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  • 1
    ISSN: 1433-2965
    Schlagwort(e): Bone ; Histomorphometry ; Osteoporosis ; Osteoblasts ; Osteocalcin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To assess the bone turnover abnormalities which characterize postmenopausal osteoporosis with vertebral fractures (PMOp), a transiliac bone biopsy was performed after double labeling of the mineralizing front with tetracycline in 50 untreated PMOp patients who were compared with 13 healthy age-matched volunteer females. The analysis of bone remodeling and structure parameters demonstrated that PMOp is a disease affecting both the cancellous and the endocortical envelopes and characterized by increased resorption and by a marked decrease in the osteoblastic apposition rate due to a reduced duration of bone formation. This induces a decrease in the width of both individual osteons and trabeculae. In PMOp, the wide spectrum of bone turnover as compared with the controls, associated with the typical bimodal distribution of cancellous osteoid perimeter, allowed us to identify two subsets, one with normal turnover (NT) and one with high turnover (HT) representing 30% of the cases. When compared to NT, HT was characterized by increased osteoclast number, lower bone volume, thinner osteons, increased formation at the tissue-level and markedly decreased duration of formation. In HT the marked decrease in the duration of activity of osteoblasts and the markedly increased number of osteoclasts induced a greater decrease in bone volume, despite the increase of bone formation at the tissue level. These subsets could not be distinguished by any clinical or biochemical parameter except for serum bone gla protein (osteocalcin) which was significantly higher (as a group) in HT than in NT. The underlying cause for these two subsets is unknown. We conclude that PMOp affects the cancellous and the endocortical bone. Bone loss results from a wide spectrum of bone turnover abnormalities, with two distinct subsets, one with normal turnover and one with high turnover.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 410 (1986), S. 57-63 
    ISSN: 1432-2307
    Schlagwort(e): Langerhans cells ; Basal cell carcinomas ; Squamous cell carcinomas ; Quantitative analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Epidermal Langerhans cells (LC) are required for antigen-presentation and for stimulating antigen-specific T cell activation. Similar functions may be important in the immune response to malignant skin tumours. Monoclonal anti-T6 antibody was used to examine LC population in basal and squamous cell carcinomas. Positive control labeling was performed with monoclonal anti-HLA-DR antibody. The number of T6-positive LC per mm2 of section was significantly decreased (p〈0.01) in the tumour group in comparison with a sex and age-matched control group. The number of sun-exposed and covered regions was taken into consideration in each respective group. Within the tumours, LC were found more frequently in the tumour periphery and in most differentiated tumour areas (horn pearls) than in the rest of the tumour mass. T6-positive LC were rarely found in the dermis. Moreover, LC exhibited morphological changes in specimens from tumours. Staining with anti-HLA-DR antibody revealed less numerous positive cells within tumour nests than labeling with OKT6. A relationship between T6-positive LC quantities and extent of HLA-DR-positive infiltrates around tumours could not be established. These results suggest that immunological surveillance of neoantigen-bearing tumour cells may be impaired in skin cancer. A reason for the reduced LC number may be an altered microenvironment in tumour tissue.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 35 (1983), S. 410-417 
    ISSN: 1432-0827
    Schlagwort(e): Bone remodeling ; Histomorphometry ; Corticosteroid therapy ; Osteoporosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary We have compared the mean wall thickness (MWT) and active formation periods (sigmaf(A)) of trabecular bone packets in iliac crest biopsies from 20 patients (7 male, 13 female) with corticosteroid-induced osteoporosis (CS-OP) and 20 age- and sex-matched controls. The trabecular bone volume (TBV) of the CS-OP patients (9.6%±2.2% [SD]) was significantly reduced compared to controls (19.3%±5.1%). The MWT of CS-OP patients (32.7±4.3 µm) was also significantly lower than the control value (48.0±6.2 µm). There was a positive correlation between MWT and TBV in both groups. The mineralization rate (M) of the CS-OP patients (0.54±0.25 µm/day) was within the normal range, and since there was no increase in osteoid seam thickness, so therefore was the osteoblastic appositional rate (OAR). The active formation period of trabecular bone packets (sigmaf(A)=MWT/M) was significantly lower in the CS-OP patients (55.9 ± 14.4 days) than in the control group (68.1 ± 9.4 days). MWT and sigmaf(A) both decreased with age in the control group, whereas in the CS-OP group they were independent of age. We conclude that corticosteroid therapy results in a reduction of the MWT of trabecular bone packets and, consequently, of TBV. In these patients, where the OAR was normal, the reduction in MWT was apparently caused by a shortening of the lifespan of the active osteoblastic population at the basic multicellular unit (BMU) level.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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