Daniel Bongartz

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BACKGROUND Detection of renal artery stenoses (RAS) by means of duplex Doppler ultrasound with direct scanning of the main renal arteries is subject to numerous limitations. Using semiquantitative analysis of the Doppler curve, which can be recorded from intrarenal arteries, it is possible to detect RAS unaffected by the problems of direct Doppler scanning(More)
Urolithiasis is a very frequent finding in the Sudan, but stone analysis is not routinely performed in this country. It would, however, give important evidence for the metabolic basis of stone formation. We therefore set out to analyze urinary stones in 80 Sudanese patients (45 male, 35 female), 12 of whom where children. Fourier-transformed infrared(More)
OBJECTIVES To evaluate the relation of Tamm-Horsfall protein (THP) and citrate, both potent actors in the urinary stone forming process. METHODS Quantitative determination of THP in calcium oxalate (CaOx) stone-forming patients and healthy subjects was carried out according to the enzyme-linked immunosorbent assay method. RESULTS THP excretion in(More)
In this paper we present an improved method for the selective and sensitive determination of oxalate in different matrices such as urine, plasma, and food. The method uses ion chromatography for the separation of anions. To overcome problems with interfering matrix-anions, colourings, and macromolecules, we used an inline enzyme-reactor (ER) containing(More)
OBJECTIVE Five methods for oxalate analysis in urine are compared with respect to reliability, accuracy, and practicability. RESULTS Suppressed and unsuppressed ionchromatography, as well as the enzymatic Sigma-Kit, achieve low coefficients of variation for the within-batch imprecision (1.1-8.0%) and between-day imprecision (1.6-7.2%). The results of(More)
A 46-year old female nursing sister was admitted to three different hospitals because of blood pressure crises of 300/150 mmHg which occurred up to six times a day. The rises in blood pressure were accompanied by headache, tachycardia and outbreaks of sweating. Raised catecholamine concentrations were repeatedly measured in the 24-hour urine and in the(More)
To understand the genesis of urinary stones different crystallization models have been developed to simulate the crystallization processes that occur at the beginning of the stone formation. In this study a laser probe working on the principle of the measurement of back-scattered light was mounted on a batch crystallization model, in which calcium oxalate(More)
Quercetrin, quercetin and chlorogenic acid were measured in urine or in drugs by combination of boronic acid affinity chromatography and HPLC. Simple reversed-phase HPLC with UV detection was used to determine quercetrin in five different Solidago virgaurea drugs. For determination of quercetrin in human urine immobilized boronic acid was applied for sample(More)
Hyperoxaluria was reported to induce renal damage, probably due to toxic effects on renal tubules. Such tubular damage might be expressed by an increase in urinary excretion of marker enzymes such as N-acetyl-β-d-glucosaminidase (NAG). We set out to examine a possible relationship between the excretion of NAG and that of urinary lithogenic and(More)
INTRODUCTION Efficacy of ESWL treatment can be evaluated by determining the number and size of urinary stone fragments. However, the available methods for classification of stone fragments are inaccurate. Therefore, a method for semi-automatic determination of fragment size and number after ESWL was developed. METHODS Artificial struvite stones(More)