Carcinogen-Induced Tumors of the Thymus. III. Restoration of Neonatally Thymectomized Mice With Thymomas in Cell-Impermeable Chambers2

1969 ◽  
Vol 130 (4) ◽  
pp. 809-819 ◽  
Author(s):  
Osias Stutman ◽  
Edmond J. Yunis ◽  
Robert A. Good

A progressive decrease of the restoring effectivity of syngeneic or allogeneic thymus and functional thymoma grafts was observed when the treatment of neonatally thymectomized mice was delayed. Early treatment (5–20 days postthymectomy) was effective, while the number of restored animals was markedly decreased after late treatment (30–50 days postthymectomy). Similar results were obtained with subcutaneous or intraperitoneal thymus grafts and with thymus grafts within cell-impenetrable diffusion chambers. After the onset of the postthymectomy-wasting syndrome the only successful treatment was the implantation of multiple thymus grafts. On the other hand, single thymus grafts, thymoma grafts, or thymus or thymoma within diffusion chambers were ineffective. When spleen cells from 5-day old or 45-day old neonatally thymectomized animals were given in association with thymoma grafts, only the cells derived from the 5-day old thymectomized mice proved effective in restoring wasted thymectomized hosts. These results suggest that a population of cells sensitive to the action of the thymus decreases progressively with time in the absence of thymic function.


1985 ◽  
Vol 5 (6) ◽  
pp. 925-935 ◽  
Author(s):  
W. Lijinsky ◽  
R. M. Kovatch

To relate the tumorigenic effects of directly acting alkylating nitrosoalkylureas to their chemical structure, a series of these compounds was given to F344 rats by gavage at approximately equimolar doses. In some cases, more than one dose rate was used. Potency, as measured by time to death with tumors, was similar for nitrosomethylurea and nitrosoethylurea, although the tumor pattern was different between the two. Nitrosoallylurea was of similar potency, and induced a spectrum of tumors similar to nitrosoethylurea. Nitroso-n-butyl-, n-amyl- and n-hexyl-ureas were less potent than nitrosoethylurea, but induced a similar pattern of tumors. All of the nitrosoureas induced tumors of the forestomach, usually in high incidence, except nitroso-2-hydroxypropylurea, which caused death of the rats with thymic lymphoma within 6 months. Nitroso-3-hydroxypropylurea was much less potent than its 2-isomer, but induced no tumors of the thymus and was the only one of this group to induce tumors of the glandular stomach. Only nitrosomethylurea induced a high incidence of tumors of the nervous system, but no mammary carcinomas, which most of the other nitrosoureas induced in high incidence in females. Tumors of the lung, duodenum, colon and intestines were induced by several of the compounds, more commonly in males than in females, but a high incidence of liver tumors was found only in rats of both sexes given nitroso-2-phenylethylurea.


Author(s):  
A. E. Vatter ◽  
J. Zambernard

Oncogenic viruses, like viruses in general, can be divided into two classes, those that contain deoxyribonucleic acid (DNA) and those that contain ribonucleic acid (RNA). The RNA viruses have been recovered readily from the tumors which they cause whereas, the DNA-virus induced tumors have not yielded the virus. Since DNA viruses cannot be recovered, the bulk of present day investigations have been concerned with RNA viruses.The Lucké renal adenocarcinoma is a spontaneous tumor which occurs in northern leopard frogs (Rana pipiens) and has received increased attention in recent years because of its probable viral etiology. This hypothesis was first advanced by Lucké after he observed intranuclear inclusions in some of the tumor cells. Tumors with inclusions were examined at the fine structural level by Fawcett who showed that they contained immature and mature virus˗like particles.The use of this system in the study of oncogenic tumors offers several unique features, the virus has been shown to contain DNA and it can be recovered from the tumor, also, it is temperature sensitive. This latter feature is of importance because the virus can be transformed from a latent to a vegetative state by lowering or elevating the environmental temperature.


2020 ◽  
Author(s):  
Lungwani Muungo

Tumor hypoxia and hypoxia-inducible factor 1 (HIF-1) activationare associated with cancer progression. Here, we demonstrate thatthe transcription factor TAp73 opposes HIF-1 activity through anontranscriptional mechanism, thus affecting tumor angiogenesis.TAp73-deficient mice have an increased incidence of spontaneousand chemically induced tumors that also display enhanced vascularization.Mechanistically, TAp73 interacts with the regulatory subunit(α) of HIF-1 and recruits mouse double minute 2 homolog intothe protein complex, thus promoting HIF-1α polyubiquitination andconsequent proteasomal degradation in an oxygen-independentmanner. In human lung cancer datasets, TAp73 strongly predictsgood patient prognosis, and its expression is associated with lowHIF-1 activation and angiogenesis. Our findings, supported by invivo and clinical evidence, demonstrate a mechanism for oxygenindependentHIF-1 regulation, which has important implicationsfor individualizing therapies in patients with cancer.


2015 ◽  
Vol 22 (8) ◽  
pp. 958-974 ◽  
Author(s):  
Maria Chiantore ◽  
Giorgio Mangino ◽  
Maria Zangrillo ◽  
Marco Iuliano ◽  
Elisabetta Affabris ◽  
...  
Keyword(s):  

1964 ◽  
Vol 40 (6) ◽  
pp. 445-447 ◽  
Author(s):  
Ryoichi MORI ◽  
Kikuo NOMOTO ◽  
Kenji TAKEYA

1976 ◽  
Vol 17 (3) ◽  
pp. 824-831 ◽  
Author(s):  
W D Lancaster ◽  
C Olson ◽  
W Meinke
Keyword(s):  

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3260
Author(s):  
Yu-Hsiang Lin ◽  
Chi-Chung Wang ◽  
Ying-Hung Lin ◽  
Bing-Huei Chen

Anti-cancer activity of catechin nanoemulsions prepared from Oolong tea leaf waste was studied on prostate cancer cells DU-145 and DU-145-induced tumors in mice. Catechin nanoemulsions composed of lecithin, Tween-80 and water in an appropriate proportion was prepared with high stability, particle size of 11.3 nm, zeta potential of −67.2 mV and encapsulation efficiency of 83.4%. Catechin nanoemulsions were more effective than extracts in inhibiting DU-145 cell growth, with the IC50 being 13.52 and 214.6 μg/mL, respectively, after 48 h incubation. Furthermore, both catechin nanoemulsions and extracts could raise caspase-8, caspase-9 and caspase-3 activities for DU-145 cell apoptosis, arresting the cell cycle at S and G2/M phases. Compared to control, catechin nanoemulsion at 20 μg/mL and paclitaxel at 10 μg/mL were the most effective in reducing tumor volume by 41.3% and 52.5% and tumor weight by 77.5% and 90.6% in mice, respectively, through a decrease in EGF and VEGF levels in serum.


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