[A new method for the evaluation of stone fragmentation after ESWL]. / Eine neue Methode zur Evaluation der Steinfragmentation nach ESWL.

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 (BON[N]-STONES) were disintegrated with a lithotriptor (Siemens, Lithostar plus) by application of 50 and 200 shock waves at 19 kV. The stone fragments were collected and pre-sorted on cascade sieves. Pictures taken of the fractions were digitalized and the images optimized in edge sharpness, contrast, and colour depth using an image processing software. Finally, the pixel number of each fragment was determined and the real area was calculated. Fragment size and volume were then depicted by frequency of occurrence in a histogram. RESULTS: Fragments with a diameter ranging from 0.3 - 5 mm could be determined by the system described. About 2,000 - 3,600 fragments were generated in this size range from the artificial struvite stones. With low shock-wave application, a considerable number of fragments larger than 2 mm could be observed. By increasing the impact to 200, more than 90 % of the stone volume was found in fragments smaller than 2 mm (previously 50 %). CONCLUSION: The system described enables a qualitative and quantitative description of stone fragmentation after ESWL not achieved thus far.

Direct measurement of calcium oxalate nucleation with a laser probe.

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 nucleation was induced by titration of an artificial urine with ammonium oxalate. With the laser probe the particle numbers and particle size distributions in the range from 1-250 microm can be measured in a single experiment. Measurement is performed directly at the place of crystal development and, therefore, falsification of the results (by dilution, mechanical transport or isolation, temperature gap, multiple measurements, mathematical calculations after indirect measurements, etc.) is prevented. In a basic urine, containing 7.5 mmol/l calcium (4.13 mmol/l free calcium), nucleation of calcium oxalate appears at a concentration of 0.58 mmol/l oxalate. At the start of nucleation the particle size rises to 7 microm. After addition of citrate and magnesium in concentrations up to 12 mmol/l the metastable limit is clearly shifted up to 1.50 mmol/l oxalate. Both findings are in good agreement with the literature. The laser crystallization model has proved to be useful for the testing of inhibitors and promoters of urinary stone formation.

Tamm-Horsfall protein excretion and its relation to citrate in urine of stone-forming patients.

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 24-hour urine samples of CaOx stone-forming patients was significantly reduced compared with healthy subjects. A significant correlation exists between the concentration of THP and citrate in the stone-forming group, as well as in the group of healthy subjects, and for the 24-hour excretion, this correlation persists in the group of CaOx stone-forming patients. CONCLUSIONS: Decreased THP and citrate excretions were found in CaOx stone-forming patients. They indicate a tubular dysfunction of the distal section.

N-acetyl-beta-D-glucosaminidase excretion in healthy children and in pediatric patients with urolithiasis.

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-beta-D-glucosaminidase (NAG). We set out to examine a possible relationship between the excretion of NAG and that of urinary lithogenic and stone-inhibitory substances by analyzing 24-h urine specimens from 56 children with urolithiasis and 25 healthy children with normal renal function and without a history of urolithiasis. The NAG excretion was higher in patients with urolithiasis (3.5 +/- 0.51 U/g creatinine) as compared with healthy subjects (1.33 +/- 0.14 U/g creatinine, P < 0.05). A positive correlation between NAG and oxalate excretion was observed in female patients (r = 0.56: P < 0.01). In conclusion, the increase in urinary NAG in children with urolithiasis might express renal tubular damage. It seemed, however, not to be specifically related to the excretion of a single lithogenic substance.

Mineral composition of renal stones from the Sudan.

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 spectroscopy was used for stone analysis. As is known from other countries, calcium oxalate (CaOx) stones were the most frequent, with 68.7% of all stones in adults and 43.7% of childhood stones. Uric acid and uric acid dihydrate stones were more often seen in adults (13.2%) than in children (4. 1%). Ammonium urate stones are common in the Sudan, especially in children (32.9%), which is typical for underdeveloped countries. Infectious stones (struvite and carbonate apatite) were more often found in women (7.0%) and in children (5.3%) than in men (1.4%). Brushite stones were seldom seen and cystine stones did not occur.

Simulation of a pheochromocytoma--Munchausen syndrome.

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 blood. The diagnosis of pheochromocytoma could therefore be regarded as confirmed. The investigations to establish the localization (including MIBG scintigrams carried out several times) showed negative results. Octreotide scintigraphy finally revealed a raised concentration of nuclides in the right adrenals. Selective venous blood samples showed markedly raised concentrations of adrenaline and noradrenaline in all regions investigated. After removing the right adrenal, which was of normal histological appearance, there was an improvement for six months. Afterwards, up to six blood pressure crises per day were observed once more. Fresh determination of catecholamines at various levels demonstrated the highest concentrations in the left iliac vein. It was then shown that the patient injected catecholamines intravaginally even during the angiographic investigation. A search of the patient s room revealed several ampoules containing noradrenaline and adrenaline as well as syringes and needles. - This case shows that in clinical pictures with typical clinical symptoms and negative results of repeated investigations a factitious disorder must be considered in terms of differential diagnosis especially when female patients with medical knowledge who have ready access to drugs are involved with a history comprising several stays in hospital which have not produced any clarification of their condition.

Renal artery stenosis: evaluation with colour duplex ultrasonography.

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 of the renal arteries. METHODS: Both angiography of the renal arteries and colour duplex ultrasonography (US) of the intrarenal vessels (interlobar arteries) were performed in 214 patients (53.2 +/- 14.1 years) with severe arterial hypertension. Angiography was used as 'gold standard' in the diagnosis of RAS and the Doppler results were compared with the subsequent findings on angiography. At angiography, the reduction of diameter > 70% was assessed as haemodynamically effective RAS. For the duplex Doppler diagnosis of RAS the following parameters were calculated: (a) resistive index (RI) of each kidney, and (b) side-to-side differences of the resistive indices (delta RI) between the right and left kidney. RESULTS: Angiography demonstrated 59 RAS (> 70%) in 53 patients, including six with bilateral RAS. By means of duplex US we found a significant difference of RI between kidneys with RAS (0.48 +/- 0.11) and without RAS (0.63 +/- 0.08; P < 0.001). In addition, a significant difference of the delta RI was noted in patients with RAS (24.4% +/- 12.5%) and the controls without RAS (3.6% +/- 2.7%). Using a combination of both RI and delta RI, threshold values of RI = 0.45 resp. delta RI = 8% yields a sensitivity of 92.5% and a specificity of 95.7% in the detection of haemodynamically effective RAS. CONCLUSIONS: Colour duplex US with calculation of the RI and delta RI of intrarenal arteries is a valuable non-invasive test assessing the haemodynamic effects of a RAS. Low costs and safety support the use of the Doppler technique in screening for renovascular disease.

An improved HPLC-enzyme-reactor method for the determination of oxalic acid in complex matrices.

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 immobilised oxalate oxidase, which converts oxalate to hydrogen peroxide. Hydrogen peroxide was analysed with high sensitivity by amperometric detection. The determination limit for the HPLC-ER method was 1.5 mumol/1, the mean recovery in urine was 102%. The evaluation in a urinary matrix achieved C.V. values from 2.2% to 6.7% for the within-run precision and C.V. values from 3.7% to 8.6% for the between-batch precision. The results of the new method were statistically equivalent to those obtained by enzymatic kits. We present first results of the HPLC-ER method, when applied to body fluids and food analysis.

The direct determination of urinary oxalate by non-suppressed ion chromatography.

In this paper we describe a simple ion chromatographic method for determination of oxalate in urine. Acidified urine was diluted 1:2 with 0.03 mol/l benzidine hydrochloride in 0.3 mol/l boric acid to precipitate sulphate. The supernatant was passed through a C18-cartridge and 100 microliters of eluant were injected into an ion chromatographic system. Oxalate was measured by nonsuppressed conductivity detection. The detection limit for urinary oxalate was 0.05 mmol/l. The recovery for spiked urine samples was 101.5% with a CV of 4.5%. The within- and between-assay coefficients of variation were less than 4.5% and 2.5%, respectively. We found the results obtained by this method to be statistically equivalent to an enzymatic assay and a different ion-chromatographic method.

[Spontaneous portasystemic shunt in liver cirrhosis: imaging with color-coded duplex ultrasonography]. / Spontane portosystemische Shunts bei Leberzirrhose: Darstellung durch farbkodierte Duplexsonographie.

PURPOSE: To demonstrate the usefulness of B-scan ultrasonography and color Doppler ultrasonography (CCDS) in the diagnosis of lumbal and splenorenal collateral veins in patients with liver cirrhosis. METHOD: 46 patients with histologically proven liver cirrhosis were examined by means of B-scan ultrasonography. CCDS was used to demonstrate the vascular character of mass-like lesions or tortuous tubular structures. Esophageal varices were demonstrated in 23 (50%) and ascites in 6 patients (13%). RESULTS: In 5 out of 46 patients (10.9%) we demonstrated lumbal and splenorenal portosystemic venous collaterals by B-scan- and CCDS. In 2 patients localized venous collaterals were demonstrated. No ascites was found in patients with accessory portosystemic shunts. CCDS showed the patency of these spontaneous portosystemic shunts. CONCLUSION: In patients with chronic liver disease CCDS is a noninvasive method to demonstrate spontaneous portosystemic shunts due to portal hypertension. The method provides information concerning patency and flow direction of the collateral veins.

[Current information on the composition and breed distribution of urinary stones in dogs]. / Aktuelle Daten zur Zusammensetzung und Rassenverteilung der Harnsteine von Hunden.

5706 canine urinary stones were analyzed by means of infrared spectroscopy from 1984-1996. The stones were sent in together with epidemiologic data (breed, age, sex, localisation of the stones, type of stone removal, stone frequency etc.) by more than 800 veterinarians from Germany, the Netherlands, Austria, and Switzerland. Irrespective of stone type, urinary stones were observed in almost all breeds, but small breeds like dachshound, poodle, terrier, schnauzer, and pekingese have a higher tendency to form stones. With 59.5% struvite is the most frequent stone type, followed by cystine with 15.5%. Cystine stones are becoming less frequent during the observation time, whereas the share of calcium oxalate (14.2%) and ammonium urate (6.0%) stones remains unchanged. The latter stone types are found predominantly in specific breeds. The stone formation appears predominantly at the age of 7. Male dogs form stones twice as often as female dogs. 98% of the stones were located in the lower urinary tract. About 90% of the urinary stones required surgical treatment.

Measurement of urinary oxalic acid: a comparison of five methods.

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 these methods are comparable and the mean recovery rate ranges between 99.7% and 100.9%. The enzymatic Boehringer-Kit gives higher CV (3.1-9.5%) and the results are lower than those obtained by the methods mentioned above; the recovery rate is sufficient (92.4%). CONCLUSION: The handling of the chromatographic methods is very easy, whereas the enzymatic methods require more manual work. In relation to sample throughput, charges for the enzymatic methods are about twice as high as for the chromatographic methods. In respect to reliability and accuracy, the chromotropic acid method cannot be recommended (recovery rate 68%).

Laparoscopical marsupialization of symptomatic post-transplant lymphoceles.

Post-transplant lymphoceles after kidney transplantations occur with an incidence between 2 and 15%. In the last two years we observed four patients with symptomatic lymphoceles. After an infection or urinoma had been ruled out all cases were operated on laparascopically. All goals of open surgery in lymphoceles were achieved by this minimally invasive technique within an operating time between 40 and 70 min. No complications or recurrences occurred during a mean follow-up period of 17.8 months. Symptomatic post-transplant lymphocele is a rare event and represents an ideal indication for laparoscopic marsupialization.

Selective extraction of quercetrin in vegetable drugs and urine by off-line coupling of boronic acid affinity chromatography and high-performance liquid chromatography.

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 pretreatment. this procedure leads to a determination limit of 0.01 micrograms/ml with a recovery rate of 95.3%. The first results using this method for quercetrin pharmacokinetics are presented.

Medullary nephrocalcinosis: sonographic findings in adult patients.

Medullary nephrocalcinosis occurs in various diseases as a non-specific renal manifestation. We present 5 patients (hypophosphataemic rickets, type 1 renal tubular acidosis, primary hyperparathyroidism, hypercalcaemia of unclear origin, chronic renal insufficiency requiring dialysis) in whom a medullary nephrocalcinosis was demonstrated by means of sonographically detectable changes in the renal medulla region. The sonographic appearance of medullary nephrocalcinosis is characterized by detection of echo-enhanced structures in the region of the renal pyramids. The presence of a medullary nephrocalcinosis can generally be confirmed with adequate reliability on the basis of sonographic findings and characteristic clinical pictures. In individual cases it is difficult to distinguish between medullary nephrocalcinosis and renal calyx calculi.