User testing of a diagnostic decision support system with machine-assisted chart review to facilitate clinical genomic diagnosis

Objectives

There is a need in clinical genomics for systems that assist in clinical diagnosis, analysis of genomic information and periodic reanalysis of results, and can use information from the electronic health record to do so. Such systems should be built using the concepts of human-centred design, fit within clinical workflows and provide solutions to priority problems.

Methods

We adapted a commercially available diagnostic decision support system (DDSS) to use extracted findings from a patient record and combine them with genomic variant information in the DDSS interface. Three representative patient cases were created in a simulated clinical environment for user testing. A semistructured interview guide was created to illuminate factors relevant to human factors in CDS design and organisational implementation.

Results

Six individuals completed the user testing process. Tester responses were positive and noted good fit with real-world clinical genetics workflow. Technical issues related to interface, interaction and design were minor and fixable. Testers suggested solving issues related to terminology and usability through training and infobuttons. Time savings was estimated at 30%–50% and additional uses such as in-house clinical variant analysis were suggested for increase fit with workflow and to further address priority problems.

Conclusion

This study provides preliminary evidence for usability, workflow fit, acceptability and implementation potential of a modified DDSS that includes machine-assisted chart review. Continued development and testing using principles from human-centred design and implementation science are necessary to improve technical functionality and acceptability for multiple stakeholders and organisational implementation potential to improve the genomic diagnosis process.

Room temperature laser power standard using a microfabricated, electrical substitution bolometer

The design and performance of a room temperature electrical substitution radiometer for use as an absolute standard for measuring continuous-wave laser power over a wide range of wavelengths, beam diameters, and powers are described. The standard achieves an accuracy of 0.46% (k = 2) for powers from 10 mW to 100 mW and 0.83% (k = 2) for powers from 1 mW to 10 mW and can accommodate laser beam diameters (1/e²) up to 11 mm and wavelengths from 300 nm to 2 μm. At low power levels, the uncertainty is dominated by sensitivity to fluctuations in the thermal environment. The core of the instrument is a planar, silicon microfabricated bolometer with vertically aligned carbon nanotube absorbers, commercial surface mount thermistors, and an integrated heater. Where possible, commercial electronics and components were used. The performance was validated by comparing it to a National Institute of Standards and Technology primary standard through a transfer standard silicon trap detector and by comparing it to the legacy "C-series" standards in operation at the U.S. Air Force Metrology and Calibration Division (AFMETCAL).

P591Insights from Exercise Cardiac Magnetic Resonance Imaging (ExMR) With Cardiopulmonary Testing in HIV Patients

Background

Cardiac magnetic resonance imaging in conjunction with exercise (exMR) and cardiopulmonary testing (CPET) to evaluate cardiopulmonary function has the potential of uncovering poorly understood mechanisms of dyspnea in patients that cannot be otherwise discerned with a single imaging modality.

Purpose

We prospectively evaluated the value of this technique in dyspneic patients with HIV without obvious cardiopulmonary etiologies to comprehensively assess mechanisms of dyspnea.

Methods

Thirty-six HIV patients with dyspnea without obvious cardiopulmonary causes [normal chest x-ray, normal resting LVEF and resting pulmonary artery (PA) pressures <40 mm Hg on echo] and exercise limitation [Modified Medical Research Council (MMRC) dyspnea scale >2] underwent testing using a novel combined exMR/CPET platform (Figure 1). Resting and exercise magnetic resonance imaging (MRI), including flow velocities across the pulmonary artery together with CPET was evaluated at pre and post peak stress. We analyzed the correlation between CPET and MRI pre and peak exercise variables.

Results

The mean age was 51 years; 60% were male; and mean absolute CD4 count was 718. Ventilator efficiency at peak exercise (Peak VO2) did not correlate with exMR parameters. Peak VE/VCO2 was negatively associated with peak LV and RV stroke volume (p values 0.002 & 0.005 respectively). There was a positive relationship between peak petCO2and LV cardiac output (p=0.02), peak exercise RV stroke volume (p=0.003), peak exercise LV stroke volume (p=0.02). Absolute CD4 count was positively correlated with post exercise pulmonary artery velocity (p=0.045). We found no correlation between absolute CD8 count and CMR and CPET exercise parameters.

Figure 1. MRI-CPET setting

Conclusion

HIV patients appear to have an impairment of ventilatory efficiency, exemplified by the association of VE/VCO2and PetCO2 with exMR parameters in the context of normal RV/LV contractile reserve and no evidence of Pulmonary arterial hypertension. A combined CPET/exMRI platform may provide new insight into cardiopulmonary function and the factors influencing exercise tolerance in symptomatic HIV patients.

Acknowledgement/Funding

7R01HL125060-03

Distal chromosome 16p11.2 duplications containing SH2B1 in patients with scoliosis

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) is a common musculoskeletal disorder with strong evidence for a genetic contribution. CNVs play an important role in congenital scoliosis, but their role in idiopathic scoliosis has been largely unexplored.

METHODS

Exome sequence data from 1197 AIS cases and 1664 in-house controls was analysed using coverage data to identify rare CNVs. CNV calls were filtered to include only highly confident CNVs with >10 average reads per region and mean log-ratio of coverage consistent with single-copy duplication or deletion. The frequency of 55 common recurrent CNVs was determined and correlated with clinical characteristics.

RESULTS

Distal chromosome 16p11.2 microduplications containing the gene SH2B1 were found in 0.7% of AIS cases (8/1197). We replicated this finding in two additional AIS cohorts (8/1097 and 2/433), resulting in 0.7% (18/2727) of all AIS cases harbouring a chromosome 16p11.2 microduplication, compared with 0.06% of local controls (1/1664) and 0.04% of published controls (8/19584) (p=2.28×10^-11, OR=16.15). Furthermore, examination of electronic health records of 92 455 patients from the Geisinger health system showed scoliosis in 30% (20/66) patients with chromosome 16p11.2 microduplications containing SH2B1 compared with 7.6% (10/132) of controls (p=5.6×10^-4, OR=3.9).

CONCLUSIONS

Recurrent distal chromosome 16p11.2 duplications explain nearly 1% of AIS. Distal chromosome 16p11.2 duplications may contribute to scoliosis pathogenesis by directly impairing growth or by altering expression of nearby genes, such as TBX6. Individuals with distal chromosome 16p11.2 microduplications should be screened for scoliosis to facilitate early treatment.

Haemosporidian infection and co-infection affect host survival and reproduction in wild populations of great tits

Theoretical studies predict that parasitic infection may impact host longevity and ultimately modify the trade-off between reproduction and survival. Indeed, a host may adjust its energy allocation in current reproduction to balance the negative effects of parasitism on its survival prospects. However, very few empirical studies tested this prediction. Avian haemosporidian parasites provide an excellent opportunity to assess the influence of parasitic infection on both host survival and reproduction. They are represented by three main genera (Plasmodium, Haemoproteus and Leucocytozoon) and are highly prevalent in many bird populations. Here we provide the first known long-term field study (12 years) to explore the effects of haemosporidian parasite infection and co-infection on fitness in two populations of great tits (Parus major), using a multistate modeling framework. We found that while co-infection decreased survival probability, both infection and co-infection increased reproductive success. This study provides evidence that co-infections can be more virulent than single infections. It also provides support for the life-history theory which predicts that reproductive effort can be adjusted to balance one's fitness when survival prospects are challenged.

Multi-mycotoxin screening of feed and feed raw materials from Africa

As animal feed is prone to infestation with mycotoxin-producing fungi, mycotoxin contamination of feed should be monitored. Here, we report a multi-mycotoxin survey of feed samples from Africa. We determined the concentrations of aflatoxins, fumonisins, deoxynivalenol, T-2 toxin, zearalenone and ochratoxin A in 1,045 samples of finished feed and feed raw materials (maize, maize silage, other cereals, etc.) from South Africa and 318 samples from Algeria, Tunisia, Morocco, Senegal, Côte d’Ivoire, Nigeria, Ghana, Namibia, Uganda, Kenya, Tanzania, Zambia and Madagascar. We compared the measured mycotoxin concentrations to regulatory limits or guidance values that are in effect in the European Union and analysed the co-occurrence of these mycotoxins. To determine the occurrence of other fungal secondary metabolites, a subset of the samples was analysed using a multi-analyte liquid chromatography tandem mass spectrometry-based method for the simultaneous detection of over 700 fungal metabolites. We found that 33.3% of maize samples and 54.4% of finished feed samples from Senegal, Côte d’Ivoire, Nigeria, Ghana, Namibia, Uganda, Kenya and Tanzania exceeded the European regulatory limit of 20 ng/g aflatoxins. The Fusarium mycotoxins zearalenone, fumonisins and deoxynivalenol were prevalent in all commodities from all countries, but concentrations were in most cases below European guidance values. Concentrations of deoxynivalenol and zearalenone were correlated. Several other Fusarium metabolites occurred frequently (e.g. moniliformin, beauvericin, aurofusarin) or in high concentrations (e.g. aurofusarin, fusaproliferin). Furthermore, high levels of diplodiatoxin were occasionally detected in samples from South Africa and the Alternaria metabolite tenuazonic acid was prevalent and reached high concentrations. In conclusion, aflatoxins frequently occurred in African feed samples in potentially unsafe concentrations. While Fusarium mycotoxins mostly occurred in concentrations below European guidance values, a correlation between deoxynivalenol and zearalenone concentrations suggests that toxicological interactions of these compounds deserve attention. Several less investigated fungal secondary metabolites occurred frequently or reached high concentrations.

Mycotoxins in Southeast Asian aquaculture: plant-based meals and finished feeds

The awareness of mycotoxin-related issues in aquaculture industry has grown as manufacturers and producers realise the importance of mycotoxins, beyond aflatoxin, and their potential to impact production. During a period of one year (January 2016 – December 2016), 175 samples of different plant proteins, aquaculture/fishery by-products and finished aquaculture feeds, were analysed. Samples were tested for aflatoxins (aflatoxin B1, B2, G1 and G2); zearalenone; type B trichothecenes (deoxynivalenol (DON); nivalenol; 3-acetyldeoxynivalenol; 15-acetyldeoxynivalenol and fusarenon X-glucoside); fumonisins (fumonisin B1, B2 and B3); type A trichothecenes (T-2 and HT-2 toxin; diacetoxyscirpenol and neosolaniol); and ochratoxin A. All samples were sourced in Southeast Asia. Within the analysed samples, 4% were free of detectable mycotoxins. 8% of the samples had one mycotoxin and 88% of the samples were contaminated with more than one mycotoxin. The current work show similarity to previous studies, that mycotoxin occurrence in plant-meals, and consequently in finished feeds, is quite variable and confirms that aflatoxin is not the main mycotoxin in aquafeeds. Mycotoxin occurrence in fish and shrimp feeds in the present samples were higher than reported in previous studies for the same region. In samples of shrimp feed with DON detected, the mean average DON level was 882 μg/kg with a maximum level of 2,287 μg/kg. These values are within the reported sensitivity levels of white leg shrimp (Litopenaeus vannamei). Despite the limited number and short period of sampling, this inventory study helps address a knowledge gap of mycotoxin occurrence in feeds specifically destined for the aquaculture industry.

Manifestation of intra-atomic 5d6s-4f exchange coupling in photoexcited gadolinium

Intra-atomic exchange couplings (IECs) between 5d6s and 4f electrons are ubiquitous in rare-earth metals and play a critical role in spin dynamics. However, detecting them in real time domain has been difficult. Here we show the direct evidence of IEC between 5d6s and 4f electrons in gadolinium. Upon femtosecond laser excitation, 5d6s electrons are directly excited; their majority bands shift toward the Fermi level while their minority bands do the opposite. For the first time, our first-principles minority shift now agrees with the experiment quantitatively. Excited 5d6s electrons lower the exchange potential barrier for 4f electrons, so the 4f states are also shifted in energy, a prediction that can be tested experimentally. Although a significant number of 5d6s electrons, some several eV below the Fermi level, are excited out of the Fermi sea, there is no change in the 4f states, a clear manifestation of intra-atomic exchange coupling.

The inferomedial femoral neck is compromised by age but not disease: Fracture toughness and the multifactorial mechanisms comprising reference point microindentation

The influence of ageing on the fracture mechanics of cortical bone tissue is well documented, though little is known about if and how related material properties are further affected in two of the most prominent musculoskeletal diseases, osteoporosis and osteoarthritis (OA). The femoral neck, in close proximity to the most pertinent osteoporotic fracture site and near the hip joint affected by osteoarthritis, is a site of particular interest for investigation. We have recently shown that Reference Point micro-Indentation (RPI) detects differences between cortical bone from the femoral neck of healthy, osteoporotic fractured and osteoarthritic hip replacement patients. RPI is a new technique with potential for in vivo bone quality assessment. However, interpretation of RPI results is limited because the specific changes in bone properties with pathology are not well understood and, further, because it is not conclusive what properties are being assessed by RPI. Here, we investigate whether the differences previously detected between healthy and diseased cortical bone from the femoral neck might reflect changes in fracture toughness. Together with this, we investigate which additional properties are reflected in RPI measures. RPI (using the Biodent device) and fracture toughness tests were conducted on samples from the inferomedial neck of bone resected from donors with: OA (41 samples from 15 donors), osteoporosis (48 samples from 14 donors) and non age-matched cadaveric controls (37 samples from 10 donoros) with no history of bone disease. Further, a subset of indented samples were imaged using micro-computed tomography (3 osteoporotic and 4 control samples each from different donors) as well as fluorescence microscopy in combination with serial sectioning after basic fuchsin staining (7 osteoporotic and 5 control samples from 5 osteoporotic and 5 control donors). In this study, the bulk indentation and fracture resistance properties of the inferomedial femoral neck in osteoporotic fracture, severe OA and control bone were comparable (p > 0.05 for fracture properties and <10% difference for indentation) but fracture toughness reduced with advancing age (7.0% per decade, r = -0.36, p = 0.029). Further, RPI properties (in particular, the indentation distance increase, IDI) showed partial correlation with fracture toughness (r = -0.40, p = 0.023) or derived elastic modulus (r = -0.40, p = 0.023). Multimodal indent imaging revealed evidence of toughening mechanisms (i.e. crack deflection, bridging and microcracking), elastoplastic response (in terms of the non-conical imprint shape and presence of pile-up) and correlation of RPI with damage extent (up to r = 0.79, p = 0.034) and indent size (up to r = 0.82, p < 0.001). Therefore, crack resistance, deformation resistance and, additionally, micro-structure (porosity: r = 0.93, p = 0.002 as well as pore proximity: r = -0.55, p = 0.027 for correlation with IDI) are all contributory to RPI. Consequently, it becomes clear that RPI measures represent a multitude of properties, various aspects of bone quality, but are not necessarily strongly correlated to a single mechanical property. In addition, osteoporosis or osteoarthritis do not seem to further influence fracture toughness of the inferomedial femoral neck beyond natural ageing. Since bone is highly heterogeneous, whether this finding can be extended to the whole femoral neck or whether it also holds true for other femoral neck quadrants or other material properties remains to be shown.

Variability in reference point microindentation and recommendations for testing cortical bone: maximum load, sample orientation, mode of use, sample preparation and measurement spacing

Reference Point Indentation (RPI) is a novel microindentation tool that has emerging clinical potential for the assessment of fracture risk as well as use as a laboratory tool for straight-forward mechanical characterisation of bone. Despite increasing use of the tool, little research is available to advise the set-up of testing protocols or optimisation of testing parameters. Here we consider five such parameters: maximum load, sample orientation, mode of use, sample preparation and measurement spacing, to investigate how they affect the Indentation Distance Increase (IDI), the most published measurement parameter associated with the RPI device. The RPI tool was applied to bovine bone; indenting in the proximal midshaft of five femora and human bone; indenting five femoral heads and five femoral neck samples. Based on the findings of these studies we recommend the following as the best practice. (1) Repeat measurements should be utilised to reduce the coefficient of variation (e.g. 8-15 repeats to achieve a 5-10% error, however the 3-5 measurements used here gives a 15-20% error). (2) IDI is dependent on maximum load (r=0.45 on the periosteal surface and r=0.94 on the machined surface, p<0.05), mode of use (i.e. comparing the device held freehand compared to fixed in its stand, p=0.04) and surface preparation (p=0.004) so these should be kept consistent throughout testing. Though sample orientation appears to have minimal influence on IDI (p>0.05), care should also be taken in combining measurements from different orientations. (3) The coefficient of variation is higher (p=0.04) when holding the device freehand, so it should ideally be kept supported in its stand. (4) Removing the periosteum (p=0.04) and machining the surface of the bone (p=0.08) reduces the coefficient of variation, so should be performed where practical. (5) There is a hyperbolic relationship between thickness and IDI (p<0.001) with a sample thickness 10 fold greater than the maximum indentation depth recommended, to ensure a representative measurement. (6) Measurement spacing does not appear to influence the IDI (p>0.05), so it can be as low as 500 µm. By following these recommendations, RPI users can minimise the potential confounding effects associated with the variables investigated here and reduce the coefficient of variation, hence achieving more consistent testing. This optimisation of the technique enhances both the clinical and laboratory potential of the tool.

Cardiovascular risk and bone loss in men undergoing androgen deprivation therapy for non-metastatic prostate cancer: implementation of standardized management guidelines

Our objective was to evaluate the effectiveness of implementing standardized guidelines to mitigate metabolic and bone side effects of androgen deprivation therapy (ADT) in men with non-metastatic prostate cancer. We conducted a 2-year prospective cohort study at a tertiary referral teaching hospital. Overall, 236 men (mean age 69.8 ± 7.1) commencing ADT for non-metastatic prostate cancer attended a baseline clinic visit between 2007 and 2011, and 153 men were eligible for follow-up after 2 years of continuous ADT. Of these, 113 men had data available for analysis at 2 years. At baseline, 87% of the men were overweight or obese, 61% had hypertension, 56% had hypercholesterolaemia, 27% prior cardiovascular disease, 11% osteoporosis and 40% osteopaenia. After 2 years of ADT, there was an increase in waist circumference (+2.8 ± 6.3 cm, p = 0.002), and, in men without diabetes, in HbA1c (+0.13 ± 0.34%, p = 0.019). Despite this, due to treatment, there were significant reductions in total cholesterol (-0.35 ± 1.00 mmol/L, p < 0.001), and blood pressure (systolic -7.6 ± 19.3 mmHg; diastolic -4.7 ± 11.6 mmHg, p < 0.001). After 2 years, men not receiving anti-resorptive therapy experienced a significant decline in lumbar spine (-0.042 ± 0.134 g/cm(2) , p = 0.012) and total hip bone mineral density (BMD) (-0.026 ± 0.036 g/cm(2) , p < 0.001), whereas bisphosphonate treatment maintained stable BMD. Prevalence of anaemia increased from 13.8 to 32.5%. Older age independently predicted a greater drop in haemoglobin (p = 0.005). We conclude that a structured approach to assess and treat men undergoing ADT effectively improves cardiovascular risk factors and prevents bone decay. Larger studies are needed to determine effects on cardiovascular outcomes, fracture prevention and survival.

Bariatric surgery for adolescents

Obesity is no longer just an adult disease. An increasing number of youth are overweight, defined as body mass index (BMI) at or greater than the 95th percentile for age (1). Between 2009 and 2010, 16.9% of children aged 2–19 yr were classified as overweight based on BMI (2), as compared with only 5% of children affected by obesity in 1976–1980 (3). This is a problem of enormous proportion from a public health standpoint, as without intervention these children will grow up to become overweight and obese adults. For an obese child, the risk of becoming an obese adult may be as high as 77%, compared with 7%for a child of healthy weight (4). Morbid obesity is a major risk factor for later complications such as cardiovascular disease, type 2 diabetes, obstructive sleep apnea (OSA), polycystic ovary syndrome (PCOS), and degenerative joint disease (4–10). Obesity is also an expensive problem: the US government spends $147 billion yearly on obesity-related healthcare costs (11). Thus, there is an urgent need to target obesity in the pediatric population, before the expensive and life-threatening consequences of obesity manifest. Unfortunately, the effectiveness of medical treatments for obesity is limited. Behaviorally based dietary and physical activity interventions offer little benefit for pediatric obesity, while pharmacologic therapy is also limited and carries low success rates and recidivism (12–14) (Table 1).

TYPES OF ALBINISM IN THE BLACK SOUTHERN AFRICA POPULATION

BACKGROUND

Oculocutaneous albinism (OCA) is the most common inherited disorder in Southern African blacks and several types have been described. Molecular techniques, where available, can be used to confirm a clinical diagnosis and the type of OCA, if necessary, and for prenatal diagnosis.

OBJECTIVES

To investigate and classify the different types of albinism commonly found and to determine the clinical implications for each type.

DESIGN

A descriptive survey.

SETTING

Gauteng province, South Africa, and Lesotho.

SUBJECTS

Three groups of subjects with OCA (96 from a genetics clinic, 62 from a dermatology clinic, and 31 from community surveys) from the black African population participated.

MAIN OUTCOME MEASURES

Subjects underwent clinical and/or dermatological examinations and were then classified according to type of OCA.

RESULTS

Four forms of OCA were identified: most (82%) subjects had OCA2 (a tyrosinase- positive type) with three sub-types: those without large freckles (ephelides) on exposed areas (named OCA 2a in this study), those with such freckles (named OCA 2b), and those with brown albinism (BOCA); the remainder had red/rufous albinism, ROCA (OCA 3). The four forms could be distinguished from each other clinically without using molecular genetic testing.

CONCLUSION

The most common types of albinism found in the black population of Southern Africa are OCA2 and OCA3. Given the high prevalence of the disorder, together with the high risk of skin cancer, and the recent persecution of affected individuals in certain East African countries, these findings and their clinical implications have significance in terms of both education and awareness for health professionals and lay people caring for those with albinism.

Genetic structure in a dynamic baboon hybrid zone corroborates behavioural observations in a hybrid population

Behaviour and genetic structure are intimately related: mating patterns and patterns of movement between groups or populations influence the movement of genetic variation across the landscape and from one generation to the next. In hybrid zones, the behaviour of the hybridizing taxa can also impact the incidence and outcome of hybridization events. Hybridization between yellow baboons and anubis baboons has been well documented in the Amboseli basin of Kenya, where more anubis-like individuals tend to experience maturational and reproductive advantages. However, it is unknown whether these advantages are reflected in the genetic structure of populations surrounding this area. Here, we used microsatellite genotype data to evaluate the structure and composition of baboon populations in southern Kenya. Our results indicate that, unlike for mitochondrial DNA, microsatellite-based measures of genetic structure concord with phenotypically based taxonomic distinctions and that the currently active hybrid zone is relatively narrow. Isolation with migration analysis revealed asymmetric gene flow in this region from anubis populations into yellow populations, in support of the anubis-biased phenotypic advantages observed in Amboseli. Populations that are primarily yellow but that receive anubis gene flow exhibit higher levels of genetic diversity than yellow populations far from the introgression front. Our results support previous work that indicates a long history of hybridization and introgression among East African baboons. Specifically, it suggests that anubis baboons are in the process of gradual range expansion into the range of yellow baboons, a pattern potentially explained by behavioural and life history advantages that correlate with anubis ancestry.

Oculopharyngeal myopathy with inflammation and calcinosis: an unusual phenotype

The case is reported of a patient with progressive proximal and distal weakness, dysphagia, respiratory weakness, calcifications, ptosis and ophthalmoparesis with inflammation, rimmed vacuoles and positive amyloid and ubiquitin on muscle biopsy. The histopathological features fit best with inclusion body myositis, but ophthalmoparesis and ptosis have not previously been described. The clinical phenotype fits best with hereditary inclusion body myopathy or distal-oculopharyngeal muscular dystrophy, but the degree of inflammation seen is unusual. None of these are associated with calcinosis.

Two unrelated children with distal long arm deletion of chromosome 7: clinical features, cytogenetic and gene marker studies

Two phenotypically abnormal, unrelated children with deletion of the distal segment of 7q (7q32 leads to pter) are described. In one instance the mother was the carrier of a balanced translocation between chromosomes 6 and 7, and in the second case the deletion was a de novo event. Their phenotype were compared to previously reported cases and found to have many non-specific clinical features in common. Gene marker studies for some of the genes tentatively localized to chromosome 7 showed no anomalous segregation. The Hageman coagulation factor (Factor XII) activity in both probands was normal, and heterozygosity for alleles of the Kidd blood group in the first proband excludes assignment of the Kidd locus to the distal portion of chromosome 7q.

The impact of HIV/AIDS on blood transfusion practice in South Africa: some ethical issues

Blood transfusion has become an essential component of modern medical practice. However, worldwide epidemics of viral diseases - in particular, HIV/AIDS - have made the practice of blood transfusion therapy hazardous, motivating scientists to devise techniques and strategies to ensure the supply of safe blood and blood components for clinical use. The challenges are particularly great in sub-Saharan Africa, where clinicians have become so accustomed to using blood transfusion that it may be difficult for them to reduce their dependence on it. A number of ethical issues raised by the practice of blood transfusion in medicine are raised and discussed.

Effects of Feeding Oxidized Fat With or Without Dietary Antioxidants on Nutrient Digestibility, Microbial Nitrogen, and Fatty Acid Metabolism

A dual-effluent continuous culture system was used to investigate, in a 2 x 2 factorial design, the effect of feeding a fresh (FF) or oxidized (OF) blend of unsaturated fats (33% fish oil, 33% corn oil, 26% soybean oil, and 7% inedible tallow) when supplemented with a blend of antioxidants (AO; Agrado Plus, Novus International Inc.; Agrado Plus is a trademark of Novus International Inc. and is registered in the United States and other countries) on nutrient digestibility, bacterial protein synthesis, and fatty acid metabolism. Twice a day for 10 d, 12 fermenters were fed a diet that consisted of 52% forage and 48% grain mixture that contained 3% (dry matter basis) FF or OF, with or without AO. The OF contained a higher concentration of peroxides (215 vs. 3.5 mEq/kg), and a lower concentration of unsaturated fatty acids than the FF. Feeding OF reduced nitrogen digestibility, microbial nitrogen yield, and efficiency (expressed as kilograms of dry matter digested) and increased the outflow of saturated fatty acids in the effluent when compared with feeding FF. Adding AO improved total carbohydrate, neutral, and acid detergent fiber digestibilities and the amount of digested feed nitrogen converted to microbial nitrogen across the types of fats. From this study, we concluded that feeding OF reduced microbial nitrogen and increased the outflow of saturated fatty acids. Feeding AO improved fiber digestibility by rumen microorganisms, regardless of the type of fat.

Toward endobronchial Ir-192 high-dose-rate brachytherapy therapeutic optimization

A number of patients with lung cancer receive either palliative or curative high-dose-rate (HDR) endobronchial brachytherapy. Up to a third of patients treated with endobronchial HDR die from hemoptysis. Rather than accept hemoptysis as an expected potential consequence of HDR, we have calculated the radial dose distribution for an Ir-192 HDR source, rigorously examined the dose and prescription points recommended by the American Brachytherapy Society (ABS), and performed a radiobiological-based analysis. The radial dose rate of a commercially available Ir-192 source was calculated with a Monte Carlo simulation. Based on the linear quadratic model, the estimated palliative, curative and blood vessel rupture radii from the center of an Ir-192 source were obtained for the ABS recommendations and a series of customized HDR prescriptions. The estimated radius at risk for blood vessel perforation for the ABS recommendations ranges from 7 to 9 mm. An optimized prescription may in some situations reduce this radius to 4 mm. The estimated blood perforation radius is generally smaller than the palliative radius. Optimized and individualized endobronchial HDR prescriptions are currently feasible based on our current understanding of tumor and normal tissue radiobiology. Individualized prescriptions could minimize complications such as fatal hemoptysis without sacrificing efficacy. Fiducial stents, HDR catheter centering or spacers and the use of CT imaging to better assess the relationship between the catheter and blood vessels promise to be useful strategies for increasing the therapeutic index of this treatment modality. Prospective trials employing treatment optimization algorithms are needed.

Pregnancy, Bovine Somatotropin, and Dietary n-3 Fatty Acids in Lactating Dairy Cows: III. Fatty Acid Distribution

Our objective was to examine effects of exogenous bovine somatotropin (bST), pregnancy, and dietary fatty acids on fatty acid distribution in various tissues of lactating dairy cows. Two diets were fed, starting about 17 d in milk (DIM), in which oil of whole cottonseed (control diet) was compared with a calcium salt of fish oil-enriched lipid (FO; 1.9% of dietary DM). Starting at 44 +/- 5 DIM, ovulation was synchronized with a presynchronization plus Ovsynch protocol (d 0 = time of synchronized ovulation). Some cows were inseminated (77 +/- 12 DIM) to create a pregnant group. On d 0 and 11, cows received bST (500 mg) or no bST, and were killed on d 17 (94 +/- 12 DIM). Number of cows in control group was 5 bST-treated cyclic (bST-C), 5 non-bST-treated cyclic (no bST-C), 4 bST-treated pregnant (bST-P), and 5 non-bST-treated pregnant (no bST-P) cows; and for the FO diet: 4 bST-treated (bST-FO-C) and 5 non-bST-treated cyclic (no bST-FO-C) cows. At slaughter, samples of endometrium, liver, muscle, s.c. adipose, internal adipose, and mammary gland were collected. Milk was collected at 75 +/- 5 DIM. Gas chromatography was used to determine fatty acid percentages in tissues and milk fat. Endometrium from the cows fed FO had increased proportions of C20:5 and C22:6, whereas C20:4 was decreased. Injections of bST reduced both C18:2 and the n-6:n-3 ratio, but increased C22:6 in endometrium of cyclic control-fed, but not pregnant cows. In addition, FO decreased the n-6:n-3 ratio in all tissues and milk fat except for s.c. and internal adipose tissue. Cows fed FO also had increased C18:3, C20:5, and C22:6 in the liver and mammary tissue, and C18:3 and C22:6 were increased in the milk fat. The FO diet decreased the Delta9-desaturase index [(product of Delta9-desaturase]/(product of Delta9-desaturase + substrate of Delta9-desaturase]; DIX) in muscle and s.c. tissues, accompanied by an increase in saturated fatty acid (SFA) percentage. In addition, FO diet decreased DIX in the endometrium. In mammary and internal adipose tissues, bST increased DIX in cyclic control-fed cows, whereas bST decreased DIX in FO-fed cows, with no difference in the concentration of SFA and UNSFA. Cis-9, trans-11 conjugated linoleic acid was increased in milk fat, but decreased in the muscle and s.c. adipose tissue of FO-fed cows. The FO-enriched lipid, bST treatment, and early pregnancy can alter fatty acid percentages and distributions that may alter tissue functionality and functional nutrients of consumer products.

Evidence for a multivalent interaction of symmetrical, N-linked, lidocaine dimers with voltage-gated Na+ channels

The interaction of symmetrical lidocaine dimers with voltage-gated Na+ channels (VGSCs) was examined using a FLIPR membrane potential assay and voltage-clamp. The dimers, in which the tertiary amines of the lidocaine moieties are linked by an alkylene chain (two to six methylene units), inhibited VGSC activator-evoked depolarization of cells heterologously-expressing rat (r) Na(v)1.2a, human (h) Na(v)1.5, and rNa(v)1.8, with potencies 10- to 100-fold higher than lidocaine (compound 1). The rank order of potency (C4 (compound 4) > C3 (compound 3) > or = C2 (compound 2) = C5 (compound 5) = C6 (compound 6) >> compound 1) was similar at each VGSC. Compound 4 exhibited strong use-dependent inhibition of hNa(v)1.5 with pIC50 values < 4.5 and 6.0 for tonic and phasic block, respectively. Coincubation with local anesthetics but not tetrodotoxin attenuated compound 4-mediated inhibition of hNa(v)1.5. These data suggest that the compound 4 binding site(s) is identical, or allosterically coupled, to the local anesthetic receptor. The dissociation rate of the dimers from hNa(v)1.5 was dependent upon the linker length, with a rank order of compound 1 > compound 5 = compound 6 > compound 2 >> compound 3. The observation that both the potency and dissociation rate of the dimers was dependent upon linker length is consistent with a multivalent interaction at VGSCs. hNa(v)1.5 VGSCs did not recover from inhibition by compound 4. However, "chase" with free local anesthetic site inhibitors increased the rate of dissociation of compound 4. Together, these data support the hypothesis that compound 4 simultaneously occupies two binding sites on VGSCs, both of which can be bound by known local anesthetic site inhibitors.