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Biomedical subjects

U Friberg

Publications and source records attributed to U Friberg.

At least 55 records · Page 3Linked to original sources
PubMed1985

Basal lamina pathology of the utricle and endolymphatic duct in Ménière's disease.

Labyrinthectomy was performed in a patient with a 4-year history of Ménière's disease. The utricle and the proximal portion of the endolymphatic duct were studied using light and electron microscopy. The epithelium varied in height from squamous to columnar. The basal lamina lining the columnar epithelial cells showed marked thickening which was visible in the light microscope. Electron microscopy revealed that the basal lamina had a fibrillar structure. The basal lamina of adjacent blood vessels also showed pathologic thickening with similar fibrillar texture. The significance of basal lamina thickening in association with Ménière's disease is discussed.

Ear, Inner↗
PubMed1985

Effect of human growth hormone on proteoglycan synthesis in cultured rat chondrocytes.

We have previously demonstrated that hGH stimulates DNA synthesis in cultured chondrocytes in the absence of serum. The present study is concerned with the effects of hGH on proteoglycan synthesis by cultured chondrocytes. Chondrocytes were isolated from rat rib growth cartilage by collagenase digestion, plated in plastic dishes, transferred to serum-free MCDB 104 medium, and incubated for 24 h to establish growth arrest. The cultures were then preincubated for 0-24 h with various concentrations of hGH and ovine prolactin (oPrl) and finally pulse-labelled for 30 min with radioactive sulphate in the presence of hormone. hGH, but not oPrl, stimulated sulphate incorporation with an apparent maximum at 50 ng/ml (approximately 170%). The stimulatory effect was apparent after 2 h and maximal after 3h preincubation. After 12 h the stimulatory effect had decreased to insignificant levels. Qualitative analysis of isolated proteoglycans indicated that the stimulation of sulphate incorporation by hGH is exerted at the level of protein synthesis with little effect on glycosylation and sulphation. Further experiments are required to demonstrate whether the stimulatory effect on proteoglycan synthesis is a specific phenomenon or represents one aspect of a general stimulation on cell metabolism in preparation for DNA synthesis.

Animals↗
PubMed1985

The lateral intercellular spaces in the endolymphatic sac. A pathway for fluid transport?

The lateral intercellular spaces (LIS) in the epithelium of the endolymphatic sac in different mammals were studied using light and transmission electron microscopy. The reason for the study was that widened LIS are known to occur in fluid transporting epithelia, where they may reflect transepithelial flux of water and solutes. Increased knowledge about LIS may lead to further insight into the mechanisms of endolymph resorption in the endolymphatic sac. The effects of various fixatives, fixation methods and osmolality, and also of surgical labyrinthectomy, on the ultrastructure of LIS were investigated. Widened LIS regularly occurred in the mammalian endolymphatic sac and seem to reflect an in vivo condition. It is thought that LIS may form a pathway for transepithelial water flow in the endolymphatic sac. A hypothetical model of the function of LIS during transepithelial fluid movement in the sac is presented.

Animals↗
PubMed1984

Analysis of collagen types synthesized by rabbit ear cartilage chondrocytes in vivo and in vitro.

This study compares the collagen types present in rabbit ear cartilage with those synthesized by dissociated chondrocytes in cell culture. The cartilage was first extracted with 4M-guanidinium chloride to remove proteoglycans. This step also extracted type I collagen. After pepsin solubilization of the residue, three additional, genetically distinct collagen types could be separated by fractional salt precipitation. On SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis they were identified as type II collagen, (1 alpha, 2 alpha, 3 alpha) collagen and M-collagen fragments, a collagen pattern identical with that found in hyaline cartilage. Types I, II, (1 alpha, 2 alpha, 3 alpha) and M-collagen fragments represent 20, 75, 3.5, and 1% respectively of the total collagen. In frozen sections of ear cartilage, type II collagen was located by immunofluorescence staining in the extracellular matrix, whereas type I collagen was closely associated with the chondrocytes. Within 24h after release from elastic cartilage by enzymic digestion, auricular chondrocytes began to synthesize type III collagen, in addition to the above-mentioned collagens. This was shown after labelling of freshly dissociated chondrocytes with [3H]proline 1 day after plating, fractionation of the pepsin-treated collagens from medium and cell layer by NaCl precipitation, and analysis of the fractions by CM(carboxymethyl)-cellulose chromatography and SDS/polyacrylamide-gel electrophoresis. The 0.8 M-NaCl precipitate of cell-layer extracts consisted predominantly of type II collagen. The 0.8 M-NaCl precipitate obtained from the medium contained type I, II, and III collagen. In the supernatant of the 0.8 M-NaCl precipitation remained, both in the cell extract and medium, predominantly 1 alpha-, 2 alpha-, and 3 alpha-chains and M-collagen fragments. These results indicate that auricular chondrocytes are similar to chondrocytes from hyaline cartilage in that they produce, with the exception of type I collagen, the same collagen types in vivo, but change their cellular phenotype more rapidly after transfer to monolayer culture, as indicated by the prompt onset of type III collagen synthesis.

Animals↗
PubMed1984

Human endolymphatic duct. An ultrastructural study.

The fine structure of the human endolymphatic duct was observed by transmission electron microscopy. Well-preserved specimens were obtained after fixation of inner ear tissue by perilymphatic perfusion. The morphologic findings seemed to be in accordance with earlier propositions that the human endolymphatic duct may be involved in endolymph resorption. The duct was found to contain otoconialike bodies, suggesting that the endolymphatic duct and sac in man may also play a role in the turnover of macular otoconia.

Adult↗
PubMed1984

The ultrastructure of the human endolymphatic duct.

The fine structure of the human endolymphatic duct as observed at transmission electron microscopy (TEM) is described. After fixation of inner ears by perilymphatic perfusion adequately preserved tissue specimens were obtained. Our morphological findings seem to be in accordance with the earlier proposition that the human endolymphatic duct may be involved in endolymph resorption. The duct was found to contain otoconia-like bodies, suggesting that the endolymphatic duct and sac, may play a role in the turnover of macular otoconia.

Adult↗
PubMed1984

The natural course of Meniere's disease.

A retrospective study of 161 Meniere patients followed up for 9 years or more is presented. The development with respect to hearing, caloric response, vertigo and ability to work was analysed. The main functional loss was found to take place early in the course of the disease. There was an increase in bilaterality with time.

Adolescent↗
PubMed1983

Synthesis of proteoglycans, collagen, and elastin by cultures of rabbit auricular chondrocytes--relation to age of the donor.

Chondrocytes were isolated from the auricular cartilage of rabbits, aged 1 week to 30 months, and grown in short-term cell culture. The cells from the 1-week animals were small, polygonal, and mononucleated, while the chondrocytes from the older animals were larger, rounded, and frequently binucleated. The synthesis of proteoglycans, collagen, and elastin was determined by isotope incubation. Chemical characterization of the proteoglycans was also performed. The production of the matrix macromolecules showed a clear age dependence with peak synthesis occurring at different ages. Proteoglycans were actively synthesized by chondrocytes from all age groups with a broad maximum between 2 weeks and 5 months followed by a sharp decline to about 50% of the 1-week level at 12-30 months. Collagen synthesis peaked at 2 weeks, declining progressively thereafter to about 60% of the 1-week level at 30 months. Elastin synthesis was highest in the 1-week cultures and thereafter fell quickly to very low levels. In all age groups the chondrocytes synthesized predominantly cartilage-typic proteoglycans, i.e., large aggregate forming molecules containing chondroitin sulfate. Monomers and aggregates showed a size maximum at 2-8 weeks. The degree of sulfation of the chondroitin sulfate and the proportion of 6-sulfate increased with age. These findings support the concept of "age programs" for the biosynthesis and turnover of different matrix macromolecules.

Aging↗
PubMed1983

Specific binding of growth hormone to isolated chondrocytes from rabbit ear and epiphyseal plate.

Chondrocytes were isolated from rabbit ear, epiphyseal and rib cartilage, and their ability to bind 125I-labeled human growth hormone (hGH) was investigated. The total binding of hormone to ear chondrocytes increased with time until 4-6 h, whereas non-specific binding did not increase. Total binding was 1-3% of total counts added, and non-specific binding was 10-20% of total binding. Unlabeled hGH, bGH and oPRL competed with the binding of labeled hGH in a dose-dependent manner with half-maximal binding at concentrations of 10-20 ng/ml (hGH) and 100 ng/ml (bGH and oPRL). The two latter hormones displaced almost all specific binding of hGH at higher concentrations. Ear chondrocytes from newborn to 4 week old rabbits all showed specific binding of hGH with no clear age dependence. Rib chondrocytes, on the other hand, showed very little specific binding. Epiphyseal chondrocytes from newborn animals yielded intermediate binding values. The finding of specific hGH binding by cultured chondrocytes supports the concept of a direct effect of GH on chondrocytes.

Animals↗
PubMed1983

X-ray microanalysis of cultured chondrocytes.

Methodological aspects of X-ray microanalysis of cultured chondrocytes from rabbit auricular cartilage were investigated. The cells were grown on a Formvar-film covered carbon specimen holder with a hole, which allowed examination in STEM. Several different fluids for washing away the culture medium from the cells were used. The effect of these fluids on the elemental composition of the cells was studied. The composition of cultured chondrocytes was compared with that of auricular chondrocytes in situ. Washing with 0.3 M sucrose gave the most satisfactory results. Subsequently, the specimen holders could be frozen in liquid nitrogen and the cells freeze-dried. The effects of human growth hormone on rabbit chondrocytes were investigated by X-ray microanalysis and transmission electron microscopy. Although no ultrastructural effects of hormone treatment could be observed, marked changes in the elemental concentrations in nucleus and cytoplasm of the chondrocytes were detected.

Animals↗
PubMed1981

Fine structure of taste buds in the human fungiform papilla.

The fine structure of taste buds on fungiform papillae from man was examined with particular reference to different cell types and to cell-nerve contacts. Most of the elongated cells of the taste bud extended from the basal lamina to the apical pore, terminating in irregular microvilli. The cells contained clear apical vesicles, mitochondria, filament bundles and Golgi cisternae. Unmyelinated nerve fibers, containing mitochondria as well as both dense-cored and clear synaptic-type vesicles, were scattered throughout the whole taste bud but were most numerous at the base. The nerve fibers were either in simple appositional contact or in mesaxonal contact with the taste bud cell. Typical synapses with the postsynaptic densities in the taste bud cell were sometimes seen. In addition, single taste bud cells were observed to have more than one type of contact with nerve fibers. As in the Old World monkey Cynomolgus it was not possible to distinguish different cell types described earlier in other species.

Adult↗
PubMed1981

Taste buds of the fungiform papillae in Cynomolgus monkey.

A study of the number of taste buds borne on 145 fungiform papillae from 20 Cynomolgus monkeys showed that, in contrast to the situation in man, most papillae are bud-bearing. The fine structure of taste buds on fungiform papillae of these monkeys was also examined. The cells contained clear apical vesicles, mitochondria, filament bundles and stacks of Golgi cisternae. Nerve fibres containing mitochondria, as well as clear and dense-cored vesicles, were scattered throughout the whole bud, but were more numerous near the base. It was, however, not possible to distinguish different cell types in these taste buds as a function of cell shape, electron density of the ground cytoplasm, presence of different organelles or relation to nerve processes.

Animals↗
PubMed1980

Human taste: response and taste bud number in fungiform papillae.

The number of basic taste qualities registered by single human fungiform papillae is correlated with the number of taste buds borne on these papillae. Multiple sensitivity was demonstrated both in single fungiform papillae and in single taste buds, with response to all four of the basic taste qualities occuring in a single taste bud.

Adolescent↗
PubMed1980

Cold and metabolic inhibitor effects on cytoplasmic microtubules and the Golgi complex in cultured rat epiphyseal chondrocytes.

Previous work has shown that exposure of cultured chondrocytes to colchicine leads to disappearance of microtubules and dispersion of the dictyosomes of the Golgi complex throughout the cytoplasm. Here, the effects of cold and metabolic inhibitors on cultured chondrocytes have been investigated in order to characterize further the relationship between these organelle systems. After incubation of cells for 24h at 4 degrees C most, but not all microtubules disappeared, indicating the existence of cold-resistant microtubules. Dictyosomes remained united in one area, until transfer of cultures to 37 degrees C, when they dispersed throughout the cytoplasm in about one-third of the cells. In cells exposed simultaneously to cold and colchicine, microtubules disappeared completely, but spreading of dictyosomes occurred only in some cells and became generalized first upon warming. Application of the metabolic inhibitors sodium azide or sodium fluoride (10(-2) M) or 2-deoxyglucose (5 X 10(-2) M) together with sodium cyanide (10(-2) M) inhibited microtubule removal by colchicine. Consequently, spreading of the Golgi complex was prevented. These findings support the concept of an important role of microtubules in the organization of the Golgi complex. Moreover, depolymerization of microtubules by colchicine appears to be an energy dependent process.

Animals↗
PubMed1980

Effects of dental root posts on human gingival fibroblasts in vitro.

Dental root posts of gold-plated brass and German silver caused injury of human gingival fibroblasts in vitro. Posts made of stainless steel, titanium and gold alloys showed no discernible effects of cell morphology of apparent metabolic activity during the two-week period of observation.

Cells, Cultured↗
PubMed1979

Comparison of the in vitro effects of colchicine and its derivative colchiceine on chondrocyte morphology and function.

Colchiceine is a colchicine-metabolite which has been reported to inhibit axonal transport although not binding to brain tubulin. In the present study, colchiceine was shown not to depolymerize cytoplasmic microtubules, nor to mimic other effects of colchicine on the ultrastructure of cultured chondrocytes. In addition, the synthesis of proteoglycans was inhibited by colchicine but slightly stimulated by colchiceine. These results support the idea that the disturbances in cultured chondrocytes caused by colchicine are specifically related to a loss of cytoplasmic microtubules.

Animals↗
PubMed1979

Electron microscopic and cytochemical studies of rat aorta. Intracellular vesicles containing elastin- and collagen-like material.

Small, rounded vesicles with a dense core of amorphous material were observed in all cell types in the young rat aorta, that is, endothelial cells, smooth muscle cells and fibroblasts. They were particularly numerous in the Golgi complex but were also found in the cell periphery. The content of the vesicles had staining characteristics identical to those of elastin. Material of the same type was also found in cisternae on the maturing side of the dictyosomes and in vesicles budding from them. Reaction product for thiamine pyrophosphatase was present in both these structures, indicating that the Golgi complex is responsible for the formation of the dense-cored vesicles. This was further supported by the absence of reaction product for acid phosphatase in the cisternae and in the vesicles. Moreover, no uptake of exogenous markers was noted in the latter. On the basis of these findings it is suggested that the dense-cored vesicles have a secretory function and contain precursors of elastin. Elongated vesicles or profiles containing collagen fibrils were observed in smooth muscle cells and fibroblasts. In the cell periphery, these vesicles were often found to communicate with the extracellular space. Further inside the cells, they showed a close spatial relationship to the Golgi complex. Neither thiamine pyrophosphatase nor acid phosphatase activity was demonstrated in the elongated vesicles. Like the plasma membrane, their limiting membrane was positively stained for alkaline phosphatase. On the basis of these findings and the absence of uptake of exogenous markers in them, it is suggested that the elongated vesicles represent a means for collagen secretion in the growing aortic wall. The Golgi complex is believed to be involved in the transfer of collagen to these vesicles.

Animals↗