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Biomedical subjects

A Burkhardt

Publications and source records attributed to A Burkhardt.

At least 55 records · Page 3Linked to original sources
PubMed1986

[Verrucous carcinoma and carcinoma cuniculatum--forms of squamous cell carcinoma?].

The morphology of verrucous carcinoma (Ackerman tumor) and carcinoma cuniculatum is described and the problems of diagnosis and classification are discussed on the basis of the relevant literature. Both lesions are closely related aggressive proliferations of squamous epithelium of the skin and mucous membranes. Verrucous carcinoma exhibits an exophytic as well as endophytic growth pattern on a broad front; dissociated invasive growth, however, is usually absent. Carcinoma cuniculatum is similar; however, conspicuous deep duct-like formations and keratin-filled sinuses are formed. Clinically, these tumors appear to be malignant. Histological evaluation often results in the tumors being underestimated and a false diagnosis of a benign papillomatous lesion or pseudoepitheliomatous hyperplasia being made. The necessity is stressed of a thorough histological investigation of the tumors in multiple sections and of a search for dissociated invasive growth. It is suggested that cases without this feature should not be termed carcinoma but should rather be given a more descriptive diagnosis such as verrucous hyperplasia or proliferation. Cases with clear invasive growth should be classified as papillary squamous cell carcinomas (grade I). A detailed characterization should be given in addition. Although both tumors show features of viral lesions, it has so far not been possible to demonstrate viruses by electron microscopy or structural antigens of human papilloma viruses (HPV). Both clinical picture and histology must be taken into consideration when diagnosing these two tumors ("clinicopathologic entity"). Close cooperation between the clinician and the pathologist is desirable for individual assessment of these lesions as regards classification and therapy.

Carcinoma, Papillary↗
PubMed1982

Minor role of lipid peroxidation in acute bleomycin toxicity in rats.

Bleomycin was injected i.p. in rats, and the amount of expired ethane which indicates lipid peroxidation was followed up for 78 h. Compared to controls neither 1 x 30 mg/kg and 2 x 30 mg/kg nor 1 x 70 mg/kg bleomycin led to increased ethane expiration, although body weight loss indicated toxicity. That pulmonary toxicity had been developed due to the acute bleomycin treatment could be demonstrated by histological examinations of lungs of the animals of the highest dosage group. The combined treatment of rats with bleomycin and ferrous ions neither resulted in an increase of ethane expired compared to that of the ferrous ion-treated animals. Rather a decrease was observed. Our results indicate that acute bleomycin toxicity is not associated with increased lipid peroxidation. Furthermore, our data suggest that the bleomycin-ferrous-complex does not initiate lipid peroxidation in vivo.

Animals↗
PubMed1982

Dyskeratosis in human and experimental oral precancer and cancer. An immunohistochemical and ultrastructural study in men, mice and rats.

Dyskeratotic cells were examined with light and electron microscopy in human oral leukoplakias and carcinomas and in chemically-induced oral premalignant and malignant lesions of mice and rats. Specific antisera against small and large keratins were used to analyse the distribution of keratin polypeptides. In normal oral mucosa, basal cells did not react with antibodies against large keratins in contrast to the suprabasal cells which did react. Small keratins were found in all epithelial cell layers. In human and experimental premalignant and malignant lesions, intensely labelled dyskeratotic cells were seen, which contained small and large keratins regardless of their position in the epithelium. At the ultrastructural level, these cells showed dense aggregates of tonofilaments. Dyskeratotic cells were often seen in advanced stages of degeneration of phagocytosis of these cells by macrophages and giant cells was frequent. The disturbance of the keratinization process in oral precancer and cancer is easily visualized using keratin antisera. Keratin analysis can give new insights in epithelial maturation and may be helpful for the classification of oral leukoplakia.

Animals↗
PubMed1981

Multiple pulmonary (hamartomatous?) leiomyomas. Light and electron microscopic study.

The light and electron microscopical features of the lung tumors in a case of multiple pulmonary leiomyomas are described. The differential diagnosis of leiomyomatous tumors of the lung is discussed. They have to be differentiated from lymphangio-leiomyomatosis of the lungs. In the literature, multiple pulmonary leiomyomas are generally considered to be metastases from low grade uterine leiomyosarcoma or to be hamartomatous lung tumors. This is suggested by the glandular structures both within the tumor and on the surface. However, our ultrastructural observations showed these epithelia to have features of granular pneumocytes (type II), in particular they contain lamellar bodies and possess microvilli on their surface. Their formation is considered to be a secondary reaction of alveolar lining cells to tumor growth. A possible origin of multiple pulmonary leiomyomas from the contractile system of the lung acini (contractile interstitial cells) is discussed.

Female↗
PubMed1981

Epithelial and interepithelial mitoses of the oral mucosa: light and electron microscopic study in mice after exposure to different antigens.

Many epithelia respond to exogenous injurious agents with an increased proliferation. Until now interepithelial cells (neuroectodermal cells, lymphocytes, cerebriform cells and Langerhans cells) have been neglected in investigations of the proliferation kinetics of stratified squamous epithelia. In mice with different antigenic exposure, and in T-cell deficient nude mice mitoses in the oral epithelium were counted by light microscopy and the proportion of mitoses of interepithelial cells was determined by an additional ultrastructural analysis. NMRI mice raised in "germ-free" and "specific pathogen-free" environments exhibit decreased mitotic rates in lingual and buccal epithelia (16 mitoses per 1000 basal cells) when compared with mice raised in "normal" environments. NMRI mice exposed orally to Candida albicans exhibit increased mitotic rates in the same 2 epithelial sites (35 mitoses per 1000 basal cells after 2 days). Similar changes occur in athymic nude mice. The electron microscopic observations showed that most of the mitoses occurred among keratinocytes. Only sporadic mitoses of nonepithelial cells could be observed within the epithelium. However, these amounted to less than 5% of the total of mitoses. Our results show that for proliferation kinetic studies of squamous epithelia this low proportion of interepithelial mitoses may be negligible. Interepithelial cells apparently recruit mainly from migrating cells into the epithelium, while proliferation in situ plays a secondary role. As there are no signs of a transmigration of the epithelium by interepithelial cells they must be considered a recirculating cell population.

Animals↗
PubMed1980

["Hair-spray lung". Clinical and morphological findings].

We present two cases of an uncommon lung disease. The considerable decrease in respiratory function was in sharp contrast with the moderate changes seen in the lung. Whereas the radiographs only revealed a milky and a slightly reticular cloudiness of the lungs, pulmonary vital capacity and compliance were reduced to one half of the standard value. Open lung biopsies were performed. Histological examination showed a fibrosing alveolitis with considerable response and foreign body reaction of the alveolar and interstitial macrophages. Intraalveolar and interstitial granulomas included macrophages and multinucleated giant cells of the foreign body type. They frequently enclosed PAS-positive material. Ultrastructural examination revealed distinct lysosomal inclusions in the macrophages and giant cells. Similar inclusions were induced in guinea pigs by hair-spray components. These findings led to the diagnosis of an exogenous thesaurosis of the lung. Prolonged and excessive exposure to hair-sprays could be established in both cases. Upon termination of the exposure, a marked improvement occurred in both patients within half a year. Extreme exposure to hair-spray may cause alterations of the lung parenchyma, including a so-called "hair-spray lung". The present report is directed towards a better understanding of this particular disease which is one of the numberous conditions induced by the increasing air pollution.

Female↗
PubMed1980

Interepithelial cells of the oral mucosa. Light and electron microscopic observations in germfree, specific pathogen-free and conventionalized mice.

Interepithelial cells are found in all epithelia of the internal and external surfaces of the mammalian body. The regional differences of these interepithelial cells and their function are not completely known so far. The quantitative and qualitative changes of the interepithelial cell population were investigated in germfree, specific pathogen-free and conventionalized mice by light and electron microscopy. Germfree and specific pathogen-free animals did not show significant differences in the number of interepithelial cells. In the epithelium of the tongue a mean of 7.4 cells per 1000 basal cells is found. After conventionalization a significant increase to 14.4 interepithelial cells per 1000 basal cells is observed. The number of cells in the buccal epithelium is constantly about 20% higher than in the epithelium of the tongue. In the oral mucosa lymphocytes, cerebriform cells and Langerhans cells are an integral component of the epithelium. In contrast to the monostratified intestinal mucosal epithelium, which is considered a secondary lymphatic tissue, the interepithelial lymphocytes of the oral mucosa are not significantly decreased in germfree animals. This could indicate that the oral mucosa functions partly as a primary lymphatic tissue. Interepithelial cerebriform cells and Langerhans cells increased after conventionalization with a maximum after 10 days in response to exogenous antigens. Both cells are immunologically important. The observations prove that the oral mucosa represents a local immunologic system in which the Langerhans cells plays an important part by formation a reticulo-epithelial tissue.

Animals↗
PubMed1979

Alveolitis due to hair-spray. Ultrastructural observations in two patients and the results of experimental investigations.

Observation of two patients with hair-spray induced lung disease have prompted us to study the ultrastructure of the lung lesion. We have compared the results with experimental lesions in animals injected with hair-spray extracts and with human monocyte cell cultures exposed to hair-spray. The lungs show a chronic alveolitis with a striking granulomatous reaction including macrophages and multinucleated giant cells of the foreign body type. The intraalveolar and interstitial macrophages and the giant cells all contain PAS-positive material. Ultrastructurally distinct lamellar inclusions are found in the secondary lysosomes of the macrophages and giant cells. Identical structures can be produced in animals injected with hair-spray extracts and with polyvinyl-pyrrolidone and -acetate (PVP/PVA), which are regular ingredients of hair-sprays. Large, presumeably polymeric particles (PVP/PVA) are ingested by giant cells. This "gigantophagocytosis" is associated with the fusion of mononuclear phagocytes and leads to the genesis of giant cells. In cell cultures of human blood monocytes hair-spray extracts and PVP/PVA induce maturation and aggregation of these cells, with PAS-positive cytoplasmatic inclusions. The development of multinuclear giant cells in these monocyte cell cultures is also seen. These observations suggest that hair-spray induced lung disease is caused by the prolonged and extensive body response of the local mononuclear phagocyte system (MPS). Overstimulation of the MPS leads to a quantitative and qualitative change which is followed by a partial blockade of this system. The alveolitis is a consequence of the foreign body response to inhaled hair-spray substances.

Female↗
PubMed1979

Plasma cells and immunoglobulin-synthesis in oral precancer and cancer. Correlation with dysplasia, cancer differentiation, radio- and chemotherapy.

The subepithelial and peritumoral inflammatory infiltrates of 202 oral premalignant and malignant lesions -- 108 leukoplakias and 94 squamous cell carcinomata with different grades of dysplasia were examined using an immunoenzymatic method. In addition, the influence of radiation and bleomycin-therapy on the stromal reaction of 24 carcinomata was studied. The incidence of immunoglobulin labelled plasma cells (IgA and IgG) was twice as high in those cases of leukoplakia where dysplasia was present. The number of plasma cells, especially IgA- and IgG-containing plasma cells, decreased significantly with progressive tumor dedifferentiation. The plasma cell response differed before and after radiation with a decrease in IgA- and IgG-containing plasma cells after therapy. In contrast, bleomycin-therapy did not produce distinct changes in the humoral and cellular stromal reaction. In the epithelium, IgA and IgG were localized throughout all epithelial layers in leukoplakias with dysplasia. This finding indicates a leakage of locally synthesized immunoglobulins through an altered oral mucosa. This investigation reveals alterations in the local immune homoeostasis of the oral mucosa in premalignant and malignant lesions which varies with the grade of dysplasia, tumor differentiation and therapy.

Bleomycin↗