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Biomedical subjects

J P Godon

Publications and source records attributed to J P Godon.

At least 19 recordsLinked to original sources

[Renal functional reserve].

The concept of renal functional reserve (RFR) was introduced in the 80's. The renal functional reserve was defined as the ability of the kidney to increase Renal Plasma Flow (RPF) and Glomerular Filtration Rate (GFR) after a stimulus as a protein load. The absence of RFR defines a state of hyperfiltration which seems to be a detrimental factor for the progression of renal failure. The measure of RFR by a protein load test is thus a mean to detect glomerular hyperfiltration and allows to give adequate diet prescription.

Atrial Natriuretic Factor

Diagnostic criteria of analgesic nephropathy in patients with end-stage renal failure: results of the Belgian study.

Diagnostic criteria of analgesic nephropathy with well-defined sensitivity and specificity are not available. During a 2-year period all new patients (n = 273) starting renal replacement therapy in 13 Belgian dialysis units were investigated aiming to select diagnostic criteria of analgesic nephropathy with acceptable performance. Using several interview techniques, a history of analgesic abuse was found in 31% of the patients. Analgesic abusers presenting a clear non-analgesic-related renal diagnosis were excluded from analysis (n = 25). Comparing the remaining abusers (n = 60) and patients without a history of analgesic abuse (n = 188) it was found that renal imaging investigations (sonography plus tomography), showing a decrease in length combined with bumpy contours of both kidneys, presented a sensitivity of 90% and a specificity of 95%. The additional finding of signs of renal papillary necrosis resulted in an overall sensitivity of 72% and a specificity of 97%, giving a positive predictive value of 92%. Other signs frequently mentioned in the literature (hypertension, anaemia, sterile pyuria, bacteriuria, proteinuria) showed insufficient sensitivity and/or specificity to be of help for diagnosing analgesic nephropathy in end-stage renal failure (ESRF) patients starting renal replacement therapy.

Adult

Serum beta 2-microglobulin levels in chronic post-transfusion non A non B liver disease.

Serum beta 2-microglobulin (beta 2 mu), a reliable marker of T-cell activation, was measured in 25 patients with chronic post-transfusion non A non B (NANB) liver disease and in 21 patients with HBsAg positive chronic liver disease. beta 2 mu levels were elevated in NANB patients when compared with controls but not in comparison with the HBsAg carriers. In NANB patients, beta 2 mu concentrations were significantly correlated with serum IgG (P less than 0.001) and with circulating immune complex activity, assessed by the 125IClq binding test (P less than 0.01). These findings suggest that, in addition to T-cells, the B-cells contributed also to the beta 2 mu production. Patients with "active disease" (chronic active hepatitis and active cirrhosis) had significantly higher beta 2 mu levels (P less than 0.001) than did those with "inactive disease" (chronic persistent hepatitis and inactive cirrhosis). This relation of serum beta 2 mu concentrations and histological activity was also observed in the HBsAg carriers and suggests that the course of post-transfusion NANB chronic hepatitis could be determined by host's immune response rather than by a direct effect of the virus.

Adult

[Presence and regulation of plasma with natriuretic and Na-K ATPase inhibitory properties in normotensive subjects].

In hypertension, mainly low renin subjects, a plasma Na-K ATPase inhibitor has yet been demonstrated. Moreover, it has been established that the concentration of this activity may be modulated by variations of the sodium and water balance. In the present study, such an activity and its role has been searched in the plasma of young healthy normotensive population. Its potential natriuretic property has also been tested. Twenty male subjects, younger than 30, volunteered 3 very different sodium diets: normal (+/- 170 mM/d), very low (-20 mM/d) and very high sodium intake (+340 mM/d). At the end of each period, some clinical and biological parameters have been studied: blood pressure, weight, vascular resistances and reactivity to norepinephrine, 24 h natriuresis, and plasma renin activity. Furthermore, the plasma natriuretic activity has been tested after filtration of the plasma across different Amicon filters to measure the effect of plasma extracts from 500 to 10,000 daltons (LMW) on fractional sodium excretion (FENa) after injection of such extracts in vivo in rat renal artery. For detection of a plasma Na-K ATPase inhibitor activity, 1/5 th diluted fresh plasma and LMW extracts have been incubated with purified rabbit renal Na-K ATPase enzyme and compared with the activity of this enzyme without such an incubation of plasma. We have observed that when the amount of sodium in the diet is higher, weight, systolic blood pressure, and vascular reactivity to norepinephrine increase. In the same condition, there are greater natriuretic activity in the LMW extracts and Na-K ATPase inhibitor activity in fresh plasma and LMW extracts of the normotensive people.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Effect of haemodialysis on upper gastrointestinal tract pathology in patients with chronic renal failure.

Upper gastrointestinal tract pathology observed at autopsy in 94 patients with end-stage renal disease (GFR less than 10 ml/min) was analysed retrospectively. To better evaluate the effect of haemodialysis on this pathology, the chronic renal failure patients were subdivided into three groups: 19 patients who had died before haemodialysis treatment could be undertaken (group I), 21 patients who had died during the first month (group II), and 54 patients who had died after at least one month of haemodialysis treatment (group III). The results revealed that the number of patients with upper gastrointestinal tract pathology was significantly higher in groups I and II (58% and 57% respectively) as compared to group III (31%) and controls (35%). No difference could be demonstrated between group III and controls. The most prevalent lesions observed were gastritis, followed by gastric and peptic ulcers. The incidence of this pathology appeared to decline as the duration of dialysis therapy increased. Mortality caused by upper gastrointestinal tract pathology remained high during the first two years of treatment in group III, despite a smaller incidence of upper tract lesions. This was explained by a relatively higher proportion of haemorrhage.

Cross-Sectional Studies

Rapid method for the measurement of differential renal function: validation.

The precise measurement of glomerular filtration rate (GFR) and renal plasma flow (ERPF) usually requires continuous intravenous administration of adequate substances, with multiple blood and urine analysis, and does not allow measurement of separate renal function. Schlegel et al. and Gates described isotopic methods for the measurement of global and unilateral GFR and ERPF based on the determination by scintillation camera of the fraction of the injected dose ([99mTc]DTPA-[131I]hippuran) present in the kidneys 1-3 min after its administration. These methods require counting of the injected dose and correction for attenuation, but no blood or urine sampling. We have validated these techniques by simultaneous infusion of inulin and PAH in patients with various levels of global renal function (anuric to normal). To better define unilateral renal function we have also studied nine kidneys in patients either nephrectomized or with a nephrostomy enabling unilateral function measurement. A good correlation between inulin or PAH clearances and fractional uptake of [99mTc]DTPA or [131I]hippuran by the kidney was observed. Very good reproducibility of both isotopic techniques was shown. We conclude that determination of the fractional uptake of [99mTc]DTPA and [131I]hippuran between 1 and 3 min allows good and reproducible prediction of global and especially of unilateral kidney function with great rapidity and simplicity, rendering this technique suitable for clinical practice.

Adult

Impaired sodium excretion in experimental glomerulonephritis: an explanation for the controversies in the literature.

Considerable discrepancies exist in the literature concerning Na excretion by the rat kidney in experimental antiglomerular basement membrane (GBM) glomerulonephritis (GN). Previous studies in our laboratories demonstrated a disturbance in Na excretion with an impaired absolute (UNa X V) and fractional (FENa) excretion of Na after saline loading. However, most of the other authors in the literature failed to observe similar findings. The present study was undertaken to elucidate some of these controversies: We showed that a difference in Na excretion between anesthetized GN and normal rats might not be detected after a volume expansion if the latter is small or slow (FENa in GN 2 +/- 0.1%, in normals 2 +/- 0.2%; not significant). Only a rapid and important volume expansion is sufficient to unmask such a difference between the two groups (FENa 3 +/- 0.3 and 6 +/- 1%, respectively, p less than 0.001), and detect an impaired Na excretion in GN animals. The same amount of NaCl was nevertheless administered during slow and rapid volume expansion. Similarly, in GN conscious rats only after a saline load or repeated water loads did we observe a significantly smaller UNa X V compared to normals while no difference was present between the two groups after a single water load. In the literature, all the authors, that failed to demonstrate a disturbance in Na excretion in anti-GBM GN, administered slow and small isotonic saline loads to their rats. The hypothesis we formulate to explain these controversies is that the nonobserved disturbance in sodium excretion in most of these studies is probably secondary to insufficient natriuretic stimuli.

Animals

Arguments for the presence of a Na-K ATPase pump inhibitor in the plasma of uremic and essential hypertensive patients.

The effect of salt and/or volume depletion has been tested in 6 end-stage renal disease and 11 essential hypertensive patients (HTA) on red blood cell (RBC) ionic fluxes. Volume depletion promotes an increase in the RBC Na-K ATPase activity with, as a result, a significant decrease in intracellular sodium concentration [Na)ic). Moreover, a factor has been found in the plasma of uremic subjects which causes natriuresis when injected in rat renal arteries. The concentration of this factor decreases during dialysis in relation to the weight loss and the increase in the RBC Na-K pump activity. In essential hypertension, the effect of a low salt diet on the blood pressure is correlated with the improvement of RBC Na-K ATPase activity. These experiments illustrate the presence of a Na-K ATPase inhibitor in the plasma of these subjects, dependent on sodium and water balance.

Adult

Distal blockade in experimental glomerulonephritis: the role of the diluting segment in sodium retention.

In the light of accumulating evidence implicating the diluting segment as the site of final regulation of sodium excretion by the nephron, we produced in this experiment distal blockade in anti-glomerular basement membrane (GBM) glomerulonephritic (GN) rats by the administration of furosemide and polythiazide. This allowed to dissociate the sodium reabsorption that occurs in the proximal tubule from the one that occurs more distally and permitted an appreciation of the rôle played by the diluting segment in the sodium retention of anti GBM GN. In a previous experiment we showed that GN conscious or anaesthetized rats presented an increase in Na tubular reabsorption and failed to raise their fractional and absolute excretion of sodium as normal one did after rapid volume expansion. In this study distal blockade corrected almost completely the difference in sodium excretion that existed between GN and normal groups before the administration of diuretics, pointing to the important rôle played by the diluting segment in the sodium retention of experimental GN.

Anesthesia

Erythrocyte sodium-potassium activities, plasma natriuretic activity, and peripheral vascular resistances during hemodialysis or hemofiltration.

The effect of hemodialysis (acetate buffer) or hemofiltration on blood pressure, heart rate, peripheral vascular resistances, red blood cells ionic fluxes, and plasma natriuretic activity has been studied in six male patients treated for end-stage renal disease. The hemodynamic response to these two modes of treatment markedly differs. Whereas, peripheral resistances increase and heart rate is not affected during hemofiltration, a decrease in blood pressure, tachycardia, and vasodilation is observed during hemodialysis. However, in both therapeutic approaches, red blood cell ouabain-sensitive sodium-potassium pump activity increases in a similar way, and the plasmatic natriuretic activity decreases, whereas the vascular response to norepinephrine is reduced. All of these changes were strongly correlated to the amount of fluid removed. The natriuretic activity may thus play a role in the regulation of blood pressure and hemodynamic adjustments to fluid removal in chronic renal failure between two dialyses, but its action is not predominant during the dialysis session itself.

Adult