Interaction between areas of the central nervous system in the control of water intake and arterial pressure in rats

1. Water intake induced by injection of 0.2 M-NaCl into the lateral preoptic area was increased by the injection of angiotensin II into the subfornical organ of rats. The injection of hypertonic saline solution into the subfornical organ increased water intake. However, the increase was lower than when the solution was injected into the lateral preoptic area. The injection of 4 μg angiotensin II into the lateral preoptic area further augmented this effect. 2. Injection of angiotensin II into the subfornical organ caused a rise in blood pressure which preceded the thirst-inducing effect. The injection of 0.2 M NaCl into the subfornical organ caused no changes in blood pressure, whereas the injection of angiotensin II into the lateral preoptic area caused some increase. 3. Dehydration of the lateral preoptic area by means of 0.2 M NaCl in combination with intravenous infusion of angiotensin II caused a summation of effects in terms of the water intake, without changing cardiovascular alterations induced by the infusion of angiotensin II. A summation of effects in the water intake, but not in blood pressure, was also observed when 0.5 M NaCl was infused intravenously in combination with the injection of angiotensin II into the subfornical organ and into the lateral preoptic area. 4. The results indicate that there are interactions between the subfornical organ and lateral preoptic area in the regulation of cardiovascular and thirst mechanisms.

Effect of cobalt(II) oxide and manganese(IV) oxide on sintering of tin(IV) oxide

Additions of 0.5 to 2.0 mol% of CoO or MnO2 onto SnO, promote densification of this oxide up to 99% of theoretical density. The temperature of the maximum shrinkage rate (TM) and the relative density in the maximum densification rate (p*) during constant sintering heating rate depend on the dopant concentration. Thus, dopant concentration controls the densifying and nondensifying mechanisms during sintering. The densification of SnO2 witih addition of CoO or MnO, is explained in terms of the creation of oxygen vacancies.

Effects of the alpha antagonists and agonists injected into the lateral hypothalamus on the water and sodium intake induced by angiotensin II injection into the subfornical organ

The subfornical organ (SFO) and the lateral hypothalamus (LH) have been shown to be important for the central action of angiotensin II (ANG II) on water and salt regulation. Several anatomical findings have demonstrated neural connections between the SFO and the LH. The present experiments were conducted to investigate the role of the α-adrenergic antagonists and agonists injected into the LH on the water and salt intake elicited by injections of ANG II into the SFO. Prazosin (an α1-adrenergic antagonist) injected into the LH increased the salt ingestion, whereas yohimbine (an α2-adrenergic antagonist) and propranolol (a β-adrenergic antagonist) antagonized the salt ingestion induced by administration of ANG II into the SFO. Previous administration of clonidine (an α2-adrenergic agonist) or noradrenaline into the LH increased, whereas pretreatment with phenylephrine decreased the sodium intake induced by injection of ANG II into the SFO. Previous treatment with prazosin and propranolol reduced the water intake induced by ANG II. Phenylephrine increased the dipsogenic responses produced by ANG II, whereas previous treatment with clonidine injected into the LH reduced the water intake induced by ANG II administration into the SFO. The LH involvement with SFO on the excitatory and inhibitory mechanisms related to water and sodium intake is suggested.

Invited review Giardia duodenalis: Inter-strain variability of proteins, antigens, proteases, isoenzymes and nucleic acids

Giardia duodenalis isolates from asymptomatic or symptomatic patients and from animals present similarities and differences in the protein composition, antigenic profile, pattern of proteases and isoenzymes, as well as in nucleic acids analysis. In the present overview, these differences and similarities are reviewed with emphasis in the host-parasite interplay and possible mechanisms of virulence of the protozoon.

The phenomenon of photoinhibition of photosynthesis and its importance in reforestation

Photoinhibition, defined as the inhibition of photosynthesis caused by excessive radiance, affects field production to a great extent. This phenomenon is particularly relevant in reforestation practices, when one deals with forests of rapid growth such as Eucalyptus. The imposition of additional stress factors during exposure to high radiance increases the potential for photoinhibitory effects, so the inhibition of photosynthesis indicates that the plant is submitted to stressful conditions. Photoinhibition can be reversible, playing a protective role for the photosynthetic systems, but it can also reflect damage that has already occurred in the photosynthetic apparatus, being irreversible in this case. In this review, we present the physiological and molecular mechanisms of photoinhibition and discuss the interaction between light and other stress factors and its effects on plants destined for reforestation. In addition, the present work analyzes some of the features and strategies that help plants avoid or restrict the occurrence of photoinhibition. For instance, pigments and enzymes which naturally occur in plants can prevent photoinhibition, while preadaptation to nonideal conditions can enhance tolerance to a certain stress factor. Most of these morphological, metabolic, and biochemical mechanisms of defense are related to the dissipation of excessive energy such as heat. Understanding these mechanisms can help improve cultivation procedures, avoid the plants' death, and increase productivity in the field.

Amphetamine Poisoning in a Dog: Case Report, Literature Review and Veterinary Medical Perspectives

Amphetamine abuse in human beings has increased, resulting in many reports of toxicity and death. In the US over 4 million people have abused amphetamines at least once, thus small animals are exposed to increased accidental poisoning risk. This report describes an acute amphetamine poisoning in a dog due to ingestion of 15 mg/kg fenproporex, leading to typical signs of catecholamines release and effects in different organ systems. Similar clinical and laboratory findings observed in human beings are reviewed and physiopathogenic mechanisms discussed, as well as the therapeutic approaches available in veterinary medicine.

Biomolecular information, brain activity and cognitive functions

Molecular neurobiology has provided an explanation of mechanisms supporting mental functions as learning, memory, emotion and consciousness. However, an explanatory gap remains between two levels of description: molecular mechanisms determining cellular and tissue functions, and cognitive functions. In this paper we review molecular and cellular mechanisms that determine brain activity, and then hypothetize about their relation with cognition and consciousness. The brain is conceived of as a dynamic system that exchanges information with the whole body and the environment. Three explanatory hypotheses are presented, stating that: a) brain tissue function is coordinated by macromolecules controlling ion movements, b) structured (amplitude, frequency and phase-modulated) local field potentials generated by organized ionic movement embody cognitive information patterns, and c) conscious episodes are constructed by a large-scale mechanism that uses oscillatory synchrony to integrate local field patterns. © by São Paulo State University.

Youth and social cohesion in Ibero-America: a model in the making. Summary

Includes bibliography

Road maps towards an information society in Latin America and the Caribbean

Includes bibliography

Ageing, solidarity and social protection in Latin America and the Caribbean: time for progress towards equality

Includes bibliography

Shaping the future of social protection: access, financing and solidarity

Includes bibliography

SMEs in the environmental goods and services market: identifying areas of opportunity, policies and instruments: case studies: Argentina, Chile, Colombia and Mexico

Includes bibliography

Energy efficiency potential in Jamaica: challenges, opportunities and strategies for implementation

Incluye Bibliografía

The current situation of small and medium-sized industrial enterprises in Trinidad & Tobago, Barbados and St. Lucia

Includes bibliography

National mechanism for gender equality and empowerment of women in Latin America and the Caribbean

Incluye Bibliografía