Influence of light intensity and salt-treatment on mode of photosynthesis and enzymes of the antioxidative response system of Mesembryanthemum crystallinum

The metabolic switch From C-3-photosynthesis to crassulacean acid metabolism (CAM),and the antioxidative response of Mesembryanthemum crystallinum L. plants cultured under severe salt stress and high light intensities, and a combination of booth stress conditions, were studied. High light conditions led to a more rapid CAM induction than salinity. The induction time was still shortened when both stress factors were combined. A main pattern observed in CAM plants was a decrease in mitochondrial Mn-superoxide dismutase (SOD) activity during the day. The activities of the chloroplastic Fe-SOD and cytosolic CuZn-SOD were increased due to salt treatment after a lag phase, while catalase activity was decreased. Combination of salt and light stress did not lead to a higher SOD activity as found after application of one stress factor alone, indicating that there is a threshold level of the oxidative stress response. The fact that salt-stressed plants grown under high light conditions showed permanent photoinhibition and lost the ability for nocturnal malate storage after 9 d of treatment indicate serious malfunction of metabolism, leading to accelerated senescence. Comparison of CuZn-SOD activity with CuZn-SOD protein amount, which was determined immunologically, indicates that the activity of the enzyme is at least partially post-translationally regulated.

Biochemical changes during the induction of mineral stress in plants of bell pepper cultivated in fertigation system

The greenhouse production associated with the fertigation management, have established in Brazil as economical alternative for several horticultural species. With this strategy this study had as aim to evaluate possible impacts in the metabolism of plants of bell pepper (Capsicum annuum L.; cv Elisa) in response to the increase of mineral concentration in the soil. During the experiments, the some nutrient concentrations were altered, to obtain high values of electric conductivity (EC) in the soil solution. The EC values commonly observed in the traditional fertigation system were adopted, as control. It was also verified the possibility of reduction of the mineral stress impact by the application of organic matter in the soil. Parameters of the antioxidative response system, as the superoxide dismutase (SOD) and catalase enzyme activities besides the proline content were evaluated to measure the extension of the saline stress and their effects on the plants. The increase of EC of the soil induced to the increase of the proline concentration and the SOD activity. Unexpectedly, it was verified that the saline stress inhibited the activity of the enzyme catalase. It was also concluded that the monitoring of EC of the soil is an indispensable tool to reach success in the fertigation system and that the study of the activity of the enzymes of the antioxidative response system, and the proline contents can be assumed as indicators in of the levels of stress in bell pepper plants (Capsicum annuum L.; cv Elisa).

Conductive hearing loss in children with bronchopulmonary dysplasia: A longitudinal follow-up study in children aged between 6 and 24 months

Aims: To determine the occurrence of isolated and recurrent episodes of conductive hearing loss (CHL) during the first two years of life in very low birth weight (VLBW) infants with and without bronchopulmonary dysplasia (BPD).Study design, subjects and outcome measures: In a longitudinal clinical study. 187 children were evaluated at 6, 9, 12,15 18 and 24 months of age by visual reinforcement audiometry, tympanometry and auditory brain response system.Results: of the children with BPD, 54.5% presented with episodes of CHL, as opposed to 34.7% of the children without BPD. This difference was found to be statistically significant. The recurrent or persistent episodes were more frequent among children with BPD (25.7%) than among those without BPD (8.3%). The independent variables that contributed to this finding were small for gestational age and a 5 min Apgar score.Conclusions: Recurrent CHL episodes are more frequent among VLBW infants with BPD than among VLBW infants without BPD. (C) 2010 Elsevier B.V. All rights reserved.

Effects of hydric deficiency on gas exchange parameters and metabolism of Eucalyptus grandis clones

The metabolic effects caused by hydric deficiency (HD) on Eucalyptus grandis clones were assessed by an experiment where plants were cultivated in four blocks. The first was the control block, normally irrigated, whereas the other three blocks were submitted to cycles of hydric deficiency. Analysis of photosynthetic efficiency, enzymatic activity of antioxidant response system, level of pigments and L-proline concentration were performed to evaluate the HD effects. Results showed that HD altered some parameters related to photosynthetic activity, pigments accumulation, proline and enzymatic activity. Clone 433 of E. grandis presented higher response ability to HD.

Produção de óleo essencial associado à deficiência hídrica em plantas Ocimum basilicum L. cv. genovese

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Agua de reuso e seu efeito sobre parâmetros fisiológicos em manjericão (Ocimum basilicum L.)

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Human pulp response after an adhesive system application in deep cavities

Objectives: To evaluate the pulpo-dentin complex response to a dentin adhesive application in deep cavities performed in human teeth.Methods: Deep class V cavities were prepared on the buccal surface of 46 premolars. The remaining dentin of the axial wall received 10% phosphoric acid and dentin adhesive (group DA), or was protected before the acid and dentin adhesive application with calcium hydroxide cement (group CH). Half of the teeth, which received the acid application directly over the axial wall, were contaminated prior to the procedures with dental plaque collected from the patient's own teeth (group DAC). The plaque was placed on the dentin for 5 min and then the cavity was washed. All teeth were restored with a light-cured composite resin. The teeth were extracted after 7, 30 or 60 days and prepared according to normal histologic techniques. Serial sections were stained with WE, Masson's trichrome and Brown & Brenn technique for demonstration of bacteria.Results: the histopathologic evaluation showed that in groups DA and DAC, the inflammatory response was more evident than in group CH. Also, the intensity of the pulp reaction increased as the remaining dentin thickness decreased. There was no statistical difference in the inflammatory response between the groups DA and DAC.Conclusion: Based on the experimental conditions, we concluded that the All Bond 2 adhesive system, when applied on dentin in deep cavities, showed an acceptable biocompatibility. However, the intensity of the pulpo-dentin complex response depends on the remaining dentin thickness. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

Human pulpal response to direct pulp capping with an adhesive system

Purpose: To evaluate clinically and microscopically the human pulp response when directly capped with an adhesive system or calcium hydroxide over short (9-12 days) and long (53-204 days) experimental periods. Materials and Methods: Fifty-one sound human premolars scheduled for orthodontic extraction, had their pulp horns gently exposed with a diamond point. Debris in the pulp wound was washed out with a sterile saline solution. The pulps were then capped with either an adhesive system (Scotchbond Multi-Purpose Plus) or calcium hydroxide. All teeth were subsequently restored with resin-based composite (Z-100) according to the manufacturer's instructions. After the experimental periods, the teeth were extracted and processed for light microscopic examination. Results: Short-term: the pulp tissue capped with SBMP-P exhibited dilated and congested blood vessels associated with a mo;derate inflammatory response and blanching of pulp cell nuclei. Long-term: no evidence of healing and bridge formation was observed. A persistent mild inflammatory pulp response was present. Micro-abscesses were detected in three cases associated with bacterial infiltration. Calcium hydroxide stimulated early pulp repair and dentin bridging which extended into the longest period.

The sympathetic adrenomedullary system, but not the hypothalamic-pituitary-adrenal axis, participates in aorta adaptive response to stress: nitric oxide involvement

Stress induced a decrease in the reactivity of the aorta to noradrenaline (NA), as a consequence of an endothelial nitric oxide (NO) system hyperactivity. The main characteristic of the stress response is activation of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic adrenomedullary (SA) system. The participation of the HPA axis and SA system in the decreased reactivity to NA in the aorta of rats exposed to 4-h immobilization was investigated. Concentration-response relationships for NA were obtained in the aorta, with and without endothelium, isolated from normal and stressed rats, following these procedures: (1) in the absence and presence of L-NAME; (2) after adrenalectomy (ADX) or not, in the absence or presence of L-NAME; (3) ADX rats treated or not with corticosterone; (4) ADX associated with stress; and (5) treated or not with reserpine. The reactivity of aorta without endothelium was unaffected by the procedures. The reactivity of aorta with endothelium was decreased by either stress or ADX. This effect was reversed by both L-NAME and corticosterone. ADX did not potentiate the decrease in the aorta reactivity induced by stress. Reserpine did not change the reactivity of aorta with endothelium from normal rats, but prevented the decrease in reactivity induced by stress. It is concluded that the HPA axis participates in endothelium-dependent modulation of aorta reactivity in normal conditions and that thr SA system participates in hyperactivity of the endothelial NO-system induced by stress, which is responsible for the decreased aorta reactivity to NA. (C) 2000 Elsevier B.V. B.V. All rights reserved.

On the effects of system parameters on the response of a harmonically excited system consisting of weakly coupled nonlinear and linear oscillators

This paper discusses the dynamic behaviour of a nonlinear two degree-of-freedom system consisting of a harmonically excited linear oscillator weakly connected to a nonlinear attachment having linear and cubic restoring forces. The effects of the system parameters on the shape of the frequency-response curve are investigated, in particular those yielding the appearance and disappearance of outer and inner detached resonance curves. In contrast to the case when the linear stiffness of the attachment is zero, it is found that multivaluedness occurs at low frequencies as the resonant peak bends to the right. It is also found that as the coefficient of the linear term increases, the range of parameters yielding detached curves reduces. Compared to the case when the attached system has no linear stiffness term, this range of parameters corresponds to smaller values of the damping and nonlinear coefficients. Approximate analytical expressions for the jump-up and jump-down frequencies of the system under investigation are also derived. (C) 2011 Elsevier Ltd. All rights reserved.

Functional evidence that the central renin-angiotensin system plays a role in the pressor response induced by central injection of carbachol

We investigated the effects of losartan, an AT 1-receptor blocker, and ramipril, a converting enzyme inhibitor, on the pressor response induced by angiotensin II (ANG II) and carbachol (a cholinergic receptor agonist). Male Holtzman rats (250-300 g) with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The injection of losartan (50 nmol/l μl) into the LV blocked the pressor response induced by ANG II (12 ng/l μl) and carbachol (2 nmol/l μl). After injection of ANG II and carbachol into the LV, mean arterial pressure (MAP) increased to 31 ± 1 and 28 ± 2 mmHg, respectively. Previous injection of losartan abolished the increase in MAP induced by ANG II and carbachol into the LV (2 ± 1 and 5 ± 2 mmHg, respectively). The injection of ramipril (12 ng/l μl) prior to carbachol blocked the pressor effect of carbachol to 7 ± 3 mmHg. These results suggest an interaction between central cholinergic pathways and the angiotensinergic system in the regulation of arterial blood pressure.

Response of human pulps capped with a self-etching adhesive system

Objective: The aim of this study was to evaluate the human pulp response following direct pulp capping with a current self-etching bonding agent and calcium hydroxide (CH). Methods: Thirty-three sound human premolars had their pulp tissue mechanically exposed. Sterile distilled water was used to control the hemorrhage and exudation from the pulp exposure site. The pulps were capped with Clearfil Liner Bond 2 (CLB-2) or CH and the cavities were filled with a resin composite (Z-100) according to the manufacturer's instructions. After 5, 30 and 120-300 days, the teeth were extracted and processed for microscopic examination. Results: At short-term, CLB-2 elicited a mild to moderate inflammatory pulp response with dilated and congested blood vessels adjacent to pulp exposure site. With time, macrophages and giant cells engulfing globules and particulates of resinous material displaced into the pulp space were observed. This chronic inflammatory pulp response triggered by fragments of bonding agent displaced into the pulp space did not allow pulp repair interfering with the dentin bridging. On the other hand, pulps capped with CH exhibited an initial organization of elongated pulp cells underneath the coagulation necrosis. Pulp repair and complete dentin bridge formation was observed at long-term evaluation. Significance: The present study demonstrated that CH remains the pulp capping agent of choice for mechanically exposed human pulps. CLB-2 did not allow complete connective tissue repair adjacent to the pulp exposure site. Consequently, this bonding agent cannot be recommended for pulp therapy of sound human teeth. © 2001 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.