Archive for December, 2009

Mutation screen and association studies for the fatty acid amide hydrolase (FAAH) gene and early onset and adult obesity

Thursday, December 31st, 2009

Background:
The orexigenic effects of cannabinoids are limited by activation of the endocannabinoid degrading enzyme fatty acid amide hydrolase (FAAH). The aim of this study was to analyse whether FAAH alleles are associated with early and late onset obesity.
Methods:
We initially assessed association of five single nucleotide polymorphisms (SNPs) in FAAH with early onset extreme obesity in up to 521 German obese children and both parents. SNPs with nominal p-values [less than or equal to] 0.1 were subsequently analysed in 235 independent German obesity families. SNPs associated with childhood obesity (p-values[less than or equal to]0.05) were further analysed in 8,491 adult individuals of a population-based cohort (KORA) for association with adult obesity. One SNP was further analysed in 985 German obese adults and 588 normal and underweight controls. In parallel, we screened the FAAH coding region for novel sequence variants in 92 extremely obese children using single-stranded-conformation-polymorphism-analysis and denaturing HPLC and assessed the implication of the identified new variants for childhood obesity.
Results:
The trio analysis revealed some evidence for an association of three SNPs in FAAH (rs324420, rs324419 and rs873978) with childhood obesity (two-sided p-values between 0.06 and 0.10). Although analyses of these variants in 235 independent obesity families did not result in statistically significant effects (two-sided p-values between 0.14 and 0.75), the combined analysis of all 603 obesity families supported the idea of an association of two SNPs in FAAH (rs324420 and rs2295632) with early onset extreme obesity (p-values between 0.02 and 0.03). No association was, however, found between these variants and adult obesity. The mutation screen revealed four novel variants, which were not associated with early onset obesity (p>0.05).
Conclusions:
As we observed some evidence for an association of the FAAH variants rs2295632, rs324420 with early onset but not adult obesity, we conclude that the FAAH variants analyzed here at least do not seem to play a major role in the etiology of obesity within our samples.

Preoperative scallop-by-scallop assessment of mitral prolapse using 2D-transthoracic echocardiography.

Thursday, December 31st, 2009

Background:
This study was conducted to assess the accuracy of harmonic imaging 2D-transthoracic echocardiography (2D-TTE) segmental analysis compared to surgical findings, in degenerative mitral regurgitation (MR).
Methods:
Seventy-seven consecutive patients with severe degenerative MR were prospectively enrolled. Preoperative 2D-TTE with precise localization of prolapsing or flailing scallops/segments was performed. All patients underwent mitral valve surgical repair. Surgical reports (SR), including valve description, were used as references for comparisons. A postoperative control 2D-TTE was performed.
Results:
Out of 462 scallops/segments studied, surgical inspection identified 102 prolapses or flails (22%), 92 of which had previously been detected by 2D-TTE (90.2% sensitivity, 100% specificity). Agreement between preoperative 2D-TTE segmental analysis and SR was 97.8% (k=0.93; p<0.0001). Sixty-nine out of 77 2D-TTE reports were completely concordant with SR (89.6% diagnostic accuracy). None of the 8 non-concordant 2D-TTE reports were in complete disagreement with SR. P2 scallop was always involved in posterior leaflet prolapse or flail and was described correctly by 2D-TTE in 68 out of 69 patients (98,7% agreement, k=0,93; 98.5% sensitivity). The anterior leaflet was involved in 14 patients (18%); A2 segment was involved in all of those cases and was correctly detected by 2D-TTE in 13 (98,7% agreement, k=0,95; 92,8% sensitivity). Antero-lateral and postero-medial para-commissural prolapse or flail had a lower prevalence (14% and 10% respectively), with 2D-TTE sensitivity respectively of 64% and 50%.
Conclusions:
2D-TTE, performed by an experienced echo-lab, has very good diagnostic accuracy in localizing the scallops/segments involved in degenerative MR, particularly for the middle ones (P2-A2), which represent almost the totality of prolapses. More invasive, time consuming and expensive exams should be reserved to selected cases.KeywordsMitral valve prolapse; Scallop; Mitral regurgitation; Transthoracic echocardiography.

Status of implementation of Framework Convention on Tobacco Control (FCTC) in Ghana: a qualitative study

Thursday, December 31st, 2009

Background:
The Framework Convention on Tobacco Control (FCTC), a World Health Organization treaty, has now been ratified by over 165 countries. However there are concerns that implementing the Articles of the treaty may prove difficult, particularly in the developing world. In this study we have used qualitative methods to explore the extent to which the FCTC has been implemented in Ghana, a developing country that was 39th to ratify the FCTC, and identify barriers to effective FCTC implementation in low income countries.
Methods:
Semi-structured interviews with 20 members of the national steering committee for tobacco control in Ghana, the official multi-disciplinary team with responsibility for tobacco control advocacy and policy formulation, were conducted. The Framework method for analysis and NVivo software were used to identify key issues relating to the awareness of the FCTC and the key challenges and achievements in Ghana to date.
Results:
Interviewees had good knowledge of the content of the FCTC, and reported that although Ghana had no explicitly written policy on tobacco control, the Ministry of Health had issued several tobacco control directives before and since ratification. A national tobacco control bill has been drafted but has not been implemented. Challenges identified included the absence of a legal framework for implementing the FCTC, and a lack of adequate resources and prioritisation of tobacco control efforts, leading to slow implementation of the treaty.
Conclusion:
Whilst Ghana has ratified the FCTC, there is an urgent need for action to pass a national tobacco control bill into law to enable it to implement the treaty, sustain tobacco control efforts and prevent Ghana’s further involvement in the global tobacco epidemic.

Genetic diversity among Plasmodium falciparum field isolates in Pakistan measured with PCR genotyping of the merozoite surface protein 1 and 2

Thursday, December 31st, 2009

Background:
The genetic diversity of Plasmodium falciparum has been extensively studied in various parts of the world. However, limited data are available from Pakistan. This study aimed to establish molecular characterization of P. falciparum field isolates in Pakistan measured with two highly polymorphic genetic markers, i.e. the merozoite surface protein 1 (msp-1) and 2 (msp-2).
Methods:
Between October 2005 and October 2007, 244 blood samples from patients with symptomatic blood-slide confirmed P. falciparum mono-infections attending the Aga Khan University Hospital, Karachi, or its collection units located in Sindh and Baluchistan provinces, Pakistan were collected. The genetic diversity of P. falciparum was analysed by length polymorphism following gel electrophoresis of DNA products from nested polymerase chain reactions (PCR) targeting block 2 of msp-1 and block 3 of msp-2, including their respective allelic families KI, MAD 20, RO33, and FC27, 3D7/IC.
Results:
A total of 238/244 (98%) patients had a positive PCR outcome in at least one genetic marker; the remaining six were excluded from analysis. A majority of patients had monoclonal infections. Only 56/231 (24%) and 51/236 (22%) carried multiple P. falciparum genotypes in msp-1 and msp-2, respectively. The estimated total number of genotypes was 25 msp-1 (12 KI; 8 MAD20; 5 RO33) and 33 msp-2 (14 FC27; 19 3D7/IC).
Conclusions:
This is the first report on molecular characterization of P. falciparum field isolates in Pakistan with regards to multiplicity of infection. The genetic diversity and allelic distribution found in this study is similar to previous reports from India and Southeast Asian countries with low malaria endemicity.

No association of the polymorphisms of the frizzled-related protein gene with peak bone mineral density in Chinese nuclear families

Thursday, December 31st, 2009

Background:
The Wnt/beta-catenin signaling pathway plays an important role in skeletal development. Polymorphisms of frizzled-related protein (FRZB), an antagonist of this pathway, may generate variations in bone mineral density (BMD). In this study, we analyzed the association between FRZB genotypes and peak BMD variation in the spines and hips of two relatively large samples of Chinese female-offspring and male-offspring nuclear families.
Methods:
We recruited 1,260 subjects from 401 female-offspring nuclear families and 1,296 subjects from 427 male-offspring nuclear families and genotyped four tagging single nucleotide polymorphisms (tagSNPs) (rs6433993, rs409238, rs288324, and rs4666865) spanning the entire FRZB gene. The SNPs rs288326 and rs7775, which are associated with hip osteoarthritis, were not selected in this study because of their low minor allele frequencies (MAFs) in Chinese people. The quantitative transmission disequilibrium test (QTDT) was used to analyze the association between each SNP and haplotype with peak BMD in female- and male-offspring nuclear families.
Results:
In the female-offspring nuclear families, we found no evidence of an association between either single SNPs or haplotypes and peak BMD in the spine or hip. In the male-offspring nuclear families, no within-family association was observed for either SNPs or haplotypes, although a significant total association was found between rs4666865 and spine BMD (P=0.0299).
Conclusion:
Our results suggest that natural variation in FRZB is not a major contributor to the observed variability in peak BMD in either Chinese females or males. Because ethnic differences in the FRZB genotypes may exist, other studies in different population are required to confirm such results.