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Biomedical subjects

U Binswanger

Publications and source records attributed to U Binswanger.

At least 19 recordsLinked to original sources

Nature and rate of vascular refilling during hemodialysis and ultrafiltration.

The change of blood volume, of blood and plasma density (rho b, rho p) following a short ultrafiltration pulse (duration: 20 min; mean rate -35 ml/min) within the first hour of hemodialysis was analyzed in 13 hemodynamically stable patients (30 single measurements). Protein concentration of refilling volume (7 g/liter) was calculated from its density (1009.25 +/- 3.7 kg/m3, at 20 degrees C) and from the linear relationship between plasma density and protein concentration (cp) of uremic plasma samples (rho p = 1007.46 + 0.2422 x cp). The filtration coefficient (Lp,calc) determined from a relation derived from Starling's hypothesis was 5.6 +/- 1.4 ml/(min.mm Hg.50 kg lean body mass); N = 13, mean +/- SD, minimum 3.2, maximum 8.0. A model describing the dynamics of blood and plasma volume was developed. It was fit to on-line measurements of relative blood volume changes by variation of the filtration coefficient and of initial blood volume (Lp,fit, Vb,fit). The linear regression between Vb,fit and blood volume determined from anthropometry (Vb,calc) was highly significant (r = 0.79, N = 30, P < 0.001). Compared to Vb,calc, Vb,fit was typically increased by 21 +/- 11%, reflecting a fluid overload at the beginning of the treatment. Lp,fit was not different from Lp,calc. Lp,fit significantly increased with blood volume excess. Due to the small but definite protein content of refilling volume, the model accounts for increased blood volume recovery and occasional overshoot of blood and plasma volumes following ultrafiltration.

Adult

Stimulation of erythropoietin in renal insufficiency by hypobaric hypoxia.

Patients with renal anaemia show inadequate levels of immunoreactive erythropoietin (Epo) related to the degree of anaemia. The purpose of our study is to compare the degree of stimulation of Epo by means of hypobaric hypoxia in normal controls and patients with renal anaemia. Baseline Epo concentrations were found to be 11.1 +/- 2.0 U/l in 10 healthy volunteers and 11.4 +/- 4.6 U/l in six patients with renal anaemia. After exposure to hypobaric hypoxia equivalent to 4560 m above sea level for a duration of 3.5 h, we observed a significant increase in serum Epo in healthy volunteers to 22.8 +/- 9.1 U/l (P < 0.005), while there was no increase in patients with renal anaemia: 12.3 +/- 5.2 U/l (P < 0.2). Our results show that in patients with renal anaemia serum Epo concentrations are comparable to those of normal controls, but inadequate in view of the concomitant degree of anaemia. Stimulation by acute hypobaric hypoxia was not possible in patients with renal insufficiency as opposed to normal controls. From these data it can be concluded that either Epo production is working at maximum capacity under baseline conditions, or an additional hybobaric stimulus is not able to influence a disturbed set point of the oxygen sensor regulating Epo synthesis.

Adult

[Results of kidney transplantation in patients over 60 years of age].

In the same measure as the age of population is growing, the importance of the problems rising by the renal transplantation in elder persons is increasing. At the University Hospital of Zurich 1313 kidney transplantations were performed between 1964 and 1990, 44 of them to patients who at the moment of operation were older than 60 years of age. The actuarial patient survival after 3 months reached 81%, after 1 year 74% and after 5 years 42%. The actuarial allograft survival after 3 months was 75%, after 1 year 67%, after 5 years 40%. The mortality was 131 per 1000, the mortality ratio compared to a standard population 6 times higher. The main causes of death were infections (52%) and cardiovascular diseases (28%). These results explain our opinion, that renal transplantation in elder patients should be indicated retentively.

Adult

Hyperparathyroidism after kidney transplantation: a retrospective case controlled study.

We studied retrospectively patients with hyperparathyroidism after successful renal allotransplantation. Since 1972, 1119 transplantations have been performed in our department, and 534 patients survive with functioning grafts. Hyperparathyroidism requiring parathyroidectomy developed in 32 (5.9%). The frequency of interventions increased markedly after introduction of cyclosporine A treatment in our unit. The time between transplantation and parathyroidectomy was 22.5 months (SD 16.5, range 1-82 months). The age of the patients was 49.0 years (SD 10.5, range 17-63 years); the group consisted of 16 female and 16 male patients. All patients but two (no measurement performed) repeatedly exhibited high serum parathormone and calcium levels and therefore underwent surgery. In comparison to a control group, matched for time of transplantation, age, sex, and cause of renal failure, the patients with hyperparathyroidism had longer dialysis treatment (54.2 months, range 9-132 vs 26.9 months, range 1-72) and exhibited lower phosphate concentrations in the early posttransplantation period. Before surgery, serum chemistry was different for hyperparathyroid and control subjects: serum calcium 2.80 +/- 0.23 mmol/l vs 2.48 +/- 0.13 mmol/l and alkaline phosphatase 157.4 +/- 92.0 U/l vs 85.2 +/- 51.5, respectively. We did not see any influence of oral phosphate binders, calcium supplementation, or vitamin D treatment on the development of parathyroid gland hyperactivity during dialysis treatment. Serum creatinine concentration did not change after parathyroidectomy. In four patients, long-term calcium supplementation after surgery was necessary.

Adult

[Dialysis quantity and dietary protein during continuous ambulatory peritoneal dialysis].

Calculation of a dialysis index (Teehan; Perit Dial Bull 1985, 3:152-156) and estimations of the protein catabolic rate (PCR) (reflecting protein intake under steady state conditions) were performed in 20 CAPD patients instructed to eat 1.2-1.5 g/kg BW protein per day and treated with 8-101 dialysate exchange per day. Dialysis indices were 1.20 +/- 0.44, greater than 1.0 reflecting adequate treatment. PCR was based on nitrogen loss by dialysis and urine as well as by losses assumed to be constant in stools and through skin; dialysis loss was obtained either by collection of the 24 h dialysate volume or by estimating the equilibration ratio between blood and dialysate for calculation of nitrogen removal from serum urea nitrogen and 24 h dialysate volume. Values obtained were 0.90 +/- 0.23 and 0.89 +/- 0.23 g/kg BW, respectively (r = 0.97, P = 0.0001). These low PCR values were found to correlate with data from dietary surveys (r = 0.77). Total serum protein, albumin content and transferrin concentration were all within the normal range and there was no correlation between these parameters and protein intake. It is concluded that protein intake and dialysis adequacy must be monitored individually. Whereas generally recommended CAPD schedules provide effective treatment, a mean protein intake greater than 0.9 g/kg BW seems to be adequate.

Adult

Acute uric acid nephropathy in two gouty patients with moderate hyperuricemia and high urine acidity.

Acute uric acid nephropathy has been described almost uniformly in patients with massive uric acid overload (malignancies with rapid cell destruction, epileptic seizures). Severe hyperuricosuria and intratubular uric acid precipitation result. Here we present two patients with gout, normal uric acid production, and moderate hyperuricemia, both of whom developed acute uric acid nephropathy. Because of pronounced urine acidity (pH values of 4.6 and 5.0 in morning fasting urines), supersaturation with respect to undissociated uric acid exceeded solubility (0.54 mmol/l), despite basal urate secretions of less than 2.2 mmol/24 hours. Additional predisposing factors, such as uricosuric treatment, heavy beer-drinking, over-consumption of purine-rich foods, and hot environment, were superimposed in both cases.

Acute Kidney Injury

[Spontaneous kidney rupture].

Spontaneous rupture of the kidney may occur as a complication of various congenital or acquired renal lesions. We describe three patients with non-traumatic rupture of the kidney, recently seen in our hospital. The rupture was related to polyarteritis nodosa in one case, and in the other two respectively to urothelial carcinoma and to acquired renal cystic disease in end-stage renal disease with continuous ambulatory peritoneal dialysis. In all patients the hemorrhagic complication led to a previously unsuspected diagnosis. After nephrectomy all patients did well. While spontaneous rupture of the kidney is very rare, it is important to consider this complication in the evaluation of a corresponding clinical picture. The possible causes of renal rupture are discussed.

Aged

[The effect of rejection crises and immunosuppressive therapy on the lymphocyte subpopulations of patients after kidney transplantation].

The lymphocyte subsets in the peripheral blood were examined 3 times a week in 17 patients receiving a cadaveric renal allograft using 2-color flow cytometry and several combinations of monoclonal antibodies. Patients who experienced a rejection crisis (n = 12) had a significantly higher CD4/CD8-ratio (2.72 +/- 1.26 mean +/- SD) than patients with stable graft function (1.76 +/- 1.33, p less than 0.05). 9/12 patients showed 0-3 days prior to the rejection episode an increase of the CD4/CD8- ratio (greater than or equal to 0.5) and/or a high ratio (greater than or equal to 2.5) with a decrease following antirejection therapy. The activation markers HLA-DR and IL-2 receptor on T cells were increased only during 3/12 rejection episodes. Patients with rejections resistant to prednisone pulse therapy (n = 6) had significantly more lymphocytes/mm3 in the peripheral blood (1111.7 +/- 597.5) than successfully treated patients (n = 6, 336.7 +/- 196.0, p less than 0.02). Antirejection therapy with prednisone pulses and/or antithymocyte globuline resulted in a significant decrease of T lymphocytes (CD3+) with a selective reduction of T helper/inducer cells (CD4+). 6 months after renal transplantation the patients had a higher percentage of suppressor/cytotoxic cells (CD8+) compared to the pretransplant values (26.3 +/- 10.9% vs 17.7 +/- 6.2%, p less than 0.02) and blood donors (16.3 +/- 6.2%, p less than 0.01). Furthermore the percentage of T helper cells (CD4+/CD28-) was significantly higher and the T suppressor-inducer cells (CD4+/CD28+) were significantly lower compared to the controls. Serial flow cytometric determinations of lymphocyte subsets in renal allograft recipients may be helpful in some cases although rejection episodes could not be predicted in the individual patient.

Adult

Post-transplant diabetes mellitus in renal allograft recipients: a matched-pair control study.

The incidence of post-transplant diabetes mellitus was evaluated retrospectively in 901 consecutive renal transplant recipients. Thirty-two (3.6%) patients developed diabetes mellitus requiring drug therapy. 18 of 32 became hyperglycaemic within 3 months of transplantation. Post-transplant diabetes mellitus occurred in 24 of 628 (3.8%) patients treated with conventional therapy consisting in azathioprine and prednisone, and in 8 of 273 (2.9%) patients receiving cyclosporin A (CsA) in addition (triple therapy). To identify predisposing factors 32 non-diabetic patients matched for age, sex, number of graft, immunosuppressive protocol, and graft function at onset of diabetes were used as case controls. Thirteen of 32 patients with diabetes mellitus and 5 of 32 control patients had abnormal glucose tolerance pretransplant (P less than 0.025). HLA-B8 was significantly more frequent in patients with post-transplant diabetes mellitus than in control patients (9 of 29 vs 2 of 31, P less than 0.02). Twelve (38%) patients became diabetic during or immediately after anti-rejection therapy with intravenous pulse prednisone. Four diabetic patients experienced chronic pancreatitis pre-transplant. Family history of diabetes mellitus, bodyweight, number of rejection episodes, and immunosuppressive drug doses were similar in both groups. Actuarial patient and graft survival was not significantly different in diabetic patients and controls, although 10-year data tended to be better in controls. Thus, post-transplant diabetes mellitus was not a frequent complication in patients sometimes predisposed by an impaired glucose tolerance pre-transplant and was triggered by pulse prednisone therapy in 38%.

Adult

Intravenous 1,25(OH)2 vitamin D3 therapy in haemodialysis patients: evaluation of direct and calcium-mediated short-term effects on serum parathyroid hormone concentration.

Eleven patients on chronic haemodialysis treatment thrice weekly received 1 microgram 1,25(OH)2D3 i.v. after each dialysis for 3 weeks. Phosphate binders were mainly CaCO3, supplemented in a few patients by moderate amounts of Al(OH)3. Ionised calcium was measured by ion-selective electrode, normal values being 1.28-1.42 mmol/l. PTH was estimated by an N-terminal-sensitive assay; normal values are less than 0.25 ng/ml. Results before and after 1,25(OH)2D3 were: ionised calcium before haemodialysis, 1.19 +/- 0.12 and 1.17 +/- 0.14; ionised calcium after haemodialysis, 1.33 +/- 0.07 and 1.30 +/- 0.09; PTH before haemodialysis, 1.39 +/- 0.71 and 1.38 +/- 0.69; PTH after haemodialysis, 0.64 +/- 0.22 and 0.60 +/- 0.17; Phosphate before haemodialysis, 1.85 +/- 0.48 and 2.18 +/- 0.43 (P less than 0.05). No change of PTH concentration and ionised calcium before and after haemodialysis treatment could be documented after i.v. 1,25(OH)2D3 treatment. Mild and severe hyperparathyroidism were indistinguishable. Increased serum calcium concentrations therefore appear to be required for the suppression of PTH secretion by i.v. 1,25(OH)2D3 therapy.

Adult

Continuous pulse-oxymetry during haemodialysis.

Continuous, non-invasive measurement of arterial oxygen saturation (SaO2) during haemodialysis was performed in 18 patients with chronic renal failure. They were dialyzed three times for 2 1/2-3 1/2 h weekly using a capillary polysulfone (F60) or a cuprophane (D2) filter. The total number of O2 saturation curves analyzed was 48. The whole group showed a significant mean decline in SaO2 by 1.9% as compared with predialysis values. In 7 patients with three or more recordings, the significant mean decline in SaO2 was 1.5-4.2% and occurred within 15-60 min after onset of haemodialysis. Evaluation of SaO2 during episodes of severe depression of blood pressure was not possible due to loss of the signal as a consequence of peripheral vasoconstriction. Changes in SaO2 which occurred without any clinical signs or symptoms included very short episodes of depression of SaO2 by 3-22%; a decrease in SaO2 by 3-6% occurring towards the end of the treatment and followed by depressed values for a period of 20-60 min; episodes of marked instability of SaO2 values with differences of up to 10%, lasting 20-60 min and occurring towards the end of the treatment. Application of cuprophane instead of polysulfone filter membranes, first use and reuse of dialyzers, and microemboli blood filters were not found to influence the changes in SaO2. There was a significant difference in the initial decrease in SaO2 during acetate as compared with bicarbonate dialysis.

Blood Gas Analysis

[Treatment of renal osteopathy].

Renal osteodystrophy is defined in the light of bone histology and the clinical and roentgenologic signs are described. Knowledge of the pathogenetic relationships, though incomplete, serves as the basis for the therapy program outlined.

Calcitriol

[Urinary tract infection following kidney allotransplantation: differentiation between bacterial colonization and bacterial infection].

Among 124 recipients of a renal allotransplant (22 men, 52 women), 60 patients (27 men, 33 women) showed more than 10(6) colony-forming units/ml midstream urine on one or several occasions. 26 patients (10 men, 16 women) did not present with leucocyturia whereas 23 (10 men, 13 women) did so. Urine samples were examined 1/2 to 5 1/2 years after transplantation. The comparison of the 2 groups of patients with and without leucocyturia revealed the following: there was no age difference; during the first year after grafting, bacteriuria with leucocyturia was more common; recurrent and de novo infections, dysuria, pyelonephritis and demonstration of E. coli were more frequent. Therapy was more effective in cases of bacteriuria without leucocyturia; the serum creatinine was more seldom elevated above the normal range and complications with ureters, bladder emptying or stenoses of the urethra were more seldomly observed.

Adult

[Replacement of aluminum-containing phosphate binders by calcium and magnesium carbonates in long-term hemodialysis].

Aluminium-containing phosphate binders were replaced by a calcium and magnesium carbonate-containing antacid in 20 patients on long-term haemodialysis, over a three-month period in all of them, for 12 months in ten. After two months the serum aluminium level fell (mean +/- SD) from 3.0 +/- 1.6 to 1.4 +/- 0.5 mumol/l (P less than 0.001). After three months the serum phosphate level had fallen from 1.8 +/- 0.4 to 1.5 +/- 0.4 mumol/l (P less than 0.05), while during the same period parathormone (PTH-NH2) fell from 1.4 +/- 1.4 to 0.8 +/- 0.7 ng/ml (P less than 0.05). Serum total calcium concentration rose after two months from 2.2 +/- 0.2 to 2.4 +/- 0.2 mmol/l (P less than 0.001). In a third of patients the uraemic acidosis was corrected, standard bicarbonate rising from 18 +/- 2 to 21 +/- 3 mmol/l (P less than 0.05). Serum pH, potassium, sodium, magnesium and alkaline phosphatase did not change significantly. Hypercalcaemia was an expected disadvantage: repeated symptom-free episodes of hypercalcaemia occurred in six of 20 patients during the first three months and in a further two up to 12 months. These episodes were successfully controlled by a reduction of CaCO3/MgCO3 dosage and readministration of Al(OH)3. Extraosseous calcifications were not observed.

Adolescent

Successful pregnancy in advanced renal failure without dialysis.

We describe a successful pregnancy in a 22-year-old patient with advanced renal failure, who gave birth to a living boy in the 35th week of pregnancy. At the time of spontaneous delivery the mother had a serum creatinine of 851 mumol/l. No dialysis treatment had been instituted during this successful pregnancy.

Adult

Unidirectional duodenal and jejunal calcium and phosphorus transport in the rat: effects of dietary phosphorus depletion, ethane-1-hydroxy-1,1-diphosphonate and 1,25 dihydroxycholecalciferol.

Unidirectional calcium (Ca) and phosphorus (Pi) transport was studied in vitro by means of a modified Using technique in the absence of electrochemical gradients between the mucosal and serosal buffer medium. Duodenum and jejunum of male albino Sprague-Dawley rats were investigated after Pi depletion alone (0.03% diet-Pi), Pi depletion and EHDP treatment (40 mg/kg per day s.c. X 4), and Pi depletion, EHDP and 1,25(OH)2D3 (500 pmol i.v. X 2) treatment. Mucosal-to-serosal Ca and Pi fluxes (Jms) changed in parallel, depending on the 1,25(OH)2D3-status of the animals. Regarding serosal-to-mucosal fluxes (Jsm), Pi depletion resulted in an increase in Jsm for Ca and Pi, associated with a rise in Gt and Isc in the duodenum but not in the jejunum. EHDP administered to block synthesis of 1,25(OH)2D3 caused further augmentation in duodenal Jsm for calcium but not phosphorus, which was paralleled by an increase in Gt and Isc. After repletion with 1,25(OH)2D3, an increase in Jsm for Ca and Pi and a rise in Gt and Isc were observed in the duodenum and in the jejunum. Serosal-to-mucosal fluxes for Ca and Pi were related to tissue conductance (Gt) in the duodenum (r = 0.89, P less than 0.001 and r = 0.84; P less than 0.001, respectively), as well as in the jejunum (r = 0.55; P less than 0.01 and r = 0.66; P less than 0.001, respectively). Changes in Jsm also paralleled changes in transmural shortcircuit current (Isc). The data are compatible with the assumption of an increase in Jsm for Ca and Pi and a rise in Gt, both reflecting an increase in water recycling across the tight junctions caused by a rise in sodium absorption. They provide further evidence that the overall effect of 1,25(OH)2D3 on intestinal Ca and Pi transport is to increase both cell-mediated active mucosal-to-serosal transport and paracellular diffusional serosal-to-mucosal ion movement.

Animals