Stability and Release Kinetics of an Advanced Gliclazide-Cholic Acid Formulation: The Use of Artificial-Cell Microencapsulation in Slow Release Targeted Oral Delivery of Antidiabetics

Introduction: In previous studies carried out in our laboratory, a bile acid (BA) formulation exerted a hypoglycaemic effect in a rat model of type-1 diabetes (T1D). When the antidiabetic drug gliclazide (G) was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-cholic acid (G-CA), with good structural properties, excipient compatibility and exhibits pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH-controlled properties of this new formulation. The aim is also to examine the effect of CA on G release kinetics at various pH values and different temperatures. Method: Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) and G-CA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, pH 3, pH 7.4 and pH 7.8 and temperatures of 20 and 30 °C. Results: The new formulation is further optimised by the addition of CA. CA reduced microcapsule swelling of the microcapsules at pH 7.8 and pH 3 at 30 °C and pH 3 at 20 °C, and, even though microcapsule size remains similar after CA addition, percent G release was enhanced at high pH values (pH 7.4 and pH 7.8, p < 0.01). Conclusion: The new formulation exhibits colon-targeted delivery and the addition of CA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and CA to the lower intestine

Geology, geochronology and tectonic setting of late Cenozoic volcanism along the southwestern Gulf of Mexico: The Eastern Alkaline Province revisited

A NNW-trending belt of alkaline mafic volcanic fields parallels the Gulf of Mexico from the U.S. border southward to Veracruz state, in eastern Mexico. Previous studies grouped this volcanism into the so-called “Eastern Alkaline Province” (EAP) and suggested that it resulted from Gulf-parallel extensional faulting migrating from north to south from Oligocene to Present. On the basis of new geologic studies, forty-nine unspiked K–Ar and two 40Ar–39Ar ages, we propose a new geodynamic model for the volcanism along the southwestern Gulf of Mexico. We studied in detail four of the six recognized fields of mafic alkaline volcanism in Veracruz state: 1) The lavas flows of Tlanchinol area (7.3–5.7 Ma), 2) the Alamo monogenetic field and Sierra de Tantima (7.6–6.6 Ma), 3) the Poza Rica and Metlatoyuca lava flows (1.6–1.3 Ma) and 4) the Chiconquiaco–Palma Sola area (6.9–3.2 Ma). Other two mafic volcanic fields may represent the continuation of alkaline volcanism to the southeast: the Middle Miocene lavas at Anegada High, offshore port of Veracruz, and the Middle to Late Miocene volcanism at the Los Tuxtlas. The existence of major Neogene extensional faults parallel to the Gulf of Mexico (i.e., not, vert, similarN–S to NNW–SSE) proposed in previous works was not confirmed by our geological studies. Elongation of volcanic necks, vent alignment, and faults mapped by subsurface data trend dominantly NE to ENE and NW to NNW. These directions are parallel to transform and normal faults that formed during the Late Jurassic opening of the Gulf of Mexico. Ascent of mafic magmas was likely facilitated and controlled by the existence of these pre-existing basement structures. Coupled with previous studies, our data demonstrate the occurrence of three magmatic episodes in Veracruz: 1) A Middle Miocene (not, vert, similar15–11 Ma) episode in southern Veracruz (Palma Sola, Anegada, and Los Tuxtlas); 2) A Late Miocene to Early Pliocene (not, vert, similar7.5–3 Ma) pulse of mafic alkaline volcanism throughout the study region; and 3) A Late Pliocene to Quaternary transitional to calc–alkaline volcanism in southern Veracruz (Palma Sola, Los Tuxtlas). Whereas the first and third episodes may be considered part of the subduction-related Trans-Mexican Volcanic Belt, the second pulse of mafic alkaline volcanism has a more complex origin. The absence of significant extensional faulting precludes a rift origin. We favor a model in which a transient thermal anomaly and melting of the mantle was triggered by the tearing and detachment of part of the subducted slab

Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with chitosan bioma terial preloaded with progesterone [Regeneraci�n del nervio ci�tico axotomizado del perro mediante la t�cnica de tubulizaci�n con el biomaterial quitosana precargado con progesterona]

Introduction. Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. Aims. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised-tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. Materials and methods. Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. Results. The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non-myelinated fibres were observed in all cases. Conclusions. The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve

Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with chitosan bioma terial preloaded with progesterone [Regeneración del nervio ciático axotomizado del perro mediante la técnica de tubulización con el biomaterial quitosana precargado con progesterona]

Introduction. Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. Aims. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised-tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. Materials and methods. Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. Results. The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non-myelinated fibres were observed in all cases. Conclusions. The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve

[Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with Chitosan biomaterial preloaded with progesterone]

INTRODUCTION: Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. AIMS. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. MATERIALS AND METHODS: Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. RESULTS: The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non myelinated fibres were observed in all cases. CONCLUSIONS: The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve

Bioaccumulation of selenium-by fruit origin lactic acid bacteria in tropical fermented fruit juices

Adequate fruit consumption helps to prevent several chronic age-related diseases. Selenium (Se) is an elemental micronutrient with antioxidant capacity. In general, fruits and Se ingest by humans are below the recommended daily intake value. Fresh fruits are highly susceptible to deterioration during storage. Fermentation can improve the storage period, sensory profile, and bioactive compound content of foods; moreover, some lactic acid bacteria can accumulate organic Se intracellularly. In this work, microbial growth and Se accumulation by Levilactobacillus brevis CRL2051 and Fructobacillus tropaeoli CRL2034 in tropical fruit juices were evaluated. The strains could grow 1–2 log cfu/mL, alone or combined, in mango, passion fruit, and mango/passion fruit juices, although they could not completely eliminate native microorganisms in unpasteurised juices. In pasteurised trials, both strains consumed fruit carbohydrates producing lactic acid, in addition to acetic acid, and mannitol by F. tropaeoli. Both strains accumulated Se intracellularly in the fruit juices, especially (123.0 μg/L) in the passion fruit juice fermented by the mixed culture. Finally, the Fructobacillus strain increased 3.42 times the phenolic compound concentration in the mango/passion fruit juice with added Se after 24 h. The assayed LAB strains could be used for preparing functional fermented fruit beverages bio-enriched in Se

Effect of airbrush type on sprayed platinum and platinum-cobalt catalyst inks: benchmarking as PEMFC and performance in an electrochemical hydrogen pump

Proton-exchange membrane fuel cells and electrochemical hydrogen pumps are based on membrane electrode assemblies containing Pt catalysts. During their preparation, a catalyst ink is usually applied to the gas diffusion layer. Among the available methods, ink spray using an airbrush can be advantageous for making small electrodes at universities and companies. This work compares the suitability of gravity-feed and suction-feed airbrushes during the evaluation of in-house developed Pt and Pt-Co catalysts. The surface morphology of the catalyst layers was analysed by SEM and EDS and related to the preparation technique. The catalysts were compared against an off-the-shelf catalyst. The in-house Pt catalyst afforded similar polarization curves as the commercial catalyst whereas the Pt-Co catalyst exhibited a slightly inferior performance. The suction-feed airbrush was deemed preferable because its produced cracked mud-like, homogeneous and smoother catalyst layers in contrast to the gravity-feed method, which resulted in poor-quality deposits with loose particles, lower Pt utilisation and higher resistance

Procalcitonin and C-reactive protein serum levels as markers of infection in a pediatric population with febrile neutropenia and cancer

Background: Procalcitonin and C-reactive-protein are inflammatory markers for sepsis. The authors evaluated their sensitivity and specificity in pediatric patients with cancer and febrile neutropenia. Procedure: Serum procalcitonin and C-reactive-protein were evaluated. Patients (n = 54) were divided into 2 groups, with severe infection (n = 18) or without documented infection (n = 36). Results: Procalcitonin and C-reactive protein were significantly higher in the high-risk group. Procalcitonin displayed 72.2% sensitivity and 80.5% specificity. C-reactive-protein had a sensitivity of 77.7% and specificity of 77.2%. Conclusions: Procalcitonin is an accurate predictor of bacterial infection in neutropenic children, while C-reactive-protein may be a better screening test in emergency settings. Copyright � Informa Healthcare USA, Inc

Short-Term Thermal Effect of Continuous Ultrasound from 3 MHz to 1 and 0.5 W/cm² Applied to Gastrocnemius Muscle

Continuous ultrasound is recognized for its thermal effect and use in the tissue repair process. However, there is controversy about its dosage and efficacy. This study used infrared thermography, a non-invasive technique, to measure the short-term thermal effect of 3 MHz continuous ultrasound vs. a placebo, referencing the intensity applied. It was a single-blind, randomized clinical trial of 60 healthy volunteers (19–24 years old) divided into three equal groups. Group 1:1 W/cm2 for 5 min; Group 2: 0.5 W/cm2 for 10 min; and Group 3: the placebo for 5 min. The temperature was recorded through five thermographic images per patient: pre- and post-application, 5, 10, and 15 min later. After statistical analysis, a more significant decrease in temperature (p0.05 ) was observed in the placebo group compared with the remaining groups after the application of continuous ultrasound. Group 1 was the one that generated the highest significant thermal effect (p0.001), with an increase of 3.05 °C at 15 min, compared with the other two groups. It is concluded that to generate a thermal effect in the muscle, intensities of ≥1 W/cm2 are required, since the dosage maintained a temperature increase for more than 5 min