Biomedical subjects

Francisco Arvelo

Publications and source records attributed to Francisco Arvelo.

7 recordsLinked to original sources

PubMed2006

[Metalloproteinases in tumor progression. Review].

The two biological characteristics that determine the malignancy of cancer are infiltration and metastasis. The study of these mechanisms is related to the invasion of tumoral cells and the relationship of these cells with their stroma, which interact producing the movement and accumulation of inflammatory cells, the formation of new blood vessels, multiplication of fibroblasts and the synthesis of the components of the extra cellular matrix production. Tumoral invasion is conditioned through various enzyme activities, in particular proteases which degrade the matrix, thus facilitating the progression of the tumor. The metalloproteinases (MMP) are a family of proteinases that play an important role in cancer as well as in numerous other diseases. MMP are, therefore, a potential factor in cancer therapy. Several synthetic MMP inhibitors have been developed and have shown successful anti-tumor activity in a variety of animal species, but in clinical studies of patients with advanced forms of cancer, this therapeutic strategy has not resulted as effective. In this article, due to the biological and clinical importance of this therapy, we summarize the current views on the role of metalloproteinases (MMP) in tumor promotion, proliferation, invasion, metastasis and angiogenesis.

Animals↗

PubMed2005

Cytotoxic and proapoptotic activity of ent-16beta-17alpha-dihydroxykaurane on human mammary carcinoma cell line MCF-7.

Here we describe the cytotoxic and proapoptotic effect of an ent-kaurane (ent-16beta-17alpha-dihydroxykaurane), compound isolated from Croton malambo barks, on malignant cell growth. When MCF-7 mammary carcinoma cells were treated with increasing concentrations of the ent-kauranoid, its cytotoxic activity showed an IC50 of 12.5microg/ml, dose that is 2.66-fold lower than the corresponding value for non-malignant cells. At this growth inhibitory dose, both mRNA and protein levels for Bcl-2 as well as mRNA for hTERT were significantly reduced. The observed preapoptotic activity seemed to be triggered by a mechanism that is not directly affecting NF-(kappa)B binding ability. The potential use of this plant-derived compound as a cancer chemotherapy agent is discussed.

Apoptosis↗

PubMed2005

New cytotoxic isoflavone from the root bark of Brosimum utile.

A new isoflavone 5,7,4'-trihydroxy-3'-(3-hydroxy-3-methylbutyl)isoflavone (isowigtheone hydrate) (1), together with six known isoflavones 2-7 and (-)epicatechin, were isolated from the root barks of Brosimum utile. Their structures were established on the basis of spectroscopic evidence. The in vitro cytotoxic activity of the new compound 1 was evaluated against cell lines MCF7 (human breast carcinoma), PC3 (human prostate carcinoma), HT29 (human colon cancer) and human dermis fibroblasts.

Antineoplastic Agents, Phytogenic↗

PubMed2004

Three new glutarimide alkaloids from Croton cuneatus.

Analysis of the dichloromethane extract of the aerial parts of Croton cuneatus led to the isolation of the new glutarimide alkaloids: julocrotol (1), isojulocrotol (2), and julocrotone (3) along with the known compounds julocrotonine (4), lichexanthone (5) and selin-11-en-4alpha-ol (6). The structures of the new compounds were established by spectral methods. The in vitro cytotoxic activity of Compounds 1-6 was evaluated against six human tumor cells lines.

Alkaloids↗

PubMed2004

[Obtention of human skin sheets by means of tissue engineering].

The aim of this "in vitro" study was to develop a new system for keratinocyte culture on a dermal equivalent that enables treatment of different skin injuries. The keratinocyte where obtained from primary cell cultures derived from skin biopsies, seeded over a fibrin matrix enhanced with live human fibroblast. Cells growing over the dermal equivalent, rapidly confluences and a stratified epithelium was obtained within 20-25 days culture. Detachment of composite culture from flask is a simple and quick procedure with no need for chemical or enzyme treatments. The method described provides a number of advantages which include the large expansion of keratinocyte from the primary cell cultures without the need of a feeder layer, the availability of plasma from blood banks, and the versatile and safe manipulation of composite obtained "in vitro". All these facts allow to assure that this system could result very efficient for the treatment of all type of skin injuries.

Cell Culture Techniques↗

PubMed2002

[Participation of dexamethasone and E and C vitamins in the modulation of the hepatotoxic effect induced by fomesafen and 2,4-D amino herbicides, in rats ].

The fomesafen and 2,4-D amine herbicide induce cytotoxic effects at hepatic level in rats, such as: hepatomegaly, hyperplasia and increase in the enzymes activity which participate in the processes of peroxisomal beta-oxidation of fatty acids. In this work, the effect of vitamin E and C was evaluated, as well as, the dexamethasone in the modulation of these hepatotoxic effects. Sprague-Dawley rats were treated with the herbicides and with the agents to be evaluated. The different treatments were given during 15 days orally route. The herbicides combined with the dexamethasone and antioxidant agents were administrated only and simultaneously with the herbicides. Once concluded the different treatment, the rats were weighed and sacrificed. It was evaluated the liver size and liver fragments were obtained to determine the enzymatic activity of Fatty Acyl CoA-oxidase (FACO) and cellular number. The results showed that the hepatomegaly induced by fomesafen was inhibited by the vitamins and by the dexamethasone, while any effect was not observed in the group of rats treated with 2,4-D amine. None of the agents modulated the FACO activity induced by herbicides in treated rats. However, the dexamethasone showed a protective effect in the hyperplasia induced by two herbicides. The hepatotoxic effects induced by the herbicides responded to a different mechanism due to the differences of the effects observed at the antioxidant agents. On the other hand, the inhibition of the cellular proliferation by the dexamethasone does not keep relation with the responsible mechanisms of inducing the oxidant stress into FACO activity. Under experimental conditions of this study, the use of these agents does not guarantee protection against the hepatotoxic effects induced by the herbicides.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2002

[Mitochondria and apoptosis].

It is now accepted that mitochondria are endosymbionts, originated in aerobic bacteria which were integrated by the ancestor of eukaryotic cells. A part of the apoptotic machinery could exist in unicellular eukaryotic and some controlling apoptosis components might be present in prokaryotes. It is therefore possible that the mechanism originally involved in the maintenance of the symbiosis between the bacterial ancestor of the mitochondria and the host cell precursor of eukaryotes, provided the basis for the actual mechanism controlling cell survival. Metazoans would have improved this possibility by connecting to the mitochondria as principal effector of cellular death to the pathways of signal transduction. A variety of events appoint to the mitochondria as principal effector of the apoptosis. This including the release caspase activators (cytochrome c), changes in electron transport, loss of mitochondrial transmembrane potential, altered cellular oxidation-reduction, and participation of pro and antiapoptotic Bcl-2 proteins. The different signals that converge on mitochondria for activation or inhibition of these events, delineate several pathways in the physiology of the cellular death.

Apoptosis↗