The postmenopausal phase is associated with an accelerated rate of rise in the prevalence of vascular dysfunction and hypertension; however, the mechanisms underlying these adverse vascular changes and whether exercise training can reverse the decline in vascular function remains unclear. We examined the function of the vascular prostanoid system in matched pre- and postmenopausal women before and after 12 weeks of exercise training. Twenty premenopausal and 16 early postmenopausal (3.1±0.5 [mean±SE] years after final menstrual period) women only separated by 4 (50±0 versus 54±1) years of age were included. Before the training period, the vasodilator response to intra-arterial infusion of either the prostacyclin analog epoprostenol or acetylcholine was lower (≈13%–41%; P <0.05) in the postmenopausal compared with the premenopausal women. Acetylcholine infusion induced a similar release of prostacyclin (6-keto prostaglandin F 1a ). To elucidate the role of vasoconstrictor prostanoids, acetylcholine infusion was combined with the cyclooxygenase inhibitor ketorolac and here the vascular response to acetylcholine was reduced to a similar extent in pre- and postmenopausal women. Exercise training increased ( P <0.05) the vasodilator response to epoprostenol (≈100%–150%) and acetylcholine (≈100%–120%) infusion in the postmenopausal group. These findings demonstrate that the early postmenopausal phase is associated with a marked reduction in vascular function. Despite of a reduced sensitivity to prostacyclin, the overall balance between vasodilator and vasoconstrictor prostanoids does not seem to be altered. Exercise training can reverse the decline in vascular sensitivity to epoprostenol and acetylcholine, suggesting that beneficial vascular adaptations with exercise training are preserved in recent postmenopausal women.

The objective of this research was to investigate if breastfeeding affects the size of the thymus. Ultrasound assessment of the thymic index (a volume estimate) at birth and age 4 months in 47 healthy infants born in the hospital were used. History of feeding mode, body size and illness were registered. At 4 months the geometric mean thymic index (range) was 38.3 (16.2-83.2) in exclusively breastfed infants (n = 21), 27.3 (15.6-50.0) in partially breastfed infants (n = 13) and 18.3 (12.2-32.6) in formula fed infants (n = 13; p = 0.0001, ANOVA). This finding was independent of weight, length, sex and previous or current illness. There was no significant difference in mean thymic index at birth between the three feeding groups and mean thymic index had increased in all three groups from birth to 4 months. For the formula-fed infants it seems that the thymus remains large for a period and then decreases in size after breastfeeding has been terminated. We conclude that the thymus is considerably larger in breastfed than in formula-fed infants at the age of 4 months. The cause of this difference is unknown but human milk contains many immune modulating factors that might cause this effect.

Objective: The dose-response effects of exercise training on insulin sensitivity, metabolic risk, and quality of life were examined. Methods: Sixty-one healthy, sedentary (VO 2 max: 35 6 5 ml/kg/min), moderately overweight (BMI: 27.9 6 1.8), young (age: 29 6 6 years) men were randomized to sedentary living (sedentary control group; n ¼ 18), moderate (moderate dose training group [MOD]: 300 kcal/day, n ¼ 21), or high (high dose training group [HIGH]: 600 kcal/day, n ¼ 22) dose physical exercise for 11 weeks. Results: The return rate for post-intervention testing was 82-94% across groups. Weekly exercise amounted to 2,004 6 24 and 3,774 6 68 kcal, respectively, in MOD and HIGH. Cardiorespiratory fitness increased (P < 0.001) 18 6 3% in MOD and 17 6 3% in HIGH, and fat percentage decreased (P < 0.001) similarly in both exercise groups (MOD: 32 6 1 to 29 6 1%; HIGH: 30 6 1 to 27 6 1%). Peripheral insulin sensitivity increased (P < 0.01) (MOD: 28 6 7%; HIGH: 36 6 8%) and the homeostasis model assessment of insulin resistance decreased (P < 0.05) (MOD: -17 6 7%; HIGH: -18 6 10%). The number of subjects meeting the criteria of the metabolic syndrome decreased by 78% in MOD (P < 0.01) and by 80% in HIGH (P < 0.05). General health assessed by questionnaire increased similarly in MOD (P < 0.05) and HIGH (P < 0.01). Conclusions: Only minor additional health benefits were found when exercising $3,800 as opposed to $2,000 kcal/week in young moderately overweight men. This finding may have important public health implications.

Estimation of renal size by sonography can be performed by measuring renal length, volume, cortical volume or cortical thickness. Observer variation in these measurements is an important factor, especially when repeated measurements are compared. This study was performed to examine the magnitude of intraobserver and interobserver variations for each of the above-mentioned measurements, and to find the measurement with the lowest observer variation. Sonographic measurements were performed by 3 observers on 18 adult volunteers. The standard deviation of the difference (SDD) between any 2 pairs of measurements was used as the indicator of the magnitude of the observer variation. Renal length measurement showed the lowest observer variation with a relative SDD of 4 to 5%. Measurement of cortical thickness showed the poorest reproducibility with a relative SDD of 18 to 23%, while volumetric estimations had a relative SDD of 14 to 17%. Renal length measurement should be preferred to renal volume estimation, especially when comparing repeated measurements.