Influence of temperature on the release of plasminogen activator.

Fibrinolysis is a basic defense mechanism of the organism designed to control the deposition of fibrin in the vascular system and elsewhere. Fibrinolytic activity was measured by the fibrin plate method for three groups of rats (N = 6) that were maintained at room temperature, 20-25 degrees C, 3 degrees C or 38 degrees C for 4 h before testing. Based on measurement of fibrinolytic activity, the level of plasminogen activator released from isolated aortic segments of rats maintained at room temperature (24-28 degrees C) differed significantly from that of the 38 degrees C group. The animals maintained at 3 degrees C did not release plasminogen activator, suggesting that the fibrinolytic response was impaired at low temperature.

Papel da regiao AV3V no choque septico experimental em ratos tratados com NaCl 7,5%

The effect of intravenous infusion of hypertonic saline (HS) on the recovery of mean arterial pressure (MAP) during septic shock was studied in sham-operated rats and in rats with electrolytic lesion in the anteroventral third ventricle (AV3V) region. Our results show that intravenous HS infusion in rats treated with endotoxin (Etx) partially restores MAP, but when we have a severe shock produced by Etx, HS was not able to reverse the hypotension. We also show that the integrity of the AV3V region is essential for the protective action of HS in endotoxin shock. It is possible that NO production contributes to the deleterious effect of endotoxin. So, the unraveling of the release of NO by the vascular endothelium and their role as regulators of vascular tone is increasing our understanding of the physiology and pathophysiology of the cardiovascular system and will therefore enhance the possibilities of preventing and treating endotoxin shock.

Tratamento de ulcera varicosa e lesoes de pele com Calendula officinalis L. e/ou com Stryphnodendron barbadetiman (Vellozo) Martius

Calendula officinalis L. and S. barbadetiman are used in Brazil for the treatment of a number of aliments. The healing properties of these substances are well known, mainly in domestic or sun burn. In order to establish a pharmacological rationale for the traditional use of these plants as a cicatrizant or antiinflammatory remedy, we used ethanol extracts or gel from stem bark of the S. barbadetiman and inflorescence of the Calendula. We selected four groups of patients; two groups shown varicose ulcer (I, II) and two groups shown skin lesions (III and IV). Groups I and III were treated with Calendula and group II and IV were treated with Calendula plus barbadetiman. The data in this study suggest that the treatment with Calendula or Calendula plus barbadetiman are effective in the process that brings wounds to a close. These findings provide basis to an alternative treatment of varicose ulcer.

Effect of NωNLA or dexamethasone on vascular hyporeactivity induced by E. coli endotoxin in sham and adrenalectomized rats

Induction of iNOS by bacterial products is considered to be part of the defense mechanism against infection. However, it has been suggested that the bacterial-induced NO-overproduction may be involved in the vascular hyporeactivity and in septic shock. It is well known that glucocorticoids prevent the induction of iNOS by Etx in rats. In the present study, dexamethasone diminished but not abolished Etx-induced vascular hyporeactivity in rats. Our results showed that the inhibition of iNOS protects sham rats against the lethal shock produced by Etx, but, in Adx rats, the NωNLA, an iNOS inhibitor, did not reduce Etx-induced mortality. Interestingly, the lack of glucocorticoid impaired the protective effect of NωNLA against Etx-induced hyporeactivity and shock in rats. A conceivable pharmacological approach to protect tissues against deleterious effect of excessive NO production includes inhibition of the iNOS, because the absence of glucocorticoid may increase the iNOS gene expression, with NO-overproduction induced by Etx, suggesting that the glucocorticoids might be of therapeutic value for the treatment of hyporeactivity and shock triggered by sepsis.

Effect of nωnla, an inhibitor of No-synthase, on the release of tissue-plasminogem activator from rat aorta

Alterations in the synthesis or enhanced inactivation of nitric oxide (NO) and increase in fibrin deposition in the vascular bed lead to an imbalance that can induced intravascular coagulation. NO is produced through L-arginine pathway by constitutive and inducible nitric oxide synthase (NOS). The inducible isoform can be activated by cytokines such as tumor necrosis factor alfa. We evaluated NO-induced tissue-plasminogen activator (t-PA) release from isolated aortic segments of Wistar rats measuring the fibrinolytic activity in the fibrin plate. Inhibition of NO biossynthesis with Nω-nitro-L-arginine (NωNLA) significantly attenuated the fibrinolytic activity (FA) evoked by aortic segments of this group (GII) compared to the saline group (GI). The administration of L-arginine produced restoration of FA in this group (GIII) treated with NωNLA suggesting that t-PA arising from segments of rat aorta is influenced by NO.

Efeito do tratamento com algumas vitaminas B na potencializaçã o do efeito antiinflamatório e antinociceptivo do diclofenaco e da talidomida

The effects of some B vitamins on chemical nociception in mice or paw edema in rats were investigated. A combination of thiamine (B1), pyridoxine (B6) and cyanocobalamin (B12), in doses of 100,100 and 5mg/kg, i.p., respectively, potentiated the inhibition by diclofenac or thalidomide of paw edema induced by carrageenin in rat. Antinociceptive effects of diclofenac and thalidomide inhibition of abdominal contortion were also potentiated by the combination of the vitamins B1, B6 and B12. Thiamine, pyridoxine and cyanocobalamin given singly were effective in potentiating antinociceptive effects of thalidomide, but only cyanocobalamin potentiated these effects of diclofenac, probably reflecting the differing mechanisms of action of the two drugs. The results document the positive influence of B vitamins on antinociceptive effects of diclofenac or thalidomide and support the use of B vitamins to shorten the treatment time and reduce the daily dose of anti-inflammatories.

Vascular hyporeactivity to angiotensin II induced by Escherichia coli endotoxin is reversed by Nω-Nitro-L-Arginine, an inhibitor of nitric oxide synthase

Septic shock or sepsis is reported to be one of the major causes of death when followed by systemic infectious trauma in humans and other mammals. Its development leads to a large drop in blood pressure and a reduction in vascular responsiveness to physiological vasoconstrictors which, if not contained, can lead to death. It is proposed that this vascular response is due to the action of bacterial cell wall products released into the bloodstream by the vascular endothelium and is considered a normal response of the body's defenses against infection. A reduction in vascular reactivity to epinephrine and norepinephrine is observed under these conditions. In the present study in rats, the aim was to assess whether those effects of hypotension and hyporeactivity are also related to another endogenous vasoconstrictor, angiotensin II (AII). We evaluated the variation in the power of this vasoconstrictor over the mean arterial pressure in anesthetized rats, before and after the establishment of hypotension by Escherichia coli endotoxin (Etx). Our results show that in this model of septic shock, there is a reduction in vascular reactivity to AII and this reduction can be reversed by the inhibitor of nitric oxide synthase, Nω-Nitro-L- Arginine (NωNLA). Our results also suggest that other endogenous factors (not yet fully known) are involved in the protection of rats against septic shock, in addition to the L-arginine NO pathway.

Potencialização do efeito antiinflamatório e antinociceptivo do diclofenaco e da nimesulida por vitaminas do complexo B

The effects of a combination of some B vitamins and diclofenac or nimesulide on chemical nociception in mice or paw edema in rats were investigated. While the vitamins alone had no effect, combination of thiamine (B1), pyridoxine (B6) and cyanocobalamin (B12), given i.p. in doses of 100mg and 5mg/kg, respectively, potentiated the inhibition by nimesulide (5mg/kg) of paw edema induced by carrageenin in rats. Antinociceptive effects of diclofenac and nimesulide (inhibition of abdominal writhing induced by acetic acid in mice) were also potentiated by the combination of the vitamins B1, B6 and B12. Thiamine, pyridoxine and cyanocobalamin given singly were effective in potentiating antinociceptive effects of nimesulide, but only cyanocobalamin potentiated these effects of diclofenac, probably reflecting the differing mechanisms of action of the two drugs. The results document the positive influence of B vitamins on the antinociceptive effects of diclofenac or nimesulide and support the use of B vitamins to shorten the treatment time and reduce the daily dose of anti-inflammatories.

Contribuição ao entendimento da patogenia da sepse

The most frequent cause of vasodilatory shockis outcome from sepsis, a systemic inflammatory response to infection, characterized by hypotension, hyporeactivity to the catecholamines and disseminated intravascular coagulation. The commonest cause of sepsis has reported to be infection with Gram-negative bacteria, typically E. coli, resulting in the release of lipopolysaccharide (endotoxin) from the bacterial outer membrane during autolysis or death of these microorganisms, with the involvement of many mediators, including nitric oxide. Later it was found that plasma levels of vasopressin in sepsis patients were abnormally low and observed that some patients with advanced septic shock were extremely sensitive to the activity actions of exogenous vasopressin.

Reação de cultivares de cana-de-açúcar à broca do colmo

The objective of this study was to evaluate the reaction of ten sugarcane cultivars to Diatraea saccharalis under field conditions, using a randomized block design with treatments in factorial 2x10 with six replications. The first factor was represented by two levels of infestation (infested and not infested) by borer and the second one, by the ten sugarcane varieties (IAC87-3396, IAC91-1099, IACSP93-3046, IACSP94-2101, IACSP94-2094, IACSP94-4004, IACSP95-5000, IACSP96-3060, IACSP96-2042 and SP91-1115). The experiment was evaluated in two crop cycles: plant crop and first ratoon. All cultivars were attacked by the borer, being IACSP94-4004, IACSP96-2042 and SP91-1115 the most damaged cultivars with the highest infestation index. During the plant crop, plots infested by the borer presented higher fiber content than the ones not infested. During the first ratoon, non infested plants produced 10% less and presented lower purity and higher content of reducing sugars than the non-infested plants.

O laboratório do artista - cientista

Pós-graduação em Artes - IA

Modelagem matemática em câncer: dinâmica angiogênica e quimioterapia anti-neoplásica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)