SCIENCE:

 


SCIENCE MEETING.

Last month Dr Angela Mallard’s talk reflected on her experience of running the Cornwall prenatal screening programme for Down Syndrome(DS) for almost 30 years. We learnt that John Landon Down who first described the syndrome in 1862 was Cornish.

amnicentesis

 

From the early 1970s, only invasive diagnostic amniocentesis was offered to women who were 35 years or older. The uptake was only 35%, with a detection rate of 30%.

In 1983 it was first noted that maternal blood AFP(alpha- fetoprotein) originating from the fetal liver, was lower and HCG(chorionic gonadotrophin) from the placenta, was higher in cases of DS. When combined with age this gave a detection rate of 60% with a 5% false positive rate(FPR).

Locally, testing began in 1992 and was offered to all women in the second trimester by measuring serum AFP and HCG levels, which with maternal age and ultrasound gestational age are combined in an algorithm to give a risk for DS. Less than 1 in 250 was considered “high risk” and resulted in women being offered amniocentesis, usually after 15 weeks, to confirm the diagnosis by looking for an extra copy of chromosome 21 in fetal cells. In most cases, DS can be excluded, although this procedure has a fetal loss of about 1 in 100. Over 15 years this screening gave a detection rate of 78% for DS cases with 7.6% FPR.

In 2008 most testing moved to the first trimester using the blood markers, free beta HCG and PAPP-A (pregnancy associated placental protein-A). Results are combined with measurement of the nuchal translucency measured by ultrasound at the dating scan. This is the space between the foetal spine and the skin at the back of the neck which is often increased in DS. Other risk factors such as maternal weight, ethnicity, smoking, presence of insulin dependent diabetes are included in this algorithm. Diagnostic testing at this stage is by chorionic villus sampling in which a small sample of the placenta is taken from about the 10th week of pregnancy. Auditing results over 9 years showed that the detection rate had increased to 87% with only a 2.1% FPR.

2016 saw the introduction of NIPT(non-invasive prenatal testing) in which cell-free fetal DNA is measured in maternal blood by polymerase chain reaction(PCR). Since 2020 it is now available on the NHS and has led to large reduction in invasive testing.

The last part of the talk covered the quality standards that laboratories now have to strictly follow to ensure that accurate and reliable testing occurs across the UK. One of these mentioned a need for a laboratory to analyse at least 8000 samples annually. This has resulted after Angela’s retirement in 2017 in the service being transferred to Exeter.

On 9th December we have rearranged for Cheryl Marriott, Head of Conservation at the Cornwall Wildlife Trust, to talk about the Cornwall Beaver Project.

Whilst it is was ‘just a pair of beavers’ released into a 5 acre enclosure back in 2017, its success is a cause for optimism in terms of tackling the joint problems of biodiversity crisis and climate emergency. Cheryl will explain what it is about these animals that has captured people’s imagination; and how the site and the stream have changed beyond recognition over the last 4 years.


Roy Fisher              01872 270528                  raf59@talktalk.net

Psychology

HUMAN PSYCHOLOGY

We are meeting again on the first Wednesday in the month.
HUMAN PSYCHOLOGY

We’ve been speculating about the way humanity’s insatiable desire to “progress” (as illustrated below) seems to have affected, not only our natural environment, but our psychological make-up and personal feelings of well-being and happiness too.

psychology

 

The people of Bhutan felt the concept of ‘progress’ ought to be considered in terms of ‘gross national happiness’ but the capitalist economies of the world think it should be measured in terms of ‘gross national product’, ‘employment-levels’, ‘per capita income’, and so on.  Perhaps therefore, our sensually-conscious feelings, and our conceptually-conscious thoughts, point us in different directions and may even be in denial of each other, sometimes resulting in stress-related illnesses such as bipolar disorder, and schizophrenia which has been described as “a consequence of modernity” [Al-Khalili, 2014].  So, how has this change in our different levels of consciousness, and in the way we evaluate our own and everyone else’s sense of well-being, come about? 
As a social-species, our sensually-conscious need to care and share things cooperatively together and, where necessary, to restrain conflict by means of reconciliation, has gradually been replaced by the conceptually-conscious belief that, to progress, we now need to compete against one another instead.  It has come about by an overall change in the way communities everywhere use to control themselves equilaterally and in balance, to the way we now find ourselves being controlled and organized hierarchically out of balance, in order to achieve our dreams of the future.  Yet, “it’s a remarkable paradox, that at the pinnacle of human material and technical achievement, we find ourselves anxiety-ridden, prone to depression, worried about how others see us, unsure of our friendships, driven to consume and with little or no community life” [Wilkinson & Picket, 2010]. 
Perhaps there’s scope here for further discussion at our next meeting about the real meaning of ‘progress’ and of our ‘well-being’?

John Faupel: johnfaupel@btinternet.com, 01872-561628


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For all activities, please check our Google Calendar to confirm dates, times and locations

Pat Harrod Groups coordinator