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Biomedical subjects

J Althoff

Publications and source records attributed to J Althoff.

At least 37 records · Page 2Linked to original sources
PubMed1985

Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golden hamster. VI. In vitro effects of different polycyclic aromatic hydrocarbons.

In a comparative study, the biological effects of different polycyclic aromatic hydrocarbons (PAH) on the fetal respiratory epithelium of Syrian golden hamsters were examined (light and scanning electron microscopy) in tracheal explants exposed in vitro to benz(a)anthracene (BaA), benz(a)acridine (BaAC), benzo(b)fluoranthene (BbF), benzo(e)pyrene (BeP), benzo(k)fluoranthene (BkF) and pyrene (PYR). Concentrations of the compounds related to the solubility in dimethylsulphoxide in the tissue culture medium (0.5% DMSO). Focally slight inhibition of epithelial differentiation and/or circumscribed simple metaplasia with an incidence of up to 10% were found in the controls (0.5% DMSO), BeP and PYR groups as well as in the explants exposed to low levels of BaA and BaAC. The frequency of these lesions increased with raising (doubling) the dose (50%: BaAC, BbF, BfK; 100%: BaA). Following exposure to the latter compounds a similar dose response relationship was observed for dysplastic alterations of the respiratory epithelium. In some of these cases (10%) the epithelial change was associated with focally hyperplastic and/or proliferative exophytic growth. Morphologically, the alterations were comparable to those representing early changes associated with the development of epidermoid and mucoepidermoid neoplasms found after in vivo PAH exposure. In terms of transformation, the data support the information obtained from observations on mixed fetal hamster lung cells exposed to the same compounds.

Animals↗
PubMed1984

The influence of caffeine on tumour incidence in Sprague-Dawley rats.

Food-grade natural caffeine was given in the drinking-water (available ad lib.) to barrier-maintained specified-pathogen free Sprague-Dawley rats for 2 yr. Groups of 50 animals per sex received levels of 200, 430, 930 and 2000 mg caffeine/litre, while two control groups, each of 50 animals per sex, received plain water. No unusual tumours or sites of origin for neoplastic growth were found in any animal receiving caffeine. Neoplasms found in various organs showed incidences not exceeding those seen in controls. Thus, exposure to caffeine for 2 yr did not enhance or induce neoplasia in the Sprague-Dawley rats.

Animals↗
PubMed1983

Carcinogenic effect of nitrosomorpholine administered in the drinking water to Syrian golden hamsters.

The long term carcinogenic effect of nitrosomorpholine (NM) was tested in Syrian golden hamsters (Mesocricetus auratus W.). Groups of 30 females and 30 males were given 0.010%, 0.005% and 0.001% NM in their drinking water. The animals developed neoplasms in the larynx, and trachea (papillary polyps, papillomas and epidermoid carcinomas) and in the liver (hepatocellular adenomas and carcinomas). In addition to these, cholangiocellular and endothelial liver tumours were observed. The overall tumour frequency was dose dependent.

Animals↗
PubMed1983

Oral leukoplakia: a scanning electron microscopic study of epithelial surface patterns.

Biopsies from oral leukoplakias of different anatomic locations were studied by light- and scanning electron microscopy. Clinically, 11 cases showed the homogenous, flat type, and 3 represented the inhomogenous, nodular type of oral leukoplakia. The surface patterns of lining epithelial cells, as well as the cut surface structures were compared with those obtained by light microscopy. The results were compared with other published findings of normal oral mucosa, oral leukoplakia, oral carcinoma, and lesions of the uterine cervical mucosa. The epithelial surface cells revealed micropatterns comparable to normal ortho- or parakeratotic cells in the cases of homogenous oral leukoplakia. Biopsies showing varying degrees of dysplasia revealed cell surfaces with irregular microvilli or swollen microridges; cell forms also showed varying profiles and shapes as well as pleomorphism. Cell desquamation was seen in all cases. Since cell maturation and differentiation is linked to a specific surface morphology, SEM has to be considered as a further valuable diagnostic method.

Adult↗
PubMed1983

Assessment of nitrosamine transplacental carcinogenesis in the Syrian golden hamster.

The effects of diethylnitrosamine (DEN) and vinylethylnitrosamine (VEN) in the F1 generation of Syrian golden hamsters are described after the compounds were administered to the P generation during the second half of pregnancy. Morphologic findings revealed that the upper respiratory tract (i.e., trachea) was most affected. VEN appeared highly effective because the first neoplastic alterations (papillary polyps) were seen in both the P and the F1 animals at the 30th postnatal day. The fetal tracheal epithelium also showed chromosomal aberrations after DEN exposure, and VEN enhanced the cloning efficiency of these cells. Combined in vivo - in vitro studies are discussed with special emphasis on the early detection of transformation and neoplastic growth.

Animals↗
PubMed1982

A fetal respiratory epithelial cell line for studying some problems of transplacental carcinogenesis in Syrian golden hamsters.

Using repeated cloning and treatment with cis-HPL (200 micrograms/ml), an analogue of a procollagen precursor inhibitory to the growth of collagen-synthesizing cells of mesenchymal origin, clonally premature epithelial cell lines were isolated from fetal SGH lungs cultured on the 15th day of gestation. One of the cell lines, M3E3/C3, which has been extensively studied for biological characterization, developed poorly differentiated carcinomas in injected hamsters after transformation by MNNG. Moreover, when grown on collagen gel, this cell line indicated an obvious potency for in vitro differentiation in response to vitamin A by developing activated Golgi regions, well developed rER and a number of mucus-like granules. Since such a differentiative responses is expected to be definable in the light of respiratory epithelium developing in utero, this cell line may be useful for studying mechanisms of differentiation-dependent sensitivity of fetal organs to transplacental carcinogen exposure.

Animals↗
PubMed1982

Carcinogenicity of vinylethylnitrosamine in Syrian golden hamsters.

Syrian golden hamsters received weekly s.c. doses of 5.0, 2.5, 1.25 or 0.63 mg/kg b.w. vinylethylnitrosamine (VEN). As dose levels increased, average survival time decreased, tumor multiplicity increased as did the total tumor rate which was between 50% and 100%. The main target of VEN effect was the respiratory tract where a positive dose-response relationship was established for neoplastic growth.

Animals↗
PubMed1982

Morphological studies on the epiphyseal growth plate combined with biochemical and X-ray microprobe analyses.

The epiphyseal growth plate of the domestic pig was investigated topologically combining biochemical methods with electron microprobe microanalyses both correlated to histological controls. A lateral resolution of about 50 micrometer was reached. Highest nuclease activity was found in the lower columnar cell zone, while alkaline phosphatase showed maximal activity in the hypertrophic area, connected with maximal values for extractable, organically bound phosphorus, and extractable Ca and Mg. Acid phosphatase activity reached maximal values in the zone of the lower primary spongiosa, while the extractable Pi had maximal values at the end of the zone of bone remodelling. Microprobe analyses have shown that the extracellular Ca content (per dry mass) remained relatively constant at 0.7% (about 58 mM/kg wet weight for 66% tissue fluid) in all zones of the plate increasing to 1% in the vicinity of the first foci of mineralization. The intracellular P content (per dry mass) was about 4.5 %, the extracellular 0.1-0.2% (about 10-20 mM/kg wet weight) increasing also to about 1% in the vicinity of the first foci of mineralization. Thus the Ca X P product was much higher than the ion-product of 2 mM2 which is necessary for an in vitro mineralization of connective tissue. The extracellular S content (per dry mass) as a probable indicator of sulfated proteoglycans was relatively constant at about 3.5% in the different zones but decreased to about 0.3% in the fully mineralized regions. This indicates a loss of sulfur containing substances with mineralization which is not so high since the concentrations per dry mass must be normalized to a unit volume of equal density of mass.

Alkaline Phosphatase↗
PubMed1982

[Bone healing and dynamic interferential current (DIC) (author's transl)].

The aim of this investigation was to clarify the influence of dynamic interferential current (DIC). Two sinusoidal currents of medium frequency are superimposed within the body to determine the reactive changes of bone healing after osteotomy. An osteotomy was performed on the radius and ulna of the right foreleg of 34 'black-head breeding sheep'. The radius shaft was deperiostalized and unstably fixed with a four-hole AO-plate leaving a gap of at least 1 mm width. DIC of different mA-values were not treated 24 sheep 3 times per week for 10 mins. The other 10 animals were not treated with DIC but used as control animals. The different results of our clinical, radiological, histological and chemical analyses to date indicate that callus formation is accelerated by the application of DIC. The fracture callus of treated animals is strongly mineralized.

Animals↗
PubMed1982

[Bone healing and dynamic interferential current (DIC) (author's transl)].

In the course of supplementary physical and chemical investigations of the influence of Dynamic Interferential Current (DIC) on bone healing 24 black-head sheep were subjected to transversal osteotomy of the radius. After an instable osteosynthesis the site was exposed to repeated therapy with DIC of varying mA intensity. (Methodological details are described in part I). DIC therapy resulted in altering the temperatures in the treated tissue, dependent on the mA intensity. Further associations were verified between DIC intensity and the occurrence of hydroxyprolin, and amino acid specific collagen, which also reflected increased calcifying activity. Measurement of the calcium and phosphorus levels in the regenerated (newly forming) bone tissue documented full mineralization in the DIC-treated animals at a much earlier date than in the untreated controls that had undergone similar operations. Whether DIC specifically stimulates osteogenesis within "healing" bones is still unclear.

Alkaline Phosphatase↗
PubMed1982

Granular type of denture stomatitis. A scanning electron microscopic study of epithelial surface patterns.

Biopsy specimens from the palates of patients with full upper dentures were studied by light, transmission, and scanning electron microscopy. Clinically, all cases showed the granular type of denture stomatitis (inflammatory papillary hyperplasia). The surface structure of the epithelium and the morphology of the connective tissue papillae in this hyperplastic lesion were examined and compared to the epithelial surface patterns of normal palatal mucosa. In addition, comparisons were made with the morphologic findings from the studies of other authors on epithelial dysplastic lesions (leukoplakia) and oral carcinoma. Specimens of denture stomatitis revealed a chronic inflammatory reaction and papillary patterns showing broad, irregular connective tissue papillae which supported a focally hyperplastic and partly atrophic surface epithelium. The epithelial surface cells showed slight desquamation, ledged cell borders and surface pitting and/or microridge formation. Maceration preparations revealed unusual, multitufted, connective tissue papillae.

Adult↗
PubMed1982

A chronic study of praziquantel in Syrian golden hamsters and Sprague-Dawley rats.

Groups of Syrian golden hamsters and Sprague-Dawley rats received 100 mg or 250 mg praziquantel/kg body weight, intragastrically by oral gavage once weekly for 80 weeks and 104 weeks, respectively. In both hamsters and rats the observed differences in tumour incidence, latency and multiplicity revealed no positive dose response effect. Tumours observed corresponded in their origin and morphology to those which develop spontaneously in these species. Haematological and clinico-chemical values were normal. Whereas the average survival time was slightly shortened in rats, female hamsters showed reduced weight gains in the high dose level groups, although water intake and food consumption were increased.

Animals↗
PubMed1982

Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golden hamster: transplacental effects of vinylethylnitrosamine.

The transplacental effect of vinylethylnitrosamine (VEN) on the respiratory epithelium of Syrian golden hamsters was tested after administration of 5 and 10 mg VEN/kg b.w. dissolved in olive oil at the 12th or 15th day of gestation. The morphological data, obtained mainly by scanning electron microscopy on tracheae revealed metaplastic and hyperplastic epithelial changes, as well as focal exophytic papillary proliferations at the 30th postnatal day in the group treated at the 15th day of gestation. No comparable lesions were found in the trachea of the F1 generation when mothers were treated with VEN at day 12 of pregnancy or in animals of the control group (olive oil only). The biological effects of VEN after transplacental exposure were compared to those of other nitrosamines.

Animals↗
PubMed1982

Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golden hamster. IV. In vitro effects of dimethylsulphoxide and benzo(a)pyrene.

The biological effects of in vitro exposure of cultured fetal hamster tracheal epithelium to benzo(a)pyrene in 0.5% dimethylsulphoxide (BaP: 5 and 10 micrograms/ml medium) were studied by light and scanning electron microscopy. The solvent, DMSO, alone induced a slight, temporary retardation in development and differentiation of cilia. At day 28 of culture, however, differences in growth and maturity disappeared between DMSO-exposed and untreated explants. No dose-related differences found in the surface morphology of alterations were seen in BaP-treated tracheae; the explants revealed metaplastic foci and reduced, incomplete ciliogenesis compared to DMSO- and non-treated controls. Towards the end of the culture period, ciliogenesis tended slowly to replace epithelial alterations.

Animals↗
PubMed1982

[Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golde4n hamster. V. Dose-related in vitro effects of benzo(a)pyrene].

The biological effects of in vitro exposure of fetal hamster tracheal explants to three dose levels of benzo(a)pyrene (BaP:25, 50, 100 microgram/ml medium) in 0.5% dimethylsulphoxide (DMSO) were studied by light and scanning electron microscopy. A dose-related difference was seen in a quality of the observed pathological alterations in the specimens examined after 28 days of culture. Whilst in the explants treated with 50 or 100 microgram/ml BaP the respiratory epithelium revealed necrotic areas and extended metaplastic alterations, explants exposed to 25 microgram/ml BaP showed normal differentiation in some areas of the respiratory epithelium. In explants treated with the highest dose (100 microgram/ml BaP), hyperplastic foci were seen in the epithelium and tended to proliferate towards the tracheal lumen. These observations show similarity with early neoplastic alterations.

Animals↗