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Biomedical subjects

B Grabensee

Publications and source records attributed to B Grabensee.

At least 109 records · Page 6Linked to original sources
PubMed1994

Increasing sensitivity and specificity of Doppler sonographic detection of renal transplant rejection with serial investigation technique.

Acute rejection episodes are the most common cause leading to loss of renal grafts in the early postoperative phase. Doppler sonography presents a noninvasive tool to detect increased arterial blood flow resistance as a result of rejection. This can be measured by the increase in the resistive index (RI) and the pulsatility index (PI). In a prospective study including 65 consecutive patients we investigated whether the detection of rejection episodes is improved by determining RI or PI serially twice a week instead of performing a single examination in cases of transplant dysfunction. In 330 examinations with a color-coded Doppler device (Philips QAD 1, Philips Medical Systems Hamburg, Germany) flow profiles were obtained by means of pulse-wave Doppler over at least three interlobar arteries of the renal transplant and RI and PI were calculated. In 41 cases primary rejections were better recognized by an increase in PI compared to the preceding value than by the absolute PI value (with a sensitivity of 90%; specificity was 76% and 42% respectively). The RI was less specific (with a sensitivity of 90%; specificity was 47% for the relative RI increase and 30% for the absolute RI value). The continuous PI increase started an average of 3.3 days (95% CI-15.25 to + 1.55) before rejection was diagnosed. Vascular rejection episodes showed higher PI values than interstitial rejections (3.86 +/- 2.14 vs. 2.19 +/- 0.87; P < 0.01). The serial investigation technique of PI allows better recognition of rejection episodes than the single measurement of RI or PI performed so far. Doppler sonography recognizes rejection at an early stage.

Acute Disease↗
PubMed1994

Monitoring of osteoblast activity with an immunoradiometric assay for determination of bone alkaline phosphatase mass concentration in patients receiving renal transplants.

We examined the diagnostic validity of an immunoradiometric assay for determination of mass concentration of bone alkaline phosphatase (EC 3.1.3.1) in 134 sera from 35 patients receiving renal transplants. Comparison between bone alkaline phosphatase concentration and total alkaline phosphatase activity yielded a strong correlation (r = +0.860; P < 0.001). Nine (17%) of 54 sera which were characterized by a total alkaline phosphatase activity between 100 units/l and the upper reference limit (178 units/l (males) and 160 units/l (females), respectively) showed an increased bone alkaline phosphatase concentration (> 21.3 micrograms/l (males) and > 15.0 micrograms/l (females), respectively). There was also a correlation between bone alkaline phosphatase values and parathyroid hormone levels both before (r = +0.640 (n = 23), P < 0.001) and after renal transplantation (r = +0.528 (n = 111), P < 0.0001). A follow-up of 15 patients after renal transplantation revealed that the median of bone alkaline phosphatase values increased from 5.5 micrograms/l before transplantation to 14.9 micrograms/l 3 months after transplantation (P < 0.0001). Nevertheless no correlation could be observed between parathyroid hormone concentrations and bone alkaline phosphatase values at any time following renal transplantation in these 15 patients (P > 0.1). Rise of bone alkaline phosphatase concentration following renal transplantation is most probably due to an activating effect of cyclosporin A upon osteoblasts.

Adult↗
PubMed1994

Results of ultrasound-assisted diagnosis of tunnel infections in continuous ambulatory peritoneal dialysis.

The management of catheter-related infections has become a major challenge in continuous ambulatory peritoneal dialysis treatment. Early recognition and discrimination of mere exit site infections from more invasive and catheter menacing tunnel infections (TIs) are of therapeutic importance. As the diagnosis of TI is still based on clinical signs and only indicates advanced infections, we studied the usefulness of the ultrasound examination (UE) of the continuous ambulatory peritoneal dialysis catheter. Examinations were made by a mobile ultrasound unit using a 7.5 MHz transducer. Sixty-two continuous ambulatory peritoneal dialysis patients with an Oreopoulos Zellermann catheter (Oreopoulos-Zellerman Cathete-THWII, Baxter GmbH, Unterschleissheim, Germany) were studied repeatedly between February 1991 and July 1992. Pericatheter fluid collection (with typical sonographic localization) was consistent with surgical findings and histopathologic examination and proved to be a reliable criterion of TIs. The incidence of TIs was significantly higher when using UE (0.35/patient-year) compared with the usual clinical criteria (0.12/patient-year, P < 0.01). Staphylococcus aureus exit site infections were predominant and had the highest risk of concomitant TIs (83%). Eleven of 25 patients with a positive UE lost their catheter due to infectious complications, while no patient with a negative UE underwent operation for infectious reasons (P < 0.01). The peritonitis rate (0.64/patient-year) was markedly increased when UE indicated a TI (1.7/patient-year, P < 0.01). We conclude that sonography is a sensitive tool for the early diagnosis of unsuspected TIs. Sonography is a bedside method used for screening purposes and allows us to control the treatment regimen.

Adult↗
PubMed1994

Complications following caval interruption.

Caval interruption is widely regarded as the treatment of choice for the prevention of recurrent pulmonary embolism (PE). The safety, ease of insertion and "convenience" of the devices are the main arguments for filter placement. Today many filters are placed for prophylactic reasons, sometimes without an established diagnosis of pulmonary embolism or underlying deep venous thrombosis. Early and late complications have been published but the rate is reported to be low, although only limited numbers of patients have been followed. In an 18-year period 11 patients with problems following caval interruption were treated, 10 with acute complications, one with chronic caval occlusion. Six were treated conservatively, five underwent venous thrombectomy and a.v.-fistula. The device was removed in four. During the same period only three permanent filters were placed in our hospital (two with complications). Caval interruption is useful in selected high-risk patients and is the least invasive but not necessarily the best treatment. Provided stringent criteria are applied, the early and late complications can be accepted in order to prevent sudden death in patients with threatening massive PE. Extended or more liberal indications for caval interruption are neither necessary nor justified.

Adult↗
PubMed1994

Influence of the renin-angiotensin system and atrial natriuretic peptide on renal functional reserve.

We studied the renin-angiotensin system (RAS) and atrial natriuretic peptide (ANP) after amino acid loading in order to elucidate whether or not glomerular hyperfiltration is mediated by these hormones. Eight healthy controls without kidney disease (group 1), 8 renal graft recipients (group 2) and 8 patients after nephrectomy (group 3) were studied. Furthermore, we investigated the influence of amino acid loading on RAS and ANP and glomerular filtration during acute application of captopril in healthy controls. Clearances in insulin (CIn) and para-aminohippuric acid (CPAH) were determined during an infusion of 0.9% saline and during amino acid loading. CIn increased in healthy controls from 96.5 +/- 3.3 to 111.9 +/- 4.4 ml/min (p < 0.01), CPAH rose from 577 +/- 28.7 to 618.9 +/- 38 ml/min (p = NS). During the combined application of amino acid infusion and 25 mg captopril, CIN increased to 125.0 +/- 16.4 ml/min/1.73 m2 (p < 0.01) and there was no significant increase in CPAH which was 595 +/- 77 ml/min/1.73 m2. There was no significant change in renal vascular resistance, but filtration fraction increased from 17 +/- 1 to 19 +/- 1% under amino acid infusion and increased further under the application of captopril to 21 +/- 2% (p < 0.05). In renal graft recipients, CIn had a tendency to increase during amino acid infusion from 78.4 +/- 5.8 to 84.7 +/- 6.5 ml/min (p = NS). In patients after nephrectomy, CIn did not increase (84.5 +/- 6 ml/min) but CPAH did from 345.7 +/- 26.3 to 409 +/- 24.1 ml/min (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Renin secretion and captopril stimulation in hypertensive renal transplant recipients.

Basal renin secretion and the diagnostic value of a captopril stimulation (captopril test) in identifying renovascular hypertension secondary to transplant renal artery stenosis was assessed in 69 patients with hypertension after renal transplantation. An increase of plasma renin activity of 260% 1 h after captopril was considered as a positive result, assuming renovascular hypertension. Six of 69 patients had a positive captopril test, of these patients 5 had transplant renal artery stenosis. These patients were treated with percutaneous transluminal angioplasty (PTA) or surgery. Based on angiographic results and blood pressure response after PTA or surgery the captopril test showed a sensitivity of 100% and a specificity of 92% in the identification of hemodynamically significant stenosis of the transplant artery. Therefore, the captopril test provides a suitable screening instrument for the differential diagnosis of hypertension following renal transplantation.

Adult↗
PubMed1994

Renal functional reserve in patients with IgA glomerulopathy.

UNLABELLED: Seven patients with histologically proven IgA nephropathy and modest impairment of renal function, and 2 patients with IgA nephropathy and nephrotic syndrome were investigated, compared to a control group of 9 healthy individuals, to study the effects of amino acids on glomerular and tubular function, and to evaluate renal functional reserve in IgA nephropathy with different clinical course. Inulin and PAH clearances were used to evaluate glomerular filtration rate (GFR) and effective renal plasma flow (ERPF); proximal and distal tubular fluid delivery and reabsorption were measured by lithium clearance, before and after submission of a standardized amino acid solution. GFR and ERPF increased significantly during amino acid load in healthy individuals and patients without nephrotic syndrome, while filtration fraction (GFR/ERPF) remained constant. Lithium clearance (CLi) and fractional lithium excretion (CLi/GFR) rose significantly in both groups, whereas the reabsorbed volume of fluid in the proximal tubule did not change. In the distal tubule, fractional volume excretion decreased significantly during amino acid load whereas the reabsorbed volume significantly increased. Baseline values of the two groups did not differ significantly. Two patients with nephrotic course of IgA nephropathy showed a distinct decrease in glomerular and tubular function, and a loss of renal functional reserve after amino acid load. CONCLUSIONS: Despite distinct alterations in renal biopsy, IgA nephropathy without nephrotic course presents with a still adequately preserved kidney function and renal functional reserve. A single determination of renal function with noninvasive functional tests does not give valid prognostic information concerning glomerular and tubular function. Therefore, a repeated measurement of renal function at defined intervals might reveal clinical progression of renal disease. The results of the lithium clearance might indicate an increase in tubular function after amino acid load, indicating a tubular adaptation in state of hyperfiltration.

Adult↗
PubMed1994

Colour Doppler ultrasound in the diagnosis of transplant renal artery stenosis.

The validity of colour Doppler ultrasound (CDU) in the detection of transplant renal artery stenosis (TRAS) was investigated. 93 patients presenting with deteriorating hypertension underwent CDU. Seven out of 93 patients (8%) were excluded from the study because of incomplete visualization of the transplant vessels. The CDU diagnosis of TRAS was made when all of the following criteria were present: 1. local increase in flow velocity exceeding 150% of the values found in other sections of the transplant artery and 2. marked turbulences in the artery distally of a region with local flow increase. 86 CDU examinations obtained in 86 patients [52 male, 34 female; mean age 45.7 +/- 12.6 years; examined on average 28.8 months (1-156) after transplantation] were compared with 40 angiographies. Patients showing stenosis in the CDU (n = 12) or receiving combined antihypertensive therapy with 3 or more drugs (n = 28) had an angiography performed. Angiography confirmed 11 out of the 12 arterial stenoses that had been found with CDU and detected one segment artery stenosis of 30-50% that was not detected by CDU. In 4 stenosed arteries, peak velocities were higher than the maximum velocity measurable with the pw-Doppler (higher than 350 cm/s). Peak velocities measured by CDU within 8 stenoses exceeded the flow speeds obtained elsewhere in the artery by 193 +/- 35% (286 +/- 82 cm/s). Using the criteria of stenosis as defined in this paper, CDU may be employed as screening method to detect TRAS with a sensitivity of 92% and a specificity of 96%.

Adult↗
PubMed1993

[Pregnancy after kidney transplantation].

The course of 13 pregnancies in 12 women (mean age 28 [19-34] years) after renal transplantation was analysed retrospectively. The average period from renal transplantation to the beginning of pregnancy was 45 [7-144] months. All patients received methylprednisolone for immunosuppression, while seven each additionally received azathioprine and/or cyclosporin. At the onset of pregnancy the transplant function was good or only slightly impaired in 11 women (serum creatinine 1.3 [0.8-1.8] mg/dl). But in one patient, a diabetic with nephrotic syndrome, serum creatinine concentration was raised to 2.4 mg/dl. In six patients the cyclosporin dosage had to be increased during the pregnancy. Severe complications were: acute rejection in the 16th week of pregnancy; acute renal failure during a recurrence of haemolytic-uraemic syndrome in the 36th week; and severe renal anaemia (haemoglobin 6.7 g/dl). An irreversible rise in creatinine concentration occurred in five women and hypertension got worse in eight. The mean duration of pregnancy was 35.5 (32-38) weeks. The average birth weight was low (1892 g [970-2560 g]): five children were dystrophic. The dystrophy rate was the same under cyclosporin as under the conventional immunosuppressants. The findings indicate that pregnancy after renal transplantation presents a high risk for mother and child. It demands intensive joint care by obstetrician, paediatrician and nephrologist.

Adult↗
PubMed1993

Nephrotoxicity of cyclosporine in humans: effect of cyclosporine on glomerular filtration and proximal tubular reabsorption.

The chronic nephrotoxic effects of cyclosporine (CsA) include proximal tubular atrophy and vacuolization. This study investigated the effect of CsA on renal hemodynamics and segmental electrolyte transport in CsA-treated patients. The clearance of inulin (CIn) and PAH para-amino-hippuric acid (CPAH) was determined; proximal tubular function was studied using a lithium clearance method and calculating tubular phosphate reabsorption per milliliter of glomerular filtrate (TP/CIn). Twenty patients without renal disease were investigated: ten treated with CsA because of nonrenal grafting (group 1) and ten healthy volunteers (group 2). The results obtained were compared with those from 20 renal allograft recipients, of whom ten were treated with CsA and methylprednisolone (group 3) and ten with azathioprine and methylprednisolone (group 4). CIn and CPAH were significantly impaired in patients treated with CsA. No significant impairment of lithium clearance as induced by CsA was observed. The fractional excretion of lithium was slightly increased in patients treated with CsA compared to their respective controls. TP/CIn was lower in graft recipients compared to controls; no impairment of phosphate reabsorption as induced by CsA was found. The fractional tubular excretion of lithium was slightly increased compared to controls, rising evidence that proximal tubular reabsorption of lithium was decreased. Tubular reabsorption of phosphate was not impaired. The decrease in glomerular filtration and renal perfusion during chronic treatment with CsA was accompanied by a reduced proximal reabsorptive capacity, as was shown by lithium clearance. Our data do not support the hypothesis that functional parameters of the proximal tubular system can be used as indicators of CsA-induced nephrotoxicity.

Absorption↗
PubMed1993

Daily subcutaneous administration of recombinant human erythropoietin (rhEPO) in peritoneal dialysis patients: a European dose-response study.

In a prospective randomized open multicenter study, 107 anemic (Hct < = 28%) peritoneal dialysis (PD) patients were treated with s.c. rhEPO daily. The mean observation period was 299 days (range 14-479 days). Patients were randomly assigned to 3 groups with different initial doses: 5 U/kg (G5), 10 U/kg (G10), 20 U/kg (G20). Initial doses were maintained for at least 8 weeks unless the target Hct (30-35%) was achieved earlier. The weekly increase of Hct was significantly (p < 0.05) dose-dependent: 0.19% in G5, 0.5% in G10 and 0.94% in G20. In case of insufficient response (< 0.5% per week), the dose was doubled every 4 weeks. Final doses on achieving the target Hct ranged from 5 to 40 U/kg (median 20 U/kg). The dose was then reduced to 50% and adjusted individually. The median maintenance dose was 9.9 U/kg/day. No tendency towards higher blood pressure or intensification of antihypertensive treatment was observed. When rhEPO is administered daily, 10 U/kg/day (70 U/kg weekly) is the recommended starting dose. The need for higher doses used in unsatisfactory response, should lead to further examination to rule out iron deficiency and other reasons for non-response. The median maintenance dose reported here is the lowest published in the literature for PD patients and seems to be linked to the daily injections.

Anemia↗