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1.
BMC Public Health ; 23(1): 417, 2023 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-36864433

RESUMO

BACKGROUND: Hypertension is the second leading risk factor for death in South Africa, and rates have steadily increased since the end of Apartheid. Research on the determinants of hypertension in South Africa has received considerable attention due to South Africa's rapid urbanization and epidemiological transition. However, scant work has been conducted to investigate how various segments of the Black South African population experience this transition. Identifying the correlates of hypertension in this population is critical to the development of policies and targeted interventions to strengthen equitable public health efforts. METHODS: This analysis explores the relationship between individual and area-level socioeconomic status and hypertension prevalence, awareness, treatment, and control within a sample of 7,303 Black South Africans in three municipalities of the uMgungundlovu district in KwaZulu-Natal province: the Msunduzi, uMshwathi, and Mkhambathini. Cross-sectional data were collected on participants from February 2017 to February 2018. Individual-level socioeconomic status was measured by employment status and educational attainment. Ward-level area deprivation was operationalized by the most recent (2011 and 2001) South African Multidimensional Poverty Index scores. Covariates included age, sex, BMI, and diabetes diagnosis. RESULTS: The prevalence of hypertension in the sample was 44.4% (n = 3,240). Of those, 2,324 were aware of their diagnosis, 1,928 were receiving treatment, and 1,051 had their hypertension controlled. Educational attainment was negatively associated with hypertension prevalence and positively associated with its control. Employment status was negatively associated with hypertension control. Black South Africans living in more deprived wards had higher odds of being hypertensive and lower odds of having their hypertension controlled. Those residing in wards that became more deprived from 2001 to 2011 had higher odds of being aware of their hypertension, yet lower odds of receiving treatment for it. CONCLUSIONS: Results from this study can assist policymakers and practitioners in identifying groups within the Black South African population that should be prioritized for public health interventions. Black South Africans who have and continue to face barriers to care, including those with low educational attainment or living in deprived wards had worse hypertension outcomes. Potential interventions include community-based programs that deliver medication to households, workplaces, or community centers.


Assuntos
Hipertensão , Humanos , África do Sul/epidemiologia , Estudos Transversais , Prevalência , Hipertensão/epidemiologia , Hipertensão/terapia , Pobreza
2.
Sci Adv ; 7(11)2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33692099

RESUMO

Energy-efficient recovery of oil droplets from ice-cold water, such as oil sands tailings, marine, and arctic oil spills, is challenging. In particular, due to paraffin wax crystallization at low temperatures, the crude oil exhibits high viscosity, making it difficult to collect using simple solutions like sponges. Here, we report a wax-wetting sponge designed by conforming to the thermoresponsive microstructure of crude oil droplets. To address paraffin wax crystallization, we designed the sponge by coating a polyester polyurethane substrate with nanosilicon functionalized with paraffin-like octadecyl ligands. The wax-wetting sponge can adsorb oil droplets from wastewater between 5° and 40°C with 90 to 99% removal efficacy for 10 cycles. Also, upon rinsing with heptol, the adsorbed oil is released within seconds. The proposed approach of sponges designed to conform with the temperature-dependent microstructure of the crude oils could enable cold water technologies and improve circular economy metrics in the oil industry.

3.
J Dairy Sci ; 103(10): 9301-9317, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32921376

RESUMO

Due to the increased morbidity and mortality of bovine respiratory disease (BRD) in dairy calves, as well as an increasing urgency for the judicious use of antimicrobials in farm animals, a comprehensive risk assessment tool for BRD in preweaned dairy calves has been designed based on a longitudinal and a cross-sectional study. As a multifactorial disease complex in which immune function stressors increase susceptibility to respiratory pathology, risk management programs for environmental and husbandry practices may be an effective approach for BRD control. Practices of known or suspected effect on BRD in preweaned calves have been explored in 2 large studies correlating management factors to BRD prevalence (BRD 100 study) and incidence (BRD 10K study) and forming the scores presented here. Priority was given to results from multivariable over univariable model estimates. However, when used, univariable model estimates were adjusted for confounders or stratified by effect modifiers if necessary. Regression coefficients were translated into scores, which are presented in a field-ready tool consisting of (1) a risk assessment questionnaire, which identifies the herd-specific risk factors and the risk scores associated with each; (2) the California BRD scoring system to estimate the BRD prevalence at the time of risk assessment for future comparison with the prevalence after interventions; and (3) the BRD control and prevention herd management plan, which can be used to plan and track the interventions identified. Scores for 100 dairies across California were used to benchmark a dairy's risk on a spectrum. With the help of the risk assessment tool, dairy producers, calf managers, and veterinarians may be able to adjust management factors that affect BRD risk on a farm and objectively monitor BRD prevalence before and after management interventions. As a result, the BRD risk assessment tool described here is the first comprehensive effort for herd-specific BRD control and prevention.


Assuntos
Complexo Respiratório Bovino/epidemiologia , Indústria de Laticínios , Medição de Risco/métodos , Animais , Animais Recém-Nascidos , Complexo Respiratório Bovino/diagnóstico , Complexo Respiratório Bovino/etiologia , Bovinos , Estudos Transversais , Indústria de Laticínios/métodos , Feminino , Incidência , Leite , Prevalência , Inquéritos e Questionários , Desmame
4.
Opt Lett ; 45(4): 840-843, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32058484

RESUMO

Offset aperture and split detector imaging are variants of adaptive optics scanning ophthalmoscopy recently introduced to improve the image contrast of retinal cells. Unlike conventional confocal scanning ophthalmoscopy, these approaches collect light laterally decentered from the optical axis. A complete explanation of how these methods enhance contrast has not been described. Here, we provide an optical model with supporting in vivo data that show contrast is generated from spatial variations in the refractive index as it is in phase contrast microscopy. A prediction of this model is supported by experimental data that show contrast is optimized when the detector is placed conjugate with a deeper backscattering screen such as the retinal pigment epithelium and choroid, rather than with the layer being imaged as in conventional confocal imaging. This detection strategy provides a substantial improvement in the contrast these new methods can produce.


Assuntos
Oftalmoscopia/métodos , Fenômenos Ópticos , Animais , Camundongos , Retina/diagnóstico por imagem , Razão Sinal-Ruído
5.
Adsorption (Boston) ; 25(6): 1177-1190, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435138

RESUMO

Protein adsorption on solid state media is important for the industrial affinity chromatography of biotherapeutics and for preparing materials for self-interaction chromatography where fundamental protein solution thermodynamic properties are measured. The adsorption of three model proteins (lysozyme, catalase and BSA) and two antibodies (a monoclonal and a polyclonal antibody) have been investigated on commercial affinity chromatography media with different surface functionalities (Formyl, Tresyl and Amino). Both the extent of protein immobilised (mg protein/ml media) and the reaction kinetics are reported for a range of reaction conditions, including pH, differing buffers as well as the presence of secondary reactants (glutaraldehyde, sodium cyanoborohydride, EDC and NHS). Compared to the reaction conditions recommended by manufacturers as well as those reported in previous published work, significant increases in the extent of protein immobilisation and reaction kinetics are reported here. The addition of glutaraldehyde or sodium cyanoborohydride was found to be especially effective even when not directly needed for the adsorption to happen. For mAb and pIgG, immobilisation levels of 50 and 31 mg of protein/ml of resin respectively were achieved, which are 100% or more than previously reported. Enhanced levels were achieved for lysozyme of 120 mg/ml with very rapid reaction kinetics (< 1 h) with sodium cyanoborohydride. It can be concluded that specific chromatography resins with Tresyl activated support offered enhanced levels of protein immobilisation due to their ability to react to form amine or thio-ether linkages with proteins. Additionally, glutaraldehyde can result in higher immobilisation levels whilst it can also accelerate immobilisation reaction kinetics.

6.
J Dairy Sci ; 102(8): 7288-7305, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202656

RESUMO

The objective of this cross-sectional study was to determine how management practices on California dairies may be associated with bovine respiratory disease (BRD) in preweaned calves. A convenience sample of 100 dairies throughout California, providing a study population of 4,636 calves, were visited between May 2014 and April 2016. During each farm visit, in-person interviews with the herd manager or calf caretaker were conducted to collect information about herd demographics, maternity pen, colostrum and calf management, herd vaccinations, and dust abatement. A random sample of preweaned calves was identified and evaluated for the presence of BRD using a standardized tool. A survey-adjusted generalized linear mixed model with a logit link function was fitted with calf as the unit of analysis and dairy as the random effect. Mean study herd size (±SE) was 1,718 (±189.9) cows. Survey-adjusted estimates of breed types in the sample were 81.6% (±0.6) Holstein, 13.1% (±0.4) Jersey, and 5.3% (±0.5) crossbred or other purebred breeds, and calf sex proportions were 73.8% (±1.0) female and 26.2% (±1.0) male. Overall survey-adjusted BRD prevalence in the study herds was 6.91% (±0.69). Housing factors positively associated with BRD were metal hutches compared with wood hutches [odds ratio (OR) = 11.19; 95% confidence interval (CI) = 2.80-44.78], calf-to-calf contact in calves >75 d of age (OR = 9.95, 95% CI = 1.50-65.86), feeding Holstein calves <2.84 L of milk or replacer per day (OR = 7.16, 95% CI = 1.23-41.68), and lagoon water used for flushing manure under hutches compared with no flush (OR = 12.06, 95% CI = 1.93-75.47). Providing extra shade over hutches (OR = 0.08; 95% CI = 0.02-0.37), feeding calves at least 90% saleable milk (OR = 0.27, 95% CI = 0.13-0.54) or pasteurized milk (OR = 0.10; 95% CI = 0.03-0.36), and feeding >5.68 L of milk or replacer per day to Jersey calves (OR = 0.04; 95% CI = 0.01-0.28) were negatively associated with BRD. Our study identified management practices on California dairies with variability and that may contribute to differences in BRD prevalence, which will be incorporated into a risk-assessment tool to control and prevent BRD in preweaned dairy calves.


Assuntos
Complexo Respiratório Bovino/epidemiologia , Indústria de Laticínios/métodos , Desmame , Animais , Complexo Respiratório Bovino/prevenção & controle , California/epidemiologia , Bovinos , Colostro , Estudos Transversais , Dieta/veterinária , Fazendas , Feminino , Abrigo para Animais , Masculino , Leite , Razão de Chances , Gravidez , Medição de Risco
7.
J Dairy Sci ; 102(8): 7583-7596, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30527977

RESUMO

The objective of this cross-sectional study was to estimate the prevalence of bovine respiratory disease (BRD) in California preweaned dairy calves and identify management practices that are associated with BRD. A convenience sample of 100 dairies in the 3 distinct dairy regions of California was surveyed. Regions evaluated were Northern California (NCA), northern San Joaquin Valley (NSJV), and greater Southern California (GSCA). A questionnaire on calf management practices and demographic information was administered via in-person interviews at each dairy and a random sample of preweaned calves was evaluated using the California BRD scoring system on the same day. Prevalence of BRD varied between the 3 dairy regions: 9.30% in NCA, 4.51% in NSJV, and 7.35% in GSCA. Breed was not associated with BRD prevalence at the statewide level, but differences in prevalence were observed between breeds across the regions with a higher prevalence in NCA for Jerseys and in GSCA for Holsteins, compared with NSJV. Prevalence of BRD was not different between organic and conventional dairies. Colostrum management practices, including heat treatment and feeding colostrum from multiparous cows, varied by region and were associated with lower BRD prevalence. Calves housed in group pens, a practice observed primarily in NCA, had a higher BRD prevalence than those in individual housing. Feeding salable milk was also more common in NCA and was associated with lower BRD prevalence. Ground and road surfaces adjacent to the calf raising area were also variable by region, and paved surfaces were associated with lower BRD prevalence. Management practices associated with BRD varied across the state and may be addressed to inform the adoption and implementation of potentially protective management decisions on California dairies and other regions with similar dairy systems.


Assuntos
Doenças dos Bovinos/prevenção & controle , Doenças Respiratórias/veterinária , Animais , Cruzamento , California/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/metabolismo , Estudos Transversais , Feminino , Masculino , Leite/metabolismo , Gravidez , Prevalência , Doenças Respiratórias/epidemiologia , Doenças Respiratórias/metabolismo , Doenças Respiratórias/prevenção & controle
8.
J Phys Chem A ; 122(45): 8923-8930, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30354125

RESUMO

Interlocked molecules exhibit structural isomerization that is different from that of molecules whose connectedness is solely through covalent bonds. A mechanical bond, or the interlocking of components, provides a rich conformational landscape. The ability of synthetic chemists to design directional motion between these mechanical conformers suggests mechanical bonds as building blocks in the design of synthetic molecular motors and machines. Here we examine the complexity of mechanical conformers of radial catenanes with n anisotropically repulsive rings (coined "keyrings") threaded onto a single central ring for n ≤ 10. For a given number of rings, n, the ratio of the key length to the main ring radius, λ, determines the mechanical conformer. We show that this system displays symmetrical in-plane conformers for short keys and co-conformers of lower symmetry where the keys lie out of the plane for longer keys.

10.
S Afr Med J ; 109(1): 40-46, 2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30606303

RESUMO

BACKGROUND: Hazardous alcohol consumption presents a serious threat to the health and wellbeing of all people and is linked to chronic and acute health problems. OBJECTIVES: To: (i) estimate the prevalence of alcohol use disorders and remission from alcohol abuse and dependence in the South African (SA) population; and (ii) determine whether age of onset, education, sex and level of cohort alcohol use are associated with commencement of use, regularity of use, and transitions to and remission from more harmful levels of use. METHODS: The study was a nationally representative sample of 4 315 individuals aged ≥18 years. In a multistage, area probability sample of adults, data were collected from 4 311 alcohol users using the World Mental Health Survey Initiative version of the Composite International Diagnostic Interview version 3.0. All analyses were carried out using SAS version 9.4. RESULTS: Of the respondents, 40.6% indicated lifetime use of alcohol, 35.3% reported regular use, and 8.8% met diagnostic criteria for alcohol abuse and 2.7% for alcohol dependence. The prevalence of remission from lifetime abuse without dependence was 55.9%. The median age of onset of alcohol use was 20 years, with transition from use to regular use occurring within ~1 - 3 years. The results suggest that males, students (compared with those who had completed a high level of education) and greater alcohol use in the respondent's birth cohort were all associated with increased odds of commencing alcohol use. For transitions from use to regular use, increased odds were associated with males, greater birth cohort alcohol use, low education and later (>21 years) onset of first alcohol use. CONCLUSIONS: Our findings suggest that cohort alcohol use is associated with transition to commencement of use and from use to regular use in the general SA population. The study further highlighted the need for interventions among males and university students, given that hazardous alcohol consumption seems to be the most prevalent public health issue encountered by university students and males.

11.
SSM Popul Health ; 4: 17-24, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29250579

RESUMO

This essay examines how civil rights and their implementation have affected and continue to affect the health of racial and ethnic minority populations in the United States. Civil rights are characterized as social determinants of health. A brief review of US history indicates that, particularly for Blacks, Hispanics, and American Indians, the longstanding lack of civil rights is linked with persistent health inequities. Civil rights history since 1950 is explored in four domains-health care, education, employment, and housing. The first three domains show substantial benefits when civil rights are enforced. Discrimination and segregation in housing persist because anti-discrimination civil rights laws have not been well enforced. Enforcement is an essential component for the success of civil rights law. Civil rights and their enforcement may be considered a powerful arena for public health theorizing, research, policy, and action.

12.
Psychol Med ; 48(9): 1560-1571, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29173244

RESUMO

BACKGROUND: The treatment gap between the number of people with mental disorders and the number treated represents a major public health challenge. We examine this gap by socio-economic status (SES; indicated by family income and respondent education) and service sector in a cross-national analysis of community epidemiological survey data. METHODS: Data come from 16 753 respondents with 12-month DSM-IV disorders from community surveys in 25 countries in the WHO World Mental Health Survey Initiative. DSM-IV anxiety, mood, or substance disorders and treatment of these disorders were assessed with the WHO Composite International Diagnostic Interview (CIDI). RESULTS: Only 13.7% of 12-month DSM-IV/CIDI cases in lower-middle-income countries, 22.0% in upper-middle-income countries, and 36.8% in high-income countries received treatment. Highest-SES respondents were somewhat more likely to receive treatment, but this was true mostly for specialty mental health treatment, where the association was positive with education (highest treatment among respondents with the highest education and a weak association of education with treatment among other respondents) but non-monotonic with income (somewhat lower treatment rates among middle-income respondents and equivalent among those with high and low incomes). CONCLUSIONS: The modest, but nonetheless stronger, an association of education than income with treatment raises questions about a financial barriers interpretation of the inverse association of SES with treatment, although future within-country analyses that consider contextual factors might document other important specifications. While beyond the scope of this report, such an expanded analysis could have important implications for designing interventions aimed at increasing mental disorder treatment among socio-economically disadvantaged people.


Assuntos
Países Desenvolvidos/estatística & dados numéricos , Países em Desenvolvimento/estatística & dados numéricos , Disparidades em Assistência à Saúde/estatística & dados numéricos , Transtornos Mentais/terapia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Fatores Socioeconômicos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Inquéritos Epidemiológicos , Humanos , Internacionalidade , Modelos Logísticos , Masculino , Saúde Mental , Pessoa de Meia-Idade , Análise Multivariada , Psicoterapia , Adulto Jovem
13.
J Chromatogr A ; 1459: 47-56, 2016 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-27417064

RESUMO

Self-interaction chromatography (SIC) has established itself as an important experimental technique for the measurement of the second osmotic virial coefficients B22. B22 data are critical for understanding a range of protein solution phenomena, particularly aggregation and crystallisation. A key limitation to the more extensive use of SIC is the need to develop a method for immobilising each specific protein of interest onto a chromatographic support. This requirement is both a time and protein consuming constraint, which means that SIC cannot be used as a high throughput method for screening a wide range of proteins and their variants. Here an experimental framework is presented for estimating B22 values using Similar Interaction Chromatography (SimIC). This work uses experimental B23 and B32 data for lysozyme, lactoferrin, catalase and concanavalin A to reliably estimate B22 using arithmetic mean field approximations and is demonstrated to give good agreement with SIC measurements of B22 for the same proteins. SimIC could form the basis of a rapid protein variant screening methods to assess the developability of protein therapeutic candidates for industrial and academic researchers with respect to aggregation behaviour by eluting target proteins through a series of well-characterised protein immobilized reference columns.


Assuntos
Cromatografia , Osmose , Proteínas/química , Animais , Varredura Diferencial de Calorimetria , Catalase/química , Catalase/metabolismo , Concanavalina A/química , Concanavalina A/metabolismo , Humanos , Lactoferrina/química , Lactoferrina/metabolismo , Muramidase/química , Muramidase/metabolismo , Proteínas/metabolismo , Cloreto de Sódio/química , Soluções/química
14.
Soc Psychiatry Psychiatr Epidemiol ; 51(5): 689-701, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26875153

RESUMO

PURPOSE: Few studies have examined discrimination and mental health in the UK, particularly by migrant status and in urban contexts with greater demographic diversity. This study aims to (1) describe the prevalence of discrimination experiences across multiple life domains; (2) to describe associations between discrimination experiences and common mental disorder (CMD); (3) to determine whether or not the relationship between discrimination and CMD varies by migrant status and ethnicity. METHODS: Data on major, anticipated and everyday discrimination and CMD symptoms were collected from an ethnically diverse prospective sample of 1052 participants followed up from 2008 to 2013 in the South East London Community Health study, a population-based household survey. RESULTS: With few exceptions, discrimination was most prevalent among those in the Black Caribbean group. However, those in the White Other ethnic group had similar or greater reporting major and anticipated discrimination to Black or mixed ethnic minority groups. The effects of discrimination on CMD were most pronounced for individuals who had recently migrated to the UK, an ethnically heterogeneous group, and for Black and Mixed ethnic minority groups in partially adjusted models. Prior CMD accounted for differences between the Mixed and White British ethnic groups, but the strength of the association for the most recent migrant group and the Black ethnic groups remained two or more times greater than the reference groups. CONCLUSIONS: The strength of the relationship suggests a need for more consideration of migration status along with ethnicity in examining the impact of discrimination on mental disorder in community and clinical samples.


Assuntos
Emigrantes e Imigrantes/psicologia , Emigrantes e Imigrantes/estatística & dados numéricos , Etnicidade/psicologia , Etnicidade/estatística & dados numéricos , Transtornos Mentais/etnologia , Transtornos Mentais/psicologia , Racismo , Adolescente , Adulto , Feminino , Humanos , Londres , Masculino , Transtornos Mentais/diagnóstico , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Estatística como Assunto , Adulto Jovem
15.
J Chromatogr A ; 1434: 57-63, 2016 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-26810801

RESUMO

Self-interaction chromatography is known to be a fast, automated and promising experimental technique for determination of B22, but with the primary disadvantage of needing a significant amount of protein (>50 mg). This requirement compromises its usage as a technique for the early screening of new biotherapeutic candidates. A new scaled down SIC method has been evaluated here using a number of micro LC columns of different diameters and lengths, using typically 10 times less stationary phase than traditional SIC. Scale-down was successfully accomplished using these micro-columns, where the SIC results for a range of differing columns sizes were in agreement, as reflected by k', B22 and column volumes data. The results reported here demonstrate that a scaled down version of SIC can be easily implemented using conventional liquid chromatography system where the final amount of mAbs used was 10 times less than required by conventional SIC methodologies.


Assuntos
Anticorpos Monoclonais/química , Cromatografia Líquida/métodos , Muramidase/química , Animais , Galinhas , Cromatografia Líquida/instrumentação
16.
Pharm Res ; 32(12): 3975-85, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26268546

RESUMO

PURPOSE: Measurement of the second virial coefficient B22 for proteins using self-interaction chromatography (SIC) is becoming an increasingly important technique for studying their solution behaviour. In common with all physicochemical chromatographic methods, measuring the dead volume of the SIC packed column is crucial for accurate retention data; this paper examines best practise for dead volume determination. METHOD: SIC type experiments using catalase, BSA, lysozyme and a mAb as model systems are reported, as well as a number of dead column measurements. RESULTS: It was observed that lysozyme and mAb interacted specifically with Toyopearl AF-Formyl dead columns depending upon pH and [NaCl], invalidating their dead volume usage. Toyopearl AF-Amino packed dead columns showed no such problems and acted as suitable dead columns without any solution condition dependency. Dead volume determinations using dextran MW standards with protein immobilised SIC columns provided dead volume estimates close to those obtained using Toyopearl AF-Amino dead columns. CONCLUSION: It is concluded that specific interactions between proteins, including mAbs, and select SIC support phases can compromise the use of some standard approaches for estimating the dead volume of SIC columns. Two other methods were shown to provide good estimates for the dead volume.


Assuntos
Anticorpos Monoclonais/química , Cromatografia/métodos , Animais , Bovinos , Galinhas , Muramidase/química , Soroalbumina Bovina/química , Soluções/química
17.
Eur J Pharm Biopharm ; 96: 282-90, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26259782

RESUMO

The second osmotic virial coefficients (b2) of four proteins - lysozyme, recombinant human lactoferrin, concanavalin A and catalase were measured by self-interaction chromatography (SIC) in solutions of varying salt type, concentration and pH. Protein aggregate sizes based on the initial hydrodynamic radius of the protein solution species present were measured using dynamic light scattering, and the relationship between b2 and protein aggregate size was studied. A linear correlation was established between b2 values and protein aggregate hydrodynamic size for all proteins, and for almost all solution conditions. Aggregate sizes of <∼10nm, indicative of non-aggregated protein systems, were consistently observed to have b2 values >0. The observed b2 trends as a function of solution conditions were very much protein dependent, with notable trends including the existence of attractive interactions (negative b2 values) at low ionic strengths for catalase and concanavalin A, and the highly positive b2 values observed for lactoferrin over a wide range of solution conditions, reflecting lactoferrin's innately high stability. It is concluded that the quantification of protein-protein interactions using SIC based b2 data is a potentially valuable screening tool for predicting protein aggregation propensity.


Assuntos
Catalase/química , Concanavalina A/química , Lactoferrina/química , Modelos Moleculares , Muramidase/química , Agregados Proteicos , Algoritmos , Animais , Bovinos , Galinhas , Composição de Medicamentos , Estabilidade de Medicamentos , Estabilidade Enzimática , Enzimas Imobilizadas/química , Humanos , Concentração de Íons de Hidrogênio , Proteínas Imobilizadas/química , Lactoferrina/genética , Lactoferrina/metabolismo , Microesferas , Domínios e Motivos de Interação entre Proteínas , Estabilidade Proteica , Proteínas Recombinantes/química , Soluções
18.
Biomed Opt Express ; 6(6): 2106-19, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26114032

RESUMO

The transparency of most retinal cell classes typically precludes imaging them in the living eye; unless invasive methods are used that deploy extrinsic contrast agents. Using an adaptive optics scanning light ophthalmoscope (AOSLO) and capitalizing on the large numerical aperture of the mouse eye, we enhanced the contrast from otherwise transparent cells by subtracting the left from the right half of the light distribution in the detector plane. With this approach, it is possible to image the distal processes of photoreceptors, their more proximal cell bodies and the mosaic of horizontal cells in the living mouse retina.

19.
Diabet Med ; 32(12): 1662-6, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25916313

RESUMO

AIMS: To assess the impact of continual major National Health Service reorganization on commissioning, organizational and delivery arrangements for secondary care diabetes services. To explore how consultant diabetologists and diabetes specialist nurses perceive the issues facing diabetes specialist services in 2011 and how these have changed in the preceding decade. METHODS: We used a longitudinal case study approach that combined quantitative and qualitative methods. Five locations in England were purposively selected to represent the wider diabetes specialist community, and seven semi-structured interviews were conducted. Interviews were recorded, transcribed verbatim and analysed using Framework analysis. Findings were compared with and contrasted to results from national quantitative surveys of diabetes specialist services undertaken in 2000 and 2006. RESULTS: Clinicians viewed positively the expertise and commitment of multidisciplinary teams and their ability to adapt to new situations. Negative perceptions persisted throughout the decade, relating to the continual change that threatens to dismantle relationships and services which had taken many years to establish. Lack of resources, inadequate manpower planning and poor access to psychological support for people with diabetes remained constant themes from 2000 to 2011. CONCLUSIONS: A willingness to innovate and work differently to improve services was identified; however, clinicians must be supported through organizational changes to ensure people with diabetes receive high-quality care. The disruptive nature of organizational change was a recurrent theme throughout the decade. Periods of stability must exist within commissioning to allow relationships, which are key to integration, to be maintained and permit service improvements to develop.


Assuntos
Atitude do Pessoal de Saúde , Consultores , Diabetes Mellitus/terapia , Enfermeiros Clínicos , Equipe de Assistência ao Paciente/normas , Qualidade da Assistência à Saúde , Especialização , Adolescente , Adulto , Criança , Terapia Combinada/enfermagem , Terapia Combinada/normas , Terapia Combinada/tendências , Inglaterra , Reforma dos Serviços de Saúde/tendências , Pesquisas sobre Atenção à Saúde , Humanos , Estudos Longitudinais , Moral , Estudos de Casos Organizacionais , Equipe de Assistência ao Paciente/tendências , Médicos , Qualidade da Assistência à Saúde/tendências , Medicina Estatal
20.
Eur J Pharm Biopharm ; 85(3 Pt B): 1103-11, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23623796

RESUMO

Measurement of B22, the second virial coefficient, is an important technique for describing the solution behaviour of proteins, especially as it relates to precipitation, aggregation and crystallisation phenomena. This paper describes the best practise for calculating B22 values from self-interaction chromatograms (SIC) for aqueous protein solutions. Detailed analysis of SIC peak shapes for lysozyme shows that non-Gaussian peaks are commonly encountered for SIC, with typical peak asymmetries of 10%. This asymmetry reflects a non-linear chromatographic retention process, in this case heterogeneity of the protein-protein interactions. Therefore, it is important to use the centre of mass calculations for determining accurate retention volumes and thus B22 values. Empirical peak maximum chromatogram analysis, often reported in the literature, can result in errors of up to 50% in B22 values. A methodology is reported here for determining both the mean and the variance in B22 from SIC experiments, includes a correction for normal longitudinal peak broadening. The variance in B22 due to chemical effects is quantified statistically and is a measure of the heterogeneity of protein-protein interactions in solution. In the case of lysozyme, a wide range of B22 values are measured which can vary significantly from the average B22 values.


Assuntos
Cromatografia/métodos , Muramidase/química , Animais , Química Farmacêutica/métodos , Galinhas , Cristalização , Difusão , Concentração de Íons de Hidrogênio , Proteínas/química , Valores de Referência , Reprodutibilidade dos Testes , Sais/química , Soluções , Temperatura , Termodinâmica
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