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Biomedical subjects

M Praet

Publications and source records attributed to M Praet.

At least 73 records · Page 4Linked to original sources

Ultrastructural alterations in the sialic acid distribution in minimal change disease and membranous glomerulonephritis.

Kidney biopsy specimens from patients with minimal change disease and membranous glomerulonephritis were embedded in glycolmethacrylate and stained with phosphotungstic acid (PTA) at low pH. Biopsy specimens from patients without proteinuria served as a control. The PTA staining at low pH on glycolmethacrylate sections was used to study the changes in the sialic acid content of the lamina rara externa of the glomerular basement membrane. This method also gives a clear picture of the changes occurring at the epithelial cell coat and these alterations have implications on the distribution of the negative charges. In minimal change disease no alterations could be observed in the sialic acid content of the lamina rara externa. But the luminal epithelial cell coat showed obvious changes in conjunction with extensive foot process widening. In membranous glomerulonephritis with heavy deposits the staining of the lamina rara externa became almost completely negative and the foot process architecture was strongly affected. Obvious defects at the luminal epithelial cell coat, as observed in minimal change disease, were also found regularly. The alterations at the epithelial cell coat are tentatively related to the selective proteinuria reported in minimal change disease. In addition the non-selective proteinuria observed in non-minimal glomerulopathies, may find its origin in the absence of sialic acid molecules from the lamina rara externa.

Basement Membrane↗

Right ventricular endomyocardial biopsy: clinicopathologic correlates in 64 consecutive patients.

Endomyocardial biopsy is a safe, reliable, and reproducible technique to confirm or establish the diagnosis of the pathology that affects cardiac function in conditions previously classified as cardiomyopathies of unknown cause. The first 64 consecutive patients to undergo endomyocardial biopsy were reviewed to determine its utility in various clinical settings. Furthermore a review of literature relating to endomyocardial biopsy is presented. On the basis of these findings, we conclude that endomyocardial biopsy is indicated in the clinical setting of dilated cardiomyopathy, for evaluating underlying myocarditis. In patients with dysrhythmias or clinical myocarditis, endomyocardial biopsy may disclose myocarditis or changes consistent with congestive cardiomyopathy. In patients with systemic disease endomyocardial biopsy is instructive to prove or to exclude myocardial involvement. In patients with angina-like chest pain but with normal coronary angiograms or exercise tests, endomyocardial biopsy may prove underlying heart disease.

Biopsy↗

In vivo and in vitro modifications of the mitochondrial membrane induced by 4' Epi-adriamycin.

Mice received 4' Epi-adriamycin (4' Epi-ADM) i.p. in increasing doses. After 48 hours, hearts were removed and mitochondria were isolated. 4' Epi-ADM had no effect on the enzymatic activities of complexes I-III and complex IV of the mitochondrial respiratory chain; no modification of the mitochondrial membrane viscosity was observed and only a slight membrane lipid peroxidation was measured. On the contrary, in vitro studies showed a 4' Epi-ADM dependent enzymatic inactivation of complex I-III and IV, correlated with a mitochondrial membrane rigidification and an enhanced lipid peroxidation rate.

Animals↗

Acute tubulo-interstitial nephritis and uveitis syndrome (TINU syndrome).

Acute renal failure due to tubulo-interstitial nephritis developed in a 15-year-old girl. The disease was accompanied by uveitis and an inflammatory syndrome, consisting of a markedly increased erythrocyte sedimentation rate and high serum gamma globulin levels. The nephropathy as well as the inflammatory syndrome subsided spontaneously. A topical antiphlogistic treatment healed the ocular disease, which has not relapsed so far. The association of acute tubulo-interstitial nephritis and acute uveitis observed in several patients has led to the identification of a specific syndrome with a very particular symptomatology and course, the so-called TINU syndrome, the interest of which resides in the predictability of the complete reversibility of the nephropathy either spontaneously or after steroid treatment, contrasting with the marked tendency towards relapse of the uveitis. The demonstration of circulating immune complexes in the serum during the acute phase of the illness, as in our patient, further points to the involvement of immune processes in the syndrome, but the origin and pathogenesis remain as yet unknown.

Acute Disease↗

Captopril: a protective agent in renal warm ischemia in rats.

Captopril, an angiotensin-converting enzyme inhibitor, was used as a protective agent before and after 90 min of renal warm ischemia in rats. At a dose of 1 mg/kg, it was able to lower the postoperative serum creatinine values significantly (from 6.3 to 2.5 mg% on the 2nd postoperative day) in unilaterally nephrectomized animals. Increasing the dose to 4 and 8 mg/kg or combining captopril with hypertonic mannitol (10 ml/kg of a 15% aqueous solution) did not improve these figures significantly. The same magnitude of protection was obtained when captopril was given either before or just after the ischemia. In terms of mortality the differences among unprotected and protected groups were very important: only 6 of 24 unprotected animals survived the 5th postoperative day while 42 of 44 protected animals survived.

Animals↗

Cytochemical analysis of the chromatin of liver cell nuclei and nuclei of oval cells by means of the Feulgen hydrolysis curve in rats treated by thioacetamide.

The present study is an analysis of the Feulgen hydrolysis characteristics in nuclei of liver cells and oval cells in rats treated by thioacetamide (TAA) and of liver cells in control rats. The curves show a double-peaked pattern. A slower hydrolysis is noted in the first peak after TAA treatment. This suggests an alteration of the acid-labile part of the chromatin. The curve obtained in the oval cells is different from the one in the liver cells. The implications of these differences are discussed with respect to development of cholangiocarcinomas.

Acetamides↗

Damages of the mitochondrial membrane in Adriamycin treated mice.

OF1 Swiss male and female mice received adriamycin (ADM) i.p. in increasing doses. Animals were killed after 2 or 4 days. Hearts were removed and mitochondria were isolated. ADM induced an inactivation of the respiratory enzymes closely related to an increase of the mitochondrial membrane viscosity and of the lipid peroxidation. Two ADM derivatives studied similarly did not produce these effects.

Animals↗

Diquat intoxication: report of two cases and review of the literature.

Animal experiments have suggested that diquat is less toxic than the more widely used paraquat. In this paper, nine previously reported cases of diquat intoxication are reviewed, together with the description of our personal observations in two additional patients. These two patients, like four other patients described in the literature, died from complications involving the gastrointestinal tract, brain and kidneys. Thus, diquat intoxication is apparently not as innocent as was originally thought. In this paper, special attention has been given to the major clinical differences between diquat and paraquat intoxication. In contrast with the latter, severe diquat intoxication induces gastrointestinal fluid sequestration and is associated with cerebral hemorrhagic lesions and a higher incidence of severe acute renal failure. Despite an asymptomatic clinical interval of up to 48 hours after ingestion, hemoperfusion should be started as soon as possible to prevent toxic levels of diquat in tissue.

Acute Kidney Injury↗

Focal nodular hyperplasia of the liver: detection and characterization with plain and dynamic-enhanced MRI.

BACKGROUND: We compared nonenhanced and dynamic gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) appearances of hepatic focal nodular hyperplasia (FNH) as depicted with breath-hold MR sequences and assessed the detectability of the individual MR sequences used. METHODS: We retrospectively reviewed 48 consecutive patients with FNH. All patients underwent nonenhanced (T1 fast low-angle shot [FLASH] and T2 half-Fourier acquisition [HASTE]) and dynamic Gd-enhanced (T1 FLASH) MRI between December 1997 and March 2000. Individual MR sequences were analyzed separately for number of lesions, signal intensity features, dynamic enhancement pattern, and the presence and enhancement profile of a central scar. Ninety-five percent confidence intervals of absolute discrepancy were calculated to define differences in lesion detection. RESULTS: Seventy-seven lesions were found in 48 patients. Nonenhanced FLASH imaging depicted 59 (76.6%) lesions in 45 patients. HASTE images showed 55 (71.4%) lesions in 44 patients. On T1- and T2-weighted images, lesions appeared predominantly hypointense (69.5%) and hyperintense (72.7%), respectively. Arterial and portal venous dominant phase Gd-enhanced MRI demonstrated all 77 lesions (100%), most of which showed hypervascular (94.8%), homogeneous (97.4%), and incomplete (except the central scar: 58.4%) enhancement in the arterial phase. Portal venous phase images showed lesion isointensity (50.6%) or moderate hyperintensity (46.8%) with complete enhancement (central scar: 94.8%). A central scar was detected on nonenhanced T1-weighted images (hypointense: 100%), T2-weighted images (hyperintense: 100%), arterial phase (hypointense: 59.7%) and portal venous phase (hyperintense: 71.4%) Gd-enhanced images in 78%, 69.1%, 77.9%, and 75.3% of tumors, respectively. CONCLUSION: Arterial and portal venous phase Gd-enhanced T1-weighted sequences are superior to nonenhanced images in the detection of FNH. Typical MRI appearances include hypointensity on T1-weighted and hyperintensity on nonenhanced T2-weighted images. Most commonly, FNH shows a homogeneous (without scar) and strong enhancement during the arterial phase, with lesion isointensity or slight hyperintensity during the portal venous phase.

Adult↗

Intratumoral steatosis in focal nodular hyperplasia coinciding with diffuse hepatic steatosis: CT and MRI findings with histologic correlation.

Focal nodular hyperplasia (FNH) is a benign tumorlike condition that is thought to be a hyperplastic response to increased blood flow in an arterial malformation rather than a true neoplasm. Radiologically, FNH usually shows typical findings on unenhanced and enhanced computed tomography (CT) and magnetic resonance images (MRI), with atypical features being the exception rather than the rule. We report an unusual case of FNH with extensive fatty infiltration of the lesion illustrated on CT and MRI and proven by histopathology.

Biopsy↗