Clinical impact of preemptive pharmacogenomic testing on antiplatelet therapy in a real-world setting

CYP2C19 genotyping to guide antiplatelet therapy after patients develop acute coronary syndromes (ACS) or require percutaneous coronary interventions (PCIs) reduces the likelihood of major adverse cardiovascular events (MACE). Evidence about the impact of preemptive testing, where genotyping occurs while patients are healthy, is lacking. In patients initiating antiplatelet therapy for ACS or PCI, we compared medical records data from 67 patients who received CYP2C19 genotyping preemptively (results >7 days before need), against medical records data from 67 propensity score-matched patients who received early genotyping (results within 7 days of need). We also examined data from 140 patients who received late genotyping (results >7 days after need). We compared the impact of genotyping approaches on medication selections, specialty visits, MACE and bleeding events over 1 year. Patients with CYP2C19 loss-of-function alleles were less likely to be initiated on clopidogrel if they received preemptive rather than early or late genotyping (18.2%, 66.7%, and 73.2% respectively, p = 0.001). No differences were observed by genotyping approach in the number of specialty visits or likelihood of MACE or bleeding events (all p > 0.21). Preemptive genotyping had a strong impact on initial antiplatelet selection and a comparable impact on patient outcomes and healthcare utilization, compared to genotyping ordered after a need for antiplatelet therapy had been identified.

Evolution of pharmacogenomic services and implementation of a multi-state pharmacogenomics clinic across a large rural healthcare system

Introduction: Pharmacogenomics (PGx) aims to maximize drug benefits while minimizing risk of toxicity. Although PGx has proven beneficial in many settings, clinical uptake lags. Lack of clinician confidence and limited availability of PGx testing can deter patients from completing PGx testing. A few novel PGx clinic models have been described as a way to incorporate PGx testing into the standard of care. Background: A PGx clinic was implemented to fill an identified gap in provider availability, confidence, and utilization of PGx across our health system. Through a joint pharmacist and Advanced Practice Provider (APP) collaborative clinic, patients received counseling and PGx medication recommendations both before and after PGx testing. The clinic serves patients both in-person and virtually across four states in the upper Midwest. Results: The majority of patients seen in the PGx clinic during the early months were clinician referred (77%, n = 102) with the remainder being self-referred. Patients were, on average, taking two medications with Clinical Pharmacogenetics Implementation Consortium guidelines. Visits were split almost equally between in-person and virtual visits. Conclusion: Herein, we describe the successful implementation of an interdisciplinary PGx clinic to further enhance our PGx program. Throughout the implementation of the PGx clinic we have learned valuable lessons that may be of interest to other implementors. Clinicians were actively engaged in clinic referrals and early adoption of telemedicine was key to the clinic's early successes.

Attitudes about pharmacogenomic testing vary by healthcare specialty

Aim: To understand how attitudes toward pharmacogenomic (PGx) testing among healthcare providers varies by specialty. Methods: Providers reported comfort ordering PGx testing and its perceived utility on web-based surveys before and after genetics education. Primary quantitative analyses compared primary care providers (PCPs) to specialty providers at both timepoints. Results: PCPs were more likely than specialty care providers to rate PGx testing as useful at both timepoints. Education increased comfort ordering PGx tests, with larger improvements among PCPs than specialty providers. Over 90% of cardiology and internal medicine providers rated PGx testing as useful at pre- and post-education. Conclusion: PCPs overwhelmingly perceive PGx to be useful, and provider education is particularly effective for improving PCPs' confidence. Education for all specialties will be essential to ensure appropriate integration into routine practice.

SLCO1B1 gene-based clinical decision support reduces statin-associated muscle symptoms risk with simvastatin

Background: SLCO1B1 variants are known to be a strong predictor of statin-associated muscle symptoms (SAMS) risk with simvastatin. Methods: The authors conducted a retrospective chart review on 20,341 patients who had SLCO1B1 genotyping to quantify the uptake of clinical decision support (CDS) for genetic variants known to impact SAMS risk. Results: A total of 182 patients had 417 CDS alerts generated, and 150 of these patients (82.4%) received pharmacotherapy that did not increase risks for SAMS. Providers were more likely to cancel simvastatin orders in response to CDS alerts if genotyping had been done prior to the first simvastatin prescription than after (94.1% vs 28.5%, respectively; p < 0.001). Conclusion: CDS significantly reduces simvastatin prescribing at doses associated with SAMS.

Patient satisfaction with return of pharmacogenomic results utilizing a patient portal message

Background: Returning pharmacogenomics (PGx) results to patients is complex and challenging. Patients prefer provider education; however, a gap in provider comfort in PGx results has been documented. Objectives: This study's purpose was to evaluate satisfaction with the return of PGx test results using a patient portal message. Methods: A survey was sent to two cohorts with PGx results, one that received a PGx result message and one that did not. Results: Following implementation of the PGx result message, there was a decrease in patients reporting negative responses surrounding satisfaction in the return of their PGx results, with 39% responding negatively pre-implementation and 21% post-implementation. Conclusion: Satisfaction with the return of results improved following the implementation of a patient portal message.

Evaluating the genetic consequences of population subdivision as it unfolds and how to best mitigate them: A rare story about koalas

The genetic consequences of the subdivision of populations are regarded as significant to long-term evolution, and research has shown that the scale and speed at which this is now occurring is critically reducing the adaptive potential of most species which inhabit human-impacted landscapes. Here, we provide a rare and, to our knowledge, the first analysis of this process while it is happening and demonstrate a method of evaluating the effect of mitigation measures such as fauna crossings. We did this by using an extensive genetic data set collected from a koala population which was intensely monitored during the construction of linear transport infrastructure which resulted in the subdivision of their population. First, we found that both allelic richness and effective population size decreased through the process of population subdivision. Second, we predicted the extent to which genetic drift could impact genetic diversity over time and showed that after only 10 generations the resulting two subdivided populations could experience between 12% and 69% loss in genetic diversity. Lastly, using forward simulations we estimated that a minimum of eight koalas would need to disperse from each side of the subdivision per generation to maintain genetic connectivity close to zero but that 16 koalas would ensure that both genetic connectivity and diversity remained unchanged. These results have important consequences for the genetic management of species in human-impacted landscapes by showing which genetic metrics are best to identify immediate loss in genetic diversity and how to evaluate the effectiveness of any mitigation measures.

Progression of precision statin prescribing for reduction of statin-associated muscle symptoms

Background: Statins are among the most commonly prescribed medications, and improve patient outcomes by lowering cholesterol levels, but also have side effects. Variations in statin response can be attributed to a handful of factors that include pharmacogenetics. Methods: While not a true review article, this work was written using various search engines and terms and previous and newly published Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for statins to provide a historical perspective in addition to the current status of statin-related pharmacogenetics and future perspectives. Results: This article provides historical background on statins and associated adverse effects, reviews pharmacogenetic implications, applies clinical-decision support, incorporates the latest CPIC guidelines and addresses future implications. Conclusion: Statins are a beneficial medication, but not without risk. Pharmacogenomics can help mitigate some risk factors. Clinical-decision support, implementation, research and guidelines will continue to influence statin prescribing.

SARS-CoV-2 prevalence and immunity: a hospital-based study from Malawi

Background

COVID-19 transmission and disease dynamics in sub-Saharan Africa are not well understood. Our study aims to provide insight into COVID-19 epidemiology in Malawi by estimating SARS-CoV-2 prevalence and immunity after SARS-CoV-2 infection in a hospital-based setting.

Methods

We conducted a hospital-based, convenience sampling, cross-sectional survey for SARS-CoV-2 in Lilongwe, Malawi. Participants answered a questionnaire and were tested for SARS-CoV-2 by enzyme-linked immunosorbent assay and real-time reverse-transcription polymerase chain reaction (RT-PCR). A surrogate virus neutralization test (sVNT) was performed in seropositive samples to estimate immunity. Poisson regression was used to assess SARS-CoV-2 point prevalence association with demographic and behavioral variables.

Findings

The study included 930 participants. We found a combined point prevalence of 10.1%. Separately analyzed, RT-PCR positivity was 2.0%, and seropositivity was 9.3%. Of tested seropositive samples, 90.1% were sVNT positive. We found a high rate (45.7%) of asymptomatic SARS-CoV-2 infection. SARS-CoV-2 point prevalence was significantly associated with being a healthcare worker.

Interpretation

Our study suggests that official data underestimate COVID-19 transmission. Using sVNTs to estimate immunity in Malawi is feasible and revealed considerable post-infection immunity in our cohort. Subclinical infection and transmission are probably a game-changer in surveillance, mitigation and vaccination strategies.

Precision Population Medicine in Primary Care: The Sanford Chip Experience

Genetic testing has the potential to revolutionize primary care, but few health systems have developed the infrastructure to support precision population medicine applications or attempted to evaluate its impact on patient and provider outcomes. In 2018, Sanford Health, the nation's largest rural nonprofit health care system, began offering genetic testing to its primary care patients. To date, more than 11,000 patients have participated in the Sanford Chip Program, over 90% of whom have been identified with at least one informative pharmacogenomic variant, and about 1.5% of whom have been identified with a medically actionable predisposition for disease. This manuscript describes the rationale for offering the Sanford Chip, the programs and infrastructure implemented to support it, and evolving plans for research to evaluate its real-world impact.

Evaluation of VIDAS Listeria monocytogenes II (LMO2) Immunoassay Method for the Detection of Listeria monocytogenes in Foods: Collaborative Study

A multilaboratory study was conducted to compare the VIDAS®Listeria monocytogenes II (LMO2) immunoassay and the standard cultural methods for the detection of Listeria monocytogenes in foods. Five food types—vanilla ice cream, brie cheese, cooked roast beef, frozen green beans, and frozen tilapia fish—at 3 levels were analyzed by each method. A total of 26 laboratories representing government and industry participated. In this study, 1404 test portions were analyzed of which 1152 were used in the statistical analysis. There were 448 positive by the VIDAS LMO2 assay and 457 positive by the standard culture methods. A χ2 analysis of each of the 5 food types, at the 3 inoculation levels tested, was performed. The resulting χ2 value, 0.36, indicates that overall, there are no statistical differences between the VIDAS LMO2 assay and the standard methods at the 5% level of significance.

Evaluation of the VIDAS® Listeria (LIS) Immunoassay for the Detection of Listeria in Foods Using Demi-Fraser and Fraser Enrichment Broths, as Modification of AOAC Official Method 999.06 (AOAC Official Method 2004.06)

A multilaboratory study was conducted to compare the VIDAS® LIS immunoassay with the standard cultural methods for the detection of Listeria in foods using an enrichment modification of AOAC Official Method 999.06. The modified enrichment protocol was implemented to harmonize the VIDAS LIS assay with the VIDAS LMO2 assay. Five food types—brie cheese, vanilla ice cream, frozen green beans, frozen raw tilapia fish, and cooked roast beef—at 3 inoculation levels, were analyzed by each method. A total of 15 laboratories representing government and industry participated. In this study, 1206 test portions were tested, of which 1170 were used in the statistical analysis. There were 433 positive by the VIDAS LIS assay and 396 positive by the standard culture methods. A Chi-square analysis of each of the 5 food types, at the 3 inoculation levels tested, was performed. The resulting average Chi square analysis, 0.42, indicated that, overall, there are no statistical differences between the VIDAS LIS assay and the standard methods at the 5% level of significance.

Evaluation of the BAX® System for Detection of Listeria monocytogenes in Foods: Collaborative Study

A multilaboratory study was conducted to compare the automated BAX® system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.

Evaluation of VIDAS® Immuno-Concentration Salmonella/VIDAS Salmonella Immunoassay Method for Detection of Salmonella in Selected Foods: Collaborative Study

The VIDAS Immuno-concentration Salmonella (ICS)/VIDAS Salmonella (SLM) immunoassay method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1266 of the 1440 samples. Of the 174 samples not in agreement, 69 were VIDAS ICS/SLM-positive and BAM/AOAC-negative and 105 were VIDAS ICS/SLM-negative and BAM/AOAC-positive.

Evaluation of VIDAS® Immuno-Concentration Salmonella Assay Plus Selective Plate Method (Hektoen Enteric, Bismuth Sulfite, Salmonella Identification) for Detection of Salmonella in Selected Foods: Collaborative Study

The VIDAS Immuno-concentration Salmonella (ICS) plus selective plate method (Hektoen enteric, bismuth sulfite, Salmonella identification) method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1283 of the 1440 test samples. Of the 157 test samples not in agreement, 82 were VIDAS ICS plus selective plate-positive and BAM/AOAC-negative, and 75 were VIDAS ICS plus selective plate-negative and BAM/AOAC-positive.

Salmonella in Selected Foods by VIDAS® Immuno-Concentration Salmonella Plus Selective Plate Method (Hektoen Enteric, Xylose Lysine Desoxycholate, Bismuth Sulfite): Collaborative Study

The VIDAS Immuno-concentration Salmonella (ICS) plus selective plate method (Hektoen enteric, xylose lysine desoxycholate, bismuth sulfite) method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1297 of the 1455 samples. Of the 158 samples not in agreement, 82 were VIDAS ICS plus selective plate-positive and BAM/AOAC-negative, and 76 were VIDAS ICS plus selective plate-negative and BAM/AOAC-positive.

VIDAS® Enzyme-Linked Immunofluorescent Assay for Detection of Listeria in Foods: Collaborative Study

The VIDAS LIS method and the traditional culture methods for detection of Listeria species in food were evaluated in a multilaboratory comparative study. The 6 foods tested were either naturally contaminated or inoculated with 3 different concentrations of Listeria. Results for each food and each contamination level with the VIDAS LIS method were as good as or better than those obtained with the traditional culture method. Of 1558 samples tested, 935 were positive: 839 by the VIDAS method and 809 by standard culture methods. Overall false negative rates were 10.3 and 13.5% for the VIDAS LIS and culture methods, respectively. The false positive rate for the VIDAS LIS assay was 1.4% based on 9 VIDAS LIS positive assays that did not confirm positive by isolation of Listeria. The agreement between the VIDAS LIS and culture methods for all samples tested was 86%.

An introduction to clinical trial design

Clinicians and other decision makers in healthcare use results from clinical trials to inform practice. Interpretation of clinical trial results can be challenging, as weaknesses in trial design, data collection, analysis or reporting, can compromise the usefulness of results. A good working knowledge of clinical trial design is essential to expertly interpret and determine the validity and generalizability of the results. This manuscript will give a brief overview of clinical trial design including the strengths and limitations of various approaches. The focus will be on confirmatory clinical trials.

Implementation of wide-scale pharmacogenetic testing in primary care

The convergence of translational genomics and biomedical informatics has changed healthcare delivery. Institutional consortia have begun implementing lab testing and decision support for drug–gene interactions. Aggregate datasets are now revealing the impact of clinical decision support for drug–gene interactions. Given the pleiotropic nature of pharmacogenes, interdisciplinary teams and robust clinical decision support tools must exist within an informatics framework built to be flexible and capable of cross-talk between clinical specialties. Navigation of the challenges presented with the implementation of five steps to build a genetics program infrastructure requires the expertise of multiple healthcare professionals. Ultimately, this manuscript describes our efforts to place pharmacogenomics in the hands of the primary care provider integrating this information into a patient’s healthcare over their lifetime.

The Differential Anti-HIV Effect of a New Humic Substance-Derived Preparation in Diverse Cells of the Immune System

The anti-HIV activity of a new humic substance-derived preparation has been studied in individual pools of immune cells (CD4+ T lymphocytes, macrophages, dendritic cells). Near-complete inhibition of the HIV infection (by more than 90%) was achieved by treating each of the abovementioned cell types with non-toxic concentrations of the preparation. The inhibitory effect demonstrates the possibility of preventing the depletion of a significant portion of functionally important immune cells. A comparative study of infection inhibition in individual cell pools has allowed us to reveal the differences in the preparation's effectiveness in each of the cell populations. A R5-tropic HIV-1 infection in macrophages exhibited maximum sensitivity to the preparation: 90% and 50% inhibition of the infection were observed in the presence of concentrations as low as 1.4 and 0.35 μg/ml, respectively. A 15- and 19-fold higher concentration was required to achieve the same extent of inhibition in dendritic cells infected with the same strain. The effectiveness of the drug in CD4 + T lymphocytes is quite comparable to its effectiveness in macrophages. The drug is universally effective for both the T- and M-tropic variants of HIV-1.

Testing the Gaussianity of the Human EEG During Anesthesia

The Gaussian properties of human EEGs, which were measured over various stages of general anesthesia, were tested. The basis of the method was to describe the EEG signals by autoregressive models and to test the normality of the regression residuals with the Shapiro-Wilk statistic. The results show that in general the human EEG during anesthesia can be considered as a realization of a Gaussian stochastic process.

Application of Adjusted Survival Curves to Renal Transplant Data

An important means in the analysis of survival time data is the estimation and graphical representation of survival probabilities. In this paper unifactorial parametric and non-parametric survival curve estimators and two types of adjusted survival curves based on a parametric multifactorial approach are applied to renal transplant data. It is shown that the resulting survival curves can differ substantially. The unifactorial survival curves yield biased results in case of serious disequilibrium in the data. This drawback of the unifactorial methods has been overcome by the use of adjusted survival curves which take possible distortions in the data set into account. The benefits of adjusted survival curves in assessing potentially prognostic factors are elucidated by the application to data from renal transplantation.

Current options in aerosolised drug therapy for children receiving respiratory support

Inhalation of aerosolised medications are the mainstay of treatment for a number of chronic lung diseases and have several advantages over systemically-administered medications. These include more rapid onset of action for drugs such as β-adrenergic agonists when compared with oral medication, high luminal doses for inhaled antibiotics when used to treat endobronchial infection, and an improved therapeutic index compared with systemic delivery for these and other classes of drugs such as corticosteroids. The use of aerosolised drugs to treat patients whose tracheas are intubated is less well established, in part because systemic delivery via the intravenous route can be a simpler alternative for many drugs. Consequently, research in this area is largely limited to a number of in vitro studies and very few clinical trials. Unfortunately, a lack of focus in this area has resulted in a number of practices which at best are ineffective, and at worst dangerous for the patient. Although there have been some attempts to re-invigorate research in order to improve delivery systems, current devices are, to a great extent, based on long-standing technology developed more than 50 years ago. In this review, we explore current knowledge and provide guidance as to when and how the inhaled route may be of value when treating patients whose tracheas are intubated, and we set out the challenges facing those attempting to advance the topic. We conclude by reviewing current areas of interest that may lead to more effective and widespread use of aerosols in the treatment of intubated patients.

IDENTIFYING CANCER SPECIFIC METABOLIC SIGNATURES USING CONSTRAINT-BASED MODELS

Cancer metabolism differs remarkably from the metabolism of healthy surrounding tissues, and it is extremely heterogeneous across cancer types. While these metabolic differences provide promising avenues for cancer treatments, much work remains to be done in understanding how metabolism is rewired in malignant tissues. To that end, constraint-based models provide a powerful computational tool for the study of metabolism at the genome scale. To generate meaningful predictions, however, these generalized human models must first be tailored for specific cell or tissue sub-types. Here we first present two improved algorithms for (1) the generation of these context-specific metabolic models based on omics data, and (2) Monte-Carlo sampling of the metabolic model ux space. By applying these methods to generate and analyze context-specific metabolic models of diverse solid cancer cell line data, and primary leukemia pediatric patient biopsies, we demonstrate how the methodology presented in this study can generate insights into the rewiring differences across solid tumors and blood cancers.

The effect of mild and moderate renal impairment on the pharmacokinetics of pridopidine, a new drug for Huntington's disease

Aim

Pridopidine, a new oral drug for treatment of patients with motor symptoms associated with Huntington's Disease (HD) is currently under development. In steady‐state conditions, pridopidine elimination is mediated primarily through renal excretion. This study evaluated single dose and steady‐state pharmacokinetics (PK) of a daily dose of pridopidine in subjects with mild and moderate renal impairment and matched healthy subjects.

Methods

Subjects with mild renal impairment (n = 12), moderate impairment (n = 12), or their matched healthy controls (n = 25) participated in this study. Subjects received a single dose of pridopidine (45 mg) on day 1 and a multiple dose cycle of 45 mg once daily on days 5–18. Blood and urine samples were collected on days 1 and 18 for PK analysis.

Results

Mild renal impairment did not affect the PK of pridopidine whilst an increase in exposure was seen in subjects with moderate renal impairment. Subjects with moderate impairment showed reduced plasma clearance (by 44%) and had 68% higher AUC (90% CI 1.22, 2.30) and 26% higher C_max (90% CI 1.02, 1.56) values than those with normal renal function at steady‐state. Pridopidine was safe and well tolerated in healthy subjects and in subjects with mild and moderate renal impairment.

Conclusions

Mild renal impairment has no impact on exposure to pridopidine while moderately impaired renal function resulted in higher pridopidine concentrations.

Non-union site debridement increased the efficacy of rhBMP-2 in a rodent model

In our study we investigated the influence of debridement on bone healing in a rodent critical size defect model with and without rhBMP-2 in fibrin matrix. A total of 58 male Sprague-Dawley rats underwent a first surgical procedure where a femoral osteotomy was performed. In the single step group the defect remained empty and the specimens were collected 4 weeks later. A silicone spacer was implanted to inhibit bone healing within the defect in all the other groups. At 4 weeks the spacer was removed in a second operation with and without debridement of the bone ends and fibrin matrix alone or combined with 10 μg rhBMP-2 were applied. 4 weeks after the primary operation those specimens were collected. All the specimens were evaluated by μCT scans and histological analysis. Debridement of the defect significantly increased bone volume in the animals treated with rhBMP-2. In the control groups without growth factor application the effect of debridement was not significant concerning the union rate and the bone volume. In our experimental setting surgical debridement of the non-union site particularly promoted bone healing in combination with BMP-2 administration in fibrin matrix.

Investigation of Laplace barriers for arrayed electrowetting lab-on-a-chip

Partial-post Laplace barriers have been postulated as a means to allow electrowetting transport and geometrical reshaping of fluids, followed by the preservation of fluid geometry after the electrowetting voltage is removed. Reported here is the first investigation of Laplace barriers with the arrayed electrodes and splitting/merging transport functions for an electrowetting lab-on-a-chip. Laplace barriers optimized for 500 × 500 μm(2) electrodes and 78 μm channel height are shown to provide geometrical control of fluid shape down to radii of curvature of ~70 μm. The Laplace barriers increase the splitting volume error, but with proper electrical control, the average error in the split volume is reduced to 5%. Improved programmable fluid storage in droplets or reservoirs and continuous channel flow are also shown. This work confirms the potential benefits of Laplace barriers for lab-on-a-chip and also reveals the unique challenges and operation requirements for Laplace barriers in lab-on-a-chip applications.

Hot topic: apparent total-tract nutrient digestibilities measured commercially using 120-hour in vitro indigestible neutral detergent fiber as a marker are related to commercial dairy cattle performance

Measuring individual feed nutrient concentration is common practice for field dairy nutritionists. However, accurately measuring nutrient digestibility and using digestion values in total digestible nutrients models is more challenging. Our objective was to determine if in vivo apparent total-tract nutrient digestibility measured with a practical approach was related to commercial milk production parameters. Total mixed ration and fecal samples were collected from high-producing cows in pens on 39 commercial dairies and analyzed at a commercial feed and forage testing laboratory for nutrient concentration and 120-h indigestible NDF (iNDF) content using the Combs-Goeser in vitro digestion technique. The 120-h iNDF was used as an internal marker to calculate in vivo apparent nutrient digestibilities. Two samples were taken from each dairy and were separated in time by at least 3 wk. Samples were targeted to be taken within 7d of Dairy Herd Improvement (DHI) herd testing. Approved DHI testers measured individual cow milk weights as well as fat and protein concentrations. Individual cow records were averaged by pen corresponding to the total mixed ration and fecal samples. Formulated diet and dry matter intake (DMI) records for each respective pen were also collected. Mixed model regression analysis with dairy specified as a random effect was used to relate explanatory variables (diet nutrient concentrations, formulated DMI, in vivo apparent nutrient digestibilities, and fecal nutrient concentrations) to milk production measures. Dry matter intake, organic matter (OM) digestibility, fecal crude protein (CP) concentration, and fecal ether extract concentration were related to milk, energy-corrected milk, and fat yields. Milk protein concentration was related to CP digestibility, and milk protein yield was related to DMI, OM digestibility, CP digestibility, and ether extract digestibility. Although many studies have related DMI and OM digestibility to milk production under controlled experimental settings, very few have related practical in vivo measures to milk production. By documenting the practical OM digestibility relationship with milk production, nutritionists and scientists may have confidence in this approach for measuring diet performance and collecting nutritional data for commercial dairies.

Prevalence of alkane monooxygenase genes in Arctic and Antarctic hydrocarbon-contaminated and pristine soils

Abstract The prevalence of four alkane monooxygenase genotypes (Pseudomonas putida GPo1, Pp alkB; Rhodococcus sp. strain Q15, Rh alkB1 and Rh alkB2; and Acinetobacter sp. strain ADP-1, Ac alkM) in hydrocarbon-contaminated and pristine soils from the Arctic and Antarctica were determined by both culture-independent (PCR hybridization analyses) and culture-dependent (colony hybridization analyses) molecular methods, using oligonucleotide primers and DNA probes specific for each of the alk genotypes. PCR hybridization of total soil community DNA detected the rhodococcal alkB genotypes in most of the contaminated (Rh alkB1, 18/20 soils; Rh alkB2, 13/20) and many pristine soils (Rh alkB1, 9/10 soils; Rh alkB2, 7/10), while Pp alkB was generally detected in the contaminated soils (15/20) but less often in pristine soils (5/10). Ac alkM was rarely detected in the soils (1/30). The colony hybridization technique was used to determine the prevalence of each of the alk genes and determine their relative abundance in culturable cold-adapted (5 degrees C) and mesophilic populations (37 degrees C) from eight of the polar soils. The cold-adapted populations, in general, possessed relatively higher percentages of the Rh alkB genotypes (Rh alkB1, 1.9% (0.55); Rh alkB2, 2.47% (0.89)), followed by the Pp alkB (1.13% (0.50)), and then the Ac alkM (0.53% (0.36)). The Rh alkB1 genotype was clearly more prevalent in culturable cold-adapted bacteria (1.9% (0.55)) than in culturable mesophiles (0.41 (0.55)), suggesting that cold-adapted bacteria are the predominant organisms possessing this genotype. Overall, these results indicated that (i) Acinetobacter spp. are not predominant members of polar alkane degradative microbial communities, (ii) Pseudomonas spp. may become enriched in polar soils following contamination events, and (iii) Rhodococcus spp. may be the predominant alkane-degradative bacteria in both pristine and contaminated polar soils.

Long-term, high intake of vitamin C decreases size and increases quantity of liver mitochondria in Guinea-pigs

Microsomal cytochrome P450 is an important enzyme involved in drug metabolism and bioactivation in the liver. In guinea-pigs, the specific amount of cytochrome P450 depends on dietary vitamin C intake. Short-term vitamin C treatment can induce non-genomic effects on hepatocytes, such as activating mitochondrial respiration without changing cytochrome concentration. The aim of this investigation was to elucidate the long-term effects of a low or high vitamin C diet on the quantity and size of mitochondria in the hepatocytes of guinea-pigs. After 6 - 8 weeks of vitamin C feeding, the group receiving a low vitamin C content in their food (10 mg/100 g food) had significantly less mitochondria, but of a larger size, than the group receiving a high vitamin C content (680 mg/100 g food). This animal model investigation demonstrated that treatment with long-term vitamin C can induce morphological changes in the mitochondria of hepatocytes.

The PFA-100R cannot detect blood group-dependent inhibition of platelet function by eptifibatide or abciximab at therapeutic plasma concentrations

Previous investigations revealed that AB0 blood groups are associated with divergent concentrations of several coagulation factors. Concentrations of von Willebrand factor (vWF) and factor VIII are lower in individuals with blood group 0 compared to subjects with blood group A, B or AB, which might in turn result in a reduced inhibition of platelet aggregation in individuals with blood group 0. The aim of the present in vitro investigation was to elucidate the impact of AB0 blood group-dependent vWF concentrations on eptifibatide and abciximab mediated inhibition of GPIIb/IIIa function. Platelet function was measured with the platelet function analyzer PFA-100(R) at baseline and at increasing concentrations of eptifibatide and abciximab. It was stratified for blood group 0 vs A. If measured with the collagen/ADP cartridge, blood group 0 was associated with a prolonged mean baseline closure time in comparison with blood group A (94.3 +/- 14.6 s vs. 74.6 +/- 9.9 s, p = 0.007) which was paralleled by reduced concentrations of vWF and factor VIII. In contrast, no statistically significant differences in closure times (167.4 +/- 83.9 s vs. 140.1 +/- 99.0 s, p = 0.562) could be found in the presence of eptifibatide (0.1 microg/ml). Higher concentrations of abciximab (1 microg/ml) than those of eptifibatide were needed to increase the closure times in both cartridges of the PFA-100, but at this concentration of abciximab differences in closure times could not be detected most probably due to higher variability at these drug concentrations. The PFA-100(R) is not suitable for monitoring abciximab or eptifibatide within the therapeutic concentration range because the highest concentrations where the PFA-100(R) had measurable closure times of below 300 s is much too low to lead to the necessary platelet inhibition and, consequently, does not resemble the in vivo situation.