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Biomedical subjects

H Wegmann

Publications and source records attributed to H Wegmann.

12 recordsLinked to original sources

Gastrointestinal problems in airline crew members.

The presence of intestinal and extraintestinal symptoms was investigated by a symptom questionnaire in crew members (n = 190) - and as controls in age and sex matched ground based administrative employees (n = 100) - of a charter carrier and was related to the actual flight schedule of the flying staff during one month. In addition, health and illness behaviors and personal, job and life satisfaction were assessed and related to symptom scores and flight schedules. Flying staff did report significantly more dyspeptic symptoms than did ground staff, and this was found mainly with long-distance flying, since staff with short-haul experience only did not report as much upper intestinal complaints. Also, cabin crew reported significantly more intestinal symptoms than did cockpit members, and part of the upper GI symptoms could be explained by different eating behaviors, specifically more fibre intake in flying staff. With increasing intestinal symptom frequency, doctor visits and sick-days increased, and satisfaction with job and personal life decreased. Flying staff had, however, more awareness of the importance of health behaviors. It is concluded that frequent flying specifically on long distances may result in increased intestinal symptoms, presumably due to time-shift.

Absenteeism↗

Serotonin and dopamine synthesis in phenylketonuria.

Two regulation systems of the serotonin and dopamine biosynthesis in patients with classical and atypical PKU were investigated. In classical PKU, the serotonin and dopamine biosynthesis is inhibited by high L-phenylalanine in blood and tissues. The dopamine formation in vivo was inhibited by phenylalanine blood concentrations higher than 25 mg/dl: the serotonin formation was inhibited even at a phenylalanine blood concentration of only 8 mg/dl. In two patients with dihydrobiopterin synthetase deficiency, the dopamine, and even more pronounced the serotonin, excretions are considerably reduced. The dopamine excretion was reduced to about 50% and the serotonin excretion to only 10% compared to controls. Under BH4 therapy (16 mg daily), the dopamine values increased about twice, serotonin threefold and the phenylalanine blood concentration normalized to 1-1.5 mg/dl. On loading a patient with BH2 synthetase deficiency with 50 mg/kg deuterated tryptophan-d5 and 150 mg/kg deuterated tyrosine d2 (phenylalanine blood concentration of 16 mg/dl), deuterated dopamine d1 and serotonin d4 could only be formed in detectable amounts after BH4 administration. During BH4 therapy the amount of dopamine d1 and serotonin d4 formed was lower than but comparable to normal controls.

Dopamine↗

Nutritive value of N-acetyl-L-tryptophan in man.

The nutritive value of N-acetyl-L-tryptophan was investigated by loading tests with deuterated L-tryptophan and deuterated N-acetyl-L-tryptophan in three healthy adults, and by a 7 day-long feeding experiment with deuterated N-acetyl-L-tryptophan in one healthy adult. After loading with deuterated N-acetyl-L-tryptophan, serum levels of deuterated tryptophan and kynurenine were only about 10%, and the amounts of deuterated 5-hydroxyindole-3-acetic acid excreted in 24 h approximately 30% of those found after deuterated tryptophan loading. During the feeding experiment with deuterated N-acetyl-L-tryptophan, the serum level of deuterated tryptophan remained below 20% of total serum tryptophan, and serum protein fell below the normal range. It is concluded that the nutritive value of N-acetyl-L-tryptophan is inferior to that of L-tryptophan. Contradictory findings of earlier studies are discussed.

Blood Proteins↗

Selective ion monitoring of tryptophan, N-acetyltryptophan and kynurenine in human serum. Application to the in vivo measurement of tryptophan pyrrolase activity.

A specific method is described for the determination of deuterated and non-deuterated N-acetyltryptophan, tryptophan and kynurenine in human serum and urine using gas chromatography-mass fragmentography. N-Acetyltryptophan was analysed as the N-trimethylsilyl methyl ester derivative; tryptophan and kynurenine were converted into their N-pentafluoropropionyl methyl esters. N-Acetyl-DL-tryptophan-d11, tryptophan-d8 and kynurenine-d2 were used as internal standards. The coefficients of variation were found to be about 8% (n = 9) for tryptophan and N-acetyltryptophan and about 2.4% (n = 9) for kynurenine. Using this method, an in vivo determination of the tryptophan pyrrolase activity [L-tryptophan oxygen 2,3-oxidoreductase (decyclizing), E.C. 1.13.11.11] is possible by loading the subjects with deuterated L-tryptophan-d5 and subsequently measuring the deuterated L-kynurenine-d4 formed and the residual L-tryptophan-d5.

Acetylation↗