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Biomedical subjects

U Friberg

Publications and source records attributed to U Friberg.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Growth hormone stimulates the proliferation of cultured chondrocytes from rabbit ear and rat rib growth cartilage.

The effect of growth hormone (GH) on various growth processes is generally considered to be indirect, mediated by GH-dependent plasma factors--somatomedins--which are produced mainly in the liver. In vitro, somatomedins stimulate a number of processes that apparently are associated with cell growth. It has been difficult, however, to induce skeletal growth by the administration of somatomedins in vivo. Daily injections of a partially purified somatomedin preparation failed to induce accumulated longitudinal bone growth using the intravital marker tetracycline or by measuring the nose-to-tail length. Administration of insulin-like growth factor I (IGF I) which is probably identical to somatomedin C, to hypophysectomized rats has been reported to increase the width of the epiphyseal plate. But although this suggests an in vivo effect of IGF I on longitudinal bone growth, such an effect has not been directly demonstrated. Recently, we reported that local administration of human GH (hGH) into the proximal cartilage growth plate of the tibia of hypophysectomized rats stimulated longitudinal bone growth on the side injected with the hormone. Furthermore, we have identified specific binding sites for hGH in cultured chondrocytes from rabbit ear and epiphyses. Here, we show that hGH, but not the structurally related polypeptides ovine prolactin or human prolactin, stimulates DNA synthesis in chondrocytes from rabbit ear and from rat rib growth plate, cultured in a chemically defined medium without the addition of serum. Our results suggest that GH directly initiates proliferation in mammalian chondrocytes.

Animals↗
PubMedDate not supplied

Stereocilia-like structures in the endolymphatic sac in Ménière's disease and acoustic neuroma.

The vestibular aqueduct was surgically removed in 3 patients undergoing labyrinthectomy due to severe Ménière's disease (MD). Stereocilia-like structures were found in the luminal contents of the endolymphatic sac (ES) in all of these patients. The ES from 18 patients with acoustic neuroma were used as controls. In 1 of these, numerous stereocilia-like structures were found in the ES and in 3 additional patients, a few isolated cilia-like structures were disclosed. The findings may suggest an ongoing hair cell degeneration in the inner ear that is more advanced in patients with MD. The data also suggest that the endolymphatic duct is patent and that a longitudinal flow of endolymph also occurs in patients with MD.

Adult↗