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Biomedical subjects

B Kutkuhn

Publications and source records attributed to B Kutkuhn.

36 records · Page 2Linked to original sources
PubMed1991

[Kidney function of patients with healthy kidneys during cyclosporin treatment].

Long-term administration of ciclosporin has been complicated by side-effects, the predominant being nephrotoxicity. We performed renal function studies on 20 patients treated with ciclosporin (group 1) and on 12 patients serving as controls (group 2). Only patients with serum creatinine less than 1.3 mg/dl entered the study. The renal function studies consisted of: Inulin clearance, PAH clearance, sodium sulphate loading, sodium bicarbonate loading. Plasma renin activity (PRA), inactive renin (IR) and aldosterone (ALDO) were measured basally and after stimulation with 40 mg furosemide i.v. Serum creatinine was not significantly impaired under ciclosporin with 1.1 +/- 0.1 mg/dl vs 0.9 +/- 0.1 mg/dl in the control group (ns). Glomerular filtration rates as measured by creatinine and inulin clearance were significantly impaired in group 1 as compared to group 2. Inulin clearance was impaired by ciclosporin with 93.5 +/- 4.4 ml/min/1.73 m2 as compared to 121 +/- 6.6 ml/min/1.73 m2 (p less than 0.05) in patients of group 2. The PAH clearance in ciclosporin treated patients was impaired, with 379 +/- 22.1 ml/min/1.73 m2 in group 1 as compared to 605 +/- 39 ml/min/1.73 m2 (p less than 0.001) in group 2. Mean arterial pressure and renovascular resistance were significantly increased in ciclosporin treated patients. We demonstrated, by means of sodium sulphate and bicarbonate loading, incomplete distal tubular acidosis in 3 patients from group 1 but in none of group 2. There was no difference in basal plasma renin activity (PRA), but during volume contraction induced by furosemide there was only blunted response by PRA in patients receiving ciclosporin with 2.7 +/- 0.3 ng/ml/h as compared to 7.7 +/- 0.5 ng/ml/h in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1991

Renal artery stenosis: preliminary results of treatment with the Strecker stent.

Use of the Strecker flexible balloon-expandable tantalum stent for treatment of renal artery stenosis after failed angioplasty or transaortic thromboendarterectomy was evaluated in 10 patients (nine hypertensive, one normotensive). Left (n = 3) and right (n = 5) renal arteries were involved; renal artery stenosis in two patients had developed after kidney transplantation. Indications for stent placement were inadequate immediate postangioplasty response (n = 7), development of considerable restenosis after angioplasty (n = 1), and obstructing intimal flaps following transaortic endarterectomy (n = 2). Stent placement was technically successful (less than 20% residual stenosis) and patency was preserved in eight patients. Of the seven hypertensive patients with successful implantation, two were cured, three had improvement, and two had no change at latest follow-up evaluation (mean, 10.6 months; range, 6-12 months). The Strecker stent may be helpful in treating restenosis after failed revascularization procedures, although the precise indication, true safety, and long-term efficacy of stent placement in renal arteries will not be known until trials with more subjects and longer follow-up periods are completed.

Adult↗
PubMed1991

Plasmapheresis in solar urticaria.

Three patients with solar urticaria were treated with plasmapheresis. By intradermal injection of in vitro irradiated serum the existence of a circulating photoallergen was demonstrated in cases 1 and 2 but not in case 3. Plasmapheresis induced complete remission of solar urticaria in case 1 and transient improvement in case 2. In case 3, however, no beneficial effect was observed. It is suggested that some patients with solar urticaria, probably those with a circulating photoallergen, may benefit from plasmapheresis.

Adult↗
PubMed1991

Validity of the captopril test for identifying correctable unilateral renovascular hypertension.

In order to validate the captopril test for identification of patients with renovascular hypertension (RVH), we performed the test with 118 patients suspected of suffering from RVH who were receiving antihypertensive medication. On the basis of 44 patients with proven RVH and 74 patients with primary hypertension (PH), the sensitivity, specificity and posterior probability for the captopril test were calculated separately for patients undergoing and not undergoing diuretic therapy. An absolute rise in plasma renin activity (PRA) and a relative rise in PRA served as discriminating indicators. The absolute increase of PRA after captopril administration in the absence of long-term therapy with diuretics yielded the best posterior probability in the one-dimensional model, with a sensitivity of 89% and a specificity of 97%. Linking of the variables "absolute" and "relative rise of PRA" reduced the misclassification rate to 5%. This validation allows an accurate distinction between RVH and PH on the basis of the captopril test even when antihypertensive therapy is not suspended (except for ACE inhibitors and diuretics).

Adult↗
PubMed1991

Influence of betaxolol on renal function and atrial natriuretic peptide in essential hypertension.

The hypotensive action of beta-adrenoreceptor blockers is not fully understood, there being a lack of studies focusing on possible relationships between beta-blockers and the secretion of atrial natriuretic peptide (ANP). In 10 patients with essential hypertension, we investigated the influence of betaxolol, a selective beta 1-adrenergic blocking agent, on renal function and on plasma levels of ANP during exercise, volume depletion and volume expansion. Chronic therapy with betaxolol (mean 14.5 mg/day) did not alter glomerular filtration rate and renal blood flow although blood pressure was reduced. Renal vascular resistance decreased from 12795 +/- 1064 dyn/s per cm5 to 10614 +/- 833 dyn/s per cm5 (P less than 0.005). Under betaxolol, basal ANP levels increased from 39 +/- 10 pg/ml to 80 +/- 19pg/ml (P less than 0.01). ANP increased during exercise and volume expansion but was decreased during volume depletion. ANP values observed under betaxolol treatment showed significantly higher values while preserving their dynamic features. We believe that the stimulating effect of betaxolol on ANP may at least partly account for its hypotensive action.

Adolescent↗
PubMed1990

Sympathetic blockade by epidural anesthesia attenuates the cardiovascular response to severe hypoxemia.

Blood pressure is usually well maintained during epidural or spinal anesthesia even in the presence of extensive sympathetic blockade. The authors investigated whether hormonal systems support arterial pressure and how the circulation copes with a hypoxic challenge when activation of the sympathetic nervous system is selectively impaired by neural blockade. Accordingly, the effects of high epidural anesthesia alone and combined with hypoxia were evaluated in seven awake trained dogs. On different days, either bupivacaine 0.5% (8-12 ml) or saline (placebo) were randomly injected epidurally and the effects evaluated on cardiovascular (arterial pressure, heart rate) and respiratory (blood gases, oxygen consumption) variables, as well as on hormone plasma concentrations (vasopressin, norepinephrine, epinephrine, renin) during both normoxia and hypoxia. During epidural anesthesia alone, vasopressin increased tenfold (1.7 pg/ml +/- 1.0 SD to 16.8 +/- 13.8, P less than 0.05), norepinephrine decreased (90 pg/ml +/- 31 to 61 +/- 28, P less than 0.05) while epinephrine and renin concentrations remained unchanged. Mean arterial and pulse pressure decreased by 13 mmHg and 23 mmHg (P less than 0.05), respectively. In dogs without sympathetic blockade (saline group), hypoxemia (PaO2: 31 +/- 4 mmHg) evoked an increase in mean blood pressure by 37 mmHg +/- 8 and heart rate by 50 beats per min +/- 17. In contrast, in the presence of sympathetic blockade but with a similar degree of hypoxemia, blood pressure failed to increase (+ 1 mmHg +/- 14) and heart rate rose by only 15 beats per min +/- 11. These differences between groups were statistically significant (P less than 0.001). Hypoxemia induced a similar hypocarbia (PaCO2:25 mmHg) in both groups, indicating that the ventilatory response to hypoxemia was preserved after epidural blockade. During hypoxemia vasopressin concentrations increased 35-fold to 64 pg/ml +/- 38 (P less than 0.0001) compared to base line only during epidural anesthesia, but not after epidural saline (2 pg/ml +/- 2), while other hormones showed no significant differences. The authors conclude that high epidural anesthesia in awake unsedated dogs: 1) almost completely abolishes the normal cardiovascular response to hypoxemia while promoting vasopressin secretion; 2) preserves the ventilatory response to hypoxemia; and 3) is associated with increased vasopressin concentrations, most likely to compensate for decreased cardiac filling and/or arterial blood pressure when sympathoadrenal responses are impaired. Thus, the changes in cardiovascular vital signs in response to severe hypoxemia are markedly blunted when spinal sympathetic outflow is selectively eliminated by epidural anesthesia.

Anesthesia, Epidural↗
PubMed1989

[Endocrine and nuclear medicine diagnosis of renovascular hypertension].

To check the reliability of the captopril test and of quantitative radioisotope techniques for the primary diagnosis of renovascular hypertension the data from 41 patients suspected of this disease were retrospectively analysed. In all cases plasma renin activity (PRA) was assayed in peripheral blood and in renal vein blood before and after 25 mg captopril. Double tracer studies with 131I-hippuran and 99mTc-DTPA were also performed, as was renal arteriography. The postoperative blood pressure plots of 23 patients with unilateral renal artery stenosis (who had subsequently been operated upon) were included in the evaluation. Renovascular hypertension was diagnosed in 21 patients and essential hypertension in 20. Twelve of the 20 patients with essential hypertension had renal artery stenosis, but this had not produced renovascular hypertension. The diagnostic significance of the tests as markers of renovascular hypertension was as follows: captopril test P less than 0.001, glomerular filtration fraction P less than 0.02, hippuran clearance P less than 0.001. The captopril test and the quantitative radioisotope techniques were in agreement in identifying patients with renal artery stenosis and renovascular hypertension. False-positive results due to methodological shortcomings can be avoided by applying both methods in succession.

Adult↗
PubMed1989

Renal transplantation in amyloid nephropathy.

Renal transplantation was performed in 2 patients with end-stage renal disease due to AA-type amyloidosis. One patient with amyloidosis of rheumatoid arthritis (RA) origin died twelve months after renal transplantation in cardiogenic shock. AA-amyloid deposits were demonstrated in the graft even though there were excellent function and no proteinuria. The second patient with amyloid nephropathy due to familial Mediterranean fever (FMF) showed no impairment of graft function 24 months after transplantation. These 2 cases are compared to an additional 31 cases of renal transplantation for amyloid nephropathy described in the literature. Proteinuria was reported in 32.3% and amyloid was detected in the functioning graft in 41.4%. The function was excellent even when small amyloid deposits were present in the graft. Renal transplantation is indicated in cases of amyloid nephropathy of the AA-type, provided life threatening amyloid involvement of other organs is not present.

Adult↗
PubMed1989

Winner of the ESVS Prize 1988. Effects of prostaglandin E1 (PGE1) on experimental renal ischaemia.

A persisting incidence of acute renal failure has been observed after operative treatment of thoracoabdominal aortic aneurysm, ruptured abdominal aortic aneurysm and renal artery occlusive disease in patients with preoperative impairment of renal function. Because preservation of kidney function can play an important role in the outcome of these patients, the effects of prostaglandin E1 (PGE1) to prevent ischaemic renal failure were studied in an experimental model. Twenty dogs were exposed to 3 h warm ischaemia by clamping of the supra- and infrarenal aorta and both renal arteries. In 10 dogs PGE1 was given intravenously (100 ng/kg/min) for 15 min before clamping. Ten dogs treated with normal saline served as controls. Glomerular filtration rate, renal plasma flow, plasma creatinine, blood urea nitrogen, urine volume, free water clearance and renovascular resistance were calculated before and after renal ischaemia for both groups. The dogs were followed-up for 2 weeks and radionuclide studies with Tc-99m-MAG3, I-131-OIH and In-113m-DTPA were performed on the third postoperative day to calculate global and split renal clearance, tracer extraction fraction and mean transport time. After renal ischemia 9 dogs of the control group and 3 dogs of the PGE1-group developed acute renal failure (P less than 0.05 due to Fisher's exact text). PGE1 infusion significantly attenuated the postischaemic fall in glomerular filtration rate and renal concentrating ability as well as the postischaemic increase of plasma creatinine and blood urea nitrogen induced by 3 h warm renal ischaemia (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1989

[Parametric representation of kidney function using 99mTc-mercaptoacetyltriglycine (MAG3)].

99mTc-mercaptoacetyltriglycine (MAG3) has recently been introduced for imaging kidney function. Due to the much lower radiation dose per MBq, the total administered activity can be much higher than in the case of 131I-ortho-iodo-hippurate (OIH). The improved counting statistics make this tracer useful for parametric imaging of the kidneys. To investigate this potential of MAG3, its kinetics was compared with that of the reference tracer OIH in 38 patients. Parameters of extrarenal tracer kinetics such as the distribution volumes, the whole-body elimination times and the clearance rates showed a good correlation; however, the clearance rate of MAG3 was always lower than that of OIH. The intrarenal kinetics was investigated using the transfer function which was calculated by deconvolution analysis of the renographic curves. Parameters of the transfer function such as the amplitude, extraction fraction and mean transport time demonstrated a high correlation between the two tracers. Since MAG3 seems to be suitable for parametric imaging of kidney function, parametric images of perfusion, uptake, extraction and transport times were calculated by deconvolution analysis of the MAG3 pixel-renograms in various renal disorders. The parameters were distributed homogeneously throughout the parenchyma of normal kidneys. In a kidney with a hemodynamically significant renal artery stenosis the perfusion parameter was decreased and the time parameter was prolonged. Further examples of a renal graft acute tubular necrosis, an obstructive uropathy, an obstructive nephropathy and of a horse-shoe kidney demonstrate that the parametric images are useful for quantitative investigation of regional renal function.

Humans↗
PubMed1989

[Conversion of inactive renin to active renin following acute angiotensin converting enzyme inhibition in essential hypertension and renovascular hypertension].

The physiological role of inactive renin, especially the question of whether and how a conversion to active renin takes place in vivo, remains controversial. In order to show the dynamic alterations from inactive to active renin following acute ACE-inhibition, both forms of renin were investigated in both renal veins and the peripheral circulation of 20 patients with essential hypertension and 20 patients with renovascular hypertension before and 1 h after 25 mg of captopril. Active and inactive renin were determined indirectly as plasma renin activity (PRA, unit: ng/ml x h). In vitro activation of inactive renin was achieved with trypsin (1 mg/ml plasma), followed by a further determination of PRA (= total renin). Subtraction of the active renin from the total renin yields the amount of inactive renin. In patients with essential hypertension, the mean values of active renin increase equally in both renal veins (1.4 and 1.3 before, 1.9 and 1.8 after captopril) and the peripheral circulation (0.9 and 1.3) (p less than 0.002), whereas the inactive renin decreases correspondingly. Renal veins: 7.6 and 8.2 before, 7.2 and 7.6 after captopril; peripheral circulation: 7.7 before and 7.0 after captopril (p less than 0.05). In all patients with renovascular hypertension, there is basally a marked lateralization of active renin (6.4 vs 3.5; p less than 0.01) and inactive renin (20.5 and 18.9, p less than 0.03) towards the side of the ischemic kidney. After captopril, the values for total renin and active renin increase (p less than 0.001), and the side difference for active renin becomes still more pronounced (33.0 vs 14.2; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Captopril-stimulated plasma renin activity in the diagnosis of renovascular hypertension].

In 67 patients thought to have renovascular hypertension, plasma renin activity was measured in both renal veins and peripherally (common femoral v.) before and after administration of 25 mg captopril. Other antihypertensive medication, except diuretics and ACE inhibitors, had been discontinued. The renin ratio, renin secretion indices before and after ACE inhibition, as well as the percentage rise in peripheral plasma renin activity, after captopril were calculated from the measured data. The diagnostic and prognostic value of the various calculation models were compared on the basis of blood pressure changes in 29 patients after intervention (28 operations, one percutaneous transluminal angioplasty). Of the various calculations the renin ratio after ACE stimulation--measuring plasma renin activity separately for each side--was of the greatest value in discriminating for renovascular hypertension (sensitivity 89%, specificity 100%). Comparable results in the discrimination for renovascular hypertension were achieved by determining the rise in peripheral plasma renin activity after captopril. This method is, therefore, a simple, noninvasive test for diagnosing renovascular hypertension with great accuracy even while existing medication is being continued.

Adult↗
PubMed1987

Ten years experience with reconstruction of the chronic totally occluded renal artery.

The criteria for selection of patients who may benefit from reconstruction of totally occluded renal arteries are not well defined. Of those patients who underwent renal artery reconstruction for renal artery occlusive disease at our institution 13% (52/397) had a chronic renal artery occlusion at preoperative arteriography. In 38 cases (73%) the contralateral renal artery had a significant (greater than 70%) stenosis, which was reconstructed simultaneously. Renovascular hypertension alone (n = 27;52%) or in combination with impaired renal function (n = 25;48%) was the indication for surgical treatment and transaortic thromboendarterectomy was the preferred method of reconstruction (n = 38;73%). Operative mortality was 5.7% and during follow-up (38 +/- 31 months) 4 patients died from myocardial infarction (n = 2), aortic dissection (n = 1) or cerebral haemorrhage (n = 1). Postoperatively 20 patients (44.5%) had a normal blood pressure; in a further 20 (44.5%) the hypertension was easier to control and medication could be reduced. Five patients (11%) remained hypertensive. Postoperative arteriography showed a normal patent renal artery in 40 cases (89%). Postoperative plasma creatinine levels ranged from 0.8 to 3.4 mg% (1.32 +/- 0.74) which was a significant reduction from preoperative levels. Two patients with severe uraemia improved to an extent where haemodialysis could be discontinued. Radionuclide scan and the measurements of plasma renin activity before and after administration of a converting enzyme inhibitor (Captopril) were the most reliable diagnostic methods for preoperative patient selection and postoperative follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Disease↗