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Biomedical subjects

C Olbricht

Publications and source records attributed to C Olbricht.

9 recordsLinked to original sources
PubMed1997

Accumulation of lovastatin, but not pravastatin, in the blood of cyclosporine-treated kidney graft patients after multiple doses.

OBJECTIVES: To study pravastatin and lovastatin pharmacokinetic and pharmacodynamic effects and their interactions with cydosporine (INN, ciclosporin) in kidney transplant patients after single and multiple doses. SUBJECTS AND METHODS: The pharmacokinetic and pharmacodynamic effects of administration of 20 mg/day oral pravastatin and lovastatin for 28 days and their interactions with cyclosporine (2 to 6 mg/kg/day) were studied in a double-blind, double-dummy, randomized, parallel-group multicenter trial in 44 stable kidney graft recipients. RESULTS: The median area under the curve [AUC(0-24)] of pravastatin was 249 microg x hr/L (range, 104 to 1026 microg x hr/L) after a single dose (day 1) and 241 microg x hr/L (114 to 969 microg x hr/L) after multiple doses (day 28) and was fivefold higher than values reported in the absence of cyclosporine. The median AUC(0-24) of lovastatin was 243 microg x hr/L (105 to 858 microg x hr/L) on day 1 and 459 microg x hr/L (140 to 1508 microg x hr/L) on day 28. Besides a significant accumulation during the study period (p < 0.001), the lovastatin AUC(0-24) values were twentyfold higher than values reported without cyclosporine. Coadministration of pravastatin or lovastatin did not alter cyclosporine pharmacokinetics. In this study, 20 mg/day doses of both drugs resulted in a significant improvement of the lipid profile and were well tolerated. CONCLUSIONS: In contrast to lovastatin, pravastatin did not accumulate over the study period, which is probably one of the reasons rhabdomyolysis has been reported in lovastatin-treated but not pravastatin-treated transplant patients receiving cyclosporine immunosuppression.

Adult↗
PubMed1994

[Accuracy of CT angiography in the diagnosis of renal artery stenosis].

Spiral CT in the form of CT angiography (CTA) provides a new method for the investigation of the large vessels. 52 patients with suspected renovascular hypertension were examined by CTA and arterial DSA. The computer tomographic and angiographic findings in 124 renal arteries were compared. Sensitivity of CTA for demonstrating renal artery stenosis was 95%, and for relevant stenoses it actually reached 100%. Specificity was 92%. Positive/negative prediction value was 85% and 100%. CTA proved outstandingly good for demonstrating or excluding renal artery stenosis and was superior to other imaging methods in several respects. CTA requires high contrast values, optimal timing and careful evaluation. Amongst various forms of image reconstruction, interactive viewing of the primary axial images and multiplanar reconstruction in a cine mode are essential and MIP projections are valuable.

Adult↗
PubMed1991

Barium carbonate intoxication.

A 22-year-old man attempted to commit suicide by swallowing an unknown amount of barium carbonate dissolved in hydrochloric acid. Shortly after ingestion, he developed crampy abdominal pain and generalized muscle weakness. About 2 h later, respiratory failure ensued necessitating orotracheal intubation and mechanical ventilation. Concomitantly, life-threatening arrhythmias including ventricular fibrillation occurred, and he had to be resuscitated for 45 min. After correction of severe hypokalemia (serum potassium 1.5 mmol/l), cardiac rhythm stabilized. In an attempt to accelerate removal of barium from the circulation hemodialysis was begun. During hemodialysis muscle strength returned. Pharmacokinetic analysis of serum barium levels suggest that hemodialysis shortened the serum half-life of barium. Subsequently, the patient made a complete and uneventful recovery. Our case demonstrates that severe barium poisoning can be survived provided that early aggressive therapeutic measures are undertaken. Hemodialysis seems to be efficacious in the therapy of barium intoxication.

Adult↗
PubMed1989

Ciclosporin A inhibits endothelium-dependent vasodilatation and vascular prostacyclin production.

Aortic rings dissected from rats treated with ciclosporin A (30 mg/kg per day for five days) showed reduced relaxation induced by the endothelium-dependent vasodilator acetylcholine, but unchanged responses induced by glyceryl trinitrate. After eight weeks of ciclosporin A treatment, the relaxation induced by both acetylcholine and glyceryl trinitrate was inhibited. In addition, phenylephrine-induced contractions were slightly enhanced and vascular prostacyclin production was reduced by more than 80%. These effects may participate in the hypertensive and thrombo-embolic complications associated with the clinical use of ciclosporin A.

6-Ketoprostaglandin F1 alpha↗
PubMed1978

The early phase of experimental acute renal failure. III. Tubologlomerular feedback.

Experiments were designed to determine whether tubologlomerular feedback, which modifies nephron filtration rate in response to alterations in the macula densa sodium chloride concentration, was still apparent in the initiation phase of various types of acute renal failure. The response of the glomerulus to changes in the macula densa stimulus was evaluated in haeme pigment, ischaemic and nephrotoxic induced renal damage by measuring early proximal flow rates. The sodium chloride concentration at the macula densa was varied between low values and isotonicity in two ways: firstly, by interruption of flow through the loop of Henle, followed by orthograde perfusion with Ringer's solution; secondly, by retrograde perfusion of the loop of Henle with isosmotic mannitol or Ringer's solution. In all nephrons examined, filtration rate was inversely correlated to the macula densa sodium chloride concentration, except during orthograde perfusion with 10(-4) M furosemide in Ringer's solution, when, despite the high sodium chloride concentration, filtration rate remained high. It is concluded that the mechanism of tubuloglomerular feedback is viable after the onset of compromised renal function, and may, as postulated, account for the reduction in blood flow and nephron filtration rate occurring in acute renal failure.

Acute Kidney Injury↗
PubMed1977

The early phase of experimental acute renal failure. I. Intratubular pressure and obstruction.

Tubular obstruction in acute renal failure, postulated to cause the restricted excretory function, is suggested by raising intratubular pressure, to lower effective filtration pressure and diminish urine output. To examine the applicability of the obstruction hypothesis to the pathogenesis of experimental acute renal failure, proximal intratubular pressure and renal function were measured after renal insults of different origins and severity. Obstruction in acute renal failure kidneys should manifest itself as an increase in intratubular pressure for a least 12 h, for within this time period following ureteral occlusion, elevated pressures were found to reflect obstruction. The consistent existence of raised proximal intratubular pressure in acute renal failure kidneys could not be detected; ischaemic and nephrototoxic models were found in which no rise in intratubular pressure could be demonstrated. The oliguric nature of acute renal failure kidneys could not be verified; ischaemic and nephrotoxic models were found in which urine output was either normal or enhanced. Only for methaemoglobin induced renal failure were raised intratubular pressure, oliguria and casts concurrent. It is concluded that obstruction is not a consistent feature of experimental acute renal failure and that the obstruction hypothesis may be specifically applicable to only a few models, which include haeme pigment and folic acid induced renal failure.

Acute Kidney Injury↗
PubMed1977

The early phase of experimental acute renal failure. II. tubular leakage and the reliability of glomerular markers.

Experiments were designed to determine whether leakage of substances across the tubular epithelium, which are impermeant in the normal kidney, falsifies the measurement of glomerular filtration rate in acute renal failure. Permeability to those substances most commonly used for filtration rate determination, polyfructosan, inulin and ferrocyanide, was estimated by measuring their recoveries following perfusion through various nephron segments in haeme pigment, ischaemic and nephrotoxic models of acute renal failure. Late proximal recovery of 14C ferrocyanide was only marginally decreased compared to controls, by a maximum of 6%. Distal recovery of polyfructosan, 14C and 3H inulin were depressed somewhat more, by a maximum of 11%. Urinary recovery of 14C inulin was reduced by only 15% in kidneys showing severely restricted renal function. It is concluded that tubular leakage is not a feature of significance in the early phase of moderate acute renal failure, that ferrocyanide and inulin are reliable markers for the determination of nephron filtration rate and water reabsorption, and that the reduction in whole kidney inulin or polyfructosan clearance reflects primarily a reduction in glomerular filtration rate.

Acute Kidney Injury↗