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M J West

Publications and source records attributed to M J West.

At least 19 recordsLinked to original sources
PubMed2006

EBV EBNA 2 stimulates CDK9-dependent transcription and RNA polymerase II phosphorylation on serine 5.

EBNA 2 is one of only five viral genes essential for the infection and immortalization of human B cells by the cancer-associated virus Epstein-Barr virus (EBV). EBNA 2 activates cellular and viral transcription and associates with components of the basal transcription apparatus and a number of coactivators. We provide the first evidence to show that the mechanism of transcriptional activation by EBNA 2 also involves phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (pol II). We found that transcriptional activation by EBNA 2 was inhibited by a dominant-negative mutant of the pol II CTD kinase, CDK9, and by low concentrations of the CDK9 inhibitor 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole. Moreover, using chromatin immunoprecipitation assays we demonstrated that EBNA 2 stimulates both pol II recruitment and pol II phosphorylation on serine 5 of the CTD in vivo. These results identify a new step in the transcription cycle that is subject to regulation by a key EBV-encoded transcription factor and highlight CDK9 inhibitors as potential anti-EBV agents.

Alcohol Oxidoreductases↗
PubMed2006

Inflammation, heat shock proteins and periodontal pathogens in atherosclerosis: an immunohistologic study.

BACKGROUND: Inflammation is a significant component of atherosclerosis lesions. Bacteria, including periodontopathogens, have been demonstrated in atherosclerotic plaques and cross-reactivity of the immune response to bacterial GroEL with human heat shock protein 60 has been suggested as a link between infections and atherosclerosis. METHODS: In this study, the nature of the inflammatory infiltrate and the presence of human heat shock protein 60 and GroEL were examined in 31 carotid endarterectomy specimens. Additionally, monoclonal antibodies were used to detect the presence of six bacteria, including those implicated in periodontal disease. RESULTS: The inflammatory cell infiltrate of the lesions was dominated by CD14(+) macrophages and CD4(+) T cells. Most cells of the infiltrate as well as the endothelium were HLA-DR(+), indicating activation; however, there was an absence of CD25 expression, demonstrating that the activated T cells were not proliferating. Few CD1a(+) and CD83(+) cells were noted. Human heat shock protein 60 expression was evident on endothelial cells and cells with the appearance of smooth muscle cells and lymphocytes. GroEL and bacteria were detected within intimal cells. Chlamydia pneumoniae, Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia, Prevotella intermedia, and Actinobacillus actinomycetemcomitans were found in 21%, 52%, 34%, 34%, 41%, and 17% of arteries, respectively. CONCLUSION: These results give evidence for a specific immune response associated with atherosclerosis. Whether bacteria initiate the observed inflammation in atherosclerotic lesions is not clear; however, the present study shows that maintenance of inflammation may be enhanced by the presence of periodontopathic bacteria.

Aggregatibacter actinomycetemcomitans↗
PubMed2005

Histopathology and fibrillin-1 distribution in severe early onset Marfan syndrome.

Marfan syndrome (MFS) is an autosomal dominant condition which may involve the cardiovascular, ocular, skeletal, and other systems. Mutations causing MFS are found in the FBN1 gene, encoding fibrillin-1, an extracellular matrix protein involved in microfibril formation. In the most severe cases, mutations are generally found in exons 24-32, and children with these mutations usually die in the first years of life, of cardiopulmonary failure. We present clinical, molecular and histopathological studies on a patient with severe early onset MFS. He has a mutation in exon 25 of FBN1, a G>A transition at nucleotide position 3131 that converts the codon TGC, coding for cysteine at position 1044, to TAC, coding for tyrosine (C1044Y). This has resulted in abnormalities of the extracellular matrix and a severe clinical phenotype, although he has survived to the age of 14 years.

Adolescent↗
PubMed2005

Immersion autometallographic tracing of zinc ions in Alzheimer beta-amyloid plaques.

An easy to perform autometallographic technique (AMG) for capturing zinc ions in Alzheimer plaques is presented. The possibility of visualizing loosely bound or free zinc ions in tissue by immersion autometallography (iZnS(AMG)) is a relatively recent development. The iZnS(AMG) staining is caused by zinc-sulphur nanocrystals created in 1-2 mm thick brain slices that are immersed in a 0.1% sodium sulphide, 3% glutaraldehyde phosphate buffered solution, the NeoTimm Solution (NTS), for 3 days. When the zinc-sulphur nanocrystals are subsequently silver-enhanced by autometallography, the plaques are readily identified as spheres of dark interlacing strands of different sizes, embedded in the pattern of zinc-enriched terminals. The zinc specificity of the iZnS(AMG) technique was tested by immersion of brain slides in the chelator DEDTC prior to the NTS immersion. The iZnS(AMG) detection of zinc ions is easily standardized and can be used in the quantification of plaques with stereological methods. This technique is the first to detect zinc in plaques in the cerebellum of transgenic PS1/APP mice and the first to detect zinc ions in plaques and dystrophic neurites at electron microscopical levels.

Aged↗
PubMed2005

Estimators of the precision of stereological estimates: an example based on the CA1 pyramidal cell layer of rats.

Because of the complex and dynamic structure of the brain, there is perhaps no other organ system in which the application of stereological methods can contribute so much with regard to understanding normal and pathological processes. In order to design the studies in an optimal manner, with regard to the number of individuals, sections, probes, and to be able to critically evaluate the stereological studies made by others, it is important for neuroscientists to have an understanding of the precision or reproducibility of a stereological estimation procedure. This precision or reproducibility is often referred to as the coefficient of error of the estimate, which is a statistical expression for the size of the standard error of the mean of repeated estimates, relative to the mean of the estimates. Like the 'margin of error' associated with public opinion polls, it indicates how much the estimate would vary if it were repeated numerous times. It is difficult and time consuming to empirically derive the coefficient of error of estimates made of features observed in histological preparations. To overcome this obstacle, it is common practice to try to get a feeling for the precision of an estimate by estimating the coefficient of error itself. In this paper, we will compare and discuss the coefficient of error of estimates of volume and cell number made with different numbers of sections and probes in the CA1 pyramidal cell layer of the rat hippocampus. The conclusions drawn from this analysis indicate that, using practically feasible and anatomically sensible sampling schemes, the Gundersen-Jensen coefficient of error estimator or the 'Split-Sample' coefficient of error estimator can provide useful information about the precision of stereological estimates even in highly irregular brain regions and requires little work.

Algorithms↗
PubMed2005

Cross-reactivity of GroEL antibodies with human heat shock protein 60 and quantification of pathogens in atherosclerosis.

BACKGROUND/AIMS: Chronic infections such as those caused by Chlamydia pneumoniae and periodontopathic bacteria such as Porphyromonas gingivalis have been associated with atherosclerosis, possibly due to cross-reactivity of the immune response to bacterial GroEL with human heat shock protein (hHSP) 60. METHODS: We examined the cross-reactivity of anti-GroEL and anti-P. gingivalis antibodies with hHSP60 in atherosclerosis patients and quantified a panel of six pathogens in atheromas. RESULTS: After absorption of plasma samples with hHSP60, there were variable reductions in the levels of anti-GroEL and anti-P. gingivalis antibodies, suggesting that these antibodies cross-reacted with hHSP60. All of the artery specimens were positive for P. gingivalis. Fusobacterium nucleatum, Tannerella forsythia, C. pneumoniae, Helicobacter pylori, and Haemophilus influenzae were found in 84%, 48%, 28%, 4%, and 4% of arteries, respectively. The prevalence of the three periodontopathic microorganisms, P. gingivalis, F. nucleatum and T. forsythia, was significantly higher than that of the remaining three microorganisms. CONCLUSIONS: These results support the hypothesis that in some patients, cross-reactivity of the immune response to bacterial HSPs including those of periodontal pathogens, with arterial endothelial cells expressing hHSP60 may be a possible mechanism for the association between atherosclerosis and periodontal infection.

Aged↗
PubMed2002

Cultures, genes, and neurons in the development of song and singing in brown-headed cowbirds (Molothrus ater).

In brown-headed cowbirds, Molothrus ater, as in many songbird species, vocalizations are fundamental to reproduction. In our studies, experiments utilizing different social housing regimes and geographic comparisons have indicated the social learning of males' vocalizations and associated abilities to use vocalizations effectively during the breeding season. Here, we describe studies indicating roles of cultural and genetic background, and of social influences from females, on male vocal development. These influences can interact with neural regions, including song learning and song control nuclei, but also visual-processing nuclei, in the development of signaling. We argue that a developmental systems approach to the study of vocal behavior provides a structure to organize these different influences and how they may interact with one another over development. A systems approach requires that researchers study the social context in which signals and signalers develop - both the ontogenetic arena in which young animals learn their signals from older animals, and the functional arena in which young and older animals socially interact with one another.

Animals↗
PubMed2002

Stereological length estimation using spherical probes.

Lineal structures in biological tissue support a wide variety of physiological functions, including membrane stabilization, vascular perfusion, and cell-to-cell communication. In 1953, Smith and Guttman demonstrated a stereological method to estimate the total length density (Lv) of linear objects based on random intersections with a two-dimensional sampling probe. Several methods have been developed to ensure the required isotropy of object-probe intersections, including isotropic-uniform-random (IUR) sections, vertical-uniform-random (VUR) slices, and isotropic virtual planes. The disadvantages of these methods are the requirements for inconvenient section orientations (IUR, VUR) or complex counting rules at multiple focal planes (isotropic virtual planes). To overcome these limitations we report a convenient and straightforward approach to estimate Lv and total length, L, for linear objects on tissue sections cut at any arbitrary orientation. The approach presented here uses spherical probes that are inherently isotropic, combined with unbiased fractionator sampling, to demonstrate total L estimation for thin nerve fibres in dorsal hippocampus of the mouse brain.

Animals↗
PubMed2001

Stereological estimates of number and length of capillaries in subdivisions of the human hippocampal region.

The hippocampal formation is a neuroanatomically well-defined region of the brain involved in memory processes. In view of the functional importance of the region and its involvement in a number of brain pathologies, including Alzheimer's disease and temporal lobe epilepsy, a quantitative description of its vascular supply represents an important first step in evaluating the involvement of vascular changes in these phenomena. Unbiased estimates of the length and connectivity of the vascular supply of brain regions have not been described previously. The total number, total length, and distribution of the diameters of capillaries were estimated in the five major subdivisions of the hippocampal formation (fascia dentata, hilus, CA3-2, CA1, and subiculum) in 5 normal males, 52-84 years of age. These estimates were used to derive several other structural parameters. Both the primary and the derived parameters were used to make inter- and intra-individual comparisons. For each of the five major subdivisions from each individual, the volume was estimated using the Cavalieri principle. The total capillary length was estimated on 3-microm-thick plastic isotropic uniform random sections. Using a topological definition of a capillary unit and the optical disector, total capillary number was estimated in 40-microm-thick plastic sections. Length-and number-weighted three-dimensional diameter distributions were obtained from the thin and thick plastic sections, respectively. In each subdivision the total length of capillaries was correlated with previously obtained data on the number of neurons in the same subdivisions of the same individuals. Intersubdivisional differences were observed, in that the hilus of the dentate gyrus had fewer capillaries per unit volume than the other four subdivisions. Interindividual comparisons indicate that the interindividual variances are of a magnitude suitable for sensitive group comparisons. The design-based stereological methods that were used in the analyses can provide a basis for a new unbiased approach to the estimation of vascular parameters in well-defined regions of the brain.

Aged↗
PubMed2001

Cultural transmission of vocal traditions in cowbirds (Molothrus ater) influences courtship patterns and mate preferences.

In this study, the authors tested the cultural transmission of vocal traditions in cowbirds (Molothrus ater). Young cowbirds from a South Dakota (SD) population were housed over winter with adults of the SD population or with adults from an Indiana (IN) population. Song differences between the original SD and IN adult models were acquired by South Dakota culture (SDC) and Indiana culture (INC) males, respectively, and were transmitted to a 2nd cultural generation of birds. During playback tests of SDC and INC songs, SD females gave more copulatory responses to SDC songs. Finally, males with SD-like songs courted SDC females preferentially in breeding season tests, whereas males with IN-like songs courted INC females preferentially. These results indicate that the transmission of vocal traditions plays a fundamental role in the courtship patterns and mating decisions of cowbirds.

Animals↗
PubMed2001

Activation of human immunodeficiency virus transcription in T cells revisited: NF-kappaB p65 stimulates transcriptional elongation.

Human immunodeficiency virus type 1 (HIV-1) is able to establish a persistent latent infection during which the integrated provirus remains transcriptionally silent. Viral transcription is stimulated by NF-kappaB, which is activated following the exposure of infected T cells to antigens or mitogens. Although it is commonly assumed that NF-kappaB stimulates transcriptional initiation alone, we have found using RNase protection assays that, in addition to stimulating initiation, it can also stimulate elongation from the HIV-1 long terminal repeat. When either Jurkat or CCRF/CEM cells were activated by the mitogens phorbol myristate acetate and phytohemagglutinin, elongation, as measured by the proportion of full-length transcripts, increased two- to fourfold, even in the absence of Tat. Transfection of T cells with plasmids carrying the different subunits of NF-kappaB demonstrated that the activation of transcriptional elongation is mediated specifically by the p65 subunit. It seems likely that initiation is activated because of NF-kappaB's ability to disrupt chromatin structures through the recruitment of histone acetyltransferases. To test whether p65 could stimulate elongation under conditions where it did not affect histone acetylation, cells were treated with the histone deacetylase inhibitor trichostatin A. Remarkably, addition of p65 to the trichostatin A-treated cell lines resulted in a dramatic increase in transcription elongation, reaching levels equivalent to those observed in the presence of Tat. We suggest that the activation of elongation by NF-kappaB p65 involves a distinct biochemical mechanism, probably the activation of carboxyl-terminal domain kinases at the promoter.

Acetylation↗
PubMed2001

Design based stereological methods for estimating the total number of objects in histological material.

The principle that formed the basis of the most popular "assumption based" stereological methods for counting cells that were available prior to the advent of the more recently developed "design based" methods will be described in general terms. The major weaknesses inherent in the older methods will be described, along with how they have been eliminated by the design based methods.

Animals↗
PubMed2000

Pravastatin therapy and the risk of stroke.

BACKGROUND: Several epidemiologic studies have concluded that there is no relation between total cholesterol levels and the risk of stroke. In some studies that classified strokes according to cause, there was an association between increasing cholesterol levels and the risk of ischemic stroke and a possible association between low cholesterol levels and the risk of hemorrhagic stroke. Recent reviews of trials of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors have suggested that these agents may reduce the risk of stroke. METHODS: In a double-blind trial (the Long-Term Intervention with Pravastatin in Ischaemic Disease study), we compared the effects of pravastatin on mortality due to coronary heart disease (the primary end point) with the effects of placebo among 9014 patients with a history of myocardial infarction or unstable angina and a total cholesterol level of 155 to 271 mg per deciliter (4.0 to 7.0 mmol per liter). Our goal in the present study was to assess effects on stroke from any cause and nonhemorrhagic stroke, which were secondary end points. RESULTS: There were 419 strokes among 373 patients over a follow-up period of six years. A total of 309 strokes were classified as ischemic, 31 as hemorrhagic, and 79 as of unknown type. Among the patients given placebo, the risk of stroke was 4.5 percent, as compared with 3.7 percent among those given pravastatin (relative reduction in risk, 19 percent; 95 percent confidence interval, 0 to 34 percent; P=0.05). Non-hemorrhagic stroke occurred in 4.4 percent of the patients given placebo, as compared with 3.4 percent of those given pravastatin (reduction in risk, 23 percent; 95 percent confidence interval, 5 to 38 percent; P=0.02). Pravastatin had no effect on hemorrhagic stroke (incidence, 0.2 percent in the placebo group vs. 0.4 percent in the pravastatin group; P=0.28). CONCLUSIONS: Pravastatin has a moderate effect in reducing the risk of stroke from any cause and the risk of nonhemorrhagic stroke in patients with previous myocardial infarction or unstable angina.

Adult↗
PubMed2000

Remodeling of hippocampal synapses after hippocampus-dependent associative learning.

The aim of this study was to determine whether hippocampus-dependent associative learning involves changes in the number and/or structure of hippocampal synapses. A behavioral paradigm of trace eyeblink conditioning was used. Young adult rabbits were given daily 80 trial sessions to a criterion of 80% conditioned responses in a session. During each trial, the conditioned (tone) and unconditioned (corneal airpuff) stimuli were presented with a stimulus-free or trace interval of 500 msec. Control rabbits were pseudoconditioned by equal numbers of random presentations of the same stimuli. Brain tissue was taken for morphological analyses 24 hours after the last session. Synapses were examined in the stratum radiatum of hippocampal subfield CA1. Unbiased stereological methods were used to obtain estimates of the total number of synapses in this layer as well as the area of the postsynaptic density. The data showed that the total numbers of all synaptic contacts and various morphological subtypes of synapses did not change in conditioned animals. The area of the postsynaptic density, however, was significantly increased after conditioning in axospinous nonperforated synapses. This structural alteration may reflect an addition of signal transduction proteins (such as receptors and ion channels) and the transformation of postsynaptically silent synapses into functional ones. The findings of the present study indicate that cellular mechanisms of hippocampus-dependent associative learning include the remodeling of existing hippocampal synapses. Further studies examining various time points along the learning curve are necessary to clarify the issue of whether these mechanisms also involve the formation of additional synaptic contacts.

Animals↗
PubMed2000

Reduced number of striatal neurons expressing preprosomatostatin mRNA in rats with oral dyskinesias after long-term haloperidol administration.

Neuroleptic-induced oral dyskinesia in rats, a putative analogue to human tardive dyskinesia, may be due to degeneration within the striatum. Using unbiased stereological methods, a decreased number of striatal neurons expressing preprosomatostatin mRNA was observed only in rats that developed pronounced oral dyskinesias after 30 weeks of haloperidol administration. The amount of preprosomatostatin mRNA in each striatal neuron, measured in terms of optical densities of individual neurons, was not affected by haloperidol. A tendency toward a reduction in the number of NADPH-diaphorase positive neurons was observed in rats receiving haloperidol. These results indicate that the mechanism by which neuroleptics induce oral dyskinesias in rats, and perhaps tardive dyskinesia in humans, involves a functional disruption and possibly damage of a subpopulation of interneurons in the striatum.

Animals↗
PubMed2000

Optimising care of acute myocardial infarction: results of a regional quality improvement project.

The effects of a quality improvement intervention were evaluated in a before-after time-series study of 649 consecutive patients suffering acute myocardial infarction (AMI) in the West Moreton Health District over 2.5 years from March 1996 through to August 1998. After a 6-month baseline period, clinical practice guidelines were issued followed by sequential feedback to providers of clinical indicator data over a 1-year period. Resultant changes in practice were then evaluated during a 12-month post-intervention period. The proportion of eligible patients receiving early thrombolysis, lipid-lowering drugs and cardiac rehabilitation increased, respectively, from 30.8 to 70.0% (P = 0.001), from 23.4 to 56.4% (P = 0.003), and from 23.6 to 54.3% (P = 0.003). The in-hospital death rate, incidence of postinfarct angina and mean length of stay decreased, respectively, from 15.8 to 8.6% (P = 0.02), from 30.1 to 14.3% (P < 0.001), and from 7.4 to 6.3 days (P = 0.001). Despite the absence of control groups, the present study suggested that clinical guidelines combined with feedback of clinical indicators were useful in improving quality of care.

Age Factors↗