The use of non-human primates in regulatory toxicology: comments submitted by FRAME to the Home Office

The Home Office have circulated a document that summarises the discussions of a Primate Stakeholders Forum. The Forum took place in January 2004, and was convened to address the issues raised and the recommendations made in the Animal Procedures Committee 2002 report on the use of primates under the Animals (Scientific Procedures) Act 1986. The report emphasises the need for more resources focused on alternatives to toxicological testing in primates, including harmonising worldwide regulatory requirements, investigating the relevance of primate models, and improving the retrospective analysis of procedures involving primates. The document called for reasoned comments about the report to be submitted to the Home Office. In response, FRAME submitted a comprehensive paper, which evaluated each of the Animal Procedures Committees recommendations, along with the Home Office Forums comments. FRAME believes that, in coming to a decision as to whether primates should be used for regulatory testing, there must be full consideration of all the information available, including whether the ethological needs of any given species can be met prior to, during and following experimental use. Where these needs cannot be met, there must be a concerted effort to develop alternative models for research and testing. However, this should not detract from the ultimate goal of phasing out primate research altogether.     

Scientific procedures on living animals in Great Britain in 2003: the facts, figures and consequences

The statistics for animal procedures performed in 2003 were recently released by the Home Office. They indicate that, for the second year running, there was a significant increase in the number of laboratory animal procedures undertaken in Great Britain. The species and genera used, the numbers of toxicology and non-toxicology procedures, and the overall trends, are described. The implications of these latest statistics are discussed with reference to key areas of interest and to the impact of existing regulations and pending legislative reforms.     

Validation of a measure of subjective well-being: an abbreviated version of the day reconstruction method

Background

The study of well-being is becoming a priority in social sciences. The Day Reconstruction Method (DRM) was developed to assess affective states. The aim of the present study was to validate an abbreviated version of the DRM designed for administration in population studies, and to assess its test-retest properties.

Principal Findings

1560 adults from Jodhpur (India) were interviewed using an abbreviated version of the DRM, and a week later they were re-interviewed using the original long version of the DRM, after which the abbreviated version of the DRM was compared with the original version. A regression model considering interaction terms was employed to analyse the impact of sociodemographic characteristics on net affect. Test-retest reliability was assessed, and found to be moderate. Positive affect showed more test-retest reliability than negative affect, while net affect had more temporal stability than U-index. The affect of sets A, B, and C, taken together, had a moderate predictive ability compared with the affect obtained using the full version of the DRM: AUC = 0.67 for positive affect; 0.66 for net affect; 0.61 for negative affect; and 0.60 for the U-index. Household income, gender, and setting all had a significant impact on net affect.

Conclusions

Net affect and positive affect showed moderate temporal stability, whereas negative affect and the U-index showed fair temporal stability. Evaluating the affective state using the abbreviated version of the DRM provides a profile of the population similar to that of the full version. The results provide considerable support for using the short version of the DRM as an instrument to measure subjective well-being in large population surveys.     

Functional characterization,secondary structure prediction and analysis of ectoine biosynthesis genes from <Emphasis Type="Italic">Bacillus halodurans</Emphasis>: an osmolyte involved in stress tolerance

An open reading frame encoding the ectoine biosynthesis genes was cloned from the Bacillus halodurans genome. An expression plasmid containing the operon was introduced into Escherichia coli cells, and the recombinant ectoine was quantified. The secondary structure of ectoine biosynthesis proteins were predicted and was quite similar to that of reported proteins from eubacteria.     

The release dynamics of salicylic acid and tetracycline hydrochloride from the psyllium and polyacrylamide based hydrogels (II)

Psyllium, a medicinally active natural polysaccharide, has been modified with polyacrylamide to develop the hydrogels; those can act as the potential candidate for novel drug delivery systems. In the present studies, the release dynamics of model drugs (salicylic acid and tetracycline hydrochloride) from the drug-loaded hydrogels have been discussed, for the evaluation of the drug release mechanism and diffusion coefficients. It has been observed that diffusion exponent ‘n’ have 0.68 and 0.74 values and gel characteristic constant ‘k’ have 1.625 × 10⁻² and 1.272 × 10⁻² values, respectively, for the release of salicylic acid and tetracycline hydrochloride in distilled water from the drug loaded hydrogels. Therefore, drug release from the drug loaded hydrogels through Non-Fickian or Anomalous diffusion mechanism where the rate of drug diffusion and rate of polymer relaxation were comparable. The effect of pH on the release pattern of tetracycline has been studied by varying the pH of the release medium. However, in each release medium, the Initial diffusion coefficient was observed to be more than the late time diffusion coefficient.     

Non-hypertensive tetraPEGylated canine haemoglobin: correlation between PEGylation, O2 affinity and tissue oxygenation

TetraPEGylated canine Hb, [SP (succinimidophenyl)-PEG5K]4-canine-Hb, with PEGylation at its four reactive cysteine residues (a111 and b93) has been prepared and characterized. The hydrodynamic volume and the molecular radius of (SP-PEG5K)4-canine-Hb are intermediate to those of di- and hexaPEGylated human Hb as expected. However, the COP (colloidal osmotic pressure) of tetraPEGylated canine Hb is closer to that of hexaPEGylated human Hb than to that of diPEGylated human Hb. The O2 affinity of tetraPEGylated canine Hb is higher than that of canine Hb and comparable with that of hexaPEGylated Hb. The O2 affinity of tetraPEGylated canine Hb is not responsive to the presence of DPG (diphosphoglycerate) or chloride, but it retains almost full response to L-35, an allosteric effector that interacts at the aa-end of the central cavity. The tetraPEGylated canine Hb is vasoinactive in hamster in 10% top load infusion studies. It is also essentially non-hypertensive in an extreme exchange haemodilution protocol in hamster just as di- and hexaPEGylated human Hb. The O2 delivery by tetraPEGylated canine Hb is comparable with that of hexaPEGylated Hb but not as efficient as diPEGylated Hb. These results demonstrate that PEGylation-induced solution properties of PEG [poly(ethylene glycol)]-Hb conjugates are dictated by the level and chemistry of PEGylation and the interplay of these plays a critical role in tissue oxygenation. The studies imply the need to establish the right level (and/or pattern) of PEGylation and O2 affinity of Hb-PEG adducts in designing O2-carrying plasma volume expanders, and this remains the primary challenge in the design of PEGylated Hb as blood substitutes.     

Radiation crosslinked psyllium and polyacrylic acid based hydrogels for use in colon specific drug delivery

In order to utilize the psyllium husk, a medicinally important natural polysaccharide, to develop the hydrogels meant for the drug delivery, we have prepared psyllium and polyacrylic acid based polymeric networks by radiation-induced crosslinked copolymerization. Polymeric networks (hydrogels) thus formed were characterized with SEMs, FTIR and swelling studies. Swelling behavior of the hydrogels was studied as a function of monomer concentration in the hydrogels and temperature, pH and [NaCl] of the swelling medium. This paper discusses the swelling kinetics of the hydrogels and release dynamics of anticancer model drug 5-fluorouracil from the hydrogels for the evaluation of swelling and drug release mechanisms. It has been observed from the release dynamics of drug that diffusion exponent ‘n’ have 0.7, 0.8 and 0.7 values and gel characteristics constant ‘k’ have 9.13 × 10⁻³, 6.22 × 10⁻³ and 9.01 × 10⁻³ values for the release of 5-fluorouracil, respectively, in distilled water, pH 2.2 buffer and pH 7.4 buffer. The values of the diffusion exponent show that the release of drug from drug-loaded hydrogels has occurred through Non-Fickian diffusion mechanism. It has also been observed from the swelling and release of drug in the different pH buffer that the polymer matrix is pH responsive and can be exploited for the delivery of anticancer drug to the colon.     

Functional characterization of a small heat shock protein from <Emphasis Type=Italic>Mycobacterium leprae</Emphasis>

Background  

Small heat shock proteins are ubiquitous family of stress proteins, having a role in virulence and survival of the pathogen. M. leprae, the causative agent of leprosy is an uncultivable organism in defined media, hence the biology and function of proteins were examined by cloning M. leprae genes in heterologous hosts. The study on sHsp18 was carried out as the knowledge about the functions of this major immunodominant antigen of M. leprae is scanty.