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K Wayss

Publications and source records attributed to K Wayss.

80 records · Page 5Linked to original sources
PubMedDate not supplied

Tumour induction in the rodent Mastomys natalensis by activation of endogenous papilloma virus genomes.

Specific DNA sequences from human papillomavirus have recently been detected in carcinomas from epidermodysplasia verruciformis patients, and in vulvar and cervical carcinomas but the role of papilloma viruses in the aetiology of these tumours is unclear. Indeed, little is known about the mechanisms that convert benign papillomas into malignant tumours and it is not even possible in tumour induction. Here, we describe an animal system that permits an analysis of the interaction of papilloma virus genomes with carcinogenic agents at the molecular level. In our colony of Mastomys natalensis (a close relative of the rat family), we have found extrachromosomal papilloma virus genomes persisting in a variety of tissues such as skin, muscle, liver and colon. With the ageing of the animals, the average copy number of viral DNA in skin cells increases and virus-producing tumours begin to appear in Mastomys at about 1 year old. This process is drastically enhanced by chronic treatment with a tumour promoter and transcription of the viral genomes has been found to be correlated with tumour formation.

Age Factors↗
PubMedDate not supplied

Radioactive labelling of lipids in rat neurosarcoma by intravenous injection of [1-14C]-octadecenol.

Radioactivity from cis-9-[1-14C]octadecenol, injected intravenously into rats bearing neurosarcoma, is incorporated to a significantly greater extent into tumor than into muscle. In the lipids of both tissues, radioactivity is incorporated predominantly into the acyl moieties, rather than into the alkyl or alk-1-enyl moieties, of diradylglycerophosphocholines, diradylglycerophosphoethanolamines, and triradylglycerols.

Animals↗
PubMedDate not supplied

Specific positional distribution of acyl moieties in phospholipids is not generally deleted in neoplastic cells.

The distribution of acyl moieties at sn-1 and sn-2 positions of cholinphosphoglycerides (CPG) and ethanolaminephosphoglycerides (EPG) has been determined for neurosarcoma, sarcoma 180 and leukemia L 1210. In all the three samples, the positional distribution of acyl moieties in the two major classes of phospholipids is found to be similar to that in cellular phospholipids of most mammalian tissues. The saturated acyl moieties are located predominantly at sn-1 and polyunsaturated acyl moieties at sn-2, whereas the monounsaturated acyl moieties are randomly distributed between these two positions. Apparently, a disruption of specific positioning of acyl moieties in phospholipids, which hitherto has been considered to be a general metabolic deletion in neoplasia, does not exist in an all neoplastic cells.

Acylation↗
PubMedDate not supplied

Sensitivity of human non-small cell lung cancer xenografts to cyclophosphamide and cisplatin.

In order to establish the usefulness of the nude-mouse human tumour xenograft system as a predictive screen for antineoplastic agents, the antitumour activity of cyclophosphamide (CTX) and cisplatin (DDP), two clinically active drugs, was tested against a panel of 14 human non-small cell lung tumour xenografts and the experimental results were compared with the clinical results reported in the literature. The poor clinical response of non-small cell tumours was reflected in the lack of response of the xenograft tumours to these two agents.

Animals↗
PubMedDate not supplied

Relevance of DNA-fluorimetry and short-term resistance testing for adjuvant treatment of non-small cell lung carcinomas.

In a clinical study 127 patients with previously untreated stage III non-small cell lung carcinomas (NSCLC) were investigated using flow cytometry and an in vitro short-term test for predicting resistance to cytostatic agents. Patients with aneuploid tumors and tumors with high proliferative activity had significantly shorter survival times than those with diploid or low proliferating tumors. The aim of this study was to find out whether groups of patients classified according to the additionally observed prognostic factors, experience an advantage or disadvantage from particular modalities of treatment. Seventy-nine patients had surgery alone, 18 patients were treated additionally with chemotherapy, and 30 patients with radiation. Patients with aneuploid, low proliferating and in vitro resistant tumors showed no different survival rates after treatment with chemo- and radiotherapy adjuvant to surgery. In contrast, patients with high proliferating tumors died earlier under adjuvant chemotherapy and radiation. Patients with in vitro chemosensitive tumors had shorter survival times after irradiation than patients who had surgery alone or who were treated with adjuvant chemotherapy.

Adult↗
PubMedDate not supplied

Flow cytometric analysis of primary lung carcinomas and their lymph node metastases.

Specimens of primary lung carcinomas and lymph node metastases from the same 18 patients were investigated by means of flow cytometry. The number of DNA stemlines, DNA indices, the proportion of diploid cells in the tumors and the distribution of the cell cycle phases were compared. In 10 patients DNA stemlines and DNA indices were identical in primary tumors and metastases. In two cases the DNA indices were doubled in metastases. In 6 cases the primary tumors contained two abnormal DNA stemlines and their metastases contained only one aneuploid stemline. Gross differences between primary tumors and lymph node metastases with regard to the proportion of cell cycle phases could not be found. The large variation between primary tumors and lymph node metastases with regard to DNA stemlines indicates that flow cytometric analysis of lymph nodes gives only limited information about the primary tumors.

Adenocarcinoma↗
PubMedDate not supplied

Therapeutic response of human lung tumour xenografts to cyclophosphamide.

The effect of cyclophosphamide, given as a single i.p. injection (240 mg/kg) on 13 various fast growing human lung tumours, transplanted and passed serially in athymic nude mice, were studied. Cyclophosphamide showed activity against all tumours studied. The sensitivity of the different tumour lines tested varied considerably. The faster a tumor was growing, the more pronounced was the inhibitory effect of cyclophosphamide on growth, independent of the histological type. If different lung tumours were treated at the same size and site (8-10 mm, s.c. right anterior flank), growth rate was a factor of decisive importance for the sensitivity of a tumour to cyclophosphamide.

Animals↗