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V Lapin

Publications and source records attributed to V Lapin.

17 recordsLinked to original sources
PubMed1981

The role of the pineal gland in neuroendocrine control mechanisms of neoplastic growth.

A survey of papers read during a workshop held in Vienna, 1977, is given showing that the pineal gland can be considered a model for research on neuroendocrine control mechanisms in neoplastic growth. From data obtained by different authors it can be concluded that the role of the pineal indole melatonin is very important in regard of the incidence and the development of tumours. On the basis of all the facts mentioned in this paper it is obvious that pineal gland activity should be included into the neuroendocrine factors studied in relation with oncogenic processes. For future research a number of experimental approaches, which need special emphasis, are recommended.

Animals↗
PubMed1981

Effects of growing tumours on pineal melatonin levels in male rats.

The effect of transplantable tumours (Yoshida Sarcoma) on pineal melatonin content was studied in Wistar rats. A negative correlation between pineal melatonin content and size of growing tumours was observed. Effects of chronic treatment with drugs interfering with n=melatonin or serotonin biosynthesis on tumour growth as well as the influence of tumour growth on pineal melatonin content were investigated. Tumour growth enhancement observed after administration of some substances producing a decrease of pineal melatonin is discussed. Pinealectomy stimulates malignant growth. This may be caused by lack of endogenous melatonin.

5-Hydroxytryptophan↗
PubMed1979

Effects of sham-pinealectomy, performed under white and red light, on the melatonin content of rat pineal glands.

Sham-pinealectomy, performed under different light conditons in newborn and adult rats, is followed by changes of pineal activity resulting in variations of melatonin content. The pineal glands of rats sham-operated under white light produce significantly less melatonin. In contrast, glands of rats operated on under red light show a melatonin content corresponding to that of intact rats. This result implies that normal white light causes a disturbance in melatonin production by a non-retinal pathway.

Aging↗
PubMed1978

[Effect of reserpine on the formation of 9,10-dimethyl-1,2-benzanthracene induced tumors in pinealectomized and thymectomized rats].

After reserpine treatment the incidence of dimethylbenzanthracene-induced tumors was found to be significantly higher in pinealectomized rats than in intact or thymectomized ones. A very high rate of DMBA-leukemia was observed in immune-deficient pinealectomized rats after reserpine administration. It is therefore suggested that the neuroendocrine disturbances due to removal of the pineal gland in the newborn animals, are latent and become evident after reserpine administration as reflected in an increased tumor incidence.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

[Phylogenetic aspects of acquired immunity].

A review of literature on phylogenesis of acquired immunity shows an increasing activity and potential of this complex apparatus. This system is responsible for the immunosurveillance, i.e. the control and recognition of transformed cells. Obviously the functions and morphology of the immune competent apparatus become more active and specific with growing complexity of living conditions. Since organisms become the more vulnerable the higher stages of development are reached, the sense of this evolution lies in protecting these organisms against environmental influences and in allowing survival. Recognition and elimination of malignant cells is part of this capacity acquired by evolution.

Animals↗
PubMed1978

Effects of reserpine on the incidence of 9,10-dimethyl-1,2-benzanthracene-induced tumors in pinealectomised and thymectomised rats.

After reserpine treatment the incidence of dimethyl-benzathrance-induced tumors was found to be significantly higher in pinealectomised rats than in intact or thymectomised ones. A very high rate of DMBA-leukemia was observed in immune deficient pinealectomised rats after reserpine administration. It is therefore suggested that the neuro-endocrine disturbances, due to removal of the pineal gland in the new-born animals, are latent and become evident after reserpine administration, as reflected in an increased tumor incidence.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1976

Immunocompetence of pinealectomized and simultaneously pinealectomized and thymectomized rats.

The cellular and antibody-mediated immune responsiveness was studied in adult rats which had the pineal and/or the thymus gland removed within 36 hours after birth. The immunolgical parameters measured were: Skin graft rejection, haemolytic plaque formation, and haemagglutinating antibody formation in response to sheep red blood cells and the stimulation of lymphoid cells from the spleen by phytohaemagglutinin in lipopolysaccharide. The removal of the pineal gland had little effect on the degree of immunocompetence in normal or immunosuppressed animals. In some of the immunological tests an accelerated response was observed, which suggests that lymphoid cells from pinealectomized or pinealectomized-thymectomized animals proliferate more rapidly upon contact with antigen or mitogen. This accelerated cell proliferation, unlike the immunodepression of the host, could explain the enhanced growth of transplantable tumors observed in pinealectomized animals.

Animals↗
PubMed1976

Effects of some low molecular weight sheep pineal fractions and melatonin on different tumors in rats and mice.

With these preliminary experiments attention is drawn to a possible relation between tumor development and the pineal. The influence of melatonin and some low molecular weight pineal fractions on the growth and incidence of different experimental tumors was compared. Some pineal fractions which have an effect on the activity of hypothalamus on anterior hypophyses of male rats and mice in vitro may be active in some of these tumor models.

Animals↗
PubMed1975

The influence of pinealectomy and of pinealectomy combined with thymectomy oncogenesis caused by polyoma virus in rats.

The inoculation of Polyoma virus suspension to neonatal pinealectomized rats did not provoke a growth of neoplasia. However, if the pinealectomy was combined with neonatal thymectomy, renal tumors occured in a rate of 50 of animals. An incidence of renal tumors was observed also in 57.6% of thymectomized rats, but not in non operated control group. The stimulating effect of pinealectomy on the growth of transplantable tumors has already been described several times (2, 3, 6, 8). The question of a possible change in the viral oncogenesis after pinealectomy was raised. For this reason Polyoma virus was used and its oncogenic effect was studied on the neonatally pinealectomized rats, on rats neonatally thymectomized and on neonatally pinealectomized rats which were simultaneously thymectomized.

Animals↗