TGI Friday! Our regular round-up of research abstracts, 27 January 2012

January 27, 2012

Our weekly roundup of research paper abstracts that have not already appeared on the website

Infect Dis Clin North Am.
2011 Dec;25(4):851-63. Epub 2011 Sep 9.

The common immunogenic etiology of chronic fatigue syndrome: from infections to vaccines via adjuvants to the ASIA syndrome.

Rosenblum H, Shoenfeld Y, Amital H.
Department of Medicine B, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel-Hashomer 52621, Israel.


Chronic fatigue syndrome (CFS) is characterized by unexplained fatigue that lasts for at least 6 months with a constellation of other symptoms. Most cases start suddenly, and are usually accompanied by a flu-like illness. It is a symptom-based diagnosis of exclusion, the pathogenesis of which is unknown.

Studies have examined and hypothesized about the possible biomedical and epidemiologic characteristics of the disease, including genetic predisposition, infections, endocrine abnormalities, and immune dysfunction and psychological and psychosocial factors.

Recently, the AISA (autoimmune/inflammatory syndrome induced by adjuvants) syndrome was recognized, indicating the possible contribution of adjuvants and vaccines to the development of autoimmunity.

Infect Dis Clin North Am.
2011 Dec;25(4):851-63. Epub 2011 Sep 9
[Article in English, Portuguese]

Somatization in Latin America: a review of the classification of somatoform disorders, functional syndromes and medically unexplained symptoms.

Tofoli LF, Andrade LH, Fortes S.
Medical School/Post-Graduate Program in Family Health, Universidade Federal do Cearå (UFC), Sobral, CE, Brasil.


OBJECTIVE: hMedically unexplained symptoms are common and associated with mental illness in various contexts. Previous studies show that Latin American populations are prone to somatization. Given the reformulation of the International Classification of Diseases towards its 11th edition the peculiarities of the population from this region of the world shall be taken into consideration. The objective of this study is to provide information on somatization in Latin American populations to help the decision making about medically unexplained symptoms diagnostic categories in the 11th edition of the International Classification of Diseases.

METHOD:Extensive review of the academic production from 1995 to 2011 on somatization in populations of Latin American origin.

RESULTS:The analysis of 106 studies included in this review was divided into 15 categories: systematic reviews, conceptual reviews, prevalence, primary care, depression and anxiety, risk factors, violence, organic conditions, relationship with health care, ethnicity, culture-bound syndromes, chronic fatigue syndrome, fibromyalgia, body dysmorphic disorder, and conversion and dissociation.

CONCLUSION: The Latin American studies confirm the difficulty in defining medically unexplained symptoms categories. The supposed “somatizing trace” of Latin cultures may be linked more to cultural and linguistic expression than to an ethnic nature, and these peculiarities must be on the agenda for the new classification of these phenomena in the Classification of Diseases-11th edition.

2011;64(4):183-94. Epub 2011 Sep 9.

Convergent genomic studies identify association of GRIK2 and NPAS2 with chronic fatigue syndrome.

Smith AK, Fang H, Whistler T, Unger ER, Rajeevan MS.
Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.


BACKGROUND: There is no consistent evidence of specific gene(s) or molecular pathways that contribute to the pathogenesis, therapeutic intervention or diagnosis of chronic fatigue syndrome (CFS). While multiple studies support a role for genetic variation in CFS, genome-wide efforts to identify associated loci remain unexplored. We employed a novel convergent functional genomics approach that incorporates the findings from single-nucleotide polymorphism (SNP) and mRNA expression studies to identify associations between CFS and novel candidate genes for further investigation.

METHODS: We evaluated 116,204 SNPs in 40 CFS and 40 nonfatigued control subjects along with mRNA expression of 20,160 genes in a subset of these subjects (35 CFS subjects and 27 controls) derived from a population-based study.

RESULTS: Sixty-five SNPs were nominally associated with CFS (p<0.001), and 165 genes were differentially expressed (≥-fold; p≤0.05) in peripheral blood mononuclear cells of CFS subjects. Two genes, glutamate receptor, ionotropic, kinase 2 (GRIK2) and neuronal PAS domain protein 2 (NPAS2), were identified by both SNP and gene expression analyses. Subjects with the G allele of rs2247215 (GRIK2) were more likely to have CFS (p=0.0005), and CFS subjects showed decreased GRIK2 expression (10-fold; p=0.015). Subjects with the T allele of rs356653 (NPAS2) were more likely to have CFS (p=0.0007), and NPAS2 expression was increased (10-fold; p=0.027) in those with CFS.CONCLUSION: Using an integrated genomic strategy, this study suggests a possible role for genes involved in glutamatergic neurotransmission and circadian rhythm in CFS and supports further study of novel candidate genes in independent populations of CFS subjects.

J Womens Health (Larchmt)
. 2011 Sep;20(9):1297-306. Epub 2011 Aug 8.

Sex bias in studies selected for clinical guidelines.

Ballantyne AJ, Rogers WA.
Department of Primary Health Care and General Practice, School of Medicine and Health Sciences, Otago University Wellington, Wellington, New Zealand.


OBJECTIVE: To determine the proportions of female participants in research studies selected to inform the development of national clinical guidelines and to assess these against the proportions of women affected by the conditions.

METHODS: We assessed 392 published articles, involving a total of 5.2 million participants, cited as references in five influential clinical guidelines addressing the use of antiarrhythmics, chronic fatigue, depression, diabetes, and colorectal cancer. For each article, we extracted the number of female participants to determine any discrepancies in the sex of participants and if the proportion of female participants as research subjects reflected the sex distribution of patients affected by the condition.

RESULTS: The overall and median percentages (per study) of females per guideline were: use of antiarrhythmics (35%, median 38%), chronic fatigue (70%, median 73%), colorectal cancer (67%, median 46%), depression (66%, median 66%), and diabetes (63%, median 50%). The baseline prevalence rates used for comparison purposes were (percentage female): antiarrhythmics (60% of patients 75(+) years); chronic fatigue (66%), colorectal cancer (46%), depression (66%), and diabetes (46%).

CONCLUSIONS:The colorectal cancer, depression, and chronic fatigue guidelines were based on research populations that accurately reflected the sex distribution of the condition in the general population. Women were slightly overrepresented in the research studies supporting the diabetes guidelines and were significantly underrepresented in the research studies supporting the guidelines on the use of antiarrhythmics. Guideline developers should be aware of and comment on the potential impact of sex. Where the evidence base is lacking, guideline developers should highlight this and, where necessary, limit their specific conclusions to populations on whom the research was performed.

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