Konrad Morgenroth

Morphological Features of the Interaction Between Mucus and Surfactant on the Bronchial Mucosa

The secretion layer over the bronchial epithelium was investigated on human biopsy material. In the sol phase of the secretion, phospholipid membranes stretched out or arranged in vesicular structures could regularly be demonstrated. They displayed the same structure as the surfactant material in the alveolar space. It can be inferred therefrom that the surfactant is excreted via the bronchial system. It probably contributes to the stabilization of the sol phase of the mucus and thus influences the sliding capacity of the gel phase. So the surfactant has an important function in maintaining mucociliary clearance at the bronchial mucosa.

The role of chlamydia in the pathogenesis of pulmonary emphysema. Electron microscopy and immunofluorescence reveal corresponding findings as in atherosclerosis.

Abstract  Chlamydia pneumoniae has been detected in atherosclerotic plaques by various means. Chlamydiae are able to cause persistent infections. Serologically elevated antibody titers are found in severe chronic obstructive pulmonary disease. In atherosclerosis and pulmonary emphysema, inflammatory reactions can be seen by means of light microscopy. Specimens from patients with obliterative arteriosclerosis undergoing thrombendarteriectomy and with advanced emphysema undergoing lung volume reduction surgery were examined using scanning (SEM) and transmission (TEM) electron microscopy, and using immunofluorescence with monoclonal antibodies and antiserum against chlamydiae. SEM shows spherical bodies (SBs) with a diameter from 0.3 µm to 0.6 µm on the surface of the alveoli and bronchioles, as well as in atherosclerotic plaques. In atherosclerosis and emphysema, SBs reveal a double membrane, adherence to collagen fibers, tissue destruction, as well as intracellular and interstitial localization in TEM. They show in parts a densely packed central structure. SBs are seen both in alpha-1-antitrypsin deficiency emphysema and smoker’s emphysema. Using immunofluorescence microscopy, spots are seen in corresponding distributions to the SBs. Morphological findings are typical for aberrant chlamydiae seen in persistent infections. Chronic infection and bacterial colonization associated with progressive disease seems to be relevant not only in atherosclerosis but also in pulmonary emphysema.

Infection of Murine Precision Cut Lung Slices (PCLS) with Respiratory Syncytial Virus (RSV) and Chlamydophila pneumoniae Using the Krumdieck Technique

The Krumdieck technique allows the investigation of the so-called precision cut lung slices (PCLS) with a special microtome. It is thus possible to evaluate morphologic changes over a longer period of time using only a small group of animals. Chlamydophila pneumoniae (Cp) and respiratory syncytial virus (RSV) proved to be important causes of pneumonia, rhinitis and exacerbations of asthma bronchiale, as well as of lower respiratory tract infections in young children. PCLS should be tested for their suitability as an in vitro model for these infections. The PCLS were infected with Cp and RSV over different periods of time. Investigations were carried out by light and transmission electron microscopy (TEM). Furthermore, immunofluorescence (IF) studies with antibodies against bacterial or viral proteins and cell-specific markers were done using confocal laser scanning microscopy (CLSM). Non-infected and infected PCLS showed a well-preserved morphology up to 72 hours. After short infection intervals, typical inclusions of Cp or RSV were detected in vacuoles of different cell types. Infection and cell types could be verified using IF. Cytopathic effects were not prominent. Ciliary beat was detectable up to 96 hours after infection. This in vitro technique offers the possibility of studying mechanisms and effects of bacterial and viral infections on viable tissue complexes.

In vitro study of the bronchial mucosa duringPseudomonas aeruginosa infection

The route of bacterial infection of the lower respiratory tract is generally one of descent subsequent to colonisation of the oral and oropharyngeal mucosa. The interaction betweenPseudomonas aeruginosa (wild type) and the bronchial epithelium was studied in bronchial mucosal probes cultured in tissue culture medium. It was possible to demonstrate that, even after loss of the mucus layer, adherence between the bacteria and the bronchial epithelium does not take place if ciliary function remains intact. Only after mechanical destruction of the bronchial epithelium, in proximity to squamous metaplasia or after loss or malfunction of the cilia of the bronchial epithelial cells was adhesion between bacteria and bronchial epithelial cells or basement membrane demonstrated by electron microscopy. After loss of the cilia following adenovirus-infection, adhesion betweenP. aeruginosa and the bronchial epithelial cells was visible. These results indicate that ciliary function must be of crucial significance in bacterial epithelial colonisation.

Morphological alterations to the bronchial mucosa in high-dosage long-term exposure to sulfur dioxide.

Light- and electron-microscopic studies were carried out on chronic bronchitis in the rat, produced by high-dosage long-term exposure to sulfur dioxide. Particular attention was given to the advanced stages of the disease. Inflammatory intramural infiltration and fibrosis developed in the regions of the bronchial tree near the hilus and in the peripheral sections. The highly differentiated cells of the bronchial epithelium perish at the same time. After a loss of the goblet and ciliate cells, extensive epithelial metaplasias with dysplasias develop in the central regions of the bronchus. Bronchiolitis obliterans develops in the peripheral regions of the bronchus. In the bronchiolar epithelium, the Clara cells, which play a crucial role in the maintenance of bronchial secretion in the advanced stages of the disease, are preserved.

p53 mutations and codon 213 polymorphism of p53 in lung cancers of former uranium miners

Purpose: There is a high prevalence of G→T transversions of p53 in lung cancers of smokers. One study has reported a special “hotspot” mutation at codon 249 of p53 in lung cancers of former uranium miners. The aim of our study was to look for mutational spectra of p53 in former German uranium miners with lung cancers. Methods: We investigated 16 patients with lung cancer who had worked as uranium miners in Germany and 13 lung cancer patients without a mining history of the same region. By means of the polymerase chain reaction and sequencing we looked for mutations in exons 5–7 of the p53 gene. Results: We could not find any suggestion of hotspot mutations. The only G→T mutation in former uranium miners was detected in the only nonsmoker. In 3 patients (19% of the total) we found a codon 213/3 polymorphism. Conclusions: The results indicate that G → T transversions do not seem to be very common mutations in p53 in lung cancers probably caused by radiation. Therefore, p53 may be mutated early in lung cancer development if radiation exposure is a critical factor in carcinogenesis. In accordance with studies of thyroid cancer patients in the Chernobyl region, our results may indicate an overrepresentation of codon 213/3 polymorphism in p53 in radiation-caused cancers.

MORPHOLOGICAL STUDIES OF THE RESPIRATORY SYNCYTIAL VIRUS INDUCED BRONCHIOLITIS IN EXPERIMENTALLY INFECTED CALVES

RSV-infections of the lower respiratory tract in infancy and early childhood are the most frequent causes of a hyperreactive bronchial system and obstructive lung disease. Studies concerning the morphological alterations of the bronchial mucosa during an RSV-infection are dependent on an experimental animal model. In this study the alterations of the lower respiratory tract from five infected colostrum-fed calves during the initial stage of the infection are described. BRSV strain 375 was applied as an aerosol on four consecutive days. The animals showed clinical symptoms already on the first day after infection. 7 days after the first infection the calves were necropsied. Lobular distributed atelectasis of the lung were found. The corresponding bronchioli were collapsed. The bronchiolar lumina were filled with a putrid exudate. In the bronchiolar wall a band-like lymphocytic infiltrate was found. By confocal laserscanning microscopy and by scanning electron microscopy intracellular viral components marked by an antibody against the viral P-protein were depicted. The intracellular virus inclusions were arranged along the bundles of filaments of the cytoskeleton. By transmission electron microscopy an alteration of the ciliogenesis and in cases of severe cell damage, cell death could be observed. The morphological findings suggest that the cytoskeleton plays an important role in the development of bronchiolitis.

The morphological substrate of autonomic regulation of the bronchial epithelium.

Observations of explanted bronchial mucosa show that ciliary function is maintained for 7 days subsequent to explantation. This finding demonstrates that non-neural mechanisms exist which regulate ciliary function. Ultrastructural and immunohistochemical studies both for light and electron microscopy were performed on human bronchial biopsy material and lung resection specimens in order to recognize the morphological substrate of this regulatory mechanism. A complex system of cytokeratin filaments and microtubules radiate through the whole cytoplasm of ciliated cells with direct contact to the nucleus, cilia, microvilli, desmosomes and to the apical terminal adhesive complex. Between the basal bodies and the apical terminal adhesive complex microfilaments can be found. In the apical cytoplasm a dense filamentary network is seen in association with the adhesive complex. These morphological findings indicate that the cytoskeleton of the bronchial epithelium plays a key role in the co-ordination of ciliary function.

The Role of Persisting Infections in the Pathogenesis of Pulmonary Emphysema: Electron Microscopy Reveals a Probable Bacterial Colonization of the Alveolar Space and the Bronchioles

Lung volume reduction surgery (LVRS) yields resection specimens from patients with advanced pulmonary emphysema. Regarding the development of lung function parameters, recent results obtained by light microscopy revealed an unfavorable prognosis in patients with remarkable inflammation, particularly in the bronchioli. Tissue from ten patients (alpha1-antitrypsin level in the normal range) was furthermore investigated by electron microscopy. Scanning electron microscopy shows 0.4-0.6 micron spherical bodies variably densely arranged in the whole alveolar space and in the bronchioles of all patients. These bodies are mostly seen on the microvilli of type II pneumocytes. An immunological reaction with activation of macrophages and granulocytes occurs simultaneously. Macrophages show cytoplasmic extensions to the spherical bodies, which exhibit a cellular membrane but no cellular wall. This favors the diagnosis of bacterial colonization of the alveolar space and the bronchioles by mycoplasmas or L-forms of other bacteria. As patients undergoing lung volume reduction surgery are under optimal medical treatment and without any infection clinically, these findings appear to be relevant for the pathogenesis and/or progression of pulmonary emphysema.

Vergleichende Untersuchungen an Konkrementen der menschlichen Niere mit dem Rasterelektronenmikroskop

The scanning electron microscope “Stereoscan” yields new results of the stereo-ultrastructure of crystalline deposits in the human kidney in diseases as oxalosis, gout, uric acid infarcts of newborns and calcification. The method seems particularly suited for the examining of the different morphological characteristics of crystals. Mit dem Rasterelektronenmikroskop „Stereoscan“ konnten Kristallablagerungen in der menschlichen Niere bei Oxalose, Gicht, Harnsäureinfarkten des Neugeborenen und Verkalkungen nachgewiesen werden. Mit dieser Methode ist es möglich, im sublichtmikroskopischen Bereich die morphologischen Unterschiede bei den verschiedenen Kristallisationsformen herauszustellen und gegeneinander abzugrenzen.