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Florida Doulas' Perspectives on Their Role in Reducing Maternal Morbidity and Health Disparities. Womens Health Issues 2024:S1049-3867(24)00003-3. [PMID: 38503681 DOI: 10.1016/j.whi.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/06/2024] [Accepted: 01/18/2024] [Indexed: 03/21/2024]
Abstract
BACKGROUND Maternal mortality rates continue to rise in the United States. Considerable racial disparities exist, as Black women face two to three times the risks of dying from pregnancy-related complications compared with white women. Doulas have been associated with improved maternal outcomes. This study aimed to 1) investigate Florida doulas' perspectives and influence on severe maternal morbidity/mortality and related inequities, as well as 2) identify opportunities for actionable change. The social ecological model, which acknowledges how individual, interpersonal, institutional, community, and public policy factors intersect, informed our analysis. METHODS This qualitative study included seven online in-depth interviews and seven focus groups with doulas (N = 31) in Florida. Interview guides investigated how doulas perceive their role in the context of a) maternal morbidity and b) health disparities. RESULTS Doulas associated maternal morbidity and health disparities with Black pregnant people, identifying racism as a major contributor. Doulas identified their role as one that most often intersects with the individual and interpersonal levels of the social ecological model. Doulas report providing positive social surveillance and emotional support, contributing education and resources, and championing for advocacy in health care settings. Actionable steps recommended by doulas to further mitigate health disparities include the integration of implicit bias training into doula certification programs, increasing public health funding to bolster a doula workforce that can serve racial and ethnic communities, establishing doula-hospital partnerships to improve relational communication, providing tailored resources for clients featuring representative messaging, and doulas' continued engagement in positive social surveillance of their clients. CONCLUSIONS Doulas perceived their role as integral to mitigating maternal morbidity and health disparities, particularly in the context of supporting and advocating for birthing persons on all levels of the social ecological model. Equitable access to doulas for low-income and/or minoritized populations may be one key strategy to improve maternal health equity.
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Cancer-related information behavior among black and hispanics in an NCI-designated comprehensive cancer center catchment. PATIENT EDUCATION AND COUNSELING 2023; 114:107812. [PMID: 37257260 DOI: 10.1016/j.pec.2023.107812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 06/02/2023]
Abstract
OBJECTIVE This study aims to better understand health behaviors, particularly health information seeking, and how this impacts cancer care within underserved minority populations in a specific catchment area in Florida. METHODS We conducted an analysis of survey data from a 2019 community health survey conducted by the Moffit Cancer Center (MCC). We utilized the Comprehensive Model of Information Seeking (CMIS) as a framework and performed structural equation modeling (SEM) and related statistical analyses. RESULTS Our findings confirm that characteristics and demographics present a positive relationship to Online Health Information Seeking (OHIS). We also found that Utility had a negative significant relationship to OHIS. CONCLUSIONS We concluded that the CMIS is a useful framework for studying cancer-related information seeking, and that when properly executed in the confines of a study, can lend itself to in-depth statistical analyses as found in SEM. IMPLICATIONS The SEM revealed the CMIS to be promising with results in our analysis worthy of further investigation of cancer care and healthcare information access considering undeserved and minority populations. PRACTICE IMPLICATIONS Models such as the CMIS can be useful for understanding information seeking behaviors and to design information and communication interventions to improve access and health outcomes.
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Direct-to-Consumer Recruitment Methods via Traditional and Social Media to Aid in Research Accrual for Clinical Trials for Rare Diseases: Comparative Analysis Study. J Med Internet Res 2023; 25:e39262. [PMID: 36917158 PMCID: PMC10131902 DOI: 10.2196/39262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 01/20/2023] [Accepted: 01/27/2023] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Recruitment into clinical trials is a challenging process, with as many as 40% of studies failing to meet their target sample sizes. The principles of direct-to-consumer (DTC) advertising rely upon novel marketing strategies. The ability to reach expansive audiences in the web-based realm presents a unique opportunity for researchers to overcome various barriers to enrollment in clinical trials. Research has investigated the use of individual web-based platforms to aid in recruitment and accrual into trials; however, a gap in the literature exists, whereby multiple mass communication platforms have yet to be investigated across a range of clinical trials. OBJECTIVE There is a need to better understand how individual factors combine to collectively influence trial recruitment. We aimed to test whether DTC recruitment of potentially eligible study participants via social media platforms (eg, Facebook [Meta Platforms Inc] and Twitter [Twitter Inc]) was an effective strategy or whether this acted as an enhancement to traditional (eg, email via contact registries) recruitment strategies through established clinical research sites. METHODS This study tested multiple DTC web-based recruitment efforts (Facebook, Twitter, email, and patient advocacy group [PAG] involvement) across 6 national and international research studies from 5 rare disease consortia. Targeted social media messaging, social media management software, and individual study websites with prescreening questions were used in the Protocol for Increasing Accrual Using Social Media (PRISM). RESULTS In total, 1465 PRISM website referrals occurred across all 6 studies. Organic (unpaid) Facebook posts (676/1465, 46.14%) and Rare Diseases Clinical Research Network patient contact registry emails (461/1465, 31.47%) represented the most successful forms of engagement. PRISM was successful in accumulating a 40.1% (136/339) lead generation (those who screened positive and consented to share their contact information to be contacted by a clinical site coordinator). Despite the large number of leads generated from PRISM recruitment efforts, the number of patients who were subsequently enrolled in studies was low. Across 6 studies, 3 participants were ultimately enrolled, meaning that 97.8% (133/136) of leads dropped off. CONCLUSIONS The results indicate that although accrual results were low, this is consistent with previously documented challenges of studying populations with rare diseases. Targeted messaging integrated throughout the recruitment process (eg, referral, lead, and accrual) remains an area for further research. Key elements to consider include structuring the communicative workflow in such a way that PAG involvement is central to the process, with clinical site coordinators actively involved after an individual consents to share their contact information. Customized approaches are needed for each population and research study, with observational studies best suited for social media recruitment. As evidenced by lead generation, results suggest that web-based recruitment efforts, coupled with targeted messaging and PAG partnerships, have the potential to supplement clinical trial accrual.
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Information versus influence: An analysis of educational, relational, and identity rewards present in direct-to-consumer prescription drug advertising. J Am Pharm Assoc (2003) 2021; 61:795-803. [PMID: 34238672 DOI: 10.1016/j.japh.2021.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Pharmaceutical companies have rationalized rapid increases in spending on direct-to-consumer advertising (DTCA) by highlighting the educational potential that such efforts have for patients. Others have argued that profits and influence, not educational benefits, are the true motivators for the expansion of DTCA. It is critical that pharmacists be aware of the content of direct-to-consumer advertisements to best counsel patients on proper medication expectations. OBJECTIVES This study investigated the ways in which drug information is being presented to patients and whether such rewards may act as a form of education regarding a greater emphasis on the product or the condition the drug is designed to treat. METHODS This study conducted a content analysis of 60 broadcast prescription drug advertisements appearing over a 12-week primetime programming period across 4 major news networks to determine which types of educational, relational, and identity rewards were present across the textual, verbal, and visual modalities. RESULTS Findings indicated a greater overall presence of relational and identity rewards than educational rewards. Most of the educational rewards served to promote a particular drug rather than educate consumers about a condition. There was a statistically significant relationship between reward type and modality, such that there were greater relational and identity rewards within the visual modality and greater educational rewards in the textual modality than expected. CONCLUSION Findings showed that educational rewards in the service of promoting a particular drug were included more than 2.5 times as often as educational rewards about the condition treated. This lack of information about the condition suggests that DTCA may be aiming to increase profits by encouraging conversation between patients and providers about the advertised medications. As a result, a patient may demonstrate an increased desire to discuss a particular drug with a pharmacist or a provider rather than discussing information about the condition itself.
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A novel approach to conducting clinical trials in the community setting: utilizing patient-driven platforms and social media to drive web-based patient recruitment. BMC Med Res Methodol 2020; 20:58. [PMID: 32169041 PMCID: PMC7069058 DOI: 10.1186/s12874-020-00926-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/14/2020] [Indexed: 12/16/2022] Open
Abstract
Background Participant recruitment for clinical research studies remains a significant challenge for researchers. Novel approaches to recruitment are necessary to ensure that populations are easier to reach. In the context of rare diseases, social media provides a unique opportunity for connecting with patient groups that have representatively lower diagnosis rates when compared with more common diseases or illness. We describe the implementation of designing a patient-centered approach to message design for the purposes of recruiting patients for clinical research studies for rare disease populations. Methods Using an iterative research approach, we analyzed our previous experience of using web-based direct-to-patient recruitment methods to compare these online strategies with traditional center of excellence recruitment strategies. After choosing six research studies for inclusion in the previous study, in-depth, online interviews (n = 37) were conducted with patients represented in each disease category to develop and test recruitment message strategies for social media and a Web-based platform for patients to access study information and pre-screen. Finally, relationships were established with Patient Advocacy Groups representing each rare disease category to ensure further dissemination of recruitment materials via their own social media networks. Results Guided by social marketing theory, we created and tested various recruitment message designs. Three key message concepts preferred by patients emerged: (1) infographic; (2) positive emotional messages; and (3) educational information for sharing. A base study website was designed and created based on data from patient interviews. This website includes the option for potential participants to pre-screen and determine their eligibility for the study. Conclusions Study participants report wanting to be involved in the design and implementation of recruitment approaches for clinical research studies. The application of the aforementioned methods could aide in the evolution of clinical research practices for the recruitment of both rare and common diseases, where patient-centric approaches can help to create targeted messages designs that participants pre-test and support.
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The Use of Narratives to Deliver Information in Direct-To-Consumer Prescription Drug Commercials: A Content Analysis. JOURNAL OF HEALTH COMMUNICATION 2019; 24:512-524. [PMID: 31256712 DOI: 10.1080/10810730.2019.1631915] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Information communicated through a narrative format is typically processed and evaluated differently compared to non-narrative formats. Therefore, differences in the use of narratives across various information categories within direct-to-consumer prescription drug advertisements (DTCA) could have significant implications for consumers' processing of that information. Such differences could have further implications regarding the "fair balance" rule put forth by the Food and Drug Administration (FDA). This study sought to document the presence and nature of narrative and non-narrative messages in a content analysis of 61 U.S.-based broadcast DTCA airing during 2016. Specific narrative styles (classic drama, vignette, first person, second person, third person) were distinguished from non-narrative styles (lecture, directive, endorsement, graphic/demonstration) according to key characteristics of each (chronology and character, showing versus telling). Results indicated widespread use of narrative styles in DTCA overall, but the styles used differed substantially between different types of information. Narrative styles were delivered prominently to present health condition and drug benefits information while non-narrative styles primarily reinforced drug benefits and presented drug risks. These differences offer a new frame through which to view an imbalanced presentation of drug risks and benefits and provide a foundation for future research to test the effects of various narrative and non-narrative forms on patient understanding and message recall.
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The introduction of the medicinal partner in direct-to-consumer advertising: Viagra’s contribution to pharmaceutical fetishism and patient-as-consumer discourse in healthcare. QUALITATIVE RESEARCH IN MEDICINE & HEALTHCARE 2018. [DOI: 10.4081/qrmh.2018.7646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Pfizer, manufacturer of the erectile dysfunction prescription treatment Viagra, has been a staple in the pharmaceutical advertising arena since broadcast versions of such ads became legally permissible in the United States in 1997. Given that the patent for Viagra is soon set to expire, it is important that research take a look back in an attempt to contextualize the brand’s place in shaping medicinal marketing culture. Of particular interest is the period beginning in 2014, when Viagra’s most unconventional campaign yet began using a tactic that was the first of its kind for the pharmaceutical industry. By removing the actual consumer of the medication from these ads (males), Viagra has paved the way for pharmaceutical advertising to target the medicinal partner. This manuscript reviews the first use of the medicinal partner in the pharmaceutical advertising sector, conducting a textual analysis of Viagra’s use of this mediated relationship. The medicinal partner is the pharmaceutical industry’s attempt to target a patient’s social circle in an effort to promote a discourse that suggests a medicinal remedy for a problem. This analysis describes how social meaning and relationships underlie the market transaction of obtaining a prescription, as has been previously established through the processes of medicalization and pharmaceutical fetishism. These advertisements create belief in the larger sense, meaning Pfizer is infiltrating upon the patient’s process of choice and consumption of medicinal remedies. Viagra is simultaneously encouraging male consumers to celebrate the brand while using female ambassadors to influence the decision to request medicinal intervention.
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Abstract
Purpose The Patient-Centered Medical Home (PCMH) has become a dominant model of primary care re-design. This transformation presents a challenge to many care delivery organizations. The purpose of this paper is to describe attributes shaping successful and unsuccessful practice transformation within four medical practice groups. Design/methodology/approach As part of a larger study of 25 practices transitioning into a PCMH, the current study focused on diabetes care and identified high- and low-improvement medical practices in terms of quantitative patient measures of glycosylated hemoglobin and qualitative assessments of practice performance. A subset of the top two high-improvement and bottom two low-improvement practices were identified as comparison groups. Semi-structured interviews were conducted with diverse personnel at these practices to investigate their experiences with practice transformation and data were analyzed using analytic induction. Findings Results show a variety of key attributes facilitating more successful PCMH transformation, such as empanelment, shared goals and regular meetings, and a clear understanding of PCMH transformation purposes, goals, and benefits, providing care/case management services, and facilitating patient reminders. Several barriers also exist to successful transformation, such as low levels of resources to handle financial expense, lack of understanding PCMH transformation purposes, goals, and benefits, inadequate training and management of technology, and low team cohesion. Originality/value Few studies qualitatively compare and contrast high and low performing practices to illuminate the experience of practice transformation. These findings highlight the experience of organizational members and their challenges in practice transformation while providing quality diabetes care.
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An Updated Analysis of Direct-to-Consumer Television Advertisements for Prescription Drugs. Ann Fam Med 2018; 16:211-216. [PMID: 29760024 PMCID: PMC5951249 DOI: 10.1370/afm.2220] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/21/2017] [Accepted: 12/05/2017] [Indexed: 11/09/2022] Open
Abstract
PURPOSE In 2015, the American Medical Association called for a ban of direct-to-consumer advertising (DTCA) for prescription drugs. Yet, the pharmaceutical industry spends more than ever on broadcast advertisements, with national health care costs largely driven by drug spending. An evaluation of these ads is critical, as these advertisements can impact the frequency which patients ask their doctors about medications. METHODS A content analysis of prime-time direct-to-consumer ads was conducted across 4 major cable television networks. The ad content (n = 61) was coded for factual claims made regarding target conditions, appeals used, portrayal of medications, and lifestyle characteristics shown. RESULTS We found a substantial decrease in the percentage of ads that conveyed information about the conditions being targeted, such as risk factors (16%) and prevalence (16%). Positive emotional appeals (94%) continued to be emphasized; yet there was decreased use of negative emotional appeals (51%), pointing to an overall more positive portrayal of a patient's experience with a medication. The lifestyles portrayed in the sample largely featured how products can enable more recreational activities (69%) and fewer ads (7%) presented alternatives to product use. CONCLUSIONS Direct-to-consumer advertising continued to promote prescription drugs above educating the population. Improvement in the educational value of DTCA is likely to require regulatory action rather than reliance on self-regulation by the pharmaceutical industry.
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"In Principle We Have Agreement, But in Practice It Is a Bit More Difficult": Obtaining Organizational Buy-In to Patient-Centered Medical Home Transformation. QUALITATIVE HEALTH RESEARCH 2017; 27:909-922. [PMID: 27909251 DOI: 10.1177/1049732316680601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The patient-centered medical home (PCMH) is a model of care that emphasizes the coordination of patient treatment among health care providers. Practice transformation to this model, however, presents a number of challenges. One of these challenges is getting the buy-in of all personnel to commit to making organizational changes in the journey to becoming a nationally recognized medical home. This study investigated internal messages of buy-in as communicated by practices transitioning to this type of care. Grounding itself in stakeholder theory, this study analyzed interviews with staff, administration, and practitioners from 20 medical practices in a mid-Atlantic state. The analysis revealed three overarching themes: (a) communication among staff that is open, consistent; (b) implementation of reinforcement techniques; and (c) access to a change implementer who encourages successful evolution. Discussion of these themes provides recommendations for communication approaches to organizational buy-in for medical practices hoping to become a PCMH.
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Experimental and theoretical study of the structures and optical rotations of chiral bicyclic ortho esters. J Am Chem Soc 2002. [DOI: 10.1021/ja00221a008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Traceless cartesian tensor forms for spherical harmonic functions: new theorems and applications to electrostatics of dielectric media. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0305-4470/22/20/011] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
The dipole interaction model is used to investigate the effects of interactions between helices and supertwisting of helices by determining whether the predicted UV absorption and CD spectra for the three-helix bundle and coiled coil are significantly different from spectra for the single straight alpha-helix. Crystallographic data by Yan et al. for alpha-spectrin are used to construct a three-helix bundle of poly(L-alanine) modeling the protein. Backbone torsion angles represented by Fourier series are used to generate supertwisted helices and coiled coil models of poly(L-alanine) that have pitch, radius, and residue repeat similar to experimental crystallographic data on tropomyosin. Calculated CD spectra are compared with available experimental data. Theoretical spectra for the three-helix bundle and the supertwisted structures are quite similar to predictions for the straight alpha-helix of the same length with similar torsion angles, suggesting that CD is primarily dependent on the average backbone conformation and would not be a sensitive tool for distinguishing between single straight helices and closely packed or twisted alpha-helices.
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Effects of proline ring conformation on theoretical pi-pi* absorption and CD spectra of helical poly(L-proline) forms I and II. Biopolymers 1991; 31:529-35. [PMID: 1868168 DOI: 10.1002/bip.360310508] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Absorption and CD spectra of the pi-pi* transition near 200 nm are calculated for helical (Pro)10 forms I and II with a variable proline ring conformation characterized by torsion angle chi 2 in the range -60 degrees to 60 degrees. The spectra for poly(Pro) I are not sufficiently sensitive to chi 2 to suggest a preferred ring conformation. The spectra for poly(Pro) II are more sensitive to chi 2, and suggest preferred ring conformations near either or both of the chi 2 regions -50 +/- 10 degrees and 50 +/- 10 degrees.
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Bond-optimized ring closure for proline: comparison of conformations and semiempirical energies with small molecule X-ray structures. Biopolymers 1990; 30:437-50. [PMID: 2279073 DOI: 10.1002/bip.360300321] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A method is described for generating proline ring structures by successive addition of atoms, wherein ring closure is achieved by optimizing the fit to known ring bond-angles and one closing bond-length ("bond-optimized ring closure"). Two ring torsion angles are fixed independently within broad, allowed ranges, and the remaining torsion angles are determined uniquely in most cases. The independent torsion angles are chosen as phi and chi 2, and ring closure is achieved without prohibitive strain through most of the ranges -130 degrees less than phi less than -20 degrees and -60 degrees less than chi 2 less than 60 degrees. Comparisons of predicted ring structures to 191 X-ray diffraction structures from the literature, starting with the known values of phi and chi 2, yielded root-mean-square deviations of 4.8 degrees in chi 1, 4.7 degrees in chi 3, 8.3 degrees in chi 4, and 0.3-2% in the ring bond angles and the N-C delta distance. Semiempirical energies were calculated for the optimized structures using three sets of energy parameters from the literature. The energy surfaces show broad minima coinciding with the torsion angle regions in which the highest concentrations of observed structures are found. Two of the sets of energy parameters produce double minima corresponding to the "up" and "down" puckered conformations.
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Theoretical pi-pi absorption and circular dichroic spectra of beta-turn model peptides. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1986; 27:86-94. [PMID: 3949438 DOI: 10.1111/j.1399-3011.1986.tb02769.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The dipole interaction model, treated by the partially dispersive normal mode method, is used to calculate pi-pi absorption and circular dichroic spectra of beta-turn model peptides in certain conformations. These include Ac-Gly-Gly-NHMe, Ac-L-Ala-L-Ala-NHMe, and Ac-L-Ala-Gly-NHMe in the standard beta-turn conformations I, II, and III of Venkatachalam and cyclo(L-Ala-Gly-epsilon-aminocaproyl), cyclo(L-Ala-L-Ala-epsilon-aminocaproyl), and cyclo(L-Ala-D-Ala-epsilon-aminocaproyl) in the minimum-energy conformations of Nemethy et al. Boltzmann average circular dichroic spectra of the cyclic compounds agree with experimental spectra in most respects. The results are compared with previous theoretical CD spectra for these molecules and with conformational assignments based on other evidence. Absorption spectra in the pi-pi band are predicted to be moderately sensitive to conformation.
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Theoretical pi-pi* absorption and circular dichroic spectra of cyclic dipeptides. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1985; 26:518-27. [PMID: 4086166 DOI: 10.1111/j.1399-3011.1985.tb01019.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The dipole interaction model, treated by the partially dispersive normal mode method, is used to calculate circular dichroic spectra of cyclo(Gly-Gly), cyclo (Ala-Gly), cyclo(Ala-Ala), cyclo(Pro-Gly), cyclo(Pro-Ala), cyclo(Pro-Val), cyclo (Pro-D-Val), and cyclo(Pro-Pro) in the amide pi-pi* absorption band near 190 nm. Assuming a standard backbone geometry, spectra which are in fair to good agreement with experiment are obtained for these molecules. The spectra are predicted to be sensitive to conformations of Pro and Val side chains. The effects of dipeptide ring folding on calculated CD spectra are mostly consistent with those found by other workers, except that it is found that a planar ring conformation of cyclo (Ala-Ala) and cyclo (Ala-Gly) gives predicted spectra comparable to experiment. The same model gives theoretical absorption spectra consistent with available experimental data.
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Theoretical pi-pi absorption, circular dichroic, and linear dichroic spectra of collagen triple helices. Biopolymers 1984; 23:1891-904. [PMID: 6498285 DOI: 10.1002/bip.360231006] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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A demonstration of two-component behavior of the circular dichroic spectra of poly (L-tyrosine, 3-bromo-L-tyrosine) in trimethylphosphate. Biopolymers 1974; 13:1341-6. [PMID: 4411623 DOI: 10.1002/bip.1974.360130705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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The conformation of poly-beta-alanine in aqueous solution from proton magnetic resonance and deuterium exchange studies. J Am Chem Soc 1971; 93:3276-81. [PMID: 5571295 DOI: 10.1021/ja00742a030] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Comments on the one-dimensional Ising model and its application to the cis-trans equilibrium in poly-L-proline. Biopolymers 1968; 6:117-21. [PMID: 5641407 DOI: 10.1002/bip.1968.360060110] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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The conformation of poly-L-tyrosine in quinoline from dielectric dispersion studies. J Am Chem Soc 1966; 88:5419-29. [PMID: 5980173 DOI: 10.1021/ja00975a010] [Citation(s) in RCA: 50] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Poly-beta-L-aspartic acid. Synthesis through pentachlorophenyl active ester and conformational studies. J Am Chem Soc 1965; 87:119-20. [PMID: 5826971 DOI: 10.1021/ja01079a022] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Theory of the effects of concentration and chain length on helix-coil equilibria in two-stranded nucleic acids. J Chem Phys 1963; 39:2719-21. [PMID: 5878662 DOI: 10.1063/1.1734089] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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