MST1 DOWNREGULATES TAZ TUMOUR SUPPRESSOR PROTEIN IN MULTIPLE MYELOMA AND IS A POTENTIAL THERAPEUTIC TARGET

We have previously reported that TAZ functions as a tumor suppressor in multiple myeloma. MST1 is a serine-threonine kinase upstream of the Hippo-signaling pathway that functions as a tumor suppressor in many non-haematological malignancies. However, its role in hematological malignancies, including MM is still poorly understood. In this paper, we provide evidence that MST1 expression is higher in MM, and negatively correlates with TAZ expression in both cell lines and patient samples. High MST1 expression was associated with poor clinical outcomes. Genetic or pharmacological inhibition of MST1 leads to increased TAZ expression and cell death. Importantly, MST1 inhibitors sensitizes myeloma cells to frontline antimyeloma agent-lenalidomide and dexamethasone. Taken together, our data reveals a key role for MST1 in MM pathogenesis and provide evidence to explore the therapeutic potential of using MST inhibitors to upregulate TAZ expression in MM to promote response to anticancer agents.

Clinical imaging of hypoxia: Current status and future directions

Tissue hypoxia is a key feature of many important causes of morbidity and mortality. In pathologies such as stroke, peripheral vascular disease and ischaemic heart disease, hypoxia is largely a consequence of low blood flow induced ischaemia, hence perfusion imaging is often used as a surrogate for hypoxia to guide clinical diagnosis and treatment. Importantly, ischaemia and hypoxia are not synonymous conditions as it is not universally true that well perfused tissues are normoxic or that poorly perfused tissues are hypoxic. In pathologies such as cancer, for instance, perfusion imaging and oxygen concentration are less well correlated, and oxygen concentration is independently correlated to radiotherapy response and overall treatment outcomes. In addition, the progression of many diseases is intricately related to maladaptive responses to the hypoxia itself. Thus there is potentially great clinical and scientific utility in direct measurements of tissue oxygenation. Despite this, imaging assessment of hypoxia in patients is rarely performed in clinical settings. This review summarises some of the current methods used to clinically evaluate hypoxia, the barriers to the routine use of these methods and the newer agents and techniques being explored for the assessment of hypoxia in pathological processes.

Collaborative research networks in health: a pragmatic scoping study for the development of an imaging network

Background

Collaborative research networks are often touted as a solution for enhancing the translation of knowledge, but questions remain about how to evaluate their impact on health service delivery. This pragmatic scoping study explored the enabling factors for developing and supporting a collaborative imaging network in a metropolitan university in Australia.

Methods

An advisory group was established to provide governance and to identify key informants and participants. Focus group discussions (n = 2) and semi-structured interviews (n = 22) were facilitated with representatives from a broad range of disciplines. In addition, a survey, a review of relevant websites (n = 15) and a broad review of the literature were undertaken to elicit information on collaborative research networks and perceived needs and factors that would support their involvement in a multi-disciplinary collaborative research network. Findings were de-identified and broad themes were identified.

Results

Participants identified human factors as having priority for developing and sustaining a collaborative research network. In particular, leadership, a shared vision and a communication plan that includes social media were identified as crucial for sustaining an imaging network in health research. It is important to develop metrics that map relationships between network members and the role that communication tools can contribute to this process.

Conclusions

This study confirms that human factors remain significant across a range of collaborative endeavours. The use of focus group discussions, interviews, and literature and website reviews means we can now strongly recommend the primacy of human factors. More work is needed to identify how the network operates and what specific indicators or metrics help build the capacity of clinicians and scientists to participate in translational research.

Improving the diagnosis of LV non-compaction with cardiac magnetic resonance imaging

BACKGROUND

Current diagnostic criteria for left ventricular non-compaction (LVNC) poorly correlate with clinical outcomes. We aimed to develop a cardiac magnetic resonance (CMR) based semi-automated technique for quantification of non-compacted (NC) and compacted (C) masses and to ascertain their relationships to global and regional LV function.

METHODS

We analysed CMR data from 30 adults with isolated LVNC and 20 controls. NC and C masses were measured using relative signal intensities of myocardium and blood pool. Global and regional LVNC masses was calculated and correlated with both global and regional LV systolic function as well as occurrence of arrhythmia.

RESULTS

LVNC patients had significantly higher end-systolic (ES) and end-diastolic (ED) NC:C ratios compared to controls (ES 0.21 [SD 0.09] vs. 0.12 [SD 0.02], p<0.001; ED 0.39 [SD 0.08] vs. 0.26 [SD 0.05], p<0.001). NC:C ratios correlated inversely with global ejection fraction, with a stronger correlation in ES vs. ED (r=-0.58, p<0.001 vs. r=-0.30, p=0.03). ES basal, mid and apical NC:C ratios also showed a significant inverse correlation with global LV ejection fraction (ES basal r=-0.29, p=0.04; mid-ventricular r=-0.50, p<0.001 and apical r=-0.71, p<0.001). Upon ROC testing, an ES NC:C ratio of 0.16 had a sensitivity of 70% and a specificity of 95% for detection of significant LVNC. Patients with sustained ventricular tachycardia had a significantly higher ES NC:C ratio (0.31 [SD 0.18] vs. 0.20 [SD 0.06], p=0.02).

CONCLUSIONS

The NC:C ratio derived from relative signal intensities of myocardium and blood pool improves the ability to detect clinically relevant NC compared to previous CMR techniques.

Brain volumetric, regional cortical thickness and radiographic findings in adults with cyanotic congenital heart disease

Background

Chronic cyanosis in adults with congenital heart disease (CHD) may cause structural brain changes that could contribute to impaired neurological functioning. The extent of these changes has not been adequately characterized.

Hypothesis

We hypothesized that adults with cyanotic CHD would have widespread changes including abnormal brain volumetric measures, decreased cortical thickness and an increased burden of small and large vessel ischemic changes.

Methods

Ten adults with chronic cyanosis from CHD (40 ± 4 years) and mean oxygen saturations of 82 ± 2% were investigated using quantitative MRI. Hematological and biochemical parameters were also assessed. All subjects were free from major physical or intellectual impairment. Brain volumetric results were compared with randomly selected age- and sex-matched controls from our database of normal subjects.

Results

Five of 10 cyanotic subjects had cortical lacunar infarcts. The white matter (WM) hyperintensity burden was also abnormally high (Scheltens Scale was 8 ± 2). Quantitative MRI revealed evidence of extensive generalized WM and gray matter (GM) volumetric loss; global GM volume was reduced in cyanosed subjects (630 ± 16 vs. 696 ± 14 mL in controls, p = 0.01) as was global WM volume (471 ± 10 vs. 564 ± 18 mL, p = 0.003). Ventricular cerebrospinal fluid volume was increased (35 ± 10 vs. 26 ± 5 mL, p = 0.002). There were widespread regions of local cortical thickness reduction observed across the brain. These changes included bilateral thickness reductions in the frontal lobe including the dorsolateral prefrontal cortex and precentral gyrus, the posterior parietal lobe and the middle temporal gyrus. Sub-cortical volume changes were observed in the caudate, putamen and in the thalamus (p ≤ 0.005 for all regions). Cortical GM volume negatively correlated with brain natriuretic peptide (R = − 0.89, p = 0.009), high sensitivity C-reactive protein (R = − 0.964, p < 0.0001) and asymmetric dimethylarginine (R = − 0.75, p = 0.026) but not with oxygen saturations, packed cell volume or viscosity.

Conclusions

We present the first comprehensive analysis of brain structure in adults with chronic neurocyanosis due to congenital heart disease. We demonstrate clear evidence for marked macro- and microvascular injury. Cyanotic patients show global evidence for reduced brain volume as well as specific foci of cortical thickness reduction. The GM volume loss correlated with hsCRP, BNP and ADMA suggesting that inflammation, neurohormonal activation and endothelial dysfunction may have important roles in its pathogenesis.

•

A high burden of cerebral small and large vessel ischemic injury.

•

Extensive white and gray matter (GM) volumetric loss.

•

Regions of bilateral local cortical thickness reduction within the frontal, parietal and temporal lobes.

Brain derived neurotrophic factor Val66Met polymorphism, the five factor model of personality and hippocampal volume: Implications for depressive illness

Altered hippocampal volume, the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism, and neuroticism have each been implicated in the etiology of psychiatric disorders, especially depression. However, the relationship between these variables is not well understood. Here, we determined the effects of the BDNF Val66met polymorphism on the five-factor personality dimensions (assessed using the NEO-FFI), trait depression (assessed with the DASS-21) in a cross-sectional cohort of 467 healthy volunteers. A large matched subset of this cohort was also assessed for grey matter volume of the hippocampus and contiguous temporal cortical regions using magnetic resonance imaging. In Met carriers, elevations in neuroticism and trait depression and stress were associated with lower mean hippocampal volume, but there were no such associations in Val homozygotes. Trait depression, in particular, was found to moderate the effects of BDNF genotypes on hippocampal volume. Met carriers with high trait depression showed a reduction in grey matter volume of the mean hippocampus compared with Val homozygotes. These findings suggest that even in otherwise healthy subjects, trait depression may contribute to the susceptibility of Met carriers to hippocampal grey matter loss.

Disturbances in selective information processing associated with the BDNF Val66Met polymorphism: evidence from cognition, the P300 and fronto-hippocampal systems

In this study, we examined whether the Met allele of the BDNF Val66Met polymorphism is associated with selective disruptions to task-relevant information processing. In 475 non-clinical participants for whom BDNF genotype status was determined we used the 'IntegNeuro' computerized battery of neuropsychological tests to assess cognitive performance, an auditory oddball task to elicit the P300 event-related potential (ERP) and, in smaller subsets of these subjects, high resolution structural MRI imaging to quantify fronto-hippocampal grey matter (n=161), and functional magnetic resonance imaging to assess fronto-hippocampal BOLD activation (n=37). Met/Met (MM) homozygotes had higher verbal recall errors, in the absence of differences in attention, executive function, verbal ability or sensori-motor function. Further, MM homozygotes demonstrated a slowed P300 ERP during the oddball task, with corresponding alterations in hippocampal and lateral prefrontal activation, and a localized reduction in hippocampal grey matter. These results are consistent with a subtle impact of the Met allele on fronto-hippocampal systems involved in selective information processing of stimulus context and memory updating within the normal population. The findings also indicate that heritable endophenotypes such as the P300 have value in elucidating genotype-phenotype relationships.

Early life stress and morphometry of the adult anterior cingulate cortex and caudate nuclei

BACKGROUND

Early life stress (ELS) is linked to adult psychopathology and may contribute to long-term brain alterations, as suggested by studies of women who suffered childhood sexual abuse. We examine whether reported adverse ELS defined as stressful and/or traumatic adverse childhood events (ACEs) is associated with smaller limbic and basal ganglia volumes.

METHOD

265 healthy Australian men and women without psychopathology or brain disorders were studied. ACEs were assessed by the ELSQ and current emotional state by the DASS. Anterior cingulate cortex (ACC), hippocampus, amygdala, and caudate nucleus volumes were measured from T1-weighted MRI. Analyses examined ROI volumetric associations with reported ACEs and DASS scores.

RESULTS

Participants with greater than two ACEs had smaller ACC and caudate nuclei than those without ACEs. A significant association between total ACEs and ROI volumes for these structures was observed. Regression analysis also revealed that ELS was more strongly associated than current emotional state (DASS) with these ROI volumes.

CONCLUSIONS

Reported ELS is associated with smaller ACC and caudate volumes, but not the hippocampal or amygdala volumes. The reasons for these brain effects are not entirely clear, but may reflect the influence of early stress and traumatic events on the developing brain.

Orientational order of Australian spider silks as determined by solid-state NMR

A simple solid-state NMR method was used to study the structure of (13)C- and (15)N-enriched silk from two Australian orb-web spider species, Nephila edulis and Argiope keyserlingi. Carbon-13 and (15)N spectra from alanine- or glycine-labeled oriented dragline silks were acquired with the fiber axis aligned parallel or perpendicular to the magnetic field. The fraction of oriented component was determined from each amino acid, alanine and glycine, using each nucleus independently, and attributed to the ordered crystalline domains in the silk. The relative fraction of ordered alanine was found to be higher than the fraction of ordered glycine, akin to the observation of alanine-rich domains in silk-worm (Bombyx mori) silk. A higher degree of crystallinity was observed in the dragline silk of N. edulis compared with A. keyserlingi, which correlates with the superior mechanical properties of the former.

Electromagnetic characterisation of MR RF coils using the transmission-line modelling method

The Transmission-Line Modelling (TLM) method is applied to the electromagnetic characterisation of RF coils and samples for magnetic resonance imaging MRI. Theoretical verification was performed using a simple surface coil. Experimental verification was performed using Alderman-Grant and birdcage coils constructed for use on a 7 T micro-imaging system. The modelling method enabled electromagnetic characteristics of frequency response, electromagnetic field generation, energy stored and power loss to be determined. From these parameters, coil resonant modes, B1 field profiles, voltages, currents, quality factor (Q), pi/2 pulse length, and the equivalent lumped-element circuit components of resistance, inductance and capacitance were calculated. Equations are presented that enable a comprehensive electromagnetic characterisation of the RF coil and sample to be achieved based on the results of the TLM simulations. The use of the TLM method is extended to include the design of safe arbitrary multi-nuclear pulse sequences such that the specific absorption rate (SAR) of tissue, and RF coil component safety limits are not exceeded.

Prenatal education for mothers with disabilities

Prenatal nurse educators are well prepared to meet the learning needs of many expectant mothers. But how prepared are they to meet the learning needs of mothers with disabilities? To answer this question, eight mothers with various chronic illnesses located in north-eastern Ontario, Canada were asked to describe their maternity experiences. Given the small convenience sample and exploratory nature of the study, a qualitative content analysis was done. The mothers' reports described interaction with a variety of health professionals. This analysis focuses on findings specific to nurses who provide prenatal education. In general, mothers reported they had received insufficient, inappropriate information, especially about their pregnancy and chronic illnesses. The mothers thought that nurses doubted the ability of women with disabilities to be decision-makers or responsible and 'proper' mothers. Suggestions by disabled mothers for quality care in prenatal education are described. A more emancipatory approach to preparing nurses for practice as prenatal educators is recommended. Such an approach can reduce the barriers associated with power differences between women with disabilities as 'learners' and their nurse 'teachers'.

Local and systemic effects of intra-arterial desmopressin in healthy volunteers and patients with type 3 von Willebrand disease. Role of interleukin-6

Intra-arterial desmopressin caused dose and time dependent increases (p <0.001 for all) in forearm blood flow (all doses) and plasma tissue plasminogen activator (t-PA) concentrations (desmopressin > or = 70 ng/min). Although plasma t-PA concentrations rose in both forearms, there was a modest local release of t-PA in the infused forearm (14 ng/100 mL of tissue/min, p <0.05). At desmopressin doses > or = 300 ng/min, plasma von Willebrand factor (vWf) and Factor VIII:C concentrations rose in both forearms (p <0.001) and correlated with the rise in interleukin-6 concentrations (r = 0.92, p <0.001: r = 0.85, p = 0.002 respectively). Neither desmopressin nor substance P caused t-PA, vWf or Factor VIII:C release in the patients, although desmopressin increased plasma interleukin-6 concentrations as in healthy volunteers. We conclude that desmopressin releases t-PA, vWf and Factor VIII:C predominantly via systemic mechanisms, possibly mediated by cytokine release. Patients with type 3 vWD appear to have a generalised failure to release t-PA acutely despite a normal interleukin-6 response to desmopressin infusion.

Measuring morale--does practice area deprivation affect doctors' well-being?

BACKGROUND

Morale is a perennial concern in general practice and, over the years, a variety of tools have been used to examine doctors' mental well-being in a range of psychological and sociological studies. Despite perceived associations between low morale and practice area deprivation, this has not been investigated previously.

AIM

To devise and apply a measure of mental well-being in general practitioners, and to use this to investigate the effect of practice area deprivation.

METHOD

A questionnaire was devised and piloted, then used in an anonymous postal survey of a random sample of 500 London general practitioners, with questions on demography, workload, practice characteristics, patient centredness, and practice area deprivation.

RESULTS

A total of 334 (68%) doctors replied to the questionnaire. Of these, 45% often feel exhausted, 46% are often frustrated by trivial consultations, and a third are seriously disenchanted with work. The resulting well-being score had a normal distribution, was reproducible (test-retest reliability = 0.91), and was internally consistent (Cronbach's alpha = 0.76). Comments from respondents suggested good face validity. Low well-being was not associated with practice area deprivation, but was associated with time stress, small practices and primary care teams, and lack of patient centredness.

CONCLUSION

The instrument provided a useful tool for examining doctors' well-being and the associations thereof. Well-being was not associated with practice area deprivation. Help for small primary care teams and measures to reduce time stress should help to improve morale.

Alpha-chain disease in a non-Mediterranean climate. A case report

The clinical, biochemical, immunological and histopathological features in a patient with alpha-chain disease are described. The patient, a 20-year-old Coloured man, presented with severe steatorrhoea, malabsorption, abdominal pain and progressive general deterioration. An heterogeneous abnormal band with IgA immunochemical specificity was detected on electrophoresis of the patient's serum and urine. This protein was identified as free alpha-chain and was present in serum, urine, saliva and jejunal juice. A jejunal mucosal biopsy specimen showed distinctive appearances associated with alpha-chain disease. Bone marrow involvement was found and abnormal lymphoid cells were seen in the circulation together with an increased B lymphocyte population derived from bone marrow. This is the third South African patient with alpha-chain disease to be diagnosed. The patient has shown a partial remission after 12 months' chemotherapy. There was rapid symptomatic response and normalisation of protein parameters which were not paralleled by an objectively discernible response as assessed by haematological examination, intestinal absorption studies and histology of the jejunal mucosa.