A calorimeter for the study of photoproduction at high transverse momentum

Imperial Users onl

Development of novel carriers for transdermal delivery of peptides

Recent developments in genetic engineering and biotechnology have resulted in anincrease in availability of therapeutic peptides and small anti-cytokines. Oraladministration is inappropriate as these molecules are unstable in the gastrointestinaltract and are subject to hepatic first-pass effect. Transdermal delivery is an attractivealternative as the skin exhibits less enzymatic activity and allows for a controlled,sustained local therapeutic drug concentration over a prolonged period of time.However, the skin’s lipophilic stratum corneum acts as a major barrier to thedelivery of hydrophilic molecules, including peptides, resulting in lack of efficacy ofthese compounds if applied topically. Considerable research effort has beenfocussed on the development of skin penetration enhancement techniques. However,many of these techniques have been limited by insufficient penetration enhancementand/or induced irritancy.We have investigated three approaches to enhance the delivery of peptides that havetherapeutic or cosmetic effect in the skin. These approaches include the use ofphysical energy to enhance the delivery of Alanine-Tryptophan (Ala-Trp), lipoaminoacid (LAA) conjugation to increase the permeability of a HNE inhibitor Ala-Ala-Pro-Val (AAPV) and a cosmetic peptide, acetyl hexapeptide-3 and cyclisation to enhancethe delivery of a core peptide (CP) which has anti-inflammatory activity.In vitro permeation studies across human epidermis were performed in Pyrex glassFranz-type diffusion cells. Ala-Trp was selected as a small molecular weight modeldipeptide to study the penetration enhancement effects of Dermaportation, which is anewly developed pulsed electro magnetic field (PEMF) technology. The dipeptidewas found to be unstable on exposure to skin at 37°C and Dermaportation (Pulsedelectromagnetic field technology) significantly increased the in vitro permeabilitycoefficient of Ala-Trp across human epidermis from 7.7 x 10-4 cm/h with passivediffusion to 1.94 x 10-2 cm/h with Dermaportation over an 8 h period.Dermaportation thus may provide an effective means of delivering molecules that arehighly susceptible to degradation like dipeptides, in higher amounts and in arelatively short duration.The effectiveness of coupling a short chain lipoamino acid to enhance transepidermaldelivery of a model human neutrophil elastase (HNE) inhibitor (Ala-Ala-Pro-Val) was assessed. The optimal conjugate structure for skin penetration andbiological activity of this therapeutic peptide with anti-inflammatory activity wasdetermined. In order to enhance the trans-epidermal delivery of the peptide,lipophilic derivatives with LAAs of chain length C6, C8, and C10 were prepared bysolid phase synthesis. Conjugation to a C6-LAA enhanced epidermal permeability ofthe tetrapeptide. Stereoselective permeation of the lipopeptide diastereomers acrossthe human epidermis was observed. The amount of C6(D)-LAA-AAPV (467.94μg/cm2) was significantly higher than C6(L)–LAA-AAPV (123.04 μg/cm2). Thesame was observed with C8(D)-LAA-AAPV. The effect of donor concentration andskin hydration on skin permeability of C8(D,L)-LAA-AAPV and C10(D,L)-LAAAAPVwas also assessed and it was observed that there was higher permeation ofC10(D,L)-LAA-AAPV at a higher donor concentration. The lipoamino acid conjugates were more stable than the native tetrapeptide and biological activity was retained after coupling of the tetrapeptide to C6, C8 and C10 LAA.A cosmetic peptide, acetyl hexapeptide-3 was coupled to individual diastereomers ofC12 (A)-LAA and C12 (B)-LAA. The preliminary study was designed to assess theeffect of coupling of a LAA of higher molecular weight on the transepidermalpermeation and accumulation of this hexapeptide. Accumulation of these peptides inthe skin was also quantified. Detectable amounts of C12(A)-LAA-hexapeptide-3 andC12(B)-LAA-hexapeptide-3 were not found in the receptor solution but higherquantities of these conjugates were found to be retained in the skin. The amount ofC12(B)-LAA-hexapeptide-3 (59.92 μg/cm2 ± 10.64) in the epidermis was highestfollowed by C12(A)-LAA-hexapeptide-3 (33.06 μg/cm2 ± 3.70) and acetylhexapeptide-3 (12.64 μg/cm2 ± 1.48).Lastly, skin permeability and in skin stability of an anti-inflammatory peptide (corepeptide: CP) and two analogues that have demonstrated improved biological efficacyand specificity: a cyclic peptide sequence (C1) and its linear sequence counterpart(C1-L) were assessed. The stability of C1 and C1-L was significantly higher ascompared to CP when placed in contact with skin at 37ºC. The epidermal penetrationof the core anti-inflammatory peptide improved after cyclisation. The order of Lastly, skin permeability and in skin stability of an anti-inflammatory peptide (corepeptide: CP) and two analogues that have demonstrated improved biological efficacyand specificity: a cyclic peptide sequence (C1) and its linear sequence counterpart(C1-L) were assessed. The stability of C1 and C1-L was significantly higher ascompared to CP when placed in contact with skin at 37ºC. The epidermal penetrationof the core anti-inflammatory peptide improved after cyclisation. The order of permeation of the analogues was C1>C1-L>CP after 48h and 6 days. The amount of peptide retained in the skin was higher after 48h as compared to 8h due to greater partitioning of these peptides in the skin.This work demonstrates the enhancement effects of these three techniques tooptimize the transdermal/topical permeation of therapeutic and cosmetic peptides

Effect of blood storage on electrolyte levels

Background: Blood transfusion can be an immediate life saving measure in several acute conditions such as hemorrhage and anemia. However, various post transfusion complications are observed in patients which may be associated with the storage conditions of the collected blood. Electrolytes play a major role in maintaining homeostasis within the cells. Potassium is the most important extracellular cation responsible for maintenance of the cell integrity. Prolonged and improper storage of blood can lead to leakage of electrolytes, thus changing the cell morphology. This can adversely affect the patients who receive such blood. This study helps us analyze the effect of blood storage on electrolyte levels.Methods: For the study, 10ml of blood was collected from 30 blood bags containing CPDA-1 at the time of blood donation from 30 different volunteers. This blood containing the CPDA-1 was divided into 5 parts of 2ml and each 2ml sample was stored in plain bulbs. All the samples were stored at 4°C. Samples were tested to check for changes in the electrolyte (Na+, K+, Cl-) levels on day 0, 3, 7, 14 and 21. ANOVA was used to calculate the variance in the electrolyte levels.Results: Average sodium level on day 0 was 152.9±3.8 mEq/l. There was a significant decrease and it was measured at 139.5±4.8 mEq/l on day 21. Average potassium level on day 0 was 4.2±0.4 mEq/l. A significant spike was observed in potassium levels. The final reading of potassium level on day 21 was 15.2±0.7 mEq/l. Average chloride level on day 0 was 71.9±6.6 mEq/l which significantly declined to 67±5.9 mEq/l.Conclusions: Though blood is stored in proper conditions, a biochemical change occurs within the cells due to prolonged storage and thus affects its viability

Safety and efficacy of an oral insulin (Capsulin) in patients with early‐stage type 2 diabetes: a dose‐ranging phase IIb study

Aim This randomised, twelve-week open-label study compared the pharmacodynamic properties of different dose of regular human insulin administered in capsule form twice daily. Methods 100 persons (48 male, 52 female) with type 2 diabetes on metformin completed the study according to protocol. Mean (SD) age 48.5 (6.7) years, BMI 25.7 (2.8) kg/m2, HbA1c 8.10 (0.65) %. Subjects randomised on admission were assigned to one of three groups receiving 75iu BD of formulated regular insulin or 150iu insulin BD, or 300iu BD in enteric-coated capsules. Primary and secondary endpoints were change from baseline in HbA1c and FPG respectively. A total of 100 subjects from 15 different centres completed the study within protocol. Results The study met its primary clinical endpoint of a decrease in HbA1c ≥ 0.5% (least square mean decrease 0.52%; p = 0.004, median decrease 0.6) in the dose group receiving 150iu BD. In a subset of this population, with starting HbA1c values between 9 and 9.5%, an average decrease of 1.575% was seen. In the total population, least square mean decreases in HbA1c for groups 75iu BD and 300iu BD were -0.11% and -0.42% respectively. Mean change in FPG in the 150iu BD dose group was -18.8mg/dL (p = 0.017) and -14.8 and -2.7mg/dL for groups 75iu BD and 300iu BD respectively. A decrease of 20% for triglycerides (-40 mg/dL) was seen in the 150iu BD dose group . No significant increases in body weight were observed, and significant decreases in systolic blood pressure were seen in all groups. No serious treatment-related adverse events were recorded, and no incidence of hypoglycaemia was reported throughout the whole twelve-week study period. Conclusions Capsulin oral insulin administered twice per day at a dose of 150iu per capsule is safe, with no confirmed treatment-linked hypoglycaemic events, and results in significant decreases from baseline in HbA1c, Fasting Plasma Glucose and triglycerides

Recency of immersion in L2 environment more important than L2 proficiency in speech segmentation

Speech segmentation is a language-specific skill: each language provides different cues for optimally segmenting the continuous speech stream into words. When exposed to a novel language, listeners have been shown to use those segmentation cues that they are familiar with from their native language (L1)

Antagonism of triazolam self-administration in rhesus monkeys responding under a progressive-ratio schedule: In vivo apparent pA2 analysis.

BACKGROUND: Conventional benzodiazepines bind non-selectively to GABAA receptors containing α1, α2, α3, and α5 subunits (α1GABAA, α2GABAA, α3GABAA, and α5GABAA receptors, respectively), and the role of these different GABAA receptor subtypes in the reinforcing effects of benzodiazepines has not been characterized fully. We used a pharmacological antagonist approach with available subtype-selective ligands to evaluate the role of GABAA receptor subtypes in the reinforcing effects of the non-selective conventional benzodiazepine, triazolam. METHODS: Rhesus monkeys (n=4) were trained under a progressive-ratio schedule of intravenous midazolam delivery and dose-response functions were determined for triazolam, in the absence and presence of flumazenil (non-selective antagonist), βCCT and 3-PBC (α1GABAA-preferring antagonists), and XLi-093 (α5GABAA-selective antagonist). RESULTS: Flumazenil, βCCT and 3-PBC shifted the dose-response functions for triazolam to the right in a surmountable fashion, whereas XLi-093 was ineffective. Schild analyses revealed rank orders of potencies of flumazenil=βCCT\u3e3-PBC. Comparison of potencies between self-administration and previous binding studies with human cloned GABAA receptor subtypes suggested that the potencies for βCCT and 3-PBC were most consistent with binding at α2GABAA and α3GABAA receptors, but not α1GABAA or α5GABAA receptor subtypes. CONCLUSIONS: Our findings were not entirely consistent with blockade of α1GABAA receptors and are consistent with the possibility of α2GABAA and/or α3GABAA subtype involvement in antagonism of the reinforcing effects of triazolam. The α5GABAA receptor subtype likely does not play a substantial role in self-administration under these conditions

Role of gamma-aminobutyric acid type A (GABAA) receptor subtypes in acute benzodiazepine physical dependence-like effects: evidence from squirrel monkeys responding under a schedule of food presentation.

RATIONALE: Assays of schedule-controlled responding can be used to characterize the pharmacology of benzodiazepines and other GABAA receptor modulators, and are sensitive to changes in drug effects that are related to physical dependence. OBJECTIVE: The present study used this approach to investigate the role of GABAA receptor subtypes in mediating dependence-like effects following benzodiazepine administration. METHODS: Squirrel monkeys (n = 6) were trained on a fixed-ratio schedule of food reinforcement. Initially, the response rate-decreasing effects of chlordiazepoxide (0.1-10 mg/kg; nonselective GABAA receptor agonist), zolpidem (0.032-1.0 mg/kg; α1 subunit-containing GABAA subtype-preferring agonist), and HZ-166 (0.1-10 mg/kg; functionally selective α2 and α3 subunit-containing GABAA receptor agonist) were assessed. Next, acute dependence-like effects following single injections of chlordiazepoxide, zolpidem, and HZ-166 were assessed with flumazenil (0.1-3.2 mg/kg; nonselective GABAA receptor antagonist). Finally, acute dependence-like effects following zolpidem administration were assessed with βCCt and 3-PBC (0.1-3.2 mg/kg and 0.32-10 mg/kg, respectively; α1 subunit-containing GABAA receptor antagonists). RESULTS: Chlordiazepoxide, zolpidem, and HZ-166 produced dose- and time-dependent decreases in response rates, whereas flumazenil, βCCT, and 3-PBC were ineffective. After the drug effects waned, flumazenil produced dose-dependent decreases in response rates following administration of 10 mg/kg chlordiazepoxide and 1.0 mg/kg zolpidem, but not following any dose of HZ-166. Further, both βCCT and 3-PBC produced dose-dependent decreases in response rates when administered after 1.0 mg/kg zolpidem. CONCLUSIONS: These data raise the possibility that α1 subunit-containing GABAA receptors play a major role in physical dependence-related behaviors following a single injection of a benzodiazepine