The Influence of Early Life Interventions on Olfactory Memory Related to Palatable Food, and on Oxidative Stress Parameters and Na+/K+-ATPase Activity in the Hippocampus and Olfactory Bulb of Female Adult Rats

The effects of neonatal handling and the absence of ovarian hormones on the olfactory memory related to a palatable food in adulthood were investigated. Oxidative stress parameters and Na+/K+-ATPase activity in the hippocampus and olfactory bulb of adult pre-puberty ovariectomized female rats handled or not in the neonatal period were also evaluated. Litters were non-handled or handled (10 min/day, days 1-10 after birth). Females from each litter were divided into: OVX (subjected to ovariectomy), sham, and intact. When adults, olfactory memory related to a palatable food (chocolate) was evaluate using the hole-board olfactory task. Additionally, oxidative stress parameters and Na+/K+-ATPase activity were measured in the hippocampus and olfactory bulb. No difference between groups was observed considering olfactory memory evaluation. Neonatal handled rats presented an increase in Na+/K+-ATPase activity in the hippocampus and in the olfactory bulb, compared to non-handled ones. Considering the surgical procedure, there was a decrease in Na+/K+-ATPase and catalase activities in sham and OVX groups, compared to intact animals in the olfactory bulb. We concluded that olfactory memory related to a palatable food in adulthood was not affected by neonatal handling or by pre-puberty surgery, with or without removal of ovaries. The difference observed between groups in catalase and Na+/K+-ATPase activity does not seem to be related to the olfactory memory. Additionally, the increase in Na+/K+-ATPase activity (an enzyme that maintains the neurochemical gradient necessary for neuronal excitability) induced by neonatal handling may be related to neuroplastic changes in the hippocampus and olfactory bulb.     

Acute Portal Hypertension Models in Dogs: Low- and High-Flow Approaches

Effective animal models are needed to evaluate the feasibility of new techniques to assess portal hypertension (PH). Here we developed 2 canine models of acute PH by increasing intrasinusoidal resistance and by increasing the portal vein (PV) flow volume to test the efficacy of a noninvasive technique to evaluate PH. The acute low-flow PH model was based on embolization of liver circulation by using a gelatin sponge material. The acute high-flow PH model was based on increasing the PV flow volume by using an arteriovenous (A-V) shunt from the femoral artery and saline infusion. PV pressures and diameters were assessed before and after inducing PH. Pressure values and diameters were obtained from the inferior vena cava in 3 unmanipulated controls. The low-flow model of PH was repeatable and successfully increased PV pressure by an average of 16.5 mm Hg within 15 min. The high-flow model of PH failed to achieve increased PV pressures. However, saline supplementation of the portal circulation in the high-flow model led to mean increases in PV pressures of 12.8 mm Hg within 20 min. Pulsatility in the PV was decreased in the low-flow model and increased in the high-flow model relative to baseline. No changes in PV diameter were noted in either model. These acute PH models are relatively straightforward to implement and may facilitate the evaluation of new techniques to assess PH.Abbreviations: PH, portal hypertension; PV, portal vein; A-V shunt, arterial-venous shunt; IVC, inferior vena cavaPortal hypertension (PH) marks the silent progression of cirrhotic liver from a preclinical to a clinical phase, when symptoms associated with common complications like ascites, variceal bleeding, and encephalopathy manifest and can be fatal (mortality rates of 20% to 70%).^7,12,31,34 The hepatic venous pressure gradient is used clinically to diagnose PH, but the technique is invasive and is not routinely used for screening potential PH cases.^26,39 Development of a noninvasive technique to identify nascent PH has great clinical value.³⁹ The long-term goal of our project is to develop and evaluate a contrast-enhanced ultrasound imaging-based noninvasive pressure estimation technique^{9,10,17,20,37} as a means to identify PH. Before clinical testing of this approach, we conducted feasibility studies in animal models to confirm the accuracy of this new technique. Here we developed 2 canine acute PH models to test the efficacy of our noninvasive pressure estimation technique to evaluate PH.Current animal PH models include those in mice, rats, pigs, rabbits, and dogs.^{1,5,11,13,21,23,27,33,38,41} Guidelines for selecting a particular animal PH model (or for other hepatic abnormalities) have also been published.³⁰ In view of these guidelines, we selected dogs for our study, because the blood vessels of smaller animals may be difficult to catheterize and because some species, like swine, develop marked pulmonary hypertension during contrast-enhanced ultrasound imaging.³² Moreover, our team has extensive experience with canine experiments, and we have noted no side effects in dogs after the administration of the contrast material for ultrasound imaging.^9,10,17 Furthermore the physiology of dogs closely approximates that of humans.²³Animal models and clinical studies have shown that a pathophysiologic increase in intrahepatic vascular resistance ultimately leads to PH,^12,31 whereas etiologically the origin of PH may be pre-, intra-, or postsinusoidal.⁶ Overall, a modified form of Ohm''s law for fluid flow (∆P = Q × R, where ∆P is the change in pressure, Q is flow, and R is resistance) explains increases in portal vein (PV) pressures,¹ either by an increase in PV flow, an increase in resistance to PV flow, or a combination of these 2 mechanisms. Therefore, we sought to develop 2 acute PH models in dogs, with one resulting from increased resistance to PV flow (a low-flow model of PH) and the other from an increase in the volume of PV flow (a high-flow model of PH).For our acute low-flow model of PH, we increased the intrasinusoidal resistance in the liver parenchyma by injecting a gelatin sponge material (Gelfoam, Ethicon, Somerville, NJ) via the PV. This product has been used previously in dogs²⁸ and does not elicit foreign-body reactions or inflammation.²² We hypothesized that PV pressures would increase and the pulsatility of PV flow would decrease (due to the decrease in flow) after administration of the gelatin material. For the acute high-flow PH model, we used an arteriovenous (A-V) shunt, which was created by connecting the splenic or femoral artery to the PV. We hypothesized that, in this model, both PV pressure and pulsatility would increase (due to the superimposition of arterial flow) after initiating the high-flow conditions in the PV.     

Predictive models for the diagnostic of human visceral leishmaniasis in Brazil

Background and Objectives

In Brazil, as in many other affected countries, a large proportion of visceral leishmaniasis (VL) occurs in remote locations and treatment is often performed on basis of clinical suspicion. This study aimed at developing predictive models to help with the clinical management of VL in patients with suggestive clinical of disease.

Methods

Cases of VL (n = 213) had the diagnosis confirmed by parasitological method, non-cases (n = 119) presented suggestive clinical presentation of VL but a negative parasitological diagnosis and a firm diagnosis of another disease. The original data set was divided into two samples for generation and validation of the prediction models. Prediction models based on clinical signs and symptoms, results of laboratory exams and results of five different serological tests, were developed by means of logistic regression and classification and regression trees (CART). From these models, clinical-laboratory and diagnostic prediction scores were generated. The area under the receiver operator characteristic curve, sensitivity, specificity, and positive predictive value were used to evaluate the models'' performance.

Results

Based on the variables splenomegaly, presence of cough and leukopenia and on the results of five serological tests it was possible to generate six predictive models using logistic regression, showing sensitivity ranging from 90.1 to 99.0% and specificity ranging from 53.0 to 97.2%. Based on the variables splenomegaly, leukopenia, cough, age and weight loss and on the results of five serological tests six predictive models were generated using CART with sensitivity ranging from 90.1 to 97.2% and specificity ranging from 68.4 to 97.4%. The models composed of clinical-laboratory variables and the rk39 rapid test showed the best performance.

Conclusion

The predictive models showed to be a potential useful tool to assist healthcare systems and control programs in their strategical choices, contributing to more efficient and more rational allocation of healthcare resources.     

Evaluation of the Adenanthera pavonina seed proteinase inhibitor (ApTI) as a bioinsecticidal tool with potential for the control of Diatraea saccharalis

Diatraea saccharalis, is a major sugarcane pest, causing damage to the stalks of sugarcane plants. In this study, a trypsin inhibitor (ApTI) was purified from Adenanthera pavonina seeds and was tested for its insect growth regulatory effect. ApTI showed a dose-dependent effect on average larval weight and survival. 0.1% ApTI produced approximately 67% and 50% decreases in weight and survival larval, respectively. The results from dietary utilization experiments with D. saccharalis larvae showed a reduction in the efficiency of conversion of ingested food and digested food, and an increase in approximate digestibility and metabolic cost. The level of trypsin was significantly decreased (ca. 55%) in the midgut of larvae reared on a diet containing 0.05% ApTI and the trypsin activity in ApTI-fed larvae demonstrated sensitivity to ApTI. The action of ApTI on the development of D. saccharalis larvae shows that this protein may have great toxic potential.     

Synthesis and properties of cyclic gomesin and analogues

Gomesin (Gm) was the first antimicrobial peptide (AMP) isolated from the hemocytes of a spider, the Brazilian mygalomorph Acanthoscurria gomesiana. We have been studying the properties of this interesting AMP, which also displays anticancer, antimalarial, anticryptococcal and anti‐Leishmania activities. In the present study, the total syntheses of backbone‐cyclized analogues of Gm (two disulfide bonds), [Cys(Acm)^2,15]‐Gm (one disulfide bond) and [Thr^2,6,11,15,d ‐Pro⁹]‐Gm (no disulfide bonds) were accomplished, and the impact of cyclization on their properties was examined. The consequence of simultaneous deletion of pGlu¹ and Arg¹⁶‐Glu‐Arg¹⁸‐NH₂ on Gm antimicrobial activity and structure was also analyzed. The results obtained showed that the synthetic route that includes peptide backbone cyclization on resin was advantageous and that a combination of 20% DMSO/NMP, EDC/HOBt, 60 °C and conventional heating appears to be particularly suitable for backbone cyclization of bioactive peptides. The biological properties of the Gm analogues clearly revealed that the N‐terminal amino acid pGlu¹ and the amidated C‐terminal tripeptide Arg¹⁶‐Glu‐Arg¹⁸‐NH₂ play a major role in the interaction of Gm with the target membranes. Moreover, backbone cyclization practically did not affect the stability of the peptides in human serum; it also did not affect or enhanced hemolytic activity, but induced selectivity and, in some cases, discrete enhancements of antimicrobial activity and salt tolerance. Because of its high therapeutic index, easy synthesis and lower cost, the [Thr^2,6,11,15,d ‐Pro⁹]‐Gm analogue remains the best active Gm‐derived AMP developed so far; nevertheless, its elevated instability in human serum may limit its therapeutic potential. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Nitric oxide at the CVLM is involved in the attenuation of the reflex bradycardia in renovascular hypertensive rats

Hypertension is associated to an increase in central oxidative stress and an attenuation of the baroreflex control of arterial pressure. The present study evaluated the effect of alterations in the levels of nitric oxide (NO) and superoxide anion in the caudal ventrolateral medulla (CVLM), a key area of the brainstem for the baroreflex control of arterial pressure, in renovascular hypertensive rats (2K1C). Baseline mean arterial pressure (MAP), heart rate (HR), and reflex bradycardia were evaluated 30 days after renal artery occlusion in anesthetized (urethane, 1.2 g/kg, i.p.) 2K1C or normotensive (SHAM) rats. The MAP, HR, and baroreflex control of HR were evaluated before and after CVLM microinjections of the non-selective NOS inhibitor L-NAME (10 nmol), the NO precursor L-ARG (50 nmol), or the antioxidant ascorbic acid, Vit C (10 nmol). In both 2K1C and SHAM animals, CVLM microinjection of L-NAME produced a decrease in MAP, whereas L-ARG induced a significant increase in MAP. However, microinjection of Vit C into the CVLM produced a decrease in MAP and HR only in 2K1C and not in SHAM rats. Cardiovascular effects produced by microinjection of l-ARG into the CVLM were abolished by prior microinjection of L-NAME in the CVLM of 2K1C and SHAM rats. Microinjection of L-NAME into the CVLM increased the sensitivity of reflex bradycardia in 2K1C animals. In contrast, the CVLM microinjection of L-ARG reduced reflex bradycardia only in SHAM rats. Vit C in the CVLM did not change reflex bradycardia in either 2K1C or in SHAM rats. These results suggest that increased oxidative stress in the CVLM during hypertension contributes to the reduced baroreflex sensitivity and to maintain hypertension in the 2K1C model.     

A selection platform for carbon chain elongation using the CoA-dependent pathway to produce linear higher alcohols

Production of green chemicals and fuels using metabolically engineered organisms has been a promising alternative to petroleum-based production. Higher chain alcohols (C4-C8) are of interest because they can be used as chemical feedstock as well as fuels. Recently, the feasibility of n-hexanol synthesis using Escherichia coli has been demonstrated by extending the modified Clostridium CoA-dependent n-butanol synthesis pathway, thereby elongating carbon chain length via reactions in reversed β-oxidation, (or β-reduction). Here, we developed an anaerobic growth selection platform that allows selection or enrichment of enzymes for increased synthesis of C6 and C8 linear alcohols. Using this selection, we were able to improve the carbon flux towards the synthesis of C6 and C8 acyl-CoA intermediates. Replacement of the original enzyme Clostridium acetobutylicum Hbd with Ralstonia eutropha homologue PaaH1 increased production of n-hexanol by 10-fold. Further directed evolution by random mutagenesis of PaaH1 improved n-hexanol and n-octanol production. This anaerobic growth selection platform may be useful for selecting enzymes for production of long-chain alcohols and acids using this CoA-dependent pathway.     

Medical practice opinion

To provide an effective continuum of the relief of severe carcinomatous pain with minimal side reactions, we initiated treatment with piroxicam (60 to 120 mg per day) and doxepin hydrochloride (25 to 225 mg per day). Of 30 patients presenting with severe pain of cancer of various origins, 7 continued to death with piroxicam and doxepin therapy. An additional 17 were successfully treated for 6 to 66 weeks with therapy reported here but, as disease progressed, required supplemental narcotics. The remaining six abandoned the use of piroxicam due to complications of therapy, which ranged from diarrhea to gastric perforation; serious complications were associated with patients'' failure to adhere to a prescribed regimen of sucralfate. Therapy with piroxicam and doxepin proved to be safe and efficacious.     

Endosperm culture: a facile and efficient biotechnological tool to generate passion fruit (Passiflora cincinnata Mast.) triploid plants

Plant Cell, Tissue and Organ Culture (PCTOC) - Triploid plants represent an important resource for the breeding of fruit and ornamental plants. Here, we report a facile and robust system for...