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1.
J Manag Care Spec Pharm ; 23(6-a Suppl): S6-S12, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28535105

ABSTRACT

The debate around value in oncology drug selection has been prominent in recent years, and several professional bodies have furthered this debate by advocating for so-called value frameworks. Herein, we provide a viewpoint on these value frameworks, emphasizing the need to consider 4 key aspects: (1) the economic underpinnings of value; (2) the importance of the perspective adopted in the valuation; (3) the importance of the difference between absolute and relative measures of risk and measuring patient preferences; and (4) the recognition of multiple quality-of-life (QoL) domains, and the aggregation and valuation of those domains, through utilities within a multicriteria decision analysis, may allow prioritization of QoL above the tallying of safety events, particularly in a value framework focusing on the individual patient. While several frameworks exist, they incorporate different attributes and-importantly-assess value from alternative perspectives, including those of patients, regulators, payers, and society. The various perspectives necessarily lead to potentially different, if not sometimes divergent, conclusions about the valuation. We show that the perspective of the valuation affects the framing of the risk/benefit question and the methodology to measure the individual patient choice, or preference, as opposed to the collective, or population, choice. We focus specifically on the American Society of Clinical Oncology (ASCO) Value Framework. We argue that its laudable intent to assist in shared clinician-patient decision making can be augmented by more formally adopting methodology underpinned by micro- and health economic concepts, as well as application of formal quantitative approaches. Our recommendations for value frameworks focusing on the individual patient, such as the ASCO Value Framework, are 3-fold: (1) ensure that stakeholders understand the importance of the adopted (economic) perspective; (2) consider using exclusively absolute measures of risk and formal patient-preference methodology; and (3) consider foregoing safety parameters for higher-order utility considerations. DISCLOSURES: No funding was received for conceptualizing, writing, and/or editing this manuscript. Waldeck and White are employees of, and received stock option grants from, Celldex Therapeutics. Van Hout and Botteman are employees and shareholders of Pharmerit International. Pharmerit International is a research contractor for Celldex. All authors have retained editorial control of the content of the manuscript. Conceptualization of this viewpoint article was contributed primarily by Waldeck, along with Botteman, White, and van Hout. Data analysis and revision of the manuscript was contributed equally by all the authors. The manuscript was written by Waldeck, Botteman, van Hout, and White.


Subject(s)
Antineoplastic Agents/therapeutic use , Decision Making , Neoplasms/drug therapy , Antineoplastic Agents/economics , Humans , Insurance, Health, Reimbursement , Medical Oncology , Models, Economic , Neoplasms/economics , Patient Reported Outcome Measures , United States , Value-Based Purchasing
3.
Clin Orthop Relat Res ; 474(8): 1812-7, 2016 Aug.
Article in English | MEDLINE | ID: mdl-26797909

ABSTRACT

BACKGROUND: With the ubiquity of digital radiographs, the use of digital templating for arthroplasty has become commonplace. Although improved accuracy with digital radiographs and magnification markers is assumed, it has not been shown. QUESTIONS/PURPOSES: We wanted to (1) evaluate the accuracy of magnification markers in estimating the magnification of the true hip and (2) determine if the use of magnification markers improves on older techniques of assuming a magnification of 20% for all patients. METHODS: Between April 2013 and September 2013 we collected 100 AP pelvis radiographs of patients who had a THA prosthesis in situ and a magnification marker placed per the manufacturer's instructions. Radiographs seen during our standard radiographic review process, which met our inclusion criteria (AP pelvic view that included a well-positioned and observed magnification marker, and a prior total hip replacement with a known femoral head size), were included in the analysis. We then used OrthoView(TM) software program to calculate magnification of the radiograph using the magnification marker (measured magnification) and the femoral head of known size (true magnification). RESULTS: The mean true magnification using the femoral head was 21% (SD, 2%). The mean magnification using the marker was 15% (SD, 5%). The 95% CI for the mean difference between the two measurements was 6% to 7% (p < 0.001). The use of a magnification marker to estimate magnification at the level of the hip using standard radiographic techniques was shown in this study to routinely underestimate the magnification of the radiograph using an arthroplasty femoral head of known diameter as the reference. If we assume a magnification of 20%, this more closely approximated the true magnification routinely. With this assumption, we were within 2% magnification in 64 of the 100 hips and off by 4% or more in only four hips. In contrast, using the magnification marker we were within 2% of true magnification in only 20 hips and were off by 4% or more in 59 hips. CONCLUSION: We found the use of a magnification marker with digital radiographs for preoperative templating to be generally inaccurate, with a mean error of 6% and range from -5% to 15%. Additionally, these data suggest that the use of a magnification marker while taking preoperative radiographs of the hip may be unnecessary, as simply setting the software to assume a 20% magnification actually was more accurate. LEVEL OF EVIDENCE: Level III, diagnostic study.


Subject(s)
Arthrography/instrumentation , Femur Head/diagnostic imaging , Fiducial Markers , Hip Joint/diagnostic imaging , Radiographic Magnification/instrumentation , Anatomic Landmarks , Arthroplasty, Replacement, Hip , Femur Head/surgery , Hip Joint/surgery , Humans , Observer Variation , Predictive Value of Tests , Radiographic Image Interpretation, Computer-Assisted , Reproducibility of Results , Software
4.
Pain ; 157(2): 288-301, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26683233

ABSTRACT

This article summarizes the results of a meeting convened by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) on key considerations and best practices governing the design of acute pain clinical trials. We discuss the role of early phase clinical trials, including pharmacokinetic-pharmacodynamic (PK-PD) trials, and the value of including both placebo and active standards of comparison in acute pain trials. This article focuses on single-dose and short-duration trials with emphasis on the perioperative and study design factors that influence assay sensitivity. Recommendations are presented on assessment measures, study designs, and operational factors. Although most of the methodological advances have come from studies of postoperative pain after dental impaction, bunionectomy, and other surgeries, the design considerations discussed are applicable to many other acute pain studies conducted in different settings.


Subject(s)
Acute Pain/diet therapy , Analgesics/therapeutic use , Clinical Trials as Topic/methods , Pain Measurement/standards , Research Design , Clinical Trials as Topic/standards , Humans , Research Design/standards
5.
World J Cardiol ; 6(6): 367-75, 2014 Jun 26.
Article in English | MEDLINE | ID: mdl-24976908

ABSTRACT

Coronary heart disease (CHD) continues to be the greatest mortality risk factor in the developed world. Estrogens are recognized to have great therapeutic potential to treat CHD and other cardiovascular diseases; however, a significant array of potentially debilitating side effects continues to limit their use. Moreover, recent clinical trials have indicated that long-term postmenopausal estrogen therapy may actually be detrimental to cardiovascular health. An exciting new development is the finding that the more recently discovered G-protein-coupled estrogen receptor (GPER) is expressed in coronary arteries-both in coronary endothelium and in smooth muscle within the vascular wall. Accumulating evidence indicates that GPER activation dilates coronary arteries and can also inhibit the proliferation and migration of coronary smooth muscle cells. Thus, selective GPER activation has the potential to increase coronary blood flow and possibly limit the debilitating consequences of coronary atherosclerotic disease. This review will highlight what is currently known regarding the impact of GPER activation on coronary arteries and the potential signaling mechanisms stimulated by GPER agonists in these vessels. A thorough understanding of GPER function in coronary arteries may promote the development of new therapies that would help alleviate CHD, while limiting the potentially dangerous side effects of estrogen therapy.

6.
Gynecol Endocrinol ; 30(8): 553-6, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24884959

ABSTRACT

OBJECTIVE: To investigate cardiovascular risk factors in women with polycystic ovary syndrome (PCOS) combined with subclinical hypothyroidism (SCH). PATIENTS: A place-controlled study was performed. Group 1: 29 patients with PCOS and SCH; Group II: 35 patients with PCOS and normal thyroid function; and Group III: 34 healthy women with normal thyroid function. MAIN MEASURE INDEXES: Total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL), Carotid Arterial Intima-Media Thickness (CIMT), free triiodothyronine 3 (FT3), free triiodothyronine 4 (FT4), thyroid stimulating hormone (TSH), fasting glucose, 1-hour oral glucose tolerance test (OGTT1), 2-hour oral glucose tolerance test (OGTT2), fasting insulin, insulin after 1 hour oral glucose (INS1), insulin after 2 h oral glucose (INS2), HOM-IR = (fasting glucose × fasting insulin)/22.5. RESULTS: TG, TC FIN, INS1, and HOM-IR levels were significantly higher, but the mean HDL level was significantly lower in Group I than in Group II (p < 0.05). LDL cholesterol, FGOGTT1, OGTT2, and insulin after 2 h oral glucose were not significantly higher in Group I than in Group II (p > 0.05). TG, TC, FIN and INS contents 2 h meal, HOM-IR levels were significantly higher, and the mean HDL cholesterol level was significantly lower in Group I than in Group III (p < 0.05). Blood glucose levels after 1 and 2 h were not significantly higher in Group I than in the Group III (p > 0.05). Carotid Arterial Intima-Media Thickness (CIMT) was significantly thicker in Group I than other two groups. CONCLUSIONS: The PCOS patients combined with SCH have higher risk of cardiovascular risk factors than in controls or in patients with PCOS.


Subject(s)
Cardiovascular Diseases/etiology , Hypothyroidism/complications , Polycystic Ovary Syndrome/complications , Adult , Asymptomatic Diseases , Blood Pressure , Cardiovascular Diseases/diagnosis , Carotid Intima-Media Thickness , Case-Control Studies , Female , Glucose Tolerance Test , Humans , Hypothyroidism/blood , Hypothyroidism/diagnosis , Hypothyroidism/physiopathology , Lipids/blood , Polycystic Ovary Syndrome/blood , Polycystic Ovary Syndrome/diagnosis , Polycystic Ovary Syndrome/physiopathology , Risk Factors , Thyroid Hormones/blood , Thyrotropin/blood
7.
Pain ; 155(9): 1683-1695, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24865794

ABSTRACT

Proof-of-concept (POC) clinical trials play an important role in developing novel treatments and determining whether existing treatments may be efficacious in broader populations of patients. The goal of most POC trials is to determine whether a treatment is likely to be efficacious for a given indication and thus whether it is worth investing the financial resources and participant exposure necessary for a confirmatory trial of that intervention. A challenge in designing POC trials is obtaining sufficient information to make this important go/no-go decision in a cost-effective manner. An IMMPACT consensus meeting was convened to discuss design considerations for POC trials in analgesia, with a focus on maximizing power with limited resources and participants. We present general design aspects to consider including patient population, active comparators and placebos, study power, pharmacokinetic-pharmacodynamic relationships, and minimization of missing data. Efficiency of single-dose studies for treatments with rapid onset is discussed. The trade-off between parallel-group and crossover designs with respect to overall sample sizes, trial duration, and applicability is summarized. The advantages and disadvantages of more recent trial designs, including N-of-1 designs, enriched designs, adaptive designs, and sequential parallel comparison designs, are summarized, and recommendations for consideration are provided. More attention to identifying efficient yet powerful designs for POC clinical trials of chronic pain treatments may increase the percentage of truly efficacious pain treatments that are advanced to confirmatory trials while decreasing the percentage of ineffective treatments that continue to be evaluated rather than abandoned.


Subject(s)
Chronic Pain/therapy , Clinical Trials as Topic , Research Design , Chronic Pain/drug therapy , Humans , Sample Size
8.
Electrophoresis ; 35(14): 2008-13, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24668876

ABSTRACT

Mongolian is the eighth largest ethnic minority on Chinese population data according to the 2010 census. In the present study, we presented the first report about the allelic frequencies and forensic statistical parameters at the 21 new STRs and analyzed linkage disequilibrium of pairwise loci in the Mongolian ethnic minority, China. Hardy-Weinberg equilibrium tests demonstrated no significant deviations except for the D1S1627 locus. The cumulative power of discrimination and power of exclusion of all the loci are 0.9999999999999999992576 and 0.9999997528, respectively. The results of analysis of molecular variance showed that significant differences between the Mongolian and the other eight populations were found at 1-9 STR loci. In population genetics, the results of principal component analysis, structure analysis, and phylogenetic reconstruction analysis indicated shorter genetic distance between the Mongolian group and the Ningxia Han. All the results suggest that the 21 new STR loci will contribute to Chinese population genetics and forensic caseworks in the Mongolian group.


Subject(s)
Asian People/genetics , Ethnicity/genetics , Polymorphism, Genetic , China , Cluster Analysis , Gene Frequency , Humans , Linkage Disequilibrium , Microsatellite Repeats , Phylogeny , Principal Component Analysis
9.
J Arthroplasty ; 28(8 Suppl): 157-65, 2013 Sep.
Article in English | MEDLINE | ID: mdl-24034511

ABSTRACT

The Patient Protection and Affordable Care Act contains a number of provision for improving the delivery of healthcare in the United States, among the most impactful of which may be the call for modifications in the packaging of and payment for care that is bundled into episodes. The move away from fee for service payment models to payment for coordinated care delivered as comprehensive episodes is heralded as having great potential to enhance quality and reduce cost, thereby increasing the value of the care delivered. This effort builds on the prior experience around delivering care for arthroplasty under the Acute Care Episode Project and offers extensions and opportunities to modify the experience moving forward. Total hip and knee arthroplasties are viewed as ideal treatments to test the effectiveness of this payment model. Providers must learn the nuances of these modified care delivery concepts and evaluate whether their environment is conducive to success in this arena. This fundamental shift in payment for care offers both considerable risk and tremendous opportunity for physicians. Acquiring an understanding of the recent experience and the determinants of future success will best position orthopaedic surgeons to thrive in this new environment. Although this will remain a dynamic exercise for some time, early experience may enhance the chances for long term success, and physicians can rightfully lead the care delivery redesign process.


Subject(s)
Centers for Medicare and Medicaid Services, U.S./trends , Delivery of Health Care/trends , Patient Care Bundles/economics , Patient Protection and Affordable Care Act/trends , Quality of Health Care/economics , Reimbursement Mechanisms/trends , Arthroplasty, Replacement, Hip/economics , Arthroplasty, Replacement, Knee/economics , Centers for Medicare and Medicaid Services, U.S./economics , Delivery of Health Care/economics , Fee-for-Service Plans/economics , Health Care Costs/trends , Health Care Reform/economics , Humans , Orthopedics/economics , Patient Protection and Affordable Care Act/economics , Reimbursement Mechanisms/economics , Retrospective Studies , United States
10.
PLoS One ; 8(6): e64771, 2013.
Article in English | MEDLINE | ID: mdl-23840305

ABSTRACT

BACKGROUND: Vascular pathology and dysfunction are direct life-threatening outcomes resulting from atherosclerosis or vascular injury, which are primarily attributed to contractile smooth muscle cells (SMCs) dedifferentiation and proliferation by re-entering cell cycle. Increasing evidence suggests potent protective effects of G-protein coupled estrogen receptor 1 (GPER) activation against cardiovascular diseases. However, the mechanism underlying GPER function remains poorly understood, especially if it plays a potential role in modulating coronary artery smooth muscle cells (CASMCs). METHODOLOGY/PRINCIPAL FINDINGS: The objective of our study was to understand the functional role of GPER in CASMC proliferation and differentiation in coronary arteries using from humans and swine models. We found that the GPER agonist, G-1, inhibited both human and porcine CASMC proliferation in a concentration- (10(-8) to 10(-5) M) and time-dependent manner. Flow cytometry revealed that treatment with G-1 significantly decreased the proportion of S-phase and G2/M cells in the growing cell population, suggesting that G-1 inhibits cell proliferation by slowing progression of the cell cycle. Further, G-1-induced cell cycle retardation was associated with decreased expression of cyclin B, up-regulation of cyclin D1, and concomitant induction of p21, and partially mediated by suppressed ERK1/2 and Akt pathways. In addition, G-1 induces SMC differentiation evidenced by increased α-smooth muscle actin (α-actin) and smooth muscle protein 22α (SM22α) protein expressions and inhibits CASMC migration induced by growth medium. CONCLUSION: GPER activation inhibits CASMC proliferation by suppressing cell cycle progression via inhibition of ERK1/2 and Akt phosphorylation. GPER may constitute a novel mechanism to suppress intimal migration and/or synthetic phenotype of VSMC.


Subject(s)
Cell Differentiation/drug effects , Cell Proliferation/drug effects , Coronary Vessels/cytology , Cyclopentanes/pharmacology , Muscle, Smooth, Vascular/drug effects , Myocytes, Smooth Muscle/drug effects , Quinolines/pharmacology , Receptors, G-Protein-Coupled/agonists , Animals , Cells, Cultured , Coronary Vessels/drug effects , Coronary Vessels/physiology , Down-Regulation/drug effects , Humans , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/physiology , Myocytes, Smooth Muscle/physiology , Receptors, Estrogen , Swine , Up-Regulation/drug effects
11.
Pharmacol Res ; 71: 53-60, 2013 May.
Article in English | MEDLINE | ID: mdl-23466742

ABSTRACT

A key to harnessing the enormous therapeutic potential of estrogens is understanding the diversity of estrogen receptors and their signaling mechanisms. In addition to the classic nuclear estrogen receptors (i.e., ERα and ERß), over the past decade a novel G-protein-coupled estrogen receptor (GPER) has been discovered in cancer and other cell types. More recently, this non-genomic signaling mechanism has been found in blood vessels, and mediates vasodilatory responses to estrogen and estrogen-like agents; however, downstream signaling events involved acute estrogen action remain unclear. The purpose of this review is to discuss the latest knowledge concerning GPER modulation of cardiovascular function, with a particular emphasis upon how activation of this receptor could mediate acute estrogen effects in the heart and blood vessels (i.e., vascular tone, cell growth and differentiation, apoptosis, endothelial function, myocardial protection). Understanding the role of GPER in estrogen signaling may help resolve some of the controversies associated with estrogen and cardiovascular function. Moreover, a more thorough understanding of GPER function could also open significant opportunities for the development of new pharmacological strategies that would provide the cardiovascular benefits of estrogen while limiting the potentially dangerous side effects.


Subject(s)
Cardiovascular System/metabolism , Estrogens/metabolism , Receptors, Estrogen/metabolism , Receptors, G-Protein-Coupled/metabolism , Animals , Apoptosis , Cardiovascular Physiological Phenomena , Cardiovascular System/cytology , Cell Proliferation , Cyclic AMP/metabolism , Humans , MAP Kinase Signaling System , Muscle, Smooth/cytology , Muscle, Smooth/metabolism , Muscle, Smooth/physiology , Receptors, Estrogen/analysis , Receptors, G-Protein-Coupled/analysis
12.
J Pharmacol Exp Ther ; 345(1): 7-14, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23318471

ABSTRACT

Our knowledge of how androgens influence the cardiovascular system is far from complete, and this lack of understanding is especially true of how androgens affect resistance vessels. Our aim was to identify the signaling mechanisms stimulated by testosterone (TES) in microvascular arteries and to understand how these mechanisms mediate TES-induced vasodilation. Mesenteric microvessels were isolated from male Sprague-Dawley rats. Tension studies demonstrated a rapid, concentration-dependent, vasodilatory response to TES that did not involve protein synthesis or aromatization to 17ß-estradiol. Dichlorofluorescein fluorescence and nitrotyrosine immunoblot experiments indicated that TES stimulated peroxynitrite formation in microvessels, and functional studies demonstrated that TES-induced vasodilation was inhibited by scavenging peroxynitrite. As predicted, TES enhanced the production of both peroxynitrite precursors (i.e., superoxide and nitic oxide), and xanthine oxidase was identified as the likely source of TES-stimulated superoxide production. Functional and biochemical studies indicated that TES signaling involved activity of the phosphoinositide 3 (PI3) kinase-protein kinase B (Akt) cascade initiated by activation of the androgen receptor and culminated in enhanced production of cGMP and microvascular vasodilation. These findings, derived from a variety of analytical and functional approaches, provide evidence for a novel nongenomic signaling mechanism for androgen action in the microvasculature: TES-stimulated vasodilation mediated primarily by peroxynitrite formed from xanthine oxidase-generated superoxide and NO. This response was associated with activation of the PI3 kinase-Akt signaling cascade initiated by activation of the androgen receptor. We propose this mechanism could account for TES-stimulated cGMP production in microvessels and, ultimately, vasodilation.


Subject(s)
Androgens/pharmacology , Microvessels/drug effects , Peroxynitrous Acid/biosynthesis , Testosterone/pharmacology , Vascular Resistance/drug effects , Vasodilation/drug effects , Animals , Blotting, Western , Cyclic GMP/metabolism , Electron Spin Resonance Spectroscopy , In Vitro Techniques , Male , Microvessels/metabolism , Microvessels/physiopathology , Nitric Oxide/metabolism , Rats , Rats, Sprague-Dawley , Superoxides/metabolism , Xanthine Oxidase/metabolism
13.
Clin Orthop Relat Res ; 471(2): 537-43, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22948525

ABSTRACT

BACKGROUND: In 1984, we developed a private practice joint replacement registry (JRR) to prospectively follow patients undergoing THA and TKA to assess clinical and radiographic outcomes, complications, and implant survival. Little has been reported in the literature regarding management of this type of database, and it is unclear whether and how the information can be useful for addressing longer-term questions. QUESTIONS/PURPOSES: We answered the following questions: (1) What is the rate of followup for THA and TKA in our JRR? (2) What factors affect followup? (3) How successful is this JRR model in capturing data and what areas of improvement are identified? And (4) what costs are associated with maintaining this JRR? METHODS: We collected clinical data on all 12,047 patients having primary THA and TKA since 1984. Clinical and radiographic data were collected at routine followup intervals and entered into a prospective database. We searched this database to assess the rate of successful followup and data collection and to compare the effect of patient variables on followup. Costs related to database management were evaluated. RESULTS: Followup was poor at every time interval after surgery, with a tendency for worsening over time. Patients with a complication and those younger than 70 years tended to followup with greater frequency. There were difficulties with data capture and substantial expenses related to managing the database. CONCLUSIONS: Our findings highlight the difficulties in managing a JRR. Followup is poor and data collection is often incomplete. Newer technologies that allow easier tracking of patients and facilitate data capture may streamline this process and control costs.


Subject(s)
Arthroplasty, Replacement, Hip/statistics & numerical data , Arthroplasty, Replacement, Knee/statistics & numerical data , Hip Joint/surgery , Knee Joint/surgery , Adult , Age Factors , Aged , Aged, 80 and over , Databases, Factual , Female , Follow-Up Studies , Hip Joint/diagnostic imaging , Humans , Knee Joint/diagnostic imaging , Male , Middle Aged , Private Practice , Prospective Studies , Radiography , Registries , Reoperation , Risk Assessment , Treatment Outcome
14.
J Arthroplasty ; 28(1): 168-71, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22682040

ABSTRACT

Between February 1987 and October 2008, we performed 102 total hip arthroplasties (THAs) after failed internal fixation of a prior hip fracture. There were 39 intertrochanteric fractures and 63 femoral neck fractures. Etiology of failure included 35 cases of osteonecrosis, 32 cases of arthritis, 25 cases of early failure of fixation, and 10 cases of nonunion. There were 12 patients who had early surgical complications related to the procedure (11.8%, 12/102). These included 5 patients who had dislocations (4.9%), 4 periprosthetic fractures (3.9%), 2 hematomas (2.0%), and 1 infection (1%). Of these 102 THAs, 50 were available for at least 2 years of follow-up (mean, 3.2 years). At a minimum 2-year follow-up, THA after failed internal fixation of hip fracture in these patients was clinically successful with an elevated risk of periprosthetic fracture and dislocation.


Subject(s)
Arthroplasty, Replacement, Hip , Femoral Neck Fractures/surgery , Fracture Fixation, Internal , Hip Fractures/surgery , Adult , Aged , Aged, 80 and over , Arthritis/etiology , Female , Fractures, Ununited/surgery , Humans , Male , Middle Aged , Osteonecrosis/etiology , Reoperation , Treatment Failure
15.
Am J Physiol Heart Circ Physiol ; 302(1): H115-23, 2012 Jan 01.
Article in English | MEDLINE | ID: mdl-22081702

ABSTRACT

Androgens are reported to have both beneficial and detrimental effects on human cardiovascular health. The aim of this study was to characterize nongenomic signaling mechanisms in coronary artery smooth muscle (CASM) and define the ionic basis of testosterone (TES) action. TES-induced relaxation of endothelium-denuded porcine coronary arteries was nearly abolished by 20 nM iberiotoxin, a highly specific inhibitor of large-conductance, calcium-activated potassium (BK(Ca)) channels. Molecular patch-clamp studies confirmed that nanomolar concentrations of TES stimulated BK(Ca) channel activity by ∼100-fold and that inhibition of nitric oxide synthase (NOS) activity by N(G)-monomethyl-L-arginine nearly abolished this effect. Inhibition of nitric oxide (NO) synthesis or guanylyl cyclase activity also attenuated TES-induced coronary artery relaxation but did not alter relaxation due to 8-bromo-cGMP. Furthermore, we detected TES-stimulated NO production in porcine coronary arteries and in human CASM cells via stimulation of the type 1 neuronal NOS isoform. Inhibition of the cGMP-dependent protein kinase (PKG) attenuated TES-stimulated BK(Ca) channel activity, and direct assay determined that TES increased activity of PKG in a concentration-dependent fashion. Last, the stimulatory effect of TES on BK(Ca) channel activity was mimicked by addition of purified PKG to the cytoplasmic surface of a cell-free membrane patch from CASM myocytes (∼100-fold increase). These findings indicate that TES-induced relaxation of endothelium-denuded coronary arteries is mediated, at least in part, by enhanced NO production, leading to cGMP synthesis and PKG activation, which, in turn, opens BK(Ca) channels. These findings provide a molecular mechanism that could help explain why androgens have been reported to relax coronary arteries and relieve angina pectoris.


Subject(s)
Cyclic GMP-Dependent Protein Kinases/metabolism , Large-Conductance Calcium-Activated Potassium Channels/metabolism , Muscle, Smooth, Vascular/enzymology , Testosterone/metabolism , Vasodilation , Animals , Coronary Vessels/enzymology , Cyclic GMP-Dependent Protein Kinases/antagonists & inhibitors , Dose-Response Relationship, Drug , Enzyme Activation , Enzyme Inhibitors/pharmacology , Female , Guanylate Cyclase/antagonists & inhibitors , Guanylate Cyclase/metabolism , Large-Conductance Calcium-Activated Potassium Channels/antagonists & inhibitors , Male , Membrane Potentials , Muscle, Smooth, Vascular/drug effects , Nitric Oxide/metabolism , Nitric Oxide Synthase/antagonists & inhibitors , Nitric Oxide Synthase/metabolism , Patch-Clamp Techniques , Phosphorylation , Potassium Channels/pharmacology , Signal Transduction , Swine , Time Factors , Vasodilation/drug effects
16.
Am J Physiol Endocrinol Metab ; 301(5): E882-8, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21791623

ABSTRACT

Estrogens can either relax or contract arteries via rapid, nongenomic mechanisms involving classic estrogen receptors (ER). In addition to ERα and ERß, estrogen may also stimulate G protein-coupled estrogen receptor 1 (GPER) in nonvascular tissue; however, a potential role for GPER in coronary arteries is unclear. The purpose of this study was to determine how GPER activity influenced coronary artery reactivity. In vitro isometric force recordings were performed on endothelium-denuded porcine arteries. These studies were augmented by RT-PCR and single-cell patch-clamp experiments. RT-PCR and immunoblot studies confirmed expression of GPER mRNA and protein, respectively, in smooth muscle from either porcine or human coronary arteries. G-1, a selective GPER agonist, produced a concentration-dependent relaxation of endothelium-denuded porcine coronary arteries in vitro. This response was attenuated by G15, a GPER-selective antagonist, or by inhibiting large-conductance calcium-activated potassium (BK(Ca)) channels with iberiotoxin, but not by inhibiting NO signaling. Last, single-channel patch-clamp studies demonstrated that G-1 stimulates BK(Ca) channel activity in intact smooth muscle cells from either porcine or human coronary arteries but had no effect on channels isolated in excised membrane patches. In summary, GPER activation relaxes coronary artery smooth muscle by increasing potassium efflux via BK(Ca) channels and requires an intact cellular signaling mechanism. This novel action of estrogen-like compounds may help clarify some of the controversy surrounding the vascular effects of estrogens.


Subject(s)
Coronary Vessels/drug effects , Estradiol/pharmacology , Muscle Relaxation/drug effects , Muscle, Smooth, Vascular/drug effects , Receptors, G-Protein-Coupled/agonists , Animals , Calcium/metabolism , Cells, Cultured , Coronary Vessels/cytology , Coronary Vessels/physiology , Endothelium, Vascular/drug effects , Endothelium, Vascular/physiology , Humans , Large-Conductance Calcium-Activated Potassium Channels/metabolism , Large-Conductance Calcium-Activated Potassium Channels/physiology , Muscle Relaxation/physiology , Muscle, Smooth, Vascular/physiology , Myocytes, Smooth Muscle/drug effects , Myocytes, Smooth Muscle/metabolism , Nitric Oxide/metabolism , Receptors, Estrogen , Receptors, G-Protein-Coupled/metabolism , Swine , Up-Regulation/drug effects , Vasodilation/physiology
17.
Steroids ; 76(10-11): 991-7, 2011.
Article in English | MEDLINE | ID: mdl-21458475

ABSTRACT

Few studies have examined the potential effects of childbirth on the responses of the female vasculature--especially the resistance microvasculature of non-reproductive tissues. In the present study we have investigated the response of mesenteric microvascular resistance vessels to estrogen (E2), an important vasoactive hormone. Vessels were obtained from either nulliparous or postpartum female Sprague-Dawley rats, and isometric tension studies were performed. We found that E2 induced a concentration-dependent, endothelium-independent relaxation of microvessels precontracted with 10(-5) M phenylephrine; however, E2-induced relaxation was reduced by nearly half in vessels from postpartum animals compared to nulliparous controls. Inhibiting nitric oxide synthase activity with 10(-4) M L-NMMA or L-NPA (which exhibits selectivity for type 1 or nNOS) attenuated the relaxation effect of E2 on arteries from nulliparous animals. In contrast, L-NPA had little effect on arteries from postpartum animals, suggesting a reduced influence of nNOS after parturition. Moreover, expression of nNOS protein in microvessels was decreased 39% in the postpartum state compared to arteries from nulliparous animals. We propose that the impaired E2-induced relaxation response of microvessels from postpartum animals reflects a downregulation of NO production due to lower nNOS expressed in vascular smooth muscle cells. We measured a 73% decrease in serum E2 levels in the postpartum state compared to nulliparous animals. Because E2 has been shown to increase nNOS protein expression, we propose that lower E2 levels after parturition decrease expression of nNOS, leading to a reduced vasodilatory capacity of resistance microvessels.


Subject(s)
Estradiol/metabolism , Estradiol/pharmacology , Nitric Oxide Synthase Type I/metabolism , Vasodilation/drug effects , Animals , Blotting, Western , Enzyme-Linked Immunosorbent Assay , Female , In Vitro Techniques , Nitric Oxide/metabolism , Rats , Rats, Sprague-Dawley
18.
Invest Ophthalmol Vis Sci ; 52(8): 5515-24, 2011 Jul 25.
Article in English | MEDLINE | ID: mdl-21436276

ABSTRACT

PURPOSE: Elevated plasma homocysteine has been implicated in glaucoma, a vision disorder characterized by retinal ganglion cell death. The toxic potential of homocysteine to ganglion cells is known, but the mechanisms are not clear. A mechanism of homocysteine-induced death of cerebral neurons is via N-methyl-D-aspartate (NMDA) receptor overstimulation, leading to excess calcium influx and oxidative stress. This study examined the role of the NMDA receptor in homocysteine-mediated ganglion cell death. METHODS: Primary mouse ganglion cells were used for these experiments. NMDA receptor stimulation by homocysteine was determined by patch clamp analysis and fluorescent detection of intracellular calcium. NMDA receptor involvement in homocysteine-mediated cell death was determined through assessment of lactate dehydrogenase release and TUNEL analysis. These experiments used the NMDA receptor blocker MK-801. Induction of reactive species superoxide, nitric oxide, and peroxynitrite was measured by electron paramagnetic resonance spectroscopy, chemiluminescent nitric oxide detection, and immunoblotting for nitrotyrosine, respectively. RESULTS: 50 µM homocysteine stimulated the NMDA receptor in presence of 100 µM glycine. Homocysteine induced 59.67 ± 4.89% ganglion cell death that was reduced to 19.87 ± 3.03% with cotreatment of 250 nM MK-801. Homocysteine elevated intracellular calcium ∼7-fold, which was completely prevented by MK-801. Homocysteine treatment increased superoxide and nitric oxide levels by ∼40% and ∼90%, respectively, after 6 hours. Homocysteine treatment elevated peroxynitrite by ∼85% after 9 hours. CONCLUSIONS: These experiments provide compelling evidence that homocysteine induces retinal ganglion cell toxicity through direct NMDA receptor stimulation and implicate, for the first time, the induction of oxidative stress as a potent mechanism of homocysteine-mediated ganglion cell death.


Subject(s)
Apoptosis/drug effects , Homocystine/toxicity , Receptors, N-Methyl-D-Aspartate/metabolism , Retinal Ganglion Cells/pathology , Animals , Animals, Newborn , Calcium/metabolism , Dizocilpine Maleate/pharmacology , Electron Spin Resonance Spectroscopy , Excitatory Amino Acid Antagonists/pharmacology , In Situ Nick-End Labeling , L-Lactate Dehydrogenase/metabolism , Mice , Mice, Inbred C57BL , Nitric Oxide/metabolism , Oxidative Stress/drug effects , Patch-Clamp Techniques , Reactive Oxygen Species/metabolism , Receptors, AMPA/metabolism , Retinal Ganglion Cells/metabolism , Superoxides/metabolism
19.
Gynecol Endocrinol ; 27(4): 251-5, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21269226

ABSTRACT

Women with polycystic ovary syndrome (PCOS) exhibit a lower pregnancy rate, which may be related to decreased estrogen receptor (ER) expression or endometrial receptivity. We measured expression of ERα, ERß and the novel G protein-coupled ER (GPR30) in endometrium during window of implantation (WOI) in PCOS patients. Fifteen Chinese women with PCOS were compared to 15 normal subjects. Serial trans-vaginal ultrasonic scanner (TVUS) examinations detected follicular development, and endometrial thickness and pattern were assessed via TVUS on the day of ovulation. GPR30 expression was detected in the cytoplasm of endometrial epithelial cells, and was significantly lower in the PCOS group (p < 0.05). ERα and ERß expression was lower in the PCOS group, and was detected mainly in the nucleus of endometrial epithelial cells. There was no significant difference in endometrium thickness (p > 0.05), but there was a significant difference in the ultrasonic pattern (p < 0.05). Endometrial expression of GPR30, ERα and ERß was decreased during WOI in PCOS patients, and was accompanied by poor endometrial receptivity, low pregnancy rate and higher spontaneous abortions. We propose that restored receptor expression might improve endometrial receptivity and help lower infertility associated with PCOS.


Subject(s)
Endometrium/metabolism , Estrogen Receptor alpha/metabolism , Estrogen Receptor beta/metabolism , Polycystic Ovary Syndrome/metabolism , Receptors, G-Protein-Coupled/metabolism , Adult , Case-Control Studies , Embryo Implantation , Endometrium/diagnostic imaging , Endometrium/pathology , Estradiol/blood , Female , Humans , Ovulation , Pilot Projects , Polycystic Ovary Syndrome/diagnostic imaging , Polycystic Ovary Syndrome/pathology , Progesterone/blood , Receptors, Estrogen , Ultrasonography
20.
Clin Orthop Relat Res ; 469(2): 443-6, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21082363

ABSTRACT

BACKGROUND: Restoration of hip offset and leg length during THA is often limited by available implant geometries. The recent introduction of femoral components with a modular junction at the base of the neck (two modular junction components) has expanded the options to restore femoral offset and leg length. QUESTIONS/PURPOSES: We asked (1) whether a femoral component with two modular junctions would predict by templating more frequent restoration of preoperative offset and leg length abnormalities than one with single modular junctions; and (2) how our use of these options compared with national sales data. PATIENTS AND METHODS: We retrospectively reviewed the preoperative templating data in 100 primary THAs using single modular junction implants with only a neutral version stem and 100 THAs using two modular junction implants. We compared the frequency with which the desired leg length and offset were completely restored by preoperative templating in the two groups. RESULTS: Offset and leg lengths were restored to within 1 mm in 85% of cases with two modular junction implants and 60% of cases with single modular junction implants. An anteverted or a retroverted neck was used in 25% of cases with the two modular junction stems. The national sales data revealed femoral neck components with version were used in 28% of cases. CONCLUSIONS: The use of a femoral component with two modular junctions resulted in more frequent ability to restore femoral offset and leg length than a single modular junction. The advantage of clinical flexibility should be tempered by the potential concerns of prosthetic mechanical failure (which has been reported in another implant system with two modular junctions), increased third-body wear and corrosive debris, and increased prosthetic cost. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.


Subject(s)
Arthroplasty, Replacement, Hip/instrumentation , Hip Dislocation/rehabilitation , Hip Joint/surgery , Hip Prosthesis , Leg Length Inequality/rehabilitation , Femur/diagnostic imaging , Femur/surgery , Hip Dislocation/surgery , Hip Joint/anatomy & histology , Humans , Leg Length Inequality/surgery , Prosthesis Design , Radiography , Range of Motion, Articular , Retrospective Studies
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