Oral administration of a recombinant modified RBD antigen of SARS-CoV-2 as a possible immunostimulant for the care of COVID-19.

BACKGROUND: Developing effective vaccines against SARS-CoV-2 that consider manufacturing limitations, equitable access, and acceptance is necessary for developing platforms to produce antigens that can be efficiently presented for generating neutralizing antibodies and as a model for new vaccines. RESULTS: This work presents the development of an applicable technology through the oral administration of the SARS-CoV-2 RBD antigen fused with a peptide to improve its antigenic presentation. We focused on the development and production of the recombinant receptor binding domain (RBD) produced in E. coli modified with the addition of amino acids extension designed to improve antigen presentation. The production was carried out in shake flask and bioreactor cultures, obtaining around 200 mg/L of the antigen. The peptide-fused RBD and peptide-free RBD proteins were characterized and compared using SDS-PAGE gel, high-performance chromatography, and circular dichroism. The peptide-fused RBD was formulated in an oil-in-water emulsion for oral mice immunization. The peptide-fused RBD, compared to RBD, induced robust IgG production in mice, capable of recognizing the recombinant RBD in Enzyme-linked immunosorbent assays. In addition, the peptide-fused RBD generated neutralizing antibodies in the sera of the dosed mice. The formulation showed no reactive episodes and no changes in temperature or vomiting. CONCLUSIONS: Our study demonstrated the effectiveness of the designed peptide added to the RBD to improve antigen immunostimulation by oral administration.

Bridging the translational gap: what can synaptopathies tell us about autism?

Multiple molecular pathways and cellular processes have been implicated in the neurobiology of autism and other neurodevelopmental conditions. There is a current focus on synaptic gene conditions, or synaptopathies, which refer to clinical conditions associated with rare genetic variants disrupting genes involved in synaptic biology. Synaptopathies are commonly associated with autism and developmental delay and may be associated with a range of other neuropsychiatric outcomes. Altered synaptic biology is suggested by both preclinical and clinical studies in autism based on evidence of differences in early brain structural development and altered glutamatergic and GABAergic neurotransmission potentially perturbing excitatory and inhibitory balance. This review focusses on the NRXN-NLGN-SHANK pathway, which is implicated in the synaptic assembly, trans-synaptic signalling, and synaptic functioning. We provide an overview of the insights from preclinical molecular studies of the pathway. Concentrating on NRXN1 deletion and SHANK3 mutations, we discuss emerging understanding of cellular processes and electrophysiology from induced pluripotent stem cells (iPSC) models derived from individuals with synaptopathies, neuroimaging and behavioural findings in animal models of Nrxn1 and Shank3 synaptic gene conditions, and key findings regarding autism features, brain and behavioural phenotypes from human clinical studies of synaptopathies. The identification of molecular-based biomarkers from preclinical models aims to advance the development of targeted therapeutic treatments. However, it remains challenging to translate preclinical animal models and iPSC studies to interpret human brain development and autism features. We discuss the existing challenges in preclinical and clinical synaptopathy research, and potential solutions to align methodologies across preclinical and clinical research. Bridging the translational gap between preclinical and clinical studies will be necessary to understand biological mechanisms, to identify targeted therapies, and ultimately to progress towards personalised approaches for complex neurodevelopmental conditions such as autism.

Multiple Interventions to Thoracoabdominal Aortic Aneurysm in a Child With Tuberous Sclerosis.

Thoracoabdominal aortic aneurysms in toddlers are extremely rare. However, we experienced an extent III thoracoabdominal aortic aneurysm in a boy with tuberous sclerosis who underwent 3 open repairs and 1 endovascular aortic repair between the ages of 4 years and 18 years. This case highlights the potential for severe recurrent vascular aneurysms in the thoracic and abdominal aorta as a complication of tuberous sclerosis in children. Although aortic aneurysms in children are rare, it is vital to recognize these cases to prevent death due to rupture.

Safety of Transcarotid Revascularization in Patients with a Contraindication to Dual Antiplatelets.

OBJECTIVE: Current carotid artery stenting practice guidelines recommend dual antiplatelets to reduce major adverse cardiovascular events during and after transcarotid revascularization (TCAR). However, some patients are poor candidates for this regimen, due to preexisting need for anticoagulation, allergies, and/or risk of major bleeding. Therefore, this investigation was performed to review outcomes associated with patients undergoing TCAR while on alternative medication regimens to determine safety and efficacy. METHODS: A retrospective review was performed of a combined database created by the combination of institutional carotid revascularization archives maintained at 2 high-volume TCAR health systems. Patients taking dual antiplatelets were compared to those on nontraditional medications with respect to demographics and perioperative and long-term outcomes. RESULTS: Between our 2 member institutions, 729 TCAR procedures, consisting of 549 patients on dual antiplatelets and 180 on alternative treatments, qualified for study inclusion and analyzed. The cohort not taking dual antiplatelets presented with a heavier comorbidity burden by Charlson Comorbidity Index (5.3 ± 2.2 vs 6.1 ± 2.2, P < .01). Additionally, these patients underwent higher risk revascularization procedures, as they had a higher proportion of symptomatic lesions (34.6% vs 43.0%, P = .03). Despite these deviations in baseline characteristics, similar outcomes between groups were observed in the 30-day perioperative period with respect to stroke (2.2% vs 2.8%, P = .58), death (1.3% vs 1.1%, P > .99), and myocardial infarction (.4% vs 0%, P > .99). Similarly, rates of reintervention (1.6% vs 1.1%, P > .99), hematoma formation (2.4% vs 2.2%, P > .99), and stent thrombosis (.5% vs .6%, P > .99) were consistent, regardless of antiplatelet status. At follow-up of 25.4 and 29.1 months, respectively, for the dual antiplatelet and alternative treatment cohorts, no deviations with respect to reintervention, stroke, myocardial infarction, or stent thrombosis were noted. However, there was an increased risk of death (5.4% vs 13.5%, P = .02) in the alternative regimen group. CONCLUSION: In this small series of TCARs, patients not maintained on dual antiplatelets did not experience more perioperative adverse events after TCAR. However, more studies, in larger series, are required to verify and validate these findings.

Environmental enrichment attenuates conditioned taste aversion through the restoration of BDNF levels in the insular cortex.

It has been shown that exposure to an enriched environment (EE) can modulate the physiological impact of aversive stimuli in animals, promoting adaptive attitudes, as well as the development of resilience to stressful situations. These changes are known to be related to increased levels of some trophic factors, such as brain-derived neurotrophic factor (BDNF), which has been considered a regulatory protein for synaptic plasticity in the adult brain. Our previous studies have demonstrated that in the insular cortex (IC), a brain region of the temporal lobe implicated in the acquisition, consolidation, and retention of conditioned taste aversion (CTA) task, BDNF can reverse the CTA memory deficit caused by a protein synthesis inhibitor. Likewise, our research group have also shown that BDNF is required for the maintenance of CTA long-term memory. Here we evaluate the effects of the exposure to an enriched environment on the CTA memory strength, using a weak and strong version of this paradigm. The exposure to an EE for 21 days was able to attenuate the strong-CTA response through the restoration of BDNF levels in the IC of adult rats. These results provide evidence that environmental enrichment is capable of reducing the strength of an aversive memory trace, restoring the BDNF levels in a neocortical region of the adult brain.

Institutional Experiences with Transfemoral Compared to Transcarotid Stenting.

BACKGROUND: Transcarotid artery revascularization (TCAR) is a new surgical technique that is gaining popularity over the transfemoral method (TF-CAS) as the preferred strategy to deliver a carotid stent. This investigation was performed to evaluate the real-world perioperative and long-term outcomes of both techniques at the health system level. METHODS: A retrospective review of prospectively maintained carotid revascularization databases were performed at 2 high-volume TCAR centers in the United States to extract consecutive TF-CAS and TCAR procedures. The characteristics and outcomes associated with these 2 modalities were compared at the preoperative and perioperative points by univariate methods. The Kaplan-Meier methodology was utilized to calculate the long-term stroke and death trends. RESULTS: From 2008-2021, 1,058 carotid stents were implanted at our institutions, consisting of 750 TCARs and 308 TF-CAS procedures. Patients undergoing TF-CAS were older (68.2 ± 0.6 vs. 73.1 ± 0.3 years, P < 0.01) and unhealthier by Charlson Comorbidity Index (4.9 ± 0.1 vs. 5.5 ± 0.1, P < 0.01). Additionally, TF-CAS patients had more high-risk anatomic characteristics, such as restenosis after previous carotid surgery (27.0% vs. 9.5%, P < 0.01), previous ipsilateral neck surgery (38.8% vs. 11.5%, P < 0.01), irradiated ipsilateral field (20.4% vs. 4.5%, P < 0.01), and a contralateral carotid occlusion (10.4% vs. 4.6%, P < 0.01). The incidence of symptomatic lesions was the same (40.1% vs. 36.9%, P = 0.35). Within the operating room, TCAR outperformed TF-CAS with respect to operative time (83.2 ± 2.6 vs. 64.3 ± 0.9 min, P < 0.01), radiation exposure (769.9 ± 144.3 vs. 232.7 ± 19.1 mGys, P < 0.01), fluoroscopic time (17.8 ± 1.1 vs. 4.5 ± 0.1 min, P < 0.01), and contrast volume (75.2 ± 2.4 vs. 22.6 ± 0.4 mLs, P < 0.01). In the 30-day perioperative period, ipsilateral stroke (2.8% vs. 2.3%, P = 0.65), contralateral stroke (1.0% vs. 0.1%, P = 0.07), and death (1.0% vs. 1.2%, P > 0.99) were similar between modalities. None of these endpoints, including a composite of stroke and death (4.8% vs. 3.6%, P = 0.38), reached statistical significance. Additionally, we found no differences with respect to stroke-free survival between modalities during follow-up by Kaplan-Meier analysis (P = 0.30). CONCLUSIONS: In this combined experience from 2 large health systems, TCAR was associated with less intraoperative complexity, as measured by operative time, radiation exposure, and contrast volume. Although stroke and death seemed to be less frequent in patients undergoing transcervical stenting, this did not reach statistical significance.

Neotropical Rattlesnake (Crotalus simus) Venom Pharmacokinetics in Lymph and Blood Using an Ovine Model.

The most abundant protein families in viper venoms are Snake Venom Metalloproteases (SVMPs), Snake Venom Serine Proteases (SVSPs) and Phospholipases (PLA2s). These are primarily responsible for the pathophysiology caused by the bite of pit-vipers; however, there are few studies that analyze the pharmacokinetics (PK) of whole venom (WV) and its protein families. We studied the pathophysiology, PK profile and differential absorption of representative toxins from venom of Neotropical Rattlesnake (Crotalus simus) in a large animal model (ovine). Toxins studied included crotoxin (the main lethal component), which causes moderate to severe neurotoxicity; SVSPs, which deplete fibrinogen; and SVMPs, which cause local tissue damage and local and systemic hemorrhage. We found that Whole Venom (WV) was highly bioavailable (86%) 60 h following intramuscular (IM) injection, and extrapolation suggests that bioavailability may be as high as 92%. PK profiles of individual toxins were consistent with their physicochemical properties and expected clinical effects. Lymph cannulated animals absorbed 1.9% of WV through lymph during the first 12 h. Crotoxin was minimally detectable in serum after intravenous (IV) injection; however, following IM injection it was detected in lymph but not in blood. This suggests that crotoxin is quickly released from the blood toward its tissue targets.

Functional, proteomic and transcriptomic characterization of the venom from Micrurus browni browni: Identification of the first lethal multimeric neurotoxin in coral snake venom.

Proteomic characterization of Micrurus browni browni venom showed approximately 41 components belonging to 9 protein families, mainly phospholipases A2 (PLA2s) and three-finger toxins (3FTxs). Venom gland transcriptome yielded 39 venom transcripts belonging to 10 protein families. Functional characterization identified a multimeric toxin, here designated Brownitoxin-1, which comprises at least one PLA2 and one 3FTx. Its components have no or very low lethality individually but become extremely lethal when combined; both were partially characterized. Other two lethal components were identified: A neurotoxic PLA2, and a postsynaptic α-neurotoxin. LD50s as well as PLA2 and nAChR-blocking activities were determined for whole venom and isolated components. Application of venom to murine neuromuscular preparations caused a progressive decrease of twitch force that was irreversible after washing. Inhibition of PLA2 activity with p-bromophenacyl bromide (pBPB) showed that approximately 90% of toxicity is dependent on this activity. Non-lethal components include diverse 3FTxs, at least three enzymatically active PLA2s and the nociceptive toxin MitTx. No evidence of specificity towards prey was observed. This work is one of the most complete characterizations of a coral snake venom so far and its findings highlight the relevance of protein complexes in venom function. SIGNIFICANCE: This study represents a profound analysis of the venom of the coral snake Micrurus browni browni, including a venom proteome, venom gland transcriptomic data and functional studies of whole venom and isolated toxins. It significantly contributes to the understanding of North American coral snake venoms, which are currently largely unknown. It includes characterization of relevant venom components, one of which represents the first description of a lethal multimeric neurotoxin in coral snake venom. This work highlights the importance of protein complexes in coral snake venom and could serve as a basis for the finding of several other multimeric toxins. Finally, we report the absence of taxon specificity, which has been previously reported in the venoms of other snakes of the same genus.

Prognostic Value of the Pretreatment Neutrophil-to-Lymphocyte Ratio in Different Phenotypes of Locally Advanced Breast Cancer During Neoadjuvant Systemic Treatment.

PURPOSE: Neutrophils are among the key cellular players in the inflammatory milieu produced in patients with breast cancer (BC), and strong evidence exists in terms of the prognostic value of assessing the neutrophil-to-lymphocyte ratio (NLR) in patients with BC. In this study we sought to determine whether the baseline NLR correlates with pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS) in patients with locally advanced BC in the neoadjuvant chemotherapy (NAC) setting. METHODS: We analyzed the pretreatment NLR from the first blood count of patients treated from 2007 to 2015 in terms of pCR, DFS, and OS in patients with locally advanced BC. Patients received standard medical care based on national guidelines. RESULTS: A total of 1519 patients were included in the study. Median age was 49 years (22-88). The cutoff point for NLR was 2.0. NLR was not associated with pCR or DFS. However, patients with high NLR had worse OS in the presence of triple-negative BC (105.9 months; 95% confidence interval [CI], 100.2-111.5] vs. 98.7 months; 95% CI, 91.1-106.3; P = .029), Her2 overexpression (114.0 months; 95% CI, 110.5-118.0 vs. 100.8 months; 95% CI 95.7-105.9; P = .019), and residual disease after NAC for both phenotypes. Multivariate analysis showed that NLR was independently associated with OS (hazard ratio, 1.4; 95% CI, 1.02-1.95; P = .037). CONCLUSIONS: Pretreatment NLR in patients with locally advanced BC correlates with OS as an independent prognostic factor. This influence depends on phenotype and residual disease. Routine assessment of this parameter could be an easy and affordable tool for defining prognosis.

BDNF induces in vivo long-lasting enhancement of synaptic transmission and structural reorganization at the hippocampal mossy fibers in a transcription and translation-independent manner.

Brain-derived neurotrophic factor (BDNF) is an essential product of protein synthesis with a prominent impact on brain signaling and synaptic plasticity. Exogenous application of this neurotrophin is able to induce long-term potentiation (LTP) in several brain structures such as the hippocampus along with increases in gene transcription and translation of proteins involved in functional and structural plasticity. In this regard, our previous studies have demonstrated that acute intrahippocampal administration of BDNF induces long-lasting enhancement of synaptic transmission at the mossy fibers projection (MF) accompanied by a structural reorganization at the CA3 hippocampus area. Thus, considering the non-canonical molecular mechanisms underlying MF-CA3-LTP and the high expression of this neurotrophin in the CA3 area, we wonder whether transcriptional and translational inhibition interferes with the persistence of the MF functional and structural synaptic plasticity elicited by BDNF in adult rats in vivo. Our results show that BDNF is able to induce a lasting potentiation of synaptic efficacy at the MF projection accompanied by a structural reorganization at the CA3 area in an mRNA synthesis and protein translation-independent manner. The present findings support the idea that BDNF is an essential plasticity related product, which is necessary and sufficient to induce and maintain functional and structural synaptic plasticity at the MF-CA3 pathway.

Consolidation of an aversive taste memory requires two rounds of transcriptional and epigenetic regulation in the insular cortex.

The current view of the neurobiology of learning and memory suggests that long-term memory (LTM) depends not only on the de novo protein synthesis but also on the synthesis of mRNA even hours after the acquisition of memory, as well as that the regulation of transcription through the histone acetylation is essential for the memory establishment. Our previous studies showed that protein synthesis inhibition around the time of training and 5-7 hours after acquisition in the insular cortex (IC) prevents the consolidation of conditioned taste aversion (CTA), a well-established learning and memory paradigm in which an animal learns to associate a novel taste with nausea. However, the participation of mRNA synthesis and the epigenetic regulation through histone acetylation in this process remains unexplored. In the present study we evaluated the effect of the inhibition of transcription as well as deacetylation of histones at two temporal windows on the consolidation of CTA. Thus, immediately or seven hours after CTA acquisition animals received a microinfusion of 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) or MS-275 in the IC, respectively. The present results show that transcription inhibition immediately and 7 h after acquisition impairs the CTA memory consolidation, whereas the inhibition of histone deacetylation strengths this memory at those temporal windows. These findings reveal that CTA memory requires recurrent rounds of transcriptional modulation events in the IC in order to consolidate this memory trace, demonstrating that transcriptional and epigenetic modulation substantially contribute to memory-consolidation-related functions performed by a neocortical area even several hours after memory acquisition.

Extinction of aversive taste memory homeostatically prevents the maintenance of in vivo insular cortex LTP: Calcineurin participation.

Accumulating evidence indicates that homeostatic plasticity mechanisms dynamically adjust synaptic strength to promote stability that is crucial for memory storage. Our previous studies have shown that prior training in conditioned taste aversion (CTA) prevents the subsequent induction of long-term potentiation (LTP) in the projection from the basolateral nucleus of the amygdala (Bla) to the insular cortex (IC) in vivo. We have also reported that induction of LTP in the Bla-IC pathway modifies the CTA extinction. Memoryextinction involves the formation of a new associativememorythat inhibits a previously conditioned association. The aim of the present study was to analyze the effect of CTA extinction on the ability to induce subsequent LTP in the Bla-IC projection in vivo. Thus, 48 h after CTA extinction animals received high frequency stimulation in order to induce IC-LTP. Our results show that extinction training allows the induction but not the maintenance of IC-LTP. In addition, with the purpose of exploring part of the mechanisms involved in this process and since a body of evidence suggests that protein phosphatase calcineurin (CaN) is involved in the extinction of some behavioral tasks, we analyzed the participation of this phosphatase. The present results show that extinction training increases the CaN expression in the IC, as well as that the inhibition of this phosphatase reverts the effects of the CTA-extinction on the IC-LTP. These findings reveal that CTA extinction promotes a homeostatic regulation of subsequent IC synaptic plasticity maintenance through increases in CaN levels.

Recombinant-phospholipase A2 production and architecture of inclusion bodies are affected by pH in Escherichia coli.

Aggregation of recombinant proteins into inclusion bodies (IBs) is the major drawback of heterologous expression in Escherichia coli. Here, we evaluated the effects of a pH shift after expression induction on recombinant phospholipase A2 production and its aggregation in IBs in E. coli Origami™, as compared to cultures with pH maintained at 7.5 or uncontrolled pH. Cultures shifted from 7.5 to pH 6.5 or 8.5 produced ∼15-25% less biomass as compared with those kept at 7.5 or without pH control. The cultures shifted to pH 8.5 showed a ∼50% higher yield of acetate per biomass, and the rPLA2 yield was improved 2.4-fold. Purified IBs formed at pH 8.5 containing ∼50% of rPLA2, were more susceptible to proteinase-K cleavage and bound less thioflavin-T, indicating lower amyloid content, with the concomitant enrichment of α-helical and random-coil secondary structures, as demonstrated by FTIR. Moreover, only one IB per cell was formed at pH 8.5; instead, more than two were observed under the other culture pH conditions. Nevertheless, under uncontrolled pH conditions, ∼300nm larger IBs were observed. Our work presents evidence of the usefulness of recombinant protein expression cultivated at pH 8.5 allowing the reduction of amyloid content in IBs.

Production of a recombinant phospholipase A2 in Escherichia coli using resonant acoustic mixing that improves oxygen transfer in shake flasks.

BACKGROUND: Shake flasks are widely used during the development of bioprocesses for recombinant proteins. Cultures of recombinant Escherichia coli with orbital mixing (OM) have an oxygen limitation negatively affecting biomass growth and recombinant-protein production. With the aim to improve mixing and aeration in shake flask cultures, we analyzed cultures subjected to OM and the novel resonant acoustic mixing (RAM) by applying acoustic energy to E. coli BL21-Gold (DE3): a producer of recombinant phospholipase A2 (rPLA2) from Micrurus laticollaris snake venom. RESULTS: Comparing OM with RAM (200 rpm vs. 7.5g) at the same initial volumetric oxygen transfer coefficient (kLa ≈ 80 h-1) ~69% less biomass was obtained with OM compared with RAM. We analyzed two more conditions increasing agitation until maximal speed (12.5 and 20g), and ~1.6- and ~1.4-fold greater biomass was obtained as compared with cultures at 7.5g. Moreover, the specific growth rate was statistically similar in all cultures carried out in RAM, but ~1.5-fold higher than that in cultures carried out under OM. Almost half of the glucose was consumed in OM, whereas between 80 and 100% of the glucose was consumed in RAM cultures, doubling biomass per glucose yields. Differential organic acid production was observed, but acetate production was prevented at the maximal RAM (20g). The amount of rPLA2 in both, OM and RAM cultures, represented 38 ± 5% of the insoluble protein. A smaller proportion of α-helices and ß-sheet of purified inclusion bodies (IBs) were appreciated by ATR-FTIR from cultures carried out under OM, than those from RAM. At maximal agitation by RAM, internal E. coli localization patterns of protein aggregation changed, as well as, IBs proteolytic degradation, in conjunction with the formation of small external vesicles, although these changes did not significantly affect the cell survival response. CONCLUSIONS: In moderate-cell-density recombinant E. coli BL21-Gold (DE3) cultures, the agitation increases in RAM (up to the maximum) was not enough to avoid the classical oxygen limitation that happens in OM shake flasks. However, RAM presents a decrease of oxygen limitation, resulting in a favorable effect on biomass growth and volumetric rPLA2 production. While under OM a higher recombinant protein yield was obtained.

CaMKII requirement for the persistence of in vivo hippocampal mossy fiber synaptic plasticity and structural reorganization.

CaMKII has been proposed as a molecular substrate for long-term memory storage due to its capacity to maintain an active autophosporylated state even after the decay of the external stimuli. The hippocampal mossy fiber-CA3 pathway (MF-CA3) is considered as a relevant area for acquisition and storage of different learning tasks. MF-CA3 pathway exhibits a form of LTP characterized by a slow initial increase in the EPSP slope that is independent of NMDA receptors activation. Our previous studies show that application of high frequency stimulation sufficient to elicit MF-CA3 LTP produces structural reorganization, in a manner independent of LTP induction, at the stratum oriens of hippocampal CA3 area 7days after stimulation. However, the molecular mechanisms that underlie the maintenance of MF-CA3 LTP as well as the concomitant structural reorganization in this area remain to be elucidated. Here we show that acute microinfusion of myr-CaMKIINtide, a noncompetitive inhibitor of CaMKII, in the hippocampal CA3 area of adult rats during the late-phase of in vivo MF-CA3 LTP blocked its maintenance and prevented the accompanying morphological reorganization in CA3 area. These findings support the idea that CaMKII is a key molecular substrate for the long-term hippocampal synaptic plasticity maintenance.

Conditioned taste aversion prevents the long-lasting BDNF-induced enhancement of synaptic transmission in the insular cortex: A metaplastic effect.

Homeostatic plasticity mechanisms dynamically adjust synaptic strengths to promote stability that is crucial for memory storage. Metaplasticity is an example of these forms of plasticity that modify the capacity of synapses to experience subsequent Hebbian modifications. In particular, training in several behavioral tasks modifies the ability to induce long-term potentiation (LTP). Recently, we have reported that prior training in conditioned taste aversion (CTA) prevents the subsequent induction of LTP generated by high frequency stimulation in the projection from the basolateral nucleus of the amygdala (Bla) to the insular cortex (IC). One of the key molecular players that underlie long-term synaptic plasticity is brain-derived neurotrophic factor (BDNF). Previous studies from our group reported that acute microinfusion of BDNF in the IC induces a lasting potentiation of synaptic efficacy at the Bla-IC projection. Thus, the aim of the present study was to analyze whether CTA training modifies the ability to induce subsequent BDNF-induced potentiation of synaptic transmission in the Bla-IC projection in vivo. Accordingly, CTA trained rats received intracortical microinfusion of BDNF in order to induce lasting potentiation 48h after the aversion test. Our results show that CTA training prevents the induction of in vivo BDNF-LTP in the Bla-IC projection. The present results provide evidence that CTA modulates BDNF-dependent changes in IC synaptic strength.

Influence of pH control in the formation of inclusion bodies during production of recombinant sphingomyelinase-D in Escherichia coli.

BACKGROUND: Inclusion bodies (IBs) are aggregated proteins that form clusters when protein is overexpressed in heterologous expression systems. IBs have been considered as non-usable proteins, but recently they are being used as functional materials, catalytic particles, drug delivery agents, immunogenic structures, and as a raw material in recombinant therapeutic protein purification. However, few studies have been made to understand how culture conditions affect the protein aggregation and the physicochemical characteristics that lead them to cluster. The objective of our research was to understand how pH affects the physicochemical properties of IBs formed by the recombinant sphingomyelinase-D of tick expressed in E. coli BL21-Gold (DE3) by evaluating two pH culture strategies. RESULTS: Uncontrolled pH culture conditions favored recombinant sphingomyelinase-D aggregation and IB formation. The IBs of sphingomyelinase-D produced under controlled pH at 7.5 and after 24 h were smaller (<500 nm) than those produced under uncontrolled pH conditions (>500 nm). Furthermore, the composition, conformation and ß-structure formation of the aggregates were different. Under controlled pH conditions in comparison to uncontrolled conditions, the produced IBs presented higher resistance to denaturants and proteinase-K degradation, presented ß-structure, but apparently as time passes the IBs become compacted and less sensitive to amyloid dye binding. CONCLUSIONS: The manipulation of the pH has an impact on IB formation and their physicochemical characteristics. Particularly, uncontrolled pH conditions favored the protein aggregation and sphingomyelinase-D IB formation. The evidence may lead to find methodologies for bioprocesses to obtain biomaterials with particular characteristics, extending the application possibilities of the inclusion bodies.

Intraspecific differences in the immunochemical reactivity and neutralization of venom from Argentinean Bothrops (Rhinocerophis) alternatus by specific experimental antivenoms.

The venoms of Bothrops (Rhinocerophis) alternatus (B.a.) from different regions of Argentina have shown biochemical, toxicological and immunological variations. Considering these variations, we produced nine experimental antisera (rabbit, IgG) against venoms from snakes of nine different regions and a pool of venom, comprised of equal amounts of venoms from each region. The immunologic studies (ELISA, Westernblot) showed significant cross reactivity among all regional antivenoms with all regional venoms, with no significant differences regarding the specificity of the immunogens used for the production of antivenom. Neutralization of hemorrhage was variable (although all the antivenoms neutralized this activity in all venoms) and the neutralization of coagulant and phospholipase activities were evident in all cases. Some antivenoms neutralized toxic activities that were absent or very low in the venoms used as immunogen, on other non-homologous venoms (e.g. thrombin like activity). Despite the different toxic potencies of regional venoms, antivenoms developed using venoms of snakes from a particular region showed high immunochemical reactivity and cross-neutralizing capacity on snake venoms from different and distant regions, in occasions over those of the homologous antivenoms. These findings could be used to improve the generation of pools of venoms for the production of antivenoms.

Identification, cDNA cloning and heterologous expression of a hyaluronidase from the tarantula Brachypelma vagans venom.

Hyaluronidases (Hyal) present in the venom of poisonous animals have been considered as "spreading factors" that facilitate a fast penetration of the venom in the prey. We have found that hyaluronidase from the tarantula Brachypelma vagans venom (BvHyal) displays a substrate-specific Hyal activity against hyaluronan. By using a combined strategy based on peptide sequencing and RT-PCR, we have cloned a BvHyal cDNA. Active recombinant BvHyal was efficiently expressed in a baculovirus system in insect cell.

[Poland's syndrome. Case report]. / Síndrome de Poland. Informe de un caso.

OBJECTIVE: To report a case of Poland syndrome in a 67-year-old woman. CLINICAL CASE: The patient was questioned and examined for a history of malformations characteristic of this syndrome on a routine medical visit. Thorax, bone thorax, and comparative hand X-ray were taken. Mammary ultrasound, mastography, and computed axial tomography were taken also. The right hemithorax showed a thin subcutaneous cell tissue. Axillary alopecia, mammary hypoplasia and areola-nipple complex retraction, hypoplasia of major pectoral muscles was observed. In the right upper limb, there was forearm shortening, hypoplasia of the second phalanx in all five fingers, and absence of distal phalanx in the index finger. CONCLUSIONS: The patient showed 4 out of the 5 characteristics considered as typical by Hester and Bostwick. In terms of hand anomalies, she was classified as type 1 according to Gausewitz and according with Al-Qaifan, the patient belongs to type 2.