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Biomedical subjects

U Backman

Publications and source records attributed to U Backman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Values of intact serum parathyroid hormone in different stages of renal insufficiency.

Intact serum parathyroid hormone (PTH) values were determined in 136 patients consulting the out-patient clinic for renal medicine and in 36 patients on maintenance hemodialysis in order to reveal the extent of parathyroid involvement in different stages of renal insufficiency. Elevated PTH values were found in 53 of the conservatively treated patients and in all but 4 of those on hemodialysis. Serum creatinine values and the duration of uremia correlated significantly to serum PTH, and multivariate analyses revealed that these variables were of dominating importance in determining the extent of PTH elevation. The negative relationship between PTH and plasma ionized calcium indicated maintained calcium regulation of hormone release from the parathyroid, although a relative secretory autonomy seemed to develop in parallel with the functional renal impairment. It is concluded that measurements of intact serum PTH values can demonstrate parathyroid hypersecretion in early renal insufficiency and constitutes a useful tool in the management of patients with renal disease.

Adolescent↗
PubMed1990

The excretion of carbonic anhydrase isozymes CA I and CA II in the urine of apparently healthy subjects and in patients with kidney disease.

Carbonic anhydrase isozymes CA I and CA II were assayed by a radio-immunosorbent technique in the plasma and urine of apparently healthy subjects and of patients with renal disease. The concentrations (mean +/- SD, n = 8) of CA I and CA II in the plasma of healthy subjects were 2.3 +/- 2.3 and 0.8 +/- 0.5 mg/l, respectively. The urinary excretion values were 3.8 +/- 2.0 and 3.5 +/- 1.9 micrograms/24 h, and the apparent renal clearances were 21 +/- 17 and 52 +/- 44 microliters/min, respectively, values that are similar to those of other low molecular weight proteins. CA I and CA II have mol. wt of 28,850 and 29,300, respectively, they are globular in shape and have a Stoke-Einstein radius of 25 A. They could, therefore, be expected to be filtered at the glomeruli and thereafter reabsorbed by the proximal tubules. CA II is also present in the cytoplasm of renal proximal and distal tubular cells. A study of the pattern of urinary excretion of CA I and CA II could permit detection of damage to renal tubular cells in two ways--either from defective reabsorption of filtered CA I and CA II by the proximal tubular cells, or from leakage of CA II from the proximal or distal tubules into the urine. Some patients with hypercalcuria and renal tubular acidosis showed increased excretion of these enzyme proteins and of beta 2-microglobulin (BMG) into the urine, but the prevalence was rather low (27%). Further studies of patients with more severely damaged kidneys are required.

Acidosis, Renal Tubular↗
PubMed1990

Influence of the age of cadaveric kidney donors on transplantation outcome and rate of surgical complications.

Cadaveric kidney graft recipients, treated according to a strict, high dose CyA protocol, were followed prospectively for one year. The aim was to study the impact of donor age on transplantation outcome in a homogenously immunosuppressed patient material. The patients were divided into 2 groups; G1: donor age less than or equal to 50 years (mean 34.5 y; range 10-50; n = 49) and G2; donor age greater than 50 years (mean 58.1 y; range 51-68; n = 37). The groups were comparable in terms of recipient age, warm and cold ischemia time, number of HLA A, B, DR mismatches and number of rejection episodes. The result showed no difference in mortality between the 2 groups (12% vs. 13%). One year graft survival was 70% vs. 51% (NS), immediate onset of function was 76% vs. 46% (p less than 0.01), creatinine concentration at one year was 146 +/- 39 vs. 206 +/- 73 mumol/l (p less than 0.05) for G1 and G2, respectively. The most striking finding was a highly significant difference in the rate of graft-related surgical complications, 12% vs. 35% (p less than 0.01) for G1 and G2, respectively. We conclude, that a patient receiving a graft from an elderly donor, runs a higher risk of graft-related complications and that long term graft survival and function also might be influenced by the age of the donor. A possible reason for the inferior results in group 2 might be an increased sensitivity for the toxic effects of CyA of aging kidneys.

Adult↗
PubMed1990

Magnetic resonance imaging of the transplanted kidney. Correlation to function and histopathology.

Interstitial fibrosis is a frequent finding in biopsies from long-term renal allografts, and may be due to chronic cyclosporine nephrotoxicity or chronic rejection. In this study, long-term renal transplants were investigated with magnetic resonance (MR) imaging, and the results were correlated to histopathology and graft function. Seventeen patients were investigated with MR one to 10 years after transplantation and with simultaneous ultrasonographically guided cortical needle biopsy and function tests. Histopathology included semiquantitative grading of degree of fibrosis and quantitation of ratios of tubular structures to interstitial tissue. The correlation between the histopathological assessment of interstitial fibrosis and graft function was good. Poor differentiation between the renal cortex and the renal medulla at MR imaging was correlated to high degree of interstitial fibrosis in the kidney transplants as well as to reduced graft function. MR examination may thus be of value in the evaluation of long-term renal transplants with chronic functional changes.

Adult↗
PubMed1986

Renal allograft rejection: US evaluation.

Real-time ultrasonography (US) was performed on the allografts of 100 consecutive renal transplant recipients at the time of allograft biopsy. Evaluation of the sonograms included the grading of parameters previously demonstrated to be indicative of allograft rejection. The appearance of the renal sinus fat, allograft size, corticomedullary ratio, sharpness of the corticomedullary junction, medullary conspicuity, presence of focal parenchymal abnormalities, and thickening of the pelvic or infundibular wall were individually evaluated. The authors correlated the US and the histopathologic findings. While the accuracy of a positive prediction of rejection was relatively high (83%-90%), this result is influenced by the relatively high prevalence of rejection in the biopsy group (83%). Accuracy of a negative prediction was uniformly low (17%-30%). Mild rejection was difficult to differentiate ultrasonographically from no rejection, although severe rejection could usually be differentiated from mild or no rejection, particularly in patients with the interstitial type of rejection.

Graft Rejection↗
PubMed1985

Allopurinol treatment of renal calcium stone disease.

Thirty-one calcium stone patients were treated with 300 mg allopurinol daily during a mean follow-up period of 2 years. They were also given advice on diet and fluid intake. The effects on the recurrence rate of stones were compared with the effects on the recurrence rate in 43 calcium stone patients who were given similar advice on diet and fluid intake but were not treated with allopurinol. In both groups there was a reduction in the recurrence rate but no difference between patients treated with allopurinol and the control group. Some patients with only hyperuricosuria prior to treatment seemed to benefit from allopurinol treatment, whereas those with hypercalciuria continued to form stones with the same frequency. Allopurinol treatment in calcium stone disease appears less effective than treatment with thiazides, magnesium hydroxide or orthophosphate.

Adolescent↗
PubMed1985

Tubular proteinuria in renal calcium stone formers.

The incidence of tubular proteinuria measured as urinary excretion of beta 2-microglobulin was evaluated in 68 consecutive renal calcium stone formers, 14 of whom had impaired urinary acidification capacity. During normal conditions 13% of these stone formers had tubular proteinuria. There was no statistical difference in the incidence of tubular proteinuria between subgroups with proximal or distal acidification defects. During transient metabolic acidosis induced by an ammonium chloride load a pronounced increase in beta 2-microglobulin excretion was noticed in all patient groups but especially in those with urinary acidification defects. In stone formers with normal acidification capacity the degree of acidosis-induced beta 2-microglobulinuria was moderate but a small group of patients exhibited a large urine excretion of beta 2-microglobulin. This finding may reflect a latent tubular defect of importance for stone genesis.

Acidosis↗
PubMed1985

Renal transplantation in Uppsala.

The history and progress of organ transplantation in Uppsala are reviewed. Renal transplantation was begun in 1969, and the programme now comprises 50 to 60 transplants per year. Since 1976 the operation is performed at the department of urology. Close collaboration has been established with other departments in the hospital, especially with the medical nephrology unit. The indications for active management of uraemic patients have broadened, and maintaining resources on a par with the demands has constantly been a problem. This report concerns immunosuppressive therapy, transplantation results and research connected with the transplantation programme and deals briefly with the prospects for Uppsala as a transplantation centre in the future.

Azathioprine↗
PubMed1985

Fine-needle biopsies of renal transplants in clinical rejection monitoring.

Fine-needle aspiration biopsy( FNAB) of renal allograft transplants has been used at Uppsala University Hospital for 3 years. Experience from 51 consecutive patients (from 1 1/2 years) with 333 FNAB was reviewed. Representative material was obtained in more than 70% of the biopsies. Eleven rejection episodes in 12 patients were confirmed with this method. One was not recognized. Significant inflammation in the kidney without clinical rejection was found in 22 patients. The possible causes of such inflammation are discussed. Repeatedly recorded inflammation in the kidney with minor or no effect on graft function may sometimes be caused by viral infection. The clinical value of FNAB in various immunosuppressive regimens is discussed.

Azathioprine↗
PubMed1983

Ambulatory diagnostic evaluation of 389 recurrent renal stone formers. A proposal for clinical classification and investigation.

389 consecutive renal stone formers (275 males, 114 females) were investigated in an out-patient stone clinic. Renal tubular acidosis (RTA) was found in 83 patients (22%). Proximal RTA was twice as common as the distal tubular type. The acidification defects were exclusively of the incomplete form with normal basal blood acidbase status. Main diagnoses besides RTA were primary hyperparathyroidism (3.5%), medullary sponge kidney (3.5%), infection induced stones (3%), urate stones (2%), intestinal disorder (1.5%) and cystinuria (0.5%). The metabolic evaluation was mainly based on 24 h urine sampling on a free diet. In 248 patients (64%) no distinct abnormality was considered to be primarily responsible for stone formation. Clinical and biochemical analysis of these so-called idiopathic stone formers disclosed a male preponderance (80%) and, compared to a non-stone-forming control group, a higher urinary calcium excretion, yet with a considerable overlap between the two groups. Hyperuricosuria and hyperoxaluria were rare findings. The conclusion of the study is given as a proposal for clinical classification and ambulatory investigation of renal stone formers.

Adolescent↗
PubMed1983

Uricemia and urinary acidification in renal calcium stone disease.

Serum urate concentrations were determined in 487 consecutive patients with stone disease and in 89 controls. Male controls had higher concentrations than female controls but men and women with stones had lower concentrations than controls. Renal acidification defects, incomplete and complete forms, were found in 25 per cent of the patients with stones, with the highest frequency in patients with hyperuricemia. Patients with proximal renal acidification defects had a higher serum urate concentration than patients with normal acidification of the urine. The urinary excretion of urate was higher in hyperuricemic than in normouricemic patients but lower in patients with hyperuricemia and renal acidification defects than in those with hyperuricemia and normal acidification of the urine. This finding indicates that underexcretion rather than overproduction contributes to the higher serum urate concentration in patients with renal acidification defects. Stone patients with high serum urate levels, especially in combination with renal acidification defects, had more severe stone disease and underwent more operations than other patients with stones. Thus, hyperuricemia does not appear to be a common feature in patients with calcium stone disease, although it is associated with formation of large stones for unknown reasons.

Adult↗
PubMed1982

Urinary excretion of urate in renal calcium stone disease and in renal tubular acidification disturbances.

The 24-hour urinary excretion of urate was investigated in 467 consecutive stone formers - 350 males and 117 females - and 89 apparently healthy controls with no history of stone disease. Males had a higher urinary excretion of urate than females but there was no difference between stone formers and controls. Urinary urate decreased with advancing age. Patients with a proximal tubular acidification defect had a lower urate clearance than patients with a normal acidification of the urine. Patients with hyperuricosuria presented a higher frequency of stone operations but a lower stone episode rate than matched normouricosuric stone formers. Hyperuricosuria in combination with renal acidification defects was associated with the highest frequency of stone operations. Hyperuricosuric patients also had a higher excretion of calcium than normouricosuric patients. Hyperuricosuria is not a common feature of calcium stone disease but when present is associated with a more severe stone disease in terms of stone operations.

Acidosis, Renal Tubular↗