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The evolutionary processes that underlie the marked sensitivity of small cell lung cancer (SCLC) to chemotherapy and rapid relapse are unknown1–3. Here we determined tumour phylogenies at diagnosis and throughout chemotherapy and immunotherapy by multiregion sequencing of 160 tumours from 65 patients. Treatment-naive SCLC exhibited clonal homogeneity at distinct tumour sites, whereas first-line platinum-based chemotherapy led to a burst in genomic intratumour heterogeneity and spatial clonal diversity. We observed branched evolution and a shift to ancestral clones underlying tumour relapse. Effective radio- or immunotherapy induced a re-expansion of founder clones with acquired genomic damage from first-line chemotherapy. Whereas TP53and RB1alterations were exclusively part of the common ancestor, MYCfamily amplifications were frequently not constituents of the founder clone. At relapse, emerging subclonal mutations affected key genes associated with SCLC biology, and tumours harbouring clonal CREBBP/EP300alterations underwent genome duplications. Gene-damaging TP53alterations and co-alterations of TP53missense mutations with TP73, CREBBP/EP300or FMN2were significantly associated with shorter disease relapse following chemotherapy. In summary, we uncover key processes of the genomic evolution of SCLC under therapy, identify the common ancestor as the source of clonal diversity at relapse and show central genomic patterns associated with sensitivity and resistance to chemotherapy.

Die kardiale Sarkoidose ist in ihrer klinischen Ausprägung variabel und geprägt von Herausforderungen in Diagnostik, Therapie und Prognoseeinschätzung. Durch eine größere Aufmerksamkeit und Fortschritte in der apparativen Diagnostik ist eine steigende Inzidenz der Erkrankung zu beobachten. Dieser Beitrag stellt Entwicklungen und notwendiges Hintergrundwissen basierend auf den aktuellen Leitlinien dar. Zur Veranschaulichung dient exemplarisch eine Kasuistik eines 50-jährigen Patienten mit plötzlich aufgetretener ventrikulärer Tachykardie.

Hintergrund: Im Jahr 2021 wurde eine internationale (ERS [Europäische Respiratorische Gesellschaft]) Leitlinie (LL) zur Behandlung der Sarkoidose publiziert. Im Jahr 2023 erfolgte eine deutsche S2k-LL zu dieser Thematik. Fragestellung: Er erfolgt eine Bewertung der beiden neuen Leitlinien bezüglich Stärken und Schwächen insbesondere im Hinblick auf Anwendung in der klinischen Routine Material und Methoden: Es erfolgte eine Analyse der beiden Leitlinien zur Behandlung der Sarkoidose in Hinsicht auf die therapeutischen Fragestellungen und gegebenen Empfehlungen. Ergebnisse: In beiden Leitlinien wurden wichtige therapeutischen Fragestellungen nach dem GRADE-System mit entsprechender Graduierung beantwortet. Beide LL stimmen mit den Indikationsgründen zur Einleitung einer systemischen Steroidtherapie überein und berücksichtigen Prednisolon als Erstlinientherapie. Im Falle eines Progresses werden weitere Immunsuppressiva sowie Biologika, allein oder in Kombination mit Prednisolon, als Alternative empfohlen. Die Bewahrung bzw. Besserung der Lebensqualität der Patienten sowie der Organfunktion wird von beiden LL als zentrales Ziel der Behandlung betrachtet. Einschränkungen beider LL liegen an fehlenden Empfehlungen zur Behandlung der Komplikationen, zur Transplantationslistung und zu nichtmedikamentösen Maßnahmen. Schlussfolgerung: Beide Leitlinien zur Behandlung der Sarkoidose geben einen sehr guten Überblick über die vorhandene Evidenz einzelner medikamentöser Therapien. Gravierende Abweichungen lassen sich nicht feststellen.

Lurbinectedin is a synthetic marine-derived anticancer agent that acts as a selective inhibitor of oncogenic transcription. Lurbinectedin monotherapy (3·2 mg/m2every 3 weeks) received accelerated approval from the US Food and Drug Administration on the basis of efficacy in patients with small-cell lung cancer (SCLC) who relapsed after first-line platinum-based chemotherapy. The ATLANTIS trial assessed the efficacy and safety of combination lurbinectedin and the anthracycline doxorubicin as second-line treatment for SCLC.

Patients with metastatic NSCLC (mNSCLC) treated with immune checkpoint inhibitors in clinical practice may often not meet the strict inclusion criteria of clinical trials. Our aim was to assess the trial eligibility of patients with mNSCLC treated with pembrolizumab monotherapy in real-world and to compare the outcome of “trial-ineligible” and “potentially trial-eligible” patients.

IMPORTANCE: Paraneoplastic neurological syndromes are associated with neuronal autoantibodies, and some of these autoantibodies are associated with neuropsychological symptoms. The most common underlying tumor is lung cancer. The association of neuronal autoantibodies with cognitive deficits has not been systematically investigated in patients with small cell lung cancer (SCLC) and non–small cell lung cancer (NSCLC). OBJECTIVE: To assess the frequency of neuronal autoantibodies in patients with lung cancer and analyze their association with cognitive function. DESIGN, SETTING, AND PARTICIPANTS: This prospective, cross-sectional study included 167 patients with lung cancer (both SCLC and NSCLC) recruited at a single lung cancer center in Berlin, Germany, between June 2015 and April 2016. Detailed neuropsychological testing was performed in a carefully selected subgroup of 97 patients (from which patients with potential confounding factors were excluded). Investigators were blinded to patients’ autoantibody status and cognitive test results. Data were analyzed from May 2016 to December 2019. MAIN OUTCOMES AND MEASURES: Prevalence of neuronal autoantibodies and their association with cognitive impairment. The evaluation of autoantibodies as potential risk factors for cognitive impairment was performed using bayesian logistic regression models. RESULTS: Among 167 patients with lung cancer (median age, 66.0 years [interquartile range, 59.0-72.0 years]; 105 men [62.9%]), 127 had NSCLC, and 40 had SCLC. Brain-directed autoantibodies were detected in 61 of 167 patients (36.5%); 33 patients (19.8%) had known autoantibodies and 28 patients (16.8%) had autoantibodies against currently unknown antigens that were detected through immunohistochemical analysis. Cognitive impairment was found in 65 of 97 patients (67.0%). Among patients with SCLC, the odds of cognitive impairment for those with any autoantibodies was 11-fold higher (odds ratio [OR], 11.0; 95% credible interval [CrI], 1.2-103.6) than that of autoantibody-negative patients, and the increased odds were independent of age, sex, and neurological deficit. Among patients with NSCLC, those with immunoglobin A autoantibodies targeting the N-methyl-d-aspartate receptor had a relevantly increased odds of verbal memory deficits (OR, 182.8; 95% CrI, 3.1-10 852.4). Autoantibodies against currently unknown antigens were also associated with increased odds of cognitive impairment (OR, 2.8; 95% CrI, 0.6-12.1). CONCLUSIONS AND RELEVANCE: In this prospective, cross-sectional study, more than one-third of patients with lung cancer had neuronal autoantibodies that were found to be associated with cognitive impairment. These autoantibodies might represent a potentially treatable mechanism of immune-mediated cognitive impairment among patients with lung cancer.

Robust data on the outcome of MET-aberrant NSCLC with nontargeted therapies are limited, especially in consideration of the heterogeneity of MET-amplified tumors (METamp).

Programmed death-ligand 1 expression currently represents the only validated predictive biomarker for immune checkpoint inhibition in metastatic NSCLC in the clinical routine, but it has limited value in distinguishing responses. Assessment of KRASand TP53mutations (mut) as surrogate for an immunosupportive tumor microenvironment (TME) might help to close this gap.

Dieser Fallbericht beschreibt das sehr seltene gleichzeitige Auftreten einer rheumatoiden Arthritis und einer Granulomatose mit Polyangiitis mit der einzigen Organmanifestation lebensbedrohlicher Lungenkavitäten beidseitig. Die Therapie erfolgte aufgrund der Akuität der Erkrankung primär mit Cyclophosphamid-Infusionen und hoch dosierten Glukokortikoiden, im weiteren Verlauf mit hoch dosiertem Methotrexat. Auch bei Neueinleitung einer konventionellen rheumatologischen Basistherapie scheint eine routinemäßige Thoraxaufnahme sinnvoll zu sein, da in relevanter Häufigkeit therapieentscheidende Veränderungen gesehen werden. Das Auftreten beider Autoimmunerkrankungen könnte auf gemeinsame genetische Prädispositionen zurückzuführen sein.

ROS1rearrangements are found in 1% of lung cancer patients. Therapeutic efficacy of crizotinib in this subset has been shown in early phase trials in the United States and East Asia. Here we present data on efficacy and safety of a prospective phase II trial evaluating crizotinib in European ROS1-positive patients (EUCROSS).

Although KRASmutations in NSCLC have been considered mutually exclusive driver mutations for a long time, there is now growing evidence that KRAS-mutated NSCLC represents a genetically heterogeneous subgroup. We sought to determine genetic heterogeneity with respect to cancer-related co-mutations and their correlation with different KRASmutation subtypes.

Despite the widespread prevalence of hyponatremia and its deleterious effects on patients, it is often overlooked and consequently undertreated. This set of four cases provides practical advice on how to identify, diagnose, and treat patients with syndrome of inappropriate antidiuretic hormone (SIADH). The first steps that a physician should take when diagnosing a patient with hyponatremia are to assess the severity of neurological symptoms, and check the patient’s volemic status in order to determine whether emergency treatment with hypertonic saline is indicated. Laboratory tests are necessary for the diagnosis of SIADH, but, in severe, symptomatic cases of hyponatremia, patients need treatment before the results of laboratory tests can be obtained. In this series, Case 1 demonstrates how awareness of hyponatremia led to early diagnosis and treatment. Case 2 demonstrates how multiple causes of hyponatremia can be diagnosed and managed sequentially. Case 3 illustrates how a patient with severe symptoms should be treated while waiting for laboratory test results to confirm diagnosis. Case 4 examines how the priorities of a patient should inform the management of their chronic SIADH, using palliative care of a patient with small-cell lung cancer as an example. There are several factors that clinicians should consider when making treatment decisions, including signs and symptoms, risks and benefits of different treatments, psychosocial factors, and the patient’s wishes. All the available treatment options have a place in the management of patients with SIADH, and a physician should individualize decisions based on a patient’s needs and priorities.

In ADAURA, adjuvant osimertinib significantly improved disease-free survival versus placebo in resected stage IB to IIIA EGFR-mutated NSCLC. We report in-depth analyses of three-year safety, tolerability, and health-related quality of life (HRQoL) from ADAURA.

To offer patients with EGFRmutation–positive advanced NSCLC appropriate EGFR tyrosine kinase inhibitor treatment, mutation testing of tumor samples is required. However, tissue/cytologic samples are not always available or evaluable. The large, noninterventional diagnostic ASSESS study (NCT01785888) evaluated the utility of circulating free tumor-derived DNA (ctDNA) from plasma for EGFRmutation testing.

Rearrangements of RETare rare oncogenic events in patients with non–small cell lung cancer (NSCLC). While the characterization of Asian patients suggests a predominance of nonsmokers of young age in this genetically defined lung cancer subgroup, little is known about the characteristics of non-Asian patients. We present the results of an analysis of a European cohort of patients with RETrearranged NSCLC.

The cause of sarcoidosis is unclear. Evidence suggests that there is a genetic susceptibility toward the disease. In this study, we examined whether haplotypes of vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 and VEGFR-2 are associated with the onset or the course of sarcoidosis.

The molecular mechanisms that mediate gram-negative sepsis-associated myocardial dysfunction remain elusive. Myocardial expression of inflammatory mediators is Toll-like receptor 4 (TLR4) dependent. However, it remains to be elucidated whether TLR4, expressed on cardiac myocytes, mediates impairment of cardiac contractility after lipopolysaccharide (LPS) application. Cardiac myocyte contractility, measured as sarcomere shortening of isolated cardiac myocytes from C3H/HeJ (with nonfunctional TLR4) and C3H/HeN (control), were recorded at stimulation frequencies between 0.5 and 10 Hz and after incubation with 1 and 10 μg/mL LPS for up to 8 h. Control cells treated with LPS were investigated with and without a competitive LPS inhibitor (E5564) and a specific inducible nitric oxide synthase (iNOS) inhibitor S-methylisothiourea. In control mice, LPS reduced sarcomere shortening amplitude and prolonged duration of relaxation, whereas sarcomere shortening of C3H/HeJ cells was insensitive to LPS. NFκB and iNOS were upregulated after LPS application in control mice compared with C3H/HeJ. Inhibition of TLR4 by E5564 as well as inhibition of iNOS prevented the influence of LPS on contractile activity in control myocytes. LPS-dependent suppression of cardiac myocyte contractility was significantly blunted in C3H/HeJ mice. Competitive inhibition of functional TLR4 with E5564 protects cardiac myocyte contractility against LPS. These findings suggest that TLR4, expressed on cardiac myocytes, contributes to sepsis-induced myocardial dysfunction. E5564, currently under investigation in two clinical phase II trials, seems to be a new therapeutic option for the treatment of myocardial dysfunction in sepsis associated with endotoxemia.

Physiological effects of estrogen on myocardium are mediated by two intracellular estrogen receptors, ERα and ERβ, that regulate transcription of target genes through binding to specific DNA target sequences. To define the role of ERβ in the transcriptional activation of both endothelial (eNOS) and inducible nitric oxide synthase (iNOS) in cardiac myocytes, we used the complete ERβ‐specific antagonist R,R‐tetrahydrochrysene (R,R‐THC). R,R‐THC inhibited activation of iNOS/eNOS promoter‐luciferase reporter constructs (iNOS/eNOS‐Luc) in a dose‐dependent fashion in COS7 cells selectively transfected with ERβ, but failed to influence ERα‐mediated increase of iNOS/eNOS‐Luc. In neonatal rat cardiomyocytes transfected with eNOS‐Luc or iNOS‐Luc, incubation with 17β‐estradiol (E2, 10−8M) for 24 h stimulated expression of eNOS and iNOS. R,R‐THC (10−5M) completely inhibited this effect. Furthermore, eNOS and iNOS protein expression in cardiac myocytes induced by E2 was completely blocked by R,R‐THC as shown by immunoblot analysis. Taken together, these results show that ERβ mediates transcriptional activation of eNOS and iNOS by E2.

Physiological effects of estrogen on myocardium are mediated by two intracellular estrogen receptors, ERα and ERβ, that regulate transcription of target genes through binding to specific DNA target sequences. To define the role of ERβ in the transcriptional activation of both endothelial (eNOS) and inducible nitric oxide synthase (iNOS) in cardiac myocytes, we used the complete ERβ-specific antagonist R, R-tetrahydrochrysene ( R, R-THC). R, R-THC inhibited activation of iNOS/eNOS promoter-luciferase reporter constructs (iNOS/eNOS-Luc) in a dose-dependent fashion in COS7 cells selectively transfected with ERβ, but failed to influence ERα-mediated increase of iNOS/eNOS-Luc. In neonatal rat cardiomyocytes transfected with eNOS-Luc or iNOS-Luc, incubation with 17β-estradiol (E2, 10 −8M) for 24 h stimulated expression of eNOS and iNOS. R, R-THC (10 −5M) completely inhibited this effect. Furthermore, eNOS and iNOS protein expression in cardiac myocytes induced by E2 was completely blocked by R, R-THC as shown by immunoblot analysis. Taken together, these results show that ERβ mediates transcriptional activation of eNOS and iNOS by E2.

The effects of angiotensin‐converting enzyme (ACE) inhibition and angiotensin type 1 (AT1) receptor blockade on insulin‐like growth factor‐I (IGF‐I) induced proliferation and immediate‐early‐gene expression of neonatal rat cardiac fibroblasts were investigated. Moreover the role of the IGF‐I receptor (IGF‐IR) in this process was evaluated.IGF‐I (10−9–10−7M) stimulated neonatal rat cardiac fibroblast growth in a dose‐dependent fashion (maximum: 3.5±0.1 fold, 10−7M), as determined by 5‐bromo‐2′‐deoxyuridine (BrdU) incorporation. ACE inhibition or AT1receptor blockade attenuated the IGF‐I (10−7M) induced neonatal rat cardiac fibroblast growth in a concentration‐dependent fashion (moexiprilat: 50±2%, enalaprilat: 31±2%, CV11974; 58±1%, all: 10−7M).IGF‐I stimulated cellular growth was accompanied by an upregulation of the immediate early genes c‐Fos (2.4±0.3 fold), Egr‐1 (4.7±1.1 fold) and Sp1 (6.2±0.7 fold). IGF‐I induced expression was completely inhibited by ACE inhibition or AT1receptor blockade.Stimulation with IGF‐I or Ang II (10−7M) increased IGF‐IR expression 5.7±0.5 fold and 3.6±0.5 fold respectively. The IGF‐I induced overexpression of the IGF‐IR was reduced by ACE inhibition with moexiprilat (10−7M) by 79±7% and by AT1receptor blockade with CV11974 (10−7M) by 79±5%.These data demonstrate that the mitogenic action of IGF‐I in neonatal rat cardiac fibroblasts is in part mediated by activation of the renin‐angiotensin system (RAS) with subsequent upregulation of IGF‐IR expression. This observation has important implications for the treatment of cardiac diseases with ACE inhibitors alone and their combination with IGF‐I or growth hormone.

1 The effects of angiotensin-converting enzyme (ACE) inhibition and angiotensin type 1 (AT1) receptor blockade on insulin-like growth factor-I (IGF-I) induced proliferation and immediate-early-gene expression of neonatal rat cardiac fibroblasts were investigated. Moreover the role of the IGF-I receptor (IGF-IR) in this process was evaluated. 2 IGF-I (10−9 – 10−7 M) stimulated neonatal rat cardiac fibroblast growth in a dose-dependent fashion (maximum: 3.5±0.1 fold, 10−7 M), as determined by 5-bromo-2′-deoxyuridine (BrdU) incorporation. ACE inhibition or AT1 receptor blockade attenuated the IGF-I (10−7 M) induced neonatal rat cardiac fibroblast growth in a concentration-dependent fashion (moexiprilat: 50±2%, enalaprilat: 31±2%, CV11974; 58±1%, all: 10−7 M). 3 IGF-I stimulated cellular growth was accompanied by an upregulation of the immediate early genes c-Fos (2.4±0.3 fold), Egr-1 (4.7±1.1 fold) and Sp1 (6.2±0.7 fold). IGF-I induced expression was completely inhibited by ACE inhibition or AT1 receptor blockade. 4 Stimulation with IGF-I or Ang II (10−7 M) increased IGF-IR expression 5.7±0.5 fold and 3.6±0.5 fold respectively. The IGF-I induced overexpression of the IGF-IR was reduced by ACE inhibition with moexiprilat (10−7 M) by 79±7% and by AT1 receptor blockade with CV11974 (10−7 M) by 79±5%. 5 These data demonstrate that the mitogenic action of IGF-I in neonatal rat cardiac fibroblasts is in part mediated by activation of the renin-angiotensin system (RAS) with subsequent upregulation of IGF-IR expression. This observation has important implications for the treatment of cardiac diseases with ACE inhibitors alone and their combination with IGF-I or growth hormone. British Journal of Pharmacology (2000) 131, 1592 – 1596

Estrogen and insulin-like-growth factor 1 (IGF-1) are potent mitogenic stimuli that share important properties in the control of cellular proliferation. However, the coupling between the signaling cascades of estrogen receptors α and β and the IGF-1 receptor (IGF-1R) is poorly understood. Therefore, we selectively transfected estrogen receptor α or β in COS7 and HEK293 cells, which contain IGF-1R. In presence of estrogen receptor α but not β, 17β-estradiol (E2) rapidly induces phosphorylation of the IGF-1R and the extracellular signal-regulated kinases 1/2. Furthermore, upon stimulation with E2, estrogen receptor α but not β bound rapidly to the IGF-1R in COS7 as well as L6 cells, which express all investigated receptors endogenously. Control experiments in the IGF-1R-deficient fibroblast cell line R−showed that after stimulation with E2 only estrogen receptor α bound to the transfected IGF-1R. Overexpression of dominant negative mitogen-activated protein kinases kinase inhibited this effect. Finally, estrogen receptor α but not β is required to induce the activation of the estrogen receptor-responsive reporter ERE-LUC in IGF-1-stimulated cells. Taken together, these data demonstrate that ligand bound estrogen receptor α is required for rapid activation of the IGF-1R signaling cascade.

The early growth response gene Egr-1 is a nuclear transcription factor known to serve as an intermediary in a broad range of signal transduction processes. Recent studies have assigned Egr-1 a new role as an amplifier of gene expression. Egr-1 mRNA is expressed in the myocardium and is rapidly induced in response to hypertrophic stimuli. However, induction of the Egr-1 protein has not yet been demonstrated in the myocardium; on the other hand, in skeletal muscle cells we have shown translational regulation of Egr-1. To further investigate the role of Egr-1 in the regulatory mechanisms of a variety of signal transduction processes we have therefore asked whether bona fide hypertrophic stimuli induce Egr-1 protein subsequently to its mRNA in neonatal rat cardiomyocytes or whether translational block occurs. In confocal laser studies the Egr-1 protein was nuclearly localized. Norepinephrine (NE, 2 μM), angiotensin II (AII, 0.1 μM), and endothelin 1 (E1, 0.1 μM) each induced the Egr-1 mRNA 6-8 fold and the Egr-1 protein 3-5 fold (n = 3, p < 0.01). Therefore, in contrast to skeletal muscle cells, these stimuli increased Egr-1 mRNA and protein levels. These results point further to the role of Egr-1 as a possible amplifier of signal transduction in the myocardium.

To determine the role of estrogen in skeletal muscle growth, we investigated estrogen receptor-mediated effects on proliferation in skeletal myoblasts. In L6, C2C12 and Sol8 myoblasts estrogen receptor was demonstrated by immunoblotting, immunofluorescence microscopy and transfection studies. Estrone induced a significant increase in myoblast growth whereas 17β-estradiol had no effect. Furthermore in L6-cells estrone (c-fos:3.9-fold,egr-1:4.6-fold) induced immediate–early gene induction significantly stronger than 17β-estradiol (c-fos:1.7-fold,egr-1:2.3-fold;p<0.05). Skeletal myoblasts express functional estrogen receptors. Estrogens differ in the activation of skeletal myoblast growth and immediate–early gene induction.

Gender‐based differences found in cardiovascular diseases raise the possibility that estrogen may have direct effects on cardiac tissue. Therefore we investigated whether cardiac myocytes and fibroblasts express functional estrogen receptors. Immunofluorescence demonstrated estrogen receptor protein expression in both female and male rat cardiac myocytes and fibroblasts. Nuclear translocation of the estrogen receptor protein was observed after stimulation of cardiomyocytes with 17β‐estradiol (E2). Cells transfected with an estrogen‐responsive reporter plasmid showed that treatment with E2induced a significant increase in reporter activity. Furthermore, E2induced a significant increase in expression of the estrogen receptors α and β, progesterone receptor and connexin 43 in cardiac myocytes. Cardiac myocytes and fibroblasts contain functional estrogen receptors and estrogen regulates expression of specific cardiac genes. These data suggest that gender‐based differences in cardiac diseases may in part be due to direct effects of estrogen on the heart.

The progression of left ventricular hypertrophy and cardiac fibrosis in hypertensive heart disease is influenced by sex and age. Although angiotensin converting enzyme inhibition has been shown to prevent progression of the disease in postmenopausal women, the interaction of angiotensin II and estrogen in this process before and after the menopause is poorly understood.

Objectives: NO production has been attributed to play a major role in cardiac diseases such as cardiac hypertrophy and cardiac remodeling after myocardial infarction which display significant gender-based differences. Therefore we assessed the effect of 17β-estradiol (E2) on estrogen receptor (ER) and β and endothelial and inducible NO synthase in neonatal and adult rat cardiomyocytes. Methods: The presence of ER and ERβ was demonstrated by immunofluorescence and western blot analysis as well as the expression pattern of inducible NO synthase (iNOS) and endothelial NOS (eNOS) in isolated cardiomyocytes from neonatal and adult rats. Furthermore, regulation of myocardial iNOS and eNOS expression by estrogen was evaluated in the myocardium from ovariectomized or sham-operated adult Wistar-Kyoto rats. Results: Incubation with E2 led to translocalization of the ER into the nucleus and increased receptor protein expression. E2 stimulated expression of iNOS and eNOS in both neonatal and adult cardiac myocytes. Coincubation with the pure anti-estrogen ICI 182.780 inhibited upregulation of ER and NOS expression. In ovariectomized rats myocardial iNOS and eNOS protein levels were significantly lower compared to sham-operated female animals. Conclusion: Taken together, these results show that E2 stimulates the expression of iNOS/eNOS in neonatal and adult cardiomyocytes in-vivo and in-vitro. These novel findings provide a potential mechanism of how estrogen may modulate NOS expression and NO formation in the myocardium.