has decreased significantly in cover from 28% to 18% over a six-year period. In order to understand the underlying causes, a structural equation modeling (SEM) approach was applied on ecological data from 1130 wet heathland plots. Both atmospheric N deposition and soil acidification were included in the SEM. The most important causal effect revealed by the SEM was a significant negative effect of N deposition on the cover of E. tetralix, whereas soil acidity tended to have a negative effect of relatively less importance. There was no significant effect of N deposition on soil pH, which indicates that there are no major indirect effects of N deposition on the cover of E. tetralix mediated by soil acidification.

Evidence for acidification-driven ecosystem collapse of Danish Erica tetralix wet heathland

We report observations of disappearance of Erica tetralix in wet heathland, which is unlikely to be caused by competition, as E. tetralix is dying before its place is taken up by other species. To investigate the causes, we used both old and new data. Results showed that presence of Molinia caerulea and Calluna vulgaris were substantial in the former E. tetralix dominated areas. Measurements of the C/N ratio in the morlayer were between 21 and 26 under the E. tetralix stands. As the expected C/N ratio in a healthy nutrient poor ecosystem like the E. tetralix wet heathland is around 30, this indicates that the ratio is probably decreasing and, correspondingly, the probability of nitrogen leaching from the ecosystem is increasing. The morlayer pH was extremely low-between 3.03 and 3.78. This represents a pH decline since the 1960s, where pH values generally were above 4. This supports the hypothesis that the decrease in morlayer pH is the major factor explaining the disappearance of E. tetralix and that measures to increase pH should be considered as part of the recommendations for relevant future management.

Effects on hawthorn the year after simulated spray drift

This paper describes the effect of a herbicide applied at levels consistent with off target movement on hawthorn the year following exposure. In the experiment, metsulfuron-methyl was applied in five dosages to individual trees in seven different hawthorn hedgerows. Spraying was conducted both at the bud stage and at the early flowering. Five endpoints (i.e. leaves, buds, flowers, green berries and mature berries) were sampled and counted. All were significantly reduced with increasing exposure. Present day risk assessment of effects on non-target plants is therefore likely to overlook significant effects on perennial non-target plants in the spray drift zone due to the focus on results from short-term laboratory test studies. The significance of the present study is underlined by the fact that the effects observed were significant, even though other influential factors such as herbivory and differential pollination were not eliminated and that experiments were conducted in multiple locations.

Metsulfuron spray drift reduces fruit yield of hawthorn (Crataegus monogyna L.)

This study was carried out to investigate whether spray drift of metsulfuron has a potential to negatively affect hawthorn (Crataegus monogyna) hedgerows near agricultural fields. For this purpose four doses of metsulfuron ranging from 5% to 40% of the field dose (4 g metsulfuron per hectare) were sprayed on trees in seven different hawthorn hedgerows. The actual deposition on the leaves was measured by means of a tracer (glycine). Spraying was conducted both at the bud stage and at early flowering. Leaves, flowers, green berries and mature berries were harvested and the number and weight of each were measured. The spraying at the bud stage caused a highly significant reduction in number and dry weight of berries, whereas it had no effects on leaf and flower production. The berry reduction was close to 100% at actual depositions relevant for spray drift under normal conditions. Spraying at early flowering also significantly reduced berries although the effect was smaller than for the spraying at bud stage. The early flower stage spraying caused no reduction in number and size of leaves. The possible ecological consequence is that metsulfuron spray drift from agricultural fields has a potential to reduce the amount of berries available for frugivorous birds in nearby hedgerows. A potential need for regulatory measures to reduce herbicide spray drift to hedgerows situated near agricultural fields with herbicide use is also indicated.

Long-term trends in the uptake of radiocesium in Rozites caperatus

Measurements of (134)Cs and (137)Cs in Rozites caperatus from 1991 to 2001 showed differences in the uptake pattern of Chernobyl and fallout derived radiocesium over time. The effective half-life of Chernobyl derived (137)Cs was determined to 12.4 years, whereas fallout derived (137)Cs had an effective half-life of 9.8 years. However, the trend for Chernobyl derived (137)Cs was clearly not linear. An effective average half-life of 3.1 years was determined for Chernobyl derived (137)Cs in the period from 1991 to 1994. The corresponding ecological half-life was 3.4 years. In the period from 1994 to 2001 it is possible that the effective half-life was longer than the physical, which indicates that more Chernobyl cesium becomes available than disappears through radioactive decay. The difference may be due to depth distribution of radiocesium, i.e. fallout derived cesium have penetrated deeper than Chernobyl. The changes in the half-lives of Chernobyl derived radiocesium over time together with the half-life of the older fallout derived radiocesium may be valuable in predictions of future radiocesium concentrations in mushrooms and thereby of food chain transfer to man.

Effects of pendimethalin at lower trophic levels--a review

Pendimethalin's herbicidal action lies in its inhibition of the steps in plant cell division responsible for chromosome separation and cell wall formation. Terrestrial studies show that 10-20% of the herbicide evaporates during the first weeks after application. The remainder may dissipate biologically or chemically. Half-maximal dissipation time, or half-life (DT(50)) values vary from a few days to >200 days. Field and laboratory studies showed that reduced temperatures and drought prolong dissipation time to as long as 72-2094 days. In freshwater, pendimethalin concentrations reach 6 microg/L after runoff. In water the 10% lethal concentration (LC(10)) for Daphnia was 6 microg/L when exposed via suspended food. The LC(50) was 78 microg/L. An invertebrate field study showed that soil nematodes were reduced by 35-60% at pendimethalin application rates of 0.75 and 1.0 kg/ha, respectively. After application, soil microbiota is affected by pendimethalin for approximately 4 weeks. Plant-Rhizobium symbiosis is affected at application rates of 0.5-1.0 kg/ha.

Transoesophageal echocardiography in selecting patients for anticoagulation after ischaemic stroke or transient ischaemic attack

OBJECTIVES

To investigate prospectively the role of transoesophageal echocardiography (TEE) in selecting patients for anticoagulation in an unselected stroke population.

METHODS

Transthoracic echocardiography (TTE) and TEE were done in all clinically suitable hospitalised patients (n = 457) with transient ischaemic attack or ischaemic stroke in the acute phase during a two year period in Turku University Hospital. 441 patients were successfully evaluated for cardiac sources of embolism using TEE within 31 days of the event.

RESULTS

A major risk factor for a cardiac source of embolism excluding atrial fibrillation, acute myocardial infarction, and prosthetic valve was detected in 10% of patients and a minor risk factor for a cardiac source of embolism in 46%. When a major risk factor of a cardiac source of embolism was detected using TTE or TEE and no contraindications were present, the patient was given anticoagulation drugs. If a minor risk factor for a cardiac source of embolism was detected, anticoagulation treatment was started after clinical assessment, if no contraindications were present. In 62 (14%) cases, the patient was given oral anticoagulation drugs or the necessity of ongoing anticoagulation treatment was confirmed on the basis of TEE. When these anticoagulation treated patients were evaluated using logistic regression analysis, they were found to have significantly more atrial fibrillation and histories of myocardial infarctions. Moreover, the patients were mainly men. When patients in sinus rhythm and without any history of cardiac disease were analysed, 8% of patients were found to have been given anticoagulation drugs on the basis of TEE data.

CONCLUSION

This study suggests that TEE should be used in patients with stroke even without any clinical evidence of cardiac disease when the patients are candidates for anticoagulation.

Porcine neural xenografts in rats and mice: donor tissue development and characteristics of rejection

Embryonic ventral mesencephalic tissue from the pig is a potential alternative donor tissue for neural transplantation to Parkinson's disease patients. For stable graft survival, the host immune response has to be prevented. This study was performed in order to analyze the mechanisms and dynamics of neural xenograft rejection, as well as neurobiological properties of the donor tissue. Adult normal mice and rats, and cyclosporin A-treated rats, received intrastriatal transplants of dissociated embryonic ventral mesencephalic pig tissue that was 27 or 29 embryonic days of age (E27 and E29). The animals were perfused at 2, 4, 6, and 12 weeks after grafting and the brains were processed for immunohistochemistry of dopaminergic (tyrosine hydroxylase positive) neurons, CD4(+) and CD8(+) lymphocytes, natural killer cells, macrophages, microglia, and astrocytes. Thirty-five rats received daily injections of BrdU for 5 consecutive days at different time points after transplantation and were perfused at 6 weeks. These animals were analyzed for proliferation of cells in the donor tissue, both in healthy and in rejecting grafts. No tyrosine hydroxylase-positive cells proliferated after grafting. Our results demonstrated that E27 was superior to E29 donor tissue for neurobiological reasons. Cyclosporin A immunosuppression was protective only during the first weeks and failed to protect the grafts in a long-term perspective. Grafts in mice were invariably rejected between 2 and 4 weeks after transplantation, while occasional grafts in untreated rats survived up to 12 weeks without signs of an ongoing rejection process. CD8(+) lymphocytes and microglia cells are most likely important effector cells in the late, cyclosporin A-resistant rejection process.

Genotypes of clustered cases of Pneumocystis carinii pneumonia

Reports of outbreaks of Pneumocystis carinii pneumonia (PCP) among human immunodeficiency virus-negative immunocompromised patients have suggested a person-to-person transmission of P. carinii. In this study, 17 bronchoalveolar lavage isolates from patients in 3 PCP outbreaks were genotyped, 2 in renal transplant recipients and 1 outbreak among patients with haematological disorders. Genotypes in the P. carinii sp. f. hominis (P. carinii f.sp. hominis) mt large subunit ribosomal RNA site 85 were detected by 2 methods: direct sequencing and 3 different allele-specific polymerase chain reaction assays. Although limited data on patient contacts were available, the detected P. c. hominis genotypes do not support person-to-person transmission as the predominant transmission route of P. carinii in humans.

About the mutagenicity of chlorine-substituted furanones and halopropenals. A QSAR study using molecular orbital indices

Electron affinities, frontier molecular orbital energies and electron densities at individual carbon atoms were calculated for 11 chlorofuranones including the strong mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and for 5 halopropenals by semi-empirical AM1 and ab initio STO-3G methods. Significant correlations were found between Ames TA100 mutagenicity and the following AM1 electronic parameters of chlorofuranones: electron affinity (r = 0.9556). LUMO energy (r = 0.9332) and frontier electron density of LUMO at the alpha-carbon (r = 0.8882). In halopropenals only LUMO electron density at the beta-carbon correlates well with mutagenicity. The observed correlations suggest a reaction mechanism in which chlorofuranones and halopropenals act as electron acceptors in the interaction with DNA.

Comparison between surgeons and general practitioners with respect to cardiovascular and psychosocial risk factors among physicians

The incidence of mortality from ischemic heart disease in Sweden has been reported to be elevated for surgeons in comparisons with most other groups of physicians. The objective of the present investigation was to compare cardiovascular risk factors and psychosocial work characteristics of surgeons and general practitioners, the latter having a substantially lower rate of ischemic heart disease. A random sample of 36 male surgeons and 30 male general practitioners was selected. The results showed no clear-cut differences in physiological risk factors. Overall mental strain was greater among the surgeons, as was the inability to relax after work, perceived work tempo, and total number of workhours. There were significant associations between psychosocial work characteristics and traditional cardiovascular risk factors, and the study gives further support to the validity of using long-term glucose markers, such as fructosamine, as indicators of metabolic stress.