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Biomedical subjects

E O'Conner

Publications and source records attributed to E O'Conner.

3 recordsLinked to original sources
PubMed2005

Isatin, an endogenous monoamine oxidase inhibitor, triggers a dose- and time-dependent switch from apoptosis to necrosis in human neuroblastoma cells.

Isatin is an endogenous indole that is increased in stress, inhibits monoamine oxidase (MAO) B and improves bradykinesia and striatal dopamine levels in rat models of Parkinson's disease. Consequently, it has been suggested that isatin might be a possible treatment for Parkinson's disease although little is known about its effects on neural cell growth and survival. The aim of this study was to investigate the survival of dopaminergic human neuroblastoma (SH-SY5Y) cells following treatment with increasing concentrations of isatin. SH-SY5Y cells were exposed to isatin for defined time points, after which cell survival was determined by MTT assay. A combination of Annexin V binding and propidium iodide (PI) exclusion was used to distinguish apoptosis from necrosis in flow cytometry experiments and FACS profiles of permeabilised PI-labelled cells were employed for the assessment of cell cycle distribution. Isatin treatment (1-400 microM) for 24h induced a significant dose-dependent increase in MTT metabolism by SH-SY5Y cells in culture, but this was not due to an increase in cell division. At the higher concentrations (200-400 microm) isatin triggered cell death, although MTT metabolism was still increased in the culture, suggesting that surviving cells were hypermetabolic. Following a longer (48 h) exposure, isatin was found to cause cell death in a dose-dependent manner; at lower concentrations (50 microM), the predominant mode of cell death was apoptosis while at the highest concentration (400 microm) increasing numbers of necrotic cells were also evident. Thus, in dopaminergic SH-SY5Y cells isatin induces cell death in dose- and time-dependent manner. This death occurred as a continuum of survival, apoptosis and necrosis. Our results re-emphasise that caution should be exercised when considering high doses of isatin as a putative anti-Parkinson's disease therapeutic.

Annexin A5↗
PubMedDate not supplied

Alternatives to vaginal intercourse practiced during the fertile time among calendar method users in Ireland.

A pilot study was conducted in Ireland to test the effectiveness of the calendar method of contraception. A conservative rule was used, requiring on average 16 days of abstinence per cycle. Among the 19 couples who entered into the study and were followed for up to seven cycles, there were no pregnancies. Since the length of abstinence was relatively long, we collected data to determine how couples expressed love and affection towards each other during those days when the woman was potentially fertile. We also collected data about barrier method use during the fertile time. We found that almost all couples gave each other hugs and kisses to show affection although couples were taught to abstain from vaginal intercourse during the fertile time. About one-third of the couples avoided genital contact, while about half reported using oral sex and/or frottage (body rubbing). Twice as many men reported using masturbation compared to women, although about half of the couples practiced mutual (partner) masturbation. In addition, about one-fifth of the couples used condoms during the fertile time in some cycles. These findings show that a variety of sexual expressions are used by couples when vaginal intercourse is to be avoided. Knowledge about these alternative sexual expressions may be important for couples who wish to engage in sexual activity and to avoid pregnancy.

Coitus↗