Photodynamic therapy, mediated by exogenously administered aminolevulinic acid (ALA-PDT) followed by exposure to a laser or broadband light source, is a promising modality for treatment of many types of cancers, but it remains inadequate to treat large, deep solid tumors. Here we report that calcitriol, the active form of Vitamin D3, can be administered prior to ALA as a non-toxic preconditioning regimen to markedly increase the efficacy of ALA-PDT. Using mouse models of squamous skin cancer for preclinical proof of concept, we showed that calcitriol delivered topically or intraperitoneally increased tumoral accumulation of the PDT-activated ALA product protoporphyrin-IX (PpIX) up to 10-fold, mainly by altering expression of the porphyrin synthesis enzymes coproporphyrinogen oxidase (increased) and ferrochelatase (decreased). Calcitriol-pretreated tumors underwent enhanced apoptotic cell death following ALA-based PDT. Mechanistic studies documented activation of the extrinsic apoptotic pathway, with specific cleavage of caspase-8 and increased production of TNFα in tumors preconditioned by calcitriol treatment before ALA-PDT. Very low doses of calcitriol (0.1–1 µg/kg body weight) were sufficient to elicit tumor-selective enhancement to ALA-PDT efficacy, rendering toxicity concerns negligible. Our findings define a simple, non-toxic and highly effective preconditioning regimen to enhance the response of epithelial tumors to ALA-PDT, possibly broadening its clinical applications by selectively enhancing accumulation of photosensitizer PpIX along with TNFα in tumors.

Objective: To quantify Diabetes Alert Dog (DAD) performance by using owner-independent measures. Research Design and Methods: Eight owners of accredited DADs used a FreeStyle Libre Flash Glucose Monitoring System (FGMS). Concurrent Closed Circuit Television (CCTV) footage was collected for between 5 and 14 days in each owner's home or workplace. The footage was blind-coded for dogs' alerting behaviors. The sensitivity, False Positive Rate and Positive Predictive Values (PPV) of dogs' alerts to out-of-range (OOR) episodes were calculated. Ratings for 11 attributes describing participant's lifestyle and compliance (taken from each dog's instructor) and the percentage of DAD alerts responded to by the owner as per training protocol (taken from CCTV footage) were assessed for association with dog performance. Results: Dogs alerted more often when their owners' glucose levels were outside vs . inside target range (hypoglycaemic 2.80-fold, p = 0.001; hyperglycaemic 2.29-fold, p = 0.005). Sensitivity to hypoglycaemic episodes ranged from 33.3 to 91.7%, the mean was 55.9%. Mean PPV for OOR episodes was 69.7%. Sensitivity and PPV were associated with aspects of the dog and owner's behavior, and the owner's adherence to training protocol. Conclusions: Owner-independent methods support that some dogs alert to hypo- and hyperglycaemic events accurately, but performance varies between dogs. We find that DAD performance is affected by traits and behaviors of both the dog and owner. Combined with existing research showing the perceived psychosocial value and reduced critical health care needs of DAD users, this study supports the value of a DAD as part of a diabetes care plan. It also highlights the importance of ongoing training and continued monitoring to ensure optimal performance.

Signals of dominance and submissiveness are central to conspecific communication in many species. For domestic animals, sensitivities to these signals in humans may also be beneficial. We presented domestic horses with a free choice between two unfamiliar humans, one adopting a submissive and the other a dominant body posture, with vocal and facial cues absent. Horses had previously been given food rewards by both human demonstrators, adopting neutral postures, to encourage approach behaviour. Across four counterbalanced test trials, horses showed a significant preference for approaching the submissive posture in both the first trial and across subsequent trials, and no individual subject showed an overall preference for dominant postures. There was no significant difference in latency to approach the two postures. This study provides novel evidence that domestic horses may spontaneously discriminate between, and attribute communicative significance to, human body postures of dominance; and further, that familiarity with the signaller is not a requirement for this response. These findings raise interesting questions about the plasticity of social signal perception across the species barrier.Electronic supplementary materialThe online version of this article (doi:10.1007/s10071-017-1140-4) contains supplementary material, which is available to authorized users.