Predictors of sustained physical activity: behaviour, bodily health, and the living environment

This study examined the determinants of sustained physical activity. Eighty-four participants undertook a 7-weeks walking regime (i.e., a 1-h biometrically-monitored walk, at least 5 days/week), with bioelectrical impedance (BIA) and total cholesterol capillary blood measurements performed before and after programme. To investigate behavioural habit formation, 7 weeks after walking termination, all participants were interviewed and (health) re-tested. Data were modelled with an artificial neural network (ANN) cascading algorithm. Our results highlight the successful prediction of continued physical activity by considering one's physical fitness state, the environmental living context, and risk for cardiovascular disease. Importantly, those artificial neural network models also taking body mass index (BMI) and blood cholesterol as predictors excel at predicting walking continuation (i.e., predictions with 93% predictability). These results are first to highlight the type and importance of available physiological drivers in maintaining a sustained physical activity regime such as walking. They are discussed within the framework of habit formation and the nowadays health and/or wellbeing focus.

Default mode function in patients with generalised epilepsy syndromes: from generalised to focal findings

INTRODUCTION

Many recent studies have suggested that generalised epilepsy is associated with cortical epileptogenic focus, and therefore distinguishing between focal and generalised often becomes difficult.

AIM OF STUDY

We aimed to detect differences between default mode function in patients with idiopathic generalised epilepsy who have discharges on EEG, and healthy persons.

MATERIAL AND METHODS

This was a case-control study; we performed EEG analysis with LORETA in 17 patients with a type of generalised epilepsy and a control group represented by 17 healthy age-matched persons. We performed statistical non- -parametric tests for current density electrical distribution for our two groups ('t-statistic on Log transformed data') and we defined regions of interest (ROIs) from the default mode network. In the second part, we compared the average activation for each ROI for each timeframe in the epoch for the group with epilepsy, and for controls (we performed a Wilcoxon rank-sum test for two means).

RESULTS

In the first part, we obtained that in the medial frontal gyrus (BA 9) delta oscillations significantly differed in patients with epilepsy who had electrical discharges on EEG in resting state conditions compared to healthy controls (medial frontal gyrus in this group had a greater number of synchronously oscillating neurons than did the controls). In the second part, we ran statistics on our localised activity from the default mode network (defined ROIs) and we obtained statistically significant differences in the left medial frontal gyrus (the values were higher for the group with epilepsy, p-value = 0.0066).

CONCLUSIONS AND CLINICAL IMPLICATIONS

It may be possible to move from a 'generalised theory' about epilepsy to a 'focused theory' by understanding how various areas of interest are activated within default mode networks. Insights into the pathophysiology of generalised epilepsy may lead to new treatment options.

Evaluation of in vitro corrosion resistance and in vivo osseointegration properties of a FeMnSiCa alloy as potential degradable implant biomaterial

In vitro electrochemical characterization and in vivo implantation in an animal model were employed to evaluate the degradation behaviour and the biological activity of FeMnSi and FeMnSiCa alloys obtained using UltraCast (Ar atmosphere) melting. Electrochemical characterization was based on open circuit potential measurement, electrochemical impedance spectroscopy and potentiodynamic polarization techniques while the alloys were immersed in Ringer's solution at 37 °C for 7 days. Higher corrosion rates were measured for the Ca-containing material, resulting from inefficient passivation of the metal surface by oxy-hydroxide products. In vivo osseointegration was investigated on a tibia implant model in rabbits by referring to a standard control (AISI 316 L) stainless steel using standard biochemical, histological and radiological methods of investigation. Changes in the biochemical parameters were related to the main stages of the bone defect repair, whereas implantation of the alloys in rabbit's tibia provided the necessary mechanical support to the injured bone area and facilitated the growth of the newly connective tissue, as well as osteoid formation and mineralization, as revealed by either histological sections or computed tomography reconstructed images and validated by the bone morphometric indices. The present study highlighted that the FeMnSiCa alloy promotes better osteoinduction and osseconduction processes when compared to the base FeMnSi alloy or with AISI 316 L, and in vivo degradation rates correlate well with corrosion resistance measurements in Ringer's solution.

Development of New Bexarotene-loaded Mesoporous Silica Systems for Topical Pharmaceutical Formulations

The present study reports the first time use of MCM-41 mesoporous silica as highly efficient carrier for bexarotene - an antineoplastic agent specific for cutaneous T-cell lymphoma treatment. Bexarotene is highly toxic and poor-water soluble, having low bioavailability in the conventional pharmaceutical forms. Comparative uptake of bexarotene on amino-functionalized silica host at various functionalization degrees is discussed in details taking into account all structural features, of matrix as well as properties of the drug molecules. The obtained results proved a successful bexarotene loading on amino-functionalized MCM-41 silica. The bexarotene molecules are adsorbed on the active centers in non-crystalline state proving the major role of the silica amino-functionalization for the drug solubility and bioavailability enhancing. In vitro dissolution tests showed a prolonged release of bexarotene during 12 h, reaching 50% release of loaded active molecules. The prolonged release has been demonstrated to be a result of the presence of aminopropyl groups on the silica pore walls.

Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

Our research has focused on in vitro and in vivo evaluations of a new Carmustine (BCNU)-loaded clinoptilolite-based delivery system. Two clinoptilolite ionic forms-hydrogen form (HCLI) and sodium form (NaCLI)-were prepared, allowing a loading degree of about 5-6 mg BCNU/g of zeolite matrix due to the dual porous feature of clinoptilolite. Clinoptilolite-based delivery systems released 35.23% of the load in 12 h for the BCNU@HCLI system and only 10.82% for the BCNU@NaCLI system. The BCNU@HCLI system was chosen to develop gel and cream semisolid dosage forms. The cream (C_BCNU@HCLI) released 29.6% of the loaded BCNU after 12 h in the Nylon synthetic membrane test and 31.6% in the collagen membrane test, higher by comparison to the gel. The new cream was evaluated in vivo in a chemically induced model of skin cancer in mice. Quantitative immunohistochemistry analysis showed stronger inhibition of B-cell lymphoma-2 (bcl-2) and cyclooxygenase 2 (cox-2) protein expression, known markers for cancer survival and aggressiveness, after the treatment with C_BCNU@HCLI by comparison to all the control treatment types, including an off-label magistral formula commercially available Carmustine cream as reference, bringing evidence that a clinoptilolite-based delivery systems could be used as a cancer drug carriers and controlled release systems (skin-targeted topical delivery systems).

Alendronate-Loaded Modified Drug Delivery Lipid Particles Intended for Improved Oral and Topical Administration

The present paper focuses on solid lipid particles (SLPs), described in the literature as the most effective lipid drug delivery systems that have been introduced in the last decades, as they actually combine the advantages of polymeric particles, hydrophilic/lipophilic emulsions and liposomes. In the current study, we present our most recent advances in the preparation of alendronate (AL)-loaded SLPs prepared by hot homogenization and ultrasonication using various ratios of a self-emulsifying lipidic mixture of Compritol 888, Gelucire 44/14, and Cremophor A 25. The prepared AL-loaded SLPs were investigated for their physicochemical, morphological and structural characteristics by dynamic light scattering, differential scanning calorimetry, thermogravimetric and powder X-ray diffraction analysis, infrared spectroscopy, optical and scanning electron microscopy. Entrapment efficacy and actual drug content were assessed by a validated HPLC method. In vitro dissolution tests performed in simulated gastro-intestinal fluids and phosphate buffer solution pH 7.4 revealed a prolonged release of AL of 70 h. Additionally, release kinetics analysis showed that both in simulated gastrointestinal fluids and in phosphate buffer solution, AL is released from SLPs based on equal ratios of lipid excipients following zero-order kinetics, which characterizes prolonged-release drug systems.

The effect of pregabalin - codeine combination on partial sciatic nerve ligation - induced peripheral mononeuropathy in rats

The present study investigates the effects of pregabalin (PGB) and codeine (COD) combination on neuropathic hyperalgesia in an animal model of peripheral nerve injury represented by partial sciatic nerve ligation. Hot plate and analgesimeter tests were performed to evaluate the influence of PGB, COD and their combination on thermal and mechanical hyperalgesia in the hind paw with partial sciatic nerve ligation. Reactivity was evaluated by measuring the latency to withdrawal of the operated hind paw from the noxious heat and pressure stimulation. Nociceptive thresholds were evaluated before (baseline) and in the 1(st), 3(rd), 5(th) and 7(th) day after surgical procedure. The investigation demonstrates that the treatment with PGB attenuated partial sciatic nerve ligation development of thermal and mechanical hyperalgesia in rats operated hind paw. The oral administration, during 14 consecutive days of PGB-COD combination significantly reduced the degree of both thermal and mechanical hyperalgesia in the hind paw with partial sciatic nerve ligation. These results suggest that the association of PGB with COD exerted ameliorative effect on partial sciatic nerve ligation-induced neuropathic pain in rats.

Effects of periodic input on the quasi-steady state assumptions for enzyme-catalysed reactions

In this paper we investigate the validity of a quasi-steady state assumption in approximating Michaelis-Menten type kinetics for enzyme-catalysed biochemical reactions that are subject to periodic substrate input.

Quasi-steady state assumptions for non-isolated enzyme-catalysed reactions

The nature and validity of the mathematical formulation of Michaelis-Menten type kinetics for enzyme-catalysed biochemical reactions is studied. Almost all previous work has concentrated on isolated reactions, i.e. those without input or other environmental influences. In this paper, we investigate the effects of substrate input on this formulation, in particular, on the nature and validity of the quasi-steady state assumptions.