Liposomes encapsulating polymeric chitosan based vesicles - a vesicle in vesicle system for drug delivery

Drug delivery systems comprising vesicles prepared from one amphiphile encapsulating vesicles prepared from a second amphiphile have not been prepared previously due to a tendency of the bilayer components of the different vesicles to mix during preparation. Recently we have developed polymeric vesicles using the new polymer-palmitoyl glycol chitosan and cholesterol in a 2:1 weight ratio. These polymeric vesicles have now been encapsulated within egg phosphatidylcholine (egg PC), cholesterol (2:1 weight ratio) liposomes yielding a vesicle in vesicle system. The vesicle in vesicle system was visualised by freeze fracture electron microscopy. The mixing of the different bilayer components was studied by monitoring the excimer fluorescence of pyrene-labelled polymeric vesicles after their encapsulation within egg PC liposomes or hexadecyl diglycerol ether niosomes. A minimum degree of lipid mixing was observed with the polymeric vesicle-egg PC liposome system when compared to the polymeric vesicle-hexadecyl diglycerol ether niosome system. The polymeric vesicle-egg PC vesicle in vesicle system was shown to retard the release of encapsulated solutes. 28% of 5(6)-carboxyfluorescein (CF) encapsulated in the polymeric vesicle compartment of the vesicle in vesicle system was released after 4 h compared to the release of 62% of encapsulated CF from plain polymeric vesicles within the same time period

Dendrimers in gene delivery

Dendrimers have unique molecular architectures and properties that make them attractive materials for the development of nanomedicines. Key properties such as defined architecture and a high ratio of multivalent surface moieties to molecular volume also make these nanoscaled materials highly interesting for the development of synthetic (non-viral) vectors for therapeutic nucleic acids. Rational development of such vectors requires the link to be made between dendrimer structure and the morphology and physicochemistry of the respective nucleic acid complexes and, furthermore, to the biological performance of these systems at the cellular and systemic level. The review focuses on the current understanding of the role of dendrimers in those aspects of synthetic vector development. Dendrimer-based transfection agents have become routine tools for many molecular and cell biologists but therapeutic delivery of nucleic acids remains a challenge

FUNGAL CONTAMINANTS ASSOCIATED WITH SOME FOOD STUFF IN OWERRI, SOUTHEAST, NIGERIA

This study aimed at isolating and identifying fungal contaminants of some selected food items (rice, maize, beans, groundnut, and peanut) in Owerri, Imo State Nigeria. An oral ethical approval was obtained from the Market Master before sample collection. Different fungal contaminants were isolated from all the selected raw and boiled food items that were directly seeded unto Sabouraud Dextrose Agar (SDA) supplemented with chloramphenicol, incubated at room temperature for 7 days, and were checked for growth daily. From the results obtained, a total of six (6) fungi were isolated and identified from all the samples cultured. The total of each mycotoxin-producing fungi isolated is Aspergillus spp. 8 (29.6%), Penicillium spp. 5 (18.5%), Mucor spp. 5 (18.5%), Rhizopus spp. 5 (18.5%), Geotrichum spp. 3 (11.1%) and Botrytis spp.1 (3.7%). Out of all the fungal isolates, a frequency of 3.3 (55.6%) was identified from the raw food samples and 2.7 (44.4%) from the boiled samples. The slight dissimilarity seen between the raw and boiled food fungal isolates is a result of the denaturation of the nutrient value of the grains during boiling and the ability of the fungal spores (that are thermoduric and heat-stable) to form a biofilm that can resist deactivation

Properties of Soils and Plants Uptake within the Vicinity of Selected Automobile Workshops in Ile-Ife Southwestern, Nigeria

Backyard farming is becoming popular among the auto mechanics near their workshops where spent engine oil and carcass of vehicles are continuously dumped in Nigeria. The properties of soil and maize plants sampled from the vicinity of selected auto mechanic workshops in Ile-Ife, Nigeria were investigated. The results showed that heavy metal contents in the soils from the sampled sites were (range, mg kg-1) Fe 1238.12 to 1564.25, Zn 18.10 to 24.75, Pb 1.21 to 3.43 and Hg 0.48 to 0.74. These values were significantly (P< 0.05) higher than the control (non auto mechanic site) with Fe 37.50, Zn 0.70, Pb 0.15 and Hg 0.13 mg kg-1. Also, these soil parameters reduced in values in the sub-soil. The mean concentrations of heavy metals (Fe, Zn, Pb and Hg) in maize plants were significantly (P < 0.05) higher while N and P were significantly (P < 0.05) lower in those from the experimental sites within the vicinity of automobile workshops than in the control. Higher accumulation of these heavy metals was obtained in soil and shoots of maize from older workshops than in the younger ones. The study therefore concluded that edible crops, particularly the phytoplants should not be cultivated on polluted soils as this may pose a threat to human health, if the heavy metals enter the food chain.Keywords: Backyard farming, automobile, spent engine oil, carcass of vehicle, plant uptake, phytoplant

An Evaluation of the Phytochemical and Nutrient Composition of the Seeds and Stem Bark of Detarium senegalense Gmelin

The chemical constituents of the seeds and stem bark of Detarium senegalense Gmelin used as soup thickener and in herbal medicine in south Eastern Nigeria were studied. Phytochemical studies revealed the presence of alkaloids (0.37% - 0.72%), flavonoids (2.28% - 5.68%), tannins (0.47% - 0.79%), phenols (0.35% - 0.67%) and saponins (1.85% - 4.60%). The mineral constituents were Ca (1.44% - 1.80%), Mg (0.32% - 0.40%), K (0.50% - 0.85%), Na (0.53% - 0.40%), P (1.00% - 0.54%), Fe (7.11% - 6.97%), Mn (0.45% - 0.70%), and Zn (5.40% - 6.15%). The plant samples were found to be rich in vitamins comprising riboflavin (0.62mg/100g – 0.60mg/100g), thiamin (0.14mg/100g – 0.27mg/100), niacin (2.06mg/100g – 8.11mg/100g)and ascorbic acid (83.6mg/100 – 24.2mg/100g). The proximate composition   revealed the presence of   protein (20.5% - 9.60%), crude fibre (10.5% - 17.8%), fats/oil (55.6% - 3.56%), ash (5.00% - s5.50%), carbohydrates (8.40% - 63.54%) and food energy (616.0g/cal – 324.6g/cal.). Keywords: Chemical composition, leguminosae, saponins , tannins, flavonoids

Anticancer drug delivery with transferrin targeted polymeric chitosan vesicles

The study reports the initial biological evaluation of targeted polymeric glycol chitosan vesicles as carrier systems for doxorubicin (Dox). Transferrin (Tf) was covalently bound to the Dox-loaded palmitoylated glycol chitosan (GCP) vesicles using dimethylsuberimidate (DMSI). For comparison, glucose targeted niosomes were prepared using N-palmitoyl glucosamine. Biological properties were studied using confocal microscopy, flow cytometry, and cytotoxicity assays as well as a mouse xenograft model. Tf vesicles were taken up rapidly with a plateau after 1-2 h and Dox reached the nucleus after 60-90 min. Uptake was not increased with the use of glucose ligands, but higher uptake and increased cytotoxicity were observed for Tf targeted as compared to GCP Dox alone. In the drug-resistant A2780AD cells and in A431 cells, the relative increase in activity was significantly higher for the Tf-GCP vesicles than would have been expected from the uptake studies. All vesicle formulations had a superior in vivo safety profile compared to the free drug. The in vitro advantage of targeted Tf vesicles did not translate into a therapeutic advantage in vivo. All vesicles reduced tumor size on day 2 but were overall less active than the free drug

Ultrasmall-in-Nano: Why Size Matters

Gold nanoparticles (AuNPs) are continuing to gain popularity in the field of nanotechnology. New methods are continuously being developed to tune the particles’ physicochemical properties, resulting in control over their biological fate and applicability to in vivo diagnostics and therapy. This review focuses on the effects of varying particle size on optical properties, opsonization, cellular internalization, renal clearance, biodistribution, tumor accumulation, and toxicity. We review the common methods of synthesizing ultrasmall AuNPs, as well as the emerging constructs termed ultrasmall-in-nano—an approach which promises to provide the desirable properties from both ends of the AuNP size range. We review the various applications and outcomes of ultrasmall-in-nano constructs in vitro and in vivo

Preschool Teacher Perspectives on Challenging Behavior and Behavior Management in Teacher-Student Relationships

Abstract Challenging behavior is an expected part of development among preschool children, but persistent disruptive behaviors can lead to teacher stress and burnout and negative student-teacher relationships. Challenging behaviors are disruptive behaviors that interfere with teaching and learning and can sometimes threaten the safety of children and teachers in the classroom. According to current research, students’ academic success is contingent on the nature of the relationships they have with their teachers. The purpose of this basic qualitative study was to explore preschool teachers’ perspectives regarding challenging behaviors and how the strategies they use to manage such behaviors could affect relationships with students who exhibit challenging behaviors. Research questions focused on teacher description of how challenging behavior and their response to this behavior affects their relationship with the child. Lazarus and Folkman’s transactional model of stress and coping served as this study’s conceptual framework for this study. Data for this study were gathered from 10 Head Start teachers who were interviewed using the think-aloud interview method applied to scenarios depicting challenging behavior that were drawn from actual events. Thematic coding was applied to the resulting data to answer the study’s research questions. Study findings showed that most teachers believed challenging behaviors and behavior management do not affect their teacher-student relationships, but some teachers felt threatened by children who exhibit challenging behavior. The findings of this study may support the inclusive perspective of Head Start teachers in response to challenging behaviors and may lead to increased support for teachers and the children they serve

Niosomes and polymeric chitosan based vesicles bearing transferrin and glucose ligands for drug targeting

PURPOSE: To prepare polymeric vesicles and niosomes bearing glucose or transferrin ligands for drug targeting. METHODS: A glucose-palmitoyl glycol chitosan (PGC) conjugate was synthesised and glucose-PGC polymeric vesicles prepared by sonication of glucose-PGC/cholesterol. N-palmitoylglucosamine (NPG) was synthesised and NPG niosomes also prepared by sonication of NPG/ sorbitan monostearate/ cholesterol/ cholesteryl poly-24-oxyethylene ether. These 2 glucose vesicles were incubated with colloidal concanavalin A gold (Con-A gold), washed and visualised by transmission electron microscopy (TEM). Transferrin was also conjugated to the surface of PGC vesicles and the uptake of these vesicles investigated in the A431 cell line (over expressing the transferrin receptor) by fluorescent activated cell sorter analysis. RESULTS: TEM imaging confirmed the presence of glucose units on the surface of PGC polymeric vesicles and NPG niosomes. Transferrin was coupled to PGC vesicles at a level of 0.60+/-0.18 g of transferrin per g polymer. The proportion of FITC-dextran positive A431 cells was 42% (FITC-dextran solution), 74% (plain vesicles) and 90% (transferrin vesicles). CONCLUSIONS: Glucose and transferrin bearing chitosan based vesicles and glucose niosomes have been prepared. Glucose bearing vesicles bind Con-A to their surface. Chitosan based vesicles are taken up by A431 cells and transferrin enhances this uptake