Biomedical subjects
Publications and source records attributed to C Knight.
Although C reactive protein is intimately involved with the pathogenic mechanisms that drive acute coronary syndromes, there is no evidence that it is helpful for identifying patient groups who might benefit from particular treatment strategies
OBJECTIVES: To analyse the relation between serum glucose concentration and hospital outcome across the whole spectrum of acute coronary syndromes. METHODS: This was a prospective cohort study of 2127 patients presenting with acute coronary syndromes. The patients were stratified into quartile groups (Q1 to Q4) defined by serum glucose concentrations of 5.8, 7.2, and 10.0 mmol/l. The relation between quartile group and major in-hospital complications was analysed. RESULTS: The proportion of patients with acute myocardial infarction increased incrementally across the quartile groups, from 21.4% in Q1 to 47.9% in Q4 (p < 0.0001). The trend for frequency of in-hospital major complications was similar, particularly left ventricular failure (LVF) (Q1 6.4%, Q4 25.2%, p < 0.0001) and cardiac death (Q1 0.7%, Q4 6.1%, p < 0.0001). The relations were linear, each glucose quartile increment being associated with an odds ratio of 1.46 (95% confidence interval (CI) 1.27 to 1.70) for LVF and 1.52 (95% CI 1.17 to 1.97) for cardiac death. Although complication rates were higher for a discharge diagnosis of acute myocardial infarction than for unstable angina, there was no evidence that the effects of serum glucose concentration were different for the two groups, there being no significant interaction with discharge diagnosis in the associations between glucose quartile and LVF (p = 0.69) or cardiac death (p = 0.17). Similarly there was no significant interaction with diabetic status in the associations between glucose quartile and LVF (p = 0.08) or cardiac death (p = 0.09). CONCLUSION: Admission glycaemia stratified patients with acute coronary syndromes according to their risk of in-hospital LVF and cardiac mortality. There was no detectable glycaemic threshold for these adverse effects. The prognostic correlates of admission glycaemia were unaffected by diabetic status and did not differ significantly between patients with acute myocardial infarction and those with unstable angina.
Our laboratory has determined the DNA sequence and transcriptional expression pattern of a mouse cDNA clone termed Nma/BAMBI. This clone encodes a highly conserved protein with 89% identity to the human homologue (termed Nma) and 78% similarity to the Xenopus homologue (termed BAMBI) at the predicted amino acid level. Nma/BAMBI encodes a 260-amino-acid transmembrane protein that has homology to the transforming growth factor (TGF) beta type I receptor family. This protein contains an extracellular ligand binding domain, a 24-amino-acid transmembrane domain, and a short intracellular domain that lacks a functional serine/threonine kinase domain. It is believed that Nma/BAMBI is important in the negative regulation of TGF beta signal transduction pathways during development and has implications in tumor progression. We have determined the genomic organization of the mouse Nma/BAMBI gene and confirmed the chromosomal mapping to human chromosome 10 and mouse chromosome 2. Furthermore, we report the production and utilization of an anti-peptide antibody in preliminary immunohistochemical analysis of an ameloblastoma.
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OBJECTIVE: To determine whether there are specific cytochrome P450 (CYP2) alleles that increase susceptibility to scleroderma in individuals who have been exposed to organic solvents. METHODS: CYP alleles at 2 loci, 2E1 and 2C19, were compared in 7 patients who had developed scleroderma after exposure to solvents versus 71 patients with scleroderma without solvent exposure ("sporadic" disease) and 106 population controls. RESULTS: The 2E1*3 allele was found in 2 of the 7 patients who had been exposed to organic solvents, with a greater frequency than occurred in either the disease controls or the population controls (odds ratio [95% confidence interval] 9.1 [1.5-59.1] and 10.2 [1.8-62.2], respectively). All 7 patients with solvent exposure carried the 2C19EM genotype, compared with 89% of patients with sporadic scleroderma. CONCLUSION: Our results suggest that alleles at CYP loci may be involved in increasing susceptibility to scleroderma among subjects who have been exposed to organic solvents.
This study aimed to identify genes or gene products associated with high lean muscle mass in bovines that may serve as potential markers for selection. An animal with a genetic predisposition to high lean muscle mass, the Belgium Blue, was chosen as a model to compare with the Holstein Friesian, a model that does not. Two-dimensional polyacrylamide gel electrophoresis analysis was utilized to compare the exhibited skeletal muscle proteome between the two animal types at two stages of foetal development. A previously uncharacterized polymorphism of a high expression myofibrillar protein, myosin light chain 1 fast (MLC-1f), was observed. The characterization of this polymorphism revealed a two amino acid insertion in a part of the protein that has been implicated in modulating myosin S1 ATPase activity. Furthermore, this polymorphism was shown to be the product of two alleles that are codominant. Screening studies were carried out on selected herds and showed a very high frequency of one allele. Both isoforms of MLC-1f were produced by recombinant means and purified. The recombinant proteins were exchanged into purified myosin hexamers that were then subject to assays measuring ATP consumption. The sensitivity of the assay utilized could not reveal any significant difference in ATPase activity between hexamers containing one or the other isoform.
PURPOSE: Single-cell polymerase chain reaction (PCR) requires efficient amplification and accurate detection. We compare the accuracy of heteroduplex, fluorescent-fragment, and fluorescent single-strand conformation polymorphism (F-SSCP) analysis as detection systems for analysis of a PCR assay developed for preimplantation genetic diagnosis. METHODS: A single-cell, fluorescent multiplex PCR assay was developed for the cystic fibrosis delta F508 mutation and the short tandem repeat, D21S11. Detection systems were compared by analyzing blinded PCR products. RESULTS: Amplification rates for cystic fibrosis were 89% by heteroduplex and 91% by fragment analysis, while it was 72% for D21S11 by fragment analysis. No difference in allele dropout was detected for cystic fibrosis by any method (2%). Overall accuracy was high, > 97%, although SSCP was the least accurate. CONCLUSIONS: Heteroduplex and fragment analysis proved equal in the diagnosis of a single amplified locus. We determined that fragment analysis allows maximal accuracy of detection and permits analysis of a second loci, controlling for DNA contamination and allelic dropout.
OBJECTIVE: To assess the rate of progression of pulmonary hypertension (PHT) in systemic sclerosis (SSc) and its bearing on mortality. METHODS: A retrospective record review of 930 patients with SSc attending a specialist centre was carried out. Those at risk for both idiopathic and secondary PHT were assessed by serial Doppler echocardiography. Mortality data were reviewed. RESULTS: The cumulative prevalence of PHT was 13%. Pressures remained static in most cases. The mortality among those with a single pressure reading of 30 mmHg or higher was 20% at 20 months. An increased mortality risk was associated with high initial pressures and rising pressures. Rapid pressure rises occurred more frequently in limited than in diffuse SSC. CONCLUSIONS: The prevalence of PHT in SSc is high and the detection of PHT at any time in the disease course is associated with substantial mortality. These results demonstrate the value of echocardiographic screening for PHT in all patients with SSC.
Degenerate oligonucleotides to consensus serine kinase functional domains previously identified a novel, partial rabbit tooth cDNA (Zeichner-David et al., 1992) that was used in this study to identify a full-length mouse clone. A 1390-base-pair cDNA clone was isolated encoding a putative 260-amino-acid open reading frame containing a hydrophobic 25-amino-acid potential transmembrane domain. This clone shares some homology with the TGF-beta type I receptor family, but lacks the intracellular kinase domain. DNA database analysis revealed that this clone has 86% identity to a newly isolated human gene termed non-metastatic gene A and 80% identity to a Xenopus cDNA clone termed BMP and activin membrane bound inhibitor. Here we report the mouse Nma/BAMBI cDNA sequence, the tissue expression pattern, and confirmed expression in dental cell lines. This study demonstrates that Nma/BAMBI is a highly conserved protein across species and is expressed at high levels during odontogenesis.
Recent reports showing that circadian light cues may induce gene-specific patterns of expression in periventricular hypothalamic neurons has extended the functional correlates of light-pulse stimuli, which are conventionally restricted to circadian phase-setting actions within the suprachiasmatic nucleus (ScN). The aims of the present study were, first, to broaden these observations to the protein level using an Egr-1/NGFI-A antibody, and second to investigate the cell-type specificity of induction with respect to associated hypophysiotrophic neurons. In order to co-localize Egr-1 with neuroendocrine peptides, a same-species, double immunofluorescence protocol has been used. The Egr-1 antibody used for immunohistochemistry was first characterized by Western analysis, and we have shown that the C19 antisera detects a single 75 kDa protein species, which has a primarily nuclear subcellular localization. Immunohistochemical analysis has shown that Egr-1 protein is markedly induced by a 1 h nocturnal light pulse both in the body of the suprachiasmatic nucleus and in a dorsal ScN zone, which extends up into the periventricular nucleus (PeN). In contrast, induction of Egr-1 was not observed within the arcuate region of the hypothalamus. Double immunofluorescence histochemistry has shown that Egr-1 is extensively, although not exclusively, co-localized with somatostatin in PeN neurons. The selective induction of the 75 kDa protein product of the egr-1 gene in PeN somatostatinergic neurons, as contrasted with hypophysiotrophic (somatostatin and growth hormone-releasing hormone [GH-RH]) neurons of the arcuate nucleus is indicative of a cell- and stimulus-specific neuroendocrine paradigm, which may be used to address temporal characteristics of somatostatin function that determine pulsatile growth-hormone secretion.
BACKGROUND: Blood flow to the rat ventral prostate gland is drastically reduced during the very early period after castration, and this reduction coincides with the appearance of striking degenerative changes within the prostatic vascular system. These early effects on the prostate vascular system are likely to be important for the subsequent regression of the ventral prostate that occurs in response to castration. Since the endothelial cells of the ventral prostate do not express androgen receptor protein (AR), we proposed that these early effects might be indirectly mediated by changes in the local expression of vascular regulatory factors. In order to evaluate whether vascular endothelial growth factor-A (VEGF-A) might be among the primary mediators of these effects, we measured expression of VEGF-A mRNA and protein in the rat ventral prostate gland prior to and within the first 3 days after castration. METHODS: Ventral prostate tissues were obtained from control (unoperated) rats, sham-operated rats, or rats at sequential daily intervals (1-3 days) after castration. A quantitative RNase protection assay and a comparative RT-PCR assay were used to evaluate the extent to which the expression of VEGF-A mRNA in the ventral prostate was affected by castration. In situ immunohistochemistry, using an anti-VEGF-A antibody, was performed to localize VEGF-A protein in the various cells of the tissue. Western blot analysis and a quantitative ELISA assay using anti-VEGF-A antibodies were performed to determine how VEGF-A protein expression in the rat ventral prostate was affected by castration. RESULTS: Results of VEGF-A mRNA analysis in the rat ventral prostate gland during the first 3 days after castration showed a biphasic change characterized by a transient reduction of VEGF-A mRNA expression (by approximately 50%) on the second day after castration that was restored to higher than control levels by the third day after castration. Immunohistochemical analysis for VEGF-A in control and castrated ventral prostates showed that the prostatic epithelial and smooth muscle cells were the major source of VEGF-A expression in this tissue. Quantitative analysis of VEGF-A protein expression by Western blot and ELISA methods confirmed a biphasic change in the expression of the polypeptide that correlated well with the results of the mRNA analyses. CONCLUSIONS: VEGF-A expression in the ventral prostate gland of the Sprague-Dawley rat is downregulated on the second day after castration but returns to control levels by the third day after castration. Since critical changes in the ventral prostate vascular system are already evident by 1 day after castration, we believe that these findings indicate that VEGF-A is not likely to be the critical or sole mediator of the early effects of castration on the vascular system of the rat ventral prostate gland.
OBJECTIVE: To search for single-nucleotide polymorphisms in the interleukin-8 (IL-8) and IL-8 receptor CXCR-1 and CXCR-2 genes, and to compare their distribution among patients with systemic sclerosis (SSc) with fibrosing alveolitis (FASSc) or without fibrosing alveolitis (NFASSc), or patients with cryptogenic fibrosing alveolitis (CFA), and normal healthy subjects. METHODS: Fifty control subjects were screened for potential polymorphisms by using polymerase chain reaction in association with sequence-specific primers incorporating mismatches at the 3' end. The novel polymorphisms were subsequently examined in British Caucasian subjects, including 194 healthy controls, 71 patients with CFA, and 128 patients with SSc who were further subdivided into 78 FASSc patients and 50 NFASSc patients. RESULTS: Three novel biallelic polymorphisms were identified in the IL-8 gene (all in noncoding areas of the gene), 1 was found in the CXCR-1 gene (resulting in a conservative amino acid change), and 3 were observed in the CXCR-2 gene, of which the first resulted in a silent codon change and the others were in the 3' untranslated area of exon 3. Compared with controls, a significant increase in the frequency of the CXCR-2 +785 CC homozygote and of the CXCR-2 +1208 TT homozygote was found in the SSc patients (37% versus 22% [P = 0.01] and 33% versus 17% [P = 0.003], respectively). A subgroup analysis revealed this association to be significant both in the FASSc patients and in the NFASSc patients. CONCLUSION: This report describes an association between SSc and 2 polymorphisms occurring close to each other in the CXCR-2 gene. This finding and its functional significance need to be confirmed and analyzed in future studies.
OBJECTIVE: Early growth response protein-1 (Egr-1)/nerve growth factor-induced A (also known as Zif-268, Krox-24, TIS8, ZENK) is a zinc-finger transcription factor which, although expressed in a range of organ systems, has been shown to be essential only in the maintenance of fertility through actions within the endocrine system. In the present study we have investigated the anatomical basis for actions of Egr-1 in the adult anterior pituitary gland. DESIGN: Using female rats and mice as experimental models, we have used immunocytochemical and microscopic analysis to make observations of the cellular and sub-cellular localization of Egr-1 protein. METHODS: Immuno-(Western) blotting was first used to characterize the anterior pituitary proteins detected by a commercially available Egr-1 antibody. Subsequently, the antibody was used both singly and in combination with an LH beta-subunit antibody, for immunocytochemical localization studies in pituitary sections. RESULTS: The Egr-1 antiserum detected a single, major (primarily nuclear) 75 kDa protein band in Western blots of anterior pituitary extracts. Nuclear localization was confirmed by immunocytochemistry, which also demonstrated that the 75 kDa protein is localized to a minority sub-population of anterior pituitary cells in both rat and mouse. Dual immunocytochemical localization showed that the Egr-1 protein is primarily restricted to the nuclei of LH beta-subunit-expressing cells. CONCLUSIONS: Sub-cellular localization of Egr-1 to the nucleus is consistent with a direct role in transcriptional regulation of anterior pituitary function in the adult rat. Furthermore, a selective role in the physiological control of gonadotrophin gene expression is indicated.
The synthesis and vascular 5-HT(1B)-like receptor activity of a novel series of substituted 2, N-benzylcarboxamido-5-(2-ethyl-1-dioxoimidazolidinyl)-N, N-dimethyltryptamine derivatives are described. Modifications to the 5-ethylene-linked heterocycle and to substituents on the 2-benzylamide side chain have been explored. Several compounds were identified which exhibited affinity at the vascular 5-HT(1B)-like receptor of pK(B) > 7.0, up to 100-fold selectivity over alpha(1)-adrenoceptor affinity and 5-HT(2A) receptor affinity, and which exhibited a favorable pharmacokinetic profile. N-Benzyl-3-[2-(dimethylamino)ethyl]-5-[2-(4,4-dimethyl-2, 5-dioxo-1-imidazolidinyl)ethyl]-1H-indole-2-carboxamide (23) was identified as a highly potent, silent (as judged by the inability of angiotensin II to unmask 5-HT(1B)-like receptor-mediated agonist activity in the rabbit femoral artery), and competitive vascular 5-HT(1B)-like receptor antagonist with a plasma elimination half-life of approximately 4 h in dog plasma and with good oral bioavailability. The selectivity of compounds from this series for the vascular 5-HT(1B)-like receptors over other receptor subtypes is discussed as well as a proposed mode of binding to the receptor pharmacophore. It has been proposed that the aromatic ring of the 2, N-benzylcarboxamide group can occupy an aromatic binding site rather than the indole ring. The resulting conformation allows an amine-binding site to be occupied by the ethylamine nitrogen and a hydrogen-bonding site to be occupied by one of the hydantoin carbonyls. The electronic nature of the 2,N-benzylcarboxamide aromatic group as well as the size of substituents on this aromatic group is crucial for producing potent and selective antagonists. The structural requirement on the 3-ethylamine side chain incorporating the protonatable nitrogen is achieved by the bulky 2, N-benzylcarboxamide group and its close proximity to the 3-side chain.
The proteins expressed by a genome have been termed the proteome. By comparing the proteome of a disease-affected tissue with the proteome of an unaffected tissue it is possible to identify proteins that play a role in a disease process. The hippocampus is involved in the processing of short-term memory and is affected in Alzheimer's disease. Any comparative proteome analysis that can identify proteins important in a disease affecting the hippocampus requires the characterization of the normal hippocampal proteome. Therefore, we homogenised normal hippocampal tissue and separated the proteins by two-dimensional polyacrylamide gel electrophoresis (2DE). Seventy-two unique protein spots were collected from Coomassie blue-stained 2DE gels and subjected to in-gel digestion with trypsin, reversed-phase high-pressure liquid chromatography peptide separation, and N-terminal protein sequencing. Sufficient protein sequence was obtained to successfully characterize 66 of the 72 protein spots chosen (92%). Three of the 66 proteins were not present in any database (4.5%). The characterized proteins comprised two dominant functional groups, i.e., enzymes involved in intermediary cellular metabolism (40%), and proteins associated with the cytoskeleton (15%). The identity, molecular mass, isoelectric point, and relative concentration of the characterized proteins are described and constitute a partial proteome map of the normal human hippocampus.
OBJECTIVE: To identify combinations of easily acquired clinical variables, at first presentation with scleroderma, that would predict subsequent mortality. METHODS: In this prospective study of all new patients at one major scleroderma center, 280 patients with definite scleroderma (according to the American College of Rheumatology criteria) whose disease onset occurred from 1982 to 1991 and who were followed up to the end of 1996 were identified. Standardized data collection was performed at entry to obtain data on major clinical and laboratory variables. Vital status was determined by linkage to the National Death Index. RESULTS: At 5 years, 55 (26%) of 215 women and 21 (32%) of 65 men had died. Univariate analysis showed that older age, diffuse skin disease, higher skin score, low carbon monoxide diffusing capacity, abnormal electrocardiogram findings, proteinuria, hematuria, low hemoglobin level, elevated erythrocyte sedimentation rate (ESR), and presence of antitopoisomerase antibody were all associated with increased mortality. A logistic regression model, validated by Monte Carlo simulation, identified 3 factors, proteinuria, elevated ESR, and low carbon monoxide diffusing capacity, that in combination, had an accuracy of >80% in predicting mortality. The absence of these 3 factors was associated with 93% survival. CONCLUSION: A simple model has been developed that appears to accurately predict mortality over 5 years in a cohort of patients newly presenting with scleroderma.
The analysis of phenotypic change resulting from gene disruption following homologous recombination provides a powerful technique for the study of gene function. This technique has so far been difficult to apply to plants because the frequency of gene disruption following transformation with constructs containing DNA homologous to genomic sequences is low (0.01 to 0.1%). It has recently been shown that high rates of gene disruption (up to 90%) can be achieved in the moss Physcomitrella patens using genomic sequences of unknown function. We have used this system to examine the specificity of gene disruption in Physcomitrella using a member of the Cab multigene family. We have employed the previously characterised Cab gene ZLAB1 and have isolated segments of 13 other closely related members of the Cab gene family. In the 199-bp stretch sequenced, the 13 new members of the Cab family show an average of 8.5% divergence from the DNA sequence of ZLAB1. We observed 304 silent substitutions and 16 substitutions that lead to a change in the amino acid sequence of the protein. We cloned 1029 bp of the coding region of ZLAB1 (including 177 of the 199 bp with high homology to the 13 new Cab genes) into a vector containing a selectable hygromycin resistance marker, and used this construct to transform P. patens. In three of nine stable transformants tested, the construct had inserted in, and disrupted, the ZLAB1 gene. There was no discernible phenotype associated with the disruption. We have therefore shown that gene disruption is reproducible in P. patens and that the requirement for sequence homology appears to be stringent, therefore allowing the role of individual members of a gene family to be analysed in land plants for the first time.
Partial cDNA sequencing was used to obtain 169 expressed sequence tags (ESTs) in the moss, Physcomitrella patens. The source of ESTs was a random cDNA library constructed from 7 day-old protonemata following treatment with 10(-4) M abscisic acid (ABA). Analysis of the ESTs identified 69% with homology to known sequences, 61% of which had significant homology to sequences of plant origin. More importantly, at least 11 ESTs had significant similarities to genes which are implicated in plant stress-responses, including responses which may involve ABA. These included a cDNA associated with desiccation tolerance, two heat shock protein genes, one cold acclimation protein cDNA and five others that may be involved in either oxidative or chemical stress or both, i.e., Zn/Cu-superoxide dismutase, NADPH protochlorophyllide oxidoreductase (PorB), selenium binding protein, glutathione peroxidase and glutathione S transferase. Analysis of codon usage between P. patens and seed plants indicated that although mosses and higher plants are to a large extent similar, minor variations also exists that may represent the distinctiveness of each group.