1
|
Leistner DM, Laguna-Fernandez A, Haghikia A, Abdelwahed YS, Schatz AS, Erbay A, Roehle R, Fonseca AF, Ferber P, Landmesser U. Impact of elevated lipoprotein(a) on coronary artery disease phenotype and severity. Eur J Prev Cardiol 2024; 31:856-865. [PMID: 38348689 DOI: 10.1093/eurjpc/zwae007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 03/19/2024]
Abstract
AIMS A thorough characterization of the relationship between elevated lipoprotein(a) [Lp(a)] and coronary artery disease (CAD) is lacking. This study aimed to quantitatively assess the association of increasing Lp(a) levels and CAD severity in a real-world population. METHODS AND RESULTS This non-interventional, cross-sectional, LipidCardio study included patients aged ≥21 years undergoing angiography (October 2016-March 2018) at a tertiary cardiology centre, who have at least one Lp(a) measurement. The association between Lp(a) and CAD severity was determined by synergy between PCI with taxus and cardiac surgery (SYNTAX)-I and Gensini scores and angiographic characteristics. Overall, 975 patients (mean age: 69.5 years) were included; 70.1% were male, 97.5% had Caucasian ancestry, and 33.2% had a family history of premature atherosclerotic cardiovascular disease. Median baseline Lp(a) level was 19.3 nmol/L. Patients were stratified by baseline Lp(a): 72.9% had < 65 nmol/L, 21.0% had ≥100 nmol/L, 17.2% had ≥125 nmol/L, and 12.9% had ≥150 nmol/L. Compared with the normal (Lp(a) < 65 nmol/L) group, elevated Lp(a) groups (e.g. ≥ 150 nmol/L) had a higher proportion of patients with prior CAD (48.4% vs. 62.7%; P < 0.01), prior coronary revascularization (39.1% vs. 51.6%; P = 0.01), prior coronary artery bypass graft (6.0% vs. 15.1%; P < 0.01), vessel(s) with lesions (68.5% vs. 81.3%; P = 0.03), diffusely narrowed vessels (10.9% vs. 16.5%; P = 0.01) or chronic total occlusion lesions (14.3% vs. 25.2%; P < 0.01), and higher median SYNTAX-I (3.0 vs. 5.5; P = 0.01) and Gensini (10.0 vs. 16.0; P < 0.01) scores. CONCLUSION Elevated Lp(a) was associated with a more severe presentation of CAD. Awareness of Lp(a) levels in patients with CAD may have implications in their clinical management.
Collapse
Affiliation(s)
- David M Leistner
- Department of Cardiology, Campus Benjamin Franklin (CBF), Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
- Deutsches Zentrum für Herzkreislaufforschung (DZHK), partner site Berlin, DZHK-Geschäftsstelle, Potsdamer Str. 58, 10785 Berlin, Germany
- Friede Springer Cardiovascular Prevention Center, Charité, Hindenburgdamm 30, 12203 Berlin, Germany
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Straße 2, 10178 Berlin, Germany
- University Hospital Frankfurt and Wolfgang Goethe University, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
| | | | - Arash Haghikia
- Department of Cardiology, Campus Benjamin Franklin (CBF), Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
- Deutsches Zentrum für Herzkreislaufforschung (DZHK), partner site Berlin, DZHK-Geschäftsstelle, Potsdamer Str. 58, 10785 Berlin, Germany
- Friede Springer Cardiovascular Prevention Center, Charité, Hindenburgdamm 30, 12203 Berlin, Germany
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Straße 2, 10178 Berlin, Germany
| | - Youssef S Abdelwahed
- Department of Cardiology, Campus Benjamin Franklin (CBF), Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
- Deutsches Zentrum für Herzkreislaufforschung (DZHK), partner site Berlin, DZHK-Geschäftsstelle, Potsdamer Str. 58, 10785 Berlin, Germany
- Friede Springer Cardiovascular Prevention Center, Charité, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Anne-Sophie Schatz
- Department of Cardiology, Campus Benjamin Franklin (CBF), Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
- Deutsches Zentrum für Herzkreislaufforschung (DZHK), partner site Berlin, DZHK-Geschäftsstelle, Potsdamer Str. 58, 10785 Berlin, Germany
- Friede Springer Cardiovascular Prevention Center, Charité, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Aslihan Erbay
- Department of Cardiology, Campus Benjamin Franklin (CBF), Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
- Deutsches Zentrum für Herzkreislaufforschung (DZHK), partner site Berlin, DZHK-Geschäftsstelle, Potsdamer Str. 58, 10785 Berlin, Germany
- Friede Springer Cardiovascular Prevention Center, Charité, Hindenburgdamm 30, 12203 Berlin, Germany
- University Hospital Frankfurt and Wolfgang Goethe University, Theodor-Stern-Kai 7, 60596 Frankfurt, Germany
| | - Robert Roehle
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Straße 2, 10178 Berlin, Germany
- Institute of Biometry and Clinical Epidemiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ana F Fonseca
- Novartis Pharma AG, Fabrikstrasse 2, CH-4056 Basel, Switzerland
| | - Philippe Ferber
- Novartis Pharma AG, Fabrikstrasse 2, CH-4056 Basel, Switzerland
| | - Ulf Landmesser
- Department of Cardiology, Campus Benjamin Franklin (CBF), Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
- Deutsches Zentrum für Herzkreislaufforschung (DZHK), partner site Berlin, DZHK-Geschäftsstelle, Potsdamer Str. 58, 10785 Berlin, Germany
- Friede Springer Cardiovascular Prevention Center, Charité, Hindenburgdamm 30, 12203 Berlin, Germany
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Straße 2, 10178 Berlin, Germany
| |
Collapse
|
2
|
Fonseca AF, Byrne H, Laguna A, Itani T, Studer R, Heo J, Dillon A, Ferber P, Costa-Scharplatz M. Burden of lipoprotein(a) for patients with atherosclerotic cardiovascular disease: A retrospective analysis from the United States. J Manag Care Spec Pharm 2023; 29:519-529. [PMID: 37121256 PMCID: PMC10387958 DOI: 10.18553/jmcp.2023.29.5.519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
BACKGROUND: Lipoprotein(a) (Lp(a)) is an inherited, independent, and causal risk factor for atherosclerotic cardiovascular disease (ASCVD). OBJECTIVE: To assess the burden of elevated Lp(a) for patients with ASCVD in a real-world setting in the United States. METHODS: This retrospective cohort study assessed US patients with available Lp(a) measurement and established ASCVD using Optum's Clinformatics Data Mart database (2007-2020). Index date was defined as the first diagnosis of an ASCVD event. Patient demographics, medications, health care resource utilization (HCRU), and occurrence of cardiovascular events were assessed for patients with elevated (≥150 nmol/L) vs normal (≥65 nmol/L) Lp(a) levels, within the first year of index date. HCRU was characterized by inpatient hospitalization, inpatient length of stay (LOS), outpatient visits, and emergency department (ED) visits. All comparative analyses of patients with elevated (≥150 nmol/L) vs normal (≥65 nmol/L) Lp(a) levels within the first year of index date were adjusted for age, sex, baseline statin use, and diabetes. RESULTS: 8,372 patients with ASCVD and Lp(a) measurement in nmol/L were included in this study. Patient demographics and baseline clinical characteristics were similar among those with normal and elevated Lp(a). However, the proportion of patients receiving statins and β-blockers at baseline were significantly higher in the elevated vs normal Lp(a) group (54.76% vs 42.91%, P < 0.0001, and 30.92% vs 27.32%, P = 0.0183, respectively). At 1 year of follow-up, the rates per 100 person-years for ASCVD-related inpatient hospitalizations, outpatient hospitalizations, and ED visits were higher among patients with elevated Lp(a) compared with normal Lp(a) (13.33 vs 9.46, 89.08 vs 85.10, and 2.89 vs 2.29, respectively). The mean LOS per ASCVD-related hospitalization was 7.21 days in the elevated and 6.26 days in the normal Lp(a) group (P = 0.3462). During the 1-year post-index follow-up period, 15% of patients in the elevated Lp(a) group required revascularization compared with 10% of patients in the normal Lp(a) group (P = 0.0002). The odds of composite myocardial infarction, ischemic stroke, and revascularization occurrence of events within the first year of index was significantly higher in the elevated Lp(a) group compared with the normal Lp(a) group (1.46; 95% CI = 1.20-1.77; P < 0.05). CONCLUSIONS: HCRU within the first year of ASCVD diagnosis is substantial among patients with ASCVD and elevated Lp(a). Relatively higher rates of inpatient hospitalizations, increased LOS per hospitalization, and requirement of revascularization procedures within the first year of ASCVD index diagnosis were observed in patients with elevated Lp(a) compared with normal Lp(a) levels. Lp(a) testing in routine clinical practice could help in identification of high-risk patients with ASCVD and play an important role in the overall cardiovascular risk management, aiming to reduce the HCRU associated with ASCVD. DISCLOSURES: Ms Fonseca, Dr Laguna, Dr Itani, Dr Rachel Studer, and Dr Ferber are employees of Novartis Pharma AG, Basel, Switzerland. Ms Byrne is an employee of Novartis AG, Dublin, Ireland. Dr Costa-Scharplatz is an employee of Novartis Sweden AB, Stockholm, Sweden. Dr Heo and Ms Dillon are employees of Genesis Research. Genesis Research was commissioned to conduct the study (data extraction and analysis) on behalf of Novartis Pharma AG.
Collapse
|
3
|
Welsh P, Byrne H, Costa-Scharplatz M, Fonseca AF, Itani T, Farries G, Zabiby AA, Narasimham S, Martin L, Sattar N. The burden of coronary revascularization associated with lipoprotein(a) in patients with atherosclerotic cardiovascular disease: data from the UK Biobank. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.1529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background/Introduction
Elevated lipoprotein(a) [Lp(a)] is an inherited, independent, and causal risk factor for atherosclerotic cardiovascular disease (ASCVD). In a previous analysis of 30,510 ASCVD patients from UK Biobank, adjusted models showed a 100 nmol/L (≈50 mg/dL) difference in Lp(a) was associated with a 19% (95% CI 14–23%) higher risk of coronary revascularization (Welsh P, 2022).
Purpose
To determine the absolute risk for coronary revascularization in an ASCVD population with elevated versus normal Lp(a) levels.
Methods
This was an observational, retrospective study including 32,537 patients from UK Biobank with an ASCVD diagnosis (CHD, cerebrovascular or peripheral arterial disease). Absolute risk (AR) of coronary revascularization (number of coronary revascularizations per 100-person-years) was reported in patients with normal (<65 nmol/L ≈ 30 mg/dL; n=22,257) and elevated (≥150 nmol/L ≈ 70 mg/dL; n=5,204) Lp(a) levels across two time periods: within the first year of ASCVD diagnosis, and using all available follow-up data (median 4.7 years). Lp(a) was measured in an accredited single laboratory using a method standardized to WHO/IFCC reference material. The AR was also calculated for various subgroups within the ASCVD population.
Results
Within the first year after ASCVD diagnosis, 628 (12.07%) of the population with elevated Lp(a) underwent coronary revascularization compared to 1,787 (8.03%) with normal Lp(a). Those with elevated Lp(a) had a higher AR (14.00 per 100-person-years, 95% CI 13.02–14.99; p<0.001) than those with normal Lp(a) (9.34; 95% CI 8.92–9.76). This also held in a subgroup with myocardial infarction (MI; n=9,588), AR of 18.98 (95% CI 16.95–21.01) in those with elevated Lp(a) (n=1,571) vs. AR of 13.02 (95% CI 12.16–13.89) in those with normal Lp(a) (n=6,441) (p<0.001). AR of coronary revascularization within the first year of ASCVD diagnosis was also greater in participants with family history of CV disease (p<0.001) and premature CV disease (<60 years of age) (p<0.001). When using all available follow-up, AR of coronary revascularization was higher in participants with elevated versus normal Lp(a) in the ASCVD population (3.79 vs 2.55; p<0.001) and across all subgroups.
Conclusion
Elevated Lp(a) in patients with ASCVD was associated with increased risk of coronary revascularization in the first year (and subsequently), including those with a prior MI, premature CV disease, or family history of CV disease. Lp(a) testing in ASCVD patients can therefore aid estimations for the risk of revascularization, and thus the targeting of additional therapies to lower such risks.
Funding Acknowledgement
Type of funding sources: None.
Collapse
Affiliation(s)
- P Welsh
- Institute of Cardiovascular and Medical Sciences , Glasgow , United Kingdom
| | - H Byrne
- Novartis Pharma AG , Dublin , Ireland
| | | | | | - T Itani
- Novartis Pharma AG , Basel , Switzerland
| | - G Farries
- Novartis Pharma AG , Dublin , Ireland
| | | | | | - L Martin
- Novartis Pharmaceuticals UK Limited , London , United Kingdom
| | - N Sattar
- Institute of Cardiovascular and Medical Sciences , Glasgow , United Kingdom
| |
Collapse
|
4
|
Wachter R, Fonseca AF, Balas B, Kap E, Engelhard J, Schlienger R, Klebs S, Wirta SB, Kostev K. Real-world treatment patterns of sacubitril/valsartan: a longitudinal cohort study in Germany. Eur J Heart Fail 2019; 21:588-597. [PMID: 30972918 PMCID: PMC6607491 DOI: 10.1002/ejhf.1465] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/30/2019] [Accepted: 03/05/2019] [Indexed: 12/11/2022] Open
Abstract
AIMS To analyse real-world treatment patterns of sacubitril/valsartan (sac/val) using data from a pharmacy database in Germany. METHODS AND RESULTS A retrospective cohort study of 26 191 adult patients (aged ≥ 18 years) in the IMS® longitudinal prescriptions database in Germany who were dispensed sac/val from January 2016 to June 2017 was conducted. The analysis included sac/val dose titration assessed in the 6 months from first sac/val prescription; prescriptions of concomitant cardiovascular medications in the 6 months pre- and post-index and compliance and persistence during 12 months post-index. Two-thirds of patients were prescribed the lowest sac/val dose of 50 mg twice daily (b.i.d.) at index and up-titration during the first 6 months was attempted in 41% of these patients. Ten percent of patients prescribed 200 mg b.i.d. at index had to be stably down-titrated; among patients prescribed 50 or 100 mg b.i.d. at index that were up-titrated, > 80% remained on the higher dose. Overall, the mean daily diuretic dose decreased by 25% after initiation of sac/val. High compliance and persistence rates were observed across sac/val doses, increasing with higher sac/val dose at index. Prior dose of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker had only minor impact on first sac/val dose, compliance and persistence. CONCLUSIONS Most patients prescribed sac/val are not initiated on the recommended dose nor up-titrated as recommended by the EU Summary of Product Characteristics. Initiation of sac/val was associated with high persistence and compliance and a dose reduction of diuretics. Barriers to up-titration must be explored.
Collapse
Affiliation(s)
- Rolf Wachter
- Clinic and Polyclinic for Cardiology, University Hospital Leipzig, Leipzig, Germany.,German Cardiovascular Research Center, Partner Site Göttingen, Göttingen, Germany
| | | | - Bogdan Balas
- Novartis Pharma AG, Basel, Switzerland.,F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Elisabeth Kap
- IQVIA Germany (IQVIA Commercial GmbH & Co. OHG), Frankfurt, Germany
| | | | | | - Sven Klebs
- Novartis Pharma GmbH, Nuremberg, Germany
| | | | - Karel Kostev
- IQVIA Germany (IQVIA Commercial GmbH & Co. OHG), Frankfurt, Germany
| |
Collapse
|
5
|
Wachter R, Balas B, Klebs S, Kap E, Engelhard J, Fonseca AF, Schlienger R, Dworak M, Bruce Wirta S. P907Titration patterns and clinical characteristics of patients prescribed sacubitril/valsartan in the primary care and cardiology settings in Germany. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.p907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- R Wachter
- Universitätsklinikum Leipzig, Leipzig, Germany
| | - B Balas
- Novartis Pharma AG, Basel, Switzerland
| | - S Klebs
- Novartis Pharma GmbH, Nuremberg, Germany
| | - E Kap
- IQVIA Germany (IQVIA Commercial GmbH & Co. OHG), Frankfurt, Germany
| | - J Engelhard
- IQVIA Germany (IQVIA Commercial GmbH & Co. OHG), Frankfurt, Germany
| | | | | | - M Dworak
- Novartis Pharma GmbH, Nuremberg, Germany
| | | |
Collapse
|
6
|
Coluci VR, Fonseca AF, Galvão DS, Daraio C. Entanglement and the nonlinear elastic behavior of forests of coiled carbon nanotubes. Phys Rev Lett 2008; 100:086807. [PMID: 18352653 DOI: 10.1103/physrevlett.100.086807] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Indexed: 05/26/2023]
Abstract
Helical or coiled nanostructures have been objects of intense experimental and theoretical studies due to their special electronic and mechanical properties. Recently, it was experimentally reported that the dynamical response of a foamlike forest of coiled carbon nanotubes under mechanical impact exhibits a nonlinear, non-Hertzian behavior, with no trace of plastic deformation. The physical origin of this unusual behavior is not yet fully understood. In this Letter, based on analytical models, we show that the entanglement among neighboring coils in the superior part of the forest surface must be taken into account for a full description of the strongly nonlinear behavior of the impact response of a drop ball onto a forest of coiled carbon nanotubes.
Collapse
Affiliation(s)
- V R Coluci
- Instituto de Física "Gleb Wataghin," Universidade Estadual de Campinas, C.P. 6165, 13083-970 Campinas SP, Brazil.
| | | | | | | |
Collapse
|
7
|
Fonseca AP, Extremina C, Fonseca AF, Sousa JC. Effect of subinhibitory concentration of piperacillin/tazobactam on Pseudomonas aeruginosa. J Med Microbiol 2004; 53:903-910. [PMID: 15314198 DOI: 10.1099/jmm.0.45637-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Subinhibitory concentrations (sub-MICs) of antibiotics, although not able to kill bacteria, can modify their physico-chemical characteristics and the architecture of their outermost surface and may interfere with some bacterial functions. This study investigated the ability of sub-MIC piperacillin/tazobactam (P/T) to interfere with the bacterial virulence parameters of adhesiveness, cell-surface hydrophobicity, motility, biofilm formation and sensitivity to oxidative stress. Antimicrobial activity against five Pseudomonas aeruginosa clinical isolates, representative of clonal lineages of 96 strains of nosocomial origin, and six control strains (ATCC 27853, PAO1, AK1, MT1562, PT623, PAO1algC) was evaluated in vitro using the NCCLS microdilution method. The effects of sub-MIC on bacterial adhesion and biofilm formation were studied using a modified microtitre plate assay. The relative cell-surface hydrophobicity of P. aeruginosa strains was determined by measuring their ability to adhere to n-hexadecane. P. aeruginosa that had been exposed overnight to P/T and incubated with P/T in the plate were also screened for their ability to swim using flagella and to twitch and for their sensitivity to oxidative stress. The results obtained showed that the impact of sub-MIC P/T on bacterial characteristics was different for the various strains of P. aeruginosa. There was a change in bacterial morphology and hydrophobicity that could explain a significant decrease in adhesion values in all clinical isolates and controls tested, a decrease in biofilm formation, a significant increase in sensitivity to oxidative stress, a significant decrease in flagellum-mediated swimming and a decrease in type IV fimbriae-mediated twitching. The results obtained indicate that sub-MIC P/T interferes with the pathogenic potential of P. aeruginosa.
Collapse
Affiliation(s)
- A P Fonseca
- Department of Microbiology, Faculty of Medicine, University of Porto, Portugal 2IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Portugal 3Department of Microbiology, Faculty of Pharmacy, University of Porto, Portugal
| | - C Extremina
- Department of Microbiology, Faculty of Medicine, University of Porto, Portugal 2IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Portugal 3Department of Microbiology, Faculty of Pharmacy, University of Porto, Portugal
| | - A F Fonseca
- Department of Microbiology, Faculty of Medicine, University of Porto, Portugal 2IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Portugal 3Department of Microbiology, Faculty of Pharmacy, University of Porto, Portugal
| | - J C Sousa
- Department of Microbiology, Faculty of Medicine, University of Porto, Portugal 2IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Portugal 3Department of Microbiology, Faculty of Pharmacy, University of Porto, Portugal
| |
Collapse
|
8
|
Fonseca AF, de Aguiar MA. Near equilibrium dynamics of nonhomogeneous Kirchhoff filaments in viscous media. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 63:016611. [PMID: 11304382 DOI: 10.1103/physreve.63.016611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2000] [Revised: 08/11/2000] [Indexed: 05/23/2023]
Abstract
We study the near equilibrium dynamics of nonhomogeneous elastic filaments in viscous media using the Kirchhoff model of rods. Viscosity is incorporated in the model as an external force, which we approximate by the resistance felt by an infinite cylinder immersed in a slowly moving fluid. We use the recently developed method of Goriely and Tabor [Phys. Rev. Lett. 77, 3537 (1996); Physica D 105, 20 (1997); 105, 45 (1997)] to study the dynamics in the vicinity of the simplest equilibrium solution for a closed rod with nonhomogeneous distribution of mass, namely, the planar ring configuration. We show that small variations of the mass density along the rod are sufficient to couple the symmetric modes of the homogeneous rod problem, producing asymmetric deformations that modify substantially the dynamical coiling, even at quite low Reynolds number. The higher-density segments of the rod tend to become more rigid and less coiled. We comment on possible applications to DNA.
Collapse
Affiliation(s)
- A F Fonseca
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Unicamp 13083-970, Campinas, SP, Brazil
| | | |
Collapse
|
9
|
Pina-Vaz C, Rodrigues AG, Sansonetty F, Martinez-De-Oliveira J, Fonseca AF, Mårdh PA. Antifungal activity of local anesthetics against Candida species. Infect Dis Obstet Gynecol 2000; 8:124-37. [PMID: 10968594 PMCID: PMC1784683 DOI: 10.1155/s1064744900000168] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE To evaluate the activity of benzydamine, lidocaine, and bupivacaine, three drugs with local anesthetic activity, against Candida albicans and non-albicans strains and to clarify their mechanism of activity. METHODS The minimal inhibitory concentration (MIC) was determined for 20 Candida strains (18 clinical isolates and two American Type Culture Collection strains). The fungistatic activity was studied with the fluorescent probe FUN-1 and observation under epifluorescence microscopy and flow cytometry. The fungicidal activity of the three drugs was assayed by viability counts. Membrane alterations induced in the yeast cells were evaluated by staining with propidium iodide, by quantitation of intracellular K+ leakage and by transmission electron microscopy of intact yeast cells and prepared spheroplasts. RESULTS The MIC ranged from 12.5-50.0 microg/mL, 5.0-40.0 mg/mL, and 2.5-10.0 mg/mL for benzydamine, lidocaine, and bupivacaine, respectively. The inhibitory activity of these concentrations could be detected with the fluorescent probe FUN-1 after incubation for 60 minutes. A very fast fungicidal activity was shown by 0.2, 50, and 30 mg/mL of benzydamine, lidocaine, and bupivacaine, respectively. CONCLUSIONS At lower concentrations, the tested drugs have a fungistatic activity, due to yeast metabolic impairment, while at higher concentrations they are fungicidal, due to direct damage to the cytoplasmic membrane.
Collapse
Affiliation(s)
- C Pina-Vaz
- Department of Microbiology, Porto School of Medicine, University of Porto, Portugal.
| | | | | | | | | | | |
Collapse
|
10
|
Abstract
Hydrophobic interaction is generally considered to play an important role in the adherence of microorganisms to eukaryotic cells and also to certain inert surfaces. Using a microbe adhesion assay to hydrocarbons (n-hexadecane), 68 strains of Candida albicans and 30 non-albicans strains were studied. Influence of source of isolate, age of the culture, and percentage of germ tube formation on adhesion were studied. C. albicans blastoconidia were found to be hydrophilic; conversely, blastoconidia of non-albicans strains were slightly more hydrophobic. Germ tube formation was associated with a significant rise in cell surface hydrophobicity.
Collapse
Affiliation(s)
- A G Rodrigues
- Department of Microbiology, Porto School of Medicine, University of Porto, Portugal.
| | | | | | | | | |
Collapse
|
11
|
Rodrigues AG, Mårdh PA, Pina-Vaz C, Martinez-de-Oliveira J, Fonseca AF. Germ tube formation changes surface hydrophobicity of Candida cells. Infect Dis Obstet Gynecol 1999; 7. [PMID: 10524666 PMCID: PMC1784750 DOI: 10.1002/(sici)1098-0997(1999)7:5<222::aid-idog3>3.0.co;2-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hydrophobic interaction is generally considered to play an important role in the adherence of microorganisms to eukaryotic cells and also to certain inert surfaces. Using a microbe adhesion assay to hydrocarbons (n-hexadecane), 68 strains of Candida albicans and 30 non-albicans strains were studied. Influence of source of isolate, age of the culture, and percentage of germ tube formation on adhesion were studied. C. albicans blastoconidia were found to be hydrophilic; conversely, blastoconidia of non-albicans strains were slightly more hydrophobic. Germ tube formation was associated with a significant rise in cell surface hydrophobicity.
Collapse
Affiliation(s)
- A G Rodrigues
- Department of Microbiology, Porto School of Medicine, University of Porto, Portugal.
| | | | | | | | | |
Collapse
|
12
|
de Oliveira JM, Cruz AS, Fonseca AF, Vaz CP, Rodrigues A, Aurea F, Maia J, Sousa JA. Prevalence of Candida albicans in vaginal fluid of asymptomatic Portuguese women. J Reprod Med 1993; 38:41-2. [PMID: 8441130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Candida albicans is by far the most frequent agent of genital candidosis. We studied the prevalence of C albicans in normal asymptomatic women attending primary health care centers throughout Portugal. The overall prevalence of C albicans in the vaginal fluid of 1,004 women studied was 10.4%. Interestingly, the prevalence rates were lower (6.8%) in women taking combination oral contraceptives and higher (13.0%) in those using intrauterine devices.
Collapse
Affiliation(s)
- J M de Oliveira
- Portuguese Group for the Study of Pelvic Inflammatory Disease and Sexually Transmitted Diseases, University of Porto School of Medicine
| | | | | | | | | | | | | | | |
Collapse
|