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Biomedical subjects

B G Danielson

Publications and source records attributed to B G Danielson.

At least 73 records · Page 4Linked to original sources

Intestinal oxalate and calcium absorption in recurrent renal stone formers and healthy subjects.

The fractional intestinal absorption of oxalate and calcium was investigated by isotope techniques in 20 normal subjects and in 12 idiopathic calcium oxalate stone formers. The greatest amount of 14C-oxalate was excreted during the first six hour period in controls as well as in stone formers. The stone formers had a greater intestinal uptake of oxalate (11 +/- 5.1%) than the controls (6.2 +/- 3.7%; p less than 0.01). There was no significant relationship between the fractional absorption of oxalate and the total urinary oxalate excretion. The stone formers also had a higher fractional uptake of calcium compared to the controls (55 +/- 11% vs. 47 +/- 9.1%; p less than 0.05). There was a positive relationship (r = 0.47) between the urinary excretions of calcium and oxalate in the stone formers. During these conditions no correlation could be demonstrated between the fractional absorptions of oxalate and calcium, neither in the stone formers nor in the controls. In conclusion, patients with recurrent formation of calcium oxalate containing stones appear to have an enhanced intestinal uptake of both oxalate and calcium. This disturbance could be of primary pathogenic importance for their stone forming propensity.

Adult↗

Dietary habits in renal stone patients compared with healthy subjects.

The dietary habits of renal calcium stone patients were investigated both by dietary history and by 4-day food records and compared with the dietary habits of control subjects, matched on the basis of age, sex, social and professional status. The method using 4-day records seemed to be more precise, judged by the correlation to the urinary output of nutrients. There was no difference in the daily intake of major nutrients between stone formers and controls, but a higher ingestion of vitamin C in controls and a larger consumption of alcohol among stone formers. In contrast to some epidemiological evidence, there were no significant differences in consumption of animal protein when stone formers were matched for social class. Despite a similar total intake of calcium, the stone formers excreted more calcium in the urine, probably reflecting a higher intestinal absorption of calcium. There seem to be only marginally different dietary habits between stone formers and carefully matched control subjects. Differences in the urinary output of minerals and electrolytes are mainly due to variations in gastrointestinal uptake.

Adult↗

Aluminum removal with hemodialysis, hemofiltration and charcoal hemoperfusion in uremic patients after desferrioxamine infusion. A comparison of efficiency.

In order to compare the effectiveness of aluminum removal in uremic patients during extracorporeal treatment, 17 patients with endstage renal failure were given a desferrioxamine infusion of 40 mg/kg body weight after an ordinary dialysis treatment. Forty-eight hours later 7 patients were treated with hemodialysis, 6 with hemofiltration and 4 with a combination of hemodialysis and hemoperfusion. The clearance of aluminum was measured at different intervals. It was found that the aluminum clearance was 75 +/- 18 ml/min in hemofiltration compared to 30 +/- 10 ml/min in hemodialysis (p less than 0.001). A combination of hemodialysis and hemoperfusion with a charcoal column containing 100 g activated charcoal in series gave a total aluminum clearance of 56 +/- 11 ml/min. The total amount of aluminum in the ultrafiltrate after hemofiltration was found to be approximately 3 times as high (1,728 +/- 156 micrograms) as the total amount of aluminum in the hemodialysis water that had passed a single pass system during a 4-hour dialysis (576 +/- 104 micrograms). Our results indicate that hemofiltration or a combination of hemodialysis and hemoperfusion should be used to remove aluminum in patients with signs of severe aluminum accumulation such as encephalopathy or painful bone disease, because these methods are 2-3 times as effective as ordinary hemodialysis. In patients where aluminum has been accumulated but no severe symptoms occur hemodialysis gives a significant clearance of the aluminum desferrioxamine complex.

Aluminum↗

Intestinal absorption of oxalate and calcium in patients with jejunoileal bypass.

Jejunoileal bypass (JIB) has been widely performed for treatment of excessive obesity. Formation of calcium oxalate stones is a common side effect. Since, under physiological conditions, the intestinal absorption of calcium and that of oxalate are interrelated, intestinal oxalate and calcium absorption were measured in the present study by isotope techniques in 19 JIB patients and 20 healthy controls. The JIB patients showed pronounced hyperoxaluria and markedly increased absorption of oxalate, with a urinary excretion of 14C-oxalate of 29 +/- 19% (controls 6.2 +/- 3.7%; p less than 0.001). There was a strong correlation between the intestinal absorption and urinary excretion of oxalate in the JIB patients (r = 0.72; p less than 0.001). Furthermore, their oxalate kinetics was altered, with continued urinary excretion of 14C-oxalate for up to 48 hours. The JIB patients also had reduced calcium absorption (36 +/- 9.1% vs. 47 +/- 9.0%; p less than 0.001) and patients with malabsorption of calcium and low urinary calcium had the highest intestinal absorption and urinary excretion of oxalate. It is concluded that hyperoxaluria in JIB patients is due to a significant extent to hyperabsorption of oxalate.

Adult↗

The relation between urinary tract infections and stone composition in renal stone formers.

During a seven-year period (1975-1981) a total of 1325 patients hospitalized for stone disease were studied as to the occurrence of positive urine cultures. Urinary stones from 535 surgically treated patients were analyzed with infrared spectrophotometry and the relationships between stone composition, level of surgery and bacteriological strains were studied. Positive urinary cultures were found in 34% of the surgically treated patients and in 21% of those not operated upon. Among the surgically treated patients with urinary tract infection (UTI) E. coli was the most frequent microorganism (35%), followed by Proteus (28%). Patients with Proteus infection had the highest frequency of UTI episodes, most of which occurred before hospitalization. There was a higher frequency of magnesium ammonium phosphate (MAP) calculi among patients with Proteus infection than among those with non-Proteus infection, in whom no difference in stone composition was found. Patients infected with E. coli had more phosphate-containing stones (CaP+MAP) than non-infected patients. The highest frequency of oxalate calculi (CaOx+CaOx/CaP) was found among patients without infection. No E. coli infections were seen in male patients with CaP and MAP calculi. MAP stones were most often found in the kidney and oxalate stones in the ureter.

Calcium Oxalate↗

Four years' experience of long-term hemofiltration in a Swedish center.

Thirty patients with end-stage renal disease were switched from maintenance hemodialysis to postdilution hemofiltration and observed for long-term effects. The study comprised totally 496 months of hemofiltration. Uremic and biochemical control was similar in the hemofiltration and in the hemodialysis period. Of the small molecules, only serum creatinine showed slight increase after 3 months. No other significant changes in creatinine, serum urea or potassium levels were associated with long-term hemofiltration. During each hemofiltration session there was significant decrease of serum parathyroid hormone (PTH) and serum beta 2-microglobulin, but over the first 8 months of hemofiltration the beta 2-microglobulin values did not fall, and significant PTH reduction was found only after 12 months. Although uremic control was similar with both methods, there were fewer complications of hemofiltration, which was preferred by the patients. Because it is currently more expensive, however, hemofiltration should be reserved for patients with dialysis related problems, that are not helped by other changes in the dialysis technique, such as sequential ultrafiltration changes in the dialysis membranes and in the dialysis buffer from acetate to bicarbonate.

Female↗

Outcome of continuous arteriovenous haemofiltration (CAVH) in one centre.

Continuous arteriovenous haemofiltration (CAVH) has been adopted as the treatment of choice for acute renal failure (ARF) in critically ill patients in the intensive care units of Uppsala University Hospital since 1982. To know the outcome of CAVH during the last one and a half year this retrospective study was done on those patients seen in July 1987-December 1988. Forty patients aged 2 months-84 years (mean 57 years) were included. Treatment duration was 1-31 days (mean 10 days, patients with treatment duration less than 24 h were excluded). The majority of ARF causes were due to major surgery because there are two big cardiothoracic and vascular surgical centres with a high turnover in this hospital. In this study CAVH was found useful in the management of ARF in critically ill patients within the limits of its capacity of urea clearance. There is a notable improvement in the number of survivors in this study (55%) when this is compared to a previous study (45%) in a similar group of patients and in the same centre.

Acute Kidney Injury↗

Continuous arteriovenous hemofiltration in the treatment of 100 critically ill patients with acute renal failure: report on clinical outcome and nutritional aspects.

The clinical outcome for 100 consecutive patients with multiorgan failure including acute renal failure (ARF) was studied. Fifty-eight of the patients had acute renal failure due to complications during and after major surgery. Seventy-three of the patients had a urine output of less than 400 ml/24 hours. The majority of the patients also had complications such as septicemia or respiratory insufficiency and required vasopressor infusions. All patients were treated with continuous arteriovenous hemofiltration (CAVH). The duration of the CAVH treatment varied between a few hours and 90 days, with a mean of 8 days. The mean ultrafiltration volume per 24 hours was, on the average, 12 liters. CAVH resulted in adequate uremic control in 89 cases, but additional treatment with intermittent hemofiltration was necessary in 11 patients. The total survival rate was 45% including survival rates as high as 54% in patients with ARF complicating abdominal aortic surgery. Only three patients were referred for chronic dialysis therapy. In a subgroup of 17 patients with ARF complicating abdominal aortic surgery the nutritional aspects during CAVH were studied. It is concluded that during CAVH therapy it is possible to give adequate nutritional support even to hypercatabolic and anuric patients.

Acute Kidney Injury↗

Pharmacokinetics of intravenous cefuroxime during intermittent and continuous arteriovenous hemofiltration.

The pharmacokinetics of cefuroxime were determined in ten patients during intermittent hemofiltration (IHF) and in three patients during continuous arteriovenous hemofiltration (CAVH). All patients received a bolus dose of 1.5 g of cefuroxime intravenously and the concentrations of cefuroxime in serum and ultrafiltrate were followed during the hemofiltration period and up to 16 hours after injection of cefuroxime. During IHF the mean terminal half-life of cefuroxime was 1.6 +/- 0.3 hours compared with a terminal half-life of 21.7 +/- 5 hours after treatment. The total cefuroxime clearance was 120 +/- 22 ml/min. The hemofiltration clearance represented 86% of the total clearance and the hemofiltration process removed in average 63% of the dose. During CAVH the terminal half-life of cefuroxime was 7.9 +/- 2.2 hours. The total plasma clearance for cefuroxime was 32 +/- 7.5 ml/min where the CAVH-treatment represented only 34% of the total clearance. From these data we suggest that a full loading dose (1.5 g of cefuroxime) should be given after each intermittent hemofiltration treatment when performed every second day. In CAVH, where nonrenal clearance will influence the dosage scheme significantly, we suggest an initial dose of 1.5 g of cefuroxime to be followed by a supplementary dose of 750 mg every 20-24 h.

Aged↗

Endotoxemia in chronic renal failure.

In the past years dialyzers have been improved, and consequently pyrogenic reactions have become rare. However, some patients in our dialysis unit have shown symptoms during hemodialysis which we suspected could be caused by endotoxins. These patients, as well as controls without similar symptoms, had elevated levels of circulating endotoxin. We therefore measured endotoxin in blood from patients with chronic renal failure and different kinds of treatment. Serum samples were analyzed with a sensitive method described in the literature, using a chromogenic substrate and Limulus amebocyte lysate. In patients on hemodialysis (mean +/- SEM) the endotoxin value in samples taken immediately before dialysis was 40 +/- 4.7 ng/l and significantly elevated (p less than 0.001) compared with the endotoxin value (7 +/- 0.6 ng/l) found in the healthy reference group. Increased endotoxin levels were also seen in patients on hemofiltration (19 +/- 7.5 ng/l) and in patients with conservative treatment and various degrees of renal insufficiency (17 +/- 2.5 ng/l). Patients on peritoneal dialysis and renal-transplanted patients had levels not different from the controls. The mechanism behind endotoxemia in uremia is unknown but may partly be explained by reduced endotoxin elimination due to impaired liver macrophage function. The differences in endotoxin levels in patients on peritoneal or hemodialysis treatment may reflect that extracorporeal circulation enhances endotoxin entrance to the circulation and/or that endotoxin clearance is dependent on the dialysis regimen.

Adolescent↗

Infection-induced urinary calculi and renal failure.

During 1974-1984 altogether 481 patients were treated for end-stage renal disease (ESRD). Eight patients, five women and three men, with chronic pyelonephritis as the primary cause of ESRD, had staghorn urinary calculi as a predisposing factor for renal failure. These eight patients were studied retrospectively concerning epidemiological and bacteriological aspects, the treatment of the stone disease, and the development of uraemia. Anatomical and metabolic abnormalities such as bladder outlet disturbances, primary hyperparathyroidism, phenacetin abuse or metabolic stone disease were found in six patients. The women had all been infected with Proteus mirabilis, whereas the men had been infected with various microorganisms. The average time taken for the development of ESRD, estimated from the first sign of renal impairment, was 7.4 +/- 2.9 (SD) years. Five patients had died before this study commenced. One of the patients still alive was on dialysis treatment. Two patients who were doing well without dialysis were stone free and had sterile urine after successful pyelolithotomy. It is concluded that the prevalence of infectious urinary calculi as a cause of uraemia in patients with ESRD is low. The time taken for uraemia to develop is short in these patients and they often have anatomical abnormalities. Proteus is commonly found in this group of patients. Patients with staghorn calculi, urinary tract infection and impairment of renal function are at risk of developing uraemia.

Aged↗

Ceftazidime as prophylactic treatment in renal stone surgery. Clinical evaluation and pharmacokinetics in renal tissue.

The effect of ceftazidime in surgery of renal stones associated with urinary tract infection was investigated and its pharmacokinetics in serum and renal tissue was compared in 14 patients (15 kidneys) operated on for renal calculi associated with multiple urinary tract infection. Two to four days preoperatively ureteric catheterization was performed to localize the level of the infection and 2 g of ceftazidime was given intravenously twice daily for 10 days. Renal biopsy, serum samples and in one patient renal lymphatic fluid were taken simultaneously for antibiotic assay. Urine cultures were performed at regular intervals pre- and postoperatively. Ten patients had bacterial growth in the stone-carrying renal pelvis. The same strain was found in the bladder as in the pelvis. Nine patients had sterile urine after 3-5 days of treatment. One patient with bilateral stones did not get sterile urine until after seven days of treatment. Bacterial growth was found in two out of six cultured stones obtained from patients with bacterial growth in the pelvis. The decreases in concentration of ceftazidime in serum and renal tissue seemed to be parallel. Slight reversible elevation of liver transaminases was noted in 5/14 patients. It is concluded that the concentration of ceftazidime in serum parallels that in renal tissue. Ceftazidime seems to be an effective prophylactic in renal stone surgery and the preoperative dose should be given close to the operation.

Adult↗

Chronic renal failure in Khartoum, Sudan.

A study of the clinical presentation and conceivable causes of chronic renal failure (CRF) in 61 Sudanese patients in Khartoum is presented. The clinical features involved almost all the systems, however, gastrointestinal and cardiovascular signs and symptoms predominated. The causes of chronic renal failure in Sudan and Sweden are also studied for comparison. The causes of CRF in Sudan are chronic glomerulonephritis, obstructive nephropathy (stone disease), hypertension and diabetes mellitus in that order. The main causes of CRF in Sweden are chronic glomerulonephritis, diabetes mellitus and chronic pyelonephritis. Of the 61 Sudanese patients 16 have kidney transplants, only one in Sudan, three patients are on regular hemodialysis, nine patients are on intermittent peritoneal dialysis, 16 are on conservative treatment and 17 died during the course of treatment.

Adolescent↗

Crystal inhibition: the effects of polyanions on calcium oxalate crystal growth.

The inhibition of calcium oxalate crystal growth by the glycosaminoglycans, chondroitin sulphates and heparin, by the low-molecular-weight heparin analogue pentosan polysulphate and by Tamm-Horsfall glycoprotein extracted from human urine, was measured by using a seeded crystal procedure and compared with the inhibition by pyrophosphate. It was found that the most pronounced inhibition was obtained with the polyanions with the highest charge density, i.e., heparin and pentosan polysulphate. Tamm-Horsfall glycoprotein caused an inhibition of a similar magnitude as urinary chondroitin sulphates. Urinary polyanions with a high affinity to Sepharose 4B were more efficient inhibitors than those with a low or no affinity to the gel. It is concluded that urinary polyanions are important inhibitors of calcium oxalate crystal growth and that the potency of inhibition increases with the charge density.

Anions↗

Binding of glycosaminoglycans to sodium urate and uric acid crystals.

The binding of heparin, chondroitin sulphate and the low molecular weight heparin analogue pentosan polysulphate to sodium urate and uric acid crystals was studied by the use of radioactively labelled glycosaminoglycans were used in the binding step, and varying amounts of unlabelled glycosaminoglycans for the competition experiments. The experiments were carried out in 140 mmol/l NaCl at pH 6, with or without 5 mmol/l CaCl2 in the solution. A reversible and almost complete binding of heparin and chondroitin sulphate to sodium urate crystals did occur in the presence of calcium, whereas pentosan polysulphate bound incompletely. The binding was much less pronounced in the calcium-free conditions. Uric acid crystals did not bind any of the three inhibitors, not even with calcium present. The clinical relevance depends on whether sodium urate microcrystals are present in the urine of calcium stone patients, to cause a binding and thereby a masking or inactivation of these inhibitors in the urine, which seems to be possible in the presence of calcium. However, the potential of pentosan polysulphate for the treatment of calcium stone patients does not seem to be at risk from this effect.

Binding, Competitive↗

Enzymatic determination of urinary chondroitin sulphate: applications in renal stone disease and acromegaly.

A method was developed for the determination of urinary chondroitin sulphate (CS), including dermatan sulphate and chondroitin 4 and 6-sulphates, using an enzymatic degradation with chondroitinase-ABC followed by precipitation with Alcian blue, whereby CS was determined as the difference between undigested and chondroitinase digested material. The method was linear in the range 0-100 mg l-1 with a detection limit of 1 mg l-1 and allowed determinations on small urine volumes without pretreatment of the urine. It could be demonstrated that males excreted more CS than females, and growing children had the highest urinary content of CS. Renal calcium stone formers did not differ from healthy controls in urinary CS. Patients with acromegaly had a higher excretion of CS compared with controls. There was also, in these patients, a positive correlation between the serum growth hormone levels and the urinary CS, indicating that CS-excretion may be an estimate of the activity of the pituitary disorder.

Acromegaly↗