Reproducibility of cardiopulmonary exercise testing in elderly patients with congestive heart failure

Elderly patients with congestive heart failure, including those with preserved systolic function, underwent maximal cardiopulmonary exercise testing. Maximal exercise oxygen consumption, exercise time, heart rate, respiratory exchange ratio, and ventilatory anaerobic threshold showed good reproducibility.

Enhanced skin permeation of sex hormones with novel topical spray vehicles

The feasibility of using some novel topical spray vehicles for enhanced transdermal delivery of the sex hormones, testosterone (Tes), estradiol (E2), progesterone (Prog), and norethindrone acetate (NA) has been investigated. The new penetration enhancers, padimate O (PadO) and octyl salicylate (OSal) were used and compared with laurocapram (AZ) and oleic acid (OA). A finite dose (5 microL/cm2) of each vehicle was applied to either shed snake skin or swine skin in vitro, and the amount penetrated was measured with flow-through diffusion cells. Partitioning into swine skin was determined after an exposure time of 1 min. Rapid partitioning of Tes and PadO into swine skin occurred after 1 min with 70% and 60% of the applied dose, respectively, remaining in the skin after the unabsorbed dose was removed by rinsing with absolute ethanol. The cumulative amount at 24 h (Q24 h) of Tes penetrating across the snake skin was significantly enhanced (p < 0.05) up to 6-fold for OSal, 3-fold for OA and AZ, and 2-fold for PadO compared to control. Using PadO or AZ, the Q24 h ranged from three- to thirteen-fold over control (p < 0.05) for E2, Prog, and NA. Extrapolation of these data to predict what would happen in humans suggests that it should be possible to deliver clinically relevant amounts of sex hormones in this manner with once daily dosing.

Activity Counseling Trial (ACT): rationale, design, and methods. Activity Counseling Trial Research Group

The Activity Counseling Trial (ACT) is a multicenter, randomized controlled trial to evaluate the effectiveness of interventions to promote physical activity in the primary health care setting. ACT has recruited, evaluated, and randomized 874 men and women 35-75 yr of age who are patients of primary care physicians. Participants were assigned to one of three educational interventions that differ in amount of interpersonal contact and resources required: standard care control, staff-assisted intervention, or staff-counseling intervention. The study is designed to provide 90% power in both men and women to detect a 1.1 kcal.kg-1.day-1 difference in total daily energy expenditure between any two treatment groups, and over 90% power to detect a 7% increase in maximal oxygen uptake, the two primary outcomes. Primary analyses will compare study groups on mean outcome measures at 24 months post-randomization, be adjusted for the baseline value of the outcome measure and for multiple comparisons, and be conducted separately for men and women. Secondary outcomes include comparisons between interventions at 24 months of factors related to cardiovascular disease (blood lipids/lipoproteins, blood pressure, body composition, plasma insulin, fibrinogen, dietary intake, smoking, heart rate variability), psychosocial effect, and cost-effectiveness, and at 6 months for primary outcome measures. ACT is the first large-scale behavioral intervention study of physical activity counseling in a clinical setting, includes a generalizable sample of adult men and women and of clinical setting, and examines long-term (24 months) effects. ACT has the potential to make substantial contributions to the understanding of how to promote physical activity in the primary health care setting.

Thymic stromal organization is regulated by the specificity of T cell receptor/major histocompatibility complex interactions

The thymic architecture is normally compartmentalized into a central medulla surrounded by a peripheral cortical region. We investigated how compartmentalization of the thymic stroma is regulated using T cell receptor (TCR)-transgenic mouse models. Our studies show that the signals generated by TCR/peptide/major histocompatibility complex interactions regulate thymic stromal cell compartmentalization. In TCR-transgenic mice, normal stromal cell compartmentalization occurs when the transgenic TCR is expressed on a background that does not result in skewing toward either positive or negative selection. In models representing strong positive selection, the thymic stromal elements do not fully organize into a central medulla. Instead, small medullary foci are dispersed throughout the thymus with some regions residing directly under the capsule. The highest degree of disorganization in medullary epithelial regions is observed in TCR-transgenic mice that exhibit negative selection. Although the medullary foci lack central organization, the expression in these regions of CD80, CD86 and CD40, as well as the clustering of dendritic cells, is similar to that observed in medullae of wild-type mice. Thus, the organization of the medulla appears to occur in two stages: (1) small medullary epithelial regions that are dispersed in fetal thymi expand and associate with antigen-presenting cells, and (2) the expanded medullary foci organize into a central medullary compartment. Our data suggest a model in which this second stage of stromal cell organization is increasingly inhibited as the normal balance of TCR-mediated signals is skewed by higher-avidity interactions between thymocytes and antigen-presenting cells.

Statistical considerations in the use and analysis of single-subject designs

Single-subject designs measure one individual's responses to some experimental manipulation. Statistical methods exist for validly estimating the effect of an intervention on a specific individual by using data from a single-subject design. However, without strong assumptions regarding how an intervention on one individual relates to its effects on others, the results from a single-subject design provide little useful information on the general utility of the intervention. Examination of a single subject cannot verify these assumptions. Correct analysis of data from such designs allows for the possibility of correlation among the observations and the modeling of any changes over time not related to an intervention effect. When data from single-subject designs are collected, the role of assumptions in both the analysis and the generality of conclusions must be frankly acknowledged. Research often develops in stages and the single-subject design can be useful in early stages for hypothesis generation.

Functional outcomes of acute medical illness and hospitalization in older persons

BACKGROUND

Short-stay hospitalization in older patients is frequently associated with a loss of function, which can lead to a need for postdischarge assistance and longer-term institutionalization. Because little is known about this adverse outcome of hospitalization, this study was conducted to (1) determine the discharge and 3-month postdischarge functional outcomes for a large cohort of older persons hospitalized for medical illness, (2) determine the extent to which patients were able to recover to preadmission levels of functioning after hospital discharge, and (3) identify the patient factors associated with an increased risk of developing disability associated with acute illness and hospitalization.

METHODS

A total of 1279 community-dwelling patients, aged 70 years and older, hospitalized for acute medical illness were enrolled in this multicenter, prospective cohort study. Functional measurements obtained at discharge (Activities of Daily Living) and at 3 months after discharge (Activities of Daily Living and Instrumental Activities of Daily Living) were compared with a preadmission baseline level of functioning to document loss and recovery of functioning.

RESULTS

At discharge, 59% of the study population reported no change, 10% improved, and 31% declined in Activities of Daily Living when compared with the preadmission baseline. At the 3-month follow-up, 51% of the original study population, for whom postdischarge data were available (n=1206), were found to have died (11%) or to report new Activities of Daily Living and/or Instrumental Activities of Daily Living disabilities (40%) when compared with the preadmission baseline. Among survivors, 19% reported a new Activities of Daily Living and 40% reported a new Instrumental Activities of Daily Living disability at follow-up. The 3-month outcomes were the result of the loss of function during the index hospitalization, the failure of many patients to recover after discharge, and the development of new postdischarge disabilities. Patients at greatest risk of adverse functional outcomes at follow-up were older, had preadmission Instrumental Activities of Daily Living disabilities and lower mental status scores on admission, and had been rehospitalized.

CONCLUSION

This study documents a high incidence of functional decline after hospitalization for acute medial illness. Although there are several potential explanations for these findings, this study suggests a need to reexamine current inpatient and postdischarge practices that might influence the functioning of older patients.

Soybean isoflavones improve cardiovascular risk factors without affecting the reproductive system of peripubertal rhesus monkeys

Although the beneficial effects of dietary soybean protein compared with animal proteins on plasma lipids, lipoproteins and atherosclerosis have been known for about 50 years, it has been uncertain whether these effects are due to its amino acid concentrations or other components in soybeans. To assess the effect of soybean protein's alcohol-extractable components (including the isoflavonic phytoestrogens genistein and daidzein) on plasma lipid and lipoprotein concentrations and to establish its lack of effect on the reproductive system, we fed 27 peripubertal male and female rhesus monkeys moderately atherogenic diets in which the source of dietary protein was a soy isolate (20% by weight), either containing phytoestrogens (also termed isoflavones) or with the phytoestrogens removed by alcohol extraction. The study was a crossover design with each period lasting for 6 mo. The phytoestrogen-intact soy protein (compared with the alcohol-extracted soy protein) had favorable effects on plasma lipid and lipoprotein concentrations, specifically by significantly reducing LDL+VLDL cholesterol concentrations in both males and females (approximately 30-40% lower), significantly increasing high density lipoprotein cholesterol (HDLC) concentrations for females (approximately 15% higher) and significantly lowering total plasma cholesterol (TPC):HDLC ratios (approximately 20% lower for males and 50% lower for females). The phytoestrogens had no adverse effects on the reproductive systems of either the males or females, as evaluated by reproductive hormone concentrations and organ weights at necropsy. Thus, the isoflavones in soy protein improve cardiovascular disease risk factors without apparent deleterious effects on the reproductive system of peripubertal rhesus monkeys.

Dominant social status and contraceptive hormone treatment inhibit atherogenesis in premenopausal monkeys

The stress of social subordination is associated with exacerbation of coronary artery atherosclerosis in premenopausal cynomolgus monkeys, possibly as a result of the ovarian dysfunction that reliably accompanies subordinate social status. The primary objective of the current study was to determine whether treatment with an oral contraceptive (OC) provides relative protection from development of atherosclerotic plaques, especially among animals made vulnerable to atherosclerosis by social subordination. In the present study, 193 adult female monkeys (Macaca fascicularis) were placed in social groups of 5 or 6 animals each. Half of the animals were then fed an atherogenic diet to which had been added a triphasic OC, while the remainder received only the atherogenic diet. At the end of 26 months, atherosclerosis was measured in an iliac artery biopsy taken from each monkey. The results demonstrated that among untreated animals subordinate individuals developed significantly more atherosclerosis than did their dominant counterparts (P < .01); however, OC treatment inhibited atherosclerosis in subordinate animals (P < .05) and eliminated the difference between dominant and subordinate animals that was observed in the untreated condition. Subordinate social status and OC treatment were both associated with reduced plasma concentrations of HDL cholesterol (P < .01 for both), and subordinate monkeys also had elevations in LDL cholesterol plus VLDL cholesterol (P < .01). Nonetheless, the interaction between social status and OC treatment remained significant even after covariance adjustment for variation in plasma lipids. Taken together, these results suggest that social subordination worsens, whereas OC treatment inhibits, atherosclerosis, and that these effects are independent of concomitant variability in plasma lipids.

Long-term (5-year) changes in HDL cholesterol in cardiac rehabilitation patients. Do sex differences exist?

BACKGROUND

It is unknown whether the benefits of a cardiac rehabilitation program on HDL cholesterol (HDL-C) are equally achieved in men and women. To study this, we compared changes in HDL-C and other lipids in a large group of men and women participating in a cardiac rehabilitation program for up to 5 years.

METHODS AND RESULTS

We compared changes in HDL-C and other fasting lipids in 553 men and 166 women participating in a cardiac rehabilitation program at baseline and then annually for up to 5 years. Patients exercised 3 days a week at 70% to 85% of their maximum heart rate predetermined by a symptom-limited treadmill test. Aerobic capacity was estimated in metabolic equivalents (METs), and percent body fat was determined by skin-fold measurements. Baseline HDL-C, LDL cholesterol (LDL-C), and total cholesterol were significantly higher in women, whereas the ratio of total cholesterol to HDL-C was lower. Although both men and women showed an increase in HDL-C after 1 year (10% and 7%, respectively), only the women's level continued to increase over 5 years (20% versus 5% for men, P = .03). The sex difference in change in HDL-C remained after adjustment for age and smoking. A nonsignificant trend toward a greater change in HDL-C in women existed after adjustment for baseline percent body fat and estimated METs. The change in the ratio of total cholesterol to HDL-C was also more favorable in women, with a 38% decrease over 5 years compared with a 14% decrease in men (P = .01). Total cholesterol decreased by 20% in women and 8% in men (P = .001), whereas LDL-C dropped by 34% in women and 15% in men (P = .0001). There was no sex difference in change in triglycerides.

CONCLUSIONS

Women with heart disease who participate in a cardiac rehabilitation program may achieve greater lipid benefits over longer periods of time than previously demonstrated in men.

Regression of atherosclerosis in female monkeys

The objective of this study was to determine the structural and functional changes that occur in the artery wall in response to plasma lipid lowering and hormone replacement in surgically postmenopausal monkeys with established coronary artery atherosclerosis. Eighty-eight surgically postmenopausal cynomolgus monkeys were fed an atherogenic diet for 24 months and were then allocated into 4 groups: group 1 (n = 20), a baseline necropsy group; group 2 (n = 25), a lipid-lowering diet only; group 3 (n = 22), lipid lowering plus conjugated equine estrogen treatment equivalent to 0.625 mg/d for a woman; and group 4 (n = 21), lipid lowering plus conjugated equine estrogen and medroxyprogesterone acetate treatment (equivalent to 2.5 mg/d for a woman). Treatment was for 30 months. Histomorphometric analysis of perfusion-fixed coronary arteries revealed that plaque size did not change significantly in any of the groups compared with group 1 (P > .20). Plasma lipid lowering permitted coronary artery remodeling to occur (coronary artery and lumen size doubled compared with group 1) (P < .05); however, hormone therapy did not augment remodeling. Quantitative angiographic analysis of coronary artery reactivity revealed that lipid lowering improved dilator responses to acetylcholine by 22 +/- 4% (P = .01) but not to nitroglycerin (P = .23). Hormone replacement did not further affect vascular reactivity to the agonists tested (P > .4), but addition of medroxyprogesterone acetate diminished the beneficial effects of conjugated estrogens on coronary flow reserve (P = .03). In summary, the major arterial sequelae of lipid lowering in female monkeys were artery and lumen enlargement and improved reactivity of large epicardial coronary arteries. Addition of hormone replacement to the dietary modification did not further augment these improvements, except for the dilator capacity of the coronary microcirculation.

Lessons learned from a prospective meta-analysis

OBJECTIVE

To describe the unique aspects of and the lessons learned in planning and conducting a pooled analysis of multiple trials evaluating interventions to reduce functional decline in hospitalized older persons. Specific examples from the Hospital Outcomes Project for the Elderly (HOPE) meta-analysis are discussed.

DESIGN

A prospective meta-analysis (PMA) that compiled and pooled data from concurrently conducted clinical trials testing related but distinct interventions.

SETTING

The Data Coordinating Center for the prospective meta-analysis coordinated the collection and analysis of common outcome data from five university-affiliated hospitals and one community hospital conducting the clinical trials.

PARTICIPANTS

Acutely ill hospitalized elderly participants at least 65 to 75 years old.

INTERVENTIONS

Treatments being evaluated included exercise, physical therapy, a multidisciplinary geriatric care unit, a multidisciplinary in-hospital intervention with post-discharge care, a nursing-based geriatric care program, and a program to improve detection and evaluation of delirious patients.

CONCLUSION

The prospective meta-analysis provides selected advantages over independently conducted clinical trials and retrospective meta-analyses. It does, however, pose special design and operational challenges that must be addressed well before initiation of the individual trials. Specific issues of concern include: maintaining scientific integrity of both the individual trials and the PMA; reaching consensus on PMA goals, what data to collect, how and when to collect them and how to maintain uniformly high quality data across all sites; defining the role of the Data Coordinating Center in a multicenter project that utilizes different trials and protocols; and establishing policies concerning analyses of the pooled data, publication of pooled analyses, and ownership of the pooled database.

Demonstration of an association among dietary cholesterol, central serotonergic activity, and social behavior in monkeys

Epidemiologic studies link plasma cholesterol reduction to increased mortality rates as a result of suicide, violence, and accidents. Deficient central serotonergic activity is similarly associated with violence and suicidal behavior. We investigated the relationship among dietary and plasma cholesterol, social behavior, and the serotonin system as a possible explanation for these findings. Juvenile cynomolgus monkeys (eight female and nine male) were fed a diet high in fat and either high or low in cholesterol. We then evaluated their behavior over an 8-month period. Plasma lipids and cerebrospinal fluid metabolites of serotonin, norepinephrine, and dopamine were assessed on two occasions, at 4 and 5.5 months after the initiation of behavioral observations. Animals that consumed a low-cholesterol diet were more aggressive, less affiliative, and had lower cerebrospinal fluid concentrations of 5-hydroxyindoleacetic acid than did their high-cholesterol counterparts (p < .05 for each). The association among dietary cholesterol, serotonergic activity, and social behavior was consistent with data from other species and experiments and suggested that dietary lipids can influence brain neurochemistry and behavior; this phenomenon could be relevant to our understanding of the increase in suicide and violence-related death observed in cholesterol-lowering trials.

Genetic estimates for plasma lipids and lipoproteins in cynomolgus monkeys under assortative mating

Data obtained from cynomolgus monkeys selected for total plasma cholesterol (TPC) response to dietary cholesterol and nonselected controls were used to estimate heritability of TPC and lipoprotein concentrations. A total of 345 observations were collected on 57 progeny from 18 sires. Heritability estimates obtained by a paternal half-sib analysis and by regression of offspring on mid-parent values were 0.45 +/- 0.24 and 0.69 +/- 0.18 for TPC, 0.63 +/- 0.30 and 0.64 +/- 0.17 for LDLC, and 0.80 +/- 0.36 and 0.59 +/- 0.14 for HDLC, respectively. These results suggest that TPC and lipoprotein concentrations are influenced by additive genetic effects in cynomolgus monkeys, establishing their importance as an animal model for studying the genetics of lipoproteins.

Evaluation of effects of unmodified niacin on fasting and postprandial plasma lipids in normolipidemic men with hypoalphalipoproteinemia

PURPOSE

The aim of this study was to define the effects of unmodified niacin on basal lipids and lipoproteins and on the plasma triglyceride response to a fatty meal--postprandial or alimentary lipemia--in individuals with low levels of high-density lipoprotein cholesterol (HDL-C) and normal fasting cholesterol and triglyceride concentrations (normolipidemic hypoalphalipoproteinemia, isolated low HDL-C).

PATIENTS AND METHODS

Twenty-eight normolipidemic men (total plasma cholesterol concentration [TC] < 230 mg/dL [< 6 mmol/L], plasma triglyceride [Tg] < 250 mg/dL [2.75 mmol/L]) with low plasma concentrations of HDL-C were randomly assigned to increasing doses of crystalline niacin (up to 3,000 mg/d) or no drug for 12 weeks, then crossed over to the alternate regimen. Outcome measures included changes in plasma lipoproteins and alimentary lipemia.

RESULTS

Fifteen participants completed the study. Mean baseline HDL-C +/- SD was 31.7 +/- 6.2 mg/dL (0.82 +/- 0.16 mmol/L). Mean baseline TC, plasma concentration of low-density lipoprotein cholesterol (LDL-C), and Tg were 192 +/- 29.4 mg/dL (4.97 +/- 0.76 mmol/L), 123 +/- 27 mg/dL (3.17 +/- 0.69 mmol/L), and 197 +/- 75 mg/dL (2.17 +/- 0.83 mmol/L), respectively. Unmodified niacin treatment resulted in significant (P < 0.001) reductions of 14% in TC (to 165 mg/dL, 4.26 mmol/L), 40% in Tg (to 119 mg/dL, 1.31 mmol/L), and 18% in LDL-C (to 101 mg/dL, 2.60 mmol/L) and significant increases of 30% in HDL-C (to 42 mg/dL, 1.07 mmol/L), 100% in HDL2 cholesterol (from 5 mg/dL to 9 mg/dL, 0.12 mmol/L to 0.24 mmol/L), and 21% in HDL3 cholesterol (from 27 mg/dL to 33 mg/dL, 0.70 mmol/L to 0.85 mmol/L). Unmodified niacin treatment reduced alimentary lipemia by 45% (P < 0.02).

CONCLUSIONS

Crystalline niacin effectively raises HDL-C, lowers LDL-C, and reduces alimentary lipemia in patients with isolated low HDL-C. However, many patients have difficulty tolerating the drug, and supervision may be required to sustain patient compliance and avoid toxicity.

Clinical application of polymerase chain reaction amplification to diagnosis of herpes virus infection

Amplification of viral DNA offers a potentially sensitive and specific method for identifying herpes viruses in pathologic specimens. The purpose of this study is to assess the value of polymerase chain reaction amplification of DNA as a diagnostic test for herpes virus in pathologic specimens. The purpose of this study is to assess for herpes virus infections. We examined 79 paraffin-embedded tissue samples from 43 patients and 55 viral culture samples from 45 patients. Herpes virus DNA in the specimens was amplified by polymerase chain reaction. Using paraffin-embedded tissue on which a diagnosis of herpes virus was made by morphologic criteria, 11 of 19 patients had herpes virus DNA identified by PCR; herpes virus DNA was not identified in any of 35 negative control specimens. Herpes virus DNA was also identified by polymerase chain reaction in all of the positive herpes virus culture specimens. Of 29 culture negative specimens, herpes virus DNA was identified in six. We conclude that polymerase chain reaction is useful to establish or confirm the presence of a herpes virus infection in paraffin-embedded tissue samples and that it is more sensitive than viral culture.

Terminal ballistics of the 9mm with Action Safety bullet or Blitz-Action-Trauma (BAT) ammunition

Specialty ammunition creating atypical gunshot wounds of entrance can create confusion and may be misinterpreted by pathologists unfamiliar with the terminal ballistics of these projectiles. The previously unreported wound ballistics caused by the 9mm with Action Safety bullet described in a homicide highlights the atypical entrance wound(s) and wounding capacity of this novel ammunition. Manufactured by Geco division of Dynamit Nobel, the bullet consists of a nonjacketed solid copper alloy bullet body without a conventional lead core. The large deformation well and part of the smaller central channel is filled with a hard plastic core and post that creates a round nose bullet. The internal ballistics and unique design allow the plastic nose cap and post to separate from the copper alloy base while still in the barrel. The radiolucent nose cap leaves the bullet's path but can still penetrate tissue giving the appearance of a separate but smaller entrance wound. The sharp leading edge of the deformation well and relative high velocity of the bullet body creates a punched out entrance wound with minimal marginal abrasion. When the plastic nose cap or fragments of the plastic post impact the subject, test firings may allow an inference to the muzzle-target distance even in the absence of soot deposition or stippling.

Dietary polyunsaturated fat decreases coronary artery atherosclerosis in a pediatric-aged population of African green monkeys

The hypothesis tested was that juvenile African green monkeys consuming diets enriched with n-6 polyunsaturated fat from birth until young adulthood would have significantly less coronary artery atherosclerosis than comparable animals consuming diets enriched with saturated fat. African green monkeys (Cercopithecus aethiops, n = 108) of both sexes were fed atherogenic diets (0.8 mg cholesterol/kcal) throughout their lives so that death at 16, 32, or 60 months of age permitted quantification of atherosclerosis. In the coronary arteries, the average intimal area increased significantly with age (P = .02), showing increases of 28-fold and sevenfold between 32 and 60 months in the saturated fat- and polyunsaturated fat-fed groups, respectively. Young adult male animals at 60 months of age were found to have significantly (P = .03) more coronary artery atherosclerosis than female animals. Animals fed polyunsaturated fat had significantly (P < or = .01) less coronary artery atherosclerosis. By 60 months of age in the animals consuming polyunsaturated fat, the average coronary artery intimal area was one fourth and the average size of the largest coronary intimal lesion was one fifth that in monkeys fed saturated fat. Low-density lipoprotein (LDL) cholesterol and LDL particle size were each found to be positively correlated with coronary artery atherosclerosis end points in both diet groups. In addition to the coronary arteries, atherosclerosis in the abdominal and thoracic aorta and carotid arteries was also evaluated; the coronary arteries were the only arterial system with significantly less atherosclerosis in the polyunsaturated fat group as measured by intimal area. However, evaluation of histological sections of abdominal aorta showed relatively more sterol clefts in the saturated fat-fed group, and more free cholesterol was measured, suggesting that lesions were more complicated in this group. These results show that dietary intervention early in life with n-6 polyunsaturated fat can be effective in decreasing the development of atherosclerosis, particularly in the coronary arteries of primates. This outcome supports the concept that dietary intervention beginning early in childhood can have beneficial effects on the coronary heart disease of later life.

Remodeling of coronary arteries in human and nonhuman primates

OBJECTIVE

To compare coronary artery remodeling (compensatory enlargement) in human and nonhuman primates.

DESIGN

Coronary artery data were analyzed retrospectively for 416 nonhuman primates and 100 men and women.

SETTING

The monkeys had been in experiments involving diet-induced coronary artery atherosclerosis. The human hearts were obtained from the North Carolina Baptist Hospital, Winston-Salem, and age greater than 25 years was the only criterion.

PATIENTS AND OTHER PARTICIPANTS

The left anterior descending coronary arteries from 100 humans, 328 cynomolgus monkeys, and 88 male rhesus monkeys were used.

INTERVENTIONS

None; this was a cross-sectional observational study.

MAIN OUTCOME MEASURES

Coronary artery size, lumen area, and plaque size. In the humans, we also examined demographic characteristics (ethnicity, sex, and history of hypertension) and pathologic criteria (eccentricity or concentricity of plaque area).

RESULTS

On average, lumen size remained unaffected by plaque size. Lumen size was variable and could not be predicted by traditional risk factors for coronary heart disease. However, lack of compensation (decreased lumen size as plaques enlarged) and history of coronary heart disease were significantly correlated.

CONCLUSIONS

The similarity of remodeling in human and nonhuman primates suggests that the process has general biologic significance. Lack of remodelling may be a major determinant of whether a person with coronary artery atherosclerosis develops its complications.

Potent nonpeptide angiotensin II receptor antagonists. 2. 1-(Carboxybenzyl)imidazole-5-acrylic acids

The further evolution of the imidazole-5-acrylic acid series of nonpeptide angiotensin II receptor antagonists is detailed (for Part 1, see: J. Med. Chem. 1992, 35, 3858). Modifications of the N-benzyl ring substitution were undertaken in an effort to mimic the Tyr4 residue of angiotensin II. Introduction of a p-carboxylic acid on the N-benzyl ring resulted in the discovery of compounds with nanomolar affinity for the receptor and good oral activity. SAR studies of these potent antagonists revealed that the thienyl ring, the (E)-acrylic acid, and the imidazole ring in addition to the two acid groups were important for high potency. Also, overlay comparisons of the parent diacid with both angiotensin II and a representative biphenylyltetrazole nonpeptide angiotensin II receptor antagonist are presented. The parent diacid analog, SK&F 108566 or (E)-3-[2-butyl-1-(4-carboxybenzyl)-1H-imidazole-5-yl]-2-[(2- thienyl)methyl]propenoic acid, is currently in clinical development for the treatment of hypertension.

Childhood consumption of dietary polyunsaturated fat lowers risk for coronary artery atherosclerosis in African green monkeys

This study was designed to test the hypothesis that consumption of diets enriched in polyunsaturated fatty acids beginning at birth and continuing into young adulthood would lower the risk for atherosclerotic coronary heart disease early in life through their effects on plasma lipid and apolipoprotein concentrations while supporting good health and normal development. Accordingly, African green monkeys (n = 140) were raised on atherogenic diets (0.8 mg cholesterol per kcal) enriched with either saturated or n-6 polyunsaturated fatty acids. Breast milk from mothers fed the polyunsaturated fat diet became enriched in polyunsaturated fatty acids relative to the saturated group; thus, the period of nursing also reflected the dietary fatty acid shift. Age, gender, and dietary fat type independently affected plasma lipid and apolipoprotein concentrations. Age effects were similar for all lipid and lipoprotein variables; the concentrations were low immediately after birth, increased dramatically during the first 4-6 months of life, and then attained levels similar to those of adult animals by 2 years of age. Significant differences by gender were found such that females maintained lower total plasma cholesterol concentrations and higher high density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-I concentrations. Dietary fat effects were age dependent. Before weaning at 5 months of age, total plasma cholesterol and apoB concentrations were lower in animals consuming polyunsaturated fat, and this pattern was maintained into young adulthood. Lower concentrations of plasma triglycerides, HDL cholesterol, and apoA-I for polyunsaturated fat-fed animals were found only in the postweaning period (6-60 months of age). Since this pattern of response to dietary polyunsaturated fat in the juvenile animals was similar to that for adult animals fed these same diets in which there was less atherosclerosis and because subsequent studies have documented less coronary artery atherosclerosis in the polyunsaturated fat-fed juveniles, we conclude that early dietary intervention was beneficial in this group for lowering the risk of coronary artery atherosclerosis. The results in this primate model support the concept that intervention to modify coronary heart disease risk that is initiated early in childhood will have beneficial effects.

Imidazole-5-acrylic acids: potent nonpeptide angiotensin II receptor antagonists designed using a novel peptide pharmacophore model

A series of novel nonpeptide angiotensin II receptor antagonists containing a substituted (E)-acrylic acid has been developed. The overlay of 1, an imidazole-5-acetic acid found in the patent literature, on a novel pharmacophore model of AII suggested that extension of the acid side chain and attachment of a second aryl residue to mimic the C-terminal phenylalanine region of AII would lead to increased activity. A study of extended acid side chains at C-5 of the imidazole nucleus led to the discovery of the (E)-acrylic acid 5 as a promising starting point for further exploration. As predicted by the modeling, substitution of a benzyl group on the acrylic acid side chain to mimic the phenylalanine gave increased potency. An extensive study of the SAR of the newly introduced aromatic ring revealed that electron-rich heteroaryl rings provided improved activity, most notably in the in vivo rat models. Compound 40, (E)-3-[2-butyl-1- [(2-chlorophenyl)methyl]imidazol-5-yl]-2-[(2-thienyl)methyl]-2- propenoic acid, has been shown to be a potent, competitive, and orally active small molecule AT-1 receptor antagonist. It exhibits a 2 orders of magnitude increase in binding affinity and a 10-fold improvement in in vivo potency as compared to compound 1 and represents an important milestone in the development of even more potent nonpeptide angiotensin II receptor antagonists.