FIA-coupled spectrophotometric method for determination of Cr (VI) traces in natural waters: application of in-line dissolution of 1,5-diphenylcarbazide after heat treatment and activated alumina as adsorbent for preconcentration.

This work proposes the quantification of Cr (VI) ions in natural waters in trace level, using activated alumina (Al2O3) as preconcentration support, controlled in-line dissolution of the solidified chromophore diphenylcarbazide after heat treatment and spectrophotometric detection. The manifold ensures high sensitivity of analytical response, good repeatability, and stability. In this work, optimization of experimental conditions of a flow injection system was chosen as the parameters for greater sensitivity and better selectivity. The selected optimized conditions were 0.30 mol L-1 for H2SO4 concentration, system flow rate as 0.40 mL min-1, sample injection volume of 192.50 µL, 2 min for preconcentration time, and 0.10 mol L-1 for eluent concentration. The analytical curves obtained for real sample analysis show linear range from 0.192 to 0.961 µM, linear correlation coefficient R = 0.9997 and LOD = 0.024 µM. The preconcentration factor of about four times was obtained through the passage of 800 µL of a standard solution containing 0.961 µM of Cr (VI) through mini-column of preconcentration followed by elution at 192.5 µL of NH4OH 0.1 mol L-1 solution. The solid chromogenic reagent presented high durability (weeks in daily use with mass of 0.0993 g) and good reproducibility in analytical signal. The reactivation of the mini-column of alumina should be executed after ten injections of eluent, using 800 µL of HCl 0.02 mol L-1 solution in flow through the same. Each cycle of injection and elution of the sample takes about 5 min on the proposed terms. Despite the length of each cycle still be high, low concentrations can be detected using a technique of relatively low cost. This is due in part, the association dissolution of the chromogenic reagent directly in the line and the preconcentration step. Another important factor is the economy of reagent chromogenic, low generation of reject contributing to better quality of the environment, and the high potential for applications to work in field.

Production and characterization of natural rubber-Ca/P blends for biomedical purposes.

This study presents the development of natural rubber-Ca/P blends, as promising candidates for biomedical purposes. The specific objective was the incorporation of Ca/P into a natural rubber polymeric matrix. Ca/P crystalline phases were synthesized by the sol-gel method and the polymeric matrices were produced using natural rubber extracted from latex of the Hevea brasiliensis. The shape and size of natural rubber particles present in the NR membrane, as well as, the way the Ca/P powder grains aggregate in the polymeric matrix were investigated, giving information about the interactions between the Ca/P and the natural rubber particles. Confocal fluorescence scanning microscopy measurements allowed us to propose a structure where the Ca/P grains are surrounded by natural rubber particles. This structure may mediate Ca(2+) release for tissue regeneration. The system investigated may open new horizons for development of a bandage which provides the controlled-release of biomaterials.

Eficiência nutricional do Nitrogênio e produção de biomassa em Calendula officinalis L. (Asteraceae) em condições de casa de vegetação / Nitrogen nutritional efficiency and biomass production in Calendula officinalis L. (Asteraceae) under greenhouse conditions

O objetivo deste trabalho foi avaliar o efeito da aplicação de diferentes doses de nitrogênio no solo e de épocas de coleta sobre a eficiência nutricional do nitrogênio e a produção de biomassa em Calendula officinalis L. (Asteraceae) em condições de casa de vegetação. O substrato utilizado foi a camada de 0 - 20 cm de Latossolo Vermelho Distroférrico. O delineamento experimental foi inteiramente casualizado, com quatro repetições. Os tratamentos foram constituídos de quatro doses de N (0, 21, 42 e 84mg dm-3) e cinco épocas de colheita (15, 30, 45, 60 e 90 dias após o transplante). O teor de N na inflorescência de calêndula reduziu com as épocas de coleta, redução essa que ocorreu possivelmente devido à menor eficiência da absorção desse elemento pela planta e menor translocação do N para as inflorescências. Pode se concluir que as épocas de avaliação influenciaram na resposta da planta à eficiência de absorção (EFA), sendo a máxima EFA de N aos 51 dias após o transplante das mudas. Observou-se aumento na translocação de N da parte aérea (folhas e caules) para as inflorescências, tendo como consequência a redução do N na parte aérea. Houve incremento na produção de biomassa de calêndula em função das épocas de coleta , e do aumento das doses de N aplicadas no solo. A eficiência nutricional do N foi influenciada pelas épocas de avaliação e pelo teor de N presente no solo.

The aim of this study was to evaluate the effect of both the application of different nitrogen levels on the soil and the harvest periods on nitrogen nutritional efficiency and biomass production in Calendula officinalis L. (Asteraceae) under greenhouse conditions. The employed substrate was 0-20cm layer of Oxisol. Experimental design was completely randomized, with four replicates. Treatments consisted of four N levels (0, 21, 42 and 84 mg dm-3) and five harvest periods (15, 30, 45, 60 and 90 days after transplanting). N levels in Calendula officinalis inflorescences reduced with the harvest periods, and such a reduction was probably due to the lower efficiency of absorption of this element by the plant and to the lower N translocation to inflorescences. We can conclude that the evaluation periods influenced the response of plants to uptake efficiency (UE), and the maximal UE for N was found at 51 days after transplanting of seedlings. There was an increase in N translocation from the shoot (leaves and stems) to inflorescences, which has as consequence N reduction in the shoot. Calendula officinalis biomass production increased with the harvest periods and with the increase in the N levels applied on the soil. N nutritional efficiency was influenced by both the evaluation periods and the N levels present on the soil.

Tolerance to the cataleptic effect that follows repeated nitric oxide synthase inhibition may be related to functional enzymatic recovery.

Systemic or intra-striatal acute administration of nitric oxide synthase (NOS) inhibitors causes catalepsy in rodents. This effect disappears after sub-chronic treatment. The aim of the present study was to investigate if this tolerance is related to changes in the expression of NOS or dopamine-2 (D2) receptor or to a recovery of NOS activity. Male albino Swiss mice (25-30 g) received single or sub-chronic (once a day for 4 days) i.p. injections of saline or L-nitro-arginine (L-NOARG, 40 mg/kg), a non-selective inhibitor of neuronal nitric oxide synthase (nNOS). Twenty-four hours after the last injection, the animals were killed and their brains were removed for immunohistochemistry assay to detect the presence of nNOS or for 'in-situ' hybridisation study using (35)S-labeled oligonucleotide probe complementary to D2 receptor mRNA. The results were analysed by computerised densitometry. Independent groups of animals received the same treatment, but were submitted to the catalepsy test and had their brain removed to measure nitrite and nitrate (NOx) concentrations in the striatum. Acute administration of L-NOARG caused catalepsy that disappeared after sub-chronic treatment. The levels of NOx were significantly reduced after acute L-NOARG treatment. The decrease in NOx after drug injection suffered a partial tolerance after sub-chronic treatment. The catalepsy time after acute or sub-chronic treatment with L-NOARG was negatively (r = -0.717) correlated with NOx levels. Animals that received repeated L-NOARG injections also showed an increase in the number of nNOS-positive neurons in the striatum. No change in D2 receptor mRNA expression was found in the dorsal striatum, nucleus accumbens and substantia nigra. Together, these results suggest that tolerance to L-NOARG cataleptic effects do not depend on changes in D2 receptors. They may depend, however, on plastic changes in nNOS neurons resulting in partial recovery of NO formation in the striatum.

Heparin and hyperbaric oxygenation in enteric autonomic neuron preservation for transplant.

BACKGROUND: Previous studies have suggested that the addition of heparin to a preservation solution attenuated the autonomic dysfunction observed in rat jejunum and in addition that hypothermic hyperbaric oxygenation may play a role as a preservation technique. However, these studies did not address the lesion indices of the autonomic enteric neurons. We sought to investigate whether the autonomic enteric neurons are injured during cold ischemic preservation and whether administration of heparin or hyperbaric oxygenation prevents this lesion. METHODS: Jejunal segments (2 cm; n = 20) of Wistar rats (12-16 weeks old) were maintained in lactated Ringer's solution without or with heparin (H- and H+, respectively) at 4 degrees C under normobaric conditions. Other jejunal segments (n = 10) were maintained at 4 degrees C in H- under hyperbaric oxygenation conditions (HBO). After preservation for 12 hours, H-, H+, and HBO preparations fixed in 10% formaldehyde were stained with hematoxylin and eosin. The lesion indices were expressed as the mean number of affected neurons (karyorhexis, nuclear dislocation, cytoplasmic vacuolisation) per 100 neurons present in intramural ganglia. Statistical analysis was performed using the Mann-Whitney test (P < .05). RESULTS: The histologic studies showed that enteric autonomic neurons were damaged in H- jejunal segments. The lesion indices observed were: karyorhexis 90/100, nuclear dislocation 85/100, and cytoplasmic vacuolization 82/100. The autonomic neurons in H+ and HBO segments seemed to be normal and significantly well-preserved (P < .001). CONCLUSION: Hypothermic hyperbaric oxygenation and heparin prevented lesions in cold ischemic preservation of enteric autonomic neurons.

Inspirometria de incentivo e breath stacking: repercussões sobre a capacidade inspiratória em indivíduos submetidos à cirurgia abdominal / Incentive spirometry and breath stacking: effects on the inspiratory capacity of individuals submitted to abdominal surgery

CONTEXTUALIZAÇÃO: As complicações respiratórias são as principais causas de aumento da morbidade e da mortalidade em indivíduos submetidos à cirurgia de andar superior do abdômen. A eficácia dos procedimentos fisioterapêuticos precisa ser melhor definida, assim como é necessário o conhecimento da melhor estratégia terapêutica a ser implementada. OBJETIVO: Comparar o volume inspiratório mobilizado durante a técnica de breath stacking, com o volume na inspirometria de incentivo em pacientes submetidos à cirurgia abdominal. MATERIAIS E MÉTODOS: Doze pacientes, no primeiro dia de pós-operatório, foram orientados a inspirar profundamente por meio do inspirômetro de incentivo Voldyne® e a realizar esforços inspiratórios sucessivos pela máscara facial adaptada para realização da manobra de breath stacking. Cada técnica foi realizada cinco vezes de acordo com a randomização. No período pré-operatório, os pacientes realizaram prova espirométrica, foram avaliados e instruídos quanto à realização das técnicas. Um ventilômetro de Wright® permitiu o registro da capacidade inspiratória. RESULTADOS: A capacidade inspiratória foi significativamente maior durante o breath stacking do que durante a inspirometria de incentivo, tanto no pré quanto no pós-operatório. Houve redução significativa dos volumes após o procedimento cirúrgico, independentemente da técnica realizada. CONCLUSÕES: A técnica de breath stacking mostrou-se eficaz e superior à inspirometria de incentivo para a geração e sustentação de volumes inspiratórios. Por não haver descrição de efeitos adversos, essa técnica pode, provavelmente, ser utilizada de forma segura e eficaz, principalmente em pacientes pouco cooperativos.

BACKGROUND: Respiratory complications are the main causes of increased morbidity and mortality in individuals who undergo upper abdominal surgery. The efficacy of physical therapy procedures needs clarification, and it is necessary to know which therapeutic approaches are the best ones to implement. OBJECTIVE: To compare the inspiratory volume during the breath stacking maneuver with the volume during incentive spirometry, in abdominal surgery patients. METHODS: Twelve patients, on their first postoperative day, were instructed to take a deep breath through the VoldyneTM incentive spirometer and to make successive inspiratory efforts using a facemask that had been adapted for performing the breath stacking maneuver. Each technique was performed five times according to the randomization. Before the operation, the patients performed a spirometric test. They were also assessed and instructed about the procedures. A WrightTM ventilometer allowed inspiratory capacity to be recorded. RESULTS: The inspiratory capacity during breath stacking was significantly higher than during incentive spirometry, both before and after the operation. There was a significant reduction in volumes after the surgical procedure, independent of the technique performed. CONCLUSIONS: The breath stacking technique was shown to be effective. This technique was better than incentive spirometry for generating and sustaining inspiratory volumes. Since no adverse effects have been described, this technique can probably be used safely and effectively, particularly in uncooperative patients.

Use of hyperbaric oxygenation in small bowel preservation for transplant.

INTRODUCTION: The aim of this work was to study the effects of hyperbaric oxygenation as a preservation technique for small bowel transplantation. METHODS: Twenty 2-month-old male Wistar rats weighting 250 g were divided into two groups: group A (n = 10) in which the small bowel was preserved for 12 hours, and group B (n = 10) in which the small bowel was preserved for 24 hours. After vascular and intraluminal perfusion, 3-cm segments were maintained in Ringer's solution at temperatures between 2 degrees C to 4 degrees C and in normobaric O2 conditions (groups A1, B1) or conditioned in an hyperbaric O2 metal chamber (100% oxygen at 5.5 absolute atmospheres) (groups A2, B2). After this preservation time, we studied intestinal tissue injury and morphometric analysis of the villi. RESULTS: Mucosal injury was significantly greater among group A1 compared to group A2 animals. The grade of the lesions was greater among group B1 compared to group B2 animals. Group A1 showed no difference from Group B1. For lesion grade, the range was smaller in group A2 and group B2 animals. The villi height was significantly smaller in groups A1 and B1 compared to the other groups; whereas it was higher in group A2 as compared with B2. CONCLUSION: Hyperbaric oxygenation may play a role as a preservation technique. Further research is necessary.

Apoptosis and nuclear proliferation in rat small bowel submitted to hypothermic hyperbaric oxygenation for preservation.

UNLABELLED: This study was conducted to assess apoptosis and nuclear proliferation in rat small bowel submitted to hypothermic hyperbaric oxygenation for preservation. METHODS: Twenty two-month-old, male Wistar rats, weighing 250 g were divided into two groups: group I (n = 10), in which the small bowel was preserved for 12 hours, and group II (n = 10) in which the small bowel was preserved for 24 hours. After vascular and intraluminal perfusion, 3-cm segments were maintained in Ringer's solution at 2 degrees to 4 degrees C under normobaric conditions (groups Ia and IIa) or conditioned in a small hyperbaric metal chamber with 100% oxygen at 5.5 absolute atmospheres (groups Ib and IIb). After 12 or 24 hours, apoptotic and mitotic indices were evaluated by immunohistochemical methods. RESULTS: The apoptotic index was significantly higher in small bowel segments in groups Ia and IIa compared with groups Ib and IIb. The mitotic index was significantly higher among group IIb. CONCLUSION: Hypothermic hyperbaric oxygenation reduced intestinal epithelial apoptosis and increased nuclear proliferation during rat small bowel preservation.

A novel system for organ and tissues preservation: the refrigerating hyperbaric chamber.

UNLABELLED: This study was designed to investigate the feasibility of building a simple and inexpensive device to preserve organs or tissues in hyperbaric and hypothermic conditions. METHODS: The device was built on a 40-cm wide, 28-cm long, and 23-cm deep stainless steel chassis. The pressure vessel was built by a 7.8-cm bore stainless steel cylinder put inside another 12-cm cylinder welded together and closed by a steel plate on the top and bottom. The inferior plate was welded, and the superior one was fixed by manual clasp nut. The cooling system is made up of air compressor, condenser, expansion area, and cooling worm that is located between the cylinders. The temperature-controlling device is a computer processor contained in an integrated-circuit chip, with a on-off system to maintain the chamber temperature between 2 degrees to 4 degrees C. The compression of the chamber is performed by lateral coupling with the oxygen cylinder and is maintained at 5.5 absolute atmospheres and controlled by air pressure gauge. The maximal work pressure was evaluated by spreadsheet. Temperature or pressure changes were evaluated by 12- and 24-hour assays. RESULTS: The maximal work pressure permitted was 6.5 absolute atmospheres. Thus, the container was free from danger. The temperature inside the chamber was kept between 2 degrees and 4 degrees C. The production costs of the prototype was US$1000. DISCUSSION: The manufacture of the refrigerating hyperbaric chamber is viable, simple, and inexpensive.

Cannabidiol, a Cannabis sativa constituent, as an antipsychotic drug.

A high dose of delta9-tetrahydrocannabinol, the main Cannabis sativa (cannabis) component, induces anxiety and psychotic-like symptoms in healthy volunteers. These effects of delta9-tetrahydrocannabinol are significantly reduced by cannabidiol (CBD), a cannabis constituent which is devoid of the typical effects of the plant. This observation led us to suspect that CBD could have anxiolytic and/or antipsychotic actions. Studies in animal models and in healthy volunteers clearly suggest an anxiolytic-like effect of CBD. The antipsychotic-like properties of CBD have been investigated in animal models using behavioral and neurochemical techniques which suggested that CBD has a pharmacological profile similar to that of atypical antipsychotic drugs. The results of two studies on healthy volunteers using perception of binocular depth inversion and ketamine-induced psychotic symptoms supported the proposal of the antipsychotic-like properties of CBD. In addition, open case reports of schizophrenic patients treated with CBD and a preliminary report of a controlled clinical trial comparing CBD with an atypical antipsychotic drug have confirmed that this cannabinoid can be a safe and well-tolerated alternative treatment for schizophrenia. Future studies of CBD in other psychotic conditions such as bipolar disorder and comparative studies of its antipsychotic effects with those produced by clozapine in schizophrenic patients are clearly indicated.

Cannabidiol, a Cannabis sativa constituent, as an antipsychotic drug

A high dose of delta9-tetrahydrocannabinol, the main Cannabis sativa (cannabis) component, induces anxiety and psychotic-like symptoms in healthy volunteers. These effects of delta9-tetrahydrocannabinol are significantly reduced by cannabidiol (CBD), a cannabis constituent which is devoid of the typical effects of the plant. This observation led us to suspect that CBD could have anxiolytic and/or antipsychotic actions. Studies in animal models and in healthy volunteers clearly suggest an anxiolytic-like effect of CBD. The antipsychotic-like properties of CBD have been investigated in animal models using behavioral and neurochemical techniques which suggested that CBD has a pharmacological profile similar to that of atypical antipsychotic drugs. The results of two studies on healthy volunteers using perception of binocular depth inversion and ketamine-induced psychotic symptoms supported the proposal of the antipsychotic-like properties of CBD. In addition, open case reports of schizophrenic patients treated with CBD and a preliminary report of a controlled clinical trial comparing CBD with an atypical antipsychotic drug have confirmed that this cannabinoid can be a safe and well-tolerated alternative treatment for schizophrenia. Future studies of CBD in other psychotic conditions such as bipolar disorder and comparative studies of its antipsychotic effects with those produced by clozapine in schizophrenic patients are clearly indicated.

Dopamine and nitric oxide interaction on the modulation of prepulse inhibition of the acoustic startle response in the Wistar rat.

RATIONALE: The nitric oxide (NO)-arginine pathway is intimately connected to the release of dopamine (DA), a neurotransmitter system that may be dysfunctional in schizophrenia. Both schizophrenic patients and rats treated with DA agonists present deficits in sensorimotor gating measured by prepulse inhibition (PPI). OBJECTIVE: Our aim was to investigate the interaction between a NO synthase inhibitor, N(G)-nitro-L-arginine (L-NOARG), and the DA agonists, amphetamine (Amph), apomorphine (Apo), bromocriptine (BRC), quinpirole (QNP) and SKF38393, on the modulation of the PPI. METHODS: Male Wistar rats received two injections of either L-NOARG (40 mg/kg, i.p.) or saline, 1 h before the test, and the DA agonists or vehicle. Testing began 5 min after treatment with Amph (2 mg/kg, i.p.), Apo (0.5 mg/kg, s.c.) or QNP (0.3 mg/kg and 1.0 mg/kg, s.c.), 120 min after BRC (1 and 40 mg/kg, i.p.) and 15 min after SKF38393 (10 mg/kg, s.c.). The PPI test consisted of 60 presentations divided into pulse (100 dB), prepulse (65, 70, 75 and/or 80 dB) and prepulse + pulse. RESULTS: L-NOARG prevented the PPI disruption caused by Amph (2 mg/kg). Apo, QNP and BRC disrupted PPI, but these effects were not significantly changed by L-NOARG. SKF38393 had no significant effect on PPI whether or not preceded by L-NOARG. CONCLUSIONS: Our findings show that L-NOARG interacted with Amph, an indirect DA agonist, but not with the direct DA agonists on PPI, suggesting that NO is involved on the dopaminergic modulation of sensorimotor gating, probably by a presynaptic mechanism.

Comparison between two models of experimental anxiety in healthy volunteers and panic disorder patients.

To further investigate the role of serotonin (5-HT) in anxiety, two tests were used in human subjects. The first was the conditioning of skin conductance response (CSCR) that associates a tone to a loud noise. The second was simulated public speaking (SPS), which is believed to represent unconditioned fear. In healthy volunteers the 5-HT(2A) receptor blocker and 5-HT reuptake inhibitor nefazodone reduced subjective anxiety and the number of spontaneous fluctuations of skin conductance during CSCR, but enhanced anxiety induced by SPS. Opposite effects had been reported with the 5-HT releasing and uptake-inhibiting agent D-fenfluramine. Panic patients behaved like controls in the CSCR. However, they had a higher level of baseline anxiety and were insensitive to SPS. This profile resembles the reported effect of the non-selective 5-HT receptor blocker metergoline in healthy volunteers. Therefore, panic patients seem to process unconditioned fear abnormally, which may be due to lack of 5-HT inhibition in brain structures commanding flight from proximal danger stimuli.

Effects of tryptophan depletion on anxiety induced by simulated public speaking

Several lines of evidence point to the participation of serotonin (5HT) in anxiety. Its specific role, however, remains obscure. The objective of the present study was to evaluate the effect of reducing 5HT-neurotransmission through an acute tryptophan depletion on anxiety induced by a simulated public speaking (SPS) test. Two groups of 14-15 subjects were submitted to a 24-h diet with a low or normal content of tryptophan and received an amino acid mixture without (TRY-) or with (TRY+) tryptophan under double-blind conditions. Five hours later they were submitted to the SPS test. The state-trait anxiety inventory (STAI) and the visual analogue mood scale (VAMS) were used to measure subjective anxiety. Both scales showed that SPS induced a significant increase in anxiety. Although no overall difference between groups was found, there was a trend (P = 0.078) to an interaction of group x gender x phases of the SPS, and a separate analysis of each gender showed an increase in anxiety measured by the STAI in females of the TRY- group. The results for the female TRY- group also suggested a greater arousing effect of the SPS test. In conclusion, the tryptophan depletion procedure employed in the present study did not induce a significant general change in subjective anxiety, but tended to induce anxiety in females. This suggests a greater sensitivity of the 5HT system to the effects of the procedure in this gender.

Effects of tryptophan depletion on anxiety induced by simulated public speaking.

Several lines of evidence point to the participation of serotonin (5HT) in anxiety. Its specific role, however, remains obscure. The objective of the present study was to evaluate the effect of reducing 5HT-neurotransmission through an acute tryptophan depletion on anxiety induced by a simulated public speaking (SPS) test. Two groups of 14-15 subjects were submitted to a 24-h diet with a low or normal content of tryptophan and received an amino acid mixture without (TRY-) or with (TRY+) tryptophan under double-blind conditions. Five hours later they were submitted to the SPS test. The state-trait anxiety inventory (STAI) and the visual analogue mood scale (VAMS) were used to measure subjective anxiety. Both scales showed that SPS induced a significant increase in anxiety. Although no overall difference between groups was found, there was a trend (P = 0.078) to an interaction of group x gender x phases of the SPS, and a separate analysis of each gender showed an increase in anxiety measured by the STAI in females of the TRY- group. The results for the female TRY- group also suggested a greater arousing effect of the SPS test. In conclusion, the tryptophan depletion procedure employed in the present study did not induce a significant general change in subjective anxiety, but tended to induce anxiety in females. This suggests a greater sensitivity of the 5HT system to the effects of the procedure in this gender.

Comparison of buspirone with diazepam and fluvoxamine on aversive classical conditioning in humans.

The effects of buspirone, fluvoxamine and diazepam were investigated, using healthy volunteers, in an aversive conditioning paradigm, a putative model for conditioned anxiety. The main prediction was that buspirone, an anxiolytic agent which reduces activity in serotonin (5-hydroxytryptophan, 5-HT) neurones, would attenuate aversively conditioned skin conductance responses. Skin conductance responses were recorded to 10 neutral tones (habituation phase). Tone 11 was immediately followed by a 1-s 90-dB aversive white noise (unconditioned stimulus). The conditioning trial reinstated responding to a second presentation of the tones (extinction phase). Skin conductance response amplitude, inter-response level and spontaneous fluctuations were recorded. There were five treatment groups comprising five men and five women. One control group took placebo, another control group received nothing; there was no effect of placebo on any measure. Diazepam (2 mg, p.o.), a positive comparator, markedly reduced the amplitude of skin conductance responses at all phases of the experiment, but only in women. Buspirone (5 mg, p.o.) had the predicted effect of accelerating extinction but also of unexpectedly accelerated habituation of skin conductance responses. There was a trend to reduce spontaneous fluctuations and no effect on skin conductance level. The effects of buspirone were thus specific to responses to stimuli. Fluvoxamine (25 mg, p.o.) had similar effects to buspirone and diazepam in women. An action common to buspirone, fluvoxamine and diazepam, which may account for their shared effect on conditioned autonomic responses, is the suppression of neural activity in the dorsal raphe nucleus. It is argued that enhanced habituation must involve a different mechanism, such as enhanced 5-HT1A function in the terminal fields of the median raphe nucleus.

Molecular characterization and crystallization of Diocleinae lectins.

Molecular characterization of seven Diocleinae lectins was assessed by sequence analysis, determination of molecular masses by mass spectrometry, and analytical ultracentrifugation equilibrium sedimentation. The lectins show distinct pH-dependent dimer-tetramer equilibria, which we hypothesize are due to small primary structure differences at key positions. Lectins from Dioclea guianensis, Dioclea virgata, and Cratylia floribunda seeds have been crystallized and preliminary X-ray diffraction analyses are reported.

Estudo comparativo duplo-cego, randomizado, cruzado, controlado com placebo, da eficácia de nifedipina retard em pacientes refratários a terapêutica basal anti-hipertensiva / Comparative double-blind, randomized crossover study controlled with placebo, of the efficacy of nifedipine retard in patients refractory to basic antihypertensive therapy

Foi efetuado um estudo cruzado comparativo duplo-cego, randomizado, controlado com placebo, para avaliar a eficacia da nifedipina retard quando adicionada a terapeutica basal anti-hipertensiva que nao tenha conseguido baixar os niveis da pressao sanguinea diastolica ate valores normais.Trinta e seis pacientes de ambulatorio com hipertensao leve e moderada receberam nifedipina ou placebo durante 4 semanas apos um periodo de "washout" de 4 semanas. Este procedimento foi seguido por uma semana de placebo e 4 semanas de nifedipina ou placebo. Os pacientes foram avaliados semanalmente. Nifedipina retard foi administrada na dose de 20 mg, 2 vezes ao dia. O placebo foi administrado em regime identico. Em ambos os grupos, a nifedipina provocou uma reducao estatisticamente significativa (p < 0.01) nas pressoes sistolica e diastolica. Nao foram registradas alteracoes significantes na frequencia cardiaca com nifedipina nem alteracoes significantes da pressao sanguinea ou frequencia cardiaca quando se associou placebo a terapeutica basal. A tolerancia foi boa, porem houve casos de discreta cefaleia,edema maleolar e rubor, em alguns pacientes