The Total Ischaemic Burden European Trial (TIBET). Effects of atenolol, nifedipine SR and their combination on the exercise test and the total ischaemic burden in 608 patients with stable angina. The TIBET Study Group

OBJECTIVES

To determine the effects of atenolol, nifedipine and their combination on exercise parameters and ambulatory ischaemic activity in patients with mild chronic stable angina.

SETTING

Multicentre, multinational study involving 608 patients from 69 centres in nine countries.

DESIGN

Placebo washout followed by double-blind parallel-group study comparing atenolol 50 mg bd, nifedipine SR 20 mg bd, and their combination. Patients underwent maximal exercise testing using either a bicycle (n = 289) or treadmill (n = 319) and 48 h of ambulatory ST segment monitoring outside the hospital environment at the end of the placebo washout period and after 6 weeks of active therapy.

RESULTS

Both medications alone and in combination caused significant improvements in exercise parameters and significant reductions in ischaemic activity during daily activities, when compared with placebo. There were, however, no significant differences between groups, for any of the measured ischaemic parameters although combination therapy resulted in a greater fall in resting systolic and diastolic blood pressure than either treatment alone.

CONCLUSIONS

In the management of mild chronic stable angina there appears to be little advantage gained from using combination therapy for ischaemia reduction.

Total Ischaemic Burden European Trial (TIBET). Effects of ischaemia and treatment with atenolol, nifedipine SR and their combination on outcome in patients with chronic stable angina. The TIBET Study Group

OBJECTIVE

To study the relationship between presence or absence of ischaemic events on Holter monitoring and occurrence of a hard or hard+soft endpoint.

DESIGN

A randomized double-blind parallel group study of atenolol, nifedipine and their combination, with ambulatory monitoring off-treatment and after 6 weeks of randomized treatment and prospective follow-up of 2 years on average.

SETTING

Europe.

SUBJECTS

682 men and women with a diagnosis of chronic stable angina and who were not being considered for surgery.

MAIN OUTCOME

Hard endpoints were cardiac death, nonfatal myocardial infarction and unstable angina; soft endpoints were coronary artery bypass surgery, coronary angioplasty and treatment failure.

RESULTS

The study showed no evidence of an association between the presence, frequency or total duration of ischaemic events on Holter monitoring, either on or off treatment, and the main outcome measures. There was a non-significant trend to a lower rate of hard endpoints in the group receiving combination therapy. Compliance, as measured by withdrawal from trial medication, was clearly poorest in the nifedipine group with similar withdrawal rates in the atenolol and combination therapy groups.

CONCLUSION

The recording of ischaemic events in 48 h Holter monitoring failed to predict hard or hard+soft endpoints in patients with chronic stable angina.

Aspirin and NSAID use in older women: effect on bone mineral density and fracture risk. Study of Osteoporotic Fractures Research Group

Prostaglandin inhibition by aspirin or nonsteroidal anti-inflammatory drug (NSAIDs) may inhibit bone loss and preserve bone mineral density (BMD) in vitro and in animal models. The effect of these agents on BMD and fracture risk in postmenopausal women in unknown. We assessed the risk factors for osteoporosis and the use of aspirin and NSAIDs in 7786 white women over age 65. Axial BMD was measured at the same time, and fractures were prospectively documented over the subsequent 4 years of follow-up. In age-adjusted analyses, daily use of aspirin or NSAIDs was associated with a 2.3-5.8% increase in BMD of the hip and spine. The relationship persisted even after adjustment for weight, a variety of medications, self-reported arthritis, and for radiographic findings of osteoarthritis, but the multiply adjusted increase in BMD was only 1.0-3.1%. Fracture risk was similar among daily users of aspirin and NSAIDs and nonusers. After adjustment for potential confounders, among daily aspirin users the relative risk of hip fracture was 1.1 (95% confidence interval [CI]: 0.7, 1.6), and among daily NSAID users the risk was 0.9 (CI: 0.6, 1.4). Considering all nonspine fractures together, the risk among aspirin users was 1.0 (CI: 0.8. 1.2), and among NSAID users the risk was also 1.0 (CI; 0.8, 1.2). Regular use of aspirin or NSAIDs may have a modest beneficial effect on BMD in postmenopausal women. This effect persists after adjustment for obesity and the presence of osteoarthritis. However, among women who take aspirin or NSAIDs regularly, there is no clinically significant protective effect on the subsequent risk of fractures.

Flavoprotein structure and mechanism. 8. Structure-function relations for old yellow enzyme

The past 5 years have seen tremendous progress in our knowledge of old yellow enzyme (OYE) as a number of OYEs have been cloned and expressed, a high-resolution crystal structure has been determined for one of these, and new substrates have been found that can be turned over by the enzyme. Together these studies do not yet define the physiological role of OYE, but they lead to significant new insights into the enzymatic properties and structure-function relations of OYE.

Does the exercise protocol matter when assessing the anti-anginal effects of drug therapy?

Four exercise test protocols (Bruce, Balke, Ellestad and Steep) were compared in 16 patients with proven coronary artery disease in demonstrating the anti-anginal effects of sublingual glyceryl trinitrate in a randomization double-blind trial. Glyceryl trinitrate significantly improved the time, heart rate and rate pressure product to peak exercise, onset of angina and 1 mm ST segment depression in all four protocols (P < 0.05) (except rate pressure product to angina in the Balke protocol). The increase in exercise time was greatest for the Balke protocol at peak exercise (188.1 +/- 187.1) (mean +/- SD in s), at onset of angina (251.9 +/- 247.1) and at 1 mm ST depression (233.6 +/- 243.8), followed by the Steep and Bruce protocols, and was lowest for the Ellestad protocol 41.9 +/- 42.4, 96.5 +/- 65.8, 82.6 +/- 74.0, respectively. Increase in time to peak exercise with glyceryl trinitrate was significantly greater for the Balke protocol in comparison with the other three protocols and for the Bruce and Steep protocols when compared to the Ellestad protocol. Time to 1 mm ST depression with treatment was significantly greater on the Balke and Bruce protocols than the Ellestad protocol, and to onset of angina for the Balke compared to other three protocols. There were no significant differences between the Bruce and Steep protocols for any of the endpoints. The magnitude of treatment effect in the different protocols was accompanied by correspondingly greater inter-patient variability such that no protocol was more, or less, sensitive than another in detecting treatment effect. Changes in heart rate and rate pressure product with treatment were generally similar between the different protocols. In conclusion, a protocol with small and frequent increments (Balke), although able to show greater increase in exercise duration with glyceryl trinitrate than more aggressive protocols, is no more sensitive at detecting treatment effect.

Radial and ulnar cortical thickness of the second metacarpal

Differential bone mass at various skeletal sites, which may be due to mechanical stress exerted by the muscles attached to the bone, has been demonstrated for athletes who exert one limb more than the other. The question arises as to whether this bilateral asymmetry extends to the two sides of the same bone with different muscular attachments. The objectives of this study were to ascertain whether the radial and ulnar sides of the second metacarpal have similar cortical thickness and determine if bone mass decreases equally with age on the radial and ulnar sides. Hand-wrist radiographs were obtained from 201 male and 191 female Caucasian participants of the Baltimore Longitudinal Study of Aging. Differences between radial and ulnar cortical thickness within age groups were tested with Student's t-test and between age groups using analysis of variance. RAdial cortical thickness of the second metacarpal was found to be 11-12% greater in men and 10-12% greater in women than ulnar cortical thickness in both the left and right hands. Age-related changes in radial cortical thickness were evident in both sexes. In men, radial cortex decreased linearly from age 40 to 89. For women, there was a sharp decline in radial thickness from age 50 to age 60. Ulnar cortical thickness declined from age 50 to 60 for women only. Muscle attachment along the radial length of the second metacarpal may influence the accumulation of bone mass on the radial side at younger ages while muscle disuse may precipitate the loss of bone preferentially from the radial side.

Hip and calcaneal bone loss increase with advancing age: longitudinal results from the study of osteoporotic fractures

It is uncertain whether or how rapidly elderly women continue to lose bone with advancing age. To determine rates of change in bone mass at the hip and at the calcaneus in elderly women and to compare these rates of change among estrogen users and nonusers, we prospectively measured rates of change in bone mineral density (BMD) at the total hip and its four subregions (mean +/- SD, 3.55 +/- 0.29 years between examinations) and at the calcaneus (mean +/- SD, 5.69 +/- 0.33 years between examinations) in 5689 community-dwelling white women aged 65 years or older at the baseline examination. The rate of decline in total hip BMD steadily increased from 2.5 mg/cm 2/year (95% confidence interval 2.0 to 2.9) in women 67-69 years old to 10.4 mg/cm 2/year in those aged 85 or older (95% confidence interval 8.4 to 12.4). The rate of bone loss also increased with aging at all subregions of the hip and at the calcaneus. The average loss of bone from the total hip is sufficient to increase the risk of hip fracture by 21% per 5 years in women aged 80 years or older. Compared with nonusers, current estrogen users had a 33% lower age-adjusted mean rate of loss at the total hip (2.9 vs 4.3 mg/cm 2/year, p < or = 0.0001) and a 35% lower age-adjusted mean rate of loss at the calcaneus (3.9 vs 6.0 mg/cm 2/year, p < or = 0.0001). The rate of bone loss in the hip and calcaneus steadily increases with advancing age in older women. Estrogen therapy may significantly decrease this loss. Efforts to understand and prevent bone loss should include elderly women.

Acute effect of oestrogen replacement therapy on treadmill performance in postmenopausal women with coronary artery disease

The significant reduction in cardiovascular morbidity and mortality following oestrogen replacement therapy in postmenopausal women is only partly explained by an improved lipid profile. Given acutely, oestradiol causes vasodilatation and increases coronary blood flow and, in large doses, improves treadmill performance in postmenopausal women with coronary artery disease. However, the significance of oestrogen-mediated vasodilatation is unknown since the acute effects of oestradiol in doses and preparations commonly used clinically have not been tested. The aim of this study was to evaluate the acute effects of conventional replacement therapy with 17 beta-oestradiol on treadmill performance in 16 postmenopausal women with angina in a randomized, double-blind, placebo-controlled cross-over trial. Following baseline treadmill testing a transdermal oestrogen patch releasing 50 micrograms oestradiol. 24 h-1 or matching placebo was applied and the exercise test repeated 24 h later. The patch was then removed. Seven to 14 days later the sequence was repeated using the alternative patch. The changes in time to angina, time to 1 mm ST segment depression and total exercise time for each treatment compared with the corresponding baseline test were calculated. Plasma 17 beta-oestradiol increased with active therapy from 56 +/- 30 pmol.l-1 to 204 +/- 90 pmol.l-1, indicating adequate replacement. Compared with their respective baseline exercise tests there were no differences between active and placebo patches for time to angina (active: 13 +/- 55 s vs placebo: 10 +/- 47 s), time to 1 mm ST segment depression (active: -30 +/- 52 s vs placebo: 24 +/- 71 s) or total exercise time (active: 14 +/- 45 s vs placebo: 13 +/- 35 s). Despite the recognized acute vasodilator action of larger doses of oestrogen, doses conventionally used in hormone replacement therapy had no acute effect on treadmill performance in this group of postmenopausal women with coronary artery disease.

Significant differences between side-mounted and end-mounted intracoronary Doppler flow probes for the measurement of blood flow velocity

Use of the intracoronary Doppler flow probe is an established method for the assessment of coronary blood flow velocity. The aim of this study was to perform an in vitro comparison of two commonly used Doppler probes, which differ in the location of the piezoelectric crystal (end-mounted vs side-mounted). Blood flow velocity was measured over a wide range of flow rates in a flow simulator using heparinized whole blood. Measurements were made with both Doppler probes assessed in two positions (supported and unsupported) within the tubing. The results were compared with estimated true velocities. Further measurements were made with six side-mounted probes, correcting for the assumed crystal mounting angle and for the angle calculated from magnified images of the individual crystals. Mean velocities for end- and side-mounted probes correlated highly with predicted velocities (all r > or = 0.99), but the side-mounted probes significantly overestimated velocity by > 100%. Estimation of the true crystal mounting angle of the side-mounted probe revealed considerable variability (range 30-42 degrees) and was lower than the recommended angle correction factor of 60 degrees. Velocities corrected for the individual crystal mounting angles agreed more closely with predicted mean velocities. Although both probes are adequate for the assessment of relative changes in flow, the side-mounted probe considerably overestimates mean velocity, which is partly explained by the variable mounting angle of the crystal. The demonstrated limitations of the side-mounted Doppler flow probe in vitro should be considered in undertaking measurement of intracoronary blood flow velocity.

Risk factors for hip fracture in white women. Study of Osteoporotic Fractures Research Group

BACKGROUND

Many risk factors for hip fractures have been suggested but have not been evaluated in a comprehensive prospective study.

METHODS

We assessed potential risk factors, including bone mass, in 9516 white women 65 years of age or older who had had no previous hip fracture. We then followed these women at 4-month intervals for an average of 4.1 years to determine the frequency of hip fracture. All reports of hip fractures were validated by review of x-ray films.

RESULTS

During the follow-up period, 192 women had first hip fractures not due to motor vehicle accidents. In multivariable age-adjusted analyses, a maternal history of hip fracture doubled the risk of hip fracture (relative risk, 2.0; 95 percent confidence interval, 1.4 to 2.9), and the increase in risk remained significant after adjustment for bone density. Women who had gained weight since the age of 25 had a lower risk. The risk was higher among women who had previous fractures of any type after the age of 50, were tall at the age of 25, rated their own health as fair or poor, had previous hyperthyroidism, had been treated with long-acting benzodiazepines or anticonvulsant drugs, ingested greater amounts of caffeine, or spent four hours a day or less on their feet. Examination findings associated with an increased risk included the inability to rise from a chair without using one's arms, poor depth perception, poor contrast sensitivity, and tachycardia at rest. Low calcaneal bone density was also an independent risk factor. The incidence of hip fracture ranged from 1.1 (95 percent confidence interval, 0.5 to 1.6) per 1,000 woman-years among women with no more than two risk factors and normal calcaneal bone density for their age to 27 (95 percent confidence interval, 20 to 34) per 1,000 woman-years among those with five or more risk factors and bone density in the lowest third for their age.

CONCLUSIONS

Women with multiple risk factors and low bone density have an especially high risk of hip fracture. Maintaining body weight, walking for exercise, avoiding long-acting benzodiazepines, minimizing caffeine intake, and treating impaired visual function are among the steps that may decrease the risk.

Bilateral asymmetry in bone weight at various skeletal sites of the rat

BACKGROUND

Morphological and functional asymmetry in the limbs has generally been regarded as a human characteristic that is of genetic or of both genetic and environmental origin. The aim of this study was to determine the presence of lateral dominance in bone weight of the forelimb of the rat.

METHODS

Wistar rats (77) were used, 45 controls and 32 experimental animals, implanted with a steel weight subcutaneously under the right forelimb. Bones examined for bilateral asymmetry in bone weight were the mandibula, the bones of fore- and hindlimbs, calcaneus, and talus of the tarsus. The weight of each dry bone was measured to the nearest milligram.

RESULTS

Significant bilateral asymmetry in the forelimb was evident in male and female rats, with the left side having more bone mass than the right. Bilateral differences were more pronounced in the females than the male rats. Greater asymmetry was evident in the experimental group compared to the control rats.

CONCLUSIONS

These findings demonstrate that asymmetry is present not only in humans, but also in lower animals such as rats. Greater asymmetry in the experimental rat group is indicative of the influence of environmental factors or physical stress on asymmetry. We conclude that genetics might control the development of asymmetry, but physical stress may alter the functional expression of the asymmetry.

Is tubal ligation a risk factor for low bone density and increased risk of fracture?

OBJECTIVE

Osteoporosis is a major women's health problem, because it is responsible for about 1.3 million fractures in the United States each year. Estrogen deficiency is a major risk factor in the pathogenesis of osteoporosis. Recent evidence has indicated that tubal ligation may cause menstrual dysfunction and estrogen deficiency. This study examined the association between tubal ligation and bone mass in a group of elderly postmenopausal women.

STUDY DESIGN

Subjects were 2215 white women > or = 65 years old participating in the Baltimore center of the Study of Osteoporotic Fractures. Bone mineral density of the proximal and distal radius and the calcaneus was measured by single photon absorptiometry. Multiple regression analysis was performed to determine whether tubal ligation had an independent effect on bone density. The effect of tubal ligation on the risk of hip and osteoporotic fractures was estimated by Cox proportional hazards model.

RESULTS

Women who reported a tubal ligation had lower, although not statistically significant, bone density of the radius and calcaneus. The relative risk of hip (1.05, 95% confidence limit 0.84 to 1.32) and osteoporotic fractures (1.01, 0.80 to 1.29) was not significantly increased in women with tubal ligation.

CONCLUSION

We conclude that elderly women who had a tubal ligation have small changes in bone density that are not of sufficient magnitude to increase their risk of osteoporotic fractures.

Old yellow enzyme at 2 A resolution: overall structure, ligand binding, and comparison with related flavoproteins

BACKGROUND

Old yellow enzyme (OYE) was the first flavoenzyme purified, but its function is still unknown. Nevertheless, the NADPH oxidase activity, the flavin mononucleotide environment and the ligand-binding properties of OYE have been extensively studied by biochemical and spectroscopic approaches. Full interpretation of these data requires structural information.

RESULTS

The crystal structures of oxidized and reduced OYE at 2 A resolution reveal an alpha/beta-barrel topology clearly related to trimethylamine dehydrogenase. Complexes of OYE with p-hydroxybenzaldehyde, beta-estradiol, and an NADPH analog show all three binding at a common site, stacked on the flavin. The putative NADPH binding mode is novel as it involves primary recognition of the nicotinamide mononucleotide portion.

CONCLUSIONS

This work shows that the striking spectral changes seen upon phenol binding are due to close physical association of the flavin and phenolate. It also identifies the structural class of OYE and suggests that if NADPH is its true substrate, then OYE has adopted NADPH dependence during evolution.

The interpersonal and psychological functioning of women who experienced childhood physical abuse, incest, and parental alcoholism

Questionnaires assessing childhood physical abuse (CPA), childhood incest (CI), and parental alcoholism (ACOA) were completed by 253 college women from introductory psychology classes at a large midwestern university. The relationship between these variables and the level of depression, self-esteem and involvement with physically abusive, sexually assaultive, sexually coercive, and chemically dependent partners was assessed. Support was found for an additive model of trauma that predicted a relationship between number of childhood traumas and adult outcomes. Limited support was found for a specificity model of trauma that predicted that specific childhood trauma would be predictive of parallel negative adult outcomes.

Comparison of Doppler derived haemodynamic variables and simultaneous high fidelity pressure measurements in severe pulmonary hypertension

OBJECTIVE

To assess relations between right ventricular pressure measured with a high fidelity transducer tipped catheter and the characteristics of tricuspid regurgitation recorded with Doppler echocardiography.

DESIGN

A prospective non-randomised study of patients with severe pulmonary hypertension referred for consideration of lung transplantation.

SETTING

A tertiary referral centre for cardiac and pulmonary disease, with facilities for invasive and non-invasive investigation, and assessment for heart and heart-lung transplantation.

PATIENTS

10 patients with severe pulmonary hypertension being considered for lung transplantation.

ENDPOINTS

Peak right ventricular, pulmonary artery, and right atrial pressures; peak positive and negative right ventricular dP/dt; peak Doppler right ventricular-right atrial pressure drop; Doppler derived peak positive and negative right ventricular dP/dt; and time intervals of Q to peak right ventricular pressure and to peak positive and negative right ventricular dP/dt.

RESULTS

The mean (SD) pulmonary artery systolic pressure was 109 (29) mm Hg. The peak Doppler right ventricular-right atrial pressure drop underestimated peak right ventricular pressure by 38 (21) mm Hg, and by 21 (18) mm Hg when the Doppler value was added to the measured right atrial pressure (P values < 0.05). This discrepancy was greater for higher pulmonary artery pressures. The timing of peak right ventricular pressure differed, with the Doppler value consistently shorter (mean difference 16 ms, P < 0.05). Values of peak positive and negative right ventricular dP/dt and the time intervals Q-peak positive right ventricular dP/dt and pulmonary closure to the end of the pressure pulse differed between the two techniques in individual patients, but not in a consistent or predictable way.

CONCLUSIONS

Doppler echocardiography significantly underestimates the peak right ventricular pressure and the time interval to peak right ventricular pressure in pulmonary hypertension, particularly when severe. These differences may be related to orifice geometry. Digitisation of Doppler records of tricuspid regurgitation provides useful semiquantitative estimates of absolute values and timing of peak positive and negative right ventricular dP/dt. Clinically significant differences may exist, however, and must be considered in individual patients.

Correlates of impaired function in older women

OBJECTIVE

To determine the factors associated with impaired function in older women.

DESIGN

Cross-sectional analysis of baseline data collected for a multicenter, prospective study of risk factors for osteoporotic fractures.

SETTING

Four clinical centers in Portland, Oregon, Minneapolis, Minnesota, Baltimore, Maryland, and the Monongahela Valley, Pennsylvania.

PARTICIPANTS

A total of 9,704 ambulatory, non-black women, aged 65 years and older, recruited from population-based listings.

MEASUREMENTS

Independent variables, including demographic and historical information (medical conditions, health habits, and medications) and physiologic measures (anthropometry, blood pressure, mental status, vision, and neuromuscular performance) were obtained from a baseline questionnaire, interview, and examination. Measurement of function was assessed by self-reported ability to perform six physical and instrumental activities of daily living (ADL) and impaired function (dependent variable) was defined as difficulty performing three or more physical and instrumental ADLs.

RESULTS

In order of decreasing strength of association, hip fracture, osteoarthritis, parkinsonism, slower walking speed, lower hip abduction force, back pain, greater Quetelet index, osteoporosis, former alcohol use, stroke, never drinking alcohol, lower mental status, use of anxiolytics and/or sleeping medications, inability to hold the tandem position, postural dizziness, cataracts, greater waist to hip ratio, lower physical activity in the past year, greater lifetime cigarette consumption, and lower grip strength were independently associated with impaired function in multivariate analyses. Age, low educational level, diabetes, current heavy alcohol use, postural hypotension, depth perception, and contrast sensitivity were not independent predictors. A combination of neuromuscular performance measures, including decreased muscle strength and impaired balance and gait, appeared to account for the effect of age on disability.

CONCLUSION

A combination of many factors, including medical conditions, health habits such as obesity, smoking, alcohol abstinence, and physical inactivity, and direct measures of neuromuscular performance are associated with impaired function in older women.

Chest pain in women: clinical, investigative, and prognostic features

OBJECTIVE

To characterise clinical, investigative, and prognostic features of women referred with chest pain who subsequently underwent coronary angiography.

DESIGN

Analysis of all women with angina referred to one consultant during 1987-91 who subsequently underwent coronary angiography, with follow up to present day.

SETTING

Cardiothoracic centre.

SUBJECTS

Women with normal coronary arteries; women with coronary artery disease shown on angiography; men with coronary artery disease matched for age; men referred with chest pain during the same period subsequently found to have normal coronary arteries.

MAIN OUTCOME MEASURES

Risk factor analysis; results of exercise testing and coronary angiography; intervention; morbidity and mortality.

RESULTS

Women comprised 23% (202/886) of patients referred with chest pain who subsequently underwent angiography. 83/202 women had normal coronary angiograms compared with 55/684 men (41% v 8%, P < 0.01). Diabetes mellitus was the only risk factor more frequently encountered in women with coronary artery disease (P = 0.001). The specificity and positive predictive value of exercise testing before angiography were significantly lower in women than men (71% v 93%, P < 0.001 and 76% v 95%, P < 0.001, respectively). Revascularisation procedures were as common in women with coronary artery disease as in men (81 (68%) v 70 (59%)), and there was no difference in event rate during follow up. Many patients with normal coronary arteries, irrespective of sex, had symptoms during follow up (61 (73%) women, 36 (65%) men) and continued to take antianginal drugs (27 (33%) women, 14 (28%) men); 14 (17%) women and six (11%) men required hospital readmission for severe symptoms.

CONCLUSIONS

In this series, although women comprised the minority of patients referred with chest pain, a diagnosis of normal coronary arteries was five times more common in women than men. Risk factor analysis and exercise testing were of limited value in predicting coronary artery disease in women. There was no sex bias regarding revascularisation procedures, and outcome was similar. A diagnosis of non-cardiac chest pain in patients with normal coronary arteries was of little benefit to the patient with regard to morbidity.

Effect of acadesine, a new metabolic agent, on exercise-induced myocardial ischemia in chronic stable angina

Acadesine, the first of a class of adenosine-regulating agents, has been shown to possess antiischemic properties in animal models. The aim of the study was to assess the effect of acadesine on exercise-induced myocardial ischemia in patients with chronic stable angina pectoris. Twelve patients with stable angina entered a five-way, randomized double-blind study comparing the effects of four doses of acadesine with placebo on time to 1 mm ST-segment depression and other parameters of exercise tolerance. At each study period patients underwent baseline exercise testing, followed by drug or placebo infusion after a 60 minute rest period. The exercise test was repeated after 30 minutes infusion, which continued throughout recovery. Time to angina, time to 1 mm ST depression, and total exercise time during the placebo infusion were 301.1 +/- 45.3, 314.8 +/- 50.9, and 399.4 +/- 47.6 seconds. The placebo-adjusted percentage change in time to 1-mm ST segment with acadesine 6, 12, 24, and 48 mg/kg was -0.1 +/- 6.2%, 11.1 +/- 13.8%, 12.9 +/- 8.6%, and -3.2 +/- 6.8%, respectively (p = NS vs. baseline). Time to angina, total exercise time, and recovery time of the ST segment were not consistently altered by acadesine. The lack of effect across all acadesine doses is consistent with animal data from ischemia-reperfusion injury studies, where a clear dose dependency was present with a loss of effect at higher doses. Alternatively, the extent of ischemia induced by treadmill exercise may have been insufficient for the antiischemic activity of acadesine to be evident.

Crystallization of Old Yellow Enzyme illustrates an effective strategy for increasing protein crystal size

Old Yellow Enzyme (OYE) was the first flavoenzyme discovered, and has been widely used as a model flavoenzyme. Three crystal forms have been grown from natural protease-nicked OYE and one has been grown from intact recombinant OYE. The recombinant OYE crystals are best suited for structure determination and grow from a solution containing polyethylene glycol and MgCl2. They belong to space group P4(3)2(1)2 with unit cell dimensions a = b = 142.88 A, c = 43.01 A and have a single OYE chain per asymmetric unit. In order to optimize the production of large single crystals, we have carried out a systematic study of crystal size versus drop volume. Crystallographic lore holds that the volume of the medium in which the crystals are grown should have a significant effect on the final size of the crystals produced. However, a systematic investigation of the degree to which the volume of the crystallization sample affects the final size of the crystals has not been reported. In order to investigate this phenomenon, drops were set up in both hanging and sandwich geometry at a variety of drop volumes, but otherwise identical crystallization conditions. A 60-fold increase in drop volume produced a 730-fold increase in crystal volume, and a simultaneous increase in the effective diffraction limit of the crystals from near 2.5 A to well beyond 2.0 A resolution. The dramatic crystal volume increase appears to be due both to the increased amount of protein and the slower equilibration rates associated with larger drops. Our results also emphasize that the quality of diffraction data may often be limited by crystal size rather than intrinsic crystal order even in the case of reasonably sized (200 to 400 microns) crystals.

Unstable and stable angina

Treatment of both stable and unstable angina depends on initially defining the pathophysiological mechanisms. The goal of treatment is to prevent the development of angina pectoris and possibly also to improve the prognosis. beta-blockade is effective in treating effort-related angina, as are calcium antagonists, which are also effective in treating coronary spasm. Combination therapy may be synergistic, but evidence to support this is controversial. In unstable angina the main goal of treatment is the prevention of myocardial infarction and death. While calcium antagonists have not been shown to improve the prognosis, there is more evidence to support the use of beta-blockers, particularly in combination with a calcium antagonist. Aspirin and possibly heparin should be considered as routine treatment.

Novel heteronuclear methods of assignment transfer from a diamagnetic to a paramagnetic protein: application to rat cytochrome b5

15N and 1H resonance assignments for backbone and side-chain resonances of both equilibrium forms of rat ferricytochrome b5 have been obtained, using a combination of novel heteronuclear assignment transfer methods from the known assignments of the diamagnetic protein [Guiles, R. D., Basus, V. J., Kuntz, I. D., & Waskell, L. A. (1992) Biochemistry 31, 11365-11375] and computational methods which depend on an accurate determination of the orientation of the components of the susceptibility tensor. The transfer of amide proton resonance assignments takes advantage of the apparent insensitivity of amide 15N resonances to pseudocontact effects, evident in overlays of 15N-1H heteronuclear correlation spectra. Amide-proton resonance assignments tentatively transferred from the known diamagnetic assignments to the paramagnetic form of the protein were confirmed using conventional assignment strategies employing 600-MHz COSY, HOHAHA, and NOESY spectra of the oxidized protein. As was observed in rat ferrocytochrome b5, more than 40% of all residues exhibited NMR detectable heterogeneity due to the two different orientations of the heme. Complete assignment of both forms enabled accurate determination of the orientation of the susceptibility tensor for both conformations of the heme. The orientation of the z-component of the susceptibility tensors for the two forms are indistinguishable, while the in-plane components appear to differ by about 6 degrees. Differences in the orientation of the in-plane susceptibility components are undoubtedly due dominantly to the relative axial rotation of the heme of between 5 degrees and 10 degrees indicated by the NOESY contacts to the protein observed in the spectra of the ferrocytochrome [Guiles, R. D., Basus, V. J., Kuntz, I. D., & Waskell, L. A. (1992) Biochemistry 31, 11365-11375; Pochapsky, T. C., Sligar, S. G., McLachlan, S. J., & LaMar, G. N. (1990) J. Am. Chem. Soc. 112, 5258-5263].

Reproductive correlates of bone mass in elderly women. Study of Osteoporotic Fractures Research Group

Results from previous studies of reproductive factors and bone density have been conflicting; some demonstrate a beneficial effect, but others show a detrimental effect on bone density. The present study investigates the association of parity, lactation, and menstruation with radial bone density in 2230 white women, 65 years of age and older. Bone density was assessed by single-photon absorptiometry. Linear multiple regression was utilized to determine if reproductive factors were associated with radial bone density. The number of births, duration of menstrual bleeding, age at menarche, and years menstruating were significant independent predictors of postmenopausal bone density of the radius. A 1.4% increase in distal radius bone density was observed with each additional birth. Women who began menstruation at age 9 had 6.3% higher bone density than women who began at age 16. Women who menstruated for 3 days during each menstrual cycle had 2.8% less distal radius bone density than women who bled for 7 days. Each decade of menstruation was associated with a 2% greater distal radius bone density. No difference in bone density was demonstrated for women who breast-fed and women who did not. Length of the menstrual cycle, amount of menstrual flow, and irregularity of the menstrual cycle were not significantly associated with radial bone mineral density. In conclusion, pregnancy and menstruation are associated with postmenopausal bone density of the radius.

Atenolol or nicardipine alone is as efficacious in stable angina as their combination: a double blind randomised trial

BACKGROUND

Beta blockers and calcium antagonists are widely used in the management of angina pectoris in the belief that the combination is more efficacious than either drug alone.

METHODS

This double blind randomised crossover placebo controlled study compares the effects of nicardipine, atenolol and their combination in 30 patients with chronic stable angina. Each treatment period lasted 6 weeks with dose titration after 3 weeks. Symptom limited treadmill exercise testing and radionuclide ventriculography at rest was carried out at the end of each treatment period.

RESULTS

Total exercise duration and time to 1-mm ST-segment depression was significantly prolonged by nicardipine and atenolol when compared to placebo, the combination offered no additional benefit. Time to onset of angina was significantly prolonged by nicardipine and the combination but not by atenolol. Indices of left ventricular function were not significantly affected by any treatment other than an increase in left ventricular end diastolic volume on atenolol and the combination.

CONCLUSIONS

Nicardipine and atenolol are equally effective in prolonging exercise duration and time to onset of ischemia in patients with chronic stable angina while the combination appeared to offer no additional benefit. Nicardipine prolonged the time to onset of angina significantly; again there was no further improvement with the combination. Neither drug appears to have an important effect on the parameters of diastolic function studied in patients with chronic stable angina.

Clinical trials in silent ischaemia: lessons from TIBET

The Total Ischaemic Burden European Trial (TIBET) affords the opportunity to investigate the prognostic value of both exercise testing and ambulatory monitoring on and off medical treatment; 682 patients were followed for two years. Patients with < 1 mm ST segment depression on exercise testing have very low risk indeed of an important end point in a two year period, and this effect is partially obscured by the presence of medical treatment. Ambulatory monitoring showed that the presence of silent ischaemia had little prognostic impact in this group of patients.

Adjustable Silicone Gastric Banding vs Vertical Banded Gastroplasty: a comparison of early results

The Kuzmak adjustable silicone gastric band (ASGB; 33 patients) and the vertical banded gastroplasty (VBG; 91 patients) are compared for weight loss, complication rates, and patient satisfaction. The complexity of the two operations is also compared, using operative time, blood loss, and length of hospitalization. When these three parameters were evaluated, the operations were remarkably similar, although a significant percentage of the ASGB patients left the hospital earlier than the VBG patients. The ASGB group of patients lost 52% of their excess weight (34 kg) and the VBG group 63% (40 kg), with the maximum follow-up being 15 months. Mechanical problems (leaks in the system) occurred in four ASGS patients. This slowed their weight loss and caused dissatisfaction with the procedure. Sixty-four percent of the patients underwent adjustment of the silicone band at least once during the 15 months. Complications included stomal stenosis in 9% of the ASGB patients vs 1.3% in the VBG patients. There was one staple-line leak, one subphrenic abscess (without a leak), and one retrogastric hematoma in the VBG patients. One death occurred in the ASGB group in a patient who was found at surgery to have unanticipated post-hepatitic cirrhosis. There were no deaths in the VBG group. The conclusion reached is that the ASGB compares favorably with the VBG as a bariatric surgical procedure.

Low frequency oscillations in pulmonary arterial pressure in chronic heart failure

Spontaneous, sustained low frequency oscillations of pulmonary arterial pressure were observed in 8 patients with moderate to severe chronic heart failure during recordings of pulmonary arterial pressure of 8.6 to 48 hours duration. The oscillations (frequency range 0.015 to 0.035 Hz) had a distinct peak from and lower frequency range than respiration (0.2 to 0.6 Hz) and heart rate (0.8 to 1.9 Hz). They were present from 42% to 82% of the recording time with an amplitude varying from undetectable to a maximum range from 5.3 mm Hg to 19.7 mm Hg. When detectable, the mean amplitude of the low frequency oscillations of pulmonary arterial pressure ranged from 1.2 +/- 1.2(SD) mm Hg to 4.3 +/- 3.3 mm Hg. These oscillations are lower in frequency than the low frequency component usually described in recordings of systemic arterial pressure and heart rate in normal subjects, and are closer to the very low frequency rhythms described in severe chronic heart failure and Cheyne Stokes respiration.

Lack of rebound during intermittent transdermal treatment with glyceryl trinitrate in patients with stable angina on background beta blocker

OBJECTIVE

To assess whether intermittent transdermal treatment with glyceryl trinitrate causes clinically significant rebound in patients maintained on beta blockers for stable angina pectoris.

DESIGN

Serial treadmill exercise testing in a double blind, randomised, placebo controlled cross over trial. Baseline exercise testing was performed at 0900 and 1100 at visit 1. Transdermal glyceryl trinitrate patches releasing 15 mg/24 h were applied at 2200 the evening before visits 2 and 3, and exercise testing was performed at 0900 the next morning. The patch was removed and replaced with either an identical patch or matching placebo and exercise tests were repeated two hours later. The alternative treatment was given at visit 3.

SETTING

Tertiary referral centre.

PATIENTS

14 patients with stable angina pectoris maintained on beta blocker treatment alone.

MAIN OUTCOME MEASURES

Time to angina, 1 mm ST segment depression, and total time, together with heart rate, systolic blood pressure, and rate-pressure product.

RESULTS

Active treatment improved treadmill performance at 0900 and 1100. Time to angina, time to 1 mm ST segment depression, and total time fell significantly on placebo compared with the 0900 exercise test on active treatment, but were not significantly different to the baseline exercise test either.

CONCLUSIONS

Intermittent transdermal treatment with glyceryl trinitrate is not associated with the rebound phenomenon in patients maintained on beta blockers for stable angina pectoris.

Long term follow up of severely ill patients who underwent urgent cardiac transplantation

OBJECTIVE

To assess long term survival (> 5 years) and quality of life in severely ill patients referred for urgent cardiac transplantation.

SETTING

Tertiary referral centres: before transplantation at the National Heart Hospital (late 1984 to end 1986); after transplantation at Harefield Hospital.

SUBJECTS

Eighteen patients (15 men; three women) who had required intensive support in hospital before cardiac transplantation and were alive at short term follow up.

INTERVENTIONS

Intravenous infusions of cardiac drugs (mean 2.2 infusions), intravenous diuretics (17 patients), and many other drugs before transplantation. Intra-aortic balloon counterpulsation (four patients), temporary pacing (two), and resuscitation from cardiac arrest (three). Patients had specialised nursing care on a medical intensive care unit in almost every case.

MAIN OUTCOME MEASURES

Long term survival in patients after urgent cardiac transplantation and perceived quality of life.

RESULTS

Of 18 patients who were alive at short term follow up (mean (range) 19.4 (10-33) months), 14 were still alive in 1992 (69 (61-83) months). Ten still worked full time, and 11 reported no restrictions in their daily activities. Three of four patients who died in the intervening period survived > 5 years after transplantation. Overall, 17 of 18 patients survived at least 5 years.

CONCLUSIONS

In severely ill patients who undergo urgent cardiac transplantation and survive in the short term, long term (5-7 year) survival and quality of life seem good.

Ambulatory blood pressure monitoring and circadian variation of cardiovascular disease; clinical and research applications

Ambulatory blood pressure monitoring is an evolving technology. It has an established role in the diagnosis of hypertension, the clinical management of selected patients, and in the evaluation of new medication. From continuous recording much has been learned about the circadian nature of blood pressure and heart rate. Future research holds promise for a greater understanding of the mechanisms and treatment of cardiovascular disease. The purpose of this short review is to describe the development of ambulatory blood pressure monitoring, and outline some of its important contributions to date; and also to explore the research potential and clinical utility of advanced intravascular monitoring techniques, such as the continuous recording of pulmonary artery pressure in ambulant patients.

A new system for ambulatory pulmonary artery pressure recording

OBJECTIVE

To develop a complete system for the measurement, recording, and analysis of ambulatory pulmonary artery pressure.

DESIGN

The new system consists of a pulmonary artery catheter, an ambulatory recorder, and a desktop computer. Pulmonary artery pressure is measured by a micromanometer tipped catheter with an in vivo calibration system to allow correction for zero drift. This catheter is plugged into a small battery powered recorder. The recorder has two input channels, one for pressure and one for an event marker. The pressure wave is sampled 32 times/s, processed by an in built computer, compressed, and stored in semi-conductor memory. On completion of a recording, data is transferred from the ambulatory recorder through a serial data link to an Acorn Archimedes desktop computer on which further data processing, statistical analysis, graphics, and printouts can be obtained.

RESULTS

The system has been used in 18 patients, with technically successful recording in 14, less than 15 minutes of data loss in three, and 12 hours of data loss in one.

CONCLUSIONS

A new system for ambulatory pulmonary artery monitoring has been developed and used clinically with success. It may provide new perspectives on the pathophysiology of disease as it applies to everyday life.

Purification and characterization of a novel enoyl coenzyme A reductase from Streptomyces collinus

A novel NADPH-dependent enoyl reductase, catalyzing the conversion of 1-cyclohexenylcarbonyl coenzyme A (1-cyclohexenylcarbonyl-CoA) to cyclohexylcarbonyl-CoA, was purified to homogeneity from Streptomyces collinus. This enzyme, a dimer with subunits of identical M(r) (36,000), exhibits a Km of 1.5 +/- 0.3 microM for NADPH and 25 +/- 3 microM for 1-cyclohexenylcarbonyl-CoA. It has a pH optimum of 7.5, is most active at 30 degrees C, and is inhibited by both divalent cations and thiol reagents. Two internal peptide sequences were obtained. Ansatrienin A (an antibiotic produced by S. collinus) contains a cyclohexanecarboxylic acid moiety, and it is suggested that the 1-cyclohexenylcarbonyl-CoA reductase described herein catalyzes the final reductive step in the conversion of shikimic acid into this moiety.

Biosynthesis of ansatrienin by Streptomyces collinus: cell-free transformations of cyclohexene- and cyclohexadienecarboxylic acids

Cell-free extracts of Streptomyces collinus were tested with various cyclohexene- and cyclohexadienecarboxylic acids in order to determine the latter stages of the conversion of shikimic acid to cyclohexanecarboxylic acid. It was demonstrated that the final three steps of this process involve reduction of the alpha,beta-double bond of 1(6),2-cyclohexadienylcarbonyl CoA, an isomerization of the double bond of the resulting 2-cyclohexenylcarbonyl CoA to afford 1-cyclohexenylcarbonyl CoA, and a subsequent reduction of the newly formed alpha,beta-double bond. Both of the reduction steps were shown to require NADPH as a cofactor.

Value of ambulatory ST segment monitoring in patients with chronic stable angina: does measurement of the "total ischaemic burden" assist with management?

OBJECTIVE

To assess the prognostic significance of transient ischaemic episodes during daily activities in patients with stable angina.

PATIENTS AND METHODS

172 patients with stable angina attending the cardiac outpatients departments of Hillingdon Hospital (n = 155) and the National Heart Hospital (n = 17) were prospectively studied by exercise testing and 48 hours of ambulatory ST segment monitoring, and followed for prognostic purposes for up to 39 months (mean 24.5 months). Patient inclusion depended on a clinical diagnosis of stable coronary artery disease which necessitated outpatient review (and antianginal treatment in 94% of patients). It was not dependent on objective evidence of reversible ischaemia. Events recorded during the follow up period included death, non-fatal myocardial infarction, unstable angina, and the requirement for revascularisation.

RESULTS

72 patients (42%) had transient ischaemic episodes during daily activities, and 104 patients (60.5%) had an ischaemic response to exercise. 63 patients (36%) had evidence of ischaemia on both investigations; with 59 (34%) having no documented ischaemia on either investigation. There were 27 patient events (15.7%) recorded over a mean 24.5 month follow up, including five deaths (2.9%) (three cardiac related (1.7%)), six non-fatal myocardial infarctions (3.5%), six admissions with unstable angina (3.5%), and 10 revascularisation procedures (5.8%). Of the nine "hard" or objective end points (cardiac death and non-fatal myocardial infarction), only two had evidence of transient ischaemia on ambulatory ST segment monitoring at initial investigation, with 10 of the 25 patients (38.5%) with any cardiac event having such episodes.

CONCLUSIONS

The outcome in patients with chronic stable angina receiving standard medical treatment was good over a mean two year follow up period. For the purpose of assessing prognosis over this time scale, there was no advantage to performing ambulatory ST segment monitoring in such patients.

The influence of right heart catheterisation on pulmonary arterial pressure in chronic heart failure: relationship to neuroendocrinal changes

Continuous ambulatory measurement of pulmonary arterial pressure was used to investigate changes following right heart catheterisation in patients with chronic heart failure. Ten males, mean age 56 years, with chronic heart failure, underwent 24 hour pressure recording using a micromanometer tipped catheter with in vivo calibration and frequency modulated recording. Eight patients were taking diuretics and 3 vasodilators. Blood was drawn for catecholamines, plasma renin activity and atrial natriuretic peptide 1 hour before catheterisation (-1 h), at the time of catheterisation (0 h) and 1, 2, 3, 4 and 6 hours later and aldosterone, cortisol and growth hormone at -1, 0 and 6 hours. Analysis of variance was used to determine changes in pulmonary arterial pressure, heart rate and hormones from the time of catheterisation in lying, sitting and standing postures. There was no significant change in pulmonary arterial pressure or heart rate over the 12 hours following or 24 hours after catheterisation in any posture. In the majority of patients plasma noradrenaline, plasma renin activity, atrial natriuretic peptide, aldosterone and cortisol were elevated. There was no significant change in hormone levels during the 6 hours following catheterisation. These findings suggest that the effect of invasive haemodynamic monitoring and chronic medical therapy on central haemodynamics is minor, and that a delay between insertion of catheters and measurement of pressure is unnecessary.

Avoidance of tolerance and lack of rebound with intermittent dose titrated transdermal glyceryl trinitrate. The Transdermal Nitrate Investigators

OBJECTIVES

To investigate the efficacy of transdermal glyceryl trinitrate given continuously and with a nocturnal nitrate free period.

DESIGN

Double blind placebo controlled study with two parallel limbs.

SETTING

Multicentre trial.

PATIENTS

52 patients randomised to receive either continuous treatment (23 patients) or intermittent treatment with an individually titrated dose (29 patients) for 14 days: both treatments were compared with placebo in a cross-over fashion.

INTERVENTION

Continuous treatment with 10 mg per 24 hours of transdermal glyceryl trinitrate or intermittent transdermal glyceryl trinitrate titrated to give an arbitrary 10 mm Hg drop in systolic blood pressure (mean dose 18.2 mg) given over approximately 16 hours.

MAIN OUTCOME MEASURE

Treadmill exercise stress testing and ambulatory monitoring of the ST segment after 14 days' treatment.

RESULTS

After 14 days' intermittent treatment resting supine and standing systolic blood pressure fell by 7.5 mm Hg (95% confidence interval 2.7 to 12.2) and 9.0 mm Hg (95% CI 3.4 to 14.5) respectively (p less than 0.01); resting heart rate was unchanged. Mean heart rate at 1 mm ST segment depression rose by 11.9 beats/min (CI 1.1 to 23.7) (p less than 0.05), mean time to onset of angina increased by 59 seconds (CI 10.8 to 108) (p less than 0.05), and total exercise duration increased by 40 seconds (p less than 0.05). These changes were not seen after continuous treatment. The frequency of ischaemic episodes was not reduced with either regimen nor was the circadian distribution of these episodes altered, in particular nocturnal episodes did not increase during intermittent treatment.

CONCLUSION

Tolerance to glyceryl trinitrate was avoided by the use of individually titrated doses administered with a nocturnal nitrate free period. There was no evidence of "rebound" on ambulatory monitoring during this treatment.

Double-blind randomised placebo-controlled dose-efficacy study of sustained release verapamil in chronic stable angina

The efficacy and tolerability of sustained release verapamil (Securon SR) was investigated in twenty-four patients with chronic stable angina. Patients entered four randomised, double-blind treatment periods, each lasting one week of verapamil-SR 240 mg once daily, 360 mg once daily, 240 mg twice daily, and matching placebo. Four patients were withdrawn, but in one instance this was attributable to side effects from verapamil. Among the remaining twenty patients, mean frequency of angina fell from 4.25 episodes during the last five days of placebo to 2.35, 2.6 and 1.3 episodes during respective active treatments (all P less than 0.001). Compared with placebo the median percentage increase in time to 1 mV ST depression during treadmill exercise (12 hours post dose) was significant only with the regimen of verapamil-SR 240 mg given twice daily at +11% (P = 0.04). Total duration of exercise was also significantly longer and maximum ST depression significantly less only with the twice daily treatment (704 + 186 sec vs 648 + 203 sec; P = 0.03, and 1.75 + 0.73 mm vs 2.15 +/- 0.62 mm; P = 0.02). Side effects, predominantly constipation, breathlessness, and swollen ankles, occurred most frequently with verapamil-SR 360 mg. Thus, sustained release verapamil is well tolerated and effective in the treatment of angina. A regimen of 240 mg given twice daily emerges as superior to once daily treatments for 24-hour prophylaxis of angina.

Therapeutic implications of dynamic coronary stenosis in patients with single vessel coronary artery disease

Ten patients with proven single-vessel coronary artery disease and a positive exercise test for ischaemia were investigated to establish the importance and therapeutic implications of dynamic coronary stenosis in such patients. All patients interrupted their anti-anginal therapy and under took serial exercise testing in an attempt to identify variability in the ischaemic threshold. Ergonovine testing was performed in nine patients and all underwent 48 h of ambulatory ST segment monitoring while treatment was discontinued. Patients then entered a randomized double-blind study of atenolol and nifedipine; treadmill exercise testing and 48 h of ambulatory ST segment monitoring were performed at the end of each treatment phase. Six (60%) patients showed evidence of variability in coronary vasomotor tone four of whom developed significant ST segment changes during administration of ergonovine; a further two had greater than 30% variability in time to onset of ischaemia during serial treadmill exercise testing. Atenolol significantly increased the time to ischaemia on exercise testing, both in the group as a whole and in the subgroup with evidence of altered vasomotor tone when compared with no therapy, and led to a non-significant reduction in the frequency and duration of ischaemia during the patients' daily lives. Nifedipine, conversely, did not significantly increase time to ischaemia on exercise testing or reduce the frequency or duration of ambulatory ischaemia in either the whole group or the subgroup. With evidence of altered vasomotor tone when compared to no therapy however it was beneficial in terms of reduction in chest pain and requirement for glyceryl trinitrate during daily life.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of 3-carbamoylecgonine methyl ester analogues as inhibitors of cocaine binding and dopamine uptake

Five (1R-2-exo-3-exo)-3-(N-phenylcarbamoyl)ecgonine methyl ester analogues were synthesized and characterized by 1H and 13C NMR, IR, and thermospray MS. The compounds were synthesized in two or three steps as (-)-stereoisomers from (-)-ecgonine in good yield (56% overall). These cocaine derivatives were assessed for their ability to inhibit [3H]cocaine binding to rat striatal tissue and to inhibit [3H]dopamine uptake into synaptosomes prepared from the same tissue. The most potent of the analogues was (1R-2-exo-3-exo)-2-(carbomethoxy)-8-methyl-8-azabicyclo[3.2.1]octyl 3-N-(3'-nitrophenyl)carbamate. IC50 values for inhibition of cocaine binding and dopamine uptake were 37 and 178 nM, respectively. Amino derivatives were less active than the nitro and (1R-2-exo-3-exo)-2-(carbomethoxy)-8-methyl-8-azabicyclo [3.2.1]octyl 3-N-(4'-aminophenyl)carbamate had the lowest affinity for the receptor with IC50 values of 63 and greater than 100 microM in the aforementioned assays, respectively.

Dermatoglyphics in the identification of women either with or at risk for breast cancer

Fingerprints and palm prints were studied in 78 breast cancer patients, 391 patients at increased risk for developing breast cancer, and 64 control patients for the purpose of finding a pattern that would identify those women with breast cancer or those who are predisposed to its development. A pattern of 6 or more digital whorls was identified more frequently in women with breast cancer than in those without the disease (P less than 0.01). This finding was independent of known risk factors for breast cancer and was present in 28% of the cancer patients. No correlation was noticed between palm prints and breast cancer. The positive predictive value of 6 or more digital whorls was comparable to that of mammography and that of breast biopsy. With increasing age there was an increase in the positive predictive value associated with 6 or more digital whorls. It is concluded that digital dermatoglyphics may have a future role in identifying women either with or at increased risk for breast cancer such that either risk reduction measures or earlier therapy may be instituted.

Circadian variation of heart rate is affected by environment: a study of continuous electrocardiographic monitoring in members of a symphony orchestra

Twenty four hour ambulatory ST segment monitoring was performed on 48 members (43 players and five members of the management/technical team) of the British Broadcasting Corporation (BBC) symphony orchestra without a history of cardiac disease. This period included final rehearsals and live performances (for audience and radio) of music by Richard Strauss and Mozart at the Royal Festival Hall (n = 36) and Rachmaninov and Tchaikovsky at the Barbican Arts Centre (n = 21). During the period of monitoring one person (2%) had transient ST segment changes. Mean heart rates were significantly higher during the live performances than during the rehearsals. Mean heart rates during the live performance of Rachmaninov and Tchaikovsky were significantly higher than during Strauss and Mozart in those (n = 6) who were monitored on both occasions. Mean heart rates in the management and technical team were higher than those of the players. The recognised circadian pattern of heart rate, with a peak in the morning waking hours, was altered similarly during both concert days, with a primary peak occurring in the evening hours and a lesser peak in the morning for both musicians and management/technical staff. This study showed that environmental factors are of primary importance in defining the circadian pattern of heart rate. This has important implications when identifying peak periods of cardiovascular stress and tailoring drug treatment for patients with angina pectoris.

Maximal oxygen uptake in severe aortic regurgitation: a different view of left ventricular function

Respiratory gas exchange was used to assess left ventricular (LV) function in 22 patients with severe aortic regurgitation (19 men and three women, aged 18 and 70 years, mean 49 years). Anaerobic threshold and symptom-limited maximal oxygen consumption (VO2 max) were measured during treadmill exercise, and the results were compared with conventional echocardiographic and radionuclide indices of LV systolic function. The results were considered with respect to the patients' New York Heart Association functional class. Both rest and exercise LV ejection fractions were variable, but the mean results were similar in all classes. The echocardiographic indices of LV cavity dimensions, fractional shortening, radius/thickness ratio, and systolic wall stress also showed a wide range but with similar mean results in each class. In contrast, VO2 max and anaerobic threshold showed a relationship to functional class. VO2 max was 32.4 +/- 3.4 ml/kg/min in age-matched control subjects; in the patients it was 27.9 +/- 4.7 in class I, 24.7 +/- 5.7 in class II, and 14.2 +/- 2 in the combined class III/IV. Results in patients in classes I and II were similar, but both groups were significantly different from control subjects (p less than 0.05) and from patients in class III/IV (p less than 0.01). About half of the patients with moderate LV dysfunction (judged by reduced VO2 max) were asymptomatic, and LV function was impaired in 4 of 10 patients in class I. Thus, unlike conventional indices of LV function, VO2 max appeared capable of distinguishing patients with moderate-to-severe LV dysfunction from those with little or no LV dysfunction. Measurement of respiratory gas exchange appears to be a valid and useful supplementary means of assessing LV function in severe aortic regurgitation. Further long-term evaluation is required.

Therapeutic rationale for the management of silent ischemia

Prognostic data on the importance of silent ischemia is lacking. Preliminary reports suggest that ambulatory electrocardiographic monitoring provides additional information not contained in the exercise test, but it is still unclear whether silent ischemia is a marker of subsequent events or is responsible for their development. Recent investigations also suggest that intermittent episodes of ischemia may cause myocardial necrosis. Drugs that are effective in the treatment of angina are also effective in the treatment of silent ischemia, but their value in terms of long-term morbidity and mortality is unclear. Recently, the circadian distribution of silent ischemia has been reported in 150 patients off therapy, in 33 receiving nifedipine, and in 41 receiving atenolol. Most ischemic episodes off therapy occurred between 7:30 AM and 7:30 PM with a peak in the morning and a lesser peak in the evening. Nifedipine did not alter the circadian pattern of ischemic episodes; atenolol abolished the morning peak, the peak incidence of ischemia then occurring in the evening. This circadian distribution of ischemic episodes and the observed changes with treatment resemble the reported circadian variations of acute myocardial infarction and sudden death. Large multicenter studies are now being performed to determine the effects of treatment on silent ischemia and how this treatment may influence outcome. Until such studies have been completed, it is not possible to clearly define the indication for drug therapy in the management of silent ischemia.

Characteristics of silent and painful ischaemia during ambulatory monitoring in patients with coronary arterial disease

We compared the characteristics of silent and painful ischaemia during ambulatory ST segment monitoring in 288 patients with documented coronary arterial disease and stable angina. During 12,436 hours of monitoring, 890 ischaemic episodes were recorded, of which 652 (73%) were silent. Silent and painful ischaemic episodes were similar in terms of heart rate at onset of ischaemia, increase in heart rate prior to ischaemia, duration of ischaemia, and percentage of episodes not preceded by an increase in heart rate. Change in the mean maximal ST segment was greater during painful ischaemic episodes (P less than 0.01). Silent ischaemia is characteristically painful ischaemia without the pain.

Synthesis of 3-arylecgonine analogues as inhibitors of cocaine binding and dopamine uptake

3-Arylecgonine analogues were synthesized and characterized by 1H and 13C NMR, IR, and MS. The compounds were synthesized as racemates from cycloheptatriene-7-carboxylic acid or enantiomerically from (-)-cocaine. These analogues were tested for their ability to inhibit [3H]cocaine binding to bovine striatal tissue and to inhibit [3H]dopamine uptake into striatal synaptosomes. Methyl (1RS-2-exo-3-exo)-8-methyl-3-phenyl-8-azabicyclo[3.2.1]octane-2-ca rboxylate was the most potent analogue. IC50 values for inhibition of cocaine binding and dopamine uptake were 20 and 100 nM, respectively. The racemates and the 1R isomers were equally potent inhibitors of binding and uptake. Methyl (1RS-2-endo-3-exo)-3-(2,4-dinitrophenyl)-8-methyl-8-azabicyclo[3.2 .1]octane- 2-carboxylate was the least potent. IC50 for inhibition of both binding and uptake was 40 microM.

The haemodynamic response to ST segment changes during coronary arteriography

Contrast media are known to cause electrocardiographic and haemodynamic changes during coronary arteriography. There is a tendency to proceed with repeated coronary arteriography unless patients develop chest pain, bradycardia or hypotension. We have related the changes in the ST segment to changes in left ventricular end-diastolic pressure, measuring pulmonary arterial diastolic pressure with a transducer tipped catheter. Twenty-five patients were studied, 15 patients with coronary arterial disease, 2 with syndrome X, 3 with coronary arterial spasm (and underlying coronary disease) and 5 normal controls. In control patients, no changes in the ST segment or pulmonary arterial diastolic pressure were recorded. Patients with syndrome X developed ST segment depression in the absence of changes in pulmonary arterial diastolic pressure. Those with coronary arterial spasm and underlying coronary disease developed ST segment depression and a rise in pulmonary arterial diastolic pressure following most injections. In coronary arterial disease, both painful and silent ST segment depression was noted with a rise in pulmonary arterial diastolic pressure. In some instances, a summation effect arose with repeated injections. Major disturbances in the ST segment may occur during coronary arteriography and result in elevation of left ventricular filling pressure.

Pathophysiology of angina

The development and pathophysiology of myocardial ischaemia is a dynamic process in which increased myocardial oxygen demand or decreased coronary blood flow are not the sole determinants. Both these factors are inappropriately altered before, during, or after the onset of ischaemia, and a vicious cycle ensues. Drug therapy should be aimed at not only preventing the development of myocardial ischaemia but also at reversing the abnormal hormonal, metabolic, and haemodynamic effects.

Pulmonary artery pressure changes during exercise and daily activities in chronic heart failure

Long-term continuous pulmonary artery pressure monitoring was used to investigate pressure changes during different types of exercise and normal daily activities in patients with chronic heart failure. Nine men (mean age 55 years) with treated chronic heart failure underwent continuous pulmonary artery pressure measurement with use of a micromanometer-tipped catheter with in vivo calibration and frequency-modulated recording. The mean (+/- SD) maximal systolic pulmonary artery pressure (in mm Hg) was 59.4 +/- 26.1 on treadmill exercise, 54.9 +/- 30.6 on bicycle exercise, 52.5 +/- 26.1 walking up and down stairs and 43.5 +/- 23.9 walking on a flat surface. The mean maximal diastolic pressure (in mm Hg) was 27.8 +/- 14.6 on treadmill exercise, 25.5 +/- 14.9 on bicycle exercise, 24.9 +/- 14.8 walking up and down stairs and 20.4 +/- 12.5 walking on a flat surface. The increase in pulmonary artery pressure did not correlate with the severity of the limiting symptoms except during walking on a flat surface. All patients had marked postural changes in pressure, with the systolic pressure difference from lying to standing ranging from 8 to 25 mm Hg and the diastolic pressure difference ranging from 3 to 13 mm Hg. Eating meals caused an increase in pressure in three patients, but less than that when lying flat. There was an increase in pressure during urination in four patients equal to that when walking on a flat surface. None of these activities was associated with symptoms. Neither symptoms nor pulmonary artery pressure during maximal exercise is the same as during daily activities. This may restrict the value of maximal exercise tests in assessing patients with chronic heart failure.

A nuclear magnetic resonance (NMR) method for the determination of the cis/trans isomeric content of chlorprothixene

Proton NMR spectroscopy was applied to the assignment of the isomeric identity of commercially available chlorprothixene. Nuclear Overhauser effect studies confirmed that the clinically useful isomer is the cis (Z) configuration. An NMR method for determining the isomeric content of chlorprothixene was developed based on integration of the ratio of areas of signal strength of the cis-N-methyl in comparison to the trans-N-methyl resonances.