Showing papers by "Trinity College, Dublin published in 1997"
TL;DR: Bacillus subtilis is the best-characterized member of the Gram-positive bacteria, indicating that bacteriophage infection has played an important evolutionary role in horizontal gene transfer, in particular in the propagation of bacterial pathogenesis.
Abstract: Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large proportion of the genetic capacity is devoted to the utilization of a variety of carbon sources, including many plant-derived molecules. The identification of five signal peptidase genes, as well as several genes for components of the secretion apparatus, is important given the capacity of Bacillus strains to secrete large amounts of industrially important enzymes. Many of the genes are involved in the synthesis of secondary metabolites, including antibiotics, that are more typically associated with Streptomyces species. The genome contains at least ten prophages or remnants of prophages, indicating that bacteriophage infection has played an important evolutionary role in horizontal gene transfer, in particular in the propagation of bacterial pathogenesis.
3,753 citations
TL;DR: An increased plasma total homocysteine level confers an independent risk of vascular disease similar to that of smoking or hyperlipidemia, and compared with nonusers of vitamin supplements, the small number of subjects taking such vitamins appeared to have a substantially lower risk ofascular disease, a proportion of which was attributable to lower plasma homocy steine levels.
Abstract: Context. —Elevated plasma homocysteine is a known risk factor for atherosclerotic vascular disease, but the strength of the relationship and the interaction of plasma homocysteine with other risk factors are unclear. Objective. —To establish the magnitude of the vascular disease risk associated with an increased plasma homocysteine level and to examine interaction effects between elevated plasma homocysteine level and conventional risk factors. Design. —Case-control study. Setting. —Nineteen centers in 9 European countries. Patients. —A total of 750 cases of atherosclerotic vascular disease (cardiac, cerebral, and peripheral) and 800 controls of both sexes younger than 60 years. Measurements. —Plasma total homocysteine was measured while subjects were fasting and after a standardized methionine-loading test, which involves the administration of 100 mg of methionine per kilogram and stresses the metabolic pathway responsible for the irreversible degradation of homocysteine. Plasma cobalamin, pyridoxal 5'-phosphate, red blood cell folate, serum cholesterol, smoking, and blood pressure were also measured. Results. —The relative risk for vascular disease in the top fifth compared with the bottom four fifths of the control fasting total homocysteine distribution was 2.2 (95% confidence interval, 1.6-2.9). Methionine loading identified an additional 27% of atrisk cases. A dose-response effect was noted between total homocysteine level and risk. The risk was similar to and independent of that of other risk factors, but interaction effects were noted between homocysteine and these risk factors; for both sexes combined, an increased fasting homocysteine level showed a more than multiplicative effect on risk in smokers and in hypertensive subjects. Red blood cell folate, cobalamin, and pyridoxal phosphate, all of which modulate homocysteine metabolism, were inversely related to total homocysteine levels. Compared with nonusers of vitamin supplements, the small number of subjects taking such vitamins appeared to have a substantially lower risk of vascular disease, a proportion of which was attributable to lower plasma homocysteine levels. Conclusions. —An increased plasma total homocysteine level confers an independent risk of vascular disease similar to that of smoking or hyperlipidemia. It powerfully increases the risk associated with smoking and hypertension. It is time to undertake randomized controlled trials of the effect of vitamins that reduce plasma homocysteine levels on vascular disease risk.
1,828 citations
TL;DR: A model is proposed in which this species is a degenerate tetraploid resulting from a whole-genome duplication that occurred after the divergence of Saccharomyces from Kluyveromyces, and protein pairs derived from this duplication event make up 13% of all yeast proteins.
Abstract: Gene duplication is an important source of evolutionary novelty Most duplications are of just a single gene, but Ohno proposed that whole-genome duplication (polyploidy) is an important evolutionary mechanism Many duplicate genes have been found in Saccharomyces cerevisiae, and these often seem to be phenotypically redundant Here we show that the arrangement of duplicated genes in the S cerevisiae genome is consistent with Ohno's hypothesis We propose a model in which this species is a degenerate tetraploid resulting from a whole-genome duplication that occurred after the divergence of Saccharomyces from Kluyveromyces Only a small fraction of the genes were subsequently retained in duplicate (most were deleted), and gene order was rearranged by many reciprocal translocations between chromosomes Protein pairs derived from this duplication event make up 13% of all yeast proteins, and include pairs of transcription factors, protein kinases, myosins, cyclins and pheromones Tetraploidy may have facilitated the evolution of anaerobic fermentation in Saccharomyces
1,760 citations
TL;DR: This review represents an update of the nomenclature system for the UDP glucuronosyltransferase gene superfamily, which is based on divergent evolution and is anticipated that this UGT gene nomenClature system will require updating on a regular basis.
Abstract: This review represents an update of the nomenclature system for the UDP glucuronosyltransferase gene superfamily, which is based on divergent evolution. Since the previous review in 1991, sequences of many related UDP glycosyltransferases from lower organisms have appeared in the database, which expand our database considerably. At latest count, in animals, yeast, plants and bacteria there are 110 distinct cDNAs/genes whose protein products all contain a characteristic 'signature sequence' and, thus, are regarded as members of the same superfamily. Comparison of a relatedness tree of proteins leads to the definition of 33 families. It should be emphasized that at least six cloned UDP-GlcNAc N-acetylglucosaminyltransferases are not sufficiently homologous to be included as members of this superfamily and may represent an example of convergent evolution. For naming each gene, it is recommended that the root symbol UGT for human (Ugt for mouse and Drosophila), denoting 'UDP glycosyltransferase,' be followed by an Arabic number representing the family, a letter designating the subfamily, and an Arabic numeral denoting the individual gene within the family or subfamily, e.g. 'human UGT2B4' and 'mouse Ugt2b5'. We recommend the name 'UDP glycosyltransferase' because many of the proteins do not preferentially use UDP glucuronic acid, or their nucleotide sugar preference is unknown. Whereas the gene is italicized, the corresponding cDNA, transcript, protein and enzyme activity should be written with upper-case letters and without italics, e.g. 'human or mouse UGT1A1.' The UGT1 gene (spanning > 500 kb) contains at least 12 promoters/first exons, which can be spliced and joined with common exons 2 through 5, leading to different N-terminal halves but identical C-terminal halves of the gene products; in this scheme each first exon is regarded as a distinct gene (e.g. UGT1A1, UGT1A2, ... UGT1A12). When an orthologous gene between species cannot be identified with certainty, as occurs in the UGT2B subfamily, sequential naming of the genes is being carried out chronologically as they become characterized. We suggest that the Human Gene Nomenclature Guidelines (http://www.gene.acl.ac.uk/nomenclature/guidelines.html++ +) be used for all species other than the mouse and Drosophila. Thirty published human UGT1A1 mutant alleles responsible for clinical hyperbilirubinemias are listed herein, and given numbers following an asterisk (e.g. UGT1A1*30) consistent with the Human Gene Nomenclature Guidelines. It is anticipated that this UGT gene nomenclature system will require updating on a regular basis.
1,075 citations
TL;DR: NF-kB can be considered as one of the most important transcription factors characterized in brain to date and it might be as crucial for neuronal and glial cell function as it is for immune cells.
983 citations
TL;DR: The introgression of zebu-specific alleles in African cattle afforded a high resolution perspective on the hybrid nature of African cattle populations and also suggested that certain West African populations of valuable disease-tolerant taurine cattle are under threat of genetic absorption by migrating zebe herds.
Abstract: Genetic variation at 20 microsatellite loci was surveyed to determine the evolutionary relationships and molecular biogeography of 20 different cattle populations from Africa, Europe and Asia. Phylogenetic reconstruction and multivariate analysis highlighted a marked distinction between humpless (taurine) and humped (zebu) cattle, providing strong support for a separate origin for domesticated zebu cattle. A molecular clock calculation using bison (Bison sp.) as an outgroup gave an estimated divergence time between the two subspecies of 610,000-850,000 years. Substantial differences in the distribution of alleles at 10 of these loci were observed between zebu and taurine cattle. These markers subsequently proved very useful for investigations of gene flow and admixture in African populations. When these data were considered in conjunction with previous mitochondrial and Y chromosomal studies, a distinctive male-mediated pattern of zebu genetic introgression was revealed. The introgression of zebu-specific alleles in African cattle afforded a high resolution perspective on the hybrid nature of African cattle populations and also suggested that certain West African populations of valuable disease-tolerant taurine cattle are under threat of genetic absorption by migrating zebu herds.
540 citations
TL;DR: These animals should provide a useful genetic background on which to express other mutant opsin transgenes, as well as a model to assess the therapeutic potential of re-introducing functional rhodopsin genes into degenerating retinal tissues.
Abstract: Retinitis pigmentosa (RP) represents the most common mendelian degenerative retinopathy of man, involving death of rod photoreceptors, cone cell degeneration, retinal vessel attenuation and pigmentary deposits1,2. The patient experiences night blindness, usually followed by progressive loss of visual field. Genetic linkage between an autosomal dominant RP locus and rhodopsin3, the photoreactive pigment of the rod cells, led to the identification of mutations within the rhodopsin gene in both dominant and recessive forms of RP3–7. To better understand the functional and structural role of rhodopsin in the normal retina and in the pathogenesis of retinal disease, we generated mice carrying a targeted disruption of the rhodopsin gene. Rho−/− mice do not elaborate rod outer segments, losing their photoreceptors over 3 months. There is no rod ERG response in 8-week-old animals. Rho+/− animals retain the majority of their photoreceptors although the inner and outer segments of these cells display some structural disorganization, the outer segments becoming shorter in older mice. These animals should provide a useful genetic background on which to express other mutant opsin transgenes, as well as a model to assess the therapeutic potential of re-introducing functional rhodopsin genes into degenerating retinal tissues.
529 citations
TL;DR: The variation of biophysical stimuli within the tissue can be plotted as 'mechano-regulatory pathway', which identifies the transition from motion-control to force-control as a branching event in the tissue differentiation sequence.
527 citations
TL;DR: A 3′ variable number of tandem repeat (VNTR) polymorphism at the dopamine transporter gene (DAT1) in a sample of 49 ADHD patients and their parents is examined using the haplotype relative risk (HRR) method, finding that the 480-bp allele was preferentially transmitted to ADHD probands.
Abstract: Attention deficit hyperactivity disorder (ADHD) is a common condition of childhood the symptoms of which include inattention, excessive motor activity, inpulsivity and distractibility. It is strongly familial and twin and adoption studies suggest that the familiality is due, at least in part, to shared genes. Gillis et al found concordance rates in ADHD for MZ and DZ twins of 81% and 29% respectively. Stimulant drugs (eg, methylphenidate) are effective in the treatment of ADHD and inhibit the dopamine transporter. This has led to the development of a hypodopaminergic hypothesis for the disease. Cook et al examined a 3' variable number of tandem repeat (VNTR) polymorphism at the dopamine transporter gene (DAT1) in a sample of 49 ADHD patients and their parents, using the haplotype relative risk (HRR) method. They found a significant association (chi 2 = 7.29, 1 d.f., P = 0.007) between ADHD and the 480-bp DAT1 VNTR allele. The authors stressed the importance of independent replication and we have achieved this in a study of 40 probands and their parents, using the same robust HRR method. As in the study of Cook et al we found that the 480-bp allele was preferentially transmitted to ADHD probands (chi 2 = 6.07, 1 d.f., P = 0.014).
506 citations
TL;DR: It is reported that the induction of stable homosynaptic LTD in the CA1 area of the hippocampus of awake adult rats is facilitated, rather than inhibited, by exposure to mild naturalistic stress.
Abstract: The induction of activity-dependent persistent increases in synaptic efficacy, such as long-term potentiation (LTP), is inhibited by behavioural stress. The question arises whether stress also affects the ability to induce persistent decreases in synaptic efficacy, such as long-term depression (LTD). We now report that the induction of stable homosynaptic LTD in the CA1 area of the hippocampus of awake adult rats is facilitated, rather than inhibited, by exposure to mild naturalistic stress. The same stress blocked the induction of LTP. The effects of such stress were short lasting: acclimatization to, or removal from, the conditions that facilitated LTD induction led to a rapid loss of the ability to elicit this form of plasticity. The time window in which LTD could be reliably elicited was prolonged by inducing anaesthesia immediately after the stress. These data reveal that even brief exposure to mild stress can produce a striking shift in the susceptibility to synaptic plasticity in the awake animal.
504 citations
TL;DR: In this paper, the authors studied the growth of perturbations in a cold dark matter dominated universe with an extra scalar field, with an initial flat spectrum of adiabatic fluctuations.
Abstract: A scalar field with an exponential potential has the particular property that it is attracted into a solution in which its energy scales as the dominant component (radiation or matter) of the Universe, contributing a fixed fraction of the total energy density. We study the growth of perturbations in a cold dark matter dominated $\ensuremath{\Omega}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ universe with this extra field, with an initial flat spectrum of adiabatic fluctuations. The observational constraints from structure formation are satisfied as well, or better, than in other models, with a contribution to the energy density from the scalar field ${\ensuremath{\Omega}}_{\ensuremath{\varphi}}\ensuremath{\sim}0.1$ which is small enough to be consistent with entry into the attractor prior to nucleosynthesis.
01 Mar 1997
TL;DR: The β-tungsten structure as discussed by the authors has a surface area that is approximately 0.3% less than that of Kelvin's structure, which is a counter-example of a structure analogous to that of some clathrate compounds.
Abstract: Kelvin's conjecture, that a b.c.c. arrangement of his minimal tetrakaidecahedron divides space into equal cells of minimum surface area, has stood for over one hundred years. We have found a counter-example, in the form of a structure analogous to that of some clathrate compounds and also related to the β-tungsten structure. Its surface area is approximately 0.3% less than that of Kelvin's structure.
TL;DR: This chapter presents microbiological assay for serum, plasma, and red cell folate, using cryopreserved, microtiter plate method, and the final working standard concentration of 500 ng/liter is presented.
Abstract: Publisher Summary This chapter presents microbiological assay for serum, plasma, and red cell folate, using cryopreserved, microtiter plate method. In the 500-ml beaker a solution of 0.5% (w/v) sodium ascorbate is prepared by dissolving 2.5 g of sodium ascorbate in 500 ml of water. This solution is used for preparing the working standard and for all assay dilutions. The working standard is prepared in the following way—a universal tube containing stock standard solution is brought to room temperature and a 50- μ l aliquot is taken and diluted to 100 ml with 0.5% (w/v) sodium ascorbate in a volumetric flask. This solution is mixed thoroughly, then 5 ml is taken and diluted to 100 ml with 0.5% (w/v) sodium ascorbate in a second volumetric flask to give a final working standard concentration of 500 ng/liter. Duplicate 50- μ l aliquots of serum or plasma or duplicate 25- μ l aliquots of whole-blood lysate are pipetted into labeled 4-ml polypropylene tubes. Using the adjustable repetitive sampling pipette the aliquots are diluted to a total of 1 ml with 0.5% (w/v) sodium ascorbate.
TL;DR: The metal-insulator transition is attributed to a modification of the spin-dependent potential J HsnS associated with the onset of magnetic order at the Curie point TC as discussed by the authors.
Abstract: The metal-insulator transition is mixed-valence manganites of the ~La0.7Ca0.3!MnO3 type is ascribed to a modification of the spin-dependent potential J HsnS associated with the onset of magnetic order at TC . Here JH is the on-site Hund’s-rule exchange coupling of an e g electron with s51/2 to the t 2g ion core with S 53/2. Above TC, the e g electrons are localized by the random spin-dependent potential and conduction is by variable-range hopping. Over the whole temperature range, the resistivity varies as ln( r/r ‘) 5@T0$12( M/ MS) 2 %/T# 1/4 , where M/ MS is the reduced magnetization. The temperature and field dependence of the resistivity deduced from the molecular-field theory of the magnetization reproduces the experimental data over a wide range of temperature and field. @S0163-1829~97!04513-X# Interest in mixed-valence manganites of the ~La0.7Ca0.3!MnO3 type has revived 1 with the observations of large negative magnetoresistive effects, 2,3 especially in suitably annealed thin films. 4 The magnetoresistance is greatest in the vicinity of the Curie point TC of ferromagnetic compositions which exhibit ‘‘metallic’’ ~temperatureindependent! conduction at low temperatures and thermally activated conduction above TC . These compositions have a structure which is a variant of the cubic perovskite cell where the Mn-O bond lengths are unequal and Mn-O-Mn bond angles differ from 180 °. 5 Their electronic properties are re
TL;DR: The hypothesis that NO plays an important role in synaptic transmission is supported and some but not all previously contradictory results are explained.
TL;DR: It is shown that a single burst of five pulses given on the positive phase of tail pinch-triggered theta rhythm reliably induced LTP in the stratum radiatum of the hippocampus of urethane-anesthetized rats.
Abstract: Long-term potentiation (LTP) of synaptic transmission induced by high-frequency stimulation (HFS) is considered to be a model for learning processes; however, standard HFS protocols consisting of long trains of HFS are very different from the patterns of spike firing in freely behaving animals. We have investigated the ability of brief bursts of HFS triggered at different phases of background theta rhythm to mimic more natural activity patterns. We show that a single burst of five pulses at 200 Hz given on the positive phase of tail pinch-triggered theta rhythm reliably induced LTP in the stratum radiatum of the hippocampus of urethane-anesthetized rats. Three of these bursts saturated LTP, and 10 bursts occluded the induction of LTP by long trains of HFS. Burst stimulation on the negative phase or at zero phase of theta did not induce LTP or long-term depression. In addition, stimulation with 10 bursts on the negative phase of theta reversed previously established LTP. The results show that the phase of sensory-evoked theta rhythm powerfully regulates the ability of brief HFS bursts to elicit either LTP or depotentiation of synaptic transmission. Furthermore, because complex spike activity of approximately five pulses on the positive phase of theta rhythm can be observed in freely moving rats, LTP induced by the present theta-triggered stimulation protocol might model putative synaptic plastic changes during learning more closely than standard HFS-induced LTP.
TL;DR: A repeated serum folic acid response is likely to be found in many women complying with the advice to take 400 micrograms folic Acid/d to prevent the occurrence of neural tube defects, particularly in consumers in nontargeted populations of large amounts of fortified foods.
TL;DR: The results suggest that a substantial minority of people in general populations may have increased folate needs, and place doubts on the validity of assuming "normality" for nutrient requirements in any general population.
TL;DR: A fortification programme that delivered 400 micrograms folic acid daily to women would protect against NTD, but at the expense of unnecessarily high exposure for many people.
TL;DR: By incorporating finite element models into iterative computer procedures, adaptive biological processes can be simulated opening an exciting field of research by allowing scientists to test proposed 'rules' or 'algorithms' for tissue growth, adaptation and degeneration.
TL;DR: Physical exercise levels are highly variable across samples of relatively privileged young Europeans from different countries, and associations with other health behaviors and with emotional well-being suggest that regular physical exercise is consistent with a healthy lifestyle.
TL;DR: In this article, the question of l'alimentation a ete marginalisee a l'interieur des debats sur l'agriculture and le developpement rural is discussed.
Abstract: La question de l'alimentation a ete marginalisee a l'interieur des debats sur l'agriculture et le developpement rural : ceci est en partie du a la division du travail a l'interieur de la discipline - qui traite l'agriculture comme une branche de la sociologie du travail et de la production - et en partie la consequence de l'acceptation - par les sociologues ruraux et les decideurs - de l'idee selon laquelle la tâche des agriculteurs dans les pays developpes est moins de produire des denrees alimentaires que de produire du paysage. S'appuyant sur les idees du mouvement irlandais pour l'agriculture biologique, cet article montre que la nourriture demeure un enjeu hautement signifiant a la fois du point de vue de la consommation et du point de vue du developpement, et qu'elle demande a faire l'objet d'une conceptualisation renouvelee a l'interieur d'une sociologie rurale de genre holiste. Il suggere egalement que si la question de l'alimentation n'est pas placee au centre des questions environnementales, l'agriculture biologique tend a etre assimilee a un conservatisme ecologique, ce qui sape sa critique des formes classiquement productivistes d'agriculture
TL;DR: Within the psychology of religion two main groups of theories have been advanced to account for gender differences in religiosity: social or contextual influences which shape different responses to religion among men and women as discussed by the authors.
TL;DR: Dosing of β-amyloid precursor protein fragments 1–40 and 1–42 and the C-terminal fragment CT105 greatly shortened the duration of high frequency stimulation-induced long-term potentiation (LTP) of field excitatory postsynaptic potentials in the CA1 area, contributing to the cognitive deficits in Alzheimer's disease.
Abstract: The effects of beta-amyloid precursor protein (beta-APP) fragments on plasticity of glutamtatergic synaptic transmission were examined in the hippocampus of urethane anaesthetized rats. I.c.v. injection of beta-amyloid (A beta) 1-40 and 1-42 and the C-terminal fragment CT105 greatly shortened the duration of high frequency stimulation-induced long-term potentiation (LTP) of field excitatory postsynaptic potentials in the CA1 area. Whereas in vehicle injected animals LTP was stable over a 5 h recording period, doses of these peptides (A beta 1-40, 0.4 and 3.5 nmol; A beta1-42, 0.01 nmol; CT105, 0.05 nmol) which did not affect baseline synaptic transmission abolished LTP within 3-5 h. The reduced duration of this form of synaptic plasticity may contribute to the cognitive deficits in Alzheimer's disease.
TL;DR: It is shown that Clf33 inhibits ADP-induced, fibrinogen-dependent platelet aggregation in a concentration-dependent manner and inhibits adhesion of platelets to immobilized fibr inogen under fluid shear stress, indicating that the binding sites for the platelet integrin and the staphylococcal adhesin overlap.
Abstract: The ability of Staphylococcus aureus to adhere to adsorbed fibrinogen and fibrin is believed to be an important step in the initiation of biomaterial and wound-associated infections. In this study, we show that the binding site in fibrinogen for the recently identified S. aureus fibrinogen-binding protein clumping factor (ClfA) is within the C-terminus of the fibrinogen γ chain. S. aureus Newman cells expressing ClfA adhered to microtitre wells coated with recombinant fibrinogen purified from BHK cells, but did not adhere to wells coated with a purified recombinant fibrinogen variant where the 4 C-terminal residues of the γ chain were replaced by 20 unrelated residues. In addition, a synthetic peptide corresponding to the 17 C-terminal amino acids of the fibrinogen γ chain effectively inhibited adherence of ClfA-expressing cells to fibrinogen. In western ligand blots, a recombinant truncated ClfA protein called Clf33 (residues 221–550) recognized intact recombinant fibrinogen γ chains, but failed to recognize recombinant fibrinogen γ chains where the 4 C-terminal amino acids were altered by deletion or substitution. Previous studies have shown that the C-terminal domain of fibrinogen γ chains contains a binding site for the integrin αIIbβ3 (glycoprotein gpIIb/IIIa) receptor on platelets [Kloczewiak, M., Timmons, S., Bednarek, M. A., Sakon, M. & Hawiger, J. (1989) Biochemistry 28, 2915–1919; Farrell, D. H., Thiagarajan, P., Chung, D. W. & Davie, E. W. (1992) Proc. Natl Acad. Sci. USA 89, 10729–10732; Hettasch, J. M., Bolyard, M. G. & Lord, S. T. (1992) Thromb. Haemostasis 68, 701–706]. We now show that Clf33 inhibits ADP-induced, fibrinogen-dependent platelet aggregation in a concentration-dependent manner and inhibits adhesion of platelets to immobilized fibrinogen under fluid shear stress, indicating that the binding sites for the platelet integrin and the staphylococcal adhesin overlap. The interaction between Clf33 and fibrinogen was further characterized using the BIAcore biosensor. When soluble Clf33 was allowed to bind to immobilized fibrinogen, a Kd of 0.51 ± 0.19 μM was experimentally determined using equilibrium binding data. It was also shown that the synthetic C-terminal γ-chain peptide effectively inhibited this interaction.
TL;DR: The random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was shown to be a convenient typing method for S. marcescens for the first time, and 73 different RAPD patterns with good reproducibility were obtained.
Abstract: Serratia marcescens has emerged in the last few years as an important nosocomial pathogen. Many methods for typing this organism have been described. In this study the random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was shown to be a convenient typing method for S. marcescens. Different combinations of primers previously used for typing other gram-negative bacilli were assessed. The combination of primer HLWL-74 and 1254 gave distinguishable patterns for different serotypes and proved to be the most satisfactory. By applying this combination to 175 isolates of S. marcescens, which could be classified into 38 groups on the basis of serotyping and phage typing, 73 different RAPD patterns with good reproducibility were obtained. This is, to our knowledge, the first application of the method to a large collection of S. marcescens representing a wide range of serotypes.
TL;DR: What caused the recent costly wave of banking system failures in developing and transition economies is the key to preventing a recurrence, and a comprehensive prevention policy must take account of each type of epidemic.
Abstract: Understanding what caused the recent costly wave of banking system failures in developing and transition economies is the key to preventing a recurrence. It is important to distinguish between epidemics of the macroeconomic and micro-economic varieties, and between these and the syndrome of endemic failure, associated with pervasive government involvement. Each type has its characteristic warning signs - the availability of the relevant indicators is discussed in some detail - and a comprehensive prevention policy must take account of each. Thus, for example, it is unwise to defer macroeconomic stabilisation in the hope of concealing banking sector weakness. Likewise, a rigorous application to developing and transition economies of the consensus approach to microeconomic regulation should not be deferred. Political interference is the Achilles heel of any regulatory system: among other mechanisms, it may be possible to use disclosure rules and the pressures of globalisation to increase the political attraction of regulatory enforcement.
TL;DR: The similarities between the implant incorporation process found in the experiment and its simulation with the computer model demonstrate that the hypothesis that distortional strain and interstitial fluid flow are the mechanical stimuli governing tissue differentiation is viable from a regulatory point of view.
Abstract: Loosening of implants in bone is commonly associated with a development of fibrous interface tissues, due to interface gaps and a lack of mechanical stability. It has been postulated that the differentiation of these tissues to fibrocartilage or bone is governed by mechanical stimuli. The objective of our research is to unravel these relationships to the extent that the question whether an implant will loosen can be answered from initial conditions determined by implant and interface morphology, and functional loads. In this project we studied the hypothesis that distortional strain and interstitial fluid flow are the mechanical stimuli governing tissue differentiation. For that purpose, a biomechanical regulatory model was developed and used in association with a finite element code to simulate animal experiments with implants moving in bone. The similarities between the implant incorporation process found in the experiment and its simulation with the computer model demonstrate that our hypothesis is viable from a regulatory point of view.
TL;DR: The identification, using a technique known as messenger RNA differential display, of an extracellular signalling molecule, previously described as the pancreatic secreted protein Reg-2, that is expressed solely in regenerating and developing rat motor and sensory neurons is reported here.
Abstract: Motor neurons are the only adult mammalian neurons of the central nervous system to regenerate following injury. This ability is dependent on the environment of the peripheral nerve and an intrinsic capacity of motor neurons for regrowth. We report here the identification, using a technique known as messenger RNA differential display, of an extracellular signalling molecule, previously described as the pancreatic secreted protein Reg-2, that is expressed solely in regenerating and developing rat motor and sensory neurons. Axon-stimulated Schwann cell proliferation is necessary for successful regeneration, and we show that Reg-2 is a potent Schwann cell mitogen in vitro. In vivo, Reg-2 protein is transported along regrowing axons and inhibition of Reg-2 signalling significantly retards the regeneration of Reg-2-containing axons. During development, Reg-2 production by motor and sensory neurons is regulated by contact with peripheral targets. Strong candidates for peripheral factors regulating Reg-2 production are cytokines of the LIF/CNTF family, because Reg-2 is not expressed in developing motor or sensory neurons of mice carrying a targeted disruption of the LIF receptor gene, a common component of the receptor complexes for all of the LIF/CNTF family.
TL;DR: Byrne et al. as mentioned in this paper reported results from the first nationwide study of bullying behavior in primary and post-primary schools in Ireland carried out during 1993-94. But their results were limited to a small subset of primary and secondary schools.
Abstract: Most of our knowledge of bullying behaviour in Irish schools has been gained from empirical studies carried out in Dublin (Byrne, 1994a; O’Moore & Hillery, 1989). The present paper, reports results from the first nationwide study of bullying behaviour in primary and post-primary schools in Ireland carried out during 1993–94. The results presented include data on the incidence of being bullied and bullying others, year differences, gender differences, types of bullying, where bullying occurs, whether teachers or parents are aware and pupils attitudes to bullying. Some correlations of bullying are also examined, in particular school size, class size, ability groupings and the social composition of school. Finally implications for intervention against bullying are discussed.