Preparation, Characterization and Dissolution Behaviour of Freeze Dried Complexes of Curcumin-Gamma Cyclodextrin

The aim of the current research was to develop and characterize curcumin-gamma cyclodextrin inclusion complexes in order to enhance solubility and rate of dissolution of poorly soluble curcumin. Based on the stoichiometric ratio of 1:1, the inclusion complexes of curcumin with γ-cyclodextrin were prepared by freeze drying method. The prepared dried and solidified inclusion complexes were characterized with the help of infrared spectroscopy, differential scanning calorimetry, and X-ray diffractometry. The comparative evaluation of solubility and rate of dissolution were investigated and compared with pure curcumin. Dissolution study demonstrated only 10% release from pure curcumin at 1 hour as opposed of approximately 72% release form freeze dried curcumin complexes. The freeze dried complexes exhibited almost complete release after 5 hours while only 34% release was observed from the pure curcumin during the same time period. Therefore, the freeze dried complex provided approximately 3 to 7-fold enhancement in the dissolution and release of curcumin over a period of 6 hours of dissolution testing.  The kinetics of the in vitro release behaviors of the curcumin and curcumin complexes were investigated by applying various models such as zero order, first order, Higuchi and Peppas models. The release of the curcumin was observed to follow the first order release kinetics, since the correlation coefficient (R2) for the first order was the highest in comparison to other kinetic models.

A bioimpedance analysis of head-and-neck cancer patients undergoing radiotherapy

Malnutrition is a frequent manifestation in patients with head-and-neck cancer undergoing radiation therapy and a major contributor to morbidity and mortality. Thus, body composition is an important component of an overall evaluation of nutrition in cancer patients. Malnutrition is characterized by weight loss, loss of muscle mass, changes in cell membrane integrity, and alterations in fluid balance. Bioelectrical impedance analysis is a method to analyze body composition and includes parameters such as intracellular water content, extracellular water content, and cell membrane integrity in the form of a phase angle (Φ). Bioelectrical impedance analysis has consistently been shown to have prognostic value with respect to mortality and morbidity in patients undergoing chemotherapy. The goal of the present study was to evaluate the relationship between Φ, time, intracellular water content, and weight for head-and-neck cancer patients undergoing radiotherapy. The results demonstrate that Φ decreases with time and increases with intracellular water content and weight.

Formulation development of novel in situ nanoemulgel (NEG) of ketoprofen for the treatment of periodontitis

The aim of the present study was to formulate and evaluate in situ gelling syringeable nanoemulgels (NEGs) of ketoprofen for periodontal delivery. Application of 3-factor 3-level design was employed using the Box-Behnken experimental design for the optimization of nanoemulsion using three independent variables such as percent concentration (v/v) of oil (X1), S mix (mixture of surfactant and cosurfactant) (X2) and water (X3); while the particle size (nm) (Y1), polydispersity index (Y2) and zeta potential (mV) (Y3) were used as dependent variables. The NEG was evaluated based on their drug content, pH measurement, mucoadhesion on the goat buccal mucosa, syringeability and inverted sol-gel transition temperature. The drug release data were analyzed for curve fitting based on the Korsmeyer-Peppas law, and the n-values of optimized A5 and A8 formulations were found 0.3721 and 0.3932, respectively, confirmed that both the formulations followed pseudo Fickian diffusion (n < 0.43). The formulation A8 with the optimal drug release was identified as the best NEG formulation. Results of rheological, mucoadhesion and syringeability studies showed the suitability of desired sol-gel property for periodontal drug delivery. The Herschel-Bulkley model was the best fit model to explain the flow behavior of optimized formulation. Using the HET-CAM method, significantly lower in vitro toxicity was indicated the suitability of developed NEG for intra-pocket delivery.

Validated Stability−Indicating LC Method for Estimation of Amoxicillin Trihydrate in Pharmaceutical Dosage Forms and Time-Dependent Release Formulations

The objective of this study was to establish a validated stability-indicating LC method for routine analysis of amoxicillin trihydrate in bulk drug samples, different pharmaceutical formulations, and degradation kinetics of the drug under different ICH recommended stress conditions. Chromatographic separation was achieved by a Capacel Pak C18 column with 50:50% v/v methanol-0.02 M phosphate buffer as mobile phase having pH 3.5 and flow rate of 1.0 ml/min; with UV absorbance at 229 nm. The method was validated for system suitability, linearity, precision, accuracy, robustness, specificity and sensitivity. The drug was subjected to stress degradation by exposure to acid and alkaline hydrolysis, oxidation, and photodegradation. It was observed that peaks of all degradation products were well resolved from the pure drug with significantly different retention times, which indicated the specificity and stability-indicating properties of the method. When the utility of the method was verified by analysis of the drug in marketed formulations and in-house time-dependent release tablet formulations, the assay was found to be 99.6–100.4%. Statistical analysis proves that the method is repeatable, selective, and accurate for the estimation of amoxicillin trihydrate in bulk drug samples and also in pharmaceutical formulations. 

Distribution of malignant neoplasms reported at different pathology centers and hospitals in Jaipur, Rajasthan

BACKGROUND

Cancer data from Rajasthan are limited. Only two studies, one from Western Rajasthan, and the other from Eastern Rajasthan have been published by Sharma et al. in 1992 and 1996.

AIMS

To put the cancer profile from this region in proper perspective, we conducted the present study on the patterns of various malignancies in Jaipur region, i.e., Eastern Rajasthan. SETTING AND DESIGN AND MATERIAL AND METHODS: The study spans over one and half decade (1990-2004) and is based on a retrospective six-year sample analysis of approximately 200,000 histopathological and cytological reports for the years 1990, 1991, 1996, 1999, 2001 and 2004.

RESULTS

A total of 21,868 cancers were recorded in the six sample years. There were 59.11% (12,926) males and 40.89% (8942) females, with the male to female ratio being 1.45:1. Organ wise, lung (8.45%), prostate (7.12%), brain (6.04%), urinary bladder (5.31%), esophagus (4.67%) and tongue (4.60%) are most common sites involved in males with regard to frequency, whereas breast (20.44%), cervix (14.99%), ovary (4.35%), brain (3.80%), esophagus (3.67%), uterus (3.01%) and rectum (2.80%) are common sites for malignancies in females.

CONCLUSIONS

Significant findings were a higher frequency of cancers of the prostate, urinary bladder, and brain in males along with gall bladder cancers in females. Our figures have been compared with the national data.

Modulation of antiepileptic effect of phenytoin and carbamazepine by melatonin in mice

The pharmacokinetic and pharmacodynamic interaction of phenytoin and carbamazepine with melatonin was studied in a maximal electroshock seizure (MES) model in mice. The anticonvulsant ED(20), ED(33), ED(50) and ED(100) of phenytoin and carbamazepine, and ED(50) of melatonin were determined. Thereafter, the subanticonvulsant doses of phenytoin and carbamazepine were combined with ED(50) dose of melatonin. In combination with melatonin, 100% protection against seizures was achieved with phenytoin and carbamazepine in doses as low as ED(50) and ED(33), respectively. Serum levels of phenytoin and carbamazepine in animals that received ED(50) dose of phenytoin and carbamazepine per se, were not significantly different to those of the groups that received melatonin also. The study suggests that the synergistic antiepileptic effect is most likely a pharmacodynamic interaction, and not due to pharmacokinetic changes. Melatonin, thus, can be a potential adjunct to antiepileptic drugs, achieving a therapeutic effect at lower concentrations, hence limiting their dose-related toxicities.

Development and evaluation of a microemulsion formulation for transdermal delivery of terbinafine

The aim of the present study is to develop and evaluate microemulsion formulations for Terbinafine (TB) with a view to enhance its permeability through the skin and provide release for 24 h. Various o/w microemulsions were prepared by the spontaneous emulsification method. Oleic acid was chosen as the oil phase, Caprylo caproyl macrogol-8- glyceride (Labrasol S) and purified diethylene glycol monoethyl ether (Transcutol P) were used as surfactant and cosurfactant, respectively, on the basis of solubility studies. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant, cosurfactant, and water for microemulsion formulation. The optimized microemulsion consisted of 2% w/w TB, 8% w/w oleic acid, 31% w/w labrasol S, 31% w/w transcutol P, and 30% w/w distilled water. Permeability parameters like Jss and Kp were found to be significantly higher for formulation F4 as compared to other formulations (P < 0.05). Microbiological studies of TB in microemulsion showed better anti-fungal activity against Candida albicans and Aspergillus flavus as compared to marketed product (P < 0.05).

A reverse phase high performance liquid chromatography method for simultaneous estimation of melatonin, carbamazepine epoxide and carbamazepine simultaneously in serum

Monitoring of plasma antiepileptic drugs is useful for better clinical management in epileptic patients, particularly in children. Carbamazepine (CBZ) is one of the commonly prescribed anticonvulsants. The active metabolite of carbamazepine-carbamazepine-10-11 epoxide (CBZ-Epo) also exhibits anticonvulsant effect. The pineal hormone, melatonin exerts an anticonvulsant effect in experimental seizure models and recently has also been used in cases of childhood epilepsy. To facilitate the simultaneous plasma estimation of carbamazepine, carbamazepine epoxide, and melatonin, a new HPLC method was developed. Waters millennium 2010 chromatography manager with a 515 HPLC pump and Waters 24879 dual absorbance UV detector was used. A 25 microlitre of sample and standards were injected, and chromatographic separation was achieved by Merck C18 reverse phase column particle size 5 micro, 250 mm x 4 mm. It was quantitated at UV light 210 nm. The retention times of melatonin, CBZ-Epo, and CBZ were 6.3 min, 7.5 min, and 13.9 min respectively. The Mobile Phase used was water: acetonitrile (70:30), pH 3.0 adjusted with orthophosphoric acid at the flow rate of 1 ml/min. The limits of detection of melatonin, carbamazepine epoxide, and carbamazepine were 800, 500, and 1300 pg respectively.

Stability indicating high-performance thin-layer chromatographic determination of gatifloxacin as bulk drug and from polymeric nanoparticles

A simple, sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method for determination of gatifloxacin both as a bulk drug and from polymeric nanoparticles was developed and validated as per the International Conference on Harmonization (ICH) guidelines. The method employed thin-layer chromatography (TLC) aluminium plates precoated with silica gel 60F-254 as the stationary phase and the mobile phase consisted of n-propanol-methanol-concentrated ammonia solution (25%) (5:1:0.9, v/v/v). This solvent system was found to give compact spots for gatifloxacin (R(f) value of 0.60+/-0.02). Densitometric analysis of gatifloxacin was carried out in the absorbance mode at 292 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r=0.9953 with respect to peak area in the concentration range of 400-1200 ng spot(-1). The mean value (+/-S.D.) of slope and intercept were 9.66+/-0.05 and 956.33+/-27.67, respectively. The method was validated for precision, accuracy, ruggedness and recovery. The limits of detection and quantitation were 2.73 and 8.27 ng spot(-1), respectively. Gatifloxacin was subjected to acid and alkali hydrolysis, oxidation, photodegradation and dry heat treatment. The drug undergoes degradation under acidic and basic conditions and upon wet and dry heat treatment. The degraded products were well separated from the pure drug. The statistical analysis proves that the developed method for quantification of gatifloxacin as bulk drug and from polymeric nanoparticles is reproducible and selective. As the method could effectively separate the drug from its degradation products, it can be employed as stability-indicating one.

Formulation and evaluation of once a day transdermal gels of diclofenac diethylamine

The present study was undertaken to prepare and evaluate transdermal gels of diclofenac diethylamine (DDEA) containing penetration enhancers such as olesan oil and dimethyl sulfoxide (DMSO). Transdermal gels were prepared using different polymers such as carbopol-940, polyvinyl alcohol (PVA), hydroxy propyl methyl cellulose-K(4) M, hydroxy propyl cellulose-M, and sodium carboxy methyl cellulose. The formulated gels were subjected to physicochemical studies, in vitro release studies and in vitro skin permeations studies and were evaluated for drug content, viscosity, extrudability, spreadability, and pH. The in vitro release studies of prepared gels were performed using specially designed Fites cell and in vitro skin permeation studies were performed using keshary-chien diffusion cell through rat skin. Selected formulations were evaluated for their antiinflammatory activity using the carrageenan-induced paw edema in rats. The carbopol-940 and PVA gels containing 10% DMSO showed best in vitro skin permeation of DDEA. In vivo study for the selected formulation showed a sustained reduction in inflammation in the carrageenan induced paw edema in rats. The efficacies of carbopol-940 and PVA gels were also compared with that of the marketed Voveran gel,(R) and it was found that carbopol and PVA gels produced better results than the Voveran gel. (c) 2006 Prous Science. All rights reserved.

Stability-indicating HPTLC determination of curcumin in bulk drug and pharmaceutical formulations

A simple, selective, precise and stability-indicating high-performance thin-layer chromatographic method of analysis of curcumin both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60 F-254 as the stationary phase. The solvent system consisted of chloroform:methanol (9.25:0.75 v/v). This system was found to give compact spots for curcumin (R(f) value of 0.48 +/- 0.02). Densitometric analysis of curcumin was carried out in the absorbance mode at 430 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r = 0.996 and 0.994 with respect to peak height and peak area, respectively, in the concentration range 50-300 ng per spot. The mean value +/- S.D. of slope and intercept were 1.08 +/- 0.01, 51.93 +/- 0.54 and 8.39 +/- 0.21, 311.55 +/ -3.23 with respect to peak height and area, respectively. The method was validated for precision, recovery and robustness. The limits of detection and quantitation were 8 and 25 ng per spot, respectively. Curcumin was subjected to acid and alkali hydrolysis, oxidation and photodegradation. The drug undergoes degradation under acidic, basic, light and oxidation conditions. This indicates that the drug is susceptible to acid, base hydrolysis, oxidation and photo oxidation. Statistical analysis proves that the method is repeatable, selective and accurate for the estimation of said drug. As the method could effectively separate the drug from its degradation product, it can be employed as a stability-indicating one.

Molecular inclusion of rofecoxib with cyclodextrin: pharmacological properties in laboratory animals

Rofecoxib is practically insoluble in water and its prolonged use is associated with the incidence of side effects like gastrointestinal perforations, ulcerations and bleeding. Therefore, an attempt has been made to improve the aqueous solubility of the drug by making an inclusion complex using dimethyl-beta-cyclodextrin (DIMEB). The complexes were prepared by kneading and by the spray drying method. The prepared complexes showed better anti-inflammatory activity and decreased ulcerogenic potential than the pure drug.

Current drug therapy of protozoal diarrhoea

Protozoal infections of the gastrointestinal tract occur worldwide and have substantial morbidity and mortality. Prevalence is higher in the economically deprived regions of the world, especially the developing countries. Infections like amoebiasis and giardiasis have a worldwide distribution, being endemic in India. Apart from producing GI symptoms, growth and development of children is also impaired. It is seen that protozoa multiply rapidly in their hosts and as there is a lack of effective vaccines, chemotherapy has been the only practiced way to treat individuals and reduce transmission. The current treatment modalities for protozoal diarrhoea include 5-nitrosoimidazoles, iodoquinol, diloxanide furoate, paromomycin, chloroquine, and trimethoprim-sulphamethoxazole.

Neuroprotective role of melatonin in oxidative stress vulnerable brain

The brain is deficient in oxidative defense mechanisms and hence is at greater risk of damage mediated by reactive oxygen species (ROS) resulting in molecular and cellular dysfunction. Emerging evidence suggesting the activation of glutamate gated cation channels, may be another source of oxidative stress, leading to neuronal degeneration. Oxidative stress has been implicated in the development of neurodegenerative diseases like Parkinsonism, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, epileptic seizures, and stroke. Melatonin, the pineal hormone, acts as a direct free radical scavenger and indirect antioxidant. It is suggested that the increase in neurodegenerative diseases is attributable to a decrease in the levels of melatonin with age. Melatonin has been shown to either stimulate gene expression for the antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase) or to increase their activity. Additionally, it neutralizes hydoxyl radical, superoxide radical, peroxyl radical, peroxynitrite anion, singlet oxygen, hydrogen peroxide, nitric oxide, and hypochlorous acid. Unlike other antioxidants, melatonin can easily cross all morphophysiological barriers, e.g., the blood brain barrier, and enters cells and subcellular compartments. Though evidence are accumulating to suggest the potential of melatonin in neurodegenerative conditions, much information needs to be generated before the drug can find place in neurology clinics.

A survey of local and topical anesthesia use by pediatric dentists in the United States

PURPOSE

The purpose of this survey is to evaluate current usage of local and topical anesthesia by Pediatric Dentist to evaluate the current practices.

METHODS

Surveys were sent to 3051 pediatric dentists asking about types of anesthetics, considerations in determining local anesthetic dosage, time used to inject a cartridge and shortcomings of topical preparations. Data were computed for percentage responses.

RESULTS

The response rate was 55%. Only 49% used exact body weight to determine local anesthetic dosage. The mostly commonly used needles for infiltrations were 30-gauge short and blocks were 27-gauge short. Only 11% of the respondents were using > or = 60 seconds to inject a full cartridge. Topical anesthetics were used by most, with the most commonly used brand being Hurricaine [correction of Hurricane]. A third waited 60 seconds before injecting after the application of the topical anesthetic. Most patients (89%) disliked the taste of topical anesthetics and adverse drug reactions were rarely seen.

CONCLUSIONS

The findings of this study demonstrate that Pediatric Dentists are most commonly using Lidocaine as the preferred type of local anesthetic using 30 gauge short needle for infiltrations and 27 gauge short needle for blocks. Most were taking anywhere from 11-> 60 seconds to inject a cartridge. Topical anesthetic was used by most and the preferred brand was Hurricaine, however their perception of the effectiveness of topical anesthetics varied. There also appears to be a need to develop newer and better mode of topical anesthetic delivery system in the pediatric dental population.

A comparison of dental and dentoalveolar changes between rapid palatal expansion and nickel-titanium palatal expansion appliances

A tandem-loop nickel titanium temperature-activated palatal expansion appliance was developed that produces light, continuous pressure on the midpalatal suture and requires little patient cooperation or laboratory work. The purpose of this study was to compare the effectiveness of the nickel titanium palatal expansion appliance with that of a rapid palatal expansion appliance. The study sample comprised 25 patients who required palatal expansion as part of their orthodontic treatment. The sample was divided into 2 groups, with 13 patients in the nickel titanium group and 12 patients in the rapid palatal expansion group. Study models were taken before treatment and at the end of the retention period after expansion. Intermolar width, palatal width, palatal depth, alveolar tipping, molar tipping, and molar rotation were analyzed. In addition, occlusal radiographs were obtained before and 2 weeks after expansion to evaluate for sutural separation by the appliances. Results showed significant increases in midpalatal sutural separation, tipping of the alveolus, and tipping of the molars after expansion in both groups. However, greater midpalatal sutural separation was found in the rapid palatal expansion group and greater molar rotation was found in the nickel titanium group. Stepwise multiple regression analysis showed that alveolar tipping, palatal width change, and molar tipping are the best predictors of intermolar width change in the rapid palatal expansion group. Radiographic evidence of midpalatal sutural separation was less obvious in the nickel titanium group. These results suggest that both the nickel titanium and the rapid palatal expansion appliances are capable of expanding the maxillary dentition and alveolar process and are equally capable of correcting posterior crossbites. In the current study, the rapid palatal expander widened the palate more reliably, whereas the nickel titanium expander tipped the molars buccally to a greater extent and caused more distal molar rotation. The clinician's choice of expander will depend on his or her initial diagnosis and treatment goals.

Carbamazepine and valproate monotherapy: feasibility, relative safety and efficacy, and therapeutic drug monitoring in manic disorder

RATIONALE

Search for alternatives to lithium therapy for mood disorders commenced with anticonvulsants, carbamazepine (CBZ) and valproic acid (VPA), in the late 1970s. The comparative safety and efficacy data of CBZ and VPA monotherapy in patients with bipolar disorder remain to be established.

OBJECTIVES

The main objectives of the study were to assess the relative antimanic efficacy and safety of CBZ and VPA; to study the feasibility of using either, as a first line anti-manic agent; to investigate and generate clinically relevant parameters involving therapeutic drug monitoring of the two drugs.

METHODS

After a 2-day screening period, suitable patients (n = 30) were randomly assigned to treatment with CBZ or VPA. Both the drugs were started with an average dose of approximately 20 mg/kg body weight per day. Further increment in dose was carried out at weekly intervals, guided by clinical improvement, serum levels and treatment emergent adverse events. The primary efficacy measure in the protocol was defined as a change from baseline to endpoint in total score on the Young Mania Rating Scale. A favourable clinical response was defined a priori as a decrease of more than 50% from baseline in Young Mania Rating Scale total score.

RESULTS

Both CBZ and VPA were found to be efficacious as single first-line anti-manic agents, however VPA proved to be better. Using the intent-to-treat analysis, the VPA group showed a significant fall in YMRS total scores after week 1 while the CBZ group showed a significant fall after week 2. In the primary efficacy analysis, valproate group experienced significantly greater mean improvement in Young Mania Rating Scale total score than the CBZ group. Of the VPA treated patients, 73% showed a favourable clinical response while 53% of the patients on CBZ responded favourably. In the CBZ group, significantly more patients received rescue medication during the week 2 and the requirement was quantitatively more as compared to the VPA group. The steady state serum concentration (Css) of CBZ ranged from 3 to 9 micrograms/ml; however, it did not appear to correlate with the dose or clinical response. The Css of VPA ranged from 50 to 100 micrograms/ml; a linear correlation was found between the dose and serum levels of VPA as well as between weekly rise in serum levels and clinical response. Weekly dose escalations of VPA also correlated positively with corresponding rise in serum levels. Significantly more patients in the CBZ group reported adverse events, including nausea, vomiting and dizziness, than VPA.

CONCLUSIONS

The findings from this study suggest that both CBZ and VPA monotherapy is feasible for treatment of acute mania; however, VPA is more efficacious in terms of its early onset of action, lesser requirement for rescue medication and better tolerability. Further work needs to be undertaken to characterise the manic patients in terms of their differential psychopharmacologic response profile.

Identification of amino acids in the tau 2-region of the mouse glucocorticoid receptor that contribute to hormone binding and transcriptional activation

The tau 2-region of steroid hormone receptors is a highly conserved region located at the extreme N-terminal end of the hormone-binding domain. A protein fragment encoding tau 2 has been shown to function as an independent transcriptional activation domain; however, because this region is essential for hormone binding, it has been difficult to determine whether the tau 2-region also contributes to the transactivation function of intact steroid receptors. In this study a series of amino acid substitutions were engineered at conserved positions in the tau 2-region of the mouse glucocorticoid receptor (mGR, amino acids 533-562) to map specific amino acid residues that contribute to the hormone-binding function, transcriptional activation, or both. Substitution of alanine or glycine for some amino acids (mutations E546G, P547A, and D555A) reduced or eliminated hormone binding, but the transactivation function of the intact GR and/or the minimum tau 2-fragment was unaffected for each of these mutants. Substitution of alanine for amino acid S561 reduced transactivation activity in the intact GR and the minimum tau 2-fragment but had no effect on hormone binding. The single mutation L550A and the double amino acid substitution L541G+L542G affected both hormone binding and transactivation. The fact that the S561A and L550A substitutions each caused a loss of transactivation activity in the minimum tau 2-fragment and the full-length GR indicated that the tau 2-region does contribute to the overall transactivation function of the full-length GR. Overall, the N-terminal portion of the tau 2-region (mGR 541-547) was primarily involved in hormone binding, whereas the C-terminal portion of the tau 2-region (mGR 548-561) was primarily involved in transactivation.

GRIP1, a transcriptional coactivator for the AF-2 transactivation domain of steroid, thyroid, retinoid, and vitamin D receptors

After binding to enhancer elements, transcription factors require transcriptional coactivator proteins to mediate their stimulation of transcription initiation. A search for possible coactivators for steroid hormone receptors resulted in identification of glucocorticoid receptor interacting protein 1 (GRIP1). The complete coding sequence for GRIP1, isolated from a mouse brain cDNA library, contains an open reading frame of 1,462 codons. GRIP1 is the probable ortholog of the subsequently identified human protein transcription intermediary factor 2 (TIF2) and is also partially homologous to steroid receptor coactivator 1 (SRC-1). The full-length GRIP1 interacted with the hormone binding domains (HBDs) of all five steroid receptors in a hormone-dependent manner and also with HBDs of class II nuclear receptors, including thyroid receptor alpha, vitamin D receptor, retinoic acid receptor alpha, and retinoid X receptor alpha. In contrast to agonists, glucocorticoid antagonists did not promote interaction between the glucocorticoid receptor and GRIP1. In yeast cells, GRIP1 dramatically enhanced the transcriptional activation function of proteins containing the HBDs of any of the above-named receptors fused to the GAL4 DNA binding domain and thus served as a transcriptional coactivator for them. This finding contrasts with previous reports of TIF2 and SRC-1, which in mammalian cells enhanced the transactivation activities of only a subset of the steroid and nuclear receptors that they physically interacted with. GRIP1 also enhanced the hormone-dependent transactivation activity of intact glucocorticoid receptor, estrogen receptor, and mineralocorticoid receptor. Experiments with glucocorticoid receptor truncation and point mutants indicated that GRIP1 interacted with and enhanced the activity of the C-terminal AF-2 but not the N-terminal AF-1 transactivation domain of the glucocorticoid receptor. These results demonstrate directly that AF-1 and AF-2 domains accomplish their transactivation activities through different mechanisms: AF-2 requires GRIP1 as a coactivator, but AF-1 does not.

Fluoride uptake by proximal surfaces from professionally applied fluorides: an in vitro study

This study was performed to examine the uptake of fluoride by mesial enamel surfaces of extracted teeth from different types of topical fluoride. Forty-eight extracted human molars and twelve premolars were randomly divided into four groups and mounted in twelve wax blocks with five teeth in proximal contact in each block. Each group was treated for four minutes with either 1.23 percent acidulated phosphofluoride conventional gel, thixotropic gel, or foam in lined trays, or 2 percent neutral sodium fluoride solution applied with a cotton tip applicator. Acid-etch biopsies were performed three times to indicate the amount of fluoride uptake at three different depths. The results demonstrated that there was a statistically significant increase in fluoride uptake in the surface layer with both gels and foam (1150, 1058 and 1120 ppm F), whereas there was an insignificant increase with the fluoride solution (27 ppm F). In the deepest layer, the thixotropic fluoride produced the greatest fluoride uptake (919 ppm F) in comparison with the uptake from conventional gel (383 ppm F), foam (297 ppm F), or solution (118 ppm F).

GRIP1, a novel mouse protein that serves as a transcriptional coactivator in yeast for the hormone binding domains of steroid receptors

The yeast two-hybrid system was used to isolate a clone from a 17-day-old mouse embryo cDNA library that codes for a novel 812-aa long protein fragment, glucocorticoid receptor-interacting protein 1 (GRIP1), that can interact with the hormone binding domain (HBD) of the glucocorticoid receptor. In the yeast two-hybrid system and in vitro, GRIP1 interacted with the HBDs of the glucocorticoid, estrogen, and androgen receptors in a hormone-regulated manner. When fused to the DNA binding domain of a heterologous protein, the GRIP1 fragment activated a reporter gene containing a suitable enhancer site in yeast cells and in mammalian cells, indicating that GRIP1 contains a transcriptional activation domain. Overexpression of the GRIP1 fragment in mammalian cells interfered with hormone-regulated expression of mouse mammary tumor virus-chloramphenicol acetyltransferase gene and constitutive expression of cytomegalovirus-beta-galactosidase reporter gene, but not constitutive expression from a tRNA gene promoter. This selective squelching activity suggests that GRIM can interact with an essential component of the RNA polymerase II transcription machinery. Finally, while a steroid receptor HBD fused with a GAL4 DNA binding domain did not, by itself, activate transcription of a reporter gene in yeast, coexpression of this fusion protein with GRIP1 strongly activated the reporter gene. Thus, in yeast, GRIP1 can serve as a coactivator, potentiating the transactivation functions in steroid receptor HBDs, possibly by acting as a bridge between HBDs of the receptors and the basal transcription machinery.

Rational drug therapy as evaluated from student's clinical case reports

210 prescriptions selected by students from Sucheta Kriplani and R.M.L. Hospitals were subjected to audit prescription in a group discussion with faculty members in the Department of Pharmacology of Lady Hardinge Medical College, New Delhi. It was observed that inadequate treatment was prescribed to the patients suffering from common diseases like amoebiasis, tuberculosis and typhoid fever. Indiscriminate use of antibiotics, antihistaminics, NSAID, vitamins and haematinics was a common observation.

A somatic cell genetic method for identification of untargeted mutations in the glucocorticoid receptor that cause hormone binding deficiencies

Mouse T lymphoma cell line W7MG1, which is killed by physiological concentrations of glucocorticoid agonists, was used as a convenient genetic system for isolating sublines containing mutant glucocorticoid receptors (GR) with hormone-binding deficiencies. Partially hormone-resistant cell clones were derived from chemically mutagenized cell populations by selecting for growth in moderate concentrations of dexamethasone (Dex) and then screening for failure to grow in high Dex concentrations. Such clones are likely to have mutant GR. In GR cDNA clones from the partially resistant cell sublines, three different functionally significant mutations in the hormone-binding domain were identified: Leu-569 changed to Phe (L569F), Leu-670 to Phe (L670F), and Met-672 to Ile (M672I). Dose-response analyses with Dex and affinity labeling studies with dexamethasone 21-mesylate in transiently transfected cells indicated that all three mutant GR species had hormone-binding deficiencies. However, at saturating Dex concentrations the mutant and wild type GR activated a hormone-inducible reporter gene to the same extent; thus, these three mutations did not affect the ability of GR to activate transcription of the reporter gene after hormone was bound. In dose-response curves conducted with several glucocorticoid agonists, mutations L670F and M672I caused no change in ligand-binding specificities, while mutation L569F caused a modest change in specificity. Quantitative hormone-binding studies conducted with mutant GR synthesized in cell-free reactions showed that mutant GR species L569F and M672I had reduced Dex-binding affinities both at 0 C and at 22 C in the presence of molybdate. In contrast, for the L670F mutant, which exhibited the severest deficiency in vivo, the hormone-binding deficiency in the cell-free system was evident only at 26-37 C and primarily in the absence of molybdate. We propose that the L670F GR is an activation-labile type of mutant, which binds hormone normally in the presence of heat shock protein 90 but loses hormone rapidly after dissociation from heat shock protein 90. These three mutations define two new subregions of the GR polypeptide that are important for hormone binding.

Genetic analysis of the N-terminal end of the glucocorticoid receptor hormone binding domain

Four site-directed missense mutations were constructed at the N-terminal end of the mouse glucocorticoid receptor (GR) hormone binding domain. This small subdomain is highly conserved among the steroid hormone receptors and is within a larger subregion believed to be important for hormone binding, transcriptional activation, and hsp90 binding. The ability of mutant and wild type GR to activate a reporter gene in response to various concentrations of dexamethasone was examined in transiently transfected COS-7 cells. Mutant GR species V544G (valine-544 changes to glycine) and V549G activated the reporter gene to approximately the same extent as wild type GR, but required approx. 7 and 23 times greater hormone concentrations, respectively. In contrast, double mutant LL541/2GG (leucines changed to glycines) could not activate transcription even at 10 microM dexamethasone or deacylcortivazol, while E543A (glutamic acid to alanine) was functionally indistinguishable from wild type GR. GR mutants LL541/2GG and V549G had reduced abilities to bind covalently to affinity label dexamethasone 21-mesylate. The partially and fully functional mutant GR species had no deficiency in transcriptional transactivation activity in the presence of saturating concentrations of agonist.

Phenylalanine-780 near the C-terminus of the mouse glucocorticoid receptor is important for ligand binding affinity and specificity

Site-directed mutagenesis was employed to make two single amino acid substitutions for highly conserved amino acid residues near the C-terminus of the 783-amino acid mouse glucocorticoid receptor. Substitution of leucine for histidine-781 caused little or no change in the concentration of dexamethasone required for half-maximal activation of a chloramphenicol acetyltransferase reporter gene expressed from a mouse mammary tumor virus promoter. However, when phenylalanine-780 was changed to alanine, the half-maximal concentrations of various agonists were increased as follows, compared with the wild-type glucocorticoid receptor: triamcinolone acetonide by 7-fold, dexamethasone by 25-fold, and hydrocortisone and deoxycorticosterone by more than 150-fold. Binding of labeled steroids by the mutant receptor in vitro and in vivo was also decreased. In contrast, this mutation caused a small decrease in the concentration of RU486 required for antagonist or partial agonist activity. Thus, the phenyl group of phenylalanine-780 of the mouse glucocorticoid receptor is an important determinant of ligand binding affinity and specificity.