Functional evaluation of normal and ischemic kidney by means of gadolinium-DOTA enhanced TurboFLASH MR imaging: a preliminary comparison with 99Tc-MAG3 dynamic scintigraphy.

The functional value of TurboFLASH MR imaging in the assessment of dynamic contrast enhancement and renal perfusion anomalies was evaluated in seven patients, who also underwent renal scintigraphy in baseline conditions. The basal renograms obtained from MAG-3 scintigraphy (mercapto acetyl triglycine, MAG3-S) and from Gd-DOTA-enhanced turboFLASH MRI were compared. After hydration, the protocol used consisted in breath-hold coronal turboFLASH acquisitions after IV bolus of Gd-DOTA (4 s every 20 s during 10 min) for MRI, and IV bolus of 370 MBq of 99mTc-MAG3 followed by 60 frames of 1 s and then 120 frames of 10 s for MAG3-S. Relative renal functions were computed for both methods by calculation of the integral of the uptake phase between the first and the second minute. Renograms exhibited 10 normal and 4 ischemic kidneys. There was a close correlation between the contrast enhancement of MRI and isotopic uptake in normal and ischemic kidneys. Global renograms of MRI correlated with MAG3-S (r = .82, p < .001) with similar curve shape and time to peak. Relative renal function of the right and left kidney were closely correlated in all patients (r = .98, p < .001), although there was a tendency for MR to overestimate MAG3-S evaluation in kidneys with severe basal dysfunction. Enhanced turboFLASH provides noninvasive assessment of renal perfusion in patients with renovascular disease. Accurate renograms are obtained with dynamic-enhanced MRI, but the relative renal function seems to be overestimated in low values of ischemic kidneys, and needs further comparative evaluation.

Pyrazinamide and pyrazinoic acid pharmacokinetics in patients with chronic renal failure.

Pharmacokinetics of pyrazinamide and its major metabolite, pyrazinoic acid, were assessed in 10 chronic uremic patients treated by maintenance hemodialysis in comparison with 10 normal subjects. All subjects ingested a single dose of 1 g of pyrazinamide, the patients receiving the drug immediately after the end of a dialysis session. Bioavailability of pyrazinamide was only slightly increased in patients, its dialysis extraction coefficient being 55.3%. In contrast, pyrazinoic acid has an elimination rate-dependent metabolism with a bioavailability markedly increased in patients and a dialysis extraction coefficient of 59.8%. These data may lead to recommendations of a reduction in the dosage of pyrazinamide in dialysis patients. However, administering the usual dosage of the drug at the end of each dialysis session seems preferable to the daily administration of a reduced dosage.

Changes in erythromycin pharmacokinetics induced by renal failure.

As erythromycin ototoxicity appears to be favored by renal insufficiency, its pharmacokinetics were assessed in chronic uremic patients treated by maintenance hemodialysis in comparison with normal subjects. Two groups of 8 patients each were studied, the first one on an interdialytic day, the second immediately after the end of an hemodialysis session. All subjects ingested a single dose of 1 gram of erythromycin ethylsuccinate. Times of peak serum concentration and biological half-lifes were similar in patients and in controls. Maximum serum concentrations and areas under the serum concentration time-curve were higher in patients than in controls whereas apparent oral clearances were lower in the former. The differences between the two groups of patients were not significant. These pharmacokinetic changes are suggestive of an enhanced bioavailability of erythromycin in chronic renal failure which might predispose uremics to the ototoxicity of the drug.

[Pheochromocytoma, first manifestation of Von Hippel-Lindau disease: a possibility to be considered]. / Phéochromocytome, première manifestation de la maladie de von Hippel-Lindau: une éventualité à connaître.

Von Hippel-Lindau (VHL) disorder is an autosomal dominant disease characterized by the almost constant development of hemangioblastomas in the central nervous system (cerebellum, spinal cord and retina). In addition, various types of tumors including renal cell carcinomas, pancreatic cysts and pheochromocytomas are frequently observed in VHL gene carriers. Linkage of the VHL locus to the RAF-1 oncogene on the short arm of chromosome 3 (3p25-26) has been recently reported. Pheochromocytoma is of particular interest because of the risk of inaugural malignant hypertensive crisis but especially because of a great degree of interfamily variability (from 0 to 92% of affected members in previously reported large kindreds). We have studied a French series of 25 pheochromocytoma (11 males, 14 females) in VHL affected patients. Twenty pheochromocytoma (80%) occurred in a familial context, whereas 5 (20%) were consistent with "apparent sporadic cases". The mean age at pheochromocytoma diagnosis was 27 years (5-55 years). Bilateral tumours have been documented in 13 cases (52%). The prevalence of pheochromocytoma revealing VHL was 14 out 25 (56%). In these cases, VHL diagnosis was considered up to 25 years later. In 6 cases (2 deceased) pheochromocytoma was the only manifestation of VHL. Thus, search for VHL must be systematic in the presence of pheochromocytoma, in the interest of the patients themselves and of potential at-risk family members (prevention of hypertensive crisis linked to latent tumours). Basic check-up (neurological and somatic examination, ophthalmoscopy, familial inquiry) may be completed with cerebral CT scan or MRI and abdominal ultrasonography followed, if positive or doubtful, by abdominal MRI or selective angiography.

[Vesical amyloidosis. Apropos of a case and a review of the literature]. / L'amylose vésicale. A propos d'une observation et revue de la littérature.

A case of primary localized amyloidosis of the bladder in a 60 years old male is described. The initial symptom was hematuria. Cystoscopy revealed a redish angioma-like lesion on the trigone, and the diagnosis was pointed out with biopsy, complementary data, and a close follow-up during two years. In the literature we found 47 cases of primary localized amyloidosis of the bladder and 10 others cases of amyloidosis of the bladder which were part of generalized amyloid disease. The interest of the Wright's special staining method is underlined specifying, on light microscopic study, the AA or AL type of the amyloid disease.

[Fibrillary glomerulopathies]. / Glomérulopathies fibrillaires.

Fibrillary glomerulonephritis is characterized by the presence, mainly in the mesangium, of fibrils demonstrated by electron microscopy of the renal parenchyma. There are several varieties of this disease, depending on the size and, above all, the composition of these fibrils. Thus, fibrillary glomerulonephritis in which the fibrils are made of the normal glomerular basement membrane components can be distinguished from a more frequent variety in which the fibrils are composed of circulating proteins deposited in glomeruli. For a long time, amyloid glomerular nephropathy has been the sole representative of the latter variety, but we now know that, beside renal amyloidosis, there is a non-amyloid fibrillary glomerulonephritis the fibrils of which are made of monoclonal or non-monoclonal immunoglobulins. If it were confirmed that the principal member of this variety, described as immunotactoid glomerulopathy, is frequently associated with monoclonal gammapathy, it would represent, together with amyloidosis and light chain deposition, another variety of glomerular lesions which may occur in monoclonal gammapathy.

[Components of the classical complement pathway in systemic lupus erythematosus]. / Les composants de la voie classique du complément au cours du lupus érythémateux disséminé.

Measurements of complement components in sera from patients with systemic lupus erythematosus (SLE) and some of their relatives indicated that decreased levels of CH50, C4 and C2 were mostly related to a genetic deficiency at one or both of the loci coding for C4, at least in those patients in whom decreased C4 levels were associated with normal C1 hemolytic activity. C4 deficiency is either isolated or associated with complement activation. In some patients with C4 deficiency, complement activation could only be demonstrated by measuring plasma level of the C3 cleavage fragment, C3a des Arg. Decreased concentration and/or hemolytic activity of C4 and C2 in SLE cannot be used to assess the activity of the disease.

[Renal complications in HIV-1 infection]. / Complicaciones renales de la infección por VIH-1.

Renal involvement in AIDS may be specific or unspecific. Unspecific lesions, the most common, are usually an acute tubular necrosis produced by hemodynamic, infectious or electrolytic alterations that lead to an acute renal failure or drug nephrotoxicity. Specific lesions are segmental and focal hyalinosis, immune complex glomerulonephritis and thrombotic microangiopathy. Focal and segmental hyalinosis is observed almost exclusively in black people and produces a rapidly progressive renal failure. Lesions are a consequence of HIV stimulation of TGF beta in mesangial cells. Immune complex glomerulonephritis, formed by HIV antigens and anti HIV antibodies, is observed in white and black people. The glomerular lesion in this condition is less severe than in the former. Thrombotic microangiopathy could be a consequence of a pathogenic effect of the virus over glomerular capillaries and arterioles. It is clinically expressed as a hemolytic uremic syndrome. This paper reports briefly the renal pathological study of 46 patients infected with HIV-1, seen at the Nephrology Service of the Bichat Hospital in Paris.

[Involvement of the renal interstitium in systemic diseases (I)]. / Les atteintes de l'interstitium rénal au cours des maladies systémiques (I).

Interstitial lesions which are frequent in systemic diseases such as systemic lupus erythematosus, Sjögren's syndrome, sarcoidosis and Dobrin's syndrome (acute interstitial nephritis with uveitis) are described as well as their clinical expression. The immune reactions which are recognized to be responsible for these lesions are discussed in respect to each of these diseases.

Mesangial IgA deposits in two patients with AIDS-related complex.

Two patients with AIDS-related complex who presented with renal failure and microscopic hematuria were found to have mesangial deposits of IgA at renal biopsy. Though such glomerular deposits have not yet been reported in patients with HIV infection, their occurrence is most likely not coincidental. Indeed, there are striking similar abnormalities in patients with primary IgA nephropathy and in those infected with HIV. A careful screening for microscopic hematuria may lead to disclose further cases of mesangial IgA deposits in patients with HIV infection.

Hantavirus-related acute interstitial nephritis in western Europe. Expansion of a world-wide zoonosis.

We report the clinical, biological and serological characteristics of 76 cases of Hantavirus-induced acute interstitial nephritis diagnosed in Belgium and France between 1977 and 1986. The disease is characterized by a fever of sudden onset promptly accompanied by pain in the loin or abdomen, nausea and vomiting, myalgias and occasionally with acute myopia and conjunctival injection. Within a week acute renal failure develops, necessitating haemo- or peritoneal dialysis in up to 10 per cent of patients. Transient proteinuria, microscopic haematuria and leukocyturia are observed simultaneously. Thrombocytopenia and mild elevations of hepatic enzymes, LDH and CPK, as well as biological signs of acute inflammatory reaction are observed, lasting for a few days. Spontaneous complete recovery is the rule. This picture is virtually identical with that of nephropathia epidemica, a Hantavirus nephropathy observed in northern Europe. This conclusion is supported by the observation of elevated antibody titres against the Puumala virus, the agent of nephropathia epidemica. This rodent-borne infection is markedly milder than that caused by other Hantaviruses such as the Hantaan or the Seoul virus in Asia. Acute interstitial disease due to Hantavirus should be included in the differential diagnosis of febrile acute renal failure.