Archive for July 16th, 2010

Meditation and attention

Buddhist meditation can help people to be more attentive. Katherine MacLean, a graduate student from the University of California, Davis studied 60 people who were already involved in meditation. Half of them studied meditation for three months at a retreat in Colorado while the other half went onto a waiting list for the retreat. During the retreat the participants took a test on a computer where they had to identify the occasional shorter line displayed on the screen after a series of other ones which were of the same length. The participants who were practising meditation at the retreat got better as time went on whereas those on the waiting list stayed the same.

You can find out more about this study by clicking on the title of this post.

Surviving stress in Sri Lanka

Children in Sri Lanka have been exposed to a lot of stress over the last few years with the tsunami of 2004 being followed by a civil war between the Buddhist Sinhalese in the south and the Muslim Tamils in the North. Two recent studies have looked into the psychological effects of this. In the first study researchers from California State University in Los Angeles, Harvard School of Public Health and Claremont Graduate University studied more than 400 people, aged between 11 and 20, who had survived the tsunami. They found that while the children had been affected by the tsunami and the war more ‘everyday’ sources of stress such as poverty, family violence and a lack of safe housing also had an effect. Another study carried out by researchers from Bielefeld University in Germany looked at 1,400 Tamil children aged between 9 and 15 living at home or in a temporary shelter for refugees. 80% of the children had been directly affected by the wave and between 60-90% also reported war-related experiences such as bombings or seeing dead bodies. The study found that all the adverse experiences had an effect on the children with very severe exposure to trauma, loss of family members and domestic violence being particularly stressful.

You can find out more about this research by clicking on the link in the title of the post.

Insulin and Alzheimer’s

People with Alzheimer’s disease could be helped by squirting insulin up their nose. Insulin is important for communication between brain cells and is needed for brain function but several studies have shown that people with Alzheimer’s have reduced levels of it in their brain. Researchers from the University of Washington in Seattle studied 109 people who had Alzheimer’s disease or mild cognitive impairment which can develop into the condition; none of the participants had diabetes. A third of the patients received a placebo, a third a lower dose of insulin and a third a higher dose; all the participants used a nebulizer which they squirted up their nose twice a day for four months. The patients who got the lower dose of insulin showed significant improvements in their thinking, memory and ability to do daily activities.

You can find out more about this research by clicking on the link in the title of this post.

Acids Associated With Atherosclerosis

Studies around the world have consistently shown that both short and long term exposures to Particulate Matter (PM) air pollution are associated with a host of cardiovascular diseases, including myocardial ischemia and infarctions, heart failure, arrhythmias, strokes and increased cardiovascular mortality.

Very recently it was published a study in humans confirming the association of the exposure to ambient air pollution and atherosclerosis through the progression of carotid artery intima-media thickness (1).

In an interesting recent paper by Robert Brook (2) he states that there are three putative ‘general’ pathways to explain the biological mechanisms whereby PM exposure may be capable of mediating cardiovascular events: 1) autonomic mechanisms: parasympathetic nervous system withdraw and/or sympathetic nervous system activation; 2) the release of circulating pro-oxidative and/or pro-inflammatory mediators from the lungs (e. g. cytokines and activated immune cells) into the systemic circulation following PM inhalation that, in turn, indirectly mediate CV responses; and; 3) nano-scale particles and/or soluble PM constituents translocating into the systemic circulation after inhalation that then directly interact with the CV system.

According to Robert Brook, chronic actions of PM and the enhancement of atherosclerosis, are most likely to be induced by the generation of a chronic pro-inflammatory state (pathway 2).

Taking in view the results of studies in humans showing that particulate air pollutants continuous exposition decreases the heart rate variability (3,4) and may lead to an impaired autonomic control with potential acceleration in the progression of atherosclerosis (5,6,7), with the due respect, I feel obliged to differ from Brook’s opinion regarding the biological mechanism related to chronic PM exposure and atherosclerosis. In our view the sympathetic over activity may start the whole process of atherosclerosis which ends in the inflammatory state as hypothesized in the acidity theory of atherosclerosis (8) and discussed in our last article in this blog (9)Carlos Monteiro

1. Nino Kunzli, Michael Jerrett, Raquel Garcia-Esteban, Xavier Basagana, Bernardo Beckermann, Frank Gilliland, Merce Medina, John Peters, Howard N. Hodis, Wendy J. Mack. “Ambient Air Pollution and the Progression of Atherosclerosis in Adults.” PloS ONE 5(2): e9096. doi:10.1371/journal.pone.0009096, February 8, 2010. Full free text at http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0009096

2. Brook RD, Cardiovascular effects of air pollution. Clinical Science (2008) 115, (175–187) Full free text at http://www.clinsci.org/cs/115/0175/1150175.pdf

3. Duanping Liao, Yinkang Duan, Eric A. Whitsel, Zhi-jie Zheng, Gerardo Heiss, Vernon M. Chinchilli, and Hung-Mo Lin. Association of Higher Levels of Ambient Criteria Pollutants with Impaired Cardiac Autonomic Control: A Population-based Study, Am J Epidemiol 2004;159:768–777

4. C. Arden Pope III, Matthew L. Hansen, Russell W. Long, Karen R. Nielsen, Norman L. Eatough, William E. Wilson, and Delbert J. Eatough. Ambient Particulate Air Pollution, Heart Rate Variability, and Blood Markers of Inflammation in a Panel of Elderly Subjects. Environmental Health Perspectives, V 112; N 3: March 2004

5. Heikki V. Huikuri; Vesa Jokinen; Mikko Syvänne; Markku S. Nieminen; K. E. Juhani et al, Heart Rate Variability and Progression of Coronary Atherosclerosis. Arteriosclerosis, Thrombosis, and Vascular Biology. 1999;19:1979-1985.

6. Anders Gottsäter , Åsa Rydén Ahlgren, Soumia Taimour and Göran Sundkvist, Decreased heart rate variability may predict the progression of carotid atherosclerosis in type 2 diabetes Clinical Autonomic Research Volume 16, Number 3 / June, 2006

7. J. C. Longenecker, M. Zubaid, K.V. Johny, A.I. Attia, J. Ali, W. Rashed, C.G. Suresh, M. Omar. Association of low heart rate variability with atherosclerotic cardiovascular disease in hemodialysis patients. Med Princ Pract 2009;18:85-92

8. Carlos ETB Monteiro, Acidic environment evoked by chronic stress: A novel mechanism to explain atherogenesis. Available from Infarct Combat Project, January 28, 2008 at http://www.infarctcombat.org/AcidityTheory.pdf

9. Sympathetic predominance: a primary factor in the cascade of events leading to the atherogenic spiraling, Carlos Monteiro, Monday, February 22, 2010 at http://aciditytheory.blogspot.com/2010/02/sympathetic-predominance-primary-factor.html

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