Copper-67-Labeled Bombesin Peptide for Targeted Radionuclide Therapy of Prostate Cancer.

The gastrin-releasing peptide receptor (GRPR) is a promising molecular target for imaging and therapy of prostate cancer using bombesin peptides that bind to the receptor with high affinity. Targeted copper theranostics (TCTs) using copper radionuclides, 64Cu for imaging and 67Cu for therapy, offer significant advantages in the development of next-generation theranostics. [64Cu]Cu-SAR-BBN is in clinical development for PET imaging of GRPR-expressing cancers. This study explores the therapeutic efficacy of [67Cu]Cu-SAR-BBN in a pre-clinical mouse model. The peptide was radiolabeled with 67Cu, and specific binding of the radiolabeled peptide towards GRPR-positive PC-3 prostate cancer cells was confirmed with 52.2 ± 1.4% total bound compared to 5.8 ± 0.1% with blocking. A therapy study with [67Cu]Cu-SAR-BBN was conducted in mice bearing PC-3 tumors by injecting 24 MBq doses a total of six times. Tumor growth was inhibited by 93.3% compared to the control group on day 19, and median survival increased from 34.5 days for the control group to greater than 54 days for the treatment group. The ease and stability of the radiochemistry, favorable biodistribution, and the positive tumor inhibition demonstrate the suitability of this copper-based theranostic agent for clinical assessment in the treatment of cancers expressing GRPR.

Detection and therapy of neuroblastoma minimal residual disease using [64/67Cu]Cu-SARTATE in a preclinical model of hepatic metastases.

BACKGROUND: A major challenge to the long-term success of neuroblastoma therapy is widespread metastases that survive initial therapy as minimal residual disease (MRD). The SSTR2 receptor is expressed by most neuroblastoma tumors making it an attractive target for molecularly targeted radionuclide therapy. SARTATE consists of octreotate, which targets the SSTR2 receptor, conjugated to MeCOSar, a bifunctional chelator with high affinity for copper. Cu-SARTATE offers the potential to both detect and treat neuroblastoma MRD by using [64Cu]Cu-SARTATE to detect and monitor the disease and [67Cu]Cu-SARTATE as the companion therapeutic agent. In the present study, we tested this theranostic pair in a preclinical model of neuroblastoma MRD. An intrahepatic model of metastatic neuroblastoma was established using IMR32 cells in nude mice. The biodistribution of [64Cu]Cu-SARTATE was measured using small-animal PET and ex vivo tissue analysis. Survival studies were carried out using the same model: mice (6-8 mice/group) were given single doses of saline, or 9.25 MBq (250 µCi), or 18.5 MBq (500 µCi) of [67Cu]Cu-SARTATE at either 2 or 4 weeks after tumor cell inoculation. RESULTS: PET imaging and ex vivo biodistribution confirmed tumor uptake of [64Cu]Cu-SARTATE and rapid clearance from other tissues. The major clearance tissues were the kidneys (15.6 ± 5.8% IA/g at 24 h post-injection, 11.5 ± 2.8% IA/g at 48 h, n = 3/4). Autoradiography and histological analysis confirmed [64Cu]Cu-SARTATE uptake in viable, SSTR2-positive tumor regions with mean tumor uptakes of 14.1-25.0% IA/g at 24 h. [67Cu]Cu-SARTATE therapy was effective when started 2 weeks after tumor cell inoculation, extending survival by an average of 13 days (30%) compared with the untreated group (mean survival of control group 43.0 ± 8.1 days vs. 55.6 ± 9.1 days for the treated group; p = 0.012). No significant therapeutic effect was observed when [67Cu]Cu-SARTATE was started 4 weeks after tumor cell inoculation, when the tumors would have been larger (control group 14.6 ± 8.5 days; 9.25 MBq group 9.5 ± 1.6 days; 18.5 MBq group 15.6 ± 4.1 days; p = 0.064). CONCLUSIONS: Clinical experiences of peptide-receptor radionuclide therapy for metastatic disease have been encouraging. This study demonstrates the potential for a theranostic approach using [64/67Cu]Cu-SARTATE for the detection and treatment of SSTR2-positive neuroblastoma MRD.

Therapeutic Efficacy of a Bivalent Inhibitor of Prostate-Specific Membrane Antigen Labeled with 67Cu.

Radionuclide therapy targeting prostate-specific membrane antigen (PSMA) is promising for prostate cancer. We previously reported a ligand, 64Cu-CuSarbisPSMA, featuring 2 lysine-ureido-glutamate groups. Here, we report the therapeutic potential of 67Cu-CuSarbisPSMA. Methods: Growth of PSMA-positive xenografts was evaluated after treatment with 67Cu-CuSarbisPSMA or 177Lu-LuPSMA imaging and therapy (I&T). Results: At 13 d after injection, tumor growth was similarly inhibited by the 2 tracers in a dose-dependent manner. Survival was comparable after single (30 MBq) or fractionated (2 × 15 MBq, 2 wk apart) administrations. Conclusion:67Cu-CuSarbisPSMA is efficacious in a PSMA-expressing model of prostate cancer.

IAEA contribution to the development of 64Cu radiopharmaceuticals for theranostic applications.

Copper-64 is a very attractive radioisotope with unique nuclear properties that allow using it as both a diagnostic and therapeutic agent, thus providing an almost ideal example of a theranostic radionuclide. A characteristic of Cu-64 stems from the intrinsic biological nature of copper ions that play a fundamental role in a large number of cellular processes. Cu-64 is a radionuclide that reflects the natural biochemical pathways of Cu-64 ions, therefore, can be exploited for the detection and therapy of certain malignancies and metabolic diseases. Beside these applications of Cu-64 ions, this radionuclide can be also used for radiolabelling bifunctional chelators carrying a variety of pharmacophores for targeting different biological substrates. These include peptide-based substrates and immunoconjugates as well as small-molecule bioactive moieties. Fueled by the growing interest of Member States (MS) belonging to the International Atomic Energy Agency (IAEA) community, a dedicated Coordinated Research Project (CRP) was initiated in 2016, which recruited thirteen participating MS from four continents. Research activities and collaborations between the participating countries allowed for collection of an impressive series of results, particularly on the production, preclinical evaluation and, in a few cases, clinical evaluation of various 64Cu-radiopharmaceuticals that may have potential impact on future development of the field. Since this CRP was finalized at the beginning of 2020, this short review summarizes outcomes, outputs and results of this project with the purpose to propagate to other MS and to the whole scientific community, some of the most recent achievements on this novel class of theranostic 64Cu-pharmaceuticals.

Peptide Receptor Radionuclide Therapy with 67Cu-CuSarTATE Is Highly Efficacious Against a Somatostatin-Positive Neuroendocrine Tumor Model.

Peptide receptor radionuclide therapy (PRRT) using radiolabeled octreotate is an effective treatment for somatostatin receptor 2-expressing neuroendocrine tumors. The diagnostic and therapeutic potential of 64Cu and 67Cu, respectively, offers the possibility of using a single somatostatin receptor-targeted peptide conjugate as a theranostic agent. A sarcophagine cage amine ligand, MeCOSar (5-(8-methyl-3,6,10,13,16,19-hexaaza-bicyclo[6.6.6]icosan-1-ylamino)-5-oxopentanoic acid), conjugated to (Tyr3)-octreotate, called 64Cu-CuSarTATE, was demonstrated to be an imaging agent and potential prospective dosimetry tool in 10 patients with neuroendocrine tumors. This study aimed to explore the antitumor efficacy of 67Cu-CuSarTATE in a preclinical model of neuroendocrine tumors and compare it with the standard PRRT agent, 177Lu-LuDOTA-Tyr3-octreotate (177Lu-LuTATE). Methods: The antitumor efficacy of various doses of 67Cu-CuSarTATE in AR42J (rat pancreatic exocrine) tumor-bearing mice was compared with 177Lu-LuTATE. Results: Seven days after a single administration of 67Cu-CuSarTATE (5 MBq), tumor growth was inhibited by 75% compared with vehicle control. Administration of 177Lu-LuTATE (5 MBq) inhibited tumor growth by 89%. Survival was extended from 12 d in the control group to 21 d after treatment with both 67Cu-CuSarTATE and 177Lu-LuTATE. In a second study, the efficacy of fractionated delivery of PRRT was assessed, comparing the efficacy of 30 MBq of 67Cu-CuSarTATE or 177Lu-LuTATE, either as a single intravenous injection or as two 15-MBq fractions 2 wk apart. Treatment of tumors with 2 fractions significantly improved survival over delivery as a single fraction (67Cu-CuSarTATE: 47 vs. 36 d [P = 0.036]; 177Lu-LuTATE: 46 vs. 29 d [P = 0.040]). Conclusion: This study demonstrates that 67Cu-CuSarTATE is well tolerated in BALB/c nude mice and highly efficacious against AR42J tumors in vivo. Administration of 67Cu-CuSarTATE and 177Lu-LuTATE divided into 2 fractions over 2 wk was more efficacious than administration of a single fraction. The antitumor activity of 67Cu-CuSarTATE in the AR42J tumor model demonstrated the suitability of this novel agent for clinical assessment in the treatment of somatostatin receptor 2-expressing neuroendocrine tumors.

National Cancer Institute (NCI) Program for Natural Products Discovery: Rapid Isolation and Identification of Biologically Active Natural Products from the NCI Prefractionated Library.

An automated, high-capacity, and high-throughput procedure for the rapid isolation and identification of biologically active natural products from a prefractionated library is presented. The semipreparative HPLC method uses 1 mg of the primary hit fraction and produces 22 subfractions in an assay-ready format. Following screening, all active fractions are analyzed by NMR, LCMS, and FTIR, and the active principle structural classes are elucidated. In the proof-of-concept study, we show the processes involved in generating the subfractions, the throughput of the structural elucidation work, as well as the ability to rapidly isolate and identify new and biologically active natural products. Overall, the rapid second-stage purification conserves extract mass, requires much less chemist time, and introduces knowledge of structure early in the isolation workflow.

The NCI library of traditional Chinese medicinal plant extracts - Preliminary assessment of the NCI-60 activity and chemical profiling of selected species.

Botanical-based natural products are an important resource for medicinal drug discovery and continue to provide diverse pharmacophores with therapeutic potential against cancer and other human diseases. A prototype Traditional Chinese Medicine (TCM) plant extract library has been established at the US National Cancer Institute, which contains both the organic and aqueous extracts of 132 authenticated medicinal plant species that collectively represent the potential therapeutic contents of most commonly used TCM herbal prescriptions. This library is publicly available in 96- and 384- well plates for high throughput screening across a broad array of biological targets, as well as in larger quantities for isolation of active chemical ingredients. Herein, we present the methodology used to generate the library and the preliminary assessment of the anti-proliferative activity of this crude extract library in NCI-60 human cancer cell lines screen. Particularly, we report the chemical profiling and metabolome comparison analysis of four commonly used TCM plants, namely Brucea javanica, Dioscorea nipponica, Cynanchum atratum, and Salvia miltiorrhiza. Bioassay-guided isolation resulted in the identification of the active compounds, and different extraction methods were compared for their abilities to extract cytotoxic compounds and to concentrate biologically active natural products.

Perceptions and evaluations of front-line health workers regarding the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ): a mixed-method approach.

Although it is well known that a successful implementation depends on the front-liners' knowledge and participation, as well as on the organizational capacity of the institutions involved, we still know little about how front-line health workers have been involved in the implementation of the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ). This paper develops a contingent mixed-method approach to explore the perceptions of front-line health workers - managers, nurses, community health workers, and doctors - regarding the PMAQ (2nd round), and their evaluations concerning health unit organizational capacity. The research is guided by three relevant inter-related concepts from implementation theory: policy knowledge, participation, and organizational capacity. One hundred and twenty-seven health workers from 12 primary health care units in Goiânia, Goiás State, Brazil, answered semi-structured questionnaires, seeking to collect data on reasons for adherence, forms of participation, perceived impact (open-ended questions), and evaluation of organizational capacity (score between 0-10). Content analyses of qualitative data enabled us to categorize the variables "level of perceived impact of PMAQ" and "reasons for adhering to PMAQ". The calculation and aggregation of the means for the scores given for organizational capacity enabled us to classify distinct levels of organizational capacity. We finally integrated both variables (Perceived-Impact and Organizational-Capacity) through cross-tabulation and the narrative. Results show that nurses are the main type of professional participating. The low organizational capacity and little policy knowledge affected workers participation in and their perceptions of the PMAQ.

Perceptions and evaluations of front-line health workers regarding the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ): a mixed-method approach / As percepções e avaliações dos profissionais de saúde que trabalham na ponta em relação ao Programa Nacional de Melhoria do Acesso e da Qualidade da Atenção Básica (PMAQ): uma abordagem com métodos mistos / Percepciones y evaluaciones de los trabajadores de salud de primera línea, en relación con el Programa Nacional de Mejora del Acceso y Calidad de la Atención Básica (PMAQ): un enfoque metodológico mixto

Abstract: Although it is well known that a successful implementation depends on the front-liners' knowledge and participation, as well as on the organizational capacity of the institutions involved, we still know little about how front-line health workers have been involved in the implementation of the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ). This paper develops a contingent mixed-method approach to explore the perceptions of front-line health workers - managers, nurses, community health workers, and doctors - regarding the PMAQ (2nd round), and their evaluations concerning health unit organizational capacity. The research is guided by three relevant inter-related concepts from implementation theory: policy knowledge, participation, and organizational capacity. One hundred and twenty-seven health workers from 12 primary health care units in Goiânia, Goiás State, Brazil, answered semi-structured questionnaires, seeking to collect data on reasons for adherence, forms of participation, perceived impact (open-ended questions), and evaluation of organizational capacity (score between 0-10). Content analyses of qualitative data enabled us to categorize the variables "level of perceived impact of PMAQ" and "reasons for adhering to PMAQ". The calculation and aggregation of the means for the scores given for organizational capacity enabled us to classify distinct levels of organizational capacity. We finally integrated both variables (Perceived-Impact and Organizational-Capacity) through cross-tabulation and the narrative. Results show that nurses are the main type of professional participating. The low organizational capacity and little policy knowledge affected workers participation in and their perceptions of the PMAQ.

Resumo: Sabe-se que a implementação bem-sucedida de um programa depende do conhecimento e da participação dos profissionais que trabalham na ponta, além da capacidade organizacional das instituições envolvidas. No entanto, ainda sabemos pouco sobre o envolvimento desses profissionais na implementação do Programa Nacional de Melhoria do Acesso e da Qualidade da Atenção Básica (PMAQ). O artigo desenvolve uma abordagem de métodos mistos de tipo contingente para explorar as percepções dos profissionais de saúde na ponta - gestores locais, enfermeiros, agentes comunitários de saúde e médicos - sobre o segundo ciclo do PMAQ, além de relacionar essas percepções às avaliações a respeito da capacidade organizacional da unidade de saúde. O estudo é orientado por três conceitos inter-relacionados e relevantes da teoria da implementação: conhecimento das políticas, participação e capacidade organizacional. Cento e vinte e sete profissionais de saúde de 12 unidades de atenção primária em Goiânia, Goiás, Brasil, responderam questionários semiestruturados, buscando coletar dados sobre os motivos pela adesão, formas de participação, impacto percebido (perguntas abertas) e avaliação da capacidade organizacional (pontuações de 0 a 10). As análises de conteúdo dos dados qualitativos permitiram categorizar as variáveis "nível percebido de impacto do PMAQ" e "motivos pela adesão ao PMAQ". Os cálculos e agregação da média das pontuações para capacidade organizacional permitiram classificar os diferentes níveis dessa capacidade. Finalmente, foram integradas as duas variáveis (Impacto Percebido e Capacidade Organizacional) através da tabulação cruzada e da narrativa. Os resultados mostram que os enfermeiros são o principal tipo de profissional que participa no programa. A baixa capacidade organizacional e o conhecimento limitado da política afetaram a participação dos professionais de saúde e suas percepções em relação ao PMAQ.

Resumen: Pese a que es bien sabido que una implementación exitosa depende del conocimiento y participación de los trabajadores de salud de primera línea, así como la capacidad organizativa de las instituciones involucradas, todavía sabemos poco sobre cómo los trabajadores de salud en primera línea de atención han sido involucrados en la implementación del Programa Nacional de Mejora del Acceso y Calidad de la Atención Básica (PMAQ) brasileño. Este trabajo desarrolla un enfoque metodológico mixto aleatorio para investigar las percepciones de los trabajadores de primera línea de la salud -gestores, enfermeras, trabajadores comunitarios de cuidados de salud, y doctores- en relación con el PMAQ (segunda fase), y asociarlos con sus evaluaciones respecto a la capacidad organizativa de las unidades de salud. La investigación está guiada por tres conceptos relevantes interrelacionados, provenientes de la teoría de la implementación: política de conocimiento, participación, y capacidad organizativa. Ciento veintisiete trabajadores de salud, procedentes de 12 unidades de atención primaria de salud en Goiânia, respondieron a cuestionarios semiestructurados, buscando recoger datos sobre: adherencia, formas de participación, impacto percibido (preguntas de final abierto), y evaluación de la capacidad organizativa (notas entre 0-10). El contenido de los análisis cualitativos de datos nos permitió categorizar las variables "nivel del impacto percibido de PMAQ" y "razones de adherencia al PMAQ". El cálculo y agregación de medios para los marcadores proporcionados, respecto a la capacidad organizativa, nos permitieron clasificar los distintos niveles de la misma. Integramos, finalmente, ambas variables (Impacto Percibido y Capacidad Organizativa) mediante tabulación cruzada y narrativa. Los resultados muestran que las enfermeras son la mayor parte de las profesionales que participan. La baja capacidad organizativa y el escaso conocimiento sobre las políticas que deben ser implementadas afectó a la participación y sus percepciones sobre el PMAQ.

NCI Program for Natural Product Discovery: A Publicly-Accessible Library of Natural Product Fractions for High-Throughput Screening.

The US National Cancer Institute's (NCI) Natural Product Repository is one of the world's largest, most diverse collections of natural products containing over 230,000 unique extracts derived from plant, marine, and microbial organisms that have been collected from biodiverse regions throughout the world. Importantly, this national resource is available to the research community for the screening of extracts and the isolation of bioactive natural products. However, despite the success of natural products in drug discovery, compatibility issues that make extracts challenging for liquid handling systems, extended timelines that complicate natural product-based drug discovery efforts and the presence of pan-assay interfering compounds have reduced enthusiasm for the high-throughput screening (HTS) of crude natural product extract libraries in targeted assay systems. To address these limitations, the NCI Program for Natural Product Discovery (NPNPD), a newly launched, national program to advance natural product discovery technologies and facilitate the discovery of structurally defined, validated lead molecules ready for translation will create a prefractionated library from over 125,000 natural product extracts with the aim of producing a publicly-accessible, HTS-amenable library of >1,000,000 fractions. This library, representing perhaps the largest accumulation of natural-product based fractions in the world, will be made available free of charge in 384-well plates for screening against all disease states in an effort to reinvigorate natural product-based drug discovery.

Structural model of human dUTPase in complex with a novel proteinaceous inhibitor.

Human deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase), essential for DNA integrity, acts as a survival factor for tumor cells and is a target for cancer chemotherapy. Here we report that the Staphylococcal repressor protein StlSaPIBov1 (Stl) forms strong complex with human dUTPase. Functional analysis reveals that this interaction results in significant reduction of both dUTPase enzymatic activity and DNA binding capability of Stl. We conducted structural studies to understand the mechanism of this mutual inhibition. Small-angle X-ray scattering (SAXS) complemented with hydrogen-deuterium exchange mass spectrometry (HDX-MS) data allowed us to obtain 3D structural models comprising a trimeric dUTPase complexed with separate Stl monomers. These models thus reveal that upon dUTPase-Stl complex formation the functional homodimer of Stl repressor dissociates, which abolishes the DNA binding ability of the protein. Active site forming dUTPase segments were directly identified to be involved in the dUTPase-Stl interaction by HDX-MS, explaining the loss of dUTPase activity upon complexation. Our results provide key novel structural insights that pave the way for further applications of the first potent proteinaceous inhibitor of human dUTPase.

The politics of implementing a performance measurement program (PMAQ) at the front line of primary health care in Goiania, Brazil: a qualitative political analysis

We develop a political policy analysis to understand how front line health workers in Goiania evaluate the Brazilian NationalProgram for Improving Access and Quality of Primary Care (PMAQ). We interviewed 25 front liners, including doctors, nurses, community health agents and local managers. Analysis was based on political themes highlighted by the public policy/implementation and performance measurement political literature. We explored seven key themes: adherence, organizational capacity, participation, alternative logics, feedback, perceived impact and culture of assessment. Results show the need to deconstruct rhetoric/ambiguities on the front line of implementation, by means of fostering organizational capacity, knowledge, participation and policy feedback.

Online data on opening hours of general practices in England: a comparison with telephone survey data.

BACKGROUND: The NHS Choices website (www.nhs.uk) provides data on the opening hours of general practices in England. If the data are accurate, they could be used to examine the benefits of extended hours. AIM: To determine whether online data on the opening times of general practices in England are accurate regarding the number of hours in which GPs provide face-to-face consultations. DESIGN AND SETTING: Cross-sectional comparison of data from NHS Choices and telephone survey data reported by general practice staff, for a nationally representative sample of 320 general practices (December 2013 to September 2014). METHOD: GP face-to-face consultation times were collected by telephone for each sampled practice for each day of the week. NHS Choices data on surgery times were available online. Analysis was based on differences in the number of surgery hours (accounting for breaks) and the times of the first and last consultations of the day only between the two data sources. RESULTS: The NHS Choices data recorded 8.8 more hours per week than the survey data on average (40.1 versus 31.2; 95% confidence interval [CI] = 7.4 to 10.3). This was largely accounted for by differences in the recording of breaks between sessions. The data were more similar when only the first and last consultation times were considered (mean difference = 1.6 hours; 95% CI = 0.9 to 2.3). CONCLUSION: NHS Choices data do not accurately measure the number of hours in which GPs provide face-to-face consultations. They better record the hours between the first and last consultations of the day.

Primary care access and its relationship with emergency department utilisation: an observational, cross-sectional, ecological study.

BACKGROUND: Recent health service policies in the UK have focused on improving primary care access in order to reduce the use of costly emergency department services, even though the relationship between the two is based on weak or little evidence. Research is required to establish whether improving primary care access can influence emergency department attendance. AIM: To ascertain whether a relationship exists between the degree of access to GP practices and avoidable emergency department attendances in an inner-London primary care trust (PCT). DESIGN AND SETTING: Observational, cross-sectional ecological study in 68 general practices in Brent Primary Care Trust, north London, UK. METHOD: GP practices were used as the unit of analysis and avoidable emergency department attendance as the dependent variable. Routinely collected data from GP practices, Hospital Episode Statistics, and census data for the period covering 2007-2009 were used across three broad domains: GP access characteristics, population characteristics, and health status aggregated to the level of the GP practice. Multiple linear regression was used to ascertain which variables account for the variation in emergency department attendance experienced by patients registered to each GP practice. RESULTS: None of the GP access variables accounted for the variation in emergency department attendance. The only variable that explained this variance was the Index of Multiple Deprivation (IMD). For every unit increase in IMD score of the GP practice, there would be an increase of 6.13 (95% CI = 4.56, 7.70) per 1000 patients per year in emergency department attendances. This accounted for 47.9% of the variance in emergency department attendances in Brent. CONCLUSION: Avoidable emergency department attendance appears to be mostly driven by underlying deprivation rather than by the degree of access to primary care.

Effects of hydrogen peroxide and apolipoprotein E isoforms on apolipoprotein E trafficking in HepG2 cells.

1. The major source of apolipoprotein E (apoE) is the liver. In the present study, the effects of oxidative stress and apoE isoforms on apoE distribution and trafficking were established using the HepG2 liver tumour cell line. 2. Hydrogen peroxide (0, 25, 250 and 1000 micromol/L) was associated with rapid and concentration-dependent redistribution of apoE into the early endosomal compartment. This redistribution was achieved with a much lower concentration (25 micromol/L) than that needed to induce changes in intracellular apoE mRNA expression, apoE protein levels and markers of oxidative stress (250-1000 micromol/L). 3. Live cell imaging of apoE3-green fluorescent protein revealed a significant decrease in traffic velocity in response to oxidative stress. 4. The E4 isoform was associated with reduced trafficking velocity compared with the E3 isoform under basal conditions. 5. The results indicate that oxidative stress and apoE isoforms influence apoE trafficking and distribution within HepG2 cells. Altered apoE hepatocyte trafficking may provide a mechanistic link between oxidative stress, ageing and some diseases in older people.