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U Friberg

Publications and source records attributed to U Friberg.

At least 37 records · Page 2Linked to original sources
PubMed1990

Three-dimensional anatomy of the human endolymphatic sac.

Computerized and graphic three-dimensional reconstruction of a human endolymphatic duct and sac (ES) showed the ES to be a fusiform and flattened structure with marked tubularity, especially in the extraosseous region. The specimen was 18.2 mm long. It measured 60 X 200 microns at the isthmus portion of the endolymphatic duct and 200 X 7000 microns at the broadest part of the ES. The volume of the endolymphatic duct was 0.03 mm3 and of the ES, 1.85 mm3. The extraosseous ES volume represented more than two thirds of the total ES volume.

Computer Graphics↗
PubMed1990

Size variations in the lateral intercellular spaces of the endolymphatic sac induced by dietary factors.

Since much evidence suggests that the endolymphatic sac is responsible for endolymph resorption, and that the endolymphatic sac lateral intercellular spaces which are lined by the energy-dependent transport complex NA+,K(+)-ATPase are important in this process, we sought to evaluate the effects of dietary salt and a food extract that inhibits the activity of Na+,K(+)-ATPase on lateral intercellular space size. Animals fed this food factor and a high-sodium diet had significantly smaller endolymphatic sac lateral intercellular spaces than those animals fed only a high-sodium diet (analysis of variance with Scheffe's multiple comparison test, P less than 0.001). Animals fed a high-sodium diet had significantly larger endolymphatic sac lateral intercellular spaces than those animals fed a control diet only (analysis of variance with Scheffe's multiple comparison test, P less than 0.001). Results of this study suggest that dietary sodium affects endolymphatic sac fluid dynamics and that other food factors may regulate sodium metabolism, and therefore endolymphatic sac function.

Animals↗
PubMed1989

Effects of hyperosmolar substances on the endolymphatic sac.

The murine endolymphatic sac (ES) was studied 15 min to 8 hours after intravenous glycerol administration. Initially the ES showed varying degrees of obliteration and this was mostly pronounced at 15-60 min after the injection. After 2 hours the normal volume was regained and after 4 hours the lumen was dilated to 160% of its normal volume. After 6-8 hours the ES had almost regained its normal appearance. The epithelial lining showed an increase in the number of granular cells which, after two hours, reached a peak of 15.8% (p less than 0.01) compared to normal controls which showed 6.1% granular cells of total cell population in the ES. The increase of granular cells was accompanied by filling of the ES lumen with a stainable substance. The epithelial reaction may serve the purpose of counteracting decreases in endolymph pressure either in the ES or in the entire labyrinth.

Animals↗
PubMed1989

Long-term progression of Menière's disease.

A retrospective study of 161 patients with Menière's disease followed up for 9 years or more is presented. The development, with respect to hearing, caloric response, vertigo, and ability to work, was analyzed. The main functional loss was found to take place early in the course of the disease. There was an increase in bilaterality with time. A spontaneous relief in vertigo over the years has been noticed.

Adolescent↗
PubMed1988

Subcellular changes in the endolymphatic sac after administration of hyperosmolar substances.

The effects of hyperosmolar substances on the ultrastructure of the endolymphatic sac were studied in mice. Fifteen minutes after intravenous injection of urea or glycerol, subcellular changes in the endolymphatic sac were observed. These consisted of the occurrence of abundant cytoplasmic granules with a floccular or lamellar material, or both, in the light epithelial cells. Similar material was also present in the lumen of the endolymphatic sac, suggesting a common source and increased secretory activity. Mannitol caused similar changes, though less pronounced. The possibility that the alterations in the fine structure of the endolymphatic sac may be associated with a reduction in the hydrostatic fluid pressure in the rest of the labyrinth is discussed.

Animals↗
PubMed1988

Variations in surgical anatomy of the endolymphatic sac.

Twenty-nine specimens of the extraosseous portion of the human endolymphatic sac (ES) were serially sectioned longitudinally. The length and width of the extraosseous ES were measured and the surface area was calculated. As the specimens included the sigmoid sinus (SS), the relationship between the ES and the SS was analyzed. The extraosseous ES varied considerably in size. The lumen either consisted of a single tube or was subdivided into several tubules. The distal part of the ES overlapped the SS in one third of the specimens. The results indicate that a minute extraosseous ES could explain the sometimes difficult task of localizing this structure at ES surgery. The great variability in size might perhaps also explain the varying results of this surgery.

Adult↗
PubMed1988

Immunohistochemical localization of Na+, K+-ATPase in the human endolymphatic sac.

The presence and distribution of the transport protein complex Na+,K+-ATPase in the human endolymphatic sac (ES) was demonstrated immunohistochemically using a monoclonal antibody directed toward the denatured catalytic subunit of Na+,K+-ATPase from lamb kidney medulla. Our findings support an active transcellular ion exchange by the ES epithelium with subsequent passive transcellular and paracellular outflow of water. The possible role of the lateral intercellular spaces in the outflow of endolymph at the level of the ES is discussed.

Antibodies, Monoclonal↗
PubMed1988

Effects of ototoxic diuretics (loop diuretics) on the endolymphatic sac.

The acute and chronic effects of treatment with ethacrynic acid (EA) and furosemide (FU) on the structure of the murine endolymphatic sac were studied by means of light and transmission electron microscopy. The animals were treated with loop diuretics in doses which are known to cause morphological alterations of the stria vascularis and a significant reduction of the endocochlear potential. A single intravenous injection of either EA or FU resulted in immediate morphological changes such as an increase in cytoplasmic contents of endoplasmic reticulum and more prominent Golgi structures of the light cells. These cells developed membrane-bound granules and a smooth tubular network in the apical cytoplasm. These findings together with the appearance of a precipitate on the luminal aspect of the cell membrane suggested secretory activity. Ten days after daily intraperitoneal injections with loop diuretics in subtoxic doses, the epithelial cytoarchitecture of the endolymphatic sac was altered, with pronounced veiling of the light cells by the dark cells. It is concluded that the changes in the endolymphatic sac epithelium after treatment with ototoxic diuretics may not be a result of a primary toxic effect on the sac per se, but rather be secondary to alterations in fluid and ion homeostasis in the rest of the inner ear.

Animals↗
PubMed1987

Concentrations of phenoxymethylpenicillin and cefadroxil in tonsillar tissue and tonsillar surface fluid.

Thirty patients who underwent elective tonsillectomy were given phenoxymethylpenicillin (0.8 g) or cefadroxil (1 g) at different times before operation. The concentrations of the antibiotics were analysed in serum, tonsillar tissue, fluid from the surface of the tonsils, and mixed saliva. The concentrations in tonsillar tissue for both drugs were much lower than the corresponding serum concentrations. This apparently low tissue accessibility could be ascribed to the limited intracellular penetration of beta-lactam antibiotics. For both antibiotics the concentrations in the tonsillar surface fluid were higher than the levels in the tissue and well above the minimal inhibitory concentrations for streptococci. This was not due to antibiotics in saliva but probably a result of leakage from the interstitial fluid. Inability to reach active concentrations of phenoxymethylpenicillin or cefadroxil at the site of infection does not therefore seem to be a probable cause for relapse after treatment of streptococcal tonsillitis.

Adolescent↗
PubMed1987

The endolymphatic sac in a mouse mutant with cochleo-saccular degeneration. Electrophysiological and ultrastructural correlations.

The response of the endolymphatic sac to a disturbance in endolymph homeostasis was investigated by examining the sac in a mouse mutant, viable dominant spotting, which is known to exhibit primary strial dysfunction and cochleo-saccular degeneration. The function of the vascular stria was assessed by measuring the endocochlear potential and the sacs were then studied by light and transmission electron microscopy. The endolymphatic sac was found to be morphologically abnormal in these mutants, the main abnormality being the presence of granular epithelial cells, which showed clear histological signs of secretory activity. A stainable precipitate, believed to be secreted by the granular cells, was observed in the lumen of the endolymphatic sac in the mutants. The findings strengthen the view that the sac is involved in the regulation of endolymph volume and pressure.

Animals↗
PubMed1987

Human endolymphatic sac: possible mechanisms of pressure regulation.

The ultrastructure of the normal human endolymphatic sac (ES) has been observed by transmission electron microscopy (TEM). The role of the epithelium, the various regions of the subepithelial space and the general anatomy of the ES in pressure regulation were morphologically studied to generate testable hypotheses of human ES function. Light microscopic (LM) and TEM evidence of pressure regulatory mechanisms by endolymph resorption, mechanical factors, and secretory activity are presented. These mechanisms may be useful in designing experimental studies of the ES, and in interpretation of retrospective LM and TEM studies of patients with Menière's disease.

Adult↗
PubMed1987

Fixation and occurrence of dark and light cells in taste buds of fungiform papillae.

The fine structure of taste buds of the fungiform papillae of the Old World monkey Cynomolgus (Macaca fascicularis) was found to vary with the primary fixative solution used. Standard primary fixative solutions of glutaraldehyde as well as fixatives containing both formaldehyde and glutaraldehyde gave non-reproducible and usually poor results. Osmium tetroxide in distilled water gave reproducible fixation of acceptable quality. Further, when fixed in osmium tetroxide in distilled water, taste buds of the fungiform papillae did not show the dark and light cells well known from other studies. It is therefore suggested that the terms dark and light cells not be used as synonyms for receptor or support cells, since the appearance of taste bud cells is affected by fixation.

Animals↗
PubMed1987

Cytotoxic effects of cobalt-chromium alloys on fibroblasts derived from human gingiva.

The in vitro toxicity of 15 different cobalt-chromium alloys used in removable partial dentures and dental implants was studied. The composition of the alloys was determined by X-ray spectrometry. Alloys were tested on human oral fibroblasts in low density, semiconfluent or confluent cultures. The cultures were observed in a phase contrast microscope over a period of 3 wk. The alloys could be divided into three groups depending upon the degree of cell injury evoked. Group I alloys caused no cell injury. Group II alloys caused slight to moderate cell injury seen first after 3-7 days of exposure. Group III alloys caused severe cell injury with signs of cell damage detected after 12 h and total cell death after 3-14 days. The alloys' composition varied considerably with regard to cobalt, chromium and nickel as well as other components. Nevertheless, group II and III alloys had a higher nickel content than group I alloys in general.

Cells, Cultured↗
PubMed1987

Subcellular location of IGF-I in chondrocytes from rat rib growth plate.

Ultrathin cryosections of segments of growth plates from rat rib and isolated, gelatin-embedded chondrocytes from the same source were used to demonstrate the ultrastructural location of IGF-I in the different layers of the growth plate. Sections were incubated with a polyclonal rabbit antiserum to free IGF-I and colloidal gold coated with goat anti-rabbit IgGs. The gold label was present in all chondrocytes, localized almost exclusively to the cytoplasm. Particularly the cells in the proliferating zone displayed considerable amounts of gold label. In these cells, gold label was predominantly present over the rough endoplasmic reticulum and membrane bound vesicles, with only negligible gold label over the nuclei and cartilage matrix. The distribution of gold label in the chondrocytes from the proliferating zone, especially in the rough endoplasmic reticulum, strongly suggests that IGF-I can be synthesized by these cells. However, further studies are needed to verify whether there is a local synthesis of IGF-I in the chondrocytes and whether it is under control of growth hormone.

Animals↗
PubMed1987

Cell fractions from rat rib growth cartilage. Morphological and X-ray microanalytical investigation.

For in vitro studies of differentiation and proliferation of chondrocytes, a need arose to prepare enriched cell fractions for analysis of the effects of different growth promoting factors. Therefore chondrocytes were isolated from rat rib growth cartilage in young rats by collagenase digestion and subsequently three cell fractions were prepared by centrifugation in a step gradient of Percoll. In a previous paper, matrix molecules synthesized by each fraction were characterized biochemically. In the present study, ultrastructure and elemental content of the fractionated chondrocytes were analyzed by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray microanalysis. DNA-synthetic activity was measured by means of autoradiography of 3H-thymidine incorporating cells. Both morphology and elemental concentrations differed between fractions and were characteristic for each fraction. The cell fraction with the lowest density consisted of large, polygonal cells that became flattened in culture. The reduced synthetic activity and markedly lowered K content of these cells suggest that they originate from the hypertrophic zone of the growth plate. The cells in the fraction with the highest density were rather homogeneous in size and shape, and had a well developed rough endoplasmic reticulum and Golgi complex, characteristic of proliferating and resting chondrocytes. Concentrations of P and K were also significantly higher in this fraction. The fraction with intermediate density contained an admixture of cells with a predominance of proliferating cells with high DNA-synthetic activity.

Animals↗
PubMed1986

The human endolymphatic sac. An ultrastructural study.

In observing the fine structure of the human endolymphatic sac (ES) by transmission electron microscopy, we defined the cytologic characteristics of the epithelial lining of the various portions of the sac and identified five types of epithelial cells with presumably somewhat different functions. The morphologic findings may suggest that the human ES is involved in endolymph resorption and phagocytosis. In addition, there are indications that in humans the sac may be involved in pressure regulation in the internal ear. The ES has a possible role in the turnover of macular statoconia.

Capillaries↗
PubMed1986

Cell fractions from rat rib growth cartilage. Biochemical characterization of matrix molecules.

In an attempt to isolate and characterize the putative target cells for growth hormone, chondrocytes were isolated from rat rib growth cartilage and fractionated by centrifugation in a discontinuous Percoll gradient. This resulted in three cell fractions with differing properties. The fraction with the lowest density consisted mainly of large, lipid-containing cells which became flattened in subsequent culture. The cells in this fraction were fair collagen producers but synthesized only minor amounts of proteoglycans and apparently no proteoglycan aggregates. These cells probably originate in the hypertrophy zone of the growth plate. The fraction with highest density, on the other hand, consisted of small cells which upon cell culture became polygonal and surrounded with refractile matrix. They synthesized less collagen, but more proteoglycans than the low-density fraction. The proportion of proteoglycan aggregates was rather low (10-20%) but otherwise the proteoglycans were similar to those synthesized by other chondrocytes. This cell fraction was tentatively identified as cells from the upper part of the growth plate. Finally, the middle fraction was heterogeneous, consisting of cells of varying shape. This fraction synthesized large amounts of both collagen and proteoglycans. In all three cell fractions, type II collagen predominated. There were also minor amounts of (1a, 2a, 3a) collagen, and, in the two denser fractions, of type I collagen.

Animals↗