In vitro screening of technical lignins to determine their potential as hay preservatives

Our objectives were to evaluate technical lignins for their antifungal properties against 3 molds and 1 yeast causing hay spoilage, and their ability to preserve ground high-moisture alfalfa hay nutritive value in vitro. In experiment 1, 8 technical lignins and propionic acid (PRP; positive control) were tested at a dose of 40 mg/mL. The experiment had a randomized complete block design (RCBD, 4 runs) and a factorial arrangement of 3 molds × 10 additives (ADV). The effects of the ADV on yeast were evaluated separately with a RCBD. Sodium lignosulfonate (NaL) and PRP were the only treatments with 100 ± 2.8% inhibition of fungi. In experiment 2, the minimum inhibitory concentration (MIC) for selected lignins and PRP were determined. At pH 4, NaL had the lowest MIC across the molds (20-33.3 mg/mL) and magnesium lignosulfonate (MgL) for the yeast (26.7) among the lignins. However, PRP had MIC values that were several-fold lower across all fungi (1.25-3.33). In experiment 3, a RCBD (5 blocks) with a 3 (ADV; NaL, MgL, and PRP) × 4 (doses: 0, 0.5, 1, and 3% wt/wt fresh basis) factorial arrangement of treatments was used to evaluate the preservative effects of ADV in ground high-moisture alfalfa hay inoculated with a mixture of the fungi previously tested and incubated under aerobic conditions in vitro. After 15 d, relative to untreated hay (14.9), dry matter (DM) losses were lessened by doses as low as 1% for NaL (3.39) and 0.5% for PRP (0.81 ± 0.77%). The mold count was reduced in both NaL at 3% (3.92) and PRP as low as 0.5% (3.94) relative to untreated hay (7.76 ± 0.55 log cfu/fresh g). Consequently, sugars were best preserved by NaL at 3% (10.1) and PRP as low as 0.5% (10.5) versus untreated (7.99 ± 0.283% DM), while keeping neutral detergent fiber values lower in NaL (45.9) and PRP-treated (45.1) hays at the same doses, respectively, relative to untreated (49.7 ± 0.66% DM). Hay DM digestibility was increased by doses as low as 3% for NaL (67.5), 1% MgL (67.0), and 0.5% PRP (68.5) versus untreated hay (61.8 ± 0.77%). The lowest doses increasing neutral detergent fiber digestibility relative to untreated hay (23.3) were 0.5% for MgL and PRP (30.5 and 30.1, respectively) and 1% for NaL (30.7 ± 1.09% DM). Across technical lignins, NaL showed the most promise as a potential hay preservative. However, its effects were limited compared with PRP at equivalent doses. Despite not having an effect on preservation, MgL improved DM digestibility by stimulating neutral detergent fiber digestibility. This study warrants further development of NaL under field conditions.

Center of Biomedical Research Excellence in Matrix Biology: Building Research Infrastructure, Supporting Young Researchers, and Fostering Collaboration

The Center of Biomedical Research Excellence in Matrix Biology strives to improve our understanding of extracellular matrix at molecular, cellular, tissue, and organismal levels to generate new knowledge about pathophysiology, normal development, and regenerative medicine. The primary goals of the Center are to i) support junior investigators, ii) enhance the productivity of established scientists, iii) facilitate collaboration between both junior and established researchers, and iv) build biomedical research infrastructure that will support research relevant to cell-matrix interactions in disease progression, tissue repair and regeneration, and v) provide access to instrumentation and technical support. A Pilot Project program provides funding to investigators who propose applying their expertise to matrix biology questions. Support from the National Institute of General Medical Sciences at the National Institutes of Health that established the Center of Biomedical Research Excellence in Matrix Biology has significantly enhanced the infrastructure and the capabilities of researchers at Boise State University, leading to new approaches that address disease diagnosis, prevention, and treatment. New multidisciplinary collaborations have been formed with investigators who may not have previously considered how their biomedical research programs addressed fundamental and applied questions involving the extracellular matrix. Collaborations with the broader matrix biology community are encouraged.

Symposium review: Technologies for improving fiber utilization

The forage lignocellulosic complex is one of the greatest limitations to utilization of the nutrients and energy in fiber. Consequently, several technologies have been developed to increase forage fiber utilization by dairy cows. Physical or mechanical processing techniques reduce forage particle size and gut fill and thereby increase intake. Such techniques increase the surface area for microbial colonization and may increase fiber utilization. Genetic technologies such as brown midrib mutants (BMR) with less lignin have been among the most repeatable and practical strategies to increase fiber utilization. Newer BMR corn hybrids are better yielding than the early hybrids and recent brachytic dwarf BMR sorghum hybrids avoid lodging problems of early hybrids. Several alkalis have been effective at increasing fiber digestibility. Among these, ammoniation has the added benefit of increasing the nitrogen concentration of the forage. However, few of these have been widely adopted due to the cost and the caustic nature of the chemicals. Urea treatment is more benign but requires sufficient urease and moisture for efficacy. Ammonia-fiber expansion technology uses high temperature, moisture, and pressure to degrade lignocellulose to a greater extent than ammoniation alone, but it occurs in reactors and is therefore not currently usable on farms. Biological technologies for increasing fiber utilization such as application of exogenous fibrolytic enzymes, live yeasts, and yeast culture have had equivocal effects on forage fiber digestion in individual studies, but recent meta-analyses indicate that their overall effects are positive. Nonhydrolytic expansin-like proteins act in synergy with fibrolytic enzymes to increase fiber digestion beyond that achieved by the enzyme alone due to their ability to expand cellulose microfibrils allowing greater enzyme penetration of the cell wall matrix. White-rot fungi are perhaps the biological agents with the greatest potential for lignocellulose deconstruction, but they require aerobic conditions and several strains degrade easily digestible carbohydrates. Less ruminant nutrition research has been conducted on brown rot fungi that deconstruct lignocellulose by generating highly destructive hydroxyl radicals via the Fenton reaction. More research is needed to increase the repeatability, efficacy, cost effectiveness, and on-farm applicability of technologies for increasing fiber utilization.

Pregnancy-induced changes in metabolome and proteome in ovine uterine flushings

Mass spectrometry (MS) approaches were used herein to identify metabolites and proteins in uterine flushings (UF) that may contribute to nourishing the conceptus. Ovine uteri collected on Day 12 of the estrous cycle (n = 5 ewes exposed to vasectomized ram) or Days 12 (n = 4), 14 (n = 5), or 16 (n = 5) of pregnancy (bred with fertile ram) were flushed using buffered saline. Metabolites were extracted using 80% methanol and profiled using ultraperformance liquid chromatography (LC) tandem mass spectrometry. The proteome was examined by digestion with trypsin, followed by the analysis of peptides with LC-MS/MS. Metabolite profiling detected 8510 molecular features of which 9 were detected only in UF from Day 14-16 pregnant ewes that function in fatty acid transport (carnitines), hormone synthesis (androstenedione like), and availability of nutrients (valine). Proteome analysis detected 783 proteins present by Days 14-16 of pregnancy in UF, 7 of which are as follows: annexin (ANX) A1, A2, and A5; calcium-binding protein (S100A11); profilin 1; trophoblast kunitz domain protein 1 (TKDP); and interferon tau (IFNT). These proteins function in endocytosis, exocytosis, calcium signaling, and inhibition of prostaglandins (annexins and S100A11); protecting against maternal proteases (TKDP); remodeling cytoskeleton (profilin 1); and altering uterine release of prostaglandin F2 alpha as well as inducing IFNT-stimulated genes in the endometrium and the corpus luteum (IFNT). Identifying metabolites and proteins produced by the uterus and conceptus advances our understanding of embryo/maternal signaling and provides insights into possible the causes of reproductive failure.

The current prevalence of asthma, allergic rhinitis, and eczema related symptoms in school-aged children in Costa Rica

OBJECTIVE

Asthma prevalence in Costa Rica is among the highest worldwide. We aimed to determine the prevalence of asthma among school-age children in the Central Highland Area of Costa Rica.

METHODS

Cross-sectional study using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was performed. Parents or guardians of children aged 6-13 years completed written questionnaires.

RESULTS

Total of 2817 school-aged children returned these questionnaires (74.1% return rate). The prevalence of asthma, rhinitis, and eczema was 21.9%, 42.6%, and 19.2%, respectively. The co-existence of the 3 diseases was seen in 22.6% of children with asthma. Boys had a slightly higher prevalence of these conditions, and younger children had higher prevalence of asthma and eczema, but lower prevalence of rhinitis than older children. The use of acetaminophen and antibiotics in the first 12 months of life showed a significant association with the prevalence of asthma, rhinitis, and eczema. Wheezing with exercise, dry cough at night, and ever rhinitis was highly associated with asthma symptoms in the last 12 months. In contrast, no association was found between children exposed to smoking at home. Frequent traffic next to the house was reported more frequently by the parents of children with asthma, although no significant association was found.

CONCLUSION

The prevalence of asthma showed a significant decrease compared to previous studies. However, there was an unexpected high prevalence of rhinitis. Exposure to acetaminophen and antibiotic during the first year of life was highly associated with asthma symptoms.

Effects of homolactic bacterial inoculant on the performance of lactating dairy cows

The objective of this experiment was to determine the effect of applying a homofermentative bacterial inoculant to corn silage on the performance of dairy cows. After harvesting, corn forage was treated with nothing (CON) or with an inoculant containing a mixture of Lactococcus lactis, Lactobacillus plantarum, and Enterococcus faecium at 1.5 × 10⁵ cfu/g of fresh forage (MC; SiloSolve MC, Chr. Hansen A/S, Hørsholm, Denmark). After 186 d of storage in Ag-Bags (A Miller-St. Nazianz Inc., St. Nazianz, WI), silages were fed as part of a total mixed ration containing 55% concentrates, 10% alfalfa hay, and 35% CON or MC corn silage. Sixty early-lactation Holstein dairy cows (30 multiparous and 30 primiparous) housed in a freestall barn with Calan gates (American Calan Inc., Northwood, NH) were assigned to the dietary treatments from 20 to 100 d in milk. Silage inoculated with MC had a more homofermentative pattern evidenced by greater lactic acid concentration (3.83 vs. 4.48% of DM) and lower concentrations of acetic (2.34 vs. 1.68% of DM) and propionic (0.37 vs. 0.10% of DM) acids and ammonia (9.11 vs. 7.82% of N) for CON and MC, respectively. Dry matter intake (23.1 vs. 23.2 kg/d) did not differ among treatments, but the MC silage had greater apparent digestibility of DM (68.8 vs. 70.8%), which led to greater yields of milk (37.7 vs. 38.5 kg/d), fat-corrected milk (37.6 vs. 38.4 kg/d), milk fat (1.30 vs. 1.33 kg/d), and lactose (1.83 vs. 1.92 kg/d) for CON and MC cows, respectively. Milk from cows fed MC silage had higher lactose (4.86 vs. 4.93%), lower protein (2.93 vs. 2.83%), and similar contents of fat (3.47 vs. 3.44%) compared with CON cows. Feed efficiency (fat-corrected milk/dry matter intake) was not affected by treatment (1.69 vs. 1.72 for CON and MC, respectively). Inoculation of corn silage with the homofermentative inoculant increased digestibility of the total mixed ration and increased milk yield by lactating dairy cows.

Laboratory silo type and inoculation effects on nutritional composition, fermentation, and bacterial and fungal communities of oat silage

The objectives were to evaluate (1) the use of 2 types of experimental silos (S) to characterize whole-crop oat (Avena sativa L.) silage with or without addition of an inoculant (I), and (2) the effect of inoculation on the microbial community structure of oats ensiled using only plastic bucket silos (BKT). From each of 6 sections in a field, oats were harvested, treated (INO) or not (CON) with inoculant, packed into 19-L BKT or vacuum bags (BG), and ensiled for 217 d. The inoculant added contained Lactobacillus buchneri and Pediococcus pentosaceus (4 × 10⁵ and 1 × 10⁵ cfu/g of fresh oats, respectively). The experimental design was a complete randomized design replicated 6 times. Treatment design was the factorial combination of 2 S × 2 I. Some differences existed between BG versus BKT at silo opening (217 d), including a decreased CP (7.73 vs. 7.04 ± 0.247% of DM) and ethanol (1.93 vs. 1.55 ± 0.155) and increased lactic acid (4.28 vs. 3.65 ± 0.241), respectively. Also, WSC and mold counts were reduced in BG versus BKT for CON (1.78 vs. 2.70 ± 0.162% of DM and 0.8 vs. 2.82 ± 0.409 log cfu/fresh g) but not for INO (∼1.53 and 1.55), respectively. Application of INO increased DM recovery (96.1 vs. 92.9 ± 0.63%), aerobic stability (565 vs. 133 ± 29.2 h), acetic acid (2.38 vs. 1.22 ± 0.116% of DM), and reduced NDF (65.0 vs. 67.0 ± 0.57), ADF (36.7 vs. 38.1 ± 0.60), ethanol (0.63 vs. 2.85 ± 0.155), and yeast counts (1.10 vs. 4.13 ± 0.484 log cfu/fresh g) in INO versus CON, respectively. At d 0, no differences were found for S and I on the nutritional composition and background microbial counts. Leuconostocaceae (82.9 ± 4.27%) and Enterobacteriaceae (15.2 ± 3.52) were the predominant bacterial families and unidentified sequences were predominant for fungi. A higher relative abundance of the Davidiellaceae fungal family (34.3 vs. 19.6 ± 4.47) was observed in INO versus CON. At opening (217 d), INO had a lower relative abundance of Leuconostocaceae (42.3 vs. 95.8 ± 4.64) and higher Lactobacillaceae (57.4 vs. 3.9 ± 4.65) versus CON. Despite several differences were found between BKT and BG, both techniques can be comparable for characterizing effects of INO on the most basic measures used in silage evaluation. The use of inoculant improved oat silage quality partially by a shift in the bacterial community composition during ensiling, which mainly consisted of an increased relative abundance of Lactobacillaceae and reduction of Leuconostocaceae relative to CON.

Low thermal conductivity and improved thermoelectric performance of nanocrystalline silicon germanium films by sputtering

Si x Ge1-x alloys are well-known thermoelectric materials with a high figure of merit at high temperatures. In this work, metal-induced crystallization (MIC) has been used to grow Si0.8Ge0.2 films that present improved thermoelectric performance (zT = 5.6 × 10(-4) at room temperature)--according to previously reported values on films--with a relatively large power factor (σ · S (2) = 16 μW · m(-1) · K(-2)). More importantly, a reduction in the thermal conductivity at room temperature (κ = 1.13 ± 0.12 W · m(-1) · K(-1)) compared to other Si-Ge films (∼3 W · m(-1) · K(-1)) has been found. Whereas the usual crystallization of amorphous SiGe (a-SiGe) is achieved at high temperatures and for long times, which triggers dopant loss, MIC reduces the crystallization temperature and the heating time. The associated dopant loss is thus avoided, resulting in a nanostructuration of the film. Using this method, we obtained Si0.8Ge0.2 films (grown by DC plasma sputtering) with appropriate compositional and structural properties. Different thermal treatments were tested in situ (by heating the sample inside the deposition chamber) and ex situ (annealed in an external furnace with controlled conditions). From the studies of the films by: x-ray diffraction (XRD), synchrotron radiation grazing incidence x-ray diffraction (SR-GIXRD), micro Raman, scanning electron microscopy (SEM), x-ray photoemission spectroscopy (XPS), Hall effect, Seebeck coefficient, electrical and thermal conductivity measurements, we observed that the in situ films at 500 °C presented the best zT values with no gold contamination.

Panniculitis caused by Mycobacterium monacense mimicking erythema induratum: a case in Ecuador

We report the first case of recently characterized species M. monacense associated with chronic nodular vasculitis, infecting a young woman. This case represents the first isolation of M. monacense from Ecuador. The isolate was identified by conventional and molecular techniques.

Temporal Release, Paracrine and Endocrine Actions of Ovine Conceptus-Derived Interferon-Tau During Early Pregnancy

The antiviral activity of interferon (IFN) increases in uterine vein serum (UVS) during early pregnancy in sheep. This antiviral activity in UVS collected on Day 15 of pregnancy is blocked by anti-IFN-tau (anti-IFNT) antibodies. Conceptus-derived IFNT was hypothesized to induce IFN-stimulated gene (ISG) expression in endometrium and extrauterine tissues during pregnancy. To test this hypothesis, blood was collected from ewes on Days 12-16 of the estrous cycle or pregnancy. Serum progesterone was >1.7 ng/ml in pregnant (P) and nonpregnant (NP) ewes until Day 13, then declined to <0.6 ng/ml by Day 15 in NP ewes. A validated IFNT radioimmunoassay detected IFNT in uterine flushings (UFs) on Days 13-16 and in UVS on Days 15-16 of pregnancy. IFNT detection in UF correlated with paracrine induction of ISGs in the endometrium and occurred prior to the inhibition of estrogen receptor 1 and oxytocin receptor expression in uterine epithelia on Day 14 of pregnancy. Induction of ISG mRNAs in corpus luteum (CL) and liver tissue occurred by Day 14 and in peripheral blood mononuclear cells by Day 15 in P ewes. Expression of mRNAs for IFN signal transducers and ISGs were greater in the CL of P than that of NP ewes on Day 14. It is concluded that: 1) paracrine actions of IFNT coincide with detection of IFNT in UF; 2) endocrine action of IFNT ensues through induction of ISGs in peripheral tissues; and 3) IFNT can be detected in UVS, but not until Days 15-16 of pregnancy, which may be limited by the sensitivity of the IFNT radioimmunoassay.

Is the Production of Embryos in Small-Scale Farming an Economically Feasible Enterprise?

The present assay attempts to evaluate the feasibility of using embryo transfer in small community farmers by in vivo study and by modelling the results obtained. From the total of 59 donor cows, 62.7% responded to treatment, with a significant difference (p = 0.002) in the percentage of the response between breeds, being 90.5% (19/21) in Holstein and 47.4% (18/38) in Brahman. A total of 283 embryos were graded as transferable, while 141 as non-transferable, without difference in the percentage of transferable embryo by breed (p = 0.18). The mean of transferable embryos graded as class I and II was not different between Holstein and Brahman (p = 0.96 and p = 0.92, respectively); besides, no differences were observed in the other grades (non-transferable). The highest difference in costs, regardless of its quality by breed, was seen in the lower levels of probable fertility of the embryo transferred, even reaching several hundred dollars. When modelling the expected costs for embryo produced and transferred, values can reach nearly $2000.00 when the probable fertility is only 10%. However, when the probable fertility was 60%, embryo cost was close to $300.00. This technology seems to be viable on average or high-scale systems, having a superovulatory response between 60 and 80% with 4-6 transferrable embryos. Yet, in small-scale farming, due to the reduced number of donors and/or recipients, the costs surpass the economical feasibility of the technique.

Functional roles of arginine during the peri-implantation period of pregnancy. III. Arginine stimulates proliferation and interferon tau production by ovine trophectoderm cells via nitric oxide and polyamine-TSC2-MTOR signaling pathways

In mammal species, arginine is a multifunctional amino acid required for survival, growth, and development of conceptuses (embryo/fetus and associated extraembryonic membranes) during the peri-implantation period of pregnancy. However, functional roles of arginine with respect to it being a substrate for production of nitric oxide (NO) and polyamines on trophectoderm cell proliferation and function remain largely unknown. To systematically assess roles of arginine in conceptus development and its effect on interferon tau (IFNT) production for pregnancy recognition signaling in ruminants, an established ovine trophectoderm (oTr1) cell line isolated from Day-15 ovine conceptuses were used to determine their response to arginine, putrescine, and NO donors, as well as their associated inhibitors. Arginine at physiological concentration (0.2 mM) stimulated maximum oTr cell proliferation (increased 2.0-fold at 48 h and 2.6-fold at 96 h; P < 0.05), stimulated IFNT production (IFNT/cell increased 3.1-fold; P < 0.05), and increased total protein per cell by more than 1.5-fold (P < 0.05). It also increased phosphorylated tuberous sclerosis protein (p-TSC2) and phosphorylated mechanistic target of rapamycin (MTOR) abundance by more than 2.7- and 4.3-fold (P < 0.0001) after long-term incubation, respectively. When Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; NO synthase inhibitor), DL-α-difluoromethylornithine hydrochloride hydrate (DFMO; ornithine decarboxylase inhibitor), and the combination (L-NAME + DFMO) were added, the effects of arginine on cell proliferation was reduced by 10.7%, 16.1%, and 22.3% (P < 0.05) at 48 h, and 15.3%, 27.2%, and 39.1% (P < 0.05) at 96 h of incubation, respectively, but values remained 1.5-fold higher (P < 0.05) than for the arginine-free control, which suggests that arginine, per se, serves as a growth factor. Both putrescine and NO stimulate cell proliferation via activation of the TSC2-MTOR signaling cascade, whereas only putrescine increased IFNT production. Collectively, our results indicate that arginine is essential for oTr1 cell proliferation and IFNT production via the NO/polyamine-TSC2-MTOR signaling pathways, particularly the pathway involving polyamine biosynthesis.

Effect of microbial inoculants on the quality and aerobic stability of bermudagrass round-bale haylage

The objective of this study was to compare the efficacy of using 4 commercially available microbial inoculants to improve the fermentation and aerobic stability of bermudagrass haylage. We hypothesized that the microbial inoculants would increase the fermentation and aerobic stability of the haylages. Bermudagrass (4-wk regrowth) was harvested and treated with (1) deionized water (control); (2) Buchneri 500 (B500; Lallemand Animal Nutrition, Milwaukee, WI) containing 1×10(5) of Pediococcus pentosaceus and 4×10(5) of Lactobacillus buchneri 40788; (3) Biotal Plus II (BPII; Lallemand Animal Nutrition) containing 1.2×10(5) of P. pentosaceus and Propionibacteria freudenreichii; (4) Silage Inoculant II (SI; AgriKing Inc., Fulton, IL) containing 1×10(5) of Lactobacillus plantarum and P. pentosaceus; and (5) Silo King (SK; AgriKing Inc.), containing 1×10(5) of L. plantarum, Enterococcus faecium, and P. pentosaceus, respectively. Forty round bales (8 per treatment; 441±26kg; 1.2×1.2 m diameter) were made and each was wrapped with 7 layers of plastic. Twenty bales were stored for 112 d and the remaining 20 were stored for 30 d and sampled by coring after intermediary storage periods of 0, 3, 7, and 30 d. The pH of control and inoculated haylages sampled on d 3 did not differ. However, B500 and BPII had lower pH (5.77±0.04 vs. 6.16±0.04; 5.06±0.13 vs. 5.52±0.13) than other treatments by d 7 and 30, respectively. At final bale opening on d 112, all treatments had lower pH than the control haylage (4.77±0.07 vs. 5.37±0.07). The B500, BPII, and SI haylages had greater lactic acid and lactic-to-acetic acid ratios than SK and control haylages. No differences were detected in neutral detergent fiber digestibility, dry matter losses, dry matter, lactic and acetic acid concentrations, and yeast and coliform counts. The SK haylage had lower clostridia counts compared with the control (1.19±0.23 vs. 1.99±0.23 cfu/g). Treatments B500, BPII, SI, and SK tended to reduce mold counts and they improved aerobic stability by 236, 197, 188, and 95%, respectively, compared with the control (276±22 vs. 99±22h).

Functional role of arginine during the peri-implantation period of pregnancy. II. Consequences of loss of function of nitric oxide synthase NOS3 mRNA in ovine conceptus trophectoderm

Nitric oxide (NO) is a gaseous molecule that regulates angiogenesis and vasodilation via activation of the cGMP pathway. However, functional roles of NO during embryonic development from spherical blastocysts to elongated filamentous conceptuses (embryo and extraembryonic membrane) during the peri-implantation period of pregnancy have not been elucidated in vivo. In order to assess roles of NO production in survival and development of the ovine conceptus, we conducted an in vivo morpholino antisense oligonucleotide (MAO)-mediated knockdown trial of nitric oxide synthase-3 (NOS3) mRNA, the major isoform of NO synthase, in ovine conceptus trophectoderm (Tr). Translational knockdown of NOS3 mRNA results in small, thin, and underdeveloped conceptuses, but normal production of interferon-tau, the pregnancy recognition signal in sheep. MAO-NOS3 knockdown in conceptuses decreased the abundance of NOS3 (72%, P < 0.05) and the arginine transporter SLC7A1 proteins in conceptus Tr. Furthermore, the amounts of ornithine and polyamines were less (P < 0.01) in uterine fluid, whereas the amounts of arginine (58%, P < 0.01), citrulline (68%, P < 0.05), ornithine (68%, P < 0.001), glutamine (78%, P < 0.001), glutamate (68%, P < 0.05), and polyamines (P < 0.01) were less in conceptuses, which likely accounts for the failure of MAO-NOS3 conceptuses to develop normally. For MAO-NOS3 conceptuses, there were no compensatory increases in the expression levels of either nitric oxide synthase-1 (NOS1) or nitric oxide synthase-2 (NOS2) or in expression of enzymes for synthesis of polyamines (ornithine decarboxylase, arginine decarboxylase, agmatinase) from arginine or ornithine with which to rescue development of MAO-NOS3 conceptuses. Thus, the adverse effect of MAO-NOS3 to reduce NO generation and the transport of arginine and ornithine into conceptuses is central to an explanation for failure of normal development of MAO-NOS3, compared to control conceptuses. The study, for the first time, created an NO-deficient mammalian conceptus model in vivo and provided new insights into the orchestrated events of conceptus development during the peri-implantation period of pregnancy. Our data suggest that NOS3 is the key enzyme for NO production by conceptus Tr and that this protein also regulates the availability of arginine in conceptus tissues for synthesis of polyamines that are essential for conceptus survival and development.

Ruminant Nutrition Symposium: Improving cell wall digestion and animal performance with fibrolytic enzymes

This paper aimed to summarize published responses to treatment of cattle diets with exogenous fibrolytic enzymes (EFE), to discuss reasons for variable EFE efficacy in animal trials, to recommend strategies for improving enzyme testing and EFE efficacy in ruminant diets, and to identify proteomic differences between effective and ineffective EFE. A meta-analysis of 20 dairy cow studies with 30 experiments revealed that only a few increased lactational performance and the response was inconsistent. This variability is attributable to several enzyme, feed, animal, and management factors that were discussed in this paper. The variability reflects our limited understanding of the synergistic and sequential interactions between exogenous glycosyl hydrolases, autochthonous ruminal microbes, and endogenous fibrolytic enzymes that are necessary to optimize ruminal fiber digestion. An added complication is that many of the standard methods of assaying EFE activities may over- or underestimate their potential effects because they are based on pure substrate saccharification and do not simulate ruminal conditions. Our recent evaluation of 18 commercial EFE showed that 78 and 83% of them exhibited optimal endoglucanase and xylanase activities, respectively, at 50 °C, and 77 and 61% had optimal activities at pH 4 to 5, respectively, indicating that most would likely act suboptimally in the rumen. Of the many fibrolytic activities that act synergistically to degrade forage fiber, the few usually assayed, typically endoglucanase and xylanase, cannot hydrolyze the recalcitrant phenolic acid-lignin linkages that are the main constraints to ruminal fiber degradation. These factors highlight the futility of random addition of EFE to diets. This paper discusses reasons for the variable animal responses to dietary addition of fibrolytic enzymes, advances explanations for the inconsistency, suggests a strategy to improve enzyme efficacy in ruminant diets, and describes differences among the proteomes of effective and ineffective EFE.

Pregnancy-associated genes contribute to antiluteolytic mechanisms in ovine corpus luteum

The hypothesis that ovine luteal gene expression differs due to pregnancy status and day of estrous cycle was tested. RNA was isolated from corpora lutea (CL) on days 12 and 14 of the estrous cycle (NP) or pregnancy (P) and analyzed with the Affymetrix bovine microarray. RNA also was isolated from luteal cells on day 10 of estrous cycle that were cultured for 24 h with luteolytic hormones (OXT and PGF) and secretory products of the conceptus (IFNT and PGE2). Differential gene expression (>1.5-fold, P < 0.05) was confirmed using semiquantitative real-time PCR. Serum progesterone concentrations decreased from day 12 to day 15 in NP ewes (P < 0.05) reflecting luteolysis and remained >1.7 ng/ml in P ewes reflecting rescue of the CL. Early luteolysis (days 12-14) was associated with differential expression of 683 genes in the CL, including upregulation of SERPINE1 and THBS1. Pregnancy on day 12 (55 genes) and 14 (734 genes) also was associated with differential expression of genes in the CL, many of which were ISGs (i.e., ISG15, MX1) that were induced when culturing luteal cells with IFNT, but not PGE2. Finally, many genes, such as PTX3, IL6, VEGF, and LHR, were stabilized during pregnancy and downregulated during the estrous cycle and in response to culture of luteal cells with luteolytic hormones. In conclusion, pregnancy circumvents luteolytic pathways and activates or stabilizes genes associated with interferon, chemokine, cell adhesion, cytoskeletal, and angiogenic pathways in the CL.

Conceptus-derived prostaglandins regulate gene expression in the endometrium prior to pregnancy recognition in ruminants

In cattle, the blastocyst hatches from the zona pellucida on days 8-9 and then forms a conceptus that grows and elongates into an ovoid and then filamentous shape between days 9 and 16. The growing conceptus synthesizes and secretes prostaglandins (PGs) and interferon τ (IFNT). Our hypothesis was that the ovoid conceptus exerts a local effect on the endometrium prior to maternal recognition of pregnancy on day 16 in cattle. In study one, synchronized cyclic heifers received no blastocysts or 20 in vitro-produced blastocysts on day 7 and their uteri were collected on day 13. IFNT was not detected by RIA in the uterine flushing samples of pregnant heifers containing multiple ovoid conceptuses; however, total PG levels were higher in the uterine lumen of pregnant heifers than in that of cyclic heifers. Microarray analysis revealed that the expression of 44 genes was increased in the endometria of day 13 pregnant heifers when compared with that in the endometria of cyclic heifers, and many of these genes were classical Type I IFN-stimulated genes (ISGs). In studies two and three, the effects of infusing PGs at the levels produced by the elongating day 14 conceptus into the uterine lumen of cyclic ewes on ISG expression in the endometrium were determined. Results indicated that the infusion of PGs increased the abundance of several ISGs in the endometrium. These studies support the hypothesis that the day 13 conceptus secretes PGs that act locally in a paracrine manner to alter gene expression in the endometrium prior to pregnancy recognition in cattle.

Fibrolytic enzyme and ammonia application effects on the nutritive value, intake, and digestion kinetics of bermudagrass hay in beef cattle

The objectives were to compare the effect of exogenous fibrolytic enzyme (Biocellulase A20) or anhydrous ammonia (4% DM) treatment on the nutritive value, voluntary intake, and digestion kinetics of bermudagrass (Cynodon dactylon cultivar Coastal) hay harvested after 2 maturities (5- and 13-wk regrowths). Six individually housed, ruminally cannulated Brangus steers (BW 325 ± 10 kg) were used in an experiment with a 6 × 6 Latin square design with a 3 (additives) × 2 (maturities) factorial arrangement of treatments. Each period consisted of 14 d of adaptation and 7, 4, 1, 1, and 4 d for measuring in vivo digestibility, in situ degradability, no measurements, rumen liquid fermentation and passage indices, and rate of solid passage, respectively. Steers were fed hay for ad libitum intake and supplemented with sugarcane molasses and distillers grain (supplement total of 2.88 kg DM/d). Enzyme did not affect the nutritional composition of hay but ammonia treatment decreased hay NDF, hemicellulose, and ADL concentrations and increased the CP concentration particularly for the mature lignified 13-wk hay. The enzyme increased NDF and hemicellulose digestibility of the 5-wk hay but decreased those of the 13-wk hay. Ammoniation decreased intake of hay but increased digestibility of DM, OM, NDF, hemicellulose, ADF, and cellulose and increased the ruminal in situ soluble and potentially digestible fractions and the rate of DM degradation of the 13-wk hay. Also, ammoniation increased the concentrations of ruminal NH3, total VFA, acetate, and butyrate but enzyme treatment did not. Neither enzyme addition nor ammoniation affected rate of liquid and solid passage. In conclusion, ammoniation decreased the concentration of most fiber fractions, decreased the intake of hays, and increased their CP concentration, in vivo digestibility, and in situ degradability at both maturities whereas enzyme application increased fiber digestibility of the 5-wk hay but decreased it in the case of the 13-wk hay.

First report of anthelmintic resistance in gastrointestinal nematodes of sheep from costa rica

As the prevalence and severity of anthelmintic resistance continue to rise, nematode infections in sheep correspondingly reduce the profitability of the sheep industry. In Costa Rica, sheep production systems are increasing in both number and importance. A field trial study was carried out to detect the level of anthelmintic resistance to albendazole and ivermectin in gastrointestinal nematodes (GIN) of sheep from seven farms in Costa Rica. Resistance was determined using the fecal egg count reduction test (FECRT). Three treatment groups were assessed on each farm: control, albendazole, and ivermectin. Haemonchus spp. (71%), Strongyloides sp. (57%), and Trichostrongylus spp. (43%) presented resistance levels to albendazole, whereas Strongyloides sp. (43%), Haemonchus spp. (29%), and Trichostrongylus spp. (29%) were resistant to ivermectin. Haemonchus spp., Strongyloides sp., and Trichostrongylus spp. were the most resistant GIN to both products. This study suggests that frequency of treatment, exclusive chemical control, and visual estimation of animal weight to calculate dosage may contribute to the high levels of anthelmintic resistance that were observed on the farms analyzed herein.

Detection of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii in horses from Costa Rica

Serum samples from 315 horses from Costa Rica, Central America, were examined for the presence of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii by using the surface antigen (SAG) SnSAG2 enzyme-linked immunosorbent assay (ELISA), the NhSAG1 ELISA, and the modified agglutination test, respectively. Anti- S. neurona antibodies were found in 42.2% of the horses by using the SnSAG2 ELISA. Anti- Neospora spp. antibodies were found in only 3.5% of the horses by using the NhSAG1 ELISA, and only 1 of these horses was confirmed seropositive by Western blot. Antibodies to T. gondii were found in 34.0% of the horses tested, which is higher than in previous reports from North and South America. The finding of anti- S. neurona antibodies in horses from geographical areas where Didelphis marsupialis has wide distribution suggests that D. marsupialis is a potential definitive host for this parasite and a source of infection for these horses.

Epidemiology of bovine anaplasmosis in dairy herds from Costa Rica

Bovine anaplasmosis is endemic and occurs in almost all areas of livestock production of Costa Rica. The aim of this study was to determine the seroprevalence and risk factors of anaplasmosis in dairy farms of Costa Rica by the recombinant truncated MSP-5 (rMSP-5) enzyme-linked immunosorbent assay (ELISA). Serum samples were obtained from 733 cattle from 20 commercial dairy herds of Costa Rica. The overall seroprevalence was 37.2% and herd seroprevalence ranged from 20.0 to 72.0%. The age-specific seroprevalence was 49.3% in young and 33.4% in adult animals. The main risk factors associated with seroprevalence were season of occurrence of clinical cases (rainy season) (OR=22.8), presence of tabanids (OR=9.5) and stable flies (OR=6.2), stable flies control measures (OR=3.2), non-use of ear tattoos (OR=2.8), interval of veterinary visit (≤ 60 days) (OR=2.7), altitude of the farms (<800 masl) (OR=2.6) and age (<2 years) (OR=1.8). The results indicated that exposure of cattle to Anaplasma marginale is common in dairy herds of Costa Rica and endemic instability situation probably is due to inadequate vector control.

First isolation and molecular characterization of Ehrlichia canis in Costa Rica, Central America

The present study investigated Ehrlichia species in blood samples from dogs suspected of clinical ehrlichiosis, using molecular and isolation techniques in cell culture. From a total of 310 canine blood samples analyzed by 16S rRNA nested PCR, 148 (47.7%) were positive for Ehrlichia canis. DNA from Ehrlichia chaffeensis or Ehrlichia ewingii was not detected in any sample using species-specific primers in separated reactions. Leukocytes from five PCR-positive dogs were inoculated into DH82 cells; successful isolation of E. canis was obtained in four samples. Partial sequence of the dsb gene of eight canine blood samples (including the five samples for in vitro isolation) was obtained by PCR and their analyses through BLAST showed 100% of identity with the corresponding sequence of E. canis in GenBank. This study represents the first molecular diagnosis, isolation, and molecular characterization of E. canis in dogs from Costa Rica.

Gastrointestinal safety and therapeutic efficacy of parenterally administered phosphatidylcholine-associated indomethacin in rodent model systems

BACKGROUND AND PURPOSE

Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) that is limited in its enteral or parenteral use by side effects of gastroduodenal bleeding and ulceration. We have investigated the ability of phosphatidylcholine associated with indomethacin to form a therapeutically effective drug (INDO-PC) with reduced gastrointestinal (GI) toxicity for parenteral use.

EXPERIMENTAL APPROACH

Rats were treated acutely by intravenous or chronically with subcutaneous injection of vehicle, indomethacin or INDO-PC using three related protocols. We then evaluated the following properties of these parenterally administered test drugs: (i) GI toxicity (luminal and faecal haemoglobin; intestinal perforations and adhesions; and haematocrit); (ii) bioavailability (plasma indomethacin); and (iii) therapeutic efficacy (analgesia from sensitivity to pressure; anti-inflammatory from ankle thickness; cyclo-oxygenase (COX) inhibition from synovial fluid prostaglandin E(2) concentration) in rats with adjuvant-induced joint inflammation.

KEY RESULTS

Acute and chronic dosing with INDO-PC produced less GI bleeding and intestinal injury than indomethacin alone, whereas the bioavailability, analgesic, anti-inflammatory and COX inhibitory activity of INDO-PC were comparable to indomethacin.

CONCLUSIONS AND IMPLICATIONS

The chemical association of phosphatidylcholine with indomethacin appears to markedly reduce the GI toxicity of the NSAID while providing equivalent therapeutic efficacy in a parenteral INDO-PC formulation.

Naproxen-PC: a GI safe and highly effective anti-inflammatory

We have been developing a family of phosphatidylcholine (PC)-associated NSAIDs, which appear to have improved GI safety and therapeutic efficacy in both rodent model systems and pilot clinical trials. As naproxen has been demonstrated to be associated with the lowest cardiovascular adverse events in comparison with both COX-2 selective inhibitors and conventional NSAIDs, we have been developing a Naproxen-PC formulation for evaluation in animal models and clinical trials. We have determined that an oil-based formulation of naproxen and triple strength soy lecithin provides excellent GI protection in both: 1) an acute NSAID-induced intestinal bleeding model in rats pretreated with L-NAME that are intragastrically administered a single dose of naproxen (at a dose of 50 mg/kg) vs the equivalent dose of Naproxen-PC; and 2) a more chronic model (at a naproxen dose of 25 mg/kg BID) in rats that have pre-existing hindpaw inflammation (induced with a intradermal injection of Complete Freund's Adjuvant/CFA). Both models demonstrate the superior GI safety of Naproxen-PC vs naproxen while this novel formulation had significant anti-inflammatory efficacy to reduce hindpaw edema and the generation of PGE(2) in the collected joint synovial fluid.

CONCLUSION

Naproxen-PC appears to induce significantly less GI injury and bleeding in two rodent model systems while maintaining anti-inflammatory and COX-inhibitory activity.

Seasonal idiopathic rhinitis with local inflammatory response and specific IgE in absence of systemic response

BACKGROUND

Patients with idiopathic rhinitis (IR) are considered to be nonallergic because they have a negative skin prick test (SPT) and allergen specific-IgE in serum. The concept of localized mucosal allergy in the absence of atopy has recently been proposed. The immunological mechanisms involved in seasonal IR have not been sufficiently studied. We examined nasal mucosa inflammation, the presence of nasal specific-IgE and the response to nasal allergen provocation test (NAPT) in patients with seasonal IR who presented symptoms only in spring.

METHODS

We evaluated 32 patients with seasonal IR and 35 with persistent allergic rhinitis to pollen (PAR-P) and compared these with healthy controls and persons with PAR to house dust mite during the pollen season, as well as by NAPT out-of-season with grass and Olea europea. We measured the nasal leukocyte-lymphocyte phenotype (CD45, CD33, CD16, CD3, CD4 and CD8), eosinophil-cationic-protein, and total and specific-IgE to grass and olive pollen in serum and nasal lavage and performed NAPT.

RESULTS

In the IR group, 62.5% had a positive NAPT (IR-PosNAPT), 20/32 to grass, with four of these having a positive NAPT to olive pollen as well. IR-PosNAPT patients showed a similar nasal leukocyte-lymphocyte profile to the PAR-P patients and different to controls. We detected nasal specific-IgE in 35% of IR-PosNAPT patients.

CONCLUSIONS

These results support the hypothesis that a subgroup of patients with IR have seasonal symptoms with evidence of a nasal allergic immune reaction in the absence of a positive SPT or serum specific IgE.

Direct observation of the phenomenology of a solid thermal explosion using time-resolved proton radiography

We present a new phenomenology for burn propagation inside a thermal explosion based on dynamic radiography. Radiographic images were obtained of an aluminum cased solid cylindrical sample of a plastic bonded formulation of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. The phenomenology observed is ignition followed by cracking in the solid accompanied by the propagation of a radially symmetric front of increasing proton transmission. This is followed by a further increase in transmission through the sample, ending after approximately 100 micros. We show that these processes are consistent with the propagation of a convective burn front followed by consumption of the remaining solid by conductive particle burning.

Fecal and serological survey of Neospora caninum in farm dogs in Costa Rica

To detect oocysts of Neospora caninum in dog feces and to determine the excretion pattern in dogs from specialized dairy farms in Costa Rica, a total of 265 fecal samples from 34 dogs were collected at intervals from February to August 2005. Fecal samples were examined for N. caninum-like oocysts microscopically, by DNA detection using the polymerase chain reaction (PCR), and by bioassay. N. caninum DNA was detected by PCR in four fecal samples, twice from one dog, but oocysts were not detected microscopically in these dogs. Sera of 31 of 34 dogs were tested for antibodies to N. caninum by a competitive-inhibition ELISA (VMRD). Fifteen (48.4%) of 31 dogs had antibodies to N. caninum by ELISA. Seroconversion was not found in 28 dogs that were bled twice, 4 months apart (March and July 2005). Only one dog tested positive to N. caninum by both ELISA and PCR. This is the first report of finding N. caninum DNA in feces of naturally infected dogs in Costa Rican dairy farms.

Surface phospholipids in gastric injury and protection when a selective cyclooxygenase-2 inhibitor (Coxib) is used in combination with aspirin

BACKGROUND AND PURPOSE

Clinical studies demonstrate that aspirin consumption reverses the gastrointestinal (GI) benefits of coxibs, by an undefined mechanism.

EXPERIMENTAL APPROACH

Rodent models were employed to investigate the effects of combinations of celecoxib and aspirin on gastric ulcerogenesis, bleeding, surface hydrophobicity (by contact angle analysis) and ulcer healing. We also evaluated the effects of phosphatidylcholine (PC)-associated aspirin in these rodent models and confirmed its cyclooxygenase (COX)-inhibitory activity by measuring mucosal prostaglandin E(2) (PGE(2)) concentration. We present evidence that aspirin's ability to induce gastric injury and bleeding in rats, was exacerbated in the presence of a coxib and was dependent on its ability to reduce gastric surface hydrophobicity. In contrast, co-administration of phosphatidylcholine (PC)-associated aspirin and celecoxib induced little or no gastric injury/bleeding and maintained the stomach's hydrophobic properties. Interestingly, aspirin and aspirin/PC equally inhibited gastric mucosal PGE(2) concentration. Aspirin in combination with a coxib retarded the healing of experimentally induced gastric ulcers, whereas healing rates of rats treated with celecoxib in combination with aspirin/PC were comparable to controls.

CONCLUSIONS AND IMPLICATIONS

Aspirin's gastric toxicity in combination with a coxib can be dissociated from its ability to inhibit COX-1 and appears to be dependent, in part, on its ability to attenuate the stomach's surface hydrophobic barrier. This adverse drug interaction between aspirin and coxibs, which impacts the treatment of osteoarthritic and cardiac patients requiring cardiovascular prophylaxis, can be circumvented by the administration of phosphatidylcholine (PC)-associated aspirin, to maintain the stomach's hydrophobic properties.

On the effect of nanocrystallization and disorder on the magnetic properties of Cu-rich, FeMnCu alloys

We report on the temperature dependencies of the Mössbauer spectra and the AC magnetic susceptibility measured in Cu-rich, FeMnCu samples prepared by mechanically alloying, using, on the one side, Cu and prealloyed FeMn powders and, on the other, pure element Cu, Mn, and Fe powders. From the correlation of the Mössbauer and susceptibility data we conclude about the basic characteristics of the phase distributions present in the different studied samples. Those distributions are a consequence of both the nanostructure induced upon milling and of the different signs of the Mn/Cu (negative) and Fe/Cu (positive) enthalpies of mixing. The proposed phase distributions are significantly different in the samples prepared from different precursors and this fact is analyzed in terms of the disproportion of the precursor FeMn alloy and in those of the favoured Mn/Cu interdiffusion and the hindered Fe/Cu one.

Effect of neosporosis on productive and reproductive performance of dairy cattle in Costa Rica

A cross-sectional study was conducted to assess the effect of neosporosis on productive and reproductive parameters in dairy cows. Cows (n=2743) from 94 farms located in the most important dairy areas in Costa Rica were used in the study. The size of the herds ranged from 32 to 379 females (mean=110, median=125). An indirect ELISA was used to determine the serostatus of the cows towards Neospora caninum. The effect of neosporosis on milk production was analysed by a mixed linear model. In addition, the effects on calving interval (days) and calving to conception interval (days) were analysed by survival analysis. The risk of abortion in relation to N. caninum serostatus was assessed by logistic regression, with herd as a random effect. Overall, 1185 of 2743 cows (43.3%) were seropositive for Neospora. Eighty-nine of 94 (94.7%) farms were classified as Neospora-seropositive. It was estimated that cows seronegative to Neospora produced an additional 84.7L of milk (P=0.6). Serostatus did not have a significant effect on the length of the calving interval in the Cox proportional hazard survival analysis (Hazard ratio=1.2, 95% CI: 0.9, 1.4). The logistic regression model had a weak positive association between serostatus and abortion (OR 1.7, 95% CI: 0.8, 3.9), but did not show a strong association between serostatus and the number of services per conception (OR=0.95, 95% CI: 0.7, 1.3). In conclusion, there were no significant effects of Neospora serostatus on production and reproductive performance in this study.

Effect of a killed whole Neospora caninum tachyzoite vaccine on the crude abortion rate of Costa Rican dairy cows under field conditions

A standard field trial was carried out to assess the effect of a commercial Neospora-vaccine based on whole killed tachyzoites (Bovilis-Neoguard, Intervet) on the abortion rate. Eight hundred and seventy-six cows, over 2.5 months pregnant, belonging to 25 Costa Rican dairy herds, were used in the analysis. For each cow vaccinated, a cow of the same herd, breed and age category, was selected as control. The period of administration of treatments extended from June to November of 2000. The treatments were administered in two, 5-ml doses 1 month apart, the first dose given between day 75 and 90 of gestation. The incidence of abortion among all treated cows was of 16.0% (140/876). The treatment specific incidence was 11.2% (49/438) and 20.8% (91/438) for the vaccinated and the placebo group, respectively. The prevented fraction by vaccination amounted to 0.46 (95% CI: 0.26, 0.61), and the cumulative incidence ratio for the vaccinated group was 0.54. The Cox hazard ratio was 0.51(95% CI: 0.37, 0.72), meaning that the force of abortion is reduced twice in the vaccinated group. The results of this study, the first one following this type of design, shows that the killed whole Neospora caninum tachyzoite preparation had a reasonable effect on the abortion rate in Costa Rican dairy cattle.

The effect of the dam-calf relationship on serostatus to Neospora caninum on 20 Costa Rican dairy farms

An epidemiological study was conducted on 20 dairy herds previously diagnosed as seropositive for Neospora caninum. The number of females per farm varies from 41 to 296. All females present on the farms were bled once in the period of July and August 2000. A total of 3002 females were bled. An indirect ELISA was used to determine the serostatus of the animals. The analysis of the data was performed in four steps: (1) descriptive statistics about the serological status and general characteristics of the cattle; (2) calculation of vertical and horizontal transmission; (3) an univariate analysis and, (4) a multivariate logistic regression analysis with herd as random effect. The within-herd seroprevalence varied between 25.0% (34/136) and 70.5% (203/288). Seven hundred and forty-seven dam-daughter pairs were available, involving daughters of any age. Daughters in the specific age-class of 2- and 3-years old had a higher seroprevalence (P<0.01) compared with younger and older age-classes. The risk of being seropositive when being born to a mother that tested seropositive (prevalence ratio (PR)) was 2.8-fold increased which coincides with a 5.3-fold increased odds. The probability of horizontal infection amounts to 0.22. The probability of a seropositive offspring due to vertical transmission was 0.64 (attributable fraction among exposed (AFexp)). The multivariate logistic regression showed a significant 6.0-fold increased odds for being seropositive when born from a seropositive mother. Also the within-herd seroprevalence level was significantly associated with the serostatus of the daughters. In the specific conditions of the dairy herds involved in this study, the serostatus of the cows should be not used as a predictor of the serostatus of daughters due to the increased probability of horizontal transmission.

Factors associated with Neospora caninum serostatus in cattle of 20 specialised Costa Rican dairy herds

Twenty-five specialised Costa Rican dairy farms (located in the Poás area) were used to determine neosporosis seroprevalence and the association of seropositivity with environmental and management factors. The farms involved were selected intentionally and all of them use VAMPP 5.1 (Veterinary Automated Management and Production Control Programme) as management-information system. Holstein-Friesian, Jersey and crosses between them were the most-frequent breeds in these herds. The number of females per farm varied from 41 to 296. Our cross-sectional study had two phases. In the first phase, we determined the presence or absence of seropositivity at herd level. For the second phase, all females in 20 seropositive farms were bled. Serum samples were tested for antibodies to Neospora caninum using an indirect enzyme-linked immunosorbent assay (ELISA). A questionnaire with factors mentioned in the literature was administered to the farmers. Logistic regression (LR with herd as random effect) was used to assess the relationships of the serostatus at the individual level with characteristics of the cows and environmental factors. In the first phase all herds had >20% seropositive females; therefore, all herds were eligible for the second phase. In the second phase, the overall prevalence was 39.7% (1191/3002), and within-herd prevalences were between 25.0 and 70.5%. Age 3-6 years, parity < or =2 of the dam of the cow, Jersey breed and lack of purposive sampling to diagnose abortive infectious disease were associated with positive serostatus; other management and environmental factors did not show significant associations. The lack of association between management and environmental factors with serostatus might be because all farms were exposed to a considerable number of potential factors. That all herds of this study were seropositive for neosporosis and the within-herd prevalence was considerable raises questions about how far the infection is spread in other dairy areas of Costa Rica.

Phosphatidylcholine association increases the anti-inflammatory and analgesic activity of ibuprofen in acute and chronic rodent models of joint inflammation: relationship to alterations in bioavailability and cyclooxygenase-inhibitory potency

We investigated whether chemical association of phosphatidylcholine (PC) to ibuprofen enhances the anti-inflammatory/analgesic activity of the nonsteroidal anti-inflammatory drug (NSAID) and whether any change in therapeutic action is due to alterations in drug bioavailability and cyclooxygenase (COX) inhibitory activity. Acute/chronic joint inflammation was induced in rats, by injection of Complete Freund's Adjuvant. In the acute study, rats were administered saline, ibuprofen, or PC-ibuprofen (at NSAID doses of 10, 25, and 50 mg/kg), and 2 h later the pain threshold of the affected joint to pressure was measured. PC-ibuprofen increased the pain threshold at all NSAID doses, whereas unmodified ibuprofen demonstrated analgesic activity at only the highest dose. In the chronic study, we investigated the effects of saline, PC-ibuprofen, and ibuprofen (administered at 15 and 25 mg/kg/day) on ankle thickness and pain threshold, and demonstrated that PC-ibuprofen had significantly greater anti-inflammatory and analgesic activity than ibuprofen, over a 30- to 60-day period. PC association resulted in reduced uptake (decreased Cmax), a modest increase in the area under the curve, and a longer t(1/2) of ibuprofen. We also demonstrated that PC-ibuprofen was a comparable or a more effective inhibitor of both 6-keto-prostaglandin F1alpha concentration of fluid collected from tissue in and around the inflamed stifle joint, and COX-2 activity in activated human umbilical vein endothelial cells. In conclusion, we have demonstrated that PC association results in increases in ibuprofen's anti-inflammatory and analgesic activity in rodent models of acute and chronic joint inflammation, and this effect may relate to alterations in drug bioavailability and COX-inhibitory potency.

Helicobacter infection and phospholipase A2 enzymes: effect of Helicobacter felis-infection on the expression and activity of sPLA2 enzymes in mouse stomach

The murine gastric mucosa possesses very high secretory type phospholipase A2 activity. Northern and Western blots indicated that the pancreatic-type, sPLA2-IB represents the predominant form of sPLA2 enzymes present in the gastric mucosa. Both sPLA2-IB mRNA and protein in the gastric mucosa exceeded levels found in the pancreas, and in contrast to the pancreatic enzyme it was present primarily in the active state. The sPLA2-IB gene is not expressed in the murine small intestine and colon. Infection by the gastritis-inducing bacteria, Helicobacterfelis (H. felis) dramatically and time dependently decreased the PLA2 activity in the glandular stomach of the mouse strain, C57BL/6, sensitive to the organism, which appeared to be related to a decrease in the percentage of sPLA2-IB present in the active form. This bacterial-induced reduction in PLA2 activity was not observed in BALB/c mice that fail to develop gastritis in response to H. felis infection. C57BL/6 mice do not, while BALB/c mice express, the PLA2-II enzyme. The H. felis-induced reduction in sPLA2-IB activity may weaken the gastric barrier by reducing the local concentration of arachidonic and linoleic acid, liberated from membrane phospholipids, the major precursors of 'cytoprotective' prostaglandins. Data presented here suggest that both sPLA2-IB and sPLA2-II enzymes may contribute to the gastric response to Helicobacter infection.

Longitudinal studies in the epidemiology of vesicular stomatitis on Costa Rican dairy farms

Twenty-three Costa Rican dairy herds from an vesicular stomatitis (VS) endemic area were under an active surveillance between April 1997 and March 1999. Ninety-two confirmed cases of VS New Jersey were found. Factors associated with clinical cases of VS virus New Jersey were: Parity (animals of parity 4 or 5 were 5.3 times more likely to present a clinical case than animals of parity 3 and lower; on the other hand, animals of parity 6 and higher showed an odds 4.6 times greater than animals of parity 3 and lower.) Ecological life zone (animals in premountain moist forest were 7.4 times more likely to present clinical cases than animals in lower mountain rain forest). Factors associated with seropositivity at the time of birth were farm and breed (Jersey calves had an odds 14.7 times greater than Holstein calves). Seroconversion, defined as the first twofold increase in the titers of the blood, was associated with farm and showed four peaks during the study period, September (wet season) 1997, February (dry season) 1998, September 1998, and February 1999. Finally, time to event analysis showed difference between farms and age, older animals showed the first seroconversion earlier than younger animals.

Recombinant human lactoferrin is effective in the treatment of Helicobacter felis-infected mice

Recombinant human lactoferrin possesses in-vitro antibiotic and anti-inflammatory activity similar to the native form. It was tested for in-vivo activity in mice infected with the gastritis-inducing bacterium Helicobacter felis. A two-week course of treatment with lactoferrin was sufficient to partially reverse both infection-induced gastritis and the infection rate, and fully reverse gastric surface hydrophobicity changes. A comparison of lactoferrin with amoxicillin and standard triple therapy revealed no differences in infection rate. These results show that recombinant human lactoferrin is effective in a mouse model of Helicobacter infection, and support further testing of this promising agent for this application.

Effect of bisphosphonates on surface hydrophobicity and phosphatidylcholine concentration of rodent gastric mucosa

Bisphosphonates are a family of chemically related zwitterionic molecules that are used clinically to retard bone resorption in individuals with osteoporosis and associated skeletal diseases. Inflammation and ulceration of the upper gastrointestinal tract by a mechanism that relates to a topical irritant action is associated with the consumption of some bisphosphonates. In the present study, we investigated the effects of three bisphosphonate molecules, pamidronate, alendronate, and risedronate on the surface hydrophobicity and phosphatidylcholine (PC) concentration of the antral mucosa. We also examined how these surface changes related to mucosal injury in an established rat model, in which the test compounds were administered in combination with indomethacin. We initially determined that a combination of pamidronate (300 mg/kg) and indomethacin (40 mg/kg) induced a significant reduction in mucosal surface hydrophobicity and macroscopic lesion formation by 15 min and mucosal PC concentration by 30 min, with the magnitude of these changes increasing over the 4-hr study period. An equivalent dose of alendronate or risedronate in combination with indomethacin produced modest or no macroscopic injury, respectively, to the antral mucosa over the 4-hr study, although the bisphosphonates clearly induced surface injury and some glandular necrosis when examined at the light microscopic level. These bisphosphonates also induced modest decreases in antral surface hydrophobicity and mucosal PC concentration that appeared to be related to their injurious potential. In conclusion, the variable toxicity of bisphosphonates to the antral mucosa appears to be associated with their ability to compromise the surface hydrophobic phospholipid barrier of the tissue, with pamidronate > > > alendronate > risedronate. This bisphosphonate effect on the surface barrier may trigger the development of mucosal injury and possible ulceration.

Altered gastrin regulation in mice infected with Helicobacter felis

Altered gastrin expression associated with Helicobacter pylori infection may contribute to the pathogenesis of peptic ulcer disease or gastric cancer in man, but gastrin has not been investigated in a murine model of Helicobacter infection. C57BL/6 mice were inoculated with Helicobacter felis and examined after 4-21 weeks for G and D cell numbers, antral gastrin and somatostatin mRNA, and luminal pH. In H. felis-infected mice, gastrin mRNA declined at four and six weeks after infection to 57% and 23%, respectively, of uninfected control values. Concurrently, somatostatin mRNA showed no change at four weeks and a modest 25% decrease at six weeks after infection. Similar reductions were noted in G and D cell numbers, resulting in a decrease in the G/D cell ratio after mice were infected with H. felis. Infected animals also showed a loss of parietal and chief cells, and an increased gastric pH. H. felis infection in C57BL/6 mice leads to an early suppression of G cell number and gastrin mRNA. These changes precede an alteration in somatostatin cell number and mRNA and, coupled with reductions in parietal and chief cells, may contribute both to severe impairment of gastric acid output and the potential for carcinogenic processes.

Neuropsychological sequelae of heat stroke: report of three cases and discussion

Heat stroke includes neurologic impairment as a person's body temperature reaches 40.5 degrees C (105 degrees F) as a result of a failure of thermoregulation. The physiologic complications of heat stroke are well described in the literature. The domains of cognitive functioning affected and the severity of impairment resulting from heat stroke can vary from mild deficits in attention and memory to severe global dementia. There can also be changes in affect and personality that are equally debilitating. This article presents the neuropsychological test results of three active duty soldiers who suffered heat stroke and were tested within 2.5 months of injury.

Phospholipid association reduces the gastric mucosal toxicity of aspirin in human subjects

OBJECTIVE

In previous studies on rats, we have shown that aspirin (ASA)-induced injury to the gastric mucosa is markedly reduced or completely abolished if ASA is chemically associated with the phospholipid, phosphatidylcholine (PC). We have also shown that the protective effect of PC does not influence the ability of ASA to inhibit mucosal cyclooxygenase (COX) activity in the stomach and other tissues. We therefore sought to assess the effect of PC-associated ASA (ASA/PC) on the gastric mucosa of normal volunteers and to compare the results with the use of ASA alone.

METHODS

Sixteen normal healthy subjects were administered ASA or ASA/PC in a randomized, double-blind, crossover study. The subjects received ASA in a dose of 650 mg three times a day for 3 days or an equivalent dose of ASA chemically associated with PC. Endoscopy was performed at baseline and again on the morning of day 4, after the subjects had taken the final dose of the test drug. On both occasions, antral biopsy specimens were obtained for the assessment of mucosal COX activity and prostaglandin concentration.

RESULTS

The number (mean +/- SD) of gastric erosions seen with the ASA/PC formulation was significantly less than when ASA was used alone (8.7 +/- 10.7 vs 2.9 +/- 4.3; p < 0.025). A similar trend was seen in the duodenum but the difference was statistically not significant. The antral mucosal COX activity, as well as the level of prostaglandin 6-keto PGF1alpha, were reduced significantly (80-88%) and to a similar extent by both ASA and ASA/PC.

CONCLUSIONS

The present study shows that acute aspirin-induced damage to the gastric mucosa can be reduced by chemically associating ASA with PC. The mechanism of mucosal protection provided by this compound is not related to any alteration in the ability of ASA to inhibit mucosal COX activity. We believe this protection is attributable to the maintenance of the defensive hydrophobic barrier of the gastric mucosa.

Effect of ranitidine bismuth citrate on the phospholipase A2 activity of Naja naja venom and Helicobacter pylori: a biochemical analysis

BACKGROUND

Helicobacter pylori has become recognized as a fundamental pathogen in the development of gastritis and peptic ulcer disease. Bismuth compounds in combination with antibiotics are widely used to treat H. pylori associated peptic ulcer disease.

METHODS

In this study we measured and analysed the inhibitory effect of ranitidine bismuth citrate (RBC, Pylorid, Tritec) on the activity and kinetics of phospholipase A2 (PLA2) (E.C.3.1.1.4) of commercial cobra (Naja naja) venom and H. pylori (French press lysates) using L-alpha-dipalmitoyl-(2[1-14C]palmitoyl)-phosphatidylcholine as substrate.

RESULTS

Our data suggest that RBC might exert a dose-dependent uncompetitive inhibition on PLA2 activity of both H. pylori and Naja naja venom. the inhibitory effect of RBC on the PLA2 activity cannot be abolished by the optimal concentration of calcium (10 mM), indicating its mechanism to be unrelated to the displacement of calcium from the activation site of the enzyme.

CONCLUSION

Our results suggest that one of the mechanisms by which bismuth compounds are therapeutically effective in the treatment of H. pylori associated gastritis is by inhibiting the activity of the degradative PLA2 enzyme secreted by H. pylori. As a consequence of the inhibitory action of RBC on PLA2 of the bacteria, the extracellular and/or intracellular phospholipid components of the gastric mucosal barrier are preserved.

Interaction of indomethacin and naproxen with gastric surface-active phospholipids: a possible mechanism for the gastric toxicity of nonsteroidal anti-inflammatory drugs (NSAIDs)

The possibility that the molecular mechanism underlying the topical gastric irritancy of nonsteroidal anti-inflammatory drugs (NSAIDs) may involve alterations in the surface-active properties of gastric phospholipids was investigated. Indomethacin and naproxen were intragastrically administered to rats and the hydrophobicity of the luminal surface of the stomach wall was assessed by contact angle analysis. Both NSAIDs have the ability to attenuate the phospholipid-related hydrophobic properties of the gastric mucosa by more than 80-85% in a dose-dependent fashion. Potential molecular interactions between both NSAIDs and surface-active phospholipids were analyzed using fluorescent probes. Indomethacin has the ability to displace, in a dose-dependent manner, ANS (1-anilino-8-naphthalene sulphonate), a fluorescent anionic probe previously bound to the head group of phosphatidylcholine molecules. Estimations of the resonance fluorescence transfer between naproxen and the surface probe ANS or the hydrophobic probe, pyrene, bound to dipalmitoylphosphatidylcholine (DPPC) vesicles revealed that naproxen diffuses within the phospholipid bilayers. The dynamic of the gastric lipid material extracted from the surface scraping material (SSM) of the mucosa was altered by the NSAID as shown by the increase in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) (at 25 degrees, rSSM = 0.106+/-0.006, rssM + indomethacin = 0.137+/-0.005, and rSSM + naproxen = 0.133+/-0.007, P < 0.001). The thermodynamic behavior of a model bilayer containing DPPC was also perturbed by the NSAIDs tested. These results provide evidence that NSAIDs may reduce the ability of gastric surface-active phospholipids to form a hydrophobic protective layer.

Attenuation of hydrophobic phospholipid barrier is an early event in Helicobacter felis-induced gastritis in mice

Helicobacter pylori infection has been linked to the development of gastritis which can then progress to a number of disease entities including peptic ulcer disease and gastric cancer. Since the pathogenic mechanism by which the bacteria causes gastritis is unresolved, we employed a model system, the H. felis-infected mouse to investigate the temporal relationship between bacterially-induced alterations in the hydrophobic phospholipid barrier of the stomach and the development of gastritis. In the present study, C57BL/6 mice were inoculated with 10(9) CFU of H. felis and the changes in gastric wet weight, histology, surface hydrophobicity, phospholipid/phosphatidylcholine concentration, phospholipase A2 activity, and the pH of collected gastric juice were measured 0.5-2 months postinoculation. In related experiments, we investigated the effects of treating H. felis infected mice with antibiotic/ bismuth therapy on the above gastric properties. It was determined that both gastric surface hydrophobicity and phospholipid composition were significantly attenuated as early as 2-4 weeks postinfection, preceding signs of mucosal inflammation and glandular atrophy as indicated by increases in gastric wet weight, pH and a disappearance in parietal cells. These early H. felis-induced changes in gastric surface hydrophobicity and phospholipid concentration were reversed by antibiotic/bismuth therapy. Based on these results we conclude that H. felis infection induces an early transformation of the stomach from a hydrophobic to an acid-sensitive hydrophilic state that may trigger the subsequent development of gastritis.