The DNP project: Two decades of impact.

ABSTRACT: Twenty years ago, pioneer Doctor of Nursing Practice (DNP) program students completed the first DNP projects. Today, DNP projects remain a requirement for graduation. This article illustrates how the DNP project can be integrated throughout the DNP curriculum to maximize effectiveness and promote the introduction, reinforcement, and evaluation of competencies in the new American Association of Colleges of Nursing Essentials.

Hydrodynamic Assembly of Astrocyte Cells in Conductive Hollow Microfibers.

The manufacturing of 3D cell scaffoldings provides advantages for modeling diseases and injuries as it enables the creation of physiologically relevant platforms. A triple-flow microfluidic device is developed to rapidly fabricate alginate/graphene hollow microfibers based on the gelation of alginate induced with CaCl2 . This five-channel microdevice actualizes continuous mild fabrication of hollow fibers under an optimized flow rate ratio of 300:200:100 µL min-1 . The polymer solution is 2.5% alginate in 0.1% graphene and a 30% polyethylene glycol solution is used as the sheath and core solutions. The biocompatibility of these conductive microfibers by encapsulating mouse astrocyte cells (C8D1A) within the scaffolds is investigated. The cells can successfully survive both the manufacturing process and prolonged encapsulation for up to 8 days, where there is between 18-53% of live cells on both the alginate microfibers and alginate/graphene microfibers. These unique 3D hollow scaffolds can significantly enhance the available surface area for nutrient transport to the cells. In addition, these conductive hollow scaffolds illustrate unique advantages such as 0.728 cm3  gr-1 porosity and two times more electrical conductivity in comparison to alginate scaffolds. The results confirm the potential of these scaffolds as a microenvironment that supports cell growth.

EXPERIMENTAL CHOLECALCIFEROL SUPPLEMENTATION IN A HERD OF MANAGED ASIAN ELEPHANTS (ELEPHAS MAXIMUS).

Vitamin D supplementation may pose a significant health risk in species where levels of deficiency, sufficiency, and toxicity have not been clearly established, and species-specific research on vitamin D supplementation should be performed. This study documented the effect of vitamin D supplementation on serum vitamin D metabolites and other analytes of Ca homeostasis in Asian elephants (Elephas maximus). Six adult Asian elephants received PO supplementation with cholecalciferol at 300 IU/kg of body weight (BW) once a week for 24 wk. Serum was analyzed every 4 wk for 25-hydroxyvitamin D2/D3 [25(OH)D]; 24,25-dihydroxyvitamin D2/D3 [24,25(OH)2D]; 1,25-dihydroxyvitamin D [1,25(OH)2D]; parathyroid hormone (PTH); total Ca; ionized Ca (iCa); P; and Mg. After the supplement was discontinued, serum 25(OH)D2/D3 was measured every 4 wk until levels returned to baseline. At the start of the study, the average serum 25(OH)D3 was nondetectable (<1.5 ng/ml). With cholecalciferol supplementation, 25(OH)D3 increased at an average rate of 2.26 ng/ml per month and reached an average concentration of 12.9 ± 3.46 ng/ml at 24 wk. Both 24,25(OH)2D3 and 1,25(OH)2D increased over time with supplementation from an average of <1.5 to 12.9 ng/ml and from 9.67 to 36.4 pg/ml, respectively. PTH, iCa, Ca, P, and Mg remained within reported normal ranges throughout supplementation. After the supplement was discontinued, serum 25(OH)D3 demonstrated a slow decline to baseline, taking an average of 48 wk. Elephants demonstrated significant individual variation in response to supplementation and subsequent return to baseline. Supplementation of Asian elephants with a weekly dose of 300 IU/kg BW cholecalciferol for 24 wk appears to be effective and safe. Additional clinical studies would be necessary to investigate the safety of other routes of administration, dosages, and duration of vitamin D supplementation, as well as associated health benefits.

Using unfolding case scenarios to promote clinical reasoning for nurse practitioner students.

ABSTRACT: This article describes how an unfolding case study can be used to promote the development of clinical reasoning through students' self-reported perceptions, although at the same time facilitating collaboration among providers from various specialties. An unfolding case (evolving case) provides sequential information about a patient's illness trajectory as they experience the illness and related symptomology. An unfolding case study was implemented during a college skills laboratory immersion experience for 33 nurse practitioner (NP) students who were in their final year of the NP program. Students were invited per email to complete a confidential REDCap survey after the case presentation and discussion. Twenty-three students completed the survey. More than half of the students (52%) stated the review of the unfolding case offered "significant learning value" and 78% rated the unfolding case as being "very to extremely" helpful in creating opportunities for critical thinking and engagement in clinical reasoning. Implementing unfolding case studies in NP student program curricula promotes critical thinking, clinical reasoning, and allows opportunities to engage in interprofessional collaboration.

Cutaneous concentrations of 7-dehydrocholesterol in Hoffmann's two-toed sloths (Choloepus hoffmanni) in managed care.

Hoffmann's two-toed sloths (Choloepus hoffmanni) are unique animals popular in zoological settings. The role of vitamin D in the maintenance of calcium homeostasis in this species is unexplored, although disorders of calcium homeostasis have been reported in managed sloths, including urolithiasis and soft tissue mineralization. This study assessed cutaneous concentrations of 7-dehydrocholesterol (7-DHC) in nine indoor-housed Hoffmann's two-toed sloths, as a means of evaluating the potential for cutaneous photobiosynthesis of vitamin D3 . Samples were obtained from both abdominal and lumbar regions of the skin to assess for regional variation in 7-DHC concentration. The average concentration of 7-DHC in the sloth skin was low (0.197 ± 0.02 nmol/cm2 ). Location had a significant effect on 7-DHC level only when concentrations were expressed based on the wet weight of the sample (ng/g), but levels were similar when values were normalized to biopsy surface area (nmol/cm2 ).

The effect of long-acting injectable antipsychotic medications compared with oral antipsychotic medications among people with schizophrenia: A systematic review and meta-analysis.

Long-acting injectable (LAI) antipsychotic medications may be an important modality of reducing costs, improving symptoms, and fostering quality of life outcomes for those with schizophrenia. Our objective was to systematically review and conduct a meta-analysis of the effectiveness of LAIs compared with oral antipsychotics on medication adherence, symptom remission/relapse, rehospitalization, outpatient visits, emergency department visits, healthcare costs, and social functioning. We performed a systematic search of PsycInfo, CINAHL, PubMed, and Scopus databases to examine studies meeting inclusion criteria prior to August 30th, 2020. Randomized controlled trials, retrospective studies, prospective studies among people with schizophrenia with at least 6-month follow-up data were obtained. Overall effect sizes and associated 95% confidence intervals (CI) were estimated with random-effects modeling. We found 75 articles meeting our inclusion criteria, including 341 730 individuals with schizophrenia. Systematic review results indicated that LAIs compared with orals improved medication adherence (25/29 studies), symptom remission/relapse (10/18 studies), rehospitalizations (26/49 studies), emergency department visits (9/17 studies), medical costs (11/15 studies), and social functioning (5/9 studies); however, LAIs also increased outpatient visits (7/16 studies) and pharmacy costs (10/10 studies). Meta-analytic results of studies with similar outcome measures did not find differences between LAIs and orals in respect to outcomes, except lowering emergency department visits and increasing pharmacy costs. The differences between the results of the narrative synthesis and the meta-analyses were possibly because of the low availability of studies with similar outcomes in the pooled analyses. Our overall results suggest that LAIs are at least comparable to orals in supporting important healthcare outcomes for those with schizophrenia. These findings support clinical practice in encouraging providers to prescribe LAIs when indicated.

VITAMIN D STATUS OF INDOOR-HOUSED HOFFMANN'S TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI): A PILOT STUDY.

Disorders of calcium homeostasis have been reported with some frequency in two-toed sloths, yet little investigation has been performed on vitamin D and mineral metabolism in these species. This study evaluates biomarkers involved in vitamin D and calcium metabolism in a group of nine managed Hoffmann's two-toed sloths (Choloepus hoffmanni), correlated with diet analysis. Serum was analyzed for both vitamin D2 and D3 metabolites, minerals (calcium [Ca], phosphorus [P], and magnesium [Mg]), parathyroid hormone (PTH), and ionized calcium (iCa). The diet was analyzed for proximate nutrients, minerals and vitamins D2 and D3, and feed intake was estimated. Average values reported for D3 metabolites, including 25(OH)D3, 1,25(OH)2D3, and 24,25(OH)2D3, were 25.1 ng/ml, 52.23 pg/ml, and 7.65 ng/ml, respectively. Average PTH was 0.22 pmol/L while average iCa was 1.46 mmol/L. Values reported for Ca, P, Mg were within expected ranges. Dietary concentration of D3 was 6.7 ng/g and the average daily intake per sloth was 113.7 IU/kg body weight. No detectable levels of vitamin D2 metabolites 25(OH)D2, 1,25(OH)2D2, or 24,25(OH)2D2 were found in the diet or serum. These data will serve as a starting point for future investigations into the vitamin D metabolism and calcium homeostasis of two-toed sloths to improve the health in managed settings.

Adapting clinical experiences during a pandemic: One college of nursing's approach.

ABSTRACT: Graduate level nursing programs are having increasing difficulty obtaining clinical sites for their students. Nurse practitioner (NP) students need a minimum of 500 direct care hours in addition to indirect hours. Simulation experiences may not be used as direct patient care hours for NP students, but telehealth experiences may be used if the focus is on obtaining similar competencies to what would be acquired with face-to-face patient experiences. One college of nursing adapted several opportunities for NP students to acquire indirect clinical experiences and specific NP competencies during the coronavirus (COVID-19) pandemic. Several different clinically focused teaching methodologies were planned and implemented. These varied by NP specialty track and included complex case analyses, virtual (Zoom) rounds, well-child cases, and objective structured clinical examinations. These adapted clinical experiences are effective methods of helping students acquire clinical competencies and skills; however, they bring their own challenges. Post-COVID may be a time of new beginnings, moving nursing education forward on finding new and better ways to ensure that students acquire clinical competencies. What the new normal will be for nursing education is yet to be determined, but nursing education will likely never return to where we were before the pandemic.

Strengthening the impact of Doctor of Nursing Practice projects in education and clinical practice.

ABSTRACT: The significance and value of Doctor of Nursing Practice (DNP) projects can be potentiated by collaboration between educators and practice leaders and when students build on previous DNP projects, as demonstrated in this article. Projects can have a longstanding financial, quality, and outcome impact, helping demonstrate the worth and efficacy of the DNP degree.

Vitamin D Content in Milk of the Rhesus Monkey.

OBJECTIVE: Milk is the first and continued source of ingested Vitamin D. Extensive studies have been carried out in humans measuring Vitamin D in lactating mothers but to date few values have been obtained for milk of non-human primates and none for rhesus monkeys. Consequently. we have determined Vitamin D and antirachitic activity (ARA) in milk samples obtained from 21 rhesus monkeys. METHODS: Lactating dams were sampled by hand-stripping. 25(OH)D2, Vitamin D2, 25(OH)D3, Vitamin D3 and ARA were assessed in foremilk using LC-MS/MS techniques. RESULTS: 25(OH)D2 and Vitamin D2 were below detectible limits (<0.5 ng/g), 25(OH) D3 =4.2 ± 1.8 ng/ml, Vitamin D3 = 6.1 ± 3.1 ng/ml and ARA = 1080 ± 480 IU/L. CONCLUSION: This is the first report of content of Vitamin D and ARA activity in foremilk of the rhesus monkey and can serve as a reference for future studies.

Vitamin D status in cats with cardiomyopathy.

BACKGROUND: Low vitamin D concentrations have been associated with advanced heart disease and poorer outcomes in people and dogs. Vitamin D status typically is assessed by serum 25(OH)D concentration. However, cats also produce notable amounts of a C-3 epimer of 25(OH)D (3-epi). HYPOTHESIS/OBJECTIVES: Determine if vitamin D status, estimated by 25(OH)D3 alone or combined with 3-epi (summation vitD), is lower in cats with cardiomyopathy (CM) compared to clinically normal (N) cats and if indicators of disease severity are associated with vitamin D status. ANIMALS: Privately owned cats, 44 with CM and 56 N. METHODS: Cross-sectional observational study using clinical and echocardiographic findings, diet history, and serum 25(OH)D3 and 3-epi measurements. RESULTS: Cat age was negatively related to vitamin D status. Summation vitD was lower in CM cats (median = 47.1 ng/mL) compared to N cats (median = 58.65 ng/mL) both before (P = .03) and after (P = .04) accounting for age. However, 25(OH)D3 became nonsignificant between CM and N cats after age was included. Summation vitD was related positively to survival time and fractional shortening (FS), but negatively to left atrial enlargement (LAE) severity, both before and after accounting for age. For 25(OH)D3 alone, only survival time and FS remained significant after including age. CONCLUSIONS AND CLINICAL IMPORTANCE: We report 25(OH)D3 and 3-epi concentrations in CM and N cats. Age had an important (negative) relationship to vitamin D status. After accounting for age, summation vitD was lower in CM cats. Vitamin D status was related positively to survival time and FS, but negatively to LAE severity.

THE VITAMIN D STATUS OF ASIAN ELEPHANTS (ELEPHAS MAXIMUS) MANAGED IN A NORTHERN TEMPERATE CLIMATE.

Knowledge about the normal metabolism and involvement of vitamin D in elephant calcium homeostasis is essential to understanding the possible role of vitamin D in Asian elephant (Elephas maximus) health, as well as to informing accurate diet formulation. This study provides an evaluation of analytes involved in vitamin D metabolism, in conjunction with dietary intake and ultraviolet light (UV) exposure, in Asian elephants managed in a northern temperate climate. Once monthly, for a total of 12 mo, serum from six adult Asian elephants was analyzed for 25-hydroxyvitamin D [25(OH)D], 24,25-dihydroxyvitamin D [24,25(OH)2D], 1,25-dihydroxyvitamin D [1,25(OH)2D], parathyroid hormone (PTH), total calcium (Ca), ionized calcium (iCa), phosphorus (P), and magnesium (Mg). The diet was analyzed monthly for vitamin D, Ca, and P. Monthly average vitamin D-weighted UV daily sums were determined to gauge average UV light exposure within the vitamin D action spectrum. No serum or diet parameters were affected by time or season. Average serum 25(OH)D2 was 7.02 ± 0.85 ng/ml. 25(OH)D3 levels were nondetectable in all samples despite supplementation of the diet with recommended levels of vitamin D3, and UV exposure was at sufficient levels for cutaneous vitamin D synthesis for 6 mo of the year. Levels of 24,25(OH)2D averaged 31.7% higher than 25(OH)D, and average 1,25(OH)2D2 was 11.24 ± 1.04 pg/ml. Values for PTH, Ca, iCa, P, and Mg were within expected ranges for Asian elephants. The information gained from this research expands the knowledge base for these analytes, evaluates 24,25-dihydroxyvitamin D for the first time, and provides new information regarding vitamin D metabolism and test interpretation in the Asian elephant.

EVALUATION OF 25-HYDROXYVITAMIN D IN HOFFMANN'S TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI) USING DRIED BLOOD SPOTS ANALYZED BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY.

Although biochemical analytes have typically been measured using serum or whole blood samples, an increasing number of assays are validated for measurement of analytes from dried blood spots (DBS) on filter paper. DBS techniques are minimally invasive, require only a small sample volume, and simplify processing, storage, and shipment of samples. These qualities make DBS-based assays ideal for sampling of wildlife species in both captive and field settings. In this study, a liquid chromatography-tandem mass spectrometry assay was evaluated for measurement of 25-hydroxyvitamin D in sloths. Paired serum and DBS samples were collected from nine healthy captive Hoffmann's two-toed sloths (Choloepus hoffmanni). Statistical analysis using Passing-Bablok regression analysis, Bland-Altman plots, and the Wilcoxon signed-rank tests found good agreement between 25-hydroxyvitamin D3 measurements in serum and DBS samples. Constant and proportional bias were absent. Results from this study support the use of DBS samples for the evaluation of vitamin D status in Hoffmann's two-toed sloths and provide a foundation for further studies to validate this technique.

Inferior lumbar triangle hernia with incarceration.

Lumbar hernia is a rare condition in which intra or extraperitoneal tissue protrudes through a defect in the posterolateral region of the flank. Incarceration is uncommon but represents a surgical emergency when present. A 54-year-old-male presented to the ED after sudden onset left flank pain after coughing. He was in significant distress secondary to pain and vomiting, and his physical exam revealed a tender mass in his left lateral lumbar region near the site of a previous stab wound. Bedside ultrasound revealed a fluid-filled structure, and CT scan demonstrated herniation of small bowel though the inferior lumbar triangle with associated small bowel obstruction. The patient underwent emergent surgical reduction with mesh repair and recovered uneventfully. Incarcerated lumbar hernia represents a rare diagnosis that may not be at the forefront of most practitioners' differential diagnoses. CT scan is useful to distinguish hernia from solid mass, abscess, or other pathology, while bedside ultrasound may prompt an attempt at immediate reduction. The presence of incarcerated bowel or obstruction warrants immediate surgical consultation.

Obesity Decreases Hepatic 25-Hydroxylase Activity Causing Low Serum 25-Hydroxyvitamin D.

Normal vitamin D homeostasis is critical for optimal health; nevertheless, vitamin D deficiency is a worldwide public health problem. Vitamin D insufficiency is most commonly due to inadequate cutaneous synthesis of cholecalciferol and/or insufficient intake of vitamin D, but can also arise as a consequence of pathological states such as obesity. Serum concentrations of 25(OH)D (calcidiol) are low in obesity, and fail to increase appropriately after vitamin D supplementation. Although sequestration of vitamin D in adipose tissues or dilution of ingested or cutaneously synthesized vitamin D in the large fat mass of obese patients has been proposed to explain these findings, here we investigate the alternative mechanism that reduced capacity to convert parent vitamin D to 25(OH)D due to decreased expression of CYP2R1, the principal hepatic vitamin D 25-hydroxylase. To test this hypothesis, we isolated livers from female mice of 6 to 24 weeks of age, weaned onto either a normal chow diet or a high-fat diet, and determined the abundance of Cyp2r1 mRNA using digital droplet-quantitative PCR. We observed a significant (p < 0.001) decrease in Cyp2r1 mRNA in the liver of high-fat diet-fed mice relative to lean-chow-fed female mice. Moreover, there was a significant (p < 0.01) relationship between levels of Cyp2r1 mRNA and serum 25(OH)D concentrations as well as between Cyp2R1 mRNA and the ratio of circulating 25(OH)D3 to cholecalciferol (p < 0.0001). Using linear regression we determined a curve with 25(OH)D3/cholecalciferol versus normalized Cyp2R1 mRNA abundance with an R2 value of 0.85. Finally, we performed ex vivo activity assays of isolated livers and found that obese mice generated significantly less 25(OH)D3 than lean mice (p < 0.05). Our findings indicate that expression of CYP2R1 is reduced in obesity and accounts in part for the decreased circulating 25(OH)D. © 2019 American Society for Bone and Mineral Research.

The effects of maternal dietary supplementation of cholecalciferol (vitamin D3) and 25(OH)D3 on sow and progeny performance.

A total of 69 sows (DNA Line 200 × 400) and their progeny were used to determine if feeding a combination of vitamin D3 and 25(OH)D3 influences neonatal and sow vitamin D status, muscle fiber morphometrics at birth and weaning, and subsequent growth performance. Within 3 d of breeding, sows were allotted to one of three dietary treatments fortified with 1,500 IU/kg vitamin D3 (CON), 500 IU/kg vitamin D3 + 25 µg/kg 25(OH)D3 (DL), or 1,500 IU/kg vitamin D3 + 50 µg/kg 25(OH)D3 (DH). When pigs were sacrificed at birth, there were no treatment effects for all fiber morphometric measures (P > 0.170), except primary fiber number and the ratio of secondary to primary muscle fibers (P < 0.016). Pigs from CON fed sows had fewer primary fibers than pigs from sows fed the DH treatment (P = 0.014), with pigs from sows fed DL treatment not differing from either (P > 0.104). Pigs from CON and DL fed sows had a greater secondary to primary muscle fiber ratio compared to pigs from DH sows (P < 0.022) but did not differ from each other (P = 0.994). There were treatment × time interactions for all sow and pig serum metabolites (P < 0.001). Therefore, treatment means were compared within the time period. At all time periods, sow serum 25(OH)D3 concentrations differed for all treatments with the magnitude of difference largest at weaning (P < 0.011), where serum 25(OH)D3 concentration was always the greatest when sows were fed the DH diet. At birth, piglets from DH fed sows had greater serum 25(OH)D3 concentrations than piglets from sows fed the DL treatment (P = 0.003), with piglets from sows fed CON treatment not differing from either (P > 0.061). At weaning, serum concentrations of 25(OH)D3 in piglets from all sow treatments were different (P < 0.001), with the greatest concentration in piglets from DH sows, followed by CON, and followed by DL. There were no treatment × time interactions for any of the metabolites measured in milk and no treatment or time main effects for 24,25(OH)2D3 concentration (P > 0.068). Colostrum collected within 12 h of parturition contained less (P = 0.001) 25(OH)D3 than milk collected on day 21 of lactation. Regardless of time, concentrations of 25(OH)D3 in milk were different (P < 0.030), with the largest 25(OH)D3 concentration from DH fed sows, followed by DL, and then CON. In conclusion, combining vitamin D3 and 25(OH)D3 in the maternal diet improves the vitamin D status of the dam and progeny and it increases primary muscle fiber number at birth.

SEASONAL VARIATION OF SERUM 25-HYDROXY-VITAMIN D IN TWO CAPTIVE EASTERN BLACK RHINOCEROS ( DICEROS BICORNIS MICHAELI) HOUSED IN A NORTH AMERICAN ZOO.

Black rhinoceros ( Diceros bicornis spp.) are critically endangered species, with less than 65 individual animals housed in captivity within Association of Zoos and Aquariums-accredited zoos within the United States, and an estimated 5,500 individual animals of all subspecies surviving in the wild. Previously published reference values for circulating vitamin D3 (25OHD3; 55.7 ± 34.2 ng/ml) were based upon samples from free-ranging black rhinoceros in Africa. Recent research in human medicine has highlighted the importance of subclinical vitamin D deficiency, with links to increased risks for developing various health conditions. Serum samples collected opportunistically from two captive Eastern black rhinoceros ( Diceros bicornis michaeli) housed with seasonal access outdoors in a North American zoo were tested for 25-hydroxy-vitamin D (25OHD) levels over a 3-yr period. A commercially prepared pelleted diet containing vitamin D3 was fed to both rhinos. This study correlates environmental ultraviolet (UV) index, dietary supplementation, and seasonal serum 25OHD levels to compare with known 25OHD3 levels in free-ranging African black rhinoceros. Results in these two individuals suggest that D. bicornis spp. are dependent upon sunlight or UVB for measurable circulating 25OHD, and that current vitamin D3 supplementation levels may have little effect for Diceros spp. in human care housed in northern latitudes.

Sun exposure in pigs increases the vitamin D nutritional quality of pork.

There is a high prevalence of vitamin D insufficiency and deficiency worldwide likely because of both limited sun-exposure and inadequate dietary intake. Meat, including pork, is not typically considered a dietary source of vitamin D, possibly because of management practices that raise pigs in confinement. This experiment determined the vitamin D content of loin and subcutaneous adipose tissue in sun-exposed finisher pigs. Two separate groups of pigs were used. The first group (28 white Landrace-Duroc) was assigned at random to either sunlight exposure (SUN) in spring and summer or confinement per standard practice (Control). The second (24 Yorkshire-Duroc-Landrace) underwent the same exposure protocol but was exposed in summer and fall or assigned to control (Control). A subsample of five SUN and four Control pigs, matched for weight and body condition score, was selected for slaughter from each group. Pigs (n = 10 SUN, n = 8 Control) had blood drawn for analysis of 25(OH)D3 concentration before/after sun exposure or control, and tissue samples were taken at slaughter for analysis of tissue vitamin D3 and 25(OH)D3 concentration. Three random samples from a single loin chop and surrounding adipose were collected and analyzed. Serum concentrations of 25(OH)D3 did not differ (P≥0.376) between treatments prior to sun exposure in either group, but was increased (time*treatment interaction, P<0.001) with SUN exposure. Total vitamin D content (D3 plus 25(OH)D3) of loin tissue was increased (P < 0.001) with sun exposure and averaged 0.997±0.094 µg/100g and 0.348±0.027 µg/100g for sun and control pigs, respectively. While exposure to sunlight increased (P = 0.003) tissue content of 25(OH) D in subcutaneous adipose tissue, vitamin D3 content was similar between treatments (P = 0.56). Sunlight exposure in pigs increased the vitamin D content of loin, and may provide an additional source of dietary vitamin D.

Simplified 25-Hydroxyvitamin D Standardization and Optimization in Dried Blood Spots by LC-MS/MS.

Previous studies have assessed vitamin D status based on the 25-hydroxyvitamin D [25(OH)D] concentration measured in samples from dried blood spots (DBSs). In 40 individuals participating in a clinical study, we compared 25(OH)D levels measured from DBSs and in serum using an LC-MS/MS reference procedure in collaboration with the Vitamin D Standardization Program. The main objective was to simplify and optimize current methods to produce an assay that can be used as a screening tool for 25(OH)D concentration assessment without derivatization. The DBS 25(OH)D levels, compared to serum concentrations, were found to have 101% accuracy overall, and the correlation coefficient (r) was 0.83 (P < 0.0001), with a significant linear relationship. Free 25(OH)D and vitamin D binding protein (VDBP) were assessed in the serum samples for potential correlations to the DBS calculations: the levels of free 25(OH)D had moderate to strong correlation to DBS and serum concentrations, with r values of 0.67 (P < 0.0001) and 0.76 (P < 0.0001), respectively. VDBP and hematocrit had no significant correlation to either DBS or serum sample types, with r values <0.1. In conclusion, the use of two DBSs and an increase in DBS sample size improved overall sample representation without the need for derivatization, and produced an accurate and robust method that can be used to screen 25(OH)D levels.

Prostatic compensation of the vitamin D axis in African American men.

BACKGROUND. African American (AA) men are disproportionately affected by both prostate cancer (PCa) and vitamin D deficiency compared with European American (EA) men. Vitamin D deficiency is linked to increased PCa aggressiveness and mortality. Therefore, it has been hypothesized that vitamin D deficiency may contribute to the PCa disparity between AA and EA men. METHODS. We studied a cross sectional group of 60 PCa patients (AA, n = 31; EA, n = 29) who underwent radical prostatectomy. Vitamin D metabolites 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) were measured in the serum and tissue by uHPLC-MS-MS. Tissue was laser capture microdissected, and gene expression was quantified by microarray. DNA isolated from whole blood was genotyped for West African ancestry markers and vitamin D-related SNPs. RESULTS. Serum concentrations of 25(OH)D were lower in AAs, but concentrations of 1,25(OH)2D in the prostate tissue were higher compared with EAs. Expression of the vitamin D receptor was higher in prostate tissue from AAs. Expression of the extracellular receptor of vitamin D binding protein, LRP2, was positively associated with West African ancestry and inversely associated with tissue 25(OH)D concentrations in AAs. CONCLUSIONS. The relationships between vitamin D binding protein LRP2 and vitamin D metabolites suggest that the prohormone is actively transported into the prostate, followed by intraprostatic conversion to the active hormone, rather than passive diffusion. These findings support the presence of a compensatory response in prostate tissue to vitamin D deficiency in AAs and reveal a previously unknown complexity involving tissue distribution of vitamin D metabolites. FUNDING. Department of Defense Prostate Cancer Research Program Idea Award for Disparities Research PC121923 (LN and RK) and the NIH 1R01MD007105 (RK).