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Biomedical subjects

J Brodehl

Publications and source records attributed to J Brodehl.

At least 37 records · Page 2Linked to original sources

Improved absorption of cyclosporin A from a new microemulsion formulation: implications for dosage and monitoring.

Recently, a new oral microemulsion formulation of cyclosporin A (CsA)--Neoral (Sandoz, Basle, Switzerland)--with a higher bioavailability has become available. Ten stable paediatric renal transplant recipients with excessive variations in CsA trough levels with the original Sandimmun (Sandoz, Basle, Switzerland) preparation were switched to Neoral on a 1:1 basis. Pharmacokinetic studies revealed impaired absorption of Sandimmun in six patients. Compared with equal doses of Sandimmun, the 8-h area under the concentration-time curve increased from 1,422 to 2,657 ng x h/ml and the peak concentration rose from 319 to 824 ng/ml (P < 0.01). In six patients with Sandimmun malabsorption, conversion on a 1:1 basis led to a reduction in creatinine clearance which was reversible after dose reduction by 9%-25%. With trough levels at the lower end of the present target range, creatinine clearance stabilised around pre-conversion values.

Adolescent↗

Steroid resistant nephrotic syndrome associated with spondyloepiphyseal dysplasia, transient ischemic attacks and lymphopenia.

Focal segmental glomerulosclerosis, nephrotic syndrome and chronic renal failure were associated with spondyloepiphyseal dysplasia, growth failure, lymphopenia and transient ischemic attacks leading to severe neurological symptoms in three children. Two boys and one girl developed the full syndrome at the age of 5, 6 and 10 years. Positron emission tomography revealed perfusion defects of both cerebral and cerebellar arteries. A variant of the disease was found in two other children who had a nephrotic syndrome and terminal renal failure with only mild spondyloepiphyseal dysplasia, impaired growth and a normal cerebral function. It is concluded that there may be a close association between focal segmental glomerulosclerosis and spondyloepiphyseal dysplasias.

Brain↗

Nifedipine aggravates cyclosporine A-induced gingival hyperplasia.

Gingival hyperplasia is a common side-effect of immunosuppression with cyclosporine A. Nifedipine is often used to control hypertension in kidney graft recipients. Analysis of gingival status in 106 children transplanted at our centre, and treated either with azathioprine, cyclosporine A or both, revealed significantly higher degrees of gingival overgrowth in those children receiving a combination of cyclosporine A and nifedipine compared with those children treated with cyclosporine A or nifedipine alone. Seven children undergoing gingivectomy at our centre over the past few years had received this combination. After a change in the antihypertensive regimen, avoiding long-term nifedipine medication, and improved dental care with chlorhexidine gel, we noted a reduction in the degree of gingival hyperplasia. In the majority of patients, nifedipine could be replaced by a single drug, usually hydralazine. We therefore recommend avoiding calcium channel blockers in the long-term management of hypertension in patients receiving cyclosporine.

Adolescent↗

Absence of cytochrome c oxidase activity in a boy with dysfunction of renal tubules, brain and muscle.

We report on a boy who developed proximal renal tubular acidosis with loss of carnitine at the age of about 6 months. A few months later he began to suffer from progressive muscular weakness and neurological disturbances. Blood biochemistry showed elevated lactate and beta-hydroxybutyrate with increased lactate/pyruvate and beta-hydroxybutyrate/acetoacetate ratios. A high urinary excretion of lactate and citric acid cycle intermediates was found. These results indicated a defect of the mitochondrial respiratory chain. Analysis of biopsy material from skeletal muscle revealed low activities of all respiratory chain complexes. In muscle and fibroblasts cytochrome c-oxidase (complex IV) was absent. Despite high dose multi-vitamin therapy the boy died at the age of 30 months from central respiratory failure. At autopsy the neuropathological diagnosis of Leigh disease was made.

Acidosis, Renal Tubular↗

Regulation of the mitochondrial ATP-synthase in human fibroblasts.

The F1F0-ATPase activity of mitochondrial complex V can be rapidly measured in sonicated preparations of monolayer skin fibroblast cultures from children. We show that direct regulation at the level of ATP-synthase occurs in these cell preparations. ATP-synthase capacity is decreased in response to blocking of the respiratory chain by cyanide (mimicking anoxia) or uncoupling of mitochondria. ATP-synthase capacity falls to 60% and 35% of control, respectively. Up-regulation of ATP-synthase can be demonstrated in fibroblasts exposed to 4 mmol/l calcium (127% of control). Mitochondrial recovery was unchanged under the different incubation conditions as judged by the activity of mitochondrial marker enzymes. We conclude that direct regulation at the level of ATP-synthase occurs in vivo in human fibroblasts. The naturally occurring inhibitor protein IF1 and the calcium binding inhibitor protein CaBI may be involved in this regulation of ATP-synthase.

Adolescent↗

Exercise capacity and blood pressure response in children and adolescents after renal transplantation.

Physical working capacity and cardiovascular response to graded exercise on a bicycle ergometer were investigated in 70 children and adolescents (33F, 37M) after renal transplantation. Results of static and dynamic lung function tests were within the normal range in all patients. Systolic blood pressure, heart rate, pulmonary ventilation and oxygen uptake increased with workload and returned to pre-exercise levels after 5 m of rest. During exercise, blood pressure values were within the normal range in almost all patients. The increase in heart rate and respiratory frequency was blunted in patients receiving beta blocking agents. Maximum workloads (Wmax) were 2.00 +/- 0.48 W/kg in females and 2.38 +/- 0.54 W/kg in males, which are 78 +/- 18% and 84 +/- 18% of the normal values predicted for age. Maximum oxygen consumption (VO2max) was 23.2 +/- 5.8 ml/min/kg in females and 28.3 +/- 5.8 ml/min/kg in males. Half of the patients had height below the third percentile. For this reason exercise capacity in relation to height is probably a more relevant parameter than age. Using actual height, Wmax was 102 +/- 20% and 102 +/- 29%, and VO2max 74 +/- 14% and 80 +/- 18% of predicted values, respectively. We conclude that the adaption of the cardiovascular and respiratory system to graded exercise was influenced by beta blocking agents. Wmax and VO2max were significantly reduced for age in pediatric patients after renal transplantation. Wmax was normal, but VO2max was still reduced if corrected for height.

Adolescent↗

Determination of oxalate excretion in spot urines of healthy children by ion chromatography.

Evidence for the suitability of spot urines for selective screening in children was obtained by comparing the 24-hour urinary oxalate excretion with the ratio of urinary oxalate to creatinine [mmol/mol] in spontaneously voided urine samples. Spot urines of 169 healthy children aged 1 day to 13 years were analysed in order to establish reference values for the urinary oxalate/creatinine ratio in relation to age and body surface area. Oxalate was measured by automated ion chromatography. Results showed an inverse relationship between the oxalate/creatinine ratio and age. The highest ratios, 131 +/- 57 mmol/mol (mean +/- 2 SD), were found in infants. At age two years, the ratio was 84 +/- 55, at age five years 56 +/- 35, and for children older than ten years 42 +/- 31. This finding can be explained by the gain of muscle mass and hence increased creatinine production with increasing age. Data for the urinary oxalate/creatinine ratio are presented according to body surface area for the assessment of children with abnormal growth. In 19 urine samples from nine patients with primary hyperoxaluria, the oxalate/creatinine ratio greatly exceeded (286-2022 mmol/mol) the above reference ranges. We therefore propose the determination of the oxalate/creatinine ratio in spot urines for the selective screening for hyperoxaluria in children with nephrocalcinosis or urolithiasis.

Adolescent↗

Pre-emptive renal transplantation in children and adolescents.

Forty-three out of 204 children received their first renal transplant without prior dialysis. In order to evaluate the outcome of pre-emptive transplantation, two groups were compared retrospectively. The groups consisted of 28 children who received their transplants either without prior dialysis (ND) or after a varying period of dialysis (D). They were matched by age, year of transplantation, immunosuppressive regimen, donor source, and original disease. The percentage of living related donors was 50% in each group. Patient survival was identical in both groups; one patient died in each group due to infection in the early post-transplantation period. The 5-year graft survival rates were 89% in the ND group versus 72% in the D group. The functional parameters graft function, anemia, hyperparathyroidism, hypertension, and the growth rates tended to be slightly better in the ND group than in the D group. The differences, however, were not significant. We conclude that pre-emptive transplantation is a safe procedure that shortens the period of uremia and is, therefore, recommended for children with end-stage renal failure.

Adolescent↗