Rheological Study of Phenol Formaldehyde Resole Resin Synthesized for Laminate Application

Heat explosions are sometimes observed during the synthesis of phenol formaldehyde (PF) resin. This scenario can be attributed to the high latent heat that was released and not dissipated leading to the occurrence of a runaway reaction. The synthesis temperature and time played important roles in controlling the heat release, hence preventing the resin from hardening during the synthesis process. This study aims to assess the rheological and viscoelasticity behaviors of the PF resin prepared using paraformaldehyde. The prepared PF resin was designed for laminate applications. The rheological behavior of the PF resin was assessed based on the different molar ratios of phenol to paraformaldehyde (P:F) mixed in the formulation. The molar ratios were set at 1.00:1.25, 1.00:1.50 and 1.00:1.75 of P to F, respectively. The rheological study was focused at specific synthesis temperatures, namely 40, 60, 80 and 100 °C. The synthesis time was observed for 240 min; changes in physical structure and viscosity of the PF resins were noted. It was observed that the viscosity values of the PF resins prepared were directly proportional to the synthesis temperature and the formaldehyde content. The PF resin also exhibited shear thickening behavior for all samples synthesized at 60 °C and above. For all PF resin samples synthesized at 60 °C and above, their viscoelasticity results indicated that the storage modulus (G′), loss modulus(G″) and tan δ are proportionally dependent on both the synthesis temperature and the formaldehyde content. Heat explosions were observed during the synthesis of PF resin at the synthesis temperature of 100 °C. This scenario can lead to possible runaway reaction which can also compromise the safety of the operators.

Glucocerebrosidase (GCase) activity modulation by 2-alkyl trihydroxypiperidines: Inhibition and pharmacological chaperoning

The enzyme glucocerebrosidase (GCase) has become an important therapeutic target due to its involvement in pathological disorders consequent to enzyme deficiency, such as the lysosomal storage Gaucher disease (GD) and the neurological Parkinson disease (PD). Pharmacological chaperones (PCs) are small compounds able to stabilize enzymes when used at sub-inhibitory concentrations, thus rescuing enzyme activity. We report the stereodivergent synthesis of trihydroxypiperidines alkylated at C-2 with both configurations, by means of the stereoselective addition of Grignard reagents to a carbohydrate-derived nitrone in the presence or absence of Lewis acids. All the target compounds behave as good GCase inhibitors, with IC₅₀ in the micromolar range. Moreover, compound 11a behaves as a PC in fibroblasts derived from Gaucher patients bearing the N370/RecNcil mutation and the homozygous L444P mutation, rescuing the activity of the deficient enzyme by up to 1.9- and 1.8-fold, respectively. Rescues of 1.2-1.4-fold were also observed in wild-type fibroblasts, which is important for targeting sporadic forms of PD.

Review and update on drugs related to the development of osteonecrosis of the jaw

Background

Medication-related osteonecrosis of the jaw (MRONJ) is a rare, but serious adverse effect of certain drugs, of which bisphosphonates are the most widely known. This pathology is also associated with other medications such as the biologic antiresorptive agent, denosumab and some antiangiogenics such as sunitinib, bevacizumab or aflibercept. Very recently, new medications have also been associated with osteonecrosis of the jaw (ONJ). The objectives were to update the list of medications associated with ONJ, to analyze the fundamental aspects of this list and to describe the level of evidence available.

Material and Methods

A narrative bibliographic review was made, using the PubMed-MedLine, DOAJ and SCIELO databases. Additional information was obtained through the online Medication Information Centre of the Spanish Agency of Medicines and Medical Devices (AEMPS – CIMA), the websites of the US Food & Drugs Administration (Drugs@FDA) and the European Medicines Agency (EMA).

Results

The latest drugs identified as potential facilitators of this pathology include a number of anti-VEGF based antiangiogenic drugs and anti-TKI and different types of immunomodulators. Neither the level of evidence in this association nor the risk are equal for all these drugs. On the other hand, over the coming years, new drugs will be marketed with similar action mechanisms to those that are recognized as having this adverse effect.

Conclusions

No effective therapy is currently known for the treatment of ONJ. Therefore, in order to prevent new cases of MRONJ, it is essential for all oral healthcare professionals to be fully up-to-date with the etiopathogenic aspects of this pathology and to be aware of those drugs considered to be a risk.

Key words:Osteonecrosis of the jaw, MRONJ, bisphosphonates, antiresorptives, antiangiogenics.

Antibodies to neuronal surface proteins in Tourette Syndrome: Lack of evidence in a European paediatric cohort

In Tourette Syndrome (TS) a role for autoantibodies directed against neuronal proteins has long been suspected, but so far results are still inconsistent. The aim of this study was to look for antibodies to specific or undefined neuronal proteins that could be involved in the aetiology of the disease. Sera from children with Tourette Syndrome or another chronic tic disorder (TS/TD), collected as part of the longitudinal European Multicenter Tics in Children Study, were investigated. Participants included 30 siblings of patients with TS/TD prior to developing tics (preclinical stage) and the same children after the first tic onset (onset), and 158 patients in the chronic phase undergoing an acute relapse (exacerbation). Presence of antibodies binding to rodent brain tissue was assessed by immunohistology on rat brain sections and by immunofluorescent staining of live hippocampal neurons. Live cell-based assays were used to screen for antibodies to NMDAR, CASPR2, LGI1, AMPAR and GABA_AR. Immunohistology indicated evidence of antibodies reactive with brain tissue, binding mainly to the hippocampus, the basal ganglia or the cerebellum in 26/218 (12%), with 8% of the preclinical or onset sera binding to the dentate gyrus/CA3 region or cerebellum. Only two individuals (one pre-clinical, one chronic) had antibodies binding the NMDAR and the binding was only weakly positive. No other specific antibodies were detected. Despite some immunoreactivity towards neuronal antigens on brain tissue, this was not mirrored by antibodies binding to live neurons, suggesting the presence of non-specific antibodies or those that bind non-pathogenic intracellular epitopes. NMDAR or the other neuronal surface antibodies tested were very infrequent in these patients. The evidence for pathogenic antibodies that could be causative of TS is weak.

Tunable Color of Aggregation-Induced Emission Enhancement in a Family of Hydrogen-Bonded Azines and Schiff Bases

A simple synthesis strategy afforded a family of hydrogen-bonded azines and Schiff-bases. Although in dilute solution these dyes are faint light emitters, all exhibit bright luminescence upon aggregation. Changing the peripheral substituents from electron donating to electron withdrawing allows emission fine-tuning in a range from bluish-green to orange-red. The crystal structures of the materials reveal that the restriction of intramolecular rotations is the main mechanism for the aggregation-induced emission enhancement properties.

Effect of increased opiate exposure on three years neurodevelopmental outcome in extremely preterm infants

BACKGROUND

International guidelines recommend the use of item based scales for the assessment of pain and sedation. In our previous study, the implementation of the Neonatal Pain Agitation and Sedation Scale (N-PASS), and the associated systematic assessment and treatment of pain and sedation reduced pain and over-sedation in our intervention group, but lead to a significant increase of individual opiate exposure. This increased opiate exposure was not associated with impaired motor and mental development at one year of age. As one-year follow-up is not necessarily representative for future outcomes, we retested our sample at three years of age.

METHODS

Fifty-three patients after (intervention group) and 61 before implementation (control group) of the N-PASS and the Vienna Protocol for the Management of Neonatal Pain and Sedation (VPNPS), were compared for motor, mental and behavioural development at three-years follow-up using the Bayley Scales of Infant Development.

RESULTS

Cumulative opiate exposure was not associated with mental (p = .31) and motor (p = .20) problems when controlling for other important medical conditions, but was associated to lower behavioural scores (p = .007). No statistically significant differences were found with regard to mental (p = .65), psychomotor (p = .12) and behavioural (p = .61) development before and after the implementation of the N-PASS and the VPNPS.

CONCLUSION

Implementing a neonatal pain and sedation protocol increased opiate exposure without affecting neurodevelopmental outcome at three-years of age.

Multimerization of DAB-1 onto Au GNPs affords new potent and selective N-acetylgalactosamine-6-sulfatase (GALNS) inhibitors

Gold glyconanoparticles (Au GNPs) decorated with the natural iminosugar DAB-1 at different densities are reported.

Molecular effect of fenofibrate on PBMC gene transcription related to lipid metabolism in patients with metabolic syndrome

BACKGROUND

Both fasting and postprandial hypertriglyceridaemia are considered independent risk factors for atherosclerosis. Treatment of hypertriglyceridaemia is based on fibrates, which activate the peroxisome proliferator-activated receptor alpha (PPARα). However, the metabolic pathways that activate or inhibit fibrates, and how the postprandial triglyceride levels are modified, have not yet been fully described. Accordingly, the aim of this study was to determine the feasibility of peripheral blood mononuclear cells (PBMC) to study the effects of fenofibrate in patients with the metabolic syndrome.

MATERIALS AND METHODS

A fat overload was given to 50 patients before and after treatment with fenofibrate for 3 months. Anthropometric and biochemical variables as well as gene expression in PBMC were analysed.

RESULTS

After treatment with fenofibrate, we observed a decrease in both baseline and postprandial (3 h after the fat overload) levels of serum triglycerides, cholesterol and uric acid and an increase in HDL cholesterol and apolipoprotein AI levels. After treatment, there was also a rise in PPARα and RXRα expression and changes in genes regulated by PPARα, both baseline and postprandial. Furthermore, in vitro experiments showed that a PPARα agonist changed the expression of genes related with lipid metabolism.

CONCLUSION

Treatment with fenofibrate reduced fasting and postprandial serum triglyceride levels, possibly through a mechanism related with an increase in the expression of RXRα and PPARα, by activating the pathways involved in the uptake and degradation of triglycerides and increasing the synthesis of apolipoprotein. These results suggest that PBMC may be useful for the easy study of fenofibrate actions.

Accessing 2-substituted piperidine iminosugars by organometallic addition/intramolecular reductive amination: aldehyde vs. nitrone route

A novel dual strategy to build 2-substituted trihydroxypiperidines.

A Review on the Tensile Properties of Bamboo Fiber Reinforced Polymer Composites

This paper reviews the tensile properties of bamboo fiber reinforced polymer composites (BFRP). Environmentally friendly bamboo fibers have good mechanical properties, which make them suitable replacements for conventional fibers, such as glass and carbon, in composite materials. Better fiber and matrix interaction results in good interfacial adhesion between fiber/matrix and fewer voids in the composite. Several important factors improve matrix-fiber bonding and enhance the tensile properties of BFRP. Coupling agents, such as maleic anhydride polypropylene (MAPP), improve the adhesion of bamboo fibers in the polypropylene (PP) matrix. A high percentage of lignin content in bamboo fibers limits fiber separation, which leads to less matrix absorption between fibers. Steam explosion is the best extraction method for bamboo fibers, although an additional mechanically rubbing process is required for fiber separation. Generally, high fiber content results in good composite performance, but at a certain limit, the matrix does not adhere well with a saturated amount of fibers, and the composite tensile strength decreases. However, the tensile modulus of BFRP is not affected by excess fiber content. Hybridization of bamboo with conventional fibers increases the tensile strength of BFRP. The addition of micro/nano-sized bamboo fibrils into the carbon fabric composites slightly enhances composite strength.

Evidence for a multivalent effect in inhibition of sulfatases involved in lysosomal storage disorders (LSDs)

New targets sensitive to multivalency: synthesis of nonavalent pyrrolidine iminosugars.

From glycals to aminosugars: a challenging test for new stereoselective aminohydroxylation and related methodologies

The most relevant methods to access 1-, 2-, 3-amino or 1,2-diaminosugars starting from unsaturated carbohydrates are concisely reviewed; the given examples illustrate the great challenges offered to several stereoselective strategies.

Management of hypothermia for perinatal asphyxia in Austria - a survey of current practice standards

BACKGROUND

Therapeutic hypothermia (HT) has been shown to reduce the risk of death or disability and increase the rate of survival free of -disability at 18-24 months of age in hypoxic-ischemic encephalopathy (HIE).

OBJECTIVES

The aim of this study was to take a national survey which (a) evaluated the practice of therapeutic HT for perinatal asphyxia in Austria, (b) evaluated the current clinical management of neonatal HIE and (c) evaluated the need for a national perinatal asphyxia and HT registry.

METHODS

In January 2013, a questionnaire was sent out to the clinical heads of all neonatal level-II and level-III units in Austria.

RESULTS

We received replies from all 30 level II and level III units in Austria (response rate 100%). 19 units (63%) answered that they applied HT, 11 units (37%) said they transferred patients for cooling to other units, 3 of those 11 units (27%) said they applied cooling during transport. 25 units (83%) felt the necessity to establish a national registry.

CONCLUSION

The results of this survey show that there is already a high implementation of therapeutic HT in Austria, but there remains a need for information, awareness and training. Problem areas tend to be in the transport of asphyxiated neonates, brain monitoring during cooling and follow-up of affected patients. We believe, that the establishment of national guidelines and a national register could increase awareness for the importance of therapeutic HT in neonatal HIE, thus improve the Austrian management of those infants.

Gold nanoparticles are suitable cores for building tunable iminosugar multivalency

Inhibition in the low micromolar range towards amyloglucosidase.

Blood transfusions using 27 gauge PICC lines: a retrospective clinical study on safety and feasibility

BACKGROUND

Blood transfusions are required by most extremely low birth weight (ELBW) infants, but sometimes an adequate peripheral venous access cannot be achieved. Under these circumstances, we used 27 Gauge (G) peripherally inserted central catheter (PICC) lines that are routinely inserted on the second day of life. Due to their narrow lumen, hemolysis of transfused erythrocytes was a major concern. We therefore performed a retrospective study in ELBW infants to analyze the incidence, safety and feasibility of PRBC transfusions via 27 G PICC lines.

METHODS

ELBW infants admitted from 08/2011-07/2012 were screened for packed red blood cell (PRBC) transfusions. Those applied via 27 G PICC lines were identified. For analysis of transfusion safety (hemolysis), hemoglobin and potassium levels as well as cardiovascular variables (invasive mean arterial blood pressure and heart rate) were evaluated before and after transfusion. For analysis of transfusion feasibility, catheter removal after transfusion and the reason for removal were recorded.

RESULTS

A total of 648 transfusions were applied in 110 ELBW infants. 27 infants (24%) received no transfusion. In 12/83 (14.5%) infants who received PRBCs, transfusions were applied using a 27 G PICC line (38/648, 5.9%). Patients who received PRBCs via the PICC line were smaller at birth (582 g [range 380-752 g] vs. 710 g [430-972 g]; 23+6 [23+1-27+6] vs. 26+0 [23+1-31+4]) and required a higher number of PRBC transfusions (n=13 vs. n=5) overall. Transfusion analysis showed an appropriate increase of blood hemoglobin levels and stable potassium levels as well as cardiovascular parameters. 4/38 of PICC lines were removed within 24 h after transfusion, one due to occlusion (15 h after transfusion).

CONCLUSIONS

We conclude that PRBC transfusions via 27 G PICC lines were feasible and performed without signs of hemolysis in ELBW infants. Our findings may help clinicians in the management of ELBW infants requiring transfusions if a peripheral venous access is not achievable.

Luminescent bi-metallic fluoroborate derivatives of bulky salen ligands

Decorating the periphery of dimeric boranils with phenyl substituents enhanced their emission efficiency, even if the substituents are not conjugated with the boron centers.

Safety of blood transfusions using 27 gauge neonatal PICC lines: an in vitro study on hemolysis

Blood transfusions are required by the majority of extremely premature infants. Packed red blood cells (PRBCs) are usually applied via simple peripheral cannulas. In situations where no peripheral venous access is achievable, 27 Gauge (G) neonatal PICC lines - that are ideally exclusively dedicated to application of parenteral nutrition - may represent a useful alternative access for PRBC transfusions. However, transfusion via small scaled catheters may damage PRBCs and lead to hemolysis. We here evaluate whether transfusion of irradiated PRBCs via 27 G PICC lines leads to hemolysis in vitro.Experimental transfusions of gamma-irradiated PRBCs were performed at increasing velocities (2.5, 3.7, 5 ml/h; full force manual push approximating 30 ml/h) via 27 G PICC lines of 20 and 30 cm length. Parameters of hemolysis (lactate dehydrogenase, potassium and free hemoglobin) were measured from the supernatants of transfused PRBCs and the percentage of hemolysis was calculated.Potassium and lactate dehydrogenase after transfusion at increasing velocities did not differ significantly from negative controls. Free hemoglobin levels showed a small but significant increase at the slowest transfusion speed (2.5 ml/h) using the 30 cm 27 G PICC line, with a relative hemolysis of only 0.13%. A manual push (approximating 30 ml/h) showed no significant changes of parameters from baseline.We conclude that transfusion of gamma-irradiated PRBCs using a 27 G neonatal PICC line does not cause clinically relevant hemolysis in vitro. Clinical studies are needed to confirm the feasibility and safety of the approach in vivo.

Endotoxin increase after fat overload is related to postprandial hypertriglyceridemia in morbidly obese patients

The low-grade inflammation observed in obesity has been associated with a high-fat diet, though this relation is not fully understood. Bacterial endotoxin, produced by gut microbiota, may be the linking factor. However, this has not been confirmed in obese patients. To study the relationship between a high-fat diet and bacterial endotoxin, we analyzed postprandial endotoxemia in morbidly obese patients after a fat overload. The endotoxin levels were determined in serum and the chylomicron fraction at baseline and 3 h after a fat overload in 40 morbidly obese patients and their levels related with the degree of insulin resistance and postprandial hypertriglyceridemia. The morbidly obese patients with the highest postprandial hypertriglyceridemia showed a significant increase in lipopolysaccharide (LPS) levels in serum and the chylomicron fraction after the fat overload. Postprandial chylomicron LPS levels correlated positively with the difference between postprandial triglycerides and baseline triglycerides. There were no significant correlations between C-reactive protein (CRP) and LPS levels. The main variables contributing to serum LPS levels after fat overload were baseline and postprandial triglyceride levels but not glucose or insulin resistance. Additionally, superoxide dismutase activity decreased significantly after the fat overload. Postprandial LPS increase after a fat overload is related to postprandial hypertriglyceridemia but not to degree of insulin resistance in morbidly obese patients.

Natural glycoconjugates with antitumor activity

Cancer is one of the major causes of death worldwide. As a consequence, many different therapeutic approaches, including the use of glycosides as anticancer agents, have been developed. Various glycosylated natural products exhibit high activity against a variety of microbes and human tumors. In this review we classify glycosides according to the nature of their aglycone (non-saccharidic) part. Among them, we describe anthracyclines, aureolic acids, enediyne antibiotics, macrolide and glycopeptides presenting different strengths and mechanisms of action against human cancers. In some cases, the glycosidic residue is crucial for their activity, such as in anthracycline, aureolic acid and enediyne antibiotics; in other cases, Nature has exploited glycosylation to improve solubility or pharmacokinetic properties, as in the glycopeptides. In this review we focus our attention on natural glycoconjugates with anticancer properties. The structure of several of the carbohydrate moieties found in these conjugates and their role are described. The structure–activity relationship of some of these compounds, together with the structural features of their interaction with the biological targets, are also reported. Taken together, all this information is useful for the design of new potential anti-tumor drugs.

[Bisphosphonate-related osteonecrosis of the jaws. An update]

Bisphosphonates are widely used drugs, primarily for osteoporosis and also in oncology. A drug-induced side effect or complication, which only recently came to light in 2003, is osteonecrosis of the jaw. This study reviews the chemical characteristics of the various bisphosphonates, their possible mechanism of action, relative potency, the commercial products available on the spanish pharmaceutical market and the indications for bisphosphonate treatment. The study also considers osteonecrosis of the jaw with regard to its onset, concept, clinical stages, why this pathology affects the jaws, its risk factors, incidence, the attitude to be adopted by dentists with patients taking bisphosphonates, a quick review of the treatment and the possible prediction of osteonecrosis.

Comparison of neonatal MRI examinations with and without an MR-compatible incubator: advantages in examination feasibility and clinical decision-making

PURPOSE

To assess the utility of an MRI-compatible incubator (INC) by comparing.

METHODS

In a retrospective study, the clinical and radiological aspects of 129 neonatal MRI examinations during a 3 year period were analyzed. Routine protocols including fast spin-echo T2-weighted (w) sequences, axial T1w, Gradient-echo, diffusion sequences, and 3D T1 gradient-echo sequences were performed routinely, angiography and spectroscopy were added in some cases. Diffusion-tensor imaging was done in 50% of the babies examined in the INC and 26% without INC. Sequences, adapted from fetal MR-protocols were done in infants younger than 32 gestational weeks. Benefit from MR-information with respect to further management was evaluated.

RESULTS

The number of the examinations increased (30-99), while the mean age (43-38, 8 weeks of gestational age) and weight (3308-2766 g) decreased significantly with the use of the MR-compatible incubator. The mean imaging time (34, 43-30, 29 min) decreased, with a mean of one additionally performed sequence in the INC group. All infants received sedatives according to our anaesthetic protocol preceding imaging, but a repeated dose was never necessary (10% without INC) using the INC. Regarding all cases, MR-based changes in clinical management were initiated in 58%, while in 57% of cases the initial ultrasound diagnosis was changed or further specified.

CONCLUSIONS

The use of the INC enables the MR access of unstable infants with suspect CNS problems to the management, of whom is improved by MR information to significantly higher percentage, than without INC.

Assessment of cellular and plasma oxidative stress in SAHS patients before and after continuous positive airway pressure treatment

BACKGROUND

Several indirect techniques have been used for measuring oxidative stress in sleep apnoea-hypopnoea syndrome (SAHS) patients. The purpose of this study was to find out if both, cellular or plasma oxidative stress evaluations, are good estimators to assess oxidative stress in SAHS patients before and after one month's CPAP treatment.

METHODS

The study included 28 SAHS patients requiring CPAP treatment and 15 healthy control subjects. Plasma and serum oxidative stress biomarkers (lipid peroxidation, total antioxidant capacity, and the activities of glutathione peroxidase, glutathione reductase, glutathione s-transferase, catalase and superoxide dismutase) were measured using commercial kits. Cellular oxidative stress biomarkers (mitochondrial membrane potential, intracellular glutathione, superoxide anion, and hydrogen peroxide) were analysed by flow cytometry. The Wilcoxon test for paired samples was used to compare oxidative stress and clinical parameters in patients before and after treatment with CPAP. Relationships in oxidative stress markers between controls and patients were analyzed using the Mann-Whitney U test. The Spearman correlation coefficient was calculated to estimate the linear correlations between variables.

RESULTS

Oxidative stress was notably decreased after CPAP. Before CPAP, SAHS severity positively correlated with hydrogen peroxide levels, while negative correlations were observed between SAHS severity and plasma TAC in patients. Also, plasma glutathione peroxidase activity negatively correlated with cellular superoxide anion, while plasma superoxide dismutase activity positively correlated with intracellular glutathione. After CPAP, plasma TAC and glutathione peroxidase activity negatively correlated with cellular hydrogen peroxide and superoxide anion.

CONCLUSIONS

In conclusion, this study seems to confirm that plasma and cellular assessment reflect, in the same way, the oxidative stress status of the studied patients. Furthermore, plasma total antioxidant capacity as well as cellular hydrogen peroxide levels can be good markers for assessing oxidative stress in SAHS patients.