Dehydroepiandrosterone causes hyperplasia and impairs regeneration in rat liver.

DHEA, a steroid of the adrenal gland, is a non-genotoxic hepatocarcinogen of the peroxisome proliferator type in rodents. However, DHEA also exerts anti-carcinogenic effects by reducing the number and proliferation of preneoplastic and neoplastic lesions induced by N-nitrosomorpholine. The mechanism underlying this growth-modulating effect is unclear, and no data are available on DHEA effects on normal liver.

Experimentally induced infection with autonomous parvoviruses, minute virus of mice and H-1, in the African multimammate mouse (Mastomys coucha).

To determine whether the multimammate mouse (Mastomys coucha) could be used to evaluate rodent parvovirus-based vectors, neonates were subcutaneously inoculated with minute virus of mice (prototype strain, MVMp) or rat parvovirus H-1. The course of infection with both viruses was similar. Seroconversion occurred within two weeks after virus inoculation, as detected by use of hemagglutination-inhibition assays, and antibody titers remained high for the entire observation period of 12 months.

[Angiogenesis of human breast cancers: neovascularization in xenotransplants and oxygenation in situ in patients].

Objective: Recent reports have shown that vascularization of breast cancers is an independent prognostic parameter. Tumor growth and neovascularization were investigated in xenotransplants of breast cancers and tissue oxygenation was measured in patients with breast tumors.

Methods: Tumor cells of the breast cancer MX-1 were implanted intradermally in 40 nude mice.

Activation of latent papillomavirus genomes by chronic mechanical irritation.

The skin of animals of a laboratory strain of Mastomys natalensis carrying endogenous, latent papillomavirus genomes was irritated by scratching with glasspaper. Hyperproliferation of the epidermis and amplification of viral DNA followed this treatment, and in approximately 27% of the animals virus-producing papillomas were induced.

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.

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.

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.

Prognostic significance of DNA patterns and resistance-predictive tests in non-small cell lung carcinoma.

In a cooperative study, 240 surgical specimens of patients with non-small cell lung carcinomas (NSCLC) were investigated by means of flow cytometry, xenotransplantation to athymic mice and, an in vitro short-term test for predicting resistance. Aneuploidy was found in 83% of the tumors, and 20% showed more than one aneuploid DNA stemline. Patients with both aneuploid tumors and tumors with more than one DNA stemline had a significantly shorter survival rate than those with only diploid or only one DNA stemline.

DNA distribution in non-small-cell lung carcinomas and its relationship to clinical behavior.

A study of 187 surgical specimens of tumors of patients with non-small-cell lung carcinomas was carried out by means of flow cytometry. Eighty-four percent of the tumors were classified as tumors with abnormal DNA stemlines (DNA aneuploidy). Patients with tumors demonstrating DNA aneuploidy had significantly shorter survival times than those with tumors demonstrating DNA diploidy (p = .

Growth of human bronchial carcinomas in nude mice.

Two hundred and thirteen lung tumours of primary site and 42 metastases were heterotransplanted into nude mice with an overall success rate of 44%. There were differences in success between the histological types. Squamous cell and adenocarcinoma had the highest success rate (51% and 43%, respectively) whereas large cell and small cell carcinoma had a lower success rate (38% for both).

Sequential methotrexate (MTX) and 5-fluorouracil (FU) in human tumor xenografts.

Human and animal tumor-lines heterotransplanted in nude mice were treated with MTX and FU sequentially. In order to investigate the relationship between tumor response and drug toxicity sequence, time and dose of both MTX and FU were varied. Pretreatment with MTX followed by FU with intervals of 3 or 24 h produced superior therapeutic results when compared to single administration of MTX or FU, simultaneous treatment, or the reverse sequence.

Effect of five antineoplastic agents on tumor xenografts with different growth rates.

The effects of cyclophosphamide (Cy), doxorubicin (Dx), cisplatin (DDP), melphalan (L-PAM), and vincristine (VCR) on various human and animal tumor lines with different growth rates, growing as xenografts in NMRI (nu/nu) mice, were studied. Two types of response were observed: For Cy and Dx, the response of the xenografts was negatively correlated with tumor volume doubling time (TD), indicating that rapidly growing tumors were more sensitive to these drugs than were slowly growing tumors. For DDP, L-PAM, and VCR, the effects were positively correlated with the TD, indicating that slowly growing tumors were more sensitive to these drugs than rapidly growing tumors.

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.

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.

Polysomal polyadenylated RNA and albumin messenger RNA in Mastomys liver and in a chemically induced hepatocellular carcinoma.

A hepatocellular carcinoma line (H78) was established from a primary liver tumor induced in Mastomys natalensis by a single administration of dimethylnitrosamine. Six to 8 months after transplantation (passages 5 to 7), well-differentiated tumors, still containing glucogen-storing cells, were isolated and used for the preparation of RNA. Polysomal polyadenylated RNAs from Mastomys liver and from H78 tumor line were then compared by hybridization kinetics.

Growth kinetics of human lung tumours in nude mice.

In order to investigate the growth characteristics of xenografts of human tumours in nude mice, we heterotransplanted 22 human tumours of the lung into nude mice. We noted growth in 11 of these tumours (50%). The histological appearance of most of the tumours growing in the first passage in nude mice was comparable with that of the donor tumours.

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.

Chemical carcinogenesis by the two-stage protocol in the skin Mastomys natalensis (Muridae) using topical initiation with 7,12-dimethylbenz(a)anthracene and topical promotion with 12-0-tetradecanoylphorbol-13-acetate.

The long-term (34 weeks) topical administration of 7,12-dimethylbenz(a)anthracene (DMBA) to the skin of male and female Mastomys induced a broad spectrum of benign and malignant tumors in all animals treated. In a two-stage carcinogenesis experiment with topical initiation with DMBA and topical promotion with TPA, 50% of the animals developed both benign and malignant skin tumors. In general, benign tumors occurred between weeks 15 and 25, whereas malignant tumors were seen 40 weeks after initiation.

Studies on the specificity of tissue supernatants on the proliferation of liver in baby-rats.

Supernatants (105,000 g) prepared from extracts of liver and kidney were injected at different concentrations into 10 day-old rats and the resulting effects on 3H-thymidine incorporation in liver, kidney and lung were measured over a period of 24 hours. Incorporation in all three organs is inhibited by supernatants from both liver and kidney, with maximal activity between 12 and 18 hours after injection. Fractions prepared from liver supernatant by ultrafiltration and alcohol precipitation also showed no specific effect on liver cells.

[Irradiation of solid Walker carcino-sarcomas after synchronisation with hydroxyurea (author's transl)].

Sprague-Dawley rats with solid Walker carcino-sarcomas were synchronized with hydroxyurea (HU; 6 x 50 mg and 1 x 300 mg HU/kg body weight) and then irradiated at different time points (60Co). The synchronized tumors showed a significant delay of growth when irradiation was applied in the late G1 phase, at the transition G1/S and in the early S phase. The remaining phases of the cell cycle, especially the S phase showed the same sensitivity as the non-synchronized controls.

[Studies in vivo and in vitro on the influence of 5-fluorouracil and n'-(2'-furanidyl)-5-fluorouracil on the walker carcinosarcoma 256 in the rat (author's transl)].

We compare the effects of 5-fluorouracil and N'-(2'-furanidyl)-5-fluorouracil (Ftorafur) in vivo (tumor size) and in vitro ([6-3H]-deoxyuridine incorporation) on solid Walker carcinosarcoma of the rat. 5-Fluorouracil and Ftorafur have a dose-dependent effect on tumor size and on [6-3H]-deoxyuridine incorporation in vitro. The in vivo effects on tumor size are similar when the dose of Ftorafur calculated by its molecular weight is about 3 times higher than that of 5-fluorouracil.