An Investigation of the Dimensional Stability of Dental Alginates

Dimensional stability was defined by Nicholls (1977) as “the ability (of a material) to maintain accuracy over time”, and the result of loss of accuracy, “distortion”, as “the relative movement of a single point, or group of points, away from some originally specified reference position such that permanent deformation is apparent”. Maintaining dimensional stability of dental impression materials is vital if the impression cannot be cast (in stone) soon after removal from the mouth. Dental irreversible hydrocolloid (alginate) is a major dental impression material used worldwide in many clinical procedures. However, alginate is dimensionally unstable and changes its dimensions (suffers “distortion”) after removal from the mouth. With storage times of more than ten minutes, alginate begins to distort, and after one to three hours (depending on the product and storage conditions) cannot be used for many clinical purposes, especially fixed prosthodontics such as crowns and bridges (Hampson 1955, Skinner & Hoblit 1956, Wilson & Smith 1963, Rudd et al. 1969, Miller 1975, Inohara 1977, Schoen et al. 1978, Coleman et al. 1979, Linke et al. 1985, Habu et al. 1986, Peutfeldt & Asmussen 1989, Mathilde & Peters 1992, Khan & Aziz Sahu 1995, Eriksson et al. 1998, Schleier et al. 2001, and Donovan & Chee 2004). This loss of accuracy, due to dimensional instability, manifests as a time-dependent distortion of the poured stone cast, and thus any prosthesis fabricated will not fit in the mouth. With the introduction of the more stable elastomers in the 1950s (Stackhouse 1970, Glenner 1997, Brown 2003) that could be stored for days if necessary, without loss of accuracy, the alginates fell out of favour for fixed prosthodontics. Recently, there has been a resurgence of interest in alginate for use in dental procedures where dimensional stability is critical (Peutzfeldt and Asmussen 1989, Eriksson et al. 1998). This in part is due to the favourable properties of alginate not found in the elastomers. Of greatest significance is that alginate hydrocolloid is hydrophilic, whereas elastomers are hydrophobic (Phillips & Ito 1958, Glenner 2004). Thus, alginate materials are able to reproduce wet oral areas with greater precision and to produce a superior "fit" of, say, a gold casting produced by the Lost Wax technique (Skinner and Phillips 1982). A number of reports have been published which investigate newer alginate materials that are claimed to be more dimensionally stable than older formulations. Puetzfeldt and Asmussen (1989) found that a newer alginate , if stored at 100% relative humidity, retained accuracy over 24 hours that was equivalent to that of the elastomers. More recently, the manufacturer of another alginate has claimed equivalent dimensional stability to the elastomers for up to 100 hours, and, whilst this claim has not been reported on in the literature, the present thesis will show that, under favourable conditions of storage, the material maintained clinically useful accuracy for up to 100 hours. Another approach to improving the accuracy of alginate impressions has been to combine reversible hydrocolloid with alginate (the “Bilaminar” technique). Frederick and Caputo (1997) confirmed that the new agar reversible hydrocolloids are just as accurate (at the time of removal from the mouth) as the new elastomers. Mathilde et al. (1992) and Eriksson et al. (1998) have shown that several of the “bilaminar” impression techniques for fixed prosthodontics, where alginate is used as a tray material supporting a reversible hydrocolloid (agar) wash, are as accurate and dimensionally stable as elastomers for up to three hours. However, these studies are difficult to interpret due to lack of uniformity in the testing methods, and the fact that there is no regulatory standard available to measure dimensional stability for dental alginates. The International Standard (IS) for alginate impression materials (ISO 1563:1990E) contains no specification for dimensional stability, and thus places no requirement for manufacturers to state dimensional stability properties on their labels. In contrast, ISO 4823:1992(E) specifies the IS for elastomeric dental impression materials, and it does specify a requirement for dimensional stability (less than 1.5% distortion after 24 hours). Further, the IS sets a method for determination of dimensional stability. Briefly, this method (the Optical Method) uses a travelling optical microscope to measure the accuracy of the distance between score lines on an impression of a test grid, at various time periods. The American Dental Association Specification No. 19 for dental elastomeric impression materials is identical to the IS. There is currently no specific Australian Standard (AS) for the dimensional stability of any dental impression material. Overview of Experimental Methods A. The Optical Method The aim of Part A of this investigation was to: 1. Adapt the Optical Method of the IS for elastomers to be reproducible for dental alginates. This was achieved by using a perforated test tray (to simulate clinical conditions), and measuring the grid pattern on a dental stone button after casting the test impression, rather than direct measurement of the impression, as for the IS. 2. To measure and rank the dimensional stability of a number of locally available dental alginates. Measurements of the test stone buttons proved reproducible, and the results were different for each sample, allowing them to be ranked according to dimensional stability after 50 and 100 hours of storage. The results show that the traditional optical method for measuring dimensional stability, as specified in the IS for dental elastomers, can be adapted to measure the dimensional stability of dental alginates However, the Optical Method of measuring dimensional stability of dental alginates is cumbersome and time-consuming. It was hypothesised that dimensional stability of dental alginates could be measured more conveniently by finding a thermal property that is directly proportional to dimensional stability. This method could be useful for the rapid determination of relative performance, and allow comparison with a determined benchmark. B. The Thermal Method Recently, modern methods of Thermal Analysis, Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) have been used to rapidly age various polymers, including food alginates (Chinachoti 1996), in order to measure thermal stability. This thesis shows that thermal stability is an indicator of dimensional stability. The aim of Part B of this investigation was therefore to adapt thermal analysis techniques to dental alginates, and develop a method to measure their thermal stability. These results were then compared with those for dimensional stability measured by the Optical Method to determine the relationship between thermal and dimensional stability for dental alginates. The results show that current thermal analysis methods of TGA and DSC can be adapted to measure relative dental alginate dimensional stability, and are both rapid and convenient. This study also provides evidence that commercial products differ as regards the property of dimensional stability, and can be ranked accordingly. C. Practical Application of the Methods The aim of part C of this thesis was to validate the methods (both optical and thermal) developed in this study by using them to investigate the effect of varying the water/powder ratio on the dimensional stability of dental alginates. It was shown that dimensional stability is affected by changes to the recommended water/powder ratio, that both the methods detected and measured the changes, and that the results were proportional, in that any percentage change detected by the optical method, was mirrored by the thermal method, confirming that the more convenient thermal methods can be used to measure dimensional stability

Smoke, alcohol and drug addiction and male fertility

In recent decades, the decline in human fertility has become increasingly more worrying: while therapeutic interventions might help, they are vexing for the couple and often burdened with high failure rates and costs. Prevention is the most successful approach to fertility disorders in males and females alike. We performed a literature review on three of the most common unhealthy habits - tobacco, alcohol and drug addiction - and their reported effects on male fertility. Tobacco smoking is remarkably common in most first-world countries; despite a progressive decline in the US, recent reports suggest a prevalence of more than 30% in subjects of reproductive age - a disturbing perspective, given the well-known ill-effects on reproductive and sexual function as well as general health. Alcohol consumption is often considered socially acceptable, but its negative effects on gonadal function have been consistently reported in the last 30 years. Several studies have reported a variety of negative effects on male fertility following drug abuse - a worrying phenomenon, as illicit drug consumption is on the rise, most notably in younger subjects. While evidence in these regards is still far from solid, mostly as a result of several confounding factors, it is safe to assume that cessation of tobacco smoking, alcohol consumption and recreational drug addiction might represent the best course of action for any couple trying to achieve pregnancy

How much does obesity affect the male reproductive function?

Obesity is considered a worldwide epidemic disease. Many pathological conditions have been associated to obesity but the evidence relating to impaired fertility in males with obesity are contrasting. The aim of this review was to evaluate the interplay between obesity and male fertility, analyzing evidence from in vitro and in vivo studies to clinical trials. Obesity seems to be responsible of secondary hypogonadism. Here, we propose a new classification including central, peripheral and testicular factors that may affect the hypothalamic-pituitary-gonadal axis. Moreover, some studies demonstrated a direct action of obesity on sperm count and sperm characteristics, mediated by impaired Sertoli cells function, increased scrotal temperature, oxidative stress and accumulation of toxic substances and liposoluble endocrine disruptors in fat tissue. Recent studies have explored obesity-related epigenetic effects in sperm cells which may cause diseases in offspring. Moreover, not only in females but also males, obesity has been linked to reduced outcomes of in vitro fertilization, with a reduction of pregnancy rate and an increase of pregnancy loss. Finally, we reviewed the effects of weight modifications through diet or bariatric surgery on obesity-related reproductive dysfunction. In this regard, several studies have demonstrated that weight loss has been associated with a restoration of gonadal hormones levels

Smoke, alcohol and drug addiction and male fertility

In recent decades, the decline in human fertility has become increasingly more worrying: while therapeutic interventions might help, they are vexing for the couple and often burdened with high failure rates and costs. Prevention is the most successful approach to fertility disorders in males and females alike. We performed a literature review on three of the most common unhealthy habits - tobacco, alcohol and drug addiction - and their reported effects on male fertility. Tobacco smoking is remarkably common in most first-world countries; despite a progressive decline in the US, recent reports suggest a prevalence of more than 30% in subjects of reproductive age - a disturbing perspective, given the well-known ill-effects on reproductive and sexual function as well as general health. Alcohol consumption is often considered socially acceptable, but its negative effects on gonadal function have been consistently reported in the last 30 years. Several studies have reported a variety of negative effects on male fertility following drug abuse - a worrying phenomenon, as illicit drug consumption is on the rise, most notably in younger subjects. While evidence in these regards is still far from solid, mostly as a result of several confounding factors, it is safe to assume that cessation of tobacco smoking, alcohol consumption and recreational drug addiction might represent the best course of action for any couple trying to achieve pregnancy

Formalidad, informalidad y precariedad en las relaciones laborales de la Argentina actual. Un estudio multisectorial en el municipio de La Matanza

La dinámica del trabajo informal y formal en la Argentina y la tendencia de las relaciones laborales en un contexto de crecimiento económico sostenido a partir del año 2003 son los ejes temáticos que venimos abordando en diferentes proyectos de investigación que nos han consolidado como equipo de trabajo. Los resultado de estos proyectos de investigación (UNLaM, SOC OO3/2006 y SOC 013/2008) señalan que a pesar del crecimiento del empleo formal entre 2003 y 2011 persisten contradicciones y dificultades del mercado laboral argentino, que exhibe aún una alta incidencia de empleo informal y de aspectos precarios en el formal. La perseverancia de estos indicadores a lo largo de los últimos años y su convivencia con la recuperación de la negociación colectiva y el fortalecimiento de los sindicatos, así como del rol del Estado en estos procesos, nos llevan a interrogarnos nuevamente sobre los vínculos entre estos dos aspectos del mercado laboral argentino. Así, el trabajo de investigación que sobre el que hemos avanzado busca reflexionar sobre las tensiones que se generan entre las mejoras de los indicadores de empleo y participación sindical, por un lado, y, por otro, la subsistencia de rasgos que suelen caracterizarse como “heredados” del contexto anterior (el modelo neoliberal de los años 90). En este sentido, la pregunta que guía nuestro análisis es si esa “herencia” funciona como un factor estable en el marco de una reconfiguración de las relaciones laborales, la cual se articula con aspectos productivos que sostienen la economía argentina actual. Con ese propósito propusimos estudiar tres sectores económicos en el municipio de La Matanza: transporte y logística, calzado y comercio, entre 2003 y 2011. Nuestra propuesta metodológica busca analizar las interrelaciones de los actores empresarial, estatal y sindical en cada uno de los sectores. Finalmente, y por cuestiones que desarrollaremos más adelante, nos centramos en dos sectores: calzados y logística.Fil: Schettini, Patricia. Universidad Nacional de La Matanza; Argentina.Fil: Pontoni, Gabriela Alejandra. Universidad Nacional de La Matanza; Argentina.Fil: Radiciotti, Luisina. Universidad Nacional de La Matanza; Argentina.Fil: Salomón, Guadalupe. Universidad Nacional de La Matanza; Argentina.Fil: Menafra, Micaela. Universidad Nacional de La Matanza; Argentina.Fil: Ungaro, Valeria. Universidad Nacional de La Matanza; Argentina

The role of vitamin D in male fertility: A focus on the testis

In the last decade, vitamin D has emerged as a pleiotropic molecule with a multitude of autocrine, paracrine and endocrine functions, mediated by classical genomic as well as non-classical non-genomic actions, on multiple target organs and systems. The expression of vitamin D receptor and vitamin D metabolizing enzymes in male reproductive system, particularly in the testis, suggests the occurrence of vitamin D synthesis and regulation as well as function in the testis. The role of vitamin D in the modulation of testis functions, including hormone production and spermatogenesis, has been investigated in animals and humans. Experimental studies support a beneficial effect of vitamin D on male fertility, by modulating hormone production through genomic and non-genomic actions, and, particularly, by improving semen quality essentially through non-genomic actions. However, clinical studies in humans are controversial. Indeed, vitamin D seems to contribute to the modulation of the bioavailable rather than total testosterone. Moreover, although an increased prevalence or risk for testosterone deficiency was reported in men with vitamin D deficiency in observational studies, the majority of interventional studies demonstrated the lack of effect of vitamin D supplementation on circulating levels of testosterone. The most consistent effect of vitamin D was reported on semen quality. Indeed, vitamin D was shown to be positively associated to sperm motility, and to exert direct actions on spermatozoa, including non-genomic driven modulation of intracellular calcium homeostasis and activation of molecular pathways involved in sperm motility, capacitation and acrosome reaction. The current review provides a summary of current knowledge on the role of vitamin D in male fertility, by reporting clinical and experimental studies in humans and animals addressing the relationship between vitamin D and testis function

Aumento del riesgo de enfermedad cardiovascular en pacientes con enfermedad celíaca

En pacientes con enfermedad celíaca (EC), se ha observado mayor incidencia de eventos cardiovasculares que en controles, sin la presencia de factores de riesgo aterogénico clásicos. El objetivo de este estudio fue evaluar los factores de riesgo nóveles y biomarcadores de inflamación y enfermedad cardiovascular en pacientes con EC, con presentación típica y atípica. Fueron seleccionados 14 pacientes con EC sin tratamiento y controles pareados por sexo y edad. Se determinaron parámetros hematológicos, indicadores del metabolismo de los hidratos de carbono, proteína C reactiva ultrasensible (PCRus), per- fil lipoproteico y actividades de proteína transportadora de colesterol esterificado (CETP) y fosfolipasa A2 asociada a lipoproteínas (Lp-PLA2). Los pacientes con EC presentaron niveles plasmáticos mayores de insulina (7,2 mU/l vs. 4,4 mU/l; p<0,05) y mayor índice HOMA-IR (1,45 vs. 0,98; p<0,05) que los controles. Por otro lado, se observó menor concentración de colesterol-HDL (50 vs. 62 mg/dl; p<0,05), mayor cociente triglicéridos/colesterol-HDL y niveles de PCRus más altos (4,56 vs. 1,17 mg/l; p<0,05) en los pacientes que en los controles. Al comparar a los pacientes con presentación típica (n=8) y atí- pica (n=6), aquellos con presentación típica mostraron menores niveles de apo A-I (128 vs. 178 mg/dl; p<0,01) y aumento del cociente apo B/apo A-I (0,72 vs. 0,43; p<0,05), así como mayor actividad de LpPLA2 (7,9 umol/ml.h vs. 6,15 umol/ml.h; p<0,05). La interacción de las alteraciones descriptas durante períodos de tiempo prolongados en una condición patológica crónica como la EC constituirían un mayor riesgo de desarrollo de enfermedad cardiovascular aterosclerótica.In patients with celiac disease (CD), it has been reported higher incidence of cardiovascular events than in controls, without the presence of classical atherogenic risk factors. The aim of this study was to evaluate the novel risk factors and biomarkers of inflammation and cardiovascular disease in patients with CD, with typical and atypical presentation. We selected 14 patients with CD without treatment and 14 healthy sex and age-matched controls. Haematological parameters, indicators of carbohydrates metabolism, high sensitive C reactive protein (hsCRP), lipoprotein profile and the activities of cholesteryl ester transfer protein (CETP) and lipoprotein-associated phospholipase A2 (Lp-PLA2) were determined. CD patients presented higher insulin plasma levels (7.2 mU/l vs. 4.4 mU/l, p <0.05) and increased HOMA-IR index (1.45 vs. 0.98, p <0.05) than controls. On the other hand, lower HDLcholesterol concentration (50 vs. 62 mg/dl, p<0.05), higher TG/HDL-cholesterol ratio and increased hsCRP levels (4.56 vs. 1.17 mg / l, P <0.05) were observed in comparison with control subjects. When comparing patients with typical (n=8) and atypical (n=6) presentation, the former showed lower apo A-I levels (128 vs. 178 mg/dl, p<0.01), and higher apo B/apo A-I ratio (0.72 vs. 0.43, p<0.05) and LpPLA2 activity (7.9 umol/ml.h vs. 6.15 umol/ml.h, p<0.05). The interaction among the alterations above described during long periods of time in a chronic pathological condition such as CD could constitute higher risk of development of atherosclerotic cardiovascular disease.Fil: Menafra, Martín. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Meroño, Tomás. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Matoso, María Dolores. Hospital Italiano; ArgentinaFil: Boero, Laura Estela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gomez Rosso, Leonardo Adrián. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Saez, María Soledad. Hospital Italiano; ArgentinaFil: Sorroche, Patricia Beatriz. Hospital Italiano; ArgentinaFil: de Paula, P.. Hospital Italiano; ArgentinaFil: Brites, Fernando Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Application of long-read sequencing to elucidate complex pharmacogenomic regions: a proof of principle

The use of pharmacogenomics in clinical practice is becoming standard of care. However, due to the complex genetic makeup of pharmacogenes, not all genetic variation is currently accounted for. Here, we show the utility of long-read sequencing to resolve complex pharmacogenes by analyzing a well-characterised sample. This data consists of long reads that were processed to resolve phased haploblocks. 73% of pharmacogenes were fully covered in one phased haploblock, including 9/15 genes that are 100% complex. Variant calling accuracy in the pharmacogenes was high, with 99.8% recall and 100% precision for SNVs and 98.7% precision and 98.0% recall for Indels. For the majority of gene-drug interactions in the DPWG and CPIC guidelines, the associated genes could be fully resolved (62% and 63% respectively). Together, these findings suggest that long-read sequencing data offers promising opportunities in elucidating complex pharmacogenes and haplotype phasing while maintaining accurate variant calling.Personalised Therapeutic

Markers of inflammation and cardiovascular disease in recently diagnosed celiac disease patients

AIM: To evaluate novel risk factors and biomarkers of cardiovascular disease in celiac disease (CD) patients compared with healthy controls.METHODS:Twenty adult patients with recent diagnosis of CD and 20 sex, age and body mass index-matched healthy controls were recruited during a period of 12 mo.Indicators of carbohydrate metabolism, hematological parameters and high sensitive C reactive protein were determined. Moreover, lipoprotein metabolism was also explored through evaluation of the lipid profile and the activity of cholesteryl ester transfer protein and lipoprotein associated phospholipase A2, which is also considered a specific marker of vascular inflammation. The protocol was approved by the Ethic Committee from School of Pharmacy and Biochemistry, University of Buenos Aires and from Buenos Aires Italian Hospital, Buenos Aires, Argentina.RESULTS: Regarding the indicators of insulin resistance, CD patients showed higher plasma insulin levels [7.2 (5.0-11.3) mU/L vs 4.6 (2.6-6.7) mU/L, P < 0.05], increased Homeostasis Model Assessment-Insulin Resistance [1.45 (1.04-2.24) vs 1.00 (0.51-1.45), P < 0.05] and lower Quantitative Sensitive Check index [0.33 (0.28-0.40) vs 0.42 (0.34-0.65), P < 0.05] indexes. Folic acid concentration [5.4 (4.4-7.9) ng/mL vs 12.2 (8.0-14.2) ng/mL, P < 0.01] resulted to be lower and High-sensitivity C reactive protein levels higher (4.21 ± 6.47 mg/L vs 0.98 ± 1.13 mg/L, P < 0.01) in the patient group. With respect to the lipoprotein profile, CD patients showed lower high density lipoproteincholesterol (HDL-C) (45 ± 15 mg/dL vs 57 ± 17 mg/dL, P < 0.05) and apo A-I (130 ± 31 mg/dL vs 155 ± 29 mg/ dL, P < 0.05) levels, as well as higher total cholesterol/ HDL-C [4.19 (3.11-5.00) vs 3.52 (2.84-4.08), P < 0.05] and apo B/apo A-I (0.75 ± 0.25 vs 0.55 ± 0.16, P < 0.05) ratios in comparison with control subjects. No statistically significant differences were detectedin lipoprotein-associated lipid transfer protein and enzymes.CONCLUSION: The presence and interaction of the detected alterations in patients with CD, would constitute a risk factor for the development of atherosclerotic cardiovascular disease.Fil: Tetzlaff, Walter Francisco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Meroño, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Menafra, Martín. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Martin, Maximiliano. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Botta, Eliana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Matoso, María Dolores. Hospital Italiano; ArgentinaFil: Sorroche, Patricia Beatriz. Hospital Italiano; ArgentinaFil: De Paula, Juan A. Hospital Italiano; ArgentinaFil: Boero, Laura Estela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Brites, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentin

Physical activity in the prevention of peripheral artery disease in the elderly

Aging is a well-known cardiovascular risk factor and cardiovascular diseases (CVD) are estimated to be the most common cause of death in the elderly. Peripheral arterial disease (PAD) represents an important clinical manifestation of CVD leading to increase morbidity and mortality, especially in elderly population. The correct management of PAD population includes the prevention of cardiovascular events and relief of symptoms, most commonly intermittent claudication. Progressive physical activity is an effective treatment to improve walking distance and to reduce mortality and cardiovascular events in patients with PAD, however the ability to effectively engage in physical activity often declines with increasing age. The maintenance and increase of reserve functional capacity are important concepts in the elderly population. Ultimately, the goal in participation of physical activity in the healthy elderly population is maintenance and development of physical functional reserve capacity. Therefore, for individuals suffering of PAD, appropriate physical activity in the form of supervised exercise may serve as a primary therapy. Although there are few direct comparisons of therapeutic exercise programs vs. pharmacological or surgical interventions, these increases in walking distance are greater than those reported for the most widely used agents for claudication, pentoxyphylline, and cilostazol. Despite a reduction in mortality and improvement of quality of life caused by physical activity in the PAD population, the molecular, cellular, and functional changes that occur during physical activity are not completely understood. Therefore, this review article aims at presenting an overview of recent established clinical and molecular findings addressing the role of physical activity on PAD in the older population