Perinatal Depression Educational Training for Graduate Nursing Students

The purpose of this study was to implement and assess an educational intervention for nursing students pertaining to perinatal depression (PD) screening and treatment. A single group (n = 59), repeated-measures design (i.e., pre- and post-intervention assessments) was used to assess the impact of an online intervention. Demographics, Theory of Planned Behavior constructs, intention to screen and treat PD, and PD-related knowledge were tested. The intervention resulted in positive gains in PD-related perceived behavioral control (PBC), attitudes, subjective norms, knowledge, intention to screen and treat PD, and perceived importance of screening and treating PD from pre- to post-intervention. PBC demonstrated a small-to-moderate positive association with perceived importance of screening and treating PD at post-intervention. Results from the current study suggest that the PD online educational intervention is effective in improving participants' PD-related PBC, attitudes, subjective norms, knowledge, and intention to screen and treat PD.

Suicide Exposure in Crisis Workers

Background: Crisis workers provide services to individuals who are in acute distress. There is no research examining personal and occupational exposure to suicide in these workers. Aims: We aimed to examine the prevalence of personal, occupational, and colleague suicide exposure among crisis workers, the mental health outcomes associated with suicide exposures, and perceived professional preparedness for client suicide. Method: Crisis workers (n = 115) completed an online survey assessing suicide exposure, depression, anxiety, and posttraumatic stress disorder. Results: Over a third of participants (33.9%, n = 37) reported that they had lost at least one client to suicide, with an average of 2.30 clients (SD = 4.47) lost to suicide. Over three quarters (77.1%, n = 81) of study participants reported they had experienced at least one personal loss to suicide. Those who perceived their relationship to the personal suicide as close or very close had significantly greater PTSD symptoms (M = 3.29, SD = 2.23) than those who perceived their relationship as not at all close, not close, or somewhat close (M = 1.38, SD = 1.69), t(20) = -2.10, p = .049. Limitations: Snowball sampling is the study's main limitation. Conclusion: The current study demonstrates that a substantial percentage of crisis workers are exposed to suicide and additional research is needed to determine how exposures impact practice and personal symptoms in this population.

Perinatal depression screening rates, correlates, and treatment recommendations in an obstetric population

INTRODUCTION

The current study aimed to assess perinatal depression (PD) screening and treatment practices of obstetrical health care providers.

METHOD

Retrospective record reviews (n = 557) evaluated the PD screening, referral, and treatment practices at an Obstetrician/Gynecology practice. This study assessed the frequency of screening for PD, rates of elevated Edinburgh Postnatal Depression Scale (EPDS) scores, treatment recommendations, demographic correlates, and predictors of elevated EPDS scores.

RESULTS

PD screening completion rates were: 60.1% (intake), 35% (glucola test), and 85.5% (6-week follow-up). Rates of clinically elevated EPDS scores were: 18.21% (intake), 17.43% (glucola test), and 13.00% (6-week follow-up). Correlates of clinically elevated EPDS scores at intake and 6-week follow-up were history of depression, history of anxiety, and young age. History of depression and anxiety were associated with an increased likelihood of having a clinically significant EPDS score at intake. Intake EPDS score and history of depression were associated with an increased likelihood of having a clinically significant EPDS score at 6-week follow-up.

DISCUSSION

Obstetric/gynecology providers should screen for perinatal depression at every obstetrical appointment. It is important to thoroughly assess history of depression and anxiety. Education and training for health care providers and perinatal women may improve the mental health experience of perinatal women. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Psychometric assessment of the Edinburgh Postnatal Depression Scale in an obstetric population

The prevalence and negative effects of perinatal depression are well known. The Edinburgh Postnatal Depression Scale (EPDS) is a common screening tool for perinatal depression and it is recommended for use by several professional organizations. The current study tested competing EPDS factor structures and assessed EPDS change from intake to 6-week follow-up, and identified demographic correlates in an outpatient obstetric sample. Using a retrospective observational study design, medical records were coded for demographic, mental health, and EPDS patient data (n = 524). Confirmatory factor analysis, t-tests, and ANOVA were utilized. Findings included: (1) a 3-factor model (i.e. anxiety, depression, anhedonia) of the EPDS displayed the best fit to the current data; (2) small declines in all 3 subscales of the EPDS from intake to 6-week follow-up appointments and; (3) demographic correlates of EPDS subscales included history of depression, history of anxiety, race, and pregnancy status (i.e. first child or not). The 3-factor structure can be used in clinical practice to assess perinatal depression in a nuanced fashion. Given that history of depression and anxiety are risk factors for perinatal depression, a thorough assessment of these items in clinical practice is needed.

Risk and protective factors of dementia among adults with post-traumatic stress disorder: a systematic review protocol

INTRODUCTION

Post-traumatic stress disorder (PTSD) is associated with an increased risk of dementia. Individual epidemiological studies have controlled for several confounders of the relationship between PTSD and increased dementia risk, yet particular risk factors underlying this relationship have not been determined. This systematic review protocol aims to identify risk and protective factors of dementia among adults with PTSD.

METHODS AND ANALYSIS

We will conduct an electronic search of the databases: PubMed, CINAHL, PsychINFO, The Cochrane Library, Scopus and ProQuest Dissertation and Theses Global. After screening the studies, quantitative synthesis will be performed, if possible. Otherwise, a narrative synthesis will be performed. We will include randomised controlled trials and other types of research evidence including longitudinal cohort studies. Strength of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations method. Examples of variables that will be extracted are: year of PTSD diagnosis, comorbid conditions, health behaviours, pharmacological treatments and year of mild cognitive impairment or dementia diagnosis. We developed this systematic review protocol according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 statement.

ETHICS AND DISSEMINATION

The proposed study will not collect individual-level data and, therefore, does not require ethical approval. Results of this study will provide current evidence on risk and protective factors of dementia in adults with PTSD. Findings will be disseminated in peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42019128553.

Initial Validation of the Suicide Competency Assessment Form among Behavioral Health Staff in the National Health Services Trust

The Suicide Competency Assessment Form (SCAF) provides a framework for suicide prevention skills training. This study assessed SCAF psychometric properties in a sample of behavioral health staff. A cross-sectional survey of National Health Services (NHS) staff from varying disciplines (N = 170) was conducted. The SCAF yielded a 1-factor structure with high internal consistency. Nursing assistants reported lower SCAF scores compared to other professionals. SCAF scores demonstrated positive associations with prior suicide prevention training, job enthusiasm, and several suicide/self-injury prevention outcome expectations (i.e., optimism working with self-harming patients and perceived ability to help self-harming patients). SCAF scores further demonstrated incremental validity in the form of multivariate model associations with suicide/self-injury prevention outcome expectations. Improved job satisfaction mediated the pathway from SCAF scores to perceived ability to help self-harming patients. The SCAF can be utilized in suicide prevention training and clinical supervision.

The Brief COPE: Factor Structure and Associations With Self- and Other-Directed Aggression Among Emerging Adults

The Brief COPE has seen frequent use across populations despite lack of confirmatory factor-analytic examination. We further examine Brief COPE validity with respect to self- and other-directed aggression because emerging adulthood represents a distinct developmental time period in which stress, poor coping, and aggression intersect. Drawing on archival data (n = 576) from a larger investigation of college student health, this cross-sectional survey study tested (1) four competing Brief COPE factor structures, (2) Brief COPE factor associations with aggression, and (3) stress by coping interactions predicting aggression outcomes. Prominent findings included (1) poor-to-marginal confirmatory factor-analytic support for a four-factor structure; (2) positive bivariate associations of avoidant coping with elevated stress, depression, suicide, self-injury, and aggression; (3) positive bivariate associations between adaptive coping strategies with stress and aggression; and (4) an interaction where avoidant coping has a stronger association with other-directed aggression for those low in stress. The interaction findings were significant for males only and applied specifically to hostility. Findings are contextualized within future Brief COPE research as well as emerging adulthood theory.

Integrating Interprofessional Education into Suicide Prevention Training: Results from A Pilot Evaluation

Suicide prevention training for health professions students is lacking, often occurring in disciplinary silos. The present study reports outcomes from an interprofessional education (IPE)-based suicide prevention course for health professions students across a variety of disciplines (e.g., social work, counseling, public health). Using a quasi-experimental design, students either took part in a fully online or blended version of the course. Primary outcomes included: (1) significant moderate-to-large positive gains in suicide prevention knowledge, perceived clinical care skills, and perceived ability to help self-harming patients; (2) moderate positive shifts in sensitivity to risk factors of those who died by suicide; (3) non-significant impacts on IPE-related outcomes; (4) overall high course satisfaction; and (5) students in the blended course preferred several interactive methods more than students in the online course version (large effects). Recommendations are provided for course revision and future implementation in educational and community-based settings.

Community Mental Health Provider Responses to a Competency-Based Training in Suicide Risk Assessment and Prevention

The present study evaluates of a competency-based suicide prevention training. A sample of community mental healthcare providers took part in a suicide risk assessment and prevention training, completing pre-post measures of knowledge, competency/skill and attitudes, as well as baseline interprofessional education (IPE) socialization. Training yielded moderate-to-large improvements in suicide-related knowledge, perceived risk assessment/prevention skills, attitudes toward helping patients, and professional capacity to work with suicidal patients. Small pre-post differences were observed recognizing the need for additional training. IPE socialization moderated impacts on professional capacity. This study offers support for the promising impacts of competency-based and IPE-specific training.

A systematic review of interventions for healthcare professionals to improve screening and referral for perinatal mood and anxiety disorders

Postpartum depression affects approximately 11% of women. However, screening for perinatal mood and anxiety disorders (PMAD) is rare and inconsistent among healthcare professionals. When healthcare professionals screen, they often rely on clinical judgment, rather than validated screening tools. The objective of the current study is to review the types and effectiveness of interventions for healthcare professionals that have been used to increase the number of women screened and referred for PMAD. Preferred Reporting Items for Systematic Reviews and Meta-Analyses was utilized to guide search and reporting strategies. PubMed/Medline, PsychInfo/PsychArticles, Cumulative Index to Nursing, Allied Health Literature (CINAHL), and Health Source: Nursing/Academic Edition databases were used to find studies that implemented an intervention for healthcare professionals to increase screening and referral for PMAD. Twenty-five studies were included in the review. Based on prior quality assessment tools, the quality of each article was assessed using an assessment tool created by the authors. The four main outcome variables were the following: percentage of women screened, percentage of women referred for services, percentage of women screened positive for PMAD, and provider knowledge, attitudes, and/or skills concerning PMAD. The most common intervention type was educational, with others including changes in electronic medical records and standardized patients for training. Study quality and target audience varied among the studies. Interventions demonstrated moderate positive impacts on screening completion rates, referral rates for PMAD, and patient-provider communication. Studies suggested positive receptivity to screening protocols by mothers and providers. Given the prevalence and negative impacts of PMAD on mothers and children, further interventions to improve screening and referral are needed.

On hate crime victimization: Rates, types, and links with suicide risk among sexual orientation minority special interest group members

Hate crimes remain pressing traumatic events for sexual orientation minority adults. Previous literature documents patterns in which hate crime victimization is associated with elevated risk for poor mental health. The present paper held 2 aims to advance literature. First, we investigated the rates and types of hate crime victimization among sexual orientation minority adults. Second, adopting a mental health amplification risk model, we evaluated whether symptoms of depression, impulsivity, or post-traumatic stress exacerbated the hate crime victimization-suicide risk link. Participants were 521 adult sexual orientation minority-identifying members of the National Coalition for Sexual Freedom (i.e., a bondage and discipline, and sadomasochism-identifying sexuality special interest group). Participants completed demographic and mental health inventories via online administration. Results showed: (1) low rates of total lifetime hate crime victimization and (2) higher rates of interpersonal violence compared to property crime victimization within the sample. Regression results showed: (1) independent positive main effects of all 3 mental health symptom categories with suicide risk; (2) an interaction pattern in which impulsivity was positively associated with suicide risk for non-victims; and (3) an interaction pattern in which post-traumatic stress was positively associated with suicide risk for hate crime victims and non-victims. Results are discussed concerning implications for trauma-informed mental healthcare, mental health amplification models, and hate crime and suicide prevention policies.

Studies on the conformation and interactions of elastin: nuclear magnetic resonance of the polyhexapeptide

Synthesis, proton magnetic resonance and carbon-13 magnetic resonance characterizations, including complete assignments, are reported for the polyhexapeptide of elastin, HCO-Val(Ala1-Pro2-Gly3-Val4-Gly5-Val6)18-OMe. Temperature dependence of peptide NH chemical shifts and solvent dependence of peptide C-O chemical shifts have been determined in several solvents and have been interpreted in terms of four hydrogen bonded rings for each repeat of the polyhexapeptide. The more stable hydrogen bonded ring is a beta-turn involving Ala1C-O--HN-Val4. More dynamic hydrogen bonds are an 11-atom hydrogen bonded ring Gly3NH--O-C Gly5, a 7-atom hydrogen bonded ring (a gamma-turn) Gly3 C-O--NH-Gly5, and a 23-atom hydrogen bonded ring Val6inH--O-C Val6(i+1). This set of hydrogen bonds results in a right-handed beta-spiral structure with slightly more than two repeats (approximately 2.2) per turn of spiral. The beta-spiral structure is briefly discussed relative to data on the elastic fiber.

Protein crystal growth and the International Space Station

Protein structural information plays a key role in understanding biological structure-function relationships and in the development of new pharmaceuticals for both chronic and infectious diseases. The Center for Macromolecular Crystallography (CMC) has devoted considerable effort studying the fundamental processes involved in macromolecular crystal growth both in a 1-g and microgravity environment. Results from experiments performed on more than 35 U.S. space shuttle flights have clearly indicated that microgravity can provide a beneficial environment for macromolecular crystal growth. This research has led to the development of a new generation of pharmaceuticals that are currently in preclinical or clinical trials for diseases such as cutaneous T-cell lymphoma, psoriasis, rheumatoid arthritis, AIDS, influenza, stroke and other cardiovascular complications. The International Space Station (ISS) provides an opportunity to have complete crystallographic capability on orbit, which was previously not possible with the space shuttle orbiter. As envisioned, the x-ray Crystallography Facility (XCF) will be a complete facility for growing protein crystals; selecting, harvesting, and mounting sample crystals for x-ray diffraction; cryo-freezing mounted crystals if necessary; performing x-ray diffraction studies; and downlinking the data for use by crystallographers on the ground. Other advantages of such a facility include crystal characterization so that iterations in the crystal growth conditions can be made, thereby optimizing the final crystals produced in a three month interval on the ISS.

Differential effects of the intraventricular administration of 6-hydroxydopamine on the induction of type II beta-tubulin and tyrosine hydroxylase mRNA in the locus coeruleus of the aging Fischer 344 rat

Noradrenergic neurons of the locus coeruleus have been shown to respond to injury by increasing the synthesis of neurotransmitter (via the activation and induction of tyrosine hydroxylase, the rate-limiting catalyst in the production of catecholamines) and initiating compensatory axonal sprouting. However, this laboratory has recently described a significant deficit in the activation of tyrosine hydroxylase in the aged Fischer 344 rat, in contrast to the young and mature rat, following partial damage to cortical and hippocampal noradrenergic terminals induced by the neurotoxin 6-hydroxydopamine. To extend these observations, we measured changes in the relative levels of neuron-specific type II beta-tubulin and tyrosine hydroxylase mRNA in locus coeruleus neurons of 2, 12, and 24-month-old Fischer 344 rats following intraventricular infusions of 6-hydroxydopamine by using in situ hybridization histochemistry. These measures were used as markers of the responsiveness of these neurons to injury. 6-Hydroxydopamine treatment induced a persistent increase (at least 10 days) in the expression of type II beta-tubulin mRNA only in 2-month-old animals; this marker decreased in the 12 and 24-month-old animals. Relative levels of tyrosine hydroxylase mRNA increased in 2 and 12-month-old lesioned animals both 3 and 10 days post-treatment. In contrast, the induction of tyrosine hydroxylase mRNA in 24-month-old animals, seen three days post-treatment, was attenuated by 10 days. These data indicate that the capacity of locus coeruleus neurons to compensate for injury by either initiating a potential sprouting response or increasing their capacity to synthesize neurotransmitter is reduced in older animals.

Protein crystal growth in microgravity-temperature induced large scale crystallization of insulin

One of the major stumbling blocks that prevents rapid structure determination using x-ray crystallography is macromolecular crystal growth. There are many examples where crystallization takes longer than structure determination. In some cases, it is impossible to grow useful crystals on earth. Recent experiments conducted in conjunction with NASA on various Space Shuttle missions have demonstrated that protein crystals often grow larger and display better internal molecular order than their earth-grown counterparts. This paper reports results from three Shuttle flights using the Protein Crystallization Facility (PCF). The PCF hardware produced large, high-quality insulin crystals by using a temperature change as the sole means to affect protein solubility and thus, crystallization. The facility consists of cylinders/containers with volumes of 500, 200, 100, and 50 ml. Data from the three Shuttle flights demonstrated that larger, higher resolution crystals (as evidenced by x-ray diffraction data) were obtained from the microgravity experiments when compared to earth-grown crystals.

Elastin repeat peptides as chemoattractants for bovine aortic endothelial cells

Cultured bovine aortic endothelial cells migrate toward a concentration gradient of repeating elastin peptides, specifically the repeating nonamers Gly-Phe-Gly-Val-Gly-Ala-Gly-Val-Pro and Gly-Leu-Gly-Val-Gly-Ala-Gly-Val-Pro and the repeating hexamer Val-Gly-Val-Ala-Pro-Gly. Dose-response experiments demonstrate that the peak of activity occurs at 8 x 10(-8) M for the nonapeptides and 1 x 10(-8) M for the hexapeptide. Checkerboard assays establish that the movement is chemotaxis and not chemokinesis. Because of the concentration difference in the responsiveness between the nonapeptide and the hexapeptide, the cells can differentiate between the two types of repeats. The positive control for the chemotaxis studies was fibronectin.

A synthetic polypentapeptide of elastin for initiating calcification

A polypentapeptide (PPP) of tropoelastin having a repeating amino acid sequence of (Val-Pro-Gly-Val-Gly)n was evaluated for its potential to initiate in vivo calcification and to enhance bone formation in nonhealing calvarial wounds (8.0 mm) in 396 adult Walter Reed rats. There were four configurations of the PPP (molecular weight range of 50-100K dalton) consisting of 1-dry PPP; 2-coacervate PPP; 3-gamma irradiated, cross-linked PPP; 4-calcified, gamma irradiated, cross-linked PPP. These four iterations plus a control group of animals constituted the five treatment classes that were evaluated at days 1, 3, 7, 21, 42, and 147. Seventy two rats were used for each treatment and 36 rats for the control. Following euthanatization, specimens were placed into 70% ethanol, embedded in polymethyl methacrylate, sectioned at 3.5 micrometers, and alternating sections were stained with Masson-Goldner trichrome and von Kossa stains. Histomorphometric analysis was accomplished using a Zeiss Universal microscope (250 X) and Videoplan Image Analysis System to evaluate five random histologic fields from margin to margin of the craniotomy. Trabecular bony volume and area of calcification islands were quantitated. A Student's t test for unpaired data to determine treatment differences (within the same temporal groups) revealed that there was no significant difference between treatments and control for trabecular bony volume; however, there was a significant difference between experimentals and control for calcification islands (P less than 0.05) such that calcifications islands for the experimentals were greater than the control. There was not a significant difference between experimental treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemotaxis of fibroblasts toward nonapeptide of elastin

Bovine ligamentum fibroblasts, which produce elastin, migrate towards a positive chemical gradient of human platelet-derived growth factor and of the tropoelastin repeat hexapeptide Val-Gly-Val-Ala-Pro-Gly, as previously shown. They are also responsive to two permutations of a nonapeptide that repeats in tropoelastin, i.e., Ala-Gly-Val-Pro-Gly-Phe-Gly-Val-Gly and Gly-Phe-Gly-Val-Gly-Ala-Gly-Val-Pro. Concentration curves and checkerboard assays prove that the nonapeptides are chemoattractants. The component pentapeptide, Gly-Phe-Gly-Val-Gly, is chemotactic, while the component tetrapeptide Ala-Gly-Val-Pro is not. The hexapeptide competitively suppresses the nonapeptide chemotaxis suggesting the involvement of a common cell receptor. The results support the concept that elastin has multiple cell recognition sites as measured by the chemotactic response and that among the hydrophobic repeating sequences of elastin chemotacticity is selectively and multiply localized.

Cell attachment and chemotaxis can utilize the same peptide sequence of fibronectin

Fibronectin and fragments of the parent molecule are involved in cell-substrate attachment, cell migration and chemotaxis. The cell attachment sequence, Gly-Arg-Gly-Asp-Ser-Pro, was synthesized and tested for its ability to effect ligamentum nuchae fibroblast chemotaxis. This hexapeptide and fibronectin itself both caused directed cell migration, with maximal activity in the 10(-10) to 10(-9) M range. These data demonstrate that the fibronectin cell binding site and chemotaxis site share a common sequence.

Temperature dependence of dielectric relaxations in alpha-elastin coacervate: evidence for a peptide librational mode

The dielectric permittivity of alpha-elastin coacervate is reported over the frequency range of 1 MHz to 1000 MHz and the temperature dependence from 6.8 degrees C to 70 degrees C is also reported. A temperature-dependent simple Debye-type relaxation is observed with a correlation time of 8 nsec (40 degrees C) which is similar to that of the polypentapeptide of elastin (i.e. 7 nsec at 40 degrees C) where the band has been assigned to a peptide librational mode. By analogy this allows for the first assignment of a peptide librational mode in a naturally occurring polypeptide or protein. The strong spectrally localized band indicates a regularity of structure. The low temperature dependence of the correlation time, giving a 1.7 kcal/mole enthalpy of activation, is consistent with torsional motions associated with a peptide librational mode.

Synthesis of polypeptide models of elastin. Synthesis and properties of a cross-linked polytetrapeptide

Synthesis of two copolymers, H-(phi-Pro-Gly-Gly)n-Val-OMe and H-(phi'-Pro-Gly-Gly)n-Val-OMe, where phi is Val or Lys and phi' is Val or Glu is described. Cross-linking between the two copolymers is achieved by a coupling reaction between the epsilon-amino groups of the lysine containing copolymer and delta-carboxyls of the glutamic acid of the other copolymer. The cross-linking reaction was performed during a temperature elicited phase separation with flow orientation of the copolymers. Coacervation of the intermediate polymers is presented, as is the scanning electron micrograph of the insoluble cross-linked product and its calcifiability as determined with electron probe microanalysis. The purity of the key intermediates and polymers is demonstrated by the usual analytical methods. Carbon-13 magnetic resonance spectra of the intermediate monomer units are included to validate the purity of their synthesis.

Irradiation crosslinking of the polytetrapeptide of elastin and compounding to dacron to produce a potential prosthetic material with elasticity and strength

The poly(tetra peptide), H-(L . Val1-L . Pro2-Gly3-Gly4)n-L . Val-OMe, which is a recurring sequence in tropoelastin the precursor protein of the elastic fiber, has been irradiation crosslinked to produce an elastomeric material with limited strength. When a material such as a Dacron fabric is impregnated by the coacervate phase of the poly(tetrapeptide) prior to irradiation crosslinking at 50 Mrad, the crosslinked product exhibits stress-strain curves with good elastomeric properties and high strength. In addition to the stress-strain curves, the material is characterized by scanning electron microscopy.

Compounding of elastin polypentapeptide to collagen analogue: a potential elastomeric prosthetic material

The polypentapeptide, H-(L . Val1-L . Pro2-Gly3-L . Val4-Gly5)n-L . Val-OMe, which is the most common recurring sequence within the elastic fiber, is demonstrated to be elastomeric when irradiation cross-linked but to have limited strength. On irradiation compounding with a collagen analogue, such as Dacron, stress-strain studies show the product to have an elastic modulus greater than that of fibrous aortic elastin and similar to that of aortic wall. In addition, the compounded product has the requisite strength. Of the 40, 50 and 60 MRAD cross-linked polypentapeptide-Dacron products, those derived from the larger doses of 50 and 60 MRAD exhibited somewhat better elastomeric properties. The unstretched and stretched products were characterized by scanning electron microscopy which demonstrated the importance of a fabric weave with a uniform extension. In general irradiation cross-linking has the advantage of being able to produce larger quantities of elastomeric material and compounding to a collagen analogue provides the required strength.

Cyclic analog of elastin polyhexapeptide exhibits an inverse temperature transition leading to crystallization

The cyclic dodecapeptide analog of the linear polyhexapeptide of tropoelastin crystallizes from water on raising of the temperature and thereby demonstrates an inverse temperature transition implying dominant intermolecular hydrophobic interactions. The temperature profiles of turbidity (TP tau) of the cyclododecapeptide are analogous to those of the polyhexapeptide where increases in concentration lead to translations of the profiles to lower temperature without sharpening of the transition. The demonstration of increase in order with increase in temperature for the cyclododecapeptide in water and the similarity of TPtau's lends credence to the view that increases in temperature lead to increases in order, specifically, for the linear polyhexapeptide and, generally, for the precursor protein of the elastic fiber wherein the repeating hexapeptide occurs.

Synthetic, cross-linked polypentapeptide fo tropoelastin: an anisotropic, fibrillar elastomer

Physical properties of the cross-linked polypentapeptide of tropoelastin are reported along with chemical characterization of key intermediates in its synthesis. 220 MHz proton magnetic resonance spectra are reported on the constituent pentamers and their respective high polymers which verify structural and conformational integrity. Scanning electron microscopy of the cross-linked material formed without orientation and with flow orientation is reported. The former demonstrates the inherent fibrillar and anisotropic nature of the synthetic product. Stress-strain studies show the cross-linked polypentapeptide to exhibit elastomeric properties that are dependent on the water content of the matrix. At high water contents the elastic modulus is less than that of wet native aortic elastin and becomes greater on drying.

Cross-linked polypentapeptide of tropoelastin: an insoluble, serum calcifiable matrix

The synthetic, cross-linked polypentapeptide of tropoelastin has been shown to calcify from serum alone even when separated from the serum medium by a dialysis membrane with a low-molecular-weight cut off. By microprobe analysis, it appeared that the only serum elements required for the calcification were calcium and phosphorus. Furthermore, thin sections of the calcified matrix showed the calcification to occur throughout the matrix, and thereby verified that it is a bulk property of the matrix and not an interfacial property. To our knowledge this is the first demonstration of an insoluble, synthetic polypeptide to function as a serum calcifiable matrix and by doing so it opens the door to potential medical applications.

Calcification of alpha-elastin coacervates: a bulk property of elastin

Scanning electron microscopy and electron probe microanalysis studies are reported on thin sections of calcified coacervates of alpha-elastin. It is found that the capacity of elastin coacervates to initiate calcification is a bulk property of the coacervate and not limited to the serum-coacervate interface, that the calcium phosphate deposits act to bind the protein units together and slow the dissolution and spreading of the coacervate as it floats on an airwater interface, and that, within the limits of detectability, there is no involvement of sulfur. As the charged groups of alpha-elastin had been blocked, the initiation of deposition is due to neutral sites in the protein which are tightly bound to the calcium phosphate deposits.