Baseline histopathological survey of a recently invading island population of 'killer shrimp', Dikerogammarus villosus.

Dikerogammarus villosus, an invasive amphipod, has recently been detected in UK freshwaters. To assess the potential for pathogen introduction with the invader, a year-long histopathology survey of the D. villosus population inhabiting the initial site of detection (Grafham Water, Cambridgeshire, UK) was conducted. Additional samples were collected from 2 other subsequently identified populations within the UK (Cardiff Bay and Norfolk Broads), and from established populations in France (River Rhine) and Poland (River Vistula). The data revealed a range of pathogens and commensals. Several pathogens occurring within continental populations were not present within the UK populations. Microsporidian parasites and a novel viral pathogen were amongst those not observed in the UK. The absence of these pathogens at UK sites may therefore impart significant survival advantages to D. villosus over native fauna, thereby increasing its success as an invader. The contrast in pathogen profile between UK and continental-invasive populations of D. villosus provides preliminary evidence for so-called 'enemy release' in UK populations of D. villosus and is suggestive of single-point introductions, rather than continual incursion events as previously observed throughout its continental invasive range. This baseline survey provides important data on the pathogen and commensal profile of a high-impact, invasive species early in its invasion history of the UK. It can be utilised to assess potential for temporal pathogen acquisition by non-native invasive aquatic species and to investigate competitive advantages placed upon this invader due to absence of important pathogens experienced within its native range.

Endocrine status and plasma lipids in inhabitants of the northern European part of the USSR.

Inhabitants of the northern districts of the Archangelsk Region of the USSR (Nenets and natives) were examined. Hormones of the hypophysis-adrenal cortex-thyroid gland system as well as the metabolites of lipid exchange were measured during the year. Higher mean levels of TSH and T3 were found in Nenets compared to natives. Activation of the hypophysis-thyroid gland system was demonstrated in the winter period compared to the summer one. Metabolites involved in lipid exchange transport in blood remained stable in Nenets, while natives showed dynamics of the lipid exchange metabolites related to the different seasons of the year.

Dynamics of hormone and metabolic state in polar inhabitants depend on daylight duration.

Fluctuations in the level of TSH, T3, T4 and total cholesterol were determined in male aborigines and native polar inhabitants in different photoperiods of the year. It was found that a rise of serum TSH and T3 and a reduction of the thyroxine level and total cholesterol occurred in both population groups with the lengthening of daylight duration. However, the amplitude of annual fluctuations in the studied variables was different. There was a significant correlation between TSH, T4 and T3 levels and daylight duration. The photoperiodical contrasts of the polar regions are probably important in the formation of the annual fluctuations of hormone levels of the hypophysis-thyroid gland system and total cholesterol.

Blood serum analyses in population studies: parallel analyses and degree of agreement in a Norwegian-Russian co-project. The Svalbard Study.

In a survey of more than 300 russian coal workers living on Svalbard, parallel laboratory analyses of gamma-glutamyltransferase, serum total cholesterol, high density lipoprotein, and triglycerides were performed in Tromsö, Norway and in Archangelsk, Russia. Mean values for gamma-glutamyltransferase and serum total cholesterol were significantly higher in Tromsö than in Archangelsk while mean values of triglycerides and high density lipoproteins were significantly lower in Tromsö than in Archangelsk. Linear regression plots revealed both systematical and arbitrary differences between the two laboratories. Because no "true" standards were available, we were unable to assess the accuracy of laboratory results. We conclude that laboratory measurements from Norway and Russia are not directly comparable. Future research programs between the two laboratories should attempt to include calibrated standards of test serum from which to identify sources of variation. Alternatively, the serum tests should always only be analyzed at one site.