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Detecting Down’s syndrome in the unborn fetus
Down's syndrome is the condition that is screened for the most in pregnant women because of the increased risk with the increasing age of mothers. This unit describes several bioanalytical tests, and how these are used in conjunction with scans to screen and diagnose the condition. First published on Fri, 20 Jul 2012 as
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Acknowledgements

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5.4 The medical chemistry strategy

The strategy adopted was to start from first principles. Since prazosin is an alpha1 antagonist, it must compete with the agonist, noradrenaline, for the alpha1 receptor. So the Pfizer scientists decided to compare the structures of the two molecules and look for common structural features that might provide an insight into the way in which they bind to the receptor. One important observation was the fact that, at physiological pH, both compounds would be protonated, nor
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5.2 The pharmaceutical background

The existence of alpha receptors had been known for many years, and the obvious approach of trying to block these receptors, and hence prevent the noradrenaline from binding, had already been tried by many research groups. A number of compounds with alpha-blocking activity had been identified, including one called prazosin (2) discovered by Pfizer at their US research laboratories in Groton. Substances such as prazosin which block agonist action are called antagonists.


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4 Summary of video

At the beginning of the video clip, Dr Simon Campbell pointed out that, in the development of any drug, there are a number of criteria that must be satisfied. There must be a clinical need – a medical condition or disease that requires effective treatment. Secondly, there has to be a commercial opportunity; because drug development is so expensive, pharmaceutical companies are less likely to invest resources in developing new therapeutic agents where there is already an adequate range of su
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3 Reading activity

You will shortly be asked to read through a research paper published in the Journal of Medicinal Chemistry, in which the synthesis and structure–activity relationships of doxazosin and related compounds are described. It has been provided:
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2 Video activity

The video clip included in this section looks at the development of one particular drug. It examines the complex multidisciplinary process that was involved in its discovery. Before you watch the video, read through the Pre-viewing notes.


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1 The chemical industry

The chemical industry is one of the major contributors to the economies of advanced industrial nations.

The importance of organic chemistry in the pharmaceutical industry becomes apparent in the light of the fact that in the UK alone some £2.2b was spent in 1997 on research and development. Literally thousands of different compounds have to be synthesised and tested in the search for the one that will prove to be a successful and valuable therapeutic agent. As a result, the average cos
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Introduction

This unit examines how organic chemistry is used within the pharmaceutical industry to develop new drugs. You will investigate the process of drug development by following one new product through the intial process and research programme.

This unit is from our archive and it is an adapted extract from Organic chemistry: A synthesis approach (S344) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer
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2.14 Summing up

Activity 13

0 hours 5 minutes

Dr. Peterson concludes the audio sequence with a summary of all the points covered.

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2.12 Translating a cladogram into a classification

Activity 11

0 hours 10 minutes

This clip begins with a diagram by Ernst Haeckel published in 1866 (Figure 11). This is an illustration of how little ideas on the relationships of higher primates have
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2.11 Consequences of human / chimp pairing

Activity 10

0 hours 10 minutes

This clip refers back to the table of molecular characters, which is shown again here (Figure 9). It explains the consequences of human / chimp pairing in terms of homol
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2.10 Chimps, gorillas and humans

Activity 9

0 hours 10 minutes

Dr. Patterson uses a diagram showing alternative cladograms for humans, chimpanzees and gorillas (Figure 10) to summarise evidence supporting the hypothesis that chimps a
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2.9 Conflicting morphological characters

Activity 8

0 hours 10 minutes

This clip looks at conflicting morphological characters and at how it is possible to resolve them, with the aid of a table of molecular characters (Figure 9).

Dr
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2.7 Inferring relationships of common ancestry

Activity 6

0 hours 10 minutes

This clip addresses the question of how one might go about building a tree, or inferring relationships of common ancestry, by recognising evolutionary novelties, or share
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2.6 Three schools of classification

Activity 5

0 hours 10 minutes

This clip explores the three kinds of relationships that have been explained so far, in terms of the work of Simpson, Mayr and Hennig, which are referred to as Simpsonian
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2.5 What does relationship mean in systematics? W. Hennig

Activity 4

0 hours 5 minutes

In this clip, Dr. Patterson introduces his third systematist, a German entomologist named Willi Hennig. This offers a third meaning of ‘relationship’, which is illustr
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2.4 What does relationship mean in systematics? E. Mayr

Activity 3

0 hours 5 minutes

Dr. Patterson looks at the second of his three systematists, Ernst Mayr. Mayr’s answer to the meaning of ‘relationship’ in systematics comes from the point of view o
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2.3 What does relationship mean in systematics? G.G. Simpson

Activity 2

0 hours 5 minutes

Dr. Patterson continues to look at Simpson’s answer to the meaning of ‘relationship’ in systematics, and illustrates this by referring to a diagrams showing how the
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2.2 Darwin, Linnaeus and Simpson

Activity 1

0 hours 15 minutes

In the first clip, Dr. Colin Patterson introduces and explains Darwin’s ‘tree of life’, image, shown below (Figure 3). This was the only image included in his book,
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