Biomedical subjects

D De Craemer

Publications and source records attributed to D De Craemer.

34 records · Page 2Linked to original sources

PubMed1993

Catalase-negative peroxisomes in human embryonic liver.

Hepatic peroxisomes in human embryos with a menstrual age of 6 and 7 weeks have been examined via catalase cytochemistry. In the younger sample, the organelles show no catalase activity, their matrix being pale and coarsely reticular. In the 7-week specimen, the peroxisome population consists of catalase-positive and catalase-negative organelles. The latter have a morphology identical to that of the 6-week sample and represent 66% of the population. The positive organelles show a pronounced staining heterogeneity. Together with the simultaneous presence of negative organelles, this might reflect the onset of catalase import into the peroxisomes during this period. Catalase heterogeneity excludes a continuous exchange of matrix contents; moreover, interconnections between peroxisomes have not been observed, and no cluster formation occurs. The data therefore also suggest that catalase is imported into individual, preexisting organelles in embryonic liver. The three peroxisomal beta-oxidation enzymes become detectable by immunocytochemistry only later during development. Morphological indications for a rapidly dividing population, such as elongated and/or tailed organelles, have not been observed. Morphometry has revealed that, in these early stages, the organelles are significantly smaller than the peroxisomes of fetal and adult human liver.

Catalase↗

PubMed1993

Peroxisomes in liver, kidney and duodenum of nude mice bearing xenografts of human pancreatic adenocarcinomas.

In the liver, kidney and duodenum of nude mice with xenografts of two human pancreatic adenocarcinomas differing in growth rate, catalase activity was assayed and peroxisomes were studied using catalase cytochemistry and light and electron microscopy. Hepatic and duodenal catalase activity were significantly decreased in tumour-bearing mice. Renal catalase activity was unchanged. At light microscopic level, a decrease in peroxisomal staining was evident in all duodenums and most livers of tumour-bearing mice. Only minor changes were observed in the kidneys. Ultrastructural morphometry of the hepatocellular peroxisomes revealed a decrease in size, volume density and surface density only in mice with fast-growing xenografts. These observations indicate that the two pancreatic adenocarcinomas exerted a different effect on the hepatic peroxisomes, and that catalase activity and peroxisomes in liver and duodenum are more affected than in kidney.

Adenocarcinoma↗

PubMed1993

Peroxisomes in cirrhosis of the human liver: a cytochemical, ultrastructural and quantitative study.

Hepatocellular peroxisomes in 32 patients with cirrhosis were studied by means of catalase cytochemical and morphometric analysis. Seven normal human livers were used as controls. The severity of the cirrhosis was determined with the Child-Turcotte criteria. Under the light microscope, a decrease in catalase staining was observed in 12 livers. Staining showed a weak inverse correlation with severity of the cirrhotic process. Peroxisomes revealed a perinuclear configuration in 24 patients. Morphometric analysis of peroxisomes was performed on 14 cirrhotic livers and revealed a near doubling of the number of organelles, with a compensatory decrease in mean peroxisomal diameter: no appreciable change in total volume of the peroxisome compartment was found. Cytoplasmic invaginations, protrusions and gastruloid cisternae were sparse. Apparently, peroxisomal proliferation in liver cells appeared early in the cirrhotic process. In all 10 livers with a perinuclear configuration of the peroxisomes that were processed for electron microscopy, a morphometrically confirmed increase in the number of peroxisomes was observed. Peroxisomes frequently showed transparent matrical spots and angular profiles. In two patients nucleoid-containing peroxisomes were observed. Although variation between individual patients was high, peroxisomal changes were observed in each cirrhotic liver. No relationship between morphological or morphometric alterations in peroxisomal compartment on one side and the severity of the disease or the type of cirrhotic nodules on the other side was observed.

Adult↗

PubMed1991

Hepatocellular peroxisomes in human alcoholic and drug-induced hepatitis: a quantitative study.

The peroxisomes in the liver of four patients with alcoholic hepatitis and in six patients with drug-induced hepatitis are compared to eight control livers by catalase cytochemistry and morphometry. A decrease of catalase activity is observed in alcoholic, amitriptyline, aprindine, clomipramine and methiomazole hepatitis. Peroxisomes with a heterogeneous distribution of the catalase reaction product are found in most hepatitis livers. The number of organelles is increased 1.5 to 4.2 times in alcoholic, aprindine, methimazole and phenytoin hepatitis livers. In the last case, peroxisomes are also smaller. Changes in shape are seen in all hepatitis livers; they include invaginations, tails, funnel-like constrictions and gastruloid cisternae. In aprindine, phenytoin, methimazole and two alcoholic hepatitis livers, surface density exceeds the upper control value. These data indicate a loss of catalase activity in most hepatitis livers but also peroxisomal proliferation and shape modifications. It has been proposed that the latter changes are favorable for metabolic activity.

Biopsy↗

PubMed1991

Peroxisomal localization of the immunoreactive beta-oxidation enzymes in a neonate with a beta-oxidation defect. Pathological observations in liver, adrenal cortex and kidney.

A boy born to healthy, unrelated parents, presented at birth with hypotonia and seizures. Very long chain fatty acids in the plasma were strongly elevated; bile acid intermediates and plasmalogen biosynthesis were normal. Acyl-CoA oxidase activity was normal. The patient died at the age of 3 months. The cerebellum and medulla oblongata showed neuronal migration defects. The specific biochemical basis for the impaired peroxisomal beta-oxidation has not been found. The three immunoreactive peroxisomal beta-oxidation enzymes and catalase were localized in the hepatocellular peroxisomes. Aberrant features of the peroxisomes included: a subpopulation of organelles larger than 1 micron, an amorphous nucleoid in many organelles, and invaginations of the peroxisomal membrane into the matrix. Peroxisomes in the proximal renal tubules also contained the three immunoreactive beta-oxidation enzymes. Regularly spaced trilamellar inclusions were seen in hepatic macrophages; they were much more abundant in adrenocortical macrophages. The inclusions were birefringent and resistant to acetone extraction. Distinct hepatic fibrosis had developed over a period of 2.5 months. We speculate that the impaired beta-oxidation is due to a defect at the level of the peroxisomal carnitine octanoyl or -acetyl transferase, responsible for the export of beta-oxidation products.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1991

Very large peroxisomes in distinct peroxisomal disorders (rhizomelic chondrodysplasia punctata and acyl-CoA oxidase deficiency): novel data.

We report very large hepatic peroxisomes (d-circle greater than 1 micron) in a patient with rhizomelic chondrodysplasia punctata and a patient with acyl-CoA oxidase deficiency. The effects of peroxisomal enlargement on the enzymatic activity are discussed. As increase in peroxisomal size is also reported in at least 12 other patients with peroxisomal disorders, we propose a relationship between the enlargement of the organelles and their functional deficiency.

Acyl-CoA Oxidase↗

PubMed1991

Liver pathology and immunocytochemistry in congenital peroxisomal diseases: a review.

Diagnostic and pathogenetic investigations of peroxisomal disorders should include the study of the macroscopic and microscopic pathology of the liver, in addition to careful clinical observations, skeletal X-ray and brain CT scan, assays of very long-chain fatty acids and bile acid intermediates, and selected enzyme activities. This review of the literature also contains novel observations about the following syndromes: cerebro-hepato-renal (Zellweger) syndrome, X-linked and neonatal adrenoleukodystrophies (ALD, NALD), NALD-like syndromes, infantile phytanic acid storage, classical Refsum disease, rhizomelic and other forms of chondrodysplasia punctata (XD, XR, AR), hyperpipecolic acidaemia, primary hyperoxaluria I, pseudo-Zellweger and Zellweger-like syndromes, and single enzyme deficiencies. Microscopic data include catalase staining and morphometry of peroxisomes, immunolocalization of beta-oxidation enzymes, detection of trilamellar, polarizing inclusions in PAS-positive macrophages, fibrosis and iron storage. Peroxisomal enlargement appears to be related to functional deficit in beta-oxidation disorders as well as in rhizomelic chondrodysplasia punctata. Because normal peroxisomal localization of active beta-oxidation enzymes can accompany a C26 beta-oxidation deficit, other mechanisms such as impaired transport of metabolites should be investigated. 'Ghost'-like organelles are shown in the liver of an infantile Refsum patient and in an NALD-like case; immuno-gold labelling of membrane proteins did not reveal ghosts in Zellweger livers.

Humans↗

PubMed1991

Different types of peroxisomes in human duodenal epithelium.

Peroxisomes are ubiquitous organelles containing enzyme sequences for beta oxidation of fatty acids, synthesis of bile acids, and ether phospholipids. In the inherited peroxisomal diseases one or more enzymes are deficient in hepatic, renal, and fibroblast peroxisomes. We have examined peroxisomes by light and electron microscopy in 29 duodenal biopsy specimens (21 with normal mucosa) after staining for catalase activity, a marker enzyme. Peroxisomes were most numerous in the apices of the nucleus and at the villus base. Two types were distinguished: rounded to oval forms with a median lesser diameter of 0.23-0.31 microns, and tubular, vermiform organelles 0.1 microns thick and up to 3 microns long. Both types coexist in most patients. Tilting of sections and examination of semithin sections at 120 kV did not show connections between individual organelles. By morphometry, volume density was at least 0.45-0.62% of cellular volume, compared to 1.05% in human liver. In contrast, in four out of five individuals surface density of the peroxisomal membrane was 1.4-2.3 times higher than in control livers; this is expected to favour the exchange of metabolites. We suggest that intestinal peroxisomes contribute substantially to the breakdown of very long chain fatty acids.

Adult↗

PubMed1990

Post-mortem visualization of peroxisomes in rat and in human liver.

This paper describes spontaneous post-mortem changes of peroxisomal staining in normal liver and kidney of rats and in human autopsy liver. At room temperature, regional staining loss is observed at 18 h after death in rat kidney, at 24 h in human liver and at 48 h in rat liver. Preservation at 4 degrees C delays this phenomenon. In human liver, the peroxisomal volume density is decreased at both temperatures at 48 h. After freezing of fresh tissue in dry ice, peroxisomal staining is decreased homogeneously. Under the electron microscope, peroxisomal alterations suggest a loss of catalase activity. These changes do not necessarily preclude the study of peroxisomal features since, even after 48 h at room temperature, peroxisomes are still well stained in the less affected regions. Catalase and three beta-oxidation enzymes, namely acyl-CoA oxidase, bifunctional protein (with enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase) and 3-oxoacyl-CoA thiolase, could be visualized immunocytochemically in human autopsy livers up to 48 h after death. However, the study of certain peroxisomal features such a catalase activity and peroxisomal distribution, may be hampered as the post-mortem period is prolonged.

Animals↗

PubMed1990

Immunocytochemical detection of peroxisomal beta-oxidation enzymes in cryostat and paraffin sections of human post mortem liver.

The immunocytochemical visualization of the peroxisomal beta-oxidation enzymes was investigated in three human post mortem liver samples. Acyl-CoA oxidase, bifunctional protein and 3-oxoacyl-CoA thiolase remained immunocytochemically detectable 30, 55 and 72 h after death. Peroxisomes in the parenchymal cells were clearly visualized for light microscopy (paraffin and cryostat sections), using protein A-gold in combination with silver enhancement. In two samples catalase activity became very weak, but catalase antigenicity was well preserved. The findings prove the diagnostic value of post mortem samples, even after extreme conditions of tissue conservation. The technique of immunocytochemical staining for the peroxisomal beta-oxidation enzymes on unmounted cryostat sections has not been reported previously. This method allows a quick diagnosis of biopsies from patients suspected of peroxisomal disorders.

Catalase↗

PubMed1990

Alterations of hepatocellular peroxisomes in viral hepatitis in the mouse.

In addition to being found in peroxisomal diseases, peroxisomal alterations are also seen in viral hepatitis, though quantitative data are lacking. Experiments were performed on BALB/c mice. These mice were infected with Mouse Hepatitis Virus type 3 or were starved. The peroxisomes were cytochemically stained for catalase. Light microscopic, ultrastructural and morphometric analysis were performed. Several peroxisomal changes were observed 24 h after infection, and these changes became more pronounced after 40 h. There was a decrease in catalase activity, which was more pronounced in some regions, in some cells and in individual organelles; and there was also the onset of a progressive decrease in the number of organelles. It is believed that peroxisomes disappear by lysis. Proliferation probably occurs simultaneously up to 40 h after infection. At 48 h, necrotic foci are found to have swollen peroxisomes, and thus destruction is enhanced. Although peroxisomes seem to be sensitive markers of hepatic injury, they show a heterogeneous reaction pattern. Our results are discussed in relation to human viral hepatitis.

Animals↗

PubMedDate not supplied

Antioxidant enzyme gene expression in rats with remnant kidney induced chronic renal failure.

Reactive oxygen intermediates play a role in chronic renal injury and glomerulosclerosis. We investigate changes in renal cortex antioxidant enzyme gene expression in the rat remnant-kidney model of chronic renal failure and compare the new data to enzyme activities published earlier. Antioxidant enzyme gene expression is evaluated by Northern blot analysis of cortex mRNA, using cDNA probes for catalase, copper/zinc-containing superoxide dismutase, and glutathione peroxidase. Catalase gene expression decreases during development of renal failure; this decrease is accompanied by decreased catalase activity during the glomerulosclerosis phase of the remnant-kidney model. Copper/zinc superoxide dismutase and glutathione peroxidase gene expression remain at a normal level during progression of the model, whereas their activities show a temporary decrease in the early remnant kidney. In the remnant-kidney model, catalase seems to be more vulnerable to reactive oxygen intermediates than superoxide dismutase and glutathione peroxidase. Our results show that antioxidant enzyme activity and gene expression do not change in the same direction at all times during disease development and that all antioxidant enzymes do not respond in the same way.

Actins↗

PubMedDate not supplied

Angiotensin II administration causes enhanced expression of glomerulosclerosis-related markers and decreased renal antioxidant enzyme activities in rats.

Angiotensin II administration to rats during 6 weeks causes decreased activity of catalase and glutathione peroxidase in renal cortex. Rats show mild hypertension, subclinical signs of renal injury, increased glomerular expression of desmin, glomerular and interstitial expression of alpha-smooth muscle actin and an increased number of ED-1-positive cells in glomeruli. An inverse correlation exists between catalase activity and glomerular alpha-smooth muscle actin expression and between glutathione peroxidase activity and glomerular desmin expression. The decrease of antioxidant enzyme activity, early after angiotensin II administration, might be an important initiating factor in the complex process leading eventually to renal sclerosis by reduction of reactive oxygen intermediate breakdown. The significant relationship between markers of sclerosis and some antioxidant enzyme activities suggests either a causative link or a common triggering factor.

Actins↗

PubMedDate not supplied

Cytoplasmic catalase and ghostlike peroxisomes in the liver from a child with atypical chondrodysplasia punctata.

In the liver biopsy from an 8.5-year-old girl with the biochemical characteristics of rhizomelic chondrodysplasia punctata (RCDP), but with normal limbs, normal catalase-containing peroxisomes were absent. Light microscopy after diaminobenzidine staining for catalase activity (the peroxisomal marker enzyme) and immunostaining against catalase protein indicated a cytosolic localization of the enzyme. By electron microscopy, rare and extremely large, irregularly shaped vesicles were found in the parenchymal cells. The three peroxisomal beta-oxidation enzymes (acyl-CoA oxidase, bi(tri)functional enzyme, and 3-ketoacyl-CoA thiolase) and alanine-glyoxylate aminotransferase were immunolocalized in these organelles. However, a weak to negative label was obtained after staining against catalase. Diaminobenzidine staining demonstrated a minimal catalase reaction product in some vesicles only. Morphometry revealed a corrected mean d-circle of 1.44 microns and a maximum d-circle of 2.767 microns (controls: 0.635 microns and 1.027 microns, respectively). Numerical, volume, and surface densities were reduced to 3%, 41%, and 17% of control values, respectively. The large size, irregular shape, and rarity of the organelles are morphologic features of peroxisomal "ghosts." It seems that in this patient, apart from the known peroxisomal defects in RCDP, catalase incorporation into the peroxisomes is impaired together with a normal proliferation (division) of the organelles. In the cultured skin fibroblasts from the patient, however, immuno-electron microscopy showed normal catalase-containing peroxisomes in apparently normal numbers.

Catalase↗

PubMedDate not supplied

Rapid effects of dietary fish oil on peroxisomes in mouse liver.

We investigated hepatic catalase activity, and morphologic and morphometric alterations of hepatocellular peroxisomes after catalase cytochemistry, in mice given a diet supplemented with 10% Beromegan, a commercial fish oil preparation, for up to three days. Fish oil is rich in docosahexaenoic acid (C22:6 (n-3)) and in eicosapentaenoic acid (20:5 (n-3)). Hepatic catalase activity showed a gradual increase in mice fed this diet, being significantly increased (136 +/- 10 UB/g liver) after three days when compared top controls (85 +/- 11 UB/g liver). Light microscopy indicated an increase in peroxisomal staining and peroxisomal proliferation. The latter observation was confirmed by ultrastructural morphometry: number, volume density and surface density of the peroxisomes were more than doubled after a three day diet containing fish oil. Peroxisomal size was not changed. These alterations are suggestive for an increased peroxisomal metabolism induced by a diet rich in poly-unsaturated fatty acids.

Animals↗

PubMedDate not supplied

An image analysis study of vastus lateralis muscle fibers in malignant hyperthermia susceptible patients.

We studied the correlation between the in vitro contracture test (IVCT) performed in malignant hyperthermia (MH) and the muscle fiber type composition in 29 human vastus lateralis (VL) biopsy samples (from 12 women and 17 men) using a semiautomated image analyzer. Relative number, lesser diameter, global area, and spatial distribution of the muscle fibers were measured. In these and in 26 additional VL muscle biopsy samples of patients with other myopathies, we compared our morphometric data with the observations made by the pathologist. Among the MH group, type 1 fibers were larger in both malignant hyperthermia susceptible (MHS) men and women reaching statistical significance only in the latter. The relative number and global area were unchanged. In MHS patients relative number and global area of type 2A fibers were smaller. No changes in the parameters of type 2B fibers were found. In a minority of sections (14%) clustering was observed. Sex-related alterations in type 2 fiber characteristics were found between MHS patients. However, our findings do not clearly point towards a syndrome-induced alteration of size, number, global area, or distribution of type 1, 2A, and 2B muscle fibers in VL of MH patients. By morphometric analysis, we found several additional biopsy samples that met the interpretation of "abnormal" size and number of muscle fibers in human malignant hyperthermia than were reported by the pathologist.

Adolescent↗