Methodology of the Cardiovascular Health and Age-Related Maculopathy (CHARM) Study

Age-related macular degeneration (AMD) is responsible for the majority of visual impairment in the Western world. Epidemiological studies examining risk factors for AMD are needed to develop strategies for the prevention of blindness from this condition. A number of potentially modifiable risk factors for AMD have been identified; however, only smoking has been a consistent risk factor across the numerous studies. A growing body of evidence suggests that AMD and cardiovascular disease may have common risk factors. The Cardiovascular Health and Age Related Maculopathy (CHARM) Study was established to examine the risk factors for AMD and its progression, in particular risk factors associated with cardiovascular disease. Examining risk factors for prevalent AMD, cases with AMD were compared with age and gender matched controls with no AMD features. For the assessment of AMD progression, the study examined in 2001 and 2002 those participants with early AMD, or age-related maculopathy (ARM), who had undergone baseline examination between 1992 and 1995 and compared the characteristics of those who had progression of AMD with those who did not. The CHARM study involved both ophthalmic and cardiovascular examinations. Standardised clinical eye examination and grading of the macular stereo photographs were used to determine the AMD status and progression. To examine cardiovascular status, carotid artery ultrasound imaging analysis of systemic arterial compliance, augmentation index and pulse wave velocity were performed. The traditional and novel risk factors for CVD such as levels of glucose, cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, fibrinogen, C-reactive protein, immunoglobulins A and M, homocysteine, oxidized LDL and the exposure to the Chlamydia Pneumonia infection were determined. DNA was collected for apolipoprotein E genotyping. The present paper outlines the primary aims of the CHARM study, the methodology involved and the recruitment results.

Adjuvant chemoradiation versus surgery alone for adenocarcinoma of the ampulla of Vater

BACKGROUND AND PURPOSE

To examine the role of adjuvant chemoradiation (CRT) in patients with resected ampullary adenocarcinoma.

MATERIALS AND METHODS

The records of patients who underwent curative surgery for ampullary adenocarcinoma at a single institution between 1992 and 2007 were reviewed. Final analysis included 111 patients, 45% of which also received adjuvant CRT.

RESULTS

Median overall survival (OS) was 36.2 months for all patients. Adverse prognostic factors for OS included T stage (T3/4 vs. T1/T2, p=0.046), node status (positive vs. negative, p<0.001), and histological grade (grade 3 vs. 1/2, p=0.09). Patients receiving CRT were more likely to have advanced T-stage (p=0.001), node positivity (p<0.001), and poor histologic grade (p=0.015). Patients who received CRT were also significantly younger (p=0.001). On univariate analysis, adjuvant CRT failed to result in a significant difference in survival when compared to surgery alone (median OS: 33.4 vs. 36.2 months, p=0.969). Patients with node-positive resections who underwent CRT had a non-significant improvement in survival (median OS: 21.6 vs. 13.0 months, p=0.092). Thirty-three percent of patients developed distant metastasis. Common sites of distant metastasis included liver (23%) and peritoneum (7%).

CONCLUSIONS

Adjuvant chemoradiation following curative resection for ampullary adenocarcinoma did not lead to a statistically significant benefit in overall survival. A significant proportion of patients still developed distant metastatic disease suggesting a need for more effective systemic adjuvant therapy.

An assessment of the costs and benefits of interventions aimed at improving rural community water supplies in developed countries

We report a cost benefit analyses (CBA) for water interventions in rural populations of developed country sub-regions. A Bayesian belief network was used to estimate the cost benefit ratio using Monte Carlo simulation. Where possible we used input data from recently published primary research or systematic reviews. Otherwise variables were derived from previous work in the peer-reviewed or grey literature. For these analyses we considered the situation of people with small and very small community supplies that may not be adequately managed. For the three developed country sub-regions Amr-A (America region A), Eur-A (European region A) and Wpr-A (Western Pacific region A), we estimate the costs of acute diarrhoeal illness associated with small community supplies to be U$4671 million (95% CI 1721-9592), the capital costs of intervention to be USD 13703 million (95% CI 6670-20735), additional annual maintenance to be USD 804 million (95%CI 359-1247) and the CB ratio to be 2.78 (95%CI 0.86-6.5). However, we also estimated the cost of post infectious irritable bowel syndrome (IBS) following drinking water-associated acute gastroenteritis to be USD 11896 million (95%CI 3118-22657). When the benefits of reduced IBS are added to the analysis the CB ratio increases to 9.87 (95%CI 3.34-20.49). The most important driver of uncertainty was the estimate of the cost of illness. However, there are very few good estimates of costs in improving management of small rural supplies in the literature. Investments in drinking-water provision in rural settings are highly cost beneficial in the developed world. In the developed world, the CB ratio is substantially positive especially once the impact of IBS is included.

Arterial stiffness is associated with raised levels of the inflammatory marker erythrocyte sedimentation rate among ischaemic stroke patients

We studied the relationship of arterial stiffness, measured by carotid-femoral pulse wave velocity and inflammation, measured by serum erythrocyte sedimentation rate among 334 ischaemic stroke patients. There was a significant correlation between carotid-femoral pulse wave velocity and erythrocyte sedimentation rate (P = 0.001), a relationship independent of age, hypertension, diabetes and smoking. Arterial stiffness and inflammation are associated among ischaemic stroke patients and are independent of established vascular risk factors.

Characterization of novel mutations in the catalytic domain of the PCSK9 gene

OBJECTIVES

To expand our understanding of the structure and function of proprotein convertase subtilisin/kexin type 9 (PCSK9) by studying how naturally occurring mutations in PCSK9 disrupt the function of PCSK9.

DESIGN

Mutations in PCSK9 were identified by sequencing of DNA from subjects with hypo- or hypercholesterolemia. The effect of the identified mutations on the autocatalytic cleavage and secretion of PCSK9, as well as the effect on PCSK9-mediated degradation of the low density lipoprotein receptors, were determined in HepG2 or HEK293 cells transiently transfected with mutant PCSK9-containing plasmids. The findings were collated to the clinical characteristics of the subjects possessing these mutations, and the phenotypic effects were analysed in terms of available structural data for PCSK9.

RESULTS

Five novel mutations in PCSK9 were identified. Mutation R215H was a gain-of-function mutation which causes hypercholesterolemia. Mutation G236S and N354I were loss-of-function mutations due to failure to exit the endoplasmic reticulum or failure to undergo autocatalytic cleavage, respectively. Mutations A245T and R272Q were most likely normal genetic variants. By comparing the number of patients with gain-of-function mutations in PCSK9 with the number of familial hypercholesterolemia heterozygotes among subjects with hypercholesterolemia, the prevalence of subjects with gain-of-function mutations in PCSK9 in Norway can be estimated to one in 15,000.

CONCLUSION

This study has provided novel information about the structural requirements for the normal function of PCSK9. However, more studies are needed to determine the mechanisms by which gain-of-function mutations in PCSK9 cause hypercholesterolemia.

Profile and associations of central pulse wave velocity and central pulse pressure among ischemic stroke patients

Arterial stiffness, a known risk factor for atherosclerosis, can be measured directly with carotid-femoral pulse wave velocity (CPWV) and indirectly with central pulse pressure (CPP). We aimed to compare central and brachial pulse pressures, and to profile CPWV and CPP among ischemic stroke patients. We studied 198 consecutive prospective ethnic Chinese and South Asian ischemic stroke patients, measuring brachial pressures, central pressures and CPWV under standardized conditions using established methods. The mean CPWV was 11.6 +/- 3.2 m/s and CPP was 64 +/- 28 mmHg. CPP was significantly lower than brachial pulse pressure. CPWV and CPP were both independently associated with older age and hypertension. Among ischemic stroke patients, brachial pulse pressure cannot be used as a surrogate for CPP. Older age and hypertension are associated with arterial stiffening.