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H G Tiselius

Publications and source records attributed to H G Tiselius.

At least 109 records · Page 6Linked to original sources
PubMed1985

Measurement of the risk of calcium oxalate crystallization in urine.

The risk of calcium crystallization (CaOx-CR) in urine was analyzed by means of crystal counting following standardized addition of oxalate. CaOx-CR was determined in 24 h urine samples from 21 stone formers and 26 normal subjects following dilution of urine to a creatinine concentration of 5 mumol per ml. The mean (+/- SD) CaOx-CR was in stone formers 1.42 +/- 0.57 and in normal subjects 1.29 +/- 0.40. CaOx-CR was also analyzed in 16 fresh urine samples diluted to 80 per cent of the original concentration whereby values between 0.36 and 3.6 were recorded. There was a good correlation between CaOx-CR and estimates of the ion-activity product of CaOx, both in urine diluted to 5 mumol of creatinine per ml and in 80 per cent diluted urine. It ist suggested that the method described is of value for evaluation and follow up of patients with CaOx urolithiasis.

Calcium Oxalate↗
PubMed1984

A method for quantitative wet chemical analysis of urinary calculi.

We describe a simple method for quantitative chemical analysis of urinary calculi requiring no specialized equipment. Pulverized calculi are dried over silica gel at room temperature and dissolved in nitric acid, which was the only effective agent for complete dissolution. Calcium, magnesium, ammonium, and phosphate are then determined by conventional methods. Oxalate is determined by a method based on the quenching action of oxalate on the fluorescence of a zirconium-flavonol complex. Uric acid, when treated with nitric acid, is stoichiometrically converted to alloxan, which is determined fluorimetrically with 1,2-phenylenediamine. Similarly, cystine is oxidized by nitric acid to sulfate, which is determined turbidimetrically as barium sulfate. Protein is determined spectrophotometrically as xanthoprotein. The total mass recovery of authentic calculi was 92.2 +/- 6.7 (SD) per cent. The method permits analysis of calculi as small as 1.0 mg. Internal quality control is performed with specially designed control samples.

Cations↗
PubMed1984

Effects of sodium urate and uric acid crystals on the crystallization of calcium oxalate.

Crystallization of calcium oxalate in the presence of uric acid and sodium urate crystals was analyzed in a metastable crystallization system containing calcium chloride and sodium oxalate (A), in urine highly supersaturated with respect to calcium oxalate (B), and in urine with a high level of metastable supersaturation (C). In system A uric acid crystals in concentrations up to 11.4 mMol/l did not affect calcium oxalate crystallization, neither did sodium urate during the first 6 h in concentrations below 5 mMol/l. In system B neither uric acid nor sodium urate crystals affected calcium oxalate crystallization. However, an increased rate of crystallization was observed with both uric acid and sodium urate in system C, but the effect was less pronounced than with calcium oxalate seed. Urine pre-treated with sodium urate and subsequently analyzed in system A in a concentration of 2%, gave a slightly lower inhibition of calcium oxalate crystal growth. Concerning the crystal size distribution in the same system, larger crystals were observed in several urines pre-treated with uric acid and sodium urate.

Calcium Oxalate↗
PubMed1984

Studies on crystalluria in calcium oxalate stone formers.

The excretion of calcium oxalate and calcium phosphate crystals was studied in fractionated 24 h urine from 7 men with recurrent calcium oxalate stone disease, both before and during daily administration of 5 mg bendroflumethiazide. Urinary calcium, oxalate, magnesium, citrate, phosphate, pH, and inhibition of calcium oxalate crystal growth rate were analyzed in all samples. Exclusively calcium oxalate crystals were found in 30 per cent of the samples, all with a pH below 6.25, whereas calcium phosphate was the crystal type encountered in urine with a pH above 6.50. Bendroflumethiazide decreased the volume of calcium phosphate but not of calcium oxalate crystals. During the period of observation there was no correlation between calcium oxalate supersaturation and calcium oxalate crystal volume, but a relationship was demonstrated between calcium phosphate supersaturation and calcium phosphate crystal volume.

Adult↗
PubMed1984

Variations in urine composition during the day in patients with calcium oxalate stone disease.

The diurnal variations of urine composition with respect to calcium, magnesium, oxalate, citrate and inhibition of calcium oxalate crystal growth were studied in patients with recurrent calcium oxalate stone disease. There was considerable variation in the excretion of the different urine constituents with meal-related peaks, which was most pronounced for calcium. The highest concentration of calcium was observed before noon, and between 7 and 11 p.m. Oxalate concentration was highest between 6 and 10 a.m. Consequently, the highest levels of supersaturation were recorded between 6 and 10 a.m., and 6 and 10 p.m. The inhibition index was at the highest level during the first morning hours and could be important in counteracting crystal growth at that time. The risk of exceeding a theoretical formation product of calcium oxalate appeared to be low, with a 24-hour urine volume more than 2,000 ml.

Adult↗
PubMed1984

Biochemical effects in patients with calcium oxalate stone disease during combined treatment with bendroflumethiazide and magnesium oxide.

Thirteen patients with calcium oxalate stone disease were treated with 2.5 mg bendroflumethiazide and 200 mg magnesium oxide twice daily for 1 year, and the effects on serum and urine constituents were evaluated. Serum magnesium and potassium decreased, whereas urate increased during treatment. The association of decreased urinary calcium and increased urinary magnesium resulted in a reduced Ca/Mg quotient and apparently a lower risk of forming urine supersaturated with calcium oxalate. Combined treatment with a thiazide and magnesium appears to alter the composition of urine in a way that might be more favourable than treatment with either substance alone.

Adult↗
PubMed1984

Clinical experience with long-term bendroflumethiazide treatment in calcium oxalate stone formers.

Bendroflumethiazide was administered to 85 patients (62 men, 23 women) with recurrent calcium oxalate stone disease. Side effects leading to interrupted treatment were observed in 26 (31%) of the patients. Fifty-nine (40 men, 19 women) remained on treatment for a mean (+/- SD) period of 3.7 +/- 1.0 years, and 21 reported late side effects. Twenty patients were given 2.5 mg bendroflumethiazide daily (Group A), 27 were given 2.5 mg twice daily (Group B), and 12 were given 5 mg once daily (Group C). Eight patients (14%) formed new stones and another two demonstrated stone growth during treatment. A beneficial effect on stone formation was observed in Groups B and C but not in Group A. Patients who failed to respond to treatment had a pre-treatment stone formation rate of 0.74 stones per year compared with 0.22 in those who did not form new stones. Those with recurrence during treatment had a lower citrate excretion than other patients. No effect on urinary citrate was recorded during treatment, and long-term treatment with bendroflumethiazide did not affect oxalate excretion.

Adult↗
PubMed1984

A simplified estimate of the ion-activity product of calcium phosphate in urine.

A computerized program was used to calculate the activities of the calcium, phosphate, and hydrogen phosphate ions. The most important determinants for ion-activity products of calcium phosphate and brushite were calcium, phosphate, citrate, urine volume, and pH. These urine variables were used to derive indices corresponding to ion-activity products of calcium phosphate (AP[CaP] index) and calcium hydrogen phosphate (AP[Bru] index). Factors were given to adapt these indices to collection periods shorter than 24 h. Relationships between the AP(CaP) index and ion-activity products of hydroxyapatite and octacalcium phosphate were also formulated. With urine electrolytes within the normal range a very good correlation was obtained between these indices and corresponding ion-activity products. The coefficient of correlation was better than 0.99. The presented indices might be useful in the evaluation of patients with renal calcium stone formation.

Calcium Phosphates↗
PubMed1984

Diurnal variation of urine composition in calcium oxalate stone disease during treatment with bendroflumethiazide.

Urine samples, collected hourly between 6.00 and 23.00 h and in one single night fraction, were analyzed for calcium (Ca) and magnesium (Mg) before and during daily administration of 5 mg bendroflumethiazide to 13 Ca-oxalate (CaOx) stone formers. In some of them urinary oxalate (Ox), citrate and sodium were analyzed as well. Bendroflumethiazide was administered in divided doses to 7 and in a single dose to 6 patients. After 4-8 weeks of treatment urinary Ca decreased by approximately 25% in both groups and the reduction was evenly distributed over the day. The reduction of the Ca/Mg quotient and the CaOx risk index was most pronounced following meals. The AP(CaOx) index, an estimate of the CaOx ion activity product, was favorably reduced. No important differences were recorded for the different types of bendroflumethiazide administration and thus one single dose might be equally as efficient as two divided doses.

Adult↗
PubMed1983

Urinary excretion of urate in patients with calcium oxalate stone disease.

The diurnal variation in excretion and concentration of urinary urate was studied in 31 patients with calcium oxalate stone disease. Urate excretion was highest during the day-time, decreased in the evening and was low during the night. Meal-related peaks were observed. The concentration of urate reached the highest levels during the morning hours and, attributable to a low pH in morning urine, most samples were at this time super-saturated with respect to uric acid. In addition, many urines appeared to be at high risk of exceeding the uric acid formation product. Concerning the ion-activity product of sodium urate, supersaturated samples were frequently found, but the risk of exceeding the formation product for sodium urate at a normal urate excretion was apparently low.

Calcium Oxalate↗
PubMed1983

Urine composition following jejunoileal bypass.

The urinary excretion of oxalate, calcium, citrate, magnesium, urate and creatinine and the inhibition of calcium oxalate crystal growth were determined in 30 patients operated with three different types of jejunoileal bypass. In addition the ion-activity products of calcium oxalate and calcium oxalate saturation were calculated. 15 of the patients had formed urolithiasis postoperatively. The patients were investigated on an out-patient basis with their ordinary diet. All patients had hyperoxaluria. The oxalate excretion did not seem to decrease with time after operation. The patients operated with a biliointestinal shunt had a significantly higher excretion of oxalate than those with the other two types of operation, indicating that variations in the anatomy of the small intestine after jejunoileal bypass might result in different absorption of oxalate or oxalate precursors. Urinary oxalate, calcium oxalate saturation and ion-activity products were higher whereas the excretion of calcium, magnesium and citrate was lower in patients than in controls. The urine volumes, excretion of creatinine and urate and inhibition of calcium oxalate crystal growth were equal in patients and controls. Analogous urine composition was found in patients both with and without urolithiasis with the exception of a higher magnesium excretion observed in stone formers.

Adult↗
PubMed1983

Different estimates of the risk of calcium oxalate crystallization in urine.

Different mathematical expressions of urinary calcium, oxalate, magnesium, citrate and urine volume (V), formulated in order to reflect supersaturation with respect to calcium oxalate, were compared with the computer-calculated ion-activity product of calcium oxalate (APCaOx). A good correlation (r = 0.99) was demonstrated for the following two simplified relationships and APCaOx:Ca0.71 X Ox and (Ca0.71 X Ox)/V1.2. The correspondence between Ca/Mg quotients and APCaOx was generally less satisfactory.

Calcium Oxalate↗
PubMed1983

Low-oxalate, low-fat dietary regimen in hyperoxaluria following jejunoileal bypass.

Previous studies have shown that the severity of enteric hyperoxaluria can be reduced in hospitalized patients who receive a diet low in oxalate and fat. Little is known of the value of such a diet in the patients' home conditions. Ten patients with hyperoxaluria (greater than 0.45 mmol/24 h) following jejuno-ileal bypass were therefore studied while on their ordinary diet and also on a diet with low-oxalate, low-fat content. The mean urinary excretion of oxalate decreased during the dietary treatment from 1.1 to 0.7 mmol/24 h. The diet was demanding, though not unfeasible for the patients. Careful and regular dietary information, preferably by a dietitian, is recommended in such cases.

Adult↗