Biodistribution of liposomal I-VIP in rat using gamma camera

Vasoactive intestinal peptide (VIP), a 28 amino-acid peptide was labeled with ¹³¹I and encapsulated into liposomes. ¹³¹I-VIP or liposomal ¹³¹I -VIP was administered intravenously into the rats. The distribution was studied by a gamma camera and established by counting the radioactivity in the removed organs. The elimination half-life for the liposomal ¹³¹I-VIP in both blood and lungs was significantly longer (5.29 and 9.28 min, respectively) than that obtained after the administration of ¹³¹I-VIP (0.62 and 3.18 min, respectively). Dynamic scans using a gamma camera after the administration of liposomal ¹³¹I-VIP showed a higher uptake of the liposomal form into the lungs compared with ¹³¹I-VIP. The lack of VIP in asthmatics has been shown in previous studies. However, the clinical investigations using VIP were disappointing most probably due to the rapid degradation of the peptide in the bronchial tract. This in fact is supported by our previous study, in which we demonstrated that VIP had a half-life of 0.45 min in blood. We conclude that the encapsulation of VIP in liposomes prolongs its elimination half-life in plasma and enhances its uptake in lungs. This observation may increase the clinical use of VIP in both diagnostic and therapy.     

A novel phantom design for emission tomography enabling scatter- and attenuation-”free” single-photon emission tomography imaging

A newly designed technique for experimental single-photon emission tomography (SPET) and positron emission tomography (PET) data acquisition with minor disturbing effects from scatter and attenuation has been developed. In principle, the method is based on discrete sampling of the radioactivity distribution in 3D objects by means of equidistant 2D planes. The starting point is a set of digitised 2D sections representing the radioactivity distribution of the 3D object. Having a radioactivity-related grey scale, the 2D images are printed on paper sheets using radioactive ink. The radioactive sheets can be shaped to the outline of the object and stacked into a 3D structure with air or some arbitrary dense material in between. For this work, equidistantly spaced transverse images of a uniform cylindrical phantom and of the digitised Hoffman rCBF phantom were selected and printed out on paper sheets. The uniform radioactivity sheets were imaged on the surface of a low-energy ultra-high-resolution collimator (4 mm full-width at half-maximum) of a three-headed SPET camera. The reproducibility was 0.7% and the uniformity was 1.2%. Each rCBF sheet, containing between 8.3 and 80 MBq of ^99mTcO₄ ^– depending on size, was first imaged on the collimator and then stacked into a 3D structure with constant 12 mm air spacing between the slices. SPET was performed with the sheets perpendicular to the central axis of the camera. The total weight of the stacked rCBF phantom in air was 63 g, giving a scatter contribution comparable to that of a point source in air. The overall attenuation losses were <20%. A second SPET study was performed with 12-mm polystyrene plates in between the radioactive sheets. With polystyrene plates, the total phantom weight was 2300 g, giving a scatter and attenuation magnitude similar to that of a patient study. With the proposed technique, it is possible to obtain ”ideal” experimental images (essentially built up by primary photons) for comparison with ”real” images degraded by photon scattering and attenuation losses. The method can serve as a tool for experimental validation and intercomparison of attenuation and scatter correction methods. Moreover, the large flexibility of this phantom design will allow investigations of arbitrary activity distributions and autoradiography or other imaging techniques such as PET, x-ray computed tomography or magnetic resonance imaging. Received 8 August and in revised form 21 September 1999     

Population cost-effectiveness of the Triple P parenting programme for the treatment of conduct disorder: an economic modelling study

Parenting programmes are the recommended treatments of conduct disorders (CD) in children, but little is known about their longer term cost-effectiveness. This study aimed to evaluate the population cost-effectiveness of one of the most researched evidence-based parenting programmes, the Triple P—Positive Parenting Programme, delivered in a group and individual format, for the treatment of CD in children. A population-based multiple cohort decision analytic model was developed to estimate the cost per disability-adjusted life year (DALY) averted of Triple P compared with a ‘no intervention’ scenario, using a health sector perspective. The model targeted a cohort of 5–9-year-old children with CD in Australia currently seeking treatment, and followed them until they reached adulthood (i.e., 18 years). Multivariate probabilistic and univariate sensitivity analyses were conducted to incorporate uncertainty in the model parameters. Triple P was cost-effective compared to no intervention at a threshold of AU$50,000 per DALY averted when delivered in a group format [incremental cost-effectiveness ratio (ICER) = $1013 per DALY averted; 95% uncertainty interval (UI) 471–1956] and in an individual format (ICER = $20,498 per DALY averted; 95% UI 11,146–39,470). Evidence-based parenting programmes, such as the Triple P, for the treatment of CD among children appear to represent good value for money, when delivered in a group or an individual face-to-face format, with the group format being the most cost-effective option. The current model can be used for economic evaluations of other interventions targeting CD and in other settings.     

Post-fracture Risk Assessment: Target the Centrally Sited Fractures First! A Substudy of NoFRACT

The location of osteoporotic fragility fractures adds crucial information to post-fracture risk estimation. Triaging patients according to fracture site for secondary fracture prevention can therefore be of interest to prioritize patients considering the high imminent fracture risk. The objectives of this cross-sectional study were therefore to explore potential differences between central (vertebral, hip, proximal humerus, pelvis) and peripheral (forearm, ankle, other) fractures. This substudy of the Norwegian Capture the Fracture Initiative (NoFRACT) included 495 women and 119 men ≥50 years with fragility fractures. They had bone mineral density (BMD) of the femoral neck, total hip, and lumbar spine assessed using dual-energy X-ray absorptiometry (DXA), trabecular bone score (TBS) calculated, concomitantly vertebral fracture assessment (VFA) with semiquantitative grading of vertebral fractures (SQ1–SQ3), and a questionnaire concerning risk factors for fractures was answered. Patients with central fractures exhibited lower BMD of the femoral neck (765 versus 827 mg/cm²), total hip (800 versus 876 mg/cm²), and lumbar spine (1024 versus 1062 mg/cm²); lower mean TBS (1.24 versus 1.28); and a higher proportion of SQ1-SQ3 fractures (52.0% versus 27.7%), SQ2–SQ3 fractures (36.8% versus 13.4%), and SQ3 fractures (21.5% versus 2.2%) than patients with peripheral fractures (all p < 0.05). All analyses were adjusted for sex, age, and body mass index (BMI); and the analyses of TBS and SQ1–SQ3 fracture prevalence was additionally adjusted for BMD). In conclusion, patients with central fragility fractures revealed lower femoral neck BMD, lower TBS, and higher prevalence of vertebral fractures on VFA than the patients with peripheral fractures. This suggests that patients with central fragility fractures exhibit more severe deterioration of bone structure, translating into a higher risk of subsequent fragility fractures and therefore they should get the highest priority in secondary fracture prevention, although attention to peripheral fractures should still not be diminished. © 2019 American Society for Bone and Mineral Research. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.     

5-FU resistant EMT-like pancreatic cancer cells are hypersensitive to photochemical internalization of the novel endoglin-targeting immunotoxin CD105-saporin

Background

Development of resistance to 5-fluorouracil (5-FU) is a major problem in treatment of various cancers including pancreatic cancer. In this study, we reveal important resistance mechanisms and photochemical strategies to overcome 5-FU resistance in pancreatic adenocarcinoma.

Methods

5-FU resistant (5-FUR), epithelial-to-mesenchymal-like sub-clones of the wild type pancreatic cancer cell line Panc03.27 were previously generated in our lab. We investigated the cytotoxic effect of the endosomal/lysosomal-localizing photosensitizer TPCS_2a (fimaporfin) combined with light (photochemical treatment, PCT) using MTS viability assay, and used fluorescence microscopy to show localization of TPCS_2a and to investigate the effect of photodamage of lysosomes. Flow cytometric analysis was performed to investigate uptake of photosensitizer and to assess intracellular ROS levels. Expression and localization of LAMP1 was assessed using RT-qPCR, western blotting, and structured illumination microscopy. MTS viability assay was used to assess the effect of combinations of 5-FU, chloroquine (CQ), and photochemical treatment. Expression of CD105 was investigated using RT-qPCR, western blotting, flow cytometry, and fluorescence microscopy, and co-localization of TPCS_2a and anti-CD105-saporin was assessed using microscopy. Lastly, the MTS assay was used to investigate cytotoxic effects of photochemical internalization (PCI) of the anti-CD105-immunotoxin.

Results

The 5-FUR cell lines display hypersensitivity to PCT, which was linked to increased uptake of TPCS_2a, altered lysosomal distribution, lysosomal photodamage and increased expression of the lysosomal marker LAMP-1 in the 5-FUR cells. We show that inhibition of autophagy induced by either chloroquine or lysosomal photodamage increases the sensitivity to 5-FU in the resistant cells. The three 5-FUR sub-clones overexpress Endoglin (CD105). Treatment with the immunotoxin anti-CD105-saporin alone significantly reduced the viability of the CD105-expressing 5-FUR cells, whereas little effect was seen in the CD105-negative non-resistant parental cancer cell lines. Strikingly, using the intracellular drug delivery method photochemical internalization (PCI) by combining light-controlled activation of the TPCS_2a with nanomolar levels of CD105-saporin resulted in strong cytotoxic effects in the 5-FUR cell population.

Conclusion

Our findings suggested that autophagy is an important resistance mechanism against the chemotherapeutic drug 5-FU in pancreatic cancer cells, and that inhibition of the autophagy process, either by CQ or lysosomal photodamage, can contribute to increased sensitivity to 5-FU. For the first time, we demonstrate the promise of PCI-based targeting of CD105 in site-specific elimination of 5-FU resistant pancreatic cancer cells in vitro. In conclusion, PCI-based targeting of CD105 may represent a potent anticancer strategy and should be further evaluated in pre-clinical models.

     

Pharmacokinetics and pharmacodynamics of AZD6244 (ARRY-142886) in tumor-bearing nude mice

Purpose

AZD6244 (ARRY-142886) (AstraZeneca, Macclesfield, UK) is a novel small molecule MEK1/2 inhibitor that is currently being tested in Phase II trials. With the recent publication of human pharmacokinetic data from clinical studies, we now know the achievable levels and range of AZD6244 exposure in humans. This study aimed to describe the pharmacokinetic profile of AZD6244 in mice in order to design preclinical studies that recapitulate exposure levels in humans.

Methods

Male athymic, nude mice received subcutaneous inoculation of A375 human melanoma cells. Once tumors reached 400?C700?mm³, mice were given a single dose of either 5 or 10?mg/kg AZD6244 via oral gavage. Additionally, a subset of mice was dosed once daily for 1?week (10?mg/kg). Mice were killed and plasma and tissues were collected at various time points after the last dose. Samples were analyzed by LC/MS/MS for AZD6244 concentration. Additionally, pharmacodynamic endpoints such as tumor proliferation and ERK phosphorylation were analyzed at various time points after the last dose.

Results

After either a single dose or at steady state, at clinically equivalent exposures, AZD6244 effectively inhibits ERK phosphorylation and suppresses proliferation. Furthermore, we describe a hysteretic relationship between the pharmacokinetics and the pharmacodynamics of AZD6244 and both target and pharmacologic responses.

Conclusions

The information presented herein will drive the rational design of pre-clinical studies that are not only relevant to the clinical setting, but also pave the way to understand the biological response to AZD6244 treatment.     

"Coming ready or not" high fidelity human patient simulation in child and adolescent psychiatric nursing education: diffusion of Innovation

This paper is the first to address high fidelity human patient simulation (HFHPS) as a technique to prepare pre-registration nursing students for practice in child and adolescent psychiatric nursing (CAPN). By examining the published literature in a systematic review, no evidence was located that discussed the application of this innovative mannequin-based educational technique for this population. Indeed, mental health nursing preparation generally had minimal literature addressing the adoption of HFHPS.Rogers' (2003) model of the “Diffusion of Innovation” was applied as a lens to explain this observation. His model fitted this observed pattern well and provided a range of explanatory paradigms. It was limited, however, in its predictive ability to suggest when and under what conditions HFHPS might be expected to be adopted by nursing preparation programmes for CAPN.At the conclusion to this examination, the absence of a conversation evident in the mental health or CAPN literature on the preparation of pre-registration nursing students using this educational technique is striking. The potential of this approach to be combined in new ways to better prepare nursing students for the challenges of practice in mental health or CAPN needs extensive examination.     

Patient care encounters with the MCHL: a questionnaire study

BACKGROUND: Both internationally and nationally, the medical care help line (MCHL) is a growing operation within the healthcare field. In Sweden, approximately 5 million calls per year are processed. The service is managed by specially trained nurses. Aim: To describe how patients' sex, age, education level and care level influenced their perceptions of care encounters with the MCHL. METHODOLOGICAL DESIGN AND INSTRUMENT: A questionnaire was designed through the operationalisation of terms based on a previous interview study with MCHL callers. It was distributed to 858 callers in a region of southwest Sweden. The questionnaire was comprised of 14 visual analogue scales (VAS). Validity and reliability were determined to be acceptable by a pilot study and factor analyses. RESULTS: Response frequency n = 517 (60.4 %). Three factors, interaction, service and product, emerged to describe high satisfaction with the MCHL from different perspectives. The items 'friendliness', 'respect', 'confirmation', 'accessibility' and 'simplicity' scored highest, whereas the 'joint decision-making', 'composure' and 'time' items had the lowest values. CONCLUSIONS AND RELEVANCE TO CLINICAL NURSING: A new questionnaire with acceptable validity and reliability was created on the basis of an interview study examining patient encounters with the MCHL. The new questionnaire may provide useful support in the education of MCHL nurses and other nurses in telephone triage. It can also be used for quality development and as a basis for further research on telephone nursing.