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  • 1
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Immunohistochemical studies were carried out on calcitonin-, somatostatin- and serotonin-reactive cells in newborn pigs and pigs at 3 weeks and 7 months old. The aim of these studies was to examine if the expression of various bioactive substances by parafollicular cells in the pig thyroid varied during development. The volume density of the follicular epithelium was nearly the same in newborn and 3-week-old piglets and significantly lower in 7-month-old animals. The volume density of calciton-in-positive cells, expressed as a percentage of the follicular epithelium density, was similar in young animals, being 12.10% and 13.03% in newborn and 3-week-old piglets, respectively. A small but significant increase to 14.40% was seen in 7-month-old pigs. Somatostatin-positive cells formed a much smaller population at all time points, but these also showed a significant increase with age (0.13%, 0.17% and 0.52% of follicular epithelium density in newborn, 3-week- and 7-month-old pigs, respectively). However the changes in the volume density of somatostatin-positive cells correlated inversely with thyroid activity, the density being highest when the activation index was lowest, suggesting that thyroid activity may be regulated by an increase in the synthesis of this inhibitory peptide. Serotonin-positive cells were extremely rare at all time points and their volume density was not calculated.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2013
    Keywords: PCB ; Pyralene-3000 ; Lung morphogenesis ; Morphometric analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of the application of commercial low chlorinated PCB Pyralene-3000 on rat lung development during late gestation were studied. In the developing lungs (17.5 to 21.5 days) the volume density (Vv) of a particular compartment and length density of potential air spaces (Lv) were determined. Significant difference (p〈0.01) in epithelium to mesenchyme ratio (Epi/Mes) occurred between the control and treated groups on day 20.5 due to an increased volume proportion of mesenchyme (Vvmes) in the treated group suggesting a small delay in maturation. Decreased volume proportion of potential airspaces (Vvair) was observed on days 18.5 and 20.5. However, no differences were found on day 21.5 in any variables studied.
    Type of Medium: Electronic Resource
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