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1.
Artículo en Inglés | MEDLINE | ID: mdl-39212768

RESUMEN

Systemic inflammation is reported in normal-weight obesity (NWO) and metabolically healthy obesity (MHO), which may be linked to their increased cardiovascular disease (CVD) risk. Yet, drivers of this inflammation remain unclear. We characterized factors known to influence inflammatory status (i.e., intestinal permeability, adipose tissue, diet quality, microbiota) - and their relationships with measured inflammation - in NWO and MHO, healthy controls (CON) and metabolically unhealthy obesity (MUO; N=80; n=20/group). Serum indicators of intestinal permeability and inflammation were assessed using ELISA and/or multiplex. Total, visceral, and percent body fat were measured with dual-energy X-ray absorptiometry (DXA). Fecal microbiota composition was assessed via 16S rRNA sequencing (n=9-10/group). For C-reactive protein (CRP), MUO > NWO > CON (p<0.0001). In MHO, CRP was intermediate - and similar to - both MUO and NWO. Lipopolysaccharide binding protein (LBP) and the ratio of LBP to soluble CD14 (sCD14) were higher in MHO and MUO versus CON/NWO (p's<0.0001). Across correlation and regression analyses, LBP consistently displayed the strongest relationships with CRP in the entire sample (r=0.78;ß = 0.57;p's<0.0001) and in MHO (r=0.74;p<0.01), but not NWO (r=0.37;p = 0.11). Shannon index was higher in CON compared to MUO (p<0.05) and inversely correlated with CRP in the full sample (r=-0.37;p<0.05). These data are consistent with the notion that intestinal permeability is associated with low-grade inflammation in MHO, which could be implicated in this population's reported CVD risk.

2.
Nutr Metab Cardiovasc Dis ; 34(1): 121-125, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37788958

RESUMEN

BACKGROUND & AIMS: Elevated postprandial triglycerides are an independent cardiovascular disease risk factor and observed in older adults. However, differences in postprandial triglycerides across the spectrum of adulthood remain unclear. METHODS AND RESULTS: We performed a secondary analysis of six studies where adults (aged 18-84 years; N = 155) completed an abbreviated fat tolerance test (9 kcal/kg; 70% fat). Differences in postprandial triglycerides were compared in those ≥50 and <50 years and by decade of life, adjusting for sex and BMI. Compared to those <50 years, participants ≥50 years had higher fasting, 4 h, and Δ triglycerides from baseline (p's < 0.05). When examining triglyceride parameters by decade, no differences were observed for fasting triglycerides, but 50 s, 60 s, and 70s-80 s displayed greater 4 h and Δ triglycerides versus 20 s (p's ≤ 0.001). The frequency of adverse postprandial triglyceride responses (i.e., ≥220 mg/dL) was higher in participants ≥50 versus <50 years (p < 0.01), and in 60 s compared to all other decades (p = 0.01). CONCLUSION: Older age was generally associated with higher postprandial triglycerides, with no divergence across the spectrum of older adulthood. In our sample, postprandial triglyceride differences in older and younger adults were driven by those >50 years relative to young adults in their 20 s. REGISTRATION: N/A (secondary analysis).


Asunto(s)
Hipertrigliceridemia , Adulto , Anciano , Humanos , Adulto Joven , Envejecimiento , Ayuno , Hipertrigliceridemia/diagnóstico , Hipertrigliceridemia/epidemiología , Periodo Posprandial/fisiología , Triglicéridos , Persona de Mediana Edad
3.
Eur J Appl Physiol ; 124(4): 1131-1142, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37917417

RESUMEN

PURPOSE: Cardiorespiratory fitness (CRF) is critical for cardiovascular health. Normal-weight obesity (NWO) and metabolically healthy obesity (MHO) may be at increased risk for cardiovascular disease, but a comparison of CRF and submaximal exercise dynamics against rigorously defined low- and high-risk groups is lacking. METHODS: Four groups (N = 40; 10/group) based on body mass index (BMI), body fat %, and metabolic syndrome (MetS) risk factors were recruited: healthy controls (CON; BMI 18.5-24.9 kg/m2, body fat < 25% [M] or < 35% [F], 0-1 risk factors), NWO (BMI 18.5-24.9 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F]), MHO (BMI > 30 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F], 0-1 risk factors), or metabolically unhealthy obesity (MUO; BMI > 30 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F], 2 + risk factors). All participants completed a V ˙ O2peak test on a cycle ergometer. RESULTS: V ˙ O2peak was similarly low in NWO (27.0 ± 4.8 mL/kg/min), MHO (25.4 ± 6.7 mL/kg/min) and MUO (24.6 ± 10.0 mL/kg/min) relative to CON (44.2 ± 11.0 mL/kg/min) when normalized to total body mass (p's < 0.01), and adjusting for fat mass or lean mass did not alter these results. This same differential V ˙ O2 pattern was apparent beginning at 25% of the exercise test (PGroup*Time < 0.01). CONCLUSIONS: NWO and MHO had similar peak and submaximal CRF to MUO, despite some favorable health traits. Our work adds clarity to the notion that excess adiposity hinders CRF across BMI categories. CLINICALTRIALS: gov registration: NCT05008952.


Asunto(s)
Capacidad Cardiovascular , Síndrome Metabólico , Obesidad Metabólica Benigna , Humanos , Índice de Masa Corporal , Estado de Salud , Obesidad , Fenotipo , Factores de Riesgo
4.
Liver Int ; 41(5): 894-904, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33506572

RESUMEN

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver disease that is becoming more prevalent in concert with obesity and poor lifestyle habits. Although NAFLD is treatable via lifestyle modification in early stages, more advanced liver pathologies (eg non-alcoholic steatohepatitis [NASH]) are harder to reverse. There is no Food and Drug Administration approved pharmacological treatment for NAFLD, and little research has been done to identify compounds that target key NAFLD mechanisms. Bile acids and bile acid receptors have been implicated in NAFLD pathogenesis and modulating bile acids and bile acid receptors has recently been targeted as a therapeutic treatment option for NAFLD. Fibroblast growth factor 19 (FGF19), a nutritionally regulated post-prandial hormone, is a chief regulator of bile acid metabolism and an important player in lipid and carbohydrate metabolism, including key mechanisms of NAFLD pathogenesis. In this review, we discuss recent findings related to FGF19-regulated processes involved in the pathogenesis of NAFLD. We summarize known and conjectural frameworks and limitations for the clinical application of FGF19-targeted therapies as they relate to NAFLD.


Asunto(s)
Factores de Crecimiento de Fibroblastos , Enfermedad del Hígado Graso no Alcohólico , Ácidos y Sales Biliares/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Humanos , Metabolismo de los Lípidos , Hígado/metabolismo , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/metabolismo
5.
Am J Physiol Gastrointest Liver Physiol ; 319(4): G512-G518, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32845171

RESUMEN

Regular aerobic exercise has numerous benefits on human physiology, arguably by serving as a hormetic stressor resulting in positive adaptations over time. It has long been known that aerobic exercise at a variety of intensities and durations induces intestinal permeability, which is a feature of many pathologies of the gastrointestinal tract and metabolic diseases. Given the health benefits of exercise, it seems unlikely that intestinal permeability induced by exercise outweighs the positive adaptations. In fact, a growing body of evidence suggests adoption of exercise regimens lasting weeks to months improves indicators of intestinal permeability. In this brief review, we summarize factors contributing to acute exercise-induced intestinal permeability and what is known about chronic exercise and the gut barrier. Additionally, we outline known and theoretical adaptations of the gut to chronic exercise that may explain emerging reports that exercise improves markers of gut integrity.


Asunto(s)
Ejercicio Físico/fisiología , Hormesis/fisiología , Intestinos/fisiología , Sistema Cardiovascular , Absorción Gastrointestinal/fisiología , Microbioma Gastrointestinal/fisiología , Humanos , Inmunidad/fisiología , Mucosa Intestinal/fisiología , Permeabilidad , Circulación Esplácnica/fisiología , Termotolerancia/fisiología
6.
Bioorg Med Chem Lett ; 30(21): 127499, 2020 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-32858124

RESUMEN

Agonism of the endothelial receptor APJ (putative receptor protein related to AT1; AT1: angiotensin II receptor type 1) has the potential to ameliorate congestive heart failure by increasing cardiac output without inducing hypertrophy. Although the endogenous agonist, pyr-apelin-13 (1), has shown beneficial APJ-mediated inotropic effects in rats and humans, such effects are short-lived given its extremely short half-life. Here, we report the conjugation of 1 to a fatty acid, providing a lipidated peptide (2) with increased stability that retains inotropic activity in an anesthetized rat myocardial infarction (MI) model. We also report the preparation of a library of 15-mer APJ agonist peptide-lipid conjugates, including adipoyl-γGlu-OEG-OEG-hArg-r-Q-hArg-P-r-NMeLeuSHK-G-Oic-pIPhe-P-DBip-OH (17), a potent APJ agonist with high plasma protein binding and a half-life suitable for once-daily subcutaneous dosing in rats. A correlation between subcutaneous absorption rate and lipid length/type of these conjugates is also reported.


Asunto(s)
Receptores de Apelina/agonistas , Lípidos/farmacología , Infarto del Miocardio/tratamiento farmacológico , Péptidos/farmacología , Animales , Receptores de Apelina/metabolismo , Relación Dosis-Respuesta a Droga , Inyecciones Intravenosas , Lípidos/administración & dosificación , Lípidos/química , Estructura Molecular , Infarto del Miocardio/metabolismo , Péptidos/administración & dosificación , Péptidos/química , Ratas , Relación Estructura-Actividad
7.
Nature ; 499(7456): 107-10, 2013 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-23685453

RESUMEN

Eukaryotic Ca(2+) regulation involves sequestration into intracellular organelles, and expeditious Ca(2+) release into the cytosol is a hallmark of key signalling transduction pathways. Bulk removal of Ca(2+) after such signalling events is accomplished by members of the Ca(2+):cation (CaCA) superfamily. The CaCA superfamily includes the Na(+)/Ca(2+) (NCX) and Ca(2+)/H(+) (CAX) antiporters, and in mammals the NCX and related proteins constitute families SLC8 and SLC24, and are responsible for the re-establishment of Ca(2+) resting potential in muscle cells, neuronal signalling and Ca(2+) reabsorption in the kidney. The CAX family members maintain cytosolic Ca(2+) homeostasis in plants and fungi during steep rises in intracellular Ca(2+) due to environmental changes, or following signal transduction caused by events such as hyperosmotic shock, hormone response and response to mating pheromones. The cytosol-facing conformations within the CaCA superfamily are unknown, and the transport mechanism remains speculative. Here we determine a crystal structure of the Saccharomyces cerevisiae vacuolar Ca(2+)/H(+) exchanger (Vcx1) at 2.3 Å resolution in a cytosol-facing, substrate-bound conformation. Vcx1 is the first structure, to our knowledge, within the CAX family, and it describes the key cytosol-facing conformation of the CaCA superfamily, providing the structural basis for a novel alternating access mechanism by which the CaCA superfamily performs high-throughput Ca(2+) transport across membranes.


Asunto(s)
Antiportadores/química , Antiportadores/metabolismo , Calcio/metabolismo , Citosol/metabolismo , Protones , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/química , Secuencia de Aminoácidos , Sitios de Unión , Cristalografía por Rayos X , Transporte Iónico , Methanococcus/química , Modelos Moleculares , Datos de Secuencia Molecular , Conformación Proteica , Pliegue de Proteína , Relación Estructura-Actividad
8.
Nature ; 496(7446): 533-6, 2013 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-23542591

RESUMEN

Phosphate is crucial for structural and metabolic needs, including nucleotide and lipid synthesis, signalling and chemical energy storage. Proton-coupled transporters of the major facilitator superfamily (MFS) are essential for phosphate uptake in plants and fungi, and also have a function in sensing external phosphate levels as transceptors. Here we report the 2.9 Å structure of a fungal (Piriformospora indica) high-affinity phosphate transporter, PiPT, in an inward-facing occluded state, with bound phosphate visible in the membrane-buried binding site. The structure indicates both proton and phosphate exit pathways and suggests a modified asymmetrical 'rocker-switch' mechanism of phosphate transport. PiPT is related to several human transporter families, most notably the organic cation and anion transporters of the solute carrier family (SLC22), which are implicated in cancer-drug resistance. We modelled representative cation and anion SLC22 transporters based on the PiPT structure to surmise the structural basis for substrate binding and charge selectivity in this important family. The PiPT structure demonstrates and expands on principles of substrate transport by the MFS transporters and illuminates principles of phosphate uptake in particular.


Asunto(s)
Basidiomycota/química , Células Eucariotas/química , Proteínas de Transporte de Fosfato/química , Sitios de Unión , Cristalografía por Rayos X , Humanos , Modelos Biológicos , Modelos Moleculares , Proteínas de Transporte de Fosfato/metabolismo , Fosfatos/metabolismo , Conformación Proteica , Protones , Relación Estructura-Actividad
9.
Curr Oncol ; 24(2): 124-128, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28490927

RESUMEN

Meaningful performance measures are an important part of the toolkit for health system improvement. The Canadian Partnership Against Cancer has been reporting on pan-Canadian cancer system performance indicators since 2009-work that has led to the availability of standardized measures that can help to shed light on the extent of variation and opportunities for quality improvement across the country. Those measures include a core set of system indicators ranging from prevention and screening, through diagnosis and treatment, to survivorship and end-of-life care. Key indicators were calculated and graphed, showing the range from worst to best result for the provinces and territories included in the data. There were often significant differences in cancer system performance between provinces and territories. For example, smoking prevalence rates ranged from 14% to 62%. The 90th percentile wait times from an abnormal breast screen to resolution (without biopsy) ranged from 4 weeks to 8 weeks. The percentage of breast cancer resections that used breast-conserving surgery rather than mastectomy ranged from 38% to 75%. Clinical trial participation rates for adults ranged from 0.2% to 6.6%. Variations in performance indicators between Canadian jurisdictions suggest potential differences in the planning and delivery of cancer control services and in clinical practice patterns and patient outcomes. Understanding sources of variation can help to identify opportunities for improvements in the quality and outcomes of cancer control service delivery in each province and territory.

10.
Curr Oncol ; 24(3): 201-206, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28680281

RESUMEN

Value-based care, which balances high-quality care with the most efficient use of resources, has been considered the next frontier in cancer care and a means to maintain health system sustainability. Created to promote value-based care, Choosing Wisely Canada-modelled after Choosing Wisely in the United States-is a national clinician-driven campaign to identify unnecessary or harmful services that are frequently used in Canada. As part of the campaign, national medical societies have developed recommendations for tests and treatments that clinicians and patients should question. Here, we present baseline indicator findings about current practice patterns associated with 7 cancer-related recommendations from Choosing Wisely Canada and about the effects of those practices on patients and the health care system. Indicator findings point to substantial variations in cancer system performance between Canadian jurisdictions, most notably for breast cancer screening practices, treatment practices for men with low-risk localized prostate cancer, and radiation therapy practices for early-stage breast cancer and bone metastases. Extrapolating indicator findings to the entire country, it was estimated that 740,000 breast and cervical cancer screening tests were performed outside of the recommended age ranges, and within 1 year of diagnosis, 17,000 patients received treatments that could be low-value. A 15% reduction in the use of the 7 screening and treatment practices examined could lead to multiple benefits for patients and the health care system: 9000 false-positive results and 3000 treatments and related side effects could be avoided, and 4500 hours of linear accelerator capacity could be freed up each year. Interjurisdictional performance variations suggest potential differences in clinical practice patterns in the planning and delivery of cancer control services, and in some cases, in disease management outcomes. Although the cancer screening and treatment practices described might be unnecessary for some patients, it is important to realize that they could, in fact, be necessary for other patients. Further research into appropriate rates of use could help to determine how much cancer care represents overuse of practices that are not supported by evidence or underuse of practices that are supported by evidence.

11.
Curr Oncol ; 24(4): 256-261, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28874894

RESUMEN

Acute care hospitals have a role in managing the health care needs of people affected by cancer when they are at the end of life. However, there is a need to provide end-of-life care in other settings, including at home or in hospice, when such settings are more appropriate. Using data from 9 provinces, we examined indicators that describe the current landscape of acute care hospital use at the end of life for patients who died of cancer in hospital in Canada. Interprovincial variation was observed in acute care hospital deaths, length of stay in hospital, readmission to hospital, and intensive care unit use at the end of life. High rates of acute care hospital use near the end of life might suggest that community and home-based end-of-life care might not be suiting patient needs.

12.
Curr Oncol ; 23(3): 201-3, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27330349

RESUMEN

Evidence shows that continued smoking by cancer patients leads to adverse treatment outcomes and affects survival. Smoking diminishes treatment effectiveness, exacerbates side effects, and increases the risk of developing additional complications. Patients who continue to smoke also have a higher risk of developing a second primary cancer or experiencing a cancer recurrence, both of which ultimately contribute to poorer quality of life and poorer survival. Here, we present a snapshot of smoking behaviours of current cancer patients compared with the non-cancer patient population in Canada. Minimal differences in smoking behaviours were noted between current cancer patients and the rest of the population. Based on 2011-2014 data from the Canadian Community Health Survey, 1 in 5 current cancer patients (20.1%) reported daily or occasional smoking. That estimate is comparable to findings in the surveyed non-cancer patient population, of whom 19.3% reported smoking daily or occasionally. Slightly more male cancer patients than female cancer patients identified as current smokers. A similar distribution was observed in the non-cancer patient population. There is an urgent need across Canada to better support cancer patients in quitting smoking. As a result, the quality of patient care will improve, as will cancer treatment and survival outcomes, and quality of life for these patients.

13.
Curr Oncol ; 23(5): 351-355, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27803600

RESUMEN

BACKGROUND: As part of Choosing Wisely Canada (a national campaign to encourage patient-provider conversations about unnecessary medical tests, treatments, and procedures), a list of ten oncology practices that could be low-value in some instances was developed. Of those practices, two were specific to radiation therapy (rt): conventional fractionation as part of breast-conserving therapy (bct) for women with early-stage breast cancer, and multifraction radiation for palliation of uncomplicated painful bone metastases. Here, we report baseline findings for the current utilization rates of those two rt practices in Canada. RESULTS: The use of conventional fractionation as part of bct varied substantially from province to province. Of women 50 years of age and older, between 8.8% (Alberta) and 36.5% (Saskatchewan) received radiation in 25 fractions (excluding boost irradiation) as part of bct. The use of hypofractionated rt (that is, 16 fractions excluding boost irradiation)-a preferred approach for many patients-was more common in all 6 reporting provinces, ranging from 43.2% in Saskatchewan to 94.7% in Prince Edward Island. The use of multifraction rt for palliation of bone metastases also varied from province to province, ranging from 40.3% in British Columbia to 69.0% in Saskatchewan. The most common number of fractions delivered to bone metastases was 1, at 50.2%; the second most common numbers were 2-5 fractions, at 41.7%. CONCLUSIONS: Understanding variation in the use of potentially low-value rt practices can help to inform future strategies to promote higher-value care, which balances high-quality care with the efficient use of limited system resources. Further work is needed to understand the factors contributing to the interprovincial variation observed and to develop benchmarks for the appropriate rate of use of these rt practices.

14.
Curr Oncol ; 23(1): 56-9, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26966405

RESUMEN

BACKGROUND: Many prostate cancers (pcas) are indolent and, if left untreated, are unlikely to cause death or morbidity in a man's lifetime. As a result of testing for prostate-specific antigen, more such cases are being identified, leading to concerns about "overdiagnosis" and consequent overtreatment of pca. To mitigate the risks associated with overtreatment (that is, invasive therapies that might cause harm to the patient without tangible benefit), approaches such as active surveillance are now preferred for many men with low-risk localized pca (specifically, T1/2a, prostate-specific antigen ≤ 10 ng/mL, and Gleason score ≤ 6). Here, we report on patterns of care and treatment trends for men with localized low-risk pca. RESULTS: The provinces varied substantially with respect to the types of primary treatment received by men with localized low-risk pca. From 2010 to 2013, many men had no record of surgical or radiation treatment within 1 year of diagnosis-a proxy for active surveillance; the proportion ranged from 53.3% in Nova Scotia to 80.8% in New Brunswick. Among men who did receive primary treatment, the use of radical prostatectomy ranged from 12.0% in New Brunswick to 35.9% in Nova Scotia. The use of radiation therapy (external-beam radiation therapy or brachytherapy) ranged from 4.1% in Newfoundland and Labrador to 17.6% in Alberta. Treatment trends over time suggest an increase in the use of active surveillance. The proportion of men with low-risk pca and no record of surgical or radiation treatment rose to 69.9% in 2013 from 46.1% in 2010 for all provinces combined. CONCLUSIONS: The provinces varied substantially with respect to patterns of care for localized low-risk pca. Treatment trends over time suggest an increasing use of active surveillance. Those findings can further the discussion about the complex care associated with pca and identify opportunities for improvement in clinical practice.

15.
Mol Microbiol ; 91(2): 275-99, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24224966

RESUMEN

Filamentous fungi are powerful producers of hydrolytic enzymes for the deconstruction of plant cell wall polysaccharides. However, the central question of how these sugars are perceived in the context of the complex cell wall matrix remains largely elusive. To address this question in a systematic fashion we performed an extensive comparative systems analysis of how the model filamentous fungus Neurospora crassa responds to the three main cell wall polysaccharides: pectin, hemicellulose and cellulose. We found the pectic response to be largely independent of the cellulolytic one with some overlap to hemicellulose, and in its extent surprisingly high, suggesting advantages for the fungus beyond being a mere carbon source. Our approach furthermore allowed us to identify carbon source-specific adaptations, such as the induction of the unfolded protein response on cellulose, and a commonly induced set of 29 genes likely involved in carbon scouting. Moreover, by hierarchical clustering we generated a coexpression matrix useful for the discovery of new components involved in polysaccharide utilization. This is exemplified by the identification of lat-1, which we demonstrate to encode for the physiologically relevant arabinose transporter in Neurospora. The analyses presented here are an important step towards understanding fungal degradation processes of complex biomass.


Asunto(s)
Adaptación Fisiológica , Carbono/metabolismo , Pared Celular/metabolismo , Neurospora crassa/metabolismo , Polisacáridos/metabolismo , Arabinosa/metabolismo , Biomasa , Celulosa/metabolismo , Regulación Fúngica de la Expresión Génica , Genes Fúngicos , Neurospora crassa/genética , Pectinas/metabolismo , Desplegamiento Proteico , Proteómica
16.
Br J Dermatol ; 173 Suppl 2: 10-6, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26207659

RESUMEN

BACKGROUND: In 2005, the L'Oréal Institute for hair and skin research carried out a multiethnic study to investigate hair breakage in women residing in the U.S.A. In this study it was reported that a large percentage (96%) of the African-American respondents experience breakage. A combination of structural differences and grooming-induced stresses seem to contribute to the higher breakage incidence in the African-American group as the chemical composition of African-American hair is not significantly different from other ethnic groups. Some authors have proposed that the repeated elongation, torsion and flexion actions may affect the components of the hair fibre. However, considering the different properties of cuticle and cortex, one would expect a different wearing mechanism of each, leading to the ultimate failure of hair. Knowing in detail how each part of the structure fails can potentially lead to better ways to protect the hair from physical insults. OBJECTIVE: To investigate crack propagation and fracture mechanisms in African-American hair. METHODS: Virgin hair of excellent quality was collected, with informed consent, from a female African-American volunteer. A series of controlled mechanical stresses was applied to 10-mm hair sections using a high-resolution mechanical stage (20 mN) up to the fracture of the fibre. The surface was monitored using scanning electron microscopy imaging during the stress application. X-ray tomographic microscopy images were acquired and quantified to detect changes in energy absorption as a function of applied stress that could be linked to increase in crack density. RESULTS: Analysis of the mechanical response of hair combined with the two imaging techniques led us to propose the following mechanism of hair breakage: cuticle sliding; failure of the cuticle-cortex interface; nucleation of intercellular cracks and growth of cracks at the cuticle-cortex junction; and propagation of intercellular cracks towards the surface of the hair and final breakage when these cracks merge at the cuticular junction. CONCLUSIONS: The combination of scanning electron microscopy and X-ray tomography provided new information about the fracture of hair. Mechanical damage from grooming and some environmental factors accumulate in hair creating internal cracks that eventually result in breakage at unpredictable sites and therefore a continuous care regimen for the hair throughout the life cycle of the fibres is recommended.


Asunto(s)
Cabello/fisiología , Negro o Afroamericano/etnología , Femenino , Cabello/ultraestructura , Voluntarios Sanos , Humanos , Imagenología Tridimensional , Microscopía Electrónica de Rastreo , Estrés Fisiológico/fisiología , Sincrotrones , Resistencia a la Tracción , Tomografía Computarizada por Rayos X
17.
Curr Oncol ; 22(6): 427-9, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26715876

RESUMEN

In general, guideline-recommended treatment options for men with low-risk prostate cancer (pca) include active surveillance, radical prostatectomy, and external-beam radiation therapy or brachytherapy. Because of the concern about overdiagnosis and consequent overtreatment of pca, patients with low-risk disease are increasingly being managed with active surveillance. Using data from six provincial cancer registries, we examined treatment patterns within a year of a diagnosis of localized low-risk pca, and we assessed differences by age. Of patients diagnosed in 2010 in four of the six reporting provinces, most received surgery or radiation therapy within 1 year of diagnosis. Depending on the province, either surgery or radiation therapy was the most commonly used primary treatment. In the other two provinces, most patients had no record of treatment within a year of diagnosis. Examining treatment patterns by age demonstrated a lesser likelihood of receiving surgery or radiation therapy within 1 year of diagnosis among men more than 75 years of age than among men 75 years of age or younger (no record of treatment in 69.1% and 46.3% respectively). In conclusion, we observed interprovincial and age-specific variations in the patterns of care for men with low-risk pca. The findings presented in this report are intended to identify opportunities for improvement in clinical practice that could lead to improved care and experience.

18.
Curr Oncol ; 22(5): 361-4, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26628869

RESUMEN

BACKGROUND: Access to cancer care is a significant concern for Canadians. Prolonged delays between cancer diagnosis and treatment have been associated with anxiety, stress, and perceived powerlessness for patients and their family members. Longer wait times can also be associated with poorer prognosis, although the evidence is inconclusive. Here, we report national wait times for radiation therapy and surgery for localized prostate cancer (pca) and the effect of wait time on patient perceptions of their care. RESULTS: Treatment wait times showed substantial interprovincial variation. The longest 90th percentile wait times for radiation therapy and surgery were, respectively, 40 days and 105 days. In all provinces, waits for radiation therapy were longer for pca patients than for patients with breast, colorectal, or lung cancer. In the focus groups and interviews conducted with 47 men treated for pca, many participants did not perceive that wait times for treatment were prolonged. Those who experienced delays between diagnosis and treatment voiced issues with a lack of communication about when they would receive treatment and a lack of support or information to make an informed decision about treatment. Minimizing treatment delays was an aspect of the cancer journey that participants would like to change because of the stress it caused. CONCLUSIONS: Although wait time statistics are useful, a review of cancer control in Canada cannot be considered complete unless an effort is made to give voice to the experiences of individuals with cancer. The findings presented here are intended to provide a snapshot of national care delivery for localized pca and to identify opportunities for improvement in clinical practice.

19.
Curr Oncol ; 22(4): 297-302, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26300668

RESUMEN

In Canada, self-reported data from the Canadian Community Health Survey 2008 and 2012 provide an opportunity to examine overall utilization of breast, cervical, and colorectal cancer screening tests for both programmatic and opportunistic screening. Among women 50-74 years of age, utilization of screening mammography was stable (62.0% in 2008 and 63.0% in 2012). Pap test utilization for women 25-69 years of age remained high and stable across Canada in 2008 and 2012 (78.9% in 2012). The percentage of individuals 50-74 years of age who reporting having at least 1 fecal test within the preceding 2 years increased in 2012 (to 23.0% from 16.9% in 2008), but remains low. Stable rates of screening mammography utilization (about 30%) were reported in 2008 and 2012 among women 40-49 years of age, a group for which population-based screening is not recommended. Although declining over time, cervical cancer screening rates were high for women less than 25 years of age (for whom screening is not recommended). Interestingly, an increased percentage of women 70-74 years of age reported having a Pap test. In 2012, a smaller percentage of women 50-69 years of age reported having no screening test (5.9% vs. 8.5% in 2008), and more women reported having the three types of cancer screening tests (19.0% vs. 13.2%). Efforts to encourage use of screening within the recommended average-risk age groups are needed, and education for stakeholders about the possible harms of screening outside those age groups has to continue.

20.
Physiol Behav ; 277: 114501, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38387846

RESUMEN

Salivary alpha-amylase (sAA) has gained popularity as an easily collected biomarker for sympathetic nervous system activation, and research has shown increases in sAA after completing experimental stress tasks in certain groups. However, recent work suggests that salivary cortisol, another stress biomarker, is suppressed after a speech task among experimentally induced exclusion in young women. The present analysis investigated the sAA response in biologically female undergraduates (n=31) who completed a game of Cyberball and then a speech anticipation task. Results showed that women in the social exclusion experimental group had a greater decrease in sAA compared to young women in the inclusion group after the speech task. Results of this study provide support for stress response suppression in women who have experienced social exclusion. The present findings provide pilot evidence for future, larger studies to advance the tend-and-befriend theory.


Asunto(s)
alfa-Amilasas Salivales , Humanos , Femenino , Habla/fisiología , Estrés Psicológico , Saliva , Hidrocortisona , Biomarcadores
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