A fixed-dose approach to conducting emamectin benzoate tolerance assessments on field-collected sea lice, Lepeophtheirus salmonis.

In New Brunswick, Canada, the sea louse, Lepeophtheirus salmonis, poses an on-going management challenge to the health and productivity of commercially cultured Atlantic salmon, Salmo salar. While the in-feed medication, emamectin benzoate (SLICE® ; Merck), has been highly effective for many years, evidence of increased tolerance has been observed in the field since late 2008. Although bioassays on motile stages are a common tool to monitor sea lice sensitivity to emamectin benzoate in field-collected sea lice, they require the collection of large numbers of sea lice due to inherent natural variability in the gender and stage response to chemotherapeutants. In addition, sensitive instruments such as EC(50) analysis may be unnecessarily complex to characterize susceptibility subsequent to a significant observed decline in efficacy. This study proposes an adaptation of the traditional, dose-response format bioassay to a fixed-dose method. Analysis of 657 bioassays on preadult and adult stages of sea lice over the period 2008-2011 indicated a population of sea lice in New Brunswick with varying degrees of susceptibility to emamectin benzoate. A seasonal and spatial effect was observed in the robustness of genders and stages of sea lice, which suggest that mixing different genders and stages of lice within a single bioassay may result in pertinent information being overlooked. Poor survival of adult female lice in bioassays, particularly during May/June, indicates it may be prudent to consider excluding this stage from bioassays conducted at certain times of the year. This work demonstrates that fixed-dose bioassays can be a valuable technique in detecting reduced sensitivity in sea lice populations with varying degrees of susceptibility to emamectin benzoate treatments.

Zinc status and cognitive function of pregnant women in Southern Ethiopia.

The relation between zinc status and cognitive function was examined in a cross-sectional study in the Sidama area of Southern Ethiopia. Pregnant women >24 weeks of gestation from three adjacent rural villages volunteered to participate. Mean (s.d.) plasma zinc of 99 women was 6.97 (1.07) mumol/l (below the cutoff of 7.6 mumol/l indicative of zinc deficiency at this stage of gestation). The Raven's Coloured Progressive Matrices (CPM) test was administered individually. Scores for the Raven's scale A, which is the simplest scale, ranged from 4 to 10 of a possible 12. Women with plasma zinc <7.6 mumol/l had significantly lower Raven's CPM scale A scores than women with plasma zinc concentrations >7.6 mumol/l. Plasma zinc and maternal age and education predicted 17% of the variation in Raven's CPM scale A scores. We conclude that zinc deficiency is a major factor affecting cognition in these pregnant women.

Eosinophilic "empyema" associated with crack cocaine use.

Smoking of crystalline cocaine, known as "crack" cocaine, has been associated with eosinophilic pneumonitis, but not with pleural effusions. We describe a patient with eosinophilic pneumonitis with an eosinophilic "empyema" after using "crack" cocaine. The illness resolved with corticosteroids. We hypothesised that his effusion would have increased levels of eosinophil cytokines that promote oedema, and found a marked increase in pleural vascular endothelial growth factor (VEGF) and smaller increases in interleukins IL-5, IL-6, and IL-8. In the setting of "crack" use, we suggest that a pleural effusion that appears grossly to be pus should be evaluated for eosinophilic inflammation. Such eosinophilic effusions may respond to corticosteroids alone, consistent with a non-infectious process driven by proinflammatory cytokines.

First in vitro directed biosynthesis of new compounds by a minimal type II polyketide synthase: evidence for the mechanism of chain length determination.

The minimal actinorhodin polyketide synthase bearing two point mutations (KSbeta Q161A, ACP C17S) was chemically modified to carry novel C4 to C8 starter units on the ACP: on incubation with an excess of malonyl CoA new 16-carbon polyketides are made, supporting a measuring mechanism.

Expression and activation of 15-lipoxygenase pathway in severe asthma: relationship to eosinophilic phenotype and collagen deposition.

BACKGROUND: Although 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), a product of 15-lipoxygenase (15-LO), may be involved in mild to moderate asthma, little is known about its potential roles in severe asthma. OBJECTIVES: This study was performed to evaluate 15(S)-HETE levels in bronchoalveolar lavage fluid (BALF) from severe asthmatics with and without airway eosinophils and from the control groups. In addition, 15-LO protein expression was examined in endobronchial biopsy, while its expression and activation were evaluated in BAL cells. RESULTS: While 15(S)-HETE levels in BALF were significantly higher in all severe asthmatics than normal subjects, severe asthmatics with airway eosinophils had the highest levels compared with mild, moderate asthmatics and normal subjects. 15(S)-HETE levels were associated with tissue eosinophil numbers, sub-basement membrane thickness and BALF tissue inhibitor of metalloproteinase-1 levels, and were accompanied by increased 15-LO expression in bronchial epithelium. In addition, activation of 15-LO was suggested by the increased proportion of 15-LO in the cytoplasmic membrane of alveolar macrophages from severe asthmatics. CONCLUSION: The data suggest that severe asthmatics with persistent airway eosinophils manifest high levels of 15(S)-HETE in BALF, which may be associated with airway fibrosis. It is likely that 15-LO expression and activation by airway cells explain the increased 15(S)-HETE levels.

Rat alveolar type II cells inhibit lung fibroblast proliferation in vitro.

Fibroblasts stimulate alveolar type II epithelial cell differentiation and proliferation in vitro and during lung development. However, little is known about the effects of adult type II cells on fibroblasts. We investigated the effect of adult rat type II cells on proliferation of adult human lung fibroblasts. Fibroblasts were suspended within rat tail collagen which was gelled on a floating polycarbonate filter, and type II cells were cultured on Matrigel. In this coculture system, alveolar type II cells inhibited fibroblast proliferation and indomethacin blocked the inhibitory effect on fibroblast growth. Prostaglandin (PG) E2, the major PG secreted by type II cells, inhibited fibroblast proliferation and was increased during the period of inhibition of fibroblast proliferation. Incubation with arachidonate showed that most of the PGE2 in the coculture system was produced by the fibroblasts. In addition, we found that rat type II cells also inhibited rat fibroblasts and that inhibition of fibroblast growth by type II cells could be stimulated by keratinocyte growth factor. We conclude that in this coculture system, type II cells inhibit fibroblast proliferation by secreting a factor(s) that stimulates PGE2 production by fibroblasts, and that PGE2 directly inhibits fibroblast proliferation.

Persistent wheezing in very young children is associated with lower respiratory inflammation.

Despite advances in understanding the pathophysiology of asthma, morbidity and mortality in pediatrics continue to rise. Little is known about the initiation and chronicity of inflammation resulting in asthma in this young population. We evaluated 20 "wheezing" children (WC) (median age 14.9 mo) with a minimum of two episodes of wheezing or prolonged wheezing > or = 2 mo in a 6-mo period with bronchoscopy and bronchoalveolar lavage (BAL). Comparisons were made with six normal controls (NC) (median age 23.3 mo) undergoing general anesthesia for elective surgery. BAL fluid cell counts and differentials were determined. The eicosanoids, leukotriene (LT) B(4), LTE(4), prostaglandin (PG)E(2), and 15-hydroxyeicosatetraenoic acid (HETE) and the mast cell mediators, beta-tryptase and PGD(2), were evaluated by enzyme immunoassay (EIA). WC had significant elevations in total BAL cells/ml (p = 0.01), as well as, lymphocytes (LYMPH, p = 0.007), macrophages/monocytes (M&M, p = 0.02), polymorphonuclear cells (PMN, p = 0.02), epithelial cells (EPI, p = 0.03), and eosinophils (EOS, p = 0.04) compared with NC. Levels of PGE(2) (p = 0.0005), 15-HETE (p = 0.002), LTE(4) (p = 0.04), and LTB(4) (p = 0.05) were also increased in WC compared with NC, whereas PGD(2) and beta-tryptase were not. This study confirms that inflammation is present in the airways of very young WC and may differ from patterns seen in adults with asthma.

Exhaled nitric oxide correlated with induced sputum findings in COPD.

STUDY OBJECTIVES: Neutrophilic airway inflammation may underlie the pathogenesis of COPD. We examined repeated measurements of the fractional concentration of exhaled nitric oxide (FENO) and the correlation with cells and mediators in induced sputum (IS) from patients with COPD. PARTICIPANTS: Eleven COPD subjects (9 men and 2 women, aged 46 to 69 years) with predicted FEV(1) of 45 to 70%. SETTING: A hospital research laboratory. DESIGN: Single-cohort, prospective study with four visits at two weekly intervals. INTERVENTIONS: FENO and spirometry were assessed at all visits, and IS for differential cell count, leukotriene-B(4) (LTB(4)) and interleukin (IL)-8, nitrite, and nitrate at visit 1, visit 3, and visit 4. RESULTS: During the study, there were significant declines in mean percent predicted FEV(1), from 55.2 to 51.6% (p = 0.029), and mean FEV(1)/FVC ratio, from 50.4 to 45.4% (p = 0.001), accompanied by a significant increase in FENO geometric mean (95% confidence limits), from 15.2 (10.9 to 21.2) to 23.6 (17.1 to 32.4) parts per billion (p = 0.037), and sputum LTB(4), from 1.79 (1.03 to 3.11) to 3.57 (1.95 to 6.53) ng/mL (p = 0.033), but no significant change in other sputum parameters. From visits 1 to 4, the change in percent neutrophils correlated with the changes in FENO and IL-8 (r = 0.648, p = 0.028; r = 0.60, p = 0.05, respectively). Hypertonic saline solution induction of sputum caused a fall in FEV(1), from 1.83 +/- 0.44 to 1.46 +/- 0.44 L (p = 0.049). CONCLUSIONS: The worsening spirometry results were accompanied by significant increases in FENO and sputum LTB(4). FENO may be related to neutrophilic inflammation driven by the chemoattractant IL-8. FENO and IS may be useful markers of airway inflammation in COPD patients. Sputum induction with hypertonic saline solution causes a significant fall in FEV(1) requiring appropriate caution.

The measurement of cysteinyl leukotrienes in urine.

The cysteinyl leukotrienes, comprising leukotriene (LT) C4 and its major metabolites LTD4 and LTE4, are inflammatory lipid mediators derived from metabolism of arachidonic acid by 5-lipoxygenase. These leukotrienes have received considerable attention for their potential role in asthma and other inflammatory diseases. Since there is a potential role for these lipid mediators in both health and disease, the analysis of leukotrienes in biological fluids, especially urine, has generated significant interest.

Dietary phytate reduction improves zinc absorption in Malawian children recovering from tuberculosis but not in well children.

High dietary phytate content that compromises zinc nutriture is thought to be a major problem among children of the developing world. Zinc stable isotope techniques permit the quantitative assessment of the effect of phytate reduction on zinc homeostasis. We tested the hypothesis that zinc absorption would be increased in Malawian children fed a reduced-phytate corn-plus-soy diet compared with a standard high phytate diet. Twenty-three children hospitalized in Blantyre, Malawi, were enrolled. Children were selected from those recovering from tuberculosis and from well children (those with minor injuries, those awaiting elective surgery or healthy siblings). Children received a diet of corn-plus-soy porridge (either low phytate or high phytate) for a period of 3-7 d and then participated in a zinc stable isotope study. The study included the administration of oral and intravenous zinc stable isotopes and 7-d collections of urine and stool. The diet was maintained throughout the duration of specimen collection. Zinc isotopic enrichments in urine and stool were measured, and zinc fractional absorption, total zinc absorption, endogenous fecal zinc, net zinc retention and size of the exchangeable zinc pool were calculated. Among the 14 children recovering from tuberculosis, dietary phytate reduction resulted in higher fractional absorption (0.41 +/- 0.14 versus 0.24 +/- 0.09, mean +/- SD, P: < 0.05) and total zinc absorption (169 +/- 55 versus 100 +/- 46 microg/(kg. d), P: < 0.05). No effect of phytate reduction was seen in the well children (n = 9). Phytate reduction did not decrease the absolute endogenous fecal zinc, but it did decrease it relative to total absorbed zinc. These preliminary results indicate that phytate reduction may be beneficial in improving zinc nutriture in groups with increased zinc requirements who consume a cereal-based diet.