Biomedical subjects

U Kjörell

Publications and source records attributed to U Kjörell.

29 records · Page 2Linked to original sources

PubMed1984

Muscle fibre type composition in distal myopathy (Welander). An analysis with enzyme- and immuno-histochemical, gel-electrophoretic and ultrastructural techniques.

The myopathic muscle of distal myopathy (Welander's disease), the dominantly inherited neuromuscular disorder which occurs frequently in Sweden, has been characterized by electron microscopy, enzyme- and immuno-histochemistry (using antibodies against embryonic, neonatal, fast and slow myosin, and against the muscle-specific intermediate filament protein, desmin), and with gel electrophoretic techniques. Of special interest is the fact that the ultrastructural appearance of the fibres with regard to M- and Z-band structures does not fit the proposed classification criteria for ultrastructural fibre typing of normal human muscle. Furthermore, contrary to previous results, we conclusively demonstrate that the predominating fibres are of a slow-twitch type. Unexpectedly, we also observed that embryonic and neonatal myosin was expressed in some residual fibres. This emphasises the importance of supplementing stains to demonstrate activity of ATPase with myosin immuno-histochemistry in order to improve understanding of fibre type characteristics in myopathic muscles. The origin of the myopathic muscle fibres in distal myopathy could not be definitely determined, but it is suggested that neurogenic disturbances play an important part in the pathophysiology of Welander's disease.

Adenosine Triphosphatases↗

PubMed1984

Delayed muscle soreness and cytoskeletal alterations: an immunocytological study in man.

Delayed muscle soreness in man is known to be attributed to a disorganization of the myofibrils. Our aim in the present study was to investigate whether the intermediate filament system is affected as well. Biopsies were taken from the right m. vastus lateralis of six males (aged 23 +/- 3 years) suffering from severe post-exercise soreness of their thigh muscles. Intermediate filament protein was visualized by indirect immunofluorescence microscopy using an antibody specific to desmin. A typical finding in biopsies taken 3 days after exercise was abundant longitudinal "desmin" extensions. Moreover, strongly autofluorescent granules were observed beneath the sarcolemma. It is concluded that muscles subjected to unusual exercise contain myofibrillar and cytoskeletal disturbances accompanied by increased lysosomal activity.

Adult↗

PubMed1984

Distribution of intermediate filaments and actin microfilaments in parotid autoimmune sialoadenitis of Sjögren syndrome.

In order to study the importance of myoepithelial cells in the formation of parotid epi-myoepithelial islands of the autoimmune sialoadenitis in Sjögren's syndrome, the distribution of cytoskeletal elements has been investigated by electron and immunofluorescence microscopy. Antibodies to intermediate filament proteins--prekeratins, desmin and vimentin--were used as well as a 'DNase I/anti-DNase I' immunohistochemical procedure to detect actin microfilaments for characterization of myoepithelial cells compared to the other types of parotid epithelial cells. Two types of prekeratin antibodies were raised. One of these reacted preferentially with myoepithelial cells. The same type of antiserum also showed a bright fluorescence in cells located peripherally in the epi-myoepithelial islands. These island cells, however, exhibited only a very low actin microfilament content and were thus not ordinary myoepithelial cells. The other type of prekeratin antibodies reacted with all types of parotid epithelia, except acinar secretory epithelium. They also stained all island epithelial cells, but the reactivity was less in cell regions with pronounced lymphocyte infiltration. The heterogeneity between the island epithelial cells, immunohistochemically as well as ultrastructurally, indicates different stages of island formation. Interepithelial lymphocytes showed less vimentin and actin filament content in comparison with lymphoid cells outside the islands. Conclusively, typical epi-myoepithelial islands are composed of metaplastic epithelial cells of intercalated duct origin and invaded lymphoid cells, and ordinary myoepithelial cells are lacking.

Actins↗

PubMed1983

Immunological relationship between different types of bovine intermediate filaments.

In order to examine the relationship between the intermediate filaments from Purkinje fibres of the cow heart conduction system and five proposed subclasses of mammalian intermediate filaments, the gel electrophoresis-derived enzyme-linked immunosorbent assay (GEDELISA) has been used to examine the specificity and crossreactivity of our antibodies against the Purkinje fibre intermediate filament protein, skeletin. Bovine tissues known to contain intermediate filaments of the five main subclasses were examined with antiskeletin and with preimmune serum and the specific antiserum absorbed with pure skeletin as controls. The antibodies raised against Purkinje fibre skeletin reacted with all three polypeptides of the "neurofilament triplet", with glial fibrillary acidic protein (GFAP), with smooth muscle desmin and also slightly with some prekeratin subunits and with endothelial vimentin. From studies with monoclonal antibodies and amino acid sequencing, certain regions of all intermediate filaments are suggested to be structurally related. Here we show that Purkinje fibre skeletin seems to share antigenic determinants with the proposed five main classes of intermediate filaments. Our antibody is the first carefully controlled experimentally induced antibody having such properties. This might be due to the special attributes of the intermediate filament system in Purkinje fibres, which themselves have unique properties.

Animals↗

PubMed1982

The conduction system in the human heart at midgestation--immunohistochemical demonstration of the intermediate filament protein skeletin.

The intermediate filaments have during recent years increasingly attracted attention and new information on the distribution of the subunits of the filaments has become available by the use of specific antibodies. In the present study human fetal hearts at midgestation were studied with immunofluorescence microscopy for a demonstration of the intermediate filament subunit skeletin. In the ordinary ventricular and atrial myocytes the fluorescence was moderate, mainly concentrated to the Z disk levels. The proximal parts of the conduction system also showed a moderate fluorescence, while the fluorescence was intense in the cells in the peripheral parts. The shift from moderate to intense fluorescence occurred in the very proximal part of the left bundle branch and in the distal part of the intramural right bundle branch. We conclude that the conduction cells attain Purkinje fibre-like characteristics at these levels, as evidenced by the content of skeletin. Furthermore, the human fetal Purkinje fibres are more easily distinguished with the technique used herein than with conventional histological techniques. The observed differences in content of skeletin are discussed in terms of the cytoskeletal function of intermediate filaments and the embryology of the conduction system.

Cholinesterases↗

PubMed1982

Differentiation of the myofibrils and the intermediate filament system during postnatal development of the rat heart.

The differentiation of the myofibrils and the intermediate filament system during postnatal development of the rat heart has been investigated. Several aspects of some of the structural proteins, that means the intermediate filament subunit skeletin, myosin, and the myofibrillar M-line proteins MM-creatine kinase and myomesin have been studied by using gel electrophoresis as well as enzyme and immunohistochemical techniques in combination with electron microscopy of both plastic and cryosectional material. We show that marked changes take place in the organization of the intermediate filament system and in the contractile apparatus, both in atria and in ventricles of the rat heart during postnatal development. In the newborn rats no dense myofibrillar M-bands were present in the M-region and the sarcomeric bands were irregular while in the four-week-old rats dense M-bands composed of a set of five crossbridges interconnecting the thick filaments were present. The sarcomeric bands were now regular. These observations are related to the presence of different isomyosins in the atria and in the ventricles of the newborn and the four-week-old rats, to the observation that MM-creatine kinase was only present in the M-region in the four-week old rats and to the physiological maturation of the heart.

Animals↗

PubMed1982

Identification of a complex between alpha-actinin and the intermediate filament subunit skeletin in bovine heart Purkinje fibres.

A three-dimensional cytoskeleton, morphologically composed of intermediate filaments, desmosomes, and Z-disks, remains in bovine heart Purkinje fibres after extraction with Triton X-100 and low and high ionic strength solutions. Biochemically this cytoskeleton mainly consists of skeletin (Mr approximately 55 000) and of alpha-actinin (Mr approximately 95 000). Minor high molecular weight components are also present. By gel electrophoresis-derived enzyme-linked immunosorbent assay (GEDELISA) we show here that a 150 000-dalton component is a complex of alpha-actinin and skeletin. Furthermore, this 150 000-dalton component has now been purified and can be converted into 95 000- and 55 000-dalton subunits by reduction with a high concentration of beta-mercaptoethanol and heating. We also show that solubilized pure skeletin and pure alpha-ctinin from Purkinje fibres, after mixing, partly form a stable complex with a molecular weight of about 150 000 daltons.

Actinin↗

PubMed1980

Skeletin immunoreactivity in peripheral nerves.

By use of monospecific antibodies against the cow heart intermediate filament protein, skeletin, an antigenic relationship between skeletin and neurofilament protein of peripheral nerves is demonstrated. Crossreactivity is also demonstrated in the filament-containing Schwann cells. The results are consistent with the existence of several subclasses of related intermediate-sized filament proteins.

Animals↗

PubMedDate not supplied

Ultrastructural and immunohistochemical aspects of carcinoma in mixed tumors.

Four cases of malignant mixed tumor (carcinoma in pleomorphic adenomas) were studied for ultrastructural appearance and for the presence of cytokeratins and vimentin. Ultrastructurally, both squamous and glandular epithelial differentiation were found not only in the same tumor but also within the same cell. One tumor showed mainly mesenchymal differentiation with fibroblast-like cells. The intermediate filament expression of benign mixed tumors (i.e., both cytokeratin and vimentin content) were found in two of the three malignant tumors investigated. In the third tumor, only cytokeratins were found. Thus, the filament content of mixed tumors may change when the tumor becomes malignant. This change does not always parallel a change in morphology. Although one tumor was clearly epithelial ultrastructurally and another mostly mesenchymal, both did contain both cytokeratins and vimentin.

Adenoma, Pleomorphic↗

PubMedDate not supplied

Immunohistochemical and ultrastructural observations on adenoid cystic carcinoma of salivary glands. With special reference to intermediate filaments and proteoglycan particles.

In adenoid cystic carcinoma (ACC) of salivary gland origin, intermediate filaments of tumour cells were investigated by immunohistochemical techniques and complex carbohydrates within the pseudocysts by ultrastructural methods. The intermediate filament proteins vimentin and cytokeratin were found in most neoplastic cells. The pseudocysts of the tumours were found to contain proteoglycan particles stainable after glutaraldehyde fixation--but not after osmium fixation alone. Ruthenium red (cationic dye) enhanced the staining whereas periodic acid-chromic acid-silver methenamine staining or phosphotungstic acid staining did not visualize the proteoglycan particles mainly containing acid proteoglycans which are normally produced by mesenchymal tissue. The cells of adenoid cystic carcinoma thus have an intermediate filament content and produce complex carbohydrates characteristic of both epithelial and mesenchymal tissue. Hence, an origin in an undifferentiated pluripotential cell seems plausible.

Carcinoma, Adenoid Cystic↗

PubMedDate not supplied

Increased content of bombesin/GRP in human synovial fluid in early arthritis: different pattern compared with substance P.

OBJECTIVE: Bombesin (BN) and the mammalian homologue gastrin-releasing peptide (GRP) are known trophic factors, neurotransmitters and paracrine hormones. BN/GRP has not previously been demonstrated in synovial fluid. In this study, the amounts of BN/GRP and substance P (SP) present in synovial fluid from the knee joints of patients with rheumatoid arthritis (RA) and of healthy controls were measured. METHODS: Synovial fluid from the knee joint was collected from patients with either longstanding RA (n = 32) or early arthritis (symptoms for < 12 months; n = 9) and from control subjects, i.e., individuals without known joint disease (n = 10). These samples were analyzed using radioimmunoassays. RESULTS: Levels of BN/GRP-like peptide were below the assay detection limits in synovial fluid from controls. Detectable levels of immunoreactive BN/GRP were present in the majority of patients with either longstanding RA or early arthritis. The levels were significantly higher in the synovial fluid from patients classified as having early arthritis compared with those with longstanding RA (p < 0.05). There was a strong correlation between BN/GRP levels and the number of leukocytes in the synovial fluid in the patients with early arthritis. The levels of SP-like peptide in the patients, whether with early arthritis or longstanding RA, were significantly elevated compared with controls. However, there was no difference in the levels between these two patient groups. CONCLUSIONS: These observations show that BN/GRP-like peptide is present in the synovial fluid of joints affected by arthritis and that the pattern of BN/GRP increase differs from that of SP. It appears as if the presence of BN/GRP is particularly related to the early processes of joint involvement. These observations are of interest because BN/GRP has well-known trophic and paracrine effects and chondrocytes have recently been shown to produce neuropeptides such as BN/GRP.

Adult↗