The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

A complexity science perspective on the impact of adverse socioeconomic conditions on chronic stress

 

Chronic stress increases chronic disease risk and may underlie the association between adverse socioeconomic conditions and adverse health outcomes. The relationship between such conditions and chronic stress is complex due to feedback loops between stressor exposure and psychological processes, encompassing different temporal (acute stress response to repeated exposure over the life course) and spatial (biological/psychological/social) scales. We examined this relationship from a complexity science perspective. We developed a causal loop diagram to interpret available evidence. Literature evidence was used to confirm/contest the variables and causal links included in the conceptual framework and refine their conceptualisation. Our findings were evaluated by 8 independent researchers. Adverse socioeconomic conditions imply an accumulation of stressors and increase the likelihood of exposure to uncontrollable childhood and life course stressors. Repetition of such stressors may activate mechanisms that can affect coping resources and coping strategies and stimulate appraisal of subsequent stressors as uncontrollable. We identified 5 feedback loops describing these mechanisms: progressive deterioration of access to coping resources because of repeated insolvability of stressors; perception of stressors as uncontrollable due to learned helplessness; tax on cognitive bandwidth caused by stress; stimulation of problem avoidance to provide relief from the stress response and free up cognitive bandwidth; susceptibility to appraising stimuli as stressors against a background of stress. The complexity science perspective revealed that adverse socioeconomic conditions imply recurrent stressor exposure which impacts chronic stress via amplifying feedback loops that together could be conceptualised as one vicious cycle. Therefore, in order for individual-level psychological interventions to be effective, the context of adverse socioeconomic conditions also needs to be addressed.

Key messages

We examined the mechanisms underlying the relationship between adverse socioeconomic conditions and chronic stress from a complexity science perspective, focusing on amplifying feedback loops. The complexity science perspective illustrates that interventions are unlikely to be successful if they focus only on individual-level psychological factors.

Developing a literature-based systems map of determinants of dietary intake in low-income groups

Background

Inequalities in obesity and related non-communicable diseases pertain in part to less healthy dietary intake in disadvantaged groups. Examining determinants of intake as a complex adaptive system - i.e. interconnected determinants exerting non-linear influence on outcomes - honours the complexity of dietary choices, behaviours and intake, and could inform policies. This study used literature to map the complex system underlying dietary intake in low-income groups, to identify system structure and goals perpetuating poorer dietary outcomes.

Methods

A systematic umbrella literature review examined determinants of dietary outcomes in children, adolescents and adults. Inclusion criteria were: • Low-income sample; analysis by income (Non-)systematic review of quantitative/qualitative, observational/intervention studiesHigher/upper-middle-income countriesExposures: individual, sociocultural, physical, political determinants/correlates; effect modifiers

Excluded outcomes were: breastfeeding, alcohol and neophobia.

Using causal loop diagramming, extracted data on determinants, associations and interpretation were embedded in a systems map of mechanisms driving dietary intake. System structure (e.g. sub-systems) and goals (e.g. feedback loops) were analysed.

Results

A systems map of hypothesised mechanisms driving dietary intake in low-income groups was developed from 43 reviews and expert consensus. The system comprised sub-systems: 1) accessibility, 2) household resources, 3) financial constraints, 4) health/biology, 5) knowledge, attitudes and beliefs, 6) sociocultural influences. Identified sub-system goals could undermine healthy intake opportunities, e.g. energy-dense food choices for cost-efficiency, heightened exposure to energy-dense foods determining preferences.

Conclusions

The literature-based systems map articulates the systemic basis of poorer dietary outcomes in low-income groups. Understanding system structure and goals will inform equitable policy.

Key messages

Dietary intake in low-income groups is driven by a complex system of mechanisms which may perpetuate poorer dietary outcomes. Existing literature was synthesised as a systems map; identification of structures and goals of the system can inform health equity policies.

[Nutrition and mental disorders during the life span: an overview of scientific evidence]

Nutritional interventions are scarcely used in the prevention and treatment of mental disorders.<br/> AIM: To summarize scientific evidence on the relation between nutrition and mental health, across the life span.<br/> METHOD: An overview of the literature based on recent knowledge syntheses, meta-analyses and original studies.<br/> RESULTS: Healthy dietary patterns are associated with a lower risk for depressive symptoms among adults and potentially also among children and adolescents. Dietary interventions can be effective in reducing depressive symptoms among high-risk groups and can have a beneficial effect in the treatment of depression. Meta-analyses of randomised studies have shown that omega-3 fatty acid supplements can be of added value in the treatment of adhd in children and of depression in adults.<br/> CONCLUSION: Promotion of healthy dietary patterns in line with National guidelines for healthy diets is important in the entire spectrum from good mental health to a chronic disorder. More attention for improving healthy dietary patterns among patients with mental disorders can lead to important health gains.

Validation of the SQUASH Physical Activity Questionnaire in a Multi-Ethnic Population: The HELIUS Study

PURPOSE

To investigate the reliability and validity of the SQUASH physical activity (PA) questionnaire in a multi-ethnic population living in the Netherlands.

METHODS

We included participants from the HELIUS study, a population-based cohort study. In this study we included Dutch (n = 114), Turkish (n = 88), Moroccan (n = 74), South-Asian Surinamese (n = 98) and African Surinamese (n = 91) adults, aged 18-70 years. The SQUASH was self-administered twice to assess test-re-test reliability (mean interval 6-7 weeks) and participants wore an accelerometer and heart rate monitor (Actiheart) to enable assessment of construct validity.

RESULTS

We observed low test-re-test reliability; Intra class correlation coefficients ranged from low (0.05 for moderate/high intensity PA in African Surinamese women) to acceptable (0.78 for light intensity PA in Moroccan women). The discrepancy between self-reported and measured PA differed on the basis of the intensity of activity: self-reported light intensity PA was lower than measured but self-reported moderate/high intensity PA was higher than measured, with wide limits of agreement. The discrepancy between questionnaire and Actiheart measures of moderate intensity PA did not differ between ethnic minority and Dutch participants with correction for relevant confounders. Additionally, the SQUASH overestimated the number of participants meeting the Dutch PA norm; Cohen's kappas for the agreement were poor, the highest being 0.30 in Dutch women.

CONCLUSION

We found considerable variation in the test-re-test reliability and validity of self-reported PA with no consistency based on ethnic origin. Our findings imply that the SQUASH does not provide a valid basis for comparison of PA between ethnic groups.

Air-freshener burns: a new paradigm in burns etiology?

OBJECTIVES

We report a rare case of burns following the use of automated air-fresheners.

METHODS

We present a case report with a brief overview of the literature relating to burns associated with air-fresheners. The mechanism and treatment of these types of injuries are also described.

RESULTS

A 44 year-old female was admitted under the care of the burns team following burns secondary to an exploding air-freshener canister. The patient sustained burns to the face, thorax and arms resulting in a seven-day hospital admission. The burns were treated conservatively.

CONCLUSIONS

To our knowledge this is one of the few documented cases of burns as a result of air-fresheners. As they become more ubiquitous, we anticipate the incidence of such cases to increase. As such, they pose a potential public health concern on a massive scale.

A cross-national comparative study of blood pressure and hypertension between English and Dutch South-Asian- and African-origin populations: the role of national context

BACKGROUND

We compare patterns of blood pressure (BP) and prevalence of hypertension between white-Dutch and their South-Asian and African minority groups with their corresponding white-English and their South-Asian and African ethnic minority groups; and the contribution of physical activity, body sizes, and socioeconomic position (SEP); and the quality of BP treatment that may underlie differences in mean BP.

METHODS

Secondary analyses of population-based studies of 13,999 participants from the United Kingdom and the Netherlands.

RESULTS

Compared with Dutch South-Asians, all English South-Asian men and women had lower BP and prevalence of hypertension except for systolic BP in English-Indian men. Among Africans, the systolic BP did not differ, but the diastolic BP levels were lower in English-Caribbean and English- (sub-Sahara) African men and women than in their Dutch-African counterparts. English-Caribbeans had a lower prevalence of hypertension than Dutch-Africans. Compared with white-Dutch, white-English men and women had higher systolic BP levels, but lower diastolic BP levels. There were no differences in the prevalence of hypertension between the white groups. Most differences remained unchanged after adjustment for SEP, lifestyle, and body sizes in all ethnic groups. BP control rates were substantially lower among Dutch-African and Dutch South-Asian hypertensives than among their English counterparts (except Indians).

CONCLUSIONS

We found marked variations in BP and hypertension prevalence between comparable ethnic groups in England and the Netherlands. Poor BP control among Dutch South-Asians and Africans contributed to their disadvantage of the relatively high BP levels.

Risk groups for overweight and obesity among Turkish and Moroccan migrants in The Netherlands

OBJECTIVES

The association between sociodemographic factors and acculturation with overweight/obesity in Turks and Moroccans was studied to identify target groups for prevention.

STUDY DESIGN

A cross-sectional study was undertaken among a sample of 1384 Turks and Moroccans aged 35-74 years in Amsterdam, The Netherlands.

METHODS

Data were collected by structured face-to-face interviews. Body mass index (BMI) was calculated from self-reported height and weight data. Sociodemographic variables collected were sex, age, educational level, marital status, parity and income level. Acculturation was measured by cultural orientation and length of residence in The Netherlands. Data of 1095 Turks and Moroccans were analysed using logistic regression, with overweight/obesity (BMI 25.0) as the dependent variable.

RESULTS

The prevalence of overweight/obesity was high (57-89%). Age, marital status, parity, income level, cultural orientation and length of residence were not associated or only weakly associated with overweight/obesity. Educational level and overweight/obesity were strongly associated in Turkish women (odds ratio 4.56; 95% confidence intervals 1.54-13.51).

CONCLUSIONS

The high prevalence of overweight/obesity in Turkish and Moroccan migrants varies little across sociodemographic groups and is not associated with acculturation. Poorly educated Turkish women are at particularly high risk.

Acculturation and education level in relation to quality of the diet: a study of Surinamese South Asian and Afro-Caribbean residents of the Netherlands

BACKGROUND

To consider the changes in overall diet quality following migration we examined the associations of acculturation variables and education level with diet in Surinamese South Asian and Surinamese Afro-Caribbean origin on the one hand, and ethnic Dutch residents of the Netherlands on the other. Surinam is a former Dutch colony in South America.

METHODS

We randomly selected men and women aged 35-60 years: ethnic Dutch, n = 552; South Asian, n = 306; Afro-Caribbean, n = 660. Intakes of fruit, vegetables, red meat, fish, vegetable oils, breakfast and salt were measured using a short questionnaire that formed the basis for a 'diet quality indicator' score. Highest education was measured and acculturation of the Surinamese groups was assessed by age at migration, number of resident years and a scale measure of social contacts with ethnic Dutch.

RESULTS

Compared with ethnic Dutch, both Surinamese groups scored higher on overall diet quality (P < or = 0.001) but some aspects of diet (breakfast and salt use) were less prudent. Education was positively associated with diet quality in ethnic Dutch (P < or = 0.01), but not consistently so in Surinamese. Associations with social contact with ethnic Dutch varied for different quality aspects of the diet. Residence duration (mean = 22 years) and age at migration (mean = 21 years) were not associated with diet.

CONCLUSIONS

A greater degree of acculturation does not necessarily lead to a less healthful diet in migrants. In addition, the association of education level with diet may differ for migrant groups. The diet of migrants differ from host populations, suggesting that migrant groups should be considered in the development of nutrition health promotion activities.

Early outcomes in the elderly: a meta-analysis of 4921 patients undergoing coronary artery bypass grafting--comparison between off-pump and on-pump techniques

OBJECTIVE

To assess early outcomes in the elderly population undergoing coronary revascularisation with and without cardiopulmonary bypass (CPB).

METHODS

Meta-analysis of all retrospective, non-randomised studies comparing off-pump coronary artery bypass (OPCAB) versus CPB techniques in the elderly (> 70 years) between 1999 and 2005. Age-related early outcomes of interest were death, stroke, atrial fibrillation (AF), renal failure and length of stay in hospital. The random effects model was used. Sensitivity and heterogeneity were analysed.

RESULTS

Analysis of 14 non-randomised studies comprising 4921 patients (OPCAB, 1533 (31.1%) and CPB, 3388 (68.9%)) showed a significantly lower incidence of death in the OPCAB group (odds ratio (OR) 0.48, 95% CI 0.28 to 0.84). This effect was greater in OPCAB octogenarians (OR 0.26, 95% CI 0.12 to 0.57). The pattern of incidence of stroke among the OPCAB octogenarians (OR 0.19, 95% CI 0.07 to 0.56) was similar. The incidence of AF was lower in the OPCAB group (OR 0.77, 95% CI 0.61 to 0.97). The incidence of renal failure did not differ. Length of hospital stay was shorter in the OPCAB group, although with significant heterogeneity.

CONCLUSIONS

OPCAB may be associated with lower incidence of death, stroke and AF in the elderly, which may result in shorter length of hospital stay. A large randomised trial would confirm whether the elderly would benefit more from OPCAB surgery.

Comparison of laparoscopic and open ileocecal resection for Crohn's disease: a metaanalysis

BACKGROUND

The role of laparoscopic surgery for patients with ileocecal Crohn's disease is a contentious issue. This metaanalysis aimed to compare open resection with laparoscopically assisted resection for ileocecal Crohn's disease.

METHODS

A literature search of the Medline, Ovid, Embase, and Cochrane databases was performed to identify comparative studies reporting outcomes for both laparoscopic and open ileocecal resection. Metaanalytical techniques were applied to identify differences in outcomes between the two groups. Sensitivity analysis was undertaken to evaluate the heterogeneity of the study.

RESULTS

Of 20 studies identified by literature review, 15 satisfied the criteria for inclusion in the study. These included outcomes for 783 patients, 338 (43.2%) of whom had undergone laparoscopic resection, with an overall conversion rate to open surgery of 6.8%. The operative time was significantly longer in the laparoscopic group, by 29.6 min (p = 0.002), although the blood loss and complications in the two groups were similar. In terms of postoperative recovery, the laparoscopic patients had a significantly shorter time for recovery of their enteric function and a shorter hospital stay, by 2.7 days (p < 0.001).

CONCLUSIONS

For selected patients with noncomplicated ileocecal Crohn's disease, laparoscopic resection offered substantial advantages in terms of more rapid resolution of postoperative ileus and shortened hospital stay. There was no increase in complications, as compared with open surgery. The contraindications to laparoscopic approaches for Crohn's disease remain undefined.

Spontaneous rupture of a true uterine artery aneurysm: a cause of retroperitoneal haematoma

We report the first case of spontaneous rupture of a true uterine artery aneurysm in a 69-year-old woman presenting with severe abdominal pain, a left iliac fossa mass, anaemia and a retroperitoneal haematoma on CT scanning. In this patient, the aneurysm was successfully embolised using microcoils. The different imaging modalities used for diagnosis and the treatment options are discussed.

Successful use of Botulinum toxin-A for the treatment of neck and anterior chest wall flushing

Neck and anterior chest wall flushing can be a social handicap to the sufferer and current treatment options are often unsatisfactory. We report the case of a 48-year-old woman with severe flushing of the anterior neck and anterior chest wall which resolved after three treatments of intracutaneous botulinum toxin A injections. We believe that this treatment method for skin flushing is simple, effective and free of significant side effects at these sites. Further studies are needed to evaluate the duration of the therapeutic effect.

Regulatory region variability in the human presenilin-2 (PSEN2) gene: potential contribution to the gene activity and risk for AD

We have analyzed the 5'-upstream promoter region of the presenilin 2 gene (PSEN2) for regulatory elements and examined Alzheimer disease (AD) patients and non-demented individuals for polymorphisms in the 5' upstream promoter region of the PSEN2 gene. Direct sequencing analysis detected a common single adenine (A) nucleotide deletion polymorphism in the upstream promoter region of the PSEN2 gene. Examination of cohorts of AD patients and age-matched control individuals revealed no statistically significant differences in the frequency of this polymorphism when compared with the total sample of AD patients and control individuals. However, subgroup and regression analysis suggested that the relatively rare -A/-A genotype increases risk of AD among subjects lacking apolipoprotein E (APOE) epsilon4 and among persons ages 65 years and younger. DNA sequence and DNA-protein binding analysis demonstrated that this mutation negates binding with putative repressor transcription factor (TF), interferon regulatory factor 2 (IRF2), in nuclear extracts prepared from the aged human brain neocortex. However this mutation creates a potential regulatory element, C/EBPbeta, that is responsive to pro-inflammatory (PI) induction. The expression activity assay with luciferase reporter gene into normal human neural progenitor cells in primary culture shows that the mutant PSEN2 regulatory region exhibits a 1.8-fold higher level of basal expression and is sensitive to IL-1beta and Abeta42, but that it is synergistically induced 3.2-fold over the wild-type PSEN2 by [IL-1beta+Abeta42]. These results suggest that under Pl and oxygen stress conditions relatively minor variations in PSEN2 promoter DNA sequence structure can enhance PSEN2 gene expression and that consequently these may play a role in the induction and/or proliferation of a Pl response in AD brain.

The influence of the hypertensive patient's education in compliance with their medication

The purpose of this study was to examine the relationships between patient's education in compliance with their medical regimen and the external variables: (1) "years of schooling," (2) duration of treatment, and (3) compliance with the medical regimen. The hypothesis tested in this study was as follows: "Hypertensive individuals who are educated about the importance of their medication and about the consequences of not taking the prescribed dosage will show better compliance with their prescribed drug regimen than those who are not thus educated." The sample of the study consisted of 40 hypertensive patients. A "posttest-only" control group design was used in this study. The hypothesis of the study was tested by using the Mann-Whitney U test. For the relationship between the external variables (years of schooling, duration of treatment, and compliance with the medical regimen), the Spearman test was used. The findings of the study revealed a statistically significant difference between compliance levels in the experimental group and in the control group (U = 130, p < 0.05), a positive correlation between "years of schooling" and compliance (rs = 0.33, p = 0.04), and a negative correlation between duration of treatment and compliance (rs = -0.45, p = 0.005). The findings support the hypothesis of the study.

Mutations in the open reading frame of the beta-site APP cleaving enzyme (BACE) locus are not a common cause of Alzheimer's disease

Amyloid beta-peptide (Abeta) plays a central role in the pathogenesis of Alzheimer's disease (AD). The gene encoding the beta-site APP cleaving enzyme (BACE), one of two enzymes that sequentially cleave the beta-amyloid precursor protein to generate Abeta, has recently been cloned. We tested the hypothesis that BACE might be genetically associated with AD by linkage analysis (56 pedigrees), by direct nucleotide sequencing of the entire open reading frame (20 subjects with familial AD, and 10 subjects with sporadic AD) and by allelic association analysis (155 AD cases and 173 non-demented controls). Our results revealed no evidence for either genetic linkage or allelic association between BACE and AD, and no coding sequence mutations were detected in the open reading frame of the BACE gene. These data suggest that while BACE protein plays an important role in the pathogenesis of AD, and may be a robust therapeutic target, it is unlikely to be a major AD susceptibility locus.

Genetic predisposition to stroke in relatives of hypertensives

BACKGROUND AND PURPOSE

The genetic basis of stroke is poorly understood. We evaluated patterns of familial aggregation of hypertension and stroke to test the hypothesis that inherited susceptibility to these disorders may be determined by a common set of factors.

METHODS

Genealogical and medical history information was obtained for a cohort of 354 hypertensive probands ascertained in a clinic-based setting, their 1427 first-degree relatives, and 239 of their spouses. Risks of stroke and hypertension in biological and nonbiological relatives were compared with the logistic model of the generalized estimating equations adjusted for age and sex.

RESULTS

The risk of hypertension was higher for the parents and siblings of the probands than for spouses (odds ratio [OR]=2.4; 95% CI, 1.8 to 3.4; OR=2.2; 95% CI, 1.6 to 3.0, respectively). When the spouses were used as a reference group, the risk of stroke for parents of the hypertensive probands was 7.3 times higher (OR=7.3; 95% CI, 3.6 to 14.8), while a nonsignificant but slightly increased risk for siblings (OR=1.6; 95% CI, 0.8 to 3.3) was observed. Controlling for hypertension, obesity, smoking, coronary heart disease, diabetes, and cholesterol resulted in decreased estimates of the risk of stroke for parents and siblings (OR(parents)=5.4; 95% CI, 2.6 to 11.2; OR(siblings)=1.2; 95% CI, 0.6 to 2.5). The risk of stroke was significantly higher for hypertensive parents and siblings than for nonhypertensive parents (OR=5.2; 95% CI, 2.8 to 9. 7) and siblings (OR=5.8; 95% CI, 2.1 to 15.9). A history of hypertension was not associated with an increased risk for stroke in spouses (OR=0.7; 95% CI, 0.2 to 3.1). The risk of stroke in hypertensive relatives of probands with stroke was higher than that of the normotensive relatives (OR=13.4). A less elevated risk ratio was observed in the relatives of probands who did not have a stroke (OR=4.0).

CONCLUSIONS

Our data showing a higher occurrence of hypertension and stroke in parents of hypertensive probands compared with spouses suggest that some of the genetic factors predisposing to these conditions may be the same. The slightly increased risk to siblings compared with spouses was not significant, suggesting that elucidation of these factors through family studies of stroke may be difficult because of secular trends toward improved treatment for hypertension. Although a history of hypertension increases the risk of stroke among parents and siblings, multivariate analyses revealed a familial component to stroke independent of hypertension.

Stratification techniques to explore genotype environment interactions

Linkage analysis was performed on the GAW11 Problem 2 data set using stratification to explore the effects of the environmental risk factors and the differences between mild and severe phenotypes. Analysis of the four study populations stratified by the two risk factors identified regions on chromosomes 3 and 5 with significant evidence for linkage. Other loci were sought by removing families consistent with linkage to the chromosome 3 locus. Our studies identified a locus on chromosome 3 (markers 43-46) associated with the mild phenotype in the presence of risk factor 1 and with the severe phenotype independent of risk factor 1. This suggests that distinct allelic variants at the chromosome 3 locus may cause different forms of disease. The locus identified on chromosome 5 (markers 36-39) was linked to the severe phenotype, but exposure to factor 1 or 2 may have a protective effect. The regions on chromosomes 3 and 5 appeared to have independent roles in disease etiology. Evidence for two loci on chromosome 1 linked to the mild form was found. The methods successfully identified linkages and interaction consistent with the generating model.

Power of concordant versus discordant sib pairs at different penetrance levels

Knowing the answers, we used the GAW11 data set to compare the power and efficiency of discordant versus concordant affected sib pairs for qualitative traits at different levels of penetrance. Samples of 200 concordant sib pairs outperformed discordant sib pairs for low penetrance (40%) and 70% penetrance models while at 90% penetrance they performed equally well. Increasing the sample size of discordant sib pairs to twice that of concordant pairs was not enough to reach the power of concordant sib pairs at the 40% and 70% penetrance models. For low penetrance using a combination of concordant and discordant sib pairs resulted in higher power than using discordant sib pairs alone. At 90% penetrance, the power of concordant and discordant sib pairs was similar in the region close to the gene while concordant sib pairs performed better at locations further from the gene.

Identification of a polymorphic glutamic acid stretch in the alpha2B-adrenergic receptor and lack of linkage with essential hypertension

Essential hypertension, a clinically significant elevation in blood pressure with no recognizable cause, is believed to be attributable to the collective effect of genetic predisposing factors in combination with specific environmental factors, such as diet and stress. Of the genetic causes, genes coding for proteins involved in blood pressure regulation, such as the alpha- and beta-adrenergic receptors, are obvious candidates. The alpha2-adrenergic receptor plays a key role in the sympathetic nervous system by mediating the effects of epinephrine and norepinephrine. To evaluate the potential role between the alpha2B receptor and essential hypertension, we scanned the alpha2B-receptor gene for genetic variation in 108 affected sibling pairs. The screening revealed two major forms of the receptor. They differ by the presence of either 9 or 12 glutamic acid residues in the acidic domain of the third cytoplasmic loop of the protein. Investigation of the pattern of this variation in hypertensive sibling pairs suggests that the alpha2B receptor locus does not contribute substantially to genetic susceptibility for essential hypertension.

Evidence for linkage between essential hypertension and a putative locus on human chromosome 17

Several clinical and animal studies indicate that essential hypertension is inherited as a multifactorial trait with a significant genetic and environmental component. In the stroke-prone spontaneously hypertensive rat model, investigators have found evidence for linkage to blood pressure regulatory genes (quantitative trait loci) on rat chromosomes 2, 10, and X. In 1 human study of French and UK sib pairs, evidence for linkage has been reported to human chromosome 17q, the syntenic region of the rat chromosome 10 quantitative trait loci (QTL). Our study confirms this linkage (P=0.0005) and refines the location of the blood pressure QTL.

Autosomal dominant orthostatic hypotensive disorder maps to chromosome 18q

Familial orthostatic hypotensive disorder is characterized by light-headedness on standing, which may worsen to syncope, palpitations, and blue-purple ankle discoloration, and is accompanied by a marked decrease in systolic blood pressure, an increase in diastolic pressure, and tachycardia, all of which resolve when supine. We ascertained three families in which this disorder is inherited as an autosomal dominant trait with reduced penetrance. A genomewide scan was conducted in the two largest families, and three regions with multipoint LOD scores >1.5 were identified. Follow-up of these regions with additional markers in all three families yielded significant evidence of linkage at chromosome 18q. A maximum multipoint LOD score of 3.21 in the three families was observed at D18S1367, although the smallest family had negative LOD scores in the entire region. There was significant evidence of linkage in the presence of heterogeneity at 18q, with a maximum LOD score of 3.92 at D18S1367 in the two linked families. Identification of the gene responsible for orthostatic hypotensive disorder in these families may advance understanding of the general regulatory pathways involved in the continuum, from hypotension to hypertension, of blood pressure.