Toxicological effect of endocrine disrupting insecticide (deltamethrin) on enzymatical, haematological and histopathological changes in the freshwater iridescent shark, Pangasius hypothalamus.

This study investigated the deltamethrin (DMN) induced harmful effects on Pangasius hypophthalmus using enzymatic activity, haematological, and histopathological changes. LC50 value was 0.021 mg/L at 96 h, and sublethal toxicity was tested for 45 days at two `concentrations (i.e., 1/5th and 1/10th of LC50). Haematological parameters and enzymatic activities significantly changed between DMN-exposed and control groups (p < 0.05). Histopathologically, both DMN doses induced liver hyperemia, hepatic cell rupture, necrosis, hypertrepheoid bile duct, shifting nuclei, vascular haemorrhage, and hepatocyte degeneration, while in gill, secondary lamellae destruction, a fusion of adjacent gill lamellae, hypertrophy, hyperplasia, adhesion, and fusion were noticed. Kidney developed melanomacrophages, increased periglomerular and peritubular space, vacuolation, decreased glomerulus, hyaline droplets in tubular cells, loss of tubular epithelium, distal convoluted segment hypertrophy, and granular layer in brain pyramid and Purkinje cell nucleus. But, limiting pesticide impacts on freshwater fish and their habitat requires a holistic, cradle-to-grave approach and toxicological studies.

Chronopharmacokinetic Evaluation of Budesonide Multiparticulate Systems.

BACKGROUND: Poor oral absorption of budesonide limits the design of its solid oral dosage form. With this context, multiparticulate pulsatile system of budesonide for chronotherapy of nocturnal asthma was aimed in this study. METHODS: Initially, solid dispersions of budesonide (BD) using sodium starch glycolate (SSG) and guar gum (GG) were developed and characterized. Uniform sized non-pareil seeds (~400 µm) were coated with solid dispersions to obtain immediate (BMP) and controlled release pellets by solution layering technique. Rationale of selection of BD in this research was based on recent patents such as diltiazem HCl (US5914134) and multipar-ticulate systems (US5017381). Pulsatile drug release pellets (BMPP) of BD were obtained by coating the controlled release pellets with Eudragit L100 and RS 100. Pellets were assessed by saturation sol-ubility, FTIR, DSC, micromeritic, SEM, drug content, drug release, pharmacokinetic and stability studies. RESULTS: Solubility of BD was increased by 22 folds due to inter-particle distribution of BD and polymers in solid dispersions. No changes in characteristic functional groups of BD had indicated the compatibility of drug with polymers as noticed in FTIR and DSC. Fluidized bed processor enabled the production of spherical and uniformly distributed pellets with optimum angle of repose (12-19°) and friability (<1%). Solution layering technique employed in preparation of pellets had facilitated with moderately high BD content (91.5-99.6%) and 100% drug release at the end of 12hr. The pulsatile release pellets (BMPP) produced 6hr lag phase followed by 12hr controlled release. Promised pharmacokinetics was resulted as Cmax of 380ng/ml for BMP-2 and 162ng/ml for BMPP-5 and Tmax of 5 hr for BMP-2 and 12hr for BMPP-5. Increased pharmacokinetics was the direct results of increased solubility of BD due to application of solid dispersion and solution layering on pellets. CONCLUSIONS: Chronopharmacokinetics of BD were achieved with the help of Eudragit coatings on pellets. The BMP and BMPP formulations were found to be reasonably stable over a period of time. Thus, optimal chronopharmacokinetics of BD was achieved successfully by multiparticulate pulsatile technology.

Role of proteasome-dependent protein degradation in long-term operant memory in Aplysia.

We investigated the in vivo role of protein degradation during intermediate (ITM) and long-term memory (LTM) in Aplysia using an operant learning paradigm. The proteasome inhibitor MG-132 inhibited the induction and molecular consolidation of LTM with no effect on ITM. Remarkably, maintenance of steady-state protein levels through inhibition of protein synthesis using either anisomycin or rapamycin in conjunction with proteasome inhibition permitted the formation of robust 24 h LTM. Our studies suggest a primary role for proteasomal activity in facilitation of gene transcription for LTM and raise the possibility that synaptic mechanisms are sufficient to sustain 24 h memory.

Differential role of calpain-dependent protein cleavage in intermediate and long-term operant memory in Aplysia.

In addition to protein synthesis, protein degradation or protein cleavage may be necessary for intermediate (ITM) and long-term memory (LTM) to remove molecular constraints, facilitate persistent kinase activity and modulate synaptic plasticity. Calpains, a family of conserved calcium dependent cysteine proteases, modulate synaptic function through protein cleavage. We used the marine mollusk Aplysia californica to investigate the in vivo role of calpains during intermediate and long-term operant memory formation using the learning that food is inedible (LFI) paradigm. A single LFI training session, in which the animal associates a specific netted seaweed with the failure to swallow, generates short (30min), intermediate (4-6h) and long-term (24h) memory. Using the calpain inhibitors calpeptin and MDL-28170, we found that ITM requires calpain activity for induction and consolidation similar to the previously reported requirements for persistent protein kinase C activity in intermediate-term LFI memory. The induction of LTM also required calpain activity. In contrast to ITM, calpain activity was not necessary for the molecular consolidation of LTM. Surprisingly, six hours after LFI training we found that calpain activity was necessary for LTM, although this is a time at which neither persistent PKC activity nor protein synthesis is required for the maintenance of long-term LFI memory. These results demonstrate that calpains function in multiple roles in vivo during associative memory formation.

Acute Sleep Deprivation Blocks Short- and Long-Term Operant Memory in Aplysia.

STUDY OBJECTIVES: Insufficient sleep in individuals appears increasingly common due to the demands of modern work schedules and technology use. Consequently, there is a growing need to understand the interactions between sleep deprivation and memory. The current study determined the effects of acute sleep deprivation on short and long-term associative memory using the marine mollusk Aplysia californica, a relatively simple model system well known for studies of learning and memory. METHODS: Aplysia were sleep deprived for 9 hours using context changes and tactile stimulation either prior to or after training for the operant learning paradigm, learning that food is inedible (LFI). The effects of sleep deprivation on short-term (STM) and long-term memory (LTM) were assessed. RESULTS: Acute sleep deprivation prior to LFI training impaired the induction of STM and LTM with persistent effects lasting at least 24 h. Sleep deprivation immediately after training blocked the consolidation of LTM. However, sleep deprivation following the period of molecular consolidation did not affect memory recall. Memory impairments were independent of handling-induced stress, as daytime handled control animals demonstrated no memory deficits. Additional training immediately after sleep deprivation failed to rescue the induction of memory, but additional training alleviated the persistent impairment in memory induction when training occurred 24 h following sleep deprivation. CONCLUSIONS: Acute sleep deprivation inhibited the induction and consolidation, but not the recall of memory. These behavioral studies establish Aplysia as an effective model system for studying the interactions between sleep and memory formation.

Chronic sleep deprivation differentially affects short and long-term operant memory in Aplysia.

The induction, formation and maintenance of memory represent dynamic processes modulated by multiple factors including the circadian clock and sleep. Chronic sleep restriction has become common in modern society due to occupational and social demands. Given the impact of cognitive impairments associated with sleep deprivation, there is a vital need for a simple animal model in which to study the interactions between chronic sleep deprivation and memory. We used the marine mollusk Aplysia californica, with its simple nervous system, nocturnal sleep pattern and well-characterized learning paradigms, to assess the effects of two chronic sleep restriction paradigms on short-term (STM) and long-term (LTM) associative memory. The effects of sleep deprivation on memory were evaluated using the operant learning paradigm, learning that food is inedible, in which the animal associates a specific netted seaweed with failed swallowing attempts. We found that two nights of 6h sleep deprivation occurring during the first or last half of the night inhibited both STM and LTM. Moreover, the impairment in STM persisted for more than 24h. A milder, prolonged sleep deprivation paradigm consisting of 3 consecutive nights of 4h sleep deprivation also blocked STM, but had no effect on LTM. These experiments highlight differences in the sensitivity of STM and LTM to chronic sleep deprivation. Moreover, these results establish Aplysia as a valid model for studying the interactions between chronic sleep deprivation and associative memory paving the way for future studies delineating the mechanisms through which sleep restriction affects memory formation.

Synchrony and desynchrony in circadian clocks: impacts on learning and memory.

Circadian clocks evolved under conditions of environmental variation, primarily alternating light dark cycles, to enable organisms to anticipate daily environmental events and coordinate metabolic, physiological, and behavioral activities. However, modern lifestyle and advances in technology have increased the percentage of individuals working in phases misaligned with natural circadian activity rhythms. Endogenous circadian oscillators modulate alertness, the acquisition of learning, memory formation, and the recall of memory with examples of circadian modulation of memory observed across phyla from invertebrates to humans. Cognitive performance and memory are significantly diminished when occurring out of phase with natural circadian rhythms. Disruptions in circadian regulation can lead to impairment in the formation of memories and manifestation of other cognitive deficits. This review explores the types of interactions through which the circadian clock modulates cognition, highlights recent progress in identifying mechanistic interactions between the circadian system and the processes involved in memory formation, and outlines methods used to remediate circadian perturbations and reinforce circadian adaptation.

Microemulsions based transdermal drug delivery systems.

Since the discovery of microemulsions by Jack H Schulman, there has been huge progress made in applying microemulsion systems in plethora of research and industrial process. Microemulsions are optically isotropic systems consisting of water, oil and amphiphile. These systems are beneficial due to their thermodynamic stability, optical clarity, ease of preparation, higher diffusion and absorption rates. Moreover, it has been reported that the ingredients of microemulsion can effectively overcome the diffusion barrier and penetrate through the stratum corneum of the skin. Hence it becomes promising for both transdermal and dermal drug delivery. However, low viscosity of microemulsion restrains its applicability in pharmaceutical industry. To overcome the above drawback, the low viscous microemulsions were added to viscous gel bases to potentiate its applications as topical drug delivery systems so that various drug related toxic effects and erratic drug absorption can be avoided. The present review deals with the microemulsions, various techniques involved in the development of organic nanoparticles. The review emphasized on microemulsion based systems such as hydrogels and organogels. The physicochemical characteristics, mechanical properties, rheological and stability principles involved in microemulsion based viscous gels were also explored.

Formulation and pharmacodynamic evaluation of glibenclamide incorporated niosomal gel.

OBJECTIVE: The research aims to formulate and develop the controlled release profile of glibenclamide by encapsulating glibenclamide into niosomes followed by incorporation into an aqueous gel base. MATERIALS AND METHODS: Glibenclamide incorporated niosomes were prepared by a modified ether injection technique using Span 20/Span 80 and cholesterol. The prepared niosomes were evaluated for chemical incompatibility by FT-IR, morphology, vesicle dimension, encapsulation efficiency, in-vitro diffusion and drug release kinetics. Niosomal gels were prepared by incorporating the optimized niosomes into a gel base containing Carbopol 934 and evaluated for viscosity, in-vitro diffusion and in-vivo pharmacodynamic activity. RESULTS AND DISCUSSION: The results indicated that relationship between the amount of Span and niosomal vesicular diameter was inversely proportional. Microscopic images have illustrated the sphere shape vesicles. The cumulative percentage of drug release from niosomal suspension was observed in the order GN-4>GN-2>GN- 6>GN-5>GN-3>GN-1. Glibenclamide gel showed highest percentage drug release when compared to niosomal gel. Invivo study revealed that the glibenclamide incorporated niosomal gel formulation; GNG-1 is more efficient in lowering blood glucose levels in experimental animals. CONCLUSION: The niosomal gel of glibenclamide had released the drug in well controlled manner which is supported by pharmacodynamic activity with evidence of consistent lowering of blood glucose levels.

Characterization of sleep in Aplysia californica.

STUDY OBJECTIVE: To characterize sleep in the marine mollusk, Aplysia californica. DESIGN: Animal behavior and activity were assessed using video recordings to measure activity, resting posture, resting place preference, and behavior after rest deprivation. Latencies for behavioral responses were measured for appetitive and aversive stimuli for animals in the wake and rest states. SETTING: Circadian research laboratory for Aplysia. PATIENTS OR PARTICIPANTS: A. californica from the Pacific Ocean. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Aplysia rest almost exclusively during the night in a semi-contracted body position with preferential resting locations in the upper corners of their tank. Resting animals demonstrate longer latencies in head orientation and biting in response to a seaweed stimulus and less frequent escape response steps following an aversive salt stimulus applied to the tail compared to awake animals at the same time point. Aplysia exhibit rebound rest the day following rest deprivation during the night, but not after similar handling stimulation during the day. CONCLUSIONS: Resting behavior in Aplysia fulfills all invertebrate characteristics of sleep including: (1) a specific sleep body posture, (2) preferred resting location, (3) reversible behavioral quiescence, (4) elevated arousal thresholds for sensory stimuli during sleep, and (5) compensatory sleep rebound after sleep deprivation.

Cubosomes as targeted drug delivery systems - a biopharmaceutical approach.

Cubosomes are reversed bicontinuous cubic phases and possess unique physicochemical properties. These special systems are receiving much attention for the delivery of various hydrophilic, hydrophobic and amphiphilic drugs with enhanced bioavailability and high loading capacity. A wide variety of drugs are applicable for cubosome formulation for various routes of delivery. The lipids used in cubosome formulation are more stable and offer stability to the formulation during shelf-life. The article reviews about the back ground, techniques of cubosome preparation such as high pressure homogenization, probe ultrasonication and automated cubosome preparation; and also methods of cubosomes preparation such as top down, bottom up and other methods with pictorial presentation. This article emphasizes the phase transition and also targeted approaches of cubosomes. The characterization studies for cubosomes such as cryo transmission electron microscopy, differential scanning calorimetry and scanning electron microscopy followed by in-vitro and in-vivo evaluation studies of cubosomes were explained with appropriate examples. Recent applications of cubosomes were explained with reference to flurbiprofen, odorranalectin, diazepam and dexamethasone. The advantages, disadvantages and limitations of cubosomal technology were emphasized.

Investigation of osmolyte effects on FolM: comparison with other dihydrofolate reductases.

A weak association between osmolytes and dihydrofolate (DHF) decreases the affinity of the substrate for the Escherichia coli chromosomal and R67 plasmid dihydrofolate reductase (DHFR) enzymes. To test whether the osmolyte-DHF association also interferes with binding of DHF to FolM, an E. coli enzyme that possesses weak DHFR activity, ligand binding was monitored in the presence of osmolytes. The affinity of FolM for DHF, measured by kcat/Km(DHF), was decreased by the addition of an osmolyte. Additionally, binding of the antifolate drug, methotrexate, to FolM was weakened by the addition of an osmolyte. The changes in ligand binding with water activity were unique for each osmolyte, indicating preferential interaction between the osmolyte and folate and its derivatives; however, additional evidence provided support for further interactions between FolM and osmolytes. Binding of the reduced nicotinamide adenine dinucleotide phosphate (NADPH) cofactor to FolM was monitored by isothermal titration calorimetry as a control for protein-osmolyte association. In the presence of betaine (proposed to be the osmolyte most excluded from protein surfaces), the NADPH Kd decreased, consistent with dehydration effects. However, other osmolytes did not tighten binding to the cofactor. Rather, dimethyl sulfoxide (DMSO) had no effect on the NADPH Kd, while ethylene glycol and polyethylene glycol 400 weakened cofactor binding. Differential scanning calorimetry of FolM in the presence of osmolytes showed that both DMSO and ethylene glycol decreased the stability of FolM, while betaine increased the stability of the protein. These results suggest that some osmolytes can destabilize FolM by preferentially interacting with the protein. Further, these weak attractions can impede ligand binding. These various contributions have to be considered when interpreting osmotic pressure results.

Rasmussen's encephalitis presenting as focal cortical dysplasia.

Rasmussen's encephalitis is a rare syndrome characterized by intractable seizures, often associated with epilepsia partialis continua and symptoms of progressive hemispheric dysfunction. Seizures are usually the hallmark of presentation, but antiepileptic drug treatment fails in most patients and is ineffective against epilepsia partialis continua, which often requires surgical intervention. Co-occurrence of focal cortical dysplasia has only rarely been described and may have implications regarding pathophysiology and management. We describe a rare case of dual pathology of Rasmussen's encephalitis presenting as a focal cortical dysplasia (FCD) and discuss the literature on this topic.

In-vitro assessment and pharmacodynamics of nimesulide incorporated Aloe vera transemulgel.

The aim of the investigation was to prepare nimesulide emulsion for incorporation in Aloe vera gel base to formulate 'nimesulide - Aloe vera transemulgel' (NAE) and to carryout in-vitro assessment and in-vivo anti-inflammatory studies of the product. Although the use of nimesulide is banned for oral administration, due to its potential for inducing hepatotoxicity and thrombocytopenia, the use of nimesulide for topical delivery is prominent in the treatment of many inflammatory conditions including rheumatoid arthritis. The drug loading capacity of transdermal gels is low for hydrophobic drugs such as nimesulide. Nimesulide can be effectively incorporated into emulgels (a combination of emulsion and gel). Aloe vera has a mild anti-inflammatory effect and in the present study Aloe vera gel was formulated and used as a gel base to prepare NAE. The emulgels thus prepared were evaluated for viscosity, pH, in-vitro permeation, stability and skin irritation test. In-vivo anti-inflammatory studies were performed using carrageenan induced hind paw edema method in Wistar rats. The results were compared with that of commercial nimesulide gel (CNG). From the in-vitro studies, effective permeation of nimesulide from NAE (53.04 %) was observed compared to CNG (44.72 %) at 30 min indicating better drug release from NAE. Topical application of the emulgel found no skin irritation. Stability studies proved the integrity of the formulation. The percentage of inhibition of edema was highest for the prepared NAE (67.4 % inhibition after 240 min) compared to CNG (59.6 %). From our results, it was concluded that the Aloe vera gel acts as an effective gel base to prepare nimesulide emulgel with high drug loading capacity (86.4 % drug content) compared to CNG (70.5 % drug content) with significant anti-inflammatory effect.

Estrogen modulates in vitro T cell responses in a concentration- and receptor-dependent manner: effects on intracellular molecular targets and antioxidant enzymes.

Estrogen is a key hormone in facilitating ovulation and maintenance of pregnancy in young females and subsequent decline in its production contributes to the development of age-associated disorders such as hormone-dependent cancer, osteoporosis, and cardiovascular diseases. The mechanisms through which estrogen promotes female-specific diseases with advancing age are unclear especially, its effects on immune system which is vital for the maintenance of homeostasis and health. Although the diverse effects of estrogen on Th immunity (Th1 vs. Th2) have been characterized in several cell-types and animal models, there is no direct mechanistic study to understand its immunomodulatory actions. The purpose of this study is to investigate whether the in vitro effects of 17ß-estradiol on lymphocytes from the spleen influence cell-mediated immune responses based on its concentration and type of estrogen receptors (ERs) and to assess its mechanism of action at the cellular level. Lymphocytes from the spleens of young Sprague-Dawley rats were isolated and incubated with various concentrations of 17ß-estradiol (10(-6)-10(-14)M) and specific ERα- and ß-agonists (10(-6)M, 10(-8)M and 10(-10)M) without or with concanavalin A (Con A) to measure T lymphocyte proliferation, IFN-γ and IL-2 production, p-ERK 1/2, p-CREB, and p-Akt, activities of antioxidant enzymes[superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)], and nitric oxide (NO) production. The specificity of ER-mediated actions in lymphocytes was examined by coincubation with nonspecific ER antagonists ICI(182,780) or tamoxifen. Lower concentrations of 17ß-estradiol enhanced proliferation of T lymphocytes and IFN-γ production without or with Con A stimulation but had no effect on IL-2 production. ERα and ERß agonists induced an increase in T cell proliferation and IFN-γ production and these effects were inhibited by tamoxifen. ERß agonist alone enhanced IL-2 production by the lymphocytes. Coincubation with 17ß-estradiol and ERα- and ß-agonists augmented p-ERK 1/2, p-CREB, and p-Akt expression in the lymphocytes and tamoxifen reversed the ER agonist-induced effects on these molecular targets. Estrogen increased the activities of SOD, CAT, and GPx in both non-stimulated and Con A-stimulated splenocytes in a concentration-dependent manner. Both ERα- and ß-agonists enhanced CAT and GPx activity while ERα-agonist decreased SOD activity and ERß-agonist increased SOD activity. The effects of ER agonists on the antioxidant enzymes were reversed by ICI(182,780). Coincubation of lower doses of 17ß-estradiol with Con A and both ER agonists enhanced NO production while higher dose of estrogen with Con A and ERα agonist suppressed its production and these effects were reversed by tamoxifen. Taken together, these results suggest that the effects of estrogen on the cell-mediated immune responses are dependent upon its concentrations and mediated through specific estrogen receptors involving intracellular signaling pathways and antioxidant enzymes.

Recovery of suppressed male reproduction in mice exposed to progesterone during embryonic development by testosterone.

The present study aimed to examine whether transplacental exposure to progesterone caused male reproductive abnormalities and whether the changes can be reversed after testosterone administration. Progesterone was injected to mice on day 1, 3, and 7 of pregnancy. The male pups (F1 generation) were allowed to grow for 50 days and assessed for reproductive performance. Gestational exposure to progesterone (7 mg/kg body weight) resulted in significant body weight gain with a decrease in reproductive tissue indices in mice. Total sperm count, viable sperm, and motile sperm decreased in experimental mice. Hypo-osmotic swelling test revealed that experimental mice sperm membrane integrity was severely altered. The activity levels of testicular steroidogenic marker enzymes (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B) and hydroxysteroid (17-beta) dehydrogenase 1 (HSD17B)) decreased significantly in mice exposed to progesterone during embryonic development when compared with the controls. The levels of serum testosterone decreased with an increase in serum FSH and LH in mice exposed to progesterone during embryonic development. Prenatal exposure to progesterone caused significant reduction in the number of spermatozoa and increase in the lumen of seminiferous tubule. The experimental mice that cohabited with normal females showed fertility reduction. Administration of testosterone (4.16 mg/kg body weight) on postnatal day 20, 30, and 40 to progesterone-exposed prenates resulted in recovery of progesterone-induced suppressed male reproduction. It is suggested that the impairment of male reproduction in mice exposed to progesterone during embryonic development could be mediated through the inhibition of testosterone production. These results also indicate that in utero exposure to progesterone affects male reproduction and that supplementation of testosterone restores the suppressed male reproduction.