Bioavailability of long-chain n-3 fatty acids from enriched meals and from microencapsulated powder.

BACKGROUND: Despite the potential benefits of long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), intake is often low because of low consumption of oily seafood. Microencapsulated fish oil powder can improve tolerance and acceptance of LC n-3 PUFAs. Bioavailability is important to achieve efficacy. We investigated the bioavailability of LC n-3 PUFAs from microencapsulated powder in comparison with meals enriched with liquid fish oil. METHODS: Participants (N=99, age⩾50 years) of this 4-week double-blinded dietary intervention were randomized into three groups. Group 1 (n=38) received 1.5 g/d eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as ready-to-eat meals enriched with liquid fish oil; group 2 (n=30) received the same amount of these LC n-3 PUFAs as microencapsulated fish oil powder and regular meals; and group 3 (n=31) was the control group, which received placebo powder and regular meals. Blood samples were taken from fingertips at baseline and at the end point. RESULTS: Seventy-seven subjects (77.8%) completed the study. The amount of EPA in blood doubled in both groups that received LC n-3 PUFAs (P<0.05), but it did not change in the control group. The changes in DHA were less but still significant in both intervention groups. According to multivariate analysis, both intervention groups had higher end-point LC n-3 PUFA concentrations compared with placebo, but differences between intervention groups were not significant. CONCLUSION: Bioavailability of LC n-3 PUFAs in encapsulated powder is very similar to the bioavailability of LC n-3 PUFAs in ready-to-eat meals enriched with liquid fish oil. Thus, encapsulated powder can be considered useful to increase LC n-3 PUFA concentrations in blood.

Effects of sound amplification on teachers' speech while teaching.

Voice problems are common among teachers. This is most likely due to the heavy vocal load of their profession. The present study investigated one possible method to decrease the vocal load. The effects of amplification on classroom speech were studied on five Icelandic teachers (three females, two males, mean age 51 years). Classroom speech was recorded with a portable DAT recorder and a head-mounted microphone, first under ordinary conditions and in the next week while using electrical sound amplification. The average fundamental frequency (F0), sound pressure level (SPL) and phonation time were measured. According to the results, amplification significantly lowered both F0 (average 8.6 Hz for the females and 11.3 Hz for the males, p = 0.002 and 0.0001, respectively) and SPL (about 1 dB for both genders, p < 0.05), while phonation time was not significantly affected. The results suggest that electric amplification is likely to reduce vocal load.

Effects of amplified and damped auditory feedback on vocal characteristics.

This study tested two possible methods for reducing vocal load e.g. during classroom speech. Six female subjects read aloud from a text (1) under normal circumstances, (2) while hearing their own voice amplified (through headphones) and (3) with auditory feedback damped by foam plastic earplugs inserted in the outer ear canal. Fundamental frequency (F0) and sound pressure level (SPL) decreased during both amplified and damped feedback. Additionally, during amplification the relative level of F0 compared to that of the first formant diminished, likewise the alpha ratio. These changes may indicate reduced vocal fold adduction. The results suggest that both amplification and damping of auditory feedback may reduce vocal load during phonation.

Intranasal administration of diphtheria toxoid. Selecting antibody isotypes using formulations having various lipophilic characteristics.

Non-ionic excipients, having different lipophilicity, were compared for their selection of immunological response in different organs and biological fluids. In order to express the lipophilicity of the formulation, the balance between the size and strength of the hydrophilic and lipophilic groups was used, called the hydrophile-lipophile balance (HLB) value. Mice were immunized and boosted intranasally with diphtheria toxoid, and samples were taken from the blood, spleen, nasal wash, lungs, saliva, stomach, duodenum, jejunum and the skin. In general, formulations which were highly hydrophilic and highly lipophilic were not able to augment the immunological response markedly (except for IgA). Formulations having intermediate HLB values, e.g. around 9.0, stimulated both IgG1 and IgG2a production, where the HLB = 5.5 formulation seemed to stimulate mainly IgG2b and IgG3 antibody production. On the other hand, comparing the IgA concentration in various samples with respective IgG level, increasing HLB value seems to augment the production of mainly IgA antibodies. The results indicate that the antibody isotypes may be controlled, using variations in the hydrophile-lipophile balance value.