Daily Archives: January 29, 2017

PART and the Amyloid Cascade Hypothesis

Stylised Diagram of the Hippocampus - Frank Gaillard

Diagram showing Hippocampus, an area affected by Alzheimer’s Disease (credits Appendix A)

Pathologist and Associate Professor John Crary has written an interesting piece on PART and the relationship to the Amyloid Cascade Hypothesis. PART is an acronym for Primary Age Related Tauopathy. Whilst the Amyloid Cascade Hypothesis has a great deal of supporting evidence there is data which contradicts the hypothesis.

Professor Crary references pathological findings where people with clinically diagnosed Alzheimer’s Type Dementia are found to lack evidence of Amyloid toxicity but there is the presence of tangles. He hypothesises that PART, if it is a valid construct reflects an aging mechanism in the brain independent of Amyloid plaque. He also cites evidence that the pathology is found in areas including the medial temporal lobe structures that are likely to be exposed to mechanical injury during the lifespan.

Appendix A – Credits

Picture by FG Designs. Creative Commons License.

Appendix B – Summary of the Amyloid Cascade Hypothesis

For further details see here

(1) Amyloid is central to all pathophysiological processes that lead to Alzheimer’s Disease
(2) Amyloid (including the ABeta components) is toxic
(3) An increase in Amyloid through increased production, reduced removal or both leads to increased toxicity
(4) Amyloid/ABeta leads to tangle pathophysiology
(5) Tangle pathophysiology leads to neuronal cell death
(6) Reducing Amyloid/A Beta would improve symptoms resulting from the Alzheimer’s Disease process

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

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Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

The Origins of the International Classification of Diseases

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In this series, we have been looking at health information exchanges, interfaces that allow medical information to follow a person between organisations and different clinical informatics systems. Along the way we have seen that the exchange of information is facilitated by using standardised frameworks for recording clinical information. This bifurcates into the classification of diseases on one hand (e.g the International Classification of Diseases) and a database driven clinical ontology on the other hand (e.g SNOMED-CT ®). We have seen that SNOMED began as SNOP in 1965 and then developed into SNOMED-RT before merging with the UK Read codes to form SNOMED-CT ®.

The development of SNOMED is a little complex but what about the World Health Organisation’s International Classification of Diseases (ICD)? Where did that begin? Well a brief and very helpful overview of the development of ICD can be found on the WHO website. Although there had been a number of classification systems developed in the 19th and 18th centuries, ICD began as a classification of deaths.

The International Statistical Institute established a committee to draw up a classification of the causes of death. Jacques Bertillon was the central figure in these efforts and was the chair of the committee drawing up the classification. Interestingly enough Bertillon’s brother Alphonse Bertillon worked in law enforcement in Paris and established the use of biometrics and the mugshot. Bertillon’s grandfather Achille Guillard was a statistician who had coined the term demographics and requested a resolution for a ‘uniform classification’ in the first Statistical Congress in 1853.

The Bertillon Classification of Causes of Death was in essence the first version of the International Classification of Disease but of course had a different meaning. ICD editions are referred to as revisions – they are revisions of this original classification of causes of deaths. Bertillon’s classification was presented and adopted at the meeting of the International Statistical Institute in 1893.

Appendix A – Other Posts in the Series on Health Information Exchanges

A Literature Review of 40 years of SNOMED

Arizona Statewide Health Information Exchange

A History of The Health Information Exchange in Pennsylvania

The Arkansas Health Information Exchange – SHARE

The California Health Information Exchange – Cal Index

Creating a Health Information Exchange in Arizona

Health Information Exchanges

Health Information Exchanges and Chronic Conditions

HIPPA and Health Information Exchanges

ICD-11 and SNOMED CT®

ICD-SNOMED-CT® Harmonisation

Körner Data and SNOMED: A Snapshot from 1988

Mapping ICD 9 (or 10) to SNOMED CT®

Over 1 Million Relationships: SNOMED CT ®

Standardisation of Health Information Technology in New Zealand

Why Do We Need Electronic Record Systems to Talk to Each Other

Appendix B – Definition of Health Information Exchange

This is the definition of the Health Information Exchange that I use (Hersh et al, 2015)

Health information exchange (HIE), the electronic sharing of clinical information across the boundaries of health care organizations

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section.