Biomedical subjects

N Roos

Publications and source records attributed to N Roos.

At least 109 records · Page 6Linked to original sources

PubMed1990

[Thoracic sarcoidosis].

Sarcoidosis is essentially a granulomatous disease of unknown etiology. The pathogenesis is assumed to consist in an abnormal immune reaction to a still unidentified antigen. The commonest manifestations of sarcoidosis are mediastinal and hilar lymphadenopathy and pulmonary infiltrates. The complex variety of clinical presentations of sarcoidosis means that the differential diagnosis has to include a wide range of entities. The clinical and radiological features of thoracic sarcoidosis are described, and the spectrum of relevant investigations is discussed. With respect to radiological diagnosis, computed tomography, with its higher sensitivity than other techniques, is of particular value for the precise determination of the morphological correlate of pulmonary and nodal changes and their functional relevance.

Diagnosis, Differential↗

PubMed1990

[Changes in the lungs in mucoviscidosis. Feasibility and advantages of different imaging techniques].

Pulmonary abnormalities in cystic fibrosis result from the obstruction of small bronchi by highly viscous mucus. Chronic obstructive lung disease and recurrent pulmonary infections result in a typical radiographic pattern later in the disease. Most patients can now be expected to survive into adulthood. The radiologist must make a careful comparison of serial films in order to detect complications early. By far the most important imaging modality is the conventional chest radiograph. CT is more sensitive for detection of structural abnormalities of the lung. Bronchography is a dangerous procedure and can lead to rapid deterioration of lung function. Lung scanning is a very sensitive method for demonstrating regional disturbances of ventilation and may reveal abnormalities earlier than conventional radiographs. In severe hemoptysis, selective bronchial arteriography with embolization of the bleeding vessel can be a life-saving procedure.

Angiography↗

PubMed1990

[Bronchoscopic diagnosis of therapy refractory pneumonia].

In 73 patients with pneumonia treated empirically with antibiotics or antimycotics, a bronchoscopy with bronchoalveolar lavage was performed in an attempt to identify the pathogens involved. Patients in whom it proved possible to detect a specific pathogen showed a lower mortality rate than did those in whom it was not possible to clarify the aetiology of the pneumonia (24 per cent and 34 per cent, respectively). In patients receiving empirical treatment over a long term, pneumonia persisted longer, and the mortality rate was higher, than in patients who were submitted to invasive examination early on.

Adolescent↗

PubMed1990

[Computerized tomography diagnosis of opportunistic lung mycoses].

In 11 patients with opportunistic pneumo-mycosis, computed tomography revealed a predominantly nodular infiltration pattern of the lungs, which revealed particular features that showed a dependence on the species of pathogen involved and the stage of the disease. Computed tomography of the chest proved to be superior to conventional chest films in the clarification of unclear fungal pneumonia in patients on immunosuppressive treatment.

Aspergillosis↗

PubMed1990

Endocytosis mediated by the mannose receptor in liver endothelial cells. An immunocytochemical study.

Immunocytochemical labeling of ultrathin cryosections from rat liver showed that mannose-terminated glycoproteins are removed rapidly from the blood stream mainly by the sinusoidal endothelial cells. The mannose-terminated glycoprotein ovalbumin was injected intravenously into rats 1 min, 6 min, and 24 min before perfusion fixation of the liver. Several minor and at least three major subcellular compartments were shown to be involved in the endocytic process. One minute after injection, ovalbumin was found at the cell surface, in coated pits, in coated vesicles, in tubular structures, and bound to the membrane of large early endosomes of which some showed a cisternal structure. After 6 min, ovalbumin was found in the lumen of large electron-lucent late endosomes and after 24 min in electron-dense structures, presumably lysosomes. The early endosomes have an ultrastructure which, together with the labeling pattern, indicates that this compartment has the same function as the CURL identified in parenchymal liver cells. The results are in accordance with recent biochemical findings indicating that ovalbumin endocytosed by endothelial cells is found sequentially in three different subcellular fractions depending on the time between injection and cooling for fractionation (G. M. Kindberg, T. Berg: Intracellular transport of endocytosed mannose terminated glycoproteins in rat liver endothelial cells. In: E. Wisse, D. L. Knook, K. Decker (eds.): Cells of the Hepatic Sinusoid. Vol. 2. pp. 120-124. Kupffer Cell Foundation. Rijswijk The Netherlands 1989).

Animals↗

PubMed1990

Internalization of retinol-binding protein in parenchymal and stellate cells of rat liver.

We have studied uptake of retinol-binding protein (RBP) by rat liver cells. First, we compared the in vivo uptake in different liver cells of 125I-labeled RBP with that of other well-known ligands. We found that the ligands studied were recognized differently by the various cell types in the liver, and that RBP was most efficiently taken up by parenchymal and stellate cells. We then studied the in vivo uptake of RBP in liver cells by immunocytochemistry at the electron microscopic level using ultrathin cryosections. Ten min after injection, RBP was localized to parenchymal cells and stellate cells. In these cells, RBP was detected on the cell surface and in vesicles near the cell surface. RBP was observed mainly in association with the membrane in these vesicles. Two hours after injection, RBP was localized not only on the cell surface and in vesicles close to the cell surface, but also in larger vesicles located deeper in the cytoplasm of these cells. RBP in larger vesicles was observed at a distance from the vesicular membrane. Finally, we compared the distribution of endocytosed RBP in liver parenchymal cells with that of asialo-orosomucoid, a ligand known to be internalized by receptor-mediated endocytosis. We detected both ligands on the cell surface and in small vesicles located close to the cell surface and in larger vesicles located deeper in the cytoplasm. Asialo-orosomucoid and RBP were seldom observed in the same small vesicles, but the larger vesicles contained both ligands. These data suggest that RBP is internalized in parenchymal and stellate cells of the liver by receptor-mediated endocytosis.

Animals↗

PubMed1989

[Image quality of various venous catheters in ultrasound under standardized conditions].

Seven different types of venous catheters were visualised under standardised conditions with a 5 mHz linear scanner for comparison of their respective imaging qualities. Under these conditions, all catheters were readily identifiable regardless of fabric and width. Any formation of loops or knots could also be visualised.

Catheterization, Central Venous↗

PubMed1989

[Vertebral body lesions as an interference factor in quantitative computed tomography of the lumbar spine. An analysis of 1116 standardized performed measurements].

The type, frequency and location of lumbar vertebral lesions that may interfere with quantitative computed tomographic (QCT) estimation of bone mineral content were analysed in 1166 cases. All examinations were carried out with a standard protocol on the second, third and fourth vertebral body. A total of 130 lesions were identified, the majority of which included degenerative sclerosis of L4 and compression fractures of L2. Evaluation of 28 QCTs with compression fracture in one vertebral body showed that an accurate BMC value was obtained with an interendplate distance of 13 mm or more.

Bone Density↗

PubMed1989

[CT studies of the lung in opportunistic infections].

Immunosuppressive patients are at high risk of opportunistic infections whose main site of manifestation is the lung. The prognosis depends largely on starting therapy in time. Thorax CT supplies an important contribution especially in diagnosis and monitoring of pneumomycoses, which are particularly relevant among the problem infections on account of their frequently lethal course: compared with conventional thorax imaging, CT detects infiltrates much earlier; in addition, it presents a characteristic course of pulmonary changes enabling at least in part some conclusions regarding the pathoanatomical substrate. The article reports on the prerequisites for an infection justified indication for thoracic CT, on its execution and on the findings as for example in pneumomycoses.

Aspergillosis↗

PubMed1989

[Mycetoma-like manifestations in invasive pulmonary aspergillosis].

Invasive pulmonary aspergillosis is characterized by radiological signs allowing a correct diagnosis, including differentiation from pulmonary candidiasis, when they are associated with appropriate clinical symptoms (neutropenia and fever persisting despite broad-spectrum antibiotics). In particular the formation of a pulmonary mycetoma in a previously normal lung is one of these signs. Unlike a simple fungus ball (the saprophytic form of aspergillosis), the rounded density of invasive pulmonary aspergillosis consists of sequestrum of devitalized lung tissue owing to blood vessel invasion by Aspergillus hyphae. This morphologic phenomenon is demonstrated in the present case report and is discussed together with the other roentgenological signs of the invasive aspergillosis.

Aspergillosis, Allergic Bronchopulmonary↗

PubMed1988

A possible site of calcium regulation in rat exocrine pancreas cells: an X-ray microanalytical study.

We analysed four subcellular compartments in rat exocrine pancreas cells, zymogen granules, cytoplasm surrounding the zymogen granules, mitochondria and cytoplasm in the basal part of the cells for sodium, magnesium, phosphorus, sulfur, chlorine, potassium and calcium content, using ultrathin frozen-dried cryosections. The highest concentrations of calcium were measured in the zymogen granules and the surrounding apical part of the cell containing Golgi apparatus, smooth endoplasmic reticulum and condensing vacuoles. Calcium concentrations in the basal part of the cells (mostly rough endoplasmic reticulum) were 60% lower than in the apical part of the cells. The lowest calcium concentrations were measured in mitochondria. The results suggest that other subcellular compartments than the rough endoplasmic reticulum and mitochondria might be involved in the intracellular Ca2+ regulation.

Animals↗

PubMed1987

Use of claims data systems to evaluate health care outcomes. Mortality and reoperation following prostatectomy.

Data maintained by medical insurance plans can be used to evaluate the incidence of death and nonfatal complications following medical care, to test hypotheses about the outcomes of care, and to identify hospitals with unusually high or low death rates. These uses are illustrated for prostatectomy, utilizing claims data from the Maine Medicare and Manitoba Health Services Commission files. The study shows important differences in death rates between individual hospitals and higher cumulative probability of reoperation following transurethral compared with open prostatectomy. The advantages of claims data are low cost, ease of patient follow-up over long periods, and the absence of reporting bias. The limitations are the adequacy of the data used to control for patient comorbidity and the lack of outcome information on functional status. The effective use of claims data for monitoring requires the active participation of physicians in improving the data base and interpreting the findings.

Aged↗

PubMed1987

Quantitative energy dispersive X-ray microanalysis of eight elements in pancreatic endocrine and exocrine cells after cryo-fixation.

Quantitative X-ray microanalysis of 8 elements was performed on ultrathin, freeze-dried sections of islets and pancreas pieces from non-inbred ob/ob-mice. Diffusion of elements was reduced to a minimum by rapidly freezing the tissue samples between nitrogen-cooled polished copper surfaces and avoiding the use of chemical fixatives and stains. The ultrastructural morphology was adequately maintained to allow measurements on secretory granules, mitochondria, cell nuclei, and cytoplasm free of these organelles. The distribution of the various elements between cellular compartments was similar in islet beta-cells and exocrine pancreas cells. However, the insulin secretory granules were outstanding in exhibiting the highest concentrations of zinc and calcium. In comparison with cytoplasm in the beta-cells, the insulin granules accumulated calcium 2-fold and zinc as much as 40-fold. As no correlation could be made for endoplasmic reticulum in the cytoplasmic measurements areas, the true accumulations above cytosol are likely to be even higher.

Animals↗

PubMed1987

[Clinical pictures of pulmonary aspergillosis].

Pulmonary infection with Aspergillus can present a variety of clinical manifestations. Essentially, allergic bronchopulmonary aspergillosis, aspergilloma, and invasive aspergillosis are the three main forms. The coexistence of more than one of these entities is not unusual. Predisposing factors for such mycotic infections include previous lung-structure damage, immunodeficiency, and disturbances in the equilibrium of the resident flora of the respiratory tract. The radiological changes in pulmonary aspergillosis are described in association with clinical presentations and laboratory findings and are demonstrated by actual examples.

Aspergillosis↗

PubMed1986

Preparation methods for quantitative electron probe X-ray microanalysis of rat exocrine pancreas: a review.

Pancreatic acinar cells are thought to secrete a fluid containing digestive enzymes and electrolytes and use e.g. calcium as a second messenger upon stimulation. Together with their pronounced morphological polarity, they provide a model system to study the effect of different preparation methods for quantitative biological electron probe X-ray microanalysis (EPXMA) of ultrathin sections. Several preparation methods i.e., freeze-drying and plastic-embedding, freeze-substitution (2 days) and freeze-drying of ultrathin cryosections have been applied to examine the retention of sodium, magnesium, phosphorus, sulfur, (chlorine), potassium and calcium in subcellular compartments (basal cytoplasm, apical cytoplasm, mitochondria and zymogen granules). In freeze-substituted samples the phosphorus, potassium and sulfur concentrations were 2-3 times lower in all compartments compared to freeze-dried, plastic-embedded samples. Intracellular potassium-to-sodium ratios obtained on frozen substituted and frozen-dried, plastic-embedded samples were considerably lower than for cryosections. Element gradients between adjacent organelles were large in frozen-dried cryosections, smaller in frozen-dried plastic- embedded samples and insignificant in frozen-substituted samples.

Animals↗

PubMed1985

A comparison of subcellular element concentrations in frozen-dried, plastic-embedded, dry-cut sections and frozen-dried cryosections.

Biological X-ray microanalysis of diffusible elements within cellular and subcellular compartments requires preparation methods to retain electrolytes in the compartments they occupied in vivo. X-ray microanalysis of frozen-dried, plastic-embedded samples has been used to quantitate electrolytes at the cellular level. We have compared the subcellular elemental distribution in dry cut sections from such samples with that in ultrathin frozen-dried cryosections. Rat pancreases were quench-frozen onto a helium-vapor-cooled copper block. Cryosections were cut at 130-150 K, transferred using a Gatan cold stage, frozen-dried in the column and analysed at 190 K. Tissue fragments were frozen-dried at 190 K, and cut on a dry knife at 293 K. Both samples provided images permitting unambiguous identification of all major compartments except the Golgi complex. Intracellular potassium-to-sodium ratios obtained on frozen-dried plastic-embedded sections were lower than for cryosections (e.g. 1.77 in basal cytoplasm in plastic sections as compared to 4.34 for cryosections) and varied with the pre-embedding procedure (e.g. 1.77 in formaldehyde-fixed as compared to 2.87 in osmium-fixed plastic sections). Potassium gradients between adjacent organelles were large in cryosections and insignificant in plastic-embedded material. Higher cytoplasmic phosphorus, potassium and sulfur concentrations were observed in cryosections. Therefore, a redistribution of electrolytes and covalently bound elements occurred subcellularly in the plastic sections. Calcium was quantifiable in most organelles in cryosections but the plastic lowered sensitivity too much to permit routine calcium quantification. We conclude that in our hands frozen-dried, plastic-embedded samples were compromised and provided lower sensitivity than cryosections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Aminoplastic standards for quantitative X-ray microanalysis of thin sections of plastic-embedded biological material.

The preparation of a set of aminoplastic standards for quantitation of sodium, magnesium, phosphorus, sulfur, chlorine, potassium, and calcium in ultrathin plastic sections of soft tissue is described. The standards are low in cost and easy to prepare and handle. They cover concentrations up to 750 mmoles/kg dry weight, and display chemical and physical properties similar to those plastic-embedded samples. The standards can be used to convert peak-to-continuum ratios obtained from the specimen to elemental concentrations. An application of these standards is shown using rat exocrine pancreas as a model. The standards can also be used to advantage for the calibration of the detector efficiency.

Animals↗

PubMed1982

Evidence for identity between the hexokinase-binding protein and the mitochondrial porin in the outer membrane of rat liver mitochondria.

Hexokinase-binding protein and mitochondrial porin were isolated from rat liver mitochondria by different procedures. It was found that the hexokinase-binding protein made lipid vesicles permeable to ADP and formed asymmetric pores in lipid bilayer membranes identical to those obtained from the mitochondrial porin. On the other hand, the mitochondrial porin confers the ability to bind hexokinase. In addition, evidence is presented that both hexokinase-binding protein and mitochondrial porin bind glycerol kinase.

Animals↗