Final Measurement of the ^{235}U Antineutrino Energy Spectrum with the PROSPECT-I Detector at HFIR

This Letter reports one of the most precise measurements to date of the antineutrino spectrum from a purely ^{235}U-fueled reactor, made with the final dataset from the PROSPECT-I detector at the High Flux Isotope Reactor. By extracting information from previously unused detector segments, this analysis effectively doubles the statistics of the previous PROSPECT measurement. The reconstructed energy spectrum is unfolded into antineutrino energy and compared with both the Huber-Mueller model and a spectrum from a commercial reactor burning multiple fuel isotopes. A local excess over the model is observed in the 5-7 MeV energy region. Comparison of the PROSPECT results with those from commercial reactors provides new constraints on the origin of this excess, disfavoring at 2.0 and 3.7 standard deviations the hypotheses that antineutrinos from ^{235}U are solely responsible and noncontributors to the excess observed at commercial reactors, respectively.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

Joint Measurement of the ^{235}U Antineutrino Spectrum by PROSPECT and STEREO

The PROSPECT and STEREO collaborations present a combined measurement of the pure ^{235}U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with χ^{2}/ndf=24.1/21, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This ν[over ¯]_{e} energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model χ^{2} value is improved, corresponding to a 2.4σ significance.

A systematic literature review on the effects of mycotoxin exposure on insects and on mycotoxin accumulation and biotransformation

Novel protein sources for animal feed are needed, and the use of insects as feed ingredient is explored. The insect production sector offers opportunities for a circular and sustainable approach to feed production by upgrading waste or side streams into high-quality proteins. However, potential food or feed safety issues should be studied in advance. Mycotoxins, such as aflatoxin B1, are natural contaminants commonly found in agricultural crops and have proven to be detrimental to the agricultural industry, livestock, and human health. This systematic review aims to provide a comprehensive overview of the published evidence on effects of mycotoxin exposure on insect growth and survival, mycotoxin accumulation within the insect body, and metabolization of various mycotoxins by insects. The review includes 54 scientific articles published in the past 55 years, in total covering 32 insect species. The main findings are the following: (1) Insects of the order Coleoptera show lower mortality after exposure to aflatoxin B1 when compared to Lepidoptera and Diptera; (2) effects of mycotoxins on larval growth and survival are less detrimental in later larval stages; (3) accumulation of mycotoxins was low in most insect species; (4) mycotoxins are metabolized within the insect body, the degree of which depends on the particular mycotoxin and insect species; (5) cytochrome P450s are the main family of enzymes involved in biotransformation of mycotoxins in some insect species. Results of this review support an optimistic outlook for the use of mycotoxin-contaminated waste streams as substrate for insect rearing.

Ruminal transcript abundance of the centromere-associated protein E gene may influence residual feed intake in beef steers

A better understanding regarding the mechanisms by which the rumen processes feed may assist us in identifying animals with superior feed efficiency. Studies to evaluate the gene expression of rumen tissue have previously been performed to analyze their relationship with feed efficiency. Continuing this research is critical to determine whether the expression of the genes identified is associated with feed efficiency in additional populations of beef cattle to ensure that they are robust across breed and environment. A previous rumen-transcriptome study on Hereford × Angus steers identified 122 differentially expressed genes (P_FDR  < 0.05) associated with residual feed intake (RFI), a measure of feed efficiency. The purpose of our study was to test the most divergent, up- and down-regulated genes in the rumen tissue of an unrelated population of Hereford × Angus steers that included two contemporary groups. A total of 13 genes were evaluated by quantitative real-time PCR. The centromere-associated protein E (CENPE) gene was expressed in lower concentrations in the rumen epithelium of steers in the more efficient (low RFI) group in both contemporary groups of animals, which was the same as the previous study. In addition, CENPE, a gene involved in chromosome alignment during mitosis, has also been associated with growth traits in cattle and pigs. There was no relationship between the expression of the other 12 genes tested with RFI in the population of steers in this study, which illustrates the importance of validating gene expression data in additional populations.

Comparing Shared Patient Networks Across Payers

BACKGROUND

Measuring care coordination in administrative data facilitates important research to improve care quality.

OBJECTIVE

To compare shared patient networks constructed from administrative claims data across multiple payers.

DESIGN

Social network analysis of pooled cross sections of physicians treating prevalent colorectal cancer patients between 2003 and 2013.

PARTICIPANTS

Surgeons, medical oncologists, and radiation oncologists identified from North Carolina Central Cancer Registry data linked to Medicare claims (N = 1735) and private insurance claims (N = 1321).

MAIN MEASURES

Provider-level measures included the number of patients treated, the number of providers with whom they share patients (by specialty), the extent of patient sharing with each specialty, and network centrality. Network-level measures included the number of providers and shared patients, the density of shared-patient relationships among providers, and the size and composition of clusters of providers with a high level of patient sharing.

RESULTS

For 24.5% of providers, total patient volume rank differed by at least one quintile group between payers. Medicare claims missed 14.6% of all shared patient relationships between providers, but captured a greater number of patient-sharing relationships per provider compared with the private insurance database, even after controlling for the total number of patients (27.242 vs 26.044, p < 0.001). Providers in the private network shared a higher fraction of patients with other providers (0.226 vs 0.127, p < 0.001) compared to the Medicare network. Clustering coefficients for providers, weighted betweenness, and eigenvector centrality varied greatly across payers. Network differences led to some clusters of providers that existed in the combined network not being detected in Medicare alone.

CONCLUSION

Many features of shared patient networks constructed from a single-payer database differed from similar networks constructed from other payers' data. Depending on a study's goals, shortcomings of single-payer networks should be considered when using claims data to draw conclusions about provider behavior.

Effects of excess metabolizable protein on ovarian function and circulating amino acids of beef cows: 1. Excessive supply from corn gluten meal or soybean meal

In the dairy industry, excess dietary CP is consistently correlated with decreased conception rates. However, the source from which excess CP is derived and how it affects reproductive function in beef cattle is largely undefined. The objective of this experiment was to determine the effects of feeding excess metabolizable protein (MP) from feedstuffs differing in rumen degradability on ovulatory follicular dynamics, subsequent corpus luteum (CL) development, steroid hormone production and circulating amino acids (AA) in beef cows. Non-pregnant, non-lactating mature beef cows (n=18) were assigned to 1 of 2 isonitrogenous diets (150% of MP requirements) designed to maintain similar BW and body condition score (BCS) between treatments. Diets consisted of ad libitum corn stalks supplemented with corn gluten meal (moderate rumen undegradable protein (RUP); CGM) or soybean meal (low RUP; SBM). After a 20-day supplement adaptation period, cows were synchronized for ovulation. After 10 days of synchronization, gonadotropin releasing hormone (GnRH) was administered to reset ovarian follicular growth. Starting at GnRH administration and daily thereafter until spontaneous ovulation, transrectal ultrasonography was used to diagram ovarian follicular growth, and blood samples were collected for hormone, metabolite and AA analyses. After 7 days of visual detection of estrus, CL size was determined via ultrasound. Data were analyzed using the MIXED procedures of SAS. As designed, cow BW and BCS were not different (P⩾0.33). Ovulatory follicular wavelength, antral follicle count, ovulatory follicle size at dominance and duration of dominance were not different (P>0.13) between treatments. Cows supplemented with CGM had greater post-dominance ovulatory follicle growth, larger dominant follicles at spontaneous luteolysis, shorter proestrus, and larger ovulatory follicles (P⩽0.03) than SBM cows. No differences (P⩾0.44) in peak estradiol, ratio of estradiol to ovulatory follicle volume, or plasma urea nitrogen were observed. While CL volume and the ratio of progesterone to CL volume were not affected by treatment (P⩾0.24), CGM treated cows tended to have decreased (P=0.07) circulating progesterone 7 days post-estrus compared with SBM cows. Although total circulating plasma AA concentration did not differ (P=0.70) between treatments, CGM cows had greater phenylalanine (P=0.03) and tended to have greater leucine concentrations (P=0.07) than SBM cows. In summary, these data illustrate that excess MP when supplemented to cows consuming a low quality forage may differentially impact ovarian function depending on ruminal degradability of the protein source.

Ruminal expression of the NQO1, RGS5, and ACAT1 genes may be indicators of feed efficiency in beef steers

Ruminal genes differentially expressed in crossbred beef steers from USMARC with variation in gain and feed intake were identified in a previous study. Several of the genes identified with expression patterns differing between animals with high gain-low feed intake and low gain-high feed intake were evaluated in a separate, unrelated population of Angus × Hereford beef steers from the University of Wyoming that was classified to differ in residual feed intake (RFI). Of the 17 genes tested, two were differentially expressed by RFI class in the Angus × Hereford animals. These genes included NAD(P)H dehydrogenase, quinone 1 (NQO1; P = 0.0009) and regulator of G-protein signaling 5 (RGS5; P = 0.01). A third gene, acetyl-CoA acetyltransferase 1 (ACAT1; P = 0.06), displayed a trend toward association with RFI. These data suggest that some of the genes identified in a previous rumen transcriptome discovery study may have utility for identifying or selecting for animals with superior feed efficiency phenotypes across cattle breeds and populations.

Small intestinal growth measures are correlated with feed efficiency in market weight cattle, despite minimal effects of maternal nutrition during early to midgestation

We hypothesized that gestational nutrition would affect calf feed efficiency and small intestinal biology, which would be correlated with feed efficiency. Multiparous beef cows (n = 36) were individually fed 1 of 3 diets from d 45 to 185 of gestation: native grass hay and supplement to meet NRC recommendations (control [CON]), 70% of CON NEm (nutrient restricted [NR]), or a NR diet with a RUP supplement (NR+RUP) to provide similar essential AA as CON. After d 185 of gestation, cows were managed as a single group, and calf individual feed intake was measured with the GrowSafe System during finishing. At slaughter, the small intestine was dissected and sampled. Data were analyzed with calf sex as a block. There was no effect (P ≥ 0.33) of maternal treatment on residual feed intake, G:F, DMI, ADG, or final BW. Small intestinal mass did not differ (P ≥ 0.38) among treatments, although calf small intestinal length tended (P = 0.07) to be greater for NR than NR+RUP. There were no differences (P ≥ 0.20) in calf small intestinal density or jejunal cellularity, proliferation, or vascularity among treatments. Jejunal soluble guanylate cyclase mRNA was greater (P < 0.03) for NR+RUP than CON and NR. Residual feed intake was positively correlated (P ≤ 0.09) with small intestinal mass and relative mass and jejunal RNA content but was negatively correlated (P ≤ 0.09) with jejunal mucosal density and DNA concentration. Gain:feed was positively correlated (P ≤ 0.09) with jejunal mucosal density, DNA, protein, and total cells and was negatively correlated (P ≤ 0.05) with small intestinal relative mass, jejunal RNA, and RNA:DNA. Dry matter intake was positively correlated (P ≤ 0.09) with small intestinal mass, relative mass, length, and density as well as jejunal DNA and protein content, total cells, total vascularity, and kinase insert domain receptor and endothelial nitric oxide synthase 3 mRNA and was negatively correlated (P = 0.02) with relative small intestinal length. In this study, calf performance and efficiency during finishing as well as most measures of small intestinal growth were not affected by maternal nutrient restriction during early and midgestation. Results indicate that offspring small intestinal gene expression may be affected by gestational nutrition even when apparent tissue growth is unchanged. Furthermore, small intestinal size and growth may explain some variation in efficiency of nutrient utilization in feedlot cattle.

Dietary selenium and nutritional plane alter specific aspects of maternal endocrine status during pregnancy and lactation

Objectives were to examine effects of selenium (Se) supply and maternal nutritional plane during gestation on placental size at term and maternal endocrine profiles throughout gestation and early lactation. Ewe lambs (n = 84) were allocated to treatments that included Se supply of adequate Se (ASe; 11.5 μg/kg BW) or high Se (HSe; 77 μg/kg BW) initiated at breeding and nutritional plane of 60% (RES), 100% (CON), or 140% (EXC) of requirements beginning on day 40 of gestation. At parturition, lambs were removed from their dams, and ewes were transitioned to a common diet that met requirements of lactation. Blood samples were taken from a subset of ewes (n = 42) throughout gestation, during parturition, and throughout lactation to determine hormone concentrations. Cotyledon number was reduced (P = 0.03) in RES and EXC ewes compared with CON ewes. Placental delivery time tended (P = 0.08) to be shorter in HSe ewes than in ASe ewes, whereas placental delivery time was longer (P = 0.02) in RES ewes than in CON and EXC ewes. During gestation, maternal progesterone, estradiol-17β, and GH were increased (P < 0.05) in RES ewes and decreased (P < 0.05) in EXC ewes compared with CON ewes. In contrast, maternal cortisol, IGF-I, prolactin, triiodothyronine, and thyroxine were decreased in RES ewes and increased in EXC ewes compared with CON ewes during gestation. Selenium supply did not alter maternal hormone profiles during gestation. During parturition and lactation, maternal hormone concentrations were influenced by both Se and maternal nutritional plane. During the parturient process, HSe ewes tended to have greater (P = 0.06) concentrations of estradiol-17β than ASe ewes. Three hours after parturition a surge of GH was observed in ASe-RES ewes that was muted in HSe-RES ewes and not apparent in other ewes. Growth hormone area under the curve during the parturient process was increased (P < 0.05) in ASe-RES vs HSe-RES ewes. Ewes that were overfed during gestation had reduced (P < 0.05) estradiol-17β but greater IGF-I, triiodothyronine, and thyroxine (P < 0.05) compared with RES ewes. Even though ewes were transitioned to a common diet after parturition, endocrine status continued to be affected into lactation. Moreover, it appears that gestational diet may partially affect lactational performance through altered endocrine status.

Effects of nutritional plane and selenium supply during gestation on visceral organ mass and indices of intestinal growth and vascularity in primiparous ewes at parturition and during early lactation

Objectives were to investigate effects of nutritional plane and Se supply during gestation on visceral organ mass and intestinal growth and vascularization in ewes at parturition and during early lactation. Primiparous Rambouillet ewes (n = 84) were allocated to 2 × 3 × 2 factorial arrangement of treatments. Factors included dietary Se [adequate Se (ASe, 11.5 μg/kg BW) or high Se (HSe, 77.0 μg/kg BW)], nutritional plane [60% (restricted; RES), 100% (control; CON), or 140% (high; HIH)], and physiological stage at necropsy (parturition or d 20 of lactation). At parturition, lambs were removed and 42 ewes (7 per treatment) were necropsied. Remaining ewes were transitioned to a common diet which met lactation requirements and mechanically milked for 20 d. In the absence of interactions (P > 0.10), main effects are reported. At parturition, stomach complex and liver masses were greatest for HIH, intermediate for CON, and least for RES (P < 0.02). Small intestinal mass was greater (P ≤ 0.002) for HIH than RES and CON, and greater (P < 0.01) for ASe than HSe. During early lactation, RES and CON gastrointestinal masses increased disproportionally to BW (P < 0.05). At parturition, jejunal mucosal density was less (P ≤ 0.01) for RES than CON and HIH, whereas CON had greater (P < 0.003) jejunal mucosal RNA concentration and RNA:DNA than RES and HIH. Although there were no differences (P > 0.17) at parturition, jejunal cell percent proliferation was greatest in RES, intermediate in CON, and least in HIH (P ≤ 0.09) at d 20 lactation. At both stages, RES had less (P = 0.01) jejunal capillary area density than HIH and less (P ≤ 0.03) capillary surface density than CON and HIH. During lactation, jejunal capillary size was greater (P = 0.04) for ewes previously fed HSe compared with ASe. At parturition, ASe-HIH had greater (P < 0.02) jejunal mucosal endothelial nitric oxide synthase 3 mRNA than all other treatments and greater (P = 0.10) vascular endothelial growth factor (VEGF) than all treatments, except ASe-RES. In addition, CON had less (P ≤ 0.08) jejunal VEGF receptor-1 (FLT1) mRNA compared with RES and HIH, and ASe had greater (P = 0.003) FLT1 than HSe at parturition. Ewes fed HIH had greater (P = 0.04) jejunal VEGF receptor-2 mRNA compared with RES. Results indicate that maternal intestinal growth and vascularization are responsive to nutritional plane and dietary Se during gestation and undergo changes postpartum when under similar lactational management.

Prostacyclin prevents murine lung cancer independent of the membrane receptor by activation of peroxisomal proliferator--activated receptor gamma

Overexpression of prostacyclin synthase (PGIS) decreases lung tumor multiplicity in chemical- and cigarette-smoke-induced murine lung cancer models. Prostacyclin signals through a single G-protein-coupled receptor (IP), which signals through cyclic AMP. To determine the role of this receptor in lung cancer chemoprevention by prostacyclin, PGIS-overexpressing mice were crossed to mice that lack the IP receptor [IP(-/-)]. Carcinogen-induced lung tumor incidence was similar in IP(+/+), IP(+/-), and IP(-/-) mice, and overexpression of PGIS gave equal protection in all three groups, indicating that the protective effects of prostacyclin are not mediated through activation of IP. Because prostacyclin can activate members of the peroxisomal proliferator-activated receptor (PPAR) family of nuclear receptors, we examined the role of PPARgamma in the protection of prostacyclin against lung tumorigenesis. Iloprost, a stable prostacyclin analogue, activated PPARgamma in nontransformed bronchial epithelial cells and in a subset of human non-small-cell lung cancer cell lines. Iloprost-impregnated chow fed to wild-type mice resulted in elevated lung macrophages and decreased lung tumor formation. Transgenic animals with lung-specific PPARgamma overexpression also developed fewer lung tumors. This reduction was not enhanced by administration of supplemental iloprost. These studies indicate that PPARgamma is a critical target for prostacyclin-mediated lung cancer chemoprevention and may also have therapeutic activity.

The effect of residual feed intake classification on forage intake by grazing beef cows

Although feed intake and efficiency differences in growing cattle of low and high residual feed intake (RFI) classification have been established, little is known about the difference in grazed forage intake between beef cows of known RFI classification. Two experiments were conducted using Hereford cows for which RFI had been determined as heifers using the GrowSafe 4000E feed intake system, after which heifers had been divided into thirds as low RFI, mid RFI, and high RFI. During Exp. 1, 2 replicates of low and high RFI cows (n = 7/replicate) in mid- to late-gestation were blocked to 1 of 4 non-endophyte-infected tall fescue paddocks (1.8 to 2.4 ha), which they grazed continuously for 84 d during summer. Using grazing exclosures, weekly rising plate meter readings, and forage harvests every 21 d, average forage DMI was calculated. Low and high RFI groups did not differ (P > 0.05) in BW change or BCS change over the trial (19.5 vs. 22.1 kg of BW gain and 0.11 vs. 0.10 BCS gain), but low RFI cows had a 21% numerically lower DMI than high RFI cows (12.4 vs. 15.6 kg/d; P = 0.23). The average area needed per paddock over the trial was similar for low and high RFI cows (1.71 vs. 1.82 ha; P = 0.35), and the average DM on offer over the trial was less for low RFI than for high RFI cows (4,215 vs. 4,376 kg; P = 0.06). During Exp. 2, 3 replicates of low and high RFI cows with their calves (n = 4 pair/replicate) strip-grazed stockpiled and early spring growth tall fescue paddocks (0.7 to 0.9 ha) for 60 d in late winter and early spring. Because of limiting forage availability and quality at trial initiation, cow-calf pairs were also fed 3.31 kg/pair of pelleted soyhulls daily. Pre- and post-grazed forage samples were harvested for 4 grazing periods, and forage growth was estimated using a growing degree days calculation and on-site weather station data. Performance did not differ (P > 0.05) between low and high RFI cows throughout the experiment (18.4 vs. 26.6 kg of BW gain and -0.04 vs. 0.15 BCS gain). Despite the utilization of forage offered being similar for low and high RFI cow-calf pairs (P > 0.05), low RFI cows and their calves had an 11% numerically lower DMI than high RFI pairs (12.5 vs. 14.1 kg/d; P = 0.12). We concluded that either no intake differences existed between low and high RFI cows or that current methodology and small animal numbers limited our ability to detect differences.

Severity of Clostridium difficile-associated diarrhea in solid organ transplant patients

Clostridium difficile-associated diarrhea (CDAD) has a wide spectrum of disease severity. Studies have implicated immunosuppressants as a risk factor for severe disease. We hypothesized that solid organ transplant (SOT) patients with CDAD would be at greater risk for severe disease because of their profound immunosuppression. Adult SOT patients with CDAD seen at Duke University Medical Center between 1999 and 2003 were compared with a reference group of non-transplant patients with CDAD. The primary outcome was the development of complicated colitis defined as death, intensive care unit admission, or urgent colectomy within 30 days of diagnosis. A secondary outcome was relapse within 60 days. Eighty transplant and 86 non-transplant cases were reviewed. There was no significant difference in the development of complicated colitis (13.8% vs. 7.0%) or relapse rates (6.2% vs. 7.0%) between the 2 groups. In the entire sample, 18.5% of patients receiving corticosteroids unrelated to transplantation relapsed as compared with 4.5% not receiving corticosteroids (risk ratio 4.3, P=0.02). In conclusion, no significant difference was found in severity of CDAD between SOT patients and non-transplant patients. Exposure to corticosteroids was significantly associated with an increased risk of relapse and may warrant a longer treatment course.

Climate-based model predicting acarological risk of encountering the human-biting adult life stage of Dermacentor andersoni (Acari: Ixodidae) in a key habitat type in Colorado

We exploited an elevation (climate) gradient ranging from 1,700 to 2,500 m in Poudre Canyon of Larimer County, CO, to determine climatic correlates of abundance per 15-s drag sampling time unit (hereafter referred to as abundance) of the human-biting adult life stage of the Rocky Mountain wood tick, Dermacentor andersoni Stiles (Acari: Ixodidae), in a key risk habitat for tick exposure: south/west-facing, rocky hillsides with mixed grass-brush-conifer vegetation. The relationship between elevation and abundance was parabolic, with peak tick abundances occurring at mid-range elevations (2,200-2,400 m) and tick abundances approaching zero at approximately 2,100 and 2,500 m. Regression modeling demonstrated that abundance of host-seeking adult ticks in south/west-facing exposures was accurately predicted by several climate variables related to temperature (e.g., mean annual minimum temperature, maximum temperature, and base 10 degrees C growing degree-days, and median length of annual freeze-free period; r2 values ranging from 0.771 to 0.864), whereas mean annual precipitation, snowfall, or relative humidity were uninformative in this respect (r2 values ranging from 0.020 to 0.316). Abundance of D. andersoni adults peaked at a mean annual maximum temperature of approximately 10 degrees C and a mean annual growing degree-day value of approximately 650. Relationships between climate variables and abundance of D. andersoni adults were used to create geographic information system (GIS)-based models for predicted tick abundance in south/west-facing exposures in Larimer County. This is the first GIS-based model developed for spatial patterns of abundance of D. andersoni. Finally, preliminary data from Poudre Canyon indicate a shift toward peak abundances of D. andersoni adults occurring in sheltered northern/eastern exposures, rather than in drier and hotter southern/ western exposures, at elevations below 2,100 m.

Prostaglandin E2 receptor subtype 2 (EP2) null mice are protected against murine lung tumorigenesis

BACKGROUND

Manipulating prostaglandin (PG) production modulates tumor development. Elevated PGI2 production prevents murine lung cancer, while decreasing PGE2 content protects against colon cancer. PGE2 receptor subtype 2 (EP2) -deficient mice were hypothesized to be resistant to lung tumorigenesis.

MATERIALS AND METHODS

EP2 null BALB/c mice and their wild-type littermates were exposed to an initiation-promotion carcinogenesis protocol and lung tumorigenesis was examined. Chronic lung inflammation was induced to determine whether EP2 ablation influenced inflammatory cell infiltration.

RESULTS

Tumor multiplicity in EP2 null mice was 34% lower than in their wild-type littermates (21.9+/-3.0 vs. 14.5+/-2.9 tumors/mouse, p<0.001). The lung tumor burden, an indicator of growth rate, also declined (57%, p<0.05). All the mice exhibited similar inflammatory cell infiltration.

CONCLUSION

PGE2, acting through EP2, enhanced lung tumorigenesis through a mechanism that may be distinct from its proinflammatory activity. Thus, EP2 is a potential target for novel chemoprevention strategies.

Attenuation of the pulmonary inflammatory response following butylated hydroxytoluene treatment of cytosolic phospholipase A2 null mice

Administration of butylated hydroxytoluene (BHT) to mice causes lung damage characterized by the death of alveolar type I pneumocytes and the proliferation and subsequent differentiation of type II cells to replace them. Herein, we demonstrate this injury elicits an inflammatory response marked by chemokine secretion, alveolar macrophage recruitment, and elevated expression of enzymes in the eicosanoid pathway. Cytosolic phospholipase A(2) (cPLA(2)) catalyzes release of arachidonic acid from membrane phospholipids to initiate the synthesis of prostaglandins and other inflammatory mediators. A role for cPLA(2) in this response was examined by determining cPLA(2) expression and enzymatic activity in distal respiratory epithelia and macrophages and by assessing the consequences of cPLA(2) genetic ablation. BHT-induced lung inflammation, particularly monocyte infiltration, was depressed in cPLA(2) null mice. Monocyte chemotactic protein-1 (MCP-1) content in bronchoalveolar lavage fluid increases after BHT treatment but before monocyte influx, suggesting a causative role. Bronchiolar Clara cells isolated from cPLA(2) null mice secrete less MCP-1 than Clara cells from wild-type mice, consistent with the hypothesis that cPLA(2) is required to secrete sufficient MCP-1 to induce an inflammatory monocytic response.

Effects of dietary zinc and iron supplementation on mineral excretion, body composition, and mineral status of nursery pigs1,2

Two experiments were conducted to evaluate the effects of dietary Zn and Fe supplementation on mineral excretion, body composition, and mineral status of nursery pigs. In Exp. 1 (n = 24; 6.5 kg; 16 to 20 d of age) and 2 (n = 24; 7.2 kg; 19 to 21 d of age), littermate crossbred barrows were weaned and allotted randomly by BW, within litter, to dietary treatments and housed individually in stainless steel pens. In Exp. 1, Phases 1 (d 0 to 7) and 2 (d 7 to 14) diets (as-fed basis) were: 1) NC (negative control, no added Zn source); 2) ZnO (NC + 2,000 mg/kg as Zn oxide); and 3) ZnM (NC + 2,000 mg/kg as Zn Met). In Exp. 2, diets for each phase (Phase 1 = d 0 to 7; Phase 2 = d 7 to 21; Phase 3 = d 21 to 35) were the basal diet supplemented with 0, 25, 50, 100, and 150 mg/kg Fe (as-fed basis) as ferrous sulfate. Orts, feces, and urine were collected daily in Exp. 1; whereas pigs had a 4-d adjustment period followed by a 3-d total collection period (Period 1 = d 5 to 7; Period 2 = d 12 to 14; Period 3 = d 26 to 28) during each phase in Exp. 2. Blood samples were obtained from pigs on d 0, 7, and 14 in Exp. 1 and d 0, 7, 21, and 35 in Exp. 2 to determine hemoglobin (Hb), hematocrit (Hct), and plasma Cu, (PCu), Fe (PFe), and Zn (PZn). Pigs in Exp. 1 were killed at d 14 (mean BW = 8.7 kg) to determine whole-body, liver, and kidney mineral concentrations. There were no differences in growth performance in Exp. 1 or 2. In Exp. 1, pigs fed ZnO or ZnM diets had greater (P < 0.001) dietary Zn intake during the 14-d study and greater fecal Zn excretion during Phase 2 compared with pigs fed the NC diet. Pigs fed 2,000 mg/kg, regardless of Zn source, had greater (P < 0.010) PZn on d 7 and 14 than pigs fed the NC diet. Whole-body Zn, liver Fe and Zn, and kidney Cu concentrations were greater (P < 0.010), whereas kidney Fe and Zn concentrations were less (P < 0.010) in pigs fed pharmacological Zn diets than pigs fed the NC diet. In Exp. 2, dietary Fe supplementation tended to increase (linear, P = 0.075) dietary DMI, resulting in a linear increase (P < 0.050) in dietary Fe, Cu, Mg, Mn, P, and Zn intake. Subsequently, a linear increase (P < 0.010) in fecal Fe and Zn excretion was observed. Increasing dietary Fe resulted in a linear increase in Hb, Hct, and PFe on d 21 (P < 0.050) and 35 (P < 0.010). Results suggest that dietary Zn or Fe additions increase mineral status of nursery pigs. Once tissue mineral stores are loaded, dietary minerals in excess of the body's requirement are excreted.

Cytokines differentially regulate the synthesis of prostanoid and nitric oxide mediators in tumorigenic versus non-tumorigenic mouse lung epithelial cell lines

Studies using transgenic and knockout mice have demonstrated that particular cytokines influence lung tumor growth and identified prostaglandin E2 (PGE2), prostacyclin (PGI2) and nitric oxide (NO) as critical mediators of this process. PGE2 and NO were pro-tumorigenic while PGI2 was antitumorigenic. We describe herein an in vitro experimental approach to examine interactions among cytokines, prostaglandins (PGs) and NO. PGE2, PGI2, and NO levels were assayed in culture media from non-tumorigenic mouse lung epithelial cell lines, their spontaneous transformants and mouse lung tumor-derived cell lines, before or after exposure to the cytokines TNFalpha, IFNgamma and IL1beta, alone and in combination. More PGE2 than PGI2 was produced by neoplastic cells, while the opposite was observed in non-tumorigenic lines. Cytokine exposure magnified the extent of these differential concentrations. The PGE2 to PGI2 ratio was also greater in chemically-induced mouse lung tumors than in adjacent tissue or control lungs, supporting the physiological relevance of this in vitro model. Expression of PG biosynthetic enzymes in these cell lines correlated with production of the corresponding PGs. Cytokine treatment enhanced NO production by inducing the inflammation-associated biosynthetic enzyme, inducible NO synthase (iNOS), but this did not correlate with the neoplastic status of cells. Inhibition of iNOS or cyclooxygenase 2 activity using aminoguanidine or NS-398 respectively, demonstrated that NO did not affect PG production nor did PGs influence NO production. Since lack of iNOS inhibits mouse lung tumor formation, we propose that this is independent of any modulation of PG synthesis in epithelial cells. The similar normal/neoplastic trends in PGE2 to PGI2 ratios both in vitro and in vivo, together with an amplification of this difference upon cytokine exposure, are consistent with the hypothesis that cytokines released during inflammation exacerbate differences in the behavior of neoplastic and normal lung cells.

Relative amounts of antagonistic splicing factors, hnRNP A1 and ASF/SF2, change during neoplastic lung growth: Implications for pre-mRNA processing

Pre-mRNA processing is an important mechanism for globally modifying cellular protein composition during tumorigenesis. To understand this process during lung cancer, expression of two key pre-mRNA alternative splicing factors was compared in a mouse model of early lung carcinogenesis and during regenerative growth following reversible lung injury. Heterogeneous nuclear ribonucleoprotein (hnRNP) A1 and alternative splicing factor/splicing factor 2 (ASF/SF2) act antagonistically to modulate splice site selection. Both hnRNP A1 and ASF/SF2 contents rose in adenomas and during injury-induced hyperplasia compared to control lungs, as measured by immunoblotting. While both proteins increased similarly during compensatory hyperplasia, hnRNP A1 increased to a much greater extent than ASF/SF2 in tumors, resulting in a 6-fold increase of the hnRNP A1 to ASF/SF2 ratio. Immunohistochemical analysis showed that hnRNP A1 localized exclusively within tumor nuclei, while ASF/SF2 appeared in cytoplasm and/or nuclei, depending on the growth pattern of the tumor cells. We also demonstrated cancer-associated changes in the pre-mRNA alternative splicing of CD44, a membrane glycoprotein involved in cell-cell and cell-extracellular matrix interactions. hnRNP A1 and ASF/SF2 expression is thus differentially altered in neoplastic lung cells by mechanisms that do not strictly arise from increased cell division. These changes are influenced by tumor histology and may be associated with production of variant CD44 mRNA isoforms.

Targeted over-expression of mPGES-1 and elevated PGE2 production is not sufficient for lung tumorigenesis in mice

There is a significant body of evidence suggesting that enzymes involved in arachidonic acid metabolism and their eicosanoid products play a role in various cancers, having both pro- and antitumorigenic effects. The goal of this study was to further define the role microsomal prostaglandin E synthases (mPGES-1) play in lung tumorigenesis. Transgenic mice were created with targeted over-expression of human mPGES-1 in the alveolar and airway epithelial cells using an SP-C promoter driven construct. Transgene positive (mPGES-1+) mice were shown to significantly over-express functional mPGES-1 in the lung and more specifically in alveolar type II cells. To study the effects of mPGES-1 over-expression in lung tumor formation, mice were exposed to a complete carcinogen protocol with a single injection of urethane or an initiation/promotion model with a single injection of 3-methylcholanthrene (MCA) followed by multiple injections of butylated hydroxytoluene (BHT). mPGES-1+ mice did not show a significant difference in tumor multiplicity or tumor size at 10, 16, 19 or 30 weeks after urethane injection compared with mPGES-1- mice. No significant difference was seen in tumor incidence, multiplicity or size at 19 weeks after treatment with MCA/BHT. Western blots verified that mPGES-1 expression was increased in tumors versus uninvolved tissue of both mPGES-1+ and mPGES-1- mice with overall expression being significantly higher in mPGES-1+ mice. Cyclooxygenase-2 levels were elevated in tumors in both groups. From these studies we conclude that over-expression of mPGES-1 and highly elevated PGE2 production are not sufficient to induce lung tumors.

Decreased lung tumorigenesis in mice genetically deficient in cytosolic phospholipase A2

Epidemiological investigations suggest that chronic lung inflammation increases lung cancer risk. Pharmacologic and genetic evidence in mouse models indicates that lipid mediators released during pulmonary inflammation enhance lung tumor formation. Cytosolic phospholipase A2 (cPLA2) catalyzes arachidonic acid (AA) release from membrane phospholipids. AA can then lead to the synthesis of several classes of lipid mediators, including prostaglandin (PG) biosynthesis through the cyclooxygenase (COX) pathway. We investigated a role for cPLA2 in mouse lung tumorigenesis by using mice genetically deficient in cPLA2. After multiple urethane injections into cPLA2 null mice and wild-type littermates, the number of lung tumors was determined. cPLA2 null mice developed 43% fewer tumors (from 16 +/- 2 to 9 +/- 2 tumors/mouse; P < 0.05) than wild-type littermates. cPLA2, COX-1, COX-2 and microsomal prostaglandin E2 synthase (mPGES), examined by immunohistochemistry, are present in alveolar and bronchiolar epithelia and in alveolar macrophages in lungs from naive mice and tumor-bearing mice. Tumors express higher levels of each of these four enzymes than control lungs, as determined by immunoblotting. No differences were detected in the contents of COX-1, COX-2 and mPGES between wild-type and cPLA2 null mice. Although the steady-state levels of prostaglandin E2 and prostaglandin I2 in lung tissue extracts prepared from wild-type or cPLA2 (-/-) mice were not significantly different, both prostaglandins markedly increased in tumors from wild-type mice, an increase that was significantly blunted in tumors from cPLA2 (-/-) mice. These results demonstrate a role for cPLA2 in mouse lung tumorigenesis that may be mediated by decreased prostaglandin synthesis.

Serum levels of surfactant protein D are increased in mice with lung tumors

Most murine lung tumors are composed of differentiated epithelial cells. We have reported previously that surfactant protein (SP)-D is expressed in urethane-induced tumors. Serum levels of SP-D are increased in patients with interstitial lung disease and acute respiratory distress syndrome and in rats with acute lung injury but have not been measured in mice. In this study, we sought to determine whether SP-D could be detected in murine serum and discovered that it was increased in mice bearing lung tumors. Serum SP-D concentration was 5.0 +/- 0.2 ng/ml in normal C57BL/6 mice, essentially absent in SP-D nulls, and 63.6 +/- 9.0 ng/ml in SP-D-overexpressing mice. SP-D in serum was verified by immunoblotting. Serum SP-D was increased in mice bearing tumors induced by three different protocols, and the SP-D level correlated with tumor volume. However, in mice with a single adenoma or a few adenomas, SP-D levels were usually within the normal range. SP-D was expressed by the tumor cells, and there was also a field effect whereby type II cells near the tumor expressed more SP-D than type II cells in the remainder of the lung. Serum SP-D was also increased by lung inflammation. In airway inflammation induced by aerosolized ovalbumin in sensitized BALB/c mice, the serum levels were elevated after challenge. In conclusion, serum SP-D concentration is increased in mice bearing lung tumors and generally reflects the tumor burden but is also elevated during lung inflammation.

Genetic ablation of inducible nitric oxide synthase decreases mouse lung tumorigenesis

Inducible nitric oxide synthase (iNOS) content is elevated in human lung adenocarcinomas, and lung cancer patients exhale more nitric oxide (NO) than healthy individuals. The mechanism of this association of chronically elevated NO with tumorigenesis has not been defined. We investigated the role of iNOS in murine lung tumorigenesis, a model of human lung adenocarcinoma, using wild-type (+/+) and iNOS (-/-) mice. Genetic disruption of iNOS decreased urethane-induced lung tumor multiplicity by 80% (P < 0.0001). iNOS protein was expressed in lung tumors growing in wild-type mice and bronchiolar Clara cells isolated from normal mouse lungs, but was undetectable in whole lung extracts by immunoblotting. Because NO regulates vascular endothelial growth factor (VEGF) expression in other systems, we examined the effect of iNOS deficiency on VEGF protein concentration in mouse lung tumors. VEGF concentration was 54% lower in lung tumors isolated from iNOS (-/-) mice versus controls, implying that NO modulates angiogenesis in these tumors. Lung tumors also have elevated levels of cyclooxygenase (COX) -1 and COX-2 contents relative to normal lungs, but iNOS deficiency did not change COX expression in the tumors. Chronic inflammation predisposes mice to lung tumorigenesis; accordingly, we examined whether butylated hydroxytoluene-induced chronic lung inflammation was influenced by iNOS deficiency. Butylated hydroxytoluene-induced alveolar macrophage infiltration was unaffected by iNOS (-/-) status, suggesting that although NO is a critical mediator of mouse lung tumorigenesis, it is not essential in this model of lung inflammation. The substantial (80%) reduction in lung tumor multiplicity in iNOS (-/-) mice strongly supports examining iNOS-specific inhibitors as potential lung cancer chemopreventive agents.

Compatibility of the thioamide functional group with beta-sheet secondary structure: incorporation of a thioamide linkage into a beta-hairpin peptide

[structure: see text]. We report the incorporation of a thioamide linkage between the i + 2 and i + 3 residues of the type II' beta-turn of a peptide known to fold into a beta-hairpin conformation. Two-dimensional NMR spectroscopy and circular dichroism spectroscopy indicate that the thioxo peptide adopts a hairpin conformation similar to that of the oxo peptide and that the hairpin conformation persists at elevated temperatures. The results show that a thioamide linkage is compatible with beta-sheet secondary structure.

Therapeutic zygapophyseal joint injections for headaches emanating from the C2-3 joint

OBJECTIVE

To report our experience using fluoroscopically guided therapeutic intra-articular C2-3 zygapophyseal joint injections in patients with chronic headaches after a whiplash event.

DESIGN

Restrospective study (n = 18 patients) with independent clinical review. Each patient experienced persistent daily headache symptoms which failed to improve after at least 3 mo of physical therapy, activity restriction, and the use of oral analgesics. Each patient demonstrated initially a positive response to a diagnostic intra-articular C2-3 joint injection. Data collection and analysis were performed by an independent clinical reviewer. Outcome measures included headache frequency, medication usage, symptom response to medication, and employment status.

RESULTS

Patients' symptom duration before diagnostic injection averaged 34 mo. Follow-up data collection transpired at an average of 19 mo after the final therapeutic injection. In 61% of patients, fewer than three headaches were experienced each week; these headaches were relieved with the use of oral analgesics.

CONCLUSIONS

Although the inherent limitations of this study preclude a definitive statement regarding the efficacy of C2-3 injections, these initial findings suggest that therapeutic intra-articular zygapophyseal joint injections are effective in the treatment of headaches emanating from the C2-3 joint after a whiplash event. Future controlled, prospective studies are necessary to clarify the role of such injections in this challenging patient population.

Structural influences on the resolution of lexical ambiguity: an analysis of hemispheric asymmetries

Structural influences on lexical ambiguity resolution in the two cerebral hemispheres was investigated using a divided visual field procedure. Participants were presented with auditory Wh- sentences containing an ambiguous word, where the grammatical role of the word was apparent only at a sentence-final verb (e.g., "Which BANK did the woman see?"). Following a sentence, either immediately or after 600 ms, a target word was presented in either the right or left visual field. Targets were related to the ambiguous word's dominant meaning (MONEY), the subordinate meaning (RIVER), or were unrelated. With left visual field presentation, priming occurred for both dominant- and subordinate-related targets at a 0 ms delay, but only for dominant-related targets at 600 ms. With left visual field presentation, priming occurred for subordinate-related targets only at both delays. The results suggest that grammatical assignment triggers the selection of meaning in the left hemisphere, whereas processing in the right hemisphere operates independently of structural analyses.

Mechanisms of receptor-mediated rhinovirus neutralization defined by two soluble forms of ICAM-1

The majority of human rhinoviruses use intercellular adhesion molecule 1 (ICAM-1) as a cell surface receptor. Two soluble forms of ICAM-1, one corresponding to the entire extracellular portion [tICAM(453)] and one corresponding to the two N-terminal immunoglobulin-like domains [tICAM(185)], have been produced, and their effects on virus-receptor binding, virus infectivity, and virus integrity have been examined. Results from competitive binding experiments indicate that the virus binding site is largely contained within the two N-terminal domains of ICAM-1. Virus infectivity studies indicate that tICAM(185) prevents infection by direct competition for receptor binding sites on virus, while tICAM(453) prevents infection at concentrations 10-fold lower than that needed to inhibit binding and apparently acts at the entry or uncoating steps. Neutralization by both forms of soluble ICAM-1 requires continual presence of ICAM-1 during the infection and is largely reversible. Both forms of soluble ICAM-1 can alter rhinovirus to yield subviral noninfectious particles lacking the viral subunit VP4 and the RNA genome, thus mimicking virus uncoating in vivo, although this irreversible modification of rhinovirus is not the major mechanism of virus neutralization.

Identification of monoclonal antibody epitopes and critical residues for rhinovirus binding in domain 1 of intercellular adhesion molecule 1

Intercellular adhesion molecule 1 (ICAM-1) is the cellular receptor for the major group of human rhinoviruses (HRVs) and the adhesion ligand of lymphocyte function-associated antigen 1. Analysis of a series of chimeric exchanges between human and murine ICAM-1 shows that two distinct epitopes recognized by monoclonal antibodies that block rhinovirus attachment and cell adhesion map to the N-terminal first domain of ICAM-1. Furthermore the specificity for HRV binding is entirely contained within the first 88 amino acids. Mutagenesis of the four sites of N-linked glycosylation within the second domain shows that carbohydrate is not involved in virus recognition. Homologue replacement mutagenesis localizes the epitopes for virus-blocking antibodies to two regions of domain 1 predicted to form beta strand D and the loop between the F and G strands of an immunoglobulin-fold structure. Analysis of virus binding to the mutants predicts a large surface of contact between HRV and ICAM-1 domain 1 but shows that the regions most important for virus binding are coincident with the monoclonal antibody epitopes.

The major human rhinovirus receptor is ICAM-1

The major human rhinovirus receptor has been identified with monoclonal antibodies that inhibit rhinovirus infection. These monoclonal antibodies recognize a 95 kd cell surface glycoprotein on human cells and on mouse transfectants expressing a rhinovirus binding phenotype. Purified 95 kd protein binds to rhinovirus in vitro. Protein sequence from the 95 kd protein showed an identity with that of intercellular adhesion molecule-1 (ICAM-1); a cDNA clone obtained from mouse transfectants expressing the rhinovirus receptor had essentially the same sequence as ICAM-1. Thus, the major human rhinovirus receptor is ICAM-1. The gene for this receptor maps to human chromosome 19, which also contains the genes for a number of other picornavirus receptors.