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Biomedical subjects

J Althoff

Publications and source records attributed to J Althoff.

At least 19 recordsLinked to original sources
PubMed1991

Effects of age and gender on fat-induced gallbladder contraction and gastric emptying of a caloric liquid meal: a sonographic study.

In this study, the gastric emptying of a liquid fatty meal and the consecutive gallbladder contraction were simultaneously measured by ultrasound in four different age- and sex-related groups of normal subjects: group A, 15 women less than 50 yr (premenopausal); group B, 15 women greater than 50 yr (postmenopausal); group C, 15 men less than 50 yr; and group D, 15 men greater than 50 yr. Apart from a significantly delayed gastric emptying in the premenopausal women, no significant differences in the postprandial relative gallbladder emptying rates were observed between the four study groups. Ninety-five percent of all study subjects had a gallbladder volume reduction of more than 50% after a liquid fatty meal. It is therefore concluded, that 1) endogenous or contraceptive female sex hormones may have a delaying effect on gastric emptying of caloric liquids in the premenopausal state, 2) aging or gender do not significantly influence the fat-induced gallbladder contraction in man, and 3) a 50% residual volume of the gallbladder after a fatty meal should be considered as the upper limit of normal gallbladder contractility (95 percentile of a normal collective).

Adult↗
PubMed1986

Cemento-fibrous dysplasia of the periodontal membrane (studies of the European hamster maxillary incisor).

The periodontal membrane of European hamster maxillary incisors showed histologic changes consisting of an irregularly orientated, less vascularized connective tissue which included abundant cementicle-like structures. The changes were multifocal and bilateral, growing towards the alveolar bone (Grade 1), causing atrophy of the alveolar bone due to compression (Grade 2) and reaching the periosteal membranes (Grade 3). In a few animals, the lesions were seen after one year. They were seen in 80% of hamsters more than 2 years old. Carcinogenic exposure did not alter the latency and incidence of the alterations. The lesions were thought to be a spontaneously occurring disease representing a nodular cemento-fibrous dysplasia of the periodontium. As, morphologically, no exact attribution to other odontogenic or mesenchymal growth could be made, the entity of this periodontal lesion was considered. Although the changes observed in the periodontal membrane of the maxillary incisors of the European hamster were not exactly comparable to odontogenic cemental lesions in man, they may serve as a model to further clarify the nature of fibro-osseous lesions.

Alveolar Process↗
PubMed1985

Comparative study on the carcinogenicity of N-nitroso-2,6-dimethylmorpholine in the European hamster.

The effect of N-nitroso-2,6-dimethylmorpholine (NDMM), a pancreatic carcinogen for the Syrian golden hamster, was examined in the European hamster (EH) for comparative reasons. The compound was administered by subcutaneous (SC) injection or intragastric gavage (IG) at a dose level corresponding to 0.1 of LD50. In terms of carcinogenicity the main target was the respiratory epithelium (nasal cavity, lung, trachea, larynx); other benign and malignant tumors originated in the liver (bile duct epithelium and endothelium) and renal pelvis (transitional epithelium). The occurrence of neoplasms seen at other sites was difficult to attribute to treatment. Reduced metabolism as found during hibernation did not change the organ distribution of neoplastic growths. Differences in the carcinogenic potency (tumor incidence and latency, affected organs and cell types) did not depend significantly on the route of administration. The data were compared to those obtained using other nitroso compounds in this species.

Animals↗
PubMed1985

The influence of metabolic liver defects on diethylnitrosamine (NDEA)-carcinogenesis in Gunn rats.

Diethylnitrosamine (NDEA) was administered subcutaneously to non-icteric and icteric Gunn rats. A single dose led predominantly to liver cell tumours. The average survival times and tumour latencies were not dose dependent, but a slightly raised tumour multiplicity was observed in icteric animals. The minimal effective dose was apparently less than 0.05 LD50 and more than 0.025 LD50. Chronic treatment in Gunn rats revealed dose response relationships for body weight development, average survival times and tumour latencies. The most common tumours found in the liver of both non-icteric and icteric animals were hepatocellular neoplasms followed by cholangiocellular tumours and haemangio-endotheliomas. Neoplastic growth was also found in the respiratory tract and upper digestive tract. The maximal effective carcinogenic dose for non-icteric and icteric rats was 0.1 LD50. The carcinogenic effect of NDEA in Gunn rats was only marginally influenced by the changes in the liver associated with icterus.

Adenoma↗
PubMed1985

Ultrastructural aspects of oral and facial lepromatous lesions.

The ultrastructure of 10 lepromatous lesions in the face and the palatal mucosa after different duration and length of treatment was studied. Biopsies taken from patients who showed erythema nodosum leprosum (ENL) revealed different ultrastructural characteristics from those taken from 'burnt out' and non-medicated cases. Multiple secondary lysosomes were rarely seen in non-ENL cases. The presence of Mycobacterium leprae and an increased lysosomal activity in ENL reactive cases is interpreted as a reaction to the lysis of the cytoplasmic matrix of M. leprae; however, drug-specific (diaminodiphenylsulphone) reactions must also be considered.

Adolescent↗
PubMed1985

Biological characterization of human bone tumors. IV. Combined biochemical and histological analyses of different osteosarcomas.

A new technique was applied to the study of human osteosarcoma. Ten slices of 10 micron were cut serially from 2 X 2 X 6 mm shock frozen blocks of human osteosarcoma for chemical analysis. Before and after each series of 10 slices, one slice of 10 micron was separated for morphological analysis. Four different types of osteosarcoma were investigated: Case 1 was an atypical osteoblastic osteosarcoma, case 2 a small cell sclerosing osteosarcoma, case 3 a well-differentiated parosteal osteosarcoma grade I, and case 4 a highly malignant anaplastic osteosarcoma. Alkaline phosphatase, acid phosphatase, beta-glucuronidase and proteolytic activities were analysed as well as matrix collagen and hexosamine, phosphorus (Pi and Po), protein, DNA, and water content. In accordance with the morphology, the obtained data illustrate the great heterogeneity of osteosarcomas. Although case 1, 2 and 3 all represent calcifying types of the tumor, characteristic differences exist with regard to the matrix and the degree of calcification. In contrast to these three, case 4 presents a noncalcified type of osteosarcoma whose matrix contains relatively high amounts of hexosamine and low amounts of collagen, whereas DNA and water contents are high. The data from the analysis of osteosarcoma were compared with previous results from the calf epiphyseal growth plate in order to define differences and similarities between the formation of tumor bone and the physiological formation of hard tissue.

Acid Phosphatase↗
PubMed1985

Biological characterization of human bone tumors. V. Zonal characterization of osteosarcoma: topological biochemical analysis correlated with morphology.

Human osteosarcoma specimens were sliced in a cryomicrotome under strict morphological guidance. Serial sections of ten 10 micron slices each were collected in two groups according to morphologic criteria, one containing mostly undifferentiated tumor tissue, the other predominantly well-differentiated tumor tissue. The two series were analysed chemically for alkaline phosphatase (APase) acid phosphatase (acPase), beta-glucuronidase and proteolytic activities; protein, phosphorus, hydroxyproline, hexosamine, water and collagen contents were also determined. Four different types of osteosarcoma were studied: case 1 was a highly malignant osteoblastic osteosarcoma, case 2 a small cell sclerosing osteosarcoma case 3 a well-differentiated osteosarcoma, and case 4 a highly malignant anaplastic osteosarcoma. The types of cases 1, 2 and 3 are known as osteoid-forming tumors. In their less well differentiated areas APase activity was about twice as high as in better differentiated osteosarcoma. In contrast, no APase was found in the wholly undifferentiated areas of case 4, while the enzyme showed a marked increase in the areas of incipient differentiation of this tumor. The matrix of tumors differs with regard to collagen and hexosamine contents, in accordance with the general state of differentiation. In general, increasing hexosamine contents together with decreasing hydroxyproline contents will reflect the anaplastic, dedifferentiated osteosarcoma. Calcification evident in the better differentiated areas of osteosarcoma is indicated by the phosphorus content, highest in case 2, with cases 3, 1, and 4 following in sequential order.

Acid Phosphatase↗
PubMed1985

Carcinogenicity of diallylnitrosamine following intragastric administration to Syrian hamsters.

Single and multiple intragastric doses of diallylnitrosamine [(DAN) CAS: 16338-97-9] administered to Syrian golden hamsters induced tumors, primarily of the respiratory tract, in which the nasal cavity epithelium was the preferred site. When compared to the effect of DAN after subcutaneous administration at equal doses, the incidence of respiratory tract tumors was lower but that of hepatic tumors was higher, suggesting partial metabolism of DAN in the liver. Comparative metabolic and mutagenesis studies in BD IX rats (which reportedly are refractory to the carcinogenic effects of DAN), in Wistar rats, and in Syrian hamsters showed that a greater proportion of orally administered DAN was exhaled by both rat strains (12-19%) than by hamsters (2-4%). The activity of the microsomal fraction of the hamster liver for metabolizing DAN to allyl alcohol was about 10 times higher than that in rats, whereas no significant species differences were found with the cytosolic fraction. Pretreatment of animals with phenobarbital (PB) or pregnenolone-16 alpha-carbonitrile (PCN) did not influence either microsomal or cytosolic enzyme activities in hamsters, whereas about a tenfold increase in enzyme activities was seen after pretreatment with PB in both rat strains and following PCN in Wistar rats. Moreover, in bacterial mutagenesis assays, hamster liver microsomes were twice as active as those in BD IX rats. The results are discussed in relation to the carcinogenicity of DAN in rats and hamsters.

Adenocarcinoma↗
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↗
PubMed1979

Comparative studies of neoplastic response to a single dose of nitroso compounds. 6. The effect of diethylnitrosamine in Syrian golden hamsters.

The effect of a single subcutaneous injection of different DEN doses was examined in adult Syrian hamsters observed for life. The minimal effective dose (threshold dose) for neoplastic response, reflected by induction of papillary polyps in the larynx and/or trachea, was 1.03 mg DEN/kg body weight. No tumors were found which could be related to treatment in other segments of the respiratory epithelium nor in other tissues.

Animals↗
PubMed1979

Implantation of cigarette smoke condensate in the lungs of Syrian golden hamsters.

Different doses of benzo(a)pyrene, cigarette smoke condensate (CSC) and its nitromethane fraction (NMF), in wax pellets, were directly implanted into the lungs of Syrian golden hamsters. Pleomorphic sarcomas were induced in the B(a)P treated animals. Several epithelial proliferative lesions and a few bronchiogenic adenomas were induced in CSC and NMF treated hamsters. A species-specific effect has been observed in this investigation.

Adenoma↗
PubMed1979

Study of Biopsies from lesions of the oral mucosa by scanning electron microscopy (S.E.M.).

Surface epithelial cells from 55 biopsies including lichen planus, leukoplakia and squamous cell carcinoma were studied by scanning electron microscopy. The surface structures of the various oral lesions demonstrated morphological differences. After more information has been collected, the method of SEM may be of value for the recognition of pre- and early neoplastic lesions in the oral cavity.

Biopsy↗
PubMed1979

Spontaneous tumors and common diseases in three types of hamsters.

Hamsters of three types designated as inbred cream (Epp/e/e), linebred white (EPP/cdcd/RB/A), and linebred albino (EPP/cdcde/e) were thoroughly examined histopathologically for spontaneous diseases. All hamsters were maintained simultaneously for life under identical standard laboratory conditions. Marked differences were found in longevity of the animals and in incidence, sites, patterns, and types of spontaneous diseases. In cream hamsters (CH), survival time was shorter than in white hamsters (WH) and albino hamsters (AH). More tumors and malignant lesions unrelated to survival were found in AH compared to CH and WH; also, the multiplicity of neoplasms were more pronounced in AH. The predominating tumor types differed in each line: Pancreatic islet cell neoplasms were most common in CH, adrenal gland tumors predominated in WH, and thyroid gland tumors in AH. Also, the relative incidence of spontaneous tumors varied among the lines. Some tumors seemed strain-specific and were not seen in other lines; malignant melanomas, for example, occurred only in CH and WH. Certain neoplasms, e.g., those of the thyroid and adrenal glands, were found more often in one sex than the other. The three hamster groups differed also in nonneoplastic diseases. Detailed histopathologic findings are presented and compared with data on the Syrian golden hamster, the ancestral line of these three groups.

Amyloidosis↗
PubMed1979

224 Ra and 226Ra experimentally induced dental changes in rats.

Sprague-Dawley rats received intragastrically a single dose of 226Ra or 224Ra once weekly for 21 weeks. During this period the animals of both groups were thus exposed to comparable doses. After 12 weeks, a shortening of the maxillary incisors was observed, and this progressed during the course of the 55-week experiment. Radiologically, a loss of pulpal transparency and an apical irregular opacity in the maxillary incisors were demonstrable. Histologically, dysplastic changes of the maxillary incisors and multiple resorptions at the cemento-enamel junction of the molars were seen. The observed alterations were more pronounced in the 226Ra group than in the 224Ra treated group. The experimentally induced resorptions were comparable to those observed in patients who had incorporated 224Ra or 226Ra. Clinical, radiological, histological, gamma-spectrometrical, and autoradiographical findings, as well as dose-estimations, are described.

Animals↗