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C J de Groot

Publications and source records attributed to C J de Groot.

84 records · Page 5Linked to original sources
PubMed1977

(2-Ethoxyethoxy)acetic acid: an unusual compound found in the gas chromatographic analysis of urinary organic acids.

An unknown acidic compound was detected in a number of urine samples from patients with a suspected metabolic disorder and some patients treated with chemotherapy. The structure of this compound has been characterized as (2-ethoxyethoxy)acetic acid, using a gas chromatography/mass spectrometry/computer system. The authentic compound was synthesized and compared with the unknown. Urinary (2-ethoxyethoxy)acetic acid is assumed to be formed endogenously from an exogenous precursor, probably 2-(2-ethoxyethoxy)ethanol.

Acetates↗
PubMed1975

Studies on the valine sensitivity in non-ketotic hyperglycinemia.

An oral loading test with L-valine (100 mg/kg body weight) in 3 patients with non-ketotic hyperglycinemia was accompanied by drowsiness and hyperreflexia of the patients. Metabolic studies revealed a slightly lower rate of disappearance of valine from blood in 2 of the patients. In a third patient, the curve was not different from controls. Gas chromatographic analysis for short-chain fatty acids in serum carried out during the valine loading test did not show increased concentrations. Urine collected during the valine loading test did not show excretion of N-acylglycine derivatives. As neither of the branched chain amino acid transaminases proved to be inhibited by glycine, inhibition by glycine of the uptake of valine by the tissues became likely. This uptake has been measured in rat liver slices. Glycine was found to be a competitive inhibitor of valine uptake, with a Ki of 4.9 mM. It is concluded that the tendency to a decreased rate of valine disappearance from blood in non-ketotic hyperglycinemia could be due to an inhibition of valine uptake by the high plasma glycine concentration. The relationship of the inhibited valine uptake in liver slices of rats with the clinical symptoms in non-ketotic hyperglycinemia patients after a valine load remains to be established.

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PubMedDate not supplied

Transcoronary and pulmonary vascular dynamics of endothelin-1 in heart transplant recipients.

BACKGROUND: Endothelin-1, a potent endothelium-derived vasoconstrictor peptide, has recently been shown to be elevated in heart transplant recipients and may be a participant in posttransplantation vasculopathy. METHODS: We measured peripheral venous endothelin-1 concentrations in eight heart transplant recipients and eight age- and gender-matched healthy controls. Subsequently, in 21 transplant recipients, right atrial, aortic, and coronary sinus plasma was obtained and endothelin-1 levels were measured. Potential correlations to donor and recipient age, cyclosporine levels, hemodynamic parameters, donor heart ischemic time, time from transplantation, and serum creatinine were examined. In eight more patients, right atrial levels of endothelin-1 were measured before and after endomyocardial biopsy to examine the effect of this procedure on endothelin-1 concentrations. RESULTS: Peripheral endothelin-1 concentrations were significantly higher in heart transplant recipients (45.6 +/- 1.8 versus 25.8 +/- 2.3, p < 0.001). Multiple regression analysis showed a significant correlation between right atrial endothelin-1 and pulmonary artery systolic pressure (r = 0.48), as well as serum creatinine (r = 0.52). No relation to blood pressure, right atrial pressure, pulmonary vascular resistance, recipient age, cyclosporine levels, or donor heart ischemic time was observed. In 11 patients, a 38% +/- 7% fall in endothelin-1 levels across the pulmonary bed was observed, suggesting extraction across the lung in these subjects. Nine patients had net release of endothelin-1 (95% +/- 26% rise) across the coronary vascular bed, whereas 12 patients showed net extraction (24% +/- 4% fall). Endomyocardial biopsy had no influence on endothelin-1 levels (prebiopsy: 48.3 +/- 1.7; postbiopsy: 42.3 +/- 2.34; p = Not significant). CONCLUSION: These findings suggest that endothelin-1 levels in transplant recipients may be influenced by renal function and may contribute to pulmonary hypertension. The significance of transcardiac release of endothelin in some patients is unclear: further studies are needed to determine the pathophysiologic significance of endothelin-1 in heart transplant recipients.

Adult↗