Showing papers by "Trinity College, Dublin published in 1995"
TL;DR: In this paper, a randomized, placebo-controlled trial of betamethasone administration in women who were expected to give birth preterm found a statistically significant reduction in the frequency of respiratory distress in babies born before 32 weeks gestation and a fivefold reduction in neonatal mortality among preterm babies born after corticosteroid administration compared with administration of a placebo.
833 citations
TL;DR: The study shows that an abnormality in homocysteine metabolism, apparently related to methionine synthase, is present in many women who give birth to children with neural-tube defects and suggests that the most effective periconceptional prophylaxis to prevent neural- tube defects may require B 12 as well as folic acid.
664 citations
TL;DR: In this paper, the authors argue that while learning strategies and learner training can play an important supporting role in the development of learner autonomy, the decisive factor will always be the nature of the pedagogical dialogue and the role of the teacher.
607 citations
TL;DR: In this paper, the Coulomb and spin-dependent potentials localize the electrons in wave packets that are large on the scale of the Mn-Mn separation transport in the magnetically localized state involves zero point-energy assisted hopping or tunneling of electrons from one weakly localized wave packet to another.
Abstract: Mixed-valence manganites $({{A}^{3+}}_{07}{{B}^{2+}}_{03})\mathrm{Mn}{\mathrm{O}}_{3}$ exhibit a resistivity peak with giant negative magnetoresistance below the Curie point Residual resistivity ranges from 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ to 8\ifmmode\times\else\texttimes\fi{}${10}^{3}$ \ensuremath{\Omega} m, but the electronic heat capacity when $A=\mathrm{Y}\mathrm{or}\mathrm{La}$ is that of a normal $d$-band metal; $\ensuremath{\gamma}\ensuremath{\approx}6$ mJ ${\mathrm{mole}}^{\ensuremath{-}1}$${\mathrm{K}}^{\ensuremath{-}2}$ Spatial fluctuations in the Coulomb and spin-dependent potentials localize the ${e}_{g}\ensuremath{\uparrow}({\ensuremath{\sigma}}^{*})$ electrons in wave packets that are large on the scale of the Mn-Mn separation Transport in the magnetically localized state involves zero-point-energy assisted hopping or tunneling of electrons from one weakly localized wave packet to another
425 citations
04 Jul 1995
TL;DR: The requirements that an effective image watermarking scheme must possess are specified, followed by a review of current and novel techniques based on image transforms.
Abstract: A watermark is all invisible mark placed on an image that can only be detected when the image is compared with the original. This mark is designed to identify both the source of a document as well as its intended recipient. This paper discusses various techniques for embedding such marks in grey scale and colour digital images. It begins specifying the requirements that an effective image watermarking scheme must possess, followed by a review of current and novel techniques based on image transforms.
344 citations
TL;DR: In the case of the Maastricht referenda in France and Denmark, the apparent unpopularity of the European project in fact appears to have been nothing of the kind, but instead to have reflected the popularity of ruling parties in both countries.
Abstract: The referenda conducted in France and Denmark in 1992 to ratify the Maastricht Treaty are often seen as giving evidence of ‘true’ attitudes towards Europe. In this paper we dispute this assumption, presenting evidence that shows referenda in Parliamentary systems with disciplined party governments to be subject to what we call a ‘lockstep’ phenomenon in which referendum outcomes become tied to the popularity of the government in power, even if the ostensible subject of the referendum has little to do with the reasons for government popularity (or lack of popularity). In the case of the Maastricht referenda in France and Denmark, the apparent unpopularity of the European project in fact appears to have been nothing of the kind, but instead to have reflected the unpopularity of ruling parties in both countries. A referendum conducted at about the same time in Ireland, where the government was more popular, achieved a handsome majority, as did the referendum conducted a year later in Denmark after a more pop...
335 citations
TL;DR: Genetic screening could identify women who will require folic acid supplements to reduce their risk of having a child with an NTD, and explains the association between some NTDs and elevated homocysteine, given that the reductase is important in homocy steine metabolism.
Abstract: It is now well-established that folic acid, taken peri-conceptionally, can reduce the risk of neural tube defects (NTDs). Recent work has demonstrated that an abnormality of homocysteine metabolism is a critical factor. The gene for 5,10 methylenetetrahydrofolate reductase, an enzyme important in homocysteine metabolism, was studied in relation to NTDs. To determine the frequency of the allele for the thermolabile form of the reductase, DNA samples were collected from people with NTDs, parents of people with NTDs, and normal controls. Of 82 people with NTDs, 15 (18.3%) were homozygous for the abnormal, thermolabile allele. This was significantly higher (p = 0.01) than the rate of 6.1% in the control population (odds ratio 3.47, 95% CI 1.28-9.41). This is the first specific genetic abnormality to be identified in NTDs. It explains the association between some NTDs and elevated homocysteine, given that the reductase is important in homocysteine metabolism. It also explains how folic acid supplementation prevents some NTDs, by overcoming a partial block in the conversion of 5,10 methylenetetrahydrofolate to 5 methyltetrahydrofolate. Genetic screening could identify women who will require folic acid supplements to reduce their risk of having a child with an NTD.
330 citations
Proceedings Article•
20 Aug 1995
TL;DR: Two new deletion strategies are proposed that can take both competence and performance into consideration during deletion, and they may cause problems for CBR system competence.
Abstract: The utility problem occurs when the cost associated with searching for relevant knowledge outweighs the benefit of applying this knowledge. One common machine learning strategy for coping with this problem ensures that stored knowledge is genuinely useful, deleting any structures that do not contribute to performance in a positive sense, and essentially limiting the size of the knowledge-base. We will examine this deletion strategy in the context of case-based reasoning (CBR) systems. In CBR the impact of the utility problem is very much dependant on the size and growth of the case-base; larger case-bases mean more expensive retrieval stages, an expensive overhead in CBR systems. Traditional deletion strategies will keep performance in check (and thereby control the classical utility problem) but they may cause problems for CBR system competence. This effect is demonstrated experimentally and in reply two new deletion strategies are proposed that can take both competence and performance into consideration during deletion.
323 citations
TL;DR: Wild‐type fnbA andfnbB genes cloned seperately on a multicopy plasmid were each able to restore fully the adhesion‐defective phenotype of the 8325‐4fnbA fnbB mutant, demonstrating that both fnb genes are expressed in S. aureus and that both contribute to the ability of strain 8325-4 to adhere to fibronectin‐coated surfaces.
Abstract: Staphylococcus aureus 8325-4 has the potential to express two distinct cell wall-associated fibronectin-binding proteins called FnBPA and FnBPB. In order to test if both proteins are expressed in S. aureus and if both are required for promoting bacterial adhesion to fibronectin-coated surfaces, insertion mutations were isolated in each gene. A DNA fragment encoding tetracycline resistance was inserted into fnbA and a fragment encoding erythromycin resistance was inserted into fnbB. A double fnbAfnbB mutant was also constructed. The fnbA and fnbB single mutants showed no significant reduction in their adhesion to polymethylmethacrylate coverslips that had been coated in vitro with fibronectin. However, the double mutant was completely defective in adhesion. Monospecific antibodies directed against the non-conserved N-terminal regions of both proteins confirmed the lack of expression of FnBPs in the mutant strains. Wild-type fnbA and fnbB genes cloned seperately on a multicopy plasmid were each able to restore fully the adhesion-defective phenotype of the 8325-4 fnbAfnbB mutant. This demonstrates that both fnb genes are expressed in S. aureus and that both contribute to the ability of strain 8325-4 to adhere to fibronectin-coated surfaces. The double mutant was also defective in adhesion to coverslips that had been removed from tissue cages implanted subcutaneously in guinea-pigs, which suggests that fibronectin is important in promoting attachment of S. aureus to biomaterial in vivo.
315 citations
TL;DR: It now appears that natural selection shapes codon usage in some multicellular species (e.g. Drosophila and Caenorhabditis), and that regional variations in mutation biases occur in yeast.
Abstract: Silent sites (positions that can undergo synonymous substitutions) in protein-coding genes can illuminate two evolutionary processes First, despite being silent, they may be subject to natural selection Among eukaryotes this is exemplified by yeast, where synonymous codon usage patterns are shaped by selection for particular codons that are more efficiently and/or accurately translated by the most abundant tRNAs; codon usage across the genome, and the abundance of different tRNA species, are highly co-adapted Second, in the absence of selection, silent sites reveal underlying mutational patterns Codon usage varies enormously among human genes, and yet silent sites do not appear to be influenced by natural selection, suggesting that mutation patterns vary among regions of the genome At first, the yeast and human genomes were thought to reflect a dichotomy between unicellular and multicellular organisms However, it now appears that natural selection shapes codon usage in some multicellular species (eg Drosophila and Caenorhabditis), and that regional variations in mutation biases occur in yeast Silent sites (in serine codons) also provide evidence for mutational events changing adjacent nucleotides simultaneously
290 citations
Posted Content•
TL;DR: It is found that for both men and women, problem drinking results in reduced employment and increased unemployment.
Abstract: The misuse of alcoholic beverages ('problem drinking') has been demonstrated to result in enormous economic costs; most of these costs have been shown to be reduced productivity in the labor market. The purpose of this paper is to present sound structural estimates of the relationship between various measures of problem drinking and of employment and unemployment. The sample of approximately 15,000 observations is drawn from the 1988 Alcohol Survey of the National Health Interview Survey, the first dataset that enables nationally- representative estimates of alcohol abuse and dependence consistent with generally accepted medical criteria. The structural estimates of the effects of problem drinking on employment and labor market participation are obtained using methods proposed by Amemiya and by Heckman and MaCurdy. For our sample of males ages 25 to 59, we find that using the instrumental variable approach suggests that the negative impact of problem drinking on employment is even greater than that estimated using the OLS approach. Interestingly, the IV estimates on the samples of females change the sign from a positive impact of problem drinking on employment to a negative impact. Thus although the conclusions drawn from raw data comparisons and OLS regressions differ by gender, the IV estimates are very similar for men and women. For women, the unobserved heterogeneity masks the negative impact of problem drinking on employment when using OLS estimation methods.
TL;DR: The results from this study suggest that the reactive oxygen model of NF kappa B activation may be restricted to certain cell types and that the presence of such a system is not required for the activation of NFKappa B by IL1 and TNF.
TL;DR: The cloning and sequencing of the gene clfA encoding the fibrinogen receptor (clumping factor, ClfA) of S. aureus strain Newman showed that the gene product was responsible for the clumping of bacteria in soluble fibr inogen and for the adherence of bacteria to solid‐phase fibrins.
Abstract: The ability of Staphylococcus aureus to bind to fibrinogen and fibrin is believed to be an important factor in the initiation of foreign-body and wound infections Recently, we reported the cloning and sequencing of the gene clfA encoding the fibrinogen receptor (clumping factor, ClfA) of S aureus strain Newman and showed that the gene product was responsible for the clumping of bacteria in soluble fibrinogen and for the adherence of bacteria to solid-phase fibrinogen This was confirmed here by showing that antibodies raised against purified Region A inhibited both of these properties Also, immunofluorescent microscopic analysis of wild-type Newman and a clfA::Tn917 mutant of Newman with anti-ClfA Region A sera confirmed that Region A is exposed on the bacterial cell surface Furthermore, polystyrene beads coated with the Region A protein formed clumps in soluble fibrinogen showing that the ClfA protein alone is sufficient for the clumping phenotype Western immunoblotting with anti-ClfA Region A antibodies identified the native ClfA receptor as a 185 kDa protein that was released from the cell wall of S aureus by lysostaphin treatment A single extensive ligand-binding site was located within Region A of the ClfA protein Truncated ClfA proteins were expressed in Escherichia coli Lysates of E coli and proteins that had been purified by affinity chromatography were tested for (i) their ability to bind fibrinogen in Western ligand blotting experiments, (ii) for their ability to inhibit clumping of bacteria in fibrinogen solution and adherence of bacteria to solid-phase fibrinogen, and (iii) for their ability to neutralize the blocking activity of anti-ClfA Region A antibody These tests allowed the ligand-binding domain to be localized to a 218-residue segment (residues 332-550) within Region A
TL;DR: The findings suggest that advanced periodontitis patients with multiple residual probing depths > or = 6 mm at re-evaluation run a greater risk of developing sites with additional attachment loss than patients with few such residual depths.
Abstract: 16 advanced periodontitis patients were subjected to initial periodontal treatment and monitored every 3rd month during 42 months. Clinical characteristics at baseline and during the 42-month maintenance period were investigated for their association with probing attachment loss over the 42-month period, both on a patient level and on a site level. On a patient level, averaged full-mouth plaque and bleeding on probing scores over the maintenance interval showed little association with probing attachment loss. Little association was also observed for % sites with depth > or = 6 mm at baseline. However, a notable relationship was seen for % sites > or = 6 mm at 3 months. This finding initiated a separation of the 16 subjects into 2 groups based upon % sites > or = 6 mm at 3 months (groups 'high' and 'low'). Site level analyses for these groups showed little association between frequent presence of plaque at the sites over the maintenance interval and probing attachment loss. Frequent bleeding on probing showed limited relationship with attachment loss for group 'low', but an appreciable association for group 'high'. The findings suggest that advanced periodontitis patients with multiple residual probing depths > or = 6 mm at re-evaluation run a greater risk of developing sites with additional attachment loss than patients with few such residual depths. For such higher risk patients, bleeding on probing at maintenance examinations may be a useful indicator of subsequent deterioration at a site level.
TL;DR: Invention of breeds, long advocated, are now being established and concepts originally formulated for the quantification of species diversity are being applied, which will provide valuable resources for the future of agriculture, especially in the developing world.
Abstract: Growing awareness of the importance of conserving the biodiversity of livestock breeds is paralleled by genetic advances that will help objective planning of conservation. Inventories of breeds, long advocated, are now being established and concepts originally formulated for the quantification of species diversity are being applied. The breeds thus conserved will provide valuable resources for the future of agriculture, especially in the developing world.
TL;DR: This article examined the effects of a revising goal to ''add information'' on the revising behavior and writing performance of 5th and 6th grade students with writing and learning problems, and found that the goal to add information resulted in greater improvement in text quality than the general revision goal.
Abstract: This study examined the effects of a revising goal to «add information» on the revising behavior and writing performance of 5th- and 6th-grade students with writing and learning problems. The authors also examined whether procedural assistance in meeting the goal to add information would enhance students'performance. In comparison to students assigned a general revising goal to make their paper better, students assigned a goal to add information made more meaning-based changes, particularly additions, when revising their papers. Most importantly, the goal to add information resulted in greater improvement in text quality than the general revising goal. Use of the procedural facilitator to accomplish the goal to add information, however, did not appreciably enhance students'revising behavior or the quality of their text
TL;DR: Although sugars intake varies among these major developed regions, the consistent inverse relation between fat and sugars intake and the scarcity of individuals achieving dietary guidelines raises serious questions regarding current dietary recommendations.
TL;DR: It is suggested that each tumor type has a characteristic AI that reflects innate tumor cell susceptibility to undergo apoptosis, and there was a wide range in the AI for different tumor types.
Abstract: Little quantitative data exist on the extent of apoptosis (genetically-mediated cell deletion) in different human tumor types. Hematoxylin and eosin-stained paraffin sections of 102 malignant tumors (58 types) were evaluated for apoptotic cells and apoptotic bodies, using the 40x objective with a calibrated eye-piece and avoiding necrotic zones. The percentage of apoptotic cells and apoptotic bodies in the total number of tumor cells examined was designated as the apoptotic index (AI) for each case. There was a wide range in the AI for different tumor types: 45 tumors had AI < 1% and 93 had an AI of < 7%. In 107 additional tumors (11 types), the AI was determined to be within the same low, intermediate, or high range as the index cases. Apoptotic nuclear material was usually more prominent than mitoses. These results suggest that each tumor type has a characteristic AI that reflects innate tumor cell susceptibility to undergo apoptosis. Additional data are needed to determine whether significant variations in AI correlate with altered proliferative indices, aberrant oncogene/tumor suppressor gene expression, and standard clinicopathologic variables.
TL;DR: It is suggested that Helicobacter pylori plays an important role in the symptoms of nonulcer dyspepsia and is associated with more additional treatments than those with eradication.
Abstract: Helicobacter pylori is present in up to 87% of patients with nonulcer dyspepsia. This study assessed the effect of eradicatingHelicobacter pylori infection on the symptoms of nonulcer dyspepsia at four weeks and one year after treatment. Dyspepsia was assessed on the frequency and severity of six symptoms [epigastric pain (night and day), nausea and vomiting, upper abdominal discomfort, and regurgitation] where each symptom was scored from 0 to 4.Helicobacter pylori status was assessed before treatment and four weeks after treatment with histology and microbiology, and at one year with a carbon-13 urea breath test. Eighty-three patients (23 males, 60 females; mean age 56.3 years; mean symptom duration 3.6 months) with nonulcer dyspepsia andHelicobacter pylori infection entered the study. Seventy-five were available at one year follow-up. Four weeks after treatment, the mean symptom score improved in those with eradication (6.95–2.3,P=0.01,N=41) or persistent infection (6.69–3.0,P=0.015,N=42). At one year, those with persistentHelicobacter pylori infection (N=38, score 5.24) had a higher score than those remaining clear of infection (N=24, score 1.4,P<0.0001) and those with reinfection (N=13, score 2.2,P<0.0001). In addition, persistentHelicobacter pylori infection was associated with more additional treatments than those with eradication (34/38 versus 4/37,P<0.001). These results suggest thatHelicobacter pylori plays an important role in the symptoms of nonulcer dyspepsia.
TL;DR: It is suggested that increased gastric production of IL-8 and TNF may be implicated in the pathogenesis of H pylori associated gastroduodenal disease.
Abstract: AIMS--To investigate the role of interleukin-8 (IL-8) and tumour necrosis factor (TNF) in patients infected with Helicobacter pylori. METHODS--The study population comprised 52 patients with dyspepsia attending for upper gastrointestinal endoscopy. Of these patients, 35 were infected with H pylori. IL-8 and TNF concentrations in plasma, gastric juice, and gastric biopsy homogenate supernatant fluid were measured by radioimmunoassay and L929 cell bioassay, respectively. RESULTS--The concentrations of IL-8 and TNF in gastric juice and gastric biopsy homogenates were substantially greater in patients infected with H pylori. In H pylori positive patients IL-8 concentrations in gastric juice and gastric biopsy homogenates were higher in those with moderate gastritis than in those with mild gastritis. There was a positive correlation between IL-8 and TNF concentrations in gastric juice and gastric biopsy homogenate supernatant fluid from H pylori positive patients. There were no significant differences between H pylori positive and negative patients with respect to IL-8 and TNF plasma concentrations. CONCLUSION--This study suggests that increased gastric production of IL-8 and TNF may be implicated in the pathogenesis of H pylori associated gastroduodenal disease.
TL;DR: In this article, a review of optical spectroscopy applied to semiconductor surfaces and interfaces is presented, with emphasis on studies of systems which have been well-characterised using conventional surface probes.
TL;DR: Results provide direct evidence that beta-amyloid selectively interacts with the potentially neurotoxic NMDA receptor via a postsynaptic site and it is proposed that this action may help explain the synaptic changes seen in Alzheimer's disease.
Abstract: The effect of beta-amyloid on alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor-mediated glutamatergic excitatory postsynaptic currents measured with whole-cell voltage-clamp techniques, was investigated in the rat dentate gyrus in vitro. Application of beta-amyloid (1-40) by extracellular perfusion (200 nM) or intracellularly via the recording pipette (100 nM) resulted in a gradual enhancement of the NMDA receptor-mediated synaptic currents which did not reverse on washout. Basal AMPA receptor-mediated transmission, resting membrane potential or input resistance of the granule cells did not change. These results provide direct evidence that beta-amyloid selectively interacts with the potentially neurotoxic NMDA receptor via a postsynaptic site. It is proposed that this action may help explain the synaptic changes seen in Alzheimer's disease.
TL;DR: In this paper, a dc SQUID magnetometer was used to study the relaxations of six ferrofluids differing in particle size using nonlinear ln( t ) behavior in freeze-dried samples.
TL;DR: Binding to mononucleotides is suggested to be primarily stabilised by π‐π stacking interactions between the planar dyes and the nucleobases: for thionine and azure B there also appears to be H‐bonds between the exocyclic amines and the sugar–phosphates conferring extra stability.
Abstract: The interactions of methylene blue, azure B, and thionine with calf thymus DNA, [poly (dG-dC)]2, [poly(dA-dT)]2, and the constituent mononucleotides 2′-deoxyguanosine-5′-monophosphate(dGMP), 2′-deoxyadenosine-5′-monophosphate(dAMP), 2′-deoxycytidine-5′-monophosphate(dCMP), and thymidine-5′-monophosphate(dTMP) have been studied by steady-state absorption spectroscopy and with equilibrium dialysis. Scatchard plots for binding of the dyes to the nucleic acid polymers were convex downward at low binding ratios, characteristic of intercalation, and binding constants for this mode were calculated under conditions of varying ionic strength. For each of the dyes, binding constants with [poly(dG-dC)]2 and [poly(dA-dT)]2 were of the same order of magnitude, so that previously reported (G-C) preferentially is not very marked. At high binding ratios, the Scatchard plots did not return to the abscissa but curved upward, indicative of a weaker cooperative binding mode, occurring under conditions where the dye is in excess, which is suggested to be external stacking of the dye molecules promoted by the polyanion. The dependence of the absorption spectra on added salt demonstrated a shift in the strong binding mode for the three dyes with [poly(dA-dT)]2 with increasing ionic strength, while with [poly(dG-dC)]2 this does not occur. The dyes were found to bind to purine but not pyrimidine mononucleotides with dGMP and dAMP, 1:1 complexes were formed initially and also 1:2 dye/nucleotide complexes with increasing nucleotide concentrations. Under low salt conditions, binding to dAMP was slightly stronger than to dGMP for the three dyes studied, while at high ionic strength, when the binding constants are significantly lower, all binding constants become very similar. Binding to mononucleotides is suggested to be primarily stabilised by π-π stacking interactions between the planar dyes and the nucleobases: for thionine and azure B there also appears to be H-bonds between the exocyclic amines and the sugar–phosphates conferring extra stability. Neither increasing the number of phosphate groups on the nucleotides nor changing from deoxyribose to ribose sugars had any significant effect on the binding constants. © 1995 John Wiley & Sons, Inc.
TL;DR: The internal consistency reliability, unidimensionality and construct validity of the Francis scale of attitude toward Christianity (adult) was supported among four samples of undergraduate students: 378 in the U.K., 212 in the USA, 255 in Australia and 231 in Canada as discussed by the authors.
TL;DR: The results urge caution in the use of herbimycin A as a specific tyrosine kinase inhibitor and suggest that the development of agents that selectively modify p50 may have potential as a means of inhibiting NF-κB-dependent gene transcription.
TL;DR: Age was found to be a significant factor in relation to infection with Toxocara, and males were significantly more infected than females, as were the inhabitants of rural schools versus urban schools.
Abstract: The seroprevalence of toxocariasis was investigated in 2129 school children ranging in age from 4 to 19 years. Infection, as measured by titre, was found to be high compared to values obtained from children in other countries, with 31% having a titre of > or = 1:50 and 3.1% having titres of > or = 1:800. Relationships between seroprevalence and host factors including age, sex and location, and risk factors including geophagia, thumbsucking and pet ownership were explored. Age was found to be a significant factor in relation to infection with Toxocara. Males were significantly more infected than females, as were the inhabitants of rural schools versus urban schools. The percentage of seropositive children varied widely from school to school. Geophagia and pet ownership were found to be significantly associated with toxocariasis. Logistic regression analysis was used to model the relative contribution of these factors to infection with Toxocara. While this analysis identified factors which were highly significantly associated with Toxocara titre, the odds ratios were generally low indicating the low specificity of the model.
TL;DR: The studies suggest that coactivation of the mGluR and N MDAR are required for induction of LTP of both the AMPAR- and NMDAR-mediated synaptic transmission, which appears to be dependent on coincident activation of the NMDar and mGLUR.
Abstract: Whole-cell patch-clamp recordings of evoked excitatory postsynaptic currents (EPSCs) were made from granule cells of the rat dentate gyrus in vitro. Tetanic stimulation in control media evoked a statistically identical long-term potentiation (LTP) of both the AMPA and NMDA receptor-mediated components of the dual component EPSC (AM-PAR and NMDAR EPSCs), as shown by a similar percentage increase in both components when measured at a holding potential of -30 mV, and also by an identical time course of the pre- and post-LTP induced EPSC at -30 mV and -70 mV. Application of the selective metabotropic glutamate receptor (mGluR) agonist 1S,3R-ACPD induced a transient depression followed by a rapid onset LTP of both the AMPAR and the NMDAR components of the dual component EPSC. The ACPD- and tetanically induced LTP of the AMPAR EPSC was NMDAR dependent, being abolished by the NMDAR antagonist AP5. Tetanic stimulation, and application of ACPD, also induced a relatively rapid onset LTP of the pharmacologically isolated NMDAR EPSC. Such tetanically and ACPD-induced LTP of the isolated NMDAR EPSC was also dependent on NMDAR activation, being strongly inhibited by AP5. The tetanically and the ACPD-induced LTP of the NMDAR EPSC were dependent on protein kinase C (PKC) stimulation, being strongly inhibited by the PKC inhibitor PKCI (19–31). The studies suggest that coactivation of the mGluR and NMDAR are required for induction of LTP of both the AMPAR- and NMDAR-mediated synaptic transmission. Moreover, LTP of the NMDAR-mediated synaptic transmission appears to be dependent on coincident activation of the NMDAR and mGluR.
TL;DR: Both the ACPD-and the low frequency stimulation (LFS)-induced LTD and DP were inhibited in the presence of the mGluR antagonist (+)-alpha-methyl-4-carboxyphenylglycine (MCPG), demonstrating the necessity for the activation of metabotropic glutamate receptors in the induction of LTD/DP.