Barriers to Care for Pediatric Rural Medulloblastoma Patients Receiving Craniospinal Proton Radiotherapy without In-State Facilities

PURPOSE/OBJECTIVE(S)

Medulloblastoma represents ∼20% of all pediatric brain malignancies. The preferred treatment modality for craniospinal irradiation (CSI) has evolved to be proton beam therapy to reduce late toxicities including secondary malignancy. Access to proton therapy centers is more limited in states without one. Barriers to access for rural patients are underreported in the literature.

MATERIALS/METHODS

Patients <25 years old with a diagnosis of medulloblastoma were identified from a tumor registry at a rural academic center. A chart review was conducted to identify specific barriers to proton beam CSI. Descriptive analyses were performed to describe this cohort and their barriers.

RESULTS

We identified a total of 18 patients diagnosed between 2000 and 2022. The mean age was 10 years old (range 11 months - 20 years). 2 patients were excluded who had minimal documentation. 7 patients were diagnosed before 1/1/2014, a cutoff after which protons were considered more often in this patient population. Patient demographics were 39% female, 61% male, 22% Black, and 72% White, 6% Hispanic. 3 patients received protons. 2 patients had recurrence and 3 patients developed secondary malignancy. Out of 18 patients, proton therapy was discussed with 11 patients. The rates of documented barriers to radiotherapy for the cohort at large (n = 18) and for those where proton therapy was discussed in particular (n = 11) are as follows (cohort at large / had discussion): 4(22%) / 4(36%) difficulty obtaining insurance approval, 4(22%) / 4(36%) inpatient medical needs, 5(28%) / 5(46%) outpatient medical needs, 4(22%) / 4(36%) family scheduling conflicts, 3(17%) / 3(27%) travel costs/financial burdens, 4(22%) / 4(36%) not a clinical trial candidate, 3(17%) / 3(27%) radiotherapy delay, 9(50%) / 5(46%) other barriers to non-radiotherapy care. For the cohort at large or for those with proton therapy discussions, there were no significant associations between white and underrepresented minorities for the aforementioned barriers to care.

CONCLUSION

To our knowledge, this is the first study that identifies patient barriers to accessing proton beam CSI for medulloblastoma patients from a rural tertiary care center without in-state proton radiotherapy centers. This study yields insight into the particular barriers encountered by these patients and their families, allowing clinical teams to identify potential issues in an effort to overcome those barriers. Advocacy for access to care on behalf of this vulnerable patient population may be required by our field on a state and national level.

Rural Pediatric Radiation Oncology in the Era of COVID-19: A Single Institution Analysis

PURPOSE/OBJECTIVE(S)

Health inequities have recently gained prominence in public consciousness as a result of the COVID-19 pandemic. Rural access to care was particularly impacted regarding delays in cancer screening, diagnosis, and treatment. The fractionated nature of radiotherapy creates transportation burdens in this population. We reviewed our institutional experience with pediatric radiotherapy at a tertiary academic center serving a primarily rural population over a large geographic area.

MATERIALS/METHODS

The financial burden of radiotherapy in pediatric patients in our database was modeled using cost-analysis. The cost of transportation using distance to our facility and the IRS-assessed tax value per mile was calculated. Correlative analyses were conducted to evaluate the association of radiotherapy delivered pre- vs. post-COVID with patient race, age at diagnosis, and distance from our institution. Analyses were conducted with two-tailed Pearson correlations for transportation cost vs. age at diagnosis. Mann-Whitney U testing was used to analyze transportation cost vs. patient race. Fisher's Exact Test was used to analyze the trends between tumor primary sites pre- and post-COVID.

RESULTS

There was a statistically significant increase in brain tumors vs. all others from 9.1% to 66.7% post-COVID (p = 0.029). When comparing patients treated prior to the onset of the COVID-19 pandemic in 2020 to those treated during the peak years of the pandemic in 2020-2021, there was no difference in the average distance traveled for treatment. However, the mean cost of transportation for pediatric patients undergoing radiotherapy prior to COVID-19 was $266 USD (median = $331), vs. a mean of $535 (median = $378) for patients treated during 2020-2021. For patients treated in 2022, after the height of COVID-19, the mean cost of transportation was $501 (median = $432). No statistically significant differences were found between the cost of transportation and patient race or age at diagnosis before vs. after the onset of COVID-19.

CONCLUSION

Our results highlight the importance of understanding barriers to care and what type of resources are most impactful to rural pediatric patients at our center. The rise of transportation costs for radiotherapy following the COVID-19 pandemic may indicate an additional barrier to care, potentially associated with increasing inflation, for rural pediatric patients that is underreported in the literature. The rise in the relative prevalence of brain tumors at our institution during this period warrants further investigation.

A SEER Database Cohort of 547 Patients with Non-Squamous Cell Carcinoma of the Penis: Clinical Characteristics and Outcomes

PURPOSE/OBJECTIVE(S)

Little research has investigated the prevalence and distribution of the diverse pathologies of non-squamous cell carcinoma (non-SCC) of the penis. Although rare in clinical practice, these cancers have become a focus of greater importance among patients, clinicians, and researchers, particularly in developing countries. The principal objective of this study was to analyze the major types of penile non-squamous cell carcinoma, elucidate common treatment pathways, and highlight outcomes including 5-year survival.

MATERIALS/METHODS

The Surveillance, Epidemiology and End Results (SEER) database was queried between 2000 to 2018 to identify a retrospective cohort of patients with penile non-SCC. Demographic information, cancer characteristics, diagnostic methods, treatments administered, and survival were investigated.

RESULTS

A total of 547 cases of penile non-SCC were included in the analysis. The most prevalent non-SCC cancers included epithelial neoplasms, not otherwise specified (15.4%), unspecified neoplasms (15.2%), basal cell neoplasms (13.9%), blood vessel tumors (13.0%), nevi and melanomas (11.7%), and ductal and lobular neoplasms (9.9%). Data for the nine most prevalent neoplasms are included in Table 1. Over half (56.7%) of patients elected to undergo surgical intervention. Patients rarely received systemic therapy (3.8%) or radiation (4.0%). Five-year survival was 35.5%. Median survival was 5.2 years (62.7 months). Patients who underwent surgery had greater annual survival for 0 to 10 years compared to those who did not have surgery. Significant differences in survival were found between patients who had regional, localized, and distant metastases (p<0.05). A significant difference in survival was found for patients married at diagnosis versus those who were unmarried at diagnosis (p<0.05). Lower survival rates were observed for patients older than 70 years.

CONCLUSION

Although less prevalent than squamous cell carcinoma, penile non-SCC encompasses a diverse set of neoplasms. Patients in this cohort had a high utilization of surgical management leading to superior outcomes compared to those not receiving surgery. Radiation is an uncommonly pursued treatment pathway. Patient demographics and socioeconomic variables such as marital status may be valuable when investigating cancer outcomes. This updated database analysis can help inform diagnosis, management, and clinical outcomes for this rare group of malignancies.

Use of multiplate electrode aggregometry for personalisonalisation of antiplatelet therapy in left ventricular assisst device patients

Funding Acknowledgements

Type of funding sources: None.

Background

The use of Left Ventricular Assist Devices (LVAD) has noticeably improved the survival for patients with advanced heart failure.  However, this treatment is associated with significant adverse effects. Personalisation of antiplatelet therapy is a key in control and reduction of bleeding/thromboembolic complications of this treatment. However, ISHLT and the manufacturer still recommend unified treatment of 150 mg of acetylsalicylic acid for all LVAD patients. In our centre, we base the treatment decision on clinical picture and patient’s responsiveness to antiplatelet therapy. 

The treatment of choice is acetylsalicylic acid in doses 37.5 mg (1 patient), 75 mg (25 patients) and 150 mg (33 patients). For patients unresponsive or intolerant to acetylsalicylic acid we use 75 mg of clopidogrel, currently 9 patients.  1 patient receives both, 75 mg clopidogrel and 75 mg acetylsalicylic acid. 

Purpose

To gain a better understanding of the platelets function and patients" responses to antiplatelet therapy. In aim to reduce the prevalence of bleeding/thromboembolic related adverse events in LVAD patients, and therefore improve patients outcome.

Methods

In 2020, we decided to introduce a structured/test-based approach to antiplatelet therapy in this patients group. With the use of Multiplate Electrode Aggregometry (MEA) we have attempted to diagnose platelet disorders and monitor effectiveness of antiplatelet therapy. Based on MEA platlets inhibition test we were able to tailor the therapy. 

The retrospective audit was conducted with inclusion criteria;

1. Thromboembolic events include pump thrombosis and any other ischemic complications. Bleeding events contains gastrointestinal (GI) and central nervous system (CNS) events.

2. Any thromboembolic and bleeding events after starting antiplatelet therapy, in the first year after LVAD implantation

Results

The tables below presents reduction in both thromboembolic and bleeding complications.

Conclusion

Presented data can be interpreted that, the test-based approach to antiplatelet therapy may be beneficial in limiting the adverse effects of LVAD therapy. However, it needs to be acknowledged that the observation was carried out on a small group of the patients, over a short period of time. Therefore, an extended period of observation is recommended to obtain further data.

Rumen function and grazing behavior of early-lactation dairy cows supplemented with fodder beet

Fodder beet (FB) is a source of readily fermentable carbohydrate that can mitigate early spring herbage deficits and correct the negative energy balance experienced during early lactation in pastoral dairy systems of New Zealand. However, the low-fiber and high-soluble carbohydrate content of both FB bulb and spring herbage are factors that promote subacute ruminal acidosis, impairing rumen function and limiting the marginal milk production response to supplement. In a crossover experiment, 8 Holstein Friesian × Jersey early-lactation dairy cows were used to test the effect of supplementing 16 kg of dry matter (DM) of a grazed perennial ryegrass herbage with 6 kg of DM/d of FB bulb (FBH) versus herbage only (HO) on changes in rumen function and grazing behavior. Following 20 d of adaptation to diets, DM disappearance (%) of FB bulb (FBH cows only) and herbage were measured in sacco, separately. Cows were fasted overnight, and the ruminal contents were bailed the following morning (~0930 h) again to determine the pool size of volatile fatty acids, ammonia, and particle size of digesta, as well as to estimate the rate of ruminal outflow and degradation of neutral detergent fiber. The FBH diet did not alter DM intake, milk yield, or milk solid (fat + protein) production compared with HO. Supplementation of herbage with FB reduced ruminal pH compared with HO between ~0800 h and 1300 h each day. During each period, 1 cow experienced severe subacute ruminal acidosis (pH <5.6 for >180 min/d) during final adaptation to the target FB allocation. The FBH diet reduced the ruminal pool of acetate and ammonia, but increased the ruminal pool of butyrate and lactate compared with HO. When fed FB, rumination and grazing time increased and grazing intensity declined compared with cows fed HO. Despite increased rumination, the comminution of large particles declined 28% between the first and second rumen bailing when cows were fed FB, and in sacco DM disappearance of perennial ryegrass declined 18% compared with cows fed HO. These results indicate that grazing dairy cows supplemented with FB (40% of daily intake) increase rumination and mastication intensity to counteract reduced ruminal degradation of ryegrass herbage due to low ruminal fluid pH.

Supplementation of Spring Pasture with Harvested Fodder Beet Bulb Alters Rumen Fermentation and Increases Risk of Subacute Ruminal Acidosis during Early Lactation

Simple Summary

Fodder beet (FB) is widely used in grazing dairy systems of New Zealand to support early- and late-lactation milk production, however, the large fraction of water-soluble carbohydrate present in FB bulbs presents a risk of subacute and acute ruminal acidosis. Despite widespread use of FB across New Zealand, the incidence of ruminal acidosis using industry-recommended methods of feeding FB has not been investigated. This study analyzed the time-dependent changes to rumen fermentation, apparent dry matter intake, milk production, milk composition and plasma amino acid concentration of grazing dairy cows supplemented with moderate amounts (40% of dry matter intake) of FB during early lactation. Our findings indicate that incidence of subacute ruminal acidosis due to FB is greater than currently realized, as 25% of cows developed severe subacute ruminal acidosis following transition to target FB allocation (40% of daily intake). Across all cows, FB reduced rumen pH, feed conversion efficiency and was not advantageous to milk production. These results suggest methods for adapting cows to a diet containing FB require further evaluation to reduce the risk of subacute ruminal acidosis (SARA) experienced by individuals within the herd.

Abstract

In a cross-over design, eight rumen cannulated dairy cows were used to explore the industry-recommended method for dietary transition to fodder beet (FB: Beta vulgaris L.) on changes to rumen fermentation and pH, milk production, dry matter intake (DMI) and the risk of subacute ruminal acidosis (SARA) during early lactation. Cows were split into two groups and individually allocated a ryegrass (Lolium Perenne L.) and white clover (Trifolium repens L.) diet (HO) or the same herbage supplemented with 6 kg DM/cow of harvested fodder beet bulbs (FBH). Dietary adaptation occurred over 20 days consisting of: stage 1: gradual transition to target FB intake (days 1–12, +0.5 kg DM of FB/d); stage 2: acclimatization (days 13–17) and stage 3: post-adaption sampling (days 18–20). Response variables were analyzed as a factorial arrangement of diet and stage of adaption using a combination of ANOVA and generalized linear mixed modelling. Dietary proportion of FB represented 22, (stage 1), 32 (stage 2) and 38% (stage 3) of daily DMI. One cow during each period developed SARA from FB and the duration of low pH increased with FBH compared to the HO treatment (p < 0.01). Rumen concentrations of lactic and butyric acid increased with FBH but concentrations of acetate, propionate and total volatile fatty acids (VFA) declined by 9.3% at day 20, compared to the HO treatment (p < 0.01). Treatments did not affect milk production but total DMI with supplemented cows increased during the final stage of adaptation and feed conversion efficiency (FCE kg milk/kg DM) declined with the FBH treatment. The occurrence of SARA in 25% of animals fed FB suggest it is a high-risk supplement to animal health and further evaluation of industry-recommended methods for feeding FB at the individual- and herd-scale are needed.

Predation by introduced cats Felis catus on Australian frogs: compilation of species records and estimation of numbers killed

Abstract ContextWe recently estimated the numbers of reptiles, birds and mammals killed by cats (Felis catus) in Australia, with these assessments providing further evidence that cats have significant impacts on Australian wildlife. No previous studies have estimated the numbers of frogs killed by cats in Australia and there is limited comparable information from elsewhere in the world. AimsWe sought to (1) estimate the numbers of frogs killed by cats in Australia and (2) compile a list of Australian frog species known to be killed by cats. MethodsFor feral cats, we estimated the number of frogs killed from information on their frequency of occurrence in 53 cat dietary studies (that examined stomach contents), the mean number of frogs in dietary samples that contained frogs, and the numbers of cats in Australia. We collated comparable information for take of frogs by pet cats, but the information base was far sparser. Key resultsFrogs were far more likely to be reported in studies that sampled cat stomachs than cat scats. The mean frequency of occurrence of frogs in cat stomachs was 1.5%. The estimated annual per capita consumption by feral cats in Australia’s natural environments is 44 frogs, and, hence, the annual total take is estimated at 92 million frogs. The estimated annual per capita consumption by pet cats is 0.26 frogs, for a total annual kill of one million frogs by pet cats. Thirty native frog species (13% of the Australian frog fauna) are known to be killed by cats: this tally does not include any of the 51 threatened frog species, but this may simply be because no cat dietary studies have occurred within the small ranges typical of threatened frog species. ConclusionsThe present study indicated that cats in Australia kill nearly 100 million frogs annually, but further research is required to understand the conservation significance of such predation rates. ImplicationsThe present study completed a set of reviews of the impacts of cats on Australian terrestrial vertebrates. Cat predation on Australian frogs is substantial, but is likely to be markedly less than that on Australian reptiles, birds and mammals.

Methane and carbon dioxide emissions from lactating dairy cows grazing mature ryegrass/white clover or a diverse pasture comprising ryegrass, legumes and herbs

There is a growing interest in forage mixtures (Diverse pasture; e.g. containing grasses, legumes and herbs), especially those with a greater tolerance of dry conditions and a decreased nitrogen (N) content (reducing N losses), compared with ryegrass (Lolium perenne L and Lolium multiflorum L)/white clover (Trifolium repens L) pastures (RyeWC), which dominate New Zealand pastoral systems for dairy production. However, the effect of alternative forages on enteric methane (CH4) emissions is not known. The objective of the present trial was to compare CH4 emissions and milk production from dairy cows grazing either mature RyeWC or mature Diverse pasture (both approximately with pasture mass of 5600 kg DM/ha). The Diverse mixture comprised ryegrass, white clover, lucerne (Medicago sativa L), chicory (Cichorium intybus L) and plantain (Plantago lanceolata L). Milk production, measured from cows commencing at ~162 days of lactation, was less when cows grazed RyeWC than Diverse pastures (15.4 vs 16.7 kg/day; P &lt; 0.001), whereas CH4 production (g/day) was similar for the respective treatments (411 g/day; P = 0.16). Milk composition was not affected by diet and CH4 intensity was similar for both diets (22 g/kg fat- and protein-corrected milk; P = 0.31). Methane yield [g/kg predicted dry matter intake (DMI)] averaged 22.6 and 24.9 for cows grazing RyeWC and Diverse pastures, respectively (P = 0.006). In conclusion, although the CH4 yield was greater when Diverse pasture was grazed, relative to RyeWC, there were no differences in emissions intensity or total CH4 emissions.

In vitro degradation of a unique porous PHBV scaffold manufactured using selective laser sintering

Biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffolds have shown great promise for bone tissue engineering applications. The investigation of their hydrolytic degradation is thus essential to understand the effect of hydrolysis on the complex biodegradation behavior of PHBV scaffolds. In this study, we investigated the degradation behavior of high molecular weight PHBV scaffolds manufactured using selective laser sintering (SLS) without using predesigned porous architectures. The manufactured scaffolds have high specific surface areas with great water-uptake abilities. After an incubation of 6 weeks in phosphate-buffered saline solution, the structural integrity of the scaffolds was unaffected. However, a significant decrease in molecular weight ranging from 39% to 46% was found. The measured weight loss was negligible, but their compressive modulus and strength both decreased, likely due to water plasticization. These findings suggest that hydrolytic degradation of PHBV by means of bulk degradation was the predominant mechanism, attributed to their excellent water absorptivity. Overall, the PHBV scaffolds manufactured using SLS exhibited adequate mechanical properties and satisfactory structural integrity after incubation. As a result, the scaffolds have great potential as candidates for bone repair in clinical practice. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 154-162, 2019.

How many reptiles are killed by cats in Australia?

Context Feral cats (Felis catus) are a threat to biodiversity globally, but their impacts upon continental reptile faunas have been poorly resolved. Aims To estimate the number of reptiles killed annually in Australia by cats and to list Australian reptile species known to be killed by cats. Methods We used (1) data from >80 Australian studies of cat diet (collectively >10 000 samples), and (2) estimates of the feral cat population size, to model and map the number of reptiles killed by feral cats. Key results Feral cats in Australia’s natural environments kill 466 million reptiles yr–1 (95% CI; 271–1006 million). The tally varies substantially among years, depending on changes in the cat population driven by rainfall in inland Australia. The number of reptiles killed by cats is highest in arid regions. On average, feral cats kill 61 reptiles km–2 year–1, and an individual feral cat kills 225 reptiles year–1. The take of reptiles per cat is higher than reported for other continents. Reptiles occur at a higher incidence in cat diet than in the diet of Australia’s other main introduced predator, the European red fox (Vulpes vulpes). Based on a smaller sample size, we estimate 130 million reptiles year–1 are killed by feral cats in highly modified landscapes, and 53 million reptiles year–1 by pet cats, summing to 649 million reptiles year–1 killed by all cats. Predation by cats is reported for 258 Australian reptile species (about one-quarter of described species), including 11 threatened species. Conclusions Cat predation exerts a considerable ongoing toll on Australian reptiles. However, it remains challenging to interpret the impact of this predation in terms of population viability or conservation concern for Australian reptiles, because population size is unknown for most Australian reptile species, mortality rates due to cats will vary across reptile species and because there is likely to be marked variation among reptile species in their capability to sustain any particular predation rate. Implications This study provides a well grounded estimate of the numbers of reptiles killed by cats, but intensive studies of individual reptile species are required to contextualise the conservation consequences of such predation.

Atomic resolution of structural changes in elastic crystals of copper(II) acetylacetonate

Single crystals are typically brittle, inelastic materials. Such mechanical responses limit their use in practical applications, particularly in flexible electronics and optical devices. Here we describe single crystals of a well-known coordination compound-copper(II) acetylacetonate-that are flexible enough to be reversibly tied into a knot. Mechanical measurements indicate that the crystals exhibit an elasticity similar to that of soft materials such as nylon, and thus display properties normally associated with both hard and soft matter. Using microfocused synchrotron radiation, we mapped the changes in crystal structure that occur on bending, and determined the mechanism that allows this flexibility with atomic precision. We show that, under strain, the molecules in the crystal reversibly rotate, and thus reorganize to allow the mechanical compression and expansion required for elasticity and still maintain the integrity of the crystal structure.

Feeding diets with fodder beet decreased methane emissions from dry and lactating dairy cows in grazing systems

Fodder beet (Beta vulgaris L.) has a very high readily fermentable carbohydrate concentration, which could affect rumen fermentation and reduce enteric methane (CH4) emissions. The objective of the current study was to estimate CH4 emissions from dry dairy cows grazing either fodder beet supplemented with perennial ryegrass (Lolium perenne L.)-dominated pasture silage (6 kg DM/cow/day; FB+Sil) or forage kale (Brassica oleracea L.) supplemented with barley (Hordeum vulgare L.) straw (3 kg DM/cow/day; kale+Str; dry cows, Experiment 1), and from dairy cows in early lactation grazing perennial ryegrass-dominated pasture alone (pasture) or supplemented with fodder beet bulbs (3 kg DM/cow/day; past+FB; lactating cows; Experiment 2). Methane measurements were performed using GreenFeed units (C-Lock Inc., Rapid City, SD, USA) for 40 days in August–September 2015 (Experiment 1) and for 22 days in November–December 2015 (Experiment 2), from 45 and 31 Holstein–Friesian × Jersey dairy cows in Experiments 1 and 2, respectively. Dry cows grazing FB+Sil in Experiment 1 produced 18% less CH4 (g/day) and had 28% lower CH4 yield (g/kg DM intake; P < 0.001) than did cows grazing kale+Str. Lactating cows grazing past+FB in Experiment 2 produced 18% less CH4 and had 16% lower CH4 intensity (g/kg fat and protein-corrected milk production; P < 0.01) than did cows grazing pasture alone, while milk production and composition were similar for the two groups. In conclusion, feeding fodder beet at ~50% and 20% of the diet of dry and lactating dairy cows in pastoral systems can mitigate CH4 emissions.

Herbage dry-matter yield and nitrogen concentration of grass, legume and herb species grown at different nitrogen-fertiliser rates under irrigation

An important goal in dairy systems is to increase production while achieving environmental targets associated with lower nitrate leaching from soils. One approach is to identify forages that grow more at a given level of nitrogen (N) input and result in a lower N intake per kilogram dry matter (DM) consumed. However, while N responses have been well described for perennial ryegrasses, less information is available for alternative grasses, legumes and herbs. In the present study, conducted on the Canterbury Plains, New Zealand, six species (perennial ryegrass, Italian ryegrass, white clover, lucerne, chicory and plantain) were grown at six N-fertiliser rates ranging from 0 to 450 kg N/ha.year and managed under irrigation and cutting management. Herbage DM yield and N concentration were measured over 12 months. As N-fertiliser rate increased from 0 to 450 kg N/ha, annual herbage yield increased linearly (from 4794 to 14 329 kg DM/ha.year in grasses and from 7146 to 13 177 kg DM/ha.year in herbs). In contrast, annual herbage yield for legumes was unaffected by N-fertiliser rate and ranged from 11 874 to 13 112 kg DM/ha. Additionally, there were contrasting responses in herbage N concentration between species. At all N-fertiliser rates, herbage N concentration was highest in legumes (43.4 g N/kg DM), then herbs (30.7 g N/kg DM), and lowest in grasses (25.8 g N/kg DM). The N concentration of legume DM was unaffected by increasing N-fertiliser rate, whereas in grasses and herbs it increased. Results suggested that there were no benefits in using herbs instead of grasses for reducing N intake in livestock in an irrigated Canterbury environment.

Characterising the material properties at the interface between skin and a skin vaccination microprojection device

The rapid emergence of micro-devices for biomedical applications over the past two decades has introduced new challenges for the materials used in the devices. Devices like microneedles and the Nanopatch, require sufficient strength to puncture skin often with sharp-slender micro-scale profiles, while maintaining mechanical integrity. For these technologies we sought to address two important questions: 1) On the scale at which the device operates, what forces are required to puncture the skin? And 2) What loads can the projections/microneedles withstand prior to failure. First, we used custom fabricated nanoindentation micro-probes to puncture skin at the micrometre scale, and show that puncture forces are ∼0.25-1.75mN for fresh mouse skin, in agreement with finite element simulations for our device. Then, we used two methods to perform strength tests of Nanopatch projections with varied aspect ratios. The first method used a nanoindenter to apply a force directly on the top or on the side of individual silicon projections (110μm in length, 10μm base radius), to measure the force of fracture. Our second method used an Instron to fracture full rows of projections and characterise a range of projection designs (with the method verified against previous nanoindentation experiments). Finally, we used Cryo-Scanning Electron Microscopy to visualise projections in situ in the skin to confirm the behaviour we quantified, qualitatively.

STATEMENT OF SIGNIFICANCE

Micro-device development has proliferated in the past decade, including devices that interact with tissues for biomedical outcomes. The field of microneedles for vaccine delivery to skin has opened new material challenges both in understanding tissue material properties and device material. In this work we characterise both the biomaterial properties of skin and the material properties of our microprojection vaccine delivery device. This study directly measures the micro-scale puncture properties of skin, whilst demonstrating clearly how these relate to device design. This will be of strong interest to those in the field of biomedical microdevices. This includes work in the field of wearable and semi-implantable devices, which will require clear understanding of tissue behaviour and material characterisation.

The effect of feeding maize silage 1 h or 9 h before the herbage meal on dry matter intake, milk production, nitrogen partitioning and rumen function of lactating dairy cows

The study was conducted to evaluate the effect of the timing of feeding maize silage before a short herbage meal on dry matter (DM) intake, milk production, nitrogen (N) partitioning and rumen function of lactating dairy cows. Ten lactating, pregnant, Friesian × Jersey rumen-fistulated dairy cows aged 4–5 years were blocked in pairs by milksolids (MS; sum of protein and fat) production (1.73 ± 0.097 kg MS/cow.day; mean ± s.d.), bodyweight (519 ± 24.7 kg), days in milk (163 ± 12.5), and body condition score (3.9 ± 0.21). Cows within pairs were randomly allocated to one of two treatments: (1) five cows were offered one-third of their estimated total DM intake (5 kg/cow.day) as maize silage after the afternoon milking at 1500 hours, ~1 h before herbage was provided (1BH); (2) five cows were offered one-third of their estimated total DM intake as maize silage after morning milking at 0700 hours, ~9 h before herbage was provided (9BH). All cows were offered two-thirds of their total estimated DM intake (11 kg/cow.day) over a period of 4 h from 1600 hours to 2000 hours as freshly cut perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens) in an indoor system. Cows were adapted to diets for 9 days (Days 1–9), followed by 5 days of measurement (Days 10–14). Maize silage DM intake did not differ between treatments averaging 5.1 kg DM/cow.day. Herbage DM intake was greater (P = 0.02) for 9BH (11.2 kg DM/cow.day) than 1BH (10.4 kg DM/cow.day). Milk yield (P = 0.001) and MS production (P = 0.08) were greater for 9BH than 1BH (18.8 vs 15.4 kg/cow.day and 1.63 vs 1.48 kg MS/cow.day, respectively). There was no effect of time of supplementation on N partitioned to milk, faeces, or urine. The purine derivatives to creatinine ratio, as an indication of microbial protein production, was greater (P = 0.04) for 9BH than 1BH. Daily mean rumen pH and the concentration of total rumen volatile fatty acids, acetate, butyrate, and ammonia N were not affected by treatment. However, the peak concentration of ruminal ammonia N was 27% lower (P < 0.05) for 9BH than 1BH. The concentration of non-esterified fatty acid (P = 0.03) and beta-hydroxy butyric acid (P = 0.01) were greater for 1BH than 9BH (0.14 vs 0.09 and 0.81 vs 0.71 mmol/L, respectively). These results indicate that under herbage feed restriction, altering the time of supplementation relative to the herbage meal can increase herbage DM intake and subsequent milk production.

The experiences of participating in winter among youths with a physical disability compared with their typically developing peers

BACKGROUND

Having a physical disability and using a wheelchair can create difficulties in navigating the physical and built environment, especially during winter when snow and ice become problematic. Little is known about the experiences of winter among youth who use an assistive mobility device. This study aimed to understand how youth with a physical disability experience winter, compared with typically developing peers.

METHODS

A purposive sample of 25 youths (13 with a physical disability; 12 typically developing) completed a 2-week weather journal and photographs in two Canadian cities during winter. These data were used to guide semi-structured interviews with participants.

RESULTS

Youths with disabilities experienced many similar challenges in winter, such as health and safety concerns and accessibility issues, compared with typically developing youth - but to a greater extent. Youths with disabilities reported more challenges going outdoors during winter and negative psychosocial impacts, including loneliness and increased dependence, compared with peers without a disability. They also, however, described developing several adaptive strategies to cope with these challenges.

CONCLUSIONS

There is a strong need to remove physical and environmental barriers to facilitate the participation and inclusion of youth with disabilities in winter.

Efficient national surveillance for health-care-associated infections

Background

Detecting novel healthcare-associated infections (HCAI) as early as possible is an important public health priority. However, there is currently no evidence base to guide the design of efficient and reliable surveillance systems. Here we address this issue in the context of a novel pathogen spreading primarily between hospitals through the movement of patients.

Methods

Using a mathematical modelling approach we compare the current surveillance system for a HCAI that spreads primarily between hospitals due to patient movements as it is implemented in Scotland with a gold standard to determine if the current system is maximally efficient or whether it would be beneficial to alter the number and choice of hospitals in which to concentrate surveillance effort.

Results

We validated our model by demonstrating that it accurately predicts the risk of meticillin-resistant Staphylococcus aureus bacteraemia cases in Scotland.

Using the 29 (out of 182) sentinel hospitals that currently contribute most of the national surveillance effort results in an average detection time of 117 days. A reduction in detection time to 87 days is possible by optimal selection of 29 hospitals. Alternatively, the same detection time (117 days) can be achieved using just 22 optimally selected hospitals. Increasing the number of sentinel hospitals to 38 (teaching and general hospitals) reduces detection time by 43 days; however decreasing the number to seven sentinel hospitals (teaching hospitals) increases detection time substantially to 268 days.

Conclusions

Our results show that the current surveillance system as it is used in Scotland is not optimal in detecting novel pathogens when compared to a gold standard. However, efficiency gains are possible by better choice of sentinel hospitals, or by increasing the number of hospitals involved in surveillance. Similar studies could be used elsewhere to inform the design and implementation of efficient national, hospital-based surveillance systems that achieve rapid detection of novel HCAIs for minimal effort.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2172-9) contains supplementary material, which is available to authorized users.

Staphylococcus aureus and the oral cavity: an overlooked source of carriage and infection?

BACKGROUND

The role of intraoral Staphylococcus aureus in disease and cross-infection sources is controversial. We present a 10-year retrospective analysis of laboratory data reporting isolation of S aureus from oral and perioral clinical specimens.

METHODS

A review of laboratory records for specimens where S aureus was isolated were collated and analyzed from January 1998-December 2007 at the Oral Microbiology Laboratory, Glasgow Dental Hospital.

RESULTS

There were 11,312 specimens submitted to the laboratory over the study time period. S aureus was isolated from 1,986 specimens (18%). Of these, 1,782 (90%) were methicillin-sensitive S aureus (MSSA), and 204 (10%) were methicillin-resistant S aureus (MRSA). The most common specimen type from which MSSA was isolated was an oral rinse, whereas for MRSA this was a tongue swab. Most of the MRSA isolates were EMRSA-15 or EMRSA-16 lineage.

CONCLUSION

These findings suggest that S aureus continues to be a frequent isolate in the oral cavity and perioral region. The oral cavity should be considered a source of S aureus in terms of cross-infection and dissemination to other body sites. The role of S aureus in the pathogenesis of certain oral diseases should also be considered as part of a differential diagnosis.

Stimulated release of a hyperpolarizing factor (ADHF) from mesenteric artery perivascular adipose tissue: involvement of myocyte BKCa channels and adiponectin

BACKGROUND AND PURPOSE

Perivascular adipose tissue (PVAT) releases adipocyte-derived hyperpolarizing factors (ADHFs) that may partly act by opening myocyte K(+) channels. The present study in rat and mouse mesenteric arteries aimed to identify the myocyte K(+) channel activated by PVAT and to determine whether adiponectin contributed to the hyperpolarizing effects of PVAT.

EXPERIMENTAL APPROACH

Myocyte membrane potential was recorded from de-endothelialized, non-contracted rat and mouse mesenteric arteries in the presence and absence of PVAT.

KEY RESULTS

The β3 -adrenoceptor agonist, CL-316,243 (10 μM), generated PVAT-dependent, iberiotoxin-sensitive myocyte hyperpolarizations resulting from BKCa channel opening and which were partially blocked by L-NMMA (100 μM). Adiponectin (5 μg·mL(-1) ) also produced iberiotoxin-sensitive hyperpolarizations in PVAT-denuded arterioles. Activation of myocyte AMP-activated protein kinase (AMPK) using 5 μM A-769662 also induced BKCa -mediated hyperpolarizations. Dorsomorphin abolished hyperpolarizations to CL-316,243, adiponectin and A-769662. In vessels from Adipo(-/-) mice, hyperpolarizations to CL-316,243 were absent whereas those to A-769662 and adiponectin were normal. In rat vessels, adipocyte-dependent hyperpolarizations were blocked by glibenclamide and clotrimazole but those to NS1619 (33 μM) were unaltered.

CONCLUSIONS AND IMPLICATIONS

Under basal, non-contracted conditions, β3 -adrenoceptor stimulation of PVAT releases an ADHF, which is probably adiponectin. This activates AMPK to open myocyte BKCa channels indirectly and additionally liberates NO, which also contributes to the observed PVAT-dependent myocyte hyperpolarizations. Clotrimazole and glibenclamide each reversed hyperpolarizations to adiponectin and A-769662, suggesting the involvement of myocyte TRPM4 channels in the ADHF-induced myocyte electrical changes mediated via the opening of BKCa channels.

Cluster of Legionnaires’ disease cases caused by Legionella longbeachae serogroup 1, Scotland, August to September 2013

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Genome-wide single nucleotide polymorphism-based assay for high-resolution epidemiological analysis of the methicillin-resistant Staphylococcus aureus hospital clone EMRSA-15

The EMRSA-15 clone is a major cause of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections in the UK and elsewhere but existing typing methodologies have limited capacity to discriminate closely related strains, and are often poorly reproducible between laboratories. Here, we report the design, development and validation of a genome-wide single nucleotide polymorphism (SNP) typing method and compare it to established methods for typing of EMRSA-15. In order to identify discriminatory SNPs, the genomes of 17 EMRSA-15 strains, selected to represent the breadth of genotypic and phenotypic diversity of EMRSA-15 isolates in Scotland, were determined and phylogenetic reconstruction was carried out. In addition to 17 phylogenetically informative SNPs, five binary markers were included to form the basis of an EMRSA-15 genotyping assay. The SNP-based typing assay was as discriminatory as pulsed-field gel electrophoresis, and significantly more discriminatory than staphylococcal protein A (spa) typing for typing of a representative panel of diverse EMRSA-15 strains, isolates from two EMRSA-15 hospital outbreak investigations, and a panel of bacteraemia isolates obtained in healthcare facilities in the east of Scotland during a 12-month period. The assay is a rapid, and reproducible approach for epidemiological analysis of EMRSA-15 clinical isolates in Scotland. Unlike established methods the DNA sequence-based method is ideally suited for inter-laboratory comparison of identified genotypes, and its flexibility lends itself to supplementation with additional SNPs or markers for the identification of novel S. aureus strains in other regions of the world.