Double membrane based on lidocaine-coated polymyxin-alginate nanoparticles for wound healing: In vitro characterization and in vivo tissue repair.

The aim of this study was to develop and characterize a double layer biomembrane for dual drug delivery to be used for the treatment of wounds. The membrane was composed of chitosan, hydroxypropyl methylcellulose and lidocaine chloride (anesthetic drug) in the first layer, and of sodium alginate-polymyxin B sulphate (antibiotic) nanoparticles as the second layer. A product with excellent thickness (0.01-0.02 mm), adequate mechanical properties with respect to elasticity, stiffness, tension, and compatible pH for lesion application has been successfully obtained. The incorporation of the drugs was confirmed analysing the membrane cross-sections by scanning electron microscopy. A strong interaction between the drugs and the functional groups of respective polymers was confirmed by Fourier-Transform Infrared Spectroscopy, thermal analysis and X-ray diffraction. Microbiological assays showed a high antimicrobial activity when polymyxin B was present to act against the Staphylococcus aureus and Pseudomonas aeruginosa strains. Low cytotoxicity observed in a cell viability colorimetric assay and SEM analysis suggest biocompatibility between the developed biomembrane and the cell culture. The in vivo assay allowed visualizing the healing potential by calculating the wound retraction index and by histological analysis. Our results confirm the effectiveness of the developed innovative biomaterial for tissue repair and regeneration in an animal model.

Antibacterial activity of chitosan/collagen membranes containing red propolis extract.

In this study we developed a mucoadhesive polymeric membrane wound dressing incorporating red propolis extract (HERP). Membranes were made using a casting method employing collagen, chitosan, polyethylene glycol (15, 20, and 30v%), and hydroethanolic extract of EtOH-H2O 70v% - 30v% (v/v) of HERP (0.5, 1.0, and 1.5%). Membranes were extensively characterized to assess the thickness, pH, morphology using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), mechanical properties, swelling, in vitro mucoadhesion, cytotoxicity, and minimum inhibitory concentration (MIC). Assessment of the thickness and mechanical properties of the membranes containing HERP revealed that the most significant thickness obtained was 40.7 µm; thermal analysis suggests suggesting the hydrogen bonds between hydroxyl groups of isoflavones and the free amine present in the region of chitosan. Cell viability decreased as the amount of HERP increased. Finally, the MICs were 7.8 and 1.9 µg.mL-1 for Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853, respectively. These results were suggesting that the 0.5 % HERP membrane has the potential for future studies for wound application.

Silver Nanoparticles-Composing Alginate/Gelatine Hydrogel Improves Wound Healing In Vivo.

Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO3 precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430-450 nm in the ultraviolet-visible (UV-Vis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FT-IR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm-1. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.

Chitosan/pvp-based mucoadhesive membranes as a promising delivery system of betamethasone-17-valerate for aphthous stomatitis.

Mucoadhesive membranes were proposed in this study as drug delivery system for betamethasone-17-valerate (BMV) in the treatment of recurrent aphthous stomatitis (RAS). The membranes were obtained by using the polymers chitosan (CHI) in both presence and absence of polyvinilpyrrolidone (PVP), following the solvent evaporation method. The presence of PVP in the membranes causes significant modifications in its thermal properties. Changes in the thermal events at 114 and 193 °C (related to BMV melting point), and losses in mass (39.38 and 30.68% for CH:PVP and CH:PVP-B, respectively), suggests the incorporation of BMV in these membranes. However, the morphological aspects of the membranes do not change after adding PVP and BMV. PVP causes changes in swelling ratios (>80%) of the membranes, and it is suggested that the reorganization of the polymer mesh was highlighted by the chemical interactions between the polymers leading to different percentages of BMV released ∼40% and ∼80% from CH-B and CH:PVP-B. BMV release profile follows Korsmeyer and Peppas model (n > 0.89) which suggests that the diffusion of the drug in the swollen matrix is driven by polymer relaxation. In addition, the membranes containing PVP (higher swelling ability) present high rates of tensile strength, and therefore, higher mucoadhesion. Moreover, given the results presented, the developed mucoadhesive membranes are a promising system to deliver BMV for the treatment of RAS.

Validation of an UV spectrophotometric assay for the quantification of polymyxin B in solid lipid nanoparticles.

Polymyxins are efficient antibiotic drugs used for the treatment of Gram-negative bacterial infections. These compounds are not absorbed in the gastrointestinal tract and are responsible for serious toxicological effects. In order to enhance their therapeutic effectiveness, decrease the adverse/toxic side effects and promote a sustained release profile, a derivative--polymyxin B sulphate--has been formulated in solid lipid nanoparticles (SLNs) intended for buccal administration. To quantify polymyxin B in the formulation, UV spectrophotometry analysis was applied, validating the analytical methodology by assessing the selectivity, accuracy, precision, linearity, and repeatability. Analyses were performed at 210 nm keeping the samples at 25 degrees C. Results showed that lipid composition of SLNs did not interfere with the polymyxin B spectra. The linearity showed a correlation coefficient of 0.9977 in the range of 5-90 µg/mL. Quantification of polymyxin B by UV spectrophotometry, at 210 nm in SLN formulations, was approved in all analyzed parameters, validating the methodology proposed in this work.

Nanoemulsions and nanoparticles for non-melanoma skin cancer: effects of lipid materials

Basal cell carcinomas and squamous cell carcinomas are non-melanoma skin cancers reported to be among the most common malignancies, being responsible for high human morbidity. Conventional chemotherapy applied to these conditions shows non-specific targeting, thus severe adverse side effects are also commonly reported. New therapeutic strategies based on nanoparticulates technology have emerged as alternatives for site specific chemotherapy. Among the different types of nanoparticulates, lipid nanoemulsions and nanoparticles have several advantages for topical delivery of poorly soluble chemotherapeutics. These particles show sustained drug release and protection of loaded drugs from chemical degradation. This technology is promising to enhance the intracellular concentration of drugs and consequently reduce the cytotoxicity of skin chemotherapy (AU)

Nanoemulsions and nanoparticles for non-melanoma skin cancer: effects of lipid materials.

Basal cell carcinomas and squamous cell carcinomas are non-melanoma skin cancers reported to be among the most common malignancies, being responsible for high human morbidity. Conventional chemotherapy applied to these conditions shows non-specific targeting, thus severe adverse side effects are also commonly reported. New therapeutic strategies based on nanoparticulates technology have emerged as alternatives for site specific chemotherapy. Among the different types of nanoparticulates, lipid nanoemulsions and nanoparticles have several advantages for topical delivery of poorly soluble chemotherapeutics. These particles show sustained drug release and protection of loaded drugs from chemical degradation. This technology is promising to enhance the intracellular concentration of drugs and consequently reduce the cytotoxicity of skin chemotherapy.

Avaliação da atividade antimicrobiana de extratos vegetais / Evaluation of the antimicrobial activity of vegetal extracts

Especialmente nas últimas décadas, inúmeros esforços têm sido dirigidos para conferir às plantas seu real papel e valor na terapia. Neste estudo foi avaliada a atividade antimicrobiana de extratos secos de Artemisia absinthium L. (losna), Mentha pulegium L. (poejo), Punica granatum L. (romã), Xanthosema violaceum Schott (taioba) e Syzygium cuminii L. (jambolão). Para avaliar a atividade antimicrobiana foi realizado o teste de difusão em ágar, com 15 diferentes microrganismos, utilizando discos impregnados com as dispersões aquosas dos extratos vegetais. A Concentração Inibitória Mínima (CIM) foi determinada para os extratos que apresentaram atividade inibitória. Os resultados mostraram que os extratos de X. violaceum e S. cuminii inibiram, respectivamente, 8 e 6 bactérias. Conclui-se que os extratos de X. violaceum e S. cuminii são capazes de inibir expressivamente o crescimento microbiano.

In the last decades, innumerable efforts have been directed to confer to the plants its real value in the therapy. The aim of this study was to evaluate the antimicrobial activity of dry extracts of Artemisia absinthium L. (wormwood), Mentha pulegium L. (poejo), Punica granatum L. (pomegranate), Xanthosema violaceum Schott(taro) and Syzygium cuminii L. (jambolan). To evaluate the antimicrobial activity the diffusion test in agar was carried through, with 15 different microorganisms, using discs impregnated with aqueous dispersions of the vegetal extracts. For those extracts that had presented inhibitory activity, the calculation of Minimum Inhibitory Concentration was carried out (CIM). The results had shown that the extracts of X. violaceum and S. cuminii had inhibited 8 and 6 bacteria, respectively. What leads to the conclusion that the extracts of X. violaceum and S. cuminii are capable to inhibit the microbial growth.

Estudo da utilização de antimicrobianos e outros fármacos para distúrbios do trato respiratório em pecientes pediátricos hospitalizados / The study of medication in respiratory and antimicrobian treatment in hospitalized pediatrics patients

O tratamento das doenças respiratórias requerem a utilização de antibióticos, corticosteróides e broncodilatadores. Todavia é desejável que, na pediatria, estas medicações sejam restritas e se utilize uma via de administração confortável. O objetivo deste trabalho foi avaliar a utilização dos medicamentos do trato respiratório e antimicrobianos em pacientes pediátricos hospitalizados, por meio da análise de seus prontuários. Os dados foram coletados durante 120 dias, observando-se os medicamentos prescritos, as doses, as vias de administração e as medidas não farmacológicas prescritas. O critério de inclusão na pesquisa foi estar o paciente internado na pediatria, ter na prescrição um antimicrobiano ou medicamento para o trato respiratório. As análises dos 136 prontuários mostrou que 97,06% continham um antimicrobiano, sendo o mais prescrito ampicilina e o fenoterol e ipratrópio como broncodilatadores. Destaca-se que 21,35% das prescrições apresentaram dosagem abaixo do mínimo e em, 21,89% acima do máximo. Embora em 93,75% dos casos tenha havido prescrição de dieta por via oral, 70,59% dos pacientes tiveram prescrição de medicação por via intravenosa. Esses dados revelam o uso de doses subterapêuticas, prescrição excessiva de antimicrobianos e o uso freqüente da via parenteral que encarecem o tratamento, predispõem ao aparecimento de efeitos indesejáveis como superinfecção, prolongando o tempo de permanência no hospital

Reflexão sobre o ensino farmacêutico / Reflection about pharmaceutical education

Este artigo expressa uma preocupação com o ensino farmacêutico baseado nas novas diretrizes curriculares do Conselho Nacional de Ensino. O passado recente priorizou a formação de recursos humanos para as modalidades em detrimento da área privativa do Farmacêutico, a Farmácia em toda sua abrangência. Para não incorrermos no mesmo erro, é necessário desenvolver competências, que possibilitem ao egresso aplicar o conhecimento técnico-científico no contexto social. As novas diretrizes curriculares encerram o ciclo no qual a formação profissional aparecia com o marco divisório das modalidades análises clínicas e indústria. Modelo no qual se concebia a possibilidade de assistência farmacêutica sem conhecimento integral do medicamento não pode ser repetido por uma formação superficialista, segmentada, repleta de atividades técnicas previsíveis e repetitivas e, sobretudo, se conduzido por pessoas sem o preparo necessário ao ensino da atividade. O retorno às atividades primárias do Farmacêutico deve ser precedido pela formação de recursos humanos específicos para a área, o que não acontecerá a longo prazo

[Neonatal nursing: undergraduate nursing students' knowledge]. / Enfermagem neonatológica: conhecimento de alunos de graduação em Enfermagem.

The present study was carried out at the Municipalities of São Paulo and Guarulhos with undergraduate nursing students and aimed at evaluating their knowledge regarding neonatal nursing and, if necessary, to contribute to the program reformulation. Thus, we would be able to improve nurses knowledge on the full-term new born care. In order to develop a structured questionnaire to be used as an instrument to measure the studied variable, aspects of the theoretical content related to the most common care procedures at the neonatal unit were selected. Authors found that students' theoretical knowledge on the theme was regular.

Regulation by nitric oxide of prostaglandin E synthesis and spontaneous motility in rat uterine tissue.

We explored the role of endogenous nitric oxide (NO) in the spontaneous motility of uterine tissue from pseudopregnant (psp) rats and the correlation between this action and the uterotonic prostaglandin (PG) E production. We worked in the early psp (on day 5 of psp), and in late psp (on day 8 and day 9). Treatment with N(G)-monomethyl-L-arginine L-NMMA (300 microM), a competitive nitric oxide synthase (NOS) inhibitor, did not modify isometric developed tension (IDT) and frequency of contractions (FC) on day 5 of psp; on day 8, tissue pretreated with L-NMMA showed an increase in the IDT and FC compared with controls, while on day 9 of psp, both IDT and FC showed a lower stability after treatment with the inhibitor. These data suggest that NO modulates uterine motility on day 8 (decreasing it) and on day 9 of psp (enhancing it). We also evaluated the total NOS activity and that of its isoforms at the three times mentioned, demonstrating that total NOS activity was higher on day 5 of psp and decreased with psp development. On day 5 of psp, calcium-dependent and calcium-independent NOS each forms around 50% of total NOS activity. On day 8 of psp, the calcium-dependent was the predominant NOS form, while on day 9 of psp, the uterine tissue showed a higher calcium-independent form of the enzyme. In view of the fact that we found an inhibitor effect of the endogenous NO in uterine contractility on day 8 of psp and an inverse action on day 9 of psp (enhancing uterine contractility), we suggest that the NOS calcium-dependent form could be responsible for uterine contractility in psp rats. Finally, we evaluated the relationship between endogenous NO and PGE production. We observed that on days 5 and 8 of psp, the L-NMMA (300 microM) treatment did not affect PGE production, but on day 9 of psp, the preincubation with the NOS inhibitor diminished PGE synthesis, suggesting that at this time endogenous NO can upregulate uterine PGE production. These results confirm that NO can modulate uterine motility by means of PGE production. In summary, we suggest that in uterine tissue from psp rats, the NO system can alternatively decrease or increase uterine contractions, this last effect by enhancing uterine PGE synthesis.

Nitric oxide mediates platelet-activating factor stimulatory action on uterine prostaglandin production.

Accumulated evidence suggests that platelet-activating factor (PAF) may have a role in implantation by stimulating prostaglandin (PG) production. Since we had demonstrated that nitric oxide (NO) can increase uterine PGs, the aim of this study was to explore whether or not NO could mediate rat uterus responses to PAF on day 5 of gestation, when implantation takes place. Uterine motility was enhanced by PAF as compared to controls. This action was abolished by either the arginine analogue, N-monomethyl L-arginine (L-NMMA) or the cyclooxygenase inhibitor, indomethacin. On the other hand, NOS activity was detected in uterine strips and could be stimulated by PAF. The cyclooxygenase product PGE2 was also significantly stimulated by PAF. Inhibition of endogenous NO formation abolished the PAF effect on PG synthesis. Our results suggest that NO is an important intermediate in the interaction between PAF and PGs.

Role of nitric oxide on oxytocin-evoked contractions and prostaglandin synthesis in isolated pregnant rat uterus.

Uterine contractions elicited by oxytocin (OT), possibly linked with uterus prostaglandin (PG) release, are involved in the final pathway of labor. It is known that nitric oxide (NO) may contribute to the maintenance of uterine contractile quiescence during gestation. Therefore in this study the effect of the inhibition of NO synthase (NOS), with N-monomethyl L-arginine (L-NMMA), on the ability of OT to stimulate uterine contractions and PG synthesis was investigated in isolated rat uterus at days 13 and 21 of pregnancy. L-NMMA did not modify the frequency and the force of contractions elicited by OT at day 13. On day 21 the frequency of contractions evoked by OT were better sustained in the presence of L-NMMA. PGs were not affected by OT on day 13. OT stimulated PGF2alpha on day 21 when NOS had been inhibited with L-NMMA, but not in the absence of L-NMMA. NOS activity was stimulated by OT at day 21 of gestation. In summary these findings indicate that near term NO can regulate OT PGF2alpha induced contractions and PG synthesis in isolated pregnant rat uterus.

Nitric oxide in the contractile action of bradykinin, oxytocin, and prostaglandin F2 alpha in the estrogenized rat uterus.

Experiments were performed on uteri from estrogen-primed female rats. Bradykinin (BK) (10(-8) M) significantly augmented biosynthesis of prostaglandin F2 alpha (PGF2alpha) and prostaglandin E2 (PGE2), and this synthesis was completely blocked by NG-monomethyl L-arginine (NMMA) (300 microM), a competitive inhibitor of nitric oxide synthase (NOS). Blockade of prostaglandin synthesis by indomethacin caused rapid dissipation of isometric developed tension (IDT) induced by BK. Blockade of NOS with NMMA had similar but less marked effects. Combining the two inhibitors produced an even more rapid decay in IDT, suggesting that BK-induced NO release maintains IDT by release of prostanoids. The decline of frequency of contraction (FC) was not significantly altered by either indomethacin or NMMA but was markedly accelerated by combination of the inhibitors, which suggests that PGs maintain FC and therefore FC decline is accelerated only when PG production is blocked completely by combination of the two inhibitors of PG synthesis. The increase in IDT induced by oxytocin was unaltered by indomethacin, NMMA or their combination indicating that neither NO nor PGs are involved in the contractions induced by oxytocin. However, the decline in FC with time was significantly reduced by the inhibitor of NOS, NMMA, suggesting that FC decay following oxytocin is caused by NO released by the contractile process. In the case of PGF2alpha, NMMA resulted in increased initial IDT and FC. The decline in FC was rapid and dramatically inhibited by NMMA. Receptor-mediated contraction by BK, oxytocin, and PGF2alpha is modulated by NO that maintains IDT by releasing PGs but reduces IDT and FC via cyclic GMP.

Distribution of neuronal and non-neuronal NADPH diaphorases and nitric oxide synthases in rat uterine horns under different hormonal conditions.

Since pharmacological evidence indicates that nitric oxide (NO) operates in the control of uterine motility, we have studied the distribution of NADPH diaphorase and NO synthases in the rat uterus using histochemical and immunohistochemical methods. Numerous nerve fibers displayed NADPH diaphorase activity and immunoreactivity to antisera raised against neuronal NO synthase. Nerve fibers appeared in all stages of the estrous cycle and also after ovariectomy. NADPH diaphorase activity was also present in endothelia and cells dispersed in the different uterine layers. Most NADPH diaphorase-positive (ND) cells had eosinophilic granules with occasional cells expressing the ED1 macrophage-monocyte marker. Immunoreactivity for an inducible NO synthase was found in a small number of macrophage-like cells without NADPH diaphorase activity. Thus, ND cells may express another NO synthase isoform not detected by the available antisera. In normal cycling rats, ND cells were most abundant during proestrus, and their number further increased after estrogen treatment. ND cells were not observed after ovariectomy but were present after estrogen replacement therapy. ND cells could be involved in the estrogenic control of in vivo and in vitro uterine.

Synthesis and release of prostaglandins D2 and E2 by rat uterine tissue throughout the sex cycle. Effects of 17-beta-estradiol and progesterone.

The synthesis and release of prostaglandins (PGs) D2 and E2 by rat uterine tissue was studied during the whole sex cycle. The PGs released into the bathing solution after 60 min of incubation were measured by specific radioimmunoassays. It was found that PGD2 released at diestrous was significantly higher than at proestrous and estrous. We also observed that PGE2 produced at diestrous was significantly higher than at proestrous and estrous, i.e. both PGs follow the same pattern of production throughout the sex cycle, but in all cases the uterine strips released higher amounts of PGE2 than of PGD2. The influence of the sex hormones on PGD2 and PGE2 synthesis, was also studied. We observed that the treatment of ovariectomized rats with 17-beta-estradiol decreased significantly the synthesis and release of PGD2 and PGE2. On the other hand, progesterone treatment did not modify the production of PGE2 but decreased significantly the synthesis of PGD2. In conclusion, in the present study we have found that PGD2 and PGE2 production varied similarly during the sex cycle and that 17-beta-estradiol negatively regulates their synthesis. In addition, we have found that progesterone depressed only PGD2 synthesis without affecting PGE2 production.

Role of nitric oxide in eicosanoid synthesis and uterine motility in estrogen-treated rat uteri.

Cholinergic stimulation of vascular endothelin activates NO synthase (NOS), leading to generation of NO from arginine. This NO diffuses to the overlying vascular smooth muscle and causes vasodilatation. NOS has also been found in the central and peripheral nervous systems and it is clear now that NO plays an important role as a neurotransmitter. Here we investigate the role of NO in controlling contraction of uterine smooth muscle. Our previous work showed that NO activates the cyclooxygenase enzyme in the hypothalamus, leading to production of prostaglandin E2 (PGE2). We began by determining whether NO was involved in production of arachidonic acid metabolites in the uterus. Uteri were removed from female rats that had been treated with estrogen (17 beta-estradiol). Control animals were similarly injected with diluent. Tissues were incubated in vitro in the presence of [14C]arachidonic acid for 60 min. Synthesis of PGs and thromboxane B2 (TXB2) was markedly stimulated by sodium nitroprusside (NP), the releaser of NO. The effect was greatest on TXB2; there were no significant differences in increases of different PGs. The response to NP was completely prevented by Hb, a scavenger of NO. The inhibitor of NOS, NG-monomethyl-L-arginine (NMMA), significantly decreased synthesis of PGE2 but not the other prostanoids (6-keto-PGF1 alpha and PGF2 alpha). Addition of Hb to scavenge the spontaneously released NO inhibited synthesis of 6-keto-PGF1 alpha, PGE2, and PGF2 alpha, but not TXB2. There was a much lesser effect on products of lipoxygenase, such that only 5-hydroxy-5,8,11,14-eicosatetraenoic acid (5-HETE) synthesis was increased by NP, an effect that was blocked by Hb; there was no effect of NMMA or Hb on basal production of 5-HETE. Thus, NO stimulates release of the various prostanoids and 5-HETE; blockade of NOS blocked only PGE2 release, whereas Hb to scavenge the NO released also blocked synthesis of 6-keto-PFG1 alpha, PGE2, and PGF2 alpha, indicating that basal NO release is involved in synthesis of all these PGs, especially PGE2. Presumably, NMMA did not block NOS completely, whereas Hb completely removed released NO. This may explain the different responses of the various prostanoids to NMMA and Hb. To determine the role of these prostanoids and NO in control of spontaneous in vitro uterine contractility in the estrogen-treated uterus, the effect of blocking NOS with NMMA and of scavenging NO produced by Hb on the time course of spontaneous uterine contractility was studied. Surprisingly, blockade of NOS or removal of NO by Hb prevented the spontaneous decline in uterine motility that occurs over 40 min of incubation. We interpret this to mean that NO was released in the preparation and activated guanylate cyclase in the smooth muscle, resulting in production of cGMP, which reduces motility and induces relaxation. When the motility had declined to minimal levels, the effect of increased NO provided by NP was evaluated; apparently by stimulating the release of prostanoids, a rapid increase in motility that persisted for 10 min was produced. This effect was completely blocked by Hb. The action of NO was also blocked by indomethacin, indicating that it was acting via release of PGs. Apparently, when motility is low, activation of PG synthesis by NO to activate the cyclooxygenase enzyme causes a rapid induction of contraction, whereas, when motility is declining, NO acts primarily via guanylate cyclase to activate cGMP release; the action of the prostanoids released at this time is in some manner blocked.

Acute effects of a single ethanol injection on in vitro rat uterine spontaneous motility, on uteri prostaglandin production and on tissue metabolism of triglycerides.

The acute effects of ethanol (ETOH), injected at 3 g.kg-1i.p. on spontaneous contractions, on prostaglandin (PG) production and on the metabolism of triglycerides (TGs), have been studied in uterine strips obtained from rats at diestrus and suspended in glucose-containing or glucose-free solution. The absolute values of isometric developed tension (IDT: expressed in mg) recorded at 0 time (initial or post isolation determinations) and the frequency of contraction (FC), expressed as the number of contraction cycles during 20 min, were similar for uterine strips from controls and from ETOH treated rats. The uterine IDT and the FC expressed as percent changes from internal controls (0 time values) were explored during 180 min in uteri suspended in glucose medium. The magnitude of IDT decreased, as time progressed, both in controls as well as in ETOH-treated rats. Afterwards, uterine strips from controls exhibited a partial recovery of their contractile activity. This pattern of recovery was not observed in uterine strips from ETOH-treated rats. The uterine IDT, in the ETOH-injected animals after 180 min of activity, were significantly smaller than those of controls. On the other hand, the FC decreased progressively up to the end of the experimental period both in controls as well as in ETOH-treated rats. In glucose-free medium, the IDT of uterine strips from ETOH-injected animals diminished significantly more than controls from 100-180 min following isolation and mounting. In addition, the FC of uterine strips from the ETOH group of rats were significantly smaller than in controls suspended in glucose-free solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of exogenous phospholipase A2 and triacylglycerol lipase on the synthesis and release of monoenoic and bisenoic prostaglandins from isolated rat uterus.

The possible existence of a selective and independent mechanism subserving the formation of prostaglandin E1 (PGE1) and of prostaglandin E2 (PGE2) has been reported in previous studies from our group. In the present experiments we have demonstrated that neutral lipid lipases play an important role yielding dihomo-gamma-linolenic acid for the formation of PGE1. Indeed, exogenous triglyceride lipase added to the incubation bathing solution at a concentration of 150 U/ml increased several fold the production of PGE1 by isolated uterine strips obtained from spayed rats. Nevertheless the presence of the enzyme did not modify significantly the synthesis and release of bisenoic PGs (PGE2 and PGF2 alpha). When triarachidonin was added, as an artificial substrate into the incubating medium in order to detect the presence of endogenous triacylglycerol lipase, we observed a significant increment in the generation of PGE2 (p less than 0.005) and of PGF2 alpha (p less than 0.001) without evident changes in the basal release of PGE1. On the other hand, the addition of phospholipase A2 (PLA2) at 0.2 U/ml, increased significantly the production of PGE2 (p less than 0.001) but failed to alter the concentration of PGE1 in the incubating solution. Surprisingly, PLA2 did not enhance the synthesis of PGF2 alpha in the present experiments, a situation for which we do not have a clear explanation. Exogenous bradykinin (10(-6) M), a well known stimulant of PLA2 activity in several tissues, also increased significantly (p less than 0.001) the production of PGE2 without altering that of PGE1.(ABSTRACT TRUNCATED AT 250 WORDS)