CRITICAL APPRAISAL
Download
1 / 32

CRITICAL APPRAISAL Bob Lightowlers Mitochondrial Research Group Institute of Neuroscience - PowerPoint PPT Presentation


  • 64 Views
  • Uploaded on

CRITICAL APPRAISAL Bob Lightowlers Mitochondrial Research Group Institute of Neuroscience. NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!!. NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!! ONLY 15% OF PUBLICATIONS ARE TRUSTWORTHY. NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!!

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' CRITICAL APPRAISAL Bob Lightowlers Mitochondrial Research Group Institute of Neuroscience' - jaimie


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

CRITICAL APPRAISAL

Bob Lightowlers

Mitochondrial Research Group

Institute of Neuroscience



NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!!

ONLY 15% OF PUBLICATIONS ARE TRUSTWORTHY


NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!!

ONLY 15% OF PUBLICATIONS ARE TRUSTWORTHY

GUILTY UNTIL PROVEN INNOCENT


Mutations in mitochondrial cytochrome c oxidase

genes segregate with late-onset Alzheimer Disease


Hypothesis:

Alzheimers Disease could be caused by defects in activity

of the respiratory chain complex cytochrome c oxidase


Why ?

  • Lack of FH is a negative risk factor


Why ?

  • Lack of FH is a negative risk factor

  • Risk of AD increases with affected maternal relative (mtDNA?)


Human mtDNA

  • An autosomally replicating genome

  • Found in mitochondrial matrix

  • Circular genome with short (1.2knt)

  • noncoding region (D-loop)

16,569 bp

  • Comprises app. 0.1% of total cell DNA

  • Varies enormously in copy number/cell

  • Approx. 700 in fibroblasts to >200,000

  • in some mammalian oocytes

  • Maternally inherited

  • Often heteroplasmic in the diseased state


Why ?

  • Lack of FH is a negative risk factor

  • Risk of AD increases with affected maternal relative (mtDNA?)

  • Mutations in mtDNA can lead to defective OXPHOS


Why ?

  • Lack of FH is a negative risk factor

  • Risk of AD increases with affected maternal relative (mtDNA?)

  • Mutations in mtDNA can lead to defective OXPHOS

  • Neurons may be particularly susceptible to such defects


Why ?

  • Lack of FH is a negative risk factor

  • Risk of AD increases with affected maternal relative (mtDNA?)

  • Mutations in mtDNA can lead to defective OXPHOS

  • Neurons may be particularly susceptible to such defects

  • COX activity reported to decrease in brain of AD patients


Methods used

  • MtDNA isolation and sequencing in patients,

  • asymptomatic relatives and controls


Methods used

  • MtDNA isolation and sequencing in patients,

  • asymptomatic relatives and controls

  • All three COX genes sequenced


Methods used

  • MtDNA isolation and sequencing in patients,

  • asymptomatic relatives and controls

  • All three COX genes sequenced

  • Quantification of mutations in all samples


Methods used

  • MtDNA isolation and sequencing in patients,

  • asymptomatic relatives and controls

  • All three COX genes sequenced

  • Quantification of mutations in all samples

  • Platelet fusion from AD patients to neuronal cells

  • lacking mtDNA (rho0)


Biopsy

EthBr

Enucleation

Generation of transmitochondrial

cybrids


Methods used

  • MtDNA isolation and sequencing in patients,

  • asymptomatic relatives and controls

  • All three COX genes sequenced

  • Quantification of mutations in all samples

  • Platelet fusion from AD patients to neuronal cells

  • lacking mtDNA (rho0)

  • Analysis of respiratory enzyme activity in the cybrids


Methods used

  • MtDNA isolation and sequencing in patients,

  • asymptomatic relatives and controls

  • All three COX genes sequenced

  • Quantification of mutations in all samples

  • Platelet fusion from AD patients to neuronal cells

  • lacking mtDNA (rho0)

  • Analysis of respiratory enzyme activity in the cybrids

  • Analysis of ROS production in cybrids


Results

506 Patients and 95 controls


Results

506 Patients and 95 controls

10 clones of all three COX genes sequence


Results

506 Patients and 95 controls

10 clones of all three COX genes sequence

6 mutations found in COI and COII


Results

506 Patients and 95 controls

10 clones of all three COX genes sequence

6 mutations found in COI and COII

Different levels of heteroplasmy but levels significantly

greater in the AD cohort


Results

506 Patients and 95 controls

10 clones of all three COX genes sequence

6 mutations found in COI and COII

Different levels of heteroplasmy but levels significantly

greater in the AD cohort

No disease-associated mutations in COIII gene


Results

506 Patients and 95 controls

10 clones of all three COX genes sequence

6 mutations found in COI and COII

Different levels of heteroplasmy but levels significantly

greater in the AD cohort

No disease-associated mutations in COIII gene

AD cybrids but not controls had low COX activity


Results

506 Patients and 95 controls

10 clones of all three COX genes sequence

6 mutations found in COI and COII

Different levels of heteroplasmy but levels significantly

greater in the AD cohort

No disease-associated mutations in COIII gene

AD cybrids but not controls had low COX activity

Increased production of ROS in AD cybrids


Critical evaluation:

How appropriate and robust are the methods ?

Is the data (and evaluation) robust ?

Are the conclusions valid, based on the reported data ?

How often do the authors refer to themselves ?

How does the paper stand the test of time ?

Is there any conflict of interest ?


ad