High Lipid Content of Prey Fish and n-3 PUFA Peroxidation Impair the Thiamine Status of Feeding-Migrating Atlantic Salmon (Salmo salar) and Is Reflected in Hepatic Biochemical Indices.

Signs of impaired thiamine (vitamin B1) status in feeding-migrating Atlantic salmon (Salmo salar) were studied in three Baltic Sea areas, which differ in the proportion and nutritional composition of prey fish sprat (Sprattus sprattus) and herring (Clupea harengus). The concentration of n-3 polyunsaturated fatty acids (n-3 PUFAs) increased in salmon with dietary lipids and n-3 PUFAs, and the hepatic peroxidation product malondialdehyde (MDA) concentration increased exponentially with increasing n-3 PUFA and docosahexaenoic acid (DHA, 22:6n-3) concentration, whereas hepatic total thiamine concentration, a sensitive indicator of thiamine status, decreased with the increase in both body lipid and n-3 PUFA or DHA concentration. The hepatic glucose 6-phosphate dehydrogenase activity was suppressed by high dietary lipids. In salmon muscle and in prey fish, the proportion of thiamine pyrophosphate increased, and that of free thiamine decreased, with increasing body lipid content or PUFAs, or merely DHA. The thiamine status of salmon was impaired mainly due to the peroxidation of n-3 PUFAs, whereas lipids as a source of metabolic energy had less effect. Organochlorines or general oxidative stress did not affect the thiamine status. The amount of lipids, and, specifically, their long-chain n-3 PUFAs, are thus responsible for generating thiamine deficiency, and not a prey fish species per se.

Fatty acid signatures connect thiamine deficiency with the diet of the Atlantic salmon (Salmo salar) feeding in the Baltic Sea.

Thiamine (vitamin B1) deficiency in salmonids related to a lipid-rich fish diet causes offspring mortality in the yolk-sac fry phase. A low free thiamine (THIAM) concentration in eggs is an indication of this syndrome. Thiamine deficiency of salmon (Salmo salar) feeding in the Baltic Sea, called M74, was connected to the principal prey fish and feeding area using fatty acid (FA) signature analysis. The FAs of feeding salmon from two areas of the Baltic Sea, the Baltic Proper (57°10' 19°30') and the Bothnian Sea (61°30' 20°00') in 2004, reflected the principal prey species in these areas, sprat (Sprattus sprattus) and herring (Clupea harengus), respectively. Arachidonic acid (ARA, 20:4n-6) and 18:1n-7 indicated dietary herring, 18:1n-9 dietary sprat and 14:0 feeding in the Baltic Proper. The muscle FA profile of non-M74 female spawners of the River Simojoki in a year (1998) with a moderate M74 incidence and salmon of a non-M74 year (2004) reflected herring FAs, whereas the FAs in the M74 year and specifically in M74 females displayed characteristics of sprat. In the M74 year, the THIAM concentration had the strongest positive correlation with the proportion of muscle ARA, and the strongest negative correlations with 14:0 and the ratios 18:1n-9/ARA and 14:0/ARA. Thus, ARA along with 14:0 and these ratios were the most sensitive FA indicators of the dietary species and origin of the M74 syndrome. Despite the pre-spawning fasting, tissue FA signatures were consequently able to connect dietary sprat in the Baltic Proper with thiamine deficiency in Baltic salmon.

Quality Management Framework for Total Diet Study centres in Europe.

A Quality Management Framework to improve quality and harmonization of Total Diet Study practices in Europe was developed within the TDS-Exposure Project. Seventeen processes were identified and hazards, Critical Control Points and associated preventive and corrective measures described. The Total Diet Study process was summarized in a flowchart divided into planning and practical (sample collection, preparation and analysis; risk assessment analysis and publication) phases. Standard Operating Procedures were developed and implemented in pilot studies in five organizations. The flowchart was used to develop a quality framework for Total Diet Studies that could be included in formal quality management systems. Pilot studies operated by four project partners were visited by project assessors who reviewed implementation of the proposed framework and identified areas that could be improved. The quality framework developed can be the starting point for any Total Diet Study centre and can be used within existing formal quality management approaches.

Development of harmonised food and sample lists for total diet studies in five European countries.

A total diet study (TDS) is a public health tool for determination of population dietary exposure to chemicals across the entire diet. TDSs have been performed in several countries but the comparability of data produced is limited. Harmonisation of the TDS methodology is therefore desirable and the development of comparable TDS food lists is considered essential to achieve the consistency between countries. The aim of this study is to develop and test the feasibility of a method for establishing harmonised TDS food and sample lists in five European countries with different consumption patterns (Czech Republic, Finland, Germany, Iceland and Portugal). The food lists were intended to be applicable for exposure assessment of wide range of chemical substances in adults (18-64 years) and the elderly (65-74 years). Food consumption data from recent dietary surveys measured on individuals served as the basis for this work. Since the national data from these five countries were not comparable, all foods were linked to the EFSA FoodEx2 classification and description system. The selection of foods for TDS was based on the weight of food consumed and was carried out separately for each FoodEx2 level 1 food group. Individual food approach was respected as much as possible when the TDS samples were defined. TDS food lists developed with this approach represented 94.7-98.7% of the national total diet weights. The overall number of TDS samples varied from 128 in Finland to 246 in Germany. The suggested method was successfully implemented in all five countries. Mapping of data to the EFSA FoodEx2 coding system was recognised as a crucial step in harmonisation of the developed TDS food lists.

Effect of aerobic fitness on the physiological stress responses at work.

OBJECTIVES: The aim of the present study was to examine the effects of aerobic fitness on physiological stress responses experienced by teachers during working hours. MATERIALS AND METHODS: Twenty-six healthy female and male teachers aged 33-62 years participated in the study. The ratings of perceived stress visual analogue scale (VAS), and the measurement of physiological responses (norepinephrine, epinephrine, cortisol, diastolic and systolic blood pressure, heart rate (HR), and trapezius muscle activity by electromyography (EMG), were determined. Predicted maximal oxygen uptake (VO(2)max) was measured using the submaximal bicycle ergometer test. The predicted VO(2)max was standardized for age using residuals of linear regression analyses. RESULTS: Static EMG activity, HR and VAS were associated with aerobic fitness in teachers. CONCLUSIONS: The results suggest that a higher level of aerobic fitness may reduce muscle tension, HR and perceived work stress in teachers.

Dynamic surface electromyographic responses in chronic low back pain treated by traditional bone setting and conventional physical therapy.

OBJECTIVE: This study compared the dynamic surface electromyographic (EMG) activities of back muscles and pain before and after traditional bone setting and physical therapy. METHODS: This study was a prospective clinical trial that compared surface EMG dynamic activities after traditional bone setting and physical therapy. Sixty-one patients (mean age, 41 years) with nonspecific low back pain were randomized into two subgroups by treatment. The patients underwent a dynamic EMG evaluation for which they were asked to stand and then bend forward as far as possible, stay fully flexed, and return to standing. A flexion-relaxation ratio was calculated by comparing maximal EMG activity while flexing with the average EMG activity in full flexion. Concentric (maximal EMG activity during extension) and eccentric (maximal EMG activity during flexion) ratios were also used in the analyses. RESULTS: Disability, depression, and visual analog scale scores decreased significantly after both treatments. The concentric ratio increased statistically in both groups after the treatments. The study failed to show a significant association between experienced back pain and EMG parameters. CONCLUSIONS: Both treatments seem to have a positive influence on back muscle function by improving muscle symmetry; however, the treatments had no effect on the flexion-relaxation phenomenon after 1 month. Active back exercise at home together with rehabilitation treatments might be effective and improve function for patients with chronic low back pain.

Responses of the autonomic nervous system during periods of perceived high and low work stress in younger and older female teachers.

The aim of this study was to examine the response of the autonomic nervous system in younger (mean age 31 yrs, n=14) and older (mean age 54 yrs, n=14) healthy female teachers during work periods of perceived high and low stress. In the younger participants, heart rate, cortisol excretion rate and psychosomatic symptoms were significantly higher during the high work stress period. The older participants experienced no decrease in their heart rate and cortisol excretion during the low stress period and they exhibited no significant decrease in blood pressure after the work in the evening during both periods. It may be concluded that the recovery from the stress in the older teachers was insufficient particularly in view of their elevated diastolic blood pressure during the low work stress period. Ergonomic and individually tailored measures in terms of work time control, specific relaxation techniques, and a part-time retirement may improve the stress management of older teachers.

Psychophysiological stress in high school teachers.

OBJECTIVES: The aim of this study was to follow psychophysiological stress over a year with four repeated measurements in full-time employed high school teachers and to compare their results with those obtained in the part-time retired teachers, gardeners and rescue workers. MATERIALS AND METHODS: The subjects consisted of 17 (10 females, 7 males) full-time and 9 part-time employed teachers (7 females and 2 males) in three high schools, 12 female gardeners and 13 male rescue workers. The data on job conditions, well-being, and psychosomatic symptoms were obtained by a questionnaire. The perceived stress was recorded using a visual analogue scale. The neuroendocrine reactivity was assessed by determining the diurnal urine excretion of epinephrine and norepinephrine. Electromyography of the trapezius muscle was recorded during working days in all subjects and in full-time teachers on one day in the holiday season. Blood pressure and heart rate were measured in the morning and in the afternoon. RESULTS: Psychophysiological stress in the full-time employed teachers was at similar levels on all three working days in December, March and November. Recovery from psychophysiological stress of working period was observed on summer holidays. Blood pressure, static muscle tension, perceived strain, psychosomatic symptoms and epinephrine level decreased significantly during the summer holidays as compared to the working days. The full-time employed teachers reported more perceived stress and psychosomatic symptoms than the part-time retired teachers or gardeners and rescue workers. Also static muscle activity was higher in full-time teachers than in rescue workers on the working days. CONCLUSIONS: More emphasis should be given to prevent psychophysiolocigal stress among teachers as well as to develop stress coping methods, and part-time working systems to facilitate work ability of aging teachers.