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F Reinbold

Publications and source records attributed to F Reinbold.

8 recordsLinked to original sources
PubMed2000

Afferent-efferent vessel dysfunction appears to be a specific characteristic of a large subset of patients with essential hypertension.

Exercise renography makes it possible to subdivide essential hypertensives (EHs) into two distinct populations. Fifty to 60% develop exercise-mediated renal dysfunction and a transitory, severe reduction of glomerular filtration. The other subset of EHs does not have exercise-mediated renal dysfunction. We hoped to learn whether the disturbance is also present while EHs rest. Twenty-six EHs and 21 normotensive controls were studied with a resting sequential renogram using Tc-99m-mercaptoacetyl-triglycine (MAG3), a tracer excreted primarily by proximal tubular cells. EHs also had an exercise renogram. All persons had three consecutive 10-min dual-tracer infusion clearance determinations with 111In-DTPA and 131I-hippurate, for the simultaneous determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). To demonstrate the accuracy of the clearance procedure we sought to reproduce Hollenberg's results which show greater flow variability in EH than in normotension. Following this, the variability (VAR) of the GFR and ERPF as well as the variability fraction (VF), the ratio of GFR variability divided into the ERPF variability, were calculated. Hollenberg's results were reproduced. Sixteen of 26 essential hypertensives developed exercise-mediated renal dysfunction. GFR-VAR in EH differed from controls. The VF suggests that EHs with a bilateral abnormal exercise renogram have a more pronounced GFR variability than those EH with a normal exercise renogram. The results point to intraglomerular pressure fluctuations in patients with EH, and the VF suggests that this may be more pronounced in EHs with a bilateral abnormal exercise renogram than in those with a normal exercise renogram. It is hypothesized that the variable GFR provokes renin secretion in EH.

Adult↗
PubMed1996

Exercise activates renal dysfunction in hypertension.

A bilateral, exercise-mediated renal functional abnormality was first described more than a decade ago. The disturbance is specific for hypertension, is seen in different forms of hypertension, and has been studied most extensively in hypertensives with renovascular disease. The bilateral-abnormal exercise renogram identifies the disturbance. Hypertensives with unilateral renovascular disease were studied in the continuing evaluation of the bilateral function disturbance. We examined 31 hypertensives with documented unilateral renovascular disease, all of whom had renography at rest and during 60 to 80 W ergometric exercise. An additional seven normotensives and 17 essential hypertensives served as controls, and had the same sequence of studies. All patients reported upon continued on to an infusion clearance with 131I-hippurate and 111In-diethylenetriamine pentaacetic acid to determine glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) at rest, and during 25 W ergometric exercise. Eighteen of 31 hypertensives with unilateral renovascular disease were found to have a bilateral-abnormal exercise renogram. Clearance examinations in these identified a prominent reduction of the GFR and a lesser decrease in the ERPF during exercise. Hypertensives with normal exercise renograms did not have the exercise mediated abnormal clearance pattern. Similar results were observed in the control population of essential hypertensives, 65% of whom developed the functional disturbance. The seven normotensives controls did not exhibit the exercise mediated function changes. We conclude that an exercise-mediated bilaterally occurring functional disturbance exists in certain hypertensives, who then have a bilateral-abnormal exercise renogram. Associated with this is a distinctly abnormal clearance during exercise which is characterized by a low filtration fraction.

Antihypertensive Agents↗
PubMed1993

Renovascular hypertension: a perfusion disturbance that escaped recognition.

A bilateral, exercise-mediated, hippurate transport disturbance was previously described when patients with fixed renovascular hypertension were imaged with o-iodo-hippurate. This study sought to test the hypothesis that patients with an abnormal exercise scintigram have a perfusion abnormality characterized by dysregulation of renal blood flow. We imaged 23 patients with hypertension and angiographically documented renovascular disease in the supine position, as well as during upright exercise. Seven normotensive volunteers served as controls. We measured the resting glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) with a single compartment radiotracer infusion clearance. The clearance examination also included a measurement period with 25 watt ergometric exercise. Nine hypertensive patients had normal exercise renograms. These patients had age-appropriate clearance values at rest and during exercise, as well as age-appropriate best-organ (generally without stenosis) GFR and ERPF values. The filtration fraction (FF) was 0.21 at rest and 0.22 during exercise. Fourteen hypertensive patients had a bilateral, exercise-induced disturbance of hippurate transport. In these patients, the global resting GFRs and ERPFs were decreased 40% from age-appropriate predicted values. The FF remained at 0.20. Light exercise caused a pronounced contraction of GFR and a less severe reduction in the ERPF. During exercise the mean filtration fraction was only 0.12. The exercise-induced reduction in the clearance values was bilateral, which indicated that the perfusion of nonstenosed organs was compromised as well. We suggest that the described perfusion abnormality occupies a relevant position during the maintenance phase of fixed renovascular hypertension.

Adult↗
PubMed1988

Technetium-99m labeled renal function and imaging agents: I. Clinical evaluation of 99mTc CO2-DADS-A (99mTc N,N'-bis-(mercaptoacetyl)-2,3-diaminopropanoate).

Animal experiments and preliminary clinical results showed that the N2S2-complex 99mTc CO2-DADS-A, which was claimed to be a potential replacement for o-I-hippurate as a renal function agent, had a lower affinity for the tubular transport system than o-I-hippurate. In order to evaluate if this finding offered the possibility of detecting decreases in tubular function with more sensitivity, or at earlier times, 6 patients in the early post-transplantation period were subjected to 53 simultaneous scintigraphic investigations with 131I o-I-hippurate and 99mTc CO2-DADS-A. The comparison of the renograms obtained with the respective agents showed that in almost all cases of acute graft rejection only o-I-hippurate yielded the typical, diagnostically useful accumulation curve which results from its high retention in the kidney parenchyma. 99mTc CO2-DADS-A did not reveal this effect. Additionally the plasma clearance of each agent was measured simultaneously under steady state conditions in nine patients. Although it was reported that relative to o-I-hippurate the analog images obtained with 99mTc CO2-DADS-A gave higher kidney-to-background ratios and the amount excreted in the urine at 30 min was slightly less, the clearance values obtained for 99mTc CO2-DADS-A were on average only 36% of those for o-I-hippurate. It is concluded that 99mTc CO2-DADS-A is not suitable as a substitute for o-I-hippurate.

Alanine↗
PubMed1988

Technetium-99m labeled renal function and imaging agents: II. Clinical evaluation of 99mTc MAG3 (99mTc mercaptoacetylglycylglycylglycine).

First clinical results indicated that among all potential 99mTc-complexes the N3S-complex 99mTc MAG3 has the biokinetic properties most similar to o-I-hippurate (OIH). A simultaneous comparison of 99mTc MAG3 and 131I OIH was conducted in a series of 48 patients. Twelve out of 18 transplant patients received simultaneously both radiopharmaceuticals for follow-up scintigraphic studies during the early post-transplantation period. In all of these double tracer studies (n = 90) the renograms obtained with 99mTc MAG3 exhibited qualitatively the same curve-shapes, compared with OIH, in cases of acute graft rejection or acute tubular necrosis. In addition, both agents were administered simultaneously to 46 of these patients and the plasma clearance values were determined under steady state conditions. The clearance data of both radio-pharmaceuticals showed a very good correlation (r = 0.95; P less than or equal to 0.05). The 99mTc MAG3/131I OIH clearance ratio showed a mean value of 0.65. Due to the high plasma protein binding of 99mTc MAG3 it is assumed not to be filtered through the glomerular membrane. Therefore we introduce for the 99mTc MAG3 clearance the term "Tubular Extraction Rate (TER)". Due to the favourable physical characteristics of 99mTc, higher activities can be administered as compared to 131I OIH. This allows the simultaneous examination of the tubular function as well as the renal perfusion. Additionally the kidney morphology is imaged with much better resolution. It is concluded that from the clinical point of view 99mTc MAG3 is a favourable replacement for OIH not only for renal imaging but also for the quantitative determination of tubular function. The acceptance will depend on the quality and on the handling of a commercially available kit formulation.

Animals↗
PubMed1985

Estimating the effective renal plasma flow from the hippurate renogram.

A method for estimating the effective renal plasma flow (ERPF) from renograms is presented. Renograms obtained in 91 patients were used to test the method. The clearance values derived from renography were compared with those obtained with infusion clearance. It was shown that the ERPF was able to be estimated from the renogram with a standard error of +/- 94 ml min-1.

Glomerular Filtration Rate↗