Macrophage specific drug delivery in experimental leishmaniasis

Macrophage-specific delivery systems are the subject of much interest nowadays, because of the fact that macrophages act as host cells for many parasites and bacteria, which give rise to outbreak of so many deadly diseases(eg. leishmaniasis, tuberculosis etc.) in humans. To combat these deadly diseases initially macrophage specific liposomal delivery system were thought of and tested in vivo against experimental leishmaniasis in hamsters using a series of indigenous or synthetic antileishmanial compounds and the results were critically discussed. In vitro testing was also done against macrophages infected with Leishmania donovani, the causative agent for visceral leishmaniasis. The common problem of liposome therapy being their larger size, stability and storage, non-ionic surfactant vesicles, niosomes were prepared, for their different drug distribution and release characteristics compared to liposomes. When tested in vivo, the retention capacity of niosomes was found to be higher than that of liposomes due to the absence of lipid molecules and their smaller size. Thus the therapeutic efficacy of certain antileishmanial compounds was found to be better than that in the liposomal form. The niosomes, being cheaper, less toxic, biodegradable and non-immunogenic, were considered for sometime as suitable alternatives to liposomes as drug carriers. Besides the advent of other classical drugs carriers(e.g. neoglycoproteins), the biggest challenge came from polymeric delivery vehicles, specially the polymeric nanoparticles which were made of cost effective biodegradable polymers and different natural polymers. Because of very small size and highly stable nature, use of nanoparticles as effective drug carriers has been explored in experimental leishmaniasis using a series of antileishmanial compounds, both of indigenous and synthetic origin. The feasibility of application in vivo, when tested for biological as well as for other physicochemical parameters, the polymeric nanoparticles have turned out to be the best and thus may be projected for effective use in the clinics.     

The effect of the partially restricted sit-to-stand task on biomechanical variables in subjects with and without Parkinson’s disease

The aim of this study was to explore the electromyographic, kinetic and kinematic patterns during a partially restricted sit-to-stand task in subjects with and without Parkinson’s disease (PD). If the trunk is partially restricted, different behavior of torques and muscle activities could be found and it can serve as a reference of the deterioration in the motor performance of subjects with PD. Fifteen subjects participated in this study and electromyography (EMG) activity of the tibialis anterior (TA), soleus (SO), vastus medialis oblique (VMO), biceps femoris (BF) and erector spinae (ES) were recorded and biomechanical variables were calculated during four phases of the movement. Subjects with PD showed more flexion at the ankle, knee and hip joints and increased knee and hip joint torques in comparison to healthy subjects in the final position. However, these joint torques can be explained by the differences in kinematic data. Also, the hip, knee and ankle joint torques were not different in the acceleration phase of movement. The use of a partially restricted sit-to-stand task in PD subjects with moderate involvement leads to the generation of joint torques similar to healthy subjects. This may have important implications for rehabilitation training in PD subjects.     

Genome-scale phylogenetics: inferring the plant tree of life from 18,896 gene trees

Phylogenetic analyses using genome-scale data sets must confront incongruence among gene trees, which in plants is exacerbated by frequent gene duplications and losses. Gene tree parsimony (GTP) is a phylogenetic optimization criterion in which a species tree that minimizes the number of gene duplications induced among a set of gene trees is selected. The run time performance of previous implementations has limited its use on large-scale data sets. We used new software that incorporates recent algorithmic advances to examine the performance of GTP on a plant data set consisting of 18,896 gene trees containing 510,922 protein sequences from 136 plant taxa (giving a combined alignment length of >2.9 million characters). The relationships inferred from the GTP analysis were largely consistent with previous large-scale studies of backbone plant phylogeny and resolved some controversial nodes. The placement of taxa that were present in few gene trees generally varied the most among GTP bootstrap replicates. Excluding these taxa either before or after the GTP analysis revealed high levels of phylogenetic support across plants. The analyses supported magnoliids sister to a eudicot + monocot clade and did not support the eurosid I and II clades. This study presents a nuclear genomic perspective on the broad-scale phylogenic relationships among plants, and it demonstrates that nuclear genes with a history of duplication and loss can be phylogenetically informative for resolving the plant tree of life.     

Discovery of inhibitors of plasminogen activator inhibitor-1: structure-activity study of 5-nitro-2-phenoxybenzoic acid derivatives

Two novel series of 5-nitro-2-phenoxybenzoic acid derivatives are designed as potent PAI-1 inhibitors using hybridization and conformational restriction strategy in the tiplaxtinin and piperazine chemo types. The lead compounds 5a, 6c, and 6e exhibited potent PAI-1 inhibitory activity and favorable oral bioavailability in the rodents.     

The impact of adding trunk motion to the interpretation of the role of joint moments during normal walking

Biomechanical model assumptions affect the interpretation of the role of the muscle or joint moments to the segmental power estimated by induced acceleration analysis (IAA). We evaluated the effect of modeling the pelvis and trunk segments as two separate segments (8 SM) versus as a single segment (7 SM) on the segmental power, support of the body, knee and hip extension acceleration produced by the joint moments during the stance phase of normal walking. Significant differences were observed in the contribution of the stance hip abductor and extensor moments to support, ipsilateral knee and hip acceleration, and ipsilateral thigh and upper body power. The primary finding was that the role of the stance hip moment in generating ipsilateral thigh and upper body power differed based on degrees of freedom in the model. Secondarily, the magnitude of contributions also differed. For example, the hip abductor and extensor moments showed greater contribution to support, hip and knee acceleration in the 8 SM. IAA and segment power analysis are sensitive to the degrees of freedom between the pelvis and trunk. There is currently no gold standard by which to evaluate the accuracy of IAA predictions. However, modeling the pelvis and trunk as separate segments is closer to the anatomical architecture of the body. An 8 SM appears to be more appropriate for estimating the role of joint moments, particularly to motion of more proximal segments during normal walking.     

Design, synthesis, and biological evaluation of substituted-N-(thieno[2,3-b]pyridin-3-yl)-guanidines, N-(1H-pyrrolo[2,3-b]pyridin-3-yl)-guanidines, and N-(1H-indol-3-yl)-guanidines

Sulfonylureas stimulate insulin secretion independent of the blood glucose concentration and therefore cause hypoglycemia in type 2 diabetic patients. Over the last years, a number of aryl-imidazoline derivatives have been identified that stimulate insulin secretion in a glucose-dependent manner. In the present study, we have developed three series of substituted N-(thieno[2,3-b]pyridin-3-yl)-guanidine (2a-l), N-(1H-pyrrolo[2,3-b]pyridin-3-yl)-guanidine (3a-l), and N-(1H-indol-3-yl)-guanidine (4a-l) as new class of antidiabetic agents. In vitro glucose-dependent insulinotropic activity of test compounds 2a-l, 3a-l, and 4a-l was evaluated using RIN5F (Rat Insulinoma cell) based assay. All the test compounds showed concentration-dependent insulin secretion, only in presence of glucose load (16.7mmol). Some of the test compounds (2c, 3c, and 4c) from each series were found to be equipotent to BL 11282 (standard aryl-imidazoline), which indicated that the guanidine group acts as a bioisostere of imidazoline ring system.     

Oxidative damage of plasma proteins and lipids in epidemic dropsy patients: alterations in antioxidant status

Epidemic dropsy is an acute food adulterant disease caused due to consumption of edible mustard oil contaminated with argemone oil. Our in vitro studies have shown that the toxicity of argemone oil is due to the production of reactive oxygen species. The present study was aimed to evaluate the development of oxidative stress in terms of oxidation of plasma proteins and lipids and its correlation to enzymatic and non-enzymatic antioxidants in epidemic dropsy patients. Total plasma protein and globulin contents were found to be significantly (P<0.05) enhanced with a concomitant decrease (P<0.05) in albumin/globulin ratio in dropsy patients when compared to controls. Total cholesterol, triglycerides, low density lipoprotein cholesterol and very low density lipoprotein cholesterol were found to be significantly (P<0.05) increased with a simultaneous decrease (51%) in high density lipoprotein cholesterol in dropsy patients. The oxidation of plasma proteins and lipids were substantially enhanced (162-175%) in dropsy patients when compared to controls. Further, significant (P<0.05) decrease in superoxide dismutase, catalase, glutathione reductase and glutathione-s-transferase with a concomitant increase (69%) in glutathione peroxidase activity was noticed in dropsy patients. A significant reduction in plasma total antioxidant capacity, alpha-tocopherol, glutathione, retinol and retinyl esters content was observed in dropsy patients when compared to healthy controls. The results suggest that there exists an unproportionate equilibrium between free radicals formation and enzymatic and non-enzymatic antioxidant scavengers, which may cause oxidative damage to proteins and lipids in dropsy patients.     

Mechanism to study 1:1 stoichiometry of NADPH and alkoxyphenoxazones metabolism spectrophotometrically in subcellular biological preparations

Our prior studies have shown that pentoxyresorufin-O-dealkylation (PROD) can be measured spectrophotometrically with simultaneous monitoring of stoichiometry of NADPH/substrate and NADP/product as 10:1:10:1 [Rastogi et al. FEBS Letters 512 (2002) 121-124]. In the present investigation, mechanism of action of other enzymes in modulating the stoichiometry of alkoxyphenoxazones metabolism to 1:1 for electron donor/substrate and oxidized electron donor/product in the same incubation mixture was studied. The spectrophotometric analysis reveals 10:1 ratio between NADPH and pentoxyresorufin (PRF)-ethoxyresorufin (ERF) in microsomal system. The high ratio of electron donor to substrate is due to the presence of the other forms of P-450, which may participate in endogenous metabolism of compounds, thereby reducing the ratio to 4:1 and 7:1 for NADPH/PRF-ERF. Incubation of dicumarol in the microsomal PROD or ethoxyresorufin-O-dealkylase (EROD) assay led to significant decrease in the consumption of NADPH with a ratio of 4:1 and 7:1 for NADPH/PRF-ERF which is due to inhibition of NADPH cytochrome c (P-450) reductase. In post mitochondrial fraction (S-9), the ratio of 11:1 and 15:1 is seen for NADPH/PRF-ERF. The addition of dicumarol in S-9 fraction showed enhanced rate of alkoxyphenoxazone utilization, suggesting the possibility of reduced resorufin product as a feedback inhibitor. Equating the ratio of NADPH/substrate(s) derived after endogenous utilization of NADPH with the ratio after accounting for NADPH consumption following dicumarol addition in either S-9 or microsomal fraction, a 1:1 mol of NADPH/substrate(s) and oxidized electron donor/product is obtained. The results further suggest that cytosolic fraction may interfere in monitoring the formation of resorufin during dealkylation of alkoxyphenoxazones making dicumarol a mandatory cofactor.