Chemotherapy risks for mouse ovaries
The chemotherapy drug etoposide may have adverse effects on the developing ovaries of female fetuses, according to a study in mouse cells published in the open access journal BMC Cancer. While etoposide has been considered relatively safe for women in the second and third trimesters of pregnancy, information on the long term effects of chemotherapy treatment on the future fertility of female fetuses is limited. The researchers, from the University of Edinburgh, found that exposure of mouse ovaries to etoposide before ovarian follicles had formed caused the death of most germ cells. The few remaining germ cells went on to form unhealthy follicles. Once oocytes were enclosed in follicles, etoposide had no significant adverse effects. The researchers collected fetal and neonatal ovaries from mice and cultured them in the laboratory (in vitro). They then exposed groups of six ovaries each to different doses of etoposide. The doses were considered low relative to those normally administered to patients undergoing chemotherapy. When fetal ovaries were treated with etoposide prior to follicle formation, this resulted in dose-dependent damage. Total follicle numbers declined by either 72% or 90% in response to medium and high doses of etoposide respectively. In neonatal ovaries after follicle formation, etoposide only had minor effects, even at doses higher than those used to treat fetal ovaries. The researchers caution that despite of the value of in vitro methods for preliminary screening, effects observed may not necessarily be observable in living organisms (in vivo). Lead author Norah Spears wrote: “A woman’s reproductive lifespan is determined before birth, while the ovaries are developing in the womb. The second trimester of pregnancy is particularly important as this is when female germ cells form follicles which will determine how many eggs a woman will be able to release in her lifetime. If the results we have seen in these mouse studies are found to be replicated in humans, some of that germ cell supply would be lost, which could later result in early menopause, thus reducing the woman’s fertility window.”
Virtual reality helps patients with paraplegia move again
A study published in Scientific Reports, involving eight patients with paraplegia with chronic spinal cord injuries (SCIs), found that after 12 months’ training with a non-invasive brain-machine interface (BMI) protocol, all participants experienced improvements in sensations (including pain localisation and fine and crude touch) and voluntary muscle control below the level of the spinal cord lesion. The research suggests that long term training can induce partial neurological recovery below the level of a spinal cord injury in patients with paraplegia. BMIs have emerged as potential options to restore mobility in patients who are severely paralyzed as a result of SCIs or neurodegenerative disorders. However, to date no study has suggested that long term training associating BMI-based paradigms and physical training could trigger neurological recovery. Using a multistage neuro-rehabilitation protocol, the researchers from Duke University, investigated the impact that training could have on the ability to walk autonomously using a brain-controlled exoskeleton in eight participants with SCIs (seven of which were diagnosed with total paralysis below the level of the SCI). The protocol included using a brain-controlled robotic exoskeleton, virtual-reality environments and training on non-invasive brain controlled virtual avatar bodies with visual and tactile feedback. Neurological examinations, carried out after 12 months’ training using the protocol, revealed that all of the participants had experienced a significant clinical improvement in their ability to perceive sensations and exert voluntary motor control in muscles located below the original SCI. The findings suggest that long term exposure to BMI-based protocols may be capable of inducing partial recovery of some neurological functions.
Navigating the human genome with Sequins
Australian genomics researchers have announced the development of Sequins – synthetic “mirror” DNA sequences that reflect the human genome. This intuitive new technology, which can be used to better map and analyse complexity within the genome, is freely available to the academic research community. Scientists at the Garvan Institute of Medical Research have developed the Sequins technology, which is described in two linked studies published in Nature Methods. The researchers came up with the idea of adding Sequins – small stretches of synthetic DNA – to a patient’s DNA sample during sequencing. These Sequins (or sequencing spike-ins) then act as internal standards, helping researchers analyse the large data files that are generated during genome sequencing. When added to a sequencing reaction, Sequins provide internal controls with which to assess the sensitivity and accuracy of genome sequencing. Because Sequins are added to each individual sample, they can provide a sample-by-sample assessment – something that has not previously been possible. “The potential applications of Sequins are many, from increasing reliability of diagnostic cancer testing, to allowing comparisons of genomic data from institutions worldwide,” the researchers say. Because all genomes, from bacteria to human, have handedness, Sequins can be similarly designed for any organism, or for almost any next-generation sequencing application. Sequins can be requested for use in your own research at http://www.sequin.xyz/.
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