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Biomedical subjects

G Dongradi

Publications and source records attributed to G Dongradi.

At least 19 recordsLinked to original sources
PubMed1991

Phosphate kinetics in dialysis patients.

During extrarenal therapy, plasma phosphate concentrations have specific kinetics: plasma values reach a steady-state nadir 90-120 min after the beginning of the session (from 0.6 to 1.1 mmol/l) with a subsequent high rebound in the 3-4 h following the session. These kinetics are found during haemofiltration (HF) with high ultrafiltration (UF) rates (greater than 270 ml/min) and UF volumes (greater than 30 1). Other HF studies with different UF rates (100 or 200 ml/min) show that delayed mass transfer cannot explain kinetics which result from a phosphate transfer from cellular to extracellular space. Acetate or bicarbonate reinjection fluid does not modify phosphate kinetics. Immediate decrease of ionised calcium after the session argues against a mobilisation from the exchangeable phosphate pool of bone. Only potassium shows a similar pattern to phosphate, so the hypothesis of a relation between cellular phosphate and potassium fluxes is postulated. 31P-NMR study during and after HF does not allow us to specify phosphate transfer from the cell, but various potassium concentrations in the reinjection fluid (0, 2, 3.5, or 4 mmol/l) confirm the influence of potassium removal on phosphate transfer, and a significant linear relationship can be established between cellular potassium and phosphate fluxes. The influence of phosphate removal on phosphataemia has also been investigated using 0, 2, or 3 mmol/l phosphate in the reinjection fluid. Whatever the phosphate modification achieved by the session, the patient's phosphate concentrations are not significantly different 2 days later.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemofiltration↗
PubMed1985

Arteriovenous shunt measured by bolus dye dilution: reproducibility and comparison between two injection sites.

Twenty-eight brachial arteriovenous fistulae (AVF) flows were assessed by the Stewart and Hamilton method by bolus dye injection. These measurements were divided in two groups: a first group with dye injection into the AVF artery and a second group with dye injection into the efferent vessel of the AVF in close proximity. The increase and the decrease of dye concentration were regular and the circulation occurred very late in both groups. Reproducibility was assessed by the usual index: the mean of the differences between two successive measurements of each series related to the first of these two and expressed as a percentage, m(Qn - Qn - 1)/Qn%. In the two groups, the reproducibility index was at 10.1%, similar to the index applied to Grimby's results, measuring successive cardiac output by dye bolus injection at 9.8%. Theoretical criteria of validity of the Stewart and Hamilton method were checked for all measurements. Even when the duration of the measurement was very short, arteriovenous flow fulfilled the criteria of validity in the same way as cardiac output. Two AVF flows were measured successively at both injection sites with no difference between the obtained values. The same reproducibility of the efferent vessel injection site group suggests that an arterial puncture is not necessary for a correct assessment of AFV flow.

Adult↗
PubMed1985

Technical and clinical data on high-performance hemofiltration: twelve patients during one year.

In 12 chronic hemodialysis patients, postdilutional hemofiltration (HF) was substituted for conventional acetate hemodialysis (HD) (4-5 h/session with high-area capillary dialyzers). In HF, the purposes were to obtain (a) no increase in pre-HF uremia compared with pre-HD uremia (high ultrafiltrate volume), (b) an HF duration shorter than that of HD (mean ultrafiltrate rate greater than 120 ml/min), (c) a disposable cost of an HF session identical to that of an HD session (reuse of hemofilters and extemporaneous preparation of substitution fluid). One-year results were (a) an ultrafiltrate volume of 26.8 L/session and a pre-HF uremia of 35.4 mmol/L (pre-HD uremia 34.0 mmol/L), (b) a mean ultrafiltrate rate of 143 ml/min and a mean HF duration of 190 min (mean HD session duration 250 min), and (c) better clinical tolerance and vascular stability in HF than in HD (weight loss 3.5 kg in HF and 3.0 kg in HD). Reuse of filters and extemporaneous preparation of substitution fluid were not responsible for any pyrogen reaction or bacterial contamination. In conclusion, (a) compared with conventional HD, high-flux HF results included identical removal of small molecules, improvement in vascular stability, decrease in session duration, and identical disposable cost; (b) routine high-flux HF is workable in a dialysis unit; (c) vascular access is the most important limiting factor to high-flux HF. Today 30-40% of patients can be treated with this method.

Adult↗
PubMed1983

Peliosis hepatis in a chronic hemodialysis patient.

Peliosis has been described rarely in patients with chronic renal failure. The case reported shows the difficulty of diagnosis in a chronic hemodialysis patient with painful hepatomegaly, chronic ascites and cachexia. The rarity of this lesion under such circumstances, if the etiologies described in the literature are taken into account, is discussed.

Biopsy↗
PubMed1983

Plasma kinetics of small molecules during and after hemofiltration: decrease in hemofiltration efficiency related to increase in ultrafiltration rate.

The influence of delay in mass transfer on the real efficiency of hemofiltration sessions (HF) was studied in 7 patients during HF at a moderate ultrafiltration rate (UF rate = 100 ml/min) and at a high UF rate (UF rate = 200 ml/min). Real efficiency was expressed as "effective clearance" (KE) and compared to plasma clearance (KP); KE/KP was calculated from the kinetics of small molecules during HF and stabilized rebound post HF. Rebound in urea and uric acid plasma levels stabilized by 90 min post HF; increase in the UF rate from 100 to 200 ml/min was responsible for a decrease in KE/KP of 4% for urea and 11% for uric acid. Plasma creatinine and phosphorus levels had not stabilized by 90 min post HF, and it was thus impossible to calculate effective clearance; on the other hand, the magnitude of the rebound phenomenon for these two molecules was considerably greater than for uric acid. The magnitude of the post HF rebound for creatinine and phosphorus might be associated with delayed diffusion from a bound form in the intracellular space.

Blood↗
PubMed1981

[Arterial hypertension due to abuse of sympathomimetic drugs. One case (author's transl)].

A 36-year-old woman developed severe arterial hypertension after taking for five consecutive years increasing dose (up to 10 mg per day) of phenoxazoline HCl in nasal spray. A relationship between the abuse of this sympathomimetic drug and the hypertension was suggested by the unusual appearance of renal arteries on arteriography (stenosis and dilatations resembling aneurisms), the increase in renin activity and the disappearance of hypertension after the drug was discontinued. On control examination, two years later, blood pressure, renin activity and renal arteries were normal. The possibility of sympathomimetic drug overdosage must be borne in mind in cases of suspected iatrogenic arterial hypertension.

Adult↗
PubMed1981

[Left ventricular performance in chronic hemodialysis patients studied during intense exercise and during a dextran infusion test (author's transl)].

In 14 chronic hemodialysis patients with recent circulatory pulmonary congestion or pulmonary edema, left ventricular failure was suspected. Left ventricular function was studied by a sitting exercise test and a dextran infusion test. According to the left ventricular function curves the left ventricular function was not altered in chronic hemodialysis patients compared to normal subjects. It is possible that on average the left ventricular performances is higher in chronic hemodialysis patients than in normal subjects. These results indicate that circulatory pulmonary congestion and pulmonary edema are not reliable signs of left ventricular failure in chronic hemodialysis patients.

Adult↗
PubMed1981

Hemodynamic effects of arteriovenous fistulae in chronic hemodialysis patients at rest and during exercise.

The effects of arteriovenous fistulae (AVF) on cardiac output (CO) and cardiac filling pressures were studied at rest and during exercise in 16 chronic hemodialysis patients. After the occlusion of the AVF, average CO fell but cardiac filling pressures remained unchanged, seven patients had a drop in CO greater than or equal to 1.0 l/min (group A) and nine patients had a drop in CO less than or equal to 0.9 l/min (group B). At rest, average CO was higher in group A than in group B, but cardiac filling pressures were the same in group A and in group B. During maximal exercise, average CO and cardiac filling pressures were the same in both groups.

Adult↗
PubMed1981

[Radiological, fibroscopical, histological and secretory gastric aspects in hemodialyzed patients (author's transl)].

Seventeen chronic hemodialyzed patients underwent a baryum meal, a fibroscopy with biopsic studies and an evaluation of gastric acid secretion. No duodenal ulcer was found. The gastric and duodenal folds are the most common anomaly. It has been not possible to correlate these folds to a precise histological entity. None of these patients exhibited an hypersecretory state, on the other hand 3 of them were hyposecreting. A statistical relationship between BAO on the one hand and PTH, CT and Ca on the other hand was found.

Adult↗
PubMed1981

High efficiency haemofiltration (ultrafiltration of more than 250ml/min for two hours) in eight uraemic patients.

In eight uraemic patients a haemofiltration of very high efficiency was carried out from a double extracorporeal circuit set up via an arteriovenous fistula. The weight of the patients was kept constant throughout the session. The average ultrafiltration flow rate was 274ml/min; the total ultrafiltration volume was 32.9L/min. The clinical tolerance was very good. The loss of efficiency associated with the magnitude of the ultrafiltration volume and with the diffusion delay of the removed molecules was evaluated at 9 per cent for urea and 17 per cent for creatinine. In spite of a considerable phosphorus depletion no severe hypophosphoraemia was observed; the stable value of the phosphoraemia between the 90th and the 120th minute of the session suggests the existence of a physico-chemical balance around the value of 0.74mmol/L.

Adult↗
PubMed1978

[Patients on chronic hemodialysis. Hemodynamic study at rest and during exercise before dialysis, in hypertensive and normotensive patients (author's transl)].

In twenty chronic hemodialyzed patients a hemodynamic study was carried out just before dialysis at bed rest and during sitting bicycle exercise. At bed rest, cardiac index (mean +/- standard deviation = 5.2 +/- 1.1/mn/m2) and pulmonary wedge pressure (17.4 +/- 6.8 mmHg) were increased. At the highest level performed (60 ou 90 W) cardiac index increased in all patients and reached on average normal values as compared to normal sedentary subjects, but heart rate less increased than in normal subjects during maximum effort. These data suggest that these patients had no patent heart failure. Pulmonary wedge pressure was more increased in hypertensive patients (20.7 +/- 6.7 mmHg) than in normotensive patients (13.3 +/- 4.4 mmHg). Since cardiac index was similarly increased in both groups of patients the higher values of pulmonary wedge pressure in hypertensive patients could be related to either an increase in total blood volume, or a reduction in left ventricular compliance or an increase in cardiopulmonary blood volume.

Adult↗
PubMed1978

[Relationship between gastric acid secretion and plasma calcium, parathormone and calcitonin levels in patients with chronic renal failure on haemodialysis (author's transl)].

In twelve patients on chronic haemodialysis, a relationship was established between gastric acid secretion on the one hand, and certain parameters of calcium metabolism on the other hand: in a multifactorial statistical analysis, plasma calcium before dialysis (p less than 0,05), plasma parathormone levels before dialysis (p less than 0,05) and plasma calcitonin before dialysis (p less than 0,05) were variable explicatives of basal gastric acid secretion according to a direct relationship, whilst plasma calcium (p less than 0,05) was the only explicative variable of maximal gastric acid secretion after pentagastrin, with an inverse relationship. These preliminary results suggest that gastric acid secretion in the haemodialysis patient must be interpreted in the light of the state of calcium metabolism. Thus hypocalcaemia may be accompanied by decreased basal acid secretion and by contrast by an increased maximal acid secretion. These results require confirmation in a larger number of patients.

Adult↗