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A Cornelis

Publications and source records attributed to A Cornelis.

At least 19 recordsLinked to original sources
PubMed1997

Lesions of 13q may occur independently of deletion of 16q in spindle cell/pleomorphic lipomas.

AIMS: Very recent multidisciplinary investigations have allowed for the definition among lipomas of a clinical and histological subtype called spindle cell and/or pleomorphic lipoma, possibly associated with partial monosomy 16 and anomalies of chromosome 13. In order to get nearer to the underlying critical molecular changes further multidisciplinary pathological and genetic research is indicated, to identify which chromosome(s) anomalies are crucial in the development of these tumours. METHODS AND RESULTS: In an ongoing multidisciplinary study of lipomatous tumours, including clinical findings, morphology, histochemistry and cytogenetics, two instances were found of spindle cell lipoma with clonal chromosome changes. In both cases chromosome 13 was involved, whereas only one showed a partial monosomy 16. CONCLUSIONS: Partial monosomy 16 is a characteristic lesion in spindle cell lipoma, usually associated with anomalies of chromosome 13. The present report confirming a previous single observation indicates, however, that lesions of 13 may occur independently from lesions of 16, suggesting different underlying molecular lesions in these otherwise very similar lipomas.

Chromosome Deletion↗
PubMed1993

alpha-Amylase, a flour additive: an important cause of protein contact dermatitis in bakers.

BACKGROUND: alpha-Amylase, an enzyme commonly used in flour additives, has been reported to be an important cause of rhinitis and asthma in bakers. OBJECTIVE: Our purpose was to determine whether this enzyme could also cause dermatitis. We tested it routinely in bakers with hand eczema. METHODS: Patch tests were administered with the International Contact Dermatitis Research Group standard series and a bakery series and scratch-chamber or prick tests were performed with the bakers' own material and with alpha-amylase powder. RESULTS: Of 32 bakers tested, seven had an immediate wheal-and-flare reaction and two also had a delayed eczematous reaction. High dilutions of the alpha-amylase powder still gave strong reactions. CONCLUSION: alpha-Amylase is an important cause of skin reactions in bakers and should be tested routinely if a contact allergy is suspected.

Adult↗
PubMed1991

Different patterns of pulmonary sequelae after hyaline membrane disease: heterogeneity of bronchopulmonary dysplasia? A clinicopathologic study.

In an autopsy study of 37 infants who suffered from hyaline membrane disease (HMD), two distinct patterns of pulmonary lesions could be defined. One pattern, characterized by marked interstitial fibrosis in the absence of airway abnormalities, was labelled 'interstitial-type' histology. A second type, labelled 'bronchiolar-type' histology, showed marked airway lesions and alveolar emphysema. Nine patients of each type were analysed. Nineteen other patients had a 'mixed-type' histology and were not further studied. Retrospectively, the clinical and radiological characteristics of both series were analysed. No differences in birth weight, gestational age and initial radiological HMD grade could be demonstrated. The pulmonary function of the bronchiolar-type patients however was significantly worse at the onset, and these infants needed more oxygen and ventilatory support during the first 10 days of life. They all died from respiratory failure whereas 4 patients from the interstitial group had non-pulmonary fatalities. In the bronchiolar group chest X-rays showed atelectasis and pulmonary interstitial emphysema in the early stages, and hyperinflation with bullae and irregular streaky densities in the later. Patients in the interstitial group had no or minor emphysema with more homogeneously spread densities over both lungs. We conclude that both types of evolution represent two extremes of the bronchopulmonary dysplasia spectrum.

Bronchopulmonary Dysplasia↗
PubMed1990

Pathogenesis of the lethal multiple pterygium syndrome.

We present autopsy studies in 4 unrelated fetuses with the lethal multiple pterygium syndrome (LMPS) with special emphasis on the neuromuscular system. The data suggest that LMPS combines the manifestations of a jugular lymphatic obstruction sequence with those of an early severe fetal akinesia sequence. The jugular lymphatic obstruction sequence with resultant edema and cystic hygroma colli causes fetal lethality usually in the second trimester of pregnancy. Generalized amyoplasia appears to be an important mechanism in the pathogenesis of fetal akinesia as part of LMPS and is not associated with dysgenesis or degeneration of the central nervous system (CNS) but is apparently the result of an early fetal muscular "dystrophy." We propose a genetically determined insult affecting the early embryonic development of both lymph vessels and muscles as the basic defect in LMPS. Placental structure, studied in all 4 cases, demonstrated that triploidy-like placental lesions are specific to LMPS. The present findings suggest that LMPS may be a less heterogeneous entity than previously proposed.

Abnormalities, Multiple↗
PubMed1989

Heterogeneity of catalase staining in human hepatocellular peroxisomes.

Hepatocellular peroxisomes stained for catalase activity have different electron densities. When measured by scanning transmission electron microscopy, density is inversely linear to diameter. We investigated whether this phenomenon is the result of a staining artifact that reflects more efficient diffusion of substrate into smaller peroxisomes (higher surface-to-volume ratio), or of differences in endogenous enzymatic activity. Measurements of optical density show that the amount of reaction product is proportional to the diaminobenzidine concentration in the medium; this is not the case for H2O2. Modifying the concentration of both substrates does not alter the heterogeneous staining pattern. Heterogeneity persists when the reaction is slowed by inhibitors or when diffusion takes place before the reaction, and in preparations that have not been subjected to cytochemical staining. These data show that catalase activity is different in individual peroxisomes and that the staining differences are not a consequence of variations in substrate diffusion. Some implications of this conclusion are discussed.

3,3'-Diaminobenzidine↗
PubMed1989

Fully automated measurements by light microscopy of tissue sections using a cellular array computer.

Software was developed for the acquisition, segmentation and analysis of microscopic OD-images on a VICOM digital image processor, extended with a VISIOMORPH morphoprocessor board. The delineation algorithms for peroxisomes, lysosomes, and nuclei in liver, kidney, and adrenal gland sections start by thresholding the difference between the original image and a low pass filtered version. The resulting binary mask is then processed by morphological operations in order to produce an object overlay. The efficiency of the programs is evaluated by comparing delineated objects at different OD-levels, created by varying the stain or by multiplying the original pixel values with constant factors. Manual delineation on some images is also used as a reference. More complex algorithms are used for the delineation of muscle fibres in ATP-ase-stained sections and immunocytochemically labelled cells in monolayer preparations. Muscle images from parallel sections with different stainings are matched with a coordinate transform, enabling the transfer of the object mask from a single delineated image to the unprocessed images and thus obtain all necessary information for fibre classification. After segmentation, the OD-images and their object overlays are fed into a data extraction program, measuring for each delineated object user-selected features. Data are sent to a VAX for statistical interpretation.

Adrenal Cortex↗
PubMed1988

Automated measurement of kidney lysosomes by light microscopy. Influence of cyclosporine treatment.

After staining for acid phosphatase, video images were acquired from 1-micron sections of the kidneys of rats treated with cyclosporine. Automated segmentation of the lysosomes was followed by measurements of their area, number and optical density; tubular area was delineated manually. In addition to small lysosomes, representing more than 80% of the total number, all kidneys contained a second population of larger organelles. Cyclosporine treatment with 50 mg/kg/day for one week and with 25 mg/kg/day for three weeks, but not with 25 mg/kg/day for one week, induced a significant increase of lysosomal area, especially in the larger organelles (+200%). In a few animals, this was accompanied by a reduction in the number of lysosomes, suggesting a fusion of the organelles. Other parameters were not consistently modified by treatment. Cyclosporine treatment also elicited the appearance of fat droplets; however, lysosomes were not enlarged in tubular cells containing fat droplets.

Animals↗
PubMed1987

Infantile Refsum disease: an inherited peroxisomal disorder. Comparison with Zellweger syndrome and neonatal adrenoleukodystrophy.

Three patients affected by infantile Refsum disease are described with mental retardation, minor facial dysmorphia, chorioretinopathy, sensorineural hearing deficit, hepatomegaly, failure to thrive and hypocholesterolaemia. Initially, only an accumulation of phytanic acid was thought to be present. More recent findings showed a biochemical profile very similar to that found in classical Zellweger syndrome or neonatal adrenoleukodystrophy. Morphologically typical peroxisomes were absent in the liver. All three disorders are associated with multiple peroxisomal dysfunction. Because of these similarities pertinent clinical data of our three patients are compared with those of reported patients diagnosed as having infantile Refsum disease, neonatal adrenoleukodystrophy or Zellweger syndrome who survived for several years. Attention is drawn to the difference in severity of clinical features, ranging from infantile Refsum's disease to neonatal adrenoleukodystrophy and, finally, to Zellweger syndrome.

Adrenoleukodystrophy↗
PubMed1986

Hepatic peroxisomes are deficient in infantile refsum disease: a cytochemical study of 4 cases.

We examined liver biopsies from 4 patients with the infantile form of Refsum disease. No peroxisomes were visualized by light microscopy after cytochemical staining for catalase, a marker enzyme for this organelle. Absence of peroxisomes was confirmed by electron microscopy in 3 patients; in the 4th patient we observed organelles of peculiar size and structure and with minimal catalase activity. Light microscopy also showed birefringent macrophages containing P.A.S.-positive material; they were abundant in the 3 older children, and rare in the youngest (8 months). Peroxisomes and birefringent macrophages were absent in 2 patients with the cerebrohepatorenal syndrome of Zellweger. The simultaneous presence of these unique light microscopical characteristics may be of diagnostic value.

Birefringence↗
PubMed1985

Specific cytochemical stains in the image analysis of subcellular organelles.

This paper describes our work concerning densitometry and morphometry of subcellular structures in thin sections. The techniques of automatic image analysis were applied to light and electron microscopic observations of enzymatically stained lysosomes, renal brush borders and mitochondria (in human and rat kidney) and peroxisomes (in human liver). To obtain significant measurements of the enzymatic activity, specific staining techniques were developed and applied, including an improved staining of acid phosphatase for lysosomes. Optical densities were obtained by videodensitometry and electron densities of peroxisomes were obtained by digitizing and processing scanning transmission electron microscopic images. In subsequent steps, delineations and parameter estimation are performed by software. Included was an examination of delineation techniques, which showed improved results from the use of a newly developed local boundary search algorithm. The combination of these techniques was used to study changes in peroxisome and lysosome compartment in liver and kidney, some results of which are also reported.

Acid Phosphatase↗
PubMed1984

Automated measurement of acid phosphatase reaction product in human kidneys treated with aminoglycoside antibiotics.

The acid phosphatase reaction product was measured by automated image analysis densitometry in histologic sections from 23 human kidney biopsies. Optical density was proportional to incubation time, section thickness and enzyme activity. After a four days' treatment with aminoglycoside antibiotics, optical density was increased and paralleled the lysosomal changes previously observed by electron microscopy.

Acid Phosphatase↗
PubMed1983

Peroxisomes (microbodies) in human liver: cytochemical and quantitative studies of 85 biopsies.

The number, intracellular distribution, and staining characteristics of human hepatocellular peroxisomes that had been made visible by cytochemical staining for catalase were evaluated in biopsies from 75 patients with hepatic, inflammatory, or malignant disease and ten normal individuals. Intensity of staining was found to be proportional to enzymatic activity by microspectrophotometry. Scanning transmission electron microscopy (STEM) image analysis demonstrated an inverse relationship between peroxisomal size and contrast. Peroxisomes were more abundant, and often concentrated in a perinuclear configuration in cholestatic and cirrhotic livers. Decreased peroxisomal staining was common in cholestasis, cirrhosis, hepatitis, and in almost all patients with malignancies, both with and without hepatic metastases.

Biopsy↗
PubMed1981

Synthesis of 16 alpha-3H androgen and estrogen substrates for 16 alpha-hydroxylase.

The synthesis of 16 alpha-3H androgens and estrogens is described. 1-(3H)-Acetic acid in the presence of zinc dust reacts with 16 alpha-bromo-17-ketosteroids to produce 16 alpha-3H-17-ketosteroids. This chemical reaction was used to prepare 16 alpha-3H-dehydroepiandrosterone (I) and 16 alpha-3H-estrone acetate (XI) from 16 alpha-bromo-dehydroepiandrosterone (X) and from 16 alpha-bromo-estrone acetate (XII), respectively. Using appropriate microbiological techniques, it was possible to convert these radiolabelled substrates into 16 alpha-3H-androstenedione (II) and 16 alpha-3H-estradiol-17 beta (VII). 16 alpha-3H-Estrone (VI) was obtained by the chemical hydrolysis of 16 alpha-3H-estrone acetate. The label distribution as determined by microbiological 16 alpha-hydroxylations indicated a specific labelling of 77% for androgens and 65% for estrogens in the 16 alpha position. These substrates can be used for measuring the 16 alpha hydroxylase activity, an important step in the biosynthesis of estriol (VIII) and estetrol (IX).

Androgens↗