bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epidermal Growth Factor Receptor Expression and Activation in Neuroendocrine Tumours
Authors: Shah T. , Hochhauser D. , Frow R. , Quaglia A. , Dhillon A. P. , Caplin M. E. 
Published: March 2006

AbstractEpidermal growth factor receptor (EGFR) is expressed in many cancers and is associated with poor prognosis. EGFR activation pathways have been well characterised using tumour cell lines and are known to involve EGFR activation through autophosphorylation. Phosphorylation of downstream signalling molecules, such as ERK1/2 (extra‐cellular regulated kinase 1 and 2) and PKB/Akt (protein kinase B), leads to enhanced tumour cell survival and proliferation. Although EGFR expression has been determined in neuroendocrine tumour tissue, its activation and subsequent effects on the downstream signalling molecules, ERK1/2 and Akt, have not been studied. We therefore planned to determine the role of EGFR in neuroendocrine tumours (NETs) by determining its pattern of expression and activation, and the subsequent activation of downstream signalling molecules ERK1/2 and Akt. Paraffin‐embedded tumour tissue was available from 98 patients with NETs (39 foregut, 42 midgut, four hindgut, five paragangliomas, and four of unknown origin). Immunohistochemical evaluation was performed for the expression of EGFR, p‐EGFR, p‐Akt, and p‐ERK1/2. Ninety‐six percent of tumour samples were positive for EGFR expression; 63% were positive for activated EGFR; 76% were positive for activated Akt; and 96% were positive for activated ERK1/2. Importantly, the histological score for the activation of Akt and ERK1/2 correlated with the histological score for activated EGFR. These data provide a rationale for considering EGFR inhibitors in the treatment of NETs. Additionally, direct inhibition of Akt and ERK1/2 may provide further therapeutic options in the treatment of NETs in the future.
Information Processing in the Hypothalamus: Peptides and Analogue Computation
Authors: Leng G. , Ludwig M. 
Published: March 2006

Abstract
‘Lovers and madmen have such seething brains,/Such shaping fantasies, that apprehend/More than cool reason ever comprehends’(A Midsummer Night's Dream, Act V Scene I)
Peptides in the hypothalamus are not like conventional neurotransmitters; their release is not particularly associated with synapses, and their long half‐lives mean that they can diffuse to distant targets. Peptides can act on their cells of origin to facilitate the development of patterned electrical activity, they can act on their neighbours to bind the collective activity of a neural population into a coherent signalling entity, and the co‐ordinated population output can transmit waves of peptide secretion that act as a patterned hormonal analogue signal within the brain. At their distant targets, peptides can re‐programme neural networks, by effects on gene expression, synaptogenesis, and by functionally rewiring connections by priming activity‐dependent release.
FAST‐TRACK: A southern California freeway is a physical and social barrier to gene flow in carnivores
Authors: RILEY SETH P. D. , POLLINGER JOHN P. , SAUVAJOT RAYMOND M. , YORK ERIC C. , BROMLEY CASSITY , FULLER TODD K. , WAYNE ROBERT K. 
Published: March 2006

AbstractRoads present formidable barriers to dispersal. We examine movements of two highly mobile carnivores across the Ventura Freeway near Los Angeles, one of the busiest highways in the United States. The two species, bobcats and coyotes, can disappear from habitats isolated and fragmented by roads, and their ability to disperse across the Ventura Freeway tests the limits of vertebrates to overcome anthropogenic obstacles. We combine radio‐telemetry data and genetically based assignments to identify individuals that have crossed the freeway. Although the freeway is a significant barrier to dispersal, we find that carnivores can cross the freeway and that 5–32% of sampled carnivores crossed over a 7‐year period. However, despite moderate levels of migration, populations on either side of the freeway are genetically differentiated, and coalescent modelling shows their genetic isolation is consistent with a migration fraction less than 0.5% per generation. These results imply that individuals that cross the freeway rarely reproduce. Highways and development impose artificial home range boundaries on territorial and reproductive individuals and hence decrease genetically effective migration. Further, territory pile‐up at freeway boundaries may decrease reproductive opportunities for dispersing individuals that do manage to cross. Consequently, freeways are filters favouring dispersing individuals that add to the migration rate but little to gene flow. Our results demonstrate that freeways can restrict gene flow even in wide‐ranging species and suggest that for territorial animals, migration levels across anthropogenic barriers need to be an order of magnitude larger than commonly assumed to counteract genetic differentiation.
Extracytoplasmic prosthetic group ligation to apoproteins: maturation of c‐type cytochromes
Authors: Turkarslan Serdar , Sanders Carsten , Daldal Fevzi 
Published: March 2006

SummaryIn all organisms, haem is post‐translationally and covalently attached to c apocytochromes to produce c holocytochromes via a process called c‐type cytochromes maturation, which involves numerous components. In bacteria it was not clear which of these components catalyses the extracytoplasmic haem–apocytochrome ligation per se. In this issue of Molecular Microbiology, Feissner and colleagues report that a single polypeptide from Helicobacter pylori, corresponding to the fusion of two proteins found in other organisms, performs haem ligation to a coexpressed Bordetella pertussis apocytochrome c in an Escherichia coli mutant lacking its own cytochrome c maturation proteins. This simple experimental system pinpoints the components catalysing extracytoplasmic covalent haem ligation and raises intriguing issues about the requirements for delivery of haem and apocytochrome c substrates to produce c holocytochromes.
Interactions between C ring proteins and export apparatus components: a possible mechanism for facilitating type III protein export
Authors: González‐Pedrajo Bertha , Minamino Tohru , Kihara May , Namba Keiichi 
Published: March 2006

SummaryThe flagellar switch proteins of Salmonella, FliG, FliM and FliN, participate in the switching of motor rotation, torque generation and flagellar assembly/export. FliN has been implicated in the flagellar export process. To address this possibility, we constructed 10‐amino‐acid scanning deletions and larger truncations over the C‐terminal domain of FliN. Except for the last deletion variant, all other variants were unable to complement a fliN null strain or to restore the export of flagellar proteins. Most of the deletions showed strong negative dominance effects on wild‐type cells. FliN was found to associate with FliH, a flagellar export component that regulates the ATPase activity of FliI. The binding of FliM to FliN does not interfere with this FliN–FliH interaction. Furthermore, a five‐protein complex consisting of FliG, His‐tagged FliM, FliN, FliH and FliI was purified by nickel‐affinity chromatography. FliJ, a putative general chaperone, is bound to FliM even in the absence of FliH. The importance of the C ring as a possible docking site for export substrates, chaperones and FliI through FliH for their efficient delivery to membrane components of the export apparatus is discussed.
Evolution of mutation rates in bacteria
Authors: Denamur Erick , Matic Ivan 
Published: March 2006

SummaryEvolutionary success of bacteria relies on the constant fine‐tuning of their mutation rates, which optimizes their adaptability to constantly changing environmental conditions. When adaptation is limited by the mutation supply rate, under some conditions, natural selection favours increased mutation rates by acting on allelic variation of the genetic systems that control fidelity of DNA replication and repair. Mutator alleles are carried to high frequency through hitchhiking with the adaptive mutations they generate. However, when fitness gain no longer counterbalances the fitness loss due to continuous generation of deleterious mutations, natural selection favours reduction of mutation rates. Selection and counter‐selection of high mutation rates depends on many factors: the number of mutations required for adaptation, the strength of mutator alleles, bacterial population size, competition with other strains, migration, and spatial and temporal environmental heterogeneity. Such modulations of mutation rates may also play a role in the evolution of antibiotic resistance.
A re‐examination of the minor role of unstirred layers during the measurement of transport coefficients of Chara corallina internodes with the cell pressure probe
Authors: YE QING , KIM YANGMIN , STEUDLE ERNST 
Published: March 2006

ABSTRACTThe impact of unstirred layers (USLs) during cell pressure probe experiments with Chara corallina internodes has been quantified. The results show that the hydraulic conductivity (Lp) measured in hydrostatic relaxations was not significantly affected by USLs even in the presence of high water flow intensities (‘sweep‐away effect’). During pressure clamp, there was a reversible reduction in Lp by 20%, which was explained by the constriction of water to aquaporins (AQPs) in the C. corallina membrane and a rapid diffusional equilibration of solutes in arrays where water protruded across AQPs. In osmotic experiments, Lp, and permeability (Ps) and reflection (σs) coefficients increased as external flow rate of medium increased, indicating some effects of external USLs. However, the effect was levelling off at ‘usual’ flow rates of 0.20–0.30 m s−1 and in the presence of vigorous stirring by air bubbles, suggesting a maximum thickness of external USLs of around 30 µm including the cell wall. Because the diameters of internodes were around 1 mm, internal USLs could have played a significant or even a dominating role, at least in the presence of the rapidly permeating solutes used [acetone, 2‐propanol and dimethylformamide (DMF)]. A comparison of calculated (diffusion kinetics) and of measured permeabilities indicated an upper limit of the contribution of USLs for the rapidly moving solute acetone of 29%, and of 15% for the less rapidly permeating DMF. The results throw some doubt on recent claims that in C. corallina, USLs rather than the cell membrane dominate solute uptake, at least for the most rapidly moving solute acetone.
Analysis of deaths with an unknown cause in epidemiologic analyses of mortality burden
Authors: Rowe Alexander K. 
Published: March 2006

SummaryObjective  To describe options for analysing deaths with an unknown cause, which often occur in community‐based studies that are used to estimate disease‐specific mortality burden and trends in low‐income countries.Methods  Mathematical formulae were derived that accommodate deaths with an unknown cause for the disease‐specific mortality rate, proportion of deaths attributable to the disease and all‐cause mortality rate. Seven specific options are presented, including example calculations from a study of childhood malaria mortality in The Gambia. An algorithm is proposed to help make decisions on analysing deaths with an unknown cause.Results  In the Gambian study, 25.2% of deaths had an unknown cause. Three options would result in 23.6% (minimum), 48.8% (maximum) and 28.7% (probably the best estimate) of deaths attributed to malaria. The best analysis option depends on the disease of interest: diseases for which the diagnostic method has high sensitivity and specificity (e.g., measles, neonatal tetanus) are best analysed assuming that deaths with an unknown cause never have this cause, while diseases for which specificity and/or sensitivity is low (e.g., malaria) are likely to account for some proportion of deaths with an unknown cause.Conclusions  The most important aspects of analysing deaths with unknown cause are choosing appropriate assumptions, describing them explicitly and performing a sensitivity analysis. Studies of causes of death should report several key pieces of information on deaths with unknown cause to aid interpretation.
Comparison of family reporting of pregnancy status with a post‐mortemβ‐HCG test in deceased women: a study in Pointe‐Noire, Congo
Authors: Le Coeur Sophie , Ronsmans Carine , Halembokaka Gaston , Augereau‐Vacher Christine , Khlat Myriam 
Published: March 2006

SummaryObjective  To compare family reports of pregnancy status in deceased women with a biological assessment of pregnancy using a post‐mortem β‐HCG test.Method  We investigated the deaths of females of reproductive age registered at the Pointe Noire morgue from June 30 to October 18, 2001. A physician interviewed relatives about the circumstances of death, in particular whether the woman had been pregnant at the time of death, and whether she had delivered or had an abortion (induced or spontaneous) within the past 6 weeks. The bodies were then examined and blood samples taken for β‐HCG testing.Results  Among 368 deaths of women of reproductive age registered, 34 deaths were identified as pregnancy‐related: 23 by both the family interview and the β‐HCG test, five by β‐HCG test only and six were β‐HCG negative but the family had reported a recent delivery.Conclusion  In this setting, the approach based on family reports underestimates mortality during pregnancy by 24% and mortality during pregnancy or within 6 weeks postpartum by 15%.
Malaria prevention in The Gambia: patterns of expenditure and determinants of demand at the household level
Authors: Wiseman V. , McElroy B. , Conteh L. , Stevens W. 
Published: March 2006

SummaryObjective  To provide a better understanding of (1) the amounts households in The Gambia spend on a wide variety of malaria prevention measures, (2) how expenditure fluctuates throughout the year and (3) the main determinants of expenditure.Methods  A random sample of 1700 households from the Farafenni region were interviewed about their expenditure on malaria prevention over the past 2 weeks. Interviews were staggered over 12 months. Expenditure was measured for bed nets, treating and repairing bed nets, aerosols, coils, indoor spraying, smoke and other prevention strategies such as drinking herbs and cleaning the outside environment.Results  Expenditure on bed nets, including treatment and repair, constituted only 10% of total expenditure on malaria prevention. Every fortnight, households spent an average of 8.40 Dalasis (D) on coils, 4.20 D on indoor sprays, 3.09 D on smoke and 3.06 D on aerosols, together making up 81% of total fortnightly expenditure. Of the 442 households that did not own a bed net, 68% said it was because they could not afford one. Every 2 months, the same households spent an average of US$5, the equivalent to the cost of an insecticide treated bed net, on other forms of prevention. Total expenditure was 42% higher during the wet season than for the rest of the year. For every month of the year, coils were the dominant form of prevention expenditure. Wealth, age, occupation of household head, location of residence and month of the year were significant determinants of prevention expenditure.Conclusions  Households in The Gambia spend considerable amounts on a range of malaria prevention products and activities throughout the year. Bed nets represent a relatively small proportion of this expenditure even though they are perceived to be the most efficient and effective method of malaria control. A more concerted effort is needed to develop appropriate targeting strategies to encourage bed net use especially for children <5 years of age. Equal emphasis should be given to addressing barriers to purchasing nets such as their relative high upfront cost.
The treatment of psoriasis vulgaris: 1% topical methotrexate gel
Authors: Eskicirak Buket , Zemheri Ebru , Cerkezoglu Arzu 
Published: March 2006

AbstractBackground  In general, 70% of patients with psoriasis prefer topical therapy as the treatment of choice.Aim  To evaluate the efficacy and tolerability of 1% topical methotrexate gel vs. placebo (vaseline ointment) as treatment for psoriasis.Methods  Forty patients (20 females and 20 males) with chronic plaque‐type psoriasis joined the study. Each patient was allocated to apply 1% methotrexate gel and placebo topically to their two target lesions, equal in area and disease severity, twice daily for 8 weeks. Lesions were scored at baseline and after 2, 4, 6, and 8 weeks of treatment for erythema, scale, and infiltration. The global improvement and histopathologic features were also assessed after methotrexate treatment.Results  At the end of treatment, erythema was cleared totally in 47.5% of patients treated with methotrexate vs. 7.5% of those treated with placebo, and infiltration in 22% of patients treated with methotrexate vs. 2.5% of those treated with placebo (P < 0.01). Clinical improvement was almost the same for the two groups with regard to scale (P < 0.5). The global improvement was 97% for patients treated with methotrexate vs. 60% for those treated with placebo, and a significant difference was found between the groups (P < 0.01). Histopathologic improvement was achieved in the methotrexate group (P < 0.01). No side‐effects were observed.Conclusion  The findings of this study suggest that methotrexate 1% in a hydrophilic gel is well tolerated and significantly more effective than placebo as a topical medication for the treatment of psoriasis vulgaris.
Consumption of fish, butter and margarine during pregnancy and development of allergic sensitizations in the offspring: role of maternal atopy
Authors: Calvani Mauro , Alessandri Claudia , Sopo Stefano Miceli , Panetta Valentina , Pingitore Giuseppe , Tripodi Salvatore , Zappalà Daniela , Zicari Anna Maria ,   the Lazio Association of Pediatric Allergology (APAL) Study Group
Published: March 2006

It has been suggested that changes in dietary habits, particularly increased consumption of ω‐6 polyunsaturated fatty acids (PUFA) and decreased consumption of ω‐3 PUFAs may explain the increase in atopic disease seen in recent years. Furthermore, it seems possible that it is mainly prenatal or very early life environmental factors that influence the development of allergic diseases. It has also been suggested that intrauterine risk factors may act differently if mother themselves suffer from allergic disease.The aim of this study was to investigate whether the consumption of fish, butter and margarine during pregnancy might influence the development of allergic sensitizations in the offspring. The study population was divided into the offspring of allergic and non‐allergic mothers.This was a retrospective cohort study enrolling 295 offspring of allergic mothers and 693 of non‐allergic mothers. Information regarding maternal intake of fish, butter and margarine during pregnancy as well as other prenatal and perinatal confounding factors were retrospectively assessed by parental report via a standardized questionnaire. Atopy was determined by skin‐prick tests (SPT) to eight prevalent inhalant allergens and two foods.In the allergic mothers’ group there is no clear correlation between maternal intakes of fish, butter and margarine and sensitizations to food or inhalants.In the non‐allergic mothers’ group there was no correlation between butter and margarine intake and food or inhalant sensitizations. On the contrary, a protective effect of fish intake on SPT positivity was observed. In particular, frequent maternal intake (‘2–3 times/wk or more’) of fish reduced the risk of food sensitizations by over a third (aOR 0.23; 95% CI: 0.08–0.69). A similar trend, even if not significant, was found for inhalants. Finally, even in the whole study population, i.e. allergic group plus non‐allergic group, there was a similar trend between increased consumption of fish and decreased prevalence of SPT positivity for foods.This study shows that frequent intake of fish during pregnancy may contrast the development of SPT sensitizations for foods in the offspring of mothers without atopic disease. Therefore, larger prospective studies are needed, enrolling mothers with and without allergic disease, to confirm these results.
Faecal SIgA secretion in infants fed on pre‐ or probiotic infant formula
Authors: Bakker‐Zierikzee A. M. , van Tol E. A. F. , Kroes H. , Alles M. S. , Kok F. J. , Bindels J. G. 
Published: March 2006

Secretory immunoglobulin A (SIgA) plays an important role in the defence of the gastrointestinal tract. The level of faecal SIgA antibody is associated with increased neutralization and clearance of viruses. Formula‐fed infants who lack the transfer of protective maternal SIgA from breast milk may benefit from strategies to support maturation of humoral immunity and endogenous production of SIgA. We aimed at studying the effects of standard, prebiotic and probiotic infant formulas on the faecal SIgA levels. At birth, infants of whom the mother had decided not to breastfeed were allocated to one of three formula groups in a randomized, double‐blind fashion. Nineteen infants received standard infant formula; 19 received prebiotic formula containing a specific mixture of 0.6 g galacto‐oligosaccharides (GOS)/fructo‐oligosaccharides (FOS)/100 ml formula and 19 received probiotic formula containing 6.0 × 109 cfu Bifidobacterium animalis/100 ml formula. Faecal samples were taken on postnatal day 5, day 10, wk 4 and every 4 wk thereafter until wk 32. SIgA in faeces was determined by an enzyme‐linked immunosorbent assay. During the intervention, infants fed on prebiotic formula showed a trend towards higher faecal SIgA levels compared with the standard formula‐fed infants reaching statistical significance at the age of 16 wk. In contrast, infants fed on the probiotic formula showed a highly variable faecal SIgA concentration with no statistically significant differences compared with the standard formula group. Formula‐fed infants may benefit from infant formulas containing a prebiotic mixture of GOS and FOS because of the observed clear tendency to increase faecal SIgA secretion. Adding viable B. animalis strain Bb‐12 to infant formula did not reveal any sign for such a trend.
Size and scaling of predator–prey dynamics
Authors: Weitz Joshua S. , Levin Simon A. 
Published: March 2006

AbstractWe propose a scaled version of the Rosenzweig–MacArthur model using both Type I and Type II functional responses that incorporates the size dependence of interaction rates. Our aim is to link the energetic needs of organisms with the dynamics of interacting populations, for which survival is a result of a game‐theoretic struggle for existence. We solve the scaled model of predator–prey dynamics and predict population level characteristics such as the scaling of coexistence size ranges and the optimal predator–prey size ratio. For a broad class of such models, the optimal predator–prey size ratio given available prey of a fixed size is constant. We also demonstrate how scaling predictions of prey density differ under resource limitation vs. predator drawdown. Finally, we show how evolution of predator size can destabilize population dynamics, compare scaling of predator–prey cycles to previous work, as well as discuss possible extensions of the model to multispecies communities.