[Primary hyperparathyroidism: etiology, diagnosis and treatment]. / Les hyperparathyroïdies primaires: étiologies, diagnostic et traitement.

Primary hyperparathyroidism is a not so infrequent disease that is often overlooked by physicians. Its incidence is estimated to be about 28 in 100.000 subjects, mainly women over seventy years old. Three to four percents of women over seventy are affected. Hyperparathyroidism can be isolated or be a component of a more complex syndrome like multiple endocrine neoplasms (MEN). Patients can be asymptomatic or present with symptoms like asthenia, hypertension or nephrolithiasis. The biological investigation requires the combined measurements of plasmatic ionized calcium and parathormone. In some cases, more specific explorations like calcium loading tests have to be performed in order to confirm the diagnosis.

[How I examine...diabetic nephropathy. Second part: assessment of glomerular filtration]. / Comment j'explore ... la néphropathie diabétique. Deuxième partie: suivi de la filtration glomérulaire.

The natural history of diabetic renal disease can be divided into different stages according to the degree of albuminuria and the level of glomerular filtration rate (GFR). Assessment of the early hyperfiltration state, as well as determination of the rate of decline in kidney function at a later stage require precise and accurate methods to measure GFR. In this article, we briefly remind the reader of the physiological basis of GFR. We then review the different techniques for the monitoring of kidney function (inulin clearance, endogenous creatinine clearance, plasma disappearance of a radiolabelled tracer) and discuss the pro and cons of each of them in different clinical settings. Finally, we try to define a rational use of these techniques in everyday clinical practice.

[Renal functional reserve]. / La réserve fonctionnelle rénale(RFR).

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.

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.

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.

Variability of albumin excretion in insulin-dependent diabetics.

Sixteen adults patients with insulin-dependent diabetes mellitus and 16 healthy controls, matched for sex and age, were asked to collect their urine during the night and during the day at rest, at weekly intervals on four occasions. Subjects with heart failure, kidney disease, hypertension, abnormal urinalysis (Albustix positive) or poorly controlled diabetes prior to entry in the study, were excluded. A high variability in the albumin excretion rates (AER) was observed in both diabetic and control groups but the variance was significantly greater in diabetics. Moreover the variance in AER was higher in daytime as compared to overnight urine collections in both groups. Overnight urine collections are more precise than daytime urine collections for the determination of AER.

[Presence and regulation of plasma with natriuretic and Na-K ATPase inhibitory properties in normotensive subjects]. / Présence et régulation d'une activité plasmatique à vertu natriurétique et inhibitrice de la Na-K ATPase chez des sujets normotendus.

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)

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.

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.

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.

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.

Validation of a simple isotopic technique for the measurement of global and separated renal function.

Schlegel and Gates described an isotopic method for the measurement of global and separated glomerular filtration rate (GFR) and effective renal plasma flow (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. This method requires counting of the injected dose and attenuation correction, but no blood or urine sampling. We validated this technique by the simultaneous infusion of inulin and polycyclic aromatic hydrocarbon (PAH) in patients with various levels of renal function (anuric to normal). To better define individual renal function we studied 9 kidneys in patients either nephrectomized or with a nephrostomy enabling separated function measurement. A good correlation between inulin, PAH clearance, and isotopic GFR-ERPF measurement for both global and separate renal function was observed.