Ethical preparedness in health research and care: the role of behavioural approaches

Background

Public health scholars have long called for preparedness to help better negotiate ethical issues that emerge during public health emergencies. In this paper we argue that the concept of ethical preparedness has much to offer other areas of health beyond pandemic emergencies, particularly in areas where rapid technological developments have the potential to transform aspects of health research and care, as well as the relationship between them. We do this by viewing the ethical decision-making process as a behaviour, and conceptualising ethical preparedness as providing a health research/care setting that can facilitate the promotion of this behaviour. We draw on an implementation science and behaviour change model, COM-B, to demonstrate that to be ethically prepared requires having the capability (ability), opportunity, and motivation (willingness) to work in an ethically prepared way.

Methods

We use two case examples from our empirical research—one pandemic and one non-pandemic related—to illustrate how our conceptualisation of ethical preparedness can be applied in practice. The first case study was of the UK NHSX COVID-19 contact tracing application case study involved eight in-depth interviews with people involved with the development/governance of this application. The second case involved a complex case regarding familial communication discussed at the UK Genethics Forum. We used deductive qualitative analysis based on the COM-B model categories to analyse the transcripbed data from each case study.

Results

Our analysis highlighted that being ethically prepared needs to go beyond merely equipping health professionals with skills and knowledge, or providing research governance actors with ethical principles and/or frameworks. To allow or support these different actors to utilise their skills and knowledge (or principles and frameworks), a focus on the physical and social opportunity is important, as is a better understanding the role of motivation.

Conclusions

To understand ethical preparedness, we need to view the process of ethical decision-making as a behaviour. We have provided insight into the specific factors that are needed to promote this behaviour—using examples from both in the pandemic context as well as in areas of health research and medicine where there have been rapid technological developments. This offers a useful starting point for further conceptual work around the notion of being ethically prepared.

Co-locating public mental health services in communities: a realist evaluation

Background

Public mental health (PMH) services address social determinants of mental health, such as poverty, poor housing, and job insecurity. Austerity and welfare reform in the UK has led to cuts to social and welfare support, increasing poor mental health and widening inequalities, exacerbated by COVID-19. State health services lack capacity to tackle social issues that contribute to a large proportion of expressed mental health need. Co-locating PMH services within community spaces is a potential solution to increase early access and improve quality of services. Using a realist evaluation, we sought to develop the theory on how community co-location affects PMH outcomes, who this works best for, and how this is impacted by the context of delivery.

Methods

We collected data from service-users and service-providers at six case study sites across England, UK, using interviews (n = 62), four focus groups (n = 40) and two stakeholder workshops (n = 19).

Results

We identified four overarching theories. First, community providers do not operate under the same limits as state services allowing them the flexibility and time to build trust and ongoing relationships with service users. Second, the ethos and culture of services is to empower users to access help and be independent. Third, accessing support from a shared local space allows a coordinated and holistic response reducing barriers such as distance, cost, and anxiety. Four, as they are recreational services and spaces for access by all with no predefined/required level of need they are better at promoting wellbeing and primary prevention.

Conclusions

Community co-location of PMH services can strengthen the overall mental health system by widening reach to people vulnerable to poor mental health and enabling earlier intervention on associated social determinants. This has potential to reduce mental health inequalities and demand on the state health system.

Key messages

Exploring how biobanks communicate the possibility of commercial access and its associated benefits and risks in participant documents

Background

Biobanks and biomedical research data repositories collect their samples and associated data from volunteer participants. Their aims are to facilitate biomedical research and improve health, and they are framed in terms of contributing to the public good. Biobank resources may be accessible to researchers with commercial motivations, for example, researchers in pharmaceutical companies who may utilise the data to develop new clinical therapeutics and pharmaceutical drugs. Studies exploring citizen perceptions of public/private interactions associated with large health data repositories/biobanks indicate that there are sensitivities around public/private and/or non-profit/profit relationships and international sample and data sharing. Less work has explored how biobanks communicate their public/private partnerships to the public or to their potential research participants.

Methods

We explored how a biobank’s aims, benefits and risks, and private/public relationships have been framed in public facing recruitment documents (consent forms and participant information sheets).

Results

Biobank documents often communicate their commercial access arrangements but not the detail about what these interactions would entail, and how risks and benefits would be distributed to the public.

Conclusion

We argue that this leads to a polarised discourse between public and private entities and/or activities, and fails to attend to the blurred lines between them. This results in a lack of attention to more important issues such as how risks and benefits in general are distributed to the public. We call for a nuanced approach that can contribute to the much-needed dialogue in this space.

Ethical Reasoning During a Pandemic: Results of a Five Country European Study

Introduction: There has been no work that identifies the hidden or implicit normative assumptions on which participants base their views during the COVID-19 pandemic, and their reasoning and how they reach moral or ethical judgements. Our analysis focused on participants' moral values, ethical reasoning and normative positions around the transmission of SARS-CoV-2.Methods: We analyzed data from 177 semi-structured interviews across five European countries (Germany, Ireland, Italy, Switzerland and the United Kingdom) conducted in April 2020.Results: Findings are structured in four themes: ethical contention in the context of normative uncertainty; patterns of ethical deliberation when contemplating restrictions and measures to reduce viral transmission; moral judgements regarding "good" and "bad" people; using existing structures of meaning for moral reasoning and ethical judgement.Discussion: Moral tools are an integral part of people's reaction to and experience of a pandemic. 'Moral preparedness' for the next phases of this pandemic and for future pandemics will require an understanding of the moral values and normative concepts citizens use in their own decision-making. Three important elements of this preparedness are: conceptual clarity over what responsibility or respect mean in practice; better understanding of collective mindsets and how to encourage them; and a situated, rather than universalist, approach to the development of normative standards.

Sustainable biobanks: a case study for a green global bioethics

This paper argues that as we move to redefine global bioethics, there is a need to be attentive to the ethical issues associated with the environmental sustainability of data and digital infrastructures in global health systems. We show that these infrastructures have thus far featured little in environmental impact discussions in the context of health, and we use a case study approach of biobanking to illustrate this. We argue that this missing discussion is problematic because biobanks have environmental impacts associated with data and digital infrastructures. We consider several ethical questions to consider these impacts: what ethical work does the concept of environmental sustainability add to the debate; how should this concept be prioritised in decision-making; and who should be responsible for doing so? We call on global bioethics to play a role in advancing this dialogue and addressing these questions.

Framing ethical issues associated with the UK COVID-19 contact tracing app: exceptionalising and narrowing the public ethics debate

This paper explores ethical debates associated with the UK COVID-19 contact tracing app that occurred in the public news media and broader public policy, and in doing so, takes ethics debate as an object for sociological study. The research question was: how did UK national newspaper news articles and grey literature frame the ethical issues about the app, and how did stakeholders associated with the development and/or governance of the app reflect on this? We examined the predominance of different ethical issues in news articles and grey literature, and triangulated this using stakeholder interview data. Findings illustrate how news articles exceptionalised ethical debate around the app compared to the way they portrayed ethical issues relating to 'manual' contact tracing. They also narrowed the debate around specific privacy concerns. This was reflected in the grey literature, and interviewees perceived this to have emerged from a 'privacy lobby'. We discuss the findings, and argue that this limited public ethics narrative masked broader ethical issues.

Community interventions for improving adult mental health: mapping local policy and practice in England

BACKGROUND

Public mental health (PMH) aims to improve wellbeing and prevent poor mental health at the population level. It is a global challenge and a UK priority area for action. Communities play an important role in the provision of PMH interventions. However, the evidence base concerning community-based PMH interventions is limited, meaning it is challenging to compare service provision to need. Without this, the efficient and equitable provision of services is hindered. Here, we sought to map the current range of community-based interventions for improving mental health and wellbeing currently provided in England to inform priority areas for policy and service intervention.

METHOD

We adopted an established mapping exercise methodology, comparing service provision with demographic and deprivation statistics. Five local authority areas of England were selected based on differing demographics, mental health needs and wider challenging circumstances (i.e. high deprivation). Community-based interventions were identified through: 1) desk-based research 2) established professional networks 3) chain-referral sampling of individuals involved in local mental health promotion and prevention and 4) peer researchers' insight. We included all community-based, non-clinical interventions aimed at adult residents operating between July 2019 and May 2020.

RESULTS

407 interventions were identified across the five areas addressing 16 risk/protective factors for PMH. Interventions for social isolation and loneliness were most prevalent, most commonly through social activities and/or befriending services. The most common subpopulations targeted were older adults and people from minority ethnic backgrounds. Interventions focusing on broader structural and environmental determinants were uncommon. There was some evidence of service provision being tailored to local need, though this was inconsistent, meaning some at-risk groups such as men or LGBTQ+ people from minority ethnic backgrounds were missed. Interventions were not consistently evaluated.

CONCLUSIONS

There was evidence of partial responsiveness to national and local prioritising. Provision was geared mainly towards addressing social and individual determinants of PMH, suggesting more integration is needed to engage wider service providers and policy-makers in PMH strategy and delivery at the community level. The lack of comprehensive evaluation of services to improve PMH needs to be urgently addressed to determine the extent of their effectiveness in communities they serve.

COVID-19 contact tracing apps: UK public perceptions

In order to combat the COVID-19 pandemic, policymakers around the globe have increasingly invested in digital health technologies to support the ‘test, track and trace’ approach of containing the spread of the novel coronavirus. These technologies include mobile ‘contact tracing’ applications (apps), which can trace individuals likely to have come into contact with those who have reported symptoms or tested positive for the virus and request that they self-isolate. This paper takes a critical public health perspective that advocates for ‘genuine participation’ in public health interventions and emphasises the need to take citizen’s knowledge into account during public health decision-making. In doing so, it presents and discusses the findings of a UK interview study that explored public views on the possibility of using a COVID-19 contact-tracing app public health intervention at the time the United Kingdom (UK) Government announced their decision to develop such a technology. Findings illustrated interviewees’ range and degree of understandings, misconceptions, and concerns about the possibility of using an app. In particular, concerns about privacy and surveillance predominated. Interviewees associated these concerns much more broadly than health by identifying with pre-existent British national narratives associated with individual liberty and autonomy. In extending and contributing to ongoing sociological research with public health, we argue that understanding and responding to these matters is vital, and that our findings demonstrate the need for a forward-looking, anticipatory strategy for public engagement as part of the responsible innovation of the COVID-19 contact-tracing app in the UK.

Unbalanced Flows in the Subtle Body: Tibetan Understandings of Psychiatric Illness and How to Deal With It

Much of what Western medicine classifies as psychiatric illness is understood by Tibetan thought as associated with imbalance of rlung (wind, breath). Rlung has a dual origin in Indian thought, combining elements from Ayurvedic medicine and Tantric Buddhism. Tibetan theories of rlung seem to correspond in significant ways with Western concepts of the autonomic nervous system (ANS), and Western medicine too has associated psychiatric issues with ANS problems. But what is involved in relating Tibetan ideas of rlung to Western ideas of the emotions and the ANS? The article presents elements of the two systems and then explores similarities and differences between them. It asks whether the similarities could be the basis for a productive encounter between Tibetan and Western modes of understanding and treating psychiatric illness. What could Western psychiatry learn from Tibetan approaches in this area?

Is It Time to Re-Evaluate the Ethics Governance of Social Media Research?

This article reports on a U.K. workshop on social media research ethics held in May 2018. There were 10 expert speakers and an audience of researchers, research ethics committee members, and research institution representatives. Participants reviewed the current state of social media ethics, discussing well-rehearsed questions such as what needs consent in social media research, and how the public/private divide differs between virtual and real-life environments. The lack of answers to such questions was noted, along with the difficulties posed for ethical governance structures in general and the work of research ethics committees in particular. Discussions of these issues enabled the creation of two recommendations. The first is for research ethics committees and journal editors to add the category of ‘data subject research’ to the existing categories of ‘text research’ and ‘human subject research’. This would reflect the fact that social media research does not fall into either of the existing categories and so needs a category of its own. The second is that ethical issues should be considered at all stages of social media research, up to and including aftercare. This acknowledges that social media research throws up a large number of ethical issues throughout the process which, under current arrangements for ethical research governance, risks remaining unaddressed.

From "a Fair Game" to "a Form of Covert Research": Research Ethics Committee Members' Differing Notions of Consent and Potential Risk to Participants Within Social Media Research

Social media (SM) research presents new challenges for research ethics committees (RECs) who must balance familiar ethical principles with new notions of public availability. This article qualitatively examines how U.K. REC members view this balance in terms of risk and consent. While it found significant variance overall, there were discernible experience-based trends. REC members with less experience of reviewing SM held inflexible notions of consent and risk that could be categorized as either relying on traditional notions of requiring direct consent, or viewing publicly available data as “fair game.” More experienced REC members took a more nuanced approach to data use and consent. We conclude that the more nuanced approach should be best practice during ethical review of SM research.

Doxorubicin enhances (131)I-rituximab induced cell death in Raji cells

AIM

There are various therapeutic modalities of treatment for non-Hodgkin's lymphoma, but with certain limitations, hence, investigating the scope of combined therapeutic approach.

MATERIALS AND METHODS

In this article, cellular toxicity, apoptosis and expression of mitogen-activated protein kinase signaling pathway proteins were investigated in Raji cells preincubated with doxorubicin followed by (131)I-rituximab (rituximab radiolabeled with Iodine-131) treatment.

RESULTS

It was found that the (131)I-rituximab in combination with doxorubicin showed a higher amount of cell toxicity and apoptosis compared to respective controls. Expression of anti-apoptotic protein (B-cell lymphoma-extra-large) was downregulated and cleavage of poly (ADP-ribose) polymerase, a marker of apoptosis was higher in cells treated with doxorubicin (2 μg/mL) and 131 I-rituximab (P ≤ 0.05). Moreover, in these cells the basal level of expression of p42/44 and p38 were increased while its phosphorylation was decreased.

CONCLUSION

These results suggest that doxorubicin has the potential to sensitize (131)I-rituximab induced cell death in Raji cells.

The contemporary mindfulness movement and the question of nonself1

Mindfulness-based stress reduction (MBSR), mindfulness-based cognitive therapy (MBCT), and other "mindfulness"-based techniques have rapidly gained a significant presence within contemporary society. Clearly these techniques, which derive or are claimed to derive from Buddhist meditational practices, meet genuine human needs. However, questions are increasingly raised regarding what these techniques meant in their original context(s), how they have been transformed in relation to their new Western and global field of activity, what might have been lost (or gained) on the way, and how the entire contemporary mindfulness phenomenon might be understood. The article points out that first-generation mindfulness practices, such as MBSR and MBCT, derive from modernist versions of Buddhism, and omit or minimize key aspects of the Buddhist tradition, including the central Buddhist philosophical emphasis on the deconstruction of the self. Nonself (or no self) fits poorly into the contemporary therapeutic context, but is at the core of the Buddhist enterprise from which contemporary "mindfulness" has been abstracted. Instead of focussing narrowly on the practical efficacy of the first generation of mindfulness techniques, we might see them as an invitation to explore the much wider range of practices available in the traditions from which they originate. Rather, too, than simplifying and reducing these practices to fit current Western conceptions of knowledge, we might seek to incorporate more of their philosophical basis into our Western adaptations. This might lead to a genuine and productive expansion of both scientific knowledge and therapeutic possibilities.

Comparative biological evaluation of two [99mTc(CO)3]-dextran pyrazolyl mannose conjugates developed for use in sentinel lymph node detection

AIM

This work aims to develop receptor based alternatives to the conventional colloidal tracers in sentinel lymph node (SLN) detection. In this study, we report the detailed biological evaluation of two dextran pyrazolyl mannose derivatives towards this purpose.

METHODS

The dextran pyrazolyl mannose derivatives (DAPM4 and DAPM8) were labeled with the [99mTc(CO)3(H2O)3]+ core. In vitro saturation binding studies for the ligands were performed in mannose receptor-bearing RAW 264.7 macrophage precursor cells. Localization and pharmacokinetics studies of the tracers were conducted in normal Wistar rats with different ligand concentrations using in vivo activity distribution and scintigraphic imaging techniques.

RESULTS

The ligands were labeled with the [99mTc(CO)3)]+ core in high yield and radiochemical purity (>90%). DAPM4 and DAPM8 showed specific uptake in RAW 264.7 cells. In vivo localization studies showed concentration-dependent uptake and selective retention of the [99mTc]-labeled complexes of DAPM4 and DAPM8 in the sentinel node with highly favorable values of popliteal extraction [PE] (%PEDAPM4=92.94%,%PEDAPM8=91.80% at 180 min p.i.) and rapid clearance from the site of injection when administered at 50 µg/mL ligand concentration.

CONCLUSION

[99mTc(CO)3]-complexes of DAPM4 and DAPM8 show good in vivo potential to undergo further testing as agents for SLN detection in the clinic and their biological efficacy varies depending upon the concentration of ligands used for the procedure.

DESIGN OF IMMUNORADIOMETRIC ASSAY FOR GONADOTROPINS USING A COMMON DETECTION ANTIBODY: AN EXPERIENCE

We share our experience in the development of immunoradiometric assay (IRMA) for gonadotropins, FSH and LH using common tracer concept. Commercially procured, monoclonal antibody against 'common epitope' of FSH and LH was radiolabeled and epitope specific monoclonal antibody against β-subunit of FSH and LH was chemically immobilized and used as a capture system. In an inclusive assay procedure developed, 100 µl of respective standard and specific capture antibody was incubated with 100 µl common tracer, for 3 h at RT with shaking. Results of validation tests confirmed the clinical utility of the developed procedure with adequate sensitivity of 1.0 mIU/ml, acceptable precision (imprecision CV ≤ 10%), minimal cross-reaction.

Complexation studies with 90Y from a novel 90Sr-90Y generator

Some features of a novel 90Sr-90Y generator which employs supported liquid membrane (SLM) to separate carrier-free 90Y from 90Sr present in the high level waste of the spent fuel of reactor are described. After ascertaining the purity of 90Y particularly with respect to 90Sr breakthrough, its complexation was studied with a few oxo/aza donor ligands, such as DTPA, EDTMP, DOTA, TETA and a cyclic phosphonate, CTMP. These studies were primarily carried out to adjudge the quality of the 90Y obtained from a novel 90Sr-90Y generator and ascertain its usability for labelling biomolecules such as antibodies and peptides. The DOTA complexes are most stable at 37 C in human serum; they appear to be ideal bifunctional chelating agent for use in radioimmunotherapy with 90Y.

Surface Modification of Polystyrene Using Polyaniline Nanostructures for Biomolecule Adhesion in Radioimmunoassays

The selection of an appropriate surface as a solid phase for coupling antibodies is a critical step in the development of solid-phase immunoassays. Availability of a new method of preactivating the surface of polystyrene tubes with a layer of another polymer for enhanced immobilization of antibodies seems to be promising. In this paper, we report the activation of a polystyrene surface using a layer of polyaniline and its effect on immobilizing antibodies for use as a solid phase in a T3 immunoassay. The modified surface on the polystyrene was characterized by optical absorption, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The modified tubes were coated with antibody and evaluated for their performance in the assay and validated for radioimmunoassay of T3. AFM images of the modified surface showed an enhancement in the surface roughness (Ra of 20.2 nm), as compared to an unmodified surface (Ra of 6 nm), allowing more adsorption of antibodies to the surface. XPS revealed the presence of N (binding energy approximately 400 eV) on the modified surface, which could help the antibody molecules to bind to these preactivated (modified) tubes. The modified tubes, when coated with antibody, not only showed an increase in the binding with the radioiodinated tracer but also improved the precision of coating the antibody. The present method of activating polystyrene surfaces is simple, does not involve severe chemical treatment, and may have wide applicability to functionalize other supports for immobilizing biomolecules.

Development of coated tubes RIA for serum T3 (tri-iodothyronine) for production scale

A coating procedure that could provide immobilization of antibodies, with increased binding capacity, that is cost effective, simple, robust, and appropriate for production scale application, is described. This coating approach of T3 antibodies to the polystyrene tubes has been systematically investigated to determine its utility for the development of coated tube Radioimmunoassay (RIA) for T3 in human serum. Further, the results obtained by the developed coating procedure are found to be comparable with those obtained by the "gold standard," the liquid phase RIA for T3. The coating procedure is completed in three major steps, each step involving an overnight incubation. The normal rabbit gamma-globulins are physically adsorbed onto the polystyrene tubes and incubated. After washing, a second antibody (goat anti-rabbit antiserum) is added and incubated. To this antigen specific antibody is added (T3 antibody produced in rabbit) and further incubated. Finally, the non-specific sites on the tubes are saturated by the blocking solution. The concentration of normal rabbit globulin, titers of second antibody and T3 antibody, and time required for coating are optimized to arrive at a suitable coating protocol. The coated tubes were evaluated for precision, reproducibility, and stability. Various parameters such as total reaction volume, incubation time and temperature, total number and volume of washings, concentration of 8-anilino-1-naphthalene sulfonic acid (ANS), and quantity of tracer per tube are optimized to arrive at a suitable standard curve. The optimized assay is validated for the quality control parameters such as intra- and inter-assay variations, recovery, and parallelism. The developed coated tubes assay had an assay range of 0.3-4.8 ng/mL with a sensitivity of 0.3 ng/mL at 90% B/B0. Batch to batch variation in coating was < 10%. The coated tubes were stable up to 1 year, which is adequate for production scale.

177Lu labelled polyaminophosphonates as potential agents for bone pain palliation

Polyphosphonate ligands labelled with radioisotopes decaying by moderate energy beta emission have shown utility as palliative agents for painful bone metastasis. 177Lu (T(1/2)=6.71 d, Ebetamax=497 keV) has radionuclidic properties suitable for use in palliative therapy of bone metastasis. 177Lu was produced at a high specific activity and excellent radionuclidic purity by thermal neutron bombardment of a target prepared from natural Lu. Three polyaminomethylene phosphonate ligands, abbreviated as EDTMP, DTPMP and TTHMP, were synthesized and radiolabelled with 177Lu. Complexation parameters were optimized to achieve maximum yields (97-99.5%). All the complexes were found to retain their stability at room temperature even 14 days after preparation. Biodistribution studies of the complexes were carried out in Wistar rats. All the complexes showed significant bone uptake (6-6.5%/g in tibia at 3 h post-injection (p.i.)) with rapid clearance from blood and minimum uptake in soft tissues. These studies reveal that 177Lu complexes with the synthesized ligands have a potential use in palliative treatment of painful bone metastasis.

A novel [186/188Re]-labelled porphyrin for targeted radiotherapy

The concept of labelling a porphyrin, a tumour-avid agent, with a radionuclide to evaluate its potential as a therapeutic modality is reported. A novel water-soluble porphyrin, namely meso-tetrakis[3,4-bis(carboxymethyleneoxy)phenyl]porphyrin, with suitable dicarboxylic acid groups as aromatic substituents in the periphery, was synthesized and characterized. The labelling of this porphyrin with 186/188Re, a beta(-) emitter, was optimized by varying the reaction conditions. The complexation yield was >98% as estimated by paper chromatography in acetone and in saline. The radiochemical purity was found to remain at >98% when stored at 4 degrees C for 24 h. Biodistribution studies in Swiss mice bearing fibrosarcomas showed an uptake of approximately 3.5% per gram of tumour at 30 min post-injection. This uptake in the tumour was retained until 24 h post-injection with major activity showing renal clearance; no significant activity was present in other organs of interest. The tumour/blood and tumour/muscle ratios were observed to be 38 and 5, respectively, at 24 h post-injection, thereby indicating a possible therapeutic potential for tumours.

186Re-1,4,8,11-tetraaza cyclotetradecyl-1,4,8,11-tetramethylene phosphonic acid: a novel agent for possible use in metastatic bone-pain palliation

In connection with our work on the development of 186Re-tetra-phosphonates with optimum properties for use in bone pain palliation, a novel cyclic tetraphosphonate derivative, has been synthesized, complexed with 186Re and evaluated with promising results. The ligand, which consists of a cyclic array of tetra-aminomethylphosphonate groups, was synthesized using orthophosphorus acid, 1,4,8,11-tetraazacyclotetradecane and formaldehyde. The labeling conditions with 186Re have been standardized under varying reaction conditions to give maximum yield. In a reaction volume of 1 mL, maximum complexation yield of 98% was observed at pH 2 using 0.1 mg Re (37-370 MBq) for a ligand concentration at 9 x 10(-2) M/L, under heating at 100 degrees C for 30 min with 2 mg of stannous chloride. The complex was found to be stable for 6 days with RC purity remaining approximately 97%. The complex was characterized by paper chromatography in saline and acetone, wherein the R(f) exhibited were 0.9 and 0, respectively. Biodistribution studies of the complex were performed in male Wistar rats. Activity in femur which was observed to be 1.8%/g (equivalent to about 23% of the injected activity in skeleton) at 3 h post injection remained almost constant up to 48 h. Minimum activity was observed in blood and other soft tissues. The complex showed major renal clearance. Scintigraphic images in rabbits after injecting 70-100 MBq of 186Re-CTMP and using a dual head gamma camera were observed to be superior to 186Re-HEDP, prepared by a procedure standardized by us. Insignificant activity was observed in other vital organs. The results suggest the suitability of the complex for further evaluation in higher animals for bone pain palliation.

Conservation of a DPP/BMP signaling pathway in the nonbilateral cnidarian Acropora millepora

Members of the TGF-beta superfamily of signaling molecules are widespread in metazoans, but the evolutionary origin of particular subclasses of signaling mechanisms is poorly defined. The DPP/BMP class, for example, is implicated in dorsal-ventral patterning, neural patterning, and limb development. Here we report the presence of several components of a DPP/BMP-specific signal transduction cascade in a nonbilateral animal, the coral Acropora millepora. The discovery of these components, a putative type I receptor and two putative receptor-activated Smads, suggests that DPP/BMP signaling predates both dorsal-ventral pattern formation and limb development. We postulate that an ancestral role in neuroepithelial patterning may account for the high level of conservation between DPP/BMP signaling components found in this nonbilateral animal and the more complex triploblastic organisms of the arthropod and chordate phyla.

Potential (166)Ho radiopharmaceuticals for intravascular radiation therapy (IVRT)-I: [(166)Ho] holmium labeled ethylene dicysteine

The use of beta(-) emitting radionuclides in the control of restenosis in post angioplasty patients is currently under intense investigation at many leading cardiovascular research centers. (32)P coated metallic stents, (192)Ir wire source and balloons filled with an appropriate radionuclide solution such as of (188)Re, attached to catheter are being studied. (166)Ho has comparable radionuclidic properties to that of (188)Re, can be more easily produced and hence is an attractive alternative to (188)Re. Ethylene dicysteine complex of (166)Ho was prepared and its pharmacological behavior studied. Optimum conditions for the preparation of complex with respect to the reaction time, ligand concentration, pH of the reaction mixture as well as reaction temperature were standardized. The stability of the labeled complex at room temperature as well as at 4 degrees C was determined. Biodistribution pattern of the injected complex in Wistar rats was estimated at 10 min, 30 min and 3 h post injection. This study indicated that >90% of the injected (166)Ho-EC complex was excreted in urine within 3 h post injection, with insignificant retention in any major organ. These studies reveal that (166)Ho-EC could be a viable substitute for (188)Re compounds in radioactive liquid-filled balloon IVRT.

Tc-99m and Re-186 complexes of tetraphosphonate ligands and their biodistribution pattern in animal models

The syntheses of four alpha-aminomethyl phosphonates and their complexation studies with (99m)Tc and (186/188)Re are reported. Complexation conditions were standardized to give maximum yields, which ranged from 90-97%. The yields of complexation were estimated by paper chromatography. The (99m)Tc complexes were stable for more than 4 h, while the (186/188)Re complexes were stable for 3-8 days when stored at 4 degrees C. Biodistribution of these complexes in Wistar rats were carried out, and the uptake in bone and other soft tissue are detailed. Bone uptake of the (99m)Tc complexes varied from 40-60% at 30 min postinjection depending on the ligands. The uptake in soft tissue was minimum with all the complexes. A comparison of the biodistribution studies of the (99m)Tc complexes with that of the well-established radiopharmaceutical (99m)Tc-MDP was carried out for the purpose of evaluating the efficacy of the radiopharmaceutical preparation with the complexes of these ligands. The bone uptake of the (186/188)Re complexes varied from 19-28% corresponding to 1.6-3% per g at 3 h postinjection. The residual activity in both (99m)Tc and (186/188)Re complexes showed renal clearance.

Studies on the preparation and stability of samarium-153 propylene diamine tetramethylene phosphonate (PDTMP) complex as a bone seeker

Propylene diamine tetra methylene phosphonate (PDTMP) was synthesised by modifying a method reported for the synthesis of EDTMP. Complexation of the synthesised phosphonate ligand with 153Sm was carried out by varying the experimental parameters and the complex was radiochemically characterized. Biodistribution studies showed that the uptake by bone in rats was 2% per g of bone, which was retained upto 48 h. The uptake by other organs was insignificant, except by the liver which showed a slightly higher absorption.

188Re-ethylene dicysteine: a novel agent for possible use in endovascular radiation therapy

Several agents, such as 188ReO4-, 188Re-MAG3 and 188Re-DTPA are currently under investigation as radiation sources in liquid-filled balloons for prevention of restenosis following coronary angioplasty. Bearing in mind the risk factor associated with leakage of radioactivity in the event of balloon rupture, the criteria sought in selecting suitable agents for endovascular radiation therapy (EVRT) are rapid clearance and low dose to vital organs. Since 99Tcm labelled ethylene dicysteine (EC) is a well established agent for renal tubular function imaging, the use of 186Re-ethylene dicysteine as a potential agent for prevention of restenosis after angioplasty has been evaluated previously. Therefore, it was of interest to evaluate the applicability of the more potential isotope of rhenium, 188Re, a high energy beta-emitter (Ebetamax = 2.12 MeV) with a suitable T 1/2 = 16.9 h, obtainable carrier-free from the 188W-188Re generator, as an attractive and alternative radionuclide for labelling with L,L-EC. In this paper, the preparation and pharmacological behaviour of the 188Re complex of ethylene dicysteine are reported. The complex can be prepared in high yields (99.5%) under optimized conditions of pH 2-3, at a ligand concentration of 15 mM, 50 microg (0.18 mM) carrier rhenium and using 2 mg x mL(-1) stannous chloride. On storage at 4 degrees C, the RC purity was more than 97% after 48 h when prepared under optimum conditions. Biodistribution studies in Wistar rats showed the desired characteristics of fast blood clearance and low retention of activity in the vital organs (< 2% in intestine, < 1% in stomach, < 0.5% in liver) with a high renal excretion (90.65+/-0.6%) at 3 h post-injection. These results confirm the advantages of using the 188Re-EC complex compared with perrhenate and other rhenium radiopharmaceuticals currently being used in balloons for EVRT.

[(186/188)Re] rhenium-ethylene dicysteine (Re-Ec): preparation and evaluation for possible use in endovascular brachytherapy

188ReO(4)(-), (188)Re-MAG(3), and (188)Re-DTPA are currently under investigation as radiation sources in liquid-filled balloons for prevention of restenosis following coronary angioplasty. Because (99m)Tc-labeled ethylene dicysteine (EC) is a well-established agent for renal tubular function imaging, the use of [(188)Re] rhenium-labeled EC as a potential agent for prevention of restenosis after angioplasty is worth evaluation. In this article, the preparation and pharmacological behavior of [(188/186)Re]Re complex of EC are reported. The yield of the Re complex was optimized by varying the parameters of complexation. The complex prepared under the optimized conditions was found to be stable over a period of 7 days when stored at pH 2 and at 4 degrees C. The pharmacological behavior of [(188/186)Re]Re-EC confirms its similarity to (188)Re-MAG(3) and its superiority over (188)ReO(4)(-) for use in endovascular brachytherapy.

Radiochemical studies of 99mTc complexes of modified cysteine ligands and bifunctional chelating agents

The synthesis of four novel ligands using the amino-acid cysteine and its ethyl carboxylate derivative is described. The synthetic method involves a two-step procedure, wherein the intermediate Schiff base formed by the condensation of the amino group of the cysteine substrate and salicylaldehyde is reduced to give the target ligands. The intermediates and the final products were characterized by high resolution nuclear magnetic resonance spectroscopy. Complexation studies of the ligands with 99mTc were optimized using stannous tartrate as the reducing agent under varying reaction conditions. The complexes were characterized using standard quality control techniques such as thin layer chromatography, paper electrophoresis, and paper chromatography. Lipophilicities of the complexes were estimated by solvent extraction into chloroform. Substantial changes in net charge and lipophilicity of the 99mTc complexes were observed on substituting the carboxylic acid functionality in ligands I and II with the ethyl carboxylate groups (ligands II and IV). All the ligands formed 99mTc complexes in high yield. Whereas the complexes with ligands I and II were observed to be hydrophilic in nature and not extractable into CHCl3, ligands III and IV resulted in neutral and lipophilic 99mTc complexes. The 99mTc complex with ligand II was not stable and on storage formed a hydrophilic and nonextractable species. The biodistribution of the complexes of ligands I and II showed that they cleared predominantly through the kidneys, whereas the complexes with ligands III and IV were excreted primarily through the hepatobiliary system. No significant brain uptake was observed with the 99mTc complexes with ligands III and IV despite their favorable properties of neutrality, lipophilicity, and conversion into a hydrophilic species. These ligands offer potential for use as bifunctional chelating agents.

Technetium-99m complexes of polydentate amine-pyrrole and amine-thiophene ligands

Novel polydentate amine-pyrrole and amine-thiophene ligands were synthesized and characterized by 1H and 13C NMR spectroscopy. Radiochemical studies with 99mTc were carried out at 0.1-100 microM of technetium. Complexation yields were estimated from thin layer chromatography (TLC), paper electrophoresis, and solvent extraction studies. The 99mTc complexes formed were found to be neutral and lipophilic. Complexes with the corresponding imine-ligands were formed in lower yields. Biodistribution studies of the 99mTc complexes of these ligands showed no significant uptake in brain or heart, and the clearance was mainly through the hepatobiliary system.