Variability of TSNA in U.S. Tobacco and Moist Smokeless Tobacco Products.

Tobacco-specific nitrosamines (TSNAs) have been of concern to the public health community for decades and their reduction through agricultural practices, plant breeding, and tobacco processing has also been a decades-long industry effort. Despite those efforts, TSNAs, though lower, continue to be constituents of concern in tobacco products. This paper examines the TSNA levels of dark air-cured, dark fire-cured, and burley tobaccos purchased in the United States by U.S. Smokeless Tobacco Company LLC (USSTC) and of nine finished USSTC moist smokeless tobacco products. TSNA values of the incoming purchased tobaccos and the finished products showed considerable variability. For the incoming tobaccos, the coefficient of variation was generally more than 100 % for each tobacco type and for each of the measured TSNAs. The relative TSNA variability of the finished tobacco products was also considerable, averaging approximately 25 %. It was also found that the measured values for the finished products averaged well above the proposed FDA NNN proposed product standard of 1.0 µg/g dry weight. Because of the large variability in NNN values, products would have to average well below FDA's proposed product standard to be consistently compliant.

Pharmacological and electrophysiological characterization of AZSMO-23, an activator of the hERG K(+) channel.

BACKGROUND AND PURPOSE: We aimed to characterize the pharmacology and electrophysiology of N-[3-(1H-benzimidazol-2-yl)-4-chloro-phenyl]pyridine-3-carboxamide (AZSMO-23), an activator of the human ether-a-go-go-related gene (hERG)-encoded K(+) channel (Kv 11.1). EXPERIMENTAL APPROACH: Automated electrophysiology was used to study the pharmacology of AZSMO-23 on wild-type (WT), Y652A, F656T or G628C/S631C hERG, and on other cardiac ion channels. Its mechanism of action was characterized with conventional electrophysiology. KEY RESULTS: AZSMO-23 activated WT hERG pre-pulse and tail current with EC50 values of 28.6 and 11.2 µM respectively. At 100 µM, pre-pulse current at +40 mV was increased by 952 ± 41% and tail current at -30 mV by 238 ± 13% compared with vehicle values. The primary mechanism for this effect was a 74.5 mV depolarizing shift in the voltage dependence of inactivation, without any shift in the voltage dependence of activation. Structure-activity relationships for this effect were remarkably subtle, with close analogues of AZSMO-23 acting as hERG inhibitors. AZSMO-23 blocked the mutant channel, hERG Y652A, but against another mutant channel, hERG F656T, its activator activity was enhanced. It inhibited activity of the G628C/S631C non-inactivating hERG mutant channel. AZSMO-23 was not hERG selective, as it blocked hKv 4.3-hKChIP2.2, hCav 3.2 and hKv 1.5 and activated hCav 1.2/ß2/α2δ channels. CONCLUSION AND IMPLICATIONS: The activity of AZSMO-23 and those of its close analogues suggest these compounds may be of value to elucidate the mechanism of type 2 hERG activators to better understand the pharmacology of this area from both a safety perspective and in relation to treatment of congenital long QT syndrome.

Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays.

Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies - radioligand-binding or automated electrophysiology - was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost.

Validation of an in vitro contractility assay using canine ventricular myocytes.

Measurement of cardiac contractility is a logical part of pre-clinical safety assessment in a drug discovery project, particularly if a risk has been identified or is suspected based on the primary- or non-target pharmacology. However, there are limited validated assays available that can be used to screen several compounds in order to identify and eliminate inotropic liability from a chemical series. We have therefore sought to develop an in vitro model with sufficient throughput for this purpose. Dog ventricular myocytes were isolated using a collagenase perfusion technique and placed in a perfused recording chamber on the stage of a microscope at ~36 °C. Myocytes were stimulated to contract at a pacing frequency of 1 Hz and a digital, cell geometry measurement system (IonOptix™) was used to measure sarcomere shortening in single myocytes. After perfusion with vehicle (0.1% DMSO), concentration-effect curves were constructed for each compound in 4-30 myocytes taken from 1 or 2 dog hearts. The validation test-set was 22 negative and 8 positive inotropes, and 21 inactive compounds, as defined by their effect in dog, cynolomolgous monkey or humans. By comparing the outcome of the assay to the known in vivo contractility effects, the assay sensitivity was 81%, specificity was 75%, and accuracy was 78%. With a throughput of 6-8 compounds/week from 1 cell isolation, this assay may be of value to drug discovery projects to screen for direct contractility effects and, if a hazard is identified, help identify inactive compounds.

Implications of the proposed thyroid fine-needle aspiration category of "follicular lesion of undetermined significance": A five-year multi-institutional analysis.

National Cancer Institute State of the Science Conference on thyroid fine-needle aspiration (FNA) summarized diagnostic terminology. Six diagnostic categories were proposed including "follicular lesion of undetermined significance" (FLUS). FLUS was defined as findings neither convincingly benign nor sufficiently atypical for a diagnosis of "follicular neoplasm" or "suspicious for malignancy." It was proposed that this category represent less than 7% of thyroid FNAs. A search of the cytology records at three University Hospitals was performed for the term FLUS or older equivalent terms. Usage of FLUS was compared between institutions and among pathologists. Surgical pathology outcome for FLUS cases was determined. Twenty-eight pathologists evaluated 6,872 cases at the three institutions. Use of FLUS varied among pathologists (2.5 to 28.6%). Frequency of use of FLUS among institutions varied from 3.3 to 14.9%. FLUS cases [127 of 673 (18.9%)] underwent surgical exploration with malignancy identified in 36 cases (28.3%) undergoing resection. Use of FLUS varied substantially among pathologists and institutions. FLUS category requires more rigorously defined morphologic criteria for it to become a useful guide in clinical management.

Characterisation and evaluation of UK websites on attention deficit hyperactivity disorder.

OBJECTIVES: To identify, characterise and evaluate UK websites providing information about attention deficit hyperactivity disorder (ADHD) and its pharmacological management. DESIGN: Cross-sectional survey of websites identified by entering "ADHD" into five search engines. DATA SOURCE: 48 websites. MAIN OUTCOME MEASURES: Each website was scored against 26 criteria using a bespoke instrument to evaluate (a) quality of information on the disorder and its drug treatment and (b) physical characteristics of the site. RESULTS: Most sites (n = 22) were hosted by charities and support groups, 12 were by commercial organisations, nine were from government or professional bodies, and five were categorised as miscellaneous. Mean total scores per host category ranged from 18.8 to 21 out of 46, with mean (SD) scores of 5.5 (4.2) out of 28 for content and 14.8 (3.0) out of 18 for physical properties. The government/professional sites scored highest for both content and physical properties. Descriptions of the disorder and its drug treatment were poor and lacking in detail. Although most sites mentioned stimulants, only eight discussed atomoxetine and described how both types of drug worked. Ten sites provided detailed information about side effects. The role of different stimulant brands and formulations was discussed on six sites. Authorship details were generally vague. Physical properties related to navigation and layout performed well. Only four sites used language deemed suitable for consumer-orientated health information. CONCLUSIONS: Information on UK websites about drug treatment for ADHD is basic and incomplete. Websites by government and professional bodies perform better than those in other categories.

Molecular genetic evidence supporting the neoplastic nature of stromal cells in 'fibrosis' after chemotherapy for testicular germ cell tumours.

A residual retroperitoneal mass containing only fibrosis and necrosis is present in 40-52% of patients with advanced testicular germ cell tumours after chemotherapy. The biological nature and genetic characteristics of the stromal cells in these residual masses have not been adequately investigated. Laser-microdissected stromal cells from 27 patients who underwent retroperitoneal lymph node dissection after chemotherapy for metastatic testicular germ cell tumour were analysed. Allelic loss in the stromal cells of fibrosis was present at one or more of the ten microsatellite DNA loci examined in 23 (85%) of the cases. Chromosome arm 12p anomalies, the hallmark of germ cell neoplasia, were present in nine (33%) cases. The high frequency of allelic losses and chromosome arm 12p anomalies in the stromal cells from residual retroperitoneal fibrous masses after chemotherapy for testicular germ cell tumours suggests that the stromal cells are derived from the same tumour progenitor cells as the pre-existing metastatic germ cell tumour.

Smoke composition and predicting relationships for international commercial cigarettes smoked with three machine-smoking conditions.

The study objectives were to determine the effects of smoking machine puffing parameters on mainstream smoke composition and to express those effects as predicting relationships. Forty-eight commercial Philip Morris USA and Philip Morris International cigarettes from international markets and the 1R4F reference cigarette were machine-smoked using smoking conditions defined by the International Organization of Standardization (ISO), the Massachusetts Department of Public Health (MDPH), and Health Canada (HC). Cigarette tobacco fillers were analyzed for nitrate, nicotine, tobacco-specific nitrosamines (TSNA), and ammonia. Mainstream yields for tar and 44 individual smoke constituents and "smoke pH" were determined. Cigarette constituent yields typically increased in the order ISO

Non-genomic regulation of intermediate conductance potassium channels by aldosterone in human colonic crypt cells.

BACKGROUND: Aldosterone has a rapid, non-genomic, inhibitory effect on macroscopic basolateral K(+) conductance in the human colon, reducing its capacity for Cl(-) secretion. The molecular identity of the K(+) channels constituting this aldosterone inhibitable K(+) conductance is unclear. AIM: To characterise the K(+) channel inhibited by aldosterone present in the basolateral membrane of human colonic crypt cells. METHODS: Crypts were isolated from biopsies of healthy sigmoid colon obtained during colonoscopy. The effect of aldosterone on basolateral K(+) channels, and the possible involvement of Na(+):H(+) exchange, were studied by patch clamp techniques. Total RNA from isolated crypts was subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) using primers specific to intermediate conductance K(+) channels (KCNN4) previously identified in other human tissues. RESULTS: In cell attached patches, 1 nmol/l aldosterone significantly decreased the activity of intermediate conductance (27 pS) K(+) channels by 31%, 53%, and 54% after 1, 5 and 10, minutes, respectively. Increasing aldosterone concentration to 10 nmol/l produced a further 56% decrease in channel activity after five minutes. Aldosterone 1-10 nmol/l had no effect on channel activity in the presence of 20 micro mol/l ethylisopropylamiloride, an inhibitor of Na(+):H(+) exchange. RT-PCR identified KCNN4 mRNA, which is likely to encode the 27 pS K(+) channel inhibited by aldosterone. CONCLUSION: Intermediate conductance K(+) channels (KCNN4) present in the basolateral membranes of human colonic crypt cells are a target for the non-genomic inhibitory effect of aldosterone, which involves stimulation of Na(+):H(+) exchange, thereby reducing the capacity of the colon for Cl(-) secretion.

Pulmonary function in nonsmokers following exposure to sidestream cigarette smoke.

Ten healthy male and 10 healthy female, "never-smoking" subjects (ages 21-50) participated in a 5-day environmental room study to determine if an acute exposure to a high level of fresh diluted sidestream smoke (FDSS) would alter pulmonary function. On Monday, Tuesday, Thursday and Friday, the twenty subjects sat in an environmental room for 7.33 hours and were exposed to filtered and humidified air. On Wednesday, the twenty subjects were exposed in an environmental room for 7.33 hours to an average respirable suspended particle (RSP) concentration of 179 micrograms per m3 of FDSS generated by machine smoking Kentucky 1R4F reference cigarettes. This level of FDSS is 3.3 times the 95th percentile concentration of workplace environmental tobacco smoke exposure levels previously measured in the US. FVC and FEV1 decreased approximately 1.6% (p < 0.05) in both males and females after exposure. Similarly, PEF decreased approximately 1.3% (p < 0.03) following exposure. The observed decrease in pulmonary function was consistent with a "stress" related norepinephrine-induced alteration in blood flow leading to transient bronchoconstriction. Alternatively, a cholinergic reflex due to activation of bronchopulmonary C fibers may have also played a role in the transient bronchoconstriction. These small exposure-related decrements in pulmonary function were reversible.

Urinary thromboxane, prostacyclin, cortisol, and 8-hydroxy-2'-deoxyguanosine in nonsmokers exposed and not exposed to environmental tobacco smoke.

This study tested the hypotheses that (1) increased platelet aggregation, as measured by 2,3-dinor-thromboxane B(2) (Tx-M) and 2,3-dinor-6-keto-prostaglandin F(1alpha) (PGI-M), and (2) increased oxidative stress, as measured by 8-Hydroxy-2'-deoxyguanosine (8-OHdG), would occur in ETS-exposed nonsmokers as compared with non-ETS-exposed nonsmokers. The concentrations of the stable urinary metabolites of thromboxane (Tx-M) and prostacyclin (PGI-M), cortisol and 8-OHdG were measured in a 24-h urine sample from 3 groups of subjects: 21 nonsmokers with minimal (15 min or less per day) ETS exposure (termed non-ETS-exposed), 22 nonsmokers with at least 5 h per day of ETS exposure (termed ETS-exposed), and 20 cigarette smokers who served as a positive control group. The self-reported levels of ETS exposure were verified by personal air monitors. As compared with either group of nonsmokers, cigarette smokers excreted significantly more urinary Tx-M. Non-ETS-exposed nonsmokers showed a statistically significantly higher level of urinary Tx-M over that seen in nonsmokers with considerably more ETS exposure. Urinary concentrations of PGI-M were marginally higher in the smokers and did not differ between the nonsmoker groups. Nonsmokers exposed to at least five h of ETS per day did not have significantly higher excretion of 8-OHdG than non-ETS-exposed nonsmokers. The results from this study suggest that platelet aggregation, as measured by the thromboxane metabolite Tx-M and prostacyclin metabolite PGI-M, is not associated with ETS exposure. Therefore, platelet aggregation is not a plausible or quantitatively consistent mechanism to explain the nonlinear dose-response hypothesis of cardiovascular disease and ETS exposure.

A comparison of the mainstream smoke chemistry and mutagenicity of a representative sample of the US cigarette market with two Kentucky reference cigarettes (K1R4F and K1R5F).

The incorporation of technologies into cigarettes such as filters, filter ventilation, porous cigarette papers, expanded tobacco and reconstituted tobacco sheet has resulted in cigarettes with a wide range of "tar" yields. The objectives of this study were to characterize the US cigarette market according to "tar" category (i.e. full flavor, FF; full flavor low tar, FFLT; or ultra low tar, ULT) and to determine whether the Kentucky reference cigarettes K1R4F and K1R5F are representative of FFLT and ULT cigarettes, respectively. As a means of characterization and comparison, the mainstream smoke from a representative sample of commercially available cigarettes from each market segment and the K1R4F and K1R5F Kentucky reference cigarettes was analyzed for the presence and level of 18 selected chemical constituents. In addition, a measure of the mutagenic activity of the mainstream smoke condensate from these cigarettes was determined using an Ames Salmonella mutagenicity assay. All cigarettes were smoked according to US Federal Trade Commission (FTC) guidelines. Results indicated that, overall, mainstream smoke constituent levels are well predicted by FTC "tar" yield--constituent levels increased as "tar" delivery increased. Based on the selected analytes measured in mainstream smoke, the K1R4F reference cigarette was generally representative of the FFLT segment of the US cigarette market. The K1R5F reference cigarette was representative of the ULT segment of the US cigarette market for cigarettes with "tar" deliveries approximate to it. In terms of mutagenic activity, a direct relationship was also demonstrated on a per cigarette basis-revertants per cigarette increased with increasing "tar" delivery. There was a weak tendency (R-square = 0.12, P = 0.08) for specific activity (revertants/mg "tar") to increase with decreasing "tar" yield-lower "tar" products had a slightly higher specific activity. No significant differences (P > 0.05) were observed when the specific activities of the condensates from the K1R4F and K1R5F reference cigarettes were compared to the market segments that they were designed to represent, FFLT and ULT, respectively. Overall, these results support the use of the K1R4F and the K1R5F as acceptable reference cigarettes for comparative mutagenicity and smoke chemistry studies of cigarettes available on the US market.

Right ventricular systolic pressure load alters myocyte maturation in fetal sheep.

The effects of right ventricular (RV) systolic pressure (RVSP) load on fetal myocyte size and maturation were studied. Pulmonary artery (PA) pressure was increased by PA occlusion from mean 47.4 +/- 5.0 (+/-SD) to 71 +/- 13.6 mmHg (P < 0.0001) in eight RVSP-loaded near-term fetal sheep for 10 days. The maximal pressure generated by the RV with acute PA occlusion increased after RVSP load: 78 +/- 7 to 101 +/- 15 mmHg (P < 0.005). RVSP-load hearts were heavier (44.7 +/- 8.4 g) than five nonloaded hearts (31.8 +/- 0.2 g; P < 0.03); heart-to-body weight ratio (10.9 +/- 1.1 and 6.5 +/- 0.9 g/kg, respectively; P < 0.0001). RVSP-RV myocytes were longer (101.3 +/- 10.2 microm) than nonloaded RV myocytes (88.2 +/- 8.1 microm; P < 0. 02) and were more often binucleated (82 +/- 13%) than nonloaded myocytes (63 +/- 7%; P < 0.02). RVSP-loaded myocytes had less myofibrillar volume than did nonloaded hearts (44.1 +/- 4.4% and 56. 1 +/- 2.6%; P < 0.002). We conclude that RV systolic load 1) leads to RV myocyte enlargement, 2) has minor effects on left ventricular myocyte size, and 3) stimulates maturation (increased RV myocyte binucleation). Myocyte volume data suggest that RV systolic loading stimulates both hyperplastic and hypertrophic growth.

Hemodynamic changes in pregnancy.

The basic mechanisms that underlie alterations in the physiology of pregnancy are virtually unknown. Basal oxygen consumption increases by some 50 mL/min in pregnant women at term. Blood volume increases gradually over gestation as does red cell mass. Cardiac output increases by some 50% by mid-third trimester. Stroke volume and heart rate increase over the course of pregnancy with heart rate increasing gradually until term. The heart of the pregnant woman remodels dramatically in the first few weeks of pregnancy; end diastolic volume increases. Stroke volume is augmented by the increase in end diastolic volume and maintenance of ejection fraction through a possible increase in contractile force. Systolic and diastolic blood pressures drop during normal pregnancy. There is evidence of blood vessel remodeling in all vessels. Venous compliance and venous blood volume are increased. Renal plasma flow increases by some 70% in pregnancy with glomerular filtration rate increasing by 50% by unknown mechanisms. The complex hormonal environment is changing throughout pregnancy. In summary, under the influence of circulating chemical mediators blood flow is redistributed to the uterus, breast, and kidney.

Gap junction intercellular communication and cytotoxicity in normal human cells after exposure to smoke condensates from cigarettes that burn or primarily heat tobacco.

Heating tobacco, rather than burning it, reduces tobacco combustion and pyrolysis products. This study tested the hypothesis that the simplified smoke chemistry of a cigarette which primarily heats tobacco (TOB-HT) significantly reduces the potential to alter the structure or function of cellular plasma membranes relative to low "tar" 1R4F and ultra low "tar" lR5F Kentucky reference cigarettes which burn tobacco. Gap junction intercellular communication (GJIC) and lactate dehydrogenase release (LDH) were used to quantify functional and structural changes to the plasma membrane, respectively. Cigarette smoke condensate (CSC) from the mainstream smoke of TOB-HT, lR4F and 1R5F cigarettes were compared in the GJIC and LDH release assays following a 1-hr exposure in vitro. Human bronchial/tracheal epithelial cells, coronary artery endothelial cells, coronary artery smooth muscle cells, foreskin keratinocytes and the WB-344 rat liver epithelial cell line were studied. TOB-HT did not inhibit GJIC in any of the human cell types tested (P0.05) at concentrations where 1R4F and lR5F did inhibit GJIC (P<0.05). TOB-HT did not elevate LDH release (P0.05) when tested at concentrations where lR4F and lR5F did elevate LDH release (P<0.05). Our results suggest that CSC from TOB-HT cigarettes is less damaging to the structure or function of the cellular plasma membranes of a variety of human cell lines than CSC from 1R4F and 1R5F tobacco burning reference cigarettes.

Regulation of renal adenosine A(1) receptors: effect of dietary sodium chloride.

The influence of dietary NaCl on the regulation of renal adenosine A(1) receptors was investigated in the rat. Renal membranes from rats fed on a diet low (0.04%) in NaCl showed a 46% increase in B(max) for the binding of [3H]-1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX), a selective adenosine A(1) receptor antagonist, compared to membranes from rats fed on a normal diet (0.4% NaCl). Conversely, a high NaCl diet (4.0%) resulted in a 37% decrease in B(max). Levels of renal adenosine A(1) receptor mRNA were 65% lower in rats on a high salt diet. Autoradiographic studies showed that, for the inner medullary collecting ducts, a low NaCl diet resulted in a 30% increase in [3H]DPCPX binding with a 39% decrease noted in rats maintained on a high salt diet. The results indicate that changes in adenosine A(1) receptor density may represent a novel mechanism whereby the kidneys adapt to changes in salt load.

Myocardial blood flow and coronary reserve in chronically anemic fetal lambs.

Chronic fetal anemia produces large compensatory increases in coronary blood flow in the near-term fetal lamb. To determine if increased coronary flow in anemic fetuses is associated with decreased coronary flow reserve or, alternatively, an increase in coronary conductance, we measured maximal coronary artery conductance during adenosine infusion before and during anemia. Isovolemic hemorrhage over 7 days reduced hematocrit from 30.6 +/- 2. 7 to 15.8 +/- 2.4% (P < 0.02) and the oxygen content from 7.3 +/- 1. 4 to 2.6 +/- 0.4 ml/dl (P < 0.001). Coronary blood flow increased from control (202 +/- 60) to 664 +/- 208 ml. min(-1). 100 g(-1) with adenosine to 726 +/- 169 ml. min(-1). 100 g(-1) during anemia and to 1,162 +/- 250 ml. min(-1). 100 g(-1) (left ventricle) during anemia with adenosine infusion (all P < 0.001). Coronary conductance, determined during maximal vasodilation, was 18.2 +/- 7.7 before and 32.8 +/- 11.9 ml. min(-1). 100 g(-1). mmHg(-1) during anemia (P < 0. 001). Coronary reserve, the difference between resting and maximal myocardial blood flow interpolated at 40 mmHg, was unchanged in control and anemic fetuses (368 +/- 142 and 372 +/- 201 ml/min). Because hematocrit affects viscosity, anemic fetuses were transfused with blood to acutely increase the hematocrit back to control, and conductance was remeasured. Coronary blood flow decreased 57.3 +/- 18.9% but was still 42.6 +/- 18.9% greater than control. We conclude that in chronically anemic fetal sheep coronary conductance is increased and coronary reserve is maintained, and this is attributed in part to angiogenesis as well as changes in viscosity.

The sequential effects of estrogen administration and hypertension on cardiac function in ewes.

OBJECTIVE: Our objective was to study the effect of estrogen administration and moderate hypertension on left ventricular size, pump function, and contractility in chronically instrumented ewes. STUDY DESIGN: Ewes were either given 0.06 mg/kg 17beta-estradiol intramuscularly (n = 8) or were made hypertensive (n = 6) by inflation of an occluder around the aorta and were studied weekly. After 3 weeks each ewe received the opposite treatment. RESULTS: Estrogen administration caused an increase in left ventricular chamber size at a given pressure, fractional shortening (21.9% +/- 2.9% to 28.5% +/- 3.7%), and stroke volume (1.4 +/- 0.3 mL/kg to 1.6 +/- 0.3 mL/kg). Subsequent hypertension further increased left ventricular size at a given pressure but decreased fractional shortening (20.0% +/- 4.4%) and stroke volume (1.3 +/- 0.3 mL/kg). With hypertension first, there was no left ventricular enlargement, even with subsequent estrogen administration, and there were no changes in left ventricular pump function. End-systolic pressure and stress-dimension relationships did not change with either treatment. The end-systolic wall stress-fractional shortening relationship was likewise unchanged, suggesting that neither treatment changed contractility. CONCLUSIONS: The left ventricle previously exposed to hypertension does not remodel when exposed to estrogen, and cardiac pump function decreases when the estrogen enlarged heart is faced with moderate, subacute hypertension.