Characterisation of urinary WFDC12 in small nocturnal basal primates, mouse lemurs (Microcebus spp.).

Mouse lemurs are basal primates that rely on chemo- and acoustic signalling for social interactions in their dispersed social systems. We examined the urinary protein content of two mouse lemurs species, within and outside the breeding season, to assess candidates used in species discrimination, reproductive or competitive communication. Urine from Microcebus murinus and Microcebus lehilahytsara contain a predominant 10 kDa protein, expressed in both species by some, but not all, males during the breeding season, but at very low levels by females. Mass spectrometry of the intact proteins confirmed the protein mass and revealed a 30 Da mass difference between proteins from the two species. Tandem mass spectrometry after digestion with three proteases and sequencing de novo defined the complete protein sequence and located an Ala/Thr difference between the two species that explained the 30 Da mass difference. The protein (mature form: 87 amino acids) is an atypical member of the whey acidic protein family (WFDC12). Seasonal excretion of this protein, species difference and male-specific expression during the breeding season suggest that it may have a function in intra- and/or intersexual chemical signalling in the context of reproduction, and could be a cue for sexual selection and species recognition.

Food mineral composition and acid-base balance in preterm infants.

BACKGROUND: Due to a transient age-related low renal capacity for net acid excretion, preterm infants fed formula are at a considerable risk of spontaneously developing incipient late metabolic acidosis, clinically characterized by e.g., disturbed bone mineralization and impaired growth. AIM OF THE STUDY: From acid-base data in blood and urine under different diets of modified human milk or preterm formulas is attempted to explore the impact of food mineral (and protein) composition on renal regulation and systemic acid-base balance in preterm infants. PATIENTS AND METHODS: Data were collected from 48 infants fed their own mother's milk (28 native human milk, 20 enriched with fortifier) and 34 patients on formula (23 on a standard batch, 11 on a modified batch with reduced acid load). Intake of food was measured and acid-base data were determined in blood and timed-urine (8-12 h) samples. RESULTS: Differences in mineral composition of the diets led to considerable differences of daily "alkali-intake", without significant effects on non-respiratory (base excess, BE) and respiratory (PCO(2)) acid-base data in the blood. In contrast, a highly significant proportionality between individual dietary alkali intake and daily renal base (Na(+) + K(+)-Cl(-)) excretion was observed (y = 0.32x-0.70, n = 80, r = 0.77, P < 0.0001), irrespective of the type of the diet. CONCLUSION: Renal base saving mechanisms are normally effective in preterm infants to compensate for differences in dietary acid-base load. Generally, nutritional acid-base challenges can be judged much earlier and more safely by urinary than by blood acid-base analysis. Taking into account the age specific low capacity for renal NAE, the relatively high nutritional acid load of preterm standard formula should be reduced.

Relationship between the calcium-to-protein ratio in milk and the urinary calcium excretion in healthy adults--a controlled crossover study.

Over the years, doubts have arisen concerning the use of milk as a calcium source in the prevention of osteoporosis, particularly because of potential offsetting effects of protein and phosphorus. Thus, a new milk product with a higher calcium content and lower contents of protein, phosphorus, and energy was developed. A controlled crossover study was done to determine the way in which substitution of the new milk product (860 mL) for normal milk (1000 mL) in the diet of healthy adults affected the urinary excretion of calcium and hydroxyproline. Short-term consumption of the product significantly lowered 24-h urinary calcium excretion by approximately 0.65 +/- 0.19 mmol/d (means +/- SEM, p less than 0.001). The ratio of fasting urinary hydroxyproline to creatinine did not decrease, indicating no significant reduction of bone resorption in our subjects. Elderly people in particular might benefit from the new product because it reduces their calcium loss as well as their intake of protein, phosphorus, energy, and liquid volume.