[Familial nesidioblastosis].
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Adenoma, Islet Cell↗
Biomedical subjects
F K Trefz
Publications and source records attributed to F K Trefz.
Sensitive in vivo assay of the phenylalanine hydroxylating system with a small intravenous dose of heptadeutero L-phenylalanine using high pressure liquid chromatography and capillary gas chromatography/mass fragmentography.
A method is described which allows the in vivo determination of the phenylalanine hydroxylating system in atypical and classical phenylketonuria. Phenylalanine-d7 is administered i.v. (0.030 g/kg body weight) within 10 min. Tyrosine-d6 in plasma is measured from 30 to 240 min post load by using a computerized capillary gas chromatography/mass fragmentography system. In two patients with hyperphenylalaninemia, the residual activity of the phenylalanine hydroxylating system was 15.7 and 3.7% of the normal, in two phenylketonurics 1.5 and 0.3% respectively. The in vivo figures correspond well to the in vitro assay of the residual activity of the phenylalanine hydroxylase in needle liver biopsy material.
Adult↗
In vivo determination of phenylalanine hydroxylase activity using heptadeutero-phenylalanine and comparison to the in vitro assay values.
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Deuterium↗
[Endocarditis lenta caused by Lactobacillus salivarius subsp. salicinicus (author's transl)].
After two tooth extractions performed without antibiotic cover endocarditis lenta occurred in a ten-year-old girl. The causative organism isolated was Lactobacillus salivarius subsp. salicinicus, the first such reported case. The child has a small, haemodynamically insignificant, ventricular septal defect. A cure was achieved after long-term administration of penicillin G in high doses, at first combined with ampicillin. There were no complications.
Ampicillin↗
Determination of deuterium-labeled phenylalanine and tyrosine in human plasma with high pressure liquid chromatography and mass spectrometry.
A method is presented for the recovery of deuterated phenylalanine and tyrosine from human plasma. Phenylthiohydantoine derivatives are formed (Edman reaction) which are separated and isolated by high pressure liquid chromatography. The relative concentration of the deuterated amino acid is determined by mass spectrometry. The results obtained from a healthy person after oral loading with 40% monodeuterated L-phenylalanine are presented. The method appears to be suitable for in vivo studies of phenylalanine metabolism in humans.
Chromatography, High Pressure Liquid↗
[Point of micropreparative high pressure liquid chromatography and thin-layer chromatography for the identification of indole compounds in human plasma (author's transl)].
Results are presented on the analysis of indolic metabolites of tryptophan in human plasma, using high-pressure liquid chromatography and thin-layer chromatography. Dichloromethane/ethanol extracts of denaturated plasma were analysed. Thin-layer chromatography proved to be more advantageous for the analysis of this class compounds because it is possible to use a specific staining reagent (4-dimethylaminobenzaldehyde). The advantage of high-pressure liquid chromatography lies in the rapid isolation and purification of unknown compounds for identification in an off-line method. This application is demonstrated with the isolation of N-acetyltryptophan from human plasma. Preliminary results are presented on the plasma concentration of indole-3-lactic acid, indole-3-acetic acid and N-acetyltryptophan in healthy persons, phenylketonurics, and uremic patients.
Adolescent↗
Quantitative determination of cortisol in human plasma by high-pressure liquid chromatography.
A method is described for the determination of cortisol in human plasma by high-pressure liquid chromatography. The simplified extraction procedure makes the method applicable to routine clinical assays. Partition chromatography is carried out on a Zorbax-Sil column with the eluent system dichloromethane-ethanol-water. A 78% recovery was obtained for cortisol. The detection limit is 1 mug per 100 ml in 1 ml of plasma. Cortisol values were determined in samples from a random selection of patients.
Adolescent↗
A study of urinary tryptophan metabolites in relation to the phenylalanine content of semi-synthetic diets in a patient with phenylketonuria.
The influence of different phenylalanine (Phe) levels in semi-synthetic diets on the urinary excretion of tryptophan (Try) metabolites was studied in one untreated phenylketonuric (PKU) patient. Low dietary Phe decreased the excretion of indoleacetic acid, indolelactic acid, indican and Try but did not increase 5-hydroxyindoleacetic acid. Under the low Phe diet, the excretion of N-acetyltryptophan, kynurenic and xanthurenic acid are greatly increased in the urine after a Try load. The possible significance of the extensive acetylation of Try and Phe is discussed in relation to the low blood levels of Try and PKU and to the phenomenon of decreasing blood Phe levels in PKU.
Adult↗
Haplotype distribution and mutations at the PAH locus in Croatia.
Restriction fragment length polymorphism (RFLP) haplotypes and mutations at the phenylalanine hydroxylase (PAH) locus have been studied in 25 unrelated families from Croatia. The results of RFLP analysis demonstrated that 80% of the mutant alleles were associated with three haplotypes (1, 2 and 4). Eight mutations were detected on the background of six mutant haplotypes, comprising 68% of phenylketonuria (PKU) alleles in Croatia. The mutation in codon 408 was most frequent, as was the haplotype 2 allele with which it was associated. These data are in accordance with formerly published population genetic analyses at the PAH locus, and with studies revealing the molecular basis of the phenotypic heterogeneity of PKU. The codon 281 mutation was more frequent in Croatia than previously observed in other populations.
Alleles↗
[Glutaric acidemia/glutaric aciduria I as differential chorea minor diagnosis].
Glutaracidemia/glutaraciduria type I is an acute or subacute neuropathic disorder of infancy or early childhood. The following symptoms characterize the clinical course: macrocephalus present at birth, cerebral atrophy revealed by CT or MRI scans, most striking in the frontal and temporal lobes, choreoathetosis and dystonia as neurological handicaps. The deficiency of glutaryl-CoA-dehydrogenase leads to glutaracidemia and glutaraciduria. It is reported on a three year old girl. The glutaraciduria is an important differential diagnosis to chorea minor.
Child, Preschool↗