Patterns of single-nucleotide polymorphisms in candidate genes for blood-pressure homeostasis

Sequence variation in human genes is largely confined to single-nucleotide polymorphisms (SNPs) and is valuable in tests of association with common diseases and pharmacogenetic traits. We performed a systematic and comprehensive survey of molecular variation to assess the nature, pattern and frequency of SNPs in 75 candidate human genes for blood-pressure homeostasis and hypertension. We assayed 28 Mb (190 kb in 148 alleles) of genomic sequence, comprising the 5' and 3' untranslated regions (UTRs), introns and coding sequence of these genes, for sequence differences in individuals of African and Northern European descent using high-density variant detection arrays (VDAs). We identified 874 candidate human SNPs, of which 22% were confirmed by DNA sequencing to reveal a discordancy rate of 21% for VDA detection. The SNPs detected have an average minor allele frequency of 11%, and 387 are within the coding sequence (cSNPs). Of all cSNPs, 54% lead to a predicted change in the protein sequence, implying a high level of human protein diversity. These protein-altering SNPs are 38% of the total number of such SNPs expected, are more likely to be population-specific and are rarer in the human population, directly demonstrating the effects of natural selection on human genes. Overall, the degree of nucleotide polymorphism across these human genes, and orthologous great ape sequences, is highly variable and is correlated with the effects of functional conservation on gene sequences.

Bovine beta-lactoglobulin at 1.8 A resolution--still an enigmatic lipocalin

BACKGROUND

beta-Lactoglobulin (beta-Lg) is the major whey protein in the milk of ruminants and many other mammals. Its function is not known, but it undergoes at least two pH-dependent conformational changes which may be important. Bovine beta-Lg crystallizes in several different lattices, and medium-resolution structures of orthorhombic lattice Y and trigonal lattice Z have been published. Triclinic lattice X and lattice Z crystals grow at pH values either side of the pH at which one of the pH-induced conformational changes occurs. A full understanding of the structure is needed to help explain both the conformational changes and the different denaturation behaviour of the genetic variants.

RESULTS

We have redetermined the structure of beta-Lg lattice Z at 3.0 A resolution by multiple isomorphous replacement and have partially refined it (R factor = 24.8%). Using the dimer from this lattice Z structure as a search model, the triclinic crystal form grown at pH 6.5 (lattice X) has been solved by molecular replacement. Refinement of lattice X at 1.8 A resolution gave an R factor of 18.1%. The structure we have determined differs from previously published structures in several ways.

CONCLUSIONS

Incorrect threading of the sequence in the published structures of beta-Lg affects four of the nine beta strands. The basic lipocalin fold of the polypeptide chain is unchanged, however. The relative orientation of the monomers in the beta-Lg dimer differs in the two lattices. On raising the pH, there is a rotation of approximately 5 degrees, which breaks a number of intersubunit hydrogen bonds. It is not yet clear, however, why the stability of the structure should depend so heavily upon the external loop around residue 64 or the beta strand with the free thiol, each of which shows genetic variation.

Agmatine: an endogenous clonidine-displacing substance in the brain

Clonidine, an antihypertensive drug, binds to alpha 2-adrenergic and imidazoline receptors. The endogenous ligand for imidazoline receptors may be a clonidine-displacing substance, a small molecule isolated from bovine brain. This clonidine-displacing substance was purified and determined by mass spectroscopy to be agmatine (decarboxylated arginine), heretofore not detected in brain. Agmatine binds to alpha 2-adrenergic and imidazoline receptors and stimulates release of catecholamines from adrenal chromaffin cells. Its biosynthetic enzyme, arginine decarboxylase, is present in brain. Agmatine, locally synthesized, is an endogenous agonist at imidazoline receptors, a noncatecholamine ligand at alpha 2-adrenergic receptors and may act as a neurotransmitter.

Estimating African American admixture proportions by use of population-specific alleles

We analyzed the European genetic contribution to 10 populations of African descent in the United States (Maywood, Illinois; Detroit; New York; Philadelphia; Pittsburgh; Baltimore; Charleston, South Carolina; New Orleans; and Houston) and in Jamaica, using nine autosomal DNA markers. These markers either are population-specific or show frequency differences >45% between the parental populations and are thus especially informative for admixture. European genetic ancestry ranged from 6.8% (Jamaica) to 22.5% (New Orleans). The unique utility of these markers is reflected in the low variance associated with these admixture estimates (SEM 1.3%-2.7%). We also estimated the male and female European contribution to African Americans, on the basis of informative mtDNA (haplogroups H and L) and Y Alu polymorphic markers. Results indicate a sex-biased gene flow from Europeans, the male contribution being substantially greater than the female contribution. mtDNA haplogroups analysis shows no evidence of a significant maternal Amerindian contribution to any of the 10 populations. We detected significant nonrandom association between two markers located 22 cM apart (FY-null and AT3), most likely due to admixture linkage disequilibrium created in the interbreeding of the two parental populations. The strength of this association and the substantial genetic distance between FY and AT3 emphasize the importance of admixed populations as a useful resource for mapping traits with different prevalence in two parental populations.

Trends and disparities in coronary heart disease, stroke, and other cardiovascular diseases in the United States: findings of the national conference on cardiovascular disease prevention

A workshop was held September 27 through 29, 1999, to address issues relating to national trends in mortality and morbidity from cardiovascular diseases; the apparent slowing of declines in mortality from cardiovascular diseases; levels and trends in risk factors for cardiovascular diseases; disparities in cardiovascular diseases by race/ethnicity, socioeconomic status, and geography; trends in cardiovascular disease preventive and treatment services; and strategies for efforts to reduce cardiovascular diseases overall and to reduce disparities among subpopulations. The conference concluded that coronary heart disease mortality is still declining in the United States as a whole, although perhaps at a slower rate than in the 1980s; that stroke mortality rates have declined little, if at all, since 1990; and that there are striking differences in cardiovascular death rates by race/ethnicity, socioeconomic status, and geography. Trends in risk factors are consistent with a slowing of the decline in mortality; there has been little recent progress in risk factors such as smoking, physical inactivity, and hypertension control. There are increasing levels of obesity and type 2 diabetes, with major differences among subpopulations. There is considerable activity in population-wide prevention, primary prevention for higher risk people, and secondary prevention, but wide disparities exist among groups on the basis of socioeconomic status and geography, pointing to major gaps in efforts to use available, proven approaches to control cardiovascular diseases. Recommendations for strategies to attain the year 2010 health objectives were made.

The prevalence of hypertension in seven populations of west African origin

OBJECTIVES

This study was undertaken to describe the distribution of blood pressures, hypertension prevalence, and associated risk factors among seven populations of West African origin.

METHODS

The rates of hypertension in West Africa (Nigeria and Cameroon), the Caribbean (Jamaica, St. Lucia, Barbados), and the United States (metropolitan Chicago, Illinois) were compared on the basis of a highly standardized collaborative protocol. After researchers were given central training in survey methods, population-based samples of 800 to 2500 adults over the age of 25 were examined in seven sites, yielding a total sample of 10014.

RESULTS

A consistent gradient of hypertension prevalence was observed, rising from 16% in West Africa to 26% in the Caribbean and 33% in the United States. Mean blood pressures were similar among persons aged 25 to 34, while the increase in hypertension prevalence with age was twice as steep in the United States as in Africa. Environmental factors, most notably obesity and the intake of sodium and potassium, varied consistently with disease prevalence across regions.

CONCLUSION

The findings demonstrate the determining role of social conditions in the evolution of hypertension risk in these populations.

Constituents of red yeast rice, a traditional Chinese food and medicine

Detailed analyses were undertaken of the natural constituents of red yeast rice, a traditional Chinese medicine and food known for centuries to improve blood circulation. Preparation of red yeast rice following ancient methods by fermenting the fungal strain Monascus purpureus Went on moist and sterile rice indicated the presence of a group of metabolites belonging to the monacolin family of polyketides, together with fatty acids, and trace elements. The presence of these compounds may explain in part the cholesterol-lowering ability associated with this traditional Chinese food.

International consensus outcome measures for patients with idiopathic inflammatory myopathies. Development and initial validation of myositis activity and damage indices in patients with adult onset disease

OBJECTIVE

To devise new tools to assess activity and damage in patients with idiopathic myopathies (IIM).

METHODS

An international multidisciplinary consensus effort to standardize the conduct and reporting of the myositis clinical trials has been established. Two tools, known as the myositis intention to treat index (MITAX) and the myositis disease activity assessment visual analogue scale (MYOACT), have been developed to capture activity in patients with IIM. In addition, the myositis damage index (MDI) has been devised to assess the extent and severity of damage developing in different organs and systems. These measures have been reviewed by the myositis experts participating in the International Myositis Assessment and Clinical Studies (IMACS) group and have been found to have good face validity and to be comprehensive. The instruments were assessed in two real patient exercises involving patients with adult dermatomyositis and inclusion body myositis.

RESULTS

The reliability of MITAX, MYOACT and MDI, measured by the intraclass correlation coefficient among the physicians, and the inter-rater reliability, as assessed by variation in the physicians' rating of patients, was fair to good for most aspects of the tools. Reliability and inter-rater agreement improved at the second exercise after the participants had completed additional training.

CONCLUSIONS

The MITAX, MYOACT and MDI tools, which are now undergoing validity testing, should enhance the consistency, comprehensiveness and reliability of disease activity and damage assessment in patients with myositis.

Proposed preliminary core set measures for disease outcome assessment in adult and juvenile idiopathic inflammatory myopathies

In order to develop a preliminary core set of disease outcome measures for use in clinical trials of idiopathic inflammatory myopathies (IIM), we evaluated those measures used in previous trials, assessed the validation of published instruments and discussed these at an international consensus conference. The initial proposals were further refined by a multidisciplinary group of adult and paediatric specialists experienced in IIM using the Delphi method. The proposed preliminary core set of disease activity measures consists of five domains: physician and patient/parent global assessments of disease activity; muscle strength; physical function; serum activity of muscle enzymes; and an assessment tool to capture extra-skeletal muscle disease activity. The group recommended further development of a core set of disease damage measures for assessment of persistent changes in anatomy, pathology and function of at least 6 months' duration. The group recommended that patient-reported outcomes should include generic health-related quality of life assessments using the Medical Outcomes Study 36-item Short Form (SF-36) health survey in adult IIM patients and a validated quality of life instrument for paediatric patients. We propose the core set of outcome measures as a minimum group of assessments to include in all IIM therapeutic studies. The use of this core set should assist in standardizing outcome measurement and in optimizing therapeutic trials in myositis.

A dose-response analysis of methoxychlor-induced alterations of reproductive development and function in the rat

In the present study rats were dosed from weaning, through puberty and gestation, to Day 15 of lactation with methoxychlor at 25, 50, 100, or 200 mg/kg/day. Morphological landmarks of puberty were measured, including the ages at vaginal opening, first estrus, and first estrous cycle in females and at preputial separation in males. In the female, estrous cyclicity, fertility, litter size, number of implantation sites, organ weights, and ovarian and uterine histology were also measured. The viability of the offspring (F1) and their fertility were evaluated using a continuous breeding protocol. Males were necropsied after breeding, the reproductive organs were weighed, and the cauda epididymal sperm counts were determined. One testis was used for histopathology, while the other was used to quantify interstitial fluid (IF) content, IF testosterone concentration, and testicular sperm production. Testosterone and androgen-binding protein were measured in the caput epididymis, and sperm motility and morphology were evaluated from a caudal sample. The serum and pituitary were saved for hormonal determinations. Methoxychlor accelerated the age at vaginal opening and first estrus, and the vaginal smears were cornified. Growth was retarded at 100 and 200 mg/kg/day and fertility was reduced when the females were bred with untreated or similarly treated males. In the highest-dose group, the mated females went from constant estrus into pseudopregnancy following mating, but they had no implants. In males, methoxychlor treatment markedly reduced growth, seminal vesicle weight, cauda epididymal weight, caudal sperm content, and pituitary weight. Puberty was delayed in the two highest-dosage groups. Testicular sperm measures were much less affected than caudal measures. Testis weight and histology were slightly affected, and testicular sperm production, sperm morphology, and motility were unaffected. Endocrine function of the testes and pituitary was altered by methoxychlor administration. Leydig cell testosterone production, in response to human chorionic gonadotropin challenge, was reduced and pituitary levels of prolactin, thyroid-stimulating hormone (TSH), and follicle-stimulating hormone (FSH) were altered. In contrast, serum levels of prolactin, FSH, and luteinizing hormone were unaffected. Serum TSH was reduced by 50% of control at 100 and 200 mg/kg/day, while pituitary levels were increased. Gonadotropin-releasing hormone concentration in the mediobasal hypothalamus was also elevated. In spite of the many reproductive alterations, the fertility of treated males was not reduced when they were mated with untreated females.(ABSTRACT TRUNCATED AT 400 WORDS)

Radiosensitization with carboplatin for patients with unresectable stage III non-small-cell lung cancer: a phase III trial of the Cancer and Leukemia Group B and the Eastern Cooperative Oncology Group

PURPOSE

To determine whether the administration of carboplatin concurrently with radiation treatment improves survival in patients with inoperable stage III non-small-cell lung cancer.

PATIENTS AND METHODS

Two hundred eighty-three patients with inoperable stage III non-small-cell lung cancer were entered onto a randomized trial by the Cancer and Leukemia Group B and the Eastern Cooperative Oncology Group. Randomization was performed before initiation of any therapy. All patients received an induction chemotherapy program with vinblastine and cisplatin for 5 weeks, followed by 6,000 cGy of radiation therapy over 6 weeks. One hundred thirty-seven patients were randomized to this therapy regimen alone; 146 patients were randomized to receive carboplatin at 100 mg/m2/wk concurrent with the radiation therapy.

RESULTS

The complete response was 18% with concurrent carboplatin versus 10% with radiotherapy alone (P = .101). There was no difference with respect to failure-free survival (10% with carboplatin and 9% with radiotherapy alone) or overall survival (13% with carboplatin and 10% with radiotherapy alone) at 4 years. In patients not receiving carboplatin, the relapse rate was 69% within the field of radiation and 53% in the boost volume. In patients receiving carboplatin, the relapse rate was 59% within the field of radiation and 43% in the boost volume. Patients with cancers more than 70 cm2 in size had significantly poorer survival (P = .01).

CONCLUSION

Carboplatin at the dose and schedule used did not significantly impact on disease control or survival. The relapse rate within the chest remained more than 50%. More effective regimens will be required to impact on local disease control and survival.

Frequency dependence of the transmission of the EEG from cortex to scalp

Simultaneous recordings of the EEG at subdural and scalp electrodes often show very different activities. Large amplitude activity with maximum power between 15 and 30 c/sec can be often observed on the subdural electrodes together with smaller amplitude lower frequencies, whereas on the scalp only a small part of this high frequency activity is seen and the lower frequencies dominate. The impedance between cortex and scalp has been shown to be similar for low and high EEG frequencies and the high attenuation of the beta activity at scalp electrodes is believed to be due to summation of polyphasic cortical activity. The weighted summation of this polyphasic activity across a limited cortical area (spatial average) is similar to the activity of a non-recursive filter between cortex and scalp and has a low pass characteristic.

Assessment of the association between habitual salt intake and high blood pressure: methodological problems

Despite the finding in cross-cultural comparisons that habitual sodium intake correlates with levels of blood pressure, similar studies from within population groups have yielded inconsistent results. The data presented in this report indicate that in industrialized societies the high degree of intra-individual variability of sodium intake, compared to much smaller inter-individual differences, may obscure potential biological correlations. A quantitative statistical method is presented to assess and minimize the effect of the large intra-individual variation in daily urinary sodium excretion.

Efficacy and safety of adefovir dipivoxil with antiretroviral therapy: a randomized controlled trial

CONTEXT

Adefovir dipivoxil is a nucleotide analog that has demonstrated effective antiretroviral activity against human immunodeficiency virus (HIV) with once-daily administration.

OBJECTIVE

To determine if adefovir confers antiretroviral or immunologic benefit when added to stable antiretroviral therapy.

DESIGN

Multicenter, 24-week, randomized, double-blind, placebo-controlled study. Enrollment was conducted from June 3, 1996, through May 6, 1997.

SETTING

Thirty-three US HIV treatment centers.

PARTICIPANTS

Of 1171 patients screened, 442 patients infected with HIV receiving stable antiretroviral therapy for at least 8 weeks with plasma HIV RNA greater than 2500 copies/mL and CD4+ cell count above 0.20 x 10(9)/L were randomized.

INTERVENTION

Patients were randomized to receive either a single 120-mg/d dose of adefovir dipivoxil (n = 219) or an indistinguishable placebo (n = 223). All patients received L-carnitine, 500 mg/d. Open-label adefovir was offered after 24 weeks and was continued until the end of the study.

MAIN OUTCOME MEASURES

Changes in HIV RNA from baseline, based on area under the curve and CD4+ cell levels, adverse events, and effect of baseline genotypic resistance on response to adefovir.

RESULTS

Patients assigned to adefovir demonstrated a 0.4-log10 decline from baseline in HIV RNA compared with no change in the placebo group (P<.001), which continued through 48 weeks. CD4+ cell counts did not change. During the initial 24 weeks, elevated hepatic enzyme levels (P<.001), gastrointestinal tract complaints (P<.001), and weight loss (P<.001) were associated with use of adefovir. Between 24 weeks and 48 weeks elevations in serum creatinine occurred in 60% of patients, usually returning to baseline after discontinuation of adefovir. Patients with lamivudine or lamivudine and zidovudine resistance mutations demonstrated anti-HIV effects with adefovir (P< or =.01 vs placebo group).

CONCLUSIONS

This study suggests that once-daily adefovir therapy reduces HIV RNA and is active against isolates resistant to lamivudine or lamivudine and zidovudine. Nephrotoxicity occurred when treatment extended beyond 24 weeks but was reversible.

Blood vitamin concentrations during the acute-phase response

OBJECTIVES

To investigate the effect, if any, of the acute-phase response on blood vitamin concentrations and to test the hypothesis that these concentrations may change during stress.

DESIGN

Open study, utilizing a volunteer sample of patients.

SETTING

Tertiary care center.

PATIENTS

Twenty-six healthy adult volunteers (14 female and 12 male); 25 volunteers underwent uncomplicated orthopedic surgery and one suffered traumatic limb fractures.

INTERVENTIONS

None.

MAIN OUTCOME MEASUREMENTS

The presence of a systemic acute-phase response was documented by the determination of serum C-reactive protein concentrations. Blood vitamin concentrations were determined from sequentially collected blood samples over a 7-day period, and compared with entry values.

RESULTS

The presence of the acute-phase response was documented by significant and transient increases in C-reactive protein values. This response was accompanied by significant and transient decreases in the concentrations of leukocyte vitamin C, and in plasma concentrations of vitamin A, retinol-binding protein, vitamin E, total lipids, pyridoxal-5'-phosphate, and albumin. Blood concentrations of pyridoxal-5'-phosphate, retinol-binding protein, and leukocyte vitamin C decreased to values below the respective normal ranges. These concentrations normalized without any therapeutic interventions.

CONCLUSIONS

We demonstrated transient, but significant, decreases in blood vitamin concentrations during the acute-phase response. Recommendations regarding daily supplementation with these vitamins in clinical practice cannot be made on the basis of these results, as the functional importance of these observations is not, at present, clear. However, what is clear is that biochemical vitamin concentrations, determined during the acute-phase response, should be interpreted with care.

Methods to increase response rates to postal questionnaires

BACKGROUND

Postal questionnaires are widely used for data collection in epidemiological studies but non-response reduces the effective sample size and can introduce bias. Finding ways to increase response rates to postal questionnaires would improve the quality of health research.

OBJECTIVES

To identify effective strategies to increase response rates to postal questionnaires.

SEARCH STRATEGY

We aimed to find all randomised controlled trials of strategies to increase response rates to postal questionnaires. We searched 14 electronic databases to February 2003 and manually searched the reference lists of relevant trials and reviews, and all issues of two journals. We contacted the authors of all trials or reviews to ask about unpublished trials. Where necessary, authors were also contacted to confirm methods of allocation used and to clarify results presented. We assessed the eligibility of each trial using pre-defined criteria.

SELECTION CRITERIA

Randomised controlled trials of methods to increase response rates to postal questionnaires.

DATA COLLECTION AND ANALYSIS

We extracted data on the trial participants, the intervention, the number randomised to intervention and comparison groups and allocation concealment. For each strategy, we estimated pooled odds ratios and 95% confidence intervals in a random effects model. Evidence for selection bias was assessed using Egger's weighted regression method and Begg's rank correlation test and funnel plot. Heterogeneity among trial odds ratios was assessed using a chi-square test at a 5% significance level and the degree of inconsistency between trial results was quantified using I(2).

MAIN RESULTS

We found 372 eligible trials. The trials evaluated 98 different ways of increasing response rates to postal questionnaires and for 62 of these the combined trials included over 1,000 participants. We found substantial heterogeneity among trial results in half of the strategies. The odds of response were at least doubled using monetary incentives (odds ratio 1.99, 95% CI 1.81 to 2.18; heterogeneity p<0.00001, I(2)=78%), recorded delivery (2.04, 1.60 to 2.61; p=0.0004, I(2)=69%), a teaser on the envelope - e.g. a comment suggesting to participants that they may benefit if they open it (3.08, 1.27 to 7.44) and a more interesting questionnaire topic (2.44, 1.99 to 3.01; p=0.74, I(2)=0%). The odds of response were substantially higher with pre-notification (1.50, 1.29 to 1.74; p<0.00001, I(2)=90%), follow-up contact (1.44, 1.25 to 1.65; p<0.0001, I(2)=68%), unconditional incentives (1.61, 1.27 to 2.04; p<0.00001, I(2)=91%), shorter questionnaires (1.73, 1.47 to 2.03; p<0.00001, I(2)=93%), providing a second copy of the questionnaire at follow-up (1.51, 1.13 to 2.00; p<0.00001, I(2)=83%), mentioning an obligation to respond (1.61, 1.16 to 2.22; p=0.98, I(2)=0%) and university sponsorship (1.32, 1.13 to 1.54; p<0.00001, I(2)=83%). The odds of response were also increased with non-monetary incentives (1.13, 1.07 to 1.21; p<0.00001, I(2)=71%), personalised questionnaires (1.16, 1.07 to 1.26; p<0.00001, I(2)=67%), use of coloured as opposed to blue or black ink (1.39, 1.16 to 1.67), use of stamped return envelopes as opposed to franked return envelopes (1.29, 1.18 to 1.42; p<0.00001, I(2)=72%), an assurance of confidentiality (1.33, 1.24 to 1.42) and first class outward mailing (1.12, 1.02 to 1.23). The odds of response were reduced when the questionnaire included questions of a sensitive nature (0.94, 0.88 to 1.00; p=0.51, I(2)=0%), when questionnaires began with the most general questions (0.80, 0.67 to 0.96), or when participants were offered the opportunity to opt out of the study (0.76, 0.65 to 0.89; p=0.46, I(2)=0%).

AUTHORS' CONCLUSIONS

Health researchers using postal questionnaires can increase response rates using the strategies shown to be effective in this systematic review.

Validity of age at menarche self-reported in adulthood

OBJECTIVE

To test the validity of age at menarche self-reported in adulthood and examine whether socioeconomic position, education, experience of gynaecological events and psychological symptoms influence the accuracy of recall.

DESIGN

Prospective birth cohort study.

SETTING

England, Scotland and Wales.

PARTICIPANTS

1050 women from the Medical Research Council National Survey of Health and Development, with two measures of age at menarche, one recorded in adolescence and the other self-reported at age 48 years.

RESULTS

By calculating the limits of agreement, kappa statistic and Pearson's correlation coefficients (r), we found that the validity of age at menarche self-reported in middle age compared with that recorded in adolescence was moderate (kappa = 0.35, r = 0.66, n = 1050). Validity was improved by categorising age at menarche into three groups: early, normal and late (kappa = 0.43). Agreement was influenced by educational level and having had a stillbirth or miscarriage.

CONCLUSIONS

The level of validity shown in this study throws some doubt on whether it is justifiable to use age at menarche self-reported in middle age. It is likely to introduce error and bias, and researchers should be aware of these limitations and use such measures with caution.

Coronary arteriography and coronary bypass survey among whites and other racial groups relative to hospital-based incidence rates for coronary artery disease: findings from NHDS

To assess racial differences in health care utilization for coronary artery disease (CAD) the data of the National Hospital Discharge Survey (NHDS) from 1979-84 were examined. Discharge rates for acute myocardial infarction (AMI) were utilized as a measure of hospital-based incidence and relative need for the designated cardiac procedures. Although 35-74 year old Black men had discharge rates of AMI that were 77 per cent of those observed for White men, they underwent coronary arteriography half as often and were only a third as likely to have coronary artery bypass graft (CABG) surgery. Black women in this age range were hospitalized at a slightly higher rate than White women for AMI, yet experienced a 19 per cent lower rate of coronary arteriography and a 52 per cent lower rate of CABG surgery. These data suggest a racial bias in the pattern of care delivered for CAD in US hospitals at the present time.

Hypertension in blacks

The excess of hypertension among blacks has been recognized since early in this century and explains a substantial portion of the black health disadvantage. In a cohort study begun in the 1970s, hypertension accounted for 20% of all-cause mortality among blacks, compared to 10% among whites. National data on trends in hypertension (140/90 mm Hg or treatment) prevalence from 1960 to 1990 suggest a decline from 44% to 32%, although differences in survey technique likely account for this pattern. During this period the prevalence ratio of black:white remained constant at 1.5, suggesting that secular trends in causal factors, if any, effected both groups equally. Recent data demonstrate a gradient in risk across the African diaspora, with standardized prevalences of 14% in West Africa and 26% in the Caribbean, compared to 33% in the US. This pattern parallels the gradient in known risk factors, with obesity alone accounting for a third of the excess in the US compared to Africa. Why the black excess of hypertension in the US? Despite widespread speculation, unique characteristics of hypertension among blacks have yet to be established. Consistent evidence demonstrates a similar impact of the known risk factors in all population groups. Epidemiologic evidence likewise suggests that a similar risk of complications exists with blood pressure elevation among blacks and whites, level for level. Although the genetic epidemiology of hypertension is still in its infancy, no clear cross-population differences are yet apparent. Pathophysiologic traits that are known to be part of the causal etiologic pathway have not been shown to vary across groups. Unique features of this condition among blacks are likely to be restricted to the different mixes and intensities of risk factors. In the absence of evidence to support the hypothesis, it is perhaps surprising that credence continues to be given to the notion of black exceptionalism. Am J

Socioeconomic status and cancer survival

Survival data from eight Cancer and Leukemia Group B (CALGB) protocols were examined for patients with lung cancer (N = 961), multiple myeloma (N = 577), gastric cancer (N = 231), pancreatic cancer (N = 174), breast cancer (N = 87), and Hodgkin's disease (N = 58). After accounting for differences in survival rate attributable to type of cancer, initial performance status, age, and 14 other protocol-specific prognostic indicators, the additional predictive value of socioeconomic status (SES) was evaluated. Race (white v non-white) was not a significant predictor of survival time, but income and education were. People with lower annual incomes (below $5,000 per year in the years 1977 to 1981) and those with lower educational level (grade school only) showed survival times significantly shorter than those with higher income or education, respectively. These survival differences were associated with, but could not be fully explained by, severity of disease at initial presentation. SES continued to exert a small but significant impact on cancer survival, even after controlling for all known prognostic variables. Economically and educationally disadvantaged cancer patients may require treatment programs that include education about treatment and compliance, even after an initial diagnosis is made and treatment is initiated. Because SES is related to survival independent of all known prognostic variables, it should be included in the data bases of clinical trial groups to provide a more accurate test of the effectiveness of new therapies.

The DNA sequence and biological annotation of human chromosome 1

The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome.

Induction of mammary gland development in estrogen receptor-alpha knockout mice

Mammary glands from the estrogen receptor-a knockout (alphaERKO) mouse do not undergo ductal morphogenesis or alveolar development. Disrupted ERalpha signaling may result in reduced estrogen-responsive gene products in the mammary gland or reduced mammotropic hormones that contribute to the alphaERKO mammary phenotype. We report that circulating PRL is reduced in the female alphaERKO mouse. Implantation of an age-matched, heterozygous ERalpha pituitary isograft under the renal capsule of 25-day-old or 12-week-old alphaERKO mice increased circulating PRL and progesterone levels, and induced mammary gland development. Grafted alphaERKO mice also possessed hypertrophied corpora lutea demonstrating that PRL is luteotropic in the alphaERKO ovary. By contrast, ovariectomy at the time of pituitary grafting prevented mammary gland development in alphaERKO mice despite elevated PRL levels. Hormone replacement using pellet implants demonstrated that pharmacological doses of estradiol induced limited mammary ductal elongation, and estradiol in combination with progesterone stimulated lobuloalveolar development. PRL alone or in combination with progesterone or estradiol did not induce alphaERKO mammary growth. Estradiol and progesterone are required for the structural development of the alphaERKO mammary gland, and PRL contributes to this development by inducing ovarian progesterone levels. Therefore, the manifestation of the alphaERKO mammary phenotype appears due to the lack of direct estrogen action at the mammary gland and an indirect contributory role of estrogen signaling at the hypothalamic/pituitary axis.

Divergence of the recent trends in coronary mortality for the four major race-sex groups in the United States

Since 1976 there has been a leveling off or slowdown in the rate of decline in coronary heart disease (CHD) mortality. The age-adjusted absolute annual rate of decline in CHD mortality rates during 1968-75 (delta rate/100,000 population/year) was virtually identical for White males (-7.54), Black males (-7.85), and Black females (-7.20), and somewhat lower for White females (-4.25). During 1976-85, however, the secular trends diverged considerably. Age-adjusted rates continued to decline at the same annual rate for White males, while the decline was approximately half as steep for the other three race-sex groups. During 1976-85 there was also a leveling off in the average annual per cent change in age-adjusted CHD mortality for Black males and females and White females when compared to 1968-75, while there was no change for White males. As a result, more than 40,000 White and Black females and Black males died of CHD in 1985 than would have died if CHD rates would have continued to decline at the 1968-75 trends. All comparisons were based on a reclassification of cause-of-death codes to maximize comparability between the 8th and 9th Revisions of the International Classification of Disease. These results suggest that the factors which have led to the continued decline in coronary heart disease may not have influenced all the demographic groups in this country equally over the last decade.

A note on the biologic concept of race and its application in epidemiologic research

Use of the category of race in epidemiologic research presupposes scientific validity for a system that divides man into subspecies. Although the significance of race may be clear-cut in many practical situations, an adequate theoretical construct based on biologic principles does not exist. Anthropologists have in large measure abandoned the biologic concept of race, and its persistent widespread use in epidemiology is a scientific anachronism. The assumption that race designates important genetic factors in a population is in most cases false. Racial definitions should be seen as primarily social in origin and should be clues to environmental-rather than genetic-causes of disease. An understanding of the social forces leading to racial differentials in health will give further direction to preventive campaigns.

Comparison of intubating conditions after administration of Org 9246 (rocuronium) and suxamethonium

We have assessed intubating conditions after administration of Org 9426 (rocuronium) 600 micrograms kg-1 at 60 or 90 s in groups of 20 patients anaesthetized with thiopentone, nitrous oxide in oxygen and small doses of fentanyl, and compared the data with those obtained after suxamethonium 1 mg kg-1 in similar groups of patients. The influence of prior suxamethonium administration on the potency of Org 9426 was studied also by constructing a dose-response curve. Intubating conditions after Org 9426 were found to be clinically acceptable (good or excellent) in 95% of patients at 60 s and in all patients at 90 s and in all patients at both times after suxamethonium. The average time for the onset of block following Org 9426 at this dose was 89 s (which is shorter than with any of the currently available non-depolarizing neuromuscular blocking drugs); the duration of clinical relaxation (25% recovery of twitch height) 30 min. Prior administration of suxamethonium did not appear to influence the potency of Org 9426.