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1.
JDR Clin Trans Res ; : 23800844231199385, 2023 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-37775967

RESUMEN

INTRODUCTION: Globally, the number of people living with dementia (PLwD) is projected to increase substantially. Dentists will encounter an increasing number of PLwD retaining natural teeth who need dental care. Dental treatment planning can be complex for PLwD as both oral diseases and dental treatment can be detrimental to patients' oral and social function and comfort. In addition, patients may lack the capacity to make decisions about their treatment, posing further challenges for dentists. OBJECTIVE: This study aimed to explore dentists' approach to treatment decision-making with or for PLwD. METHODS: Semistructured one-to-one interviews were completed with 22 dentists between April 2020 and March 2021. Data generation and analysis followed the principles of constructivist grounded theory with data being collected and analyzed simultaneously using a maximum variation sample. Interviews were recorded, transcribed verbatim, and then analyzed, leading to a theoretical understanding of how dentists approach treatment decisions for PLwD. RESULTS: Four data categories describe dentists' approaches to treatment decision-making for PLwD. Dentists sought to provide individualized care for PLwD. However, they described planning care based on risk-benefit analyses that primarily considered biomedical factors and generic assumptions. There was an underemphasis on the psychological or social implications of dental care or its delivery. Furthermore, while some dentists attempted to involve patients in treatment decisions, they reported fewer attempts to identify the views and preferences of PLwD identified as lacking decisional capacity. In this scenario, dentists reported leading the decision-making process with little regard for patients' known or identified preferences and minimal involvement of PLwD's family. CONCLUSIONS: Dentists acknowledge the complexity in treatment decision-making for PLwD yet focused heavily on biomedical considerations, with an underemphasis on individuals' preferences and autonomy. Considering psychosocial aspects of care alongside biomedical factors is essential to support holistic person-centered care for this growing patient cohort. KNOWLEDGE TRANSFER STATEMENT: This study highlighted that dentists may only be considering biomedical aspects of care when considering what treatment is appropriate for people living with dementia. When making or supporting treatment decisions, dentists should explore patients' preferences and actively consider relevant psychosocial factors. These can be actively identified through considered discussions with patients as well as their family members. Gathering this information should support more person-centered and value-concordant decision-making for people living with dementia.

2.
JDR Clin Trans Res ; 8(4): 337-348, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-36032014

RESUMEN

AIMS: To discover whether dental visiting behavior can be understood as a dichotomy of planned versus problem based, or whether there were a range of different types of understanding and patient behavior, recognizable as patterns of dental visiting behavior. METHODS: Secondary analysis drawing on 2 qualitative studies of patients' accounts of dental attendance and oral health, with 1) opportunistic interviews with people attending urgent dental care services (n = 43; including 19 with follow-up) and 2) home-based, in-depth interviews with people attending a dental practice with a mixture of improved or deteriorated/poor periodontal health (n = 25). RESULTS: Four distinguishable patterns of dental visiting were identified in patients' accounts: Accepting and Active Monitoring, as well as Ambivalent and Active Problem-based dental visiting behavior. Individuals' patterns were relatively stable over time but could shift at turning points. Accepting Monitors were characterized as accepting dentists' recommendations and dental practice policies relating to oral health and visits, whereas Active Monitors were more independent in judging how often to attend for preventive appointments, while still valuing anticipatory care. Ambivalent Problem-based visitors placed a relatively low value on anticipatory care for oral health maintenance and drifted into lapsed attendance, in part because of service-related factors. This contrasted with Active Problem-based visitors, for whom using services only in an emergency was a conscious decision, with low value placed on anticipatory care. CONCLUSION: This article demonstrates the dynamic nature of patterns of dental visiting where the dental system itself is partly instrumental in shaping patterns of utilization in an ecological way. Thus, service-related factors tend to combine with patients' behavior in expanding inequalities. This illuminates the reasons why risk-based recalls are challenging to implement as a dental policy. KNOWLEDGE TRANSFER STATEMENT: The results of this analysis can be used by clinicians and policymakers to inform policy around supporting uptake of preventive health care visits, contributing in particular to understanding how risk-based preventive visiting policies may be better adapted to patients' understanding of the purpose of visits, taking into account that this is in part shaped by service-related factors in an ecological way, arising from patients' and dental teams' expectations.


Asunto(s)
Salud Bucal , Servicios Preventivos de Salud , Humanos , Investigación Cualitativa
3.
JDR Clin Trans Res ; 7(2): 215-217, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-33618559

RESUMEN

In qualitative research, the researcher is the research instrument. Therefore, a qualitative researcher who is also a clinician must consider how their dual position informs participant consent, data collection, and analysis. This reflexivity is essential in research design to effectively respond to ethical questions around role, authenticity, trust, and transparency around disclosing their clinician status to participants.


Asunto(s)
Investigación Dental , Investigadores , Humanos , Investigación Cualitativa , Confianza
4.
JDR Clin Trans Res ; : 23800844211056241, 2021 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-34844457

RESUMEN

INTRODUCTION: In any health system, choices must be made about the allocation of resources (budget), which are often scarce. Economics has defined frameworks to aid resource allocation, and program budgeting marginal analysis (PBMA) is one such framework. In principle, patient and public values can be incorporated into these frameworks, using techniques such as willingness to pay (WTP). However, this has not been done before, and few formal resource allocation processes have been undertaken in dentistry. This study aimed to undertake a PBMA with embedded WTP values in a national dental setting. METHODS: The PBMA process was undertaken by a panel of participant-researchers representing commissioners, dentists, dental public health staff, and academics. The panel reviewed current allocations and generated a set of weighted criteria to evaluate services against. Services to be considered for removal and investment were determined by the panel and wider discussion and then scored against the criteria. Values from a nationally representative WTP survey of the public contributed to the scores for interventions. Final decisions on removal and investment were taken after panel discussion using individual anonymous electronic voting. RESULTS: The PBMA process resulted in recommendations to invest in new program components to improve access to general dentists, care home dentistry, and extra support for dental public health input into local government decisions. Disinvestments were recommended in orthodontics and to remove routine scaling and polishing of teeth. DISCUSSION: The PBMA process was successful in raising awareness of resource allocation issues. Implementation of findings will depend on the ability of decision makers to find ways of operationalizing the decisions. The process illustrates practical aspects of the process that future dental PBMAs could learn from. KNOWLEDGE TRANSFER STATEMENT: This study illustrates a framework for resource allocation in dental health services and will aid decision makers in implementing their own resource allocation systems.

5.
6.
Anaesthesia ; 74(6): 819, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-31063203

Asunto(s)
Aluminio
7.
J Public Health (Oxf) ; 41(1): e103-e108, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-29924348

RESUMEN

BACKGROUND: Inequalities in dental decay in young children persist, resulting in high admission rates for general anaesthetics for tooth extractions. Health visitors have the potential to improve dental attendance and oral health in families least likely to engage with dental services. There is little evidence on health visitor views on this. METHODS: Semi-structured interviews were conducted with a purposive sample of 17 health visitors working in both affluent and deprived areas in a single UK city. Interviews were audio recorded, transcribed, anonymized and analysed following a constructivist grounded theory approach. RESULTS: Knowledge of oral health was high and health visitors requested oral health education specific to the communities they worked in. Health visitors reported effective, formal referral processes to other health services but not to primary NHS dental services even when dealing with infants in pain. Health visitors interviewed were largely unaware of specific NHS dental services which reduce barriers to dental care including interpreting services and dental services for children with additional needs. CONCLUSIONS: Health visitors interviewed were knowledgeable and enthusiastic about oral health but not about dental services. Inadequate links with NHS dental services may limit their effectiveness in oral health improvement and this needs to be addressed.


Asunto(s)
Caries Dental/psicología , Conocimientos, Actitudes y Práctica en Salud , Salud Bucal , Adulto , Niño , Preescolar , Femenino , Promoción de la Salud , Disparidades en el Estado de Salud , Humanos , Entrevistas como Asunto , Persona de Mediana Edad , Investigación Cualitativa , Medicina Estatal , Reino Unido
8.
J Public Health (Oxf) ; 40(4): e578-e585, 2018 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-29726998

RESUMEN

Background: Priority setting is necessary where competing demands exceed the finite resources available. The aim of the study was to develop and test a prioritization framework based upon programme budgeting and marginal analysis (PBMA) as a tool to assist National Health Service (NHS) commissioners in their management of resources for local NHS dental services. Methods: Twenty-seven stakeholders (5 dentists, 8 commissioners and 14 patients) participated in a case-study based in a former NHS commissioning organization in the north of England. Stakeholders modified local decision-making criteria and applied them to a number of different scenarios. Results: The majority of financial resources for NHS dental services in the commissioning organization studied were allocated to primary care dental practitioners' contracts in perpetuity, potentially constraining commissioners' abilities to shift resources. Compiling the programme budget was successful, but organizational flux and difficulties engaging local NHS commissioners significantly impacted upon the marginal analysis phase. Conclusions: NHS dental practitioners' contracts resemble budget-silos which do not facilitate local resource reallocation. 'Context-specific' factors significantly challenged the successful implementation and impact of PBMA. A local PBMA champion embedded within commissioning organizations should be considered. Participants found visual depiction of the cost-value ratio helpful during their initial priority setting deliberations.


Asunto(s)
Presupuestos/organización & administración , Atención Odontológica/organización & administración , Prioridades en Salud/organización & administración , Medicina Estatal/organización & administración , Adulto , Comités Consultivos , Anciano , Anciano de 80 o más Años , Presupuestos/métodos , Análisis Costo-Beneficio/métodos , Toma de Decisiones en la Organización , Atención Odontológica/economía , Atención Odontológica/métodos , Inglaterra , Femenino , Prioridades en Salud/economía , Humanos , Masculino , Persona de Mediana Edad , Medicina Estatal/economía , Adulto Joven
9.
BMC Cancer ; 18(1): 1, 2018 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-29291726

RESUMEN

BACKGROUND: Head and neck cancer squamous cell carcinoma (HNSSC) patients report substantial rates of clinically significant depression and/or anxiety, with dysphagia being a predictor of distress and poorer quality of life. Evidence-based dysphagia interventions largely focus on the remediation of physical impairment. This feasibility study evaluates an intervention which simultaneously uses a psychological therapy approach combined with swallowing impairment rehabilitation. METHODS: This prospective single cohort mixed-methods study, recruited HNSCC patients with dysphagia, from two institutions. The intervention combined Cognitive Behavioural Therapy with swallowing therapy (CB-EST), was individually tailored, for up to 10 sessions and delivered by a speech and language therapist. Primary acceptability and feasibility measures included recruitment and retention rates, data completion, intervention fidelity and the responsiveness of candidate outcome measures. Measures included a swallowing questionnaire (MDADI), EORTC-QLQH&N35, dietary restrictions scale, fatigue and function scales and the Hospital Anxiety and Depression Scale (HADS), administered pre-, post-CB-EST with three month follow-up and analysed using repeated measures ANOVA. Qualitative interviews were conducted to evaluate intervention processes. RESULTS: A total of 30/43 (70%) eligible patients agreed to participate and 25 completed the intervention. 84% were male, mean age 59 yrs. Patients were between 1 and 60 months (median 4) post-cancer treatment. All patients had advanced stage disease, treated with surgery and radiotherapy (38%) or primary chemoradiotherapy (62%). Pre to post CB-EST data showed improvements in MDADI scores (p = 0.002), EORTC-QLQH&N35 (p = 0.006), dietary scale (p < 0.0001), fatigue (p = 0.002) but no change in function scales or HADS. Barriers to recruitment were the ability to attend regular appointments and patient suitability or openness to a psychological-based intervention. CONCLUSIONS: CB-EST is a complex and novel intervention, addressing the emotional, behavioural and cognitive components of dysphagia alongside physical impairment. Preliminary results are promising. Further research is required to evaluate efficacy and effectiveness.


Asunto(s)
Terapia Cognitivo-Conductual/métodos , Terapia Combinada/efectos adversos , Trastornos de Deglución/rehabilitación , Trastornos de Deglución/terapia , Terapia por Ejercicio/métodos , Neoplasias de Cabeza y Cuello/terapia , Anciano , Ansiedad/etiología , Ansiedad/terapia , Trastornos de Deglución/etiología , Depresión/etiología , Depresión/terapia , Estudios de Factibilidad , Femenino , Estudios de Seguimiento , Neoplasias de Cabeza y Cuello/complicaciones , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos
10.
JDR Clin Trans Res ; 2(1): 48-57, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28879244

RESUMEN

Persistent orofacial pain is relatively common and known to have an adverse effect on quality of life. Previous studies suggest that the current care pathway may be problematic, but it is not well understood which health services patients access and what their experience is. The aim of this study was to explore care pathways and their impact from the perspective of patients. Qualitative interviews were conducted with a maximum variation sample of patients recruited from primary (community based) and secondary (specialist hospital based) care in the United Kingdom. Questions focused on the stages in their pathway and the impact of the care that they had received. Interviews were digitally recorded and transcribed verbatim, and analysis followed principles of the constant comparative method. NVivo 10 was used to help organize and analyze data. Twenty-two patients were interviewed at baseline, and 18 took part in a second interview at 12 mo. Three main themes emerged from the data: the "fluidity of the care pathway," in which patients described moving among health care providers in attempts to have their pain diagnosed and managed, occurring alongside a "failure to progress," where despite multiple appointments, patients described frustration at delays in obtaining a diagnosis and effective treatment for their pain. Throughout their care pathways, patients described the "effects of unmanaged pain," where the longer the pain went unmanaged, the greater its potential to negatively affect their lives. Findings of this study suggest that the current care pathway is inefficient and fails to meet patient needs. Future work needs to focus on working with stakeholder groups to redesign patient-centered care pathways. Knowledge Transfer Statement: Data from qualitative interviews conducted with patients with persistent orofacial pain suggest significant problems with the existing care pathway, consisting of delays to diagnosis, treatment, and referral. Patients describing their struggle to progress through the current care pathway highlighted the difficulties occurring while living with orofacial pain. This study suggests a need for a revised care pathway, which better meets the needs of people with persistent orofacial pain.

12.
Ann Pharm Fr ; 75(4): 245-256, 2017 Jul.
Artículo en Francés | MEDLINE | ID: mdl-28576261

RESUMEN

We reviewed the three reference toxicokinetic studies commonly used to suggest innocuity of aluminum (Al)-based adjuvants. A single experimental study was carried out using isotopic 26Al (Flarend et al., 1997). This study ignored adjuvant cell capture. It was conducted over a short period of time (28 days) and used only two rabbits per adjuvant. At the endpoint, Al retention was 78% for aluminum phosphate and 94% for aluminum hydroxide, both results being incompatible with quick elimination of vaccine-derived Al in urines. Tissue distribution analysis omitted three important retention sites: the injected muscle, the draining lymph node and bone. Two theoretical studies have evaluated the potential risk of vaccine Al in infants, by reference to the oral Minimal Risk Level (MRL) extrapolated from animal studies. Keith et al., 2002 used a too high MRL (2mg/kg/d), an erroneous model of 100% immediate absorption of vaccine Al, and did not consider renal and blood-brain barrier immaturity. Mitkus et al. (2011) only considered absorbed Al, with erroneous calculations of absorption duration. They ignored particulate Al captured by immune cells, which play a role in systemic diffusion and the neuro-inflammatory potential of the adjuvant. MRL they used was both inappropriate (oral Al vs injected adjuvant) and far too high (1mg/kg/d) with regard to experimental studies of Al-induced memory and behavioral changes. Both paucity and serious weaknesses of these studies strongly suggest that novel experimental studies of Al adjuvants toxicokinetics should be performed on the long-term, including post-natal and adult exposures, to ensure innocuity and restore population confidence in Al-containing vaccines.


Asunto(s)
Adyuvantes Inmunológicos/farmacocinética , Hidróxido de Aluminio/farmacocinética , Aluminio/farmacocinética , Compuestos de Aluminio , Animales , Humanos , Fosfatos , Conejos , Valores de Referencia , Distribución Tisular , Toxicocinética , Vacunas
13.
BMJ Open ; 6(7): e012559, 2016 07 21.
Artículo en Inglés | MEDLINE | ID: mdl-27443554

RESUMEN

OBJECTIVE: To critically examine the process of multidisciplinary team (MDT) decision-making with a particular focus on patient involvement. DESIGN: Ethnographic study using direct non-participant observation of 35 MDT meetings and 37 MDT clinics, informal interviews and formal, semistructured interviews with 20 patients and 9 MDT staff members. SETTING: Three head and neck cancer centres in the north of England. PARTICIPANTS: Patients with a diagnosis of new or recurrent head and neck cancer and staff members who attend the head and neck cancer MDT. RESULTS: Individual members of the MDT often have a clear view of which treatment they consider to be 'best' in any clinical situation. When disagreement occurs, the MDT has to manage how it presents this difference of opinion to the patient. First, this is because the MDT members recognise that the clinician selected to present the treatment choice to the patient may 'frame' their description of the treatment options to fit their own view of best. Second, many MDT members feel that any disagreement and difference of opinion in the MDT meeting should be concealed from the patient. This leads to much of the work of decision-making occurring in the MDT meeting, thus excluding the patient. MDT members seek to counteract this by introducing increasing amounts of information about the patient into the MDT meeting, thus creating an 'evidential patient'. Often, only highly selected or very limited information of this type can be available or known and it can easily be selectively reported in order to steer the discussion in a particular direction. CONCLUSIONS: The process of MDT decision-making presents significant barriers to effective patient involvement. If patients are to be effectively involved in cancer decision-making, the process of MDT decision-making needs substantial review.


Asunto(s)
Conducta Cooperativa , Toma de Decisiones , Neoplasias de Cabeza y Cuello/terapia , Grupo de Atención al Paciente/organización & administración , Participación del Paciente/métodos , Adulto , Anciano , Manejo de la Enfermedad , Femenino , Neoplasias de Cabeza y Cuello/psicología , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Investigación Cualitativa
14.
J Dent Res ; 95(10): 1147-54, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27154734

RESUMEN

Few data are available on the healthcare costs of those suffering from persistent orofacial pain (POFP). This cohort and cost analysis study examined the direct costs of POFP from the perspective of the healthcare provider (specifically, the UK National Health Service) in 2012 pounds sterling and sought to identify whether dichotomized (high, IIb to IV; low, 0 to IIa) graded chronic pain scale (GCPS) status is predictive of the total cost of healthcare over the last 6 mo. The healthcare utilization data of 198 patients with POFP were collected using a structured interview and a validated "use of services and productivity" questionnaire. Unit costs were used with these utilization data to calculate direct healthcare costs in 3 categories: consultation, medication, and appliances and interventions. Consultation costs were a significant proportion of cumulative healthcare cost (P < 0.001). Dichotomized GCPS status was predictive of increased healthcare cost over the last 6 mo, accounting for an average increase of £366 (95% confidence interval, 135 to 598; P < 0.01) when moving from a low GCPS status to a high GCPS status. Given the predictive capability of dichotomized GCPS status and the success of stratified models of care for other persistent pain conditions, dichotomized GCPS status may offer an opportunity to help determine stratification of care for patients with POFP.


Asunto(s)
Dolor Crónico/economía , Dolor Facial/economía , Costos de la Atención en Salud , Aceptación de la Atención de Salud , Adulto , Anciano , Femenino , Investigación sobre Servicios de Salud , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Calidad de Vida , Derivación y Consulta/economía , Medicina Estatal/economía , Encuestas y Cuestionarios , Reino Unido
15.
Morphologie ; 100(329): 51-5, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26922890

RESUMEN

We are living in the 'aluminium age'. Human exposure to aluminium is inevitable and, perhaps, inestimable. Aluminium's free metal cation, Alaq(3+), is highly biologically reactive and biologically available aluminium is non-essential and essentially toxic. Biologically reactive aluminium is present throughout the human body and while, rarely, it can be acutely toxic, much less is understood about chronic aluminium intoxication. Herein the question is asked as to how to diagnose aluminium toxicity in an individual. While there are as yet, no unequivocal answers to this problem, there are procedures to follow to ascertain the nature of human exposure to aluminium. It is also important to recognise critical factors in exposure regimes and specifically that not all forms of aluminium are toxicologically equivalent and not all routes of exposure are equivalent in their delivery of aluminium to target sites. To ascertain if Alzheimer's disease is a symptom of chronic aluminium intoxication over decades or breast cancer is aggravated by the topical application of an aluminium salt or if autism could result from an immune cascade initiated by an aluminium adjuvant requires that each of these is considered independently and in the light of the most up to date scientific evidence. The aluminium age has taught us that there are no inevitabilities where chronic aluminium toxicity is concerned though there are clear possibilities and these require proving or discounting but not simply ignored.


Asunto(s)
Adyuvantes Inmunológicos/efectos adversos , Compuestos de Aluminio/farmacocinética , Compuestos de Aluminio/toxicidad , Enfermedad de Alzheimer/inducido químicamente , Neoplasias de la Mama/inducido químicamente , Exposición a Riesgos Ambientales/efectos adversos , Neuronas/efectos de los fármacos , Compuestos de Aluminio/efectos adversos , Antitranspirantes/efectos adversos , Antitranspirantes/química , Disponibilidad Biológica , Encéfalo/efectos de los fármacos , Humanos , Factores de Riesgo , Vacunas/efectos adversos
16.
Reprod Toxicol ; 50: 43-8, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25461904

RESUMEN

A deterioration of human semen quality has been observed over recent decades. A possible explanation could be an increased exposure to environmental pollutants, including aluminum. Our aim was to measure the aluminum concentration in the semen of 62 patients and to carry out a preliminary evaluation on its impact on specific semen parameters. For each patient, semen analyses were performed according to WHO guidelines. A graphite furnace atomic absorption spectrometry method was used to determine semen aluminum concentration. A cytological analysis using an aluminum-specific fluor, lumogallion, was also performed. The mean aluminum concentration in human semen was 339 µg/L. Patients with oligozoospermia had a statistically higher aluminum concentration than others. No significant difference was observed for other semen parameters. Cytological analysis showed the presence of aluminum in spermatozoa. This study provided unequivocal evidence of high concentrations of aluminum in human semen and suggested possible implications for spermatogenesis and sperm count.


Asunto(s)
Aluminio/análisis , Semen/química , Adulto , Humanos , Masculino , Microscopía Fluorescente , Oligospermia/metabolismo
17.
J R Soc Interface ; 11(95): 20140165, 2014 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-24671940

RESUMEN

For decades, a link between increased levels of iron and areas of Alzheimer's disease (AD) pathology has been recognized, including AD lesions comprised of the peptide ß-amyloid (Aß). Despite many observations of this association, the relationship between Aß and iron is poorly understood. Using X-ray microspectroscopy, X-ray absorption spectroscopy, electron microscopy and spectrophotometric iron(II) quantification techniques, we examine the interaction between Aß(1-42) and synthetic iron(III), reminiscent of ferric iron stores in the brain. We report Aß to be capable of accumulating iron(III) within amyloid aggregates, with this process resulting in Aß-mediated reduction of iron(III) to a redox-active iron(II) phase. Additionally, we show that the presence of aluminium increases the reductive capacity of Aß, enabling the redox cycling of the iron. These results demonstrate the ability of Aß to accumulate iron, offering an explanation for previously observed local increases in iron concentration associated with AD lesions. Furthermore, the ability of iron to form redox-active iron phases from ferric precursors provides an origin both for the redox-active iron previously witnessed in AD tissue, and the increased levels of oxidative stress characteristic of AD. These interactions between Aß and iron deliver valuable insights into the process of AD progression, which may ultimately provide targets for disease therapies.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides , Química Encefálica , Encéfalo/metabolismo , Compuestos Ferrosos , Hierro , Fragmentos de Péptidos , Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/metabolismo , Compuestos Ferrosos/química , Compuestos Ferrosos/metabolismo , Humanos , Hierro/química , Hierro/metabolismo , Estrés Oxidativo , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo
18.
J Inorg Biochem ; 117: 118-23, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23085591

RESUMEN

The possibility for an Al-superoxide complex to reduce Fe(III) to Fe(II), promoting oxidative damage through the Fenton reaction, is investigated using highly accurate ab initio methods and density functional theory in conjunction with solvation continuum methods to simulate bulk solvent effects. It is found that the redox reaction between Al-superoxide and Fe(III) to produce Fe(II) is exothermic. Moreover, the loss of an electron from the superoxide radical ion in the Al-superoxide complex leads to a spontaneous dissociation of molecular oxygen from aluminum, recovering therefore an Al(3+) hexahydrated complex. As demonstrated in previous studies, this complex is again prone to stabilize another superoxide molecule, suggesting a catalytic cycle that augments the concentration of Fe(II) in the presence of Al(III). Similar results are found for Al(OH)(2+) and Al(OH)(2)(+) hydrolytic species. Our work reinforces the idea that the presence of aluminum in biological systems could lead to an important pro-oxidant activity through a superoxide formation mechanism.


Asunto(s)
Aluminio/química , Compuestos Férricos/química , Compuestos Ferrosos/química , Peróxido de Hidrógeno/química , Hierro/química , Oxidantes/química , Hidrólisis , Oxidación-Reducción , Especies Reactivas de Oxígeno/química , Superóxidos/química
19.
Histol Histopathol ; 27(8): 1055-66, 2012 08.
Artículo en Inglés | MEDLINE | ID: mdl-22763878

RESUMEN

Silicon is not generally considered an essential nutrient for mammals and, to date, whether it has a biological role or beneficial effects in humans is not known. The results of a number of studies suggest that dietary silicon supplementation might have a protective effect both for limiting aluminium absorption across the gut and for the removal of systemic aluminium via the urine, hence, preventing potential accumulation of aluminium in the brain. Since our previous studies demonstrated that aluminium exposure reduces the number of nitrergic neurons, the aim of the present study was to compare the distribution and the morphology of NO-containing neurons in brain cortex of mice exposed to aluminium sulphate dissolved in silicic acid-rich or poor drinking water to assess the potential protective role of silicon against aluminium toxicity in the brain. NADPH-d histochemistry and nNOS immunohistochemistry showed that high concentrations of silicon in drinking water were able to minimize the impairment of the function of nitrergic neurons induced by aluminium administration. We found that silicon protected against aluminium-induced damage to the nitrergic system: in particular, we demonstrated that silicon maintains the number of nitrergic neurons and their expression of nitrergic enzymes at physiological levels, even after a 12 and 15 month exposure to aluminium.


Asunto(s)
Compuestos de Alumbre/toxicidad , Corteza Cerebral/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Neuronas Nitrérgicas/efectos de los fármacos , Ácido Silícico/farmacología , Contaminantes Químicos del Agua/toxicidad , Compuestos de Alumbre/análisis , Animales , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Ingestión de Líquidos , Agua Potable/química , Antagonismo de Drogas , Masculino , Ratones , Ratones Endogámicos C57BL , Aguas Minerales/análisis , NADPH Deshidrogenasa/metabolismo , Neuronas Nitrérgicas/metabolismo , Neuronas Nitrérgicas/patología , Óxido Nítrico Sintasa de Tipo I/metabolismo , Pruebas de Toxicidad Crónica , Contaminantes Químicos del Agua/análisis
20.
Br Dent J ; 213(1): 5, 2012 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-22790727
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