Nonprotein sulfhydryls as possible components of the protective effect of rosaprostol on the rat gastric mucosa

Experiments were designed to examine the possibility that nonprotein sulfhydryl groups of the gastric mucosa could participate in the protection of rat gastric mucosa by rosaprostol (the Na salt of 9-hydroxy-8,12 trans-19,20-bis-nor-prostanoic acid). Gastric mucosal lesions and the content of nonprotein sulfhydryls were evaluated after orally administered absolute ethanol. Pretreatment with rosaprostol by gavage prevented gastric lesions and reduced or prevented the decrease of mucosal nonprotein thiols. N-ethylmaleimide, a sulfhydryl blocker, worsened the ethanol-induced gastric lesions and lowered further the non protein thiols. Both variables were improved by the PG analogue and by PGE₂. These results suggest a possible role of endogenous nonprotein sulfhydryl groups in the gastric protective effect of rosaprostol.     

Organic Codes: A Unifying Concept for Life

Although the knowledge about biological systems has advanced exponentially in recent decades, it is surprising to realize that the very definition of Life keeps presenting theoretical challenges. Even if several lines of reasoning seek to identify the essence of life phenomenon, most of these thoughts contain fundamental problem in their basic conceptual structure. Most concepts fail to identify either necessary or sufficient features to define life. Here, we analyzed the main conceptual frameworks regarding theoretical aspects that have been supporting the most accepted concepts of life, such as (i) the physical, (ii) the cellular and (iii) the molecular approaches. Based on an ontological analysis, we propose that Life should not be positioned under the ontological category of Matter. Yet, life should be better understood under the top-level ontology of “Process”. Exercising an epistemological approach, we propose that the essential characteristic that pervades each and every living being is the presence of organic codes. Therefore, we explore theories in biosemiotics and code biology in order to propose a clear concept of life as a macrocode composed by multiple inter-related coding layers. This way, as life is a sort of metaphysical process of encoding, the living beings became the molecular materialization of that process. From the proposed concept, we show that the evolutionary process is a fundamental characteristic for life’s maintenance but it is not necessary to define life, as many organisms are clearly alive but they do not participate in the evolutionary process (such as infertile hybrids). The current proposition opens a fertile field of debate in astrobiology, epistemology, biosemiotics, code biology and robotics.

     

Effect of the three-dimensional organization of liver cells on the biogenesis of the γ-glutamyltransferase fraction pattern

Context Four gamma-glutamyltransferase (GGT) fractions with different molecular weights (big-, medium-, small- and free-GGT) are detectable in human plasma. Objective Verify if liver cells can release all four GGT fractions and if the spatial cell organization influences their release. Methods Hepatoma (HepG2) and melanoma (Me665/2/60) cells were cultured as monolayers or spheroids. GGT released in culture media was analysed by gel-filtration chromatography. Results HepG2 and Me665/2/60 monolayers released the b-GGT fraction, while significative levels of s-GGT and f-GGT were detectable only in media of HepG2-spheroids. Bile acids alone or in combination with papain promoted the conversion of b-GGT in s-GGT or f-GGT, respectively. Conclusions GGT is usually released as b-GGT, while s-GGT and f-GGT are likely to be produced in the liver extracellular environment by the combined action of bile acids and proteases.     

Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy

Brillouin spectroscopy is an emerging technique in the biomedical field. It probes the mechanical properties of a sample through the interaction of visible light with thermally induced acoustic waves or phonons propagating at a speed of a few km/sec. Information on the elasticity and structure of the material is obtained in a nondestructive contactless manner, hence opening the way to in vivo applications and potential diagnosis of pathology. This work describes the application of Brillouin spectroscopy to the study of biomechanics in elastin and trypsin-digested type I collagen fibers of the extracellular matrix. Fibrous proteins of the extracellular matrix are the building blocks of biological tissues and investigating their mechanical and physical behavior is key to establishing structure-function relationships in normal tissues and the changes which occur in disease. The procedures of sample preparation followed by measurement of Brillouin spectra using a reflective substrate are presented together with details of the optical system and methods of spectral data analysis.     

Three anthrones from Rubus ulmifolius

From the aerial parts of Rubus ulmifolius Schott three new anthrones, rubanthrone A, B and C, have been isolated. Their structures were established by spectral procedures including 1D and 2D NMR techniques and chemical derivatization. Rubanthrone A showed antimicrobial activity against Staphylococcus aureus at 4.5 mg/ml.     

The crisis of the thesis of climatic pessimism: malaria and the climatic question

The publication of Boudin's Traité de Geographie et de Statistique médicale (1857) and the creation in 1908 of the Institut de Pathologie Exotique by Laveran, correspond to two entirely different manners of considering tropical diseases and adaptability (or acclimatation) to the Tropics, directly associated with the idea of capability or incapability of Europeans to resist tropical diseases. We analyse the way perspectives have changed with respect to the influence that climate, particularly tropical, exert on the body of individuals and on populations used to live under temperate climatic conditions. The manner the concepts of medical geography, climatic pessimism and individual acclimatation get articulated with the discovery of tropical diseases, their aetiological agents and their localisation, particularly malaria, can only be understood by also analysing how the problems generated by the diversity of races and migration phenomena have been envisaged.     

Nonprotein sulfhydryls as possible components of the protective effect of rosaprostol on the rat gastric mucosa

Experiments were designed to examine the possibility that nonprotein sulfhydryl groups of the gastric mucosa could participate in the protection of rat gastric mucosa by rosaprostol (the Na salt of 9-hydroxy-8,12 trans-19,20-bis-nor-prostanoic acid). Gastric mucosal lesions and the content of nonprotein sulfhydryls were evaluated after orally administered absolute ethanol. Pretreatment with rosaprostol by gavage prevented gastric lesions and reduced or prevented the decrease of mucosal nonprotein thiols. N-ethylmaleimide, a sulfhydryl blocker, worsened the ethanol-induced gastric lesions and lowered further the non protein thiols. Both variables were improved by the PG analogue and by PGE2. These results suggest a possible role of endogenous nonprotein sulfhydryl groups in the gastric protective effect of rosaprostol.     

Immobilized methyltrioxo rhenium (MTO)/H2O2 systems for the oxidation of lignin and lignin model compounds

A convenient and efficient application of heterogeneous methylrhenium trioxide (MTO) systems for the selective oxidation of lignin model compounds and lignins is reported. Environmental friendly and low-cost H2O2 was used as the oxygen atom donor. Overall, the data presented and discussed in this paper point toward the conclusion that the immobilized heterogeneous catalytic systems based on H2O2/and MTO catalysts are able to extensively oxidize both phenolic and non-phenolic, monomeric, and dimeric, lignin model compounds. Condensed diphenylmethane models were found also extensively oxidized. Technical lignins, such as hydrolytic sugar cane lignin (SCL) and red spruce kraft lignin (RSL), displayed oxidative activity with immobilized MTO catalytic systems. After oxidation, these lignins displayed the formation of more soluble lignin fragments with a high degree of degradation as indicated by the lower contents of aliphatic and condensed OH groups, and the higher amounts of carboxylic acid moieties. Our data indicate that immobilized MTO catalytic systems are significant potential candidates for the development of alternative totally chlorine-free delignification processes and environmental sustainable lignin selective modification reactions.