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F A Muskiet

Publications and source records attributed to F A Muskiet.

At least 145 records · Page 8Linked to original sources
PubMed1984

Measurement of plasma histamine by stable isotope dilution gas chromatography-mass spectrometry: methodology and normal values.

A new method for the determination of histamine by stable isotope dilution mass fragmentography is described. The method is specific, sensitive, and accurate, resulting in a within-day coefficient of variation of 4.1% and a day-to-day variation of 7.9%. It was shown that the first blood sample after a venipuncture can contain an artificially elevated plasma histamine concentration. Platelets contain about 7 pmol histamine/10(9) cells. Serum histamine was elevated about four times in comparison with plasma histamine. This phenomenon was mainly ascribed to degranulation of basophilic leukocytes by complement activation during blood clotting. Normal values for plasma histamine were (n = 25) 2.07 +/- 0.75 nmol/liter (mean +/- 1 SD), which is one of the lowest values reported up to now.

Adult↗
PubMed1984

Proton spin relaxation studies of fatty tissue and cerebral white matter.

Proton spin longitudinal (T1) and transverse (T2) relaxation and proton density studies were carried out on human fatty tissue and bovine white matter, both in the native state and after immersion in D2O. It is concluded that nuclear magnetic resonance signals from fatty tissue result mainly from methyl and methylene protons of hydrocarbons. No contribution from lipid protons could be detected for white matter, although it contains a high percentage of lipids. Imaging experiments, resulting in T1, T2, and proton density maps, support the results obtained with spectroscopic relaxation studies.

Adipose Tissue↗
PubMed1984

Meta-[I-131]iodobenzylguanidine uptake in a nonsecreting paraganglioma.

In a patient with a paraganglioma at the carotid bifurcation, intense uptake of meta-[I-131]iodobenzylguanidine (I-131 MIBG) in the tumor was found. There was no clinical or biochemical evidence for catecholamine secretion by the tumor, although analysis of the tissue revealed that catecholamine biosynthesis took place. We conclude that accumulation of I-131 MIBG may occur in a paraganglioma, but does not necessarily indicate endocrine activity of the tumor.

3-Iodobenzylguanidine↗
PubMed1984

Total polyamines and their non-alpha-amino acid metabolites simultaneously determined in urine by capillary gas chromatography, with nitrogen-phosphorus detector; and some clinical applications.

A capillary gas-chromatographic method with nitrogen-phosphorus detection is used here to simultaneously determine 1,3-diaminopropane, putrescine, cadaverine, spermidine, spermine, isoputreanine , putreanine , and N-(3-aminopropyl)-N'-(2-carboxyethyl)-1,4- diaminobutane in urine. After acid hydrolysis the compounds are isolated by adsorption onto silica gel and converted into their methyl-heptafluorobutyryl derivatives. We give quality-control data and age-dependent values for urinary excretion of these analytes by 76 apparently healthy controls. Circadian rhythmicity in the excretion of spermidine and (especially) isoputreanine was established and is discussed in the light of its implications for monitoring therapy of cancer. Investigation of menstrual-cycle-dependent diurnal variation in one normal woman showed no distinct, consistent fluctuations. We applied the method to monitor (by use of 24-h urine specimens) an uncomplicated, normally progressing pregnancy, a patient with metastatic melanoma being treated with cytostatic drugs, and (in more detail) the treatment of a patient with high-grade non-Hodgkin lymphoma.

Adolescent↗
PubMed1983

Capillary gas chromatographic profiling of total long-chain fatty acids and cholesterol in biological materials.

The profiling of total long-chain fatty acids and cholesterol in a variety of biological materials, using capillary gas chromatography with flame ionization detection, is described. The within-run precision and day-to-day precision for fifteen fatty acids and cholesterol in erythrocyte samples were investigated. Quantitative data on the analysis of amniotic fluid samples collected from women in the 30th to 38th week are given together with a correlation study on their lecithin/sphingomyelin and their palmitic acid/stearic acid ratios. In addition, the method was applied to lumbar cerebrospinal fluid, plasma, isolated leukemic blood cells and neuroblastoma tissue.

Amniotic Fluid↗
PubMed1983

Zinc in plasma and serum: influence of contamination due to the collection tubes.

The contamination caused by rubber stoppers of collection tubes preceding the determination of zinc in plasma and serum was investigated. The use of evacuated blood collection tubes (EBC-tubes), normally used for the collection of serum samples, could give rise to an average artificial increase of normal serum zinc concentrations of about 250%. Heparin containing EBC-tubes, used for the collection of plasma, and plain EBC-tubes of an experimental production appeared to be suitable for correct zinc determinations. There was no difference between the serum and plasma zinc levels of fifty volunteers.

Blood Specimen Collection↗
PubMed1983

Identification of three indolic compounds in a pigmented-melanoma cell-culture supernatant by gas chromatography-mass spectrometry.

In the supernatant of melanoma cell culture SK mel 25 three indolic compounds - 5-hydroxy-6-methoxyindole, 5-hydroxy-6-methoxyindolyl-2-carboxylic, and 6-hydroxy-5-methoxyindolyl-2-carboxylic acids - have been identified. The supernatants were extracted with ethyl acetate, derivatized, and analyzed by gas chromatography-mass spectrometry. The significance of this finding is discussed.

Cells, Cultured↗
PubMed1983

Gas-chromatographic determination of cholesterol sulfate in plasma and erythrocytes, for the diagnosis of recessive X-linked ichthyosis.

We describe a rapid method for determining cholesterol sulfate in plasma and erythrocytes. After its single-step isolation by means of anion-exchange chromatography cholesterol sulfate is hydrolyzed, trimethylsilylated, and determined by gas chromatography with flame ionization detection. 5 beta-Cholestan-3 alpha-ol sulfate is used as internal standard. The method enables simultaneous determination of dehydroepiandrosterone sulfate in plasma. We applied it for the diagnosis of seven patients with recessive X-linked ichthyosis. Concentrations are given for plasma and erythrocytes from four unaffected relatives of patients with X-linked ichthyosis, a patient with placental sulfatase deficiency, two patients with other types of ichthyoses, and 20 controls. The method may also be of use for the rapid isolation of other organic sulfates from biological material, as illustrated by a comparison of gas chromatograms of urine from a normal pregnant woman and that from a patient with placental sulfatase deficiency.

Adolescent↗
PubMed1983

Eumelanin (precursor) metabolites as markers for pigmented malignant melanoma: a preliminary report.

The pigmented form of malignant melanoma is a tumor with an exceptionally high production of melanin. It is therefore comprehensible that the precursors of melanin and/or their metabolites are excreted in elevated amounts during the course of this disease. Using gas chromatography--mass spectrometry we were able to identify five indolic compounds in the urine of melanoma patients: 5,6-dihydroxyindole (5,6DHI), 5-hydroxy-6-methoxyindole (5H6MI), 6-hydroxy-5-methoxyindole (6H5MI), and 5-hydroxy-6-methoxyindolyl-2-carboxylic (5H6MI2C) and 6-hydroxy-5-methoxyindolyl-2-carboxylic acids (6H5MI2C). For their quantitative mass fragmentographic analyses, deuterium-labeled analogs have been synthesized. The first experience with these measurements is presented.

Gas Chromatography-Mass Spectrometry↗
PubMed1981

Determination of N tau-methylhistamine in plasma and urine by isotope dilution mass fragmentography.

The determination in N tau-methylhistamine by gas chromatography-mass spectrometry is described using bis-heptafluorobutyryl derivatives and deuterium labelled N tau-methylhistamine as internal standard. A description of the synthesis of the internal standard, N tau-trideuteromethylhistamine, is given. Normal concentrations for plasma were 1.4 +/- 0.4 microgram/l (mean +/- 1 S.D., n = 10). The normal values for urine ranged from 60 to 280 microgram/24 h (n = 20). Five asthmatic patients showed above-normal plasma concentrations.

Asthma↗
PubMed1981

Identification of two Thormählen-positive compounds from melanotic urine by gas chromatography-mass spectrometry.

The isolation of two Thormählen-positive compounds from the urine of a patient with malignant melanoma and the elucidation of their structure by gas chromatography-mass spectometry is described. The compounds were isolated using a poly-N-vinylpyrrolidone column and separated by preparative thin-layer chromatography. After elution they were analyzed by gas chromatography and gas chromatography-mass spectrometry as their trimethylsilyl derivatives and after hydrolysis also as their tert.-butyldimethylsilyl derivatives. The results showed the main Thormählen-positive compound A to be the glucuronide of 5-hydroxy-6-methoxyindole, whereas the minor compound AX appeared to be the glucuronide of its isomer 6-hydroxy-5-methoxyindole.

Chromatography, Thin Layer↗
PubMed1981

A qualitative gas chromatographic analysis of substituted 5,6-dihydroxyindoles from the urine of patients with melanoma.

A qualitative gas chromatographic analysis of trimethylsilylated ethyl acetate extracts of melanotic urine revealed 5 indolic compounds, which have been identified as substituted 5,6-dihydroxyindoles. Ethyl acetate extracts of melanotic urines at pH 2.0 contained isomeric 5-hydroxy-6-methoxy and 6-hydroxy-5-methoxy-indolyl-2-carboxylic acids which were not separable under the conditions used. A careful hydrolysis of melanotic urine with a Helix pomatia preparation followed by extraction at pH 6.5 in a nitrogen atmosphere released 3 additional indolic compounds from their conjugated form. Using gas chromatographic-mass spectrometric analysis they were identified as 5-hydroxy-6-methoxy, 6-hydroxy-5-methoxyindole and 5,6-dihydroxyindole.

Chromatography, Gas↗
PubMed1981

Simultaneous determination of the four major catecholamine metabolites and estimation of a serotonin metabolite in urine by capillary gas chromatography of their tert-butyldimethylsilyl derivatives.

We have developed a routine capillary gas-chromatographic profiling method for simultaneous quantitative determination of the tert-butyldimethylsilyl derivatives of homovanillic acid, vanilmandelic acid, 3-methoxy-4-hydroxyphenylethylene glycol, and 3,4-dihydroxyphenylacetic acid and the estimation of 5-hydroxyindole-3-acetic acid in urine. The method is useful for diagnosis and followup of patients with functional tumors characterized by increased urinary excretion of metabolites originating from the metabolism of tyrosine and tryptophan--e.g., neuroblastoma, pheochromocytoma, carcinoid, and melanoma. It may also be applicable in pharmacokinetic studies of administered aromatic amino acids (parkinsonism, mental diseases, loading tests) and for diagnosis and followup of patients with inborn errors of metabolism that are characterized by organic aciduria (for instance, tyrosyluria and phenylketonuria).

Adolescent↗