Lessons learnt from the field: a qualitative evaluation of adolescent experiences of a universal mental health education program

teen Mental Health First Aid (teenMHFA) is a school-based mental health program that trains adolescents to support peers who are experiencing mental health problems or crises. The program has been evaluated for adolescents aged 15-18 years as part of a randomized controlled trial, however qualitative feedback from students on their perceptions of the program is yet to be explored. The current study describes the perspectives of students who took part in the trial. Feedback on the perceived strengths and weaknesses of the program was provided by 979 Year 10 students (M = 15.82 years, female = 43.94%, English as a first language = 72.77%) at four government funded public schools in Melbourne, Australia via online surveys. A content and thematic analysis was performed on the data using a six-step process. Students generally found the program relevant and they connected with the visual material, personal stories and interactive activities. Suggestions for improvements included encouraging active student participation in classroom discussion and providing opportunities to practice skills. School-based mental health education can benefit from input from stakeholder perspectives, particularly when designing mental health content for delivery by external trainers.

'Venus trapped, Mars transits': Cu and Fe redox chemistry, cellular topography and in situ ligand binding in terrestrial isopod hepatopancreas

Woodlice efficiently sequester copper (Cu) in ‘cuprosomes' within hepatopancreatic ‘S' cells. Binuclear ‘B’ cells in the hepatopancreas form iron (Fe) deposits; these cells apparently undergo an apocrine secretory diurnal cycle linked to nocturnal feeding. Synchrotron-based µ-focus X-ray spectroscopy undertaken on thin sections was used to characterize the ligands binding Cu and Fe in S and B cells of Oniscus asellus (Isopoda). Main findings were: (i) morphometry confirmed a diurnal B-cell apocrine cycle; (ii) X-ray fluorescence (XRF) mapping indicated that Cu was co-distributed with sulfur (mainly in S cells), and Fe was co-distributed with phosphate (mainly in B cells); (iii) XRF mapping revealed an intimate morphological relationship between the basal regions of adjacent S and B cells; (iv) molecular modelling and Fourier transform analyses indicated that Cu in the reduced Cu⁺ state is mainly coordinated to thiol-rich ligands (Cu–S bond length 2.3 Å) in both cell types, while Fe in the oxidized Fe³⁺ state is predominantly oxygen coordinated (estimated Fe–O bond length of approx. 2 Å), with an outer shell of Fe scatterers at approximately 3.05 Å; and (v) no significant differences occur in Cu or Fe speciation at key nodes in the apocrine cycle. Findings imply that S and B cells form integrated unit-pairs; a functional role for secretions from these cellular units in the digestion of recalcitrant dietary components is hypothesized.

Beliefs about dangerousness of people with mental health problems: the role of media reports and personal exposure to threat or harm

PURPOSE

To assess the associations between beliefs about the dangerousness of people with mental health problems and exposure to media reports of violence or personal experiences of fear, threat or harm.

METHODS

Telephone interviews were carried out with 5220 Australians aged 18+. Respondents heard a vignette of a person with depression or early schizophrenia and were asked whether they believed him to be dangerous. Other questions covered past 12-month recall of media reports of violence and mental health problems, contact with and experiences of fear, threat or harm by people with mental health problems. Multinomial logistic regression was used to assess the associations between beliefs about dangerousness and media and these types of contact with people with mental health problems.

RESULTS

For the early schizophrenia vignette, recall of media reports and having felt afraid of someone were associated with beliefs about dangerousness. For the depression vignette, media reports about violence and mental health problems or the experiences of feeling afraid or having been threatened or harmed were not strongly associated with beliefs about dangerousness. For both vignettes, knowing someone with a mental health problem and having a higher level of education were associated with less belief in dangerousness.

CONCLUSIONS

Media reports may play a greater role in forming attitudes in low prevalence disorders and further efforts to reduce any adverse impact of media reporting should focus on these disorders. The study also supports the effectiveness of contact with people with mental health problems in reducing beliefs about dangerousness.

Protoplast fusion in a petite-negative yeast, Kluyveromyces lactis

The technique of protoplast fusion has been applied to the problem of unstable diploidy in the yeast Kluyveromyces lactis. By protoplast fusion between heterothallic strains of like mating-type, sporulation-deficient hybrids can be obtained. Biochemical, cytological, and genetical characterisation of these hybrids suggests that the majority of fusion products are diploid. Sporulating hybrids can be constructed by protoplast fusion between homothallic strains. Tetrad analysis of these hybrids demonstrates conclusively the diploid nature of fusion products.

The extraction of single-particle diffraction patterns from a multiple-particle diffraction pattern

The structures of biological molecules may soon be determined with X-ray free-electron lasers without crystallization by recording the coherent diffraction patterns of many identical copies of a molecule. Most analysis methods require a measurement of each molecule individually. However, current injection methods deliver particles to the X-ray beam stochastically and the maximum yield of single particle measurements is 37% at optimal concentration. The remaining 63% of pulses intercept no particles or multiple particles. We demonstrate that in the latter case single particle diffraction patterns can be extracted provided the particles are sufficiently separated. The technique has the potential to greatly increase the amount of data available for three-dimensional imaging of identical particles with X-ray lasers.

The Jenner Society and the Edward Jenner Museum: tributes to a physician-scientist

Dr. Edward Jenner's discovery and application of vaccination against smallpox was one of the most important medical advances of all time. In the modern era many millions of lives are saved each year by vaccines that work essentially on the same scientific principles established by Jenner more than 200 years ago. Jenner's country home in Berkeley, Gloucestershire, UK, where he carried out his work and where he spent most of his life, is now a museum and something of a shrine for vaccinologists. Jenner's house is also now the focal point of a new international learned society dedicated to advancing modern vaccinology. The aims of the new Jenner Society are to engage, support, and sustain the professional goals of vaccinologists, and to perpetuate the memory of Dr. Edward Jenner. Ultimately it is hoped that the Jenner Society will be recognized as one of the leading academic societies representing and promoting vaccine science around the world. We invite readers to consider joining the society (http://www.edwardjennersociety.org/).

Quality of information sources about mental disorders: a comparison of Wikipedia with centrally controlled web and printed sources

BACKGROUND

Although mental health information on the internet is often of poor quality, relatively little is known about the quality of websites, such as Wikipedia, that involve participatory information sharing. The aim of this paper was to explore the quality of user-contributed mental health-related information on Wikipedia and compare this with centrally controlled information sources.

METHOD

Content on 10 mental health-related topics was extracted from 14 frequently accessed websites (including Wikipedia) providing information about depression and schizophrenia, Encyclopaedia Britannica, and a psychiatry textbook. The content was rated by experts according to the following criteria: accuracy, up-to-dateness, breadth of coverage, referencing and readability.

RESULTS

Ratings varied significantly between resources according to topic. Across all topics, Wikipedia was the most highly rated in all domains except readability.

CONCLUSIONS

The quality of information on depression and schizophrenia on Wikipedia is generally as good as, or better than, that provided by centrally controlled websites, Encyclopaedia Britannica and a psychiatry textbook.

Molecular genetic differentiation in earthworms inhabiting a heterogeneous Pb-polluted landscape

A Pb-mine site situated on acidic soil, but comprising of Ca-enriched islands around derelict buildings was used to study the spatial pattern of genetic diversity in Lumbricus rubellus. Two distinct genetic lineages ('A' and 'B'), differentiated at both the mitochondrial (mtDNA COII) and nuclear level (AFLPs) were revealed with a mean inter-lineage mtDNA sequence divergence of approximately 13%, indicative of a cryptic species complex. AFLP analysis indicates that lineage A individuals within one central 'ecological island' site are uniquely clustered, with little genetic overlap with lineage A individuals at the two peripheral sites. FTIR microspectroscopy of Pb-sequestering chloragocytes revealed different phosphate profiles in residents of adjacent acidic and calcareous islands. Bioinformatics found over-representation of Ca pathway genes in EST(Pb) libraries. Subsequent sequencing of a Ca-transport gene, SERCA, revealed mutations in the protein's cytosolic domain. We recommend the mandatory genotyping of all individuals prior to field-based ecotoxicological assays, particularly those using discriminating genomic technologies.

As-resistance in laboratory-reared F1, F2 and F3 generation offspring of the earthworm Lumbricus rubellus inhabiting an As-contaminated mine soil

Previous studies provided no unequivocal evidence demonstrating that field populations of Lumbricus rubellus Hoffmeister (1843), exhibit genetically inherited resistance to As-toxicity. In this study F1, F2 and F3 generation offspring derived from adults inhabiting As-contaminated field soil were resistant when exposed to 2000 mg kg(-1) sodium arsenate. The offspring of uncontaminated adults were not As-resistant. Cocoon viability was 80% for F1 and 82% for F2 offspring from As-contaminated adults and 59% in the F1 control population. High energy synchrotron analysis was used to determine whether ligand complexation of As differed in samples of: resistant mine-site adults, the resistant F1 and F2 offspring of the mine-site earthworms exposed to the LC(25) sodium arsenate (700 mg kg(-1)) of the F1 parental generation; and adult L. rubellus from an uncontaminated site exposed to LC(25) concentrations of sodium arsenate (50 mg kg(-1)). XANES and EXAFS indicated that As was present as a sulfur-coordinated species.

Earthworm genomes, genes and proteins: the (re)discovery of Darwin's worms

Small incremental biological change, winnowed by natural selection over geological time scales to produce large consequences, was Darwin's singular insight that revolutionized the life sciences. His publications after 1859, including the ‘earthworm book’, were all written to amplify and support the evolutionary theory presented in the Origin. Darwin was unable to provide a physical basis for the inheritance of favoured traits because of the absence of genetic knowledge that much later led to the ‘modern synthesis’. Mistaken though he was in advocating systemic ‘gemmules’ as agents of inheritance, Darwin was perceptive in seeking to underpin his core vision with concrete factors that both determine the nature of a trait in one generation and convey it to subsequent generations. This brief review evaluates the molecular genetic literature on earthworms published during the last decade, and casts light on the specific aspects of earthworm evolutionary biology that more or less engaged Darwin: (i) biogeography, (ii) species diversity, (iii) local adaptations and (iv) sensitivity. We predict that the current understanding will deepen with the announcement of a draft earthworm genome in Darwin's bicentenary year, 2009. Subsequently, the earthworm may be elevated from the status of a soil sentinel to that elusive entity, an ecologically relevant genetic model organism.

Comparative transcriptomic responses to chronic cadmium, fluoranthene, and atrazine exposure in Lumbricus rubellus

Transcriptional responses of a soil-dwelling organism (the earthworm Lumbricus rubellus) to three chemicals, cadmium (Cd), fluoranthene (FA), and atrazine (AZ), were measured following chronic exposure, with the aim of identifying the nature of any shared transcriptional response. Principal component analysis indicated full or partial separation of control and exposed samples for each compound but not for the composite set of all control and exposed samples. Partial least-squares discriminant analysis allowed separation of the control and exposed samples for each chemical and also for the composite data set, suggesting a common transcriptional response to exposure. Genes identified as changing in expression level (by the least stringent test for significance) following exposure to two chemicals indicated a substantial number of common genes (> 127). The three compound overlapping gene set, however, comprised only 25 genes. We suggest that the low commonality in transcriptional response may be linked to the chronic concentrations (approximately 10% EC50) and chronic duration (28 days) used. Annotations of the three compound overlapping gene set indicated that genes from pathways most often associated with responses to environmental stress, such as heat shock, phase I and II metabolism, antioxidant defense, and cation balance, were not represented. The strongest annotation signature was for genes important in mitochondrial function and energy metabolism.

Translational mini-review series on vaccines: The Edward Jenner Museum and the history of vaccination

Edward Jenner's discovery of vaccination must rank as one of the most important medical advances of all time and is a prominent example of the power of rational enquiry being brought to bear during the Age of Enlightenment in 18th century Europe. In the modern era many millions of lives are saved each year by vaccines that work essentially on the same principles that were established by Edward Jenner more than 200 years ago. His country home in Berkeley, Gloucestershire, is where he carried out his work and where he spent most of his life. The building is now a museum in which the life and times of Jenner are commemorated including not only the discovery of smallpox vaccination but also his other important scientific contributions to natural history and medicine. The trustees of the Edward Jenner museum are committed to promoting the museum as a real and "virtual" educational centre that is both entertaining and informative.

Expression of CXCR6 and its ligand CXCL16 in the lung in health and disease

BACKGROUND

Chemokine receptors (CR) play an important role in T cell migration, but their contribution to lung trafficking is unclear.

OBJECTIVE

We hypothesized that if a particular CR was involved in T cell homing its expression would be enriched on lung T cells compared with peripheral blood T cells (PBT).

METHODS

We have measured the CR expression on BAL T cells from patients with sarcoid, other interstitial lung diseases (ILD), asthma and healthy volunteers.

RESULTS

Of 14 CR studied in sarcoid, CXCR6 expression was the most markedly increased in the lung compared with the blood, a finding that was also seen in ILD patients. A striking although lesser increase was also seen in asthmatics and healthy controls. Analysis of expression of the CXCR6 ligand, CXCL16, by immunohistochemistry suggested that alveolar macrophages (AM) were the major source of CXCL16 in the lung. AM expressed mRNA for CXCL16 and released nanogram quantities after adhesion to plastic as shown by RT-PCR, Western blotting and ELISA. Bronchoalveolar lavage (BAL) fluid from all subjects contained large amounts of CXCL16. The full-length CXCL16 was the predominant isoform in AM lysates, supernatants and BAL.

CONCLUSION

This data suggests that CXCR6 and CXCL16 may play a role in T cell recruitment to the lung.

Quantitative ultrastructure of metal-sequestering cells reflects intersite and interspecies differences in earthworm metal burdens

Morphometric analysis of transmission electron micrographs was used to compare the effects of metals on the multifunctional, metal-sequestering, chloragocyte cells of two epigeic earthworm species, Dendrodrilus rubidus and Lumbricus rubellus, inhabiting three field soils: a clean circumneutral reference soil (Dinas Powys); an acidic moderately Pb- and Zn-contaminated soil (Cwmystwyth); and a calcareous Cd-, Pb-, and Zn-contaminated soil (Draethen). The main findings were: (1) D. rubidus accumulated significantly higher tissue Cd and Pb and lower Zn concentrations than L. rubellus, especially at Draethen; (2) the volume fraction of chloragosomes was significantly lower and the volume fraction of debris vesicles significantly higher in D. rubidus from Draethen compared with L. rubellus at all sites and with the other two D. rubidus populations; (3) estimated relative toxicity factors, derived from soil metal concentrations and published EC50 data, suggested that the subcellular changes in chloragocytes, particularly in D. rubidus from Draethen, were caused mainly by Zn and Pb exposures; (4) scrutiny of the body burdens of each metal in both worm species across the three sites indicated that Cd was a major contributor to the structural changes observed in Draethen D. rubidus, and its impact was disproportionate to its soil and tissue concentrations in comparison with those of Pb and Zn. The apparent greater susceptibility of D. rubidus cells, compared with L. rubellus cells, to soil metal contaminants is discussed in light of differences in the quality and quantity of the metal body burdens accumulated by the two species. Further histopathalogic and morphometric studies on key organs and tissue of earthworms are required to provide biomarkers of exposure and to underpin linkage of biochemical-level changes and demography.

Ligand arsenic complexation and immunoperoxidase detection of metallothionein in the earthworm Lumbricus rubellus inhabiting arsenic-rich soil

Although earthworms have been found to inhabit arsenic-rich soils in the U.K., the mode of arsenic detoxification is currently unknown. Biochemical analyses and subcellular localization studies have indicated that As3+-thiol complexes may be involved; however, it is not known whether arsenic is capable of inducing the expression of metallothionein (MT) in earthworms. The specific aims of this paper were (a) to detect and gain an atomic characterization of ligand complexing by X-ray absorption spectrometry (XAS), and (b) to employ a polyclonal antibody raised against an earthworm MT isoform (w-MT2) to detect and localize the metalloprotein by immunoperoxidase histochemistry in the tissues of earthworms sampled from arsenic-rich soil. Data suggested that the proportion of arsenate to sulfur-bound species varies within specific earthworm tissues. Although some arsenic appeared to be in the form of arsenobetaine, the arsenic within the chlorogogenous tissue was predominantly coordinated with S in the form of -SH groups. This suggests the presence of an As::MT complex. Indeed, MT was detectable with a distinctly localized tissue and cellular distribution. While MT was not detectable in the surface epithelium or in the body wall musculature, immunoperoxidase histochemistry identified the presence of MT in chloragocytes around blood vessels, within the typhlosolar fold, and in the peri-intestinal region. Focal immunostaining was also detectable in a cohort of cells in the intestinal wall. The results of this study support the hypothesis that arsenic induces MT expression and is sequestered by the metalloprotein in certain target cells and tissues.

Responses of earthworms (Lumbricus rubellus) to copper and cadmium as determined by measurement of juvenile traits in a specifically designed test system

In this study, the effects of two metals, copper and cadmium, on the growth and development of juvenile Lumbricus rubellus were measured in a toxicity test in which individuals were grown in isolation. This design had a number of advantages over traditional test systems for earthworms. Importantly, the test is specifically designed to measure two juvenile traits (survival over and length of the juvenile period) that have been shown to have a high sensitivity for determining population growth rate. The test system also maximizes replication, while allowing time-series-based monitoring of individual growth. For both metals, significant exposure-dependent effects on survival, growth, development time, and (less certainly) maturation weight were observed. Comparisons of the relative toxicity of the two metals indicated different concentration-response relationships. For copper, hormesis was found at low levels, while only at the highest soil concentration tested (10.07 micromol g(-1)) were (severe) toxic effects present. For cadmium, hormesis was also evident at the lowest concentration tested; however, at soil levels above this, a graded concentration-dependent toxic effect was apparent. These differences in the exposure response patterns can be (tentatively) explained in terms of the mechanisms for handling copper (an essential metal for earthworms) and cadmium (a putative nonessential element). The applicability of the test for routine measurement of chemical effects on ecologically relevant juvenile traits is also outlined and future developments are discussed.

Measurement of annetocin gene expression: a new reproductive biomarker in earthworm ecotoxicology

The emergence of new technologies from the genomics revolution will transform the potential application of biomarkers to assess how pollutants impact people, animals, and ecosystems. Genetic databases provide a huge resource from which candidate molecular biomarkers can be identified and, subsequently, exploited to address these issues. However, a major challenge is to link these novel molecular indices to ecologically relevant whole-organism life-cycle traits (such as reproduction and growth). Such a functional link is provided by annetocin, previously characterized as a member of the vasopressin/oxytocin superfamily of neuropeptides. It is expressed in annelid worms within the neurons of the central nervous system and has been shown to be involved in the induction of egg-laying behavior. This paper outlines the validation of annetocin as a novel biomarker of reproductive fitness in the earthworm Eisenia fetida. The design of primer pairs targeted toward oligochaete annetocin has facilitated the isolation of a full-length annetocin cDNA from this species. Optimization of a real-time quantitative PCR procedure exploiting the fluorescent DNA-binding molecule, Sybr Green, has allowed the measurement of annetocin transcript levels over a range covering six orders of magnitude. Using this approach, gene expression was measured in earthworms exposed to soils polluted with high concentrations of zinc and lead. Traditional growth and reproductive indices, including cocoon production, were also recorded and related to the molecular parameter. The future use of annetocin as a molecular genetic biomarker in terrestrial ecotoxicology is discussed.

Differential metallothionein expression in earthworm (Lumbricus rubellus) tissues

This article describes the immunoperoxidase localization of metallothionein (MT) in the major organs and tissues of the earthworm Lumbricus rubellus sampled from a mine soil heavily polluted with Pb, Zn, and Cd. The polyclonal antiserum used was raised against the MT isoform (wMT2), the molecular characteristics and focal subcellular distribution of which indicate a primary role for it in the sequestration of certain nonessential metals, such as Cd. Intense MT immunostaining was detectable in chloragogenous tissue throughout the body: around the intestine, in the typhlosolar infolding, around blood vessels anterior and posterior to the crop/gizzard, and around the calciferous gland. Electron probe X-ray microanalysis of neutral red-labeled vesicular structures in the chloragogenous tissue indicated that this acidic compartment, probably lysosomal, yielded the strong Cd and S signals associated with Cd-MT. MT expression was also detected in the apical cytoplasm of intestinal epithelial cells; in coelomocytes contiguous with chloragocytes attached to the gut; within the narrow tubular region of nephridia, in the secretory epithelia of the calciferous gland, but not anywhere in the body wall. We concluded that (a) the main route of Cd uptake is probably via absorptive alimentary surfaces, and not across the external epidermal layer; (b) nephridia are involved with Cd excretion and/or are a major target of Cd-induced pathological damage; (c) tentatively, a combination of immunohistochemistry and proton-induced X-ray emission analysis indicated that the calciferous gland is probably not a major "heavy metal" excretory route.

Respiratory symptoms in patients with treated hypothyroidism and inflammatory bowel disease

BACKGROUND

Patients with idiopathic chronic cough and unexplained airflow obstruction in non-smokers have been shown to have an increased prevalence of hypothyroidism and other organ specific autoimmune disorders. Whether patients with hypothyroidism have an increased prevalence of respiratory symptoms is unknown.

METHODS

The prevalence of respiratory symptoms was assessed in 124 patients with treated hypothyroidism recruited from primary and secondary care, 64 outpatients with inflammatory bowel disease, and 1346 control adults recruited randomly from the electoral register in a case-control study. Respiratory symptoms and smoking history were assessed by a respiratory symptom questionnaire.

RESULTS

After adjustment for age, sex and smoking, symptoms of breathlessness and sputum production were more prevalent in both patient populations than in controls (odds ratios for hypothyroidism and inflammatory bowel disease; breathlessness: 3.1 (95% CI 2.1 to 4.6) and 3.4 (95% CI 2.0 to 6.0), respectively; sputum production: 2.7 (95% CI 1.6 to 4.5) and 2.5 (95% CI 1.2 to 5.0), respectively). Cough during the day and night was significantly more prevalent in patients with hypothyroidism (1.8 (95% CI 1.2 to 2.9)) and approached significance in those with inflammatory bowel disease (1.8 (95% CI 1.0 to 3.4)). Wheeze and nocturnal cough were no more prevalent in either disease population than in controls.

CONCLUSION

There is a significantly increased prevalence of respiratory symptoms in patients with hypothyroidism or inflammatory bowel disease compared with controls recruited from the general population. Further work is required to determine whether similar differences are seen in comparison with hospital based controls. These findings support the hypothesis that there is a link between autoimmune hypothyroidism and respiratory disease.

Developing a new method for soil pollution monitoring using molecular genetic biomarkers

Physiological responses to environmental stressors may induce changes in gene expression as part of an organism's homeostatic mechanisms. Thus molecular genetic biomarkers have the potential to be used for monitoring sublethal chemical exposure in ecosystems. This paper describes a methodological assessment of the suitability of a protocol to monitor selected biomarkers. The TaqMan real-time quantitative polymerase chain reaction was used to measure gene transcription in earthworms (Lumbricus rubellus) maintained on control or cadmium- or copper-spiked soil. Changes in the expression of two target genes, that encoding metallothionein isoform 2 (MT-2) and that encoding the mitochondrial large ribosomal subunit (MLRS), were quantified against the internal control gene beta-actin. The protocol used produced reliable and reproducible results. Transcript levels displayed qualitative and quantitative differences in the responses to the two metal ions. MLRS gene levels were unaffected by exposure to cadmium but displayed a response to high levels of copper. Conversely, cadmium greatly induced MT-2 gene expression, but copper only altered transcription of this gene at high exposure concentrations. This study demonstrates that it is now technically feasible to use gene expression as an index of pollution exposure in environmentally relevant organisms.

Subcellular distribution of cadmium and its cellular ligands in mussel digestive gland cells as revealed by combined autometallography and X-ray microprobe analysis

Autometallography (AMG) and electron probe X-ray microanalysis (EPXMA) were applied in combination to determine the subcellular distribution of Cd and its subcellular ligands in the digestive gland cells of Cd-exposed mussels Mytilus galloprovincialis. Black silver deposits (BSD), which reveal the presence of metals when AMG is applied, were only localized in digestive cell lysosomes. Digestive cell cytoplasm and basophilic cells were devoid of BSD. EPXMA (static probe and X-ray mapping) indicated that Cd, S (possibly associated with metallothioneins or metallothionein-like proteins) and autometallographical Ag ions are co-localized within digestive cell lysosomes. In addition, Cd and S co-occur in the absence of Ag in the cytosol of digestive cells. AMG does not reveal the presence of the Cd 'pool' strongly bound to cytosolic Cd-metallothionein complexes; only 'free' Cd or Cd supposedly loosely bound to (semi)digested metallothionein within lysosomes was revealed. The levels of lysosomal Cd were indirectly quantified by stereology as the volume density of BSD (V(v)BSD). Significantly higher values were recorded in Cd-exposed mussels compared with controls at all exposure times. However, V(v)BSD values were lower at days 7 and 21 than at day 1. This relative decrease in V(v)BSD reflected another (and confounding) response elicited by Cd-exposure in the digestive epithelium: the volume density of basophilic cells (V(v)BAS) increased significantly as exposure progressed. Due to this cell-type replacement, the net accumulative capacity of the digestive epithelium decreases at long exposure times.

In vitro cytokine production and growth inhibition of lymphoblastoid cell lines by CD4+ T cells from Epstein-Barr virus (EBV) seropositive donors

In vitro stimulation of peripheral blood lymphocytes (PBL) from healthy Epstein-Barr Virus (EBV) seropositive individuals with autologous lymphoblastoid cell lines (LCL) gives rise to CD4+ and CD8+ T cells both of which are cytotoxic for autologous lymphoblastoid cells. Activated EBV-specific CD4+ T cells are cytotoxic towards autologous LCL but, paradoxically, CD4+ T cells have also been shown to enhance tumour formation in SCID/Hu mice. Here, we show that despite being cytotoxic, CD4+ T-cell lines from different donors show considerable variation in their ability to inhibit the long-term growth of autologous LCLs in vitro. Following re-stimulation in vitro with PMA and ionomycin, CD4+ T cells produced IFNgamma, TNFalpha, TNFbeta, IL-2, IL-4, IL-10 and IL-13. TNFalpha, TNFbeta and IL-10 production were also detected in LCL. IL-6 was only detected in trace amounts in either cell type. The ratio of IFNgamma to IL-4 production varied between the CD4+ T-cell lines, indicating differences in the Th1/Th2 balance of the response. When CD4+ T cells were re-stimulated using autologous LCL as antigen-presenting cells, they produced more IL-4 and less IFNgamma or IL-13 when compared with cells re-stimulated by phorbol myristate acetate (PMA) and ionomycin. Using two colour cytokine staining, we showed that many individual CD4+ T cells produced IFNgamma along with either IL-4 or IL-13. Purified CD4+ T cells completely inhibited the outgrowth of autologous LCL in five out of nine cases, and partially inhibited outgrowth in the remaining four. There was no correlation between the pattern of CD4+ T-cell cytokine production and the capacity to inhibit outgrowth of autologous LCL. The killing of LCLs was contact-dependant and not mediated by soluble factors. We conclude that the ability of CD4+ T cells to inhibit autologous LCL growth is not directly related to T-helper cell cytokine production, but may depend on cytoxicity through surface ligands such as CD95L (FasL) and TNFalpha-related apoptosis-inducing ligand (TRAIL).

Metal ion trafficking in earthworms. Identification of a cadmium-specific metallothionein

Exposure to cadmium poses a considerable risk to human health and environmental safety. Earthworms reside in the most contaminated sites on earth, displaying a phenomenal tolerance to toxic heavy metals. They exhibit a distinct metabolic pathway that allows the bio-accumulation of cadmium to yield body burdens in excess of 1/1000th of total dry body weight, a most impressive figure by any standard. However, the precise molecular mechanism underlying this phenomenon remains to be unraveled. This study meets this challenge by fully characterizing the major metal-binding protein in earthworms, namely the two isoforms of metallothionein. Chemical analysis of recombinant protein showed that although both isoforms bind equimolar amounts of cadmium (6 mol), wMT-2 is more stable during proton competition. Furthermore, isoform-specific transcript analysis demonstrated that only wMT-2 is responsive to cadmium in a dose and temporal manner. The specific sequestration of cadmium to wMT-2 protein was confirmed in situ using polyclonal antisera. The latter also provided the means for mapping the cellular and intracellular distribution of metallothionein, thus yielding a holistic insight into its involvement in cadmium transit during absorption, storage, and excretion. The structure-function relationship of wMT-2 and its role in cadmium detoxification through sequestration and compartmentalization is discussed.

Earthworm pre-procarboxypeptidase: a copper responsive enzyme

This paper describes the identification and molecular cloning of the earthworm metalloenzyme preprocarboxypeptidase. It was possible to approximate the putative pre-pro cleavage sites, which after removal activates a 35.7 kDa mature peptide with a length of 317 amino acids. The primary, secondary and predicted tertiary structure of the mature chain is highly homologous to other carboxypeptidases from diverse phylogenetic origin. Using a fully quantitative PCR, we were able to assess relative expression of this gene in earthworms exposed to different heavy metal contaminated substrates. In summary, cadmium on its own or in combination with lead and zinc, did not trigger transcriptional up-regulation of carboxypeptidase. In contrast, copper exposed earthworms were assessed to have a 4-fold increase in carboxypeptidase transcript numbers. A hypothetical model is presented to explain how the exposure to heavy metals may influence transcriptional control and/or function of this enzyme. Finally, the significance of these observations in terms of risk assessment and biomonitoring of contaminated soils is discussed.

Stable strontium accumulation by earthworms: a paradigm for radiostrontium interactions with its cationic analogue, calcium

The accumulation of stable strontium and its chemical analogue calcium by four species of earthworm, representing three distinct ecophysiological groups inhabiting celestite (SrSO4)-rich natural soils, was investigated. An increase in soil strontium concentration over a four-orders-of-magnitude range was accompanied by an increase in earthworm tissue strontium concentration. In contrast, no relationship between soil and tissue calcium concentrations was apparent, indicating that this essential cation is strongly regulated within earthworm tissues but that nonessential strontium burdens are not physiologically regulated. Concentration factors for strontium ranged from 0.1 to 1.42, with an inverse relationship between this parameter and soil strontium concentration. The use of concentration factors and discrimination coefficients lead to the conclusion that earthworms discriminate against strontium accumulation at increased soil calcium concentrations, such that strontium would be predicted to be more efficiently accumulated by worms inhabiting acidic, calcium-poor soils. Although few consistent trends in strontium and calcium concentration were apparent between earthworm species, the species with the highest calcium turnover (i.e., the litter-inhabiting Lumbricus rubellus) typically accumulated higher concentrations of strontium than representatives of contrasting ecophysiological classes. These findings are considered in the context of the distribution, retention, and cycling of radiostrontium in soils.

An asymmetric aminohydroxylation approach to the azepine core of (-)-balanol

[reaction: see text]An efficient formal synthesis of the potent protein kinase C inhibitor (-)-balanol that relies on a modified asymmetric aminohydroxylation of the alpha,beta-unsaturated aryl ester (1) is reported. The aryl ester functionality and the dihydroquinyl alkaloid ligand system (DHQ)2-AQN are used to control the regio- and enantioselectivity of the process.

Characterisation and quantification of earthworm cyclophilins: identification of invariant and heavy metal responsive isoforms

We report the identification of two earthworm cyclophilin genes, which resemble the cytosolic cyclophilin-A and the signal sequence containing cyclophilin-B. Using fully quantitative PCR we were able to assess the transcript regulation of both cyclophilin isoforms, as well as a further independent control gene (actin), during exposure to heavy metals. Whilst the expression of cyclophilin-B and actin remained exceptionally constant, cyclophilin-A was up-regulated 38-fold. This intriguing observation has profound implications regarding cyclophilin's use as an invariant control and highlights the fact that it is essential to treat cyclophilin isoforms as separate entities, rather than one functional unit.

Reversal of regioselection in the sharpless asymmetric aminohydroxylation of aryl ester substrates

[formula: see text] The asymmetric synthesis of beta-hydroxy-alpha-amino acids is reported which relies on the use of alpha,beta-unsaturated aryl ester substrates and the dihydroquinyl alkaloid ligand system (DHQ)2-AQN to control the regio- and enantioselectivity of the asymmetric aminohydroxylation (AA) process. alpha,beta-Unsaturated ester substrates of type 1 have a significant effect on the substrate-ligand recognition event which results in a reversal of regioselectivity in the AA reaction.

The major Epstein-Barr virus (EBV) envelope glycoprotein gp340 when incorporated into Iscoms primes cytotoxic T-cell responses directed against EBV lymphoblastoid cell lines

A recombinant form of the EBV envelope glycoprotein and vaccine candidate gp340, lacking its hydrophobic transmembrane region, was incorporated into Iscoms after coupling to phosphatidyl ethanolamine via carbohydrate residues. Coupling by partial oxidation of gp340 carbohydrate with sodium periodate partly denatured the incorporated gp340 as indicated by its reduced reactivity with monoclonal antibodies that recognise the major neutralising epitope. Immunisation of cottontop tamarins with these Iscoms elicited antibody responses to gp340, but these antibodies only poorly recognised the major neutralising epitope in a competition ELISA and were unable to neutralise EBV in vitro. Despite the lack of neutralising antibody, immunisation with these Iscoms primed significant in vitro proliferative responses to soluble gp340 in lymphocytes from the draining lymph nodes and spleen. T-cell lines were raised from both immunised and control animals by in vitro stimulation of peripheral blood lymphocytes or spleen cells with autologous EBV-transformed lymphoblastoid cell lines. The T-cell lines from control animals had higher numbers of CD4+ T-cells than CD8+ T-cells and were not cytotoxic for autologous lymphoblastoid cell lines (LCL). In contrast the lines from immunised animals contained more CD8+ T-cells than CD4+ T-cells and had marked cytotoxicity for autologous LCL.

Differential modulation of the phases of a Ca2+ spike by the store Ca2+-ATPase in human umbilical vein endothelial cells

1. Histamine-stimulated cytosolic free Ca2+ ([Ca2+]i) oscillations in human umbilical vein endothelial cells (HUVECs) comprise repetitive spikes generated by pulsatile release from stores. We have investigated the roles of the store Ca2+-ATPases in regulating both the upstroke and downstroke of a Ca2+ spike. 2. The sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor cyclopiazonic acid (CPA) dramatically affected oscillations whereas inhibition of the plasma membrane Ca2+-ATPase (PMCA) with La3+ had little effect. This and other evidence suggested that the downstroke of a spike is predominantly mediated by SERCA. 3. Artificial [Ca2+]i spiking generated by repetitive pulsatile application of 0.3 microM histamine in Ca2+-free medium did not cause net loss of Ca2+ from the cell whereas repetitive pulsatile application of 1 and 10 microM histamine did, with the higher concentration being more effective. We conclude that there is an inverse relationship between stimulus intensity and relative SERCA activity. 4. For a Ca2+ transient, the initiation of release was suppressed by SERCA during either the lag phase or the interspike period (ISP) since: (i) the ISP was shortened by low CPA concentrations, (ii) higher concentrations of CPA stimulated an explosive Ca2+ release when applied during the ISP but not when applied in the absence of agonist, and (iii) CPA synchronized the initial Ca2+ response to a low histamine dose (even recruiting silent, histamine-unresponsive cells). 5. Two aspects of the regenerative upstroke of a spike were differently affected by SERCA inhibition: Ca2+ wave velocity was entirely unaffected by CPA whereas the local rate of rise was increased. 6. The [Ca2+]i at which a Ca2+ spike terminated depended on SERCA since CPA dose dependently enhanced the peak [Ca2+]i. 7. We conclude that SERCA plays a powerful and dynamic role in regulating [Ca2+]i oscillations in HUVECs. SERCA differentially modulates the phases of Ca2+ release in addition to bringing about the falling phase of a Ca2+ spike.

CD4+ T cells inhibit growth of Epstein-Barr virus-transformed B cells through CD95-CD95 ligand-mediated apoptosis

Greater than 90% of the human population acquire Epstein-Barr virus (EBV) in infancy and retain a lifelong latent infection without any clinical consequences. Nevertheless EBV has been identified as the causal agent of infectious mononucleosis, and is associated with several tumours including endemic Burkitt's lymphoma and B cell lymphomas in immunosupressed patients. B cells infected with EBV are transformed in vitro and grow continuously as lymphoblastoid cell lines. The growth of EBV-transformed B cells in vivo is controlled by the immune system. Studies on immunity to EBV have mainly focused on MHC class I-restricted CD8+ cytotoxic T cells specific for viral latent antigens. Here it is reported that in vitro stimulation of peripheral blood lymphocytes by autologous EBV-infected B cells, which have been induced to express lytic cycle antigens, gives rise to a predominantly CD4+ T cell response. Furthermore, the growth of EBV-infected B cells can also be regulated by these activated CD4+ T cells through apoptosis mediated by CD95-CD95 ligand (CD95L). CD95-CD95L-mediated apoptosis is an important mechanism of normal B cell growth regulation. As EBV-transformed B cells remain susceptible to this mechanism, the control of EBV in vivo may be not only by virus-specific CD8+ cytotoxic T cell immunity but also by normal mechanisms of immune regulation of B cell growth.

Cu-Cd interactions in earthworms maintained in laboratory microcosms: the examination of a putative copper paradox

Earthworms (Lumbricus rubellus) from Ecton (predominantly Cu-contaminated), Shipham (Cd-contaminated) and Dinas Powys (uncontaminated, reference) were maintained in the laboratory on soil from the sampling sites. Two principle exposure protocols were used: (1) a 4-week 'no pre-exposure experiment', where batches of earthworms were maintained on soils from each habitat and (2) a 'pre-exposure experiment' where uncontaminated control worms were maintained on Shipham soil for 4 weeks (the pre-exposure period), and then transferred to Ecton soil for a further 4 weeks, and vice versa. In summary, there were two primary findings. Firstly, exposure of worms to Cd-rich soil (Shipham) before exposure to Cu-rich soil (Ecton) increased the Cu burden and secondly, biochemical analysis of metal binding proteins in analogous earthworm populations indicated that Cu and Cd, but not Zn, are bound to a metallothionein homologue. These observations are consistent with the hypothesis that Cu does not induce thionein synthesis efficiently in earthworm tissues, but may bind avidly to Cd-induced thionein by substituting for Cd in the molecule because Cu-thionein is a more stable complex.

The identification, cloning and characterization of earthworm metallothionein

Combining standard gel chromatographic techniques and novel molecular methodologies (Directed Differential Display and quantitative PCR), it has been possible to isolate and sequence two isoforms of the first true earthworm metallothionein. Both proteins are characteristically high in cysteine residues and possess no significant aromatic residues. Metal responsiveness was confirmed by determining metallothionein specific expression profiles in earthworms exposed to soils of differing heavy metal concentrations. Analysis of the derived amino acid sequence of isoform 2 identified two putative N-glycosylation signal sequences, suggesting that the two isoforms may have different subcellular distributions and functions. Possible implications for intracellular metal trafficking are discussed.

Identification of heavy metal induced changes in the expression patterns of the translationally controlled tumour protein (TCTP) in the earthworm Lumbricus rubellus1

Heavy metal contaminated soils are assessed for specific human health and ecological risk by governmental regulatory agencies utilizing the abundant soil invertebrate, the earthworm, in a biomonitoring process. Fingerprinting the molecular genetic responses resulting from heavy metal exposure facilitates the identification of biomarkers for assessing the impact of such pollution on individual organisms. This paper reports the identification of a novel translationally controlled tumour protein (TCTP) in the earthworm Lumbricus rubellus. In addition to the standard molecular biological technique of differential Southern blotting, a fully quantitative approach (fluorescent microvolume PCR) was performed to assess the specific expression profiles of TCTP in earthworms exposed to different heavy metal regimes. After normalizing with actin as an invariant control, the results showed that TCTP was upregulated by at least a factor of 4 in the population originating from a Pb/Zn/Cd polluted mine, compared to an unpolluted control population. An even more pronounced increase was identified in earthworms native to a Cu polluted mine, where TCTP increased 335-fold. TCTP copies in earthworms exposed to artificial soil with a single stressor (Cd) were 14 times higher than in the appropriate control earthworms (maintained on artificial soil without Cd). The data presented are novel in two ways: first, they provide evidence for an upregulation that is induced by heavy metals (especially copper); second, they show that TCTP can also be under transcriptional control, therefore upregulation is not limited to translational modifications as TCTP's nomenclature suggests.

Indirect measurement of Epstein-Barr virus neutralising antibodies by ELISA

A rapid and effective ELISA for measuring Epstein-Barr virus (EBV)-neutralizing antibodies in human sera was devised to replace the existing cumbersome method involving the inhibition of fetal cord blood B-cell transformation by the virus. The new method will be invaluable for assessing antibody responses in human subjects participating in EBV gp340 vaccine trials. The ELISA developed uses the human serum antibody to be tested to inhibit standardised binding of an EBV-neutralizing monoclonal antibody (mAb) to gp340 itself or its recombinant derivatives. A serum which has high EBV-neutralizing antibody titres inhibits the binding of neutralizing mAb to gp340 more than a serum with low levels. EBV neutralisation antibody titres obtained by the new inhibition ELISA correlate well with values obtained using the lengthy conventional assay where inhibition of B-cell transformation is assessed. The new assay can be carried out in a few hours compared to 4-5 weeks for the conventional test and could be automated for processing very large sample numbers in vaccine trials.

The distribution and intracellular compartmentation of metals in the endogeic earthworm Aporrectodea caliginosa sampled from an unpolluted and a metal-contaminated site

The tissue distribution of Cd, Cu, Pb, Zn and Ca in the endogeic earthworm Aporrectodea caliginosa living in a non-polluted and a heavy metal polluted soil was investigated. The tissues of animals from the contaminated soil contained greater concentrations of Cd, Pb and Zn than the corresponding tissues of animals from the unpolluted soil. The greatest concentrations of Cd, Pb, Zn, and Ca were primarily accumulated within the posterior alimentary canal (PAC), a tissue fraction which contained the greatest proportion of the whole-worm burdens of the respective metals. Cu was distributed fairly evenly in the tissue fractions investigated. The pattern of accumulation for the 'heavy' metals is broadly similar to that for epigeic earthworms; in contrast, a different pattern of tissue accumulation was found for Ca. In animals from the uncontaminated site, the major elemental constituents of the chloragosomes were P, Ca, Zn and S. A significant positive correlation exists between P and Ca within the chloragosomal matrix. These intracellular vesicles are major foci for Pb and Zn accumulation within the PAC, with 'excess' metals associated with P ligands within the chloragosome matrix. The incorporation of Pb and Zn appears to involve the cationic displacement of Ca. Such compartmentation appears to prevent dissemination of large concentrations of these metals into other earthworm tissues, and may thus represent a detoxification strategy based on accumulative immobilization. No intracellular localization of Cd was identified in the study, although the Cd concentration in the metalliferous soils examined was not exceptionally high. The observations are discussed in the context of a contribution to enhanced understanding of metal ecotoxicology in earthworms by providing baseline data on a little investigated ecophysiological group of earthworms. Comparisons of metal distribution and mechanisms of metal sequestration are made with other ecophysiological groups of earthworms, and the significance of the findings to biomonitoring and toxicity-testing programmes is considered.

Lack of susceptibility of the cottontop tamarin to hepatitis C infection

The only species apart from man that is known to be susceptible to HCV infection is the chimpanzee but the availability of this primate for research is strictly limited. In an attempt to find an alternative and more practical model for HCV studies three cottontop tamarins were inoculated intravenously with HCV-containing serum from patients with chronic HCV infection. The tamarins were monitored regularly for biochemical indications of hepatic inflammation and serum samples were assayed at weekly intervals for the presence of HCV-RNA and HCV antibodies. HCV-RNA was detectable at 10 minutes postinoculation in all three animals but not at any later time point over a 6 month period. No evidence of an active humoral immune response to the inoculated HCV was obtained although passively transferred anti-HCV was detectable in one animal until 1 week postinoculation. Biochemical findings did not indicate hepatic inflammation and liver histology remained normal. It is concluded on the basis of these negative findings that the cottontop tamarin is not susceptible to HCV infection.

Immunocytochemical identification of metallothionein-positive cells in rheumatoid synovium and analysis of their cell lineage

Metallothionein is a ubiquitous low molecular weight metalloprotein with powerful protective properties against oxygen radical-mediated cytotoxicity associated with inflammatory processes. In rheumatoid arthritis, the inflammatory damage to the synovium appears to be mediated by free radicals released by the high concentration of neutrophils found in the synovial fluid of the inflamed joint. Synovial tissue obtained during routine surgery on rheumatoid and non-rheumatoid joints was subjected to an indirect immunoperoxidase protocol for the immunolocalization of metallothionein using mouse monoclonal anti-metallothionein antibody E9, reactive against the two major isoforms of mammalian metallothionein. A layer of large dendritic-like cells situated subsynovially in the rheumatoid synovium stained very positively for the metalloprotein, both cytoplasmically and in their nuclei. These cells were not found in non-rheumatoid osteoarthritic or in undamaged synovial tissue associated with traumatic joint injury. An attempt was made to investigate their lineage using a series of antibody markers against epithelial cells, endothelial cells, smooth muscle, mesothelial cells, fibroblasts, neutrophils, dermal dendrocytes, macrophages, low and high molecular weight cytokeratin as well as a cell proliferation marker. From our results, it is suggested that these metallothionein-positive cells are probably myofibroblasts similar to the highly motile cells present in granulation tissue. They may originate from perivascular areas of synovium and their movement into the inflamed synovium may reflect the cytoprotective role of metallothionein acting as a free radical scavenger against oxidative damage.

Immunomodulation by Quillaja saponaria adjuvant formulations: in vivo stimulation of interleukin 12 and its effects on the antibody response

The capacity of adjuvants to activate Ag-presenting cells during the induction of the primary immune response is of critical importance for the development of protective immunity to a number of pathogens. In this context, interleukin 12 (IL-12) has a key role by controlling the differentiation of T helper cells and favouring the expansion of Th1 cells. The capacity of iscoms with influenza virus Ag (flu-iscoms) and iscom matrix with EBV gp340 Ag to induce IL-12 was analysed in mice. The flu-iscom drives the immune response towards a Th1 type subsequent to IL-12 induction as measured in the serum of H2b, H2d and H2k mice. The iscom presenting the Ag and adjuvant in the same particle was considerably more efficient than the formulation of matrix and Ag in separate particles. Inhibition experiments with mAb neutralizing IL-12, interferon gamma (IFN-gamma) or IL-4, the latter two cytokines representing the Th1 and Th2 type of responses, showed that iscoms induce a broader immune response than that involving IL-12. This was shown by the additional effect that IL-4 neutralization had on the immune response to iscoms. Anti-IL 12 reduced the specific total Ab as well as IgG1, IgG2a and IgG2b while anti-IL 4 influenced the response to iscom by decreasing IgG2a and increasing IgG1. Further, the neutralization experiments indicate that IL-12 has a broader effect than IFN-gamma on the Ab response by influencing the production of IgG1, IgG2a and IgG2b.

Ca2+ influx does more than provide releasable Ca2+ to maintain repetitive spiking in human umbilical vein endothelial cells

We investigated why oscillations of intracellular Ca2+ concentrations ([Ca2+]i) in endothelial cells challenged by sub-maximal histamine run down in Ca(2+)-free medium despite stores retaining most of their Ca2+. One explantation is that only a small subpopulation of the Ca2+ stores oscillate and are completely emptied of Ca2+. To investigate if influx refills an empty store subpopulation, we differentiated between cations entering the cell and those released from internal stores by using extracellular Sr2+ as a Ca2+ surrogate; we distinguished between [Sr2+]i and [Ca2+]i by using the larger effect of Sr2+ on fura 2 fluorescence at 360 nm (F360). Ca2+ was still available for release when oscillations had run down since oscillations promptly reappeared on addition of Sr2+o and these were predominantly of Ca2+ (indicated by F360 changes). Also, totally depleting Ca2+ stores inhibited Sr(2+)-induced oscillations, suggesting that Sr2+ entry leads to Ca2+ release. In contrast, Ba2+o was unable to stimulate oscillations. Finally, oscillations generated by photolytic release of inositol trisphosphate (IP3) analogues were similarly sensitive to extracellular Ca2+ and Sr2+. We conclude that stores (or a sub-population) are not completely depleted of Ca2+ when oscillations run down in Ca(2+)-free medium. Bivalent cation entry therefore maintains sensitivity to IP3, possibly by maintaining luminal bivalent cation levels.

Increased small intestinal fermentation is partly responsible for the anti-nutritive activity of non-starch polysaccharides in chickens

1. The mechanism of the anti-nutritive activities of soluble non-starch polysaccharides (NSPs) in broiler diets was investigated with emphasis on the inter-relationship between viscosity and fermentation along the gut. Isolated soluble NSP were added to a control diet to effect high gut viscosity, and in vivo depolymerisation of the NSP was achieved using a commercial glycanase. 2. Addition of soluble NSPs significantly (P < 0.01) increased gut viscosity, reduced the AME of the diet and depressed the growth and FCE of the birds. Enzyme supplementation of the NSP-enriched diet reversed the adverse effects, increasing (P < 0.01) weight gain, FCE and AME. Comparisons of the viscosities (mPa) in birds fed on the NSP-enriched diet and the same diet supplemented with enzyme were respectively: 11.9 v. 2.3 in the duodenum; 78.3 v. 4.4 in the jejunum and 409.3 v. 10.8 in the ileum. 3. Caecal volatile fatty acid concentration was markedly (P < 0.01) elevated by enzyme supplementation, whereas ileal fermentation was inhibited. 4. Microscopic examination revealed that, among birds fed on the NSP-enriched diet, there had been extensive small intestinal fermentation, which was eliminated by the enzyme supplementation. 5. Addition of a synthetic antibiotic (Amoxil) had no beneficial effects. 6. The current study demonstrated that increased fermentation occurs in the small intestine when a large amount of viscous NSPs is present in the diet and this is detrimental to the performance and well-being of poultry.

Protein tyrosine kinases regulate agonist-stimulated prostacyclin release but not von Willebrand factor secretion from human umbilical vein endothelial cells

The rapid synthesis and release of prostacyclin (PGI2) and the exocytotic secretion of von Willebrand Factor (vWF) elicited by activation of G-protein-coupled receptors on endothelium occur via signaling mechanisms which are incompletely defined. Activation of protein tyrosine kinases (PTKs) and modulation of the tyrosine-phosphorylation state of endogenous proteins have been implicated in several cellular processes including arachidonate release and exocytosis. In the present study we have examined the regulatory role of PTKs in agonist-stimulated release of PGI2 and vWF from human umbilical vein endothelial cells (HUVECs) using two chemically and mechanistically dissimilar PTK inhibitors (genistein and ST271). Genistein, but not the less active analogue daidzein, dose-dependently attenuated PGI2 release in response to thrombin and histamine (IC50 approx. 20 microM), and to the thrombin-receptor-activating peptide. A more potent inhibition of thrombin- and histamine-induced PGI2 synthesis was observed in cells exposed to ST271. In contrast, neither genistein nor ST271 modulated agonist-drive vWF secretion. At concentrations that abolished PGI2 release, genistein blocked thrombin- or histamine-evoked tyrosine phosphorylation of a 42 kDa protein. Ca2+ ionophore-induced PGI2 generation, but not vWF secretion, was also inhibited by both genistein and ST271, suggesting that these agents modulate PGI2 synthesis by acting at, or distal to, agonist-induced changes in intracellular CA2+ ([Ca2+]i). In fura-2-loaded HUVECs genistein partially reduced the histamine-induced peak [Ca2+]i but had no effect on the thrombin response. Ca(2+)-induced PGI2 release from electrically permeabilized HUVECs was abolished in the presence of ST271 or genistein, but not diadzein. The generation of PGI2 in response to exogenous arachidonic acid was not modulated by genistein or ST271, suggesting that PTK inhibitors do not directly inhibit cyclo-oxygenase activity. Taken together, these results suggest that PTKs regulate PGI2 synthesis and release in HUVECs by modulating, directly or indirectly, a CA(2+)-sensitive step upstream of cyclo-oxygenase.