A model for the bioaccumulation of (99)Tc in lobsters (Homarus gammarus) from the West Cumbrian coast.

A biokinetic model is presented that simulates the uptake and release of (99)Tc by the European lobster (Homarus gammarus). This organism is of significant radioecological interest since lobsters, in contrast to most other organisms, have a high affinity for (99)Tc. The model is designed to represent annually averaged (99)Tc concentrations in lobsters from the Cumbrian coast, where significant levels of (99)Tc have been released under authorisation by the nuclear fuel reprocessing plant at BNFL Sellafield. This paper describes the construction of the model, how it was calibrated using data from published literature, and preliminary results indicating that model output agrees well with the available monitoring data. Given that this model successfully combines laboratory and field data, this research could potentially make a significant contribution to the field, as, to date, it has been difficult to predict and explain concentrations of (99)Tc in lobsters.

beta-Hydroxybutyrate in developing nauplii of brine shrimp (Artemia franciscana K.) under feeding and non-feeding conditions.

Body content of beta-hydroxybutyrate, and individual dry mass, carbon content, and survival rate, were studied in developing nauplii of the brine shrimp Artemia franciscana K. from hatching to 96-97 h post hatching at 27 +/- 1 degrees C. The effect of two diets was studied in the experiment: Super Selco (SS) with a high lipid content; and Protein Selco (PS) with a high protein content. A starving group (S) was used as reference. The level of beta-hydroxybutyrate at hatching was 0.6 nmol.ind-1; it increased to 1.0-1.5 nmol.ind-1 in the SS- and S-groups, while in the PS-group it remained stable between 0.6-0.8 nmol.ind-1. At 60-80 h post hatch in the SS- and S-groups, the levels of beta-hydroxybutyrate were similar to the initial levels. The survival rate remained higher than 95% until 24 h post hatching in all groups. At the end of the experiment, the survival rate was 63% in the PS-group, 13% in the S-group and 3% in the SS-group. The Artemia nauplii individual dry mass and carbon content remained relatively stable in the SS-group; both parameters showed a significant increase in the PS-group and a significant decrease in the S-group. The results suggest that Artemia nauplii utilise ketone bodies as a fuel during development and growth, but that ketone catabolism may be overloaded by excessive lipid feeding resulting in increased mortality and possibly a ketotic acidosis.

Implementation of substance use screening in prenatal clinics.

BACKGROUND AND OBJECTIVES: To reduce women's consumption of alcohol and other drugs during pregnancy, the Department of Epidemiology for the Aberdeen Area Indian Health Service (AAIHS) promoted a maternal substance use screening program for prenatal clinics in 1992. This report describes the adherence to the screening protocol at AAIHS facilities and barriers to such screening. METHODS: Prenatal clinic staff members at 20 AAIHS health care facilities were surveyed to determine the extent of prenatal substance use screening and the barriers to its implementation. The medical records of a random sample of 235 women who sought prenatal care at five hospitals were reviewed to determine whether prenatal clinic staff adhered to the screening protocol. RESULTS: Of the 20 health care facilities, 13 (65%) had implemented the screening. The major barriers to implementing screening were lack of training in prenatal substance use screening and lack of clinic staff designated to administer the screening protocol. Though not statistically significant, our data suggest that women not administered the screening questionnaire were more likely to be multiparous (prevalence ratio = 2.1; 95% confidence interval = 0.9, 4.5). CONCLUSIONS: To improve screening of pregnant women for substance use, prenatal clinic staff members should address administrative barriers and assess adherence of health care providers and patients to the screening protocol. Training of prenatal clinic personnel is essential to implement optimal maternal substance use screening in prenatal clinics.

Age-dependent accumulation of advanced glycation end-products in adult Drosophila melanogaster.

Advanced glycation end-product(s) (AGE) are formed in biological systems when reducing sugars react with amino groups on proteins. Long-lived proteins such as collagen and lens crystallins are known to be susceptible to AGE modification and may play a major role in the development of diabetes and other age-related pathologies. It has been previously suggested that AGE formation might affect the lifespan of experimental animals. Our study is the first to examine the effect of AGE accumulation on the life span of an organism, Drosophila melanogaster. We found that Drosophila melanogaster maintained at 24 degrees C accumulate significant AGE over their lifespan. Young flies (10 days old) had 44% less AGE than senescent flies (75 days old). We were able to reduce AGE accumulation in Drosophila melanogaster by raising the flies on a medium containing a known AGE inhibitor, aminoguanidine HCl. Reduction of AGE in flies failed to increase their mean lifespan, and high concentrations (40 mM) reduced the mean life span, which suggests that aminoguanidine is toxic at levels near those required for inhibition of AGE formation. However, the common fruit fly, Drosophila melanogaster, provides a simple model system to study the age-dependent accumulation of glycated proteins and their inhibition by novel compounds.

A morphological study of the gross and light microscopic lesions of infectious anaemia in Atlantic salmon (Salmo salar).

Infectious anaemia in Atlantic salmon (Salmo salar) was studied by recording gross and light microscopic changes, and the development of lesions was studied in relation to haematocrit values. Gross lesions were characterised by ascites formation, congestion and enlargement of liver and spleen, congestion of the foregut and petechiae in the peritoneum. Histologically, lesions were demonstrated in the liver, being characterised by congestion in early stages (that is, haematocrit values around 25), dilatation of the sinusoids, and in later stages (haematocrit values 25 to 15) formation of blood-filled spaces bearing morphological resemblance to peliosis hepatis. At low haematocrit values (around 10), these changes comprised large areas of the liver parenchyma, that is, blood-filled areas coalesced, presenting islets of degenerate and necrotic hepatocytes. At this stage, haemorrhagic necroses were found. Spleen and kidney lesions were characterised by congestion. In the foregut, congestion and bleeding in lamina propria were observed. Liver lesions became more disseminated and severe with decreasing haematocrit values. Hypoxia due to anaemia alone cannot fully explain the development of the liver lesions.