Effect of regular voluntary exercise on resting cardiovascular responses in SHR and WKY pregnant rats.

The purpose of this study was to assess the influence of regular voluntary exercise in pregnant normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats on 1) uteroplacental perfusion and mean arterial pressure in the resting conscious condition and 2) fetal number, fetal weight, and number of fetal resorptions. WKYs and SHRs were randomly assigned to standard cages [CWKY (n = 10); CSHR (n = 6)] or cages with activity wheels [EWKY (n = 7); ESHR (n = 8)]. EWKYs and ESHRs exercised for 12 wk, and then all rats were bred and experiments were conducted on gestational day 17. Resting blood flow (microspheres), heart rate (HR), and mean arterial pressure (Pa) were measured. No significant difference was found in Pa, HR, uterine blood flow (ESHRs 52 +/- 8 ml.min-1.100 g-1; CSHRs 28 +/- 6 ml.min-1.100 g-1), or maternal placental blood flow (ESHRs, 122 +/- 31 ml.min-1.100 g-1; CSHRs 78 +/- 21 ml.min-1.100 g-1) among the groups. Exercise altered the relationship between maternal placental and uterine blood flow and Pa in the SHR; SHRs with lower Pa maintained higher placental and uterine blood flow after training. Before gestation ESHRs ran on average more kilometers per week than EWKYs (43 +/- 3 vs. 34 +/- 4), but during gestation ESHRs averaged fewer kilometers per week than EWKYs (16 +/- 4 vs. 22 +/- 4). Succinate dehydrogenase activity was higher in the white vastus lateralis (1.02 +/- 0.2 mumol cytochrome c reduced.min-1.g wet wt-1) and vastus intermedius (3.1 +/- 0.5 mumol cytochrome c reduced.min-1.g wet wt-1) muscles of ESHRs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Association of sickness absence with poor sleep and depressive symptoms in shift workers

A cross-sectional study was conducted to evaluate the contribution of daily sleep habits and depressive symptoms to sickness absences of shift workers. A self-administered questionnaire that solicited answers about sleep, symptoms of depression, sickness absence, diseases/injuries, and lifestyle factors was submitted to a sample of 522 rotating shift workers between the ages of 18-59 (mean 27) yrs of an electric equipment manufacturing company. The seven features of sleep queried were daily hours of sleep, time to fall asleep, awakening during sleep, early morning awakening, sleep well at night, sufficiency of sleep, and excessive daytime sleepiness at work. The responses were assessed over the subject's previous 1-yr period. Each sleep feature, except daily sleeping hours, was dichotomized by the following responses: (1) taking more than 30min to fall asleep (difficulty initiating sleep; DIS), (2) awakening during sleep almost every day (difficulty maintaining sleep; DMS), (3) early morning awakening almost every day (EMA), (4) sleeping very poorly or not so well at night, (5) definite or somewhat insufficient nightly sleep, and (6) excessive daytime sleepiness at work almost every day (EDS). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Sickness absence was calculated by asking subjects "How many days in total have you been absent from work due to sickness, including paid vacation, in the last 1-yr period?" The responses were divided into three groups that included no (0 days) sickness absences (reference group, n=235 subjects), 1 to 4 days (short-term, n=199 subjects), and 5 days or more (long-term, n = 88 subjects). Compared to the prevalence of sleep features of the reference group, workers with short-term absence showed a significantly higher prevalence of EMA with an odds ratio (OR) of 5.3, 95% confidence interval (CI) 1.3-22.0. Long-term absence was significantly associated with DMS (OR = 2.1, 95%CI 1.0-4.6), EMA (OR = 5.6, 95%CI 1.0-28.7), sleeping poorly at night (OR= 2.6, 95%CI 1.4-5.0), and high depressive symptoms (OR = 2.0, 95%CI 1.0-3.7) according to the CES-D score of >16, after adjusting for multiple confounding variables. These data point to an association between both the parameters of poor sleep and symptoms of deep depression when self-reported sickness absence is frequent. The association is particularly strong with long-term absence in male shift workers.     

The effect of supplementation with docosahexaenoic and arachidonic acid derived from single cell oils on plasma and erythrocyte fatty acids of pregnant women in the second trimester

This study was performed to investigate whether supplementation of docosahexaenoic acid (DHA) and arachidonic acid (AA) to pregnant women would enhance their DHA levels, both in plasma and in erythrocyte phospholipids, without reducing the content of n-6 long-chain ployenes (LCP) usually seen when DHA is supplemented alone. Healthy pregnant women, in the second trimester, were randomly assigned to either the control group (n=12) or the intervention group (n=12). The control group received no supplements and the intervention group received daily during 4 weeks encapsulated algae-derived DHA oil (0.57 g DHA/day) and fungal-derived AA oil (0.26 g AA/day). The fatty acid compositions of plasma and erythrocyte phospholipids were determined in weekly-collected blood samples. DHA and n-6 LCP levels of the control group were unchanged after 4 weeks. Compared to the control group, DHA levels in plasma an erythrocytes of the intervention group increased significantly. No significant reductions were found in the levels of AA and total n-6 LCP. The supplement proved to be effective in increasing the DHA levels in both plasma and erythrocyte without a concomitant decline of the n-6 LCP.     

Toddler formula supplemented with docosahexaenoic acid (DHA) improves DHA status and respiratory health in a randomized,double-blind,controlled trial of US children less than 3 years of age

Studies of docosahexaenoic acid (DHA) intake and status in US toddlers are lacking. One national survey found low DHA intakes. The objectives of this double-blind, randomized study were to (a) determine usual DHA intakes, (b) measure the effect of consuming formulas with DHA on red blood cell (RBC) and plasma DHA and (c) record adverse events in US children between 18 and 36 months of age. Children aged 18–36 months were provided 237-ml formula with 0, 43, or 130 mg DHA per day for 60 days. Blood was obtained at 0 and 60 days and 24-hour dietary recalls at 0, 30 and 60 days. Usual median daily DHA intake was 13.3 mg. RBC DHA increased in a dose-dependent manner with increasing DHA intake (p<0.05). Toddlers consuming the formula with 130 mg DHA per day have fewer adverse events (p=0.007) and a lower incidence of respiratory illness (p=0.024), compared to the formula without DHA. US toddlers have low DHA intake and status. Modest increases in DHA intake in toddlers might improve development, including respiratory health.     

A PROTRACTED FORAGING AND ATTENDANCE CYCLE IN FEMALE JUAN FERNÁNDEZ FUR SEALS

Previous studies of fur seals suggest that the attendance patterns and consequent temporal patterning of energy transfer from mother to pup follows a latitudinal cline. While data from subpolar, tropical, and some temperate latitude species support the postulated cline, data for the temperate latitude Juan Fernández fur seal do not. Maternal foraging trips and associated visits ashore were the longest of all otariids studied to date. The first foraging trip postpartum averaged 10.2 d ( n = 51 females, range 1–22.5), foraging trips combined averaged 12.3 d ( n = 100, range 1.0-25.0), and visits ashore averaged 5.3 d ( n = 91, range 0.3-15.8) over the three seasons of study. Only duration of lactation was intermediate between subpolar and tropical strategies as predicted. Dive records suggest that these females feed almost exclusively at night at depths of less than 10 m and at distances of more than 500 km offshore. The prey species of this fur seal, primarily myctophids and squid, migrate to the surface at night and are patchily distributed. Foraging trip length varied between years in conjunction with shifts in seasurface temperature and type of prey consumed. We suggest that distribution of prey, irrespective of latitude, dictates foraging patterns of fur seals and leads to the exceptionally long foraging trips and visits ashore observed in this species.     

Temperature during the day, but not during the night, controls flowering of Phalaenopsis orchids

Phalaenopsis orchids are among the most valuable potted flowering crops commercially produced throughout the world because of their long flower life and ease of crop scheduling to meet specific market dates. During commercial production, Phalaenopsis are usually grown at an air temperature > or =28 degrees C to inhibit flower initiation, and a cooler night than day temperature regimen (e.g. 25/20 degrees C day/night) is used to induce flowering. However, the specific effect of day and night temperature on flower initiation has not been well described, and the reported requirement for a diurnal temperature fluctuation to elicit flowering is unclear. Two Phalaenopsis clones were grown in glass greenhouse compartments with constant temperature set points of 14, 17, 20, 23, 26, or 29 degrees C and fluctuating day/night (12 h/12 h) temperatures of 20/14, 23/17, 26/14, 26/20, 29/17, or 29/23 degrees C. The photoperiod was 12 h, and the maximum irradiance was controlled to < or =150 micromol m(-2) s(-1). After 20 weeks, > or =80% of plants of both clones had a visible inflorescence when grown at constant 14, 17, 20, or 23 degrees C and at fluctuating day/night temperatures of 20/14 degrees C or 23/17 degrees C. None of the plants were reproductive within 20 weeks when grown at a constant 29 degrees C or at 29/17 degrees C or 29/23 degrees C day/night temperature regimens. The number of inflorescences per plant and the number of flower buds on the first inflorescence were greatest when the average daily temperature was 14 degrees C or 17 degrees C. These results indicate that a day/night fluctuation in temperature is not required for inflorescence initiation in these two Phalaenopsis clones. Furthermore, the inhibition of flowering when the day temperature was 29 degrees C and the night temperature was 17 degrees C or 23 degrees C suggests that a warm day temperature inhibits flower initiation in Phalaenopsis.     

The influence of supplemental docosahexaenoic and arachidonic acids during pregnancy and lactation on neurodevelopment at eighteen months

Docosahexaenoic acid (DHA) and arachidonic acid (AA) are important for neurodevelopment. The effects of DHA (220 mg/day, n=41), DHA+AA (220 mg/day, n=39) or placebo (n=34) during pregnancy and lactation on neurodevelopment at 18 months, and the relations between umbilical cord DHA, AA and Mead acid and neurodevelopment were studied. An age-specific, standardized neurological assessment for the evaluation of minor neurological dysfunction (MND), and the Bayley Scales of Infant Development (BSID) were used. The intervention did not influence any of the outcomes. Umbilical venous (UV) Mead acid was negatively and n-6 fatty acids were weakly positively associated to the BSID mental developmental index. Children with simple MND had lower UV DHA compared to normally classified children. We conclude that relatively short-term maternal DHA or DHA+AA supplementation does not influence neurodevelopment at toddler age, although some parameters of brain development are related to perinatal DHA and AA status.     

Short-day melatonin pattern advances puberty in seasonally breeding rhesus monkeys (Macaca mulatta)

Prepubertal, spring-born females (Group H: N = 5) living outdoors were given a daily injection of melatonin (0.70 microgram/kg, s.c.) late in the afternoon to produce a short-day melatonin pattern equivalent to a night of approximately 14 h. The dose of melatonin produced serum concentrations of melatonin which simply extended, within the 24 h day, the normal endogenous nighttime elevation (80-100 pg/ml). The study was started in March when the females were 23 months of age and continued through January. Parameters of sexual maturation for this group were compared to those of untreated, age-matched females (Group C: N = 5) which also lived outdoors under changing environmental conditions. Melatonin treatment significantly advanced age at first perineal swelling (23.9 +/- 0.5 vs 30.5 +/- 0.2 months) and menarche (26.2 +/- 0.9 vs 31.2 +/- 2.4 months). Since all of the females were spring-born, these events occurred earlier in the year in Group H females (swelling: April vs October; menarche: June vs November). Furthermore, 4/5 Group H females exhibited first ovulation in December at 31.8 +/- 0.3 months. None of the Group C females ovulated during their 2nd year, but all did so the next breeding season at 43.5 +/- 0.3 months. All first ovulations in females had luteal-phase progesterone concentrations elevated for at least 12 days with peaks greater than 3.0 ng/ml. Body weights were similar between groups until the post-menarchial interval when weight gain was greater in the melatonin-treated females. A similar pattern of group differences also was observed for serum concentrations of growth hormone and somatomedin-C. In addition, prolactin concentrations were seasonally elevated during the summer months in both groups, but concentrations fell to nadir values by August in Group H females and remained elevated until October in Group C animals. These results suggest that, in adolescent females housed outdoors, exposure to a short-day melatonin pattern permits sexual maturation to be initiated at an earlier age, allowing first ovulation to occur in the months immediately after menarche. A long-day melatonin pattern, typically experienced by females at this developmental age, may actually delay the initiation of maturational events until the subsequent fall months.     

Reproductive behavior of the honeydew moth,Cryptoblabes gnidiella

Summary

The reproductive behavior of the honeydew moth, Cryptoblabes gnidiella (Millière) (Lepidoptera: Pyralidae), was studied in the laboratory. The sex ratio was 1.1:1, males to females, in both laboratory and field stocks. Most of the females that mated did so during the first night after emergence; males began mating on the following night. Mating occurred 1–2 h before dawn and averaged 100 min. Both sexes mated only once in one night. Most females mated only once in their lifetime, a few mated 2–4 times, whereas males mated up to six times per lifetime. Insects that lived longer also mated more times. When the sex ratio was altered from 3:1 to 1:3, males to females, the percentage of females that mated in one night dropped from 90 to 65, whereas the number of matings per male rose from 0.32 to 2.25. When fresh one-day-old females were provided daily at a ratio of three per male, the males averaged 1.4 matings per lifetime vs. 2.6 with 2- to 3-day-old females. A delay in mating did not affect the percentages of males and females that mated; highest percentages were obtained with 2- to 4-day-old males and females, but a delay in mating resulted in egg fertility dropping from 91 % to 73 %. The preoviposition period lasted a full day after mating, and then most of the eggs were laid during the first night. Average fecundity was 105 eggs per female (maximum: 230).     

Circadian pattern of plasma melatonin concentrations in the marmoset monkey (Callithrix jacchus)

This study describes the concentrations of melatonin in plasma samples taken from marmoset monkeys (Callithrix jacchus) every 4 h over three 24-h periods. A circadian pattern of secretion was apparent, with higher levels recorded at night (20.00–08.00 h) than during the day (08.00–20.00 h) and a peak concentration at 20.00 h. There was a significant difference in the mean day and night concentrations (32.5 ± 4.5 pg/ml versus 49.0 ± 6.9 pg/ml, respectively) with individual concentrations ranging between<10–60 pg/ml in the day and 15–200 pg/ml at night. Circadian plasma melatonin concentrations were similar over the three 24-h periods, in male (n = 3) and female (n = 3) monkeys, and in dominant (cyclic, n = 5) and subordinate (acyclic, n = 4) females. The results show a less pronounced circadian profile in the marmoset than is seen in the human but a similar profile to that in the seasonally breeding rhesus monkey.     

Energetics and litter size variation in domestic dog Canis familiaris breeds of two sizes

We measured resting metabolic rate (RMR), daily energy expenditure (DEE) and metabolisable energy intake (MEI) in two breeds of dog during peak lactation to test whether litter size differences were a likely consequence of allometric variation in energetics. RMR of Labrador retrievers (30 kg, n=12) and miniature Schnauzers (6 kg, n=4) averaged 3437 and 1062 kJ/day, respectively. DEE of Labradors (n=6) and Schnauzers (n=4) averaged 9808 and 2619 kJ/day, respectively. MEI of Labradors (n=12) was 22448 kJ/day and of Schnauzers (n=7) was 5382 kJ/day. DEE of Labrador pups (2.13 kg, n=19) was 974 kJ/day and Schnauzers (0.89 kg, n=7) were 490 kJ/day. Although Labradors had higher MEIs than Schnauzers during peak lactation, there was no difference in mass-specific energy expenditure between the two breeds. Hence, it is unlikely that litter size variation is a likely consequence of differences in maternal energy expenditure. Individual offspring were relatively more costly for mothers of the smaller breed to produce. Therefore, litter size variations were consistent with the expectation that smaller offspring should be more costly for mothers, but not that smaller mothers should per se invest more resources in reproduction.     

Association of meteorological and day-of-the-week factors with emergency hospital admissions in Fukuoka, Japan

We carried out a statistical study of the influence of meteorological and day-of-the-week factors on the intrinsic emergency patients transported to hospitals by ambulance. Multiple piecewise linear regression analysis was performed on data from 6,081 emergency admissions for 1 year between April 1997 and March 1998 in Fukuoka, Japan. The response variable was the daily number of emergency patients admitted with three types of disease: cerebrovascular, respiratory and digestive diseases. The results showed that the number of emergency patients admitted daily with cerebrovascular disease was significantly associated with temperature on the day of admission and whether the day was Sunday. As it became colder than 12 degrees C, emergency admissions of patients with cerebrovascular disease increased drastically, reaching a plateau at 4 degrees C. On the 3rd and 7th days after the temperature fell below 10 degrees C, the daily admission of patients with respiratory disease significantly increased. We also observed a weak association between emergency admissions of patients suffering from digestive disease and rising barometric pressure on the day of admission.     

Variation in the grazing behaviour of dairy cows measured by a vibrarecorder and bite count monitor

Ten Friesian dairy cows were fitted on the neck with a Walker pedometer to evaluate the pedometer as a low-cost means of recording grazing bite number, and a Vibrarecorder for comparison and to evaluate the between-cow and between-day coefficients of variation (CV) of grazing bouts, in order to evolve an optimum recording strategy. The total number of daily bouts averaged 5.01 with a mean duration of 1.85 h, giving a total grazing time of 9.27 h per cow per day. The grazing time recorded by the Virarecorders was generally linearly related to total daily bites recorded by the pedometers, although in some cases a quadratic function was significant which was assumed to arise from variation in the biting rate at high grazing times. The between-cow CV of daily grazing time was greater than the between-day CV, but at certain times of the day, particularly at night, the between-day CV was very high. More variation occurred in grazing bout duration than bout number and the variation in total bite number tended to be greater than grazing time.     

Treatment of nocturnal asthma: the role of sustained-release theophylline and oral beta-2-mimetics

In two double-blind, multiple-dose cross-over studies the therapeutic effects of SR theophylline preparations given once each night (mean 11.2 mg/kg per day) versus twice daily in equal doses (mean 10.3 mg/kg per day) (study I) and SR-terbutaline in equal doses (mean 0.25 mg/kg per day) versus SR theophylline in unequally divided daily doses (mean 5.3 mg/kg morning dose, 10.6 mg/kg evening dose) study II) were compared in 19 patients with nocturnal asthma. At the end of each treatment period drug serum concentrations and PEFR were measured every 2 hr over a 24-hr period. With the twice-daily, equally divided regimen, serum theophylline concentrations were lower at night than during the day (mean 9.4 +/- 0.9 versus 11.3 +/- 1.0 mg/l). With the single evening administration, serum theophylline concentrations were considerably higher at night (Cmax 16.3 +/- 1.4 mg/l) and the circadian variation of PEFR was significantly reduced. PEFR was higher during night and early morning (283 +/- 14 versus 217 +/- 11 l/min, P less than 0.005). During daytime in study II, PEFR values were slightly higher with theophylline than terbutaline. There was no significant difference in peak flow between either treatment during the night and early morning. However, additional use of inhaled beta-2-mimetics because of asthmatic attacks occurred more often during terbutaline (79 times in 8/10 patients) than theophylline treatment (29 times in 5/10 patients). Symptom scores, number of attacks and side-effects clearly favor the theophylline regimen. We conclude that for patients with nocturnal asthma a once-nightly dose of SR theophylline can be sufficient for stabilization of the airways.     

Energetics of bluetongue lizards (<Emphasis Type="Italic">Tiliqua scincoides</Emphasis>) in a seasonal tropical environment

We studied the physiological ecology of bluetongue lizards (Tiliqua scincoides) on the Adelaide River floodplain in tropical Australia to determine the seasonal patterns of energy expenditure and to determine the mechanisms by which seasonal differences were achieved. Field metabolic rates (FMR) were significantly lower in the dry season (37.6 kJ kg(-1) day(-1); n=9) than in the wet (127.3 kJ kg(-1) day(-1); n=7). Water flux was also lower in the dry season (6.8 ml kg(-1) day(-1); n=9) than in the wet (39.4 ml kg(-1) day(-1); n=7). Measurements of body temperatures (T(b)) and movements of free-ranging animals, and standard metabolic rate (SMR) of recently caught animals, allowed a detailed analysis of energy budgets for wet and dry seasons. In the dry, bluetongue lizards expended 90 kJ kg(-1) day(-1) less energy than in the wet season. Unlike some other lizards of the wet-dry tropics, SMR did not differ between seasons. About 5% of the seasonal difference in FMR was due to lower night time T(b) during the dry season, and about 7% was due to lower diurnal T(b). The remaining 88% of the decrease in energy expended in the dry season was due to a substantial decrease in other costs that may include reproduction, growth, digestion and activity. If we assume the animals fed daily and the costs of digestion are taken into account, the estimates are: 14% of the savings result from lower T(b) at night, 20% from lower T(b) in the day, and 66% result from decreased activity. It is therefore apparent that, unlike some agamid and varanid lizards that use a combination of behavioural and physiological mechanisms to conserve energy when food and water are limited, bluetongue lizards primarily use behavioural mechanisms to achieve a dramatic reduction in energy expenditure in the dry season.     

Years of Life Lost (YLL) in Colombia 1998-2011: Overall and Avoidable Causes of Death Analysis

ObjectiveEstimate the Years of Life Lost (YLL) for overall and avoidable causes of death (CoD) in Colombia for the period 1998-2011.MethodsFrom the reported deaths to the Colombian mortality database during 1998-2011, we classified deaths from avoidable causes. With the reference life table of the Global Burden of Disease (GBD) 2010 study, we estimated the overall YLL and YLL due to avoidable causes. Calculations were performed with the difference between life expectancy and the age of death. Results are reported by group of cause of death, events, sex, year and department. Comparative analysis between number of deaths and YLL was carried out.ResultsA total of 83,856,080 YLL were calculated in Colombia during period 1998-2011, 75.9% of them due to avoidable CoD. The year 2000 reported the highest number of missed YLL by both overall and avoidable CoD. The departments with the highest YLL rates were Caquetá, Guaviare, Arauca, Meta, and Risaralda. In men, intentional injuries and cardiovascular and circulatory diseases had the higher losses, while in women YLL were mainly due to cardiovascular and circulatory diseases.ConclusionsThe public health priorities should focus on preventing the loss of YLL due to premature death and differentiated interventions by sex.     

Diurnal urinary 6-sulfatoxymelatonin levels among healthy Danish nurses during work and leisure time

The present study aims to examine the influence of evening and night shift work, compared to day shift work, on melatonin secretion in nurses in a field setting. Effects were examined during a workday and during a day off. Both fixed schedules and mixed or rotating schedules were studied. In total, 170 nurses were studied: 89 nurses worked fixed schedules, 27 nurses worked the day shift, 12 nurses worked the evening shift, 50 nurses worked the night shift, and 82 nurses worked mixed schedules, with data collected during a day (n=17), evening (n=14), or night shift (n=50). All spot urine samples were collected during 24 h from the participants on a work day and on a day off and were analyzed for 6-sulphatoxymelatonin. On the day of urine sampling, participants filled in the Karolinska Sleep Diary. Additional information was collected through a telephone interview. Data were analyzed using a mixed procedure with autoregressive covariance structure. The present study showed that shift work affected the concentrations of 6-sulphatoxymelatonin in the short term by lower excretion in urine from nurses working the night compared to day shift on a workday and on a day off as well. No significant differences were observed between a workday and a day off when doing day and evening shifts, irrespective of mixed and fixed schedules. Sleep length was reduced workdays (from 6.1-6.8 h) among all nurses, compared to days off (from 7.8-8.7 h).     

Blood flow distribution in rat muscles during preexercise anticipatory response

Previous work has suggested that preexercise "anticipatory" blood flow distribution in the muscles of rats is influenced by the intensity of the preceding conditioning or training program. The purpose of this study was to carefully control the conditioning programs for control, low-speed conditioned, and high-speed conditioned rats to determine the respective effects on preexercise mean arterial pressure (Pa), heart rate (HR), and blood flow distribution in muscles and other organs. Control (daily placement on treadmill, no exercise), low-speed conditioned (daily treadmill walking up a 12 degree incline at 15 m/min), and high-speed conditioned (daily treadmill galloping up a 12 degree incline at 50 m/min) rats were conditioned for 2-4 wk in their respective programs. On the experimental day, the circulatory variables were measured immediately before exercise by using the same preexercise regimen as during the conditioning sessions. Pa, HR, and blood flow distribution were the same in control and low-speed conditioned rats (P greater than 0.05). However, in high-speed conditioned rats, HR (+9%), Pa (+7%), and white gastrocnemius muscle (+46%) blood flow were higher than in controls (P less than 0.05). The higher white muscle flow was the result of the higher Pa and lower resistance to flow. These data demonstrate that specific changes in preexercise anticipatory blood flow distribution among muscles occur during exercise conditioning programs and that the changes are dependent on the intensity of the conditioning regimen. The mechanisms responsible for the adaptations are not known.     

Docosahexaenoic acid transfer into human milk after dietary supplementation: a randomized clinical trial

Docosahexaenoic acid (DHA) is important for infant development. The DHA transfer from maternal diet into human milk has not been investigated in detail. We studied the effects of DHA supplementation on the fatty acid composition of human milk and the secretion of dietary (13)C-labeled fatty acids, including DHA, into human milk. Ten lactating women were randomized to consume, from 4 to 6 weeks postpartum, an oil rich in DHA (DHASCO, 200 mg of DHA/day) (n = 5) or a placebo oil (n = 5). Dietary intakes were followed by 7-day protocols. On study day 14 a single dose of [U-(13)C]DHASCO was given orally, milk samples were collected over 48 h, and milk production was recorded. Milk fatty acid composition was determined by gas-liquid chromatography and isotopic enrichment was determined by gas chromatography- combustion-isotope ratio mass spectrometry (GC-C-IRMS). Milk DHA content did not differ between the supplemented and placebo group at study entry (0.29 vs. 0.28 wt%, median). After 2 weeks of supplementation the milk DHA content was almost 2-fold higher in the supplemented versus placebo group (0.37 vs. 0.21 wt%, P = 0.003). Cumulative recovery of [(13)C]palmitic, [(13)C]oleic, and [(13)C]docosahexaenoic acids in human milk at 48 h was similar between supplemented and placebo groups (palmitic acid 7.40 vs. 8. 14%, oleic acid 9.14 vs. 9.97%, and docosahexaenoic acid 9.09 vs. 8. 03% of dose, respectively). Notable lower recovery was observed for [(13)C]myristic acid in both the supplemented and placebo groups, 0. 62 versus 0.77% of dose.Dietary DHA supplementation increases the DHA content in human milk. DHA transfer from the diet into human milk is comparable to palmitic and oleic acid transfer.