Comparison of two subsampling methods for electron microscopic morphometry*

Müller, Alfred; Cruz‐Orive, Luis M.; Gehr, Peter; Weibel, Ewald R.

doi:10.1111/j.1365-2818.1981.tb01278.x

Cited by 57 publications

(22 citation statements)

References 8 publications

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“…Five of the 10 blocks per left lung were randomly taken, and one technically perfect section per block was viewed in a Philips EM 200. Eight quadrants per section containing lung tissue were photographed by systematic random sampling (24) and recorded on 35-mm film at ϫ1,200 primary magnification. Fields of view containing only air and no tissue were not photographed but were recorded separately and included in the calculations.…”

Section: Methodsmentioning

confidence: 99%

Effects of Neonatal High-Dose Short-Term Glucocorticoid Treatment on the Lung: A Morphologic and Morphometric Study in the Rat

Tschanz

2003

Pediatric Research

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Glucocorticoids are often applied in neonatology and perinatology to fight the problems of respiratory distress and chronic lung disease. There are, however, many controversies regarding the adverse side effects and long-term clinical benefits of this therapeutic approach. In rats, glucocorticoids are known to seriously impair the formation of alveoli when applied during the first two postnatal weeks even at very low dosage. The current study investigates short-term and long-term glucocorticoid effects on the rat lung by means of morphologic and morphometric observations at light and electron microscopic levels. Application of a high-dosage protocol for only few days resulted in a marked acceleration of lung development with a precocious microvascular maturation resulting in single capillary network septa in the first 4 postnatal days. By postnatal d 10, the lung morphologic phenotype showed a step back in the maturational state, with an increased number of septa with double capillary layer, followed by an exceptional second round of the alveolarization process. As a result of this process, there was an almost complete recovery in the parenchymal lung structure by postnatal d 36, and by d 60, there were virtually no qualitative or quantitative differences between experimental and control rats. These findings indicate that both dosage and duration of glucocorticoid therapy in the early postnatal period are very critical with respect to lung development and maturation and that a careful therapeutic strategy can minimize late sequelae of treatment. GC therapy is widely used in the prenatal and postnatal periods either as a prophylactic or curative measure. Use of prenatal GCs is often motivated by the observed positive effects on lung maturation and surfactant production in preterm babies (1, 2), who otherwise stand a high chance of developing respiratory distress syndrome (3) and subsequent chronic lung disease, also known as bronchopulmonary dysplasia (4, 5). The positive effects of postnatal GCs on pulmonary inflammatory processes (6, 7) and the prophylactic effects against hyperoxic lung injury (8) seem to improve the survival chances of preterm neonates. In perinatal medicine, a variety of therapeutic schemes have been adopted, but controversies regarding the long-term benefits and the negative side effects of GC in neonatology abound (9 -11). Indeed, besides the apparent benefits of GC therapy, adverse effects on lung maturation have been reported in animal experiments (12, 13). Furthermore, reserves have been expressed over the general outcome of treated newborns (14,15). In the recent past, there have been numerous studies on the positive and negative effects of postnatal GC therapy, but as noted by Barrington (16), there are no published long-term pulmonary data.Previously we have indicated that long-term administration of minute doses of GC results in a permanent impairment of lung alveolarization in postnatal rats (17,18). Alveolarization is achieved by subdivision of the preexisting saccular air spaces ...

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Section: Methodsmentioning

confidence: 99%

Effects of Neonatal High-Dose Short-Term Glucocorticoid Treatment on the Lung: A Morphologic and Morphometric Study in the Rat

Tschanz

2003

Pediatric Research

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“…A grey level threshold was set for stained collagen, and the area stained was calculated as a percentage of the total area (BioScan, Inc., Edmonds, WA). The sections were sampled in a nonbiased (blinded) systematic fashion ( 11 ). For analysis ofleft and right ventricle interstitial collagen, each ventricle was scanned in entirety on the microscope, and every fifth field was used for analysis.…”

Section: Methodsmentioning

confidence: 99%

Mineralocorticoids, hypertension, and cardiac fibrosis.

et al. 1994

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Uninephrectomized rats drinking 1% sodium chloride were given aldosterone (Aldo, 0.75 gg/h, subcutaneous Is.c.I infusion), deoxycorticosterone (DOC, 20 mg/wk, s.c.), corticosterone (B, 2 mg/d, s.c.), or the antiglucocorticoid-antiprogestin RU486 (2 mg/d, s.c.) for 8 wk, and hemodynamic and tissue responses were compared with a non-steroid-treated control group. Aldo and DOC markedly increased systolic BP and caused considerable (40-50%) cardiac hypertrophy; B and RU486 caused neither hypertension nor cardiac hypertrophy. Measurements of ventricular cross-sectional areas showed hypertrophy due to an increase in mass of the left ventricle only. Cardiac hydroxyproline concentration was increased considerably by Aldo and DOC, to a lesser degree by RU486, and not by B. Aldo markedly elevated left ventricular interstitial collagen (2.5-fold vs control, P < 0.01 vs all groups); other steroid treatments also increased interstitial collagen over control (DOC X 1.8-, RU486 X 1.6-, B X 13-fold), with identical responses for right and left ventricles (r = 0.94). A different pattern of perivascular fibrosis was noted; DOC elevated perivascular collagen (2.1-fold vs control, P < 0.01 vs all other groups); RU486 raised levels 1.4-fold vs control, but neither Aldo nor B significantly affected perivascular collagen. These data are consistent with interstitial cardiac fibrosis reflecting type I (mineralocorticoid) receptor occupancy by administered Aldo or DOC, or by elevated endogenous B after type II (glucocorticoid) receptor blockade after RU486 administration; perivascular fibrosis may reflect a composite response after type I receptor agonist/type II glucocorticoid receptor antagonist occupancy. (J. Clin. Invest. 1994.93:2578-2583

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“…Twenty-five quadrates per section were photographed by systematic random sampling [20] and recorded on 35-mm film. Positive contact copies of film material were viewed in a projec tion unit at a final magnification of x 12,000.…”

Section: Electron-microscopic Morphometrymentioning

confidence: 99%

Influence of Postnatally Administered Glucocorticoids on Rat Lung Growth

Tschanz¹,

Damke²,

Burri³

1995

Neonatology

175

104

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Postnatal formation of alveoli can be largely prevented by glucocorticoid treatment, which accelerates alveolar wall thinning and inhibits outgrowth of new interalveolar septa. Since a double capillary network is a prerequisite for interalveolar wall formation, we hypothesized that glucocorticoid treatment inhibited alveolar formation, indirectly, by inducing precocious microvascular maturation. Between 4 and 60 days we followed up qualitatively and quantitatively the effects of 2 weeks (days 2–15) of daily Decadron® (Dexamethasone phosphate) injections on the lung structure. Glucocorticoid induced only small changes in body weight or lung volume. However, during the first 2 weeks, it accelerated alveolar wall thinning and microvascular maturation and partly suppressed the outgrowth of new interalveolar septa. In Decadron-treated rats, the interstitial tissue mass was significantly reduced during the first 2 weeks, and a larger alveolar surface area was endowed with a capillary monolayer on days 10 and 13. One week after drug withdrawal, the trend towards precocious maturation of the lung was reversed. Lipofibroblasts reappeared, and inter-airspace septa regressed towards a more immature state. We found indications of a second burst of alveolization by resumption of secondary septa formation. The late sequelae of Decadron treatment (day 60) were manifested as an ‘emphysematous’ condition of the lungs, with larger and fewer airspaces, the delayed alveolization being insufficient to compensate for the initial deficit.

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Comparison of two subsampling methods for electron microscopic morphometry*

Cited by 57 publications

References 8 publications

Effects of Neonatal High-Dose Short-Term Glucocorticoid Treatment on the Lung: A Morphologic and Morphometric Study in the Rat

Effects of Neonatal High-Dose Short-Term Glucocorticoid Treatment on the Lung: A Morphologic and Morphometric Study in the Rat

Mineralocorticoids, hypertension, and cardiac fibrosis.

Influence of Postnatally Administered Glucocorticoids on Rat Lung Growth

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