Serotonin and its metabolites; their respective roles in the production of hypothermia in the mouse

Zusammenfassung In Mäuseversuchen wurde gezeigt, dass nicht Serotonin, sondern zwei seiner Metaboliten (5-Hydroxytryptophol oder dessen Ausgangsstoff 5-Hydroxyindolacetaldehyd) die Hypothermie erzeugen.     

Genera and species vs. laws of nature two epistemic frameworks and their respective ideal worlds

This paper seeks to exhibit and explain, by way of comparison, two ideal kinds of knowledge: knowledge based on classifications according to genera and species, as in Aristotelianism and common sense, and scientific knowledge based on the application of laws of nature. I will proceed by attempting (1) to determine the role that presuppositions play in knowledge in general by means of the distinction between content and form; (2) to describe and explain the main features of both ideal forms of knowledge; and, finally, (3) to analyze the relation between these two forms of knowledge as it is presented in Eddington's celebrated discussion of the “two tables”. I will be critical of the widespread view that modern science is the correct form of knowledge, and that common sense is merely an illusion.     

Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions

Summary A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.This investigation was supported by grant CA-18628, awarded by the National Cancer Institute, Department of Health and Human Services.     

On the distribution in brain of monoamines and of enzymes responsible for their formation

Zusammenfassung Im menschlichen Gehirn kommen grosse Mengen von 3-Hydroxytyramin im Nucleus Caudatus und dem Putamen vor.Injektion von 3,4-Dihydroxyphenylalanin in Kaninchen bringt eine schnelle Akkumulation von 3-Hydroxytyramin in den Gehirnteilen, die reich an Katecholaminen sind, zustande. Die Fähigkeit das akkumulierte 3-Hydroxytyramin abzubauen scheint im ganzen Gehirn dieselbe zu sein.Hemmungsversuche und Aktivitätsuntersuchungen der Fermente in verschiedenen Gehirnteilenin vitro sprechen dafür, dass 5-Hydroxytryptophan und 3,4-Dihydroxyphenylalanin von einem und demselben Ferment decarboxyliert werden.     

Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions

A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.     

Electrophoretic variation in esterases in 3 wild-type and respective mutant strains ofAspergillus flavus

Summary Wild-type strains and auxotrophic mutants ofAspergillus flavus, differing regarding aflatoxin production, were tested for esterases isozymes. Esterases variation was found in all strains used, and a possible correlation between the pattern of esterase bands and aflatoxin production is suggested.Acknowledgment. The authors are thankful to the National Council for the development of Science and Technology (CNPq) and Assistance to Research for São Paulo State (FAPESP) for financial assistance.     

Electrophoretic variation in esterases in 3 wild-type and respective mutant strains of Aspergillus flavus.

Wild-type strains and auxotrophic mutants of Aspergillus flavus, differing regarding aflatoxin production, were tested for esterases isozymes. Esterases variation was found in all strains used, and a possible correlation between the pattern of esterase bands and aflatoxin production is suggested.     

Structure, mechanism and catalytic duality of thiamine-dependent enzymes

Thiamine is an essential cofactor that is required for processes of general metabolism amongst all organisms, and it is likely to have played a role in the earliest stages of the evolution of life. Here, we review from a structural perspective the enzymatic mechanisms that involve this cofactor. We explore asymmetry within homodimeric thiamine diphosphate (ThDP)-dependent enzyme structures and discuss how this may be correlated with the kinetic properties of half-of-the-sites reactivity, and negative cooperativity. It is likely these structural and kinetic hallmarks may arise through reciprocal coupling of active sites. This mode of communication between distant active sites is not unique to ThDP-dependent enzymes, but is widespread in other classes of oligomeric enzyme. Thus, it appears likely to be a general phenomenon reflecting a powerful mechanism of accelerating the rate of a chemical pathway. Finally, we speculate on the early evolutionary history of the cofactor and its ancient association with protein and RNA.     

Blastomitogenic agents in leguminosae and other families

Résumé Des agents blastomitogéniques furent décelés non seulement dans les extraits de 4 genres propres à la famille des Légumineuses, mais aussi dans les graines d'espèces déterminées appartenant aux familles des Solanacées, Composées, Ephédracées et Clusiacées. Ces 4 dernières sources, non mentionnées au préalable, témoignent de la répartition variée de ces agents dans la nature et donnent lieu à des conjectures aux points de vue de leur affinité chimique, du mécanisme de leur action blastomitogénique, de leur rôle dans la physiologie végétale et de leur importance dans l'évolution.     

Bradykinin,kallidin, and their synthetic analogues

Zusammenfassung Biochemie und Pharmakologie der drei natürlich vorkommenden und in der Struktur bekannten Kinine — Bradykinin, Kallidin und Methionyl-Lysyl-Bradykinin — sowie deren Synthesen werden besprochen. Für die bisher bekannten 70 Analoga des Bradykinins und Kallidins wurden die biologischen Eigenschaften (Rattenuterus, Meerschweinchenileum, Kaninchenblutdruck, Meerschweinchenblutdruck, Rattenblutdruck, Bronchokonstriktoraktivität) tabellarisch zusammengestellt. Die einzelnen Analoga werden untereinander verglichen und Beziehungen zwischen Struktur und Wirksamkeit diskutiert.     

Persistent and atypical lobules in the human breast may be precancerous

Summary Persistent human mammary lobules (PL) remaining after the menopause, and certain atypical lobules (ALA) are morphologically similar to the common preneoplastic hyperplastic alveolar nodule (HAN) of mice of strains having a high incidence of mammary carcinoma. This and other evidence suggest that like the HAN of mice human PL and ALA are precancerous.This work was supported by a contract from the National Institutes of Health. PHS NOI-CB-43908, and funds from the Cancer Research Coordinating Committee, University of California.     

Revisiting the enzymes stored in the laticifers of Carica papaya in the context of their possible participation in the plant defence mechanism

In the tropical species Carica papaya, the articulated and anastomosing laticifers form a dense network of vessels displayed in all aerial parts of the plant. Damaging the papaya tree inevitably severs its laticifers, eliciting an abrupt release of latex. Besides the well-known cysteine proteinases, papain, chymopapain, caricain and glycyl endopeptidase, papaya latex is also a rich source of other enzymes. Together, these enzymes could provide an important contribution to plant defence mechanisms by sanitising and sealing the wounded areas on the tree.