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This paper considers the analysis of process networks with bottlenecks and shows how they may be regarded as simple multi-source maximal flow linear programming problems. We surveyed over 30 Production/Operations Management and management science/OR textbooks, finding that only iterative trial-and-error procedures are now being suggested for this kind of analysis. The maximal flow network approach is easier for complex problems and also allows several advantages not available in the trial-and-error approaches. This paper also discusses the use of a simple linear programming sensitivity result called radial change. The modelling approach suggested here can provide new ideas for improving system capacity following the application of Theory of Constraints techniques. Keywords: theory of constraints; capacity decisions; linear programming; sensitivity analysis; radial change

Pseudogymnoascus destructans, the fungus that causes white-nose syndrome in hibernating bats, has spread across eastern North America over the past decade and decimated bat populations. The saprotrophic growth of P. destructans may help to perpetuate the white-nose syndrome epidemic, and recent model predictions suggest that sufficiently reducing the environmental growth of P. destructans could help mitigate or prevent white-nose syndrome-associated bat colony collapse. In this study, we screened 301 microbes from diverse environmental samples for their ability to inhibit the growth of P. destructans. We identified 145 antagonistic isolates, 53 of which completely or nearly completely inhibited the growth of P. destructans in co-culture. Further analysis of our best antagonists indicated that these microbes have different modes of action and may have some specificity in inhibiting P. destructans. The results suggest that naturally-occurring microbes and/or their metabolites may be considered further as candidates to ameliorate bat colony collapse due to P. destructans.

Novel species of microfungi described in the present study include the following from Australia: Bagadiella victoriae and Bagadiella koalae on Eucalyptus spp., Catenulostroma eucalyptorum on Eucalyptus laevopinea, Cercospora eremochloae on Eremochloa bimaculata, Devriesia queenslandica on Scaevola taccada, Diaporthe musigena on Musa sp., Diaporthe acaciigena on Acacia retinodes, Leptoxyphium kurandae on Eucalyptus sp., Neofusicoccum grevilleae on Grevillea aurea, Phytophthora fluvialis from water in native bushland, Pseudocercospora cyathicola on Cyathea australis, and Teratosphaeria mareebensis on Eucalyptus sp. Other species include Passalora leptophlebiae on Eucalyptus leptophlebia (Brazil), Exophiala tremulae on Populus tremuloides and Dictyosporium stellatum from submerged wood (Canada), Mycosphaerella valgourgensis on Yucca sp. (France), Sclerostagonospora cycadis on Cycas revoluta (Japan), Rachicladosporium pini on Pinus monophylla (Netherlands), Mycosphaerella wachendorfiae on Wachendorfia thyrsifolia and Diaporthe rhusicola on Rhus pendulina (South Africa). Novel genera of hyphomycetes include Noosia banksiae on Banksia aemula (Australia), Utrechtiana cibiessia on Phragmites australis (Netherlands), and Funbolia dimorpha on blackened stem bark of an unidentified tree (USA). Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Interferon-gamma (IFNgamma) gene expression is tightly regulated in early life, and exaggerated negative control of IFNgamma production in CD4(+) T cells has been associated with risk for subsequent development of atopy. Recent studies have demonstrated hypermethylation of CpG sites in the IFNgamma promoter in neonates, a mechanism which in mice leads to strong suppression of IFNgamma gene transcription. In the present study, the methylation status of six CpG sites in the proximal promoter of the human IFNgamma gene was determined by bisulphite sequencing. Cell populations studied were Th1 or Th2 polarized cell lines derived from neonatal and adult CD4(+)/CD45RA(+) T cells, CD4(+) and CD8(+) naive T cells from cord blood of children followed to outcome age 2 for assessment of atopy status, and CD4(+) and CD8(+) naive T cells from 6 yr old and adult atopics and controls. We demonstrate that in vitro differentiation of CD4(+) T cells down the Th1 pathway (but not the Th2 pathway) is accompanied by progressive demethylation of CpG sites in the IFNgamma promoter, which is most marked in neonatal cells. Atopy development by age 2 was not associated with variations in methylation patterns in cord blood T cells. However, IFNgamma promoter methylation was reduced in CD8(+) T cells from atopic children in the age range in which hyperproduction of IFNgamma as recently been identified as a common feature of the atopic phenotype. The findings demonstrate the potency of IFNgamma promoter methylation as a mechanism for control of human IFNgamma gene expression, particularly during early life. Differential regulation of IFNgamma promoter methylation in T cells may be an important contributory factor in atopy development in childhood, and this possibility warrants further detailed investigation.

Self-management procedures have been used in school settings to successfully reduce problem behaviors, as well as to reinforce appropriate behavior. A multiple-baseline across participants design was applied in this study to evaluate the effects of using a self-management procedure to enhance the classroom preparation skills of secondary school students with attention-deficit/ hyperactivity disorder (ADHD). Three male students enrolled in a public secondary school were selected for this study because teacher reports suggested that these students were insufficiently prepared for class and inconsistently completed assignments. The intervention involved training in self-management procedures focusing on the improvement of classroom preparation skills. Following the intervention, the training process was systematically faded. Results were consistent across the 3 participants in enhancing classroom preparation behaviors. Implications for practice and future research are discussed.

Chaetosphaeria tortuosa is described as the newly discovered teleomorph of Menispora tortuosa, based on specimens from Canada and the Czech Republic, and single spore isolations from both morphs. The fungus produces superficial, more or less globose, papillate, dark brown to black smooth perithecia (200-)220-250 x (220-)230-260 microm. The asci are unitunicate, 8-spored, cylindrical-fusiform, (110-)120-133(-145) x 12-14 with a distinct apical, nonamyloid annulus 1-1.5 microm high, 3.5-4 microm wide. The ascospores are fusiform, 19-24 x 5-6 microm, hyaline, 3-septate, smooth, and 2-seriate in the ascus. The morphology of the teleomorph and anamorph are similar to that of C. ovoidea (anamorph: M. glauca), differing in dimensions of asci and ascospores, and in the disposition and morphology of the phialides of the anamorphs. The generic concept and phylogeny of Menispora is briefly discussed, and a key to the 11 species currently accepted in the genus is provided.

A number of laboratories have reported cord blood T cell responses to ubiquitous environmental Ags, including allergens, by proliferation and cytokine secretion. Moreover, the magnitude of these responses has been linked with risk for subsequent expression of allergy. These findings have been widely interpreted as evidence for transplacental priming and the development of fetal T memory cells against Ags present in the maternal environment. However, we present findings below that suggest that neonatal T cell responses to allergens (and other Ags) differ markedly from those occurring in later life. Notably, in contrast to allergen-responsive adult CD4(+) T cell cultures, responding neonatal T cell cultures display high levels of apoptosis. Comparable responses were observed against a range of microbial Ags and against a parasite Ag absent from the local environment, but not against autoantigen. A notable finding was the appearance in these cultures of CD4(+)CD25(+)CTLA4(+) T cells that de novo develop MLR-suppressive activity. These cells moreover expressed CD45RA and CD38, hallmarks of recent thymic emigrants. CFSE-labeling studies indicate that the CD4(+)CD25(+) cells observed at the end of the culture period were present in the day 0 starting populations, but they were not suppressive in MLR responses. Collectively, these findings suggest that a significant component of the reactivity of human neonatal CD4(+) T cells toward nominal Ag (allergen) represents a default response by recent thymic emigrants, providing an initial burst of short-lived cellular immunity in the absence of conventional T cell memory, which is limited in intensity and duration via the parallel activation of regulatory T cells.

Escherichia coli possesses a two-domain flavohemoglobin, Hmp, implicated in nitric oxide (NO) detoxification. To determine the contribution of each domain of Hmp toward NO detoxification, we genetically engineered the Hmp protein and separately expressed the heme (HD) and the flavin (FD) domains in a defined hmp mutant. Expression of each domain was confirmed by Western blot analysis. CO-difference spectra showed that the HD of Hmp can bind CO, but the CO adduct showed a slightly blue-shifted peak. Overexpression of the HD resulted in an improvement of growth to a similar extent to that observed with the Vitreoscilla hemeonly globin Vgb, whereas the FD alone did not improve growth. Viability of the hmp mutant in the presence of lethal concentrations of sodium nitroprusside was increased (to 30% survival after 2 h in 5 mM sodium nitroprusside) by overexpressing Vgb or the HD. However, maximal protection was provided only by holo-Hmp (75% survival under the same conditions). Cellular respiration of the hmp mutant was instantaneously inhibited in the presence of 13.5 microM NO but remained insensitive to NO inhibition when these cells overexpressed Hmp. When HD or FD was expressed separately, no significant protection was observed. By contrast, overexpression of Vgb provided partial protection from NO respiratory inhibition. Our results suggest that, despite the homology between the HD from Hmp and Vgb (45% identity), their roles seem to be quite distinct.

Background: Severe asthma is a frequent cause of hospital admission, especially among children. The main environmental triggers of airway inflammation in asthma are viruses and aeroallergens. These agents elicit reciprocal immune responses, characterised by production of T helper 1 and T helper 2 cytokines, respectively. There is no genetic explanation for how hyper-responsiveness to these disparate environmental stimuli develops among individuals with asthma. Our aim was to assess relation between an IL12B promoter polymorphism and asthma., Methods: We did a cohort study in which we initially genotyped 411 6-year olds for the IL12B promoter polymorphism. We then assessed the relation between this polymorphism and asthma severity. A further 85 asthmatic children in an additional sample of 433 children from the same cohort were then assessed to confirm these findings. We also examined in-vitro interleukin-12 responses in a subgroup of individuals., Findings: Heterozygosity for the IL12B promoter polymorphism was observed in 76% (16) of atopic and non-atopic individuals with severe asthma in the initial sample. By comparison, heterozygotes comprised only 31% (17) of the moderate asthma group, and 48% (20) of individuals with mild asthma were heterozygous, as were unaffected controls. These findings were confirmed in the second sample (overall p<0.0001). Our data suggest that IL12B promoter heterozygosity contributes to asthma severity rather than susceptibility per se. The severity-predisposing genotype was associated with reduced interleukin 12 p40 gene transcription and decreased interleukin 12 p70 secretion., Interpretation: Interleukin 12 plays a key part in antagonism of T helper 2 differentiation, and in induction of antiviral host defense. Genetically determined attenuation of interleukin-12 response capacity would, therefore, provide a plausible common immunological pathway to disease severity for the two major forms of asthma.

IFN-gamma is a potent pleiotropic Th1 cytokine, the production of which is tightly regulated during fetal development. Negative control of fetal/neonatal IFN-gamma production is generally attributed to the Th1-antagonistic effect of mediators produced by the placenta, but evidence exists of additional and more direct transcriptional regulation. We report that neonatal (cord blood) CD3(+)/CD45RO(-) T cells, in particular the CD4(+)/CD45RO(-) subset, are hypermethylated at CpG and non-CpG (CpA and CpT) sites within and adjacent to the IFN-gamma promoter. In contrast, CpG methylation patterns in cord blood IFN-gamma-producing CD8(+)/CD45RO(-) T cells and CD56(+)/CD16(+)/CD3(-) NK cells did not differ significantly from those in their adult counterparts. Consistent with this finding, IFN-gamma production by stimulated naive cord blood CD4(+) T cells is reduced 5- to 10-fold relative to adult CD4(+) T cells, whereas production levels in neonatal and adult CD8(+) T cells are of a similar order. Evidence of significant CpA and CpT methylation was not discovered in promoter sequence from other cytokines (IL-4, TNF-alpha, or IFN-gammaR alpha-chain). We additionally demonstrate that overexpression of DNA methyltransferase 3a in embryonic kidney carcinoma cells is accompanied by CpA methylation of the IFN-gamma promoter.

Sheep immunoglobulin (Ig) heavy-chain (V(H)DJ(H)) and lambda light-chain variable region (V(lambda)J(lambda)) nucleotide coding sequence was isolated by reverse transcriptase-polymerase chain reaction (RT-PCR) from abomasal lymph node (ALN) B cells of immune sheep challenged with the gastrointestinal nematode parasite Haemonchus contortus. Single-chain antibodies (scFv) were then constructed with the purified V(H)DJ(H) and V(lambda)J(lambda) Ig gene region DNA using oligonucleotides to PCR and join the variable regions to a central [Gly(4)Ser](3)-linker. In a similar fashion 5'-SfiI and 3'-NotI restriction endonuclease sites were added for cloning into a phagemid expression vector. Expression of sheep scFv from pHFA phagemid in an amber-suppresser strain of Escherichia coli, after infection with filamentous phage, resulted in 10(9) sheep scFv antibodies displayed as a library on phagemid particles. Western blot analysis demonstrated sheep scFv gene expression in E. coli cell lysate and on purified library phage. In addition, four rounds of scFv-library selection against H. contortus surface antigen resulted in a 300-fold increase in the elution titre of phage recovered from parasite surface antigen. Nearly 1000 of the selected and eluted scFvs were expressed in an attempt to identify monoclonal sheep scFv against parasite antigen. Only low affinity clones were isolated during screening of this sheep scFv-library, suggesting different strategies will be needed for isolation of specific high affinity recombinant antibody in future studies.

The potential of repetitive-sequence-based polymerase chain reaction (rep-PCR) fingerprinting of fungal genomic DNA as a rapid and simple alternative to random amplified polymorphic DNA (RAPD) analysis in the study of phylogenetic relationships, and also as a diagnostic method, was investigated with species of Tilletia. DNA primers (BOX, ERIC, and REP) corresponding to conserved repetitive element motifs, originally described in prokaryotes, were used to generate genomic fingerprints of T. indica, T. walkeri, T. controversa, T. laevis, T. tritici, T. goloskokovii, T. barclayana, and members of the T. fusca complex. Computer-assisted analysis of the database of combined fingerprints clearly distinguished each taxon and indicated phylo-genetic relationships consistent with previously reported RAPD analyses. There were three main clusters with isolates showing 35 to 40% similarity. Group 1 included T. indica and T. walkeri; group 2 included members of the T. fusca complex, as well as T. controversa, T. laevis, T. tritici, and T. goloskokovii; and group 3 included only T. barclayana. If, as is likely, the conserved repetitive element motifs on which this technique is based are widespread or universal in fungal species, rep-PCR shows strong potential, not only as a simple generic taxonomic tool, but also as a diagnostic method.

High school principals' acceptability ratings of three school-based programs for the prevention of adolescent suicide were examined. From a random sample of members from the 1994-1995 membership directory of the National Association of Secondary School Principals (NASSP), a total of 185 (40%) respondents completed the Suicide Prevention Program Rating Profile (SPPRP), a measure designed to evaluate the acceptability of suicide prevention programs, after reading a description of a particular prevention program. Programs evaluated for their acceptability included (1) curriculum-based programs presented to students, (2) in-service presentations to school staff, and (3) student self-report screening measures. The results indicated that the curriculum-based and staff in-service programs were significantly more acceptable to principals than was the schoolwide student screening program. No significant differences between the acceptability of curriculum-based and inservice programs were found. Limitations of the study and implications for practice and research are discussed.

Six extracts were prepared from Alternaria tenuis isolated ATCC 6663, ATCC 16086 and DAOM (Agriculture Canada) 183905 grown separately on two synthetic media, revised tobacco and Czapek's, and their biochemical and immunological properties were examined. High-performance liquid chromatography revealed considerable variations in UV absorbance and carbohydrate profiles among extracts from the different isolates. These differences were less marked among samples of the same isolate cultured on different media. Enzyme screening showed that all extracts contained large amounts of phosphatases and glucosidases and moderate quantities of esterases. Only the alpha-galactosidase activity showed any correlation with allergenic activity. No significant variation was observed in isoelectric focusing patterns. Extensive antigenic cross-reactivity even between the different isolates was found in precipitin studies. In mouse IgE passive cutaneous anaphylaxis tests, all extracts gave reactions of similar intensity. In direct RAST and RAST inhibition assays, ATCC 16086 grown on revised tobacco medium was found to be the most potent and approached the activity of an extract from a commercial material (B-I). DAOM 183905 grown on either medium was next in potency while ATCC 6663 samples were the least potent. The results indicate that it is possible to obtain extracts of high allergenic potency for standardization purposes from growth of selected A. tenuis isolates on a chemically defined medium.

1. The effect of iron chelators on iron uptake, ferritin and total protein synthesis was studied in cultured Chang cells. Desferrioxamine depressed ferritin synthesis and completely inhibited iron uptake by ferritin protein. Rhodotorulic acid reduced iron uptake by the cells but had little effect on ferritin synthesis. Diethylenetriamine pentaacetic acid produced complete inhibition of iron uptake and all protein synthesis. 2,3-Dihydroxybenzoic acid (2,3-DHB) had no effect in this system. 2. When 2,3-DHB was incubated with a liver homogenate, its subsequent addition to a Chang cell culture resulted in depression of ferritin synthesis, iron uptake into the protein and some depression of total protein synthesis. Pretreatment of rhodotorulic acid did not affect its properties. 3. Non-ferritin iron in the Chang cell cytosol was dialysable, available for binding to transferrin and formed chelates which appeared, on gel chromatography, to be of low molecular weight. Gel chromatography of cytosol after incubation of the cells with chelating agents showed non-ferritin iron to be in a similar form. 4. Loss of non-ferritin iron from the cells occurred only when the transferrin in the medium was unsaturated. In the presence of chelating agents non-ferritin iron was lost from the cells even when transferrin was 100% saturated. 5. The results confirm the presence of an intracellular labile iron pool which is available for chelation, and demonstration that different iron chelators have different metabolic effects.

Iron uptake by Chang liver cells in culture is about thirty times as great when ferric nitriloacetate is used as a donor as when iron-transferrin is used. Iron uptake from ferric citrate is no greater than from iron-transferrin. Most of the intracellular iron derived from transferrin is found in the supernatant after 20 000 x g centrifugation of the cell homogenate for 40 min: about half of this is in the form of ferritin. Iron derived from ferric nitriloacetate is found largely in the membranous pellet after centrifugation and very little of this is in the form of ferritin. Iron incorporated in cytosol ferritin is easily available for chelation by desferrioxamine and this process is facilitated by ascorbic acid. Membrane-bound iron is less available for chelation. This tissue culture model forms a convenient basis for the study of iron overlead and iron chelation.

A number of iron chelating agents, consisting largely of hydroxamic acid and benzoic acid derivatives, have been studied in an in vitro Chang cell culture system to determine their effect on cellular iron uptake, ferritin synthesis and the incorporation of iron into ferritin. The results have been compared with those of a previous study in which iron balance was determined in hypertransfused rats. Both techniques appear to be of value in screening new iron chelating agents for potential therapeutic use in patients with iron overload.

For the past several years, we have searched for an orally effective iron-chelating drug and report here on several compounds which warrant further investigations based on their ability to promote iron excretion in the hypertransfused rat. Administrered orally, 2,3-dihydroxybenzyolglycine induced both urinary and fecal iron excretion, suggesting that a conjugate of 2,3-dihydroxybenzoic acid may be more efficacious than the parent compound. Tropolone, although rather toxic, stimulated fecal excretion of iron when given p.o. at low doses. Evaluation of less toxic derivatives of tropolone appears to be justifiable. L-Histidine may also be of use in chelatin therapy. Fecal iron excretion is significantly increased in response to oral doses of this essential amino acid. Lastly, cholylhydroxamic acid proved to be the most efficacious oral agent examined thus far. A marked increase in fecal iron excretion results from its administration.

Chang cells have been used as a stable model system for the study of cellular iron metabolism. Iron uptake and the stimulation of ferritin synthesis have been studied together with iron incorporation into the ferritin molecule. About 25-30% of the iron taken up by the cells is found in a soluble, non-haem, non-ferritin form which can be chelated by a number of compounds. Ferritin synthesis is inhibited by the presence of desferrioxamine but not by zinc ions.