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S Pavel

Publications and source records attributed to S Pavel.

At least 109 records · Page 6Linked to original sources
PubMed1979

Comparison of the excretion of different types of melanogens in the melanoma patients.

Urinary melanogens are indolic and phenolic compounds which are excreted in an elevated amount in the urine of melanoma patients. Urinary melanogens can be divided into two principal groups according to their behavior during Thormählen test--Thormählen positive melanogens (TPM) and Thormählen negative melanogens (TNM). When comparing TPM and TNM (represented by homovanillic and vanillactic acids) urinary excretion in stage III of melanoma patients we have found two significantly different relations for melanogens excretion, i. e. predominating TPM urinary excretion in melanotic forms of melanomas and predominating homovanillic acid and vanillactic acid urinary excretion in amelanotic forms of melanomas. We assumed that it could be an indirect evidence of the different catalytic activity of either cresolase or catecholase activities of tyrosinase.

Eye Neoplasms↗
PubMed1979

Excretion of melanogens and zinc during the growth of melanoma in hamsters.

Melanogens which are considered as probable precursors or their metabolites in the metabolic pathway toward melanin are excreted in an increasing amount during the melanotic melanoma growth in hamsters. Moreover, an increased excretion of zinc was observed. The evaluation of dependence between zinc and Thormählen positive melanogens excretions during the melanoma growth suggests an exponential type of dependence. Likewise as in the case of human melanoma the hyperzincuria proved to be a laboratory sign of tumor disease progression in Syrian hamsters as well. The cause of an increased zinc excretion during the melanoma growth seems to consist in an increased lysis of pigment cells. The presumed destruction of tumor cells was not accompanied by a higher excretion of magnesium, though. Concentration of creatinine proved to be a useful mean for expressing of standard excretion of various substances also in hamsters.

Animals↗
PubMed1978

Simple screening test for estimation of some phenolic and indolic compounds in urine application to melanoma.

A simple screening test for estimation of some phenolic and indolic compounds in urine is described. The method is rapid, simple and able to detect all the indolic and phenolic compounds observed, including o-dihydroxy compounds. The method is based on the color reaction with reagent solution composed of sodium tungstate, trichloroacetic acid, hydrochloric acid and sodium nitrite. After alkalinization by sodium hydroxide the optical density is measured at 405 and 490 nm. The latter is specific for o-dihydroxy compounds. This test seems to be useful for estimation of phenolic and indolic compounds in urine of patients with increased production of compounds of this nature, particularly in some tumors.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Arginine vasotocin as a pineal hormone.

The pineal nonapeptide hormone arginine vasotocin (AVT) is synthesized by the ependymal cells of the pineal recess and subcommissural organ and stored in so far undefined cells of the pineal gland proper. AVT is first released into the cerebrospinal fluid (CSF) and reaches the blood only secondarily after its absorption from CSF. It displays a diurnal rhythm in the pineal and CSF, suggesting its release into the CSF during the night in the dark. Melatonin represents its releasing hormone. AVT exerts both its endocrine and non-endocrine effects by a unique mechanism involving the activation of serotonin neurotransmission in the brain with resultant inhibition of release of hypothalamic releasing and inhibiting hormones and induction of sleep. It produces both its endocrine effects and sleep at concentrations equivalent to only several hundreds of molecules, being thus by far the most active hormone so far known. Midbrain raphe nuclei or some structures intimately correlated with these cell bodies, most contain the extremely sensitive and specific AVT receptors in the mammalian brain. In contrast with its natural analogues arginine vasopressin and oxytocin which are mainly blood hormones, AVT is a CSF hormone whose major if not the sole site of action is the brain itself.

Adrenocorticotropic Hormone↗
PubMed1978

[Pheomelanins].

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Animals↗