Environmental Genotoxicity Assessment Using Micronucleus (and Nuclear Abnormalities) Test on Intertidal Mussel Perumytilus purpuratus: A Tool for Biomonitoring the Chilean Coast.

The release of pollutants is increasing along the coast of Chile, and the use of biomarkers in biomonitoring programs is essential to assess the early biological effects of marine contamination. The Micronucleus (MN) test was carried out using hemocytes of the mussel Perumytilus purpuratus from two sites in northern-central Chile (La Pampilla and Totoralillo). Nuclear abnormalities were assessed, and high frequencies of micronucleus (10.7-14.4‰) and other abnormalities were found (51.9-76.6‰). These values tended to be higher in La Pampilla, possibly due to the large presence of pollution sources in that site. However, considerably high values were observed in both sites. P. purpuratus is a suitable bioindicator and further monitoring along the Chilean coast using this species should be developed using the MN test and/or other biomarkers to comprehend the effects of human activities on the coastal environment of Chile.

Outcome of long benign esophageal strictures undergoing endoscopictherapy: a tertiary center experience.

COMPLEX BENIGN ESOPHAGEAL STRICTURES ARE DEFINED BY LENGTH (≥2 CM), SMALL DIAMETER, AND STRICTURE ANGULATION OR TORTUOSITY. THE LONG-TERM COURSE OF COMPLEX ESOPHAGEAL STRICTURES BASED ON LENGTH IS CURRENTLY UNCLEAR. WE SUSPECT THAT THE ESOPHAGEAL STRICTURE LENGTH MIGHT IMPACT THE EFFECTIVENESS OF ENDOSCOPIC DILATION THERAPY. WE PERFORMED A RETROSPECTIVE STUDY OF ALL BENIGN ESOPHAGEAL STRICTURES OF 2 CM OR LONGER TREATED AT A SINGLE CENTER BETWEEN JULY 1, 2010, AND MAY 31, 2014. PRIMARY OUTCOMES WERE CHANGED IN DYSPHAGIA SCORE AT THE END OF FOLLOW-UP COMPARED TO FIRST DILATION AT OUR FACILITY AND THE NEED FOR GASTROSTOMY PLACEMENT OR ESOPHAGECTOMY DURING FOLLOW-UP. DATA WERE STRATIFIED INTO FOUR SUBGROUPS ACCORDING TO STRICTURE LENGTH 20­29, 30­49, 50­99, AND 100 MM OR LONGER. EIGHTY-SEVEN PATIENTS (MEAN AGE 66 YEARS, 54% WOMEN) WERE FOLLOWED OVER A MEDIAN OF 40 MONTHS. PATIENTS UNDERWENT A MEDIAN OF 6 DILATIONS, AVERAGING 0.3 DILATIONS PER MONTH. MEDIAN DYSPHAGIA SCORE REMAINED UNCHANGED AT 2; 37 (43%) PATIENTS REPORTED RESOLUTION OR IMPROVED DYSPHAGIA AND 50 (57%) PATIENTS REPORTED NO IMPROVEMENT OR WORSENED DYSPHAGIA. GASTROSTOMY PLACEMENT OR ESOPHAGECTOMY WAS NEEDED FOR 23 (26%) AND 3 (3%) PATIENTS, RESPECTIVELY. MEDIAN DEGREE OF DYSPHAGIA AT THE END OF FOLLOW-UP DID NOT DIFFER BETWEEN THE FOUR STRICTURE LENGTH SUBGROUPS, YET NO PATIENT HAD IMPROVEMENT IN THE 100 MM OR LONGER SUBGROUP. MORE THAN HALF OF PATIENTS WITH LONG BENIGN ESOPHAGEAL STRICTURES HAD UNCHANGED DYSPHAGIA OR DEVELOPED WORSE DYSPHAGIA DURING FOLLOW-UP. LONG-TERM OUTCOMES DID NOT DIFFER BETWEEN DIFFERENT STRICTURE LENGTHS: .

Impact of immunosuppressive therapy on therapy-neutralizing antibodies in transplanted patients with Fabry disease.

BACKGROUND: Inhibitory antibodies towards enzyme replacement therapy (ERT) are associated with disease progression and poor outcome in affected male patients with lysosomal disorders such as Fabry disease (FD). However, little is known about the impact of immunosuppressive therapy on ERT inhibition in these patients with FD. METHODS: In this retrospective study, we investigated the effect of long-term immunosuppression on ERT inhibition in male patients with FD (n = 26) receiving immunosuppressive therapy due to kidney (n = 24) or heart (n = 2) transplantation. RESULTS: No ERT-naïve transplanted patient (n = 8) developed antibodies within follow-up (80 ±72 months) after ERT initiation. Seven (26.9%) patients were tested ERT inhibition positive prior to transplantation. No de novo ERT inhibition was observed after transplantation (n = 18). In patients treated with high dosages of immunosuppressive medication such as prednisolone, tacrolimus and mycophenolate-mofetil/mycophenolate acid, ERT inhibition decreased after transplantation (n = 12; P = 0.0160). Tapering of immunosuppression (especially prednisolone) seemed to re-increase ERT inhibition (n = 4, median [range]: 16.6 [6.9; 36.9] %; P = 0.0972) over time. One ERT inhibition-positive patient required interventions with steroid therapy and increased doses of tacrolimus, which also lowered ERT inhibition. CONCLUSION: We conclude that the immunosuppressive maintenance therapy after transplantations seems to be sufficient to prevent de novo ERT inhibition in ERT-naïve patients. Intensified high dosages of immunosuppressive drugs are associated with decreased antibody titres and decreased ERT inhibition in affected patients, but did not result in long-term protection. Future studies are needed to establish ERT inhibition-specific immunosuppressive protocols with long-term modulating properties to warrant an improved disease course in ERT inhibition-positive males.

Physical Exercise in Patients with Fabry Disease - a Pilot Study.

The aim of this study was to assess the extent of exercise intolerance in Fabry disease (FD) patients and to report individual effects of physical exercise. Exercise capacity and strength of 14 patients (mean age 46 years, 6 females) were determined using cycle ergometry and isokinetic measurements. Patients performed a strength/circuit exercise training protocol for 12 months. The mean relative maximum performance of the group was low at baseline and increased by 12.1% (baseline: 1.9 [0.9-3.4] W·kg-1vs. re-test: 2.1 [1.1-3.8] W·kg-1; p=0.035) during the study. Patients' mean baseline maximum performance blood lactate of 5.4 [1.3-9.9] mmol·L-1 increased to a mean of 7.2 (2.4-10.2) mmol·L-1 (p=0.038). Mean strength of the lower limbs (left/right extensors and flexors, total work of 5 sets) changed from 2269 (1017-2913) kg·m2·s - 2 to 2325 (1359-3107) kg·m2·s-2 (not significant). Patients reported increased well-being, daily activity and reduced fatigue during the study. Our results indicate that exercise intolerance in FD patients often results from physical inactivity. FD patients may perform exercise training to improve exercise capacity and muscle strength. Future studies will address the clinical benefits of exercise in FD.

[Pain therapy for Fabry's disease]. / Schmerztherapie bei Morbus Fabry.

Fabry's disease is an X-chromosome linked lysosomal storage disorder with α-galactosidase A deficiency and subsequent multiple organ involvement. An early and common symptom also in later stages of the disease is pain. This pain depends on various precipitating factors and can severely compromise the quality of life. So-called Fabry crises can lead to the necessity for intensive care treatment. The pain can be classified as predominantly neuropathic and is difficult to treat. In addition, medication has to be adjusted to concomitant cardiac and renal involvement in Fabry's disease. This review gives guidance for pain therapy in Fabry's disease based on the available evidence and on experience.

Imiquimod 5% cream as pretreatment of Mohs micrographic surgery for nodular basal cell carcinoma in the face: a prospective randomized controlled study.

BACKGROUND: Imiquimod 5% cream can reduce or clear superficial and small nodular basal cell carcinoma (BCC). It could be used as a pretreatment of Mohs micrographic surgery (MMS) to decrease defect size. OBJECTIVES: To study if a pretreatment with imiquimod 5% cream decreases defect size after MMS. In addition, to study the effect on the number of Mohs stages and reconstruction time. METHODS: Seventy patients aged >18 years with a primary nodular BCC in the face were included. The imiquimod group used imiquimod 5% cream for 4 weeks, before MMS. The control group was treated with MMS only. Tumour and defect sizes were measured. We noted the number of Mohs stages, reconstruction time and side-effects. RESULTS: The median percentage increase in area from tumour size at baseline to the post-MMS defect for the imiquimod group was significantly less compared with the control group, 50% vs. 147% (P < 0·001). A tendency towards fewer Mohs stages in the imiquimod group was observed and the reconstruction time was significantly shorter in this group (P = 0·01). CONCLUSIONS: Imiquimod 5% cream as pretreatment of MMS significantly reduced the tumour size in primary nodular BCC and reduced the surgical defect size. Further research is necessary to investigate cost-effectiveness.

Arterial properties in relation to genetic variation in alpha-adducin and the renin-angiotensin system in a White population.

Earlier studies have demonstrated the interaction between ADD1 and ACE in relation to arterial properties. We investigated whether arterial characteristics might also be related to interactions of ADD1 with other renin-angiotensin system genes. Using a family-based sampling frame, we randomly recruited 1064 Flemish subjects (mean age, 43.6 years; 50.4% women). By means of a wall-tracking ultrasound system, we measured the properties of the carotid, femoral and brachial arteries. In multivariate-adjusted analyses, we assessed the multiple gene effects of ADD1 (Gly460Trp), AGT (C-532T and G-6A) and AT1R (A1166C). In ADD1 Trp allele carriers, but not in ADD1 GlyGly homozygotes (P-value for interaction < or =0.014), femoral cross-sectional compliance was significantly higher (0.74 vs 0.65 mm(2) kPa(-1); P=0.020) in carriers of the AT1R C allele than in AT1R AA homozygotes, with a similar trend for femoral distensibility (11.3 vs 10.2 x 10(-3) kPa(-1); P=0.055). These associations were independent of potential confounding factors, including age. Family-based analyses confirmed these results. Brachial diameter (4.35 vs 4.18 mm) and plasma renin activity (PRA) (0.23 vs 0.14 ng ml(-1) h(-1)) were increased (P< or =0.005) in AGT CG haplotype homozygotes compared with non-carriers, whereas the opposite was true for brachial distensibility (12.4 vs 14.4 x 10(-3) kPa(-1); P=0.011). There was no interaction between AGT and any other gene in relation to the measured phenotypes. ADD1 and AT1R interactively determine the elastic properties of the femoral artery. There is a single-gene effect of the AGT promoter haplotypes on brachial properties and PRA.

[Risk assessment by means of polygraphy]. / Risicotaxatie met de polygraaf.

BACKGROUND: Polygraphy (the popular name is lie detection) is an activity that is hotly debated. This article puts forward arguments for and against the use of polygraphy. First of all a framework for lie detection is presented and thereafter the theoretical basis and practical aspects of the use of lie detection for risk assessment are described. Finally the future prospects for polygraphy in risk assessment are described.

[Addiction and recidivism in forensic psychiatry]. / Verslaving als risicofactor in de forensische psychiatrie.

BACKGROUND: The prevalence of addiction in forensic psychiatric patients (adolescents and adults) is unknown. Published figures are nearly always based on estimates or on old or select samples. AIM: To determine the importance of addiction as a risk factor for recidivism in forensic psychiatric patients in the Netherlands and to determine the prevalence of addiction in this group and the prevalence of drug intoxication in group-members at the time they committed the offence. METHOD: We analysed one database relating to forensic psychiatric adolescents and two sets of data relating to tbs-patients (tbs='detained at her Majesty's pleasure'). RESULTS: The prevalence of addiction among forensic psychiatric patients could only be given approximately, but it was certainly high (more than 60%). Substance abuse or addiction often played a major role (in more than 30% of cases) at the time the offence was committed for which the detention order was issued. CONCLUSION: Because substance abuse often played a role in the delinquent behaviour that led to the detention order, it may also be a risk factor for recidivism. More research is needed so that we can increase our knowledge about the most effective ways of treating substance abuse.

Effect of clinical signs, endocrinopathies, timing of surgery, hyperlipidemia, and hyperbilirubinemia on outcome in dogs with gallbladder mucocele.

Gallbladder mucocele (GBM) is a common extra-hepatic biliary syndrome in dogs with death rates ranging from 7 to 45%. Therefore, the aim of this study was to identify the association of survival with variables that could be utilized to improve clinical decisions. A total of 1194 dogs with a gross and histopathological diagnosis of GBM were included from 41 veterinary referral hospitals in this retrospective study. Dogs with GBM that demonstrated abnormal clinical signs had significantly greater odds of death than subclinical dogs in a univariable analysis (OR, 4.2; 95% CI, 2.14-8.23; P<0.001). The multivariable model indicated that categorical variables including owner recognition of jaundice (OR, 2.12; 95% CI, 1.19-3.77; P=0.011), concurrent hyperadrenocorticism (OR 1.94; 95% CI, 1.08-3.47; P=0.026), and Pomeranian breed (OR, 2.46; 95% CI 1.10-5.50; P=0.029) were associated with increased odds of death, and vomiting was associated with decreased odds of death (OR, 0.48; 95% CI, 0.30-0.72; P=0.001). Continuous variables in the multivariable model, total serum/plasma bilirubin concentration (OR, 1.03; 95% CI, 1.01-1.04; P<0.001) and age (OR, 1.17; 95% CI, 1.08-1.26; P<0.001), were associated with increased odds of death. The clinical utility of total serum/plasma bilirubin concentration as a biomarker to predict death was poor with a sensitivity of 0.61 (95% CI, 0.54-0.69) and a specificity of 0.63 (95% CI, 0.59-0.66). This study identified several prognostic variables in dogs with GBM including total serum/plasma bilirubin concentration, age, clinical signs, concurrent hyperadrenocorticism, and the Pomeranian breed. The presence of hypothyroidism or diabetes mellitus did not impact outcome in this study.

[Risk assessment and treatment evaluation by means of two forensic observation instruments]. / Risicotaxatie en behandelevaluatie met twee forensische observatielijsten.

BACKGROUND: Under the Dutch TBS system (compulsory detention by government order), risk assessment and treatment evaluation are closely linked procedures. AIM: To test the psychometric properties of two observation instruments developed specifically for evaluating the treatment of persons compulsory detained (tbs). METHOD: Two observation instruments for the use of social therapists and/or group leaders were tested on the basis of measurements obtained at the 'Meijers Instituut'(n=556) and at the 'De Kijvelanden'(n=100). The two instruments, one called the STM list (list for social therapists) and the other called the 'coping list', are questionnaires. The lists are designed to measure characteristics such as social skills, cooperation, daily living skills and coping skills in forensic psychiatric patients. These characteristics are believed to be important predictors of risk of future criminal behaviour. RESULTS: The internal consistency for the two questionnaires was found to be good. The results obtained at 'De Kijvelanden' showed that the STM questionnaire had adequate test-retest reliability. The STM total scores and subscale scores were found to be significantly associated with criminal recidivism. Anti-social behaviour on the ward, daily living skills and social skills, and to a lesser extent cooperation and negative coping styles, were found to be associated with future relapse into criminal behaviour. CONCLUSION: The questionnaires appear to be suitable for repeated assessing the effects of treatment on behaviour in forensic psychiatric settings and could possibly serve as useful supplements to other risk assessment methods that are currently available.

Cannabis in Chinese Medicine: Are Some Traditional Indications Referenced in Ancient Literature Related to Cannabinoids?

Cannabis sativa L. (Cannabaceae) has a long history of utilization as a fiber and seed crop in China, and its achenes ("seeds") as well as other plant parts have been recorded in Chinese medical texts for nearly 2000 years. While the primary applications of cannabis in Chinese medicine center around the use of the achenes, ancient indications for the female inflorescence, and other plant parts include conditions such as pain and mental illness that are the subject of current research into cannabinoids such as cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). However, little previous research has been conducted to analyze the Chinese medical literature in light of recent advances in the pharmacology and taxonomy of cannabis, and most of the relevant Chinese historical records have not yet been translated into Western languages to facilitate textual research. Furthermore, many key questions remain unresolved in the Chinese literature, including how various traditional drug names precisely correspond to different plant parts, as well as the implications of long-term selection for fiber-rich cultivars on the medical applications of cannabis in Chinese medicine. In this article, prominent historical applications of cannabis in Chinese medicine are chronologically reviewed, and indications found in ancient Chinese literature that may relate to cannabinoids such as CBD and Δ9-THC are investigated.

Polymorphisms of the human matrix gla protein (MGP) gene, vascular calcification, and myocardial infarction.

The matrix Gla protein (MGP) is an important inhibitor of vessel and cartilage calcification that is strongly expressed in human calcified, atherosclerotic plaques and could modulate plaque calcification and coronary heart disease risk. Using a genetic approach, we explored this possibility by identifying polymorphisms of the MGP gene and testing their possible association with myocardial infarction (MI) and plaque calcification. Eight polymorphisms were identified in the coding and 5'-flanking sequences of the MGP gene. All polymorphisms were investigated in 607 patients with MI and 667 control subjects recruited into the ECTIM Study (Etude Cas-Témoins de l'Infarctus du Myocarde) and in 717 healthy individuals with echographically assessed arterial calcification and atherosclerosis who were participating in the AXA Study. In the ECTIM Study, alleles and genotypes were distributed similarly in patients and controls in the whole study group; in only 1 subgroup of subjects defined as being at low risk for MI were the concordant A-7 and Ala 83 alleles more frequent in patients with MI than in controls (P<0.003). In the AXA Study among subjects with femoral atherosclerosis, the same alleles were more common in the presence than the absence of plaque calcification (P<0.025). The other MGP polymorphisms were not associated with any investigated clinical phenotype. Transient transfection experiments with allelic promoter-reporter gene constructs and DNA-protein interaction assays were carried out to assess possible in vitro functionality of the promoter variants detected at positions -814, -138, and -7 relative to the start of transcription. When compared with the -138 T allele, the minor -138 C: allele consistently conferred a reduced promoter activity of -20% (P<0.0001) in rat vascular smooth muscle cells and of -50% (P<0.004) in a human fibroblast cell line, whereas the other polymorphisms, including -7, displayed no evidence of in vitro functionality. We conclude that the A-7 or Ala 83 alleles of the MGP gene may confer an increased risk of plaque calcification and MI; however, the observed relationships are weak or limited to subgroups of patients and therefore need confirmation.

Context-dependency of the relation between left ventricular mass and AGT gene variants.

In the European Project on Genes in Hypertension (EPOGH), we investigated in three populations to what extent in a family-based study, left ventricular mass (LVM) was associated with the C-532T and G-6A polymorphisms in the angiotensinogen (AGT) gene. We randomly recruited 221 nuclear families (384 parents and 440 offspring) in Cracow (Poland), Novosibirsk (Russia), and Mirano (Italy). Echocardiographic LVM was indexed to body surface area, adjusted for covariables, and subjected to multivariate analyses, using generalized estimating equations and quantitative transmission disequilibrium tests in a population-based and family-based approach, respectively. We found significant differences between the two Slavic centres and Mirano in left ventricular mass index (LVMI) (94.9 vs 80.4 g/m2), sodium excretion (229 vs 186 mmol/day), and the prevalence of the AGT -6A (55.7 vs 40.6%) and -532T (16.8 vs 9.4%) alleles. In population-based as well as in family-based analyses, we observed positive associations of LVMI and mean wall thickness (MWT) with the -532T allele in Slavic, but not in Italian male offspring. Furthermore, in Slavic male offspring, LVMI and MWT were significantly higher in carriers of the -532T/-6A haplotype than in those with the -532C/-6G or -532C/-6A allele combinations. In women, LVMI was neither associated with single AGT gene variants nor with the haplotypes (0.19 < P <0.98). In Slavic offspring carrying the AGT -532C/-6G or -532C/-6A haplotypes, LVMI significantly increased with higher sodium excretion (+3.5 g/m2/100 mmol; P=0.003), whereas such association was not present in -532T/-6A haplotype carriers (P-value for interaction 0.04). We found a positive association between LVMI and the AGT -532T allele due to increased MWT. This relation was observed in Slavic male offspring. It was therefore dependent on gender, age and ecogenetic context, and in addition it appeared to be modulated by the trophic effects of salt intake on LVM.

Identification of two polymorphisms in the early growth response protein-1 gene: possible association with lipid variables.

Early growth response factor (EGR)-1 may play an important role in the development of atherosclerosis by inducing the expression of several relevant genes which contribute to the complex modulation of vascular structure and function, leading to vascular occlusive lesions. To investigate the possible role of molecular variants in the human EGR-1 gene for the predisposition to atherosclerosis or coronary heart disease we screened the 5'- and 3'- flanking regions and the entire coding sequence for polymorphisms by polymerase chain reaction/single-strand conformation polymorphism analysis and sequencing. Male patients (n=615) with myocardial infarction and 720 age-matched, male control subjects of the Etude Cas-Témoin de l'Infarctus du Myocarde were genotyped for two newly identified polymorphisms in the 5'- (C-151T) and 3'- (T+861C) flanking region of the EGR-1 gene using hybridization with allele-specific oligonucleotides. Allele and genotype frequencies did not significantly differ between patients with myocardial infarction and control subjects without coronary heart disease. In controls not taking hypolipidemic drugs there was a significant association of the -151T allele with lower plasma levels of total cholesterol (P=0.029), low-density lipoprotein cholesterol (P=0.025) and apolipoprotein B (P=0.038) and a higher ratio of high-density to low-density lipoprotein (P=0.049) than with the C-151 allele. We conclude that the C-151T polymorphism of the EGR-1 gene may contribute to modifications of the lipid metabolism. Our findings need to be replicated in independent studies, and in vitro promoter studies should evaluate the functional consequence of the -151T allele, which disrupts a consensus core sequence for the ubiquitous transcription factor activator protein 4.

Polymorphisms in the genes encoding platelet-derived growth factor A and alpha receptor.

Platelet-derived growth factors (PDGFs) may play an important role in the development of atherosclerosis acting as chemoattractants and mitogens for vascular smooth muscle cells and macrophages. Three dimeric forms of PDGF (AA, AB, BB) have different activities due to distinct binding properties mediated by two types of PDGF receptors (Ralpha, Rbeta). To investigate the possible contribution of molecular variants in the human PDGF-A and PDGF-Ralpha genes to coronary heart disease we screened these genes for polymorphisms by polymerase chain reaction/single-strand conformation polymorphism analysis. A total of 600 men with myocardial infarction and 717 age-matched male controls from four populations in Northern Ireland and France (the ECTIM Study) were gneotyped for newly identified polymorphisms in the genes encoding PDGF-A (C-26IN3T, H69H, C+12IN5T) and PDGF-Ralpha [-1630 I/D (+/-AACTT), A-1506G, C-1390G, G-956A, C-908A, G-793T, +69 I/D (+/-GA)] using allele-specific oligonucleotides. All PDGF-Ralpha polymorphisms, except C-908A, involving a nucleotide change in a common consensus site for GCF and SP-1 transcription factors, were in nearly complete association, generating two major haplotypes. The PDGF-A and PDGF-Ralpha polymorphisms provided a heterozygosity of 0.69 and 0.40, respectively. Genotype and allele frequencies of the PDGF-A and PDGF-Ralpha polymorphisms did not differ between patients with myocardial infarction and controls in either country. None of the polymorphisms investigated was associated with blood pressure, coronary artery stenosis, or any biochemical parameter available in the ECTIM Study.

Glucagon receptor gene mutation (Gly40Ser) in human essential hypertension: the PEGASE study.

A missense mutation (Gly40Ser) in exon 2 of the glucagon receptor gene (GCG-R) was shown to reduce ligand affinity and impair cAMP response. We conducted a case-control study with a sample of 741 French hypertensive patients with moderate to severe hypertension and 412 normotensive control subjects, who were genotyped for this biallelic variant by use of hybridization with allele-specific oligonucleotides. The Gly40Ser polymorphism was not significantly associated with hypertension in the whole study population, although the frequency of 40Ser carriers in hypertensive subjects was double that in normotensive subjects (3.1% in hypertensives versus 1.5%; P=0.087). However, the separate analysis of both genders revealed that 40Ser allele carriers were significantly more frequent (P=0. 035) among male patients (17/429; 4.0%) than among normotensive male controls (2/242; 0.8%), whereas no significant difference was observed in female subjects (6/312 in hypertensives and 4/170 in normotensives). Further studies are required to interpret the significance of this association.

Genotype-phenotype relationships for the renin-angiotensin-aldosterone system in a normal population.

The renin-angiotensin-aldosterone system plays an important role in blood pressure regulation by influencing salt-water homeostasis and vascular tone. The purpose of the present study was to search for associations of single nucleotide polymorphisms on 3 major candidate genes of this system with the plasma concentrations of the corresponding renin-angiotensin-aldosterone system components considered as quantitative phenotypes. Genotyping was performed in 114 normotensive subjects for different variants of the angiotensinogen (AGT) gene (C-532T, G-6A, M235T), the angiotensin I-converting enzyme (ACE) gene [4656(CT)(2/3)], the aldosterone synthase (CYP11B2), and the type 1 angiotensin II receptor (AT1R) gene (A1166C) by hybridization with allele-specific oligonucleotides (ASO) or enzymatic digestion of polymerase chain reaction products. Plasma levels of AGT, ACE, angiotensin II (Ang II), aldosterone, and immunoreactive active renin were measured according to standard techniques. Platelet binding sites for Ang II were analyzed by the binding of radioiodinated Ang II to purified platelets. B(max) and K(D) values of the Ang II binding sites on platelets of each individual were calculated to examine a possible relationship between these parameters and the AT1R genotype. A highly significant association of the ACE 4656(CT)(2/3) variant with plasma ACE levels was observed (P<0.0001). ANOVA showed a significant effect of the AGT C-532T polymorphism on AGT plasma levels (P=0.017), but no significant effect was detectable with the other AGT polymorphisms tested, such as the G-6A or the M235T. A significant effect association was also found between the C-344T polymorphism of the CYP11B2 gene and plasma aldosterone levels, with the T allele associated with higher levels (P=0.02). No genotype effect of the AT1R A1166C polymorphism was detected either on the B(max) or the K(D) value of the Ang II receptors on platelets.

Evaluation of the angiotensinogen locus in human essential hypertension: a European study.

Different family and case-control studies support genetic linkage and association at the human angiotensinogen (AGT) locus with essential hypertension. To extend these previous observations, a European collaborative study of nine centers was set up to create a large resource of affected sibling pairs. The AGT locus was studied using a highly polymorphic dinucleotide repeat in the 3'-flanking region of the gene in 350 European families, comprising 630 affected sibling pairs. Statistical analyses using two different methods did not show any evidence for linkage either in the whole panel or in family subsets selected for severity or early onset of disease. Although several arguments from association studies suggest a role of the AGT gene in essential hypertension, this large family study did not replicate the initial linkage reported in smaller studies. Our results highlight the difficulty of identifying susceptibility genes by linkage analysis in complex diseases.