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Biomedical subjects

J C Escudero

Publications and source records attributed to J C Escudero.

11 recordsLinked to original sources
PubMed2001

Identification and effects of interaction phytotoxic compounds from exudate of Cistus ladanifer leaves.

Eleven allelochemicals (ferulic acid, cinnamic acid, 4-hydroxybenzoic acid, hydroxycinnamic acid, methyl propionate, oxalic acid, methylmalonic acid, p-anisic acid, butyric acid, 3-hydroxybutyric acid, and azulene) were identified in the exudate of Cistus ladanifer L. We studied the effect of each on germination, cotyledon emergence, root length, and cotyledon length of Rumex crispus. Three groups were distinguished with respect to phytotoxic activity: compounds with low activity (ferulic acid, 4-hydroxybenzoic acid, oxalic acid, methylmalonic acid, p-anisic acid, hydroxybutyric acid, and azulene), with intermediate activity (cinnamic acid and hydroxycinnamic acid), and with high activity (methyl propionate and butyric acid). The effect of the interaction of the compounds was studied. When acting conjointly, all combinations tested produced a more negative effect on both germination and seedling growth than when acting alone. The interaction affected cotyledon emergence and root length more negatively than germination and cotyledon length. When hydroxycinnamic acid and cinnamic acid were added to these mixtures there was an enhancement in the phytotoxic activity, accentuating the effect of the other allelochemicals.

3-Hydroxybutyric Acid↗
PubMed2001

Plant growth inhibiting flavonoids in exudate of Cistus ladanifer and in associated soils.

Of the aglycone flavonoids identified in the exudate of cistus ladanifer, two, the flavone apigenin-4'-(O)-methyl and the flavonol kaempferol-3,7-di(O)-methyl inhibit development of the seedlings of Rumex crispus at 0.5 and 1 mM. Additive effects were observed between the major flavonols of the exudate kaempferol-3-(O)-methyl and kaempferol-3,7-di-(O)-methyl in inhibiting the size of the cotyledons and delaying the germination and cotyledon emergence. The presence of apigenin-4'-(O)-methyl, kaempferol-3,7-di-(O)-methyl, and kaempferol-3-(O)-methyl was detected in the soils associated with C. ladanifer during the summer and autumn months. That these compounds are present in the soil and are not restricted to the leaves provides support for the hypothesis that C. ladanifer has allelopathic potential.

Biological Assay↗
PubMed1999

The Escherichia coli trmE (mnmE) gene, involved in tRNA modification, codes for an evolutionarily conserved GTPase with unusual biochemical properties.

The evolutionarily conserved 50K protein of Escherichia coli, encoded by o454, contains a consensus GTP-binding motif. Here we show that 50K is a GTPase that differs extensively from regulatory GTPases such as p21. Thus, 50K exhibits a very high intrinsic GTPase hydrolysis rate, rather low affinity for GTP, and extremely low affinity for GDP. Moreover, it can form self-assemblies. Strikingly, the 17 kDa GTPase domain of 50K conserves the guanine nucleotide-binding and GTPase activities of the intact 50K molecule. Therefore, the structural requirements for GTP binding and GTP hydrolysis by 50K are without precedent and justify a separate classification in the GTPase superfamily. Immunoelectron microscopy reveals that 50K is a cytoplasmic protein partially associated with the inner membrane. We prove that o454 is allelic with trmE, a gene involved in the biosynthesis of the hypermodified nucleoside 5-methylaminomethyl-2-thiouridine, which is found in the wobble position of some tRNAs. Our results demonstrate that 50K is essential for viability depending on the genetic background. We propose that combination of mutations affecting the decoding process, which separately do not reveal an obvious defect in growth, can give rise to lethal phenotypes, most likely due to synergism.

Base Sequence↗
PubMed1981

Democracy, authoritarianism, and health in Argentina.

The democracy-participation-better health versus authoritarianism-repression-worse health polarity is illustrated by the case of health policy in Argentina. At the turn of the century, Argentina's health levels were among the highest in the world. The subsequent deterioration can be correlated with disruptions of the country's democratic process. The participation of the military in Argentinian political life has produced a lowering of the standard of living of the majority of the population, with a consequent increase in mortality and morbidity, and the appearance of elitist, commodity-centered health policies. the anti-health policies of the military are contrasted with those pursued by democratically elected Argentinian governments, as well as the principles set forth in recent declarations of human rights.

Argentina↗
PubMed1980

On lies and health statistics: some Latin American examples.

New methods of demographic analysis are producing estimates of fertility and mortality which are sometimes at great variance with "official" figures generated by the statistics organizations of the different countries and which are reproduced in international reference books. This discrepancy is greatest with regard to infant mortality. Using Latin American examples, the magnitude of this discrepancy is explored, biases in estimating causes of mortality are identified, and a consideration is made of morbidity figures, which, as they are generated by health care systems with very low coverages of population, tend to seriously underrepresent the prevalent levels of disease. A structural interpretaton is made of the Latin American situation, linking this crisis of health statistics with a more general crisis of the "developmentist" model under which these systems flourished, and with an upsurge in political repression in the Continent which will tend in future to increase the inaccuracy of "official" health statistics data. Finally, alternative health statistics procedures are proposed.

Child, Preschool↗
PubMed1980

Starting from year one: the politics of health in Nicaragua.

The triumphant Sandinista revolution inherited a health situation characterized by high mortality, low life expectancy, widespread malnutrition, and a medical system limited in scope. The extent of these problems can only be estimated as a result of the somocista government's failure to develop an accurate system of vital statistics. While there are many options available for rapidly decreasing the high levels of mortality and morbidity in Nicaragua, the revolutionary government has chosen a strategy which fuses public health and politics. A health network based on popular participation and control is being formed which should not only decrease the high rates of malnutrition and infectious diseases in a cost-efficient manner, but should increase the strength of the revolution as well.

Community Health Services↗
PubMed1978

Health in Argentina under the Military Junta.

The socioeconomic policies of Argentina's Military Junta, in power since March 1976, have led to a sharp impoverishment of the vast majority of the population. In the health sector, facilities which previously were public are being transferred to the private sector, and public hospitals formerly providing free services to the population now charge patients for the care received. As a necessary counterpart to these unpopular measures, a regime of terror has been waged against members of the health team--both those politically active and those considered potentially subversive, particularly the psychiatrists and workers in community health. Differences between the Argentinian situation and previous European fascist patterns are noted, and the possibility of use of the "Argentinian model" in other capitalist countries in crisis is discussed.

Argentina↗
PubMed1978

The magnitude of malnutrition in Latin America.

Malnutrition, an illness which can easily be prevented and cured with existing resources and technology, is perhaps the most widespread disease in Latin America. However, it is unrecognized as such, and those population groups that suffer most from it are most prone to have their sufferings unrecorded. Two factors contribute to this: (a) the inaccuracy and incomplete coverage of vital statistics, as reflected by underregistration of deaths, insufficient medical certification of registered deaths, and biases both among certifying physicians and in the International Classification of Diseases; and (b) low population coverage by the health care systems and thus by the statistics which they generate. These factors are related to the ideological bias of those statistical systems and to the concepts of causality which they use. Through a review and analysis of "ad hoc" studies on the frequency of malnutrition in Latin America and its incidence in relation to morbidity and mortality, an estimation is made of malnutrition-caused deaths, which would amount to almost one-fifth of deaths from all causes. As overall availability of food in Latin America is adequate, it is held that this continent ultimately has the level of malnutrition that it wishes to have.

Child, Preschool↗
PubMed1976

[Not Available].

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Americas↗