Limited immunotoxic potential of technical formulation of the herbicide atrazine (AAtrex) in mice

Immunotoxicity of the technical atrazine formulation, AAtrex, was examined in C57B1/6 female mice following a sublethal exposure to equivalent 1/2–1.64 LD₅₀ doses of the herbicide. Animal weight was not affected by the herbicide exposure. No dose-related changes could be concluded for fluctuations in organ weight, changes in the spleen cell number and cell viability. Furthermore, cytofluorometric studies showed no significant changes in the frequency of L3T4-positive and Lyt-2-positive T-cells. Functional in vitro assays of mitogen activation showed no marked effects of AAtrex exposure on lymphocyte stimulation by lipopolysaccharide (LPS), phytohemagglutinin (PHA) and concanavalin A (Con-A). In addition, sublethal exposure to AAtrex did not affect interleukin-2 (IL-2) production by splenic cells. Furthermore, no doserelated effect could be concluded from a transient suppression of a primary humoral IgM response to sheep erythrocytes (SRBC) as well as from a transient inhibition of a specific T-cell response to alloantigens in mixed lymphocyte reaction (MLR). Exposure to equiv. 1/2−1/16 LD₅₀ doses augmented phagocytic activity of peritoneal macrophages, without any visible AAtrex dose-related effect. Normal humoral and cellular responses were restored at 14–40 days after the herbicide exposure. Overall, transient and reversible immunosuppression of humoral-mediated and cell-mediated responses and activated macrophage phagocytic activity could not be attributed to the direct chemical-related effect of sublethal exposure to AAtrex.     

Associations between seasonal variations in day length (photoperiod), sleep timing, sleep quality and mood: a comparison between Ghana (5°) and Norway (69°)

The hypothesis of whether day length (photoperiod) is an important zeitgeber (time‐giver) for keeping the circadian rhythm entrained to a 24‐hour cycle was examined, as was its association with sleep patterns and mood problems. Data were collected prospectively from a site with very large differences in daylight duration across seasons (Tromsø in Norway, 69°39′N) and a site with very small seasonal differences in daylight duration (Ghana in Accra, 5°32′N). Two hundred subjects were recruited from both sites in January. At the follow‐up in August, 180 and 150 subjects in Ghana and Norway participated, respectively. Use of a weekly sleep diary indicated low to moderately strong seasonal changes in rise‐ and bedtime, sleep efficiency and sleep onset latency only in the northern latitude. No seasonal changes in sleep duration or night awakenings were observed. The self‐report measures indicated moderate to strong seasonal differences in insomnia and fatigue, and weaker differences in depressed mood in Norway, but small to non‐existing seasonal differences in Ghana. Lack of daylight was related to phase‐delayed rise‐ and bedtimes, increased problems falling asleep, daytime fatigue and depressive mood. However, total sleep duration and sleep quality appeared unaffected.     

Bloodstream infections in head and neck cancer patients after curative-intent radiotherapy: a population-based study from the Danish Head and Neck Cancer Group database

Background Patients with head and neck squamous cell carcinoma (HNSCC) undergoing radiotherapy (RT) or chemoradiation (CRT) may become immunocompromised. In this population-based study, we aimed to investigate the risk factors, microbiological aetiologies, prognosis and impact on early non-cancer mortality of bloodstream infections (BSIs) after RT/CRT.Methods Patients with HNSCC of the pharynx, larynx and oral cavity treated with curative-intent RT/CRT in Denmark between 2010 and 2017 and subsequent BSI episodes occurring within 18 months of RT/CRT initiation were identified in national registries.Results We included 5674 patients and observed 238 BSIs. Increasing age, stage and performance status were significantly associated with an elevated BSI risk, while sex, smoking and high-grade mucositis were not. Human papillomavirus-positive oropharyngeal cancer patients had a decreased risk. Staphylococcus aureus accounted for 34% of episodes occurring during the first 3 months. The 30-day post-BSI mortality rate was 26% (95% confidence interval: 19–32) and BSIs were involved in 10% of early non-cancer deaths.Conclusion The risk of BSI development is associated with several patient- and disease-related factors and BSIs contribute considerably to early non-cancer mortality. Empiric antibiotic treatment regimens should prioritise coverage for S. aureus when treating suspected systemic infection in this population.Subject terms: Head and neck cancer, Cancer epidemiology     

Cancer in Greenlandic Inuit 1973-1997: a cohort study

The increasing westernization of the Arctic countries may influence the very particular cancer profile of these populations. Our objective was to investigate the development in cancer incidence from 1973 to 1997 in a large and well-defined Inuit population in Greenland. Greenland is part of the Danish Kingdom, and population statistics covering both countries are available from the same registry resource. Data from the Danish Civil Registration System and from the Danish Cancer Registry were used to calculate age-standardized cancer incidence rates for the periods 1973-1987 and 1988-1997 for persons born in Greenland. Using rates for Denmark, sex-specific standardized incidence ratios (SIRs) for 1988-1997 were calculated. Furthermore, age- and sex-specific incidence rates in the 2 periods were calculated for selected cancers. Total cancer incidence increased from 248.5 to 277.9 per 100,000 person-years in men and from 269.4 to 302.2 per 100,000 person-years in women. The incidence of lung, stomach, breast and colon cancer increased, whereas the incidence of cervical cancer decreased. Compared to the Caucasian population in Denmark, high SIRs were found for cancers of the nasopharynx, salivary gland, esophagus, stomach and cervix and low SIRs for testis, bladder, prostate, breast and hematologic cancers. Overall cancer incidence among Greenlandic Inuit is increasing as a result of increases in several cancers that are common in Western populations. A significant increase in the incidence of stomach cancer in both sexes, which contrasts global trends for this cancer, warrants further investigation.     

A population-based registry study of infant mortality in the Arctic: Greenland and Denmark, 1973-1997

OBJECTIVES: We sought to determine precise estimates of infant mortality rates and to describe overall trends in infant mortality in Greenland and Denmark from 1973 to 1997. METHODS: We analyzed data from population-based registries of all live-born infants in Greenland and Denmark to calculate infant mortality rates from 1973 to 1997. RESULTS: Between the periods of 1973-1977 and 1993-1997, neonatal mortality rates in Greenland declined from 20.9 per 1000 live-born infants to 15.7, and postneonatal mortality rates declined from 20.9 per 1000 to 5.9. Infant mortality rates were significantly higher in Greenland than in Denmark, and the excess mortality was uniformly distributed over all birthweight percentiles. In Greenland, the risk of infant death was significantly lower if the mother was born outside Greenland. CONCLUSIONS: Postneonatal mortality rates in Greenland have decreased significantly during the past 25 years, but little progress has been made in decreasing neonatal mortality rates. Disparities exist among children with different maternal origins.     

Metal artefact reduction for accurate tumour delineation in radiotherapy

Background and purpose

Two techniques for metal artefact reduction for computed tomography were studied in order to identify their impact on tumour delineation in radiotherapy.

Sleep patterns and insomnia in a large population‐based study of middle‐aged and older adults: The Tromsø study 2015–2016

Epidemiological studies assessing adult sleep duration have yielded inconsistent findings and there are still large variations in estimation of insomnia prevalence according to the most recent diagnostic criteria. Our objective was to describe sleep patterns in a large population of middle‐aged and older adults, by employing accurate measures of both sleep duration and insomnia. Data stem from the Tromsø Study (2015–2016), an ongoing population‐based study in northern Norway comprising citizens aged 40 years and older (n = 21,083, attendance = 64.7%). Sleep parameters were reported separately for weekdays and weekends and included bedtime, rise time, sleep latency and total sleep time. Insomnia was defined according to recent diagnostic criteria (International Classification of Sleep Disorders; ICSD‐3). The results show that 20% (95% confidence interval,19.4–20.6) fulfilled the inclusion criteria for insomnia. The prevalence was especially high among women (25%), for whom the prevalence also increased with age. For men, the prevalence was around 15% across all age groups. In all, 42% of the women reported sleeping <7 hr (mean sleep duration of 7:07 hr), whereas the corresponding proportion among males was 52% (mean sleep duration of 6:55 hr). We conclude that the proportion of middle‐aged and older adults not getting the recommended amount of sleep is worryingly high, as is also the observed prevalence of insomnia. This warrants attention as a public health problem in this population.