Navigating Transcriptional Coregulator Ensembles to Establish Genetic Networks: A GATA Factor Perspective.

Complex developmental programs require orchestration of intrinsic and extrinsic signals to control cell proliferation, differentiation, and survival. Master regulatory transcription factors are vital components of the machinery that transduce these stimuli into cellular responses. This is exemplified by the GATA family of transcription factors that establish cell type-specific genetic networks and control the development and homeostasis of systems including blood, vascular, adipose, and cardiac. Dysregulated GATA factor activity/expression underlies anemia, immunodeficiency, myelodysplastic syndrome, and leukemia. Parameters governing the capacity of a GATA factor expressed in multiple cell types to generate cell type-specific transcriptomes include selective coregulator usage and target gene-specific chromatin states. As knowledge of GATA-1 mechanisms in erythroid cells constitutes a solid foundation, we will focus predominantly on GATA-1, while highlighting principles that can be extrapolated to other master regulators. GATA-1 interacts with ubiquitous and lineage-restricted transcription factors, chromatin modifying/remodeling enzymes, and other coregulators to activate or repress transcription and to maintain preexisting transcriptional states. Major unresolved issues include: how does a GATA factor selectively utilize diverse coregulators; do distinct epigenetic landscapes and nuclear microenvironments of target genes dictate coregulator requirements; and do gene cohorts controlled by a common coregulator ensemble function in common pathways. This review will consider these issues in the context of GATA factor-regulated hematopoiesis and from a broader perspective.

The chemokine CXCL12 and its receptor CXCR4 are implicated in human seminoma metastasis.

Seminoma and non-seminoma tumours increasingly occur within the western population. These tumours originate from carcinoma in situ (CIS) cells, which arise from dysfunctional gonocytes. CXCL12 and its receptors, CXCR4 and CXCR7, have been implicated in migration, proliferation and survival of gonocytes and their precursors and progeny, primordial germ cells and spermatogonial stem cells respectively. We previously found evidence that several miRNA molecules predicted to modulate CXCR4 signalling are differentially expressed during the differentiation of gonocytes into spermatogonia in mice. Bioinformatic analysis predicted these miRNA to modulate CXCR4 signalling, leading us to hypothesize that CXCL12-mediated CXCR4 signalling is involved in the disrupted differentiation of gonocytes that underpins CIS formation. Indeed, we detected CXCL12 in Sertoli cells of normal human testis, and relatively high expression in tumour stroma with concomitant weak staining in dispersed tumour cells. In contrast, CXCR4 was expressed in spermatogonial and meiotic germ cells of normal testis and in the majority of tumour cells. Quantitative RT-PCR identified elevated CXCR4 transcript levels in seminoma compared with normal testis and to non-seminoma, potentially reflecting the higher proportion of dysfunctional germ cells within seminomas. In the normal testis, expression of CXCR4 downstream signalling molecules phospho-MEK1/2 and phospho-ERK1/2 correlated with CXCR4/CXCL12 expression. Strikingly, this correlation was absent in seminoma and non-seminoma samples, suggesting that CXCL12 signalling is disrupted. Proliferation rate and cell survival were not altered by CXCL12 in either seminoma (TCam-2) or non-seminoma (833ke) cell lines. However, CXCL12 exposure induced TCam-2 cell invasion though simulated basement membrane, while in contrast, we provide the novel evidence that CXCR4-expressing non-seminoma cell lines 833ke and NTera2/D1 do not invade in response to CXCL12. These findings indicate that CXCL12 expression in the human testis may selectively influence seminoma migration and metastasis, correlating with its importance in gonocyte and spermatogonial stem cell biology.

Australian resident doctors want more palliative medicine education: a survey of attitudes and perceived needs.

Most expected deaths occur in acute hospitals, and medical staff providing end-of-life care are generally not palliative medicine specialists. Through a voluntary self-administered survey, this study explored resident doctors' attitudes to palliative medicine and their perceived educational needs. Fifty-two resident doctors participated (response rate 39%), mostly acknowledging the importance of palliative medicine to their practice and emphasising that further postgraduate education is necessary.

miRNA and mammalian male germ cells.

BACKGROUND Achieving the correct spatial and temporal expression of germ-cell-specific genes is fundamental to the production of viable healthy spermatozoa. Notably, post-transcriptional gene regulation resulting in the repression of protein translation is central to many embryonic processes, and is particularly active during spermatogenesis. In this review, we discuss microRNA (miRNA) regulation of target gene expression in relation to mammalian spermatogenesis, the establishment of testicular germ cell tumours (TGCT) and the potential use of miRNA manipulation for cancer therapy and fertility regulation. METHODS Journal databases such as PubMed were searched using key words, including miRNA, testis, spermatogenesis, germ cell, testicular cancer and cancer. RESULTS In the past decade, the deployment of small non-coding RNA molecules, including miRNA, by the cell, has been recognized as among the most important mechanisms of fine-tuning translational regulation in differentiating cell types. For key regulators of male gametogenesis, high levels of gene expression do not always correspond to elevated levels of protein expression. Cumulatively this indicates that enhancement and repression of post-transcriptional regulatory mechanisms are essential to the success of spermatogenesis. There is also growing evidence that this form of regulation contributes to the aetiology of both TGCT and spermatocytic tumours. CONCLUSIONS miRNA plays an essential role in regulation of genes during the process of spermatogenesis. Disruption of this regulation has the ability to contribute to the neoplastic development of germ cell tumours. However, targeted knockdown of specific miRNA molecules has the potential to form both anti-oncogenic reagents and underpin the basis for novel contraceptive technologies.

Tape transfer sectioning of tissue microarrays introduces nonspecific immunohistochemical staining artifacts.

Tissue microarrays place tens to hundreds of formalin fixed, paraffin embedded tissue cores into a paraffin block in a systematic grid pattern that permits their simultaneous evaluation in a single section. The fragmented nature of the tissue cores often makes sectioning of tissue microarrays difficult so that the resulting disks of tissue lose their shape, fracture or fall out of the paraffin section altogether. We have evaluated an alternative sectioning protocol for stabilizing the tissue microarray surface by placing an adhesive tape "window" over the face of the paraffin block prior to sectioning. Once sectioned, the tape/sections are transferred directly onto coated microscope slides, thereby avoiding routine floating of sections on a water bath. After sectioning with either the tape transfer or standard protocols, slides were stained either using hematoxylin and eosin or immunohistochemistry using antibodies to S-100 protein and the tissue specific antigens, keratin (AE1/3) and the leukocyte common antigen CD45. We found that the tape method produced thicker sections that were darker and more densely packed with loss of tissue definition compared to sections prepared using water bath flotation. Quantitative image analysis of immunohistochemical staining demonstrated that the tape method produced a higher incidence of nonspecific staining, which raised the potential for false positive staining.

Oligodendrocyte degeneration and recovery after focal cerebral ischemia.

The vulnerability of oligodendrocytes to ischemic injury may contribute to functional loss in diseases of central white matter. Immunocytochemical methods to identify oligodendrocyte injury in experimental models rely on epitope availability, and fail to discriminate structural changes in oligodendrocyte morphology. We previously described the use of a lentiviral vector (LV) carrying enhanced green fluorescent protein (eGFP) under the myelin basic protein (MBP) promoter for selective visualization of oligodendrocyte cell bodies and processes. In this study, we used LV-MBP-eGFP to label oligodendrocytes in rat cerebral white matter prior to transient focal cerebral ischemia, and examined oligodendrocyte injury 24 h, 48 h and 1 week post-reperfusion by quantifying cell survival and assaying the integrity of myelin processes. There was progressive loss of GFP+ oligodendrocytes in ischemic white matter at 24 and 48 h. Surviving GFP+ cells had non-pyknotic nuclear morphology and were terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-negative, but there was marked fragmentation of myelin processes as early as 24 h after stroke. One week after stroke, we observed a restoration of GFP+ oligodendrocytes in ischemic white matter, reflected both by cell counts and by structural integrity of myelin processes. Proliferating cells were not the main source of GFP+ oligodendrocytes, as revealed by bromodeoxyuridine (BrdU) incorporation. These observations identify novel transient structural changes in oligodendrocyte cell bodies and myelinating processes, which may have consequences for white matter function after stroke.

Between a rock and a hard place: exploring the conflict between respecting the privacy of patients and informing their carers.

BACKGROUND: A patient's right to privacy is considered fundamental to medical care, with physicians assuming the role of guardian of the clinical information which is conveyed to the patient. However, as a patient's health declines, physicians are often challenged by the need to protect patient privacy while addressing the expectations of the patient's carers, who seek medical information to provide appropriate care at home. AIMS: This study sought to explore the expectations of patients, their carers and physicians regarding the communication of clinical information to carers. METHODS: Surveys were distributed in outpatient clinics at a metropolitan quaternary hospital, with responses from 102 patients and carers, as well as 219 medical staff. RESULTS: The expectations of patients and carers differed from those of medical staff. Physicians typically believed discussions with carers should begin following the patient's permission and at the patient's request. Patients and carers, however, believed information should be automatically offered or provided when questioned. Further, carers generally felt information updates should occur regularly and routinely, whereas physicians indicated updates should occur with prompting either by a major clinical change or in response to a carer's concern. CONCLUSION: Physicians should be aware that the expectations of patients and carers regarding information communication to carers may not match their own. Meanwhile, patients and carers should be made aware of the constraints upon physicians and should be encouraged to convey their preferences for information sharing. These tasks could be facilitated by the development of a prompt sheet to assist the clinical encounter.

The use of economic evaluations in NHS decision-making: a review and empirical investigation.

OBJECTIVES: To determine the extent to which health economic information is used in health policy decision-making in the UK, and to consider factors associated with the utilisation of such research findings. DATA SOURCES: Major electronic databases were searched up to 2004. REVIEW METHODS: A systematic review of existing reviews on the use of economic evaluations in policy decision-making, of health and non-health literature on the use of economic analyses in policy making and of studies identifying actual or perceived barriers to the use of economic evaluations was undertaken. Five UK case studies of committees from four local and one national organisation [the Technology Appraisal Committee of the National Institute for Health and Clinical Excellence (NICE)] were conducted. Local case studies were augmented by documentary analysis of new technology request forms and by workshop discussions with members of local decision-making committees. RESULTS: The systematic review demonstrated few previous systematic reviews of evidence in the area. At the local level in the NHS, it was an exception for economic evaluation to inform technology coverage decisions. Local decision-making focused primarily on evidence of clinical benefit and cost implications. And whilst information on implementation was frequently requested, cost-effectiveness information was rarely accessed. A number of features of the decision-making environment appeared to militate against emphasis on cost-effectiveness analysis. Constraints on the capacity to generate, access and interpret information, led to a minor role for cost-effectiveness analysis in the local decision-making process. At the national policy level in the UK, economic analysis was found to be highly integrated into NICE's technology appraisal programme. Attitudes to economic evaluation varied between committee members with some significant disagreement and extraneous factors diluted the health economics analysis available to the committee. There was strong evidence of an ordinal approach to consideration of clinical effectiveness and cost-effectiveness information. Some interviewees considered the key role of a cost-effectiveness analysis to be the provision of a framework for decision-making. Interviewees indicated that NICE makes use of some form of cost-effectiveness threshold but expressed concern about its basis and its use in decision-making. Frustrations with the appraisal process were expressed in terms of the scope of the policy question being addressed. Committee members raised concerns about lack of understanding of the economic analysis but felt that a single measure of benefit, e.g. the quality-adjusted life-year, was useful in allowing comparison of disparate health interventions and in providing a benchmark for later decisions. The importance of ensuring that committee members understood the limitations of the analysis was highlighted for model-based analyses. CONCLUSIONS: This study suggests that research is needed into structures, processes and mechanisms by which technology coverage decisions can and should be made in healthcare. Further development of 'resource centres' may be useful to provide independent published analyses in order to support local decision-makers. Improved methods of economic analyses and of their presentation, which take account of the concerns of their users, are needed. Finally, the findings point to the need for further assessment of the feasibility and value of a formal process of clarification of the objectives that we seek from investments in healthcare.

Addiction.

Alcohol and psycho-active substance misuse has far-reaching social, psychological and physical consequences. Advances in neuroimaging technology have allowed neurobiological theories of addiction to become better characterized. We describe the neurobiology of dependence, withdrawal, abstinence and craving states in alcohol, stimulant and opiate misuse. Structural neuroimaging techniques such as CT and MRI with new analytical approaches such as voxel-based morphometry have shown wide-spread changes in stimulant and opiate abuse and atrophy, particularly in the frontal lobes, in alcoholism. Functional neuroimaging techniques such as PET, SPECT and fMRI reveal altered regional cerebral activity by all drugs of abuse. The neurochemistry of addiction, particularly involving dopamine, serotonin, opiate and GABA, has been studied with PET and SPECT and similarities between all drugs of abuse have been found such as reduced dopaminergic markers. The evidence derived from these advances in neuroimaging is likely to herald the emergence of new biological treatments in this important field.

Public perceptions. The generation claim.

There is a growing perception that support for the NHS is falling off among the young. The evidence for this is not conclusive. Dissatisfaction with the NHS is more likely to be linked to increased expectations rather than lack of social solidarity.

Public consultation. Consulting room.

The government's consultation exercise over the NHS was rare in attempting to capture the views of a large number of citizens other than through a survey. The exercise raised questions about whether or not the government had a plan for the NHS. In the long term, the government may have to consult the public in the context of rationing.

Treatment decisions. Whys and wherefores.

A review of challenges to five health authorities' refusals to fund treatment found none of the health authorities had an explicit process for decision making which would stand up to public scrutiny. None had an appeals procedure for contested decisions. This will become an issue for primary care groups and trusts as they will face the same challenges as HAs which refuse treatment. There is the added complication that the doctors will be acting both as agents for their patients and stewards of the resources for the community of patients they serve. Where there are restrictions on treatment, conflict might be avoided by the use of widely available guidelines. Dilemmas over refusing individual patients treatment will not be entirely resolved by evidence-based decisions.

Expert patients. So you think you know it all?

The government's proposal to set up an expert patients programme to enable those with chronic illnesses and disabilities to manage their condition is a welcome step towards greater user involvement. The programme should avoid a medical model and take account of patients' social circumstances. The programme must include evaluation. Health professionals in the UK have yet to embrace patient self-management. To date they have been reluctant to refer service users to self-help groups.

Patient surveys. There for the asking.

The government's proposal to survey 100,000 patients a year in order to improve services faces considerable organisational problems. We estimate it will cost 200,000 pounds a year. The simple opinion poll approach should be avoided in favour of a detailed questionnaire. A rolling programme of surveys in specific service areas might be more meaningful than a comprehensive annual survey. The aims of capturing patients' views and comparing performance across the country could prove incompatible.

Information for public choice.

The kind of information the public will need in order to take part in the rationing debate is examined. The public are interested in the debate both as taxpayers and as patients and they can have an input in a number of different ways. Their involvement at the level of general discussions about values and service priorities is problematic, because some of the methods used do not allow participants to ask questions or work through the implications of the information they have access to. The mechanisms for ensuring their involvement in planning service strategies are better known and the information requirements are clear. When patients are given more say in decisions about their treatment and care, they may choose different options to those favoured by health professionals, but more work still needs to be done on developing and presenting complex medical information and helping patients to make decisions.

The role of psychologists in the treatment, management, and prevention of chronic mental illness.

In addition to suffering from the severe psychiatric symptoms of chronic mental illness (CMI), people with this type of disorder suffer from a variety of secondary disabilities and face societal obstacles that interfere with their ability to maximize their personal, social, and vocational potentials. Following the deinstitutionalization of long-term psychiatric patients in recent decades, many different understandings of the etiology, treatment, and management of CMI have evolved, including those derived from the biological, vulnerability, cognitive, case management, rehabilitation, and psychoeducational models. Because psychologists are trained in a wide range of psychological theories and a broad repertoire of applications, they have unique contributions to make within each model, particularly, as discussed here, to prevent, treat, and manage CMI through research, assessment, and intervention.