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1.
Lancet Reg Health West Pac ; 42: 100961, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38022711

RESUMEN

Background: Women comprise 90% of patient-facing global healthcare workers (HCWs), yet remain underpaid, undervalued, and under-represented in leadership and decision-making positions, particularly across the Pacific region. The COVID-19 pandemic has exacerbated these health workplace inequalities. We sought to understand Pacific women HCWs experience from the COVID-19 frontline to contribute to policies aimed at addressing gendered gaps in regional health systems. Methods: Our interpretative phenomenological study used critical feminist and social theory, and a gendered health systems analytical framework. Data were collected using online focus groups and in-depth interviews with 36 Pacific regional participants between March 2020 and July 2021. Gender-specific content and women's voices were privileged for inductive analysis by Pacific and Australian women researchers with COVID-19 frontline lived experience. Findings: Pacific women HCWs have authority and responsibility resulting from their familial, biological, and cultural status, but are often subordinate to men. They were emancipatory leaders during COVID-19, and as HCWs demonstrated compassion, situational awareness, and concern for staff welfare. Pacific women HCWs also faced ethical challenges to prioritise family or work responsibilities, safely negotiate childbearing, and maintain economic security. Interpretation: Despite enhanced gendered power differentials during COVID-19, Pacific women HCWs used their symbolic capital to positively influence health system performance. Gender-transformative policies are urgently required to address disproportionate clinical and community care burdens and to protect and support the Pacific female health workforce. Funding: Epidemic Ethics/World Health Organization (WHO), Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Co-funding: Australasian College for Emergency Medicine Foundation, International Development Fund Grant.

2.
Expert Opin Drug Discov ; 18(7): 753-768, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37219915

RESUMEN

INTRODUCTION: Identifying effective cancer drugs remains an inefficient process. Drug efficacy in traditional preclinical cancer models translates poorly into therapy in the clinic. Implementation of preclinical models that incorporate the tumor microenvironment (TME) is needed to improve selection of active drugs prior to clinical trials. AREAS COVERED: Progression of cancer results from the behavior of cancer cells in concert with the host's histopathological background. Nonetheless, complex preclinical models with a relevant microenvironment have yet to become an integral part of drug development. This review discusses existing models and provides a synopsis of active areas of cancer drug development where implementation would be of value. Their contribution to finding therapeutics in immune oncology, angiogenesis, regulated cell death and targeting tumor fibroblasts as well as optimization of drug delivery, combination therapy, and biomarkers of efficacy is considered. EXPERT OPINION: Complex tumor models in vitro (CTMIVs) that mimic the organotypic architecture of neoplastic tumors have boosted research into TME influence on traditional cytoreductive chemotherapy as well as the detection of specific TME targets. Despite advances in technical prowess, CTMIVs can only address specific aspects of cancer pathophysiology.


Asunto(s)
Antineoplásicos , Neoplasias , Humanos , Microambiente Tumoral , Neoplasias/patología , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Sistemas de Liberación de Medicamentos/métodos , Desarrollo de Medicamentos
3.
J Mol Med (Berl) ; 101(4): 375-385, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36808265

RESUMEN

Familial adenomatous polyposis (FAP) is a precancerous, colorectal disease characterized by hundreds to thousands of adenomatous polyps caused by mutations in the tumor suppressor gene adenomatous polyposis coli (APC). Approximately 30% of these mutations are premature termination codons (PTC), resulting in the production of a truncated, dysfunctional APC protein. Consequently, the ß-catenin degradation complex fails to form in the cytoplasm, leading to elevated nuclear levels of ß-catenin and unregulated ß-catenin/wnt-pathway signaling. We present in vitro and in vivo data demonstrating that the novel macrolide, ZKN-0013, promotes read through of premature stop codons, leading to functional restoration of full-length APC protein. Human colorectal carcinoma SW403 and SW1417 cells harboring PTC mutations in the APC gene showed reduced levels of nuclear ß-catenin and c-myc upon treatment with ZKN-0013, indicating that the macrolide-mediated read through of premature stop codons produced bioactive APC protein and inhibited the ß-catenin/wnt-pathway. In a mouse model of adenomatous polyposis coli, treatment of APCmin mice with ZKN-0013 caused a significant decrease in intestinal polyps, adenomas, and associated anemia, resulting in increased survival. Immunohistochemistry revealed decreased nuclear ß-catenin staining in the epithelial cells of the polyps in ZKN-0013-treated APCmin mice, confirming the impact on the ß-catenin/wnt-pathway. These results indicate that ZKN-0013 may have therapeutic potential for the treatment of FAP caused by nonsense mutations in the APC gene. KEY MESSAGES: • ZKN-0013 inhibited the growth of human colon carcinoma cells with APC nonsense mutations. • ZKN-0013 promoted read through of premature stop codons in the APC gene. • In APCmin mice, ZKN-0013 treatment reduced intestinal polyps and their progression to adenomas. • ZKN-0013 treatment in APCmin mice resulted in reduced anemia and increased survival.


Asunto(s)
Adenoma , Poliposis Adenomatosa del Colon , Humanos , Animales , Ratones , Genes APC , beta Catenina/metabolismo , Codón sin Sentido , Poliposis Adenomatosa del Colon/tratamiento farmacológico , Poliposis Adenomatosa del Colon/genética , Poliposis Adenomatosa del Colon/patología , Adenoma/genética , Macrólidos , Pólipos Intestinales/genética
4.
Lancet Reg Health West Pac ; 25: 100517, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35818574

RESUMEN

Low- and middle-income countries (LMICs) across the Pacific region have been severely impacted by the COVID-19 pandemic, and emergency care (EC) clinicians have been on the frontline of response efforts. Their responsibilities have extended from triage and clinical management of patients with COVID-19 to health system leadership and coordination. This has exposed EC clinicians to a range of ethical and operational challenges.This paper describes the context and methodology of a rapid, collaborative, qualitative research project that explored the experiences of EC clinicians in Pacific LMICs during the COVID-19 pandemic. The study was conducted in three phases, with data obtained from online regional EC support forums, key informant interviews and focus group discussions. A phenomenological approach was adopted, incorporating a hybrid inductive and deductive thematic analysis. Research findings, reported in other manuscripts in this collection, will inform multi-sectoral efforts to improve health system preparedness for future public health emergencies. Funding: Epidemic Ethics/World Health Organization (WHO) initiative, supported by Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z (Phases 1 and 2A) and an Australasian College for Emergency Medicine Foundation International Development Fund Grant.

5.
Lancet Reg Health West Pac ; 25: 100518, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35818573

RESUMEN

Background: Universal access to safe, effective emergency care (EC) during the COVID-19 pandemic has illustrated its centrality to healthcare systems. The 'Leadership and Governance' building block provides policy, accountability and stewardship to health systems, and is essential to determining effectiveness of pandemic response. This study aimed to explore the experience of leadership and governance during the COVID-19 pandemic from frontline clinicians and stakeholders across the Pacific region. Methods: Australian and Pacific researchers collaborated to conduct this large, qualitative research project in three phases between March 2020 and July 2021. Data was gathered from 116 Pacific regional participants through online support forums, in-depth interviews and focus groups. A phenomenological approach shaped inductive and deductive data analysis, within a previously identified Pacific EC systems building block framework. Findings: Politics profoundly influenced pandemic response effectiveness, even at the clinical coalface. Experienced clinicians spoke authoritatively to decision-makers; focusing on safety, quality and service duty. Rapid adaptability, past surge event experience, team-focus and systems-thinking enabled EC leadership. Transparent communication, collaboration, mutual respect and trust created unity between frontline clinicians and 'top-level' administrators. Pacific cultural assets of relationship-building and community cohesion strengthened responses. Interpretation: Effective governance occurs when political, administrative and clinical actors work collaboratively in relationships characterised by trust, transparency, altruism and evidence. Trained, supported EC leadership will enhance frontline service provision, health security preparedness and future Universal Health Coverage goals. Funding: Epidemic Ethics/World Health Organization (WHO), Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Co-funding: Australasian College for Emergency Medicine Foundation, International Development Fund Grant.

6.
Lancet Reg Health West Pac ; 25: 100516, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35818575

RESUMEN

Background: The COVID-19 pandemic highlighted challenges for all health systems worldwide. This research aimed to explore the impact of COVID-19 across the Pacific especially with regards to emergency care (EC) and clinicians' preparations and responses. Methods: A collaboration of Australia and Pacific researchers conducted prospective qualitative research over 18 months of the pandemic. In this three phase study data were gathered from Emergency Clinicians and stakeholders through online support forums, in-depth interviews and focus groups. A phenomenological methodological approach was employed to explore the lived experience of participants. This paper discusses the findings of the study regarding the EC building block of 'Infrastructure and Equipment.' Findings: Pre-existing infrastructure and equipment were not sufficient to help control the pandemic. Adequate space and correct equipment were essential needs for Pacific Island emergency clinicians, with donations, procurement and local ingenuity required for suitable, sustainable supplies and facilities. Adequate personal protective equipment (PPE) conferred a sense of security and increased Health Care Workers willingness to attend to patients. Interpretation: Investing in adequate infrastructure and appropriate equipment is crucial for an effective response to the COVID-19 pandemic. The sustainability of such investments in the Pacific context is paramount for ongoing EC and preparation for future surge responses and disasters. Funding: Phases 1 and 2A of this study were part of an Epidemic Ethics/World Health Organization (WHO) initiative, supported by Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Co-funding for this research was received from the Australasian College for Emergency Medicine Foundation via an International Development Fund Grant.

7.
Lancet Reg Health West Pac ; 25: 100515, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35818576

RESUMEN

Background: Emergency care (EC) addresses the needs of patients with acute illness and injury, and has fulfilled a critical function during the COVID-19 pandemic. 'Processes' (e.g. triage) and 'data' (e.g. surveillance) have been nominated as essential building blocks for EC systems. This qualitative research sought to explore the impact of the pandemic on EC clinicians across the Pacific region, including the contribution of EC building blocks to effective responses. Methods: The study was conducted in three phases, with data obtained from online support forums, key informant interviews and focus group discussions. There were 116 participants from more than 14 Pacific Island Countries and Territories. A phenomenological approach was adopted, incorporating inductive and deductive methods. The deductive thematic analysis utilised previously identified building blocks for Pacific EC. This paper summarises findings for the building blocks of 'processes' and 'data'. Findings: Establishing triage and screening capacity, aimed at assessing urgency and transmission risk respectively, were priorities for EC clinicians. Enablers included support from senior hospital leaders, previous disaster experience and consistent guidelines. The introduction of efficient patient flow processes, such as streaming, proved valuable to emergency departments, and checklists and simulation were useful implementation strategies. Some response measures impacted negatively on non-COVID patients, and proactive approaches were required to maintain 'business as usual'. The pandemic also highlighted the value of surveillance and performance data. Interpretation: Developing effective processes for triage, screening and streaming, among other areas, was critical to an effective EC response. Beyond the pandemic, strengthening processes and data management capacity will build resilience in EC systems. Funding: Phases 1 and 2A of this study were part of an Epidemic Ethics/World Health Organization (WHO) initiative, supported by Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Co-funding for this research was received from the Australasian College for Emergency Medicine Foundation via an International Development Fund Grant.

8.
Lancet Reg Health West Pac ; 25: 100514, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35815241

RESUMEN

Background: This study explores emergency care (EC) and other frontline healthcare worker (HCW) experiences responding to the COVID-19 pandemic in the Pacific region. The crisis has reinforced the crucial role well-trained, resourced, and supported EC providers play in supporting vital health systems and services in all global regions not only during 'business as usual' periods, but in times of tremendous stress and surge. Methods: Qualitative data were collected from EC providers and relevant stakeholders in three research phases in 2020 and 2021. Data on the World Health Organization's (WHO) Human Resources Building Block, adapted for the Pacific EC context, was thematically analysed. Key findings were further analysed to identify enablers and barriers to effective EC pandemic management. Findings: 116 participants from across the Pacific region participated in this study. Five themes emerged: (1) EC providers performed multiple pandemic roles; (2) Importance of authorities' valuing frontline HCWs; (3) HCW mental health and exhaustion; (4) HCW tension managing stigma, personal/professional expectations, and chronic health needs; and (5) Building health and human resource capacity. Interpretation: This study significantly contributes to the limited scientific literature on HCW experiences responding to COVID-19 across the Pacific. Recommendations arising out of this research align with consensus priorities and standards that were identified pre-pandemic by health stakeholders across the Pacific for enhancing EC system development. With limited HCWs available for many Pacific nations, it is imperative the dignity and welfare of local HCWs is genuinely prioritised. Funding: Epidemic Ethics/WHO, Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Co-funding: Australasian College for Emergency Medicine Foundation, International Development Fund Grant.

9.
Lancet Reg Health West Pac ; 25: 100519, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35822061

RESUMEN

The COVID-19 pandemic continues to test health systems resilience worldwide. Low- and middle-income country (LMIC) health care systems have considerable experience in disasters and disease outbreaks. Lessons from the preparedness and responses to COVID-19 in LMICs may be valuable to other countries.This policy paper synthesises findings from a multiphase qualitative research project, conducted during the pandemic to document experiences of Pacific Island Country and Territory (PICT) frontline clinicians and emergency care (EC) stakeholders. Thematic analysis and synthesis of enablers related to each of the Pacific EC systems building blocks identified key factors contributing to strengthened EC systems.Effective health system responses to the COVID-19 pandemic occurred when frontline clinicians and 'decision makers' collaborated with respect and open communication, overcoming healthcare workers' fear and discontent. PICT EC clinicians demonstrated natural leadership and strengthened local EC systems, supporting essential healthcare. Despite resource limitations, PICT cultural strengths of relational connection and innovation ensured health system resilience. COVID-19 significantly disrupted services, with long-tail impacts on non-communicable disease and other health burdens.Lessons learned in responding to COVID-19 can be applied to ongoing health system strengthening initiatives. Optimal systems improvement and sustainability requires EC leaders' involvement in current decision-making as well as future planning. Search strategy and selection criteria: Search strategy and selection criteria We searched PubMed, Google Scholar, Ovid, WHO resources, Pacific and grey literature using search terms 'emergency care', 'acute/critical care', 'health care workers', 'emergency care systems/health systems', 'health system building blocks', 'COVID-19', 'pandemic/surge event/disease outbreaks' 'Low- and Middle-Income Countries', 'Pacific Islands/region' and related terms. Only English-language articles were included. Funding: Phases 1 and 2A of this study were part of an Epidemic Ethics/World Health Organization (WHO) initiative, supported by Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Copyright of the original work on which this publication is based belongs to WHO. The authors have been given permission to publish this manuscript. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the views, decisions or policies of WHO. Co-funding for this research was received from the Australasian College for Emergency Medicine Foundation via an International Development Fund Grant. RM is supported by a National Health and Medical Research Council (NHMRC) Postgraduate Scholarship and a Monash Graduate Excellence Scholarship. GOR is supported by a NHMRC Early Career Research Fellowship. CEB is supported by a University of Queensland Development Research Fellowship. None of these funders played any role in study design, results analysis or manuscript preparation.

10.
Cancer Res ; 82(10): 1858-1869, 2022 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-35298624

RESUMEN

Antibody-drug conjugates (ADC) have emerged as one of the pillars of clinical disease management in oncology. The biggest hurdle to widespread development and application of ADCs has been a narrow therapeutic index. Advances in antibody technologies and formats as well as novel linker and payload chemistries have begun to facilitate structural improvements to ADCs. However, the interplay of structural characteristics with physiologic and pharmacologic factors determining therapeutic success has garnered less attention. This review elaborates on the pharmacology of ADCs, the pathophysiology of cancerous tissues, and the reciprocal consequences on ADC properties and functions. While most currently approved ADCs utilize either microtubule inhibition or DNA damage as primary mechanisms of action, we present arguments to expand this repertoire and highlight the need for payload mechanisms that exploit disease-specific vulnerabilities. We promote the idea that the choice of antibody format, targeting antigen, linker properties, and payload of an ADC should be deliberately fit for purpose by taking the pathophysiology of disease and the specific pharmacology of the drug entity into account, thus allowing a higher probability of clinical success.


Asunto(s)
Antineoplásicos , Inmunoconjugados , Neoplasias , Anticuerpos/uso terapéutico , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Humanos , Inmunoconjugados/química , Inmunoconjugados/farmacología , Inmunoconjugados/uso terapéutico , Neoplasias/tratamiento farmacológico
11.
Sci Rep ; 11(1): 18571, 2021 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-34535719

RESUMEN

The current standard preclinical oncology models are not able to fully recapitulate therapeutic targets and clinically relevant disease biology, evidenced by the 90% attrition rate of new therapies in clinical trials. Three-dimensional (3D) culture systems have the potential to enhance the relevance of preclinical models. However, the limitations of currently available cellular assays to accurately evaluate therapeutic efficacy in these models are hindering their widespread adoption. We assessed the compatibility of the lactate dehydrogenase (LDH) assay in 3D spheroid cultures against other commercially available readout methods. We developed a standardized protocol to apply the LDH assay to ex vivo cultures, considering the impact of culture growth dynamics. We show that accounting for growth rates and background release levels of LDH are sufficient to make the LDH assay a suitable methodology for longitudinal monitoring and endpoint assessment of therapeutic efficacy in both cell line-derived xenografts (xenospheres) and patient-derived explant cultures. This method has the added value of being non-destructive and not dependent on reagent penetration or manipulation of the parent material. The establishment of reliable readout methods for complex 3D culture systems will further the utility of these tumor models in preclinical and co-clinical drug development studies.


Asunto(s)
Ensayos de Selección de Medicamentos Antitumorales/métodos , L-Lactato Deshidrogenasa/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Descubrimiento de Drogas/métodos , Humanos , Ratones , Esferoides Celulares/efectos de los fármacos , Esferoides Celulares/metabolismo , Células Tumorales Cultivadas
12.
JBMR Plus ; 5(9): e10530, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34532615

RESUMEN

Osteogenesis imperfecta (OI), is a genetic disorder of bone fragility caused by mutations in collagen I or proteins involved in collagen processing. Previous studies in mice and human OI bones have shown that excessive activation of TGF-ß signaling plays an important role in dominant and recessive OI disease progression. Inhibition of TGF-ß signaling with a murine pan-specific TGF-ß neutralizing antibody (1D11) was shown to significantly increase trabecular bone volume and long bone strength in mouse models of OI. To investigate the frequency of dosing and dose options of TGF-ß neutralizing antibody therapy, we assessed the effect of 1D11 on disease progression in a dominant OI mouse model (col1a2 gene mutation at G610C). In comparison with OI mice treated with a control antibody, we attempted to define mechanistic effects of 1D11 measured via µCT, biomechanical, dynamic histomorphometry, and serum biomarkers of bone turnover. In addition, osteoblast and osteoclast numbers in histological bone sections were assessed to better understand the mechanism of action of the 1D11 antibody in OI. Here we show that 1D11 treatment resulted in both dose and frequency dependency, increases in trabecular bone volume fraction and ultimate force in lumbar bone, and ultimate force, bending strength, yield force, and yield strength in the femur (p ≤ 0.05). Suppression of serum biomarkers of osteoblast differentiation, osteocalcin, resorption, CTx-1, and bone formation were observed after 1D11 treatment of OI mice. Immunohistochemical analysis showed dose and frequency dependent decreases in runt-related transcription factor, and increase in alkaline phosphatase in lumbar bone sections. In addition, a significant decrease in TRACP and the number of osteoclasts to bone surface area was observed with 1D11 treatment. Our results show that inhibition of the TGF-ß pathway corrects the high-turnover aspects of bone disease and improves biomechanical properties of OI mice. These results highlight the potential for a novel treatment for osteogenesis imperfecta. © 2021 Sanofi-Genzyme. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

13.
Environ Toxicol Chem ; 40(9): 2615-2628, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34171144

RESUMEN

The occurrence of some species listed under the United States' Endangered Species Act in agricultural landscapes suggests that their habitats could potentially be exposed to pesticides. However, the potential effects from such exposures on populations are difficult to estimate. Mechanistic models can provide an avenue to estimating the potential impacts on populations, considering realistic assumptions about the ecology of the species, the ecosystem it is part of, and the potential exposures within the habitat. In the present study, we applied a hybrid model of the Topeka shiner (Notropis topeka), a small endangered cyprinid fish endemic to the US Midwest, to assess the potential population-level effects of realistic exposures to a fungicide (benzovindiflupyr). The Topeka shiner populations were simulated in the context of the food web found in oxbow habitats that are the focus of ongoing habitat restoration efforts for the species. We applied realistic, time-variable exposure scenarios and represented lethal and sublethal effects to individual Topeka shiners using toxicokinetic-toxicodynamic models. With fish in general showing the highest sensitivity to the compound, direct effects on simulated Topeka shiner populations governed the population-level effects. We characterized the population-level effects of different exposure scenarios with exposure multiplication factors (EMFs) applied. The introduction of a vegetative filter strip (VFS; 15 ft; 4.6 m) between the treated area and the oxbow habitat was shown to be effective as mitigation because EMFs were 2 to 3 times higher than for the exposure scenario without VFS. Environ Toxicol Chem 2021;40:2615-2628. © 2021 SETAC.


Asunto(s)
Cyprinidae , Plaguicidas , Animales , Ecosistema , Especies en Peligro de Extinción , Cadena Alimentaria , Plaguicidas/toxicidad , Estados Unidos
14.
Afr J Emerg Med ; 10(Suppl 1): S56-S59, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33318903

RESUMEN

Emergency Medicine (EM) development is established worldwide and fast developing in Sub-Saharan Africa. Medical specialty development requires multiple human resources and logistics which are frequently not available in LMICs. This article describes an innovative hybrid EM specialization program in Botswana that involved partnership with a neighbouring country in Sub-Saharan Africa. Many initial problems challenged its development, but significant local and regional support led to success. Botswana graduated its first three EM specialists in 2018 and now has an ongoing and sustainable EM program. This regional partnership resulted in numerous academic, research and clinical EM developments for Botswana and SA. UB-UCT EM training Partnership Model is a novel and sustainable cross- African collaboration with significant benefits for both health systems as well as for the individual trainees. This hybrid arrangement should be considered by other LMICs looking for EM specialty training and development.

16.
Methods ; 180: 45-55, 2020 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-32387313

RESUMEN

Biological nanoparticles include liposomes, extracellular vesicle and lipid-based discoidal systems. When studying such particles, there are several key parameters of interest, including particle size and concentration. Measuring these characteristics can be of particular importance in the research laboratory or when producing such particles as biotherapeutics. This article briefly describes the major types of lipid-containing nanoparticles and the techniques that can be used to study them. Such methodologies include electron microscopy, atomic force microscopy, dynamic light scattering, nanoparticle tracking analysis, flow cytometry, tunable resistive pulse sensing and microfluidic resistive pulse sensing. Whilst no technique is perfect for the analysis of all nanoparticles, this article provides advantages and disadvantages of each, highlighting the latest developments in the field. Finally, we demonstrate the use of microfluidic resistive pulse sensing for the analysis of biological nanoparticles.


Asunto(s)
Biofisica/métodos , Lípidos/análisis , Liposomas/análisis , Nanopartículas/análisis , Dispersión Dinámica de Luz , Vesículas Extracelulares , Citometría de Flujo/métodos , Lípidos/química , Liposomas/química , Microfluídica/métodos , Microscopía de Fuerza Atómica , Microscopía Electrónica , Nanopartículas/química , Tamaño de la Partícula
17.
Int J Mol Sci ; 21(3)2020 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-31979415

RESUMEN

ABCG2 is one of a triumvirate of human multidrug ATP binding cassette (ABC) transporters that are implicated in the defense of cells and tissues against cytotoxic chemicals, but these transporters can also confer chemotherapy resistance states in oncology. Understanding the mechanism of ABCG2 is thus imperative if we are to be able to counter its deleterious activity. The structure of ABCG2 and its related family members (ABCG5/G8) demonstrated that there were two interfaces between the nucleotide binding domains (NBD). In addition to the canonical ATP "sandwich-dimer" interface, there was a second contact region between residues at the C-terminus of the NBD. We investigated this second interface by making mutations to a series of residues that are in close interaction with the opposite NBD. Mutated ABCG2 isoforms were expressed in human embryonic kidney (HEK) 293T cells and analysed for targeting to the membrane, drug transport, and ATPase activity. Mutations to this second interface had a number of effects on ABCG2, including altered drug specificity, altered drug transport, and, in two mutants, a loss of ATPase activity. The results demonstrate that this region is particularly sensitive to mutation and can impact not only direct, local NBD events (i.e., ATP hydrolysis) but also the allosteric communication to the transmembrane domains and drug transport.


Asunto(s)
Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/química , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/metabolismo , Adenosina Trifosfato/metabolismo , Preparaciones Farmacéuticas/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/antagonistas & inhibidores , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Adenosina Trifosfatasas/antagonistas & inhibidores , Adenosina Trifosfatasas/metabolismo , Animales , Transporte Biológico/genética , Embrión de Pollo , Clorofila/análogos & derivados , Clorofila/metabolismo , Resistencia a Múltiples Medicamentos/genética , Células HEK293 , Humanos , Hidrólisis , Mitoxantrona/metabolismo , Mutación , Dominios Proteicos/genética , Inhibidores de Topoisomerasa II/metabolismo
18.
ACS Biomater Sci Eng ; 5(3): 1544-1552, 2019 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-31799379

RESUMEN

Personalized cancer medicine offers the promise of more effective treatments that are tailored to an individual's own dynamic cancer phenotype. Meanwhile, tissue-engineering approaches to modeling tumors may complement these advances by providing a powerful new approach to understanding the adaptation dynamics occurring during treatment. However, in both of these areas new tools will be required to gain a full picture of the genetic and epigenetic regulators of phenotype dynamics occurring in the small populations of cells that drive resistance. In this study, we perform epigenomic analysis of brain tumor cells that are collected from micro-engineered three-dimensional tumor models, overcoming the challenges associated with the small numbers of cells contained within these micro-tissue niches, in this case collecting ~1,000 cells per sample. Specifically, we use a high-resolution epigenomic analysis method known as microfluidic-oscillatory-washing-based chromatin immunoprecipitation with sequencing (MOWChIP-seq) to analyze histone methylation patterns (H3K4me3). We identified gene loci that are associated with the H3K4me3 modification, which is generally a mark of active transcription. We compared methylation patterns in standard 2D cultures and 3D cultures based on type I collagen hydrogels, under both normoxic and hypoxic conditions. We found that culture dimensionality drastically impacted the H3k4me3 profile and resulted in differential modifications in response to hypoxic stress. Differentially H3K4me3-marked regions under the culture conditions used in this study have important implications for gene expression differences that have been previously observed. In total, our work illustrates a direct connection between cell culture or tissue niche condition and genome-wide alterations in histone modifications, providing the first steps towards analyzing the spatiotemporal variations in epigenetic regulation of cancer cell phenotypes. This study, to our knowledge, also represents the first time broad-spectrum epigenomic analysis has been applied to small cell samples collected from engineered micro-tissues.

19.
Afr J Prim Health Care Fam Med ; 11(1): e1-e7, 2019 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-31714118

RESUMEN

INTRODUCTION: Successful cardiopulmonary resuscitation (CPR) relies, in part, on the availability and the correct functioning of resuscitation equipment. These data are often lacking in resource-constrained African settings. AIM: To assess the availability and the functional status of CPR equipment in resuscitation trolleys at district hospitals in Botswana. SETTING: The study was conducted across four district hospitals in Botswana. METHODS: A cross-sectional study was conducted using a checklist adopted following the Emergency Medical Services of South Africa (EMSSA) guidelines, modified and contextualised to Botswana. RESULTS: All the four district hospitals had inadequate number of CPR equipment available in the resuscitation trolleys. The overall availability of drugs and equipment ranged from 19% to 31.1%. Availability of equipment needed for maintaining circulation and fluids ranged from 27% to 49%, while availability of items for airway and breathing ranged from 9.2% to 24.1%. The overall availability of essential drugs for resuscitation was only 20.4%, and in some wards expired drugs were kept in the trolley. Out of 40 wards that participated in the study, only 10 kept CPR algorithms in the resuscitation trolley. The resuscitation trolley was checked on a daily basis only in the critical care units. CONCLUSION: The resuscitation trolleys were not maintained as per standards. Failure to improve the existing situation could negatively impact the outcome of CPR. Evidence-based standard checklists for resuscitation trolleys need to be enforced to improve the quality of CPR provision in district hospitals in Botswana.


Asunto(s)
Reanimación Cardiopulmonar/instrumentación , Equipos y Suministros de Hospitales , Hospitales de Distrito/organización & administración , Botswana , Estudios Transversales , Servicio de Urgencia en Hospital/organización & administración , Equipos y Suministros de Hospitales/normas , Equipos y Suministros de Hospitales/provisión & distribución , Paro Cardíaco/terapia , Humanos
20.
J Sports Sci Med ; 18(3): 544-551, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31427877

RESUMEN

Currently there are recommendations for stretching type, repetitions and duration within a training session to improve flexibility. It is, however, unclear whether multiple daily stretch training sessions provide greater flexibility than single daily sessions. The objective was to investigate the effectiveness of single (1×day) versus twice daily (2×day) unilateral stretch training sessions on hip flexion range of motion (ROM), agonist and antagonist force and jump performance of the stretched and contralateral, non-stretched legs. Groups included a control, 1×day and 2×day stretch training groups. Static stretching (SS) involved self-administered (stretch band), unilateral, hamstrings and quadriceps stretching for 2-weeks. Pre- and post-testing involved hip flexion ROM, knee extension and flexion maximal voluntary isometric contraction (MVIC) forces and unilateral drop jumps (DJ). The 2×day group showed a 12.8% (p = 0.08) greater active ROM versus Control. The 1×day group showed a 7.5% (p=0.1) ballistic ROM increase with no significant changes with the 2×day and Control groups. The stretched leg experienced a 5.01% (p = 0.1) hip flexion ballistic ROM increase contrasting with a 2.3% increase for the contralateral leg. Twice daily training provided 7.1% (p = 0.07) and 6.6% (p = 0.01) quadriceps MVC force increases of the stretched trained and contralateral legs respectively. Contralateral DJ height improved 22.6% (p = 0.002) with 2×day training. In conclusion, 1xday and 2×day stretch training tended to improved ballistic and active ROM respectively, whereas 2×day training improved MVIC force and DJ height. The findings may apply to fitness enthusiasts and rehabilitation as unilateral stretching may retain performance and active ROM of the stretched and contralateral limbs.


Asunto(s)
Músculos Isquiosurales/fisiología , Articulación de la Cadera/fisiología , Ejercicios de Estiramiento Muscular/métodos , Músculo Cuádriceps/fisiología , Femenino , Humanos , Articulación de la Rodilla/fisiología , Masculino , Ejercicio Pliométrico , Rango del Movimiento Articular , Factores de Tiempo , Adulto Joven
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