Future trends in measuring physiology in free-living animals.

Thus far, ecophysiology research has predominantly been conducted within controlled laboratory-based environments, owing to a mismatch between the recording technologies available for physiological monitoring in wild animals and the suite of behaviours and environments they need to withstand, without unduly affecting subjects. While it is possible to record some physiological variables for free-living animals using animal-attached logging devices, including inertial-measurement, heart-rate and temperature loggers, the field is still in its infancy. In this opinion piece, we review the most important future research directions for advancing the field of 'physiologging' in wild animals, including the technological development that we anticipate will be required, and the fiscal and ethical challenges that must be overcome. Non-invasive, multi-sensor miniature devices are ubiquitous in the world of human health and fitness monitoring, creating invaluable opportunities for animal and human physiologging to drive synergistic advances. We argue that by capitalizing on the research efforts and advancements made in the development of human wearables, it will be possible to design the non-invasive loggers needed by ecophysiologists to collect accurate physiological data from free-ranging animals ethically and with an absolute minimum of impact. In turn, findings have the capacity to foster transformative advances in human health monitoring. Thus, we invite biomedical engineers and researchers to collaborate with the animal-tagging community to drive forward the advancements necessary to realize the full potential of both fields. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.

Asymmetric energetic costs in reciprocal-cross hybrids between carnivorous mice (Onychomys).

Aerobic respiration is a fundamental physiological trait dependent on coordinated interactions between gene products of the mitochondrial and nuclear genomes. Mitonuclear mismatch in interspecific hybrids may contribute to reproductive isolation by inducing reduced viability (or even complete inviability) due to increased metabolic costs. However, few studies have tested for effects of mitonuclear mismatch on respiration at the whole-organism level. We explored how hybridization affects metabolic rate in closely related species of grasshopper mice (genus Onychomys) to better understand the role of metabolic costs in reproductive isolation. We measured metabolic rate across a range of temperatures to calculate basal metabolic rate (BMR) and cold-induced metabolic rate (MRc) in O. leucogaster, O. torridus and O. arenicola, and in reciprocal F1 hybrids between the latter two species. Within the genus, we found a negative correlation between mass-specific BMR and body mass. Although O. arenicola was smaller than O. torridus, hybrids from both directions of the cross resembled O. arenicola in body mass. In contrast, hybrid BMR was strongly influenced by the direction of the cross: reciprocal F1 hybrids were different from each other but indistinguishable from the maternal species. In addition, MRc was not significantly different between hybrids and either parental species. These patterns indicate that metabolic costs are not increased in Onychomys F1 hybrids and, while exposure of incompatibilities in F2 hybrids cannot be ruled out, suggest that mitonuclear mismatch does not act as a primary barrier to gene flow. Maternal matching of BMR is suggestive of a strong effect of mitochondrial genotype on metabolism in hybrids. Together, our findings provide insight into the metabolic consequences of hybridization, a topic that is understudied in mammals.

Symptoms of Raynaud's phenomenon (RP) in fibromyalgia syndrome are similar to those reported in primary RP despite differences in objective assessment of digital microvascular function and morphology.

Symptoms of Raynaud's phenomenon (RP) are common in fibromyalgia syndrome (FMS). We compared symptom characteristics and objective assessment of digital microvascular function using infrared thermography (and nailfold capillaroscopy where available) in patients with FMS (reporting RP symptoms) and primary RP. We retrospectively reviewed the outcome of microvascular imaging studies and RP symptom characteristics (captured using patient-completed questionnaire at the time of assessment) for patients with FMS (reporting RP symptoms) and patients with primary RP referred for thermographic assessment of RP symptoms over a 2-year period. Of 257 patients referred for thermographic assessment of RP symptoms between 2010 and 2012, we identified 85 patients with primary RP and 43 patients with FMS. There were no differences in RP symptom characteristics between FMS and primary RP (p > 0.05 for all comparisons). In contrast, patients with FMS had higher baseline temperature of the digits (32.1 vs. 29.0 °C, p = 0.004), dorsum (31.9 vs. 30.2 °C, p = 0.005) and thermal gradient (temperature of digits minus temperature of dorsum; +0.0 vs. -0.9 °C, p = 0.03) compared with primary RP. Significant differences between groups persisted following local cold challenge. In primary RP, patient reporting "blue" digits, bi-phasic and tri-phasic RP was associated with lower digital perfusion. In contrast, no associations between skin temperature and RP digital colour changes/phases were identified in FMS. Our findings suggest that symptoms of RP in FMS may have a different aetiology to those seen in primary RP. These findings have potential implications for both the classification of RP symptoms and the management of RP symptoms in the context of FMS. Digital colour changes reported by patients might reflect the degree of digital microvascular compromise in primary RP.

Comparison of infrared thermography and laser speckle contrast imaging for the dynamic assessment of digital microvascular function.

OBJECTIVES: Laser speckle contrast imaging (LSCI) is a novel non-invasive microvascular imaging modality. The present study evaluates the validity and reliability of LSCI by comparison with infrared thermography (IRT) for the dynamic assessment of digital microvascular function in healthy volunteers. METHODS: Subjects attended on 3 occasions. Simultaneous assessment of cutaneous perfusion at 3 distinct regions of interest (ROI) within the hands was undertaken using LSCI and infrared thermography (IRT) at baseline, and at 13s intervals over 15 min following a standardised local cold challenge. Endpoints for evaluation included absolute measurements at baseline and following cold stress, in addition to the characteristics of the re-warming curves (maximum % recovery and maximum gradient). Visits 1 and 2 were undertaken in identical conditions (ambient temperature 23°C) to assess reproducibility, whereas visit 3 was undertaken at a lower ambient room temperature of 18°C to evaluate responsiveness to reduction in ambient room temperature. RESULTS: Fourteen healthy participants completed the study. There was greater variability in the data generated using LSCI compared with the highly damped IRT, reflecting greater sensitivity of LSCI to physiological variation and movement artefact. LSCI and IRT correlated well at baseline and following cold challenge for all endpoints (r(s) for pooled data between 0.5 and 0.65, p<0.00005). Reproducibility of both IRT and LSCI was excellent (ICCs>0.75) for absolute assessments but lower for re-warming curve characteristics. LSCI provides greater spatial resolution than IRT identifying variation in cutaneous perfusion within the hands most likely associated with the presence of arteriovenous anastamoses. Both techniques were responsive to reduction in ambient room temperature. Effect sizes were greatest for IRT than LSCI (e.g. -1.17 vs. -0.85 at ROI 1 at baseline) although this may represent heat transfer rather than altered vascular perfusion. DISCUSSION: In the dynamic assessment of digital vascular perfusion, LSCI correlates well with IRT, is reproducible and responsive to reduction in ambient room temperature. Absolute measurements appear preferable to parameters derived from re-warming curve characteristics when assessing digital perfusion following cold challenge. The greater temporal and spatial resolution of LSCI compared with IRT may facilitate the development of novel assessment tools of autonomic function and digital cutaneous perfusion.

Influence of the cold challenge on the discriminatory capacity of the digital distal-dorsal difference in the thermographic assessment of Raynaud's phenomenon.

OBJECTIVES: To investigate the influence of a standardised cold stress test (CST) on the thermographic 'distal-dorsal difference' (DDD) and its capacity to differentiate between disease states in the assessment of Raynaud's phenomenon (RP), and to compare the discriminatory capacity of the DDD of individual digits with composite indices of multiple digits. METHODS: Thermographic images of 55 patients with primary RP (PRP, n=27) and systemic sclerosis (SSc, n=28) who had undergone assessment of RP were retrospectively reviewed. The DDD for individual digits, and composite scores of multiple digits, were calculated at baseline (23°C), and at 10 min following CST. The discriminatory capacity of the mean DDD, and the proportion of patients with a clinically meaningful DDD of <-1°C, were assessed for individual digits and composite indices, at baseline and following cold challenge. RESULTS: There was a more pronounced decrease of the DDD (indicating reduced distal perfusion) following CST in patients with PRP compared to SSc. The disparity in response to CST between groups narrowed the differences that were present at baseline, reducing the discriminatory capacity of the DDD for all endpoints. Sparing of the thumbs occurs to a greater extent in SSc (P<0.005) compared with PRP (P<0.05) but does not facilitate differentiation between groups. Large variability of the DDD within groups precludes easy differentiation between disease states. Composite indices of multiple digits are preferable to individual digital assessment. CONCLUSIONS: The discriminatory capacity of the DDD is lost following CST. The CST may not be essential in the thermographic assessment of RP, potentially allowing greater use of thermography in clinical practise.

Rhabdomyosarcoma subtyping by immunohistochemical assessment of myogenin: tissue array study and review of the literature.

Myogenin immunostaining has been described as a useful marker of the alveolar subtype of rhabdomyosarcoma and as a tool for distinguishing it from the more common embryonal subtype. To add to the growing body of literature describing this phenomenon we analysed myogenin immunohistochemical staining in 152 tumors using a rhabdomyosarcoma tissue array. Results were analysed blinded to histological type by two independent investigators. Samples were excluded if any samples failed to stain with desmin and/or myogenin. Mean percentage of myogenin positive cells was significantly greater for ARMS (n = 31; mean percentage positivity 59% (95% confidence intervals +/- 7%) than ERMS (n = 41, mean percentage positivity 16%, 95% confidence intervals +/- 4; P < 0.0001). This data is consistent with previously published studies identifying strong nuclear myogenin staining in a high proportion of cells as a marker of alveolar histology.

Evaluation of 24-color multifluor-fluorescence in-situ hybridization (M-FISH) karyotyping by comparison with reverse chromosome painting of the human breast cancer cell line T-47D.

Multifluor-fluorescence in-situ hybridization (M-FISH) chromosome paints for all the chromosomes in the human complement labeled with different combinations of fluorochromes is a recent technological development enabling assignment of chromosomal material to rearranged chromosomes. Little data is available on the accuracy and limitations of the approach to the analysis of complex karyotypes, which are characteristic of many malignant diseases. Here we compare M-FISH analysis of the breast-cancer-derived cell line T-47D with a previous analysis by reverse chromosome painting analysis of flow-sorted chromosomes from the same material. This demonstrated a high degree of concordance. It also illustrated the limitations of M-FISH analysis, including difficulties identifying small regions of chromosomal material and intrachromosomal rearrangements. Confirmation of selected aberrations using less-complex mixtures of painting probes and further definition of abnormalities using single copy markers may be required. The detailed karyotype description possible by M-FISH analysis contrasts with the definition in the original G-banding analysis. This and the level of concordance with reverse FISH painting supports the utility of the approach in the definition of complex karyotypes.

Neuropsychological assessment and EEG sleep in affective disorders.

The neuropsychological test performance of 76 hospitalized, depressed patients meeting RDC for the presence of affective disorder was assessed as part of a protocol involving amitryptyline (n = 53) or placebo (n = 23). Tests included the Trail-making Test (TMT), the Benton Visual Retention Test, and the Shipley-Hartford Scale. Clinical ratings and data concerning the characteristics of EEG sleep were also obtained. Analysis of data collected after a drug-free period of 2 weeks and again at the end of the protocol yielded the following conclusions. Base-line performance was inferior to norms for these tests, but for the TMT, scores were not as poor as that expected for brain-damaged patients. Poor performance was often associated with older age, the presence of psychotic features, and prolonged sleep latencies. Baseline Hamilton Rating Scale (HRS) was predicted best by TMT part B. However, this association was not as strong as that between HRS and poor sleep efficiency. Treatment with drug or placebo had little differential effect upon test performance over the course of the protocol. It is suggested that further research should utilize tests which have specificity in localizing cerebral lesions, so that any focal deficits in brain function in depression might be identified.