Relation of cardiac prognosis to segment location with apical left ventricular ischemia

Previously, we have shown that myocardial ischemia induced during intravenous dobutamine in the distal segments composing the left ventricular apex is associated with a heightened risk of future myocardial infarction or cardiac death. In this study, we find this heightened risk is present independent of the location of the distal segment within the left ventricular apex.

A randomized, controlled trial comparing two different continuous positive airway pressure systems for the successful extubation of extremely low birth weight infants

OBJECTIVE

To determine whether the use of the Infant Flow continuous positive airway pressure (IF CPAP) system reduces the rate of extubation failure among extremely low birth weight (ELBW) infants (infants with birth weight <1000 g) when compared with conventional CPAP delivered with a conventional ventilator and nasal prongs.

METHODS

A prospective, unmasked, randomized, controlled clinical trial was conducted in 162 eligible intubated ELBW infants who were hospitalized in 2 intensive care nurseries in Winston-Salem, North Carolina, between July 1997 and November 2000. Successful extubation was defined as no need for reintubation for any reason for at least 7 days after the first extubation attempt.

RESULTS

The individual extubation success rates were 61.9% (52 of 84) in the conventional CPAP group and 61.5% (48 of 78) in the IF CPAP group. There were no significant differences in the extubation success rate in any birth weight subset between the 2 cohorts. The most common cause of extubation failure was apnea/bradycardia. Infants who were randomized to IF CPAP had fewer days on supplemental O(2) and shorter hospital stays.

CONCLUSIONS

Extubation failure is a common problem, occurring in nearly 40% of ELBW infants who require mechanical ventilation. IF CPAP was as effective but no more effective than conventional CPAP in preventing extubation failure among ELBW infants. New strategies are needed to identify predictors of extubation success and to treat apnea/bradycardia, the most common cause of extubation failure, thereby reducing the likelihood of prolonged intubation in this high-risk cohort of premature infants.

Exercise responses of elderly patients with diastolic versus systolic heart failure

PURPOSE

Little information is available regarding peak and submaximal exercise performance in elderly heart failure (HF) patients, particularly in those with diastolic dysfunction (DD). Therefore, the purpose of this investigation was to compare exercise responses of elderly patients with HF due to either systolic dysfunction (SD) or DD, to age-matched healthy volunteers (HV).

METHODS

Patients with chronic HF > or = 60 yr (N = 119) due to SD (N = 60) or primary DD (N = 59) underwent a maximal cycle ergometry test with expired gas analysis and venous lactate measurement. Twenty-eight HV > or = 60 yr served as a control group. Anaerobic threshold was determined by gas analysis (ATVEN) and by plasma lactate rise (ATLAC).

RESULTS

Peak oxygen consumption (VO(2peak)) was significantly (P < 0.001) reduced in both SD and DD patients (13 +/- 0.4 vs 14 +/- 0.4 ml x kg(-1) x min(-1), respectively) versus HV (20 +/- 0.6 ml x kg(-1) x min(-1)). Peak heart rate was reduced in patients versus HV (131 +/- 3 bpm vs 145 +/- 4, respectively; P < or = 0.01), but heart rate at a given submaximal work rate was significantly lower (P < or = 0.01) in HV than in SD and DD patients. ATVEN of 11.8 +/- 0.3 ml x kg(-1) x min(-1) for HV was significantly higher than SD (8.9 +/- 0.2) and DD (9.2 +/- 0.3). Peak lactate concentration was 6.6 +/- 0.6 mmol x kg(-1) x l(-1) in HV and was significantly reduced in both SD and DD HF patients. ATVEN correlated well with ATLAC in HV and in DD patients, but not in SD patients.

CONCLUSIONS

Submaximal and peak exercise performance are markedly altered in elderly HF patients compared with age-matched HV but do not appear to be different between SD and DD patients.

Overestimation of genetic risks owing to small sample sizes in cardiovascular studies

We sought evidence of publication bias to explain conflicting findings in studies of angiotensin-converting enzyme deletion polymorphism (ACE D) and glycoprotein IIIa PlA2 (PLA2) polymorphism and the risk of myocardial infarction. Factor 5 Leiden (F5L), a well-established thrombotic risk factor, served as an internal comparison. We conducted systematic reviews of published studies involving ACE D, PLA2, F5L and relevant outcomes, searching medline (January 1990 through February, 2001), bibliographies, and meta-analyses. Random effects pooled odds ratios (95% confidence interval) for cardiovascular outcomes were as follows: PLA2 (n = 13,167 subjects): 1.13 (1.02, 1.26); ACE D (n = 42,140 subjects): 1.22 (1.11, 1.35); and F5L (n = 27,277 subjects): 4.43 (3.65, 5.38). However, funnel plots of ACE D and PLA2, but not F5L, showed an inverse relationship between sample size and odds ratios for ACE D (p = 0.02) and PLA2 (p = 0.04) but not F5L (p = 0.65) by Egger's test for potential publication bias. Despite research-based genotyping of over 50,000 subjects, the overall risk for myocardial infarction as a result of PLA2 and ACE D remains doubtful. Our study provides a clear example of how publication of underpowered studies can spuriously implicate polymorphisms as genetic risk factors.

Design of Phase II cancer trials evaluating survival probabilities

BACKGROUND

Phase II cancer studies are undertaken to assess the activity of a new drug or a new treatment regimen. Activity is sometimes defined in terms of a survival probability, a binary outcome such as one-year survival that is derived from a time-to-event variable. Phase II studies are usually designed with an interim analysis so they can be stopped if early results are disappointing. Most designs that allow for an interim look are not appropriate for monitoring survival probabilities since many patients will not have enough follow-up by the time of the interim analysis, thus necessitating an inconvenient suspension of accrual while patients are being followed.

METHODS

Two-stage phase II clinical trial designs are developed for evaluating survival probabilities. These designs are compared to fixed sample designs and to existing designs developed to monitor binomial probabilities to illustrate the expected reduction in sample size or study length possible with the use of the proposed designs.

RESULTS

Savings can be realized in both the duration of accrual and the total study length, with the expected savings increasing as the accrual rate decreases. Misspecifying the underlying survival distribution and the accrual rate during the planning phase can adversely influence the operating characteristics of the designs.

CONCLUSION

Two-stage phase II trials for assessing survival probabilities can be designed that do not require prolonged suspension of patient accrual. These designs are more efficient than single stage designs and more practical than existing two-stage designs developed for binomial outcomes, particularly in trials with slow accrual.

Soy protein and isoflavone effects on vasomotor symptoms in peri- and postmenopausal women: the Soy Estrogen Alternative Study

OBJECTIVE

To investigate the efficacy of dietary soy proteins containing differing amounts of isoflavones on the number and severity of vasomotor symptoms (hot flashes and night sweats) in peri- and postmenopausal women.

DESIGN

A double-masked, randomized, controlled, clinical trial was conducted. A total of 241 community-dwelling women reporting vasomotor symptoms at baseline were randomized into one of three groups. In all groups, participants consumed a daily supplement containing 25 g of soy protein and were randomly assigned to one of three groups: (a) isoflavone extracted soy protein (control), (b) soy protein with a medium dose of isoflavones (42 mg/day), or (c) soy protein with a higher dose of isoflavones (58 mg/day). The primary outcome measure in this trial was change in reported vasomotor symptoms.

RESULTS

A reduction in the number and severity of vasomotor symptoms was observed in all three treatment groups. No significant differences in the number and severity of vasomotor symptoms were observed among the high isoflavone, middle isoflavone, or control groups. The lack of a between-treatment group effect was observed even after stratified by number of baseline symptoms and use of traditional hormone replacement therapy.

CONCLUSIONS

These data suggest that soy protein containing 42 or 58 mg of isoflavones is no more effective than isoflavone-extracted soy protein for improving the number and severity of vasomotor symptoms in peri- and postmenopausal women.

Relation of aortic distensibility determined by magnetic resonance imaging in patients > or =60 years of age to systolic heart failure and exercise capacity

Aortic stiffness increases with advancing age and is associated with the age-related decline in exercise capacity in healthy persons. Previous studies have suggested that aortic compliance is reduced in heart failure (HF). Older persons with systolic HF can have particularly severe exercise intolerance. However, the relation between increased aortic stiffness and exercise intolerance in elderly patients with systolic HF has not been examined. Therefore, aortic distensibility of the proximal ascending aorta (assessed by magnetic resonance imaging) and exercise tolerance (assessed by maximal exercise ergometry with expired gas analysis) was measured in 28 subjects (10 healthy subjects aged 20 to 30 years, 10 healthy subjects aged > or =60 years, and 8 subjects aged > or =60 years with systolic HF). Compared with healthy older subjects, patients with systolic HF had markedly decreased distensibility of the proximal aorta (0.5 +/- 0.4 vs 2.2 +/- 1.2 10(-3) mm Hg(-1), p <0.002), decreased peak exercise volume of oxygen consumption (VO2) (858 +/- 248 vs 1,436 +/- 344 ml/min, p <0.001), and increased aortic wall thickness (3.6 +/- 0.7 vs 2.9 +/- 0.4 mm, p <0.04). Aortic distensibility was significantly correlated with peak VO2 (r = 0.80, p <0.0001) and remained so even after being adjusted for age and left ventricular (LV) ejection fraction. These data suggest that decreased aortic distensibility may contribute to exercise intolerance in older patients with HF due to LV systolic dysfunction.

Pathophysiological characterization of isolated diastolic heart failure in comparison to systolic heart failure

CONTEXT

Many older patients with symptoms of congestive heart failure have a preserved left ventricular ejection fraction (LVEF). However, the pathophysiology of this disorder, presumptively termed diastolic heart failure (DHF), is not well characterized and it is unknown whether it represents true heart failure.

OBJECTIVE

To assess the 4 key pathophysiological domains that characterize classic heart failure by systematically performing measurements in older patients with presumed DHF and comparing these results with those from age-matched healthy volunteers and patients with classic systolic heart failure (SHF).

DESIGN AND SETTING

Observational clinical investigation conducted in 1998 in a general community and teaching hospital in Winston-Salem, NC.

PARTICIPANTS

A total of 147 subjects aged at least 60 years. Fifty-nine had isolated DHF defined as clinically presumed heart failure, LVEF of at least 50%, and no evidence of significant coronary, valvular, or pulmonary disease. Sixty had typical SHF (LVEF < or =35%). Twenty-eight were age-matched healthy volunteer controls.

MAIN OUTCOME MEASURES

Left ventricular structure and function, exercise capacity, neuroendocrine function, and quality of life.

RESULTS

By echocardiography, mean (SE) LVEF was 60% (2%) in patients with DHF vs 31% (2%) in those with SHF and 54% (2%) in controls. Mean (SE) LV mass-volume ratio was markedly increased in patients with DHF (2.12 [0.14] g/mL) vs those with SHF (1.22 [0.14] g/mL) (P<.001) and vs controls (1.49 [0.17] g/mL) (P =.002). Peak oxygen consumption by expired gas analysis during cycle ergometry was similar in the DHF and SHF groups (14.2 [0.5] and 13.1 [0.5] mL/kg per minute, respectively; P =.40) and in both was markedly reduced compared with healthy controls (19.9 [0.7] mL/kg per minute) (P =.001 for both). Ventilatory anaerobic threshold was similar in the DHF and SHF groups (9.1 [0.3] and 8.7 [0.3] mL/kg per minute, respectively; P<.001) and in both was reduced compared with healthy controls (11.5 [0.4] mL/kg per minute) (P<.001). Norepinephrine levels were similar in the DHF (306 [64] pg/mL) and SHF (287 [62] pg/mL) groups (P =.56) and in both were markedly increased vs healthy controls (169 [80] pg/mL) (P =.007 and.03, respectively). Brain natriuretic peptide was substantially increased in both the DHF (56 [30] pg/mL) and the SHF (154 [28] pg/mL) groups compared with healthy controls (3 [38] pg/mL) (P =.02 and.001, respectively). Quality-of-life decrement score as assessed by the Minnesota Living with Heart Failure Questionnaire was substantially increased from the benchmark score of 10 in both groups (SHF: 43.8 [3.9]; DHF: 24.8 [4.4]).

CONCLUSION

Patients with isolated DHF have similar though not as severe pathophysiologic characteristics compared with patients with typical SHF, including severely reduced exercise capacity, neuroendocrine activation, and impaired quality of life.

Magnetic resonance imaging determination of cardiac prognosis

BACKGROUND

Regional assessments of left ventricular (LV) wall motion obtained during MRI cardiac stress tests can be used to identify myocardial injury and ischemia, but the utility of MRI stress test results for the assessment of cardiac prognosis is not known.

METHODS AND RESULTS

Two hundred seventy-nine patients referred (because of poor LV endocardial visualization with echocardiography) for dobutamine/atropine MRI for the detection of inducible ischemia were followed for an average of 20 months. After MRI stress testing, the occurrence of myocardial infarction, cardiac death, death attributable to any cause, coronary arterial revascularization, and unstable angina or congestive heart failure requiring hospitalization was determined. In a multivariate analysis, the presence of inducible ischemia (hazard ratio 3.3, CI 1.1 to 9.7) or an LV ejection fraction <40% (hazard ratio 4.2, CI 1.3 to 13.9) was associated with future MI or cardiac death independent of the presence of risk factors for coronary arteriosclerosis.

CONCLUSIONS

In patients with poor echocardiograms, the results of cardiac MRI stress tests can be used to forecast myocardial infarction or cardiac death.

Brachial flow-mediated vasodilator responses in population-based research: methods, reproducibility and effects of age, gender and baseline diameter

BACKGROUND

Brachial artery ultrasound has been proposed as an inexpensive, accurate way to assess cardiovascular risk in populations. However, analysis and interpretation of these data are not uniform.

METHODS

We analysed the relationship between relative and absolute changes in brachial artery diameter in response to flow-mediated dilation and age, gender and baseline diameter among 4,040 ultrasound examinations from subjects aged 14 to 98 years.

RESULTS

Reproducibility studies demonstrated intra- and interreader and intrasubject correlations from 0.67 to 0.84 for repeated measures of per cent change in diameter. Per cent change in diameter after flow stimulus was 3.58 +/- 0.10% (mean +/- standard deviation). Corresponding values for baseline diameter and absolute change in diameter were 4.43 +/- 0.87 mm and 0.15 +/- 0.01 mm, respectively. Baseline diameter and its variance were inversely related to per cent change in diameter (P< 0.001). In contrast, absolute change in diameter was more uniform throughout the range of baseline diameters. Baseline diameter was directly related, and per cent change in diameter inversely related, to age (P < 0.001 for all three measures). Time to maximum vasodilator response increased with age (P < 0.001). Women (n=2,315) had significantly larger per cent change in diameter than men (n=1,725) (P < 0.001). However, after adjustment for age and baseline diameter, per cent and absolute change were 5% smaller in women than men (P < 0.05 for both). In multivariate analysis, age was overwhelmingly the most important determinant of absolute change in diameter (P < 0.001).

CONCLUSIONS

Automated analysis of brachial flow-mediated vasodilator responses is both feasible and reproducible in large-scale clinical and population-based research.

Cardiac cycle-dependent changes in aortic area and distensibility are reduced in older patients with isolated diastolic heart failure and correlate with exercise intolerance

OBJECTIVES

The goal of this study was to determine if cardiac cycle-dependent changes in proximal thoracic aortic area and distensibility are associated with exercise intolerance in elderly patients with diastolic heart failure (DHF).

BACKGROUND

Aortic compliance declines substantially with age. We hypothesized that a reduction in cardiac cycle-dependent changes in thoracic aortic area and distensibility (above that which occurs with aging) could be associated with the exercise intolerance that is prominent in elderly diastolic heart failure patients.

METHODS

Thirty subjects (20 healthy individuals [10 < 30 years of age and 10 > 60 years of age] and 10 individuals > the age of 60 years with DHF) underwent a magnetic resonance imaging (MRI) study of the heart and proximal thoracic aorta followed within 48 h by maximal exercise ergometry with expired gas analysis.

RESULTS

The patients with DHF had higher resting brachial pulse and systolic blood pressure, left ventricular mass, aortic wall thickness and mean aortic flow velocity, and, compared with healthy older subjects, they had a significant reduction in MRI-assessed cardiac cycle-dependent change in aortic area and distensibility (p < 0.0001) that correlated with diminished peak exercise oxygen consumption (r = 0.79). After controlling for age and gender in a multivariate analysis, thoracic aortic distensibility was a significant predictor of peak exercise oxygen consumption (p < 0.04).

CONCLUSIONS

Older patients with isolated DHF have reduced cardiac cycle-dependent changes in proximal thoracic aortic area and distensibility (beyond that which occurs with normal aging), and this correlates with and may contribute to their severe exercise intolerance.

The economic impact of wasted prescription medication in an outpatient population of older adults

The causes and costs of outpatient medication waste are not known. We report the results of a cross-sectional pilot survey of medication waste in a convenience sample of 73 New Hampshire retirement community residents aged 65 years or older. We used questionnaires and in-home pill counts to determine the annual occurrence of medication waste, defined as no intention to take leftover medicines prescribed within the past year. Mean individual annual cost of wasted medication was $30.47 (range = $0-$131.56). Waste represented 2.3% of total medication costs. The main causes for waste included: resolution of the condition for which the medication was prescribed (37.4%), patient-perceived ineffectiveness (22.6%), prescription change by the physician (15.8%), and patient-perceived adverse effects (14.4%). Individual costs were modest, but if $30 per person represents a low estimate of average annual waste, the US national cost for adults older than 65 years would top $1 billion per year.

Group comparisons involving missing data in clinical trials: a comparison of estimates and power (size) for some simple approaches

When using 'intent-to-treat' approaches to compare outcomes between groups in clinical trials, analysts face a decision regarding how to account for missing observations. Most model-based approaches can be summarized as a process whereby the analyst makes assumptions about the distribution of the missing data in an attempt to obtain unbiased estimates that are based on functions of the observed data. Although pointed out by Rubin as often leading to biased estimates of variances, an alternative approach that continues to appear in the applied literature is to use fixed-value imputation of means for missing observations. The purpose of this paper is to provide illustrations of how several fixed-value mean imputation schemes can be formulated in terms of general linear models that characterize the means of distributions of missing observations in terms of the means of the distributions of observed data. We show that several fixed-value imputation strategies will result in estimated intervention effects that correspond to maximum likelihood estimates obtained under analogous assumptions. If the missing data process has been correctly characterized, hypothesis tests based on variances estimated using maximum likelihood techniques asymptotically have the correct size. In contrast, hypothesis tests performed using the uncorrected variance, obtained by applying standard complete data formula to singly imputed data, can provide either conservative or anticonservative results. Surprisingly, under several non-ignorable non-response scenarios, maximum likelihood based analyses can yield equivalent hypothesis tests to those obtained when analysing only the observed data.

Duration of accrual and follow-up for two-stage clinical trials

Group sequential trials with time to event end points can be complicated to design. Not only are there unlimited choices for the number of events required at each stage, but for each of these choices, there are unlimited combinations of accrual and follow-up at each stage that provide the required events. Methods are presented for determining optimal combinations of accrual and follow-up for two-stage clinical trials with time to event end points. Optimization is based on minimizing the expected total study length as a function of the expected accrual duration or sample size while providing an appropriate overall size and power. Optimal values of expected accrual duration and minimum expected total study length are given assuming an exponential proportional hazards model comparing two treatment groups. The expected total study length can be substantially decreased by including a follow-up period during which accrual is suspended. Conditions that warrant an interim follow-up period are considered, and the gain in efficiency achieved by including an interim follow-up period is quantified. The gain in efficiency should be weighed against the practical difficulties in implementing such designs. An example is given to illustrate the use of these techniques in designing a clinical trial to compare two chemotherapy regimens for lung cancer. Practical considerations of including an interim follow-up period are discussed.

Inhibition of postmenopausal atherosclerosis progression: a comparison of the effects of conjugated equine estrogens and soy phytoestrogens

Experimental evidence was sought concerning whether soy phytoestrogens (SPEs) inhibit postmenopausal atherosclerosis progression/extent and, if so, their effectiveness relative to traditional estrogen replacement therapy. Premenopausal cynomolgus monkeys were fed a moderately atherogenic diet (26 months) to induce atherosclerosis. After ovariectomy, the moderately atherogenic diet was continued, and they were treated (36 months) with a control diet (soy protein depleted of SPEs), a diet containing SPEs in soy protein isolate, or a diet containing SPE-depleted soy protein with conjugated equine estrogens (CEE; Premarin) added. SPE effects on plasma lipids were better than those of CEE (higher high density lipoprotein cholesterol and no increase in triglyceride). Relative to the control group, CEE treatment inhibited (P = 0.0001), and SPE treatment partially inhibited (P = 0.10) the progression of atherosclerosis (common iliac artery atherosclerosis before and after treatment). CEE-treated monkeys had much less coronary artery atherosclerosis than the controls (P = 0.0002), whereas SPE-treated monkeys were intermediate in lesion extent between the controls and the CEE-treated animals (P = 0.02). Both CEE and SPE significantly reduced the extent of common carotid and internal carotid artery atherosclerosis, and the two treatment groups were not significantly different.

The effects of prolonged administration of 5-bromodeoxyuridine on cells of the immune system

We have determined the in vivo effect of 5-bromodeoxyuridine (BrdU) administered to mice in the drinking water for various lengths of time on the performance of T and B lymphocytes in a number of experimental protocols. Young mice continuously exposed to BrdU fail to gain weight, and the lymphocytes recovered after a prolonged period of exposure are fewer in number than in control mice. The recovery of normal levels of T and B lymphocytes after irradiation is severely impaired. Ag-specific cells responding to Ag in an adoptive transfer model fail to expand as much in the presence of BrdU as in the absence, and the Ag-specific effectors produced in the presence of BrdU are less able to secrete cytokines upon restimulation in vitro. Polarized populations of Tc1 and Tc2 effectors generated in vitro proliferate less in the presence of BrdU, and the resulting effectors make less cytokines per cell upon restimulation. Thus, the incorporation of BrdU into T or B lymphocytes can, under some circumstances, seriously impair the performance of the labeled cells, and these findings raise a note of caution in the interpretation of studies that make use of long-term exposure to BrdU.

In vitro oxidation of low-density lipoprotein in two species of nonhuman primates subjected to caloric restriction

Caloric restriction (CR), which increases longevity and retards age-associated diseases in laboratory rodents, is being evaluated in nonhuman primate trials. CR reduces oxidative stress in rodents and appears to improve risk factors for cardiovascular disease in nonhuman primates. We tested the hypothesis that low-density lipoprotein (LDL) oxidizability is reduced in two monkey species (rhesus and cynomolgus) subjected to chronic CR. In both species, no significant differences occurred between CR and control animals on total, LDL, or high-density lipoprotein (HDL) cholesterol. In rhesus monkeys, triglycerides were higher in controls than CR (139 +/- 23 vs 66 +/- 8 mg/dl,p < .01, respectively). LDL from CR rhesus monkeys was reduced in triglyceride content and molecular weight compared to controls, whereas LDL composition in cynomolgus monkeys was similar in CR and control animals. In keeping with minor deviations in lipids, antioxidants, and LDL composition, no consistent differences in in vitro LDL oxidizability were apparent between CR and controls in either species.

Naive, effector, and memory CD8 T cells in protection against pulmonary influenza virus infection: homing properties rather than initial frequencies are crucial

The goal of adoptive immunotherapy is to target a high number of persisting effector cells to the site of a virus infection or tumor. In this study, we compared the protective value of hemagglutinin peptide-specific CD8 T cells generated from the clone-4 TCR-transgenic mice, defined by different stages of their differentiation, against lethal pulmonary influenza infection. We show that the adoptive transfer of high numbers of Ag-specific unprimed, naive CD8 T cells failed to clear the pulmonary virus titer and to promote host survival. The same numbers of in vitro generated primary Ag-specific Tc1 effector cells, producing high amounts of IFN-gamma, or resting Tc1 memory cells, generated from these effectors, were protective. Highly activated CD62Llow Tc1 effectors accumulated in the lung with rapid kinetics and most efficiently reduced the pulmonary viral titer early during infection. The resting CD62Lhigh naive and memory populations first increased in cell numbers in the draining lymph nodes. Subsequently, memory cells accumulated more rapidly and to a greater extent in the lung lavage as compared with naive cells. Thus, effector cells are most effective against a localized virus infection, which correlates with their ability to rapidly distribute at the infected tissue site. The finding that similar numbers of naive Ag-specific CD8 T cells are not protective supports the view that qualitative differences between the two resting populations, the naive and the memory population, may play a major role in their protective value against disease.

Individual and combined effects of estrogen/progestin therapy and lovastatin on lipids and flow-mediated vasodilation in postmenopausal women with coronary artery disease

OBJECTIVES

We sought to examine the individual and combined effects of estrogen/progestin therapy versus lovastatin on lipids and flow-mediated vasodilation in postmenopausal women with heart disease.

BACKGROUND

Little information is available regarding the relative benefits of estrogen replacement therapy versus reductase inhibitors and the potential utility of their combination as lipid-lowering therapy for postmenopausal women.

METHODS

We conducted a randomized, double-blind, crossover trial in 24 postmenopausal women, each of whom received the following drug regimens during three consecutive six-week treatment periods: 1) hormone replacement (oral dose of 0.625 mg/day conjugated equine estrogens and 2.5 mg/day medroxyprogesterone acetate); 2) 20 mg lovastatin/day and 3) hormone replacement plus lovastatin.

RESULTS

Total and low density lipoprotein (LDL) cholesterol were significantly lowered and high density lipoprotein (HDL) cholesterol was significantly increased by all three regimens compared with baseline (p < 0.05). Lovastatin was more effective than estrogen/progestin in reducing LDL (p < 0.001), but estrogen/progestin was slightly more effective in increasing HDL. The hormone replacement and lovastatin regimen blocked the estrogen-associated increase in triglycerides. Hormone replacement (alone and with lovastatin) resulted in increases in brachial artery flow-mediated vasodilator capacity (p = 0.01 for both regimens) and the area under the curve (p = 0.016 and p = 0.005, respectively) compared with baseline. Percent dilation was greatest after the hormone replacement regimen, whereas the area under the curve was greatest after hormone replacement plus lovastatin (69% improvement vs. baseline).

CONCLUSIONS

In postmenopausal women with coronary disease and hyperlipidemia, conjugated equine estrogen produced significant improvements in lipids and vasodilator responses despite the concurrent administration of low dose medroxyprogesterone acetate. Low dose lovastatin produced greater reductions in LDL, but less dramatic improvements in vasodilator responses. Estrogen/progestin plus lovastatin may provide additional benefits via a greater reduction in the LDL/HDL ratio and attenuation of estrogen-associated hypertriglyceridemia. More information is needed about the safety and efficacy of such combinations of hormone replacement and reductase inhibitor therapy.

Migration kinetics and final destination of type 1 and type 2 CD8 effector cells predict protection against pulmonary virus infection

The requirements for CD8 T cells to provide protection against a localized virus infection in models of adoptive immunotherapy are not well defined. Here we investigated the protective value of defined in vitro-generated hemagglutinin (HA) peptide-specific primary CD8 T cell effectors from the clone 4 T cell receptor transgenic mice, secreting type 1 or type 2 cytokines, against pulmonary infection with whole influenza virus. Cytotoxic T lymphocytes producing type 1 and type 2 cytokine (Tc1 and Tc2) populations were equally cytolytic, but Tc1 effectors and not Tc2 effectors reduced the pulmonary virus titer early during infection. Host recovery mediated by Tc1 effectors was found to be independent of interferon gamma production. Tc2 effectors entered the lung with delayed kinetics as compared with Tc1 effectors, and after lung entry Tc2 effector cells did not localize near the infected airway epithelium as did Tc1 effectors but were found within clusters of inflammatory cells distant from the epithelium. We also show that the expression of several chemokine receptors was selectively regulated in the Tc1 and Tc2 subsets. Thus, the protective value of a CD8 cell population against pulmonary influenza virus infection is strongly correlated with its ability to exert its effector potential at the site of virus infection.

Transdermal delivery of estradiol in postmenopausal women with a novel topical aerosol

The objective of this study was to determine if a novel metered-dose topical aerosol (MDTA) formulation containing the new dermal penetration enhancer, padimate O, could enhance the transdermal delivery of estradiol to an extent that would result in clinically relevant plasma concentrations. The estradiol MDTA (with padimate O) was applied once daily at 0800 h to postmenopausal women for 9 days, and plasma estradiol and estrone was measured daily (24 h postapplication) by radioimmunoassay. The topical dose was administered as three 1 mg doses of estradiol, each applied as a single spray over 10 cm2 which were placed adjacent to each other on the subject's ventral forearm. None of the subjects tested showed any sign of skin irritation at the application site over the entire study period using the Draize irritation score. In four postmenopausal women (age 54-63 years, weight 67-93 kg) the mean estradiol level 24 h postapplication over the 9 day study period was 53 pg/mL. This result was significantly greater (p < 0.001) than the baseline value of 13 pg/mL. The mean estradiol/estrone ratio also rose significantly (p < 0.04) from a baseline value of 0.2 up to 0.8. We conclude that this novel MDTA formulation significantly enhances the transdermal delivery of estradiol to allow a clinically relevant dose of estradiol to be delivered in postmenopausal women with once daily dosing.

Enhanced transdermal delivery of sex hormones in swine with a novel topical aerosol

This study investigated the enhanced transdermal delivery of testosterone (Tes) and estradiol (E2) in swine in vivo with novel metered-dose topical aerosols containing the penetration enhancer padimate O (PadO) and predicted the dose deliverable in humans from the calculated drug flux across the skin. Weanling swine were catheterized and castrated under general anaesthesia and used as a conscious hypogonadal model. Tes and E2 (with and without PadO) were applied once, and venous blood samples were taken over 24 h. Tes and E2 plasma levels were determined by radioimmunoassay. After daily topical dosing of Tes for 6 days, the plasma Tes levels were determined and the transdermal flux was calculated by correcting the pseudo steady-state plasma concentration versus time profile with the clearance of an iv dose within the same swine. After a single application of the E2 aerosol over 30 cm2, or the Tes aerosol over 180 cm2, the mean AUC0-24 h when PadO was included in the spray was 14.1- and 2.0-fold greater than control, respectively (p < 0.03). After the sixth application of the Tes spray with PadO, the mean flux (+/-SE, n = 4) across swine skin in vivo was 2.12 +/- 0.35 microg/cm2.h, which gave a predicted flux in humans of 0.95 microg/cm2.h. From these data the expected plasma levels of Tes in hypogonadal men would compare well with the normal diurnal Tes profile in healthy men. These novel topical aerosols are capable of enhanced transdermal delivery of sex hormones in vivo, and they have the potential to deliver clinically relevant doses to humans.