Isolation of retinal progenitor and stem cells from the porcine eye

Purpose: Retinal progenitor cells (RPCs) and retinal stem cells (RSCs) from rodents and humans have been isolated and characterized in vitro. Transplantation experiments have confirmed their potential as tools for cell replacement in retinal degenerative diseases. The pig represents an ideal pre-clinical animal model to study the impact of transplantation because of the similarity of its eye to the human eye. However, little is known about porcine RPCs and RSCs. We aimed to identify and characterize in vitro RPCs and RSCs from porcine ocular tissues. Methods: Cells from different subregions of embryonic, postnatal and adult porcine eyes were grown in suspension sphere culture in serum-free medium containing basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Growth curves and BrdU incorporation assays were performed to establish the proliferative capacity of isolated porcine retina-derived RPCs and ciliary epithelium (CE)-derived RSCs. Self-renewal potential was investigated by subsphere formation assays. Changes in gene expression were assayed by reverse transcription polymerase chain reaction (RT-PCR) at different passages in culture. Finally, differentiation was induced by addition of serum to the cultures and expression of markers for retinal cell types was detected by immunohistochemical staining with specific antibodies. Results: Dissociated cells from embryonic retina and CE at different postnatal ages generated primary nestin- and Pax6-immunoreactive neurosphere colonies in vitro in numbers that decreased with age. Embryonic and postnatal retina-derived RPCs and young CE-derived RSCs displayed self-renewal capacity, generating secondary neurosphere colonies. However, their self-renewal and proliferation capacity gradually decreased and they became more committed to differentiated states with subsequent passages. The expansion capacity of RPCs and RSCs was higher when they were maintained in monolayer culture. Porcine RPCs and RSCs could be induced to differentiate in vitro to express markers of retinal neurons and glia. Conclusions: Porcine retina and CE contain RPCs and RSCs which are undifferentiated, self-renewing and multipotent and which show characteristics similar to their human counterparts. Therefore, the pig could be a useful source of cells to further investigate the cell biology of RPCs and RSCs and it could be used as a non-primate large animal model for pre-clinical studies on stem cell-based approaches to regenerative medicine in the retina.

The Cost of Drug Use in Adolescence: Young People, Money and Substance Abuse.

It is now common for young people in full-time compulsory education to hold part-time jobs. However, whilst the 1990s experienced a rise in illicit drug use particularly among young people and an increase in the level of interest for identifying factors associated with drug use, little attention has been paid to the influence of the money young people have to spend and its potential links with drug use. Four thousand five hundred and twenty-four young people living in Northern Ireland completed a questionnaire in school year 10 (aged 13/14 years). The findings suggested there was a positive association between the amount of money (and its source) young people received and higher rates of drug use. The study concludes that money, and how it is spent by young people, may be an important factor for consideration when investigating drug use during adolescence. The findings may help inform drug prevention strategies particularly through advice on money management, and taking responsibility for their own money.

A simplified protocol for routine total DNA isolation from salmonid fishes

An efficient total DNA isolation protocol, suitable for routine population genetic screening purposes is described. This phenol based extraction can utilize fresh, frozen or ethanol preserved tissues.

Drug use amongst young people attending emotional and behavioural difficulty units during adolescence: A longitudinal anlaysis

This paper reports on the findings from a longitudinal survey of the drug use behaviours of young people who were attending Emotional and Behavioural Difficulty (EBD) units from the age of 11-16 years. It forms part of the Belfast Youth Development Study, a longitudinal study of adolescent drug use. This paper presents a follow-up report to a cross-sectional paper that reported on drug use behaviours of a sample of young people attending EBD units when aged 12/13 years at school year 9 (McCrystal et al 2005a). In the present paper reported drug use and behaviours associated with increased risk of its use between the ages of 11-16 years were examined. The findings show that those attending EBD Units consistently reported higher levels of licit and illicit drug use throughout adolescence. Compared with young people in mainstream school, higher levels of behaviours associated with drug use including antisocial behaviour, disaffection with school, and poor communication with their parents/guardians were noted. These findings have implications for the development and timing of targeted prevention initiatives for young people attending EBD units at all stages of adolescent development.

Biosensing and drug delivery by polypyrrole

Conducting polypyrrole is a biological compatible polymer matrix wherein number of drugs and enzymes can be incorporated by way of doping. The polypyrrole, which is obtained as freestanding film by electrochemical polymerization, has gained tremendous recognition as sophisticated electronic measuring device in the field of sensors and drug delivery. In drug delivery the reversing of the potential 100% of the drug can be released and is highly efficient as a biosensor in presence of an enzyme. In this review we discuss the applications of conducting polypyrrole as biosensor for some biomolecules and drug delivery systems.