Preparation and Evaluation of Miconazole Nitrate-Loaded Solid Lipid Nanoparticles for Topical Delivery

The purpose of this study was to prepare miconazole nitrate (MN) loaded solid lipid nanoparticles (MN-SLN) effective for topical delivery of miconazole nitrate. Compritol 888 ATO as lipid, propylene glycol (PG) to increase drug solubility in lipid, tween 80, and glyceryl monostearate were used as the surfactants to stabilize SLN dispersion in the SLN preparation using hot homogenization method. SLN dispersions exhibited average size between 244 and 766 nm. All the dispersions had high entrapment efficiency ranging from 80% to 100%. The MN-SLN dispersion which showed good stability for a period of 1 month was selected. This MN-SLN was characterized for particle size, entrapment efficiency, and X-ray diffraction. The penetration of miconazole nitrate from the gel formulated using selected MN-SLN dispersion as into cadaver skins was evaluated ex-vivo using franz diffusion cell. The results of differential scanning calorimetry (DSC) showed that MN was dispersed in SLN in an amorphous state. The MN-SLN formulations could significantly increase the accumulative uptake of MN in skin over the marketed gel and showed a significantly enhanced skin targeting effect. These results indicate that the studied MN-SLN formulation with skin targeting may be a promising carrier for topical delivery of miconazole nitrate.     

Dynamic ��-Helix Structure of Micelle-bound Human Amylin

Amylin is an endocrine hormone that regulates metabolism. In patients afflicted with type 2 diabetes, amylin is found in fibrillar deposits in the pancreas. Membranes are thought to facilitate the aggregation of amylin, and membrane-bound oligomers may be responsible for the islet β-cell toxicity that develops during type 2 diabetes. To better understand the structural basis for the interactions between amylin and membranes, we determined the NMR structure of human amylin bound to SDS micelles. The first four residues in the structure are constrained to form a hairpin loop by the single disulfide bond in amylin. The last nine residues near the C terminus are unfolded. The core of the structure is an α-helix that runs from about residues 5–28. A distortion or kink near residues 18–22 introduces pliancy in the angle between the N- and C-terminal segments of the α-helix. Mobility, as determined by ¹⁵N relaxation experiments, increases from the N to the C terminus and is strongly correlated with the accessibility of the polypeptide to spin probes in the solution phase. The spin probe data suggest that the segment between residues 5 and 17 is positioned within the hydrophobic lipid environment, whereas the amyloidogenic segment between residues 20 and 29 is at the interface between the lipid and solvent. This orientation may direct the aggregation of amylin on membranes, whereas coupling between the two segments may mediate the transition to a toxic structure.Type 2 diabetes affects over 100 million people worldwide (1) and is thought to cost upward of $130 billion dollars a year to treat in the United States alone (2). The endocrine hormone amylin (also known as islet amyloid polypeptide) appears to have key roles in diabetes pathology (3–5). The normal functions of amylin include the inhibition of glucagon secretion, slowing down the emptying of the stomach, and inducing a feeling of satiety through the actions of the hormone on neurons of the hypothalamus in the brain (5). The effects of amylin are exerted in concert with those of insulin and reduce the level of glucose in the blood (3, 5). Circulating amylin levels increase in a number of pathological conditions, including obesity, syndrome X, pancreatic cancer, and renal failure (3). Amylin levels together with insulin are raised initially in type 2 diabetes but fall as the disease progresses to a stage where the pancreatic islets of Langerhans β-cells that synthesize amylin no longer function (3).One of the hallmarks of type 2 diabetes, found in 90% of patients, is the formation of extracellular amyloid aggregates composed of amylin (3–5). The amyloid deposits accumulate in the interstitial fluid between islet cells and are usually juxtaposed with the β-cell membranes (3). Aggregates of amylin are toxic when added to cultures of β-cells, so that the amyloid found in situ may be responsible for β-cell death as type 2 diabetes progresses (6, 7). Genetic evidence that amylin is directly involved in pathology includes a familial S20G mutation that leads to early onset of the disease (8) and produces an amylin variant that aggregates more readily (9).As with all amyloids it is unclear whether fibrillar structures or soluble oligomers are responsible for pathology. A recurrent theme for amyloidogenic proteins is that toxicity appears to be exerted through membrane-bound oligomers that form pores and disrupt ion balance across membranes (4, 10–13). Experimental evidence for such oligomers has been found for the amyloid-β (Aβ)² peptides (14), which cause Alzheimer disease, and for α-synuclein (αS), the protein involved in Parkinson disease (15), a particular interest of our laboratory. The similar toxic effects exerted by these amyloidogenic molecules may have a common structural and physical basis. Detailed structural models are available for Aβ (16) and αS (17) bound to SDS micelle mimetics of membranes. For amylin there are models of peptide fragments 1–19 (18), 20–29 (19), and 17–29 (20) bound to micelles but as of yet no model of the complete hormone. This turns out to be particularly important as the interplay between structure and dynamics in amylin only comes to light when considering the whole molecule.Here we report the solution structure of human amylin bound to SDS micelles. We complement the structure with information on dynamics and on the immersion of amylin into micelles.     

Geriatric patient - psychological and emotional considerations during dental treatment

Objective: The world’s population is ageing rapidly with an increase in the age related diseases and disabilities. With the increase in the life span, chronic diseases play a significant role and the dental diseases are the most prevalent chronic condition. Diagnosis and treatment planning for the elderly must include considerations of the biological, psychological, social and economic status of the patient in addition to the obvious dental problems. The aim of this article is to provide a review of the psychological and emotional factors involved in the dental treatment and the methods to develop a right dental attitude. Background: Authorities in dental medicine have long recognized a relationship between psychology and dentistry and have attempted to describe the factors that require consideration during the dental therapy. The theoretical approaches are now replaced by practical approach of patient management. Materials and method: The article reviews the literature regarding the etiology for the development of psychological and emotional disturbances, factors that influence the patient’s response and methods to develop the right dental attitude. Conclusion: The dentist is concerned with the emotional and psychological state of the patient, for it is an essential component of treatment and the success of the treatment often depends on the emotional state of the patient. It is thus important for the dentist to be aware of practical‐ problem‐ oriented approach that helps in patient management and in maintaining and improving dental health as part of total healthcare services available to the elderly.     

Mesoscale Patterns in the Floristic Composition of Forests in the Central Western Ghats of Karnataka,India

We describe the mesoscale floristic patterns in the central Western Ghats of Karnataka, India, through combined analysis of woody species abundance and stand structure data from a network of ninety-six 1-ha sampling plots spread across 22,000 km². A total of 61,906 individuals (≥10 cm gbh) comprising 400 plant species from 254 genera and 75 families were recorded. Euphorbiaceae, Rubiaceae, Lauraceae and Moraceae families constituted 23.5 percent of the total number of species encountered. The relative dominance of species was skewed with Poecilonueron indicum, Xylia xylocarpa, Terminalia tomentosa and Anogeissus latifolia being dominant in some plots. Correspondence analysis (CA) and a nonmetric multidimensional scaling (NMDS) of plots by species abundances data showed similar arching patterns, with significant correlation between the first axis of CA and NMDS (r=0.77). Hierarchical clustering of plot scores along the three first CA axes resulted in splitting the plots into five different categories that broadly reflect the major bioclimatic features of the region. A multiscale bootstrapping test indicated that categorization of the wettest (wet evergreen group 1 and 2) and driest (dry deciduous) groups were robust (P<0.05 with 1000 bootstraps), while the remaining two transitional groups were uncertain (P=0.12 and 0.26 for moist deciduous and semi-evergreen group, respectively). Principal component analysis revealed that plots with similar floristic composition can encompass contrastingly different physiognomic structures (canopy cover, canopy height and mean tree diameter) probably in relation to their levels of disturbance. Observed patterns in the floristic composition have been discussed in the light of the complex interaction between the bioclimatic and disturbance regimes that characterize the region.     

Variations of two pools of glycogen and carbohydrate in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> grown with various ethanol concentrations

Glycogen, a major reservoir of energy in Saccharomyces cerevisiae, is found to be present as soluble and membrane-bound insoluble pools. Yeast cells can store excess glycogen when grown in media with higher concentration of sugar or when subjected to nutritional stress conditions. Saccharomyces cerevisiae NCIM-3300 was grown in media having ethanol concentrations up to 12% (v/v). The effects of externally added ethanol on glycogen and other carbohydrate content of yeast were studied by using alkali digestion process. Fermentative activities of cells grown in the presence of various ethanol concentrations (2–8% v/v) exhibited increase in values of glycogen and other carbohydrate, whereas cells grown with higher concentrations of ethanol (10–12% v/v) exhibited depletion in glycogen and carbohydrate content along with decrease in cell weight. Such inhibitory effect of ethanol was also exhibited in terms of reduction in total cell count of yeast grown in media with 2–16% (v/v) ethanol and 8% (w/v) sugar. These data suggest that, as the plasma membrane is a prime target for ethanol action, membrane-bound insoluble glycogen might play a protective role in combating ethanol stress. Elevated level of cell-surface α-glucans in yeast grown with ethanol, as measured by using amyloglucosidase treatment, confirms the correlation between ethanol and glycogen.     

Genomic data reveal Toxoplasma gondii differentiation mutants are also impaired with respect to switching into a novel extracellular tachyzoite state

Toxoplasma gondii pathogenesis includes the invasion of host cells by extracellular parasites, replication of intracellular tachyzoites, and differentiation to a latent bradyzoite stage. We present the analysis of seven novel T. gondii insertional mutants that do not undergo normal differentiation to bradyzoites. Microarray quantification of the variation in genome-wide RNA levels for each parasite line and times after induction allowed us to describe states in the normal differentiation process, to analyze mutant lines in the context of these states, and to identify genes that may have roles in initiating the transition from tachyzoite to bradyzoite. Gene expression patterns in wild-type parasites undergoing differentiation suggest a novel extracellular state within the tachyzoite stage. All mutant lines exhibit aberrant regulation of bradyzoite gene expression and notably some of the mutant lines appear to exhibit high proportions of the intracellular tachyzoite state regardless of whether they are intracellular or extracellular. In addition to the genes identified by the insertional mutagenesis screen, mixture model analysis allowed us to identify a small number of genes, in mutants, for which expression patterns could not be accounted for using the three parasite states--genes that may play a mechanistic role in switching from the tachyzoite to bradyzoite stage.     

The effect of dietary carbohydrate on the rise in plasma glutamate concentrations following oral glutamate ingestion in rats

Plasma glutamate concentrations were examined in male rats following oral intubation of monosodium L-glutamic acid (MSG, 250 mg/kg) soon after ingesting one of several meals differing in carbohydrate content. Intubation of MSG alone produced a 4-fold rise in plasma glutamate that peaked at 15 min, and returned to baseline by 60 min. Red blood cell glutamate concentrations were unchanged. The ingestion of a meal lacking carbohydrate produced a modest attenuation of the post-MSG intubation rise in plasma glutamate concentrations. This attenuating effect increased progressively with the carbohydrate content of the meal (and as the protein content declined, to maintain isocaloric meals), though as little as 5% carbohydrate marked attenuated the plasma glutamate rise. This effect diminished as the time interval between the meal and MSG intubation increased from 1 to 4 hrs. Similar, but not identical effects were noted when meals substituted fat (instead of protein) for carbohydrate. The intubation of MSG alone produced a slight increase in plasma alanine concentrations over the 60-min post-intubation period examined. The ingestion of any of the meals just prior to intubation did not influence this effect. Overall, the results indicate that although the ingestion of carbohydrate can markedly attenuate the rise in plasma glutamate that follows MSG consumption in rats, this effect is also influenced by the other macronutrients present. The absence of notable, meal related changes in plasma alanine suggests that this parameter does not provide a useful indication of gut glutamate transamination.     

Role of C-reactive protein in complement-mediated hemolysis in Malaria

Human C-reactive protein (CRP) is a clinically important classical acute phase protein. Although CRP has been reported to bind with many nucleated cells, the direct binding of CRP to erythrocytes in diseases remains largely unexplored. The main focus of the present study was to investigate the binding of disease-specific CRP to erythrocytes of same patients. Distinct molecular variant of disease-specific CRP was affinity purified from sera of malaria patients (CRP_Mal). This CRP showed strong binding with malaria erythrocytes (RBC_Mal) as confirmed by flow cytometric analysis (FACS), enzyme-linked immunosorbent assays (ELISA), and radio binding assays. Calcium and phosphoryl choline (PC) were found to be essential for this interaction. A 2.3-fold increased binding of induced CRP to RBC_Mal as compared to normal erythrocytes (RBC_N) confirmed disease-specificity. Preincubation of RBC_Mal with unconjugated CRP showed 3–5 fold inhibition. The association constant of CRP and RBC_Mal was 4.7 × 10⁶ cpm/μg with the corresponding number of receptors/cell being 4.3 × 10⁵. The effector function of CRP_Mal has been demonstrated by its potency to activate the complement pathway. An optimal dose of 10 μg/ml of CRP induced three-fold higher hemolysis of patient erythrocytes as compared to RBC_N. These studies provide direct evidence for an important phagocytic functional interaction of this acute-phase protein by triggering the CRP-complement pathway after the binding of CRP_Mal with RBC_Mal. Hemolysis as triggered by this pathway may be one of the causative factors of anemia, a common clinical manifestation of this disease.