Study of Parameters Involved in Specific Immunoadsorption of Apolipoprotein B

A therapeutic immunoadsorption system on immobilized and anti-apolipoprotein B as a plasma cholesterol lowering procedure was optimized. Several antibodies were compared and highest adsorption capacity was obtained with goat polyclonal antibodies. Optimum quantities of antibodies to be immobilized on the gel and quantities of apo-B to be applied to columns were determined. The amount of antibodies released from immunoadsorbents can be minimized by treatment with a 0.005% glutaraldehyde solution with an acceptable reduction rate of adsorption capacity. Each phase, adsorption and desorption respectively, were well-defined and synchronized so two columns could be used in parallel in an automated procedure.

In these conditions, the immunoadsorption system can efficiently, specifically and safely remove cholesterol and has to be subjected to clinical trials.

Specific Removal of Transthyretin from Plasma of Patients with Familial Amyloidotic Polyneuropathy: Optimization of an Immunoadsorption Procedure

Familial amyloidotic polyneuropathy is characterized by the presence in patients plasma of a genetic variant of transthyretin. No specific treatment has been found and extracorporeal immunoadsorption on immobilized anti-transthyretin antibodies appears as a potentially attractive procedure.

Parameters involved in specific immunoadsorption of transthyretin were studied and optimized. Several monoclonal anti-TTR antibodies were compared as affinity ligands and one of them was found to be suitable for such purposes. Optimum quantities of antibodies to be immobilized on the gel were determined. Three desorption agents were tested for regenerating immunoadsorbents and best results were obtained with basic variation of pH, allowing total desorption of TTR and possibility of multiple use without loss of adsorption capacity.

Simulation of an immunoadsorption procedure in well-defined conditions showed efficiency and specificity of adsorption to remove TTR and the system thus should be subjected to clinical trials.

Prevalence and correlates of hepatitis C infection among users of North America's first medically supervised safer injection facility

BACKGROUND

North America's first medically supervised safer injection facility (SIF) for illicit drug users was opened in Vancouver, Canada on 22 September 2003. We examined the prevalence and correlates of hepatitis C (HCV) infection among a representative cohort of SIF users.

METHODS

Users of the Vancouver SIF were selected at random and asked to enrol in the Scientific Evaluation of Supervised Injecting (SEOSI) cohort. At baseline, venous blood samples were collected and an interviewer-administered questionnaire was performed. Participants who were HCV-positive were compared with HCV-negative subjects using bivariate and logistic regression analyses.

RESULTS

Between 1 December 2003 and 30 July 2004, 691 participants were enrolled into the SEOSI cohort, among whom 605 (87.6%) were HCV-positive at baseline. Factors independently associated with HCV infection in logistic regression analyses included: involvement with the sex trade [adjusted odds ratio (AOR) 3.7, 95% confidence interval (CI) 2.1-6.1], history of borrowing syringes (AOR 1.8, 95%CI 1.1-2.9), and history of incarceration (AOR 2.6, 95%CI 1.5-4.4). Daily heroin use was protective against HCV infection (AOR 0.6, 95%CI 0.3-0.9).

CONCLUSION

The SIF has attracted injection drug users with a high burden of HCV infection and a substantial proportion of uninfected individuals. Although cross-sectional, this study provides some insight into historical risks for HCV infection among this population, and prospective follow-up of this cohort will be useful to determine if use of the SIF is associated with reduced risk behaviour and HCV incidence.

Locally differentiated cryptic pigmentation in the freshwater isopod Asellus aquaticus

A repeated pattern of background colour matching in animals is an indication that pigmentation may be cryptic. Here, we examine the relationship between pigmentation of the freshwater isopod Asellus aquaticus and background darkness in 29 lakes, wetlands and ponds in Southern Sweden. The results show that Asellus pigmentation was correlated with substrate darkness across all localities. In seven localities, in which two contrasting substrate types were noted, Asellus populations were differentiated with respect to pigmentation. These findings thus provide phenomenological support for cryptic pigmentation in Asellus. Pigmentation generally increased with body size, but the relationship between pigmentation and size differed among localities, possibly as a result of differences in correlational selection on pigmentation and size. Selection thus appears to have resulted in local differentiation over a small spatial scale, even within lakes and wetlands. This differentiation is a likely cause behind elevated phenotype variation noted in localities with two substrate types, suggesting that habitat heterogeneity promotes genetic diversity.