Ventilatory, metabolic, and thermal responses to hypercapnia in female rats: effects of estrous cycle, ovariectomy, and hormonal replacement

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of a dexmedetomidine constant rate infusion and atropine on changes in global perfusion variables induced by hemorrhage followed by volume replacement in isoflurane-anesthetized dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of different periods of estrogen replacement onset in the tibia of ovariectomized rats

Background and aims Estrogen deficiency results in increased bone turnover and can lead to osteoporosis. Hormone replacement therapy (HRT) seems to be the most effective means of reducing bone loss and fractures. However, the effects of the period of HRT onset on bone tissue require further elucidation. This study aimed to evaluate the effects of different periods of HRT onset on the trabecular bone of ovariectomized rats.Methods Seventy-five ovariectomized Wistar rats were divided into five groups according to the onset of treatment. Each group was subdivided into experimental (E; n = 10) and control (C; n = 5), according to treatment with 17-beta-estradiol or vehicle alone (soybean oil), respectively, administered subcutaneously. The first group received treatment immediately post-surgery, while treatment in the remaining groups was initiated 1, 2, 3 and 4 weeks post-surgery. Euthanasia occurred at 9 weeks post-surgery. The left tibias were removed and prepared for histomorphometric analyses. The histomorphometric results were statistically analyzed by the Student's t test (p < 0.05).Results The percentage of trabecular bone was significantly greater in the first (p = 0.002) and second (p = 0.039) experimental subgroups compared with the control for the same period. In the experimental subgroups, the percentage of trabecular bone decreased according to the delay in HRT onset and was statistically significant (t = 3.367; p = 0.0023).Conclusion These findings indicate an increase in trabecular bone loss in tibia at 9 weeks post-ovariectomy. The period of HRT/E onset is important for preventing bone loss; however, despite its preventive effects, HRT/E does not restore lost bone.

Ingestive behavior of dairy goats fed increasing levels of sugarcane in replacement of corn silage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Congruent spatial and temporal foraging by a dominant ant (Hym., Formicidae) and its replacement in an assemblage in a large urban structure in southeastern Brazil

At fixed bail stations in a large institutional setting in Brazil, the temporal and spatial pattern of usage of the dominant species of ant was studied. The ant Crematogaster cf. magnifica, was found in 91% of sampling points. These studies were conducted using the same points as a previous study of tile then dominant ant. Monomorium pharaonis, which was found to have declined from 93% to 3% spatial point occupation. The frequency of point usage during this study was significantly different from the Poisson distribution for both species, indicating non-random use of space. Crematogaster cf. magnifica was significantly more spatially exclusive than had been documented for M. pharaonis, and the probability of points originally occupied by M. pharaonis later becoming occupied by C. cf. magnifica was in excess of 90%. Temporal bait exploitation patterns of the two species did not differ. These data demonstrate that structural ant communities can change over time without human intervention, although short- term stability is characteristic of the urban dominant ants in subtropical Brazil.

Effects of castration and of testosterone replacement on alpha(1)-adrenoceptor subtypes in the rat vas deferens

The contractions of the rat vas deferens in response to noradrenaline are mediated through alpha(1A)-adrenoceptors. We observed participation of alpha(1B)-adrenoceptors in these contractions after castration. We now investigated the time course of this plasticity and the effects of testosterone by determining the actions of competitive antagonists on noradrenaline-induced contractions after 7, 14, 21 and 30 days of castration. BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride) antagonised noradrenaline-induced contractions in control and castrated rats with low pA(2) values (approximately = 6.8). In control vas deferens, WB 4101 (2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride) had a slope in the Schild plot no different from 1.0, while slopes lower than 1.0 (approximately 0.6) were observed for vas deferens from castrated rats. Chloroethylclonidine was ineffective in the control vas while it inhibited noradrenaline-induced contractions in vasa from castrated rats and converted the complex antagonism by WB 4101 into simple competitive antagonism. Treatment of castrated rats with testosterone prevented the effects of castration. The results suggest that alpha(1B)-adrenoceptors are detectable in vas deferens from at least the 7th through the 30th day after castration and that testosterone prevents this plasticity.

Seal, replacement or monitoring amalgam restorations with occlusal marginal defects? Results of a 10-year clinical trial

The aim of this prospective and blind clinical trial was to assess the effectiveness of sealing localized marginal defects of amalgam restoration that were initially scheduled to be replaced. A cohort of twenty six patients with 60 amalgam restorations (n=44Class I and n=16Class II), that presented marginal defects deviating from ideal (Bravo) according to USPHS criteria, were assigned to either sealing or replacement groups: A: sealing n=20, Replacement n=20, and no treatment (n=20). Two blind examiners evaluated the restorations at baseline (K=0.74) and after ten years (K=0.84) according with USPHS criteria, in four parameters: marginal adaptation (MA), secondary caries (SC), marginal staining (MS) and teeth sensitivity (TS). Multiple comparison of restorations degradation/upgrade was analyzed by Friedman test and the comparisons within groups were performed by Wilcoxon test. After 10 years, 44 restorations were assessed (73.3%), Group A: n=14 and Group B: n=16; and Group C: n=14 sealing and replacement amalgam restorations presented similar level of quality in MA (p=0.76), SC (p=0.25) and TS (p=0.52), while in MS (p=0.007) presented better performance in replacement group after 10-years. Most of the occlusal amalgam restorations with marginal gaps showed similar long term outcomes than the restorations were sealed, replaced, or not treated over a 10-year period. Most of the restorations of the three groups were clinically acceptable, under the studied parameters. All restorations had the tendency to present downgrade/deterioration over time.

Evidence for temporal population replacement and the signature of ecological adaptation in a major Neotropical malaria vector in Amazonian Peru

The major Neotropical malaria vector, Anopheles darlingi, was reintroduced into the Iquitos, Loreto, Peru area during the early 1990s, where it displaced other anophelines and caused a major malaria epidemic. Since then, case numbers in Loreto have fluctuated, but annual increases have been reported since 2012. The population genetic structure of An. darlingi sampled before and after the introduction of long-lasting insecticidal nets (LLINs) was investigated to test the hypothesis of temporal population change (2006 vs. 2012). Current samples of An. darlingi were used to test the hypothesis of ecological adaptation to human modified (highway) compared with wild (riverine) habitat, linked to forest cover. In total, 693 An. darlingi from nine localities in Loreto, Peru area were genotyped using 13 microsatellite loci. To test the hypothesis of habitat differentiation in An. darlingi biting time patterns, HBR and EIR, four collections of An. darlingi from five localities (two riverine and three highway) were analysed. Analyses of microsatellite loci from seven (2006) and nine settlements (2012-2014) in the Iquitos area detected two distinctive populations with little overlap, although it is unclear whether this population replacement event is associated with LLIN distribution or climate. Within the 2012-2014 population two admixed subpopulations, A and B, were differentiated by habitat, with B significantly overrepresented in highway, and both in near-equal proportions in riverine. Both subpopulations had a signature of expansion and there was moderate genetic differentiation between them. Habitat and forest cover level had significant effects on HBR, such that Plasmodium transmission risk, as measured by EIR, in peridomestic riverine settlements was threefold higher than in peridomestic highway settlements. HBR was directly associated with available host biomass rather than forest cover. A population replacement event occurred between 2006 and 2012-2014, concurrently with LLIN distribution and a moderate El Niño event, and prior to an increase in malaria incidence. The likely drivers of this replacement cannot be determined with current data. The present-day An. darlingi population is composed of two highly admixed subpopulations, which appear to be in an early stage of differentiation, triggered by anthropogenic alterations to local habitat.

The mechanism of 234U 238U activity ratio enhancement in karstic limestone groundwater

Experimental etch/leach of Carboniferous Limestone gravels on a laboratory time-scale has demonstrated that 234U 238U activity ratios (AR's) greater than the radiochemical equilibrium value may be generated on short time-scales. The molar U/Ca and Mg/Ca ratios show that both U and Mg are leached preferentially relative to Ca whereas the molar U/Mg ratio is only slightly greater than that of the rock matrix. The generation of enhanced AR's is attributed to a two-stage process in which the limestone surface is dissolved by zero-order etch and silicate minerals so released are subjected to first-order chemical leach of U and Mg. The implications of these results for the production of enhanced AR's in Carboniferous Limestone groundwater are discussed. It is suggested that chemical leaching or exchange of U between groundwater and its particulate load or at the aquifer fluid-solid interface is an important mechanism controlling AR changes as groundwater migrates beyond a redox boundary. AR's for dissolved U in groundwater are more probably related to chemical equilibria than to groundwater age. © 1993.

Tailoring the structure, composition, optical properties and catalytic activity of Ag-Au nanoparticles by the galvanic replacement reaction

This Letter reports on the synthesis of Ag-Au nanoparticles (NPs) with controlled structures and compositions via a galvanic replacement reaction between Ag NPs and AuCl4(aq)- followed by the investigation of their optical and catalytic properties. Our results showed the formation of porous walls, hollow interiors and increased Au content in the Ag-Au NPs as the volume of AuCl4(aq)- employed in the reaction was increased. These variations led to a red shift and broadening of the SPR peaks and an increase of up to 10.9-folds in the catalytic activity towards the reduction of 4-nitrophenol relative to Ag NPs. (C) 2012 Elsevier B.V. All rights reserved.

Replacement of fentanyl infusion by enteral methadone decreases the weaning time from mechanical ventilation: a randomized controlled trial

Introduction: Patients undergoing mechanical ventilation (MV) are frequently administered prolonged and/or high doses of opioids which when removed can cause a withdrawal syndrome and difficulty in weaning from MV. We tested the hypothesis that the introduction of enteral methadone during weaning from sedation and analgesia in critically ill adult patients on MV would decrease the weaning time from MV. Methods: A double-blind randomized controlled trial was conducted in the adult intensive care units (ICUs) of four general hospitals in Brazil. The 75 patients, who met the criteria for weaning from MV and had been using fentanyl for more than five consecutive days, were randomized to the methadone (MG) or control group (CG). Within the first 24 hours after study enrollment, both groups received 80% of the original dose of fentanyl, the MG received enteral methadone and the CG received an enteral placebo. After the first 24 hours, the MG received an intravenous (IV) saline solution (placebo), while the CG received IV fentanyl. For both groups, the IV solution was reduced by 20% every 24 hours. The groups were compared by evaluating the MV weaning time and the duration of MV, as well as the ICU stay and the hospital stay. Results: Of the 75 patients randomized, seven were excluded and 68 were analyzed: 37 from the MG and 31 from the CG. There was a higher probability of early extubation in the MG, but the difference was not significant (hazard ratio: 1.52 (95% confidence interval (CI) 0.87 to 2.64; P = 0.11). The probability of successful weaning by the fifth day was significantly higher in the MG (hazard ratio: 2.64 (95% CI: 1.22 to 5.69; P < 0.02). Among the 54 patients who were successfully weaned (29 from the MG and 25 from the CG), the MV weaning time was significantly lower in the MG (hazard ratio: 2.06; 95% CI 1.17 to 3.63; P < 0.004). Conclusions: The introduction of enteral methadone during weaning from sedation and analgesia in mechanically ventilated patients resulted in a decrease in the weaning time from MV.

Central leptin replacement enhances chemorespiratory responses in leptin-deficient mice independent of changes in body weight

Previous studies showed that leptin-deficient (ob/ob) mice develop obesity and impaired ventilatory responses to CO2 . In this study, we examined if leptin replacement improves chemorespiratory responses to hypercapnia (7 % CO2) in ob/ob mice and if these effects were due to changes in body weight or to the direct effects of leptin in the central nervous system (CNS). was measured via plethysmography in obese leptin-deficient- (ob/ob) and wild-type- (WT) mice before and after leptin (10 mu g/2 mu l day) or vehicle (phosphate buffer solution) were microinjected into the fourth ventricle for four consecutive days. Although baseline was similar between groups, obese ob/ob mice exhibited attenuated compared to WT mice (134 +/- 9 versus 196 +/- 10 ml min(-1)). Fourth ventricle leptin treatment in obese ob/ob mice significantly improved (from 131 +/- 15 to 197 +/- 10 ml min(-1)) by increasing tidal volume (from 0.38 +/- 0.03 to 0.55 +/- 0.02 ml, vehicle and leptin, respectively). Subcutaneous leptin administration at the same dose administered centrally did not change in ob/ob mice. Central leptin treatment in WT had no effect on . Since the fourth ventricle leptin treatment decreased body weight in ob/ob mice, we also examined in lean pair-weighted ob/ob mice and found it to be impaired compared to WT mice. Thus, leptin deficiency, rather than obesity, is the main cause of impaired in ob/ob mice and leptin appears to play an important role in regulating chemorespiratory response by its direct actions on the CNS.

Rice oil as a soybean oil replacement in weanling pig diets

The motivation for including oils in the diets of weanling pigs is to increase dietary energy density to meet the pigs' energy requirements. The purpose of this study was to determine the digestible and metabolizable energy values of semi-refined rice oil (RO) and refined soybean oil (SO) for weanling pigs (Experiment 1), as well as to evaluate how replacing SO with RO in weanling pig diets affects performance, intestinal histology, organ morphometry and the occurrence of diarrhea (Experiment 2). In Experiment 1,21 barrows, averaging 19.63 +/- 0.37 kg body weight (BW), were used in a randomized complete block design experiment, with seven replications per treatment and one pig per experimental unit (metabolism cage). The treatments consisted of a reference diet and two test diets. The test diets were obtained by using 90% of the reference diet and 10% of RO or SO. The experimental period consisted of a 7 days adaptation period, followed by a 5 days collection period of feces and urine. The values of the apparent digestible energy, apparent metabolizable energy and N-corrected apparent metabolizable energy of the oils were, respectively, 26.24, 25.78 and 26.01 MJ kg(-1) for RO and 31.74, 31.35 and 31.51 MJ kg(-1) for SO. In Experiment 2, 120 weaned pigs, castrated males and females, averaging 6.74 +/- 0.42 kg BW, were used in a randomized complete block design experiment, with eight replications per treatment and three pigs per experimental unit (pen) to evaluate the effects of five replacement levels of SO with RO in isonutritive weanling pig diets. The treatments were as follows: 4:0 basal diet with 4% of SO; 3:1 basal diet with 3% of SO and 1% of RO; 2:2 basal diet with 2% of SO and 2% of RO; 1:3 basal diet with 1% of SO and 3% of RO; and 0:4 basal diet with 4% of RO. No effects of the replacement levels were observed in the weanling pigs' performance, organ morphometry or in their occurrence of diarrhea. However, a quadratic effect on the villus width and a cubic effect on the villus height:crypt depth ratio were observed in the duodenum. Therefore, if the determined values of energy are used in the feed formulation, refined soybean oil can be replaced with semi-refined rice oil in weanling pig diets without affecting their growth performance. (C) 2011 Elsevier B.V. All rights reserved.

Toward the optimal dose metric in continuous renal replacement therapy

Purpose: There is no consensus on the optimal method to measure delivered dialysis dose in patients with acute kidney injury (AKI). The use of direct dialysate-side quantification of dose in preference to the use of formal blood-based urea kinetic modeling and simplified blood urea nitrogen (BUN) methods has been recommended for dose assessment in critically-ill patients with AKI. We evaluate six different blood-side and dialysate-side methods for dose quantification. Methods: We examined data from 52 critically-ill patients with AKI requiring dialysis. All patients were treated with pre-dilution CWHDF and regional citrate anticoagulation. Delivered dose was calculated using blood-side and dialysis-side kinetics. Filter function was assessed during the entire course of therapy by calculating BUN to dialysis fluid urea nitrogen (FUN) ratios q/12 hours. Results: Median daily treatment time was 1,413 min (1,260-1,440). The median observed effluent volume per treatment was 2,355 mL/h (2,060-2,863) (p<0.001). Urea mass removal rate was 13.0 +/- 7.6 mg/min. Both EKR (r(2)=0.250; p<0.001) and K-D (r(2)=0.409; p<0.001) showed a good correlation with actual solute removal. EKR and K-D presented a decline in their values that was related to the decrease in filter function assessed by the FUN/BUN ratio. Conclusions: Effluent rate (ml/kg/h) can only empirically provide an estimated of dose in CRRT. For clinical practice, we recommend that the delivered dose should be measured and expressed as K-D. EKR also constitutes a good method for dose comparisons over time and across modalities.

Retrospective Clinical Study of 988 Dual Acid-Etched Implants Placed in Grafted and Native Bone for Single-Tooth Replacement

Purpose: To evaluate the influence of sex, implant characteristics, and bone grafting on the survival rate of dual acid-etched (DAE) implants. Materials and Methods: Patients treated with internal-hex DAE implants for single-tooth replacement in a military dental clinic between January 2005 and December 2010 were included in this study. Clinical data related to implant characteristics, implant location, presence of grafted bone, and implant failures were collected. The primary outcome was implant loss. The survival rate was analyzed using the Kaplan-Meier method. Cox regression modeling was used to determine which factors would predict implant failure. Results: DAE implants were evaluated in a total of 988 patients (80.3% men). Twenty-four (2.4%) implants failed, most were cylindric (54.2%) with regular platforms (70.8%) and were 10 mm long (58.3%). The failure rate was 2.4% for the anterior maxilla, 3.3% for the posterior maxilla, 1.6% for the anterior mandible, and 2.0% for posterior mandible. The cumulative survival rate was 97.6%. The failure rate was 8.8% in implants placed after sinus augmentation, 7.3% in bone block-grafted areas, and 1.6% in native bone. Based on multivariable analysis (Cox regression), sinus augmentation and bone block grafting had a statistically significant effect on implant failure; the hazard ratios were 5.5 and 4.6, respectively. Conclusion: The results revealed that DAE implants had high survival rates, and no influence of sex, location, shape, diameter, or length on failure rates could be observed. However, a significant association was observed between failure and presence of bone graft in the implant area. Int J Oral Maxillofac Implants 2012;27:1243-1248