In the News Round-Up this week, there is an accompanying video presentation. Research includes the finding of an association between late-life depression and reduction in pyramidal cell volume in layer 5 throughout the cortex, further evidence for the importance of hippocampal volume in conversion from Mild Cognitive Impairment to Alzheimer’s Disease, an intriguing finding that there appears to be a more highly structured connectivity between brain regions in Frontotemporal dementia according to evidence from an EEG study, a relationship between the MECP-2 gene region and brain structure and an alteration in the Arcuate Fasciculus in people who are tone-deaf.
The authors of a systematic review looked at services providing acute time-limited residential alternatives to inpatient psychiatric ward treatment for people needing acute admission. The authors described their search strategy and were able to identify 27 studies for inclusion in their review. They assessed the quality of these studies and found that a number of the studies didn’t conceal allocation of subjects or adjust for confounders although they did provide evidence of outcomes comparable to acute inpatient treatment in a number of studies. The authors concluded that more research was needed in this area although there was ‘preliminary evidence’ to support the community-based alternatives examined* (Lloyd-Evans et al, 2009).
Research in Mood Disorders
A post-mortem study (n=27) compared 17 people who had developed late-life depression with 10 controls and the researchers found a significant reduction in the volume of the pyramidal cells (to a greater extent in layer 5) throughout the cortex in the depression group. Interestingly the layer 5 cells are more susceptible to ischaemic damage which has also been noted to be more prevalent in people with late-life depression suggesting a possible hypothesis which could be explored in future studies (Khundakar et al, 2009).
Research in Dementia
In a post-mortem study there was found to be a case of Alzheimer’s Disease without uptake of radiolabelled Pittsburgh compound B (PIB) and the authors suggest that this compound might bind differentially to various forms of multimeric ABeta. The implication if this holds is that a PIB negative finding might not always exclude the diagnose of Alzheimer’s Disease. However as this is a single case, it will be interesting to see if these results are replicated (Rosen et al, 2009). The authors of an imaging study (n=comparing people with Alzheimer’s Disease or Mild Cognitive Impairment with healthy control used a ligand for the Alpha4Beta2 nicotinic acetylcholine receptor and found no significant difference between the groups after controlling for multiple confounders before concluding that this supported the hypothesis that aceytlcholine reductions are observed late in Alzheimer’s Disease (Mitsis et al, 2009).
News In Brief
The authors of one paper examine the hypothesis that the Raphe nuclei might be an important component of the pathology of Alzheimer’s Disease (Simic et al, 2009). Further evidence for a link between Frontotemporal Dementia and Amyotrophic Lateral Sclerosis (ALS) has been found in a post-mortem study where the FUS (fused in sarcoma) protein (associated with ALS) was found in the neuronal inclusions in 15 people with frontotemporal dementia (Neumann et al, 2009). An analysis of the data from the Alzheimer’s Disease Neuroimaging Initiative provides further support for the hypothesis that conversion from Mild Cognitive Impairment to Alzheimer’s Disease is strongly influenced by Medial Temporal Lobe volume and particularly the volume of the hippocampus (Risacher et al, 2009). A small study involving 34 people without evidence of cognitive impairment, at post-mortem found a significant correlation between performance on a smell test (the Brief Smell Identification Test) and Alzheimer’s Disease pathology (Wilson et al, 2009). The smell test however can be influenced by smoking.
Using an analysis of EEG data from patients with Frontotemporal Lobar Degeneration and Alzheimer’s Disease, a team has found further evidence that in Alzheimer’s Disease there is increasing disconnection between areas in the brain. However they found that communication between areas became more structured in people with FTLD. The findings are relevant in terms of a disconnection hypothesis which maintains that in Alzheimer’s Disease there is a loss of function resulting from impaired communication between brain regions. A research team in Germany have provided evidence of ferritin in neurons in Parkinson’s disease. Iron metabolism has been implicated in the disease process and previous research has identified the ferritin in the glial support cells (see also this article in which the Diamond Light Source Synchrotron is being used to examine iron distribution in Parkinson’s Disease). An Israeli study has provided preliminary evidence for the viability of mesenchymal stem cells (which means there is no need for embryonic cells) in a model of Huntington’s Disease. By ‘labelling’ the cells with iron particles they were able to follow their progress using Magnetic Resonance Imaging and observed them migrating to their destination. It will be interesting to see further use of this neuroimaging technique as well as the work with stem cells. In a study looking at the MECP2 gene (methyl CpG binding protein 2). A mutation in this gene results in Rett Syndrome, a developmental disorder associated with seizures and cognitive impairment. The research team looked at the gene and the surrounding DNA in a total of 940 people who were healthy or who had developed dementia or psychosis. They found that one specific allele of MECP2 was associated with a number of changes in the structure in the brain including a reduction in the surface area. They also found that variations in the surrounding region were associated with structural changes in the brain and this gene region may turn out to have an important developmental role.
In a small (n=48) observational study of patients with breast and prostate cancer there was found to be a significant correlation between radiotherapy-associated fatigue and markers of cytokine activity and it will be interesting to see further studies in this area. In a small study (n=62) smokers were found to have a significantly reduced blood supply to the tongue and smaller flatter fungiform papillae (taste buds). This is also consistent with other research that shows an impaired sense of smell in smokers (see appendix in this article). In another study, researchers found that a phenomenon known as ‘perceptual rivalry’ occurs with the sense of smell. They presented subjects with two competing smells, one for each nostril and the subjects nted an alternation between the experienced smells. Such competition is noted in other sensory systems such as the visual system.
An American study has provided evidence that Alcohol adverts on cable television have a significant correlation with the likelihood of teenager viewing of the cable TV. They found that wine adverts were inversely correlated with an increasing percentage of teenage viewers in the audience but that there was a significant linear correlation with spirits, low-alcohol ‘alco-pop’ drinks and beers. This is interesting in relation to older studies which show that teenagers with ‘media resistance skills‘ in another american study were less likely to drink alcohol. Earlier this year an Australian study provided evidence that adolescents there were seeing more alcohol-related adverts and the authors recommended a move towards regulation of adverts.
In a study that compared people who spoke two languages with those speaking just one, researchers found that when reading cognate words, that is words that are similar in both languages, the bilingual subjects took less time to read these words suggesting that learning a second language influenced the way the primary language is processed. A diffuse tensor imaging study (n=20) provided evidence of structural abnormalities in the arcuate fasciculus in people who are tone deaf (half of the subjects were tone deaf). The researchers found that they could not identify the arcuate fasciculus in the right hemisphere. The arcuate fasciculus is a connection between the frontal and temporal lobes. A recent study has demonstrated that ultrasound guided with the aid of Magnetic Resonance Imaging was successfully in ablating tissue in the thalamus in people with neuropathic pain and it will be interesting to follow subsequent research in this area.
There has also been some recent research on Twitter that shows that just over 40% of the postings contain information about the minute-to-minute actions of the twitterers although just under 40% of postings were conversational. CNN have some discussion about this and also a look at social media platforms in general and for those interested there is a link below.
* It is interesting to note the differences in the evidence base between service models and individual pharmaceutical agents. Both have a potential impact on large numbers of people and yet considerable resources are invested into obtaining the evidence in the latter compared to the former.
Brynmor Lloyd-Evans, Mike Slade, Dorota Jagielska and Sonia Johnson. Residential alternatives to acute psychiatric hospital admission: systematic review. The British Journal of Psychiatry. 2009. 195. 109-117.
Khundakar A, Morris C, Oakley A, McKeenin W and Thomas A. Morphometric analysis of neuronal and glial cell pathology in the dorsolateral prefrontal cortex in late-life depression. The British Journal of Psychiatry. 2009. 194. 163-169.
Mitsis EM, Reech KM, Bois F, Tamagnan GD, Macavoy MG, Seibyl JP, Staley JK, van Dyck CH. 123I-5-IA-85380 SPECT Imaging of Nicotinic Receptors in Alzheimer Disease and Mild Cognitive Impairment. J Nucl Med. 2009 Aug 18. [Epub ahead of print].
Neumann M, Rademakers R, Roeber S, Baker M, Kretzschmar HA, Mackenzie IR. Brain. 2009 Aug 11. [Epub ahead of print]. Frontotemporal lobar degeneration with FUS pathology.
Risacher SL, Saykin AJ, West JD, Shen L, Firpi HA, McDonald BC; Alzheimer’s Disease Neuroimaging Initiative (ADNI).Curr Alzheimer Res. 2009 Aug;6(4):347-61.Baseline MRI predictors of conversion from MCI to probable AD in the ADNI cohort.
Rosen RF, Ciliax BJ, Wingo TS, Gearing M, Dooyema J, Lah JJ, Ghiso JA, Levine H 3rd, Walker LC. Deficient high-affinity binding of Pittsburgh compound B in a case of Alzheimer’s disease. Acta Neuropathol. 2009 Aug 19. [Epub ahead of print]
Simic G, Stanić G, Mladinov M, Jovanov-Milosevic N, Kostovic I, Hof PR.Neuropathol Appl Neurobiol. 2009 Aug 4. [Epub ahead of print] Annotation – Does Alzheimer’s disease begin in the brainstem?
Wilson RS, Arnold SE, Schneider JA, Boyle PA, Buchman AS, Bennett DA.Olfactory impairment in presymptomatic Alzheimer’s disease.Ann N Y Acad Sci. 2009 Jul;1170:730-5.
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