Alcohol Use and Abstinence throughout Adolescence: The Changing Contributions of Perceived Risk of Drinking, Opportunities to Drink, and Self-Control.

Objective: Adolescence is characterized by psychosocial and cognitive changes that can alter the perceived risk of negative effects of alcohol, opportunities to drink, and self-control. Few studies have investigated whether these factors change in their contribution to adolescent drinking over time. This study examined associations between perceived risk, opportunities to drink, self-control, and past-year drinking and investigated whether self-control buffers the effect of lower perceived risk and frequent drinking opportunities on the probability of past-year drinking. Method: Data from a four-wave longitudinal study (2015-2020) of 2,104 North Carolina adolescents (Mage = 12.36, SDage = 1.12, at Time 1) were used to assess changes in associations between self-control, perceived risk of drinking, and drinking opportunities on the frequency of past-year drinking. Hypotheses were tested using latent trajectory models. Results: At all timepoints, greater perceived risk, fewer drinking opportunities, and higher self-control were associated with drinking abstinence in the past year. Self-control buffered the impact of frequent drinking opportunities and lower perceived risk on the probability of alcohol use at Times 1-3. Conclusions: Despite expectations that adolescents' ability to navigate their environments improves as they age, associations between risk, protective factors, and past-year drinking were relatively stable over time. Nevertheless, self-control protected against frequent drinking opportunities and lower perceived risk. Strategies that support or relieve the need for self-control (e.g., situation modification) may protect against alcohol use throughout adolescence.

Electrochemical detection of poly(3-hydroxybutyrate) production from Burkholderia glumae MA13 using a molecularly imprinted polymer-reduced graphene oxide modified electrode.

The development and application of an electrochemical sensor is reported for detection of poly(3-hydroxybutyrate) (P3HB) - a bioplastic derived from agro-industrial residues. To overcome the challenges of molecular imprinting of macromolecules such as P3HB, this study employed methanolysis reaction to break down the P3HB biopolymer chains into methyl 3-hydroxybutyrate (M3HB) monomers. Thereafter, M3HB were employed as the target molecules in the construction of molecularly imprinted sensors. The electrochemical device was then prepared by electropolymerizing a molecularly imprinted poly (indole-3-acetic acid) thin film on a glassy carbon electrode surface modified with reduced graphene oxide (GCE/rGO-MIP) in the presence of M3HB. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy with field emission gun (SEM-FEG), Raman spectroscopy, attenuated total reflection Fourier-transform infrared (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS) were employed to characterize the electrode surface. Under ideal conditions, the MIP sensor exhibited a wide linear working range of 0.1 - 10 nM and a detection limit of 0.3 pM (n = 3). The sensor showed good repeatability, selectivity, and stability over time. For the sensor application, the bioproduction of P3HB was carried out in a bioreactor containing the Burkholderia glumae MA13 strain and sugarcane byproducts as a supplementary carbon source. The analyses were validated through recovery assays, yielding recovery values between 102 and 104%. These results indicate that this MIP sensor can present advantages in the monitoring of P3HB during the bioconversion process.

Genomic Dissection of an Enteroaggregative Escherichia coli Strain Isolated from Bacteremia Reveals Insights into Its Hybrid Pathogenic Potential.

Escherichia coli is a frequent pathogen isolated from bloodstream infections. This study aimed to characterize the genetic features of EC092, an E. coli strain isolated from bacteremia that harbors enteroaggregative E. coli (EAEC) genetic markers, indicating its hybrid pathogenic potential. Whole-genome sequencing showed that EC092 belongs to phylogroup B1, ST278, and serotype O165:H4. Genes encoding virulence factors such as fimbriae, toxins, iron-uptake systems, autotransporter proteins (Pet, Pic, Sat, and SepA), and secretion systems were detected, as well as EAEC virulence genes (aggR, aatA, aaiC, and aap). EC092 was found to be closely related to the other EAEC prototype strains and highly similar in terms of virulence to three EAEC strains isolated from diarrhea. The genomic neighborhood of pet, pic, sat, sepA, and the EAEC virulence genes of EC092 and its three genetically related fecal EAEC strains showed an identical genomic organization and nucleotide sequences. Also, EC092 produced and secreted Pet, Pic, Sat, and SepA in the culture supernatant and resisted the bactericidal activity of normal human serum. Our results demonstrate that the strain EC092, isolated from bacteremia, is a hybrid pathogenic extraintestinal E. coli (ExPEC)/EAEC with virulence features that could mediate both extraintestinal and intestinal infections.

Identity Matters: Multiple Herbivory Induces Less Attractive or Repellent Coffee Plant Volatile Emission to Different Natural Enemies.

Co-infestations by herbivores, a common situation found in natural settings, can distinctly affect induced plant defenses compared to single infestations. Related tritrophic interactions might be affected through the emission of changed blends of herbivore-induced plant volatiles (HIPVs). In a previous study, we observed that the infestation by red spider mite (Oligonychus ilicis) on coffee plants facilitated the infestation by white mealybug (Planococcus minor), whereas the reverse sequence of infestation did not occur. Here, we examined the involvement of the jasmonate and salicylate pathways in the plant-mediated asymmetrical facilitation between red spider mites and white mealybugs as well as the effect of multiple herbivory on attractiveness to the predatory mite Euseius concordis and the ladybug Cryptolaemus montrouzieri. Both mite and mealybug herbivory led to the accumulation of JA-Ile, JA, and cis-OPDA in plants, although the catabolic reactions of JA-Ile were specifically regulated by each herbivore. Infestation by mites or mealybugs induced the release of novel volatiles by coffee plants, which selectively attracted their respective predators. Even though the co-infestation by mites and mealybugs resulted in a stronger accumulation of JA-Ile, JA and SA than the single infestation treatments, the volatile emission was similar to that of mite-infested or mealybug-infested plants. However, multiple infestation had a negative impact on the attractiveness of HIPVs to the predators, making them less attractive to the predatory mite and a repellent to the ladybug. We discuss the potential underlying mechanisms of the susceptibility induced by mites, and the effect of multiple infestation on each predator.

Platelets in dengue infection: more than a numbers game.

Dengue virus (DENV) infection is responsible for the development of dengue illness, which can be either asymptomatic, present mild manifestations or evolve to severe dengue. Thrombocytopenia is an important characteristic during DENV infection, being observed both in mild and severe dengue, although the lowest platelet counts are encountered during severe cases. This review gathers information regarding several mechanisms that have been related to alterations in platelet number and function, leading to thrombocytopenia but also platelet-mediated immune and inflammatory response. On this regard, we highlight that the decrease in platelet counts may be due to bone marrow suppression or consumption of platelets at the periphery. We discuss the infection of hematopoietic progenitors and stromal cells as mechanisms involved in bone marrow suppression. Concerning peripheral consumption of platelets, we addressed the direct infection of platelets by DENV, adhesion of platelets to leukocytes and vascular endothelium and platelet clearance mediated by anti-platelet antibodies. We also focused on platelet involvement on the dengue immunity and pathogenesis through translation and secretion of viral and host factors and through platelet-leukocyte aggregates formation. Hence, the present review highlights important findings related to platelet activation and thrombocytopenia during dengue infection, and also exhibits different mechanisms associated with decreased platelet counts.Graphical abstract:Schematic mechanistic representation of platelet-mediated immune responses and thrombocytopenia during dengue infection. (A) DENV-infected platelets secrete cytokines and chemokines and also adhere to activated vascular endothelium. Platelets aggregate with leukocytes, inducing the secretion of NETs and inflammatory mediators by neutrophils and monocytes, respectively. (B) DENV directly infects stromal cells and hematopoietic precursors, including megakaryocytes, which compromises megakaryopoiesis. Both central and peripheric mechanisms contribute to DENV-associated thrombocytopenia.

Virulence markers, adhesion and biofilm formation of Escherichia coli strains isolated from drinking water supplies of north Paraná State, Brazil.

Waterborne diseases are a major public health problem responsible for a high number of deaths worldwide, of which Escherichia coli is a major agent of contamination. This study investigates the occurrence of different diarrheagenic E. coli (DEC) pathotypes and its relationship with adherence patterns and biofilm formation. Between 2012 and 2014, a total of 1,780 drinking water samples were collected from different rural communities and urban water systems of north Paraná State. A total of 14% were positive for E. coli and 250 non-duplicate E. coli isolates were obtained. Between the E. coli isolates, 28 (11.2%) harbored DEC-associated genes, 10.7% being classified as Shiga toxin-producing E. coli (STEC), 64.3% enteroaggregative E. coli (EAEC) and 25% atypical enteropathogenic E. coli (aEPEC). The aggregative adherence (AA) was the predominant adherence pattern (84%), significantly associated with biofilm formation (p < 0.0001). On the other hand, the AA pattern and biofilm formation were not significantly associated to DEC pathotypes (p > 0.05). Therefore, we proposed that the AA pattern and biofilm formation in E. coli isolated from drinking water supplies could be associated with adherence and colonization of abiotic surfaces, such as pipes, leading to persistence and resistance to treatment or disinfection.

Navigating Still Waters of Infertility: Role of Goal Features in Coping with a Thwarted Goal.

BACKGROUND: The infertility experience is often surrounded by frustration and discouragement associated with the thwarted goal to have a child. Though research has identified commonly used strategies to cope with infertility, this study is the first to examine how different goal attributes and processes associated with the experience of infertility relate to coping strategy use and psychological distress. METHOD: Women (N = 353) recruited from online support forums reported on the nature of their goal to have a child, their psychological distress, and their use of strategies to cope with the failure to achieve that goal. RESULTS: Women reported high striving toward a goal high in importance and commitment, coupled with high goal-related stress and feeling that achievement is blocked. Consistent with the notion that coping strategy use is specific to the features of the experience, no single goal attribute nor combination of attributes consistently accounted for coping strategy use, suggesting that the latter may be specific to the cognitions and processes of pursuit of the goal to have a child. With one exception, perceptions of impediment were better predictors of psychological distress than any level of perceived facilitators of goal pursuit, positing potential targets for future psychological interventions. CONCLUSION: Understanding how women cope with infertility may require a detailed conceptualization of their goal to have a child. In the present sample, dynamic processes and coping strategies that otherwise detract from success were generally beneficial by providing alternatives to the pursuit of a thwarted goal.

Meta-analysis of early adolescent self-regulation interventions: Moderation by intervention and outcome type.

INTRODUCTION: Self-regulation has been identified as a highly promising target for interventions promoting broad wellbeing across development; however, there appear to be notable limitations in efficacy for early adolescents in particular. One possible reason is that the emotion regulation needs of youth have not been intentionally targeted in many interventions for this age group. The aim of this study is to advance understanding of how different intervention approaches defined from a clear theoretical model may impact different types of outcomes and with regard to different types of measures. METHODS: We conducted a systematic literature review of four databases using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and identified 33 studies of early adolescents (aged 10-15) using five different intervention approaches that were methodologically rigorous (e.g., randomized controlled trial design with low risk of bias). Studies were conducted predominantly in North America (58%), and Western Europe (30%). RESULTS: A two-level mixed-effects meta-analysis indicated a small but significant overall intervention effect (Hedges g = 0.12). When examined by intervention type, effects were significant only for approaches focusing predominantly on emotion regulation (g = 0.20), which significantly improved behavioral outcomes as well as emotional outcomes. Approaches examining cognitive regulation, parent training, physical activity, and working memory did not differ significantly from zero. Across intervention types, outcomes demonstrated the largest effects for youth report of emotional distress. CONCLUSION: Overall, results suggest that emotion regulation may be a critically important self-regulation mechanism during early adolescence and demonstrates value in the use of applied theoretical frameworks to operationalize intervention approaches and outcomes.

Role of nicergoline in corneal wound healing in diabetic rats.

BACKGROUND: To investigate the effect of nicergoline on the rate of complete corneal ulcer reepithelialization (CCUR) in diabetic rats with diabetic keratopathy. METHODS: Forty-eight streptozotocin-induced diabetic rats were randomly divided into two groups. The experimental group (n = 24) received nicergoline (10 mg.kg- 1.day- 1), while the control group (n = 24) received a placebo. A corneal epithelial defect was induced using a corneal diamond burr, and defect area was compared at time points of 0, 12, 24, 48 and 72 h after the injury using image analysis software. The probability of CCUR within 72 h was assessed using the Kaplan-Meier survival analysis log-rank test. RESULTS: When compared, 4 of the 24 rats (17%) in the placebo group and 12 of the 24 rats (50%) in the nicergoline group were found to have CCUR within 72 h (log-rank = 0.027). Cox regression analysis found no effect of the covariates blood glucose (P = 0.601) or weight (P = 0.322) on the corneal reepithelialization (survival) curve. CONCLUSIONS: Nicergoline increased wound healing rates relative to placebo and may therefore be investigated as a treatment option in diabetic keratopathy.

Additive or Multiplicative? Predicting Academic Outcomes from Self-Regulation and Context.

Many studies have documented the role of self-regulation in predicting academic outcomes. However, fewer have comprehensively measured self-regulation or considered it simultaneously with contextual variables to test formally the often-advanced "risk-buffering" hypothesis, wherein self-regulatory skill protects against contextual risk factors. In a large, regionally representative sample of U.S. adolescents, we linked self-reported demographics, self-regulation, and academic outcomes to Census data assessing neighborhood context and administrative data measuring economic disadvantage and achievement levels on state end-of-grade tests. We find inconsistent evidence for a risk-buffering role of self-regulation in the prediction of academic outcomes. Rather, we demonstrate that self-regulation is independently associated with academic outcomes, even when controlling for demographics and context.

Brazilian cardio-oncology: the 10-year experience of the Instituto do Cancer do Estado de Sao Paulo.

BACKGROUND: In recent years, the field of cardio-oncology has grown worldwide, bringing benefits to cancer patients in terms of survival and quality of life. This study reports the experience of a pioneer cardio-oncology programme at University Cancer Hospital in Brazil over a period of 10 years, describing the clinical profile of patients and the clinical outcomes. METHODS: A retrospective study was conducted on a cohort of patients treated at the cardio-oncology programme from April 2009 to February 2019. We analysed the characteristics of patients and outcomes, including mortality, according to the type of clinical indication for outpatient care (general cardiology, perioperative evaluation and follow-up and treatment cardiotoxicity). RESULTS: From a total of 26,435 medical consultations, we obtained the data of 4535 individuals among the medical care outpatients. When we analysed the clinical characteristics of patients considering the clinical indication - general cardiology, perioperative evaluation and cardiotoxicity outpatient clinics, differences were observed with respect to age (59 [48-66], 66 [58-74] and 69 [62-76], p < 0.001), diabetes (67 [15%], 635 [22.6%] and 379 [29.8%]; p < 0.001), hypertension (196 [43.8%], 1649 [58.7%] and 890 [70.1%], p < 0.001) and dyslipidaemia (87 [19.7%), 735 [26.2%] and 459 [36.2%], p < 0.001). A similar overall mortality rate was observed in the groups (47.5% vs. 45.7% vs. 44.9% [p = 0.650]). CONCLUSION: The number of oncologic patients in the Cardio-Oncology Programme has grown in the last decade. A well-structured cardio-oncology programme is the key to achieving the true essence of this area, namely, ongoing care for cancer patients throughout the disease treatment process, optimizing their cardiovascular status to ensure they can receive the best therapy against cancer.

Simvastatin-loaded polymeric micelles are more effective and less toxic than conventional statins in a pre-clinical model of advanced chronic liver disease.

Chronic liver disease (CLD) has no effective treatments apart from reducing its complications. Simvastatin has been tested as vasoprotective drug in experimental models of CLD showing promising results, but also limiting adverse effects. Two types of Pluronic® carriers loading simvastatin (PM108-simv and PM127-simv) as a drug delivery system were developed to avoid these toxicities while increasing the therapeutic window of simvastatin. PM127-simv showed the highest rates of cell internalization in rat liver sinusoidal endothelial cells (LSECs) and significantly lower toxicity than free simvastatin, improving cell phenotype. The in vivo biodistribution was mainly hepatic with 50% of the injected PM found in the liver. Remarkably, after one week of administration in a model of CLD, PM127-simv demonstrated superior effect than free simvastatin in reducing portal hypertension. Moreover, no signs of toxicity of PM127-simv were detected. Our results indicate that simvastatin targeted delivery to LSEC is a promising therapeutic approach for CLD.

Zileuton™ loaded in polymer micelles effectively reduce breast cancer circulating tumor cells and intratumoral cancer stem cells.

Tumor recurrence, metastatic spread and progressive gain of chemo-resistance of advanced cancers are sustained by the presence of cancer stem cells (CSCs) within the tumor. Targeted therapies with the aim to eradicate these cells are thus highly regarded. However, often the use of new anti-cancer therapies is hampered by pharmacokinetic demands. Drug delivery through nanoparticles has great potential to increase efficacy and reduce toxicity and adverse effects. However, its production has to be based on intelligent design. Likewise, we developed polymeric nanoparticles loaded with Zileuton™, a potent inhibitor of cancer stem cells (CSCs), which was chosen based on high throughput screening. Its great potential for CSCs treatment was subsequently demonstrated in in vitro and in in vivo CSC fluorescent models. Encapsulated Zileuton™ reduces amount of CSCs within the tumor and effectively blocks the circulating tumor cells (CTCs) in the blood stream and metastatic spread.

NO donors induce vascular relaxation by different cellular mechanisms in hypertensive and normotensive rats.

PURPOSE: This study investigated the intracellular mechanisms involved in the vasodilatation induced by the classic NO donor SNP and the non-classic NO donor cis-[Ru(bpy)2(py)(NO2)](PF6) (or RuBPY) in mesenteric resistance arteries obtained from renal hypertensive (2K-1C) and normotensive (2K) rats. METHODS: On the basis of fluorimetric assays in cultured vascular smooth muscle cells (VSMCs) isolated from 2K-1C and 2K rats, we measured NO release from SNP and RuBPY, cytosolic Ca2+ concentration ([Ca2+]c), and reactive oxygen species (ROS) with the selective probes DAF-2DA, Fluo-3AM and the more selective probe for peroxynitrite (7-CBA), respectively. We determined isometric tension in mesenteric arteries to assess SNP- and RuBPY-induced relaxation. RESULTS: SNP and RuBPY released NO in comparable amounts in cultured aortic VSMCs from hypertensive 2K-1C and normotensive 2K rats. The NO0 scavenger hydroxocobalamin blunted NO release. Sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) inhibition with thapsigargin reduced [Ca2+]c in normotensive 2K rat VSMCs only. ROS amounts were greater in hypertensive 2K-1C than in normotensive 2K rat VSMCs, but neither SNP nor RuBPY altered ROS concentrations in any of the groups. SNP and RuBPY induced similar relaxation in hypertensive 2K-1C and normotensive 2K rat mesenteric resistance arteries. The SNP and RuBPY-induced relaxation involves sGC and PKG activation. On the other hand, SNP but not RuBPY activates K+ channels. Interestingly, SERCA inhibition reduces SNP induced relaxation only in normotensive 2K rat mesenteric arteries whereas RuBPY-induced relaxation does not involve SERCA activation in both normotensive and hypertensive arteries. CONCLUSION: Our results indicate that SNP and RuBPY-induced mesenteric resistance artery relaxation involves NO/sGC/cGMP/PKG pathway activation. K+ channels and SERCA activation is required to SNP but not for RuBPY-induced relaxation. Moreover, SERCA seems to be impaired in hypertensive 2K-1C rat mesenteric resistance arteries although it does not impact SNP- or RuBPY-induced relaxation.

Spray-Dried Yerba Mate Extract Capsules: Clinical Evaluation and Antioxidant Potential in Healthy Individuals.

The aim of the present study was to evaluate the clinical effects and antioxidant potential of spray-dried yerba mate extract (SDME) capsules in healthy individuals. Fourteen healthy volunteers consumed three capsules of SDME three times daily. Measurements were carried out at the baseline and after 7, 30, and 60 days of SDME capsules intake. Electrocardiogram, hematological, urinary, and biochemical parameters analyzed remained within the normal values during all the study. SDME capsules ingestion increased significantly serum antioxidant capacity (after 7 and 30 days) and reduced glutathione values (after 7 and 60 days), and the superoxide dismutase (after 7, 30, and 60 days), catalase (after 7 and 30 days), and paraoxonase-1 activities (after 7 days); and decreased lipid hydroperoxides (after 30 and 60 days) and thiobarbituric acid reactive substances levels (after 7 and 30 days). No change was observed for glutathione peroxidase activity after SDME capsules intake. The present study showed that SDME capsules ingestion by healthy individuals did not promote clinical changes and promoted an increase of antioxidant biomarkers with a concomitant decrease of lipid peroxidation biomarkers in a short and prolonged manner.

Temporal arachnoid cysts: are they congenital?

CASE REPORT: The authors report two cases of arachnoid cysts (ACs) neither detected during pregnancy nor shortly after birth when newborns underwent CT scan evaluation after birth head trauma. ACs were diagnosed at 10 months and 6 years, respectively. The first one becomes symptomatic, and the other one was incidentally found during a head trauma investigation. DISCUSSION: These cases give support for the postnatal pathogenesis for some of the assumed congenital ACs. We collected data from the literature that supports the acquired hypothesis for ACs.

Assessing the effectiveness of nutrition interventions implemented among US college students to promote healthy behaviors: A systematic review.

BACKGROUND:: Nutrition interventions are used to increase knowledge, change attitudes and beliefs about healthy eating, to increase skills, and promote healthy eating. AIMS:: To review the effectiveness of published nutrition interventions implemented among college students to promote healthy behaviors. METHODS:: The authors explored multiple electronic databases, such as ERIC, Science Direct, and EBSCOhost. Search criteria included nutritional interventions implemented among students attending US colleges, written in English, and published in peer-reviewed journals between 2000 and 2015. The authors conducted a systematic search of 1413 articles, and an in-depth review of 30 articles. The authors evaluated the following: (a) participants; (b) research design; (c) assessment instruments; (d) outcome measures; (e) results; and (f) methodological issues. RESULTS:: Short-term interventions showed promise in promoting positive dietary changes, which can serve as a protective factor for developing overweight and obesity. Methodological issues related to lack of comparison groups and minimal long-term follow-up do not allow researchers to determine if the interventions were the cause of the change, or if these changes are sustained over time. Studies that have a comparison group, use visual displays, or have longer durations, may maximize outcomes, improving long-term effects. CONCLUSIONS:: Nutrition interventions can effectively change dietary habits among college students. This can lead to healthy weight management and reduce the risk for overweight and obesity. Future research should consider the highlighted methodological issues to improve the quality of nutrition interventions.

Hypotensive effect and vascular relaxation in different arteries induced by the nitric oxide donor RuBPY.

NO donors are compounds that release NO that can be used when the endogenous NO bioavailability is impaired. The compound cis-[Ru(bpy)2(py)(NO2)](PF6) (RuBPY) is a nitrite-ruthenium, since it has a NO2 in its molecule. The aim of the present study was to evaluate the effect of RuBPY on arterial pressure, as well as on the vascular relaxation of different vascular arteries in renal hypertensive (2K-1C) and normotensive (2K) rats. We have evaluated the arterial pressure and heart rate changes as well as the RuBPY and SNP-induced relaxation (thoracic aorta, mesenteric resistance, coronary and basilar arteries). The administration of RuBPY in awake rats evoked a smaller but long lasting hypotensive effect when compared to SNP, with no increase in heart rate. The relaxation induced by RuBPY was similar between 2K-1C and 2K rats in thoracic aorta, mesenteric resistance and coronary arteries. However, the relaxation induced by RuBPY was smaller in basilar arteries from 2K-1C than in 2K. Taken together, our results show that RuBPY presents several advantages over SNP, since it does not induce hypotensive effect in normotensive animals, the hypotensive effect is slower, with no reflex tachycardia, and it is long lasting. In addition, RuBPY induces coronary artery relaxation (useful for angina) and presented only a small effect on basilar artery (may not induce headache).

Hydrocephalus: a rare initial manifestation of sporadic intramedullary hemangioblastoma : Intramedullary hemangioblastoma presenting as hydrocephalus.

BACKGROUND: Intramedullary hemangioblastomas are rare benign vascular tumors, infrequent in pediatric patients. Clinical symptoms vary according to the age of presentation, tumor size, location, and concomitant syringomyelia. This is the second reported case of hemangioblastoma presenting with acute hydrocephalus. CASE PRESENTATION: A 3-month-old infant with acute hydrocephalus was asymptomatic after a ventriculoperitoneal shunt was placed. She returned 3 months later with irritability, acute paraplegia, and respiratory distress. Magnetic resonance imaging (MRI) showed an intramedullary T8-T9 tumor with syringomyelia. She underwent surgical resection with good results during the 6-month follow-up. CONCLUSION: Intramedullary tumors may present as hydrocephalus and other nonspecific symptoms, with invariably delayed diagnosis in children, but must be considered in suspicious cases.

Effect of the Freezing Step in the Stability and Bioactivity of Protein-Loaded PLGA Nanoparticles Upon Lyophilization.

PURPOSE: The freezing step in lyophilization is the most determinant for the quality of biopharmaceutics. Using insulin as model of therapeutic protein, our aim was to evaluate the freezing effect in the stability and bioactivity of insulin-loaded PLGA nanoparticles. The performance of trehalose, sucrose and sorbitol as cryoprotectants was evaluated. METHODS: Cryoprotectants were co-encapsulated with insulin into PLGA nanoparticles and lyophilized using an optimized cycle with freezing at -80°C, in liquid nitrogen, or ramped cooling at -40°C. Upon lyophilization, the stability of protein structure and in vivo bioactivity were assessed. RESULTS: Insulin was co-encapsulated with cryoprotectants resulting in particles of 243-394 nm, zeta potential of -32 to -35 mV, and an association efficiency above 90%. The cryoprotectants were crucial to mitigate the freezing stresses and better stabilize the protein. The insulin structure maintenance was evident and close to 90%. Trehalose co-encapsulated insulin-loaded PLGA nanoparticles demonstrated enhanced hypoglycemic effect, comparatively to nanoparticles without cryoprotectant and added with trehalose, due to a superior insulin stabilization and bioactivity. CONCLUSIONS: The freezing process may be detrimental to the structure of protein loaded into nanoparticles, with negative consequences to bioactivity. The co-encapsulation of cryoprotectants mitigated the freezing stresses with benefits to protein bioactivity.