Practices in prescribing protein substitutes for PKU in Europe: No uniformity of approach.

BACKGROUND: There appears little consensus concerning protein requirements in phenylketonuria (PKU). METHODS: A questionnaire completed by 63 European and Turkish IMD centres from 18 countries collected data on prescribed total protein intake (natural/intact protein and phenylalanine-free protein substitute [PS]) by age, administration frequency and method, monitoring, and type of protein substitute. Data were analysed by European region using descriptive statistics. RESULTS: The amount of total protein (from PS and natural/intact protein) varied according to the European region. Higher median amounts of total protein were prescribed in infants and children in Northern Europe (n=24 centres) (infants <1 year, >2-3g/kg/day; 1-3 years of age, >2-3 g/kg/day; 4-10 years of age, >1.5-2.5 g/kg/day) and Southern Europe (n=10 centres) (infants <1 year, 2.5 g/kg/day, 1-3 years of age, 2 g/kg/day; 4-10 years of age, 1.5-2 g/kg/day), than by Eastern Europe (n=4 centres) (infants <1 year, 2.5 g/kg/day, 1-3 years of age, >2-2.5 g/kg/day; 4-10 years of age, >1.5-2 g/kg/day) and with Western Europe (n=25 centres) giving the least (infants <1 year, >2-2.5 g/kg/day, 1-3 years of age, 1.5-2 g/kg/day; 4-10 years of age, 1-1.5 g/kg/day). Total protein prescription was similar in patients aged >10 years (1-1.5 g/kg/day) and maternal patients (1-1.5 g/kg/day). CONCLUSIONS: The amounts of total protein prescribed varied between European countries and appeared to be influenced by geographical region. In PKU, all gave higher than the recommended 2007 WHO/FAO/UNU safe levels of protein intake for the general population.

Potential therapeutic levels of glucagon-like peptide I achieved in humans by a buccal tablet.

OBJECTIVE: Glucagon-like peptide I(7-36) (GLP-I) amide, an endogenous incretin, has been identified as a potential adjunct to the treatment of NIDDM and has been studied following intravenous and subcutaneous injection. A mucoadhesive buccal GLP-I tablet containing 119 nmol has been developed to provide transmucosal absorption as a possible alternative to injection treatment. RESEARCH DESIGN AND METHODS: Eight healthy volunteers received a single tablet under fasting conditions in this randomized double-blind placebo-controlled study. A total GLP-I immunoreactivity was measured using COOH-terminal radioimmunoassay (RIA) (total peptide activity) and NH2-terminal RIA (active, nondegraded peptide). RESULTS: The mean (+/- SE) peak GLP-I concentration was 117 +/- 19 pmol/l and occurred 30 +/- 4 min after application. The mean placebo-adjusted area under curve was 8,145 +/- 873 pmol.min-1.l-1, consistent with a relative bioavailability of 7% versus intravenous injection and 47% versus subcutaneous injection. The levels of active peptide increased in parallel with total GLP-I. Half-life of peptide activity after buccal administration was 27 and 24 min measured with COOH-terminal and NH2-terminal RIA, respectively. Placebo adjusted insulin concentrations increased to a peak of 252 +/- 57 pmol/l, glucose decreased 1.4 +/- 0.2 mmo/l, and glucagon decreased 17 +/- 3 ng/l, consistent with the increase in plasma GLP-I concentrations. CONCLUSIONS: Therapeutic plasma levels of GLP-I in humans were achieved after a single buccal tablet. No increased degradation of GLP-I was found in the buccal mucosa compared to subcutaneous tissue. This alternative treatment form may be feasible in in the future for NIDDM.

The effect of L-tryptophan administration on the concentration of probenecid in plasma and cerebrospinal fluid in patients.

The administration of large doses of probenecid has been used to study the central nervous system metabolism of catecholamines and indoleamines in patients with affective disease. It has been reported that alterations of the binding of L-tryptophan to plasma albumin binding sites occur during probenecid administration. The present study sought to determine if the administration of large doses of L-tryptophan affected probenecid concentrations in cerebrospinal fluid and/or plasma. The data indicate that during L-tryptophan treatment, plasma probenecid concentrations are reduced but that no significant alterations in cerebrospinal fluid probenecid concentrations occur. This would suggest that the kinetics of the probenecid blockade of transport of acidic biogenic amine metabolites out of cerebrospinal fluid are not altered by L-tryptophan loading.