Development and evaluation of novel in situ depot-forming controlled release formulations

Title from PDF of title page, viewed on October 24, 2011Dissertation advisor: Ashim K. MitraVitaIncludes bibliographical references (p. 164-176)Thesis (Ph.D.)--School of Pharmacy and Dept. of Chemistry. University of Missouri--Kansas City, 2011Controlled drug delivery utilizing novel biodegradable and biocompatible pentablock copolymers could be a valuable strategy for the treatment of chronic eye diseases. In attempts to achieve controlled drug release, various approaches were evaluated which eventually resulted in the development of novel polymeric material and a delivery system. Poly (ethylene glycol)-poly (ε-caprolactone)-poly (ethylene glycol) (PEG-PCL-PEG) thermosensitive hydrogel was employed for sustained drug delivery. A polymeric additives strategy was selected based on the property to provide better packing through intra- and intermolecular interactions between the triblock polymeric chains of the hydrogel matrix. PCL was selected as a hydrophobic additive and polyvinyl alcohol (PVA) as a hydrophilic additive, respectively. The additives strategy was found to modulate the sol-gel transition and drug release kinetics from the hydrogel. The effect of PCL on the sol-gel transition was more pronounced than PVA. However, PVA played a dominant role in regulating drug release kinetics, whereas no significant difference in drug release was observed with PCL. To accelerate the degradation rate of highly crystalline and hydrophobic PCL block we have successfully synthesized pentablock polymers based thermosensitive hydrogel by incorporating PLA block in the center of PEG-PCL-PEG. These polymers were characterized by 1H NMR, GPC, and FT-IR. The effect of block composition on the sol-gel transition, crystallinity, and drug release kinetics was studied. The release kinetics of hydrophobic drug was easily modulated by altering the hydrophobic block segment. Moreover, the effect of block composition on the sol-gel transition was evaluated. A specific combination of molecular weight and block ratio of pentablock copolymer can be utilized for nanoparticles preparation. We have also successfully polymerized PCL with PEG and faster degrading blocks such as polyglycolic acid and and polylactic acid for the preparation of nanoparticles. Nanoparticles alone demonstrate initial burst release due to surface adsorbed drug molecule. A final composite formulation based approach (nanoparticles suspended in thermosensitive gel) minimized the burst release of drug and resulted in continuous nearly zero order drug release. Pentablock copolymers also resulted in a negligible release of inflammatory mediators in different cell lines. Therefore, we have successfully developed a novel biomaterial for controlled drug delivery.Literature review -- Introduction -- Effect of hydrophobic and hydrophilic additives on sol-gel transition and release behavior of timolol maleate from polycaprolactone based hydrogels -- Synthesis and characterization of novel thermosensitive pentablock hydrogels for controlled drug delivery -- Synthesis and characterization of different pentablock copolymer compositions in the preparation of nanoparticles -- Evaluation of different pentablock copolymer compositions biocompatibility utilizing various cell lines -- Development and evaluation of composite formulations of nanoparticles suspended in thermosensitive hydroges -- Summary and recommendation

Sixth cervical vertebra with bilateral double foramen transversarium and non-bifid spine: a rare case

Anatomical knowledge of variations is of utmost clinical importance to all of us as they may be one of the reasons as etiological as well as of surgical importance. Vertebral region also presents many variations. Foramen transversarium are typical feature of cervical vertebrae and give way to neurovascular bundle, like vertebral artery, vertebral veins and sympathetic plexus around them throughout. Foramen transversarium and spine or spinous process of cervical vertebrae are important to all of medical specialists as well as for surgeons specially the surgeons dealing with head & neck surgeries. Knowledge of anatomical/surgical variations is very important for neurosurgeons and radiologists for reporting and planning for surgeries as this type of variation if ignored may be a cause for fatal or undesirable outcome of the surgical procedure or may lead to a different planning/approach at the time or during the surgical procedure. In the present case we observed very uncommon finding of bilateral double foramen transversarium as well as a nonbifid spinous process in sixth cervical vertebra which is extremely rare. Right and left both main foramen transversarium were bilateral symmetrical and rounded in shape. Right accessory foramen transversarium was complete while left was incomplete. Finding of present study is important in neurosurgery for posterior approaches of the cervical vertebrae and also useful for radiological studies to avoid erroneous counting of cervical spines in clinical observations as surface landmark

Cracking of enigma of Evans: a rare association with Sjogren and systemic lupus erythematosus

Evans syndrome (ES) is characterized by the simultaneous or consecutive occurrence of warm autoimmune hemolytic anemia (AIHA) along with immune thrombocytopenia (ITP), and less commonly, autoimmune neutropenia. It may manifest spontaneously or as a result of autoimmune, malignancy or lymphoproliferative disease. Clinical manifestations may be associated with hemolysis and thrombocytopenia, potentially leading to life-threatening outcomes. ES is a rare diagnosis of exclusion. Due to its infrequency, the treatment is typically empirical, relying largely on intravenous corticosteroids or immunoglobulins. We are presenting case of a 46-year-old- female with bleeding from the mouth and gums and rashes all over the body with no prior diagnosis of rheumatological disorder. This case is pivotal as it highlights a key factor contributing to ES and presents a pragmatic method for addressing the condition

Overexpression of Bacterial mtlD

In the changing global environmental scenarios, water scarcity and recurrent drought impose huge reductions to the peanut (Arachis hypogaea L.) crop yield. In plants, osmotic adjustments associated with efficient free radical scavenging ability during abiotic stress are important components of stress tolerance mechanisms. Mannitol, a compatible solute, is known to scavenge hydroxyl radicals generated during various abiotic stresses, thereby conferring tolerance to water-deficit stress in many plant species. However, peanut plant is not known to synthesize mannitol. Therefore, bacterial mtlD gene coding for mannitol 1-phosphate dehydrogenase under the control of constitutive promoter CaMV35S was introduced and overexpressed in the peanut cv. GG 20 using Agrobacterium tumefaciens-mediated transformation. A total of eight independent transgenic events were confirmed at molecular level by PCR, Southern blotting, and RT-PCR. Transgenic lines had increased amount of mannitol and exhibited enhanced tolerance in response to water-deficit stress. Improved performance of the mtlD transgenics was indicated by excised-leaf water loss assay and relative water content under water-deficit stress. Better performance of transgenics was due to the ability of the plants to synthesize mannitol. However, regulation of mtlD gene expression in transgenic plants remains to be elucidated

Auto-antibodies targeting brain antigens in Plasmodium falciparum infected patients as biomarkers of Cerebral Malaria

International audiencen.

Evaluation and Multivariate Analysis of Cowpea [Vigna unguiculata (L.) Walp] Germplasm for Selected Nutrients—Mining for Nutri-Dense Accessions

A total of 120 highly diverse cowpea [Vigna unguiculata (L.) Walp] genotypes, including indigenous and exotic lines, were evaluated for different biochemical traits using AOAC official methods of analysis and other standard methods. The results exhibited wide variability in the content of proteins (ranging from 19.4 to 27.9%), starch (from 27.5 to 42.7 g 100 g−1), amylose (from 9.65 to 21.7 g 100 g−1), TDF (from 13.7 to 21.1 g 100 g−1), and TSS (from 1.30 to 8.73 g 100 g−1). The concentration of anti-nutritional compounds like phenols and phytic acid ranged from 0.026 to 0.832 g 100 g−1 and 0.690 to 1.88 g 100 g−1, respectively. The correlation coefficient between the traits was calculated to understand the inter-trait relationship. Multivariate analysis (PCA and HCA) was performed to identify the major traits contributing to variability and group accessions with a similar profile. The first three principal components, i.e., PC1, PC2, and PC3, contributed to 62.7% of the variation, where maximum loadings were from starch, followed by protein, phytic acid, and dietary fiber. HCA formed six distinct clusters at a squared Euclidean distance of 5. Accessions in cluster I had high TDF and low TSS content, while cluster II was characterized by low amylose content. Accessions in cluster III had high starch, low protein, and phytic acid, whereas accessions in cluster IV contained high TSS, phenol, and low phytic acid. Cluster V was characterized by high protein, phytic acid, TSS, and phenol content and low starch content, and cluster VI had a high amount of amylose and low phenol content. Some nutri-dense accessions were identified from the above-mentioned clusters, such as EC169879 and IC201086 with high protein (>27%), TSS, amylose, and TDF content. These compositions are promising to provide practical support for developing high-value food and feed varieties using effective breeding strategies with a higher economic value

Genome-wide association studies for phenological and agronomic traits in mungbean (Vigna radiata L. Wilczek)

Mungbean (Vigna radiata L. Wilczek) is one of the important warm-season food legumes, contributing substantially to nutritional security and environmental sustainability. The genetic complexity of yield-associated agronomic traits in mungbean is not well understood. To dissect the genetic basis of phenological and agronomic traits, we evaluated 153 diverse mungbean genotypes for two phenological (days to heading and days to maturity) and eight agronomic traits (leaf nitrogen status using SPAD, plant height, number of primary branches, pod length, number of pods per plant, seeds per pod, 100-seed weight, and yield per plant) under two environmental conditions. A wide array of phenotypic variability was apparent among the studied genotypes for all the studied traits. The broad sense of heritability of traits ranged from 0.31 to 0.95 and 0.21 to 0.94 at the Delhi and Ludhiana locations, respectively. A total of 55,634 genome-wide single nucleotide polymorphisms (SNPs) were obtained by the genotyping-by-sequencing method, of which 15,926 SNPs were retained for genome-wide association studies (GWAS). GWAS with Bayesian information and linkage-disequilibrium iteratively nested keyway (BLINK) model identified 50 SNPs significantly associated with phenological and agronomic traits. In total, 12 SNPs were found to be significantly associated with phenological traits across environments, explaining 7%–18.5% of phenotypic variability, and 38 SNPs were significantly associated with agronomic traits, explaining 4.7%–27.6% of the phenotypic variability. The maximum number of SNPs (15) were located on chromosome 1, followed by seven SNPs each on chromosomes 2 and 8. The BLAST search identified 19 putative candidate genes that were involved in light signaling, nitrogen responses, phosphorus (P) transport and remobilization, photosynthesis, respiration, metabolic pathways, and regulating growth and development. Digital expression analysis of 19 genes revealed significantly higher expression of 12 genes, viz. VRADI01G08170, VRADI11G09170, VRADI02G00450, VRADI01G00700, VRADI07G14240, VRADI03G06030, VRADI02G14230, VRADI08G01540, VRADI09G02590, VRADI08G00110, VRADI02G14240, and VRADI02G00430 in the roots, cotyledons, seeds, leaves, shoot apical meristems, and flowers. The identified SNPs and putative candidate genes provide valuable genetic information for fostering genomic studies and marker-assisted breeding programs that improve yield and agronomic traits in mungbean

Development and optimization of NIRS prediction models for simultaneous multi-trait assessment in diverse cowpea germplasm

Cowpea (Vigna unguiculata (L.) Walp.) is one such legume that can facilitate achieving sustainable nutrition and climate change goals. Assessing nutritional traits conventionally can be laborious and time-consuming. NIRS is a technique used to rapidly determine biochemical parameters for large germplasm. NIRS prediction models were developed to assess protein, starch, TDF, phenols, and phytic acid based on MPLS regression. Higher RSQexternal values such as 0.903, 0.997, 0.901, 0.706, and 0.955 were obtained for protein, starch, TDF, phenols, and phytic acid respectively. Models for all the traits displayed RPD values of >2.5 except phenols and low SEP indicating the excellent prediction of models. For all the traits worked, p-value ≥ 0.05 implied the accuracy and reliability score >0.8 (except phenol) ensured the applicability of the models. These prediction models will facilitate high throughput screening of large cowpea germplasm in a non-destructive way and the selection of desirable chemotypes in any genetic background with huge application in cowpea crop improvement programs across the world

Heat stress tolerance in peas (Pisum sativum L.): Current status and way forward

In the era of climate change, the overall productivity of pea (Pisum sativum L.) is being threatened by several abiotic stresses including heat stress (HS). HS causes severe yield losses by adversely affecting several traits in peas. A reduction in pod yield has been reported from 11.1% to 17.5% when mean daily temperature increase from 1.4 to 2.2°C. High-temperature stress (30.5-33°C) especially during reproductive phase is known to drastically reduce both seed yield and germination. HS during germination and early vegetative stage resulted in poor emergence and stunted plant growth along with detrimental effects on physiological functions of the pea plant. To combat HS and continue its life cycle, plants use various defense strategies including heat escape, avoidance or tolerance mechanisms. Ironically, the threshold temperatures for pea plant and its responses are inconsistent and not yet clearly identified. Trait discovery through traditional breeding such as semi leaflessness (afila), upright growing habit, lodging tolerance, lower canopy temperature and small seeded nature has highlighted their utility for greater adaptation under HS in pea. Screening of crop gene pool and landraces for HS tolerance in a targeted environment is a simple approach to identify HS tolerant genotypes. Thus, precise phenotyping using modern phenomics tools could lead to increased breeding efficiency. The NGS (next generation sequencing) data can be associated to find the candidate genes responsible for the HS tolerance in pea. In addition, genomic selection, genome wide association studies (GWAS) and marker assisted selection (MAS) can be used for the development of HS tolerant pea genotypes. Additionally, development of transgenics could be an alternative strategy for the development of HS tolerant pea genotypes. This review comprehensively covers the various aspects of HS tolerance mechanisms in the pea plant, screening protocols, omic advances, and future challenges for the development of HS tolerant genotypes